JP3860531B2 - Noise suppression circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a noise suppression circuit that suppresses noise propagating on a conductive wire.
[0002]
[Prior art]
Power electronics devices such as switching power supplies, inverters, lighting circuits for lighting devices, and the like have a power conversion circuit that converts power. The power conversion circuit has a switching circuit that converts direct current into rectangular alternating current. For this reason, the power conversion circuit generates a ripple voltage having a frequency equal to the switching frequency of the switching circuit and noise associated with the switching operation of the switching circuit. This ripple voltage and noise adversely affect other devices. Therefore, it is necessary to provide a means for reducing ripple voltage and noise between the power conversion circuit and another device or line.
[0003]
As means for reducing ripple voltage and noise, a filter including an inductance element (inductor) and a capacitor, a so-called LC filter is often used. The LC filter includes a T-type filter and a π-type filter in addition to one having one inductance element and one capacitor. A general noise filter for electromagnetic interference (EMI) countermeasures is also a kind of LC filter. A general EMI filter is configured by combining discrete elements such as a common mode choke coil, a normal mode choke coil, an X capacitor, and a Y capacitor.
[0004]
Recently, power line communication has been considered promising as a communication technique used in building a communication network in the home, and its development is being promoted. In power line communication, communication is performed by superimposing a high-frequency signal on the power line. In this power line communication, noise is generated on the power line due to the operation of various electric / electronic devices connected to the power line, which causes a decrease in communication quality such as an increase in error rate. Therefore, a means for reducing noise on the power line is required. In power line communication, it is necessary to prevent a communication signal on the indoor power line from leaking to the outdoor power line. The LC filter is also used as means for reducing such noise on the power line or preventing a communication signal on the indoor power line from leaking to the outdoor power line.
[0005]
Noise that propagates through two conductive lines includes normal mode noise that causes a potential difference between the two conductive lines and common mode noise that propagates through the two conductive lines in the same phase.
[0006]
Patent Document 1 describes a line filter using a transformer. This line filter includes a transformer and a filter circuit. The secondary winding of the transformer is inserted into one of the two conductive wires that transport power supplied from the AC power source to the load. Two input ends of the filter circuit are connected to both ends of the AC power source, and two output ends of the filter circuit are connected to both ends of the primary winding of the transformer. In this line filter, a noise component is extracted from a power supply voltage by a filter circuit, and this noise component is supplied to the primary winding of the transformer, whereby the power supply voltage is applied on the conductive line in which the secondary winding of the transformer is inserted. The noise component is subtracted from. This line filter reduces normal mode noise.
[0007]
[Patent Document 1]
JP-A-9-102723
[0008]
[Problems to be solved by the invention]
Since the conventional LC filter has a specific resonance frequency determined by inductance and capacitance, there is a problem that a desired attenuation can be obtained only in a narrow frequency range.
[0009]
In addition, the filter inserted into the power transporting conductive wire is required to obtain desired characteristics in a state where a current for power transporting flows and to take measures against temperature rise. Therefore, such a filter has a problem that the inductance element is increased in size in order to realize desired characteristics.
[0010]
On the other hand, in the line filter described in Patent Document 1, if the impedance of the filter circuit is 0 and the coupling coefficient of the transformer is 1, theoretically, the noise component can be completely removed. However, in practice, the impedance of the filter circuit does not become zero, and further changes according to the frequency. In particular, when a filter circuit is constituted by a capacitor, a series resonance circuit is constituted by the capacitor and the primary winding of the transformer. Therefore, the impedance of the signal path including the capacitor and the primary winding of the transformer is reduced only in a narrow frequency range near the resonance frequency of the series resonance circuit. As a result, this line filter can remove noise components only in a narrow frequency range. Further, the coupling coefficient of the transformer is actually smaller than 1. Therefore, the noise component supplied to the primary winding of the transformer is not completely subtracted from the power supply voltage. For these reasons, the actually configured line filter has a problem that noise components cannot be effectively removed in a wide frequency range.
[0011]
In actual conductive lines, the ratio of normal mode noise to common mode noise varies, but normal mode noise and common mode noise are often mixed. Therefore, there is a need for a noise suppression circuit that can reduce both normal mode noise and common mode noise.
[0012]
A general EMI filter includes a filter for reducing normal mode noise and a filter for reducing common mode noise. For this reason, the EMI filter has the same problems as the LC filter described above, and has a problem that the number of parts is large and the size is increased.
[0013]
The present invention has been made in view of such problems, and an object of the present invention is to provide a noise suppression circuit that can suppress normal mode noise and common mode noise and can be miniaturized.
[0014]
[Means for Solving the Problems]
The first and second noise suppression circuits of the present invention include normal mode noise suppression means for suppressing normal mode noise that is transmitted by the first and second conductive lines and causes a potential difference between the conductive lines. Common mode noise suppression means for suppressing common mode noise propagating in the same phase through the first and second conductive lines.
[0015]
In the first noise suppression circuit of the present invention, the common mode noise suppression means includes a first winding inserted into the first conductive line at a predetermined first position, and a position corresponding to the first position. A second winding inserted into the second conductive line and coupled to the first winding to generate leakage inductance and cooperate with the first winding to suppress common mode noise; Have.
[0016]
In the first noise suppression circuit of the present invention, the normal mode noise suppression means is inserted into the first conductive line at a second position different from the first position, and normal mode noise on the first conductive line. A third winding for suppressing normal mode noise, a fourth winding inserted into the second conductive line at a position corresponding to the second position and suppressing normal mode noise on the second conductive line, A fifth winding coupled to the fourth winding, connected to the fifth winding, connected to the first conductive line at a third position different from the first and second positions, and Normal mode injection signal transmission for transmitting a normal mode injection signal that is connected to the second conductive line at a position corresponding to the third position and is injected into the first and second conductive lines to suppress normal mode noise. Road.
[0017]
Further, in the first noise suppression circuit of the present invention, the first position is disposed between the second position and the third position, and thereby the leakage inductance generated by the first and second windings. Thus, the peak value of the normal mode noise passing through the first and second conductive lines between the second position and the third position is reduced.
[0018]
In the first noise suppression circuit of the present invention, the source of normal mode noise is closer to the third position than the second position, except for the position between the second position and the third position. If so, the normal mode injection signal transmission path generates a normal mode injection signal based on signals detected from the first and second conductive lines at the third position and the corresponding position, This normal mode injection signal is supplied to the fifth winding. The fifth winding injects a normal mode injection signal into the first conductive line via the third winding so as to be in reverse phase to the normal mode noise on the first conductive line, and The normal mode injection signal is injected into the second conductive line through the winding 4 so as to be in reverse phase to the normal mode noise on the second conductive line. Thereby, in the first and second conductive lines, the normal mode noise is suppressed from the second position in the forward direction of the normal mode noise.
[0019]
In the first noise suppression circuit of the present invention, the source of normal mode noise is closer to the second position than the third position, except for the position between the second position and the third position. When in position, the fifth winding generates a normal mode injection signal based on signals detected from the first and second conductive lines at the second position and the corresponding position. The normal mode injection signal transmission line injects a normal mode injection signal into the first conductive line at the third position so as to have a phase opposite to the normal mode noise on the first conductive line, and the third mode. At a position corresponding to the position, a normal mode injection signal is injected into the second conductive line so as to be in opposite phase to the normal mode noise on the second conductive line. As a result, in the first and second conductive lines, the normal mode noise is suppressed from the third position in the forward direction of the normal mode noise.
[0020]
In the first noise suppression circuit of the present invention, the normal mode injection signal transmission path may include a capacitor for passing the normal mode injection signal.
[0021]
In the first noise suppression circuit of the present invention, the common mode noise suppression means is further connected to a sixth winding coupled to the first and second windings and to the sixth winding, In order to suppress common mode noise, the first conductive line is connected to the first conductive line at a fourth position different from the first position, and further connected to the second conductive line at a position corresponding to the fourth position. And a common mode injection signal transmission line for transmitting a common mode injection signal injected into the second conductive line, and inserted into the first conductive line at a fifth position between the first position and the fourth position. The seventh winding and the seventh winding are inserted into the second conductive wire at a position corresponding to the fifth position and are coupled to the seventh winding, and cooperate with the seventh winding to reduce common mode noise. You may have the 8th coil | winding to suppress. The seventh and eighth windings reduce the peak value of common mode noise passing through the first and second conductive lines between the first position and the fourth position.
[0022]
In the case where the first noise suppression circuit of the present invention has the above-described configuration, the common mode noise generation source is fourth than the first position except for the position between the first position and the fourth position. Common mode injection signal based on signals detected from the first and second conductive lines at the fourth position and the corresponding position by the common mode injection signal transmission line. And the common mode injection signal is supplied to the sixth winding. The sixth winding transmits the common mode injection signal through the first and second windings so that the common mode injection signal has a phase opposite to the common mode noise on the first and second conductive lines. Inject into the conductive wire. Thereby, in the first and second conductive lines, the common mode noise is suppressed from the first position in the traveling direction of the common mode noise.
[0023]
Further, in the case where the first noise suppression circuit of the present invention has the above-described configuration, the common mode noise source is more than the fourth position except for the position between the first position and the fourth position. When in a position close to the first position, the sixth winding causes the common mode injection based on signals detected from the first and second conductive lines at the first position and the corresponding position by the sixth winding. A signal is generated. The common mode injection signal transmission line transmits the common mode injection signal at the fourth position and the corresponding position so that the common mode injection signal has a phase opposite to the common mode noise on the first and second conductive lines. Inject into two conductive lines. Thereby, in the first and second conductive lines, the common mode noise is suppressed beyond the fourth position in the traveling direction of the common mode noise.
[0024]
In the case where the first noise suppression circuit of the present invention has the above-described configuration, the seventh winding and the eighth winding are coupled so that leakage inductance is generated, and the fifth position is the second position. It may be arranged between the position and the third position. Thereby, in addition to the leakage inductance generated by the first and second windings, the leakage inductance generated by the seventh and eighth windings also causes the first and second positions to be changed between the second position and the third position. The peak value of normal mode noise passing through the first and second conductive lines is reduced.
[0025]
In the first noise suppression circuit of the present invention, the common mode injection signal transmission path may include a capacitor for allowing the common mode injection signal to pass therethrough.
[0026]
In the second noise suppression circuit of the present invention, the normal mode noise suppression means is inserted into the first conductive line at a predetermined first position, and the first winding for suppressing normal mode noise on the first conductive line. The wire is inserted into the second conductive line at a position corresponding to the first position, and coupled to the first winding so as to generate a leakage inductance, thereby suppressing normal mode noise on the second conductive line. Second winding.
[0027]
In the second noise suppression circuit of the present invention, the common mode noise suppression means includes a third winding inserted in the first conductive line at a second position different from the first position, and a second winding. A fourth winding which is inserted into the second conductive line at a position corresponding to the position of the first winding and coupled to the third winding and which suppresses common mode noise in cooperation with the third winding; A fifth winding coupled to the third and fourth windings and a fifth winding connected to the fifth winding and connected to the first conductive line at a third position different from the first and second positions; Further, common mode injection is connected to the second conductive line at a position corresponding to the third position, and transmits a common mode injection signal injected into the first and second conductive lines to suppress common mode noise. Signal transmission path.
[0028]
Further, in the second noise suppression circuit of the present invention, the first position is disposed between the second position and the third position, and thereby the leakage inductance generated by the first and second windings. Thus, the peak value of the common mode noise passing through the first and second conductive lines between the second position and the third position is reduced.
[0029]
In the second noise suppression circuit of the present invention, the common mode noise source is closer to the third position than the second position, except for the position between the second position and the third position. If in position, the common mode injection signal transmission path generates a common mode injection signal based on signals detected from the first and second conductive lines at the third position and the corresponding position, This common mode injection signal is supplied to the fifth winding. The fifth winding transmits the common mode injection signal through the third and fourth windings so that the common mode injection signal has a phase opposite to the common mode noise on the first and second conductive lines. Inject into the conductive wire. Thereby, in the first and second conductive lines, the common mode noise is suppressed beyond the second position in the traveling direction of the common mode noise.
[0030]
In the second noise suppression circuit of the present invention, the common mode noise source is closer to the second position than the third position, except for a position between the second position and the third position. When in position, the fifth winding generates a common mode injection signal based on signals detected from the first and second conductive lines at the second position and the corresponding position. The common mode injection signal transmission path transmits the common mode injection signal to the first and second common modes so that the common mode injection signal has a phase opposite to the common mode noise on the first and second conductive lines at the third position and the corresponding position. Inject into two conductive lines. Thereby, in the first and second conductive lines, the common mode noise is suppressed beyond the third position in the traveling direction of the common mode noise.
[0031]
In the second noise suppression circuit of the present invention, the common mode injection signal transmission path may include a capacitor for passing the common mode injection signal.
[0032]
In the second noise suppression circuit of the present invention, the normal mode noise suppression means is further connected to a sixth winding coupled to the first and second windings and to the sixth winding, The first conductive line is connected to the first conductive line at a fourth position different from the first position, and further connected to the second conductive line at a position corresponding to the fourth position, so as to suppress normal mode noise. And a normal mode injection signal transmission path for transmitting a normal mode injection signal injected into the second conductive line. In this case, the second position is located between the first position and the fourth position, so that the leakage inductance generated by the third and fourth windings causes the first position and the fourth position. The peak value of normal mode noise passing through the first and second conductive lines between the positions may be reduced.
[0033]
In the case where the second noise suppression circuit according to the present invention has the above-described configuration, the source of the normal mode noise is fourth than the first position except for the position between the first position and the fourth position. The normal mode injection signal based on the signals detected from the first and second conductive lines at the fourth position and the corresponding position by the normal mode injection signal transmission line. This normal mode injection signal is supplied to the sixth winding. The sixth winding injects a normal mode injection signal into the first conductive line through the first winding so as to be in a phase opposite to the normal mode noise on the first conductive line, and A normal mode injection signal is injected into the second conductive line through the second winding so as to be in opposite phase to the normal mode noise on the second conductive line. Thereby, in the first and second conductive lines, the normal mode noise is suppressed beyond the first position in the traveling direction of the normal mode noise.
[0034]
In the case where the second noise suppression circuit of the present invention is configured as described above, the source of normal mode noise is first than the fourth position except for the position between the first position and the fourth position. The normal mode injection signal based on signals detected from the first and second conductive lines at the first position and the corresponding position by the sixth winding. Generated. The normal mode injection signal transmission line injects the normal mode injection signal into the first conductive line at the fourth position so as to be in reverse phase to the normal mode noise on the first conductive line, At a position corresponding to the position, a normal mode injection signal is injected into the second conductive line so as to be in opposite phase to the normal mode noise on the second conductive line. Thereby, in the first and second conductive lines, normal mode noise is suppressed beyond the fourth position in the traveling direction of normal mode noise.
[0035]
In the second noise suppression circuit of the present invention, the normal mode injection signal transmission path may include a capacitor for passing the normal mode injection signal.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, the noise suppression technique used in the embodiment of the present invention will be described. In the embodiment of the present invention, a cancellation type noise suppression circuit is used. With reference to FIG. 2, the basic configuration and operation of this canceling noise suppression circuit will be described.
[0037]
As shown in FIG. 2, the canceling noise suppression circuit is connected to the injection / detection unit 105 inserted into the conductive wire 101 at the predetermined position A, and is different from the position A. The injection signal transmission unit 106 connected to the conductive line 101 at the position B and the impedance element 107 inserted into the conductive line 101 between the position A and the position B are provided. The injection / detection unit 105 and the impedance element 107 each include, for example, an inductance element. Injection signal transmission unit 106 includes, for example, a high-pass filter made of a capacitor.
[0038]
In the cancellation type noise suppression circuit shown in FIG. 2, when the noise generation source is located at a position closer to the position B than the position A except for the position between the position A and the position B, the injection signal transmission unit 106 detects a signal corresponding to noise on the conductive line 101 at the position B, and generates an injection signal injected into the conductive line 101 to suppress noise on the conductive line 101 based on this signal. . The injection signal transmission unit 106 supplies this injection signal to the injection / detection unit 105. The injection / detection unit 105 injects an injection signal into the conductive line 101 so as to have a phase opposite to the noise on the conductive line 101. Thereby, the noise on the conductive line 101 is canceled by the injection signal, and the noise is suppressed in the conductive line 101 from the position A to the tip of the noise traveling direction. In the present application, noise includes unnecessary signals.
[0039]
Further, in the cancellation type noise suppression circuit shown in FIG. 2, when the noise generation source is located closer to the position A than the position B except for the position between the positions A and B, the injection / The detection unit 105 detects a signal corresponding to noise on the conductive wire 101. Based on the signal detected by the injection / detection unit 105, the injection signal transmission unit 106 generates an injection signal injected into the conductive line 101 in order to suppress noise on the conductive line 101. The injection signal transmission unit 106 injects an injection signal into the conductive line 101 at the position B so as to have a phase opposite to the noise on the conductive line 101. As a result, the noise on the conductive line 101 is canceled by the injection signal, and the noise is suppressed in the conductive line 101 from the position B to the tip of the noise traveling direction.
[0040]
In addition, the impedance element 107 reduces the peak value of noise passing through the conductive wire 101 between the position A and the position B. Thereby, the difference between the crest value of the noise propagating via the impedance element 107 and the crest value of the injection signal injected into the conductive wire 101 via the injection signal transmission unit 106 is reduced.
[0041]
As will be described in detail later, according to the cancellation type noise suppression circuit, it is possible to effectively suppress noise in a wide frequency range.
[0042]
Hereinafter, an example of a specific configuration of the canceling noise suppression circuit will be described. The configuration of the cancellation type noise suppression circuit includes a configuration for suppressing normal mode noise and a configuration for suppressing common mode noise.
[0043]
First, an example of the configuration of a canceling noise suppression circuit for suppressing normal mode noise will be described with reference to FIG. The canceling noise suppression circuit shown in FIG. 3 connects a pair of terminals 111a and 111b, another pair of terminals 112a and 112b, a conductive wire 113 connecting the terminals 111a and 112a, and the terminals 111b and 112b. And a conductive wire 114 to be provided. This canceling noise suppression circuit further includes, at a predetermined position A, a first winding 115a inserted into the conductive wire 113, a magnetic core 115c, and a first winding 115a via the magnetic core 115c. The second winding 115b is coupled. The windings 115a and 115b are both wound around the magnetic core 115c.
[0044]
The canceling noise suppression circuit shown in FIG. 3 further includes a capacitor 116 having one end connected to the conductive wire 113 at a position B different from the position A and the other end connected to one end of the second winding 115b. And an inductance element 117 inserted in the conductive wire 113 at a position between the position A and the position B. The other end of the second winding 115 b is connected to the conductive wire 114. The capacitor 116 functions as a high-pass filter that passes a signal having a frequency equal to or higher than a predetermined value.
[0045]
The windings 115a and 115b and the magnetic core 115c correspond to the injection / detection unit 105 in FIG. The capacitor 116 corresponds to the injection signal transmission unit 106 in FIG. The inductance element 117 corresponds to the impedance element 107 in FIG.
[0046]
Next, the operation of the cancellation type noise suppression circuit shown in FIG. 3 will be described. First, a case where the noise generation source is located at a position closer to the position B than the position A except for the position between the position A and the position B will be described. In this case, the capacitor 116 detects normal mode noise on the conductive line 113 at the position B, and further generates an injection signal having a phase opposite to the noise. This injection signal is supplied to the second winding 115b. The second winding 115b injects an injection signal into the conductive line 113 through the first winding 115a. As a result, normal mode noise is suppressed from the position A in the conductive line 113 in the direction of travel of the normal mode noise.
[0047]
Next, in the cancellation type noise suppression circuit shown in FIG. 3, a case where the noise generation source is located closer to the position A than the position B except for the position between the position A and the position B will be described. In this case, normal mode noise on the conductive line 113 at the position A is detected by the second winding 115b via the first winding 115a, and an injection signal corresponding to this normal mode noise is generated. The This injection signal is injected through the capacitor 116 so as to have an opposite phase to the normal mode noise on the conductive line 113 at the position B. As a result, normal mode noise is suppressed from the position B in the conductive line 113 beyond the normal mode noise traveling direction.
[0048]
Here, consider a circuit obtained by removing the inductance element 117 from the canceling noise suppression circuit shown in FIG. Here, it is assumed that the impedance of the capacitor 116 is 0 and the coupling coefficient between the first winding 115a and the second winding 115b is 1. Here, consider the case where the source of normal mode noise is located closer to position B than position A, and normal mode noise that causes a potential difference Vin between terminals 111a and 111b is input to terminals 111a and 111b. . In this case, the normal mode noise passes through the capacitor 116, and at that time, the phase is shifted by 180 ° by the action of the capacitor 116. As a result, a potential difference −Vin is generated between both ends of the second winding 115b. In response to the potential difference −Vin generated between both ends of the second winding 115b, a potential difference −Vin is also generated between both ends of the first winding 115a. As a result, the potential difference between the terminals 112a and 112b becomes zero. Therefore, according to the canceling noise suppression circuit, in principle, it is possible to completely remove normal mode noise in the pass band of the capacitor 116 regardless of the frequency. That is, according to the cancellation type noise suppression circuit, it is possible to effectively suppress normal mode noise in a wide frequency range.
[0049]
However, in practice, the impedance of the capacitor 116 does not become zero, and further changes according to the frequency. Since the series resonance circuit is configured by the capacitor 116 and the second winding 115b, the impedance of the signal path including the capacitor 116 and the second winding 115b is near the resonance frequency of the series resonance circuit. It becomes small only in a narrow frequency range. Therefore, the canceling noise suppression circuit that does not include the inductance element 117 can reduce normal mode noise only in a narrow frequency range. Further, the coupling coefficient between the first winding 115a and the second winding 115a is actually smaller than 1. Therefore, a voltage having the same value as the voltage supplied to the second winding 115b is not generated in the first winding 115a. For these reasons, it is difficult to effectively suppress normal mode noise in a wide frequency range in a cancellation noise suppression circuit that does not include the inductance element 117.
[0050]
In the cancellation type noise suppression circuit shown in FIG. 3, the inductance element 117 is inserted into the conductive wire 113 between the position A and the position B. Thus, in this canceling noise suppression circuit, the difference between the peak value of normal mode noise propagating through the inductance element 117 and the peak value of the reverse-phase signal injected into the conductive wire 113 via the capacitor 116. Is reduced. As a result, according to the canceling noise suppression circuit, it is possible to effectively suppress normal mode noise in a wide frequency range.
[0051]
Next, the operation of the canceling noise suppression circuit shown in FIG. 3 will be described in detail with reference to FIG. FIG. 4 is a circuit diagram showing a circuit in which a normal mode noise source 118 and a load 119 are connected to the canceling noise suppression circuit shown in FIG. The normal mode noise generation source 118 is connected between the terminals 111a and 111b, and generates a potential difference Vin between the terminals 111a and 111b. The load 119 is connected between the terminals 112a and 112b and has an impedance Zo.
[0052]
In the circuit shown in FIG. 4, the inductance of the second winding 115b is L11, the inductance of the first winding 115a is L12, the capacitance of the capacitor 116 is C1, and the inductance of the inductance element 117 is L21. Further, the current passing through the capacitor 116 and the second winding 115b is i1, and the total impedance of the path of the current i1 is Z1. Further, the current passing through the inductance element 117 and the first winding 115a is i2, and the total impedance of the path of the current i2 is Z2.
[0053]
Further, let M be the mutual inductance between the first winding 115a and the second winding 115b, and K be the coupling coefficient between them. The coupling coefficient K is expressed by the following formula (1).
[0054]
K = M / √ (L11 · L12) (1)
[0055]
The total impedances Z1 and Z2 of the above impedance are expressed by the following equations (2) and (3), respectively. Note that j represents √ (−1), and ω represents the angular frequency of normal mode noise.
[0056]
Z1 = j (ωL11-1 / ωC1) (2)
Z2 = Zo + jω (L12 + L21) (3)
[0057]
The potential difference Vin is expressed by the following equations (4) and (5).
[0058]
Vin = Z1 · i1 + jωM · i2 (4)
Vin = Z2 · i2 + jωM · i1 (5)
[0059]
Hereinafter, an expression representing the current i2 is obtained without including the current i1 based on the expressions (2) to (5). For this purpose, first, the following equation (6) is derived from the equation (4).
[0060]
i1 = (Vin−jωM · i2) / Z1 (6)
[0061]
Next, when Expression (6) is substituted into Expression (5), the following Expression (7) is obtained.
[0062]
i2 = Vin (Z1-jωM) / (Z1 · Z2 + ω ² ・ M ² (7)
[0063]
It can be said that suppressing the normal mode noise by the canceling noise suppression circuit shown in FIG. 4 is reducing the current i2 expressed by the equation (7). According to equation (7), the current i2 decreases as the denominator on the right side of equation (7) increases. Therefore, the denominator (Z1 · Z2 + ω on the right side of equation (7) ² ・ M ² ).
[0064]
First, since Z1 is expressed by Expression (2), it increases as the inductance L11 of the second winding 115b increases, and increases as the capacitance C1 of the capacitor 116 increases.
[0065]
Next, since Z2 is expressed by Expression (3), it increases as the sum of the inductance L12 of the first winding 115a and the inductance L21 of the inductance element 117 increases. Therefore, if at least one of the inductance L12 and the inductance L21 is increased, the current i2 can be decreased. In addition, it can be seen from Equation (7) that normal mode noise can be suppressed only by the first winding 115a, but normal mode noise can be further suppressed by adding the inductance element 117.
[0066]
The denominator on the right side of equation (7) is ω ² ・ M ² Therefore, the current i2 can be reduced by increasing the mutual inductance M. As can be seen from Equation (1), the coupling coefficient K is proportional to the mutual inductance M. Therefore, if the coupling coefficient K is increased, the effect of suppressing normal mode noise by the canceling noise suppression circuit shown in FIG. Since the mutual inductance M is included in the form of a square in the denominator on the right side of Equation (7), the effect of suppressing normal mode noise greatly varies depending on the value of the coupling coefficient K.
[0067]
When the source of normal mode noise is located closer to position A than position B, the roles of second winding 115b and capacitor 116 are opposite to those described with reference to FIGS. become. However, in this case as well, the above description applies as well.
[0068]
Next, an example of the configuration of a cancellation type noise suppression circuit for suppressing common mode noise will be described with reference to FIG. The canceling noise suppression circuit shown in FIG. 5 connects a pair of terminals 121a and 121b, another pair of terminals 122a and 122b, a conductive wire 123 connecting the terminals 121a and 122a, and the terminals 121b and 122b. And a conductive wire 124 to be provided. This canceling noise suppression circuit is further inserted into the conductive wire 124 at a position corresponding to the first winding 125a and the magnetic core 125d inserted into the conductive wire 123 at a predetermined position A. In addition, the second winding 125b is coupled to the first winding 125a via the magnetic core 125d and suppresses common mode noise in cooperation with the first winding 125a, and the first winding via the magnetic core 125d. And a third winding 125c coupled to the second winding 125b. The windings 125a and 125b and the magnetic core 125d constitute a common mode choke coil. That is, the windings 125a and 125b are oriented so that the magnetic fluxes induced in the magnetic core 125d are offset by the currents flowing through the windings 125a and 125b when the normal mode current flows through the windings 125a and 125b. It is wound around the magnetic core 125d. Thus, the windings 125a and 125b suppress common mode noise and allow normal mode noise to pass.
[0069]
5 further includes a capacitor 126a having one end connected to the conductive line 123 at a position B different from the position A and the other end connected to one end of the third winding 125c. And a capacitor 126b having one end connected to the conductive wire 124 at a position corresponding to the position B and the other end connected to one end of the third winding 125c. The other end of the third winding 125c is grounded. Capacitors 126a and 126b function as high-pass filters that allow signals having a frequency equal to or higher than a predetermined value to pass.
[0070]
The canceling noise suppression circuit shown in FIG. 5 is further conductive at a position corresponding to the position C, the winding 127a inserted into the conductive wire 123 at the position C between the position A and the position B, and the magnetic core 127c. A winding 127b that is inserted into the wire 124 and coupled to the winding 127a via the magnetic core 127c and suppresses common mode noise in cooperation with the winding 127a is provided. The windings 127a and 127b and the magnetic core 127c constitute a common mode choke coil. That is, the windings 127a and 127b are oriented so that the magnetic fluxes induced in the magnetic core 127c are canceled by the currents flowing through the windings 127a and 127b when the normal mode current flows through the windings 127a and 127b. It is wound around the magnetic core 127c. Thus, the windings 127a and 127b suppress common mode noise and allow normal mode noise to pass.
[0071]
The windings 125a, 125b, 125c and the magnetic core 125d correspond to the injection / detection unit 105 in FIG. The capacitors 126a and 126b correspond to the injection signal transmission unit 106 in FIG. The common mode choke coil including the windings 127a and 127b and the magnetic core 127c corresponds to the impedance element 107 in FIG.
[0072]
The operation of the cancellation type noise suppression circuit shown in FIG. 5 will be described. First, a case where the noise generation source is located at a position closer to the position B than the position A except for the position between the position A and the position B will be described. In this case, common mode noise on the conductive lines 123 and 124 at the position B and the corresponding position is detected by the capacitors 126a and 126b, and an injection signal having a phase opposite to that of the noise is generated. The This injection signal is supplied to the third winding 125c. The third winding 125c injects an injection signal into the conductive lines 123 and 124 via the first and second windings 125a and 125b. As a result, the common mode noise is suppressed in the conductive lines 123 and 124 from the position A beyond the traveling direction of the common mode noise.
[0073]
Further, in the cancellation type noise suppression circuit shown in FIG. 5, when the noise generation source is located closer to the position A than the position B except for the position between the position A and the position B, the first In addition, the third winding 125c via the second windings 125a and 125b detects the common mode noise on the conductive lines 123 and 124 at the position A and the corresponding position, and the common mode noise corresponds to the common mode noise. An injection signal is generated. This injection signal is injected through the capacitors 126a and 126b so as to have an opposite phase to the common mode noise on the conductive lines 123 and 124 at the position B and the position corresponding thereto. Thereby, in the conductive lines 113 and 114, the common mode noise is suppressed from the position B in the forward direction of the common mode noise.
[0074]
In the canceling noise suppression circuit shown in FIG. 5, the action of the canceling noise suppression circuit shown in FIG. 3 is considered when the action related to the noise on the conductive line 123 is divided into the action related to the noise on the conductive line 124. This detailed description also applies to the cancellation type noise suppression circuit shown in FIG.
[0075]
In the embodiment of the present invention, a noise filter circuit including two windings coupled so as to generate a leakage inductance is used in addition to the cancellation type noise suppression circuit described so far. This noise filter circuit includes a common mode noise filter circuit that suppresses common mode noise and a normal mode noise filter circuit that suppresses normal mode noise. Hereinafter, these noise filter circuits will be described.
[0076]
FIG. 6 is a circuit diagram showing a common mode noise filter circuit. This filter circuit includes a pair of terminals 131a and 131b, another pair of terminals 132a and 132b, a conductive line 133 that connects the terminals 131a and 132a, and a conductive line 134 that connects the terminals 131b and 132b. ing. The filter circuit is further coupled to the first winding 135a through the magnetic core 135c and the first winding 135a inserted into the conductive wire 133, the magnetic core 135c, and the conductive wire 134. And a second winding 135b for suppressing common mode noise in cooperation with the first winding 135a. The windings 135a and 135b are arranged in such a direction that magnetic fluxes induced in the magnetic core 135c are canceled by the currents flowing through the windings 135a and 135b when a normal mode current flows through the windings 135a and 135b. It is wound around the core 135c. Thus, the windings 135a and 135b suppress common mode noise and allow normal mode noise to pass.
[0077]
In the filter circuit shown in FIG. 6, the coupling coefficient between the winding 135 a and the winding 135 b is smaller than 1. Therefore, the windings 135a and 135b generate leakage inductance in the conductive wires 133 and 134, respectively. Considering these leakage inductances, an equivalent circuit of the filter circuit shown in FIG. 6 is as shown in FIG. In the circuit shown in FIG. 7, a virtual inductor 136a having an inductance equal to the leakage inductance on the conductive wire 133 side is inserted between the winding 135a and the terminal 132a in the circuit shown in FIG. And a terminal 132b, a virtual inductor 136b having an inductance equal to the leakage inductance on the conductive wire 134 side is inserted.
[0078]
Here, in the circuit shown in FIG. 7, for example, the inductances of the windings 135a and 135b are each 300 μH, and the coupling coefficient between the windings 135a and 135b is 0.995, which is a generally obtained value. To do. In this case, the leakage inductance in each of the conductive wires 133 and 134, that is, the inductance of the inductors 136a and 136b is 1.5 μH.
[0079]
FIG. 8 is a circuit diagram showing a normal mode noise filter circuit. This filter circuit includes a pair of terminals 141a and 141b, another pair of terminals 142a and 142b, a conductive wire 143 connecting the terminals 141a and 142a, and a conductive wire 144 connecting the terminals 141b and 142b. ing. This filter circuit is further inserted into the conductive wire 143 to suppress the normal mode noise on the conductive wire 143, the magnetic core 145c, the conductive wire 144 and the magnetic core 145c. And a second winding 145 b that is coupled to the first winding 145 a and suppresses normal mode noise on the conductive wire 144. The windings 145a and 145b are oriented so that the directions of magnetic fluxes induced in the magnetic core 145c by the current flowing through the windings 145a and 145b when the normal mode current flows through the windings 145a and 145b are the same. It is wound around the magnetic core 145c. Thereby, the windings 145a and 145b suppress the normal mode noise and allow the common mode noise to pass.
[0080]
In the filter circuit shown in FIG. 8, the coupling coefficient between the winding 145 a and the winding 145 b is smaller than 1. Accordingly, the windings 145a and 145b generate leakage inductance in the conductive wires 143 and 144, respectively. Considering these leakage inductances, an equivalent circuit of the filter circuit shown in FIG. 8 is as shown in FIG. In the circuit shown in FIG. 9, in the circuit shown in FIG. 8, a virtual inductor 146a having an inductance equal to the leakage inductance on the conductive wire 143 side is inserted between the winding 145a and the terminal 142a, and the winding 145b. And a terminal 142b, a virtual inductor 146b having an inductance equal to the leakage inductance on the conductive wire 144 side is inserted.
[0081]
Each embodiment of the present invention effectively suppresses normal mode noise and common mode noise in a wide frequency range by using the noise suppression technology described with reference to FIGS. 2 to 9 and using leakage inductance. A noise suppression circuit that can be reduced in size is realized.
[0082]
[First Embodiment]
FIG. 1 is a circuit diagram showing a configuration of a noise suppression circuit according to the first embodiment of the present invention. The noise suppression circuit according to the present embodiment has both the function of the cancellation type noise suppression circuit for suppressing normal mode noise shown in FIG. 3 and the function of the common mode noise filter circuit shown in FIG.
[0083]
The noise suppression circuit according to the present embodiment includes a pair of terminals 1a and 1b, another pair of terminals 2a and 2b, a first conductive line 3 connecting the terminals 1a and 2a, and the terminals 1b and 2b. And a second conductive wire 4 for connecting the two. The noise suppression circuit is connected to a power line that transports AC power or DC power. The power line includes two power conductive lines. The noise suppression circuit is inserted in the middle of the two power conductive lines. Terminals 1a and 2a are connected to one power conductive line, and terminals 1b and 2b are connected to the other power conductive line. Noise sources to be suppressed by the noise suppression circuit are connected to the terminals 1a and 1b or the terminals 2a and 2b. Therefore, the noise to be suppressed is input to the noise suppression circuit from the terminals 1a and 1b or the terminals 2a and 2b.
[0084]
The noise suppression circuit is further connected to the conductive wire 4 at the first winding W11 inserted into the conductive wire 3 at the predetermined first position P11a, the magnetic core 11, and the position P11b corresponding to the first position P11a. A second winding that is inserted and coupled to the first winding W11 via the magnetic core 11 so as to generate a leakage inductance, and suppresses common mode noise in cooperation with the first winding W11. W12. The windings W11 and W12 and the magnetic core 11 constitute a common mode choke coil. That is, the windings W11 and W12 are oriented so that the magnetic fluxes induced in the magnetic core 11 are offset by the currents flowing through the windings W11 and W12 when a normal mode current flows through the windings W11 and W12. It is wound around the magnetic core 11. Thus, the windings W11 and W12 suppress common mode noise and allow normal mode noise to pass. For example, the winding numbers of the windings W11 and W12 are equal. The windings W11 and W12 and the magnetic core 11 correspond to the common mode noise suppression means in the present invention, and exhibit the function of the common mode noise filter circuit shown in FIG.
[0085]
The noise suppression circuit is further inserted into the conductive wire 3 at a second position P12a different from the first position P11a, and a third winding W13 for suppressing normal mode noise on the conductive wire 3, and the magnetic core 12 Are inserted into the conductive wire 4 at a position P12b corresponding to the second position P12a and are coupled to the third winding W13 via the magnetic core 12 to suppress normal mode noise on the conductive wire 4. Winding W14, and a fifth winding W15 coupled to the third winding W13 and the fourth winding W14 via the magnetic core 12. The windings W13 and W14 are oriented so that the directions of magnetic fluxes induced in the magnetic core 12 by the current flowing through the windings W13 and W14 when the normal mode current flows through the windings W13 and W14 are the same. It is wound around the magnetic core 12. As a result, the windings W13 and W14 suppress normal mode noise and allow common mode noise to pass. For example, the ratio of the number of turns of the windings W13, W14, W15 is 1: 1: 2.
[0086]
The noise suppression circuit further has one end connected to the conductive wire 3 at a third position P13a different from the first position P11a and the second position P12a, and the other end connected to one end of the fifth winding W15. The capacitor 13 is provided. The other end of the fifth winding W15 is connected to the conductive line 4 at a position P13b corresponding to the third position P13a. The capacitor 13 functions as a high-pass filter that passes a normal mode signal having a frequency equal to or higher than a predetermined value. A signal path from the position P13a through the capacitor 13 and the fifth winding W15 to the position P13b corresponds to the normal mode injection signal transmission path in the present invention. That is, this path transmits a normal mode injection signal injected into the conductive lines 3 and 4 in order to suppress normal mode noise.
[0087]
In the present embodiment, the coupling coefficient between the first winding W11 and the second winding W12 is smaller than 1. Therefore, the windings W11 and W12 generate a leakage inductance in each of the conductive wires 3 and 4. FIG. 1 includes virtual inductors L101 and L102 having inductances equal to these leakage inductances. The inductor L101 is inserted into the conductive wire 3 at a position between the first winding W11 and the third winding W13. The inductor L102 is inserted into the conductive wire 4 at a position between the second winding W12 and the fourth winding W14.
[0088]
In the present embodiment, the first position P11a is disposed between the second position P12a and the third position P13a. Thereby, the peak value of the normal mode noise passing through the conductive wires 3 and 4 between the positions P12a and P12b and the positions P13a and P13b is caused by the leakage inductance (inductors L101 and L102) generated by the windings W11 and W12. Reduced.
[0089]
The windings W13, W14, W15, the magnetic core 12, the capacitor 13, and the inductors L101, L102 correspond to the normal mode noise suppression means in the present invention, and exhibit the function of the cancellation type noise suppression circuit shown in FIG.
[0090]
Next, the operation of the noise suppression circuit according to the present embodiment will be described. First, the common mode noise suppression action of the noise suppression circuit will be described. Except for the position between the positions P12a and P12b and the positions P13a and P13b, the common mode noise source is located closer to the positions P13a and P13b than the positions P12a and P12b, and the common mode noise source is The common mode noise forms a common mode choke coil in any of the cases where the positions P12a and P13b are closer to the positions P12a and P12b, except for the positions between the positions P12a and P12b and the positions P13a and P13b. The windings W11 and W12 and the magnetic core 11 are suppressed.
[0091]
Next, the normal mode noise is generated when the source of the normal mode noise is located closer to the positions P13a and P13b than the positions P12a and P12b, except for the position between the positions P12a and P12b and the positions P13a and P13b. The mode noise suppressing action will be described. In this case, the signal corresponding to the normal mode noise is detected from the conductive lines 3 and 4 at the positions P13a and P13b by the capacitor 13, and based on this signal, the normal phase having a phase opposite to the normal mode noise is detected. A mode injection signal is generated. This normal mode injection signal is supplied to the fifth winding W15. The fifth winding W15 injects a normal mode injection signal into the conductive line 3 through the third winding W13 so as to be in opposite phase to the normal mode noise on the conductive line 3. Further, the fifth winding W15 injects a normal mode injection signal into the conductive line 4 through the fourth winding W14 so as to have a phase opposite to the normal mode noise on the conductive line 4. Thereby, the normal mode noise is suppressed in the conductive lines 3 and 4 from the positions P12a and P12b in the forward direction of the normal mode noise.
[0092]
Next, the normal mode noise is generated when the source of the normal mode noise is located closer to the positions P12a and P12b than the positions P13a and P13b except for the position between the positions P12a and P12b and the positions P13a and P13b. The mode noise suppressing action will be described. In this case, a signal corresponding to normal mode noise passing through the third winding W13 and the fourth winding W14 is induced in the fifth winding W15. In this manner, the fifth winding W15 detects a signal corresponding to normal mode noise from the conductive lines 3 and 4 at the positions P12a and P12b, and a normal mode injection signal corresponding to this signal is generated. . The normal mode injection signal passes through the capacitor 13 and is injected into the conductive lines 3 and 4 at the positions P13a and 13b. At the position P13a, a normal mode injection signal is injected into the conductive line 3 so as to have an opposite phase to the normal mode noise on the conductive line 3. At the position P13b, a normal mode injection signal is injected into the conductive line 4 so as to be in opposite phase to the normal mode noise on the conductive line 4. As a result, normal mode noise is suppressed from the positions P13a and P13b in the direction of travel of normal mode noise in the conductive lines 3 and 4.
[0093]
Thus, according to the noise suppression circuit according to the present embodiment, normal mode noise and common mode noise can be suppressed. In particular, the noise suppression circuit according to the present embodiment has the function of a canceling noise suppression circuit for suppressing normal mode noise. Therefore, according to this noise suppression circuit, it is possible to effectively suppress normal mode noise in a wide frequency range by taking advantage of the cancellation type noise suppression circuit.
[0094]
By the way, it is conceivable to construct a circuit capable of suppressing normal mode noise and common mode noise by simply combining a cancellation mode noise suppression circuit for suppressing normal mode noise and a common mode noise filter circuit. However, in this case, there is a problem that the number of parts included in the circuit increases and the circuit becomes large.
[0095]
In the present embodiment, the conductive wires 3 and 4 are provided with windings W11 and W12 coupled so as to generate leakage inductance between the positions P12a and P12b and the positions P13a and P13b. Then, due to the leakage inductance (inductors L101 and L102) generated by the windings W11 and W12, the peak value of the normal mode noise passing through the conductive lines 3 and 4 between the positions P12a and P12b and the positions P13a and P13b is obtained. Reduced. Thereby, between the positions P12a and P12b and the positions P13a and P13b, the peak value of the normal mode noise passing through the conductive lines 3 and 4, the conductive line 3 via the capacitor 13 and the fifth winding W15. The difference from the peak value of the injection signal injected into 4 is reduced.
[0096]
As described above, in the present embodiment, the conductive wires 3 and 4 are provided between the positions P12a and P12b and the positions P13a and P13b by using the leakage inductance generated by the windings W11 and W12 for suppressing the common mode noise. The peak value of normal mode noise that passes through is reduced. Therefore, in this embodiment, an inductance element for reducing the peak value of normal mode noise, such as the inductance element 117 in FIG. Therefore, according to the noise suppression circuit according to the present embodiment, the number of components is reduced as compared with a circuit configured by simply combining a cancellation noise suppression circuit for suppressing normal mode noise and a common mode noise filter circuit. Thus, the circuit can be reduced in size.
[0097]
In the present embodiment, the coupling coefficient of the windings W11 and W12 may be in the range of 0.001 to 0.999. The coupling coefficient is preferably set as appropriate according to the ratio of normal mode noise and common mode noise in an environment where the noise suppression circuit is used. In an environment where both normal mode noise and common mode noise exist to some extent, the coupling coefficient is preferably in the range of 0.2 to 0.8. In an environment where normal mode noise and common mode noise are present to the same extent, the coupling coefficient is preferably in the range of 0.4 to 0.6.
[0098]
In the present embodiment, the transmission path of the normal mode injection signal includes the capacitor 13 as an element for allowing the injection signal to pass. Therefore, according to the present embodiment, detection of a signal corresponding to normal mode noise and generation of an injection signal having a phase opposite to that of normal mode noise can be performed using only capacitor 13. Therefore, according to the present embodiment, the number of parts can be reduced.
[0099]
Next, an example of transmission characteristics of the noise suppression circuit according to the present embodiment will be described with reference to FIG. Here, each of the noise suppression circuit according to the present embodiment shown in FIG. 1, the cancellation type noise suppression circuit for normal mode noise suppression shown in FIG. 3, and the common mode noise filter circuit shown in FIG. The transmission characteristics were obtained by simulation. As the transmission characteristic, the frequency characteristic of gain was obtained.
[0100]
In this simulation, the following numerical values were used. First, the inductances of the windings W11 and W12 in FIG. 1 are both 300 μH, and their coupling coefficient is 0.995. Further, the inductances of the windings W13 and W14 in FIG. 1 are 60 μH, the inductance of the winding W15 is 240 μH, and the coupling coefficient of the windings W13, W14, and W15 is 0.8. Further, the capacitance of the capacitor 13 in FIG. 1 was set to 0.1 μF. Further, the inductances of the windings 115a and 115b in FIG. 3 are both 120 μH, and their coupling coefficient is 0.8. Further, the inductance of the inductance element 117 in FIG. 3 is 3 μH, and the capacitance of the capacitor 116 is 0.1 μF. Further, the inductances of the windings 135a and 135b in FIG. 6 are both 300 μH, and their coupling coefficient is 0.995.
[0101]
The transmission characteristics obtained by the above simulation are shown in FIG. In FIG. 10, the line indicated by reference numeral 15 represents the transmission characteristic for the common mode signal of the noise suppression circuit according to the present embodiment and the transmission characteristic for the common mode signal of the common mode noise filter circuit shown in FIG. 6. Yes. The two transmission characteristics represented by the line indicated by reference numeral 15 are completely matched. In FIG. 10, the line indicated by reference numeral 16 represents the transmission characteristics for the normal mode signal of the noise suppression circuit according to the present embodiment, and the line indicated by reference numeral 17 represents the cancellation type noise suppression shown in FIG. The transmission characteristic with respect to the normal mode signal of a circuit is represented. The two transmission characteristics represented by the lines 16 and 17 are almost the same. From FIG. 10, it can be seen that the noise suppression circuit according to the present embodiment exhibits the function of the cancellation noise suppression circuit shown in FIG. 3 and the function of the common mode noise filter circuit shown in FIG.
[0102]
[Second Embodiment]
FIG. 11 is a circuit diagram showing a configuration of a noise suppression circuit according to the second embodiment of the present invention. The noise suppression circuit according to the present embodiment has both the function of the cancellation type noise suppression circuit for common mode noise suppression shown in FIG. 5 and the function of the normal mode noise filter circuit shown in FIG.
[0103]
As in the first embodiment, the noise suppression circuit according to the present embodiment is a first pair that connects a pair of terminals 1a and 1b, another pair of terminals 2a and 2b, and the terminals 1a and 2a. A conductive line 3 and a second conductive line 4 connecting the terminals 1b and 2b are provided.
[0104]
The noise suppression circuit is further inserted into the conductive wire 3 at a predetermined first position P21a, and suppresses normal mode noise on the conductive wire 3, a first winding W21, a magnetic core 21, and a first position. It is inserted into the conductive wire 4 at a position P21b corresponding to P21a and is coupled to the first winding W21 via the magnetic core 21 so as to generate leakage inductance, thereby suppressing normal mode noise on the conductive wire 4. And a second winding W22. The windings W21 and W22 are oriented so that the directions of magnetic fluxes induced in the magnetic core 21 by the currents flowing through the windings W21 and W22 are the same when a normal mode current flows through the windings W21 and W22. It is wound around the magnetic core 21. As a result, the windings W21 and W22 suppress normal mode noise and allow common mode noise to pass. For example, the winding numbers of the windings W21 and W22 are equal. The windings W21 and W22 and the magnetic core 21 correspond to the normal mode noise suppressing means in the present invention and exhibit the function of the normal mode noise filter circuit shown in FIG.
[0105]
The noise suppression circuit further includes a third winding W23 inserted into the conductive wire 3 at a second position P22a different from the first position P21a, a magnetic core 22, and a position corresponding to the second position P22a. A fourth winding W24 inserted into the conductive wire 4 at P22b and coupled to the third winding W23 via the magnetic core 22 to suppress common mode noise in cooperation with the third winding W23; And a fifth winding W25 coupled to the third winding W23 and the fourth winding W24 via the magnetic core 22. The windings W23 and W24 and the magnetic core 22 constitute a common mode choke coil. That is, the windings W23 and W24 are oriented so that the magnetic fluxes induced in the magnetic core 22 are offset by the currents flowing through the windings W23 and W24 when the normal mode current flows through the windings W23 and W24. It is wound around the magnetic core 22. Thus, the windings W23 and W24 suppress common mode noise and allow normal mode noise to pass. For example, the winding numbers of the windings W23, W24, W25 are equal.
[0106]
The noise suppression circuit further has one end connected to the conductive wire 3 at a third position P23a different from the first position P21a and the second position P22a, and the other end connected to one end of the fifth winding W25. The capacitor 23 and one end connected to the conductive line 4 at a position P23b corresponding to the third position P23a, and the other end connected to the other end of the capacitor 23 and one end of the fifth winding W25. And. The other end of the fifth winding W25 is grounded. Capacitors 23 and 24 function as a high-pass filter that passes a common mode signal having a frequency equal to or higher than a predetermined value. A signal path from the positions P23a and P23b to the ground through the capacitors 23 and 24 and the fifth winding W25 corresponds to the common mode injection signal transmission path in the present invention. That is, this path transmits a common mode injection signal injected into the conductive lines 3 and 4 in order to suppress common mode noise.
[0107]
In the present embodiment, the coupling coefficient between the first winding W21 and the second winding W22 is smaller than one. Therefore, the windings W21 and W22 generate a leakage inductance in each of the conductive wires 3 and 4. FIG. 11 includes virtual inductors L201 and L202 having inductances equal to these leakage inductances. The inductor L201 is inserted into the conductive wire 3 at a position between the first winding W21 and the third winding W23. The inductor L202 is inserted into the conductive wire 4 at a position between the second winding W22 and the fourth winding W24.
[0108]
In the present embodiment, the first position P21a is disposed between the second position P22a and the third position P23a. Thereby, the peak value of the common mode noise passing through the conductive wires 3 and 4 between the positions P22a and P22b and the positions P23a and P23b is caused by the leakage inductance (inductors L201 and L202) generated by the windings W21 and W22. Reduced.
[0109]
The windings W23, W24, W25, the magnetic core 22, the capacitors 23, 24, and the inductors L201, L202 correspond to the common mode noise suppression means in the present invention and exhibit the function of the cancellation type noise suppression circuit shown in FIG. To do.
[0110]
Next, the operation of the noise suppression circuit according to the present embodiment will be described. First, the normal mode noise suppression action of the noise suppression circuit will be described. Except for the position between the positions P22a and P22b and the positions P23a and P23b, the normal mode noise is generated at a position closer to the positions P23a and P23b than the positions P22a and P22b. The normal mode noise is suppressed by the windings W21 and W22 in any case where the positions P22a and P23b are closer to the positions P22a and P22b than the positions P23a and P23b, except for the positions between the positions P22a and P22b and the positions P23a and P23b. Is done.
[0111]
Next, the common mode noise is generated when the common mode noise source is located closer to the positions P23a and P23b than the positions P22a and P22b except for the position between the positions P22a and P22b and the positions P23a and P23b. The mode noise suppressing action will be described. In this case, a signal corresponding to the common mode noise is detected by the capacitors 23 and 24 from the conductive lines 3 and 4 at the positions P23a and P23b. A common mode injection signal is generated. This common mode injection signal is supplied to the fifth winding W25. The fifth winding W25 conducts the common mode injection signal through the third winding W23 and the fourth winding W24 so as to be in opposite phase to the common mode noise on the conductive lines 3 and 4. Inject on lines 3 and 4. As a result, common mode noise is suppressed from the positions P22a and P22b in the direction of travel of the common mode noise in the conductive lines 3 and 4.
[0112]
Next, the common mode noise is generated when the common mode noise source is located closer to the positions P22a and P22b than the positions P23a and P23b, except for the position between the positions P22a and P22b and the positions P23a and P23b. The mode noise suppressing action will be described. In this case, a signal corresponding to the common mode noise passing through the third winding W23 and the fourth winding W24 is induced in the fifth winding W25. In this way, the fifth winding W25 detects a signal corresponding to the common mode noise from the conductive lines 3 and 4 at the positions P22a and P22b, and generates a common mode injection signal corresponding to this signal. . The common mode injection signal passes through the capacitors 23 and 24 and is injected into the conductive lines 3 and 4 at the positions P23a and P23b. The common mode injection signal is injected into the conductive lines 3 and 4 so as to have an opposite phase to the common mode noise on the conductive lines 3 and 4. As a result, common mode noise is suppressed from the positions P23a and P23b in the direction of travel of the common mode noise in the conductive lines 3 and 4.
[0113]
Thus, according to the noise suppression circuit according to the present embodiment, normal mode noise and common mode noise can be suppressed. In particular, the noise suppression circuit according to the present embodiment has a function of a canceling noise suppression circuit for common mode noise suppression. Therefore, according to this noise suppression circuit, it is possible to effectively suppress common mode noise in a wide frequency range by taking advantage of the cancellation type noise suppression circuit.
[0114]
By the way, it is also conceivable to construct a circuit capable of suppressing normal mode noise and common mode noise by simply combining a cancellation mode noise suppression circuit for suppressing common mode noise and a normal mode noise filter circuit. However, in this case, there is a problem that the number of parts included in the circuit increases and the circuit becomes large.
[0115]
In the present embodiment, the conductive wires 3 and 4 are provided with windings W21 and W22 that are coupled so as to generate leakage inductance between the positions P22a and P22b and the positions P23a and P23b. Due to the leakage inductance (inductors L201 and L202) generated by the windings W21 and W22, the peak value of the common mode noise passing through the conductive lines 3 and 4 between the positions P22a and P22b and the positions P23a and P23b is obtained. Reduced. Thereby, between the positions P22a and P22b and the positions P23a and P23b, the peak value of the common mode noise passing through the conductive lines 3 and 4, and the conductive lines via the capacitors 23 and 24 and the fifth winding W25. The difference with the peak value of the injection signal injected into 3 and 4 is reduced.
[0116]
As described above, in the present embodiment, the conductive wires 3 and 4 are provided between the positions P22a and P22b and the positions P23a and P23b by using the leakage inductance generated by the windings W21 and W22 for suppressing normal mode noise. The peak value of common mode noise that passes through is reduced. Therefore, in the present embodiment, an inductance element for reducing the peak value of the common mode noise such as the common mode choke coil including the windings 127a and 127b and the magnetic core 127c in FIG. 5 is not necessary. Therefore, according to the noise suppression circuit according to the present embodiment, the number of components is reduced as compared with a circuit configured by simply combining a cancellation mode noise suppression circuit for suppressing common mode noise and a normal mode noise filter circuit. Thus, the circuit can be reduced in size.
[0117]
In the present embodiment, the coupling coefficient of windings W21 and W22 only needs to be in the range of 0.001 to 0.999. The coupling coefficient is preferably set as appropriate according to the ratio of normal mode noise and common mode noise in an environment where the noise suppression circuit is used. In an environment where both normal mode noise and common mode noise exist to some extent, the coupling coefficient is preferably in the range of 0.2 to 0.8. In an environment where normal mode noise and common mode noise are present to the same extent, the coupling coefficient is preferably in the range of 0.4 to 0.6.
[0118]
In the present embodiment, the transmission path of the common mode injection signal includes capacitors 23 and 24 as elements for passing the injection signal. Therefore, according to the present embodiment, it is possible to detect a signal corresponding to the common mode noise and generate an injection signal having a phase opposite to that of the common mode noise using only the capacitors 23 and 24. Therefore, according to the present embodiment, the number of parts can be reduced.
[0119]
Next, an example of transmission characteristics of the noise suppression circuit according to the present embodiment will be described with reference to FIG. Here, the transmission characteristics of the noise suppression circuit according to the present embodiment shown in FIG. 11, the cancellation noise suppression circuit for common mode noise suppression shown in FIG. Asked. As the transmission characteristic, the frequency characteristic of gain was obtained.
[0120]
In this simulation, the following numerical values were used. First, the inductances of the windings W21 and W22 in FIG. 11 are both 60 μH, and their coupling coefficient is 0.8. In addition, the inductances of the windings W23, W24, and W25 in FIG. 11 are all 300 μH, and their coupling coefficient is 0.995. Further, the capacitances of the capacitors 23 and 24 in FIG. 11 are both 3300 pF. In addition, the inductances of the windings 125a, 125b, and 125c in FIG. 5 are all 300 μH, and their coupling coefficient is 0.995. Further, the inductances of the windings 127a and 127b in FIG. 5 are both 12 μH, and their coupling coefficient is 0.995. The inductance of the normal mode choke coil was 120 μH.
[0121]
The transmission characteristics obtained by the above simulation are shown in FIG. In FIG. 12, the line denoted by reference numeral 25 represents the transmission characteristic for the common mode signal of the noise suppression circuit according to the present embodiment and the transmission characteristic for the common mode signal of the cancellation type noise suppression circuit shown in FIG. Yes. The two transmission characteristics represented by the line indicated by reference numeral 25 are completely coincident. In FIG. 12, the line indicated by reference numeral 26 represents the transmission characteristics for the normal mode signal of the noise suppression circuit according to the present embodiment, and the line indicated by reference numeral 27 represents the normal mode signal of the normal mode choke coil. It represents the transmission characteristics. Comparing two transmission characteristics represented by lines 26 and 27, the transmission characteristic for the normal mode signal of the noise suppression circuit according to the present embodiment is more than the transmission characteristic for the normal mode signal of the normal mode choke coil. It turns out that it is excellent. This is because in the noise suppression circuit according to the present embodiment, the capacitors 23 and 24 contribute to the suppression of the normal mode signal. From FIG. 12, the noise suppression circuit according to the present embodiment exhibits the function of the canceling noise suppression circuit shown in FIG. 5 and the function of the normal mode choke coil, and is a normal that is superior to the normal mode choke coil. It can be seen that the mode noise suppression effect is exhibited.
[0122]
[Third Embodiment]
FIG. 13 is a circuit diagram showing a configuration of a noise suppression circuit according to the third embodiment of the present invention. The noise suppression circuit according to the present embodiment has the function of the cancellation noise suppression circuit for normal mode noise suppression shown in FIG. 3 and the function of the cancellation noise suppression circuit for common mode noise suppression shown in FIG. It has both.
[0123]
As in the first embodiment, the noise suppression circuit according to the present embodiment is a first pair that connects a pair of terminals 1a and 1b, another pair of terminals 2a and 2b, and the terminals 1a and 2a. A conductive line 3 and a second conductive line 4 connecting the terminals 1b and 2b are provided.
[0124]
The noise suppression circuit is further connected to the conductive wire 4 at the first winding W31 inserted into the conductive wire 3 at the predetermined first position P31a, the magnetic core 31, and the position P31b corresponding to the first position P31a. A second winding that is inserted and coupled to the first winding W31 via the magnetic core 31 so as to generate a leakage inductance, and suppresses common mode noise in cooperation with the first winding W31. W32 and a sixth winding W36 coupled to the first winding W31 and the second winding W32 via the magnetic core 31. The windings W31 and W32 and the magnetic core 31 constitute a common mode choke coil. That is, the windings W31 and W32 are oriented so that the magnetic fluxes induced in the magnetic core 31 are canceled by the currents flowing through the windings W31 and W32 when the normal mode current flows through the windings W31 and W32. It is wound around the magnetic core 31. Thus, the windings W31 and W32 suppress common mode noise and allow normal mode noise to pass. For example, the winding numbers of the windings W31, W32, and W36 are equal.
[0125]
The noise suppression circuit is further inserted into the conductive wire 3 at a second position P32a different from the first position P31a, and a third winding W33 for suppressing normal mode noise on the conductive wire 3, and the magnetic core 32. Are inserted into the conductive wire 4 at a position P32b corresponding to the second position P32a and coupled to the third winding W33 via the magnetic core 32 to suppress normal mode noise on the conductive wire 4. And a fifth winding W35 coupled to the third winding W33 and the fourth winding W34 via the magnetic core 32. The windings W33 and W34 are oriented so that the directions of magnetic fluxes induced in the magnetic core 32 by the currents flowing through the windings W33 and W34 when the current in the normal mode flows through the windings W33 and W34 are the same. It is wound around the magnetic core 32. As a result, the windings W33 and W34 suppress normal mode noise and allow common mode noise to pass. For example, the ratio of the number of turns of the windings W33, W34, and W35 is 1: 1: 2.
[0126]
The noise suppression circuit further has one end connected to the conductive wire 3 at a third position P33a different from the first position P31a and the second position P32a, and the other end connected to one end of the fifth winding W35. The capacitor 33 is provided. The other end of the fifth winding W35 is connected to the conductive wire 4 at a position P33b corresponding to the third position P33a. The capacitor 33 functions as a high-pass filter that passes a normal mode signal having a frequency equal to or higher than a predetermined value. A signal path from the position P33a through the capacitor 33 and the fifth winding W35 to the position P33b corresponds to the normal mode injection signal transmission path in the present invention. That is, this path transmits a normal mode injection signal injected into the conductive lines 3 and 4 in order to suppress normal mode noise.
[0127]
In the present embodiment, the coupling coefficient between the first winding W31 and the second winding W32 is smaller than 1. Therefore, the windings W31 and W32 generate a leakage inductance in each of the conductive wires 3 and 4. FIG. 13 includes virtual inductors L301 and L302 having inductances equal to these leakage inductances. The inductor L301 is inserted into the conductive wire 3 at a position between the first winding W31 and the third winding W33. The inductor L302 is inserted into the conductive wire 4 at a position between the second winding W32 and the fourth winding W34.
[0128]
In the present embodiment, the first position P31a is disposed between the second position P32a and the third position P33a. Thereby, the peak value of normal mode noise passing through the conductive lines 3 and 4 between the positions P32a and P32b and the positions P33a and P33b is caused by the leakage inductance (inductors L301 and L302) generated by the windings W31 and W32. Reduced.
[0129]
The windings W33, W34, W35, the magnetic core 32, the capacitor 33, and the inductors L301, L302 correspond to the normal mode noise suppression means in the present invention and exhibit the function of the cancellation type noise suppression circuit shown in FIG.
[0130]
The noise suppression circuit further includes a capacitor 34 having one end connected to the conductive wire 3 at a fourth position P34a different from the first position P31a and the other end connected to one end of the sixth winding W36. One end is connected to the conductive wire 4 at a position P34b corresponding to the fourth position P34a, and the other end is provided with the capacitor 35 connected to the other end of the capacitor 34 and one end of the sixth winding W36. The other end of the sixth winding W36 is grounded. The capacitors 34 and 35 function as a high-pass filter that allows a common mode signal having a frequency equal to or higher than a predetermined value to pass therethrough. A signal path from the positions P34a and P34b to the ground through the capacitors 34 and 35 and the sixth winding W36 corresponds to the common mode injection signal transmission path in the present invention. That is, this path transmits a common mode injection signal injected into the conductive lines 3 and 4 in order to suppress common mode noise.
[0131]
The noise suppression circuit further includes a seventh winding W37 inserted in the conductive wire 3 at the fifth position P35a between the first position P31a and the fourth position P34a, the magnetic core 36, A first wire that is inserted into the conductive wire 4 at a position P35b corresponding to the position P35a and coupled to the seventh winding W37 via the magnetic core 36, and suppresses common mode noise in cooperation with the seventh winding W37. 8 windings W38. The windings W37, W38 and the magnetic core 36 constitute a common mode choke coil. That is, the windings W37 and W38 are oriented so that the magnetic fluxes induced in the magnetic core 36 are offset by the currents flowing through the windings W37 and W38 when a normal mode current flows through the windings W37 and W38. It is wound around the magnetic core 36. Thus, the windings W37 and W38 suppress common mode noise and allow normal mode noise to pass. For example, the winding numbers of the windings W37 and W38 are equal.
[0132]
Windings W37 and W38 reduce the peak value of common mode noise passing through conductive lines 3 and 4 between positions P31a and 31b and positions P34a and P34b.
[0133]
The windings W31, W32, W36, the magnetic core 31, the capacitors 34, 35, the windings W37, W38, and the magnetic core 36 correspond to the common mode noise suppression means in the present invention, and cancel the noise suppression shown in FIG. Demonstrate the function of the circuit.
[0134]
In the present embodiment, the positions P35a and P35b are arranged between the positions P32a and P32b and the positions P33a and P33b. In this embodiment, in particular, positions P33a, P34a, P35a, P31a, and P32a are arranged in order from the side closer to the terminal 1a. Similarly, positions P33b, P34b, P35b, P31b, and P32b are arranged in order from the side closer to the terminal 1b. Has been placed. Note that the positional relationship between the positions P33a and P33b and the positions P34a and P34b may be opposite to the above case. Further, the position P33a and the position P34a may be the same position, and the position P33b and the position P34b may be the same position.
[0135]
In the present embodiment, the coupling coefficient between the seventh winding W37 and the eighth winding W38 is smaller than one. Therefore, the windings W37 and W37 generate a leakage inductance in each of the conductive wires 3 and 4. FIG. 13 includes virtual inductors L303 and L304 having inductances equal to these leakage inductances. The inductor L303 is inserted into the conductive wire 3 at a position between the third winding W33 and the seventh winding W37. The inductor L304 is inserted into the conductive wire 4 at a position between the fourth winding W34 and the eighth winding W38. Thereby, not only the leakage inductance (inductors L301 and L302) generated by the windings W31 and W32 but also the leakage inductance (inductors L303 and L304) generated by the windings W37 and W38, the positions P32a, P32b and the position P33a. , P33b, the peak value of normal mode noise passing through the conductive lines 3 and 4 is reduced.
[0136]
Next, the operation of the noise suppression circuit according to the present embodiment will be described. First, the normal mode of the noise suppression circuit when the source of normal mode noise is located closer to the positions P33a and P33b than the positions P32a and P32b, except for the position between the positions P32a and P32b and the positions P33a and P33b. The noise suppression action will be described. In this case, a signal corresponding to the normal mode noise is detected from the conductive lines 3 and 4 at the positions P33a and P33b by the capacitor 33. Further, based on this signal, a normal phase having a phase opposite to the normal mode noise is detected. A mode injection signal is generated. This normal mode injection signal is supplied to the fifth winding W35. The fifth winding W35 injects a normal mode injection signal into the conductive line 3 through the third winding W33 so as to have a phase opposite to the normal mode noise on the conductive line 3. Further, the fifth winding W35 injects a normal mode injection signal into the conductive line 4 through the fourth winding W34 so as to be in reverse phase to the normal mode noise on the conductive line 4. As a result, normal mode noise is suppressed in the conductive lines 3 and 4 from the positions P32a and P32b in the forward direction of the normal mode noise.
[0137]
Next, the normal mode noise is generated when the source of the normal mode noise is located closer to the positions P32a and P32b than the positions P33a and P33b except for the position between the positions P32a and P32b and the positions P33a and P33b. The mode noise suppressing action will be described. In this case, a signal corresponding to normal mode noise passing through the third winding W33 and the fourth winding W34 is induced in the fifth winding W35. In this manner, the fifth winding W35 detects a signal corresponding to the normal mode noise from the conductive lines 3 and 4 at the positions P32a and P32b, and generates a normal mode injection signal corresponding to this signal. . The normal mode injection signal passes through the capacitor 33 and is injected into the conductive lines 3 and 4 at the positions P33a and 33b. At the position P33a, a normal mode injection signal is injected into the conductive line 3 so as to be in opposite phase to the normal mode noise on the conductive line 3. At the position P33b, a normal mode injection signal is injected into the conductive line 4 so as to be in opposite phase to the normal mode noise on the conductive line 4. Thereby, the normal mode noise is suppressed in the conductive lines 3 and 4 from the positions P33a and P33b in the forward direction of the normal mode noise.
[0138]
Next, the common mode noise is generated when the common mode noise source is located closer to the positions P34a and P34b than the positions P31a and P31b except for the position between the positions P31a and P31b and the positions P34a and P34b. The mode noise suppressing action will be described. In this case, a signal corresponding to the common mode noise is detected by the capacitors 34 and 35 from the conductive lines 3 and 4 at the positions P34a and P34b. A common mode injection signal is generated. This common mode injection signal is supplied to the sixth winding W36. The sixth winding W36 conducts the common mode injection signal through the first winding W31 and the second winding W32 so as to be in opposite phase to the common mode noise on the conductive lines 3 and 4. Inject on lines 3 and 4. As a result, common mode noise is suppressed from the positions P31a and P31b in the direction of travel of the common mode noise in the conductive lines 3 and 4.
[0139]
Next, the common mode noise is generated when the source of the common mode noise is located closer to the positions P31a and P31b than the positions P34a and P34b except for the position between the positions P31a and P31b and the positions P34a and P34b. The mode noise suppressing action will be described. In this case, a signal corresponding to the common mode noise passing through the first winding W31 and the second winding W32 is induced in the sixth winding W36. In this manner, the sixth winding W36 detects a signal corresponding to the common mode noise from the conductive lines 3 and 4 at the positions P31a and P31b, and generates a common mode injection signal corresponding to this signal. . The common mode injection signal passes through the capacitors 34 and 35 and is injected into the conductive lines 3 and 4 at the positions P34a and P34b. The common mode injection signal is injected into the conductive lines 3 and 4 so as to have an opposite phase to the common mode noise on the conductive lines 3 and 4. As a result, the common mode noise is suppressed in the conductive lines 3 and 4 from the positions P34a and P34b in the traveling direction of the common mode noise.
[0140]
Thus, according to the noise suppression circuit according to the present embodiment, normal mode noise and common mode noise can be suppressed. In particular, the noise suppression circuit according to the present embodiment has both the function of a cancellation type noise suppression circuit for suppressing normal mode noise and the function of a cancellation type noise suppression circuit for suppressing common mode noise. Therefore, according to this noise suppression circuit, it is possible to effectively suppress normal mode noise and common mode noise in a wide frequency range by taking advantage of the cancellation type noise suppression circuit.
[0141]
By the way, it is conceivable to construct a circuit capable of suppressing normal mode noise and common mode noise by simply combining a cancellation noise suppression circuit for suppressing normal mode noise and a cancellation noise suppression circuit for suppressing common mode noise. . However, in this case, there is a problem that the number of parts included in the circuit increases and the circuit becomes large.
[0142]
In the present embodiment, in the conductive wires 3 and 4, the windings W31 and W32 coupled so as to generate a leakage inductance between the positions P32a and P32b and the positions P33a and P33b, and the leakage inductance are generated. Windings W37 and W38 coupled to each other are provided. The positions P32a and P32b and the positions P33a and P33b are caused by the leakage inductance generated by the windings W31 and W32 (inductors L301 and L302) and the leakage inductance generated by the windings W37 and W38 (inductors L303 and L304). The peak value of normal mode noise passing through the conductive lines 3 and 4 is reduced. Thereby, between the positions P32a and P32b and the positions P33a and P33b, the peak value of the normal mode noise passing through the conductive lines 3 and 4, and the conductive line 3 via the capacitor 33 and the fifth winding W35. The difference from the peak value of the injection signal injected into 4 is reduced.
[0143]
Thus, in the present embodiment, the leakage inductance generated by the common mode noise suppression windings W31 and W32 and the leakage inductance generated by the common mode noise suppression windings W37 and W38 are used. Thus, the peak value of normal mode noise passing through the conductive lines 3 and 4 between the positions P32a and P32b and the positions P33a and P33b is reduced. Therefore, in this embodiment, an inductance element for reducing the peak value of normal mode noise, such as the inductance element 117 in FIG. Therefore, according to the noise suppression circuit according to the present embodiment, compared to a circuit configured by simply combining a cancellation noise suppression circuit for suppressing normal mode noise and a cancellation noise suppression circuit for suppressing common mode noise. Thus, it is possible to reduce the number of parts and downsize the circuit.
[0144]
In the present embodiment, both the coupling coefficients of the windings W31 and W32 and the coupling coefficients of the windings W37 and W38 may be in the range of 0.001 to 0.999. The coupling coefficient is preferably set as appropriate according to the ratio of normal mode noise and common mode noise in an environment where the noise suppression circuit is used. In an environment where both normal mode noise and common mode noise exist to some extent, the coupling coefficient is preferably in the range of 0.2 to 0.8. In an environment where normal mode noise and common mode noise are present to the same extent, the coupling coefficient is preferably in the range of 0.4 to 0.6.
[0145]
In the present embodiment, the normal mode injection signal transmission path includes a capacitor 33 as an element for passing the injection signal. Therefore, according to the present embodiment, detection of a signal corresponding to normal mode noise and generation of an injection signal having a phase opposite to that of normal mode noise can be performed using only capacitor 33. Therefore, according to the present embodiment, the number of parts can be reduced.
[0146]
In the present embodiment, the transmission path of the common mode injection signal includes capacitors 34 and 35 as elements for passing the injection signal. Therefore, according to the present embodiment, it is possible to detect a signal corresponding to the common mode noise and generate an injection signal having a phase opposite to that of the common mode noise using only the capacitors 34 and 35. Therefore, according to the present embodiment, the number of parts can be reduced.
[0147]
Next, an example of transmission characteristics for the common mode signal of the noise suppression circuit according to the present embodiment will be described with reference to FIG. Here, the noise suppression circuit according to the present embodiment shown in FIG. 13, the canceling noise suppression circuit for common mode noise suppression (hereinafter referred to as a first comparative example) shown in FIG. 6 and a common mode noise filter circuit (hereinafter referred to as a second comparative example) and a common composed of windings W37 and W38 and a magnetic core 36 from the noise suppression circuit according to the present embodiment shown in FIG. For each of the circuits excluding the mode choke coil (hereinafter referred to as a third comparative example), transmission characteristics were obtained by simulation. As the transmission characteristic, the frequency characteristic of gain was obtained.
[0148]
In this simulation, the following numerical values were used. First, the inductances of the windings W31, W32, and W36 in FIG. 13 are all 300 μH, and their coupling coefficient is 0.995. In addition, the inductances of the windings W33 and W34 in FIG. 13 are 60 μH, the inductance of the winding W35 is 240 μH, and the coupling coefficient of the windings W33, W34, and W35 is 0.8. Further, the inductances of the windings W37 and W38 in FIG. 13 are both 300 μH, and their coupling coefficient is 0.995. Further, the capacitance of the capacitor 33 in FIG. 13 was 0.1 μH, and the capacitances of the capacitors 34 and 35 were 3300 pF. In addition, the inductances of the windings 125a, 125b, and 125c in FIG. 5 are all 300 μH, and their coupling coefficient is 0.995. Further, the inductances of the windings 127a and 127b in FIG. 5 are both 300 μH, and their coupling coefficient is 0.995. Further, the inductances of the windings 135a and 135b in FIG. 6 are both 300 μH, and their coupling coefficient is 0.995.
[0149]
The transmission characteristics obtained by the above simulation are shown in FIG. In FIG. 14, the line denoted by reference numeral 41 represents the transmission characteristic for the common mode signal of the noise suppression circuit according to the present embodiment and the transmission characteristic for the common mode signal of the first comparative example. The two transmission characteristics represented by the line denoted by reference numeral 41 are completely matched. In FIG. 14, the line denoted by reference numeral 42 represents the transmission characteristics for the common mode signal of the second comparative example, and the line denoted by reference numeral 43 represents the transmission characteristics for the common mode signal of the third comparative example. It represents. From FIG. 14, it can be seen that the noise suppression circuit according to the present embodiment has the same characteristics as the cancellation noise suppression circuit shown in FIG. Further, it can be seen from FIG. 14 that the noise suppression circuit according to the present embodiment exhibits a common mode noise suppression effect superior to that of the second comparative example. Furthermore, it can be seen from FIG. 14 that in the noise suppression circuit according to the present embodiment, the common mode choke coil composed of the windings W37 and W38 and the magnetic core 36 is effective in enhancing the common mode noise suppression effect.
[0150]
Next, an example of transmission characteristics for the normal mode signal of the noise suppression circuit according to the present embodiment will be described with reference to FIG. Here, the noise suppression circuit according to the present embodiment shown in FIG. 13, a normal mode choke coil (hereinafter referred to as a fourth comparative example), and the cancellation type for normal mode noise suppression shown in FIG. Transmission characteristics were determined by simulation for each of the noise suppression circuit (hereinafter referred to as the fifth comparative example) and the third comparative example. As the transmission characteristic, the frequency characteristic of gain was obtained.
[0151]
In this simulation, the following numerical values were used. First, the numerical values in the noise suppression circuit according to the present embodiment are the same as the numerical values when the transmission characteristics shown in FIG. 14 are obtained. The inductance of the fourth comparative example was 120 μH. Further, the inductances of the windings 115a and 115b in FIG. 3 are both 120 μH, and their coupling coefficient is 0.8. Further, the inductance of the inductance element 117 in FIG. 3 is 6 μH, and the capacitance of the capacitor 116 is 0.1 μF.
[0152]
The transmission characteristics obtained by the above simulation are shown in FIG. In FIG. 15, the line denoted by reference numeral 47 represents the transmission characteristic for the normal mode signal of the noise suppression circuit according to the present embodiment. In FIG. 15, lines indicated by reference numerals 44, 45, and 46 represent transmission characteristics for normal mode signals of the fourth comparative example, the fifth comparative example, and the third comparative example, respectively. From FIG. 15, it can be seen that the noise suppression circuit according to the present embodiment has better characteristics than the normal mode choke coil and the cancellation noise suppression circuit shown in FIG. I understand.
[0153]
[Fourth Embodiment]
FIG. 16 is a circuit diagram showing a configuration of a noise suppression circuit according to the fourth embodiment of the present invention. The noise suppression circuit according to the present embodiment has the function of the cancellation noise suppression circuit for normal mode noise suppression shown in FIG. 3 and the function of the cancellation noise suppression circuit for common mode noise suppression shown in FIG. It has both.
[0154]
As in the first embodiment, the noise suppression circuit according to the present embodiment is a first pair that connects a pair of terminals 1a and 1b, another pair of terminals 2a and 2b, and the terminals 1a and 2a. A conductive line 3 and a second conductive line 4 connecting the terminals 1b and 2b are provided.
[0155]
The noise suppression circuit is further inserted into the conductive wire 3 at a predetermined first position P41a, the first winding W41 for suppressing normal mode noise on the conductive wire 3, the magnetic core 51, and the first position. It is inserted into the conductive wire 4 at a position P41b corresponding to P41a, and is coupled to the first winding W41 via the magnetic core 51 so as to generate leakage inductance, thereby suppressing normal mode noise on the conductive wire 4. A second winding W42 and a sixth winding W46 coupled to the first winding W41 and the second winding W42 via the magnetic core 51 are provided. The windings W41 and W42 are oriented so that the direction of the magnetic flux induced in the magnetic core 51 by the current flowing through the windings W41 and W42 is the same when the normal mode current flows through the windings W41 and W42. It is wound around the magnetic core 51. As a result, the windings W41 and W42 suppress normal mode noise and allow common mode noise to pass. For example, the ratio of the number of turns of the windings W41, W42, and W46 is 1: 1: 2.
[0156]
The noise suppression circuit further includes a third winding W43 inserted into the conductive wire 3 at a second position P42a different from the first position P41a, a magnetic core 52, and a position corresponding to the second position P42a. A fourth winding W44 inserted into the conductive wire 4 at P42a and coupled to the third winding W43 via the magnetic core 52, and suppresses common mode noise in cooperation with the third winding W43; The third winding W43 and the fifth winding W45 coupled to the fourth winding W44 through the magnetic core 52 are provided. The windings W43 and W44 and the magnetic core 52 constitute a common mode choke coil. That is, the windings W43 and W44 are oriented so that the magnetic fluxes induced in the magnetic core 52 are offset by the currents flowing through the windings W43 and W44 when the normal mode current flows through the windings W43 and W44. It is wound around the magnetic core 52. Thus, the windings W43 and W44 suppress common mode noise and allow normal mode noise to pass. For example, the winding numbers of the windings W43, W44, and W45 are equal.
[0157]
The noise suppression circuit further has one end connected to the conductive wire 3 at a third position P43a different from the first position P41a and the second position P42a, and the other end connected to one end of the fifth winding W45. The capacitor 53 and one end connected to the conductive line 4 at a position P43b corresponding to the third position P43a, and the other end connected to the other end of the capacitor 53 and one end of the fifth winding W45. And. The other end of the fifth winding W45 is grounded. Capacitors 53 and 54 function as a high-pass filter that passes a common mode signal having a frequency equal to or higher than a predetermined value. A signal path from the positions P43a and P43b to the ground through the capacitors 53 and 54 and the fifth winding W45 corresponds to the common mode injection signal transmission path in the present invention. That is, this path transmits a common mode injection signal injected into the conductive lines 3 and 4 in order to suppress common mode noise.
[0158]
In the present embodiment, the coupling coefficient between the first winding W41 and the second winding W42 is smaller than one. Therefore, the windings W41 and W42 generate a leakage inductance in each of the conductive wires 3 and 4. FIG. 16 includes virtual inductors L401 and L402 having inductances equal to these leakage inductances. The inductor L401 is inserted into the conductive wire 3 at a position between the first winding W41 and the third winding W43. The inductor L402 is inserted into the conductive wire 4 at a position between the second winding W42 and the fourth winding W44.
[0159]
In the present embodiment, the first position P41a is disposed between the second position P42a and the third position P43a. Thereby, the peak value of the common mode noise passing through the conductive lines 3 and 4 between the positions P42a and P42b and the positions P43a and P43b is caused by the leakage inductance (inductors L401 and L402) generated by the windings W41 and W42. Reduced.
[0160]
The windings W43, W44, W45, the magnetic core 52, the capacitors 53, 54, and the inductors L401, L402 correspond to the common mode noise suppression means in the present invention and exhibit the function of the cancellation type noise suppression circuit shown in FIG. To do.
[0161]
The noise suppression circuit further includes a capacitor 55 having one end connected to the conductive wire 3 at a fourth position P44a different from the first position P41a and the other end connected to one end of the sixth winding W46. ing. The other end of the sixth winding W46 is connected to the conductive line 4 at a position P44b corresponding to the fourth position P44a. The capacitor 55 functions as a high-pass filter that passes a normal mode signal having a frequency equal to or higher than a predetermined value. A signal path from the position P44a through the capacitor 55 and the sixth winding W46 to the position P44b corresponds to the normal mode injection signal transmission path in the present invention. That is, this path transmits a normal mode injection signal injected into the conductive lines 3 and 4 in order to suppress normal mode noise.
[0162]
In the present embodiment, the coupling coefficient between the third winding W43 and the fourth winding W44 is smaller than one. Therefore, the windings W43 and W44 generate a leakage inductance in each of the conductive wires 3 and 4. FIG. 16 includes virtual inductors L403 and L404 having inductances equal to these leakage inductances.
[0163]
In the present embodiment, the second position P42a is disposed between the first position P41a and the fourth position P44a. The inductor L403 is inserted into the conductive wire 3 at a position between the third winding W43 and the position P44a. The inductor L404 is inserted into the conductive wire 4 at a position between the fourth winding W44 and the position P44b. Thereby, the peak value of the normal mode noise passing through the conductive wires 3 and 4 between the positions P41a and P41b and the positions P44a and P44b is reduced by the leakage inductance (inductors L403 and L404) generated by the windings W43 and W44. Is done.
[0164]
In the present embodiment, in particular, positions P43a, P41a, P42a, and P44a are arranged in order from the side closer to the terminal 1a, and similarly, positions P43b, P41b, P42b, and P44b are arranged in order from the side closer to the terminal 1b. .
[0165]
The windings W41, W42, W46, the magnetic core 51, the capacitor 55, and the inductors L403, L404 correspond to the normal mode noise suppression means in the present invention, and exhibit the function of the cancellation type noise suppression circuit shown in FIG.
[0166]
Next, the operation of the noise suppression circuit according to the present embodiment will be described. First, the common mode noise is generated in a common mode of the noise suppression circuit when the source of the common mode noise is located closer to the positions P43a and P43b than the positions P42a and P42b, except for the position between the positions P42a and P42b and the positions P43a and P43b. The noise suppression action will be described. In this case, a signal corresponding to the common mode noise is detected by the capacitors 53 and 54 from the conductive lines 3 and 4 at the positions P43a and P43b. A common mode injection signal is generated. This common mode injection signal is supplied to the fifth winding W45. The fifth winding W45 conducts the common mode injection signal via the third winding W43 and the fourth winding W44 so as to be in reverse phase to the common mode noise on the conductive lines 3 and 4. Inject on lines 3 and 4. As a result, common mode noise is suppressed from the positions P42a and P42b in the direction of travel of the common mode noise in the conductive lines 3 and 4.
[0167]
Next, the common mode noise is generated when the common mode noise source is located closer to the positions P42a and P42b than the positions P43a and P43b, except for the position between the positions P42a and P42b and the positions P43a and P43b. The mode noise suppressing action will be described. In this case, a signal corresponding to the common mode noise passing through the third winding W43 and the fourth winding W44 is induced in the fifth winding W45. In this manner, the fifth winding W45 detects a signal corresponding to the common mode noise from the conductive lines 3 and 4 at the positions P42a and P42b, and generates a common mode injection signal corresponding to this signal. . The common mode injection signal passes through the capacitors 53 and 54 and is injected into the conductive lines 3 and 4 at the positions P43a and P43b. The common mode injection signal is injected into the conductive lines 3 and 4 so as to have an opposite phase to the common mode noise on the conductive lines 3 and 4. As a result, common mode noise is suppressed from the positions P43a and P43b in the traveling direction of the common mode noise in the conductive lines 3 and 4.
[0168]
Next, the normal mode noise is generated when the source of the normal mode noise is located closer to the positions P44a and P44b than the positions P41a and P41b except for the position between the positions P41a and P41b and the positions P44a and P44b. The mode noise suppressing action will be described. In this case, a signal corresponding to the normal mode noise is detected from the conductive lines 3 and 4 at the positions P44a and P44b by the capacitor 55. Further, based on this signal, a normal phase that is in reverse phase to the normal mode noise is detected. A mode injection signal is generated. This normal mode injection signal is supplied to the sixth winding W46. The sixth winding W46 injects a normal mode injection signal into the conductive line 3 through the first winding W41 so as to be in opposite phase to the normal mode noise on the conductive line 3. In addition, the sixth winding W46 injects a normal mode injection signal into the conductive line 4 through the second winding W42 so as to be in opposite phase to the normal mode noise on the conductive line 4. As a result, the normal mode noise is suppressed in the conductive lines 3 and 4 from the positions P41a and P41b in the forward direction of the normal mode noise.
[0169]
Next, the normal mode noise is generated when the source of the normal mode noise is located closer to the positions P41a and P41b than the positions P44a and P44b except for the positions between the positions P41a and P41b and the positions P44a and P44b. The mode noise suppressing action will be described. In this case, a signal corresponding to normal mode noise passing through the first winding W41 and the second winding W42 is induced in the sixth winding W46. In this way, the sixth winding W46 detects the signal corresponding to the normal mode noise from the conductive lines 3 and 4 at the positions P41a and P41b, and the normal mode injection signal corresponding to this signal is generated. . The normal mode injection signal passes through capacitor 55 and is injected into conductive lines 3 and 4 at positions P44a and 44b. At the position P44a, a normal mode injection signal is injected into the conductive line 3 so as to be in opposite phase to the normal mode noise on the conductive line 3. At the position P44b, a normal mode injection signal is injected into the conductive line 4 so as to have an opposite phase to the normal mode noise on the conductive line 4. As a result, normal mode noise is suppressed from the positions P44a and P44b in the direction of travel of the normal mode noise in the conductive lines 3 and 4.
[0170]
Thus, according to the noise suppression circuit according to the present embodiment, normal mode noise and common mode noise can be suppressed. In particular, the noise suppression circuit according to the present embodiment has both the function of a cancellation type noise suppression circuit for suppressing normal mode noise and the function of a cancellation type noise suppression circuit for suppressing common mode noise. Therefore, according to this noise suppression circuit, it is possible to effectively suppress normal mode noise and common mode noise in a wide frequency range by taking advantage of the cancellation type noise suppression circuit.
[0171]
By the way, it is conceivable to construct a circuit capable of suppressing normal mode noise and common mode noise by simply combining a cancellation noise suppression circuit for suppressing normal mode noise and a cancellation noise suppression circuit for suppressing common mode noise. . However, in this case, there is a problem that the number of parts included in the circuit increases and the circuit becomes large.
[0172]
In the present embodiment, the conductive wires 3 and 4 are provided with windings W41 and W42 that are coupled so as to generate leakage inductance between the positions P42a and P42b and the positions P43a and P43b. The peak value of the common mode noise passing through the conductive wires 3 and 4 between the positions P42a and P42b and the positions P43a and P43b is reduced by the leakage inductance (inductors L401 and L402) generated by the windings W41 and W42. Is done. As a result, between the positions P42a and P42b and the positions P43a and P43b, the peak value of the common mode noise passing through the conductive lines 3 and 4, and the conductive lines via the capacitors 53 and 54 and the fifth winding W45. The difference with the peak value of the injection signal injected into 3 and 4 is reduced.
[0173]
As described above, in the present embodiment, the conductive lines 3 and 4 are provided between the positions P42a and P42b and the positions P43a and P43b by using the leakage inductance generated by the windings W41 and W42 for suppressing normal mode noise. The peak value of common mode noise that passes through is reduced. Therefore, in the present embodiment, an inductance element for reducing the peak value of the common mode noise such as the common mode choke coil including the windings 127a and 127b and the magnetic core 127c in FIG. 5 is not necessary.
[0174]
In the present embodiment, the conductive wires 3 and 4 are provided with windings W43 and W44 that are coupled so as to generate leakage inductance between the positions P41a and P41b and the positions P44a and P44b. The peak value of normal mode noise passing through the conductive lines 3 and 4 between the positions P41a and P41b and the positions P44a and P44b is reduced by the leakage inductance (inductors L403 and L404) generated by the windings W43 and W44. Is done. As a result, between the positions P41a and P41b and the positions P44a and P44b, the peak value of the normal mode noise passing through the conductive lines 3 and 4, the conductive line 3 via the capacitor 55 and the sixth winding W46. The difference from the peak value of the injection signal injected into 4 is reduced.
[0175]
As described above, in the present embodiment, the conductive wires 3 and 4 are provided between the positions P41a and P41b and the positions P44a and P44b using the leakage inductance generated by the windings W43 and W44 for suppressing the common mode noise. The peak value of normal mode noise that passes through is reduced. Therefore, in this embodiment, an inductance element for reducing the peak value of normal mode noise, such as the inductance element 117 in FIG.
[0176]
For these reasons, the noise suppression circuit according to the present embodiment is configured by simply combining the cancellation noise suppression circuit for suppressing normal mode noise and the cancellation noise suppression circuit for suppressing common mode noise. Compared to a circuit, the number of parts can be reduced and the circuit can be downsized.
[0177]
In the present embodiment, both the coupling coefficients of the windings W41 and W42 and the coupling coefficients of the windings W43 and W44 may be in the range of 0.001 to 0.999. The coupling coefficient is preferably set as appropriate according to the ratio of normal mode noise and common mode noise in an environment where the noise suppression circuit is used. In an environment where both normal mode noise and common mode noise exist to some extent, the coupling coefficient is preferably in the range of 0.2 to 0.8. In an environment where normal mode noise and common mode noise are present to the same extent, the coupling coefficient is preferably in the range of 0.4 to 0.6.
[0178]
In the present embodiment, the transmission path of the normal mode injection signal includes a capacitor 55 as an element for passing the injection signal. Therefore, according to the present embodiment, detection of a signal corresponding to normal mode noise and generation of an injection signal having a phase opposite to that of normal mode noise can be performed using only capacitor 55. Therefore, according to the present embodiment, the number of parts can be reduced.
[0179]
In the present embodiment, the transmission path of the common mode injection signal includes capacitors 53 and 54 as elements for passing the injection signal. Therefore, according to the present embodiment, it is possible to detect a signal corresponding to the common mode noise and generate an injection signal having a phase opposite to that of the common mode noise using only the capacitors 53 and 54. Therefore, according to the present embodiment, the number of parts can be reduced.
[0180]
Next, an example of transmission characteristics of the noise suppression circuit according to the present embodiment will be described with reference to FIG. Here, the noise suppression circuit according to the present embodiment shown in FIG. 16, the cancellation type noise suppression circuit for normal mode noise suppression shown in FIG. 3, and the cancellation type for common mode noise suppression shown in FIG. For each of the noise suppression circuits, transmission characteristics were obtained by simulation. As the transmission characteristic, the frequency characteristic of gain was obtained.
[0181]
In this simulation, the following numerical values were used. First, the inductances of the windings W41 and W42 in FIG. 16 are 60 μH, the inductance of the winding W46 is 240 μH, and the coupling coefficient of the windings W41, W42, and W46 is 0.8. Further, the inductances of the windings W43, W44, and W45 in FIG. 16 are all 300 μH, and their coupling coefficient is 0.995. Further, the capacitances of the capacitors 53 and 54 in FIG. 16 are both 3300 pF, and the capacitance of the capacitor 55 is 0.1 μF. Further, the inductances of the windings 115a and 115b in FIG. 3 are both 120 μH, and their coupling coefficient is 0.8. Further, the inductance of the inductance element 117 in FIG. 3 is 3 μH, and the capacitance of the capacitor 116 is 0.1 μF. In addition, the inductances of the windings 125a, 125b, and 125c in FIG. 5 are all 300 μH, and their coupling coefficient is 0.995. Further, the inductances of the windings 127a and 127b in FIG. 5 are both 12 μH, and their coupling coefficient is 0.995.
[0182]
The transmission characteristics obtained by the above simulation are shown in FIG. In FIG. 17, the line denoted by reference numeral 61 represents the transmission characteristic for the common mode signal of the noise suppression circuit according to the present embodiment, and the transmission characteristic for the common mode signal of the cancellation type noise suppression circuit shown in FIG. Yes. The two transmission characteristics represented by the line denoted by reference numeral 61 are completely matched. In FIG. 17, the line denoted by reference numeral 62 represents the transmission characteristic for the normal mode signal of the noise suppression circuit according to the present embodiment, and the line denoted by reference numeral 63 represents the cancellation noise suppression shown in FIG. The transmission characteristic with respect to the normal mode signal of a circuit is represented. Two transmission characteristics represented by lines 62 and 63 are approximated. From FIG. 17, the noise suppression circuit according to the present embodiment has the function of the cancellation type noise suppression circuit for suppressing normal mode noise shown in FIG. 3 and the cancellation type noise suppression for suppressing common mode noise shown in FIG. It can be seen that the circuit functions.
[0183]
The noise suppression circuit according to each of the embodiments described above is a means for reducing ripple voltage and noise generated by the power conversion circuit, noise on the power line in power line communication, and communication signals on the indoor power line are outdoors. It can be used as means for preventing leakage to the power line.
[0184]
In addition, this invention is not limited to said each embodiment, A various change is possible. In the present invention, when the normal mode noise suppression means has a configuration of a cancellation type noise suppression circuit, the common mode noise suppression means has two windings that generate leakage inductance, and these two windings cancel each other. What is necessary is just to arrange | position between the detection position of the noise in the type | mold noise suppression circuit, and the injection | pouring position of an injection signal. In addition, when the common mode noise suppression unit has a configuration of a cancellation type noise suppression circuit, the normal mode noise suppression unit has two windings that generate leakage inductance, and these two windings are the cancellation type noise suppression unit. What is necessary is just to arrange | position between the detection position of the noise in the suppression circuit, and the injection position of the injection signal. Therefore, the noise suppression circuit of the present invention may have a configuration other than those in the first to fourth embodiments as long as it satisfies at least one of the above two conditions.
[0185]
In each embodiment, a high-pass filter having a different configuration or a band-pass filter may be provided instead of the high-pass filter including only a capacitor.
[0186]
【The invention's effect】
As described above, according to the noise suppression circuit of the present invention, normal mode noise and common mode noise can be suppressed, and the noise suppression circuit can be reduced in size.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of a noise suppression circuit according to a first embodiment of the present invention.
FIG. 2 is a circuit diagram showing a basic configuration of a cancellation type noise suppression circuit.
FIG. 3 is a circuit diagram showing an example of a configuration of a cancellation type noise suppression circuit for suppressing normal mode noise.
4 is a circuit diagram for explaining the operation of the cancellation type noise suppression circuit shown in FIG. 3;
FIG. 5 is a circuit diagram showing an example of a configuration of a cancellation type noise suppression circuit for suppressing common mode noise.
FIG. 6 is a circuit diagram showing a common mode noise filter circuit.
7 is a circuit diagram showing an equivalent circuit of the filter circuit shown in FIG. 6. FIG.
FIG. 8 is a circuit diagram showing a normal mode noise filter circuit.
9 is a circuit diagram showing an equivalent circuit of the filter circuit shown in FIG. 8. FIG.
FIG. 10 is a characteristic diagram showing an example of transmission characteristics of the noise suppression circuit according to the first embodiment of the present invention.
FIG. 11 is a circuit diagram showing a configuration of a noise suppression circuit according to a second embodiment of the present invention.
FIG. 12 is a characteristic diagram showing an example of transmission characteristics of the noise suppression circuit according to the second embodiment of the present invention.
FIG. 13 is a circuit diagram showing a configuration of a noise suppression circuit according to a third embodiment of the present invention.
FIG. 14 is a characteristic diagram showing an example of transmission characteristics for a common mode signal of a noise suppression circuit according to a third embodiment of the present invention.
FIG. 15 is a characteristic diagram illustrating an example of transmission characteristics for a normal mode signal of a noise suppression circuit according to a third embodiment of the present invention;
FIG. 16 is a circuit diagram showing a configuration of a noise suppression circuit according to a fourth embodiment of the present invention.
FIG. 17 is a characteristic diagram illustrating an example of transmission characteristics of a noise suppression circuit according to a fourth embodiment of the present invention.
[Explanation of symbols]
3, 4 ... conductive wire, 11, 12 ... magnetic core, 13 ... capacitor, W11 ... first winding, W12 ... second winding, W13 ... third winding, W14 ... fourth winding, W15: fifth winding, L101, L102: inductor.

Claims (9)

Normal mode noise suppression means that suppresses normal mode noise that is transmitted by the first and second conductive lines and causes a potential difference between these conductive lines and the first and second conductive lines propagate in the same phase. A common mode noise suppression means for suppressing common mode noise,
The common mode noise suppression means is inserted into the second conductive line at a position corresponding to the first winding and the first winding inserted into the first conductive line at a predetermined first position. And a second winding coupled to the first winding to generate leakage inductance, and cooperating with the first winding to suppress common mode noise,
The normal mode noise suppression means is inserted into the first conductive line at a second position different from the first position, and a third winding for suppressing normal mode noise on the first conductive line; A fourth winding inserted into the second conductive line at a position corresponding to the second position and suppressing normal mode noise on the second conductive line, and coupled to the third and fourth windings A fifth winding, connected to the fifth winding, connected to the first conductive line at a third position different from the first and second positions, and further corresponding to the third position And a normal mode injection signal transmission line for transmitting a normal mode injection signal injected into the first and second conductive lines to be connected to the second conductive line at a position to suppress normal mode noise. ,
The first position is disposed between the second position and the third position, whereby the second position and the third position are caused by leakage inductance generated by the first and second windings. The peak value of normal mode noise passing through the first and second conductive lines between the positions is reduced,
When the source of the normal mode noise is at a position closer to the third position than the second position except for the position between the second position and the third position, the normal mode injection signal The transmission path generates the normal mode injection signal based on signals detected from the first and second conductive lines at the third position and a position corresponding to the third position, and the normal mode injection signal is the first mode injection signal. 5 is supplied to the fifth winding, and the fifth winding transmits the normal mode injection signal through the third winding so as to be in reverse phase with respect to the normal mode noise on the first conductive line. And injecting the normal mode injection signal into the second conductive line through the fourth winding so as to be in opposite phase to the normal mode noise on the second conductive line. ,
If the source of the normal mode noise is at a position closer to the second position than the third position, except for the position between the second position and the third position, the fifth winding The normal mode injection signal is generated by a line based on signals detected from the first and second conductive lines at the second position and a position corresponding to the second position, and the normal mode injection signal transmission path is: In the third position, the normal mode injection signal is injected into the first conductive line so as to be in opposite phase to the normal mode noise on the first conductive line, and at a position corresponding to the third position. A noise suppression circuit, wherein the normal mode injection signal is injected into the second conductive line so as to be in opposite phase to the normal mode noise on the second conductive line. The noise suppression circuit according to claim 1, wherein the normal mode injection signal transmission path includes a capacitor for allowing the normal mode injection signal to pass therethrough. The common mode noise suppression means further includes a sixth winding coupled to the first and second windings and a fourth winding connected to the sixth winding and different from the first position. Connected to the first conductive line at a position of the second conductive line and further connected to the second conductive line at a position corresponding to the fourth position, and connected to the first and second conductive lines to suppress common mode noise. A common mode injection signal transmission path for transmitting the injected common mode injection signal, and a seventh winding inserted into the first conductive line at a fifth position between the first position and the fourth position; And inserted into the second conductive line at a position corresponding to the fifth position and coupled to the seventh winding, and cooperates with the seventh winding to suppress common mode noise. 8 windings, and the seventh and eighth windings are the first windings. Reducing the peak value of common mode noise passing through the first and second conductive lines between the position and the fourth position,
When the source of the common mode noise is at a position closer to the fourth position than the first position except for a position between the first position and the fourth position, the common mode injection signal The transmission path generates the common mode injection signal based on signals detected from the first and second conductive lines at the fourth position and the corresponding position, and the common mode injection signal is 6 so that the sixth winding is in reverse phase with respect to the common mode noise on the first and second conductive lines via the first and second windings. Injecting the common mode injection signal into the first and second conductive lines;
If the source of the common mode noise is at a position closer to the first position than the fourth position except for the position between the first position and the fourth position, the sixth winding The common mode injection signal is generated by a line based on signals detected from the first and second conductive lines at the first position and a position corresponding thereto, and the common mode injection signal transmission line is Injecting the common mode injection signal into the first and second conductive lines at the fourth position and the corresponding position so as to be in opposite phase to the common mode noise on the first and second conductive lines. The noise suppression circuit according to claim 1 or 2, wherein: The seventh winding and the eighth winding are coupled to generate a leakage inductance,
The fifth position is disposed between the second position and the third position, so that in addition to the leakage inductance generated by the first and second windings, the seventh and eighth positions The peak value of normal mode noise passing through the first and second conductive lines between the second position and the third position is also reduced by the leakage inductance generated by the winding. The noise suppression circuit according to claim 3. 5. The noise suppression circuit according to claim 3, wherein the common mode injection signal transmission path includes a capacitor for allowing the common mode injection signal to pass therethrough. Normal mode noise suppression means that suppresses normal mode noise that is transmitted by the first and second conductive lines and causes a potential difference between these conductive lines and the first and second conductive lines propagate in the same phase. A common mode noise suppression means for suppressing common mode noise,
The normal mode noise suppression means is inserted into the first conductive line at a predetermined first position, and corresponds to the first winding for suppressing normal mode noise on the first conductive line, and the first position. And a second winding that is inserted into the second conductive line at a position where it is coupled to the first winding so as to generate a leakage inductance and suppresses normal mode noise on the second conductive line. Have
The common mode noise suppression means includes a third winding inserted into the first conductive line at a second position different from the first position, and a second winding at a position corresponding to the second position. A fourth winding inserted into a conductive wire and coupled to the third winding to suppress the common mode noise in cooperation with the third winding; and the third and fourth turns A fifth winding coupled to a line; connected to the fifth winding; connected to a first conductive line at a third position different from the first and second positions; and The common mode injection signal transmission is connected to the second conductive line at a position corresponding to position 3, and transmits a common mode injection signal injected into the first and second conductive lines to suppress common mode noise. Road and
The first position is disposed between the second position and the third position, whereby the second position and the third position are caused by leakage inductance generated by the first and second windings. The peak value of the common mode noise passing through the first and second conductive lines between the positions is reduced,
When the source of the common mode noise is at a position closer to the third position than the second position except for a position between the second position and the third position, the common mode injection signal The transmission path generates the common mode injection signal based on signals detected from the first and second conductive lines at the third position and a position corresponding thereto, and the common mode injection signal is 5, and the fifth winding is in reverse phase with respect to the common mode noise on the first and second conductive lines via the third and fourth windings. Injecting the common mode injection signal into the first and second conductive lines;
If the source of the common mode noise is at a position closer to the second position than the third position, except for the position between the second position and the third position, the fifth winding The common mode injection signal is generated by a line based on signals detected from the first and second conductive lines at the second position and a position corresponding thereto, and the common mode injection signal transmission line includes: Injecting the common mode injection signal into the first and second conductive lines at the third position and the corresponding position so as to be in opposite phase to the common mode noise on the first and second conductive lines. A noise suppression circuit characterized by: The noise suppression circuit according to claim 6, wherein the common mode injection signal transmission path includes a capacitor for allowing the common mode injection signal to pass therethrough. The normal mode noise suppression means further includes a sixth winding coupled to the first and second windings and a fourth winding connected to the sixth winding and different from the first position. Is connected to the first conductive line at a position of the first conductive line, and is further connected to the second conductive line at a position corresponding to the fourth position, and is connected to the first and second conductive lines to suppress normal mode noise. A normal mode injection signal transmission path for transmitting a normal mode injection signal to be injected;
The second position is disposed between the first position and the fourth position, whereby the first position and the fourth position are caused by a leakage inductance generated by the third and fourth windings. The peak value of normal mode noise passing through the first and second conductive lines between the positions of
When the source of the normal mode noise is at a position closer to the fourth position than the first position except for a position between the first position and the fourth position, the normal mode injection signal The transmission path generates the normal mode injection signal based on signals detected from the first and second conductive lines at the fourth position and a position corresponding thereto, and the normal mode injection signal is the first mode injection signal. 6, and the sixth winding transmits the normal mode injection signal through the first winding so that the normal mode injection signal is in reverse phase with respect to the normal mode noise on the first conductive line. And injecting the normal mode injection signal into the second conductive line through the second winding so as to be in opposite phase to the normal mode noise on the second conductive line. ,
If the source of the normal mode noise is at a position closer to the first position than the fourth position, except for the position between the first position and the fourth position, the sixth winding The normal mode injection signal is generated by a line based on signals detected from the first and second conductive lines at the first position and a position corresponding to the first position, and the normal mode injection signal transmission path is: In the fourth position, the normal mode injection signal is injected into the first conductive line so as to be in opposite phase to the normal mode noise on the first conductive line, and at a position corresponding to the fourth position. 8. The noise suppression circuit according to claim 6, wherein the normal mode injection signal is injected into the second conductive line so as to be in opposite phase to the normal mode noise on the second conductive line. 9. The noise suppression circuit according to claim 8, wherein the normal mode injection signal transmission path includes a capacitor for allowing the normal mode injection signal to pass therethrough.

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