JP2002204189A - Power line noise filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce a noise on a power line in a wide frequency band and to effectively decrease not only a continuous noise but also a sudden noise. SOLUTION: A power line noise filter 10 detects a change of a current at conductive lines 1a, 1b of the power line 1 by a detector 11 and hence detects the noise of a common mode of current properties on the line 1. A reverse phase signal generator 12 generates a reverse phase signal as a signal having a reverse phase to the noise detected by the detector 11. Further, the change of the same current corresponding to the reverse phase signal is given to the two lines 1a, 1b of the line 1 for the two lines 1a, 1b of the line 1 by an injection circuit 13. Thus, the noise of the common mode of the current properties on the line 1 is cancelled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power line noise filter for reducing noise on a power line.

[0002]

2. Description of the Related Art As one of communication technologies in homes, offices, and the like, power line communication in which a high-frequency signal is superimposed on a power line for communication is known. In this power line communication, sudden noise (hereinafter, also referred to as noise) occurs in an unspecified frequency band on the power line due to the operation of various electric / electronic devices connected to the power line.
There has been a problem that the communication quality is lowered such as an increase in an error rate.

[0003] Even when power line communication is not performed, noise generated on a power line due to operation of a device connected to the power line may adversely affect other devices connected to the same power line.

[0004] The noise generated on the power line includes 2
There are common mode noise that propagates in the same phase through two conductive lines, and normal mode noise that occurs between the two conductive lines. Noise generated on the power line includes current noise in which current fluctuates and voltage noise in which voltage fluctuates.

As a countermeasure against the above-mentioned problem caused by noise, it is conceivable to use a noise filter for electromagnetic interference (EMI) (hereinafter, referred to as an EMI filter). An EMI filter generally includes a common mode choke coil, a normal mode choke coil,
It has a configuration of an LC filter (a filter composed of an inductor and a capacitor) formed by combining discrete elements such as a capacitor and a Y capacitor.

Japanese Patent Application Laid-Open No. Hei 7-115339 discloses a line filter that absorbs noise current. In this line filter, a noise current flows through a first transformer including a primary coil and a secondary coil, a second transformer including a primary coil and a secondary coil, and a primary coil of the first transformer. Amplifying means for amplifying the noise current electromagnetically induced in the secondary coil of the first transformer, and flowing the noise current amplified by the amplifying means to the secondary coil of the second transformer, This changes the impedance of the primary coil of the transformer. In this line filter, the noise attenuation effect is enhanced by adjusting the impedance of the primary coil of the second transformer.

[0007] Japanese Patent Application Laid-Open No. 10-303,674 discloses an AC line filter for reducing noise on an AC power supply line. This AC line filter is
A common mode choke coil to which a third winding is added, a noise extraction circuit for extracting common mode noise on the AC power supply line, a noise amplification circuit for amplifying the extracted common mode noise, and an output of the noise amplification circuit And a current supply circuit for supplying a current for applying a reverse-phase electromotive force to the third winding of the common mode choke coil according to In this AC line filter, common mode noise on the AC power supply line is extracted by a noise extraction circuit, and the extracted common mode noise is amplified by a noise amplifier circuit. The third winding of the common mode choke coil is supplied with a current for giving an electromotive force having a negative phase. Thereby, common mode noise on the AC power supply line is reduced.

[0008]

The conventional EMI filter having the structure of the LC filter has the advantage that the circuit structure is simple, but also has the following disadvantages (1) to (3).

(1) Since a conventional EMI filter has a unique resonance frequency determined by inductance and capacitance, a desired attenuation can be obtained only in a narrow frequency band.

(2) Since the frequency band, magnitude, and nature of the generated noise vary depending on the type of electric / electronic device, it is necessary to optimize the EMI filter according to the device that generates the noise. For this reason, every time a device is designed,
In order to comply with the noise standard, trial and error for optimizing the EMI filter is repeated, so that it takes time to measure and evaluate the EMI filter, and it is difficult to standardize the EMI filter.

(3) In the conventional EMI filter, since the frequency band in which a desired attenuation is obtained is narrow, the noise frequency varies due to the variation of the noise source and the variation of the attenuation characteristic due to the variation of the EMI filter. There is a problem that the effect of reduction varies.

On the other hand, in the line filter disclosed in Japanese Patent Application Laid-Open No. 7-115339, a current having the same phase with a one-cycle delay from the noise current detected by the first transformer is used.
By flowing the current through the secondary coil of the second transformer, the impedance of the primary coil of the second transformer is adjusted. Therefore, this line filter may be effective for reducing continuous noise whose frequency does not change,
Sudden noise cannot be offset. FIG. 4 of JP-A-7-115339 shows a configuration example of a line filter, in which a line wire is wound so as to straddle two cores, and a secondary coil of a first transformer and a second coil are respectively wound around each core. 2 shows a configuration in which a secondary coil of a transformer is wound. However, such a configuration has a problem that the two cores are likely to be displaced and wiring is difficult.

In the AC line filter disclosed in Japanese Patent Application Laid-Open No. Hei 10-303674, as can be seen from FIGS. 1 and 2 of the aforementioned publication, an HPF (high-pass filter) is used.
Is used to detect common mode noise by detecting voltage fluctuations on the neutral line,
This common mode noise is amplified by a noise amplifier circuit, and a current for generating a reverse-phase electromotive force to the third winding of the common mode choke coil is generated by a current supply circuit according to the output of the noise amplifier circuit. This current is supplied to the third winding of the common mode choke coil.

As described above, the AC line filter detects the voltage of the common mode noise (hereinafter, referred to as a noise voltage), amplifies the noise voltage, and outputs a current having a phase opposite to that of the common mode noise (hereinafter, referred to as a noise voltage). , And a negative-phase current), and the common-mode noise is canceled by the negative-phase current.

However, in the AC line filter, in the process of amplifying the noise voltage and converting the noise voltage to the negative-phase current, a delay of the negative-phase current with respect to the noise voltage occurs. Further, the waveform of the noise voltage does not completely correspond to the waveform of the reverse-phase current. For these reasons, it is difficult for the AC line filter to accurately cancel the common mode noise on the AC power supply line.

The AC line filter basically reduces common mode noise by using a common mode choke coil, and supplies a common-mode current to the third winding of the common mode choke coil. The effect of mode noise reduction is enhanced. Therefore, this AC line filter has a problem that it is difficult to reduce noise in a wide frequency band because the attenuation characteristic depends on the characteristic of the common mode choke coil.

In the AC line filter, the HPF for extracting the common mode noise is provided between the neutral line and the frame ground, and the third winding for canceling the common mode noise is provided. Is connected between the frame ground and the current supply circuit. Therefore, this AC line filter does not function when there is no frame ground, and can cancel only the common mode noise between the frame ground and the neutral line. That is, the applicable range of the AC line filter is extremely limited.

FIG. 5 of JP-A-53-54447 discloses a filter for blocking a carrier wave on a power line. The filter includes a pair of input terminals, a pair of output terminals, a parallel resonance circuit provided between one input terminal and one output terminal, and a series resonance circuit provided between the pair of output terminals. And In the parallel resonance circuit of this filter, on the magnetic core, the magnetic flux of the commercial current on which the high-frequency signal is superimposed and the magnetic flux of the commercial current from which the high-frequency signal has been removed by the low-pass filter cancel out, and To increase the impedance. The principle of carrier rejection in this filter is completely different from the principle of noise reduction in the power line noise filter of the present invention described later.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to effectively reduce noise on a power line in a wide frequency band, and to provide not only continuous noise but also sudden noise. An object of the present invention is to provide a power line noise filter capable of effectively reducing noise.

[0020]

A first power line noise filter according to the present invention detects noise on a power line by detecting a change in current in the power line, and a noise detected by the noise detection unit. A negative-phase signal generating means for generating a negative-phase signal which is a signal having a negative phase with the noise; Noise canceling means for canceling the noise.

In the first power line noise filter of the present invention,
The noise on the power line is detected by detecting the fluctuation of the current in the power line by the noise detecting means, and a reverse-phase signal which is a signal having a phase opposite to the detected noise is generated by the negative-phase signal generating means, and the noise is canceled. By the means, a change in current corresponding to the negative-phase signal is given to the power line, thereby canceling noise on the power line.

In the first power line noise filter of the present invention, the noise detecting means detects noise propagating in the same phase on the two conductive lines on the power line, and the noise canceling means detects the noise on the two conductive lines on the power line. Alternatively, the same change in current may be applied.

In the first power line noise filter of the present invention, the noise detecting means detects noise generated in each of the two conductive lines in the power line for each conductive line, and the anti-phase signal generating means includes: A negative phase signal is generated for each conductive line corresponding to the noise of each conductive line detected by the noise detecting means, and the noise canceling means generates a negative phase signal for each of the two conductive lines on the power line. A change in current corresponding to the negative-phase signal for each conductive line generated by the means may be provided.

A second power line noise filter according to the present invention includes a noise detecting means for detecting noise on the power line by detecting a voltage change in the power line, and a signal having a phase opposite to that of the noise detected by the noise detecting means. A negative-phase signal generating means for generating a negative-phase signal, and a noise for canceling noise on the power line by giving a voltage change corresponding to the negative-phase signal generated by the negative-phase signal generating means to the power line. With offsetting means.

In the second power line noise filter of the present invention,
Noise on the power line is detected by detecting fluctuations in the voltage on the power line by the noise detection means, and a negative-phase signal, which is a signal having a phase opposite to the detected noise, is generated by the negative-phase signal generation means, and the noise is canceled. By the means, a change in voltage corresponding to the negative-phase signal is applied to the power line, thereby canceling noise on the power line.

In the second power line noise filter of the present invention, the noise detecting means detects noise propagating in the same phase on the two conductive lines on the power line, and the noise canceling means detects noise on the two conductive lines on the power line. Alternatively, the same voltage change may be applied.

In the second power line noise filter of the present invention, the noise detecting means detects noise generated in each of the two conductive lines in the power line for each conductive line, and the anti-phase signal generating means includes: A negative phase signal is generated for each conductive line corresponding to the noise of each conductive line detected by the noise detecting means, and the noise canceling means generates a negative phase signal for each of the two conductive lines on the power line. A change in voltage corresponding to the negative-phase signal for each conductive line generated by the means may be given.

A third power line noise filter according to the present invention comprises a first noise detecting means for detecting a first noise on a power line by detecting a fluctuation of a current in the power line, and a first noise detecting means. First negative-phase signal generating means for generating a first negative-phase signal which is a signal having a negative phase with respect to the detected first noise, and a first negative-phase signal generating means for the power line generated by the first negative-phase signal generating means. A first noise canceling means for canceling the first noise on the power line by giving a change in current corresponding to the one negative-phase signal, and a second noise on the power line by detecting a voltage change in the power line. Second noise detection means for detecting the noise of the second noise, and second negative-phase signal generation for generating a second negative-phase signal which is a signal having the reverse phase to the second noise detected by the second noise detection means Means and a second
And a second noise canceling means for canceling the second noise on the power line by giving a voltage change corresponding to the second negative phase signal generated by the negative phase signal generating means. .

In the third power line noise filter of the present invention,
The first noise detecting means detects a first noise on the power line by detecting a fluctuation of a current in the power line, and a first signal having a signal opposite in phase to the detected first noise.
Is generated by the first anti-phase signal generating means, and the first noise canceling means gives a change in current corresponding to the first anti-phase signal to the power line, and the One noise cancels out. Further, the second noise on the power line is detected by detecting a voltage change in the power line by the second noise detecting means, and a second inverse noise signal having a phase opposite to that of the detected second noise is detected. A phase signal is generated by the second negative-phase signal generating means, and a voltage change corresponding to the second negative-phase signal is applied to the power line by the second noise canceling means, so that the second Noise cancels out.

In the third power line noise filter of the present invention, the first noise detecting means detects the first noise propagating in the same phase on the two conductive lines in the power line, and the first noise canceling means includes: Giving the same change in current to the two conductive lines in the power line, the second noise detecting means detects a second noise propagating in the same phase through the two conductive lines in the power line, The noise canceling means may apply the same voltage change to two conductive lines in the power line.

Further, in the third power line noise filter of the present invention, the first noise detecting means detects the first noise generated in each of the two conductive lines in the power line for each conductive line. The first negative-phase signal generating means generates a first negative-phase signal for each conductive line corresponding to the first noise for each conductive line detected by the first noise detecting means, and generates the first noise. The canceling means applies, to each of the two conductive lines in the power line, a change in current corresponding to the first negative-phase signal for each conductive line generated by the first negative-phase signal generating means, The second noise detecting means detects the second noise generated in each of the two conductive lines in the power line for each conductive line, and the second antiphase signal generating means detects the second noise in the power line by the second noise detecting means. Generating a second negative-phase signal for each conductive line corresponding to the second noise for each conductive line Noise canceling means gives a voltage change corresponding to the second negative-phase signal for each conductive line generated by the second negative-phase signal generating means to each of the two conductive lines in the power line. You may.

The fourth power line noise filter of the present invention is disposed at a predetermined position on the power line, and detects noise on the power line by detecting a current fluctuation or a voltage fluctuation on the power line, An anti-phase signal generating means for generating an anti-phase signal which is an anti-phase signal to the noise detected by the noise detecting means, and being arranged at a position different from the detecting means on the power line, and detecting a fluctuation of current in the noise detecting means Therefore, when noise is detected, a change in current corresponding to the negative-phase signal generated by the negative-phase signal generating means is given to the power line, and the noise is detected by detecting a fluctuation in voltage by the noise detecting means. If detected, a change in voltage corresponding to the negative-phase signal generated by the negative-phase signal generating means is applied to the power line to thereby reduce noise on the power line. A noise canceling means for canceling, and a peak value reduction provided at a position between the position where the noise detecting means is arranged on the power line and the position where the noise canceling means is arranged, and having an impedance for reducing the peak value of the passing noise. And an impedance element for use.

In the fourth power line noise filter of the present invention,
Noise on the power line is detected by detecting a current fluctuation or a voltage fluctuation on the power line by the noise detecting means, and a negative-phase signal, which is a signal having a phase opposite to the detected noise, is generated by the negative-phase signal generating means. Then, a change in current or voltage corresponding to the negative phase signal is applied to the power line by the noise canceling means, thereby canceling noise on the power line. Further, in this power line noise filter, the peak value of the noise on the power line on the noise canceling means is reduced by the peak value reducing impedance element, and the peak value of the noise on the power line on the noise detecting means side and the noise canceling means are reduced. The state in which the peak value of the noise on the power line on the side is different from that of the power line is maintained.

In the fourth power line noise filter of the present invention, the peak value reducing impedance element may include an inductor.

Further, the fourth power line noise filter of the present invention is further provided on a signal path from the noise detecting means to the noise canceling means via the negative phase signal generating means, and is inputted to the noise canceling means. 180 ° phase difference between noise and current or voltage change applied to the power line by the noise canceling means
, A phase adjustment impedance element having an impedance for adjusting the phase of the anti-phase signal may be provided. In this case, the phase adjustment impedance element may include an inductor.

[0036]

Embodiments of the present invention will be described below in detail with reference to the drawings. [First Embodiment] FIG. 1 is a block diagram showing a configuration of a power line noise filter according to a first embodiment of the present invention. The power line noise filter 10 according to the present embodiment
This is to reduce the current common mode noise on the power line 1. The power line 1 includes two conductive lines 1a and 1b. The power line 1 may transport AC power or may transport DC power.

The power line noise filter 10 includes a detection circuit 11 for detecting noise on the power line 1, an anti-phase signal generation circuit 12 for generating an anti-phase signal which is an anti-phase signal to the noise detected by the detection circuit 11. And an injection circuit 13 for injecting the negative-phase signal generated by the negative-phase signal generation circuit 12 into the power line 1. The detection circuit 11 is arranged at a position closer to the noise source than the injection circuit 13. Detection circuit 11
Corresponds to the noise detection means in the present invention. The anti-phase signal generation circuit 12 corresponds to the anti-phase signal generation means in the present invention. The injection circuit 13 corresponds to the noise canceling means in the present invention.

The detection circuit 11 detects noise on the power line 1 by detecting a change in current in the two conductive lines 1a and 1b of the power line 1. The detection circuit 11
Detects noise propagating through the two conductive lines 1a and 1b in the same phase. Therefore, the detection circuit 11 detects current common mode noise on the power line 1.

FIG. 1 shows an example of the configuration of the detection circuit 11. In this example, the detection circuit 11 includes a core surrounding the two conductive wires 1a and 1b, and a coil 1 wound around the core.
1c. In this detection circuit 11, the coil 11
The high-frequency component of the current fluctuation in the conductive lines 1a and 1b is detected by the current induced in c. The core is made of a magnetic material such as ferrite, permalloy, and amorphous. The detection circuit 11 includes a coil 11c
However, for example, a current sensor including a magnetic sensor for detecting a magnetic field generated by a current may be used. Examples of the magnetic sensor in this case include a magnetic sensor having a sensor head including a core made of a magnetic material such as ferrite, permalloy, and amorphous, and a coil wound on the core, and an MR sensor using a magnetoresistance effect.
(Magnetoresistance) GM using element or giant magnetoresistance effect
An R (giant magnetoresistance) element or the like can be used.

The injection circuit 13 applies a change in current corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 12 to the power line 1 to generate the power line 1 by the negative-phase signal generation circuit 12. Injected negative phase signal,
This cancels out noise on the power line 1. Further, the injection circuit 13 gives the same change in current corresponding to the negative-phase signal to the two conductive lines 1a and 1b in the power line 1.
Therefore, the injection circuit 13 cancels the current common mode noise on the power line 1.

FIG. 1 shows an example of the configuration of the injection circuit 13. In this example, the injection circuit 13 includes a core surrounding the two conductive wires 1a and 1b, and a coil 1 wound around the core.
3c. In this injection circuit 13, the coil 13
By passing a current through c, the same change in current corresponding to the negative-phase signal is applied to the conductive lines 1a and 1b.

FIG. 2 shows an anti-phase signal generating circuit 1 shown in FIG.
2 is a circuit diagram illustrating an example of a configuration of FIG. The anti-phase signal generation circuit 12 in this example has a transformer 15. One end of the primary winding of the transformer 15 is connected via a resistor 16 to one end of a coil 11c of the detection circuit 11. The other end of the primary winding of the transformer 15 and one end of the secondary winding of the transformer 15 are connected to the circuit ground (signal ground). The other end of the secondary winding of the transformer 15 is connected to one end of the coil 13c of the injection circuit 13. Coil 1
The other end of 1c and the other end of coil 13c are connected to the circuit ground. Negative-phase signal generation circuit 1 in this example
According to 2, the current corresponding to the noise detected by the coil 11c of the detection circuit 11 flows through the primary winding of the transformer 15, and the coil of the injection circuit 13 connected to the secondary winding of the transformer 15 accordingly. A current having a phase opposite to that of noise flows through 13c.

Next, the operation of the power line noise filter 10 according to the present embodiment will be described. In the power line noise filter 10, the detection circuit 11 detects current fluctuations in the conductive lines 1a and 1b of the power line 1, thereby detecting current common mode noise on the power line 1. Then, the anti-phase signal generation circuit 12 generates an anti-phase signal which is a signal having an anti-phase to the noise detected by the detection circuit 11. Further, the injection circuit 13 applies the same current change corresponding to the negative-phase signal to the two conductive lines 1a and 1b in the power line 1. This allows
The current common mode noise on the power line 1 is canceled.

As described above, the power line noise filter 10 according to the present embodiment detects noise on the power line 1, generates a reverse phase signal that is a signal of a phase opposite to the noise, and generates the reverse phase signal. Is injected into the power line 1 to cancel the noise and reduce the noise. Therefore, the power line noise filter 10 can ideally reduce noise regardless of the magnitude or frequency band of the noise.

In the power line noise filter 10 according to the present embodiment, noise on the power line 1 is detected by detecting a fluctuation in the current on the power line 1, and the current corresponding to the negative-phase signal is detected with respect to the power line 1. The noise on the power line 1 is canceled by giving the change. Therefore, the power line noise filter 10 does not amplify the noise voltage or convert the noise voltage into a current having the opposite phase, so that the delay of the opposite phase signal with respect to the noise and the difference of the waveform of the opposite phase signal with respect to the noise waveform are not caused. Can be reduced. Therefore, according to the power line noise filter 10, it is possible to cancel the noise as accurately as possible. According to the power line noise filter 10,
Since the delay of the reverse phase signal with respect to the noise can be reduced, not only continuous noise but also sudden noise can be canceled.

From the above, according to the power line noise filter 10 according to the present embodiment, it is possible to effectively reduce noise on the power line 1 in a wide frequency band, and if only continuous noise is used. Also, sudden noise can be effectively reduced.

The power line noise filter 10 according to the present embodiment works universally irrespective of the frequency band, magnitude and nature of noise. Therefore, the power line noise filter 10
When the filter is used, it is not necessary to optimize the filter according to the device that generates noise. Further, standardization of the power line noise filter 10 is easy.

Next, three usage examples of the power line noise filter 10 according to the present embodiment will be described with reference to FIGS.

FIG. 3 shows a first application example of the power line noise filter 10. The first use example is an example in which a power line noise filter 10 is installed in a power input portion of a device that is a noise generation source. In the system shown in FIG. 3, an electric / electronic device 112 is connected to the power line 1 via a switching power supply 111, and another electric / electronic device 113 is connected. In such a system, the switching power supply 111 is a noise generation source, and noise generated from the switching power supply 111 is transmitted to the electric / electronic device 113 via the power line 1 and may adversely affect the electric / electronic device 113. Examples of the electric / electronic devices 113 that are adversely affected by noise include audio / video devices, information devices, and medical devices.

Therefore, in the first application example, the power line noise filter 10 is provided at the power input portion of the switching power supply 111 which is a noise generation source. Accordingly, noise generated by the switching power supply 111 can be reduced, and noise on the power line 1 can be prevented from adversely affecting other electric / electronic devices 113 connected to the power line 1.

The first usage example shown in FIG. 3 can be applied to a power line communication system. That is, in FIG. 3, a power line communication system in which a plurality of devices including an electric / electronic device 113 are connected to the power line 1 as devices using power line communication is considered. In such a system, if the power line noise filter 10 is installed in the power input portion of the switching power supply 111 serving as a noise generation source, the noise generated by the switching power supply 111 is prevented from adversely affecting the communication using the power line 1. can do. This makes it possible to construct a stable communication environment.

FIG. 4 shows a second application example of the power line noise filter 10. The second use example is an example in which a power line noise filter 10 is installed in a power input portion of a device in which an adverse effect due to noise on a power line is to be eliminated. In the system shown in FIG. 4, a plurality of electric / electronic devices 121 and 1 for which it is desired to eliminate an adverse effect due to noise on the power line 1 are provided.
22 are connected. Therefore, in the second usage example, the power line noise filter 10 is installed in each of the power input portions of the devices 121 and 122. Thereby, the power line 1
It is possible to universally prevent the noise on the power line 1 from adversely affecting the devices 121 and 122 irrespective of the frequency band, magnitude and nature of the noise generated above. The second application example can be applied to a wide range of uses such as noise countermeasures in audio / video equipment, information equipment, medical equipment, and the like.

FIG. 5 shows a third application example of the power line noise filter 10. The third usage example is an example in which the power line noise filter 10 is used as a blocking filter in a power line communication system. In the system shown in FIG. 5, a plurality of devices 132 and 133 that perform power line communication are connected to an indoor power line 131 installed in a house 130. The indoor power line 131 and the outdoor power line 14
A blocking filter 135 is provided between the two. The blocking filter 135 is connected to the indoor power line 13.
1 is a filter that prevents a communication signal on the power line 1 from leaking to the outdoor power line 141 and prevents noise on the outdoor power line 141 from entering the indoor power line 131.

The blocking filter 135 has the power line noise filter 10 according to the present embodiment and a common mode choke coil 136 connected to the indoor side of the power line noise filter 10. Note that the common mode choke coil 136 is provided to increase the impedance with respect to the frequency of the communication signal in order to prevent attenuation of the communication signal in power line communication.

According to the third usage example, the indoor power line 131
The above communication signal can be prevented from leaking to the outdoor power line 141, and the noise on the outdoor power line 141 can be prevented from entering the indoor power line 131.

[Second Embodiment] FIG. 6 is a block diagram showing a configuration of a power line noise filter according to a second embodiment of the present invention. The power line noise filter 20 according to the present embodiment reduces voltage common mode noise on the power line 1.

The power line noise filter 20 includes a detection circuit 21 for detecting noise on the power line 1, an anti-phase signal generation circuit 22 for generating an anti-phase signal which is an anti-phase signal to the noise detected by the detection circuit 21. And an injection circuit 23 for injecting the reverse phase signal generated by the reverse phase signal generation circuit 22 into the power line 1. The detection circuit 21 is arranged at a position closer to the noise source than the injection circuit 23. Detection circuit 21
Corresponds to the noise detection means in the present invention. The anti-phase signal generation circuit 22 corresponds to the anti-phase signal generation means in the present invention. The injection circuit 23 corresponds to the noise canceling means in the present invention.

The detection circuit 21 detects noise on the power line 1 by detecting voltage fluctuations on the two conductive lines 1a and 1b of the power line 1. The detection circuit 21
Detects noise propagating through the two conductive lines 1a and 1b in the same phase. Therefore, the detection circuit 21 detects the voltage common mode noise on the power line 1.

FIG. 6 shows an example of the configuration of the detection circuit 21. In this example, the detection circuit 21 has one end connected to the conductive line 1a, the other end connected to the input end of the antiphase signal generation circuit 22, and one end connected to the conductive line 1b, The other end is the reverse-phase signal generation circuit 22
And a capacitor 21b connected to the input terminal of Capacitors 21a and 21b are each connected to conductive line 1
Among the voltage fluctuations in a and 1b, the high frequency component is passed, and the low frequency component including the frequency of the AC power is cut off.

The configuration of the antiphase signal generation circuit 22 is, for example,
The configuration is the same as the configuration of the anti-phase signal generation circuit 12 shown in FIG.

The injection circuit 23 generates a voltage change corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 22 to the power line 1 so that the power line 1 is generated by the negative-phase signal generation circuit 22. Injected negative phase signal,
This cancels out noise on the power line 1. Further, the injection circuit 23 gives the same voltage change corresponding to the negative-phase signal to the two conductive lines 1a and 1b in the power line 1.
Therefore, the injection circuit 23 cancels the voltage common mode noise on the power line 1.

FIG. 6 shows an example of the configuration of the injection circuit 23. In this example, the injection circuit 23 has one end connected to the output end of the reverse-phase signal generation circuit 22 and the other end connected to the conductive line 1a.
And a capacitor 23b having one end connected to the output end of the negative-phase signal generation circuit 22 and the other end connected to the conductive line 1b. In this example,
The injection circuit 23 is connected via capacitors 23a and 23b,
The same voltage change corresponding to the negative-phase signal is applied to conductive lines 1a and 1b.

Power line noise filter 2 according to the present embodiment
0, the detection circuit 21 causes the conductive lines 1a,
By detecting the voltage fluctuation in 1b, voltage common mode noise on the power line 1 is detected. Then, the anti-phase signal generation circuit 22 generates an anti-phase signal that is a signal of an anti-phase with the noise detected by the detection circuit 21. Further, the two conductive lines 1 are
The same voltage change corresponding to the negative phase signal is applied to a and 1b. Thereby, the common mode noise on the power line 1 is canceled out.

Power line noise filter 2 according to the present embodiment
In the case of 0, noise on the power line 1 is detected by detecting a fluctuation in the voltage on the power line 1, and the noise on the power line 1 is canceled by giving a voltage change corresponding to the negative-phase signal to the power line 1. Accordingly, the power line noise filter 20 does not amplify the noise voltage or convert the noise voltage into a current having the opposite phase, so that the delay of the negative-phase signal with respect to the noise and the difference in the waveform of the negative-phase signal with respect to the noise waveform are eliminated. Can be reduced. Therefore, the power line noise filter 2
According to 0, noise can be canceled as accurately as possible.

Other configurations, operations, and effects of the present embodiment are the same as those of the first embodiment. Also,
The usage example of the power line noise filter 10 described in the first embodiment can be applied to the power line noise filter 20 according to the present embodiment.

[Third Embodiment] FIG. 7 is a block diagram showing a configuration of a power line noise filter according to a third embodiment of the present invention. The power line noise filter 30 according to the present embodiment reduces current common mode noise and voltage common mode noise on the power line 1.

The power line noise filter 30 generates two detection circuits 31C and 31V for detecting noise on the power line 1, and generates a reverse phase signal which is a signal of a phase opposite to the noise detected by the detection circuits 31C and 31V, respectively. There are provided two negative-phase signal generating circuits 32C and 32V, and two injection circuits 33C and 33V for injecting the negative-phase signals generated by the negative-phase signal generating circuits 32C and 32V into the power line 1, respectively. The detection circuits 31C and 31V are provided with the injection circuits 33C and 33C.
It is arranged at a position closer to the noise source than V.

The detection circuit 31C corresponds to the first noise detection means in the present invention. The anti-phase signal generation circuit 32C corresponds to the first anti-phase signal generation means in the present invention. The injection circuit 33C corresponds to a first noise canceling unit in the present invention. The detection circuit 31V corresponds to a second noise detection unit in the present invention. The anti-phase signal generation circuit 32V corresponds to the second anti-phase signal generation means in the present invention. Injection circuit 33V
Corresponds to the second noise canceling means in the present invention.

The detection circuit 31C detects a current noise propagating through the two conductive lines 1a and 1b in the same phase by detecting a change in the current in the two conductive lines 1a and 1b of the power line 1. . Therefore, the detection circuit 31C detects the current mode common mode noise on the power line 1. The noise detected by the detection circuit 31C corresponds to the first noise in the present invention.

The detection circuit 31V has two conductive lines 1a and 1
By detecting the fluctuation of the voltage at the point b, voltage noise propagating in the same phase through the two conductive lines 1a and 1b is detected. Therefore, the detection circuit 31V detects the voltage common mode noise on the power line 1. The noise detected by the detection circuit 31V corresponds to the second noise in the present invention.

FIG. 7 shows an example of the configuration of the detection circuits 31C and 31V. In this example, the detection circuit 31C
It has a core surrounding the two conductive wires 1a and 1b, and a coil 31Cc wound around the core. One end of the coil 31Cc is connected to the input terminal of the reverse-phase signal generation circuit 32C, and the other end is connected to the circuit ground. The detection circuit 31C detects the high-frequency component of the current fluctuation in the conductive wires 1a and 1b by the current induced in the coil 31Cc. The detection circuit 31V has one end connected to the conductive line 1a, the other end connected to the input end of the negative-phase signal generation circuit 32V, one end connected to the conductive line 1b, and the other end generating the negative-phase signal. And a capacitor 31Vb connected to the input terminal of the circuit 32V. Capacitor 31
Va and 31Vb allow passage of high-frequency components and cut-off of low-frequency components including the frequency of AC power among the voltage fluctuations in the conductive lines 1a and 1b, respectively.

The anti-phase signal generation circuit 32 C
C generates a reverse-phase signal which is a signal having a phase opposite to that of the current common mode noise detected by C,
V generates an anti-phase signal which is an anti-phase signal to the voltage common mode noise detected by the detection circuit 31V.
The negative phase signal generated by the negative phase signal generation circuit 32C corresponds to the first negative phase signal in the present invention. Negative phase signal generation circuit 3
The negative-phase signal at which 2V is generated corresponds to the second negative-phase signal in the present invention. The configuration of the negative-phase signal generation circuits 32C and 32V is, for example, the same as the configuration of the negative-phase signal generation circuit 12 shown in FIG.

The injection circuit 33C applies the same change in current corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 32C to the two conductive lines 1a and 1b of the power line 1 so that the power line 1 Phase signal generation circuit 32
The negative phase signal generated by C is injected to cancel the current common mode noise on the power line 1. The injection circuit 33V applies the same voltage change corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 32V to the two conductive lines 1a and 1b of the power line 1, thereby providing the power line 1 with the same voltage. The negative-phase signal generated by the negative-phase signal generation circuit 32V is injected, thereby canceling voltage common mode noise on the power line 1.

FIG. 7 shows an example of the configuration of the injection circuits 33C and 33V. In this example, the injection circuit 33C
It has a core surrounding the two conductive wires 1a and 1b, and a coil 33Cc wound around the core. One end of the coil 33Cc is connected to the output terminal of the reverse-phase signal generation circuit 32C, and the other end is connected to the circuit ground. In this example, the injection circuit 33C causes the current to flow through the coil 33Cc, thereby causing the negative-phase signal generation circuit 32
The same current change corresponding to the opposite-phase signal generated by C is given.

In this example, the injection circuit 33V includes a capacitor 33Va having one end connected to the output terminal of the negative-phase signal generation circuit 32V and the other end connected to the conductive line 1a, and one end having the negative-phase signal generation circuit. A capacitor 33Vb is connected to the output terminal of 32V and the other end is connected to the conductive line 1b. In this example, the injection circuit 33V is
Via Va, 33Vb, the conductive lines 1a, 1b
The same voltage change corresponding to the reverse phase signal generated by the reverse phase signal generation circuit 32V is applied.

Power line noise filter 3 according to the present embodiment
0, the detection circuit 31C detects the conductive line 1 of the power line 1
a, 1b by detecting the variation of the current in
A current common mode noise on the power line 1 is detected. In addition, the detection circuit 31V detects the conductive line 1 of the power line 1.
a, 1b by detecting the voltage fluctuations,
Voltage common mode noise on the power line 1 is detected.

Then, the negative-phase signal generating circuit 32C generates a negative-phase signal which is a signal having a phase opposite to that of the current common mode noise detected by the detection circuit 31C.
In addition, the detection circuit 31
An anti-phase signal is generated which is an anti-phase signal to the voltage common mode noise detected by V.

Further, the same change in current corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 32C is applied to the two conductive lines 1a and 1b by the injection circuit 33C. Further, the same voltage change corresponding to the reverse-phase signal generated by the reverse-phase signal generation circuit 32V is given by the injection circuit 33V. As a result, the current common mode noise and the voltage common mode noise on the power line 1 are canceled.

Power line noise filter 3 according to the present embodiment
In the case of 0, current fluctuation on the power line 1 is detected by detecting a fluctuation of the current in the power line 1, and a change in current corresponding to a negative-phase signal having a reverse phase to the current noise is given to the power line 1. This cancels out the current noise on the power line 1. In addition, the power line noise filter 30 detects voltage noise on the power line 1 by detecting a voltage fluctuation on the power line 1 and detects a voltage change corresponding to a negative-phase signal having an opposite phase to the voltage noise. Is applied to the power line 1 to cancel the voltage noise on the power line 1.
Therefore, the power line noise filter 30 does not amplify the noise voltage or convert the noise voltage into a current having the opposite phase, so that the delay of the negative-phase signal with respect to the noise and the difference in the waveform of the negative-phase signal with respect to the noise waveform are eliminated. Can be reduced. Therefore, according to the power line noise filter 30, it is possible to cancel the noise as accurately as possible.

The other structures, operations and effects of the present embodiment are the same as those of the first embodiment. Also,
The usage example of the power line noise filter 10 described in the first embodiment can be applied to the power line noise filter 30 according to the present embodiment.

[Fourth Embodiment] FIG. 8 is a block diagram showing a configuration of a power line noise filter according to a fourth embodiment of the present invention. The power line noise filter 40 according to the present embodiment reduces current normal mode noise and current common mode noise on the power line 1.

The power line noise filter 40 is connected to the power line 1
Detection circuit 4 for detecting each noise on the conductive lines 1a and 1b
1 and two opposite-phase signal generation circuits 42 that generate an opposite-phase signal that is a signal that is opposite in phase to the noise detected by the detection circuit 41.
a, 42b, and an injection circuit 43 for injecting the negative-phase signal generated by the negative-phase signal generation circuits 42a, 42b into the conductive lines 1a, 1b. The detection circuit 41 is arranged at a position closer to the noise source than the injection circuit 43. The detection circuit 41 corresponds to the noise detection means in the present invention.
The negative phase signal generation circuits 42a and 42b correspond to the negative phase signal generation means in the present invention. The injection circuit 43 corresponds to the noise canceling means in the present invention.

The detection circuit 41 detects a change in the current in each of the conductive lines 1a and 1b, thereby detecting the conductive lines 1a and 1b.
1b is detected for each of the conductive lines 1a and 1b. Accordingly, the detection circuit 41 detects current-mode normal mode noise on the power line 1.

FIG. 8 shows an example of the configuration of the detection circuit 41. In this example, the detection circuit 41 includes a core surrounding the conductive wire 1a, a coil 41a wound around the core, a core surrounding the conductive wire 1b, and a coil 41b wound around the core.
And One end of the coil 41a is connected to the input terminal of the reverse phase signal generation circuit 42a, and the other end is connected to the circuit ground. One end of the coil 41b is connected to the input terminal of the reverse phase signal generation circuit 42b, and the other end is connected to the circuit ground. In this detection circuit 41, a coil 41a
The high-frequency component of the current variation in the conductive line 1a is detected by the current induced in the conductive line 1a, and the high-frequency component of the current variation in the conductive line 1b is detected by the current induced in the coil 41b.

The anti-phase signal generation circuit 42a includes a detection circuit 41
Generates a signal having a phase opposite to the noise on the conductive line 1a detected by the detection circuit 41. The negative-phase signal generation circuit 42b outputs a signal having a phase opposite to the noise on the conductive line 1b detected by the detection circuit 41. A negative-phase signal is generated. Negative phase signal generation circuit 42
The configurations of a and 42b are the same as, for example, the configuration of the antiphase signal generation circuit 12 shown in FIG.

The injection circuit 43 applies a change in current corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 42a to the conductive line 1a, so that the negative-phase signal generation circuit 42a To cancel the noise on the conductive line 1a. Further, the injection circuit 43 provides the conductive line 1b with a change in current corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 42b, so that the negative-phase signal generation circuit 42b applies the current to the conductive line 1b. Inject the generated out-of-phase signal,
This cancels out noise on the conductive line 1b. Therefore, the injection circuit 43 cancels the noise in the normal mode of the current on the power line 1.

FIG. 8 shows an example of the configuration of the injection circuit 43. In this example, the injection circuit 43 includes a core surrounding the conductive wire 1a, a coil 43a wound around the core, a core surrounding the conductive wire 1b, and a coil 43b wound around the core.
And One end of the coil 43a is connected to the output terminal of the reverse-phase signal generation circuit 42a, and the other end is connected to the circuit ground. One end of the coil 43b is connected to the output terminal of the reverse phase signal generation circuit 42b, and the other end is connected to the circuit ground. In this example, the injection circuit 43 supplies a current to each of the coils 43a and 43b,
A change in current corresponding to each of the negative-phase signals generated by the negative-phase signal generation circuits 42a and 42b is applied to the conductive lines 1a and 1b.

Power line noise filter 4 according to the present embodiment
0, the detection circuit 41 causes the conductive lines 1a,
By detecting a change in current in each of the conductive lines 1b, noise generated in each of the conductive lines 1a and 1b is detected for each of the conductive lines 1a and 1b. As a result, noise in the current normal mode on the power line 1 is detected. And
The detection circuit 4 is controlled by the antiphase signal generation circuits 42a and 42b.
A negative-phase signal is generated for each of the conductive lines 1a and 1b, which is a signal having a phase opposite to that of the noise for each of the conductive lines 1a and 1b detected by 1. Further, the two conductive lines 1 are
For each of the conductive lines 1a and 1b, a change in current corresponding to the negative-phase signal for each of the conductive lines 1a and 1b is given. This allows
Current mode normal mode noise on the power line 1 is canceled. Further, in the present embodiment, since the noise on the conductive lines 1a and 1b is individually detected and canceled, the current common mode noise on the power line 1 is also canceled.

Power line noise filter 4 according to the present embodiment
At 0, the noise on the power line 1 is detected by detecting the fluctuation of the current in the power line 1, and the noise on the power line 1 is canceled by giving the power line 1 a change in current corresponding to the negative-phase signal. Therefore, the power line noise filter 40 does not amplify the noise voltage or convert the noise voltage into a current having the opposite phase, so that the delay of the negative-phase signal with respect to the noise and the difference in the waveform of the negative-phase signal with respect to the noise waveform. Can be reduced. Therefore, the power line noise filter 4
According to 0, noise can be canceled as accurately as possible.

The other configurations, operations, and effects of the present embodiment are the same as those of the first embodiment. Also,
The usage example of the power line noise filter 10 described in the first embodiment can be applied to the power line noise filter 40 according to the present embodiment.

[Fifth Embodiment] FIG. 9 is a block diagram showing a configuration of a power line noise filter according to a fifth embodiment of the present invention. The power line noise filter 50 according to the present embodiment reduces voltage normal mode noise and voltage common mode noise on the power line 1.

The power line noise filter 50 is connected to the power line 1
Detection circuit 5 for detecting each noise on the conductive lines 1a and 1b
1 and two opposite-phase signal generation circuits 52 that generate an opposite-phase signal that is a signal of the opposite phase to the noise detected by the detection circuit 51.
a, 52b, and an injection circuit 53 for injecting the negative-phase signal generated by the negative-phase signal generation circuits 52a, 52b into the conductive lines 1a, 1b. The detection circuit 51 is arranged at a position closer to the noise source than the injection circuit 53. The detection circuit 51 corresponds to a noise detection unit in the present invention.
The anti-phase signal generation circuits 52a and 52b correspond to anti-phase signal generation means in the present invention. The injection circuit 53 corresponds to the noise canceling means in the present invention.

The detection circuit 51 detects a change in the voltage of each of the conductive lines 1a and 1b, thereby detecting the conductive lines 1a and 1b.
1b is detected for each of the conductive lines 1a and 1b. Therefore, the detection circuit 51 detects the noise of the voltage normal mode on the power line 1.

FIG. 9 shows an example of the configuration of the detection circuit 51. In this example, the detection circuit 51 includes a capacitor 51a having one end connected to the conductive line 1a and the other end connected to the input end of the negative-phase signal generation circuit 52a, and one end connected to the conductive line 1b.
And a capacitor 51b whose other end is connected to the input terminal of the reverse-phase signal generation circuit 52b. Capacitors 51a and 51b allow high-frequency components of voltage fluctuations in conductive lines 1a and 1b, respectively, and block low-frequency components including the frequency of AC power.

The anti-phase signal generation circuit 52a includes a detection circuit 51
Generates a signal having a phase opposite to the noise on the conductive line 1a detected by the detection circuit 51. The antiphase signal generation circuit 52b outputs a signal having a phase opposite to the noise on the conductive line 1b detected by the detection circuit 51. A negative-phase signal is generated. Negative phase signal generation circuit 52
The configurations of a and 52b are the same as, for example, the configuration of the anti-phase signal generation circuit 12 shown in FIG.

The injection circuit 53 applies a change in voltage corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 52a to the conductive line 1a, so that the negative-phase signal generation circuit 52a To cancel the noise on the conductive line 1a. The injection circuit 53 applies a voltage change corresponding to the negative-phase signal generated by the negative-phase signal generation circuit 52b to the conductive line 1b, so that the negative-phase signal generation circuit 52b Inject the generated out-of-phase signal,
This cancels out noise on the conductive line 1b. Therefore, the injection circuit 53 cancels the noise in the voltage normal mode on the power line 1.

FIG. 9 shows an example of the configuration of the injection circuit 53. In this example, one end of the injection circuit 53 is connected to the output end of the reverse-phase signal generation circuit 52a, and the other end is connected to the conductive line 1.
a, and a capacitor 53b having one end connected to the output end of the negative-phase signal generation circuit 52b and the other end connected to the conductive line 1b. In this example, the injection circuit 53 applies a change in the voltage corresponding to each of the negative-phase signals generated by the negative-phase signal generation circuits 52a and 52b to the conductive lines 1a and 1b via the capacitors 53a and 53b. give.

Power line noise filter 5 according to the present embodiment
0, the detection circuit 51 causes the conductive lines 1a, 1a,
By detecting voltage fluctuations in each of the conductive lines 1b, noise generated in each of the conductive lines 1a and 1b is detected for each of the conductive lines 1a and 1b. As a result, noise in the voltage normal mode on the power line 1 is detected. And
The detection circuit 5 is provided by the antiphase signal generation circuits 52a and 52b.
A negative-phase signal is generated for each of the conductive lines 1a and 1b, which is a signal having a phase opposite to that of the noise for each of the conductive lines 1a and 1b detected by 1. Further, the two conductive lines 1 are
A change in voltage corresponding to the negative-phase signal for each of the conductive lines 1a and 1b is applied to each of the conductive lines 1a and 1b. This allows
The noise in the voltage normal mode on the power line 1 is canceled. Further, in the present embodiment, since noise on the conductive lines 1a and 1b is individually detected and canceled out, the voltage common mode noise on the power line 1 is also canceled out.

Power line noise filter 5 according to the present embodiment
In the case of 0, noise on the power line 1 is detected by detecting a fluctuation in the voltage on the power line 1, and the noise on the power line 1 is canceled by giving a voltage change corresponding to the negative-phase signal to the power line 1. Therefore, the power line noise filter 50 does not amplify the noise voltage or convert the noise voltage into a current having the opposite phase, so that the delay of the negative-phase signal with respect to the noise and the difference in the waveform of the negative-phase signal with respect to the noise waveform are eliminated. Can be reduced. Therefore, the power line noise filter 5
According to 0, noise can be canceled as accurately as possible.

Other configurations, operations and effects of the present embodiment are the same as those of the first embodiment. Also,
The usage example of the power line noise filter 10 described in the first embodiment can be applied to the power line noise filter 50 according to the present embodiment.

[Sixth Embodiment] FIG. 10 is a block diagram showing a configuration of a power line noise filter according to a sixth embodiment of the present invention. The power line noise filter 60 according to the present embodiment reduces current normal mode noise, voltage normal mode noise, current common mode noise, and voltage common mode noise on the power line 1. Things.

The power line noise filter 60 is connected to the power line 1
A detection circuit 61C for detecting each current noise on the conductive lines 1a and 1b, a detection circuit 61V for detecting each voltage noise on the conductive lines 1a and 1b, and each of the detection circuits 61C Two opposite-phase signal generation circuits 62Ca and 62Cb for generating opposite-phase signals that are signals opposite in phase to noise, and two opposite-phase signals for generating signals that are opposite in phase to each noise detected by the detection circuit 61V. Negative phase signal generation circuit 62Va, 6
2Vb, an injection circuit 63C for injecting the negative-phase signal generated by the negative-phase signal generation circuits 62Ca and 62Cb into the conductive lines 1a and 1b, and negative-phase signal generation circuits 62Va and 62Vb into the conductive lines 1a and 1b. And an injection circuit 63V for injecting the opposite-phase signal generated by the above. The detection circuits 61C and 61V are arranged at positions closer to the noise source than the injection circuits 63C and 63V.

The detecting circuit 61C corresponds to the first noise detecting means in the present invention. Negative-phase signal generation circuits 62Ca, 6
2Cb corresponds to the first anti-phase signal generation means in the present invention. The injection circuit 63C corresponds to the first noise canceling means in the present invention. The detection circuit 61V is the second circuit of the present invention.
Corresponds to the noise detecting means. Reverse phase signal generation circuit 62V
“a” and “62Vb” correspond to the second anti-phase signal generation means in the present invention. The injection circuit 63V corresponds to the second noise canceling means in the present invention.

The detection circuit 61C detects current fluctuations in the two conductive lines 1a and 1b of the power line 1 to detect current noise generated in each of the two conductive lines 1a and 1b. Detection is performed for each of 1a and 1b. Therefore, the detection circuit 61C detects the normal mode noise on the power line 1 in the current mode. The noise detected by the detection circuit 61C corresponds to the first noise in the present invention.

The detection circuit 61V includes two conductive lines 1a, 1a
By detecting the voltage fluctuation at b, the voltage noise generated in each of the two conductive lines 1a and 1b is detected for each of the conductive lines 1a and 1b. Therefore, the detection circuit 61V
Will detect noise in the voltage normal mode on the power line 1. The noise detected by the detection circuit 61V corresponds to the second noise in the present invention.

FIG. 10 shows an example of the configuration of the detection circuits 61C and 61V. In this example, the detection circuit 61C
Has a core surrounding the conductive wire 1a, a coil 61Ca wound around the core, a core surrounding the conductive wire 1b, and a coil 61Cb wound around the core. Coil 61Ca
Is connected to the input terminal of the reverse-phase signal generation circuit 62Ca, and the other end is connected to the ground of the circuit. Coil 6
One end of 1Cb is connected to the input end of the reverse-phase signal generation circuit 62Cb, and the other end is connected to the circuit ground. The detection circuit 61C detects a high-frequency component of the current variation in the conductive wire 1a by the current induced in the coil 61Ca, and detects the high-frequency component of the current variation in the conductive wire 1b by the current induced in the coil 61Cb. Detect high frequency components.

In this example, the detection circuit 61V has one end connected to the conductive line 1a and the other end connected to the negative-phase signal generation circuit 6.
A capacitor 61Va connected to the input terminal of 2Va, one end connected to the conductive line 1b, and the other end
And a capacitor 61Vb connected to the 2Vb input terminal. Capacitors 61Va and 61Vb allow high-frequency components of voltage fluctuations in conductive lines 1a and 1b to pass, and block low-frequency components including the frequency of AC power.

The anti-phase signal generation circuit 62Ca includes the detection circuit 6
1C generates a reverse-phase signal which is a signal opposite in phase to the current noise on the conductive line 1a detected by 1C. The negative-phase signal generation circuit 62Cb is connected to the conductive line 1 detected by the detection circuit 61C.
A negative-phase signal which is a signal having a phase opposite to that of the current noise on b is generated. The negative-phase signal generation circuit 62Va generates a negative-phase signal that is a signal that is in phase with the voltage noise on the conductive line 1a detected by the detection circuit 61V. Reverse phase signal generation circuit 62V
b generates an anti-phase signal which is an anti-phase signal to the voltage noise on the conductive line 1b detected by the detection circuit 61V.
Each negative-phase signal generated by the negative-phase signal generation circuits 62Ca and 62Cb corresponds to the first negative-phase signal in the present invention. Each negative-phase signal generated by the negative-phase signal generation circuits 62Va and 62Vb corresponds to the second negative-phase signal in the present invention. The configuration of the reverse-phase signal generation circuits 62Ca, 62Cb, 62Va, and 62Vb is, for example, the same as the configuration of the reverse-phase signal generation circuit 12 shown in FIG.

Injection circuit 63C applies antiphase signal generation circuits 62Ca and 62Cb to conductive lines 1a and 1b, respectively.
Is applied to each of the conductive lines 1a and 1b, thereby injecting each of the negative-phase signals generated by the negative-phase signal generating circuits 62Ca and 62Cb into the conductive lines 1a and 1b. The current noise on the lines 1a and 1b is canceled. Therefore, the injection circuit 63 cancels the normal mode noise on the power line 1.

Injection circuit 63V is connected to conductive lines 1a and 1b, respectively, to generate opposite-phase signal generation circuits 62Va and 62Vb.
Is applied to each of the conductive lines 1a and 1b, thereby injecting each of the negative-phase signals generated by the negative-phase signal generating circuits 62Va and 62Vb into the conductive lines 1a and 1b. The voltage noise on the lines 1a and 1b is canceled. Therefore, the injection circuit 63V is connected to the power line 1
This cancels out the above-mentioned normal mode noise of the voltage type.

FIG. 10 shows an example of the configuration of the injection circuits 63C and 63V. In this example, the injection circuit 63C
Has a core surrounding the conductive wire 1a, a coil 63Ca wound around the core, a core surrounding the conductive wire 1b, and a coil 63Cb wound around the core. Coil 63Ca
Is connected to the output terminal of the reverse phase signal generation circuit 62Ca, and the other end is connected to the ground of the circuit. Coil 6
One end of 3Cb is connected to the output end of the reverse-phase signal generation circuit 62Cb, and the other end is connected to the circuit ground. In this example, the injection circuit 63C includes coils 63Ca and 63Cb.
Of the conductive lines 1a, 1
b, the negative-phase signal generation circuits 62Ca, 62
A change in current corresponding to each negative-phase signal generated from Cb is given.

In this example, the injection circuit 63V has a capacitor 63Va having one end connected to the output terminal of the negative-phase signal generation circuit 62Va and the other end connected to the conductive line 1a, and one end having the negative-phase signal generation circuit. It has a capacitor 63Vb connected to the output terminal of 62Vb and the other end connected to the conductive line 1b. In this example, the injection circuit 63V applies, to the conductive lines 1a and 1b via the capacitors 63Va and 63Vb, changes in voltages corresponding to the respective negative-phase signals generated by the negative-phase signal generation circuits 62Va and 62Vb, respectively. give.

Power line noise filter 6 according to the present embodiment
0, the detection circuit 61C detects the conductive line 1 of the power line 1
By detecting the fluctuation of the current in each of the conductive lines 1a and 1b, the current noise generated in each of the conductive lines 1a and 1b is detected for each of the conductive lines 1a and 1b. As a result, noise in the current normal mode on the power line 1 is detected. In addition, the detection circuit 61V detects the conductive line 1 of the power line 1.
By detecting voltage fluctuations in each of the conductive lines 1a and 1b, voltage noise generated in each of the conductive lines 1a and 1b is detected for each of the conductive lines 1a and 1b. As a result, noise in the voltage normal mode on the power line 1 is detected.

Then, the reverse phase signal generation circuits 62Ca, 62
Cb generates a negative-phase signal for each of the conductive lines 1a and 1b, which is a signal having a phase opposite to that of the current noise of each of the conductive lines 1a and 1b detected by the detection circuit 61C. Further, the detection circuit 6 is provided by the reverse phase signal generation circuits 62Va and 62Vb.
A negative-phase signal is generated for each of the conductive lines 1a and 1b, which is a signal having a phase opposite to the voltage noise of each of the conductive lines 1a and 1b detected by 1V.

Further, the injection circuit 63C applies an anti-phase signal generation circuit 62 to each of the two conductive lines 1a and 1b.
A change in current corresponding to a negative-phase signal for each conductive line 1a, 1b generated by Ca, 62Cb is given. Also,
The injection circuit 63V changes the voltage of each of the two conductive lines 1a and 1b in accordance with the negative-phase signal of each of the conductive lines 1a and 1b generated by the negative-phase signal generating circuits 62Va and 62Vb. Can be As a result, the noise in the normal mode of the current and the noise in the normal mode of the voltage on the power line 1 are canceled. In the present embodiment,
Since the noise on the conductive lines 1a and 1b is individually detected and canceled out, the current common mode noise and the voltage common mode noise on the power line 1 are also canceled.

Power line noise filter 6 according to the present embodiment
In the case of 0, current fluctuation on the power line 1 is detected by detecting a fluctuation of the current in the power line 1, and a change in current corresponding to a negative-phase signal having a reverse phase to the current noise is given to the power line 1. This cancels out the current noise on the power line 1. The power line noise filter 60 detects a voltage noise on the power line 1 by detecting a voltage fluctuation on the power line 1, and detects a voltage change corresponding to a reverse phase signal having a phase opposite to the voltage noise. Is applied to the power line 1 to cancel the voltage noise on the power line 1.
Accordingly, the power line noise filter 60 does not amplify the noise voltage or convert the noise voltage into a current having the opposite phase, so that the delay of the negative-phase signal with respect to the noise and the difference in the waveform of the negative-phase signal with respect to the noise waveform. Can be reduced. Therefore, according to the power line noise filter 60, noise can be canceled as accurately as possible.

Other configurations, operations and effects of the present embodiment are the same as those of the first embodiment. Also,
The usage example of the power line noise filter 10 described in the first embodiment can be applied to the power line noise filter 60 according to the present embodiment.

[Seventh Embodiment] FIG. 11 is a block diagram showing a configuration of a power line noise filter according to a seventh embodiment of the present invention. The power line noise filter 70 according to the present embodiment reduces current normal mode noise and current common mode noise on the power line 1, as in the fourth embodiment. In the present embodiment, the detection circuit and the injection circuit each constitute a part of the anti-phase signal generation circuit.

The power line noise filter 70 includes a detection circuit 71A for detecting noise on the conductive line 1a of the power line 1, and a reverse-phase signal which is a signal of a phase opposite to the noise detected by the detection circuit 71A for the conductive line 1a. An injection circuit 73A for injecting
An anti-phase signal generation circuit 72A including a detection circuit 71A and an injection circuit 73A is provided. The detection circuit 71A is arranged at a position closer to the noise source than the injection circuit 73A.
The detection circuit 71A corresponds to the noise detection means in the present invention. The anti-phase signal generation circuit 72A corresponds to the anti-phase signal generation means in the present invention. The injection circuit 73A corresponds to the noise canceling means in the present invention.

The detection circuit 71A has a transformer 71T including a primary winding and a secondary winding, and a capacitor 74 having one end connected to one end of the secondary winding of the transformer 71T. In the transformer 71T, the primary winding is connected in series to the conductive line 1a. Further, the injection circuit 73A
Has a transformer 73T including a primary winding and a secondary winding. In this transformer 73T, the primary winding is connected in series to the conductive line 1a. Capacitor 74
Is connected to one end of a secondary winding of the transformer 73T. The other end of the secondary winding of the transformer 71T and the other end of the secondary winding of the transformer 73T are grounded. Here, the secondary winding of the transformer 71T and the secondary winding of the transformer 73T are arranged such that the change in the current in the primary winding of the transformer 73T is opposite in phase to the change in the current in the primary winding of the transformer 71T. It is connected.

In the detection circuit 71A, a current is induced in the secondary winding of the transformer 71T due to the fluctuation of the current in the primary winding of the transformer 71T connected to the conductive line 1a.
A high-frequency component, that is, a noise component, of the current induced in the secondary winding of the transformer 71T passes through the capacitor 74 and is output from the detection circuit 71A. Thus, detection circuit 71A detects noise on conductive line 1a.

The current output from the detection circuit 71A flows through the secondary winding of the transformer 73T in the injection circuit 73A, and as a result, a current is induced in the primary winding of the transformer 73T. The current induced in the primary winding of the transformer 73T has a phase opposite to that of the noise detected by the detection circuit 71A. Thus, the injection circuit 73A is connected to the conductive line 1a.
Cancels the upper current normal mode noise.

In power line noise filter 70 according to the present embodiment, detection circuit 71A, injection circuit 73A, and negative-phase signal generation circuit 72A provided for conductive line 1a are provided.
A detection circuit, an injection circuit, and a negative-phase signal generation circuit having exactly the same configuration as those described above are also provided for the conductive line 1b of the power line 1.

According to the present embodiment, detection circuit 71A and injection circuit 73A are provided with opposite-phase signal generation circuit 72, respectively.
A of the power line noise filter 70
Is simplified.

Other structures, operations and effects of the present embodiment are the same as those of the fourth embodiment. Also,
The usage example of the power line noise filter 10 described in the first embodiment can be applied to the power line noise filter 70 according to the present embodiment.

[Eighth Embodiment] Next, an eighth embodiment of the present invention will be described.
The power line noise filter according to the embodiment will be described. FIG. 12 is a block diagram showing a basic configuration of the power line noise filter according to the present embodiment. The power line noise filter 80 according to the present embodiment is arranged at a predetermined position on the power line 1 and detects the noise on the power line 1
1, an anti-phase signal generation circuit 82 that generates an anti-phase signal that is an anti-phase signal to the noise detected by the detection circuit 81, and a power line 1 that is disposed at a different position from the detection circuit 81. And an injection circuit 83 for injecting a reverse-phase signal generated by the reverse-phase signal generation circuit 82, and a position between the position where the detection circuit 81 is disposed and the position where the injection circuit 83 is disposed on the power line 1. , And an impedance element 84 having an impedance for reducing the peak value of the passing noise. The detection circuit 81 is arranged at a position closer to the noise source than the injection circuit 83. The detection circuit 81 corresponds to the noise detection means in the present invention. The anti-phase signal generation circuit 82 corresponds to the anti-phase signal generation means in the present invention. The injection circuit 83 corresponds to the noise canceling means in the present invention. The impedance element 84 corresponds to the peak value reducing impedance element in the present invention.

In the power line noise filter 80 shown in FIG. 12, the configuration other than the impedance element 84 may be any of the configurations of the first to seventh embodiments.

The impedance of the impedance element 84 is sufficiently small so as not to hinder the power transport at the frequency of the power transported by the power line 1, and large enough to reduce the peak value of the noise in the noise frequency band. ing. As such an impedance element 84, for example, an inductor can be used.

Next, the operation of the power line noise filter 80 shown in FIG. 12 will be described. In the power line noise filter 80, an impedance element 84 is inserted in the power line 1 between the detection circuit 81 and the injection circuit 83. Therefore, the detection circuit 8 is more than the impedance element 84.
1 power line 1 (hereinafter simply power line 1 on detection circuit 81 side).
Say ) Is generated by the impedance element 8
4 and flows into the power line 1 on the injection circuit 83 side (hereinafter simply referred to as the power line 1 on the injection circuit 83 side) from the impedance element 84, the noise wave on the power line 1 on the injection circuit 83 side The high value is smaller than the peak value of the noise on the power line 1 on the detection circuit 81 side. In the present embodiment, the impedance element 84 is provided so that the peak value of the noise on the power line 1 on the detection circuit 81 side and the injection circuit 83
It is possible to maintain a state where the peak value of the noise on the power line 1 on the side is different.

In the power line noise filter 80 shown in FIG. 12, the detection circuit 81 detects noise on the power line 1. Then, the reverse-phase signal generation circuit 82 generates a reverse-phase signal which is a signal having a reverse phase to the noise detected by the detection circuit 81. Further, the reverse phase signal generated by the reverse phase signal generation circuit 82 is injected into the power line 1 by the injection circuit 83. Thereby, the noise on the power line 1 on the side of the injection circuit 83 is canceled.

In this embodiment, the peak value of noise after passing through impedance element 84 is smaller than the peak value of noise before passing through impedance element 84. Therefore, in the present embodiment, the peak value of the negative-phase signal injected into the power line 1 by the injection circuit 83 is close to the peak value of the noise input to the injection circuit 83 after passing through the impedance element 84. Need to be adjusted.

As described above, according to the present embodiment, the synergistic effect of the effect of reducing the noise by the impedance element 84 and the effect of reducing the noise by injecting the opposite-phase signal causes the power line on the injection circuit 83 side. 1 can be reduced. Further, according to the present embodiment, since the peak value of the noise on the power line 1 on the detection circuit 81 side and the peak value of the noise on the power line 1 on the injection circuit 83 side can be maintained different, In the power line 1 on the circuit 83 side, a state where the peak value of the noise is small can be stably maintained. Therefore, according to the present embodiment,
Effectively, noise on the power line 1 on the side of the injection circuit 83 can be reduced.

By the way, the noise input to the injection circuit 83 and the change of the current or voltage applied to the power line 1 by the injection circuit 83, that is, the power line 1
Ideally, the phase difference between the signal and the inverted signal is 180 °. However, in the present embodiment, since the impedance element 84 is provided in the middle of the power line 1 between the detection circuit 81 and the injection circuit 83, the phase of noise may change before and after passing through the impedance element 84. Therefore, the power line noise filter 8 shown in FIG.
0, the noise input to the injection circuit 83 and the injection circuit 83
The phase difference with the opposite phase signal injected into the power line 1 is 1
It may deviate greatly from 80 °. In such a case, an impedance element having an impedance for adjusting the phase of the negative-phase signal may be inserted into a signal path from the detection circuit 81 to the injection circuit 83 via the negative-phase signal generation circuit 82.

FIG. 13 shows a signal path from the detection circuit 81 to the injection circuit 83 via the antiphase signal generation circuit 82.
FIG. 3 is a block diagram showing a configuration of a power line noise filter 80 in which an impedance element for phase adjustment is inserted. In this power line noise filter 80, an impedance element 85 is inserted between an antiphase signal generation circuit 82 and an injection circuit 83. The impedance element 85 adjusts the phase of the negative-phase signal so that the phase difference between the noise input to the injection circuit 83 and the negative-phase signal injected into the power line 1 by the injection circuit 83 approaches 180 °. . In addition, the impedance element 85 can adjust the peak value of the reverse-phase signal injected into the power line 1 by the injection circuit 83 so as to approach the peak value of the noise input to the injection circuit 83. The impedance element 85 corresponds to the phase adjustment impedance element in the present invention.

Here, as shown in FIG. 13, the path of a signal passing through the detection circuit 81, the impedance element 84, and the injection circuit 83 is called a path X, and the detection circuit 81, the antiphase signal generation circuit 82, the impedance element A path of a signal passing through the path 85 and the injection circuit 83 is referred to as a path Y. The impedance of the impedance element 85 is set such that the phase difference between the signal passing through the path X and the signal passing through the path Y approaches 180 °. The impedance element 8
5 is provided, the antiphase signal generation circuit 82 adjusts the phase difference between the signal passing through the path X and the signal passing through the path Y by 180 °.
May be provided.

According to the power line noise filter 80 shown in FIG.
The phase difference with the opposite phase signal injected into the power line 1 by 1
At the same time, the peak value of the negative-phase signal injected into the power line 1 by the injection circuit 83 can be approximated to the peak value of the noise input to the injection circuit 83. Therefore, according to the power line noise filter 80,
More effectively, noise on the power line 1 on the side of the injection circuit 83 can be reduced. Other functions and effects of the power line noise filter 80 shown in FIG. 13 are the same as those of the power line noise filter 80 shown in FIG.

Next, referring to FIG. 14, a preferred relationship between the phase and the peak value of the noise input to injection circuit 83 and the phase and the peak value of the reverse phase signal injected into power line 1 by injection circuit 83 will be described. explain. FIG. 14 is a vector diagram that represents the noise input to the injection circuit 83, the reverse-phase signal injected into the power line 1 by the injection circuit 83, and the synthesized signal obtained by synthesizing these, as vectors. As shown in FIG. 14, the magnitude of the noise vector input to the injection circuit 83 is 1, and the magnitude of the vector of the reverse-phase signal injected into the power line 1 by the injection circuit 83 is A.
(A ≧ 0), and the shift of the phase of the vector of the antiphase signal with respect to the phase of the vector of the noise is φ (0 ° ≦ φ ≦ 360 °). Also, the magnitude of the vector of the combined signal of the noise and the inverted signal is B. Furthermore, the vector of the combined signal, and the same phase component and the noise of the vector of phase, divided into a phase component shifted phase and 90 ° noise vector, the components of the size of each B _x, B _y And _B, B _x, B _y
Is represented by the following equations.

[0138] _{B x = 1 + Acosφ B y} = Asinφ B 2 = B x 2 + B y 2 = (1 + Acosφ) 2 + A 2 sin 2 φ = 1 + 2Acosφ + A 2 ... (1)

From equation (1), when φ = 180 °, B ²
Is the minimum value (1-A) ² . When A = 1, the minimum value is 0. Therefore, the optimal condition for noise reduction is φ = 180
°, A = 1. That is, the optimal conditions for noise reduction are:
The phase difference between the noise and the inverted signal is 180 °, and the peak value of the noise is equal to the peak value of the inverted signal.

Next, a condition for reducing noise, that is, a condition for satisfying B <1 is determined. The condition for B <1 is as follows from equation (1).

2Acosφ + A ² <0 (2)

From equation (2), it is necessary that A ≠ 0, that is, A> 0 (3).

When A ≠ 0, equation (2) becomes as follows. 2 cosφ + A <0 cosφ <−A / 2 (4)

Here, if A = 1, equation (4) becomes as follows. cosφ <-1/2

Therefore, when A = 1, in order to satisfy B <1, it is necessary to satisfy 120 ° <φ <240 °.

If φ = 180 °, equation (4) becomes as follows. -1 <-A / 2 A <2 (5)

Therefore, from equations (3) and (5), φ = 18
At 0 °, in order to satisfy B <1, it is necessary to satisfy 0 <A <2.

Next, as an example, a condition for satisfying B ≦ １ ／ is determined. The condition that satisfies B ≦ １ ／ is as follows from Expression (1). 1 + 2Acosφ + A ² ≦ 1/25 2Acosφ + A ² ≦ −24 / 25 (6)

Here, if A = 1, equation (6) becomes as follows. cosφ ≦ −49 / 50

Therefore, when A = 1, it is necessary to satisfy 169 ° ≦ φ ≦ 191 ° in order to satisfy B ≦ １ ／.

If φ = 180 °, equation (6) becomes as follows. −2A + A ² ≦ −24 / 25 A ² −2A + 24/25 ≦ 0 (A−4 / 5) (A−6 / 5) ≦ 0 4/5 ≦ A ≦ 6/5

Therefore, when φ = 180 °, B ≦ １ ／
In this case, it is necessary to satisfy 0.8 ≦ A ≦ 1.2.

Next, referring to FIGS. 15 and 16, power line noise filter 8 according to the present embodiment shown in FIG. 13 will be described.
An embodiment of the present invention will be described. FIG. 15 is a block diagram showing the configuration of the power line noise filter 80 of the present embodiment.
FIG. 6 is a circuit diagram showing a configuration of the power line noise filter 80 of the present embodiment.

The power line noise filter 80 of the present embodiment reduces voltage common mode noise on the power line 1 as in the second embodiment. As shown in FIG. 15, in the power line noise filter 80, the detection circuit 81 includes a capacitor 81a having one end connected to the conductive line 1a and the other end connected to the input end of the antiphase signal generation circuit 82.
And a capacitor 81b having one end connected to the conductive line 1b and the other end connected to the input end of the inverted-phase signal generation circuit 82. Capacitors 81a and 81b allow high-frequency components of voltage fluctuations in conductive lines 1a and 1b to pass, and block low-frequency components including the frequency of AC power. In the power line noise filter 80, the injection circuit 83 includes a capacitor 83 having one end connected to the output end of the negative-phase signal generation circuit 82 and the other end connected to the conductive line 1a.
a, and a capacitor 83b having one end connected to the output end of the inverted-phase signal generation circuit 82 and the other end connected to the conductive line 1b. In this example, the injection circuit 83 gives the same voltage change corresponding to the negative-phase signal to the conductive lines 1a and 1b via the capacitors 83a and 83b.

As shown in FIG. 16, in the power line noise filter 80 of the present embodiment, the anti-phase signal generation circuit 8
2 has a transformer 86. One end of the primary winding of the transformer 86 is connected to the capacitors 81a and 81b. The other end of the primary winding of the transformer 86 and one end of the secondary winding of the transformer 86 are connected to the circuit ground (signal ground). The other end of the secondary winding of the transformer 86 is connected to the impedance element 85.

In addition, the power line noise filter 80 of the present embodiment
, A common mode choke coil 87 is used for the impedance element 84, and a line choke coil 88 is used for the impedance element 85.

In the power line noise filter 80 of this embodiment, the capacitance of the capacitors 81a and 81b is set so that, for example, the leakage current value falls within a predetermined standard value. Specifically, the capacitors 81a, 81b, 83
a, 83b are, for example, 10-20,0.
Within the range of 00 pF.

It is ideal that the turns ratio between the primary winding and the secondary winding of the transformer 86 is 1: 1. However, even if the turns ratio is changed in consideration of the signal attenuation in the transformer 86, Good.

Next, the power line noise filter 80 of this embodiment is described.
An example of the characteristic will be described. In this example, the power line noise filter 80 was configured under the following conditions. That is, the capacitance of the capacitors 81a, 81b, 83a, 83b is 1000 pF. The turn ratio between the primary winding and the secondary winding of the transformer 86 is 1: 1. Also, the transformer 86
Is 0.1 μH on the primary winding side. Impedance element 84 (common mode choke coil 8
The impedance in 7) is 10 μH. The impedance of the impedance element 85 (the line choke coil 88) is 10 μH.

For comparison with the characteristics of the power line noise filter 80 of the present embodiment, the following two comparative examples were configured. The circuit of the first comparative example is a circuit including only the noise path among the noise path and the reverse phase signal path included in the circuit illustrated in FIG. The circuit of the first comparative example is, specifically, a circuit in which only the impedance element 84 (common mode choke coil 87) of the present embodiment is inserted into the power line 1 as shown in FIG. The circuit of the second comparative example is a circuit including only the path of the reverse phase signal among the path of the noise and the path of the reverse phase signal included in the circuit shown in FIG. The circuit of the second comparative example is specifically shown in FIG.
As shown in FIG. 16, the circuit shown in FIG. 16 is obtained by removing the portion of the power line 1 from the detection circuit 81 to the injection circuit 83 and the impedance element 84.

FIG. 19 shows the frequency characteristics of the absolute value of the impedance of each of the power line noise filter 80 of the present embodiment and the circuits of the first and second comparative examples. FIG.
, A line denoted by reference numeral 91 represents a characteristic of the circuit of the first comparative example and a characteristic of the circuit of the second comparative example, and a line denoted by reference numeral 92.
The line shown by represents the characteristic of the power line noise filter 80 of the present embodiment.

FIG. 20 shows the frequency characteristics of the initial phase of the impedance of each of the power line noise filter 80 of this embodiment and the circuits of the first and second comparative examples. FIG.
At 0, the line denoted by reference numeral 93 represents the characteristics of the circuit of the first comparative example and the characteristics of the circuit of the second comparative example, and
The line indicated by 4 represents the characteristic of the power line noise filter 80 of the present embodiment.

FIG. 21 shows the frequency characteristics of the respective gains of the power line noise filter 80 of the present embodiment and the circuits of the first and second comparative examples. In FIG.
The line indicated by 5 represents the characteristic of the circuit of the first comparative example, the line indicated by reference numeral 96 represents the characteristic of the circuit of the second comparative example, and the line indicated by reference numeral 97 is the power line noise of this embodiment. Filter 80
Represents the characteristics of From FIG. 21, according to the power line noise filter 80 of the present embodiment, the noise is significantly reduced as compared with the circuit of the first comparative example in which only the impedance element 84 (common mode choke coil 87) is inserted into the power line 1. We can see that we can do it.

Next, as a circuit of a third comparative example, FIG.
The circuit excluding the impedance element 85 (the line choke coil 88) from the circuit shown in FIG. The third comparative example is an example in which the phase of the opposite phase signal is not adjusted.

FIG. 22 shows the frequency characteristics of the respective gains of the power line noise filter 80 of the present embodiment, the circuit of the first comparative example, and the circuit of the third comparative example. In FIG. 22, a line indicated by reference numeral 98 represents the characteristic of the circuit of the first comparative example, a line indicated by reference numeral 99 represents the characteristic of the circuit of the third comparative example, and a line indicated by reference numeral 100 represents the circuit of the present embodiment. 7 illustrates characteristics of the power line noise filter 80 according to the embodiment. As shown in FIG. 22, in the circuit of the third comparative example in which the phase of the reverse phase signal is not adjusted, the circuit of the first comparative example in which only the impedance element 84 (common mode choke coil 87) is inserted into the power line 1 is shown. Also, the noise reduction rate is low. On the other hand, in the power line noise filter 80 of the present embodiment in which the phase of the inverted signal is adjusted, noise can be effectively reduced.

In the present embodiment, the impedance elements 84 and 85 are not limited to inductors, but may be circuits including inductors and capacitors.

Other configurations, operations, and effects of the present embodiment are the same as those of any of the first to seventh embodiments. Further, the usage example of the power line noise filter 10 described in the first embodiment can be applied to the power line noise filter 80 according to the present embodiment.

The present invention is not limited to the above embodiments, and various changes can be made. For example, the detected noise or the opposite-phase signal may be amplified as appropriate. Even in this case, since the noise voltage is not converted into a current having the opposite phase, the delay of the opposite phase signal with respect to the noise and the difference between the waveform of the opposite phase signal with respect to the noise waveform can be reduced.

[0169]

As described above, in the power line noise filter according to any one of the first to third aspects, the noise on the power line is detected by detecting the fluctuation of the current in the power line. A reverse-phase signal, which is a reverse-phase signal, is generated, and a change in current corresponding to the negative-phase signal is applied to the power line to cancel noise on the power line. Therefore,
Advantageous Effects of Invention According to the present invention, it is possible to effectively reduce noise on a power line in a wide frequency band and effectively reduce not only continuous noise but also sudden noise.

In the power line noise filter according to the present invention, noise propagating through two conductive lines in the power line at the same phase is detected, and the same change in current is given to the two conductive lines in the power line. Therefore, according to the present invention, it is possible to effectively reduce the common mode noise particularly on the power line.

In the power line noise filter according to the third aspect, noise generated in each of the two conductive lines in the power line is detected for each conductive line, and each noise corresponding to the detected noise for each conductive line is detected. A negative-phase signal is generated for each conductive line, and a change in current corresponding to the negative-phase signal for each conductive line is applied to each of the two conductive lines on the power line. Therefore, according to the present invention, there is an effect that normal mode noise and common mode noise on a power line can be effectively reduced.

Further, in the power line noise filter according to any one of claims 4 to 6, noise on the power line is detected by detecting a change in voltage on the power line, and a signal having a phase opposite to that of the detected noise is generated. Generates a negative-phase signal
A voltage change corresponding to the negative-phase signal is applied to the power line to cancel noise on the power line. Therefore, according to the present invention, it is possible to effectively reduce noise on a power line in a wide frequency band, and also to effectively reduce not only continuous noise but also sudden noise. Play.

In the power line noise filter according to the fifth aspect, noise propagating in the same phase on two conductive lines on the power line is detected, and the same voltage change is applied to the two conductive lines on the power line. Therefore, according to the present invention, it is possible to effectively reduce the common mode noise particularly on the power line.

In the power line noise filter according to the sixth aspect, noise generated in each of the two conductive lines in the power line is detected for each conductive line, and each noise corresponding to the detected noise of each conductive line is detected. A negative-phase signal is generated for each conductive line, and a change in voltage corresponding to the negative-phase signal for each conductive line is applied to each of the two conductive lines on the power line. Therefore, according to the present invention, there is an effect that normal mode noise and common mode noise on a power line can be effectively reduced.

In the power line noise filter according to any one of claims 7 to 9, the first noise on the power line is detected by detecting the fluctuation of the current in the power line, and the detected first noise is detected. 1
And a current change corresponding to the first negative-phase signal is applied to the power line to cancel the first noise on the power line. In this power line noise filter, a second noise on the power line is detected by detecting a fluctuation in the voltage on the power line, and a second negative-phase signal which is a signal having a phase opposite to the detected second noise. Is generated, and a voltage change corresponding to the second negative-phase signal is applied to the power line to cancel the second noise on the power line. Thus, according to the present invention,
It is possible to effectively reduce noise on the power line in a wide frequency band, and to effectively reduce not only continuous noise but also sudden noise.

In the power line noise filter according to the present invention, the first noise propagating through the two conductive lines in the power line with the same phase is detected, and the first inverse noise is applied to the two conductive lines in the power line. The same current change corresponding to the phase signal is given. Further, the power line noise filter detects a second noise propagating in the same phase on the two conductive lines in the power line, and applies the same voltage corresponding to the second antiphase signal to the two conductive lines in the power line. Give a change. Therefore, according to the present invention, it is possible to effectively reduce the common mode noise particularly on the power line.

In the power line noise filter according to the ninth aspect, the first noise generated on each of the two conductive lines in the power line is detected for each conductive line, and the first noise detected for each conductive line is detected. Generates a first negative-phase signal for each conductive line corresponding to the noise of the power line, and detects a change in current corresponding to the first negative-phase signal for each conductive line for each of the two conductive lines on the power line. give. Further, in this power line noise filter, the second noise generated in each of the two conductive lines in the power line is detected for each conductive line, and each conductive line corresponding to the detected second noise for each conductive line is detected. A second negative-phase signal is generated for each line, and a voltage change corresponding to the second negative-phase signal for each conductive line is applied to each of the two conductive lines on the power line. Therefore, according to the present invention, there is an effect that normal mode noise and common mode noise on a power line can be effectively reduced.

In the power line noise filter according to any one of the tenth to thirteenth aspects, noise on the power line is detected by detecting a current fluctuation or a voltage fluctuation in the power line by the noise detecting means. A reversed-phase signal which is a signal having a phase opposite to that of the generated noise is generated by a reverse-phase signal generating means, and a current or voltage change corresponding to the negative-phase signal is given to the power line by the noise canceling means, so that Cancel the noise. Further, in this power line noise filter, the peak value of the noise on the power line on the noise canceling means is reduced by the peak value reducing impedance element, and the peak value of the noise on the power line on the noise detecting means side and the noise canceling means are reduced. The state in which the peak value of the noise on the power line on the side is different from that of the power line is maintained. Therefore, according to the present invention, it is possible to effectively reduce the noise on the power line on the noise canceling means side.

Further, the power line noise filter according to the twelfth or thirteenth aspect is arranged such that the phase difference between the noise input to the noise canceling means and the change in the current or voltage applied to the power line by the noise canceling means approaches 180 °. And a phase adjustment impedance element having an impedance for adjusting the phase of the antiphase signal. Therefore, according to the present invention, it is possible to more effectively reduce the noise on the power line on the noise canceling means side.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a power line noise filter according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram illustrating an example of a configuration of an anti-phase signal generation circuit in FIG. 1;

FIG. 3 is an explanatory diagram showing an example of using the power line noise filter according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing another example of using the power line noise filter according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram showing still another application example of the power line noise filter according to the first embodiment of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a power line noise filter according to a second embodiment of the present invention.

FIG. 7 is a block diagram illustrating a configuration of a power line noise filter according to a third embodiment of the present invention.

FIG. 8 is a block diagram showing a configuration of a power line noise filter according to a fourth embodiment of the present invention.

FIG. 9 is a block diagram illustrating a configuration of a power line noise filter according to a fifth embodiment of the present invention.

FIG. 10 is a block diagram illustrating a configuration of a power line noise filter according to a sixth embodiment of the present invention.

FIG. 11 is a block diagram illustrating a configuration of a power line noise filter according to a seventh embodiment of the present invention.

FIG. 12 is a block diagram showing a basic configuration of a power line noise filter according to an eighth embodiment of the present invention.

FIG. 13 is a block diagram illustrating an example of a configuration of a power line noise filter according to an eighth embodiment of the present invention.

FIG. 14 is a vector diagram showing, as vectors, noises, anti-phase signals, and a synthesized signal obtained by synthesizing them in the eighth embodiment of the present invention.

FIG. 15 is a block diagram showing a configuration of a power line noise filter of an example according to the eighth embodiment of the present invention.

FIG. 16 is a circuit diagram showing a configuration of a power line noise filter of one example according to the eighth embodiment of the present invention.

FIG. 17 is a circuit diagram showing a circuit of a first comparative example with respect to one example in the eighth embodiment of the present invention.

FIG. 18 is a circuit diagram showing a circuit of a second comparative example with respect to one example in the eighth embodiment of the present invention.

FIG. 19 is a characteristic diagram illustrating frequency characteristics of absolute values of impedances of the power line noise filter of one example and the circuits of the first and second comparative examples according to the eighth embodiment of the present invention.

FIG. 20 is a characteristic diagram showing frequency characteristics of the initial phase of the impedance of each of the power line noise filter of the example and the circuits of the first and second comparative examples in the eighth embodiment of the present invention.

FIG. 21 is a characteristic diagram showing frequency characteristics of respective gains of the power line noise filter according to the eighth embodiment of the present invention and the circuits of the first and second comparative examples.

FIG. 22 is a characteristic diagram showing frequency characteristics of respective gains of the power line noise filter of the eighth embodiment of the present invention and the circuits of the first and third comparative examples.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power line, 1a, 1b ... Conduction line, 10 ... Power line noise filter, 11 ... Detection circuit, 12 ... Negative phase signal generation circuit, 1
3. Injection circuit.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G064 CA01 CB10 DA03 5G066 EA03 5K046 AA03 BA05 CC17 PP01 PP07 PS11 PS52 PS53 PS54

Claims (13)

[Claims] 1. A noise detecting means for detecting noise on a power line by detecting a fluctuation of a current in a power line, and generating a reverse-phase signal which is a signal having a reverse phase to the noise detected by the noise detecting means. By applying a change in current corresponding to the negative-phase signal generated by the negative-phase signal generating means to the power line,
And a noise canceling means for canceling noise on the power line. 2. The noise detection means according to claim 1, wherein
The noise which propagates in the same phase through two conductive lines is detected, and the noise canceling means gives the same current change to two conductive lines in the power line.
A power line noise filter as described in the above. 3. The noise detection means according to claim 2, wherein
The noise generated in each of the conductive lines is detected for each of the conductive lines, and the negative-phase signal generating means includes an inverse signal for each conductive line corresponding to the noise for each of the conductive lines detected by the noise detecting means. Generating a phase signal, wherein the noise canceling means detects, for each of the two conductive lines in the power line, a change in current corresponding to the negative-phase signal for each conductive line generated by the negative-phase signal generating means. The power line noise filter according to claim 1, wherein 4. A noise detecting means for detecting noise on the power line by detecting a voltage fluctuation on the power line, and generating a reverse-phase signal which is a signal having a phase opposite to the noise detected by the noise detecting means. By applying a voltage change corresponding to the negative-phase signal generated by the negative-phase signal generating means to the power line,
And a noise canceling means for canceling noise on the power line. 5. The noise detection means according to claim 2, wherein
5. The method according to claim 4, further comprising the step of detecting noise propagating in the same phase through the two conductive lines, wherein the noise canceling means applies the same voltage change to the two conductive lines in the power line.
A power line noise filter as described in the above. 6. The noise detection means according to claim 2, wherein
The noise generated in each of the conductive lines is detected for each of the conductive lines, and the negative-phase signal generating means includes an inverse signal for each conductive line corresponding to the noise for each of the conductive lines detected by the noise detecting means. Generating a phase signal, wherein the noise canceling means generates a change in voltage corresponding to the negative phase signal of each conductive line generated by the negative phase signal generating means for each of the two conductive lines in the power line. The power line noise filter according to claim 4, wherein the power line noise filter is provided. 7. A first noise detecting means for detecting a first noise on a power line by detecting a change in a current in the power line, and a first noise detected by the first noise detecting means. A first negative-phase signal generating means for generating a first negative-phase signal serving as a negative-phase signal; and a first negative-phase signal generated by the first negative-phase signal generating means for the power line. A first noise canceling means for canceling the first noise on the power line by giving a change in the current, and a second means for detecting the second noise on the power line by detecting a voltage change in the power line. A second negative-phase signal generating means for generating a second negative-phase signal which is a signal having a negative phase with respect to the second noise detected by the second noise detecting means; Generated by the second negative-phase signal generating means. By providing a voltage change corresponding to the second phase-inverted signal, power line noise filter characterized by comprising a second noise cancellation means for canceling the second noise on the power line. 8. The first noise detecting means detects first noise propagating in the same phase on two conductive lines in the power line, and the first noise canceling means detects the two conductive lines in the power line. Giving the same change in current to the line, the second noise detecting means detects a second noise propagating in the same phase through two conductive lines in the power line, the second noise canceling means, The power line noise filter according to claim 7, wherein the same voltage change is applied to two conductive lines in the power line. 9. The first noise detecting means detects, for each conductive line, first noise generated on each of two conductive lines in a power line, and wherein the first negative-phase signal generating means comprises: The first noise canceling means generates a first negative-phase signal for each conductive line corresponding to the first noise for each conductive line detected by the first noise detecting means, Applying a change in current corresponding to the first negative-phase signal for each conductive line generated by the first negative-phase signal generating means to each of the conductive lines; Detects, for each conductive line, a second noise generated in each of the two conductive lines in the power line, and wherein the second negative-phase signal generating unit detects each of the second noises detected by the second noise detecting unit. Generating a second negative-phase signal for each conductive line corresponding to the second noise for each conductive line; The killing means applies, to each of the two conductive lines in the power line, a voltage change corresponding to a second negative-phase signal for each conductive line generated by the second negative-phase signal generating means. The power line noise filter according to claim 7, wherein: 10. A noise detecting means which is arranged at a predetermined position on a power line and detects a fluctuation of a current or a voltage of the power line to detect noise on the power line, and a noise detected by the noise detecting means. Anti-phase signal generating means for generating an anti-phase signal that is an anti-phase signal, and a power line is arranged at a position different from the detection means, and noise is detected by detecting a change in current in the noise detection means. In the case where the noise is detected by giving a change in current corresponding to the negative-phase signal generated by the negative-phase signal generating means to the power line and detecting a voltage change by the noise detecting means, To cancel the noise on the power line by applying a voltage change corresponding to the negative-phase signal generated by the negative-phase signal generation means to the power line. Noise canceling means, and a peak value reduction provided at a position on the power line between the position where the noise detecting means is arranged and the position where the noise canceling means is arranged, and having an impedance for reducing the peak value of the passing noise. A power line noise filter comprising: 11. The power line noise filter according to claim 10, wherein said peak value reducing impedance element includes an inductor. 12. A signal path from the noise detecting means to the noise canceling means via the anti-phase signal generating means and provided to the power line by the noise input to the noise canceling means and the noise canceling means. The power line according to claim 10, further comprising a phase adjustment impedance element having an impedance for adjusting a phase of the opposite-phase signal so that a phase difference with a change in current or voltage approaches 180 °. Noise filter. 13. The power line noise filter according to claim 12, wherein said impedance element for phase adjustment includes an inductor.