WO2003100972A1

WO2003100972A1 - Complex resonance circuit and filter

Info

Publication number: WO2003100972A1
Application number: PCT/JP2003/006510
Authority: WO
Inventors: Masaru Wasaki; Yoshihiro Saitoh
Original assignee: Tdk Corporation
Priority date: 2002-05-27
Filing date: 2003-05-26
Publication date: 2003-12-04
Also published as: TW200404405A; JP4233273B2; JP2003347879A

Abstract

A complex resonance circuit comprises one inductance element (1) and two capacitors (2, 3) connected to the inductance element (1). The inductance element (1) has one magnetic core (10), a winding (11) wound around the magnetic core (10), and two resonance windings (12, 13). Terminals (11a, 11b) are connected to both ends of the winding (11), respectively. Both ends of the resonance winding (12) are connected via a capacitor (2), and both ends of the resonance winding (13) via a capacitor (3). The magnetic core (10), the resonance winding (12), and the capacitor (2) constitute a first parallel resonance circuit. The magnetic core (10), the resonance winding (13), and the capacitor (3) constitute a second parallel resonance circuit. The complex resonance circuit has a complex resonance characteristic determined by combining of the resonance characteristics of the two parallel resonance circuits.

Description

Composite resonance circuits and filters

The present invention relates to a composite resonance circuit that can be used as a filter for reducing ripple voltage and noise, and a filter including the composite resonance circuit.

Light

Background art

Power electronics devices, such as switching power supplies, inverters, and lighting circuits for lighting devices, have power conversion circuits that convert power. This power conversion circuit usually performs power conversion using an alternating current having a frequency of 20 kHz or higher. The power conversion circuit has a switching circuit that converts a direct current into a rectangular wave alternating current. The power conversion circuit generates a ripple voltage having a frequency equal to the switching frequency of the switching circuit and noise associated with the switching operation of the switching circuit. The ripple voltage and noise adversely affect other devices. Therefore, it is necessary to provide a means to reduce ripple voltage and noise between the power conversion circuit and other devices or lines.

Generally, as a means for reducing the ripple voltage and noise, a filter including an inductance element (inductor) and a capacitor, a so-called LC filter, is used.

However, a DC or AC current for power transport flows through the filter for the power conversion circuit. Therefore, a filter for a power conversion circuit is required to obtain desired characteristics while a current for power transfer is flowing, and to take measures against a rise in temperature. Therefore, usually, a ferrite core with a gap is used as a magnetic core in an inductance element in a filter for a power conversion circuit. However, such an inductance element has a problem in that its characteristics approach those of an air-core inductance element, so that the inductance element becomes large in order to achieve desired characteristics. Disclosure of the invention

An object of the present invention is to provide a composite resonance circuit that can be used as a filter for reducing a ripple voltage and noise generated by a power conversion circuit and that can be miniaturized, and a filter including the composite resonance circuit. .

The composite resonance circuit according to the present invention has a resonance characteristic different from each other, includes a plurality of composite parallel resonance circuits, and has a composite resonance characteristic obtained by combining the resonance characteristics of the respective parallel resonance circuits.

In the composite resonance circuit of the present invention, the resonance characteristics of the plurality of parallel resonance circuits are combined to obtain the composite resonance characteristics.

In the composite resonance circuit of the present invention, the plurality of parallel resonance circuits may include one inductance element including a plurality of inductance elements, and one or more capacitors connected to the inductance element.

The inductance element has one magnetic core and a plurality of windings wound on the magnetic core, and these form a plurality of inductance elements, each of which is connected to a separate capacitor. Is also good.

The inductance element has a plurality of bonded magnetic cores and a plurality of windings wound around each of the magnetic cores, and these form a plurality of inductance elements, each of which has a separate capacitor. Evening may be connected. In this case, the plurality of cores may have different characteristics from each other.

Further, the inductance element has a plurality of magnetic cores having different characteristics from each other, and one winding wound around the plurality of magnetic cores, and these constitute a plurality of inductance elements. One capacity may be connected.

In the composite resonance circuit according to the present invention, the plurality of parallel resonance circuits may include a plurality of windings and a capacitor connected to each winding in parallel. A plurality of windings may be connected in series. In this case, the plurality of parallel resonance circuits may further have one magnetic core on which a plurality of windings are wound. Alternatively, the plurality of parallel resonance circuits may further include a plurality of magnetic cores each wound with a respective winding. Further, in the composite resonance circuit of the present invention, the frequency range in which the absolute value of the impedance of each of the plurality of parallel resonance circuits is equal to or more than a predetermined value partially overlaps, The frequency range in which the absolute value of the impedance becomes equal to or more than a predetermined value may be wider than the above-mentioned frequency range of each parallel resonance circuit.

In the composite resonance circuit of the present invention, the frequency ranges in which the absolute value of the impedance of each of the plurality of parallel resonance circuits is equal to or more than a predetermined value are separated from each other, and the absolute value of the impedance of the composite resonance circuit is equal to or more than a predetermined value The frequency range may include the above-mentioned frequency range of each parallel resonance circuit.

In the composite resonance circuit according to the present invention, the absolute value of the impedance of the composite resonance circuit in a predetermined frequency range may be larger than that of each of the plurality of parallel resonance circuits in the frequency range.

The filter of the present invention reduces a signal in a predetermined frequency range. The filter of the present invention has different resonance characteristics from each other, includes a plurality of combined parallel resonance circuits, and has a composite resonance characteristic obtained by combining the resonance characteristics of the respective parallel resonance circuits. The filter of the present invention reduces a signal in a predetermined frequency range by using the composite resonance characteristic.

Other objects, features and benefits of the present invention will become more fully apparent from the following description. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory diagram showing a configuration of a composite resonance circuit according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing an equivalent circuit of the composite resonance circuit shown in FIG. FIG. 3 is a circuit diagram showing a parallel resonance circuit.

FIG. 4 is an explanatory diagram conceptually showing the frequency characteristic of the absolute value of the impedance of the parallel resonance circuit shown in FIG.

FIG. 5 is a characteristic diagram for describing a first example of a composite resonance characteristic of the composite resonance circuit according to the first embodiment of the present invention.

FIG. 6 is a characteristic diagram for explaining a second example of the composite resonance characteristics of the composite resonance circuit according to the first embodiment of the present invention.

FIG. 7 is a plan view showing a first example of a magnetic core according to the first embodiment of the present invention. is there.

FIG. 8 is a plan view showing a second example of the magnetic core according to the first embodiment of the present invention.

FIG. 9 is a plan view showing a third example of the magnetic core according to the first embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a configuration of a composite resonance circuit according to a second embodiment of the present invention.

FIG. 11 is a circuit diagram showing an equivalent circuit of the composite resonance circuit shown in FIG. FIG. 12 is an explanatory diagram showing a configuration of a composite resonance circuit according to a third embodiment of the present invention.

FIG. 13 is a circuit diagram showing an equivalent circuit of the composite resonance circuit shown in FIG. FIG. 14 is an explanatory diagram showing the configuration of the composite resonance circuit according to the fourth embodiment of the present invention.

FIG. 15 is a circuit diagram showing an equivalent circuit of the composite resonance circuit shown in FIG. FIG. 16 is a characteristic diagram showing composite resonance characteristics of the composite resonance circuit according to the fourth embodiment of the present invention.

FIG. 17 is an explanatory diagram showing the configuration of the composite resonance circuit according to the fifth embodiment of the present invention.

FIG. 18 is a block diagram showing a schematic configuration of a noise suppression circuit including a filter according to a sixth embodiment of the present invention.

FIG. 19 is a block diagram showing a configuration of the low-frequency noise reduction circuit in FIG.

FIG. 20 is a circuit diagram showing an example of the configuration of the high-frequency noise reduction circuit in FIG. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]

First, with reference to FIG. 1 and FIG. 2, a complex according to the first embodiment of the present invention will be described. The configuration of the combined resonance circuit will be described. FIG. 1 is an explanatory diagram showing the configuration of the composite resonance circuit according to the present embodiment, and FIG. 2 is a circuit diagram showing an equivalent circuit of the composite resonance circuit shown in FIG.

As shown in FIG. 1, the composite resonance circuit according to the present embodiment includes one inductance element 1 and two capacitors 2 and 3 connected to the inductance element 1.

The inductance element 1 has one magnetic core 10. The magnetic core 10 is composed of a central leg 10a and two legs 10b, 1 arranged on both sides of the leg 10a at a predetermined distance from the leg 10a. The connecting part 10d that connects each end of the legs 10 &, 10b, 10c and the other end of the legs 10a, 10b, 10c And a connecting portion 10e to be connected. The inductance element 1 further includes a winding 11 wound around the leg 10a, a resonance winding 12 wound around the leg 10b, and a resonance winding wound around the leg 10c. And winding 13. Terminals 11 a and 11 b are connected to both ends of the winding 11, respectively. Both ends of the resonance winding 12 are connected via a capacitor 2, and both ends of the resonance winding 13 are connected via a capacitor 3. As shown in FIG. 2, the magnetic core 10, the resonance winding 12 and the capacitor 2 constitute a first parallel resonance circuit 21, and the magnetic core 10, the resonance winding 13 and the capacitor 3 Constitutes the second parallel resonance circuit 22. The magnetic core 10 and the resonance winding 12 form one inductance element, and the magnetic core 10 and the resonance winding 13 form another inductance element. The winding 11 and the resonance winding 12 are magnetically coupled via the magnetic core 10. Similarly, the winding 11 and the resonance winding 13 are magnetically coupled via the magnetic core 10.

The first parallel resonance circuit 21 and the second parallel resonance circuit 22 have different resonance characteristics. In particular, the resonance frequency of the first parallel resonance circuit 21 and the resonance frequency of the second parallel resonance circuit 22 are different from each other. In order to make the resonance characteristics of the first parallel resonance circuit 21 and the second parallel resonance circuit 22 different, the inductances of the resonance windings 12 and 13 are made different, or the capacitance of the capacitors 2 and 3 is changed. You can make them different, or both.

Here, a general parallel resonance circuit will be described with reference to FIGS. 3 and 4. I do. FIG. 3 is a circuit diagram showing a parallel resonance circuit. The parallel resonance circuit includes two terminals 31 and 32, and a coil 33 and a capacitor 34 connected in parallel with each other between the two terminals 31 and 32. The coil 33 has a magnetic core 33a and a winding 33b wound around the magnetic core 33a. In FIG. 3, reference numeral 35 denotes a virtual resistor having a resistance value equal to the internal resistance of the coil 33 due to magnetic loss or the like in the magnetic core 33a. As shown in FIG. 3, the virtual resistor 35 can be considered to be connected in series with the coil 33.

Next, the resonance characteristics of the parallel resonance circuit shown in FIG. 3 will be described. Here, let the inductance of the coil 33 in FIG. 3 be L, the capacity of the capacitor 34 be C, and the resistance of the resistor 35 be R s. The resonance frequency f of the parallel resonance circuit shown in FIG. Is represented by the following equation.

f 0 = 1 / {2 i f (L · C)}

FIG. 4 conceptually shows the frequency characteristic of the absolute value of the impedance for each of the parallel resonance circuit and the coil 33 shown in FIG. In FIG. 4, reference numeral 38 indicates the characteristic of the parallel resonance circuit, and reference numeral 39 indicates the characteristic of the coil 33 alone. As shown in FIG. 4, the absolute value of the impedance of the parallel resonance circuit is the resonance frequency f. At the peak value. The peak value is equal to the resistance value R s. On the other hand, the absolute value of the impedance of the coil 33 alone is represented by 2πfL, where f is the frequency. At the resonance frequency f _Q , the absolute value of the impedance of the parallel resonance circuit is much larger than the absolute value of the impedance of the coil 33 alone. Therefore, the parallel resonance circuit is inserted in the middle of the conductive wire, and the resonance frequency f of the parallel resonance circuit is set. It can be seen that setting the frequency near the frequency of the ripple voltage or noise to be reduced can effectively reduce the ripple voltage or noise.

The resonance windings 12 and 13 in the present embodiment correspond to the winding 33b in FIG. Capacitors 2 and 3 in the present embodiment correspond to capacitor 34 in FIG.

In the composite resonance circuit according to the present embodiment, one magnetic core 10 combines two parallel resonance circuits 21 and 22. The winding 11 is connected to the resonance winding 12 of the parallel resonance circuit 21 and the resonance winding 13 of the parallel resonance circuit 22 via the magnetic core 10. And are magnetically coupled. Therefore, the winding 11 has composite resonance characteristics in which the resonance characteristics of the two parallel resonance circuits 21 and 22 are composited.

The composite resonance circuit according to the present embodiment is inserted in the middle of a conductive wire by connecting winding 11 to the conductive wire via terminals 11a and 11b. For example, a composite resonance circuit can be inserted in the middle of a conductive line on the input side or output side of a power conversion circuit in a switching power supply or the like. Composite resonance circuits reduce ripple voltage and noise propagating on conductive lines. Therefore, the composite resonance circuit according to the present embodiment can be used as a filter for reducing a ripple voltage or noise propagating on a conductive line.

Further, if the composite resonance circuit according to the present embodiment is inserted into one of the pair of conductive wires, normal mode noise propagating on the conductive wire can be reduced. In addition, if a composite resonance circuit is inserted into each of the pair of conductive wires, common mode noise propagating on the conductive wires can be reduced.

Next, first and second examples of composite resonance characteristics of the composite resonance circuit according to the present embodiment will be described with reference to FIG. 5 and FIG. The first example is an example in which the resonance frequencies of the parallel resonance circuits 21 and 22 are relatively close to each other. FIG. 5 shows the frequency characteristics of the absolute value of the impedance of each of the parallel resonance circuits 21 and 22 as the resonance characteristics of the parallel resonance circuits 21 and 22 in the first example. In FIG. 5, reference numeral 41 denotes a characteristic of the parallel resonance circuit 21, and reference numeral 42 denotes a characteristic of the parallel resonance circuit 22. Represents the resonance frequency of the parallel resonance circuit 21, and f ₂ represents the resonance frequency of the parallel resonance circuit 22. The absolute value of the impedance of the composite resonance circuit for each frequency matches the larger of the absolute values of the impedances of the parallel resonance circuits 21 and 22 for each frequency. '

In the first example, the frequency range in which the absolute value of the impedance of each of the parallel resonance circuits 21 and 22 is equal to or more than a predetermined value (for example, one half of the maximum value of the absolute value of the impedance in the composite resonance circuit) is Partially overlapping. The frequency range in which the absolute value of the impedance of the composite resonance circuit is equal to or greater than the predetermined value is wider than the frequency range of each of the parallel resonance circuits 21 and 22. Therefore, according to the composite resonance circuit of the first example, the ripple voltage and noise are reduced as compared with the case of using one parallel resonance circuit. The frequency range that can be reduced can be expanded.

The second example is an example in which the resonance frequencies of the parallel resonance circuits 21 and 22 are respectively set to desired frequencies. FIG. 6 shows the frequency characteristics of the absolute value of the impedance of each of the parallel resonance circuits 21 and 22 as the resonance characteristics of the parallel resonance circuits 21 and 22 in the second example. In FIG. 6, reference numeral 41 indicates the characteristics of the parallel resonance circuit 21, and reference numeral 42 indicates the characteristics of the parallel resonance circuit 22. Represents the resonance frequency of the parallel resonance circuit 21, and f ₂ represents the resonance frequency of the parallel resonance circuit 22. The absolute value of the impedance of the composite resonance circuit for each frequency matches the larger of the absolute values of the impedances of the parallel resonance circuits 21 and 22 for each frequency. In the second example, the frequency range in which the absolute value of the impedance of each of the parallel resonant circuits 21 and 22 is equal to or more than a predetermined value (for example, half the maximum value of the absolute value of the impedance in the composite resonant circuit) is Separated from each other. The frequency range in which the absolute value of the impedance of the composite resonance circuit is equal to or more than the above-described predetermined value includes the above-described frequency range of each of the parallel resonance circuits 21 and 22. Therefore, according to the composite resonance circuit of the second example, it is possible to reduce ripple voltage and noise in two frequency ranges. FIG. 6 also shows a waveform of a ripple voltage having a frequency equal to the switching frequency of the switching circuit, and a waveform of a noise accompanying the switching operation of the switching circuit. In FIG. 6, reference numeral 43 indicates a ripple voltage waveform, and reference numeral 44 indicates a noise waveform. Usually, the frequency of the ripple voltage is less than 500 kHz and the frequency of the noise is more than 1 MHz. In a second example, according to the frequency of the parallel resonance circuit 2 first resonant frequency 1 ^ ripple voltage, the resonance frequency f ₂ of the parallel resonance circuit 2 2, combined with the frequency of the noise, the ripple voltage and noise effectively It can be reduced. Therefore, according to the second example, comprehensive measures can be taken against ripple voltage and noise generated by the power conversion circuit.

Next, three examples of the magnetic core 10 in the present embodiment will be described with reference to FIGS. 7 to 9. FIG. As shown in FIG. 7, the magnetic core 10 of the first example is entirely formed of the same magnetic material. The magnetic core 10 may be made of, for example, a ferrite amorphous magnetic material, or may be a dust core. Note that the shape of the magnetic core 10 shown in FIG. 7 is an example, and a magnetic circuit equivalent to the magnetic core 10 shown in FIG. What constitutes the path is included in the magnetic core 10 of the first example. Further, the magnetic core 10 of the first example may be configured by joining a plurality of members. Specifically, as the magnetic core 10 of the first example, for example, an EE-type magnetic core / EI-type magnetic core / pot-type magnetic core can be used.

As shown in FIG. 8, the magnetic core 10 of the second example is formed by joining two magnetic cores 1 OA and 10 B that can form an annular magnetic circuit by themselves. The magnetic cores 10A and 10B may be different in shape and size from each other. When the magnetic core 10 of the second example is used, the inductance element 1 shown in FIG. 1 is composed of two magnetic cores 10 A, 108 joined together, It has two windings 12 and 13 wound around 0 B, and these constitute two inductance elements.

As shown in FIG. 9, the magnetic core 10 of the third example is configured by joining two magnetic cores 10 C and 10 D that can form an annular magnetic circuit by themselves. . The magnetic cores 10 C and 10 D have different characteristics from each other. Specifically, for example, the magnetic cores 10 C and 10 D are formed of magnetic materials having different magnetic permeability from each other. As the material of the magnetic cores 10C and 10D, any material having different characteristics from ferrite, an amorphous magnetic material, a material for a dust core, and the like can be used. When the magnetic core 10 of the third example is used, the inductance element 1 shown in FIG. 1 has two magnetic cores 100 C, 100 having different characteristics from each other, and each magnetic core 10 has the same characteristics. , 10D, and two windings 12, 23, which constitute two inductance elements. When the magnetic core 10 of the third example is used, even if the windings wound on the magnetic cores 10 C and 10 D are the same, the frequency characteristic of the impedance of each winding is Will be different.

As described above, the composite resonance circuit according to the present embodiment has composite resonance characteristics obtained by combining the resonance characteristics of a plurality of parallel resonance circuits. Then, in the present embodiment, the ripple voltage and noise generated by the power conversion circuit can be reduced by using the composite resonance characteristic. Further, in the present embodiment, since the composite resonance characteristic is used, it is possible to reduce noise having a certain range of frequency, and simultaneously reduce ripple voltage and noise having different frequencies. Thus, composite Resonant circuits can be used as filters to reduce ripple voltage and noise generated by power conversion circuits. Also, in the composite resonance circuit, the ripple voltage and noise are reduced by using the composite resonance characteristics, so that the inductance element can be reduced in size compared to the LC filter. As a result, the entire composite resonance circuit is also reduced in size compared to the LC filter. It can be changed.

Further, according to the present embodiment, a plurality of parallel resonant circuits 21, 1, 2, 1, 2, 3, and 2 is connected using one inductance element 1 including a plurality of inductance elements and capacitors 2, 3 connected to the inductance element 1. 22 can be configured. Therefore, according to the present embodiment, it is possible to further reduce the size of the composite resonance circuit as compared with a case where a plurality of parallel resonance circuits are formed using a plurality of inductance elements.

[Second embodiment]

Next, a composite resonance circuit according to a second embodiment of the present invention will be described with reference to FIG. 10 and FIG. FIG. 10 is an explanatory diagram showing the configuration of the composite resonance circuit according to the present embodiment, and FIG. 11 is a circuit diagram showing an equivalent circuit of the composite resonance circuit shown in FIG.

As shown in FIG. 10, the composite resonance circuit according to the present embodiment includes one inductance element 51 and one capacitor 52 connected to the inductance element 51. I have.

The inductance element 51 has two magnetic cores 53A and 53B, each of which forms an annular magnetic circuit. The two magnetic cores 53A and 53B each have a hollow portion, are arranged so that the axial directions of the two hollow portions match, and are joined to each other. The magnetic cores 53A and 53B have different characteristics from each other. Specifically, for example, the magnetic cores 53A and 53B are formed of magnetic materials having different magnetic permeability from each other. As the material of the magnetic cores 53A and 53B, any material having different characteristics can be used from ferrite, an amorphous magnetic material, a material for a dust core, and the like.

The inductance element 51 further includes a winding 54 wound around the magnetic cores 53A and 53B and a resonance winding 55 wound around the magnetic cores 53A and 53B. Have. Terminals 54a and 54b are connected to both ends of the winding 54, respectively. Both ends of the resonance winding 55 are connected via a capacitor 52. Since the resonance winding 55 is wound around the magnetic cores 53 A and 53 B having different characteristics from each other, the winding wound around the magnetic core 53 A as shown in FIG. It can be regarded as including a portion 55a and a winding portion 55b wound around the magnetic core 53B. In this case, the winding portions 55a and 55b can be considered to be connected in parallel. The capacitor 52 can be considered to be provided between both ends of the winding part 55a and between both ends of the winding part 55b. The magnetic core 53 A, the winding part 55 a and the capacitor 52 constitute the first parallel resonance circuit, and the magnetic core 53 B, the winding part 55 b and the capacity 52 constitute the second parallel resonance circuit. Make up the circuit. Also, one inductance element is constituted by the magnetic core 53A and the winding part 55a, and another inductance element is constituted by the magnetic core 53B and the winding part 55b. . The winding 54 and the winding 55a are magnetically coupled via a magnetic core 53A, and the winding 54 and the winding 55b are magnetically coupled via a magnetic core 53B. Is joined to.

Further, since the characteristics of the magnetic cores 53A and 53B are different from each other, the inductances of the winding portions 55a and 55b are different from each other. Therefore, the first parallel resonance circuit and the second parallel resonance circuit have different resonance characteristics from each other. In particular, the resonance frequency of the first parallel resonance circuit and the resonance frequency of the second parallel resonance circuit are different from each other.

In the composite resonance circuit according to the present embodiment, two parallel resonance circuits are composited by one resonance winding 55 and one capacitor 52. The winding 54 is magnetically coupled to the resonance winding 55 via the magnetic cores 53 A and 53 B. Therefore, the winding 54 has composite resonance characteristics in which the resonance characteristics of the two parallel resonance circuits are composited.

The composite resonance circuit according to the present embodiment is inserted in the middle of the conductive wire by connecting winding 54 to the conductive wire via terminals 54a and 54b. The composite resonance circuit can be used as a filter for reducing ripple voltage and noise propagating on the conductive line.

Other configurations, operations, and effects of the present embodiment are the same as those of the first embodiment.

[Third Embodiment] Next, a composite resonance circuit according to a third embodiment of the present invention will be described with reference to FIG. 12 and FIG. FIG. 12 is an explanatory diagram showing the configuration of the composite resonance circuit according to the present embodiment, and FIG. 13 is a circuit diagram showing an equivalent circuit of the composite resonance circuit shown in FIG.

As shown in FIG. 12, the composite resonance circuit according to the present embodiment includes one inductance element 61 and one capacitor 62 connected to the inductance element 61. I have.

The inductance element 61 has two magnetic cores 63A and 63B, each of which forms an annular magnetic circuit. The magnetic cores 63A and 63B are joined to each other. The arrangement and materials of the magnetic cores 63A and 63B are the same as those of the magnetic cores 53A and 53B in the second embodiment.

The inductance element 61 further has a winding 65 wound around the magnetic cores 63A and 63B. Terminals 65c and 65d are connected to both ends of the winding 65, respectively. Further, both ends of the winding 65 are connected via a capacitor 62.

Since the winding 65 is wound around the magnetic cores 6 3 A and 6 3 B having different characteristics from each other, as shown in FIG. 13, the winding portion 6 5 wound around the magnetic core 6 3 A is used. a and a winding portion 65b wound around the magnetic core 63B. In this case, the winding portions 65a and 65b can be considered to be connected in parallel. The capacitor 62 can be considered to be provided between both ends of the winding portion 65a and between both ends of the winding portion 65b. The magnetic core 63 A, the winding part 65 a and the capacitor 62 constitute the first parallel resonance circuit, and the magnetic core 63 B, the winding part 65 b and the capacitor 62 constitute the second parallel resonance circuit. Make up the circuit. The magnetic core 63A and the winding part 65a constitute one inductance element, and the magnetic core 63B and the winding part 65 constitute another inductance element.

Also, since the characteristics of the magnetic cores 63A and 63B are different from each other, the inductances of the winding portions 65a and 65b are different from each other. Therefore, the first parallel resonance circuit and the second parallel resonance circuit have different resonance characteristics from each other. In particular, the resonance frequency of the first parallel resonance circuit and the resonance frequency of the second parallel resonance circuit are different from each other. In the composite resonance circuit according to the present embodiment, one winding 65 and one capacitor 62 combine two parallel resonance circuits. Therefore, this composite resonance circuit has composite resonance characteristics in which the resonance characteristics of two parallel resonance circuits are composited. The composite resonance circuit according to the present embodiment is inserted in the middle of the conductive wire by connecting winding 65 to the conductive wire via terminals 65c and 65d. The composite resonance circuit can be used as a filter for reducing ripple voltage and noise propagating on the conductive line.

Other configurations, operations, and effects of the present embodiment are the same as those of the second embodiment.

[Fourth embodiment]

Next, a composite resonance circuit according to a fourth embodiment of the present invention will be described with reference to FIGS. 14 to 16. FIG. 14 is an explanatory diagram showing the configuration of the composite resonance circuit according to the present embodiment, FIG. 15 is a circuit diagram showing an equivalent circuit of the composite resonance circuit shown in FIG. 14, and FIG. FIG. 4 is a characteristic diagram illustrating composite resonance characteristics of the composite resonance circuit according to the embodiment.

As shown in FIG. 14, the composite resonance circuit according to the present embodiment includes one inductance element 71, and two capacitors 72, 73 connected to the inductance element 71. It has. The inductance element 71 has one magnetic core 74. The magnetic core 74 is composed of a central leg 74a and two legs 74b, 7b arranged on both sides of the leg 74a at a predetermined distance from the leg 74a. 4c, a connecting portion 74d for connecting one end of each of the legs 74a, 74b, 74c and the other end of each of the legs 74a, 74b, 74c. And a connecting portion 74 e to be connected. The magnetic core 74 may be entirely made of the same magnetic material, similarly to the magnetic core 10 shown in FIG. Alternatively, like the magnetic core 10 shown in FIG. 8, the magnetic core 74 may be configured by joining two magnetic cores each of which can form an annular magnetic circuit by itself. Alternatively, similarly to the magnetic core 10 shown in FIG. 9, the magnetic core 74 is configured by joining two magnetic cores that have different characteristics from each other and that can form an annular magnetic circuit by themselves. It may be. The inductance element 71 further includes a winding 75 wound around the leg 74b and a winding 76 wound around the leg 74c. Both ends of the winding 75 are connected via a capacitor 72, and both ends of the winding 76 are connected via a capacitor 73. A terminal 77 is connected to one end of the winding 75. The other end of the winding 75 is connected to one end of the winding 76. A terminal 78 is connected to the other end of the winding 76. Therefore, as shown in FIG. 15, the winding 75 and the winding 76 are connected in series.

As shown in FIG. 15, the magnetic core 74, the winding 75 and the capacitor 72 constitute a first parallel resonance circuit 79, and the magnetic core 74, the winding 76 and the capacitor 73 Constitutes the second parallel resonance circuit 80. The core 74 and the winding 75 constitute one inductance element, and the core 74 and the winding 76 constitute another inductance element.

The first parallel resonance circuit 79 and the second parallel resonance circuit 80 have different resonance characteristics. In particular, the resonance frequency of the first parallel resonance circuit 79 and the resonance frequency of the second parallel resonance circuit 80 are different from each other. In order to make the resonance characteristics of the first parallel resonance circuit 79 and the second parallel resonance circuit 80 different, the inductance of the windings 75 and 76 must be different, or the capacitance of the capacitors 72 and 73 must be changed. Either they can be different, or both can be different.

In the composite resonance circuit according to the present embodiment, as shown in FIG. 15, two parallel resonance circuits 79 and 80 are connected in series, and these two parallel resonance circuits 79 and 80 are connected to each other. Has been compounded. Therefore, this composite resonance circuit has composite resonance characteristics in which the resonance characteristics of the two parallel resonance circuits 79 and 80 are composited.

Next, an example of a composite resonance characteristic of the composite resonance circuit according to the present embodiment will be described with reference to FIG. This example is an example in which the resonance frequencies of the parallel resonance circuits 79 and 80 are relatively close to each other. FIG. 16 shows the frequency characteristics of the absolute value of the impedance of each of the parallel resonance circuits 79 and 80 as the resonance characteristics of the parallel resonance circuits 79 and 80. In FIG. 16, reference numeral 81 indicates the characteristics of the parallel resonance circuit 79, reference numeral 82 indicates the characteristics of the parallel resonance circuit 80, and reference numeral 83 indicates the characteristics of the composite resonance circuit. Moreover, fi denotes the resonant frequency of the parallel resonant circuit 7 9, f ₂ represents the resonance frequency of the parallel resonant circuit 8 0. The absolute value of the impedance of the composite resonance circuit is the sum of the absolute values of the impedances of the parallel resonance circuits 79 and 80 for each frequency. 6510

15 In this example, the absolute value of the impedance of each of the parallel resonant circuits 79, 80 is a predetermined value (for example, one half of the maximum value of the absolute value of the impedance of any of the parallel resonant circuits 79, 80). 1) The above frequency ranges partially overlap. The frequency range in which the absolute value of the impedance of the composite resonance circuit is equal to or greater than the predetermined value is wider than the frequency range of each of the parallel resonance circuits 79 and 80.

Further, in this example, the absolute value of the impedance of the composite resonance circuit in a predetermined frequency range (for example, the frequency range in which the absolute value of the impedance in the composite resonance circuit is equal to or more than the above-mentioned predetermined value) It is larger than that of each of the resonance circuits 79, 80.

Therefore, according to the composite resonance circuit of this example, the frequency range in which the ripple voltage and the noise can be reduced can be widened and the ripple voltage and the noise can be further reduced as compared with the case where one parallel resonance circuit is used. Can be.

In this embodiment, the absolute value of the impedance of each of the parallel resonance circuits 79, 80 is a predetermined value (for example, the maximum value of the absolute value of the impedance of any of the parallel resonance circuits 79, 80). The resonance characteristics of the parallel resonance circuits 79 and 80 may be set so that the frequency ranges that are equal to or more than 2) are separated from each other. In this case, the composite resonance characteristics of the composite resonance circuit are as shown in FIG.

The composite resonance circuit according to the present embodiment is inserted in the middle of the conductive wire by connecting terminals 77 and 78 to the conductive wire. The composite resonance circuit can be used as a filter for reducing ripple voltage and noise propagating on the conductive line.

[Fifth Embodiment]

Next, a composite resonance circuit according to a fifth embodiment of the present invention will be described with reference to FIG. FIG. 17 is an explanatory diagram showing the configuration of the composite resonance circuit according to the present embodiment.

The composite resonance circuit according to the present embodiment includes: two magnetic cores 91 and 92 constituting an annular magnetic circuit; windings 93 and 94 wound around the magnetic cores 91 and 92, respectively; Capacitance 95 connected in parallel with winding 93 and winding connected in parallel with winding 94 3 06510

16 capacitors 96. A terminal 97 is connected to one end of the winding 93. The other end of the winding 93 is connected to one end of the winding 94. The terminal 98 is connected to the other end of the winding 94. Therefore, the winding 93 and the winding 94 are connected in series. The equivalent circuit of the composite resonance circuit according to the present embodiment is the same as the equivalent circuit in the fourth embodiment shown in FIG.

In the present embodiment, the magnetic core 91, the winding 93, and the capacitor 95 constitute a first parallel resonance circuit 101, and the magnetic core 92, the winding 94, and the capacity 96 are the first parallel resonance circuit 101. Two parallel resonance circuits 102 are formed.

The first parallel resonance circuit 101 and the second parallel resonance circuit 102 have different resonance characteristics from each other. In particular, the resonance frequency of the first parallel resonance circuit 101 and the resonance frequency of the second parallel resonance circuit 102 are different from each other. In order to make the resonance characteristics of the first parallel resonance circuit 101 and the second parallel resonance circuit 102 different, the inductances of the windings 93 and 94 should be different or the capacitances 95 and 96 should be different. The capacities can be different, or both can be different.

In the composite resonance circuit according to the present embodiment, two parallel resonance circuits 101 and 102 are connected in series, and the two parallel resonance circuits 101 and 102 are combined. Therefore, this composite resonance circuit has a composite resonance characteristic obtained by combining the resonance characteristics of the two parallel resonance circuits 101 and 102.

The composite resonance characteristics of the composite resonance circuit according to the present embodiment are the same as those of the fourth embodiment, and are as shown in FIGS. 16 and 6, for example.

Other configurations, operations, and effects of the present embodiment are the same as those of the fourth embodiment.

[Sixth embodiment]

Next, a filter according to a sixth embodiment of the present invention will be described. The filter according to the present embodiment reduces a signal in a predetermined frequency range. Note that the signal referred to here includes a ripple voltage and noise. The filter according to the present embodiment includes the composite resonance circuit of the present invention. That is, the filter according to the present embodiment has different resonance characteristics from each other, includes a plurality of composite parallel resonance circuits, and has a composite resonance obtained by combining the resonance characteristics of the respective parallel resonance circuits. Has characteristics. The filter according to the present embodiment uses the composite resonance characteristic to reduce a signal in a predetermined frequency range.

First, the configuration of the noise suppression circuit including the filter according to the present embodiment will be described with reference to FIG. The noise suppression circuit 111 is inserted in the middle of two conductive wires 113a and 113b connected to the electronic device 112 as a noise source. The conductive wires 113a and 113b are connected to a power line 114 that carries AC power or DC power. The power supply line 114 includes two conductive lines 114a and 114b. The conductive wires 113a and 113b are connected to the conductive wires 114a and 114b, respectively. The electronic device 112 receives power supply from the power supply line 114 via the conductive wires 113a and 113b. The electronic devices 112 are, for example, switching power supplies.

The noise suppression circuit 111 suppresses noise generated from the electronic device 112 and transmitted on the conductive lines 113a and 113b. The noise suppression circuit 111 includes a low-frequency noise reduction circuit 120 as a filter according to the present embodiment, and a high-frequency noise reduction circuit 180. The low-frequency noise reduction circuit 120 is connected to the electronic device 112 via conductive wires 113a and 113b. The high-frequency noise reduction circuit 180 is cascaded to the low-frequency noise reduction circuit 120, and is connected to the conductive wires 114a and 114b of the power supply line 114. Note that the arrangement of the low-frequency noise reduction circuit 120 and the high-frequency noise reduction circuit 180 between the electronic device 112 and the power supply line 114 may be opposite to the arrangement shown in FIG. Good.

The high-frequency noise reduction circuit 180 mainly reduces noise in the first frequency range. The low-frequency noise reduction circuit 120 mainly reduces noise in a second frequency range including a frequency lower than a frequency in the first frequency range. The first frequency range is a range including, for example, a range of 1 MHz to 30 MHz. The second frequency range is, for example, a range of 0 to 1 °, or a part of the range. Low-frequency noise reduction circuit 120 as a filter according to the present embodiment reduces noise in the second frequency range as a signal in a predetermined frequency range.

The low-frequency noise reduction circuit 120 and the high-frequency noise reduction circuit 180 are housed in a housing 115 that functions as a ground for them. Low frequency noise reduction circuit 1 PC orchid hire 10

18

The portion connected to the ground in 20 and the high-frequency noise reduction circuit 180 is connected to the ground line 113c. The ground line 113c is electrically connected to the housing 115. The high-frequency noise reduction circuit 180 may be arranged at a position closer to the housing 115 than the low-frequency noise reduction circuit 120. When the power supply line 114 has a ground wire in addition to the conductors 114a and 114b, the ground wire 113c is electrically connected to the ground wire of the power supply line 114. It may be.

The noise suppression circuit 111 may be separate from the electronic device 112 or may be integrated therewith. When the noise suppression circuit 111 is separate from the electronic device 112, the housing 115 is a dedicated housing for the noise suppression circuit 111. When the noise suppression circuit 1 1 1 is integrated with the electronic device 1 1 2, the housing 1 1 5 may be the housing of the electronic device 1 1 2 or the electronic device 1 1 2 It may be a dedicated housing for the noise suppression circuit 111 housed in the housing. The part of the electronic device 112 connected to the ground may be connected to the ground line 113c.

Next, the configuration of the filter according to the present embodiment, that is, the low-frequency noise reduction circuit 120 will be described with reference to FIG. The low-frequency noise reduction circuit 120 reduces normal mode noise and common mode noise propagating through the conductive lines 113a and 113b. Here, the low-frequency noise reduction circuit 120 is described as being disposed between the electronic device 112 and the high-frequency noise reduction circuit 180. The low-frequency noise reduction circuit 1 2 0 has two terminals 1 2 1 a and 1 2 1 b connected to the electronic device 1 1 2 and the two terminals 1 2 connected to the high-frequency noise reduction circuit 1 80 2 a and 12 2 b. Terminals 121a and 122a are connected by conductive wire 113a. Terminals 121b and 122b are connected by conductive wire 113b. The low-frequency noise reduction circuit 120 further includes a composite resonance circuit 1 23 inserted between the terminals 121 a and 122 a in the conductive wire 113 a, and terminals 122 b and 122 ba. And a composite resonance circuit 124 inserted between the conductive wires 113 b in between. The composite resonance circuits 123 and 124 have the same configuration. As the composite resonance circuits 123 and 124, any of the composite resonance circuits of the first to fifth embodiments is used.

According to the low-frequency noise reduction circuit 120, the conductive lines 113 a and 113 b The normal mode noise and the common mode noise in the second frequency range can be reduced. The low-frequency noise reduction circuit 120 may include only one of the composite resonance circuits 123 and 124 to reduce only normal mode noise.

Next, an example of a specific circuit configuration of the high-frequency noise reduction circuit 180 will be described with reference to FIG. The high-frequency noise reduction circuit 180 shown in FIG. 20 reduces common mode noise propagating through the conductive lines 113a and 113b. Here, the high-frequency noise reduction circuit 180 is described as being disposed between the low-frequency noise reduction circuit 120 and the power supply line 114. The high-frequency noise reduction circuit 180 is composed of two terminals 18 1 a and 18 1 b connected to the low-frequency noise reduction circuit 120 and the conductive lines 114 a and 1 of the power supply line 114. It has two terminals 182a and 182b connected to 14b. Terminals 18 1 a and 182 a are connected by a conductive wire 113 a. Terminals 18 1 b and 182 b are connected by a conductive wire 113 b. The high-frequency noise reduction circuit 180 is further disposed at a predetermined position of the conductive lines 113a and 113b, and detects common mode noise propagating through the conductive lines 113a and 113b. Detection circuit 184, an anti-phase signal generation circuit 185 for generating an anti-phase signal that is an anti-phase signal to the noise detected by the detection circuit 184, and conductive lines 1 13 a, 1 13 Injection circuit 18 which is arranged at a position different from the detection circuit 184 in b, and injects the negative-phase signal generated by the negative-phase signal generation circuit 185 into the conductive lines 113 a and 113 b. 6 and a position where the detection circuit 184 is arranged and the position where the injection circuit 186 is arranged in the conductive lines 113a and 113b, and the noise wave passing therethrough is provided. An impedance element 187 having an impedance to reduce the high value, and an impedance element provided between the negative-phase signal generation circuit 185 and the injection circuit 186 And a 1 8 8.

In the impedance element 188, the phase difference between the noise input to the injection circuit 186 and the negative phase signal injected into the conductive lines 113a and 113b by the injection circuit 186 approaches 180 °. In this way, the phase of the negative phase signal is adjusted. In addition, the impedance element 188 allows the peak value of the negative-phase signal injected into the conductive lines 113a and 113b by the injection circuit 186 to be a value of the noise input to the injection circuit 186. Wave height It can also be adjusted to approach the value.

The detection circuit 184 includes a capacitor 184a having one end connected to the conductive line 113a and the other end connected to the input terminal of the negative-phase signal generation circuit 185, and one end connected to the conductive line 113. b and a capacitor 184 b connected at the other end to the input terminal of the antiphase signal generation circuit 185. Capacitors 184a and 184b allow high-frequency components of voltage fluctuations in conductive lines 113a and 113b to pass, and block low-frequency components including the frequency of AC power. The injection circuit 186 has one end connected to the output end of the impedance element 188, the other end connected to the conductive line 113a, a capacitor 186a, and one end connected to the output of the impedance element 188. And a capacitor 186 b connected to the other end and the other end connected to the conductive line 113 b. In this example, the injection circuit

The 186 gives the same voltage change corresponding to the negative-phase signal to the conductive lines 113a and 113b via the capacitors 186a and 186b.

The antiphase signal generating circuit 185 has a transformer 189. One end of the primary winding of the transformer 189 is connected to the capacitors 184a and 184b. The other end of the primary winding of the transformer 189 is connected to ground together with one end of the secondary winding of the transformer 189. The other end of the secondary winding of the transformer 189 is connected to the impedance element 188. Common mode choke coil for impedance element 1 8 7

A line choke coil 191 or an impedance element having a phase characteristic equivalent thereto is used as the impedance element 188. The capacitances of the capacitors 184a, 184b, 186a, 186b are set so that, for example, the leakage current value falls within a predetermined standard value. Specifically, the capacities of the capacitors 184a, 184b, 186a, and 186b are, for example, in the range of 10 to 20 and OOOpF.

It is ideal that the turns ratio of the primary winding and the secondary winding of the transformer 189 is 1: 1, but the turns ratio is changed in consideration of the signal attenuation in the transformer 189. You may.

Next, the operation of the high-frequency noise reduction circuit 180 shown in FIG. 20 will be described. In this high-frequency noise reduction circuit 180, the conductive lines 113a and 113b on the detection circuit 184 side than the impedance element 187 (hereinafter simply referred to as the conductive lines 1 84 on the detection circuit 184 side) We say 1 3 a, 1 1 3 b. The noise generated above passes through the impedance element 187, and the conductive wires 1 13a and 1 13b on the injection circuit 1 86 side of the impedance element 1 87 (hereinafter simply referred to as the injection circuit). When it flows into the conductive lines 1 13a and 1 13b on the 186 side, the peak value of noise on the conductive lines 1 13a and 1 13b on the injection circuit 186 is detected. It becomes smaller than the peak value of the noise on the conductive wires 1 13 a and 1 13 b on the circuit 184 side. Also, in the high-frequency noise reduction circuit 180, the impedance element 187 causes the noise peak value on the conductive lines 113a and 113b on the detection circuit 184 side and the conductive value on the injection circuit 186 side to be higher. The state where the noise peak values on the lines 113a and 113b differ from each other can be maintained.

In the high-frequency noise reduction circuit 180 shown in FIG. 20, the detection circuit 184 detects the common mode noise on the conductive lines 113a and 113b. Then, the anti-phase signal generation circuit 185 generates an anti-phase signal which is a signal of an anti-phase to the noise detected by the detection circuit 184. Further, the injection circuit 186 injects the antiphase signal generated by the antiphase signal generation circuit 185 into the conductive lines 113a and 113b. As a result, the common mode noise on the conductive lines 113a and 113b on the injection circuit 186 side is canceled.

Note that the peak value of the noise after passing through the impedance element 187 is smaller than the peak value of the noise before passing through the impedance element 187. Therefore, the peak value of the negative-phase signal injected into the conductive lines 113a and 113b by the injection circuit 186 is converted into the noise input to the injection circuit 186 after passing through the impedance element 187. It is necessary to make an adjustment so as to be close to the peak value.

In the fe high-frequency noise reduction circuit 180 shown in FIG. 20, the impedance input to the injection circuit 186 by the impedance element 188 and the conductive line 113 a, The phase difference between the opposite phase signal injected into 113b and 180 ° can be made close to 180 °, and the reverse circuit injected into conductive lines 113a and 113b by injection circuit 186. The peak value of the phase signal can be made close to the peak value of the noise input to the injection circuit 186. Therefore, according to the high-frequency noise reduction circuit 180, the noise on the conductive lines 113a and 113b on the injection circuit 186 side can be reduced more effectively. Note that the present invention is not limited to the above embodiments, and various modifications are possible. For example, in each embodiment, a composite resonance circuit is formed by combining two parallel resonance circuits. However, in the present invention, a composite resonance circuit may be formed by combining three or more parallel resonance circuits. .

As described above, according to the composite resonance circuit of the present invention, the ripple voltage and noise generated by the power conversion circuit are reduced by using the composite resonance characteristics obtained by combining the resonance characteristics of a plurality of parallel resonance circuits. can do. Further, in the present invention, noise having a certain frequency width can be reduced, and ripple voltage and noise having different frequencies can be reduced at the same time. Further, according to the present invention, the ripple voltage and the noise are reduced by using the composite resonance characteristics, so that the size can be reduced. Therefore, according to the present invention, it is possible to realize a composite resonance circuit that can be used as a filter for reducing a ripple voltage and noise generated by a power conversion circuit and that can be reduced in size. In the above, a plurality of parallel resonance circuits may be configured using one inductance element including a plurality of inductance elements and one or more capacitors connected to the inductance element. In this case, the size of the composite resonance circuit can be further reduced.

Further, according to the filter of the present invention, the same effect as that of the composite resonance circuit of the present invention can be obtained.

Based on the above description, it is apparent that various aspects and modifications of the present invention can be implemented. Therefore, within the scope equivalent to the following claims, the present invention can be carried out in a form other than the above-described best mode.

Claims

The scope of the claims

1. A composite resonance circuit comprising a plurality of composite parallel resonance circuits having different resonance characteristics from each other and having composite resonance characteristics obtained by combining the resonance characteristics of the respective parallel resonance circuits.

2. The plurality of parallel resonance circuits include one inductance element including a plurality of inductance elements, and one or more capacitors connected to the inductance elements. Composite resonance circuit.

3. The inductance element has one magnetic core and a plurality of windings wound on the magnetic core, and a plurality of inductance elements are formed by these. A separate capacitor is connected to each winding. 3. The composite resonance circuit according to claim 2, wherein:

4. The inductance element has a plurality of bonded magnetic cores, and a plurality of windings wound around each magnetic core, and a plurality of inductance elements are configured by these. 3. The composite resonance circuit according to claim 2, wherein a capacity is connected.

5. The composite resonance circuit according to claim 4, wherein the plurality of magnetic cores have different characteristics from each other.

6. The inductance element has a plurality of magnetic cores having different characteristics from each other, and one winding wound on the plurality of magnetic cores, and these constitute a plurality of inductance elements. 3. The composite resonance circuit according to claim 2, wherein one capacitor is connected.

7. The composite resonance circuit according to claim 1, wherein the plurality of parallel resonance circuits include a plurality of windings and a capacity connected to each winding in parallel.

8. The composite resonance circuit according to claim 7, wherein the plurality of windings are connected in series.

9. The composite resonance circuit according to claim 8, wherein the plurality of parallel resonance circuits further include one magnetic core on which the plurality of windings are wound.

10. The composite resonance circuit according to claim 8, wherein the plurality of parallel resonance circuits further include a plurality of magnetic cores each wound with each of the windings.

11. The frequency range in which the absolute value of the impedance of each of the plurality of parallel resonance circuits is equal to or more than a predetermined value partially overlaps, and the frequency range in which the absolute value of the impedance of the composite resonance circuit is equal to or more than the predetermined value. 2. The composite resonance circuit according to claim 1, wherein the frequency range is wider than the frequency range of each parallel resonance circuit.

12. The frequency range in which the absolute value of the impedance of each of the plurality of parallel resonance circuits is equal to or more than a predetermined value is separated from each other, and the frequency range in which the absolute value of the impedance of the composite resonance circuit is equal to or more than the predetermined value is: 2. The composite resonance circuit according to claim 1, comprising the frequency range of each parallel resonance circuit.

13. The absolute value of the impedance of the composite resonance circuit in a predetermined frequency range is larger than that of each of the plurality of parallel resonance circuits in the frequency range. Composite resonance circuit.

1 4. A filter for reducing a signal in a predetermined frequency range,

A filter comprising a plurality of combined parallel resonance circuits having different resonance characteristics from each other, and having a composite resonance characteristic obtained by combining resonance characteristics of the respective parallel resonance circuits.