JP2007235580A - Noise filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a filter by removing a normal mode choke coil. <P>SOLUTION: In first and second common mode choke coils to suppress propagation of common mode noise constituting EMI noise to the power source side, a first magnetic substance core 38 having a pair of magnetic legs, with projection parts formed on both edges thereof in the first common mode choke coil 34 and a second magnetic substance core 39 having the same structure as that of the first magnetic substance core 38 and arranged so that projection parts on both edges may be opposite to the projection part on both edges of the first magnetic substance core by a gap 42 is formed in a second common mode choke coil 35. Furthermore, winding directions of winding wire in the same phase wound to each magnetic leg opposite to each other via gaps of the first and the second magnetic substance cores is reversed and high impedance to normal mode noise is obtained by a magnetic flux of a magnetic circuit formed by the wire wound in the same phase. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a noise filter that is provided in an electric circuit connecting a power source and a load side device and suppresses propagation of electromagnetic interference noise (electro-magnetic interference noise, hereinafter abbreviated as EMI noise) generated in the load side device to the power source side. About.

  For example, in order to control the rotational operation of a motor as a load driven by alternating current with high accuracy, instead of directly applying alternating current from the alternating current power source to the motor, the alternating current output from the alternating current power source is converted by a converter (rectifier). Once converted to direct current, this direct current is converted back to alternating current by an inverter and supplied to the motor. Then, each switching element constituting the inverter is subjected to high-speed switching control with a PWM (pulse width modulation) signal, thereby controlling the rotation of the motor by changing the frequency and voltage of the alternating current applied to the motor.

  In such a power conversion device including a converter and an inverter, EMI noise accompanying a high-speed switching operation is generated in the inverter. Among these EMI noises, conduction noise flowing through the power supply line and the ground may be adversely affected, for example, by being transmitted to other devices having a common power supply.

  For example, when the AC power source is a single-phase AC power source, the conduction noise includes a common mode noise that propagates between the electric circuit composed of the R phase and the S phase that connect the AC power source and the power converter, and the ground, Two types of noise, normal mode noise propagating between the R phase and the S phase, are included, and a noise filter is generally used for these measures (see, for example, Non-Patent Document 1).

  As shown in the power supply system of FIG. 13, for example, an electric circuit 4 composed of an R phase and an S phase connecting a single-phase AC power source 1 having a rated voltage of 200 V between phases and a power conversion device 3 to which a load 2 such as a motor is connected. In addition, a noise filter 5 for suppressing EMI noise is provided. In the power converter 3, as described above, the alternating current passing through the noise filter 5 is converted into direct current by the converter 6, the ripple component is removed by the smoothing capacitor 7, and this direct current is converted into alternating current by the inverter 8. Supply to load 2.

  FIG. 14 is a circuit configuration diagram of the noise filter 5. Two common mode choke coils 13 and 14 are inserted in series on the wires 12a and 12b connecting the R-phase and S-phase power supply side terminals 10a and 10b and the R-phase and S-phase load-side terminals 11a and 11b. Yes. In each common mode choke coil 13, 14, as shown in FIG. 15, R-phase and S-phase windings 17 a, 18 a, 17 b, 18 b are wound around annular cores 15, 16.

  Further, normal mode choke coils 19 a and 19 b are inserted in the power supply side wires 12 a and 12 b of the common mode choke coil 13. An interphase capacitor 20 is provided between the power supply side terminals 10a and 10b, and an interphase capacitor 21 is also provided between the load side terminals 11a and 11b. The interphase capacitors 20 and 21 are interphase capacitors having specifications satisfying safety standards of withstand voltage and current with respect to a rated voltage of 200 V between phases.

  Further, a ground capacitor 23 a is provided between the R-phase line 12 a at the connection point of the common mode choke coils 13 and 14 and the ground 22, and a ground capacitor 23 b is provided between the S-phase line 12 b and the ground 22 at the connection point. Yes. Further, ground capacitors 24 a and 24 b are provided between the R-phase and S-phase load-side terminals 11 a and 11 b and the earth 22. Each of the grounding capacitors 23a, 23b, 23a, and 23b is a grounding capacitor having a specification that satisfies safety standards of withstand voltage and withstand current with respect to a rated voltage of 200V between the phase and the ground.

  The earth 22 is the potential of the load 2, the casing of the power conversion device 3, the neutral point, and the ground (underground).

  In such a noise filter 5, the common mode choke coils 13 and 14 exhibit high impedance with respect to common mode noise, and the ground capacitors 23a, 23b, 24a and 24b exhibit low impedance. For this reason, the common mode noise propagating between the EMI noise lines 12a and 12b and the ground 22 that is about to flow from the power conversion device 3 to the single-phase AC power source 1 is not transmitted to the single-phase AC power source 1 side having a high impedance. The low-impedance grounding capacitors 23a, 23b, 24a and 24b are bypassed and returned to the power converter 3 side.

  On the other hand, the normal mode choke coils 19a and 19b have a high impedance and the interphase capacitors 21 and 20 have a low impedance with respect to the normal mode noise of the EMI noise that flows from the power converter 3 to the single-phase AC power source 1. Thus, the interphase capacitors 21 and 20 are bypassed, and are returned to the power converter 3 side without being transmitted to the single-phase AC power source 1 as in the case of the common mode noise.

Patent Document 1 discloses a technique of a hybrid choke coil that enables countermeasures against common mode noise and normal mode noise.
Japanese Patent Laid-Open No. 2001-230120 "Electrotechnical Technical Report No. 545 Power Electronics" P22, Fig. 2.34 The Electrotechnical Society Electromagnetic Disturbance Cooperation Research Committee for Semiconductor Power Converters May 1995

  However, the noise filter 5 shown in FIGS. 14 and 15 also has the following problems that should still be solved.

  That is, in order to suppress two types of noise, ie, common mode noise and normal mode noise of EMI noise generated from the power converter 3, common mode choke coils 14 and 13 and normal mode choke coils 19a, 19b is required. Therefore, there is a concern that the noise filter becomes large and the number of parts increases.

  As a method for avoiding such a situation, a method of reducing the number of parts by replacing the leakage inductance of the common mode choke coil 13 with the normal mode choke coils 19a and 19b is also used. In order to ensure the necessary leakage inductance with a sufficiently high impedance, the inductance of the common mode choke coil 13 must be higher than the inductance necessary for the common mode noise. Therefore, the common mode choke coils 14 and 13 are increased in size, and the noise filter 5 cannot be effectively reduced in size.

  The present invention has been made in view of such circumstances, and provides a noise filter that can remove the normal mode choke coil without increasing the size of the common mode choke coil, reduce the number of components, and realize downsizing. The purpose is to do.

  In order to solve the above problems, the present invention is provided in an electric circuit connecting a single-phase AC power supply and a load-side device, and suppresses propagation of electromagnetic interference noise (EMI noise) generated in the load-side device to the single-phase AC power supply. In the noise filter, a first phase winding and a second phase winding are wound in opposite directions on a pair of magnetic legs in a first magnetic core having a pair of magnetic legs with protrusions formed at both ends. The first common mode choke coil on the power source side and the first magnetic core have the same configuration, and the protrusions at both ends face the protrusions at both ends of the first magnetic core via a gap. The pair of magnetic legs of the second magnetic core arranged in this way, the first phase winding and the second phase winding are opposite to each other and of the same phase of the first common mode choke coil The second common mode on the load side wound in the opposite direction to the winding A choke coil, a pair of interphase capacitors provided between a power supply side terminal and a load side terminal so as to sandwich at least one common mode choke coil in the first and second common mode choke coils, and a second common mode A pair of grounding capacitors provided between each phase of the load side terminal of the choke coil and the ground, and each phase and the ground at the connection point of the first common mode choke coil and the second common mode choke coil And a pair of grounding capacitors provided therebetween.

  In the noise filter configured as described above, since the first phase and second phase windings are wound in opposite directions on the pair of magnetic legs of the first common mode choke coil, A magnetic circuit is formed by the body core and the first-phase and second-phase windings, and has a high impedance to the common mode noise propagating between the electric circuit and the ground in the EMI noise generated in the load side device. Similarly, in the second common mode choke coil, a magnetic circuit is formed by the second magnetic core and the first and second phase windings, and the electric circuit and ground in the EMI noise generated in the load side device are connected. High impedance against propagating common mode noise. Each grounding capacitor exhibits a low impedance. For this reason, the common mode noise is not transmitted to the high-impedance single-phase AC power supply side, but bypasses the low-impedance ground capacitor and returns to the load-side device.

  Also, protrusions at both ends of the magnetic legs around which the first phase winding of the first magnetic core of the first common mode choke coil is wound, and the second magnetic core of the second common mode choke coil The protrusions at both ends of the magnetic leg around which the first phase winding is wound are opposed to each other through a gap. Since the magnetic legs facing each other through the gap are magnetized in the opposite directions, the facing protrusions become different magnetic poles. As a result, a magnetic circuit is formed by the first magnetic core, the second magnetic core, and the first phase windings, and the inductance due to the magnetic flux in the magnetic circuit is the first in the EMI noise generated in the load side device. High impedance with respect to the normal mode node propagating between the phase and the second phase.

  Similarly, a magnetic circuit is formed by the windings of the second phase of the first and second common mode choke coils, the first magnetic core, and the second magnetic core. Inductance becomes high impedance with respect to normal mode noise propagating between the first phase and the second phase in the EMI noise generated in the load side device. For this reason, the normal mode noise is not transmitted to the single-phase AC power supply side having high impedance, but returns to the load side device via the low-impedance interphase capacitor.

  As described above, the common mode choke coil has the function of suppressing normal mode noise in addition to the function of suppressing the original common mode noise. There is no need to provide.

  According to another invention, in the above-described noise filter, the first common mode choke coil, the second common mode choke coil, and a pair of interphase capacitors in the above invention are provided.

  Furthermore, a grounding capacitor provided between one phase of the load side end of the second common mode choke coil and the ground, and a connection point between the first common mode choke coil and the second common mode choke coil. A grounding capacitor provided between the other phase and the ground.

  In the noise filter configured as described above, one grounding capacitor is provided between each phase and the ground. In this case, the capacity of each grounding capacitor may be set to double that of the grounding capacitor of the previous invention.

  According to another invention, in the above-described noise filter, the first common mode choke coil, the second common mode choke coil, and a pair of interphase capacitors in the above invention are provided. Furthermore, a grounding capacitor provided between one phase of the load side terminal of the second common mode choke coil and the ground, and a connection point between the first common mode choke coil and the second common mode choke coil. A grounding capacitor provided between the load side terminal and the same phase and ground.

  Even in such a configuration, it is possible to obtain the same effect as the above-described invention.

  According to another aspect of the present invention, the noise filter of the above-described invention includes a withstand voltage additional capacitor interposed between each ground-side terminal of each ground capacitor and the ground.

  According to another invention, in the above-described noise filter, the first common mode choke coil, the second common mode choke coil, and a pair of interphase capacitors in the above invention are provided.

  Further, an interphase capacitor having one end connected to one phase of the load side terminal of the second common mode choke coil, and the other phase at the connection point between the first common mode choke coil and the second common mode choke coil. And an interphase capacitor interposed between the other end of each interphase capacitor with one end connected to each phase and the ground.

  According to another invention, in the above-described noise filter, the first common mode choke coil, the second common mode choke coil, and a pair of interphase capacitors in the above invention are provided. Further, an interphase capacitor having one end connected to one phase of the load side terminal of the second common mode choke coil, and a load side terminal at a connection point between the first common mode choke coil and the second common mode choke coil And an interphase capacitor having one end connected to the same phase and a grounding capacitor interposed between the other end of each interphase capacitor and one end connected to each phase.

  Another invention is a noise filter that is provided in an electric circuit connecting a DC power source and a load side device and suppresses propagation of electromagnetic interference noise generated in the load side device to the DC power source. A first common mode choke coil on the power source side in which a first phase winding and a second phase winding are wound in opposite directions on the pair of magnetic legs in the first magnetic core having a pair of magnetic legs; The second magnetic core having the same configuration as the first magnetic core, and having the protruding portions at both ends opposed to the protruding portions at both ends of the first magnetic core via a gap The first-phase winding and the second-phase winding are wound around the pair of magnetic legs so that the first-phase winding and the second-phase winding are opposite to each other and also opposite to the same-phase winding of the first common mode choke coil. Load-side second common mode choke coil, first magnetic core and second Provided between the power supply side terminals and the load side terminals so as to sandwich at least one common mode choke coil in the first and second common mode choke coils and the ferromagnetic material inserted in the gap with the magnetic core. A pair of interphase capacitors, a grounding capacitor provided between one phase of the load side terminal of the second common mode choke coil and the ground, and a first terminal having one end connected to the same phase as the load side terminal A grounding capacitor provided between one phase at the connection point between the common mode choke coil and the second common mode choke coil and the ground.

  In the noise filter configured as described above, since direct current flows through the first and second common mode choke coils, the magnetic flux of each magnetic circuit formed by the first and second common mode choke coils is large. Since the DC magnetic flux component is superposed, each magnetic core may be magnetically saturated. Therefore, a sufficiently high impedance against normal mode noise cannot be obtained.

  Therefore, by inserting a ferromagnetic material such as a magnet in the gap between the first magnetic core and the second magnetic core, a reverse DC magnetic field is applied to saturate the magnetic circuit magnetic flux. Suppressed.

  In the present invention, the normal mode choke coil can be removed without increasing the size of the common mode choke coil, the number of parts can be reduced, and downsizing can be realized.

  Furthermore, by appropriately combining the interphase capacitor and the ground capacitor, the number of parts can be further reduced, and further downsizing can be realized.

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

(First embodiment)
FIG. 1 is a circuit diagram showing a schematic configuration of a noise filter according to the first embodiment of the present invention. The same parts as those of the conventional noise filter shown in FIGS. 13 and 14 are denoted by the same reference numerals, and detailed description of the overlapping parts is omitted.

  In FIG. 1, for example, an R-phase line 31 a and a second phase as a first phase connecting a single-phase AC power source 1 having a rated voltage of 200 V between phases and a load-side device 33 including a load 2 such as a motor and a power converter 3. The S-phase line 31b is provided with the noise filter 32 of the first embodiment that suppresses EMI noise generated in the power conversion device 3 and propagating to the single-phase AC power supply 1 side.

  In the noise filter 32 of the first embodiment, a first common mode choke coil 34 and a second common mode choke coil 35 are interposed in series between an R phase line 31a and an S phase line 31b. The first common mode choke coil 34 on the power supply side is composed of an R phase winding 36a and an S phase winding 36b, and the second common mode choke coil 35 on the load side is an R phase winding 37a and an S phase winding. 37b.

  The interphase capacitor 20 is connected between the power supply side terminals 36aa and 36bb of the first common mode choke coil 34. The interphase capacitor 21 is also connected between the load side terminals 37aa and 37bb of the second common mode choke coil 35. Further, a grounding capacitor 23 a is provided at the R-phase connection point 43 a and the ground 22 of the first common mode choke coil 34 and the second common mode choke coil 35, and grounding is performed between the S-phase connection point 43 b and the ground 22. A capacitor 23b is provided.

  In addition, each grounding capacitor 23a, 24a, 24b has the same configuration and the same specification with the specifications satisfying the safety standards of withstand voltage of 250 to 270V and withstand current with respect to the rated voltage of 200V between the phase and the ground. This is a grounding capacitor.

  The interphase capacitors 20 and 21 are interphase capacitors having the same configuration and the same specifications having specifications that satisfy a withstand voltage of 250 to 270 V and a withstand current safety standard with respect to a rated voltage of 200 V between phases.

  Specific configurations of the first common mode choke coil 34 and the second common mode choke coil 35 will be described with reference to FIGS. FIG. 2 is an assembled perspective view showing a first magnetic core 38 incorporated in the first common mode choke coil 34 and a second magnetic core 39 incorporated in the second common mode choke coil 35. is there.

  As shown in FIG. 2A, two parallel magnetic legs 38a and 38b are formed on the first magnetic core 38, and the magnetic legs 38a and 38b are respectively connected to both ends of the magnetic legs 38a and 38b. Common projecting portions 40a and 40b projecting in a direction perpendicular to 38a and 38b are formed. Similarly, the second magnetic core 39 is formed with two parallel magnetic legs 39a and 39b, and protrudes in the direction perpendicular to the magnetic legs 39a and 39b at both ends of each magnetic leg 39a and 39b. Common protrusions 41a and 41b are formed.

  Then, as shown in FIG. 3, the R-phase winding 36a, the S-phase winding 36b, the R-phase winding 37a, and the S-phase winding 37b are wound around the magnetic legs 38a, 38b, 39a, 39b. As shown in FIG. 2B, the first magnetic core 38 and the second magnetic core 38 are such that the respective protrusions 40 a, 40 b, 41 a, 41 b face each other through the gap 42. It is arranged.

  FIG. 3B is a front view of the first and second common mode choke coils 34 and 35, FIG. 3C is a side view, and FIG. 3A is the first view of FIG. FIG. 3 is a cross-sectional view taken along line AA ′ of the first and second common mode choke coils 34 and 35.

  As illustrated, an R-phase winding 36a and an S-phase winding 36b are wound around the magnetic legs 38a and 38b of the first magnetic core 38 in opposite directions. Similarly, an R-phase winding 37a and an S-phase winding 37b are wound around the magnetic legs 39a and 39b of the second magnetic core 39 in opposite directions. Furthermore, the R-phase winding 36a and the R-phase winding 37a connected at the connection point 43a are wound in opposite directions. Similarly, the S-phase winding 36b and the S-phase winding 37b connected at the connection point 43b are wound in opposite directions.

In the first and second common mode choke coils 34 and 35 combined in this way, a magnetic circuit (44) is formed by the first magnetic core 38, the R phase winding 36a, and the S phase winding 36b. The second magnetic core 39, the R-phase winding 37a, and the S-phase winding 37b form a magnetic circuit 44 indicated by a broken line in FIG. The magnetic circuit 44 generates a magnetic flux φ _C.

  In this way, the inductance due to the magnetic flux in the magnetic circuit 44 formed by the R-phase winding 36 a and the S-phase winding 36 b and the R-phase winding 37 a and the S-phase winding 37 b causes EMI noise generated in the load side device 30. It becomes a high impedance with respect to the common mode noise which propagates between the R phase wire 31a, the S phase wire 31b, and the earth 22 in

  Furthermore, the protrusions 40a and 40b at both ends of the magnetic leg 38a around which the R-phase winding 36a of the first magnetic core 38 is wound and the magnetic field around which the phase winding 37a of the second magnetic core 39 is wound. The protrusions 41a and 41b at both ends of the leg 39a are opposed to each other through the gap 42. Since the magnetic legs 38a and 39a facing each other through the air gap 42 are magnetized in opposite directions, the projecting portions 40a and 40b and the projecting portions 41a and 41b facing each other have different magnetic poles. As a result, a magnetic circuit (45) is formed by the magnetic legs 38a of the first magnetic core 38, the magnetic legs 39a of the second magnetic core 39, and the R-phase windings 36a and 37a.

  Similarly, the magnetic circuit 45 shown by the solid line in FIG. 3B is formed by the magnetic leg 38b of the first magnetic core 38, the magnetic leg 39b of the second magnetic core 39, and the S-phase windings 36b and 37b. Is done. The magnetic circuit 45 generates a magnetic flux φn.

  Thus, the inductance due to the magnetic flux φn in the magnetic circuit 45 straddling the first and second magnetic cores 38 and 39 propagates between the R-phase line 31a and the S-phase line 31b in the EMI noise generated in the load side device 30. High impedance against normal mode noise.

In the noise filter 32 of the first embodiment configured as described above, a common that propagates between the R-phase line 31a, the S-phase line 31b and the ground 22 in the EMI noise generated in the load-side device 30 to the single-phase AC power supply 1 side. The mode noise is high because of the high impedance of the inductance due to the magnetic flux φ _C of the magnetic circuit 44 formed across the R-phase winding and the S-phase winding in the first and second common mode choke coils 34 and 35, respectively. The low-impedance grounding capacitors 23 a, 23 b, 24 a, and 24 b are bypassed and returned to the load-side device 30 without being transmitted to the single-phase AC power source 1 side that becomes the impedance.

  In addition, normal mode noise that propagates between the R-phase line 31a and the S-phase line 31b to the single-phase AC power supply 1 side in the EMI noise generated in the load side device 30 straddles the first and second magnetic cores 38 and 39. Due to the high impedance of the inductance due to the magnetic flux φn of the magnetic circuit 45 formed by two windings of the same phase formed in this way, each low-impedance interphase capacitor 21 is not transmitted to the single-phase AC power supply 1 side that becomes a high impedance. , 20 is bypassed and returned to the load side device 30.

  As described above, since the first and second common mode choke coils 34 and 35 have the function of suppressing normal mode noise in addition to the function of suppressing normal common mode noise, a normal mode is separately provided. There is no need to provide a normal mode choke coil to suppress noise.

  In addition, this invention is not limited to the noise filter 32 of 1st Embodiment mentioned above. For example, the interphase capacitor 20 connected between the power supply side terminals 36aa and 36bb or the interphase capacitor 21 connected between the load side terminals 37aa and 37bb is connected to the connection point of the first and second common mode choke coils 34 and 35. It is also possible to move between 43a and 43b.

(Second Embodiment)
FIG. 4 is a circuit diagram showing a schematic configuration of a noise filter according to the second embodiment of the present invention. The same parts as those of the noise filter 32 of the first embodiment shown in FIG.

  In the noise filter 32a of the second embodiment, the ground capacitor 23b provided between the S-phase intermediate point 43b and the ground 22 and the load terminal 37aa and the ground 22 in the noise filter 32 of the first embodiment of FIG. The provided grounding capacitor 24a is removed.

  Furthermore, the grounding capacitor 23a provided between the R-phase intermediate point 43a and the earth 22 in the noise filter 32 of the first embodiment is changed to a grounding capacitor 24A whose capacitance (capacitor capacity) is set to double. In addition, the grounding capacitor 24b provided between the load terminal 37bb and the earth 22 in the noise filter 32 of the first embodiment is changed to a grounding capacitor 24B having a capacitance (capacitor capacity) set to double.

  Other configurations are almost the same as the configuration of the noise filter 32 of the first embodiment shown in FIG.

In the noise filter 32a of the second embodiment configured as described above, the first and second common mode choke coils 34 and 35 are the first and second in the noise filter 32 of the first embodiment shown in FIG. The common mode choke coils 34 and 35 have the same configuration and the interphase capacitors 20 and 21 have the same configuration. Therefore, the common mode noise and the normal mode noise of the MEI noise generated in the load side device 30 are the same as those in the magnetic circuit described above. Propagation to the single-phase AC power source 1 side is suppressed by the high impedance due to the magnetic fluxes φ _C and φ n of 44 and 45 and the presence of the grounding capacitors 23A and 24B and the interphase capacitors 20 and 21.

  Further, in the noise filter 32a of the second embodiment, the noise component propagating through the S-phase line 31b in the common mode noise among the MEI noise generated in the load side device 30 is directly passed through the grounding capacitor 24B to the earth 22 To the load side device 30.

  In addition, the noise component propagating through the R-phase line 31a in the common mode noise among the MEI noise generated in the load side device 30 bypasses the interphase capacitor 21 and flows to the ground capacitor 24B, to the single phase AC power source 1 side. Propagation of common mode noise is suppressed. In addition, a minute noise component that has passed through the R phase winding 37a of the second common mode choke coil 35 out of the noise component propagating through the R phase line 31a in the common mode noise flows from the connection point 43a to the grounding capacitor 23A. .

  Thus, the number of ground capacitors can be reduced to half that of the noise filter 32 of the first embodiment shown in FIG. 1, the number of components of the noise filter 32a can be reduced, and the entire noise filter can be reduced in size, weight and cost. Can be manufactured.

  In addition, since the capacity | capacitance (capacitor capacity | capacitance) of ground capacitor 23A, 24B is set to 2 times the ground capacitors 23a, 23b, 24a, 24b of 1st Embodiment, the capability of noise suppression does not fall.

(Third embodiment)
FIG. 5 is a circuit configuration diagram of a noise filter according to the third embodiment of the present invention. The same parts as those of the noise filter 32a of the second embodiment shown in FIG.

  In the noise filter 32b of the third embodiment, the ground capacitor 23A between the R-phase connection point 43a of the first and second common mode choke coils 34 and 35 and the ground 22 is removed, and the first and second A ground capacitor 23B having a capacity double that of the ground capacitor 23b in the noise filter 32 of the first embodiment is provided between the S-phase connection point 43b of the common mode choke coils 34 and 35 and the ground 22. That is, in the noise filter 32b of the third embodiment, the ground capacitors 23B and 24B are connected only to the S-phase line 31b.

  Other configurations are substantially the same as those of the noise filter 32a of the second embodiment shown in FIG.

  In the noise filter 32b of the third embodiment configured as described above, the noise component propagating through the S phase line 31b in the common mode noise of the MEI noise generated in the load side device 30 passes through the ground capacitor 24B as it is. And flows to the ground 22 and returns to the load side device 30. In addition, the noise component propagating through the R-phase line 31a in the common mode noise among the MEI noise generated in the load side device 30 bypasses the interphase capacitor 21 and flows to the ground capacitor 24B, to the single phase AC power source 1 side. Propagation of common mode noise is suppressed. Of the noise component propagating through the R-phase line 31 a, the minute noise component that has passed through the R-phase winding 37 a of the second common mode choke coil 35 is the R-phase winding of the first common mode choke coil 34. 36a, the interphase capacitor 20, the S-phase winding 36b of the first common mode choke coil 34, and the connection point 43b flow to the ground capacitor 23B.

  As described above, also in the noise filter 32b of the third embodiment, the number of ground capacitors can be reduced to half as in the noise filter 32a of the second embodiment, and the number of components of the noise filter 32b can be reduced. The entire noise filter can be manufactured in a small size and at a low price.

(Fourth embodiment)
FIG. 6 is a circuit configuration diagram of a noise filter according to the fourth embodiment of the present invention. The same parts as those of the noise filter 32b of the second embodiment shown in FIG. 4 are denoted by the same reference numerals, and detailed description of the overlapping parts is omitted.

  The noise filter 32c according to the fourth embodiment receives a single-phase AC of 400V from the single-phase AC power source 1a having a rated voltage of 400V. Therefore, between the power supply side terminals 36aa and 36bb of the first common mode choke coil 34, the two interphase capacitors 20 having the specifications satisfying the safety standards of withstand voltage and current with respect to the rated voltage 200V described above. Are inserted in series. Similarly, between the load side terminals 37aa and 37bb of the second common mode choke coil 35, two interphase capacitors having specifications satisfying the safety standards of withstand voltage and current withstand for the rated voltage of 200V described above. 21 is inserted in series.

  Further, one end of the grounding capacitor 23A having the double capacity is connected to the R-phase connection point 43a of the first and second common mode choke coils 34 and 35, and the second common mode choke coil 35 is connected. One end of the grounding capacitor 24B having the double capacity is connected to the S-phase load side terminal 37bb. A withstand voltage adding capacitor 46 is inserted between the other end of each grounding capacitor 23A, 24B and the ground 22.

  Also in the noise filter 32c of the fourth embodiment configured as described above, the R-phase connection point 43a of the first and second common mode choke coils 34 and 35, and the load side terminal of the second common mode choke coil 35 37bb is connected to the ground 22 via the ground capacitors 23A and 24B and the withstand voltage additional capacitor 46, respectively, and therefore has substantially the same effect as the noise filter 32a of the second embodiment shown in FIG.

  In this case, in the noise filter 32c of the fourth embodiment shown in FIG. 6, since the grounding capacitors 23A and 24B satisfy the safety standard for withstand voltage, the withstand voltage added capacitor 46 does not need to satisfy the safety standard. Furthermore, one withstand voltage adding capacitor 46 is interposed between the lower terminals of the grounding capacitors 23 </ b> A and 24 </ b> B and the ground 22.

  This is because if the ground capacitors 23A and 24B satisfying the safety standards are independently connected to the ground 22 via the separate capacitors, the separate capacitors need to be capacitors having the same withstand voltage. This is because it is necessary to employ a replacement expensive grounding capacitor to satisfy.

  However, in the noise filter 32c of the fourth embodiment shown in FIG. 6, since only one withstand voltage capacitor 46 is employed, the connection point between the withstand voltage capacitor 46 and the grounding capacitors 23A and 24B satisfying the safety standards. Since there is only one potential, the capacity of the withstand voltage adding capacitor 46 may be any value that is twice or more that of the ground capacitors 23a, 23b, 24a, 24b described above.

  Therefore, it is not necessary to use a replacement expensive grounding capacitor satisfying the safety standard as the withstand voltage additional capacitor 46. For example, the noise filter 32c for the single-phase AC power source 1a having the rated voltage 400V that is twice the rated voltage of the normal 200v. However, a noise filter component for the single-phase AC power supply 1 having a normal rated voltage of 200 V can be used to suppress a significant increase in manufacturing costs.

(Fifth embodiment)
FIG. 7 is a circuit diagram showing a schematic configuration of a noise filter according to the fifth embodiment of the present invention. The same parts as those of the noise filter 32c of the fourth embodiment shown in FIG. 6 are denoted by the same reference numerals, and detailed description of the overlapping parts is omitted.

  The noise filter 32d according to the fifth embodiment receives a single-phase AC of 400V from the single-phase AC power source 1a having a rated voltage of 400V. Therefore, as in the fourth embodiment of FIG. 6, the power-side terminals 36aa and 36bb of the first common mode choke coil 34 satisfy the safety standards of withstand voltage and withstand current with respect to the rated voltage of 200V. Two interphase capacitors 20 having the specifications are inserted in series.

  Similarly, between the load side terminals 37aa and 37bb of the second common mode choke coil 35, two interphase capacitors having specifications satisfying the safety standards of withstand voltage and current withstand for the rated voltage of 200V described above. 21 is inserted in series.

  Furthermore, one end of an interphase capacitor 20A having a capacity double that of the interphase capacitor 20 is connected to the R-phase connection point 43a of the first and second common mode choke coils 34 and 35, so that the second common mode choke One end of an interphase capacitor 21B having a capacity double that of the interphase capacitor 21 is connected to the S-phase load side terminal 37bb of the coil 35. A ground capacitor 23C having a capacity twice that of the ground capacitor 23a is connected between the other ends of the interphase capacitors 20A and 21B and the ground 22.

  Also in the noise filter d according to the fifth embodiment configured as described above, a capacitor including the ground capacitor 23C is connected in series between the R-phase connection point 43a and the ground 22, and between the S-phase load side terminal 37bb and the ground 22. Since the circuit is inserted, it is possible to achieve substantially the same operational effects as the noise filter 32c of the fourth embodiment shown in FIG. 6 described above.

  An interphase capacitor 21C having a capacity double that of the interphase capacitors 20 and 21 may be connected between the other ends of the interphase capacitors 20A and 21B and the ground 22 instead of the ground capacitor 23C.

(Sixth embodiment)
FIG. 8 is a schematic diagram of a power supply system incorporating a noise filter according to the sixth embodiment of the present invention, and FIG. 9 is a circuit diagram showing a schematic configuration of the noise filter of the sixth embodiment. The same components as those of the noise filter 32a of the second embodiment of FIG. 4 are denoted by the same reference numerals and detailed description of the overlapping portions is omitted.

  In FIG. 8, the alternating current output from the single-phase alternating current power supply 1 having a rated voltage of 200 V between the phases is once converted into direct current by the converter 6 in the power converter 3 and the ripple component is removed by the smoothing capacitor 7. The noise is input to the noise filter 32e according to the sixth embodiment of the present invention. The direct current that has passed through the noise filter 32 e is converted into alternating current by the inverter 8 and supplied to the load 2 outside the power converter 3. And the EMI noise which generate | occur | produces in the load side apparatus 30a which consists of the inverter 8 and the load 2, and propagates to the DC power supply 47 side which consists of the smoothing capacitor 7 and the converter 6 is suppressed by the noise filter 32e.

  In the noise filter 32e of the sixth embodiment, as shown in FIG. 9, a DC power supply 47 comprising a smoothing capacitor 7 and a converter 6 is connected between the power supply side terminals 36aa and 36bb of the first common mode choke coil 34. Has been. Between the load side terminals 37aa and 37bb of the second common mode choke coil 35, a load side device 30a composed of the inverter 8 and the load 2 is connected.

  Further, in the noise filter 32e of the sixth embodiment, as shown in FIG. 10, the protrusions 40a and 40b of the first magnetic core 38 of the first common mode choke coil 34, and the second common mode A ferromagnetic material 48 made of, for example, a permanent magnet or the like in a frame shape from which the central portion of the rectangular plate is removed is inserted in the gap 42 between the projections 41a and 4b of the second magnetic core 39 of the choke coil 35. .

  Other configurations are the same as those of the noise filter 32a of the second embodiment shown in FIG.

  In the noise filter 32e of the sixth embodiment having such a configuration, direct current is supplied from the direct current power source 47 including the smoothing capacitor 7 and the converter 6 to the first and second common mode choke coils 34 and 35 of the noise filter 32e. Since the voltage is applied, a steady DC current Idc flows through the R-phase windings 36a and 37a and the S-phase windings 36b and 37b as shown in FIGS.

  When the ferromagnetic material 48 is not present, the steady DC current Idc is generated by two windings of the same phase formed across the first and second magnetic cores 38 and 39 shown in FIG. A DC magnetic flux φdc is generated that moves the magnetic flux φn of the magnetic circuit 45 in a certain direction (zero shift) in order to obtain a high impedance with respect to the normal mode node of the magnetic flux φn45 of the magnetic circuit 45 formed by lines.

  Therefore, as shown in the magnetization characteristics of the first and second magnetic cores 38 and 39 in FIG. 11, the first and second magnetic cores 38 and 39 are saturated, and the magnetic flux φn is saturated immediately. The magnetic flux (saturation magnetic field Hmax) is reached and a sufficiently high impedance against normal mode noise cannot be obtained.

  Therefore, in the noise filter 32e of the sixth embodiment, a direct current is obtained by inserting a ferromagnetic body 48 such as a magnet in the gap 43 between the first magnetic core 38 and the second magnetic core 39. By applying a DC magnetic field (DC magnetic flux) [−φdc] in the opposite direction to the direction of the DC magnetic flux φdc caused by the direct current supplied from the power supply 47, saturation of the magnetic flux φn of the magnetic circuit 45 is suppressed. Yes.

  Therefore, in the noise filter 32e of the sixth embodiment, it is possible to sufficiently suppress the common mode noise and the normal mode noise of the EMI noise generated in the load side device 30a and propagating toward the DC power supply 47 side.

1 is a circuit diagram showing a schematic configuration of a noise filter according to a first embodiment of the present invention. Assembly perspective view for explaining the configuration of the first and second common mode choke coils incorporated in the noise filter of the same embodiment The figure which shows arrangement | positioning and winding direction of each coil | winding of the 1st, 2nd common mode choke coil incorporated in the noise filter of the embodiment The circuit diagram which shows schematic structure of the noise filter concerning 2nd Embodiment of this invention. The circuit diagram which shows schematic structure of the noise filter concerning 3rd Embodiment of this invention. The circuit diagram which shows schematic structure of the noise filter concerning 4th Embodiment of this invention. The circuit diagram which shows schematic structure of the noise filter concerning 5th Embodiment of this invention. The schematic diagram which shows the electric power supply system incorporating the noise filter concerning 6th Embodiment of this invention. A circuit diagram showing a schematic configuration of the noise filter of the same embodiment Assembly perspective view for explaining the configuration of the first and second common mode choke coils in which the noise filter of the same embodiment is incorporated The figure which shows the magnetization characteristic of each magnetic body core for demonstrating the effect of the noise filter of the embodiment The figure which shows arrangement | positioning and winding direction of each coil | winding of the 1st, 2nd common mode choke coil incorporated in the noise filter of the embodiment Schematic diagram showing a power supply system incorporating a conventional noise filter Circuit diagram showing schematic configuration of the conventional noise filter Configuration diagram of each common mode choke coil incorporated in the conventional noise filter

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Single phase alternating current power supply, 2 ... Load, 3 ... Power converter, 6 ... Converter, 8 ... Inverter, 20, 21 ... Interphase capacitor, 22 ... Ground, 23a, 23A, 23b, 23B, 23C, 24a, 24A, 24b, 24B ... grounding capacitor, 30, 30a ... load side device, 32, 32a, 32b, 32c. 32d, 32e ... noise filter, 34 ... first common mode choke coil, 35 ... second common mode choke coil, 36a, 37a ... R phase winding, 36b, 37b ... S phase winding, 38 ... first Magnetic body core 39... Second magnetic body core 40 a, 40 b, 41 a, 41 b... Projection, 42 .. Gap, 43 a, 43 b .. Connection point, 44, 45 ... Magnetic circuit, 46. DC power supply, 48 ... ferromagnet

Claims (7)

In a noise filter that is provided in an electric circuit connecting a single-phase AC power source and a load-side device, and suppresses propagation of electromagnetic interference noise generated in the load-side device to the single-phase AC power source,
A power supply side in which a first phase winding and a second phase winding are wound in opposite directions on the pair of magnetic legs in the first magnetic core having a pair of magnetic legs with protrusions formed at both ends. A first common mode choke coil of
A second magnetic core having the same configuration as the first magnetic core, and having protrusions at both ends opposed to the protrusions at both ends of the first magnetic core via a gap The first-phase winding and the second-phase winding are wound around the pair of magnetic legs so as to be opposite to each other and to the same-phase winding of the first common mode choke coil. A second common mode choke coil on the turned load side;
A pair of interphase capacitors provided between the power supply side terminals and between the load side terminals so as to sandwich at least one common mode choke coil in the first and second common mode choke coils;
A pair of grounding capacitors provided between each phase of the load-side terminal of the second common mode choke coil and ground;
A noise filter, comprising: a pair of ground capacitors provided between each phase and ground at a connection point between the first common mode choke coil and the second common mode choke coil. In a noise filter that is provided in an electric circuit connecting a single-phase AC power source and a load-side device, and suppresses propagation of electromagnetic interference noise generated in the load-side device to the single-phase AC power source,
A power supply side in which a first phase winding and a second phase winding are wound in opposite directions on the pair of magnetic legs in the first magnetic core having a pair of magnetic legs with protrusions formed at both ends. A first common mode choke coil of
A second magnetic core having the same configuration as the first magnetic core, and having protrusions at both ends opposed to the protrusions at both ends of the first magnetic core via a gap The first-phase winding and the second-phase winding are wound around the pair of magnetic legs so as to be opposite to each other and to the same-phase winding of the first common mode choke coil. A second common mode choke coil on the turned load side;
A pair of interphase capacitors provided between the power supply side terminals and between the load side terminals so as to sandwich at least one common mode choke coil in the first and second common mode choke coils;
A grounding capacitor provided between one phase of the load side terminal of the second common mode choke coil and ground;
A noise filter comprising: a grounding capacitor provided between the other phase and the ground at a connection point between the first common mode choke coil and the second common mode choke coil. In a noise filter that is provided in an electric circuit connecting a single-phase AC power source and a load-side device, and suppresses propagation of electromagnetic interference noise generated in the load-side device to the single-phase AC power source,
A power supply side in which a first phase winding and a second phase winding are wound in opposite directions on the pair of magnetic legs in the first magnetic core having a pair of magnetic legs with protrusions formed at both ends. A first common mode choke coil of
A second magnetic core having the same configuration as the first magnetic core, and having protrusions at both ends opposed to the protrusions at both ends of the first magnetic core via a gap The first-phase winding and the second-phase winding are wound around the pair of magnetic legs so as to be opposite to each other and to the same-phase winding of the first common mode choke coil. A second common mode choke coil on the turned load side;
A pair of interphase capacitors provided between the power supply side terminals and between the load side terminals so as to sandwich at least one common mode choke coil in the first and second common mode choke coils;
A grounding capacitor provided between one phase of the load side terminal of the second common mode choke coil and ground;
A noise filter comprising: a grounding capacitor provided between the same side as the load side terminal and a ground at a connection point between the first common mode choke coil and the second common mode choke coil.   4. The noise filter according to claim 2, further comprising a withstand voltage adding capacitor interposed between each grounding side terminal of each grounding capacitor and the ground. In a noise filter that is provided in an electric circuit connecting a single-phase AC power source and a load-side device, and suppresses propagation of electromagnetic interference noise generated in the load-side device to the single-phase AC power source,
A power supply side in which a first phase winding and a second phase winding are wound in opposite directions on the pair of magnetic legs in the first magnetic core having a pair of magnetic legs with protrusions formed at both ends. A first common mode choke coil of
A second magnetic core having the same configuration as the first magnetic core, and having protrusions at both ends opposed to the protrusions at both ends of the first magnetic core via a gap The first-phase winding and the second-phase winding are wound around the pair of magnetic legs so as to be opposite to each other and to the same-phase winding of the first common mode choke coil. A second common mode choke coil on the turned load side;
A pair of interphase capacitors provided between the power supply side terminals and between the load side terminals so as to sandwich at least one common mode choke coil in the first and second common mode choke coils;
An interphase capacitor having one end connected to one phase of a load side terminal of the second common mode choke coil;
An interphase capacitor having one end connected to the other phase at a connection point between the first common mode choke coil and the second common mode choke coil;
A noise filter comprising: an interphase capacitor interposed between each other end of each interphase capacitor having one end connected to each phase and the ground. In a noise filter that is provided in an electric circuit connecting a single-phase AC power source and a load-side device, and suppresses propagation of electromagnetic interference noise generated in the load-side device to the single-phase AC power source,
A power supply side in which a first phase winding and a second phase winding are wound in opposite directions on the pair of magnetic legs in the first magnetic core having a pair of magnetic legs with protrusions formed at both ends. A first common mode choke coil of
A second magnetic core having the same configuration as the first magnetic core, and having protrusions at both ends opposed to the protrusions at both ends of the first magnetic core via a gap The first-phase winding and the second-phase winding are wound around the pair of magnetic legs so as to be opposite to each other and to the same-phase winding of the first common mode choke coil. A second common mode choke coil on the turned load side;
A pair of interphase capacitors provided between the power supply side terminals and between the load side terminals so as to sandwich at least one common mode choke coil in the first and second common mode choke coils;
An interphase capacitor having one end connected to one phase of a load side terminal of the second common mode choke coil;
An interphase capacitor having one end connected to the same phase as the load-side terminal at a connection point between the first common mode choke coil and the second common mode choke coil;
A noise filter comprising: a grounding capacitor interposed between each other end of each interphase capacitor having one end connected to each phase and the ground. In a noise filter that is provided in an electric circuit connecting a DC power source and a load side device, and suppresses propagation of electromagnetic interference noise generated in the load side device to the DC power source,
A power supply side in which a first phase winding and a second phase winding are wound in opposite directions on the pair of magnetic legs in the first magnetic core having a pair of magnetic legs with protrusions formed at both ends. A first common mode choke coil of
A second magnetic core having the same configuration as the first magnetic core, and having protrusions at both ends opposed to the protrusions at both ends of the first magnetic core via a gap The first-phase winding and the second-phase winding are wound around the pair of magnetic legs so as to be opposite to each other and to the same-phase winding of the first common mode choke coil. A second common mode choke coil on the turned load side;
A ferromagnetic body interposed in a gap between the first magnetic core and the second magnetic core;
A pair of interphase capacitors provided between the power supply side terminals and between the load side terminals so as to sandwich at least one common mode choke coil in the first and second common mode choke coils;
A grounding capacitor provided between one phase of the load side terminal of the second common mode choke coil and ground;
A grounding capacitor provided between one phase and a ground at a connection point between the first common mode choke coil and one second common mode choke coil, one end of which is connected to the same phase as the load side terminal. A noise filter characterized by that.

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