JP2019004634A - Electric power conversion system - Google Patents

Abstract

To reduce conduction noise.SOLUTION: An electric power conversion system 10 comprises a case 50 made of metal, a filter substrate 60, and a power substrate 70. The filter substrate 60 composes an AC filter and a DC filter. The power substrate 70 composes a DC/DC converter. The filter substrate 60 is disposed parallel to the internal surface of the case 50 closest to the filter substrate 60. The power substrate 70 is disposed perpendicular to both the filter substrate 60 and the internal surface of the case 50 closest to the power substrate 70.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power conversion device.

  A power conversion device that performs power conversion by switching operation of a switching element includes a grounded case and a substrate on which the switching element is provided. Due to the switching operation of the switching element, conduction noise is generated in the power converter. The conduction noise changes depending on the voltage fluctuation at the time of switching and the magnitude of the stray capacitance generated between the substrate and the case. In order to reduce conduction noise, in the power converter disclosed in Patent Literature 1, conduction noise is reduced by intentionally generating stray capacitance at a position where conduction noise can be reduced by the capacitance forming member.

Japanese Patent Laying-Open No. 2015-106601

  By the way, when the power converter is miniaturized, the distance between the substrate and the case is shortened, and the stray capacitance generated between the substrate and the case is increased. As this stray capacitance increases, conduction noise increases.

  The objective of this invention is providing the power converter device which can reduce conduction noise.

  A power converter that solves the above problems includes an AC filter that reduces noise included in AC power supplied from an AC power supply, a DC / DC converter that performs voltage conversion, and a DC that is voltage-converted by the DC / DC converter. A power conversion device comprising: a DC filter that reduces noise included in a voltage; and the AC filter, the DC / DC converter, and a case in which the DC filter is accommodated and grounded. And a filter board that constitutes the DC filter, a power board that constitutes the DC / DC converter, a filter board, and a connector that electrically connects the power board, the filter board comprising: Arranged parallel to the inner surface of the case closest to the filter substrate. Nearest the inner surface of the case over the substrate, and are arranged perpendicular to both of the filter substrate.

  When the stray capacitance between the power board constituting the DC / DC converter and the inner surface of the case is large, the conduction noise becomes large. Since the stray capacitance increases according to the facing area between the power board and the inner surface of the case, the power board is arranged perpendicular to the inner surface of the case closest to the power board, so that the power board and the inner surface of the case Conductive noise can be reduced by reducing stray capacitance generated between the two.

  In the power conversion apparatus, the DC / DC converter includes a transformer, a primary side circuit of the transformer, and a secondary side circuit of the transformer, and the power board is a negative wiring of the primary side circuit. A primary side negative electrode pattern and a secondary side negative electrode pattern which constitutes a negative electrode wiring of the secondary side circuit, and the primary side negative electrode pattern and the secondary side negative electrode pattern are opposed to each other. It may be arranged.

  According to this, since a primary side negative electrode pattern and a secondary side negative electrode pattern are arrange | positioned facing, electrostatic capacitance arises between both. Thereby, it can be considered that the primary side circuit and the secondary side circuit of the transformer are connected by a bypass capacitor having two negative electrode patterns as electrode plates. By diverting the current (conductive noise) flowing to the ground to the bypass capacitor, the conductive noise can be reduced.

  In the power conversion device, the primary negative electrode pattern and the secondary negative electrode pattern are disposed in a plane in the thickness direction of the power board, the furthest away from the inner surface of the case closest to the power board. It may be.

  According to this, the stray capacitance generated between each negative electrode pattern and the inner surface of the case can be reduced, and the conduction noise can be further reduced.

  According to the present invention, conduction noise can be reduced.

The circuit diagram of the power converter in an embodiment. Sectional drawing which shows schematically the power converter device in embodiment.

Hereinafter, an embodiment of the power conversion device will be described. The power converter of this embodiment is mounted on a vehicle.
As shown in FIG. 1, the vehicle includes a power conversion device 10 and a battery B. The vehicle is an electric vehicle using an electric motor as a drive source or a hybrid vehicle. The battery B is a chargeable / dischargeable power storage device and is used as a power source of an electric motor mounted on a vehicle.

  The power conversion device 10 includes an input end 12 to which an AC power supply 11 is connected. The AC power supply 11 is a system power supply used in a general home. Although not shown, the AC power supply 11 is connected to the input terminal 12 using a home charging facility installed in the home. The power conversion device 10 is used as an in-vehicle charger that charges the battery B by converting AC power input from the AC power source 11 into DC power and outputting the DC power.

  As shown in FIG. 1, the power conversion device 10 includes an AC filter (AC filter) 20, a PFC (power factor correction circuit) 25, a DC / DC converter 30, and a DC filter (DC filter) 40. .

  The AC filter 20 is provided between the AC power supply 11 connected to the input terminal 12 and the PFC 25, and reduces noise included in the AC power input from the AC power supply 11. In addition, the AC filter 20 reduces conduction noise generated in the power conversion device 10, thereby suppressing conduction noise from flowing into the AC power supply 11.

  The AC filter 20 includes three X capacitors (across the line capacitors) CX, two common choke coils 21 and 22, and four Y capacitors (line bypass capacitors) CY1. The AC filter 20 is a two-stage filter including two common choke coils 21 and 22.

  Both the common choke coils 21 and 22 each include two windings L1 and L2 wound around a single core. The winding directions of both windings L1, L2 are opposite to each other. The windings L1 of the two common choke coils 21 and 22 are connected in series, and the windings L2 are connected in series.

  The X capacitor CX is provided between the input terminal 12 and the common choke coil 21, between the common choke coils 21 and 22, and between the common choke coil 22 and the PFC 25, respectively.

  The two Y capacitors CY1 are connected in series to form a series circuit of the Y capacitors CY1. By providing two series circuits of Y capacitors CY1, the AC filter 20 includes a total of four Y capacitors CY1. The series circuit of the Y capacitor CY1 is provided between the common choke coils 21 and 22 and between the common choke coils 21 and 22 and the PFC 25, respectively. The X capacitor CX and the series circuit of the Y capacitor CY1 are connected in parallel. The midpoint between the Y capacitors CY1 connected in series is grounded (grounded) to the vehicle body.

  In the AC filter 20 described above, common mode noise is reduced by the windings L1 and L2 and the Y capacitor CY1, and normal mode noise is reduced by the leakage inductance of the common choke coils 21 and 22 and the X capacitor CX.

The PFC 25 is provided between the AC filter 20 and the DC / DC converter 30, converts an AC voltage into a DC voltage and outputs the DC voltage to the DC / DC converter 30 while improving the power factor.
The PFC 25 includes a coil L3, a conversion unit 26, and a control mechanism 27. The conversion unit 26 includes two diodes D1 and D2, two switching elements Q1 and Q2, and one smoothing capacitor C1.

  MOSFETs are used as the switching elements Q1 and Q2. Each switching element Q1, Q2 constitutes a series circuit of switching elements Q1, Q2 by being connected in series with each other. Specifically, the drain of the switching element Q2 is connected to the source of the switching element Q1.

  The diodes D1 and D2 are connected in series to form a series circuit of the diodes D1 and D2. Specifically, the cathode of the diode D2 is connected to the anode of the diode D1.

  The drain of the switching element Q1 and the cathode of the diode D1 are connected to the first positive line L11. The source of the switching element Q2 and the anode of the diode D2 are connected to the first negative line L12. Thereby, the series circuit of the switching elements Q1 and Q2 and the series circuit of the diodes D1 and D2 are connected in parallel.

  An output end of the AC filter 20 is connected to a midpoint between the switching element Q1 and the switching element Q2 (a connection portion that connects the switching elements Q1 and Q2) via a coil L3. The output end of the AC filter 20 is connected to a midpoint between the diode D1 and the diode D2 (a connection portion that connects the diodes D1 and D2).

One end of the smoothing capacitor C1 is connected to the first positive electrode wiring L11, and the other end of the smoothing capacitor C1 is connected to the first negative electrode wiring L12.
The control mechanism 27 includes a driver unit 28 and a control unit 29. The driver unit 28 is connected to the gates of the switching elements Q1 and Q2. The driver unit 28 controls on / off of the switching elements Q1, Q2 based on a signal from the control unit 29. Then, when the switching elements Q1 and Q2 are switched (on / off operation), a DC voltage is supplied to the DC / DC converter 30 via the first positive electrode wiring L11 and the first negative electrode wiring L12.

The DC / DC converter 30 is an insulated DC / DC converter provided between the PFC 25 and the DC filter 40.
The DC / DC converter 30 includes one bridge circuit 31, two diodes D3 and D4, two coils L4 and L5, one transformer 32, one rectifier circuit 35, one smoothing capacitor C2, And a control mechanism 36.

  The bridge circuit 31 provided on the primary side of the transformer 32 includes four switching elements Q3, Q4, Q5, and Q6. MOSFETs are used as the switching elements Q3, Q4, Q5, and Q6. Switching element Q3 and switching element Q4 are connected in series to form a series circuit of switching elements Q3 and Q4. Specifically, the drain of the switching element Q4 is connected to the source of the switching element Q3. Similarly, switching element Q5 and switching element Q6 are connected in series.

  The diodes D3 and D4 provided on the primary side of the transformer 32 are connected in series to form a series circuit of the diodes D3 and D4. Specifically, the cathode of the diode D4 is connected to the anode of the diode D3.

  The drains of the switching elements Q3 and Q5 are connected to the first positive electrode wiring L11. The sources of the switching elements Q4 and Q6 are connected to the first negative line L12. The cathode of the diode D3 is connected to the first positive line L11. The anode of the diode D4 is connected to the first negative line L12. Thereby, the series circuit of switching element Q3 and switching element Q4, the series circuit of switching element Q5 and switching element Q6, and the series circuit of diodes D3 and D4 are connected in parallel.

  The bridge circuit 31, the diodes D3 and D4, the first positive electrode wiring L11, and the first negative electrode wiring L12 serve as a primary circuit E1 provided on the primary side of the transformer 32. In the present embodiment, the first positive electrode wiring L11 and the first negative electrode wiring L12 are also part of the PFC 25. Therefore, it can be said that the PFC 25 and the primary circuit E1 include the common first positive electrode wiring L11 and the first negative electrode wiring L12. The first positive electrode wiring L11 and the first negative electrode wiring L12 are wirings for inputting a DC voltage to the DC / DC converter 30 (primary side circuit E1). A primary side voltage, that is, a DC voltage before voltage conversion by the DC / DC converter 30 is applied to the first positive electrode wiring L11 and the first negative electrode wiring L12.

  The transformer 32 includes a primary side winding 33 and a secondary side winding 34. One end of the primary winding 33 is connected to the midpoint between the switching elements Q3 and Q4 via the coil L4, and the other end of the primary winding 33 is the midpoint between the switching elements Q5 and Q6. It is connected to the.

  The rectifier circuit 35 provided on the secondary side of the transformer 32 includes four diodes D5, D6, D7, and D8. The diode D5 and the diode D6 are connected in series to form a series circuit of the diodes D5 and D6. Specifically, the cathode of the diode D6 is connected to the anode of the diode D5. Similarly, the diode D7 and the diode D8 are connected in series with each other. The cathodes of the diodes D5 and D7 are connected to the second positive electrode wiring L21. The anodes of the diodes D6 and D8 are connected to the second negative line L22. Thereby, the series circuit of the diodes D5 and D6 and the series circuit of the diodes D7 and D8 are connected in parallel.

One end of the secondary winding 34 is connected to the midpoint of the diodes D5 and D6, and the other end of the secondary winding 34 is connected to the midpoint of the diodes D7 and D8.
The coil L5 is provided as a part of the second positive electrode wiring L21. One end of the smoothing capacitor C2 is connected to the second positive electrode wiring L21, and the other end of the smoothing capacitor C2 is connected to the second negative electrode wiring L22. The rectifier circuit 35, the smoothing capacitor C2, the second positive electrode wiring L21, and the second negative electrode wiring L22 form a secondary circuit E2 provided on the secondary side of the transformer 32.

  The control mechanism 36 includes a driver unit 37 and a control unit 38. Driver unit 37 is connected to the gates of switching elements Q3, Q4, Q5, and Q6. The driver unit 37 controls on / off of the switching elements Q3, Q4, Q5, and Q6 based on a signal from the control unit 38. Then, due to the switching operation of the switching elements Q3, Q4, Q5, and Q6, the DC voltage input from the first positive electrode wiring L11 and the first negative electrode wiring L12 varies depending on the state of charge of the battery B, etc. It is converted into a DC voltage (voltage conversion is performed). Then, the DC voltage after voltage conversion is output from the second positive electrode wiring L21 and the second negative electrode wiring L22. The second positive line L21 and the second negative line L22 are lines that output a DC voltage from the DC / DC converter 30 (secondary circuit E2). A secondary side voltage, that is, a DC voltage after voltage conversion by the DC / DC converter 30 is applied to the second positive line L21 and the second negative line L22.

  In the present embodiment, the second positive electrode wiring L21 and the second negative electrode wiring L22 are also part of the DC filter 40. Therefore, it can be said that the DC filter 40 and the secondary side circuit E2 include the common second positive electrode wiring L21 and the second negative electrode wiring L22.

  The DC filter 40 includes one common choke coil 41 and four Y capacitors CY2. The common choke coil 41 has the same configuration as the common choke coils 21 and 22 described above, and includes two windings L6 and L7. The two Y capacitors CY2 are connected in series to form a series circuit of Y capacitors CY2. By providing two series circuits of Y capacitors CY2, the DC filter 40 includes a total of four Y capacitors CY2. The midpoint between the Y capacitors CY2 connected in series is grounded (grounded) to the vehicle body. The DC filter 40 reduces noise included in the DC voltage.

  As shown in FIG. 2, the power conversion device 10 includes a metal case 50, a filter substrate 60, a power substrate 70, and a connector 61 that electrically connects the filter substrate 60 and the power substrate 70. . In addition, in FIG. 2, the arrangement position of each member is shown typically.

  The case 50 is grounded (grounded) to the vehicle body. The case 50 includes a bottomed cylindrical main body 51 and a lid 52 that closes the main body 51. The main body 51 of the present embodiment has a bottomed rectangular tube shape, and includes a rectangular bottom portion 53 and four rectangular side walls 54.

  The filter substrate 60 constitutes a part of the AC filter 20 and a part of the DC filter 40. The filter substrate 60 includes an insulating layer 62 and a conductor pattern (not shown) provided on the insulating layer 62. And each passive element (each winding L1, L2, L6, L7, each X capacitor CX, and each Y capacitor CY1, CY2) constituting the AC filter 20 and the DC filter 40 is connected by a conductor pattern. Thus, the AC filter 20 and the DC filter 40 are configured.

  The filter substrate 60 is fixed to the bottom 53 of the case 50 through, for example, a spacer (not shown). The filter substrate 60 is disposed so that the surface in the thickness direction faces the inner surface of the bottom portion 53, in other words, parallel to the inner surface of the bottom portion 53. That is, the filter substrate 60 is disposed so that the thickness direction of the filter substrate 60 is orthogonal to the inner surface of the bottom portion 53. Here, “parallel” means that a slight inclination of the filter substrate 60 is allowed.

  In the present embodiment, the inner surface of the case 50 closest to the filter substrate 60 is the inner surface of the bottom portion 53. More specifically, when the distances from the surface in the thickness direction of the filter substrate 60 and the side surface (surface in the direction orthogonal to the thickness direction) of the filter substrate 60 to the inner surface of the case 50 facing each surface are compared. The distance d1 from the surface in the thickness direction of the filter substrate 60 to the inner surface of the bottom 53 is the shortest.

  The connector 61 is provided on the surface of the filter substrate 60 opposite to the surface facing the bottom portion 53. The conductor pattern provided on the filter substrate 60 and the conductor pattern provided on the power substrate 70 are connected via a connector 61 (specifically, a conductor of the connector).

  The power board 70 forms part of the PFC 25 and the DC / DC converter 30. The power substrate 70 includes an insulating layer 73 and a conductor pattern provided on the insulating layer 73. In FIG. 2, the primary negative electrode pattern 71 constituting the first negative electrode wiring L12 that is the negative electrode wiring of the primary side circuit E1 and the second negative electrode that is the negative electrode wiring of the secondary circuit E2 in the conductor pattern. Only the secondary-side negative electrode pattern 72 constituting the wiring L22 is illustrated. The PFC 25 and the DC / DC converter 30 are configured by connecting the members constituting the PFC 25 and the DC / DC converter 30 with the conductor pattern.

  The power substrate 70 is disposed so as to be perpendicular to the filter substrate 60. A side surface (surface in a direction orthogonal to the thickness direction of the power substrate 70) A of the power substrate 70 faces the filter substrate 60. Here, “vertical” means that a slight inclination of the power substrate 70 is allowed. Since the filter substrate 60 and the inner surface of the bottom portion 53 are parallel to each other, the power substrate 70 is disposed perpendicular to the inner surface of the bottom portion 53 by providing the power substrate 70 perpendicular to the filter substrate 60. The That is, the power substrate 70 is disposed perpendicular to both the filter substrate 60 and the inner surface of the bottom 53.

  Of the inner surfaces of the case 50, the surface closest to the power board 70 is the inner surface of the bottom portion 53. Specifically, when comparing the distance from the surface in the thickness direction of the power substrate 70 and the side surface (surface in the direction orthogonal to the thickness direction) of the power substrate 70 to the inner surface of the case 50 facing each surface. The distance d2 from the side surface A of the power substrate 70 to the inner surface of the bottom 53 is the shortest. Therefore, the inner surfaces of the case 50 closest to the filter substrate 60 and the power substrate 70 are both inner surfaces of the bottom portion 53. It can be said that the filter substrate 60 and the power substrate 70 are disposed sufficiently apart from the inner surface of the side wall 54 and the inner surface of the lid 52.

  The control mechanism 27 of the PFC 25 and the control mechanism 36 of the DC / DC converter 30 are provided near the filter substrate 60 in the power substrate 70. The two control mechanisms 27 and 36 face each other in the thickness direction of the power board 70. The coil L3 is provided at the same position as the control mechanism 27 of the PFC 25, and the coil L5 and the smoothing capacitor C2 are provided at the same position as the control mechanism 36 of the DC / DC converter 30.

  The conversion unit 26 of the PFC 25 and the primary side circuit E1 of the DC / DC converter 30 are provided on the power substrate 70 in the thickness direction of the filter substrate 60 so as to be separated from the filter substrate 60 by the control mechanism 27. In the following description, the conversion unit 26 of the PFC 25 and the primary circuit E1 of the DC / DC converter 30 are referred to as a primary unit U.

  The secondary side circuit E <b> 2 of the DC / DC converter 30 is provided on the power board 70 in the thickness direction of the filter board 60 so as to be separated from the filter board 60 than the control mechanism 36. The primary side unit U and the secondary side circuit E <b> 2 are arranged to face each other in the thickness direction of the power board 70.

The transformer 32 is disposed to face the side surface of the power board 70. That is, the transformer 32 is disposed out of the thickness direction of the power substrate 70.
The primary-side negative electrode pattern 71 and the secondary-side negative electrode pattern 72 are disposed to face each other in the thickness direction of the power substrate 70 with the insulating layer 73 interposed therebetween. More specifically, when the power substrate 70 is a double-sided substrate, the primary negative electrode pattern 71 and the secondary negative electrode pattern 72 are provided on both surfaces of the insulating layer 73. When the power substrate 70 is a multilayer substrate, the primary negative electrode pattern 71 and the secondary negative electrode pattern 72 are provided in different layers.

  Both the negative electrode patterns 71 and 72 are disposed at a position farthest from the filter substrate 60 in the plane in the thickness direction of the power substrate 70. The negative electrode patterns 71 and 72 are also farthest away from the inner surface of the bottom portion 53 in the plane of the power substrate 70 in the thickness direction.

  The negative electrode patterns 71 and 72 are so-called solid patterns and have a larger area than the patterns used in the control mechanisms 27 and 36 which are small-signal devices. By arranging the control mechanisms 27 and 36 close to the filter substrate 60, both the negative electrode patterns 71 and 72 can be arranged apart from the filter substrate 60.

Next, the effect | action of the power converter device 10 of this embodiment is demonstrated.
When charging the battery B, the switching elements Q1, Q2, Q3, Q4, Q5, and Q6 are switched to charge the battery B. At this time, conduction noise is generated by the switching operation.

  The magnitude of the conduction noise can be expressed by C · dv / dt. C is a stray capacitance generated between the negative electrode patterns 71 and 72 of the power substrate 70 and the inner surface of the bottom 53, v is a voltage, and t is time. As the stray capacitance C increases, the conduction noise caused by the voltage fluctuation dv / dt accompanying the switching operation increases.

  The stray capacitance increases as the facing area between the negative electrode patterns 71 and 72 of the power substrate 70 and the inner surface of the bottom 53 increases. By disposing the power substrate 70 perpendicularly to the inner surface of the bottom portion 53, compared to the case where the power substrate 70 is disposed parallel to the inner surface of the bottom portion 53, the opposing area between the power substrate 70 and the inner surface of the bottom portion 53 Becomes smaller. Thereby, stray capacitance generated between the negative electrode patterns 71 and 72 and the inner surface of the bottom 53 is reduced.

  Furthermore, the primary negative electrode pattern 71 and the secondary negative electrode pattern 72 are arranged to face each other, so that the two negative electrode patterns 71 and 72 function as electrode plates forming a capacitor. Capacitance is generated between them. Then, as shown in FIG. 1, it can be considered that the primary side circuit E1 of the transformer 32 and the secondary side circuit E2 of the transformer 32 are connected via the bypass capacitor CB. As a result, the current (noise) flowing to the ground can be shunted to the bypass capacitor CB, and noise can be prevented from flowing to the ground. Thereby, conduction noise can be reduced.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) By disposing the power substrate 70 perpendicularly to the inner surface of the bottom portion 53, the stray capacitance generated between the power substrate 70 and the inner surface of the bottom portion 53 is reduced. Thereby, conduction noise caused by stray capacitance is reduced. When conduction noise enters the AC power supply 11, it may affect other devices (for example, home appliances) connected to the AC power supply 11. By reducing the conduction noise, it is possible to suppress the conduction noise from entering the AC power supply 11 and to suppress the influence on other devices connected to the AC power supply 11.

  (2) By arranging the negative electrode patterns 71 and 72 so as to face each other, the negative electrode patterns 71 and 72 are used as electrode plates for forming the bypass capacitor CB. That is, the negative electrode patterns 71 and 72 can be used as the electrode plates of the bypass capacitor CB. Thereby, conduction noise can be reduced without adding a dedicated bypass capacitor for connecting the primary side circuit E1 of the transformer 32 and the secondary side circuit E2 of the transformer 32.

  (3) The negative electrode patterns 71, 72 are arranged farthest from the filter substrate 60 in the plane of the power substrate 70 in the thickness direction. Thereby, compared with the case where each negative electrode pattern 71 and 72 is arrange | positioned close to the filter board | substrate 60, each negative electrode pattern 71 and 72 and the inner surface of the bottom part 53 will be spaced apart. The stray capacitance generated between the power substrate 70 and the inner surface of the bottom 53 increases as the distance between each negative electrode pattern 71 and 72 and the inner surface of the bottom 53 decreases. Therefore, the stray capacitance generated between the power substrate 70 and the inner surface of the bottom 53 can be reduced as compared with the case where the negative electrode patterns 71 and 72 are arranged close to the filter substrate 60, and the conduction noise is reduced. be able to.

  (4) The parasitic inductance generated between the midpoint of the Y capacitors CY1 and CY2 connected in series and the ground causes deterioration of the filter attenuation characteristic. The parasitic inductance can be reduced by bringing the AC filter 20 and the DC filter 40 close to the inner surface of the case 50. By disposing the filter substrate 60 closer to the bottom 53 of the case 50 than the power substrate 70, the parasitic inductance can be reduced and the filter characteristics can be improved.

In addition, you may change embodiment as follows.
Each negative electrode pattern 71, 72 may be provided at a position different from the position farthest from the filter substrate 60. For example, the negative electrode patterns 71 and 72 may be disposed close to the filter substrate 60.

The negative electrode patterns 71 and 72 may be arranged at positions that do not face each other.
The arrangement position of each member constituting the DC / DC converter 30 shown in FIG. 2 may be changed as appropriate.

The configuration of the AC filter 20, the PFC 25, the DC / DC converter 30, and the DC filter 40 may be changed as appropriate.
As the switching elements Q1, Q2, Q3, Q4, Q5, and Q6, switching elements other than MOSFETs such as IGBT (Insulated Gate Bipolar Transistor) may be used.

  The inner surface of the case 50 closest to each substrate may be different between the filter substrate 60 and the power substrate 70.

  E1 ... Primary side circuit, E2 ... Secondary side circuit, L12 ... First negative electrode wiring, L22 ... Second negative electrode wiring, 10 ... Power converter, 11 ... AC power supply, 20 ... AC filter, 30 ... DC / DC converter , 50 ... Case, 60 ... Filter substrate, 61 ... Connector, 70 ... Power substrate, 71 ... Primary negative electrode pattern, 72 ... Secondary negative electrode pattern.

Claims (3)

An AC filter that reduces noise included in AC power supplied from an AC power source;
A DC / DC converter that performs voltage conversion;
A DC filter for reducing noise included in the DC voltage converted by the DC / DC converter;
A power converter including the AC filter, the DC / DC converter, and a case in which the DC filter is accommodated and grounded,
A filter substrate constituting the AC filter and the DC filter;
A power board constituting the DC / DC converter;
A connector for electrically connecting the filter substrate and the power substrate;
The filter substrate is disposed in parallel to the inner surface of the case closest to the filter substrate;
The power converter, wherein the power board is disposed perpendicular to both the inner surface of the case closest to the power board and the filter board. The DC / DC converter is
With a transformer,
A primary side circuit of the transformer;
A secondary side circuit of the transformer,
The power board is
A primary negative electrode pattern constituting the negative electrode wiring of the primary circuit;
A secondary side negative electrode pattern constituting a negative electrode wiring of the secondary side circuit,
The power converter according to claim 1, wherein the primary negative electrode pattern and the secondary negative electrode pattern are arranged to face each other.   The said primary side negative electrode pattern and the said secondary side negative electrode pattern are arrange | positioned most spaced apart from the inner surface of the said case nearest to the said power board in the surface of the thickness direction of the said power board. The power converter described.