JP2016116306A - Power converter for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology which relates to a power converter for an electric vehicle and makes efficient electric connection between a shield plate disposed in a housing of the power converter and the housing.SOLUTION: A power converter 2 is a device used to convert electric power of a battery 3 into electric power for driving a driving motor 5. The power converter 2 includes: a power card 41 housing a switching element; a shield plate 66 for shielding high frequency noise emitted from the switching element; a sub substrate 65 including a ground pattern 65a printed thereon; and a conductive plate 67 connecting the ground pattern 65a with the housing 51. The shield plate 66 is connected with the ground pattern 65a at a position different from a connection portion between the ground pattern 65a and the conductive plate 67.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power converter for an electric vehicle.

  An electric vehicle includes a power converter that converts electric power of a DC power source into electric power for driving a traveling motor. A typical power converter is an inverter that converts direct current into alternating current. In addition to such power converters, there are also those that include a converter that boosts a DC voltage before the inverter. Inverters and converters convert power using switching elements. Moreover, an inverter and a converter are provided with the circuit board which mounted the control circuit for controlling a switching element. On the other hand, the switching element generates high frequency noise. In order to protect the elements on the circuit board from the high frequency noise of the switching element, a shield plate may be provided between the circuit board and the power card (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2006-050685

  The shield plate is preferably held at the ground potential. Further, the power converter of an electric vehicle has a housing (housing) made of metal, and the housing (housing) is fixed to a vehicle body that is held at a ground potential. That is, in the case of a power converter of an electric vehicle, the casing (housing) is held at the ground potential. Therefore, the shield plate in the power converter may be electrically connected to the housing (housing). However, it is extremely important to reduce the size of in-vehicle devices, and it may be difficult to secure a space for arranging a conductive member that conducts the shield plate and the housing (housing). The technology disclosed in the present specification relates to a power converter for an electric vehicle, and provides a technology for efficiently ensuring a conductive path for electrically connecting a shield plate to a housing (housing) within the housing of the power converter.

  The technology disclosed in the present specification makes a shield plate conductive with a housing (housing) by utilizing a member that is originally held in a power converter and held at a ground potential. The power converter disclosed in this specification includes a power card that houses a switching element, a shield plate that blocks high-frequency noise generated by the switching element, and a circuit board on which a circuit that controls the switching element is mounted. On the circuit board, an earth pattern that is held at the ground potential is printed. In order to maintain the ground pattern at the ground potential, the metal casing (housing) of the power converter and the ground pattern are connected by a conductive member. In the power converter disclosed in this specification, the shield plate is connected to the ground pattern at a position different from the connection point between the ground pattern and the conductive member. That is, the power converter disclosed in the present specification uses the ground pattern of the circuit board as a part of the conduction path between the shield plate and the housing (housing). The conductive member for electrically connecting the ground pattern of the circuit board to the housing (housing) is also an existing member. The power converter disclosed in the present specification uses an existing part for a part of the conductive path that allows the shield plate to conduct to the housing (housing), so that the internal space of the power converter can be used efficiently. Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a block diagram of the electric power system of the electric vehicle containing the power converter of an Example. It is a front view which shows the component layout in the housing of a power converter. It is a side view which shows the component layout in the housing of a power converter. It is the perspective view which looked at the capacitor unit from the slanting lower part.

  A power converter 2 according to an embodiment will be described with reference to the drawings. FIG. 1 shows a block diagram of a power system of an electric vehicle 100 including a power converter 2. The power converter 2 according to the embodiment is mounted on the electric vehicle 100. The power converter 2 boosts the voltage of the DC power of the high-voltage battery 3, converts it to AC power, and supplies it to the traveling motor 5.

  The power converter 2 includes a voltage converter 10, an inverter 20, a backup power supply circuit 30 for discharging a capacitor, and a controller 6. The voltage converter 10 boosts the voltage of the high voltage battery 3 and supplies the boosted voltage to the inverter 20. The voltage converter 10 steps down the voltage of regenerative power sent from the motor 5 via the inverter 20 and charges the high voltage battery 3. Has a step-down function. The voltage converter 10 includes two switching elements 12 and 13, a diode connected in antiparallel to each switching element, a reactor 14, and a filter capacitor 15. The two switching elements 12 and 13 are connected in series, and the series connection is connected between the positive electrode output terminal 10c and the negative electrode output terminal 10d. The reactor 14 is connected between the midpoint of the series connection of the two switching elements 12 and 13 and the positive input terminal 10a. The filter capacitor 15 is connected between the positive input terminal 10a and the negative input terminal 10b. The step-up function is mainly realized by the switching element 13, and the step-down function is mainly realized by the switching element 12. The circuit configuration of the voltage converter 10 shown in FIG. 1 is well known and will not be described in detail.

  Output terminals 10 c and 10 d of the voltage converter 10 are connected to the inverter 20. The inverter 20 includes six switching elements 21 to 26. A diode is connected in antiparallel to each switching element. Two sets of switching elements are connected in series, and three sets of series connections are provided. Three sets of series connections are connected in parallel. Three-phase alternating current is output from the midpoint of the three series connections. Since the circuit configuration of the inverter 20 is also well known, detailed description thereof is omitted. The switching elements included in the voltage converter 10 and the inverter 20 are driven by a control signal (PWM signal) supplied from the controller 6.

  A smoothing capacitor 4 is connected between the positive electrode output terminal 10c and the negative electrode output terminal 10d. The smoothing capacitor 4 is provided to suppress pulsation included in the output current of the voltage converter 10. Both the smoothing capacitor 4 and the filter capacitor 15 described above have a large capacity because the power of the high-voltage battery 3 flows, and the voltage at both ends thereof is a high voltage. The voltage converter 10 boosts, for example, a battery output voltage of 300 volts to 600 volts. The current flowing through the smoothing capacitor 4 and the filter capacitor 15 exceeds 100 amperes. When the vehicle collides, it is desirable that the large-capacity and high-voltage filter capacitor 15 and the smoothing capacitor 4 are quickly discharged. When the power converter 2 receives a signal notifying the vehicle collision from the acceleration sensor 90 included in the airbag system, the power converter 2 uses the inverter 20 and the motor 5 to discharge both capacitors 4 and 15. Specifically, unlike normal motor control, the controller 6 controls each switching element of the inverter 20 so as to output a three-phase alternating current having a phase that does not rotate the motor 5. The electric power stored in both capacitors 4 and 15 is consumed by the loss of the switching element and the loss of the motor coil.

  The controller 6 is supplied with electric power from an in-vehicle auxiliary battery (not shown). The auxiliary battery is a battery having an output voltage of 12 volts, which is also possessed by a normal gasoline vehicle. The auxiliary battery and the power converter 2 are connected by a power cable (not shown), but the power cable may be cut at the time of a collision. Alternatively, there is a possibility that the auxiliary battery is damaged during the collision and cannot supply power. When the power supply from the auxiliary battery is interrupted, the filter capacitor 15 and the smoothing capacitor 4 cannot be discharged. Therefore, the power converter 2 includes a backup power supply circuit 30 that supplies power to the controller 6 using the charged filter capacitor 15 and the smoothing capacitor 4. The backup power supply circuit 30 includes two relay switches 31 and 32, a transformer 34, a rectifier circuit 35, bridge circuits 37 and 38, and a power supply controller 33.

  The filter capacitor 15 is connected to the primary coil of the transformer 34 via the relay switch 31 and the bridge circuit 37. The smoothing capacitor 4 is also connected to another primary coil of the transformer 34 via the relay switch 32 and the bridge circuit 38. A rectifier circuit 35 is connected to the secondary side coil of the transformer 34. The output of the rectifier circuit 35 is connected to the power input terminal of the controller 6. The bridge circuit 37 is composed of a plurality of switching circuits, converts the electric power stored in the filter capacitor 15 into alternating current, and supplies the alternating current to the primary coil of the transformer 34. The bridge circuit 38 is the same as the bridge circuit 37, and converts the electric power stored in the smoothing capacitor 4 into alternating current and supplies it to another primary coil of the transformer 34. The transformer 34 receives the electric power stored in the filter capacitor 15 and the smoothing capacitor 4 and converted into an alternating current by the bridge circuits 37 and 38, and an alternating current having a voltage slightly higher than 12 volts is applied to the secondary coil. Output. The rectifier circuit 35 converts the alternating current output from the transformer 34 into direct current and supplies the controller 6 with a voltage suitable for driving the elements constituting the controller 6 (for example, TTL level 5 volts).

  A relay switch 31 is connected between the transformer 34 and the filter capacitor 15, and a relay switch 32 is connected between the transformer 34 and the smoothing capacitor 4. The relay switches 31 and 32 are both normally closed types, and are normally opened by receiving power from the power supply controller 33. That is, the backup power supply circuit 30 does not function until a collision occurs. When the controller 6 receives a signal notifying the vehicle collision from the acceleration sensor 90, it sends a backup power supply activation signal to the power supply controller 33. Upon receiving the backup power supply activation signal, the power supply controller 33 immediately stops power supply to the relay switches 31 and 32. The normally closed relay switches 31 and 32 are closed, and the filter capacitor 15 and the smoothing capacitor 4 are connected to the transformer 34. Then, electric power with an appropriate voltage is supplied to the controller 6 through the rectifier circuit 35. Therefore, the controller 6 of the power converter 2 can execute the discharge control without power supply from the auxiliary battery. The bridge circuits 37 and 38 and the power supply controller 33 are initially driven by the power supply of the auxiliary battery, but when power is output from the rectifier circuit 35, the operation is continued using the power. Therefore, even if the power supply from the auxiliary battery is interrupted during the operation of the backup power supply circuit 30, the backup power supply circuit 30 can continue the operation with the power generated by itself.

  The transformer 34 is different from other TTL level devices and receives a voltage of 100 volts or more, so that the transformer 34 is relatively large. The power converter 2 protects the transformer 34 so that the transformer 34 does not come off the substrate due to the impact of a collision. Next, the physical structure of the power converter 2 including the protection structure will be described.

  FIG. 2 shows a front view depicting a component layout in the housing of the power converter 2. FIG. 3 is a side view in the housing of the power converter 2. 2 and 3 are drawn with the side surfaces of the housing 51 cut so that the component layout can be seen. In addition, the Z-axis positive direction of the coordinate system shown in FIGS. 2 and 3 corresponds to the upper side when the power converter 2 is mounted on the vehicle. Hereinafter, the positive direction of the Z axis may be expressed as “up”, and the negative direction may be expressed as “down”.

  The switching elements included in the voltage converter 10 and the inverter 20 are collected in the stacked unit 40. The stacked unit 40 is a unit in which a plurality of flat plate-shaped cooling plates 49 and a plurality of power cards 41 are stacked. 2 and 3, the support structure for the stacked unit 40 is not shown. In FIG. 3, a part of the laminated unit 40 is not shown. Each power card 41 is sealed with two switching elements and two diodes. Within each power card 41, two switching elements are connected in series, and a diode is connected in antiparallel to each switching element. In the laminated unit 40, cooling plates 49 are arranged on both sides of each power card 41. Each cooling plate 49 is a flow path through which the refrigerant passes. Each power card 41 is cooled from both sides.

  In addition to the multilayer unit 40, a capacitor unit 60, a main board 52, and a sub board 65 are accommodated in the housing 51. In addition, a reactor, another cooler, and the like are accommodated inside the housing 51, but these are not shown.

  The capacitor unit 60 is a unit in which a plurality of capacitor elements 62 are accommodated in a resin case 61. The capacitor unit 60 is fixed to the case 61 via ribs 61 a protruding from both side surfaces of the case 61 and protrusions 53 protruding from the inner surface of the housing 51. In FIG. 2, a protrusion 53 protruding from the inner surface of the housing 51 is drawn with a broken line.

  FIG. 4 is a perspective view of the capacitor unit 60. In FIG. 4, a part of the components associated with the capacitor unit 60 is illustrated in an exploded manner. From here, it demonstrates with reference to FIG. 4 with FIG. 2, FIG. 4 is a perspective view of the capacitor unit 60 as viewed obliquely from below. Please refer to the coordinate system shown in FIGS. 2 to 4 to confirm the orientation of the capacitor unit 60 in FIG.

  A plurality of capacitor elements 62 are accommodated in the case 61. Several capacitor elements 62 constitute the smoothing capacitor 4 of FIG. 1 and the remaining capacitor elements 62 constitute the filter capacitor 15. In the figure, a plurality of capacitor elements are represented by a single reference numeral 62.

  From each power card 41, three high voltage terminals (intermediate terminal 42, negative terminal 43, and positive terminal 44) extend. The intermediate terminal 42 is connected to the midpoint of the series connection of two switching elements inside the power card 41. Hereinafter, the series connection of two switching elements is simply referred to as “series connection”. The negative electrode terminal 43 and the positive electrode terminal 44 are respectively connected to the high potential side and the low potential side of the series connection inside the power card 41. As shown in the circuit diagram of FIG. 1, the series connection included in the voltage converter 10 and the series connection included in the inverter 20 are both connected to the smoothing capacitor 4 on the high potential side and the low potential side. The negative terminal 43 of each power card 41 is connected to the capacitor element 62 via the bus bar 63. The bus bar 63 has a plurality of branches 63b extending from a base 63a of a single plate, the base 63a is connected to one terminal (not shown) of the capacitor element 62, and each branch 63b is connected to each power card. It is connected to the negative terminal 43. The positive terminal 44 of each power card 41 is connected to the capacitor element 62 via the bus bar 64. The bus bar 64 has a plurality of branches 64b extending from a base 64a of a single plate, the base 64a is connected to the other terminal (not shown) of the capacitor element 62, and each branch 64b is connected to each power card. The positive terminal 44 is connected. Refer to FIG. 4 for the shapes of the bus bars 63 and 64. However, in FIG. 4, only one branch part 63b, 64b is drawn, and the other branch parts are not shown. Further, in FIG. 4, in order to show the capacitor element 62, a part of the base portions 63a and 64a is omitted.

  A bus bar is also connected to the intermediate terminal 42, but the illustration thereof is omitted. The midpoint of the series connection included in the voltage converter 10 is connected to the filter capacitor 15. The intermediate terminal 42 of the power card that houses the switching element of the voltage converter 10 is connected to the capacitor element 62 that constitutes the filter capacitor 15 via a bus bar (not shown).

  A plurality of control terminals 45 extend from each power card 41 in addition to the three high voltage terminals. The plurality of control terminals 45 include a terminal connected to the gate electrode of the switching element and other signal terminals (for example, a current monitoring terminal). The plurality of control terminals 45 are connected to the main board 52 disposed above the stacked unit 40. The main board 52 is a board on which the controller 6 shown in FIG. 1 is mounted. In other words, the main board 52 is a board on which a circuit for controlling the switching element is mounted. Although a plurality of elements for realizing a circuit are mounted on the main board 52, these are not shown. As shown in FIG. 2, the main board 52 is fixed to a protrusion 51 a protruding from the inner surface of the housing 51 with a bolt.

  The capacitor unit 60 will be described in detail. As described above, the capacitor unit 60 is a unit in which a plurality of capacitor elements 62 are accommodated in a resin case 61. As shown in FIG. 3, the capacitor unit 60 is fixed to a protrusion 53 protruding from the inner surface of the housing 51 with a bolt. Some of the plurality of capacitor elements 62 constitute the smoothing capacitor 4 of FIG. 1, and the rest constitute the filter capacitor 15 of FIG. The capacitor element 62 is connected to a plurality of power cards 41 (that is, switching elements) by bus bars 63 and 64. Note that the bus bar that connects the middle point terminal of the power card that houses the switching element included in the voltage converter 10 and the capacitor element is not shown.

  A sub board 65 is attached to the lower side of the case 61. More specifically, several columns 61b extend downward on the lower surface of the case 61, and the sub board 65 is fixed to the tip of the column 61b with a bolt. As described above, the positive direction of the Z-axis in the figure corresponds to the upper side of the power converter 2, and the negative direction of the Z-axis corresponds to the lower side. The backup power supply circuit 30 shown in FIG. 1 is mounted on the sub board 65. 2 to 4 show the transformer 34 belonging to the backup power supply circuit 30. The transformer 34 is fixed to the sub-substrate 65, but is supported by being surrounded by a surrounding wall 61c provided on the lower surface of the housing 51, as shown in FIG. A plurality of elements (chips) for realizing the backup power supply circuit 30 are mounted on the sub-board 65, but illustration of them is omitted. The control circuit (that is, the backup power supply circuit 30) mounted on the sub board 65 is a part of a circuit for controlling the switching element.

  Since the power converter 2 is mounted in the front compartment of the vehicle, the power converter 2 is easily subjected to an impact in a forward collision. The transformer 34 is relatively larger in size than other elements mounted on the sub-board 65. Therefore, the transformer 34 may be detached from the sub-board 65 due to its inertial force when subjected to a large impact. In the capacitor unit 60, the sub board 65 is attached to the lower side of the case 61 that houses the capacitor element 62, and the transformer 34 is mounted on the side of the sub board 65 facing the case 61. Further, by providing a wall 61 c surrounding the transformer 34 on the lower surface of the case 61, the transformer 34 is prevented from being detached from the sub board 65.

  The sub board 65 and the main board 52 are electrically connected by a plurality of signal pins 68. Two of the plurality of signal pins are pins for supplying the power converted into a low voltage by the transformer 34 from the sub board 65 to the main board 52. The remaining signal pins are pins for exchanging signals between the main board 52 and the sub board 65. 2 to 4, the sub board 65 and the main board 52 are arranged separately on one side and the other side of two parallel surfaces of the case 61 of the capacitor unit 60. As shown in FIG. 4, the plurality of signal pins 68 are inserted and fixed in pin holes 65 b provided in the sub-board 65. The plurality of signal pins 68 are arranged close to the bus bars 63 and 64 that communicate with the capacitor element 62. The plurality of signal pins 68 extend in parallel with the base portions 63a and 64a of the flat bus bar. The switching elements 12, 13, 21 to 26 generate high-frequency noise (switching noise) along with the switching operation, and the high-frequency noise is absorbed by the capacitor element 62 through the bus bars 63, 64. Therefore, the high frequency noise generated by the switching elements 12, 13, 21 to 26 is also emitted from the bus bars 63, 64. The signal pins 68 run parallel to the bus bars 63 and 64 (particularly the base portions 63a and 64a). A shield plate 66 is provided to protect the signal flowing through the signal pin 68 from noise emitted by the bus bars 63 and 64. The shield plate 66 is disposed between the bus bars 63 and 64 and the signal pin 68. The shield plate 66 is made of a conductive metal plate.

  In order to effectively suppress noise, the shield plate 66 is preferably held at the ground potential. In general, the body of a vehicle is used as a reference for the ground potential. In many on-vehicle electronic devices, the housing is made of metal, and the housing is held at the ground potential by fixing the housing to the body. That is, the housing 51 of the power converter 2 is made of metal and is held at the ground potential. On the other hand, the case 61 of the capacitor unit 60 is made of resin as an insulator. The power converter 2 uses the ground pattern 65 a of the sub-board 65 in order to make the shield plate 66 conductive with the housing 51. The earth pattern 65a is a printed wiring that is held at a ground potential among various wirings printed on the sub-board 65. The ground pattern 65 a itself needs to be electrically connected to the housing 51. In the power converter 2 of the embodiment, the ground pattern 65a is used to hold the shield plate 66 at the ground potential, and the wiring of the conductive member for electrically connecting the shield plate 66 and the housing 51 is shortened. And simplified.

  The shield plate 66 is electrically connected to the housing 51 by the ground pattern 65 a of the sub-board 65 and the conductive plate 67. 2 and 3, the shield plate 66, the ground pattern 65a, and the conductive plate 67 are shown in gray so that they can be easily understood. A joint plate 66a extends from the edge of the shield plate 66, and the joint plate 66a is in contact with one end 65a1 of the ground pattern 65a. In FIG. 4, the ground pattern 65 a is provided on the surface of the sub-substrate 65 facing the positive direction of the Z axis, and therefore the ground pattern 65 a is represented by a broken line. A through hole is received at one end 65a1 of the ground pattern 65a, and the sub-board 65 and the joint plate 66a are fastened together with a bolt (not shown) passing through the through hole and the column 61b. By fastening together, electrical connection between the ground pattern 65a and the joint plate 66a (that is, the shield plate 66) is secured.

  The other end 65a2 of the ground pattern 65a is also provided with a through hole, and the other end 65a2 of the ground pattern 65a and the conductive plate 67 are fastened together with a bolt (not shown) passing through the through hole and another support 61b. That is, the conductive plate 67 is in contact with the other end 65a2 of the ground pattern 65a. The conductive plate 67 is connected to the ground pattern 65a at a position (that is, the other end 65a2 of the ground pattern 65a) that is different from the connection location of the ground pattern 65a to the shield plate 66 (that is, one end 65a2 of the ground pattern 65a). By fastening together, conduction between the ground pattern 65a and the conductive plate 67 is ensured. The other end of the conductive plate 67 reaches the rib 61 a of the case 61. The case 61 is fixed to a protrusion 53 protruding from the inner surface of the housing 51 with a bolt passing through the rib 61a. The other end of the conductive plate 67 is sandwiched between the rib 61 a of the case 61 and the protrusion 53 of the housing 51. By this clamping, electrical conduction between the conductive plate 67 and the housing 51 is ensured. The conductive plate 67 is a member provided to hold the ground pattern 65 a at the ground potential of the housing 51, and is originally provided inside the housing 51 regardless of the presence or absence of the shield plate 66. It is a member.

  In the power converter 2, the shield plate 66 and the housing 51 are not directly connected by the conductive plate to ensure conduction, but the conduction between the two is secured by using the ground pattern 65a of the sub-board 65 and the conductive plate 67. Thereby, the conduction path between the shield plate 66 and the housing 51 is simplified. This technique is effective when a space for arranging the conductive plate cannot be secured between the shield plate 66 and the housing 51.

  Points to be noted regarding the technology described in the embodiments will be described. The signal pins 68 and the shield plate 66 are preferably molded into one part by molding with resin. This is because the shield plate 66 can be assembled simultaneously with the assembly of the signal pin 68 to the capacitor unit 60.

  In the power converter 2 of the embodiment, the backup power supply circuit 30 is always operated when the vehicle collides. You may make it start a backup power supply circuit, when the power converter 2 cannot receive the electric power feeding from an auxiliary machine battery at the time of a vehicle collision.

  In the embodiment, the power converter 2 is mounted on the electric vehicle 100. The technology disclosed in this specification can also be applied to hybrid vehicles and fuel cell vehicles. The power converter 2 of the embodiment discharges the filter capacitor 15 and the smoothing capacitor 4 using the inverter 20 and the motor 5. The inverter 20 and the motor 5 are an example of a discharge circuit. The sub-board 65 is an example of a circuit board on which a circuit for controlling a switching element is mounted and an earth pattern that is held at a ground potential is printed.

  The characteristics of the power converter 2 are listed as follows. The power converter 2 is a device that converts the power of the battery 3 (DC power supply) into power for driving the traveling motor 5. The power converter 2 includes a power card 41, a capacitor element 62, and bus bars 63 and 64. The power card 41 contains a switching element. Capacitor element 62 smoothes the current passing through the switching element of power card 41. The bus bars 63 and 64 electrically connect the power card 41 and the capacitor element 62. As for the bus bars 63 and 64, the base parts 63a and 64a are flat plate types. The power converter 2 includes a main board 52 (first board) on which a part of a circuit for controlling the switching element is mounted, and a sub board on which another part of the circuit for controlling the switching element is mounted. 65 (second substrate) is further provided. On the sub-substrate 65, an earth pattern 65a held at the ground potential is printed. The main board 52 and the sub board 65 are electrically connected by signal pins 68 extending in parallel with the bus bar. The signal pin 68 extends in parallel with the bus bars 63 and 64 (particularly, the base portions 63a and 64a). Between the bus bars 63 and 64 (particularly, the bases 63a and 64a thereof) and the signal pins 68, a shield plate 66 that protects signals flowing through the signal pins from high frequency noise generated by the bus bars is disposed. The ground pattern 65 a of the sub-board 65 is electrically connected to the housing 51 and the conductive plate 67. The shield plate 66 is connected to the ground pattern 65a at a position (65a1) different from the connection location (65a2) of the sub-board 65 to the ground pattern 65a.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Power converter 3: High voltage battery 4: Smoothing capacitor 5: Motor 6: Controller 10: Voltage converters 12, 13, 21-26: Switching element 14: Reactor 15: Filter capacitor 20: Inverter 30: Backup power supply circuit 31, 32: Relay switch 33: Power supply controller 34: Transformer 35: Rectifier circuit 37, 38: Bridge circuit 40: Laminating unit 41: Power card 42: Intermediate terminal 43: Negative terminal 44: Positive terminal 45: Control terminal 49: Cooling Plate 51: Housing 51a, 53: Protrusion 52: Main board 60: Capacitor unit 61: Case 61c: Enclosure wall 62: Capacitor element 63, 64: Bus bar 63a, 64a: Base 63b, 64b: Branch 65: Sub board 65a: Earth pattern 66: shield plate 66a Joint plate 67: conductive plate 68: signal pin 100: electric car

Claims (1)

It is a power converter that converts the power of the DC power source into power for driving the traveling motor,
A power card containing a switching element;
A shield plate that blocks high-frequency noise generated by the switching element;
A circuit board on which a circuit for controlling the switching element is mounted, and a circuit board printed with an earth pattern held at a ground potential;
A conductive member connected to the ground pattern of the circuit board and a metal housing of the power converter;
With
The power converter, wherein the shield plate is connected to the ground pattern at a position different from a connection place between the ground pattern and the conductive member.