JP2010016941A - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power converter which can suppress common mode noise in a simple configuration. <P>SOLUTION: A motor controller 1 includes a power converter circuit 11 composed of IGBTs (high-potential side switching elements) 110 to 115 and capacitors C1 to C12. The capacitors C1 to C12 are constituted of the electrodes of the IGBTs 110 to 115, a cooler and an insulating member. One ends of the capacitors C1 to C12 are connected to the collector terminals and the emitter terminals of the IGBTs 110 to 115. The other ends of the capacitors C1, C4, C5, C8, C9, C12 are connected to each other. The other ends of the capacitors C2, C3, C6, C7, C10, C11 are connected to each other and are grounded on a vehicle body. Thereby part of noises generated at the IGBTs 110 to 115 can be prevented from being bypassed to the vehicle body to suppress the amount of noises bypassed to the vehicle body lower than ever before. Thus the common mode noise can be suppressed in spite of the simple configuration of the power converter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power conversion device including a high potential side switching element and a low potential side switching element. In particular, the present invention relates to a power conversion device in which a high potential side switching element and a low potential side switching element are held by a holding member having conductivity via an insulating member.

  Conventionally, there is an inverter device for a hybrid vehicle disclosed in Patent Document 1, for example, as a power conversion device including a high potential side switching element and a low potential side switching element.

  The inverter device includes a semiconductor module, a first insulating member and a second insulating member, and an upper holding tube and a lower holding tube. The semiconductor module is composed of an IGBT and a flywheel diode, and is integrally formed into a flat rectangular shape with a module resin. The first electrode plate is exposed on the surface side of the semiconductor module. Further, the second electrode plate is exposed on the back side of the semiconductor module. The first insulating member and the second insulating member are in close contact with the first electrode plate and the second electrode plate of the semiconductor module, respectively. The upper holding tube and the lower holding tube are in close contact with the first insulating member and the second insulating member, respectively, and hold the semiconductor module. The upper holding pipe and the lower holding pipe are both grounded to the vehicle body.

Thereby, a bypass capacitor is comprised by an electrode plate, a holding tube, and an insulating member. Therefore, all noise is bypassed to the vehicle body by the bypass capacitor, and normal mode noise can be suppressed.
JP 2005-73342 A

Incidentally, in vehicles such as hybrid vehicles, various electronic devices are mounted in addition to the inverter device. These electronic devices are operated by a power supply voltage based on the vehicle body. However, although the above-described inverter device can suppress normal mode noise, it bypasses the noise to the vehicle body, and conversely increases common mode noise. Therefore, common mode noise is superimposed on the power supply voltage, which may affect the operation of other electronic devices.

  This invention is made | formed in view of such a situation, and it aims at providing the power converter device which can suppress common mode noise with a simple structure.

Means for Solving the Problems and Effects of the Invention

  Therefore, as a result of extensive research and trial and error to solve this problem, the present inventor grounded a predetermined capacitor among capacitors composed of an electrode, a holding member, and an insulating member, and other capacitors. As a result, it was conceived that common mode noise can be suppressed with a simple configuration by electrically connecting the two, and the present invention has been completed.

  That is, the power conversion device according to claim 1 includes a high potential side switching element having a high potential side electrode and a low potential side electrode, a high potential side electrode and a low potential side electrode, and the high potential side electrode is high. A low potential side switching element electrically connected to a low potential side electrode of the potential side switching element, and a first insulation disposed in contact with the high potential side electrode and the low potential side electrode of the high potential side switching element, respectively. A third insulating member and a fourth insulating member disposed in contact with the high potential side electrode and the low potential side electrode of the low potential side switching element, and the high potential side switching element, respectively. A conductive first holding member that is disposed in contact with the first insulating member and the second insulating member in a state of facing the potential side electrode and the low potential side electrode, respectively, and holds the high potential side switching element. The second holding member and the third insulating member and the fourth insulating member in contact with the high potential side electrode and the low potential side electrode of the low potential side switching element, respectively. In the power conversion device including the conductive third holding member and the fourth holding member that hold the switching element, the first holding member and the fourth holding member are electrically connected, and the second holding member and the second holding member are electrically connected. The three holding members are electrically connected, and only one of the electrically connected first holding member and the fourth holding member, or the electrically connected second holding member and the third holding member is grounded. It is characterized by being. The first to fourth insulating members and the first to fourth holding members are introduced for convenience in order to distinguish between the insulating member and the holding member.

  According to this configuration, a capacitor is configured by the electrode of the switching element, the first to fourth holding members, and the first to fourth insulating members. Among the components constituting these capacitors, the first holding member and the fourth holding member are electrically connected. Further, the second holding member and the third holding member are electrically connected. Furthermore, only one of the electrically connected first holding member and the fourth holding member, or the electrically connected second holding member and the third holding member is grounded, and the other is not grounded. Therefore, the amount of noise bypassed to the ground side can be suppressed compared to the case where all the capacitors are grounded as in the prior art. Therefore, common mode noise can be suppressed with a simple configuration.

  The power conversion device according to claim 2 is the power conversion device according to claim 1, wherein the first holding member and the fourth holding member that are electrically connected, or the second holding member that is electrically connected. And a third holding member, which is disposed adjacent to one grounded anti-switching element side and has a control means for controlling the high-potential side switching element and the low-potential side switching element. According to this configuration, the control means is disposed on the side opposite to the switching element of the grounded holding member. Noise generated by switching of the switching element is also radiated into space. However, a grounded holding member is disposed between the switching element and the control means. Therefore, radiation noise of the switching element can be reliably shielded.

  The power conversion device according to claim 3 is the power conversion device according to any one of claims 1 and 2, wherein the first holding member and the second holding member cool the high potential side switching element, and The holding member and the fourth holding member cool the low potential side switching element. According to this configuration, the switching element can be cooled by the holding member. Therefore, the temperature rise of the power conversion device can be suppressed.

  The power conversion device according to claim 4 is the power conversion device according to claim 3, wherein the first holding member, the second holding member, the third holding member, and the fourth holding member have a cooling medium flowing therein. It is characterized by that. According to this configuration, the cooling efficiency of the holding member can be improved. Therefore, the temperature rise of a power converter device can be suppressed more efficiently.

  The power conversion device according to claim 5 is the power conversion device according to any one of claims 1 to 4, wherein the first holding member and the fourth holding member are integrally formed, and the second holding member and The third holding member is formed integrally. According to this configuration, the number of parts can be reduced.

  Next, an embodiment is given and this invention is demonstrated in detail. In the present embodiment, an example in which the power conversion device according to the present invention is applied to a motor control device that controls a motor mounted on a vehicle will be described.

  First, the configuration of the motor control device will be described with reference to FIGS. Here, FIG. 1 is a circuit diagram of the motor control device according to the present embodiment. FIG. 2 is a perspective view for explaining the configuration of the power conversion circuit. FIG. 3 is a perspective view of the IGBT. FIG. 4 is a perspective view of another IGBT. FIG. 5 is an enlarged perspective view of the periphery of the IGBT in FIG. FIG. 6 is a perspective view for explaining the configuration of the electrode conversion circuit and the control circuit. In addition, the front-back direction, the left-right direction, and the up-down direction in the figure are introduced for convenience in order to describe the motor control device. Moreover, the white arrow in a figure shows the distribution direction of a refrigerant | coolant.

  A motor control device 1 (power conversion device) shown in FIG. 1 converts a DC low voltage output from a battery B1 into a three-phase AC voltage, supplies the same to a three-phase AC motor M1, and drives the three-phase AC motor M1. It is. That is, it is a device that converts DC power into AC power. The motor control device 1 includes a smoothing capacitor 10, a power conversion circuit 11, a drive circuit 12, and a control circuit 13 (control means).

The smoothing capacitor 10 is an element for smoothing the DC voltage of the battery B1. The positive terminal and the negative terminal of the smoothing capacitor 10 are connected to the positive terminal and the negative terminal of the battery B1, respectively. Note that the negative terminal of the battery B1 is floating without being grounded to the vehicle body.

  The power conversion circuit 11 is a circuit that converts the DC voltage of the battery B1 smoothed by the smoothing capacitor 10 into a three-phase AC voltage and supplies it to the three-phase AC motor M1. The power conversion circuit 11 includes IGBTs 110 to 115 and capacitors C1 to C12.

  The IGBTs 110 to 115 are switching elements for converting a DC voltage into a three-phase AC voltage by turning on and off. The IGBTs 110 and 113, the IGBTs 111 and 114, and the IGBTs 112 and 115 are connected in series, respectively. Specifically, the emitter terminals of the IGBTs 110 to 112 are connected to the collector terminals of the IGBTs 113 to 115, respectively. Three sets of IGBTs 110 and 113, IGBTs 111 and 114, and IGBTs 112 and 115 connected in series are connected in parallel. The collector terminals of the three IGBTs 110 to 112 are connected to the positive terminal of the smoothing capacitor 10, and the emitter terminals of the three IGBTs 113 to 115 are connected to the negative terminal of the smoothing capacitor 10. The gate terminals of the IGBTs 110 to 115 are connected to the drive circuit 12, respectively. In addition, U, V, and W phase terminals formed at series connection points of the IGBTs 110 and 113, the IGBTs 111 and 114, and the IGBTs 112 and 115 connected in series are respectively connected to the three-phase AC motor M1. Each phase coil of the three-phase AC motor M1 is floating from the vehicle body.

  Capacitors C <b> 1 to C <b> 12 are elements for bypassing high-frequency noise generated with switching of IGBTs 110 to 115. The capacitors C1 to C12 are configured by IGBTs 110 to 115, insulating members 14a to 141 described later, and coolers 15 and 16. One ends of the capacitors C1 and C2 are connected to the collector terminal and the emitter terminal of the IGBT 110, respectively. One ends of the capacitors C3 and C4 are connected to the collector terminal and the emitter terminal of the IGBT 113, respectively. One ends of the capacitors C5 and C6 are connected to the collector terminal and the emitter terminal of the IGBT 111, respectively. One ends of the capacitors C7 and C8 are connected to the collector terminal and the emitter terminal of the IGBT 114, respectively. One ends of the capacitors C9 and C10 are connected to the collector terminal and the emitter terminal of the IGBT 112, respectively. One ends of the capacitors C11 and C12 are connected to the collector terminal and the emitter terminal of the IGBT 115, respectively. On the other hand, the other ends of the capacitors C1, C4, C5, C8, C9, and C12 are connected to each other. The other ends of the capacitors C2, C3, C6, C7, C10, and C11 are connected to each other and grounded to the vehicle body.

  Here, the configuration of the capacitors C1 to C12 will be described in more detail.

  As shown in FIG. 2, the power conversion circuit 11 is structurally composed of IGBTs 110 to 115, insulating members 14 a to 14 l, and coolers 15 and 16.

  As shown in FIG. 3, the IGBT 110 (high potential side switching element) is a rectangular plate-shaped element. On the upper surface of the IGBT 110, a rectangular thin plate-shaped emitter electrode 110a (low potential side electrode) is formed. An emitter terminal 110b protruding forward is integrally formed at the left corner of the front end face of the emitter electrode 110a. A rectangular thin plate-like collector electrode 110c (high potential side electrode) is formed on the lower surface of the IGBT 110. A collector terminal 110d that projects forward is integrally formed at the right corner of the front end face of the collector electrode 110c. The IGBTs 111 and 112 (high potential side switching) have the same structure.

  As shown in FIG. 4, the IGBT 113 (low potential side switching element) connected in series to the IGBT 110 is a rectangular plate-like element like the IGBT 110. A rectangular thin plate-like collector electrode 113a (high potential side electrode) is formed on the upper surface of the IGBT 113. A collector terminal 113b protruding forward is integrally formed at the right corner of the front end face of the collector electrode 113a. A rectangular thin plate-like emitter electrode 113c (low potential side electrode) is formed on the lower surface of the IGBT 113. An emitter terminal 113d protruding forward is integrally formed at the left corner of the front end face of the emitter electrode 113c. The IGBTs 114 and 115 (low potential side switching elements) connected in series to the IGBTs 111 and 112 have the same structure.

  The insulating members 14a to 14l shown in FIG. 2 are rectangular thin plate members that are slightly larger than the collector and emitter electrodes for insulating the collector electrodes and emitter electrodes of the IGBTs 110 to 115 and the coolers 15 and 16, respectively.

  The coolers 15 and 16 are rectangular parallelepiped members that hold and cool the IGBTs 110 to 115 and have thermal conductivity and conductivity. In the coolers 15 and 16, flow passages 150 and 160 through which the refrigerant flows are formed in the left-right direction. The left ends of the flow passages 150 and 160 are connected by a pipe-like connecting member 17.

  As shown in FIG. 5, an insulation member 14a (second insulation member) is disposed in contact with the emitter electrode 110a of the IGBT 110, and an insulation member 14b (first insulation member) is disposed in contact with the collector electrode 110c. Yes. An IGBT 113 is disposed adjacent to the left side of the IGBT 110. An insulating member 14c (third insulating member) is disposed in contact with the collector electrode 113a of the IGBT 113, and an insulating member 14d (fourth insulating member) is disposed in contact with the emitter electrode 113c.

  Above the insulating members 14a and 14c, a cooler 15 (second holding member and third holding member) is in contact with the insulating members 14a and 14c in a state of facing the emitter electrode 110a and the collector electrode 113a, respectively. It is arranged. Below the insulating members 14b and 14d, the cooler 16 (first holding member and fourth holding member) is in contact with the insulating members 14b and 14d in a state of facing the collector electrode 110c and the emitter electrode 113c, respectively. It is arranged. The coolers 15 and 16 sandwich the IGBTs 110 to 115 from above and below via the insulating members 14a to 14l. The cooler 15 is grounded to the vehicle body. On the other hand, the cooler 16 is not grounded to the vehicle body.

  As a result, the emitter electrode 110a, the cooler 15, and the insulating member 14a constitute a capacitor C2 having one end connected to the emitter terminal 110b of the IGBT 110. The collector electrode 110c, the cooler 16, and the insulating member 14b constitute a capacitor C1 having one end connected to the collector terminal 110d of the IGBT 110. The collector electrode 113a, the cooler 15, and the insulating member 14c constitute a capacitor C3 having one end connected to the collector terminal 113b of the IGBT 113. The emitter electrode 113c, the cooler 16, and the insulating member 14d constitute a capacitor C4 having one end connected to the emitter terminal 113d of the IGBT 113.

  Similarly, capacitors C5 to C8 are configured by the electrodes of the IGBTs 111 and 114, the coolers 15 and 16 and the insulating members 14e to 14h shown in FIG. Further, capacitors C9 to C12 are configured by the electrodes of the IGBTs 112 and 115, the coolers 15 and 16, and the insulating members 14i to 14l.

  Since the cooler 15 is common and is grounded to the vehicle body, the other ends of the capacitors C2, C3, C5, C8, C9, and C12 are connected to each other and grounded to the vehicle body. On the other hand, since the cooler 16 is common and is not grounded to the vehicle body, the other ends of the capacitors C1, C4, C6, C7, C10, and C11 are connected to each other and floated from the vehicle body.

  The drive circuit 12 illustrated in FIG. 1 is a circuit that drives the power conversion circuit 11 based on a drive signal output from the control circuit 13. Specifically, this is a circuit that is provided for each of the IGBTs 110 to 115 and that turns the IGBTs 110 to 115 on and off. A drive signal input terminal of the drive circuit 12 is connected to the control circuit 13. The output terminals are connected to the gates of the IGBTs 110 to 115, respectively.

  The control circuit 13 is a circuit that outputs a drive signal for controlling on / off of the IGBTs 110 to 115 based on a command input from the outside. The drive signal output terminal of the control circuit 13 is connected to the drive signal input terminal of the drive circuit 12, respectively. As shown in FIG. 6, the control circuit 13 is mounted on the wiring board 18 disposed above the cooler 15 that is grounded to the vehicle body, that is, adjacent to the anti-IGBT side of the cooler 15.

  Next, the operation of the motor control device will be described with reference to FIGS.

  In FIG. 1, when a command is input from the outside, the motor control device 1 starts its operation. The control circuit 13 outputs a drive signal for turning on and off the IGBTs 110 to 115 based on the input command. The drive circuit 12 turns on and off the IGBTs 110 to 115 at a predetermined timing based on the drive signal output from the control circuit 13, and converts the DC voltage of the battery B1 into a three-phase AC voltage, thereby converting the three-phase AC motor M1. To supply.

  At this time, high-frequency noise is generated with the switching of the IGBTs 110 to 115. For example, noise generated due to the switching of the IGBT 113 is bypassed to the vehicle body via the path 1 that continues to the vehicle body via the stray capacitance Cbp on the negative electrode terminal side of the battery B1. Further, it is bypassed via the path 2 that continues to the IGBT 110 via the capacitors C4 and C1. Further, it is bypassed to the vehicle body via the U-phase terminal 3 and the path 3 continuing to the vehicle body via the U-phase coil Lu of the three-phase AC motor M1 and the stray capacitance Cmp. Further, it is bypassed to the vehicle body via a path 4 that leads to the vehicle body via the capacitor C3.

  By the way, when the capacitors connected to the collector terminal and the emitter terminal of the IGBT are all grounded to the vehicle body as in the prior art, all the noise generated due to the switching of the IGBT is bypassed to the vehicle body. However, in the motor control device 1, as shown in the path 2, part of the noise is not bypassed to the vehicle body. Therefore, common mode noise can be suppressed accordingly.

  Finally, specific effects will be described. According to the present embodiment, as described above, the amount of noise bypassed to the vehicle body can be suppressed as compared with the conventional art. Therefore, common mode noise can be suppressed while having a simple configuration.

  Further, according to the present embodiment, the control circuit 13 is mounted on the wiring board 18 disposed above the grounded cooler 15, that is, adjacent to the anti-IGBT side of the cooler 15. Noise generated with the switching of the IGBTs 110 to 115 is also radiated to the space. However, a grounded cooler 15 is disposed between the IGBTs 110 to 115 and the control circuit 13. Therefore, radiation noise of the IGBTs 110 to 115 can be reliably shielded.

  Further, according to the present embodiment, the IGBTs 110 to 115 are held and cooled by the coolers 15 and 16 having a holding function. Therefore, the temperature rise of the motor control device 1 can be suppressed.

  Furthermore, according to this embodiment, the coolers 15 and 16 are provided with the flow paths 150 and 160, and a refrigerant | coolant distribute | circulates. Therefore, the cooling efficiency of the coolers 15 and 16 can be improved.

  In addition, according to the present embodiment, the IGBTs 110 to 115 are integrally held by the coolers 15 and 16 having a holding function. Therefore, the number of parts can be reduced as compared with the case of holding each IGBT.

  In this embodiment, the other ends of the capacitors C1, C4, C5, C8, C9, and C12 are connected to each other and float from the vehicle body, and the other ends of the capacitors C2, C3, C6, C7, C10, and C11 are connected to each other. However, the present invention is not limited to this. Conversely, the other ends of the capacitors C2, C3, C6, C7, C10, and C11 are connected to each other and floated from the vehicle body, and the other ends of the capacitors C1, C4, C5, C8, C9, and C12 are connected to each other and connected to the vehicle body. It may be grounded. Only one of them needs to be grounded.

  Further, in the present embodiment, an example is given in which the other ends of the capacitors C1, C4, C5, C8, C9, and C12 are connected to each other and floated from the vehicle body, but are not limited thereto. The other ends of the capacitors C2 and C3, the other ends of the capacitors C6 and C7, and the other ends of the capacitors C10 and C11 may be connected and floated from the vehicle body. That is, the other ends of the capacitors C1, C4, C5, C8, C9, and C12 need only be connected to each phase and floated from the vehicle body.

It is a circuit diagram of the motor control device in the present embodiment. It is a perspective view for demonstrating the structure of a power converter circuit. It is a perspective view of IGBT. It is a perspective view of another IGBT. It is an expansion perspective view of IGBT periphery in FIG. It is a perspective view for demonstrating the structure of a power converter circuit and a control circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Motor control apparatus (power converter), 10 ... Smoothing capacitor, 11 ... Power converter circuit, 110-112 ... IGBT (high potential side switching element), 113-115 ... IGBT (low potential side switching element), 110a ... emitter electrode (low potential side electrode), 110b ... emitter terminal, 110c ... collector electrode (high potential side electrode), 110d ... collector terminal, 113a ... collector electrode (high potential side electrode), 113b ... collector terminal, 113c ... emitter electrode (low potential side electrode), 113d ... emitter terminal, 12 ... drive circuit, 13 ... Control circuit (control means), 14a, 14e, 14i ... insulating member (second insulating member), 14b, 14f, 14j ... insulating member (first insulating member), 14c, 1 g, 14k ... insulating member (third insulating member), 14d, 14h, 14l ... insulating member (fourth insulating member), 15, 16 ... cooler (holding member), 150, 160,. -Flow path, 17 ... connecting member, 18 ... wiring board, B1 ... battery, M1 ... three-phase AC motor, Cmp, Cbp ... stray capacitance

Claims (5)

A high potential side switching element having a high potential side electrode and a low potential side electrode;
A low potential side switching element having a high potential side electrode and a low potential side electrode, wherein the high potential side electrode is electrically connected to the low potential side electrode of the high potential side switching element;
A first insulating member and a second insulating member disposed in contact with the high potential side electrode and the low potential side electrode of the high potential side switching element,
A third insulating member and a fourth insulating member disposed in contact with the high potential side electrode and the low potential side electrode of the low potential side switching element,
The high potential side switching element is disposed in contact with the first insulating member and the second insulating member, respectively, in a state of facing the high potential side electrode and the low potential side electrode of the high potential side switching element. A first holding member and a second holding member having conductivity for holding the element, and the third insulating member and the low potential side electrode in a state of facing the high potential side electrode and the low potential side electrode, respectively. In a power converter comprising: a third holding member and a fourth holding member that are disposed in contact with the fourth insulating member and have conductivity to hold the low potential side switching element.
The first holding member and the fourth holding member are electrically connected;
The second holding member and the third holding member are electrically connected;
Only one of the first holding member and the fourth holding member that are electrically connected, or the second holding member and the third holding member that are electrically connected is grounded. A power converter.   Of the electrically connected first holding member and the fourth holding member, or of the electrically connected second holding member and the third holding member, on one anti-switching element side that is grounded The power converter according to claim 1, further comprising a control unit that is arranged adjacent to and controls the high-potential side switching element and the low-potential side switching element. The first holding member and the second holding member cool the high potential side switching element,
3. The power conversion device according to claim 1, wherein the third holding member and the fourth holding member cool the low potential side switching element. 4.   The power conversion device according to claim 3, wherein a cooling medium flows through the first holding member, the second holding member, the third holding member, and the fourth holding member. The first holding member and the fourth holding member are integrally formed,
The power converter according to claim 1, wherein the second holding member and the third holding member are integrally formed.

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