JP5669677B2 - Power conversion device and power conversion module - Google Patents

Description

  The present invention relates to a power conversion device.

FIG. 1 is a diagram illustrating a configuration of a power conversion device including an inverter. Power converter 2 of FIG. 1 is a converter of three phases, U-phase, V-phase, and the power transistor _M1 U _{to M1 W,} M2 U -M2 power module _{4 W} is built of W-phase, the power transistor M1 comprising a _{U ~M1 W, M2 U ~M2} gate drive circuit 6 for driving the _W, the smoothing capacitor C1 and the snubber circuit 8 is an electrolytic capacitor. In FIG. 1, only the U phase is shown, and the V phase and the W phase are omitted.

JP-A-10-225140 JP 2004-112999 A

Upper power supply line LP and lower power supply line LN are connected to the anode and cathode of power supply 5, respectively. The power module 4 includes, for each phase, a high-side transistor M1 and a low-side transistor M2 that are sequentially provided in series between the upper power supply line LP and the lower power supply line LN. Focusing on the U phase, when the high side transistor M1 _U is on, the U phase output OUTU is at a high level, and when the low side transistor M2 _U is on, the U phase output OUTU is at a low level.

  If noise is superimposed on the control signals G1 and G2 for the power transistors M1 and M2 generated by the gate drive circuit 6, the power transistors M1 and M2 may operate unintentionally. As a countermeasure against this, it is desirable that the smoothing capacitor C1 and the snubber circuit 8 are arranged in the immediate vicinity of the power module 4.

  On the other hand, the power module 4 and the smoothing capacitor C <b> 1 that is an electrolytic capacitor generate heat in the operating state of the power converter 2. Therefore, if they are arranged close to each other, they may affect each other thermally and cause the temperature of both to rise. Excessive temperature rise is undesirable because it affects the life of electrolytic capacitors and power modules.

  The present invention has been made in view of such problems, and one of the exemplary purposes of an aspect thereof is to provide a power conversion device capable of suppressing temperature rise while taking measures against noise and surge.

  An embodiment of the present invention relates to a power conversion device that supplies power to a load. The power converter is electrically connected to the upper and lower power lines, one electrolytic capacitor electrically connected between the upper and lower power lines, and the upper and lower power lines. A power module having an upper power supply terminal and a lower power supply terminal connected to each other and including at least one power transistor provided between the upper power supply terminal and the lower power supply terminal, and driving at least one power transistor A gate drive circuit, a snubber circuit electrically connected to the upper power line and the lower power line, a power module is mounted on the first surface, and components of the gate drive circuit and the snubber circuit are mounted on the second surface. A first substrate to be mounted, a second substrate on which an electrolytic capacitor is mounted on the first surface, and an upper power supply line A first bus bar for supporting the second substrate substantially parallel to the first substrate and at a predetermined interval, and forming a part of the lower power supply line. And a second bus bar that is supported substantially parallel to the substrate and at a predetermined interval.

  According to this aspect, the first substrate on which the power module is mounted and the second substrate on which the electrolytic capacitor is mounted are arranged in parallel with an interval using the first and second bus bars. And the thermal distance between the power modules can be increased, and the temperature rise can be suppressed. Although the electrolytic capacitor is physically mounted at a position away from the power module, it is disposed at an electrically close position because it is connected via the bus bar, and the components of the snubber circuit are the first board. Since it is mounted above, the electrical distance to the power module is very close. Therefore, countermeasures against noise and surge are taken by the electrolytic capacitor and the snubber circuit.

  Each of the first and second bus bars is connected to a first support member whose one end is electrically and mechanically connected to the first substrate and whose one end is electrically and mechanically connected to the first substrate. The second support member is electrically and mechanically connected to the other end of the first support member and the other end of the second support member, and is supported substantially parallel to the first substrate by the first and second support members. And a plate. The plates of the first and second bus bars may be supported in the same plane substantially parallel to the first substrate, and the second substrate may be provided on the plates of the first and second bus bars.

  The plate of the first bus bar and the plate of the second bus bar may be arranged at a predetermined interval in the same plane.

  The plate of the first bus bar and the plate of the second bus bar may be disposed in close contact with each other via an insulator in the same plane.

Another aspect of the present invention relates to a power conversion module. This power conversion module includes a plurality of the above-described power conversion devices. The plate of the first bus bar provided in each of the plurality of power conversion devices may be configured integrally, and the plate of the second bus bar provided in each of the plurality of power conversion devices may be configured integrally.
By sharing the bus bar plate among the plurality of power conversion devices, there is an advantage that the electrolytic capacitor for smoothing can be shared among the plurality of power conversion devices.

  Note that any combination of the above-described constituent elements and the constituent elements and expressions of the present invention replaced with each other among methods, apparatuses, systems, and the like are also effective as an aspect of the present invention.

  According to the present invention, it is possible to suppress an increase in temperature while taking measures against noise and surge.

It is a figure which shows the structure of power converters including an inverter. Fig.2 (a)-(c) is a figure which shows the structure of the power converter device which concerns on embodiment. It is a perspective view of a part of a power converter. It is a figure which shows the structure of a heavy machine or a portable device provided with the power conversion module which concerns on embodiment. It is a perspective view which shows a part of power conversion module of FIG.

  Fig.2 (a)-(c) is a figure which shows the structure of the power converter device 2 which concerns on embodiment. 2A is a plan view of the power conversion device 2, and FIGS. 2B and 2C are side views of the power conversion device 2. FIG. FIG. 3 is a perspective view of a part of the power conversion device 2.

  The power converter 2 supplies power to a load (not shown). An equivalent circuit diagram of the power conversion device 2 is, for example, as described in FIG.

  The power converter 2 includes an upper power line LP, a lower power line LN, a smoothing electrolytic capacitor C1, a power module 4, a gate drive circuit 6, a snubber circuit 8, a first substrate 20, a second substrate 22, A bus bar 24 and a second bus bar 26 are provided. First, the electrical connection relationship of each member will be described with reference to FIG.

  As shown in FIG. 1, the upper power supply voltage LP and the lower power supply voltage VSS are supplied from the power supply 5 to the upper power supply line LP and the lower power supply line LN. The smoothing electrolytic capacitor C1 is electrically connected between the upper power supply line LP and the lower power supply line LN. Although the number of electrolytic capacitors C1 may be one, since the volume increases as the capacity increases, a large capacity is realized by connecting a plurality of electrolytic capacitors C1 in parallel.

  The power module 4 has an upper power supply terminal P electrically connected to the upper power supply line LP, a lower power supply terminal N electrically connected to the lower power supply line LN, and the upper power supply terminal P and the lower power supply. At least one power transistor M1, M2 provided between the terminals N is incorporated. The power module 4 may be single-phase or multi-phase, and the number of phases is not limited.

  The gate drive circuit 6 drives the power transistors M1 and M2 constituting the power module 4. The snubber circuit 8 is a protection circuit that absorbs a transient high voltage generated when the power transistors M1 and M2 are switched, and is electrically connected to the upper power supply line LP, the lower power supply line LN, and the output terminal OUT. . For example, in the configuration example of FIG. 1, the capacitor C2 forms a C snubber, and the resistors R1, R2, capacitors C3, C4, and diodes D1, D2 form an RCD snubber. The configuration of the snubber circuit 8 is not particularly limited and may be an arbitrary configuration.

  Next, with reference to FIGS. 2A to 2C, the electrical and mechanical connection relationships of the respective members will be described. 2A to 2C, the upper power supply line LP and the lower power supply line LN are omitted.

  The power module 4 is mounted on the first surface S1 of the first substrate 20, and the components C2 to C4, R1, R2, D1, and D2 of the gate drive circuit 6 and the snubber circuit 8 are mounted on the opposite second surface S2. Implemented. The arrangement of the components of the gate drive circuit 6 and the snubber circuit 8 on the second surface S2 is not particularly limited. A heat sink 10 for heat dissipation is in close contact with the surface opposite to the first surface S1 of the power module 4 and is thermally coupled thereto.

  A plurality of electrolytic capacitors C <b> 1 are mounted on the first surface S <b> 3 of the second substrate 22. The first bus bar 24 forms a part of the upper power supply line LP and supports the second substrate 22 substantially in parallel with the first substrate 20 with a predetermined distance d. The distance d may be determined in consideration of the height of the circuit component mounted on the second surface S2 of the first substrate 20 and the heat dissipation of each component.

  The second bus bar 26 forms a part of the lower power supply line LN, and supports the second substrate 22 substantially parallel to the first substrate 20 with a predetermined distance d.

  Specifically, as shown in FIG. 3, the first bus bar 24 includes a first support member 24a, a second support member 24b, and a plate 24c. Of course, the first support member 24a, the second support member 24b, and the plate 24c are all conductors. The first support member 24 a and the plate 24 c are conductor plates bent in a crank shape or a “U” shape, and one end of each plate is formed on the first surface S 1 of the first substrate 20. It is electrically and mechanically connected to a wiring pattern (not shown) forming the line LP. The plate 24c is electrically and mechanically connected to the other end of each of the first support member 24a and the second support member 24b, and is supported substantially parallel to the first substrate 20 by them. The second bus bar 26 is configured in the same manner as the first bus bar 24. The plates 24 c and 26 c of the first bus bar 24 and the second bus bar 26 are supported in the same plane substantially parallel to the first substrate 20. The arrangement of the support members 24a, 24b, 26a, 26b is not particularly limited. The plate 24c of the first bus bar 24 and the plate 26c of the second bus bar 26 are arranged at a predetermined interval L in the same plane and are insulated from each other.

  As shown in FIGS. 2B and 2C, the second substrate 22 is provided on the plates 24c and 26c of the first bus bar 24 and the second bus bar 26, respectively. A wiring pattern (not shown) that is part of the upper power supply line LP is formed on the second substrate 22 and is electrically connected to the first bus bar 24. Similarly, a wiring pattern (not shown) that is a part of the lower power supply line LN is formed on the second substrate 22 and is electrically connected to the second bus bar 26. The electrolytic capacitor C1 is electrically connected to the wiring pattern of the upper power supply line LP formed on the second substrate 22 and the wiring pattern of the lower power supply line LN.

The above is the configuration of the power conversion device 2. Next, the operation and advantages will be described.
The power transistors M1 and M2 of the power module 4 are driven by the gate drive circuit 6.
Although the electrolytic capacitor C1 is physically mounted at a position distant from the power module 4, it can be said that the electrolytic capacitor C1 is disposed at an electrically close position because it is connected via the bus bars 24 and 26. This is because the bus bar impedance is sufficiently smaller than the impedance of the wiring pattern on the printed circuit board. Further, since the components of the snubber circuit 8 are mounted on the second surface S2 of the first substrate 20, the electrical distance from the power module 4 mounted on the first surface S1 is short. Therefore, both the electrolytic capacitor C1 and the snubber circuit 8 can be disposed at positions that are electrically close to the power module 4, and the power transistor M1 and the power transistor M2 are prevented from malfunctioning due to surge or noise. Can do.

  The power module 4 generates heat by driving the power transistors M1 and M2. A part of the heat is dissipated by the heat sink 10, but the remaining heat is accumulated in the power module 4 and the temperature of the power module 4 rises. Further, the electrolytic capacitor C1 also generates heat by being charged and discharged. However, in the power conversion device 2 according to the embodiment, the electrolytic capacitor C1 and the power module 4 are arranged at physically separated positions, and the mutual thermal influence is reduced.

  That is, when attention is paid to the electrolytic capacitor C1, the heat is released to the space above the electrolytic capacitor C1. In addition, since the electrolytic capacitor C1 is connected to the first bus bar 24 and the second bus bar 26 via the second substrate 22, the first bus bar 24 and the second bus bar 26 function as a heat sink for the electrolytic capacitor C1. There is expected. In particular, in the embodiment, since the total area of the plate 24c and the plate 26c is approximately the same as that of the first substrate 20 and the second substrate 22, heat can be effectively radiated.

  The power module 4 is radiated by the heat sink 10 and can be cooled by the air flowing through the space between the first substrate 20 and the second substrate 22. Further, the plate 24 c and the plate 26 c can also be cooled by the air flowing through the space between the first substrate 20 and the second substrate 22. That is, since the space between the first substrate 20 and the second substrate 22 serves as an air flow path, the entire power conversion device 2 can be effectively cooled.

  It should also be noted that the first support members 24a and 26a and the second support members 24b and 26b are formed with a width narrower than that of the plates 24c and 26c. Thereby, it can cool effectively, without the flow of air being interrupted by support member 24a, 26a, 24b, 26b.

  Thus, according to the power conversion device 2 according to the embodiment, the electrolytic capacitor C1 and the power module 4 can be effectively cooled, and the distance between them is increased. It is possible to prevent the capacitor C1 from being heated and, conversely, the power module 4 from being heated by the heat generated by the electrolytic capacitor C1. Thereby, the lifetime of components including the power module 4 and the electrolytic capacitor C1 can be extended.

  FIG. 4 is a diagram illustrating a configuration of a heavy machine or a transporter including the power conversion module 3 according to the embodiment. FIG. 5 is a perspective view showing a part of the power conversion module 3 of FIG. For example, heavy machinery and transporters (hereinafter collectively referred to as heavy machinery 1) including forklifts and crane vehicles have a motor 40 for driving a hydraulic pump for cargo handling and a motor 42 for wheels for self-propelled driving. Therefore, these heavy machinery 1 requires two systems of power conversion devices.

  The power conversion module 3 includes power conversion devices 2 a and 2 b for driving the two motors 40 and 42, and is modularized on one board 7. The configuration of each of the power conversion devices 2a and 2b has basically the same configuration as that of the power conversion device 2 described above. A characteristic of the power conversion module 3 is that the plate 24c of the first bus bar 24 provided in each of the plurality of power conversion devices 2a and 2b is integrally formed as a single plate. Similarly, the plate 26c of the second bus bar 26 of each of the power conversion devices 2a and 2b is also integrally configured as a single plate.

  According to this power conversion module 3, in each of power converter device 2a, 2b, while being able to acquire the above-mentioned effect, the following effects can be acquired as a whole.

  In many applications, the two motors 40, 42 are rarely driven at the same time, and one of the power converters 2a, 2b is in operation and the other is in a dormant state. Therefore, during operation of the power conversion device 2a, heat generated by the power conversion device 2a can be radiated not only by the power conversion device 2a portion of the plates 24c and 26c but also by the power conversion device 2b portion. That is, since the plates of the same polarity of the power conversion devices 2a and 2b are configured as a single plate, the heat dissipation effect by the plates 24c and 26c is increased.

  Further, there is an advantage that the electrolytic capacitors C1 provided in each of the power conversion devices 2a and 2b are shared with each other. That is, during operation of the power conversion device 2a, in addition to the electrolytic capacitor C1 on the power conversion device 2a side, the electrolytic capacitor C1 provided on the power conversion device 2b side also suppresses voltage fluctuations between the power supply lines LP and LN. Therefore, the effective capacitance value of the electrolytic capacitor C1 is doubled.

  The present invention has been described based on the embodiments. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of the respective constituent elements and processing processes, and such modifications are within the scope of the present invention. is there. Hereinafter, such modifications will be described.

  In the embodiment, the first bus bar 24 is divided into the first support member 24a, the second support member 24b, and the plate 24c, and they are electrically and mechanically connected. , And may be integrally formed as a single conductor. In this case, a plurality of members may be welded, or the first bus bar 24 may be formed by bending a single conductor plate. The same applies to the second bus bar 26.

  In the embodiment, the case where the plate 24c and the plate 26c are arranged with a gap L between them is described, but the plate 24c and the plate 26c may be arranged in close contact with an insulator sandwiched therebetween. In this case, since the plate 24c and the plate 26c mechanically function as a single plate, there is an advantage that it is difficult to vibrate.

  In the embodiment, the case where the power conversion module 3 includes the two power conversion devices 2 has been described. However, more power conversion devices 2 may be modularized.

  In the above, this invention was demonstrated based on the Example. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, various modifications are possible, and such modifications are within the scope of the present invention. By the way.

2 ... Power conversion device, 3 ... Power conversion module, M1, M2 ... Power transistor, 4 ... Power module, 6 ... Gate drive circuit, 8 ... Snubber circuit, 10 ... Heat sink, LP ... Upper power supply line, LN ... Lower power supply Line, 20 ... first substrate, 22 ... second substrate, 24 ... first bus bar, 24a ... first support member, 24b ... second support member, 24c ... plate, 26 ... second bus bar, 26a ... first support member , 26b, second support member, 26c, plate, C1, electrolytic capacitor, S1, first surface, S2, second surface, S3, first surface.

Claims (5)

A power converter for supplying power to a load,
An upper power line and a lower power line;
At least one electrolytic capacitor electrically connected between the upper power line and the lower power line;
At least one power provided between the upper power supply terminal and the lower power supply terminal, and having an upper power supply terminal and a lower power supply terminal electrically connected to the upper power supply line and the lower power supply line, respectively. A power module with a built-in transistor;
A gate drive circuit for driving the at least one power transistor;
A snubber circuit electrically connected to the upper power line and the lower power line;
A first substrate on which the power module is mounted on the first surface and components of the gate drive circuit and the snubber circuit are mounted on the second surface;
A second substrate on which the electrolytic capacitor is mounted on the first surface;
A first bus bar that forms part of the upper power supply line and supports the second substrate substantially parallel to the first substrate at a predetermined interval;
A second bus bar that forms part of the lower power supply line and supports the second substrate substantially parallel to the first substrate at a predetermined interval;
A power conversion device comprising: The first bus bar and the second bus bar are respectively
A first support member having one end electrically and mechanically connected to the first substrate;
A second support member to be connected, one end of which is electrically and mechanically connected to the first substrate;
A plate electrically and mechanically connected to the other end of the first support member and the other end of the second support member, and supported by the first and second support members substantially parallel to the first substrate. When,
Including
The plates of the first and second bus bars are supported in the same plane substantially parallel to the first substrate,
The power converter according to claim 1, wherein the second substrate is provided on the plate of each of the first and second bus bars.   The power converter according to claim 2, wherein the plate of the first bus bar and the plate of the second bus bar are arranged at a predetermined interval in the same plane.   The power converter according to claim 2, wherein the plate of the first bus bar and the plate of the second bus bar are arranged in close contact with each other through an insulator in the same plane. A plurality of power conversion devices according to any one of claims 2 to 3,
The plate of the first bus bar provided in each of the plurality of power converters is integrally configured,
The power conversion module, wherein the plates of the second bus bars provided in each of the plurality of power conversion devices are integrally formed.

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