JP7319945B2 - power converter - Google Patents

Description

The present invention relates to power converters.

Inverters that convert DC power to AC power are becoming higher output, higher frequency, and smaller, so there is a need to suppress electromagnetic noise. is added. The noise elimination filter has a configuration in which a busbar is inserted through the noise elimination core, and the cross-sectional area of the busbar becomes smaller around the noise elimination core, increasing heat generation. This heat flows into the noise elimination capacitor, and the noise elimination capacitor receives heat. Therefore, it is necessary to efficiently cool the periphery of the noise removal filter and reduce the influence of heat from the inverter.

Patent Literature 1 discloses a power conversion device that improves heat radiation performance by arranging a cooling portion on the lower surface of a noise filter module, thereby enabling a higher output of an inverter.

International publication WO2018/116667

In the above-mentioned device described in Patent Document 1, when the cooling part cannot be arranged on the bottom surface of the noise filter module due to the demand for miniaturization of the device, the noise elimination capacitor and the noise elimination core could not be cooled efficiently. .

A power conversion device according to the present invention includes a power semiconductor circuit section for converting DC power into AC power, a smoothing capacitor for smoothing the DC power, and arranged on the opposite side of the smoothing capacitor from the power semiconductor circuit section. and a coolant flow path for cooling the power semiconductor circuit, the filter circuit including a noise elimination capacitor and a noise elimination core, the smoothing capacitor comprising a first smoothing a capacitor section and a second smoothing capacitor section, and between the noise elimination capacitor and the noise elimination core, and between the first smoothing capacitor section and the second smoothing capacitor section; A first partition is provided, and the first partition is thermally connected to the coolant channel.

According to the present invention, it is possible to efficiently cool the noise elimination capacitor and the noise elimination core while satisfying the demand for miniaturization of the device.

1 is a circuit configuration diagram of a power converter according to a first embodiment; FIG. 1 is a perspective view of a power converter according to a first embodiment; FIG. 1 is an exploded view of a power conversion device according to a first embodiment; FIG. It is a bottom perspective view of the power conversion device according to the first embodiment. 3 is a perspective view showing a first DC busbar and a second DC busbar according to the first embodiment; FIG. 1 is a top view of a power conversion device according to a first embodiment; FIG. (A) and (B) are a top view and a side view of the power converter according to the first embodiment. (A) and (B) are a top view and a side view of the power converter according to the first embodiment. It is a perspective view of the power converter device which concerns on 2nd Embodiment. FIG. 7 is an exploded view of a power conversion device according to a second embodiment; It is a top view of the power converter device which concerns on 2nd Embodiment. (A) and (B) are a top view and a side view of a power converter according to a second embodiment. It is a perspective view of the power converter device which concerns on 3rd Embodiment. FIG. 11 is an exploded view of a power conversion device according to a third embodiment; (A) and (B) are a top view and a side view of a power converter according to a third embodiment.

Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are examples for explaining the present invention, and are appropriately omitted and simplified for clarity of explanation. The present invention can also be implemented in various other forms. Unless otherwise specified, each component may be singular or plural.

The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. As such, the present invention is not necessarily limited to the locations, sizes, shapes, extents, etc., disclosed in the drawings.

[First Embodiment]
FIG. 1 is a circuit configuration diagram of a power conversion device 1. As shown in FIG.
DC power is input to the power converter 1 from a DC power supply 2 . The power conversion device 1 converts input DC power into AC power and outputs the AC power to the motor generator 5 to drive the motor generator 5 . In addition, when the motor generator 5 rotates due to an external force, the power converter 1 converts AC power into DC power, stores the power in the DC power supply 2, and regenerates it.

The power conversion device 1 includes an inverter main circuit 3 that converts DC power into AC power, and a filter circuit section 20 that suppresses electromagnetic noise generated by the inverter main circuit 3 during power conversion operation.

The inverter main circuit 3 is composed of a power semiconductor circuit section 4 that constitutes an inverter, and a smoothing capacitor 50 that smoothes the DC power.

The power semiconductor circuit unit 4 is composed of a switching element and a power semiconductor module having a diode element that circulates current from the motor generator 5. The diode element also has a function of converting AC power into DC power during regeneration.

The power semiconductor circuit section 4 includes power semiconductor modules 4a, 4b, and 4c. Power semiconductor module 4 a is connected to the U phase of motor generator 5 . Power semiconductor module 4 b is connected to the V phase of motor generator 5 . Power semiconductor module 4 c is connected to the W phase of motor generator 5 .

The smoothing capacitor 50 is connected between the power semiconductor circuit section 4 and the filter circuit section 20 , performs smoothing when converting DC power into AC power, and supplies the smoothed DC power to the power semiconductor circuit section 4 . .
The second DC bus bar 11 is a power transmission path connected between the smoothing capacitor 50 , the power semiconductor circuit section 4 and the filter circuit section 20 .

The filter circuit section 20 is arranged between the DC power supply terminal 6 and the smoothing capacitor 50, and removes electromagnetic noise, that is, normal mode noise and common mode noise, generated when the power semiconductor circuit section 4 operates for power conversion. The filter circuit section 20 includes a noise elimination capacitor 21 and a noise elimination core 26 . The first DC bus bar 10 is electrically connected to the noise elimination capacitor 21 , inserted through the through hole of the noise elimination core 26 , and connected to the second DC bus bar 11 .

The noise elimination capacitor 21 is composed of an X capacitor 22 and Y capacitors 23 and 24 . The X capacitor 22 is connected between the positive-side conductor and the negative-side conductor of the first DC bus bar 10 and smoothes power of a frequency higher than that smoothed by the smoothing capacitor 50 . X capacitor 22 removes normal mode noise.

Y capacitor 23 is connected between the positive electrode side conductor of first DC bus bar 10 and GND terminal 25 . A GND terminal 25 is a ground terminal in the circuit of the power converter 1 . Y capacitor 24 is connected between the negative electrode side conductor of first DC bus bar 10 and GND terminal 25 . Y capacitors 23 and 24 remove common mode noise.

The noise elimination core 26 is a core member that suppresses electromagnetic noise by absorbing fluctuations in the current flowing through the first DC bus bar 10 . First DC bus bar 10 is connected to DC power supply 2 via DC power supply terminal 6 .

FIG. 2 is a perspective view of the power converter 1. FIG.
The metal case 7 is a case of the power converter 1 and accommodates the inverter main circuit 3 and the filter circuit section 20 .
The filter circuit section 20 is arranged on the side opposite to the power semiconductor circuit section 4 with the smoothing capacitor 50 interposed therebetween. Y capacitors 23 and 24 (see FIG. 1) are connected to GND terminal 25 . First DC bus bar 10 is connected to DC power supply 2 via DC power supply terminal 6 .

The first DC bus bar 10 is placed on the noise elimination capacitor 21 and inserted into the noise elimination core 26 arranged in parallel with the noise elimination capacitor 21 , and then connected to the second DC bus bar 11 .
The second DC bus bar 11 is arranged on the smoothing capacitor 50 and connected to the power semiconductor circuit section 4 . The AC bus bar 12 is a power transmission path through which AC power from the power semiconductor circuit unit 4 is output, and is connected to the motor generator 5 (see FIG. 1).

FIG. 3 is an exploded view of the power converter 1. As shown in FIG.
The first DC bus bar 10 is composed of a positive electrode conductor 10p and a negative electrode conductor 10n, and is covered with a mold resin material 10m for insulation and fixing. The second DC bus bar 11 is composed of a positive electrode conductor 11p and a negative electrode conductor 11n, and is covered with a mold resin material 11m for insulation and fixing.

AC bus bar 12 is a power transmission path connected between power semiconductor circuit unit 4 and motor generator 5 . Of the AC busbars 12 , the AC busbar 12 a is connected to the power semiconductor module 4 a and the U-phase of the motor generator 5 . AC bus bar 12 b is connected to power semiconductor module 4 b and V phase of motor generator 5 . AC bus bar 12 c is connected to power semiconductor module 4 b and W phase of motor generator 5 .

The smoothing capacitor 50 is composed of a first smoothing capacitor section 51 and a second smoothing capacitor section 52 . An X capacitor 22 and Y capacitors 23 and 24 are arranged on the opposite side of the power semiconductor modules 4a, 4b and 4c with the smoothing capacitor 50 interposed therebetween.

A coolant channel 8 is provided in the metal case 7 , and the power semiconductor modules 4 a , 4 b , and 4 c are thermally connected to the coolant channel 8 and cooled by the coolant flowing through the coolant channel 8 .
In addition, the metal case 7 is provided with a thermally conductive first partition 60 between the noise elimination capacitor 21 and the noise elimination core 26 and between the first smoothing capacitor section 51 and the second smoothing capacitor section 52. , and the first partition 60 is thermally connected to the coolant channel. The first partition wall 60 may be formed integrally with the metal case 7 or may be formed separately from the metal case 7 .

The first DC bus bar 10 is in contact with the first partition wall 60 via the first heat conductive member 61 . The first thermally conductive member 61 is a thermally conductive member such as a heat radiating sheet or heat radiating grease. Heat is radiated from the first partition wall 60 to the coolant channel 8 .

The second DC bus bar 11 is in contact with the first partition wall 60 via the second thermally conductive member 62 . The second thermally conductive member 62 is a thermally conductive member such as a heat radiating sheet or heat radiating grease. Heat is radiated from the first partition wall 60 to the coolant flow path 8 .

FIG. 4 is a perspective view of the bottom surface of the power converter 1. FIG.
Coolant flow paths 8 for cooling the power semiconductor modules 4a, 4b, and 4c are provided on the bottom surface of the metal case 7 . The power semiconductor modules 4a, 4b, and 4c are cooled by the coolant flowing through the coolant flow path 8. As shown in FIG.

FIG. 5 is a perspective view showing the first DC bus bar 10 and the second DC bus bar 11. FIG.
The first DC bus bar 10 is configured by stacking a positive electrode conductor 10p and a negative electrode conductor 10n insulated from each other, and covered with a mold resin material for insulation and fixing. The second direct-current bus bar 11 is formed by stacking a positive electrode conductor 11p and a negative electrode conductor 11n insulated from each other, and is covered with a molding resin material for insulation and fixing. A positive conductor 10 p of the first DC bus bar 10 is connected to a positive conductor 11 p of the second DC bus bar 11 . The negative conductor 10n of the first DC busbar 10 is connected to the negative conductor 11n of the second DC busbar 11 .

FIG. 6 is a top view of the power converter 1. FIG. In FIG. 6, the arrow Z indicates the path of heat conduction with the first DC bus bar 10 and the second DC bus bar 11 removed.
The heat generated by the first smoothing capacitor portion 51 and the second smoothing capacitor portion 52 is radiated to the refrigerant flow path 8 of the power semiconductor circuit portion 4 via the thermally conductive first partition wall 60 . Furthermore, the heat generated by the noise elimination capacitor 21 and the noise elimination core 26 is radiated to the coolant flow path 8 of the power semiconductor circuit section 4 via the thermally conductive first partition wall 60 .

In the case where this embodiment is not applied, the central portion of the mounting location of the smoothing capacitor 50 tends to accumulate heat and becomes a thermal bottleneck. In contrast, in the present embodiment, a heat dissipation path is formed by providing the first partition 60 between the first smoothing capacitor section 51 and the second smoothing capacitor section 52, so that the temperature distribution of the smoothing capacitor 50 is localized. It is difficult to increase the temperature and can be made uniform. Moreover, when the present embodiment is not applied, the size of the apparatus is increased by providing the cooling section on the lower surface of the filter circuit section 20 (the noise elimination capacitor 21 and the noise elimination core 26). On the other hand, in the present embodiment, a heat dissipation path is formed by providing the first partition wall 60 between the noise elimination capacitor 21 and the noise elimination core 26, so that the device can be made smaller. And the temperature distribution of the noise elimination core 26 is less likely to become locally high and can be made uniform.

7A is a top view of the power conversion device 1, and FIG. 7B is a side view of the power conversion device 1. FIG. In FIG. 7A, arrows X indicate paths of heat conduction of the noise elimination capacitor 21 and the noise elimination core 26 with the first DC bus bar 10 and the second DC bus bar 11 removed. In FIG. 7B, arrows X indicate paths of heat conduction of the noise elimination capacitor 21 and the noise elimination core 26 with the first DC bus bar 10 and the second DC bus bar 11 attached.

As shown in FIG. 7B, the first DC busbar 10 is in contact with the first partition wall 60 via the first thermally conductive member 61 . Therefore, as shown in FIGS. 7A and 7B, the heat conducted from the noise elimination capacitor 21 and the noise elimination core 26 to the first DC bus bar 10 and the heat generated by the first DC bus bar 10 are referred to as the first heat. The heat is conducted to the first partition wall 60 via the conductive member 61 and radiated to the coolant channel 8 .

8A is a top view of the power conversion device 1, and FIG. 8B is a side view of the power conversion device 1. FIG. In FIG. 8A, arrows Y indicate paths of heat conduction in the first smoothing capacitor section 51 and the second smoothing capacitor section 52 with the first DC bus bar 10 and the second DC bus bar 11 removed. In FIG. 7B, the arrow Y indicates the heat conduction path of the first smoothing capacitor section 51 and the second smoothing capacitor section 52 with the first DC bus bar 10 and the second DC bus bar 11 attached.

The second DC bus bar 11 is in contact with the first partition wall 60 via the second thermally conductive member 62 . Therefore, as shown in FIGS. 8A and 8B, the heat generated by the first smoothing capacitor section 51 and the second smoothing capacitor section 52 is transferred from the second DC bus bar 11 through the second thermally conductive member 62. Then, the heat is conducted to the first partition wall 60 and radiated to the coolant channel 8 .

[Second embodiment]
FIG. 9 is a perspective view of the power converter 1 according to the second embodiment. In the second embodiment, a second partition wall 70 is provided in addition to the configuration of the first embodiment. 1 of the first embodiment, the perspective view of the bottom surface of the power conversion device 1 shown in FIG. 4, the first DC bus bar 10 and the second DC bus bar 10 shown in FIG. Since the perspective view showing the DC bus bar 11 is the same as in the second embodiment, the illustration is omitted. Also, the same reference numerals are given to the same parts as in the first embodiment, and the description thereof will be omitted.

As shown in FIG. 9 , a thermally conductive second partition 70 is provided between the filter circuit section 20 (the noise elimination capacitor 21 and the noise elimination core 26 ) and the smoothing capacitor 50 . Other configurations are the same as those of the perspective view of the power converter 1 shown in FIG. 2 of the first embodiment.

FIG. 10 is an exploded view of the power converter 1 according to the second embodiment.
A thermally conductive second partition 70 is part of the metal case 7 and is arranged between the filter circuit section 20 and the smoothing capacitor 50 . A third thermally conductive member 71 is provided on the second partition 70 , and the second DC bus bar 11 contacts the second partition 70 via the third thermally conductive member 71 . Although FIG. 10 illustrates an example in which the second DC bus bar 11 contacts the second partition wall 70 via the third thermally conductive member 71, the first DC bus bar 10 contacts the third thermally conductive member 71. It is good also as a structure which contacts the 2nd partition 70 through. In this case, the connecting portion between the first DC bus bar 10 and the second DC bus bar 11 is provided closer to the second DC bus bar 11 than the second partition wall 70, and the second partition wall 70 is directly below the first DC bus bar 10. shall be located. The third thermally conductive member 71 is a thermally conductive member such as a heat radiation sheet or heat radiation grease. The second partition wall 70 may be formed integrally with the metal case 7 or may be formed separately from the metal case 7 . The rest of the configuration is the same as the development view of the power converter 1 shown in FIG. 3 of the first embodiment.

FIG. 11 is a top view of the power converter 1 according to the second embodiment. In FIG. 11, an arrow P indicates a heat conduction path of the filter circuit section 20 (the noise elimination capacitor 21 and the noise elimination core 26) with the first DC bus bar 10 and the second DC bus bar 11 removed.

The heat generated by the noise elimination capacitor 21 and the noise elimination core 26 is conducted to the first barrier 60 via the thermally conductive second partition 70, or the heat generated by the filter circuit section 20 is transferred to the noise elimination capacitor 21 and the noise elimination core 26. and the heat is radiated to the coolant flow path 8 .

FIG. 12(A) is a top view of the power conversion device 1 according to the second embodiment, and FIG. 12(B) is a side view of the power conversion device 1 according to the second embodiment. In FIG. 12(A), the heat conduction path of the second DC bus bar 11 is indicated by an arrow Q with the first DC bus bar 10 and the second DC bus bar 11 removed. In FIG. 12(B), the path of heat conduction of the second DC bus bar 11 is indicated by an arrow Q in a state where the first DC bus bar 10 and the second DC bus bar 11 are attached.

As shown in FIGS. 12A and 12B, the heat generated by the second DC bus bar 11 is conducted to the second partition wall 70 via the third thermally conductive member 71, passes through the first partition wall 60, The heat is radiated to the coolant channel 8 . In the case where the first DC bus bar 10 is in contact with the second partition wall 70 via the third thermally conductive member 71, the heat generated by the first DC bus bar 10 is transmitted via the third thermally conductive member 71. The heat is conducted to the second partition 70 and radiated to the coolant channel 8 via the first partition 60 .

[Third Embodiment]
FIG. 13 is a perspective view of the power converter 1 according to the third embodiment. FIG. 14 is an exploded view of the power converter 1 according to the third embodiment. In the third embodiment, in addition to the configuration of the second embodiment, a shield portion 72 is provided on the second partition wall 70 . 1 of the first embodiment, the perspective view of the bottom surface of the power conversion device 1 shown in FIG. 4, the first DC bus bar 10 and the second DC bus bar 10 shown in FIG. A perspective view showing the DC bus bar 11 is the same as in the third embodiment, so the illustration is omitted. Also, the same reference numerals are given to the same parts as in the first embodiment, and the description thereof will be omitted.

As shown in FIGS. 13 and 14, the second partition 70 includes a shield portion 72 standing in the height direction of the second partition 70. The height including the second partition 70 and the shield portion 72 is 1 corresponds to the height up to the surface of the second DC bus bar 11 arranged on the smoothing capacitor portion 51 . Note that the second partition wall 70 may have a height up to the surface of the second DC bus bar 11 arranged on the first smoothing capacitor portion 51 without providing the shield portion 72 .

15A is a top view of the power conversion device 1, and FIG. 15B is a side view of the power conversion device 1. FIG.

As shown in FIG. 15B, the height including the second partition wall 70 and the shield portion 72 corresponds to the height to the surface of the second DC bus bar 11 arranged above the first smoothing capacitor portion 51. do. In FIG. 15B, the height to the surface of the second DC bus bar 11 is slightly higher, but it may be equal to or slightly lower than the height to the surface of the second DC bus bar 11 . The height may be such that a stray capacitance Cb2g, which will be described later, is formed between the shield part 72 and the second DC bus bar 11 .

As shown in FIG. 15A, a stray capacitance Cb2g is formed between the shield portion 72 and the second DC bus bar 11. As shown in FIG. The stray capacitance Cb2g uses the switching operation (voltage change) of the power semiconductor modules 4a, 4b, and 4c as a noise source NS, and causes the generated noise current to flow to the metal case 7 (GND). A noise current I flowing through the stray capacitance Cb2g is represented by the following equation (1).
I=Cb2g*(Δv/Δt) (1)
Here, Δv is the voltage between the shield portion 72 and the second DC bus bar 11, and Δt is the time.

In addition, when the second partition 70 is set to the height up to the surface of the second DC bus bar 11 arranged on the first smoothing capacitor portion 51 without providing the shield portion 72, the second partition 70 and the second DC bus bar 11, a stray capacitance Cb2g is formed.
According to this embodiment, it is possible to suppress the noise current from flowing out from the DC power supply terminal 6 .

According to the embodiment described above, the following effects are obtained.
(1) The power conversion device 1 includes a power semiconductor circuit unit 4 that converts DC power into AC power, a smoothing capacitor 50 that smoothes the DC power, and a power semiconductor circuit unit 4 on the opposite side of the smoothing capacitor 50. and a coolant flow path 8 for cooling the power semiconductor circuit unit 4, the filter circuit unit 20 includes a noise elimination capacitor 21 and a noise elimination core 26, and a smoothing capacitor 50 includes a first smoothing capacitor unit 51 and a second smoothing capacitor unit 52, between the noise elimination capacitor 21 and the noise elimination core 26, and between the first smoothing capacitor unit 51 and the second smoothing capacitor unit 52. A thermally conductive first partition 60 is provided between them, and the first partition 60 is thermally connected to the coolant channel 8 .

The present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are included in the scope of the present invention as long as they do not impair the features of the present invention. be Moreover, it is good also as a structure which combined each above-mentioned embodiment.

DESCRIPTION OF SYMBOLS 1... Power converter, 2... DC power supply, 3... Inverter main circuit, 4... Power semiconductor circuit part, 4a, 4b, 4c... Power semiconductor module, 5... Motor generator , 6... DC power supply terminal, 7... Metal case, 8... Coolant channel, 10... First DC bus bar, 10p... Positive electrode side conductor, 10n... Negative electrode side conductor, 10 m Mold resin material 11 Second DC busbar 11p Positive electrode conductor 11n Negative electrode conductor 11m Mold resin material 12 AC busbar 20 Filter circuit section 21 noise elimination capacitor 22 X capacitor 23, 24 Y capacitor 26 noise elimination core 50 smoothing capacitor 51 first Smoothing capacitor section 52 Second smoothing capacitor section 60 First partition wall 61 First thermal conductive member 62 Second thermal conductive member 70 Second Partition wall 71 Third heat conductive member 72 Shield part.

Claims (7)

a power semiconductor circuit unit that converts DC power to AC power;
a smoothing capacitor for smoothing the DC power;
a filter circuit section disposed on the opposite side of the smoothing capacitor from the power semiconductor circuit section;
a coolant channel for cooling the power semiconductor circuit unit,
The filter circuit section includes a noise elimination capacitor and a noise elimination core,
The smoothing capacitor includes a first smoothing capacitor section and a second smoothing capacitor section,
A thermally conductive first partition is provided between the noise elimination capacitor and the noise elimination core and between the first smoothing capacitor section and the second smoothing capacitor section. A power conversion device thermally connected to the coolant channel. The power converter according to claim 1,
The filter circuit unit includes a first DC bus bar,
The first DC bus bar is connected to the noise elimination capacitor and inserted through the through hole of the noise elimination core,
The power conversion device, wherein the first DC bus bar is in contact with the first partition via a first thermally conductive member. The power converter according to claim 1,
A second DC bus bar connected to the first smoothing capacitor unit and the second smoothing capacitor unit,
The power conversion device, wherein the second DC bus bar is in contact with the first partition via a second thermally conductive member. The power converter according to claim 1,
A power conversion device, wherein a thermally conductive second partition is provided between the filter circuit unit and the smoothing capacitor. The power converter according to claim 4,
The filter circuit unit includes a first DC bus bar,
Further comprising a second DC bus bar connected to the first smoothing capacitor unit and the second smoothing capacitor unit,
The power conversion device, wherein the first DC bus bar or the second DC bus bar is in contact with the second partition via a third thermally conductive member. The power converter according to claim 4,
A second DC bus bar connected to the first smoothing capacitor unit and the second smoothing capacitor unit,
A said 2nd partition is a power converter device which has height corresponded to the height to the surface of said 2nd DC bus-bar arrange|positioned on a said 1st smoothing capacitor part. The power converter according to claim 4,
A second DC bus bar connected to the first smoothing capacitor unit and the second smoothing capacitor unit,
The second partition includes a shield portion erected in the height direction of the second partition, and the height including the second partition and the shield is arranged above the first smoothing capacitor portion. A power conversion device corresponding to the height to the surface of the second DC bus bar.

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