JP5808789B2 - Power converter - Google Patents

Description

  The present invention relates to an in-vehicle power conversion device mounted on an automobile or the like, and more particularly to a power conversion device including a semiconductor switching element constituting a power conversion unit such as an inverter.

  Conventionally, in a vehicle such as an electric vehicle, DC power from a battery is converted into predetermined AC power by a power conversion unit such as an inverter and supplied to a motor, and power conversion is performed in accordance with an accelerator operation or the like by a vehicle driver. The output torque of the motor is controlled by controlling the switching operation of the semiconductor switching elements constituting the unit. The switching operation of the power conversion unit is controlled by controlling the generation timing of the gate signal applied to the semiconductor switching element by the control circuit unit.

  In order to control the switching operation of the power conversion unit, it is necessary to suppress the pulsation of the DC voltage or the DC current supplied to the power conversion unit. Usually, these pulsations are performed using a large capacity smoothing capacitor. Is suppressed. As the large-capacity smoothing capacitor, an aluminum electrolytic capacitor or a film capacitor that can easily obtain a large capacitance is generally used. Conventionally, as a power converter for further reducing noise or vibration generated by pulsation of a DC voltage or DC current supplied to a power converter, a film is wound with a strong tension as a large-capacity smoothing capacitor. A power converter using a formed cylindrical film capacitor and utilizing the characteristics of the cylindrical film capacitor is known (for example, see Patent Document 1).

JP 2006-304410 A

  However, since a necessary capacitance is secured by connecting a plurality of cylindrical film capacitors in parallel, noise or vibration due to pulsation of DC voltage or DC current supplied to the power converter is reduced, but in parallel. There is a problem in that a dead space between a plurality of connected cylindrically wound film capacitors is increased, and the power converter is increased in size.

  The present invention provides a power converter that can reduce noise or vibration propagating to the outside and can be miniaturized.

The power conversion device according to the present invention includes a switching element, suppresses fluctuations in DC power supplied to the switching element, a power conversion unit that performs power conversion between direct current and alternating current by switching operation of the switching element. A smoothing capacitor, a case for housing the switching element and the smoothing capacitor, a cover provided on the case and covering the switching element and the smoothing capacitor, and a first vibration isolation member provided between the smoothing capacitor and the cover The first vibration isolation member is made of a foam using rubber or a foam using resin.

  According to the power conversion device of the present invention, the vibration or noise generated in the smoothing capacitor is absorbed by the first vibration isolation member, and the air propagation to the cover of the noise generated in the smoothing capacitor is the first vibration isolation. Since it reduces by a member, the vibration or noise which propagates outside the power converter device can be reduced. Moreover, since vibration or noise propagating to the outside of the power converter is reduced without using a cylindrical film capacitor, the power converter can be downsized.

It is a block diagram which shows the power converter device which concerns on Embodiment 1 of this invention. It is a block diagram which shows the modification of the power converter device of FIG. It is a block diagram which shows the power converter device which concerns on Embodiment 2 of this invention. It is a block diagram which shows the power converter device in the state in which the movement control part of FIG. 3 and the 1st anti-vibration member are not provided.

Embodiment 1 FIG.
1 is a block diagram showing a power conversion apparatus according to Embodiment 1 of the present invention. In the figure, the power converter includes a case 1, a switching power module 2 accommodated in the case 1, a cooling member 3 fixed to the bottom surface of the case 1 from the back side, and a smoothing capacitor 4 accommodated in the case 1. The cover 5 is provided on the case 1 and covers the switching power module 2 and the smoothing capacitor 4.

  The switching power module 2 has a switching element and a free wheel diode. Moreover, the switching power module 2 is modularized by resin-sealing a switching element and a free wheel diode. In this example, the power conversion device includes six switching power modules 2. The six switching power modules 2 constitute a positive arm and a negative arm of each phase in a power converter (not shown) such as an inverter composed of a three-phase bridge circuit. That is, the six switching power modules 2 constitute a power conversion unit.

  The cooling member 3 is fixed to the case 1 with a part of the cooling member 3 in contact with the bottom surface of the case 1. The cooling member 3 includes a cooling member main body 31 that contacts the case 1, and cooling fins 32 that are provided on the cooling member main body 31 and extend from the cooling member main body 31 in a direction away from the case 1. The six switching power modules 2 are fixed to the case 1 in contact with the cooling member main body 31. Further, the six switching power modules 2 are arranged inside the case 1. Heat generated in the switching power module 2 is transmitted to the cooling member main body 31 and released into the atmosphere via the cooling fins 32.

  The smoothing capacitor 4 is composed of a flat wound film capacitor. The smoothing capacitor 4 is disposed inside the case 1. The power converter further includes a smoothing capacitor fixing screw 6 for fixing the smoothing capacitor 4 to the case 1. The smoothing capacitor fixing screw 6 is attached to the case 1. The smoothing capacitor fixing screw 6 may be attached to the cooling member 3 through the case 1. The smoothing capacitor 4 is provided to suppress pulsation of a DC voltage or a DC current supplied to the power conversion unit. Therefore, a plurality of smoothing capacitors 4 are provided in order to ensure a necessary capacitance, and these are connected in parallel. The plurality of smoothing capacitors 4 connected in parallel are connected between the DC terminals of the power converter. Although not shown, the plurality of smoothing capacitors 4 are fixed to the case 1 in a state of being juxtaposed adjacent to each other.

  The switching power module 2 has a DC side input terminal 21 and an AC side input terminal 22. The power converter further includes a terminal fixing screw 7 for fixing the DC side input terminal 21 to the case 1 and a terminal fixing screw 8 for fixing the AC side input terminal 22 to the case 1. The DC side input terminal 21 is fixed to the case 1 using the terminal fixing screw 7 together with one terminal 41 of the smoothing capacitor 4. The DC input terminal 21 of the switching power module 2 and the terminal 41 of the smoothing capacitor 4 are electrically connected to each other, and further electrically connected to a main power source (not shown) such as a battery. . The AC side input terminal 22 of the switching power module 2 is connected to a motor (not shown) of the vehicle.

  The cover 5 protects the plurality of smoothing capacitors 4 and the six switching power modules 2 from foreign matter and condensation. A concave portion 51 is formed in the portion of the cover 5 that faces the smoothing capacitor 4. The shape of the recess 51 is such that the gap between the upper surface (surface) and the side surface of the smoothing capacitor 4 and the inner surface of the recess 51 is small. The upper surface of the smoothing capacitor 4 is a surface located on the side opposite to the surface (bottom surface) of the smoothing capacitor 4 facing the bottom surface of the case 1. The power conversion device further includes a sheet-like first vibration isolation member 9 provided between the upper surface of the smoothing capacitor 4 and the recess 51. The area of the first vibration isolation member 9 is equal to the area of the bottom surface of the recess 51. Therefore, the first vibration isolation member 9 is attached to the recess 51 to be positioned in the recess 51, and the position of the first vibration isolation member 9 with respect to the cover 5 is determined. The first vibration isolating member 9 is inserted between the upper surface of the smoothing capacitor 4 and the bottom surface portion of the recess 51 in a pressure contact state.

  Next, an assembly procedure of the power conversion device will be described. First, the smoothing capacitor 4 and the switching power module 2 are housed in the case 1, and the smoothing capacitor 4 and the switching power module 2 are installed in the case 1 using the smoothing capacitor fixing screw 6, the terminal fixing screw 7 and the terminal fixing screw 8. Secure to.

  Thereafter, the cover 5 is assembled to the case 1 with the first vibration isolation member 9 attached to the recess 51. By assembling the cover 5 to the case 1 with the first vibration isolation member 9 positioned by the recess 51, the first vibration isolation member 9 is pressed against the smoothing capacitor 4. The assembly procedure of the power conversion device is thus completed.

  As described above, according to the power conversion device according to the first embodiment of the present invention, vibration or noise generated in the smoothing capacitor 4 is absorbed by the first vibration isolation member 9, and the smoothing capacitor 4 Since the air propagation to the cover 5 of the generated noise is reduced by the first vibration isolation member 9, vibration or noise propagating to the outside of the power converter can be reduced. Moreover, since vibration or noise propagating to the outside of the power converter is reduced without using a cylindrical film capacitor, the power converter can be downsized.

  Further, the cover 5 is formed with a recess 51, and the first vibration isolation member 9 is pressed against the smoothing capacitor 4 by assembling the cover 5 to the case 1 with the first vibration isolation member 9 positioned by the recess 51. Therefore, the insertion position of the first vibration isolation member 9 can be restricted to a predetermined position, and vibration or noise propagating to the outside of the power conversion device can be greatly reduced without changing the external size of the power conversion device. Can be reduced.

  In addition, when the first vibration isolation member 9 is not positioned, the position of the first vibration isolation member 9 may change due to expansion / contraction such as a heat cycle, which may reduce the sound insulation performance. According to the power conversion device according to the first embodiment of the invention, the size of the first vibration isolation member 9 is made equal to the area of the bottom surface of the recess 51 corresponding to the shape of the smoothing capacitor 4, Since the shape is such that the gap between the upper surface and the side surface of the smoothing capacitor 4 is small, there is no gap that can move with respect to the size of the first vibration isolation member 9, and the first vibration isolation Even if expansion and contraction such as a heat cycle occurs in the member 9, it is possible to prevent the first vibration isolation member 9 from being displaced from the insertion position, and it is possible to maintain sound insulation performance.

  Moreover, the sound insulation performance can be arbitrarily controlled by arbitrarily changing the type and insertion range of the first vibration isolation member 9. For example, in order to improve the sound insulation performance, a foam such as rubber or resin may be used as the first vibration isolation member 9. If the first vibration isolator 9 is not in close contact with the smoothing capacitor 4, the sound insulation effect will be reduced, but foams such as rubber or resin can be compressed with very little force, Since the cover 5 can be easily brought into close contact with each other without being deformed and is extremely excellent in soundproofing and vibration-proofing properties, a great sound insulation performance can be obtained.

  Further, since the smoothing capacitor 4 is composed of a flat wound film capacitor, a dead space due to the juxtaposition of the plurality of smoothing capacitors 4 is reduced, and a small, low noise or low vibration power converter can be obtained. .

  In the first embodiment, the configuration in which the case 1 and the cooling member 3 are in contact with each other has been described. However, propagation of vibration and noise generated in the smoothing capacitor 4 to the cooling member 3 via the case 1 is reduced. In such a case, a second vibration isolation member 10 may be inserted between the case 1 and the cooling member 3 as shown in FIG. Thereby, the vibration and noise propagated from the smoothing capacitor 4 to the case 1 are absorbed by the second vibration isolation member 10, and the vibration or noise propagated to the outside of the power converter can be greatly reduced. As a material constituting the second vibration isolating member 10, as in the first vibration isolating member 9, foams such as rubber or resin can be cited.

  In the first embodiment, the configuration in which the concave portion 51 into which the first vibration isolation member 9 is inserted is formed in the cover 5 is described. However, the concave portion into which the first vibration isolation member 9 is inserted is the smoothing capacitor 4. The structure formed in this may be sufficient. Even in this case, the first vibration isolation member 9 is positioned by the recess.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing a power conversion apparatus according to Embodiment 2 of the present invention. In the figure, the power conversion device further includes a movement restricting portion 11 provided on the cover 5. Unlike the first embodiment, the cover 5 is not formed with the recess 51 (FIG. 1). The movement restricting portion 11 is formed to correspond to the outer peripheral shape on the upper surface of the smoothing capacitor 4. In other words, the shape of the movement restricting portion 11 has a slight gap between the upper surface of the smoothing capacitor 4 and the cover 5 and a slight gap between the inner peripheral surface of the movement restricting portion 11 and the side surface of the smoothing capacitor 4. It has a shape like this. The area of the first vibration isolation member 9 is equal to the area when the space defined by the movement restricting portion 11 is viewed in the height direction. Therefore, the first vibration isolating member 9 is attached to the movement restricting portion 11 to be positioned by the movement restricting portion 11, and the position of the first vibration isolating member 9 with respect to the cover 5 is determined. The first vibration isolation member 9 is inserted between the upper surface of the smoothing capacitor 4 and the portion of the cover 5 facing the upper surface of the smoothing capacitor 4 in a pressure contact state. Other configurations are the same as those in the first embodiment.

  Next, an assembly procedure of the power conversion device will be described. First, the smoothing capacitor 4 and the switching power module 2 are housed in the case 1, and the smoothing capacitor 4 and the switching power module 2 are installed in the case 1 using the smoothing capacitor fixing screw 6, the terminal fixing screw 7 and the terminal fixing screw 8. Secure to.

  Thereafter, the cover 5 is assembled to the case 1 with the first vibration isolation member 9 attached to the movement restricting portion 11. By assembling the cover 5 to the case 1 with the first vibration isolation member 9 positioned by the movement restricting portion 11, the first vibration isolation member 9 is pressed against the smoothing capacitor 4. The assembly procedure of the power conversion device is thus completed.

  As described above, according to the power conversion device of the second embodiment of the present invention, the vibration or noise generated in the smoothing capacitor 4 is absorbed by the first vibration isolation member 9 as in the first embodiment. Moreover, since the air propagation to the cover 5 of noise generated in the smoothing capacitor 4 is reduced by the first vibration isolation member 9, vibration or noise propagating to the outside of the power converter can be reduced, Since vibration or noise propagating to the outside of the power conversion device is reduced without using a cylindrical film capacitor, the power conversion device can be downsized.

  The power conversion device further includes a movement restricting portion 11 provided on the cover 5 and restricting the movement of the first vibration isolating member 9 relative to the cover 5, and the first vibration isolating member 9 is positioned by the movement restricting portion 11. Since the first vibration isolation member 9 is pressed against the smoothing capacitor 4 by assembling the cover 5 to the case 1 in this state, the insertion position of the first vibration isolation member 9 can be restricted to a predetermined position. Further, vibration or noise propagating to the outside of the power converter can be greatly reduced. In particular, by making the area of the first vibration isolation member 9 the minimum area necessary for the sound insulation performance, the cost increase required for noise countermeasures can be further minimized.

  Further, in the power conversion device shown in FIG. 4, vibration or noise propagating to the outside of the power conversion device can be reduced simply by attaching the movement restricting portion 11 to the cover 5 and attaching the first vibration isolation member 9 to the movement restricting portion 11. Therefore, it is possible to minimize the increase in cost required for noise countermeasures without changing the external size of the power conversion device.

  In addition, when the first vibration isolation member 9 is not positioned, the position of the first vibration isolation member 9 may be changed due to expansion due to a heat cycle or the like, and the sound insulation performance may be reduced. According to the power conversion device according to the second embodiment of the present invention, the first vibration isolation device is provided with the movement restricting portion 11 provided on the cover 5 for restricting the position of the first vibration isolation member 9. Even when the member 9 is stretched due to a heat cycle or the like, the first vibration isolation member 9 can be prevented from being displaced from the insertion position, and the sound insulation performance can be maintained.

  Similarly to the first embodiment, the sound insulation performance can be arbitrarily controlled by arbitrarily changing the type and insertion range of the first vibration isolation member 9. For example, in order to improve the sound insulation performance, a foam such as rubber or resin may be used as the first vibration isolation member 9. If the first vibration isolating member 9 is not in close contact with the smoothing capacitor 4, the sound insulation effect is diminished, but foams such as rubber or resin can be compressed with a very small force. Each of them can be easily brought into close contact with each other without being deformed, and since they are very excellent in soundproofing and vibrationproofing, a great sound insulation performance can be obtained.

  Further, as in the first embodiment, since a flat wound film capacitor is used as the smoothing capacitor 4, there is little dead space due to the juxtaposition of the plurality of smoothing capacitors 4, and the power conversion is small and has low noise or vibration. A device can be obtained.

  In the second embodiment, the configuration in which the case 1 and the cooling member 3 are in contact with each other has been described. However, propagation of vibration and noise generated in the smoothing capacitor 4 to the cooling member 3 via the case 1 is reduced. In the case of making it, the second vibration isolation member 10 (FIG. 2) may be inserted between the case 1 and the cooling member 3 as in the first embodiment. Thereby, the vibration and noise propagated from the smoothing capacitor 4 to the case 1 are absorbed by the second vibration isolation member 10, and the vibration or noise propagated to the outside of the power converter can be greatly reduced. As a material constituting the second vibration isolating member 10, as in the first vibration isolating member 9, foams such as rubber or resin can be cited.

  In the second embodiment, the configuration in which the movement restricting portion 11 is provided in the cover 5 has been described. However, the movement restricting portion 11 may be provided in the smoothing capacitor 4. Even in this case, the first vibration isolation member 9 is positioned by the movement restricting portion 11.

  1 Case, 2 Switching Power Module, 3 Cooling Member, 4 Smoothing Capacitor, 5 Cover, 6 Smoothing Capacitor Fixing Screw, 7 Terminal Fixing Screw, 8 Terminal Fixing Screw, 9 First Vibration Isolation Member, 10 Second Vibration Isolation Member , 11 Movement restricting part, 21 DC side input terminal, 22 AC side input terminal, 31 cooling member body, 32 cooling fin, 41 terminal, 51 recess.

Claims (5)

A power conversion unit having a switching element and performing power conversion between direct current and alternating current by a switching operation of the switching element;
A smoothing capacitor that suppresses fluctuations in DC power supplied to the switching element;
A case housing the switching element and the smoothing capacitor;
A cover provided on the case and covering the switching element and the smoothing capacitor;
A first vibration isolating member provided between the smoothing capacitor and the cover;
The first vibration isolating member is made of a foam using rubber or a foam using a resin. In the portion of the cover corresponding to the smoothing capacitor, a recess corresponding to the shape of the smoothing capacitor is formed,
2. The first vibration isolation member is pressed against the smoothing capacitor by assembling the cover to the case in a state where the first vibration isolation member is positioned by the recess. Power converter. A movement restricting portion that is provided on the cover and restricts movement of the first vibration isolation member relative to the cover;
2. The first vibration isolation member is pressed against the smoothing capacitor by assembling the cover to the case in a state where the first vibration isolation member is positioned by the movement restricting portion. The power converter device described in 1.   The power conversion according to any one of claims 1 to 3, further comprising a second vibration isolation member provided between the case and a cooling member that cools the switching element. apparatus.   The said smoothing capacitor is comprised from the flat wound film capacitor, The power converter device as described in any one of Claim 1 to 4 characterized by the above-mentioned.

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