JP6152723B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device that converts power using a semiconductor element.

  A cooling wind tunnel is provided in an apparatus housing of a power conversion circuit including a semiconductor element, a heat radiating part of a cooler is disposed in the cooling wind tunnel, and a forced air is blown to the heat radiating part using an electric blower. A technique for cooling is known (see, for example, Patent Document 1).

JP-A-2005-304151

  In said technique, since the heat | fever of a semiconductor element is transmitted to the thermal radiation part of a cooler and is radiated, the said cooler becomes high temperature with the heat | fever of a semiconductor element. In this case, since the cooler is arranged in contact with the device housing of the power conversion circuit, the device housing also becomes hot due to the heat of the cooler, and the peripheral parts of the device composed of resin material or the like There is a problem that an influence such as deterioration may occur.

  In addition, since there is no structure or the like for absorbing mechanical vibration from outside the apparatus in the apparatus casing, there is a problem that the apparatus may be affected by damage due to the mechanical vibration. is there.

  Problem to be solved by the invention is providing the power converter device which can suppress the influence on the peripheral components by the heat | fever of an apparatus main body, and can suppress the influence by the mechanical vibration from the outside.

The present invention includes a cooling unit including a heat dissipation unit exposed to the outside from a first opening of the first casing in a housing space of the first casing, a cooling unit having a power module, a circuit board, , And the filling material filled in the accommodation space is interposed between the cooling unit and the first casing and between the circuit board and the first casing, respectively. And a second housing embedded in the filler so as to be interposed between the cooling unit and the first housing, and having a second opening. At least a part of is exposed to the outside from the filler through the second opening, thereby solving the above problem.

  According to the present invention, the cooling unit is held in the first casing without directly contacting the first casing. Thereby, since it can suppress that a 1st housing | casing becomes high temperature with the heat of the said cooling unit, the influence on peripheral components by the heat | fever of a power converter device can be suppressed.

  Further, according to the present invention, the filler is interposed between the cooling unit and the first casing and between the circuit board and the first casing, so that the machine is transmitted from the outside. The mechanical vibration is mitigated, and the influence on the power converter by the mechanical vibration can be suppressed.

FIG. 1 is a cross-sectional view showing a power converter according to the first embodiment of the present invention. FIG. 2 is a schematic diagram for explaining the operation of the power conversion device according to the first embodiment of the present invention. FIG. 3 is a graph for explaining the operation of the power conversion device according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view showing a power conversion device according to the second embodiment of the present invention. FIG. 5 is a schematic diagram for explaining the operation of the power conversion device according to the second embodiment of the present invention. 6 (A) and 6 (B) are views showing a first modification of the power conversion device according to the second embodiment of the present invention, FIG. 6 (A) is a plan view, and FIG. 6 (B). FIG. 7 is a cross-sectional view taken along the line VIB-VIB in FIG. FIG. 7: is sectional drawing which shows the 2nd modification of the power converter device in 2nd Embodiment of this invention. FIG. 8 is a cross-sectional view showing another modification of the power conversion device according to the second embodiment of the present invention, and is a view corresponding to a portion VIII in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< first embodiment >>
FIG. 1 is a cross-sectional view showing a power conversion device according to this embodiment.

  The power conversion device 1 in the present embodiment is a device that converts DC power into three-phase AC, and is used, for example, in an electric vehicle. As shown in FIG. 1, the power conversion device 1 includes a first housing 2, a device main body 3 disposed inside the first housing 2, and an interior of the first housing 2. And a filled filler 4.

  As shown in FIG. 1, the first housing 2 is a rectangular housing having a first opening 21 that opens upward in the drawing, and is made of aluminum or the like. A DC connector 22 is attached to the right wall surface 2 </ b> R of the first housing 2, and DC power is supplied from an external DC power source (not shown) via the DC connector 22. Further, an AC connector 23 is attached to the left side surface 2L of the first housing 2, and AC power (three-phase AC) is applied to an external motor (not shown) or the like via the AC connector 23. . The apparatus main body 3 is accommodated in the accommodating space 24 formed inside the first casing 2.

  As shown in FIG. 1, the apparatus body 3 includes a cooling unit 31, a bus bar electrode 32 including a P potential side bus bar electrode 321 and an N potential side bus bar electrode 322, a circuit board 33, a smoothing capacitor 34, and the like. And a second housing 35 to be accommodated.

  The cooling unit 31 includes a power module 311 and a cooler 312 for cooling the power module 311. The power module 311 is mounted with a semiconductor element 311a and the semiconductor element 311a mounted thereon. And a substrate 311d.

  The semiconductor element 311a includes a switching element 311b configured from an insulated gate bipolar transistor (IGBT) and the like, and a diode 311c connected in series with the switching element 311b. The collector terminal of the switching element 311b is connected to the cathode terminal of the diode 311c, and the emitter terminal of the switching element 311b is connected to the anode terminal of the diode 311c. The gate terminal of the switching element 311b is connected to a drive circuit (described later).

  The cooler 312 includes a main body 312a having a power module 311 attached to the lower surface 301, and cooling fins 312b formed on the upper surface 302 of the main body 312a. The heat of the power module 311 transmitted through the main body 312a is dissipated by the cooling fins 312b, whereby the power module 311 can be cooled.

  The main body 312a in the present embodiment corresponds to an example of the main body of the present invention, the upper surface 302 in the present embodiment corresponds to an example of “one surface of the main body” of the present invention, and the lower surface 301 in the present embodiment. Corresponds to an example of the “other surface of the main body” of the present invention, and the cooling fin 312b in the present embodiment corresponds to an example of the heat dissipation unit of the present invention.

  In the present embodiment, three power modules 311 corresponding to each phase of the three-phase AC to be output are arranged at substantially equal intervals on the lower surface 301 of the main body 312a of the cooler 312 and connected in parallel. Has been.

  In this embodiment, as shown in FIG. 1, a P potential electrode 321a is provided on the inner right side surface of the second casing 35, and the lower end of the P potential electrode 321a is connected to the DC connector 22 by a DC cable 321c. Has been. The upper end of the P potential electrode 321a is connected to the switching element 311b of the power module 311 by a bonding wire 321b formed of aluminum or the like. When the power converter 1 is used, the DC connector 22 is connected to a DC power source, and power from the DC power source is supplied to the switching element 311b via the P potential electrode 321a.

  Although not particularly illustrated, an N potential electrode is provided on the back side in FIG. 1 of the P potential electrode 321a, and the N potential electrode is connected to the DC connector 22 and the switching element 311b in the same manner as the P potential electrode 321a. The power of the DC power supply connected to the DC connector 22 can be supplied to the switching element 311b.

  The switching elements 311b of the three power modules 311 are connected to an AC connector by an AC cable (not shown), and can apply a three-phase alternating current to a motor (not shown) connected to the AC connector 23. It has become.

  As shown in FIG. 1, a circuit board 33 provided with a drive circuit 331 is provided at a substantially central portion of the apparatus main body 3 in the present embodiment. The drive circuit 331 is connected to the gate terminal of the switching element 311b, and a gate voltage can be applied from the drive circuit 331 to the gate terminal.

  A P potential side bus bar electrode 321 connected to the P potential electrode 321a is provided above the circuit board 33 in the drawing, and an N potential side bus bar electrode 322 connected to an N potential electrode (not shown). Is provided. The drive circuit 331 acquires power supply power from a DC power supply (not shown) connected to the DC connector 22 via these bus bar electrodes 321 and 322.

  In the present embodiment, as shown in FIG. 1, a smoothing capacitor 34 composed of an electrolytic capacitor or the like is provided at the inner lower portion of the apparatus main body 3, and the smoothing capacitor 34 includes P potential electrodes 321 a and N The semiconductor element 311a is electrically connected through the potential electrode. The smoothing capacitor 34 can smooth the DC voltage supplied from the DC power source connected to the DC connector 22.

  The second casing 35 is a rectangular casing made of aluminum or the like, and accommodates the above-described cooling unit 31, bus bar electrode 32, circuit board 33, and smoothing capacitor 34. A fixing member 351 composed of a bolt or the like is provided inside the second casing 35, and the cooling unit 31 is supported and fixed on the upper part of the second casing 35 by the fixing member 351. Has been. In addition, the bus bar electrode 32 and the circuit board 33 are supported and fixed by the substantially central portion of the second casing 35 by the fixing member 351, and the smoothing capacitor 34 is disposed at the lower portion of the second casing 35. It is fixed.

  Further, as shown in FIG. 1, a second opening 352 that opens toward the upper side in the drawing is formed in the upper portion of the second casing 35, and the second opening 352 and the first casing are formed. The cooling fin 312b of the cooler 312 is exposed to the outside through the first opening 21 of the body 2.

  In the present embodiment, as shown in FIG. 1, the filling material 4 is filled in the accommodation space 24 of the first housing 2. The filler 4 is made of a flexible material that is excellent in electrical insulation, heat insulation, and heat resistance and has a lower elastic modulus than that of the first housing 2. Examples of such materials include resin materials such as silicone potting agents and gel materials such as silicone gel.

  With this filler 4, the second casing 35 of the apparatus main body 3 is held in the housing space 24 in a non-contact state with the first casing 2. In addition, the inside of the second housing 35 is also filled with the filler 4, and the cooling unit 31, the bus bar electrode 32, the circuit board 33, and the smoothing capacitor 34 are buried in the filler 4. .

  Next, the operation in this embodiment will be described. FIG. 2 is a schematic diagram for explaining the operation of the power conversion device according to this embodiment, and FIG. 3 is a graph for explaining the operation of the power conversion device according to this embodiment.

  As shown in FIG. 2, the power conversion device 1 according to the present embodiment has the device main body 3 held inside the accommodation space 24 formed in the first housing 2 via the filler 4. For this reason, the mechanical vibration from the outside of the apparatus transmitted to the apparatus main body 3 is reduced by the effect of the elasticity and the damping coefficient C of the filler 4. Thereby, it can suppress that the power converter device 1 provided with the apparatus main body part 3 and the said apparatus main body part 3 receives influence, such as a damage, by the said mechanical vibration. Moreover, since it is not necessary to provide the power converter 1 with the reinforcement member for strengthening the tolerance with respect to a mechanical vibration, the enlargement and cost increase of the said power converter 1 can be suppressed.

  In the schematic diagram shown in FIG. 2, when mechanical vibration is applied from a support member 5 such as a vehicle on which the power conversion device 1 is mounted, the device main body 3 that is transmitted through the filler 4 is transmitted to the device main body 3. The vibration transmission rate T of the mechanical vibration is expressed by the following equation (1).

T = 1 / | 1- (f / f _n ) ² | (1)
However, in the above formula (1), f is the frequency of the mechanical vibration transmitted from the support member 5, and f _n is the natural frequency of the filler 4. Here, the natural frequency f _n of the filler 4 is expressed by the following equation (2).

ただし、上記（２）式において、ｋは充填材４の弾性を示すバネ定数であり、ｍは装置本体部３及び当該装置本体部３の内部に充填された充填材４の質量であり、ａは定数である。

However, in the above equation (2), k is a spring constant indicating the elasticity of the filler 4, m is the mass of the apparatus main body 3 and the filler 4 filled in the apparatus main body 3, and a Is a constant.

  In this case, when the vibration transmission rate T is 1 or less, that is, in the shaded area (anti-vibration effect area) of FIG. 3 showing the above equation (1) as a graph, the transmission of the mechanical vibration is suppressed. It is known that the effect is improved.

For this reason, by using the filler 4 having the spring constant k satisfying the following expression (3), the transmission of mechanical vibration to the apparatus main body 3 is further reduced, and the power converter 1 due to the mechanical vibration is transmitted. Can be further suppressed.

Further, in the power conversion layer value 1 in the present embodiment, the bus bar electrodes 321 and 322 are provided in the substantially central portion of the apparatus main body 3. Thereby, the m value in the above equation (2) increases, and the natural frequency f _n of the filler 4 becomes relatively small. For this reason, the area | region (vibration-proof effect area | region) of the frequency f which satisfy | fills said (3) Formula spreads, and the influence on the power converter device 1 by a mechanical vibration can be suppressed further.

The cooling fin 312 b of the cooler 312 is exposed to the outside through the first opening 21 of the first housing 2 and the second opening 352 of the second housing 35. As a result, the thermal resistance R ₀ from the cooling fin 312b to the outside air does not deteriorate, and sufficient cooling performance in the cooler 312 can be ensured.

  Further, the thermal resistance R ′ between the first casing 2 and the second casing 35 is greater than the thermal resistance of the first or second casing 2, 35 due to the interposition of the filler 4. It is relatively large. Thereby, it can suppress effectively that the heat | fever of the power module 311 in the apparatus main body part 3 is transmitted to the 1st housing | casing 2, and can suppress the influence on peripheral components by the heat | fever of the power converter device 1. FIG.

<< Second Embodiment >>
FIG. 4 is a cross-sectional view showing the power conversion device according to the second embodiment, and FIG. 5 is a schematic view for explaining the operation of the power conversion device according to the second embodiment. FIG. 7B is a diagram illustrating a first modification of the power conversion device according to the second embodiment, and FIG. 7 is a cross-sectional view illustrating a second modification of the power conversion device according to the second embodiment. The power conversion device 1B according to the second embodiment is the same as the first embodiment described above except that the device main body 3B is different. Therefore, only the parts different from the first embodiment will be described, and the first embodiment will be described. The same reference numerals are given and description thereof is omitted.

  As shown in FIG. 4, the apparatus main body 3B includes a cooling unit 31, a circuit board 33, a smoothing capacitor 34, a second casing 35B, and a filling filled in the second casing 35B. And a material 4B.

  The second casing 35B is a rectangular casing formed of aluminum or the like, and the end portion 350 of the second casing 35B is exposed to the outside. The inside of the second casing 35B is filled with a filler 4B, and the cooling unit 31 is embedded and held in the filler 4B.

  Further, as shown in FIG. 4, a gap 353 is provided between the cooling unit 31 and the second opening 352 of the second casing 35B. Thereby, the cooling unit 31 is held in a non-contact state with the second casing 35B.

  The filler 4B is excellent in electrical insulation, heat insulation, and heat resistance, and is formed of a flexible material having a lower elastic modulus than that of the first housing 2, and the filler 4 described in the first embodiment It is comprised from the same material.

  The cooling fins 312b of the cooler 312 are exposed to the outside from the second opening 352 provided in the upper part of the second casing 35B in the drawing and the first opening 21 of the first casing 2. Thereby, the heat of the power module 311 transmitted through the main body 312a of the cooler 312 can be dissipated from the cooling fin 312b, and the power module 311 can be cooled.

  As shown in FIG. 4, a smoothing capacitor 34 is attached to the outside of the bottom surface of the second housing 35 </ b> B in the present embodiment, and a circuit board 33 is attached to the lower part of the smoothing capacitor 34. The smoothing capacitor 34 and the circuit board 33 are both embedded and held in the filler 4. The circuit board 33 may be directly fixed and attached to the second casing 35B.

As shown in FIG. 5, the power converter 1 </ b> B according to the present embodiment also holds the device main body 3 </ b> B via the filler 4 in the accommodation space 24 of the first housing 2. Therefore, mechanical vibration transmitted to the power converter 1B is mitigated by the elastic and damping coefficient C ₁ of the effects possessed by the filler 4, it is possible to suppress the influence of the mechanical vibration to the apparatus main body 3B.

Further, the inside of the second casing 35B is filled with a filler 4B, and the apparatus main body 3B is held via the filler 4B. Therefore, mechanical vibrations from the outside of the apparatus is further reduced by the elasticity and the effect of the damping coefficient C ₂ included in the filler 4B, it is possible to further suppress the influence of the mechanical vibration to the apparatus main body 3B.

In addition, as shown in FIG. 5, the power conversion device 1 </ b> B according to the present embodiment also includes the equation (3) described in the first embodiment between the first housing 2 and the second housing 35 </ b> B. By using the filler 4 having the spring constant k ₁ that satisfies the same relationship, the influence on the power conversion device 1B due to mechanical vibration can be effectively suppressed.

Furthermore, in the present embodiment, even in between the cooling unit 31 and the second housing 35B, by using a filler 4B having a spring constant k ₂ satisfying the same relationship as equation (3), vehicle or the like Can be further suppressed from being transmitted to the power module 311. Thereby, the influence to the power converter device 1B by the said mechanical vibration can be suppressed significantly.

Also in the present embodiment, the cooling fin 312b of the cooler 312 is exposed to the outside through the first opening 21 of the first housing 2 and the second opening 352 of the second housing 35B. Yes. As a result, the thermal resistance R ₀ from the cooling fin 312b to the outside air does not deteriorate, and sufficient cooling performance in the cooler 312 can be ensured. Furthermore, since there is no possibility that the thermal resistance R ₁ extending from the end portion 350 of the second housing 35B to the outside air even worse, can be performed more effectively cool the power module 311.

  The thermal resistance R ′ between the first casing 2 and the second casing 35B is relatively greater than the thermal resistance of the first and second casings 2 and 35B due to the interposition of the filler 4. It is getting bigger. Further, in the present embodiment, the cooling unit 31 is held in the second casing 35B in a non-contact state. For this reason, due to the filler 4B interposed in the gap 353, the thermal resistance R ″ between the second casing 35B and the cooling unit 31 is also greater than the thermal resistance of the first and second casings 2 and 35B. It is relatively large. As a result, it is possible to further suppress the heat of the power module 311 from being transmitted to the first housing 2, and it is possible to further suppress the influence on peripheral components due to the heat transmitted from the power conversion device 1B.

  In the present embodiment, in addition to the second casing 35B and the cooling unit 31 being held in a non-contact state, the smoothing capacitor 34 and the circuit board 33 include the second casing 35B. Are provided outside the bottom surface (outside the bottom surface) far from the cooling unit 31. In addition, a filler 4 </ b> B is interposed between the smoothing capacitor 34, the circuit board 33, and the cooling unit 31. As a result, the heat of the power module 311 in the cooling unit 31 can be reduced from being transmitted to the smoothing capacitor 34 and the circuit board 33, and the life reduction of the smoothing capacitor 34 and the circuit board 33 can be suppressed. .

  In this embodiment, as shown in FIGS. 6A and 6B, the second casing is formed so that the mesh member 354 formed of a heat-resistant material or the like covers the second opening 352. The cooling fins 312b of the cooler 312 may be inserted into the mesh of the mesh member 354.

In this case, it is possible to prevent the cooling unit 31 from being peeled off and dropped off from the power conversion device 1B due to mechanical vibration from the outside, and the elasticity (spring) of the filler 4B due to the presence of the mesh member 354. The constant k ₁ ) can be made smaller. Thereby, the effect which suppresses transmission of the mechanical vibration from the outside can be heightened more, and the influence on the power converter device 1B due to the mechanical vibration can be further suppressed.

In the present embodiment, as shown in FIG. 7, the bus bar electrode 32B may be provided on the side surface and the bottom surface of the second casing 35B. In this case, the mass m of the entire apparatus main body 3B increases due to the presence of the bus bar electrode 32B. For this reason, the natural frequency f _n of the filler 4 is reduced (see the above formula (2)), and the region of the frequency f satisfying the above formula (3) (antivibration effect region) is widened. The influence on the power conversion device 1B can be further reduced.

  In this case, the heat dissipation from the end portion 350 of the second housing 35B is further improved due to the high thermal conductivity of the bus bar electrode 32B. Thereby, the influence on peripheral components by the heat transmitted from the power converter device 1B can be further suppressed.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, as shown in FIG. 8, a first tapered shape 355 having a small diameter at the periphery of the second opening 352 toward the outside (upper side in the drawing) of the second housing 35 </ b> B may be provided. In addition, the main body 312a of the cooler 312 is disposed on the inner side (lower side in the drawing) of the second housing 35B, and the second taper facing the first taper shape 355 on the side of the main body 312a. A shape 313 may be provided.

  In this case, the left and right mechanical vibrations received by the power conversion device 1B are caused by the presence of the tapered shapes 355 and 313 as a force toward the inner side (lower side in the drawing) of the second casing 35B. To communicate. As a result, in addition to the above-described effects (the effect of suppressing the influence on peripheral components due to heat transfer and the effect of suppressing the effect of external mechanical vibration), the cooling unit 31 is removed from the power converter 1B by the mechanical vibration. The effect which prevents peeling and dropping off can be produced.

DESCRIPTION OF SYMBOLS 1, 1B ... Power converter 2 ... 1st housing | casing 21 ... 1st opening 24 ... Accommodating space 3, 3B ... Apparatus main-body part 31 ... Cooling unit 331 ... Power module 331a ... Semiconductor element 312 ... Cooler 312a ... Main body
301 ... bottom surface
302 ... upper surface 312b ... cooling fin 313 ... second taper shape 32, 32B ... bus bar electrode 321 ... P potential side bus bar electrode 322 ... N potential side bus bar electrode 33 ... Circuit board 331 ... Drive circuit 34 ... Smoothing capacitor 35, 35B ... Second housing 352 ... Second opening 354 ... Reticulated member 355 ... First taper shape 4, 4B ... Filler

Claims (6)

A cooling unit including a main body and a cooler including a heat dissipating part provided on one surface of the main body, and a power module attached to the other surface of the main body and including at least a semiconductor element;
A circuit board on which a driving circuit for driving the semiconductor element is mounted;
A first housing having a first opening and having an accommodating space for accommodating the cooling unit and the circuit board;
A filler filled in the accommodation space,
The cooling unit is embedded in the filler, and the filler is interposed between the first casing and the cooling unit;
The circuit board is also embedded in the filler, and the filler is interposed between the first casing and the circuit board,
At least a part of the heat dissipation part is exposed to the outside from the filler through the first opening ,
A second housing embedded in the filler so as to have a second opening and be interposed between the cooling unit and the first housing;
At least a part of the heat radiating part is exposed to the outside from the filler through the second opening . The power conversion device according to claim 1 ,
The circuit board is directly or indirectly fixed to the second casing, and the power conversion device is characterized in that: The power conversion device according to claim 1 or 2 ,
A power converter, further comprising a smoothing capacitor electrically connected to the semiconductor element and fixed to the second housing. A power converter according to any one of claims 1 to 3,
The power conversion device further comprising a bus bar electrode provided on a side surface of the second casing. The power conversion device according to any one of claims 1 to 4 , wherein:
A mesh member attached to the second housing so as to cover the second opening;
The heat radiating unit is inserted into a mesh of the mesh member. The power conversion device according to any one of claims 1 to 5 ,
The peripheral edge of the second opening has a first taper shape having a small diameter toward the outside of the second housing,
The power converter according to claim 1, wherein the main body has a second tapered shape that is disposed inside the second housing and faces the first tapered shape.

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