JP2016093072A - Semiconductor power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor power converter which achieves downsizing while inhibiting thermal interference between semiconductor modules on a heat sink.SOLUTION: A semiconductor power converter includes: first semiconductor modules 20A to 20C including first semiconductor elements and configured to conduct power conversion; second semiconductor modules 30A to 30C including second semiconductor elements having usage temperatures higher than the first semiconductor elements and configured to conduct power conversion; and a heat sink 40 having a mounting surface 41, on which the first semiconductor modules and the second semiconductor modules are mounted, and a cooling air passage 44. The heat sink 40 has: at least a first mounting surface 45, on which the first semiconductor modules formed at the upstream side of the cooling air passage 44 are mounted, a second mounting surface 46, on which the second semiconductor modules formed at the downstream side of the cooling air passage 44 are mounted, and a slit 47 formed between the first mounting surface and the second mounting surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a semiconductor power conversion device including a heat sink that cools a plurality of semiconductor modules.

In a semiconductor power conversion device such as an inverter, the semiconductor elements constituting the power conversion device generate heat. Therefore, in order to efficiently cool the semiconductor elements, the semiconductor elements are arranged on a heat sink. Yes.
For example, as shown in FIG. 9, an inverter device that outputs AC power having a set frequency and voltage from a commercial AC power source to an AC load is known as a typical device as a conventional power converter.

  The inverter device includes, for example, a diode rectifier 200 that converts a three-phase alternating current supplied from a three-phase commercial alternating-current power supply 100 into a direct-current voltage, a capacitor 300 that smoothes the direct-current voltage output from the diode rectifier 200, And an inverter circuit 400 that converts the DC voltage smoothed by the capacitor 300 into three-phase AC. Then, the three-phase AC output from the inverter circuit 400 is supplied to an AC load 500 such as a three-phase AC motor or a brushless motor.

Here, the diode rectifier 200 has a configuration in which three sets of diode arms 202A to 202C in which two diodes 201 are connected in series are connected in parallel, and the connection midpoint of each of the diode arms 202A to 202C is each of the commercial AC power supplies 100. Connected to the phase.
Further, the inverter circuit 400 has a configuration in which three sets of switching arms 404A to 404C in which two sets of parallel circuits 403 of a diode switching element 401 and a diode 402 connected in antiparallel thereto are connected in series. The midpoint of connection of the switching arms 404A to 404C is connected to the AC load 500.

A semiconductor element such as a semiconductor switching element or a diode constituting such an inverter device needs to be arranged on a heat sink in order to suppress a temperature rise due to its own loss (steady loss or switching loss).
When cooling a diode rectifier having a diode with low generation loss and an inverter circuit having a semiconductor switching element with high generation loss, for example, as shown in FIG. 10, a semiconductor in which diode arms 202A to 202C of a diode rectifier 200 are modularized. The modules 203A to 203C and the semiconductor modules 405A to 405C obtained by modularizing the switching arms 404A to 404C of the inverter circuit 400 are mounted on the heat sinks 600 and 601 having different thermal resistances, and the heat sinks are disposed upstream of the ventilation path by the cooling fan. The temperature gradient is reduced by arranging 600 and a heat sink 601 on the downstream side (see, for example, Patent Document 1).

  11A to 11C, grooves 702 are formed in the heat sink base plate 701 to reduce thermal interference between the semiconductor modules 700, and auxiliary fins 703 are provided on both sides of the grooves 702. The interval between the semiconductor modules 700 is also reduced (for example, see Patent Document 2).

JP 2003-259658 A JP 2008-206252 A

However, as a semiconductor module constituting the semiconductor power conversion device, it is common to use a switching element such as an IGBT formed of a silicon semiconductor. The maximum operating temperature of the silicon semiconductor junction is set to about 125 ° C. to 150 ° C.
On the other hand, a wide band gap semiconductor formed of silicon carbide (SiC), a gallium nitride-based material, or a semiconductor such as diamond can have a maximum operating temperature of 200 ° C. or higher.

Therefore, as described in Patent Document 1, a diode rectifier with low generation loss uses a silicon semiconductor module, and an inverter circuit with high generation loss uses a wide bandgap semiconductor, and has the highest junction. It is necessary to set the heat resistance of the heat sink so as not to exceed the operating temperature.
When semiconductor modules with different maximum operating temperatures are placed on the heat sink, the heat resistance of the heat sink is set according to the silicon semiconductor with the lowest maximum operating temperature. The area is used at a low temperature, and the performance cannot be effectively used.

On the other hand, when the heat resistance of the heat sink is set so as to be used in a region where the wide band gap semiconductor can operate at a high temperature, the heat resistance can be increased, so that the heat sink can be reduced in size.
However, it is necessary to increase the distance between the silicon semiconductor and the wide band gap semiconductor so that thermal interference occurs between the semiconductor elements on the upstream side and the downstream side of the cooling air, and the usage temperature of the silicon semiconductor is not exceeded. The heat sink becomes larger.

In the power conversion device described in Patent Document 1, two heat sinks having different thermal resistances are used, and there is an unsolved problem that production costs increase due to an increase in the number of parts such as mounting structure parts due to differences in shape. Occurs.
In the semiconductor power conversion device described in Patent Document 2, when a groove is formed in the base plate of the heat sink, the heat sink is not divided at the lower part of the groove, so that the heat flow reduction effect by heat conduction is limited. There is an unresolved problem that it must be.

  Therefore, the present invention has been made paying attention to the unsolved problems of the invention described in Patent Documents 1 and 2, and is small in size while suppressing thermal interference between semiconductor modules arranged on a heat sink. An object of the present invention is to provide a semiconductor point force conversion device that can be realized.

  According to an aspect of the present invention, the first semiconductor module that performs power conversion including the first semiconductor element, and the second semiconductor module that performs power conversion including the second semiconductor element having a higher operating temperature than the first semiconductor element. A semiconductor module, a first semiconductor module and a second semiconductor module are mounted on a mounting surface, and a heat sink having a cooling air passage is provided. The heat sink mounts the first semiconductor module formed on the upstream side of the cooling air passage. A semiconductor power conversion device having at least one mounting surface, a second mounting surface for mounting the second semiconductor module formed on the downstream side of the cooling air passage, and a slit formed between the first mounting surface and the second mounting surface I will provide a.

  According to one aspect of the present invention, when mounting the first semiconductor module and the second semiconductor module having a high operating temperature on the first semiconductor module on the same heat sink, between the first semiconductor module and the second semiconductor module. By forming a slit in the power converter, it is possible to reduce the thermal interference between the semiconductor modules and reduce the size of the power converter.

1 is a plan view showing a semiconductor power conversion device according to a first embodiment of the present invention. It is a front view of FIG. It is a left view of FIG. It is sectional drawing which shows the modification of 1st Embodiment. It is a top view which shows the semiconductor power converter device according to the 2nd Embodiment of this invention. FIG. 6 is a front view of FIG. 5. It is a top view which shows the semiconductor power converter device according to the 3rd Embodiment of this invention. FIG. 8 is a front view of FIG. 7. It is a circuit diagram which shows an inverter apparatus. It is a top view which shows the conventional power converter device. It is a figure which shows the conventional semiconductor power converter device, (a) is a top view, (b) is a front view, (c) is a side view.

Hereinafter, a semiconductor power conversion device according to one embodiment of the present invention will be described with reference to the drawings.
The semiconductor power conversion device 10 according to one aspect of the present invention includes a plurality of, for example, three first semiconductor modules 20a, 20b, and 20c in which the maximum use temperature is set to about 125 ° C. to 150 ° C., and the maximum use temperature is the first. A plurality of, for example, three second semiconductor modules 30 </ b> A, 30 </ b> B, and 30 </ b> C set to about 200 ° C. or higher that are higher than the semiconductor modules 20 a to 20 c are provided.

  The first semiconductor elements constituting the first semiconductor modules 20A, 20B and 20C are constituted by silicon semiconductor elements, and connected in series, for example, constituting the diode arms 202A to 202C of the diode rectifier 200 in the inverter device of FIG. 9 described above. The first semiconductor element includes two diodes. The first semiconductor modules 20A, 20B, and 20C constitute a three-phase diode rectifier, and perform AC-DC power conversion for converting a commercial AC power source into a DC voltage.

  The second semiconductor element constituting the second semiconductor modules 30A, 30B and 30C is a wide band gap formed of a semiconductor whose main component is any one of silicon carbide (SiC), gallium nitride (GaN) -based material, diamond and the like. It is composed of semiconductor elements. Each of the second semiconductor modules 30A to 30C is, for example, a semiconductor switching element constituted by an IGBT, a power MOSFET, or the like as a second semiconductor element that constitutes the switching arms 404A to 404C of the inverter circuit 400 in the inverter device of FIG. It includes two parallel circuits of 401 and a diode 402 in series.

Further, the semiconductor power conversion device 10 includes a rectangular heat sink 40 as viewed from the plane on which the first semiconductor modules 20A to 20C and the second semiconductor modules 30A to 30C are mounted on the front surface, and a back surface side of the heat sink 40. And a suction-type cooling fan 50 provided at one end in the longitudinal direction.
The heat sink 40 is made of a metal material having high thermal conductivity such as copper, aluminum, or an alloy thereof. The heat sink 40 includes, for example, a mounting plate portion 42 whose front surface is a module mounting surface 41, and a plurality of. It is comprised with the radiation fin 43. FIG.

As shown in FIGS. 2 and 3, each of the heat dissipating fins 43 is formed in a flat plate shape extending in the longitudinal direction of the mounting plate portion 42, and a plurality of the fins 43 are arranged in parallel at predetermined intervals in the width direction of the mounting plate portion 42. Has been. And between the radiation fins 43, a cooling air passage 44 through which the cooling air from the cooling fan 50 passes from the other end in the longitudinal direction of the heat sink 40 toward the cooling fan 50 is formed.
A first mounting surface 45 in which the first semiconductor modules 20 </ b> A to 20 </ b> C are mounted is formed on the module mounting surface 41 of the mounting plate portion 42 at a position facing the upstream side of the cooling air passage 44. A second mounting surface 46 on which the second semiconductor modules 30A to 30C are mounted is formed at a position facing the side. Here, the first semiconductor modules 20 </ b> A to 20 </ b> C are mounted on the first mounting surface 45 so as to be aligned at a predetermined interval in the width direction intersecting the cooling air passage 44. Similarly, the second mounting surface 46 has a predetermined interval in the width direction intersecting the cooling air passage 44 so that the second semiconductor modules 30A to 30C face the first semiconductor modules 20A to 20C with a predetermined interval. Keeping them aligned and implemented.

  The mounting plate portion 42 is formed with a slit 47 extending between the first mounting surface 45 and the second mounting surface 46 in the width direction intersecting with the cooling air passage 44. The slit 47 penetrates in the thickness direction of the front and back of the mounting plate portion 42, and the first semiconductor modules 20 </ b> A to 20 </ b> C and the second mounting surface 46 mounted on the first mounting surface 45 facing each other by the slit 47. It is possible to divide between the mounted second semiconductor modules 30 </ b> A to 30 </ b> C and greatly reduce thermal interference between them.

Next, the operation of the above embodiment will be described.
The first semiconductor modules 20A to 20C constituted by silicon semiconductor elements including diode arms constituting the diode rectifier of the inverter device are attached to the first mounting surface 45 on the front surface of the mounting plate portion 42 of the heat sink 40 by die-bonding bonding or the like. It joins by the joining method of. Similarly, the second semiconductor modules 30A to 30C composed of wide band gap semiconductor elements including switching arms constituting the inverter circuit of the inverter device are die-bonded to the second mounting surface 46 on the front surface of the mounting plate portion 42. It joins by joining methods, such as joining.

In this state, the cooling fan 50 is rotationally driven to suck in the gas, whereby the cooling air flows from the opposite side of the cooling fan 50 toward the cooling fan 50 in the cooling air passage 44 formed between the adjacent radiating fins 43. .
At this time, when the inverter device is operated, the first semiconductor modules 20A to 20C including the diode arms constituting the diode rectifier and the second semiconductor modules 30A to 30C including the switching arms constituting the inverter circuit generate their own losses ( Temperature rise occurs due to steady loss and switching loss. At this time, the maximum use temperature of the first semiconductor modules 20A to 20C is about 125 ° C to 150 ° C, and the maximum use temperature of the second semiconductor modules 30A to 30C is 200 ° C or higher.

Heat generated by the first semiconductor modules 20A to 20C and the second semiconductor modules 30A to 30C is transmitted to the heat radiating fins 43 via the mounting plate portion 42 of the heat sink 40, and further transmitted to the heat radiating fins 43 to be the cooling air passage 44. Heat is exchanged with the cooling air passing through and the temperature rise is suppressed.
At this time, the first semiconductor modules 20A to 20C are mounted on the first mounting surface 45 facing the upstream side of the cooling air passage 44, and the second semiconductor modules 30A to 30C are facing the downstream side of the cooling air passage 44. It is mounted on the second mounting surface. For this reason, by setting the thermal resistance of the heat sink 40 in accordance with the first semiconductor modules 20A to 20C having the lowest maximum operating temperature, the cooling air flows upstream of the cooling air passage 44 from the first semiconductor modules 20A to 20C. After heat exchange, the heat generated by the first semiconductor modules 20A to 20C can be radiated through the radiation fins 43 and controlled to be within a maximum operating temperature of about 125 ° C to 150 ° C.

  Then, since the cooling air heated by heat exchange with the first semiconductor modules 20A to 20C is supplied to the second semiconductor modules 30A to 30C on the downstream side, the heat generated by the second semiconductor modules 30A to 30C is transmitted. By exchanging heat with the radiating fins 43, the second semiconductor modules 30 </ b> A to 30 </ b> C can be maintained at a higher use temperature of 200 ° C. or higher than the first semiconductor modules 20 </ b> A to 20 </ b> C.

  Thus, the first semiconductor modules 20A to 20C and the second semiconductor modules 30A to 30C are operated at different use temperatures. In this case, a slit 47 extending in the width direction is formed between the first mounting surface 45 on which the first semiconductor modules 20A to 20C are mounted and the second mounting surface 46 on which the second semiconductor modules 30A to 30C are mounted. Therefore, the slit 47 divides the first mounting surface 45 and the second mounting surface 46. Therefore, the heat through the mounting plate portion 42 between the first semiconductor modules 20A to 20C mounted on the first mounting surface 45 and the second semiconductor modules 30A to 30C mounted on the second mounting surface 46 by the slit 47. It is possible to greatly suppress general interference. For this reason, it becomes possible to shorten the distance between the 1st mounting surface 45 and the 2nd mounting surface 46, the longitudinal direction length of the heat sink 40 can be shortened, and the semiconductor power converter device 10 can be reduced in size.

In this case, as shown in FIG. 4, thermal interference between the first mounting surface 45 and the second mounting surface 46 is formed by forming the groove 48 facing the slit 47 also on the heat radiating fin 43 facing the slit 47. Can be further reduced.
Although not shown, the semiconductor power conversion device 10 can be arranged in a casing and can be cooled by forced convection in the casing by the cooling fan 50. Further, the cooling fan 50 is exposed to the cooling air discharge port formed in the housing, and the heat radiation fin 43 on the opposite side of the cooling fan 50 of the heat sink 40 is allowed to face the cooling air supply port, thereby cooling by the outside air. You can also Further, a heat exchanger having a gas passage may be arranged on the opposite side of the heat sink 40 from the cooling fan 50 to exchange heat with the refrigerant to obtain cooling air.

Next, a second embodiment showing one aspect of the present invention will be described with reference to FIGS.
In the second embodiment, the slit shape formed in the mounting plate portion 42 of the heat sink 40 is changed.
That is, in the second embodiment, the slit 47 in the first embodiment described above is divided into three so as to be formed only on the facing surfaces of the first semiconductor modules 20A to 20C and the second semiconductor modules 30A to 30C. The slits 47a to 47c are configured.

The other configurations have the same configurations as those of the first embodiment, and the same reference numerals are given to corresponding portions with the first embodiment, and the detailed description thereof will be omitted.
According to the second embodiment, the slit 47 formed in the mounting plate portion 42 is divided into three slits 47a to 47c, and each of the slits 47a to 47c is the first semiconductor module 20A to 20C and the second semiconductor module 30A to 30C. Are formed at positions facing each other. For this reason, while being able to acquire the same effect as 1st Embodiment mentioned above, except between the opposing slits, ie, the opposing part of 1st semiconductor module 20A-20C and 2nd semiconductor module 30A-30C. Since the slit is not formed and the mounting plate part 42 is continuous without being divided, it is possible to suppress the decrease in the mechanical strength of the mounting plate part 42 due to the formation of the slit and improve the durability. .

Next, a third embodiment of the semiconductor power conversion device according to one aspect of the present invention will be described with reference to FIGS.
In the third embodiment, the slit formed in the mounting plate portion of the heat sink is formed more finely.
That is, in the third embodiment, a plurality of narrow slits 47d are arranged in a staggered manner so that a part thereof overlaps in the longitudinal direction of the mounting plate portion.

About another structure, it has the structure similar to 1st and 2nd embodiment, the same code | symbol is attached | subjected to the corresponding part with 1st and 2nd embodiment, and the detailed description is abbreviate | omitted.
According to the third embodiment, since the narrow slits 47d are arranged in a staggered manner so as to partially overlap in the longitudinal direction of the mounting plate portion 42, the first semiconductor modules 20A to 20C and the second semiconductor module While being able to lengthen the heat conduction distance between 30A-30C, it is possible to reduce the cross-sectional area of the heat conduction path between the slits 47d. Therefore, the thermal conductivity between the first semiconductor modules 20A to 20C and the second semiconductor modules 30A to 30C at the slit forming position can be reduced, and the effect of reducing the thermal interference is the first. This can be further enhanced as compared with the embodiment and the second embodiment.

  In each of the above embodiments, the case where three first semiconductor modules and three second semiconductor modules are aligned in parallel has been described. However, the present invention is not limited to this, and the amount of current flowing through the semiconductor power conversion device 10 is not limited thereto. When increasing, 3n (n is an integer greater than or equal to 2) 1st semiconductor modules and 2nd semiconductor modules may be arranged in parallel. Further, only one set of the first semiconductor module and the second semiconductor module may be arranged to face the mounting plate portion 42. Further, the diodes 201 of the diode rectifier 200 are modularized one by one to form a first semiconductor module. Similarly, the parallel circuit of the semiconductor switching element and the diode of the inverter circuit 400 is also modularized one by one to form the second semiconductor module. can do.

In each of the above embodiments, the case where the radiation fins 43 of the heat sink 40 are formed in a flat plate shape has been described. However, the present invention is not limited to this, and the heat sink 40 is formed in a pin shape such as a cylinder or a prism. Also good.
Further, in each of the above embodiments, the case where the cooling fan 50 is arranged to be a suction type has been described. However, the present invention is not limited to this, and the cooling fan 50 is arranged to be a discharge type on the other end side of the heat sink 40. Then, the cooling air may be supplied to the cooling air passage.

DESCRIPTION OF SYMBOLS 10 ... Semiconductor power converter 20A-20C ... 1st semiconductor module 30A-30C ... 2nd semiconductor module 40 ... Heat sink 41 ... Module mounting surface 42 ... Mounting board part 43 ... Radiation fin 44 ... Cooling air path 45 ... 1st mounting surface 46 ... 2nd mounting surface 47, 47a-47d ... Slit 50 ... Cooling fan

Claims (9)

A first semiconductor module including the first semiconductor element for performing power conversion;
A second semiconductor module that performs power conversion including a second semiconductor element having a high operating temperature relative to the first semiconductor element;
Mounting the first semiconductor module and the second semiconductor module on a mounting surface, and a heat sink having a cooling air passage;
The heat sink has a first mounting surface for mounting the first semiconductor module formed on the upstream side of the cooling air passage, and a second mounting surface for mounting the second semiconductor module formed on the downstream side of the cooling air passage. And a slit formed between the first mounting surface and the second mounting surface. A semiconductor power conversion device comprising:   The heat sink is provided on the side opposite to the first mounting surface and the second mounting surface of the mounting plate portion formed with the first mounting surface, the second mounting surface and the slit. The semiconductor power conversion device according to claim 1, comprising a plurality of radiating fins forming the cooling air passage.   The semiconductor power conversion device according to claim 2, wherein the slit extends in a direction intersecting with the cooling air passage and is formed to penetrate the mounting plate portion.   4. The semiconductor power conversion device according to claim 1, wherein a cooling fan is provided on at least one end side of the cooling air passage of the heat sink. 5.   5. The semiconductor power conversion according to claim 1, wherein the first semiconductor element is formed of a silicon semiconductor element, and the second semiconductor element is formed of a wide band gap semiconductor element. 6. apparatus.   The heat sink has a plurality of the first semiconductor modules arranged on the first mounting surface in a direction intersecting the cooling air passage, and the plurality of second semiconductor modules are arranged on the second mounting surface with the cooling air. 6. The semiconductor power conversion device according to claim 1, wherein the semiconductor power conversion device is aligned in a direction intersecting with the passage.   7. The slit according to claim 1, wherein the slit is formed to extend in a direction crossing the cooling air passage so as to divide the first semiconductor module and the second semiconductor module. 2. The semiconductor power conversion device according to item 1.   The semiconductor power conversion device according to claim 6, wherein the slit is formed to extend in a direction intersecting the cooling air passage between the first semiconductor module and the second semiconductor module facing each other.   The slit is extended in a direction intersecting the cooling air passage between at least a first semiconductor module and a second semiconductor module facing each other, and a plurality of the slits are formed in parallel. Semiconductor power conversion device.

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