JP2018046191A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for making effective use of a heat reservoir, in a power converter including a lamination unit laminating a semiconductor module and a cooler, and the heat reservoir for temporarily reserving the heat which cannot be absorbed by the cooler.SOLUTION: A power converter 2 includes a lamination unit 20 and a heat reservoir 37. The lamination unit 20 is a lamination laminating a semiconductor module 3 housing a transistor for power conversion, and a cooler 22. Each of multiple semiconductor modules 3 and the heat reservoir 37 are connected by a heat transmission member (a middle point terminal 25c and a heat slinger 41). One heat reservoir 37, which is thermally connected with the multiple semiconductor modules 3, absorbs local or temporal heat quantity produced in the lamination unit 20, and disperses it spatially or temporarily.SELECTED DRAWING: Figure 4

Description

  The present specification relates to a power conversion system including a plurality of semiconductor modules containing semiconductor elements for power conversion, and a plurality of coolers in which refrigerant flow paths are formed and stacked alternately with the semiconductor modules. An apparatus is disclosed.

  For example, Patent Literatures 1-3 disclose a power conversion device including the semiconductor module and the cooler described above. Any of the power conversion devices of any document converts the electric power of the battery into the driving electric power of the traveling motor in the electric vehicle. Since the power conversion device of an electric vehicle handles a large amount of power, the semiconductor module generates a large amount of heat, and the above power conversion device capable of cooling each semiconductor module from both sides has excellent cooling capacity.

  The power conversion device of Patent Document 2 is a part of a stack of a plurality of semiconductor modules and a plurality of coolers in order to cope with a temporary increase in heat generation amount of a specific semiconductor module, such as during sudden acceleration or sudden start. In addition, a heat storage body (heat mass) is sandwiched. In the power conversion device of Patent Document 3, a heat storage body is sandwiched between a stack of a plurality of semiconductor modules and a plurality of coolers, and another heat generator is brought into contact with the heat storage body. Can also be cooled. Hereinafter, a stacked body of a plurality of semiconductor modules and a plurality of coolers may be referred to as a stacked unit.

JP 2012-238881 A JP 2011-1000079 A JP 2009-261125 A

  In the power conversion device of Patent Document 2, the semiconductor module located in the vicinity of the heat storage body can cause the heat storage body to absorb the amount of heat temporarily increased, but the semiconductor module far from the heat storage body cannot use the heat storage body. If semiconductor modules that may temporarily increase the amount of heat are scattered in the stacked units, it is necessary to arrange heat storage bodies for each semiconductor module, increasing the length of the stacked units. End up. There is room for improvement in the structure incorporating a heat storage element.

  A power conversion device disclosed in the present specification includes a plurality of semiconductor modules that house semiconductor elements for power conversion, and a plurality of coolers in which coolant flow paths are formed and are stacked alternately with the semiconductor modules. And it has a heat storage. Each of the plurality of semiconductor modules and the heat storage body are connected by a heat transfer member. In other words, the power conversion device disclosed in this specification connects a plurality of semiconductor modules to one heat storage body by a heat transfer member. By doing so, a plurality of semiconductor modules can use one heat storage body in common. There is no need to sandwich a number of heat storage elements of the laminated unit, and an increase in the length of the laminated unit can be suppressed. Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is a block diagram of the electric power system of the electric vehicle containing the power converter device of an Example. It is a top view which shows the component layout inside the housing | casing of a power converter device. It is a front view which shows the component layout inside the housing | casing of a power converter device. It is sectional drawing of a lamination | stacking unit. It is a front view which shows the component layout inside the housing | casing of the power converter device which mounts the lamination | stacking unit of a modification. It is a side view of the lamination | stacking unit of a modification.

  A power converter 2 according to an embodiment will be described with reference to the drawings. The power conversion device 2 according to the embodiment is a device that is mounted on an electric vehicle and converts battery power into driving power for a travel motor. First, the electric system of the electric vehicle 100 including the power conversion device 2 will be described. FIG. 1 is a block diagram of a power system of an electric vehicle 100 including a power conversion device 2. The power conversion device 2 boosts the DC power of the battery 13, converts it to AC, and supplies it to the traveling motors 15 a and 15 b. The DC terminal of the power conversion device 2 is connected to the battery 13 via the system main relay 14, and the AC terminal is connected to the two motors 15a and 15b.

  The electric vehicle 100 combines the outputs of the two motors 15 a and 15 b with the gear box 16 and transmits power to the axle 17 to travel. The electric vehicle 100 can also generate electric power by reversely driving the motors 15a and 15b from the axle side using the kinetic energy of the vehicle. The battery 13 is charged with the power obtained by the power generation. The electric power obtained by using the kinetic energy of the vehicle is sometimes called regenerative electric power.

  The power converter 2 includes a voltage converter 12 that boosts the voltage of the battery 13 and two inverters 10a and 10b that convert DC power into AC power. The voltage converter 12 includes a filter capacitor 4, a reactor 5, two transistors 9a and 9b, and two diodes. The two transistors 9a and 9b are connected in series, and a diode is connected in antiparallel to each of the transistors 9a and 9b. Transistors 9a and 9b and diodes, that is, a range surrounded by a broken line 3a in FIG. 1, corresponds to a semiconductor module 3a described later. The voltage converter 12 has a function of stepping up the voltage of the battery 13 and also has a step-down function of stepping down the voltage of regenerative power sent from the inverters 10a and 10b and supplying it to the battery 13, so-called bidirectional. It is a DC-DC converter. Since the circuit configuration of the voltage converter 12 in FIG. 1 is well known, detailed description thereof is omitted.

  The inverter 10a includes six transistors 9c-9h and a diode connected in antiparallel to each transistor. Two of the six transistors 9c-9h are connected in series. Transistors 9c and 9d, 9e and 9f, and 9g and 9h are connected in series, respectively. The three sets of series connections are connected in parallel. AC is output from the midpoint of each series connection. Dashed lines 3b, 3c, and 3d correspond to semiconductor modules, respectively.

  The inverter 10b has the same configuration as the inverter 10a. That is, the inverter 10b also includes three semiconductor modules 3e, 3f, and 3g. Each semiconductor module 3e-3g includes two transistors and two diodes. A smoothing capacitor 6 is connected in parallel between the voltage converter 12 and the inverters 10a and 10b. The transistors 9a-9h and the transistors built in the inverter 10b correspond to power conversion switching elements.

  The transistors of the seven semiconductor modules 3a to 3g operate by receiving drive signals (PWM signals) from a controller (not shown). Hereinafter, when any one of the seven semiconductor modules 3a to 3g is shown without distinction, it is referred to as a semiconductor module 3.

  A hardware configuration of the power conversion device 2 will be described. In FIG. 2, the top view of the power converter device 2 is shown. FIG. 2 is a plan view showing a component layout inside the housing 30 with the cover removed. The front view of the power converter device 2 is shown in FIG. FIG. 3 is a front view showing a component layout inside the housing 30 by cutting the right housing wall in FIG. 2.

  The semiconductor module 3 is a package in which two transistors and two diodes are sealed in a main body 21. The main body 21 is made by resin injection molding. The seven semiconductor modules 3 together with the eight coolers 22 constitute a stacked unit 20. In FIG. 2, reference numeral 22 is given only to the coolers at both ends of the laminated unit 20, and reference numerals are omitted for the other coolers. The stacked unit 20 is a stacked body in which seven semiconductor modules 3 (3a-3g) and eight coolers 22 are alternately stacked one by one. The cooler 22 is provided with a flow path through which the liquid refrigerant passes. A pair of coolers 22 adjacent to each other with one semiconductor module 3 interposed therebetween are connected by two connecting pipes 23. In FIG. 2, reference numeral 23 is attached to only one connecting pipe, and reference numerals are omitted for the other connecting pipes. All the coolers 22 communicate with each other through the connecting pipe 23.

  In FIG. 2, a refrigerant introduction pipe 34 and a refrigerant discharge pipe 35 are connected to the rightmost cooler 22. One of the two connecting pipes 23 that connect the pair of adjacent coolers 22 is positioned so as to overlap the refrigerant introduction pipe 34 when viewed from the stacking direction (X direction in the figure), and the other connecting pipe 23 is The refrigerant discharge pipe 35 is positioned so as to overlap. The refrigerant introduction pipe 34 and the refrigerant discharge pipe 35 pass through a through hole 30 a provided in the casing 30, and one end protrudes to the outside of the casing 30. A refrigerant circulation device (not shown) is connected to the refrigerant introduction pipe 34 and the refrigerant discharge pipe 35. The liquid refrigerant supplied through the refrigerant introduction pipe 34 is distributed to all the coolers 22 through one connection pipe 23 that connects a pair of adjacent coolers 22. The liquid refrigerant absorbs heat from the adjacent semiconductor module 3 while passing through each cooler 22 and is discharged out of the power converter 2 through the other connecting pipe 23 and the refrigerant discharge pipe 35 (to the refrigerant circulation apparatus). Is returned). The liquid refrigerant is, for example, LLC (Long Life Coolant).

  Three power terminals 25 (a positive terminal 25a, a negative terminal 25b, and a midpoint terminal 25c) extend from the upper surface of each semiconductor module 3. A plurality of control terminals 27 extend from the lower surface of each semiconductor module 3 (see FIG. 3). Each semiconductor module 3 accommodates a series connection of two transistors, and the positive electrode terminal 25 a is connected to the high potential side of the series connection inside the main body 21 of the semiconductor module 3. The negative electrode terminal 25b is connected to the low potential side in series connection inside the main body 21, and the midpoint terminal 25c is connected to the midpoint of series connection. The positive terminal 25a and the negative terminal 25b of each semiconductor module 3 are connected to the smoothing capacitor 6 via the positive bus bar 31 and the negative bus bar 32, respectively. In FIG. 2, the connection destination of the midpoint terminal 25c of each semiconductor module 3 is not shown. In FIG. 3, only a part of the output bus bar 39 connected to the midpoint terminal 25c is shown. Midpoint terminals 25 c of the plurality of semiconductor modules 3 a to 3 g pass through the heat storage body 37. The heat storage body 37 will be described later.

  The control terminal 27 is connected to a gate terminal connected to the gate of each transistor inside the semiconductor module 3, a sense emitter terminal connected to the sense emitter of each transistor, and a temperature sensor built in the semiconductor module 3. Sensor terminals. The control terminal is connected to a control board 29 arranged below the stacked unit 20. The control board 29 receives a command from an upper controller (not shown) and supplies a drive signal to each transistor housed in each semiconductor module 3.

  One end of the stacking unit 20 of the plurality of semiconductor modules 3 and the plurality of coolers 22 in the stacking direction is in contact with the support wall 36 provided in the housing 30, and the other end is in contact with the support pillar 38 via the leaf spring 33. It is supported. The laminated unit 20 receives a load in the laminating direction by the leaf spring 33. Due to the load in the stacking direction, the cooler 22 and the semiconductor module 3 are in close contact with each other, and the efficiency of heat transfer from the semiconductor module 3 to the cooler 22 is increased. A filter capacitor 4, a reactor 5, and a smoothing capacitor 6 are disposed around the multilayer unit 20. The connection between them and the laminated unit 20 is omitted except for the bus bars 31 and 32.

  The heat storage body 37 will be described. FIG. 4 is a cross-sectional view of the laminated unit 20 cut along an XZ plane that crosses the midpoint terminal 25c. In FIG. 4, illustration of some coolers 22 and the semiconductor modules 3 c-3 e in the middle of the stacked unit 20 is omitted. First, the internal structure of the semiconductor module 3a will be described. Inside the semiconductor module 3 a, the transistor chip 42 and the spacer 43 are sandwiched between the two heat radiation plates 41 and 44. The two heat sinks 41 and 44 and the spacer 43 are made of copper that well transmits electricity and heat. A fin 45 is provided inside the cooler 22. The fins 45 are in contact with the inner sides of both side plates (side plates in contact with the semiconductor module) of the cooler 22.

  The two heat sinks 41 and 44, the transistor chip 42, and the spacer 43 are embedded in the resin main body 21, and one wide surface of each of the heat sinks 41 and 44 is exposed from the main body 21. Although not visible in FIG. 4, another transistor chip is embedded on the back side of the main body 21 in the drawing. Transistors different from the transistor chip 42 correspond to the transistors 9a and 9b in FIG. The transistor chip 42 has a flat plate shape, and an emitter electrode and a collector electrode are exposed on each wide surface. The collector electrode is joined to one heat sink 41 and the emitter electrode is joined to the other heat sink 44 via a spacer 43. A midpoint terminal 25 c is connected to one end of the heat sink 41. That is, the heat sink 41 not only transfers the heat of the transistor chip 42 to the surface of the main body, but also forms a part of a conductive path for conducting the collector electrode of the transistor chip 42 to the outside of the main body 21. The heat radiating plate 44 is connected to the negative electrode terminal 25b on the back side of the drawing.

  The radiator plate 41 is also connected to an emitter electrode of another transistor chip located on the back side of the sheet of FIG. Therefore, the heat radiating plate 41 also plays a role of connecting two transistor chips in series. The radiator plates 41 and 44 exposed on the surface of the main body 21 of the semiconductor module 3 are in contact with the cooler 22. The heat of the transistor chip 42 and another transistor chip sealed in the main body 21 is absorbed by the cooler 22 through the radiator plates 41 and 44. When the cooler 22 is made of a conductive material, an insulating plate is sandwiched between the heat sinks 41 and 44 and the cooler 22. Other semiconductor modules 3b-3g also have the same internal structure as the semiconductor module 3a.

  The heat accumulator 37 is connected to a midpoint terminal 25c connected to the transistor chip 42 and another transistor chip via the heat radiating plate 41. The midpoint terminals 25 c of all the semiconductor modules 3 a to 3 g are connected to the heat storage body 37. Similarly to the heat radiating plate 41, the midpoint terminal 25 c is made of copper that conducts heat well and may be expressed as a heat transfer member. Therefore, in other words, each of the plurality of semiconductor modules 3a to 3g and the heat storage body 37 are connected by the heat transfer member (the midpoint terminal 25c and the heat radiating plate 41). Of the amount of heat generated by the transistor chip 42 and another transistor chip, the amount that cannot be absorbed by the cooler 22 adjacent to the semiconductor module 3 is stored through the heat transfer member (the middle point terminal 25c and the heat radiating plate 41). 37 absorbs.

  The heat storage body 37 is made of, for example, a substance such as zeolite or silica (silicon oxide), or a metal such as copper. When a conductive metal such as copper is used, an insulator is sandwiched between the midpoint terminal 25 c and the heat storage body 37.

  The advantage of the heat storage body 37 will be described. One heat storage body 37 is thermally connected to the plurality of semiconductor modules 3a to 3g via heat transfer members (the middle point terminal 25c and the heat radiating plate 41). The heat storage body 37 temporarily receives the amount of heat that cannot be absorbed by the adjacent cooler 22 when any of the heat generation amounts of the semiconductor modules 3a to 3g temporarily increases. The amount of heat received by the heat accumulator 37 is absorbed by the cooler 22 when the heat generation amount of the semiconductor modules 3a to 3g decreases and a heat absorption margin occurs in the cooler 22.

  As shown in FIG. 1, the plurality of semiconductor modules 3a-3g are used for the voltage converter 12 (semiconductor module 3a), used for the inverter 10a for the motor 15a (semiconductor module 3b-3d), and the motor. There is one (semiconductor module 3e-3g) used for the inverter 10b for 15b. The semiconductor modules 3a to 3g are a set of semiconductor modules used in different circuits, and semiconductor modules that generate large amounts of heat differ depending on the situation. The amount of heat generated by the semiconductor module having a large amount of heat generated is not limited to the adjacent coolers 22, but is provided by another cooler 22 having a heat absorption margin via the heat transfer member (the middle point terminal 25 c and the heat sink 41) and the heat storage body 37. Can be absorbed. In other words, the heat storage body 37 connected to the plurality of semiconductor modules 3a to 3g and the heat transfer member (the middle point terminal 25c and the heat radiating plate 41) disperses the heat generated locally in the stacked unit 20 in a uniform direction. There is an effect to make.

  As described above, the heat storage body 37 receives a temporarily increasing amount of heat generated in the laminated unit 20 or a locally increasing amount of heat. Then, the received heat quantity is transferred to the cooler 22 in a temporally or spatially dispersed manner. Therefore, the plurality of coolers 22 need only have a capacity capable of absorbing the average heat generation of the stacked unit 20 in terms of time / space. The cooler 22 does not need the ability of absorbing the local or temporary high calorific value of the laminated unit 20, and the size can be reduced.

  Further, the heat storage body 37 is not sandwiched between the cooler 22 or the semiconductor module 3 in the laminated unit 20 but is disposed adjacent to the laminated unit 20. Therefore, the heat storage body 37 has an advantage that the length of the laminated unit 20 in the longitudinal direction is not increased.

  With reference to FIG. 5 and FIG. 6, the laminated unit 120 of a modification is demonstrated. FIG. 5 is a front view (a front view in which a part of the wall of the housing 30 is cut) of the power conversion device 102 including the laminated unit 120 of the modification. FIG. 6 is a side view of the laminated unit 120. The stacked unit 120 is accompanied by a heat storage body 137. In the previous laminated unit 20, the heat storage body 37 is connected to the semiconductor module 3 (inside the internal module 21 via the heat transfer member (the middle terminal 25 c and the heat radiation plate 41) in contact with the transistor chip 42 inside the main body 21 of the semiconductor module 3. Transistor). In the laminated unit 120 of the modified example, the heat transfer plate 136 is sandwiched between the adjacent semiconductor module 3 and the cooler 22, the branch portion 136 a is extended from the heat transfer plate 136, and the branch portion 136 a is connected to the heat storage body 137. ing. In other words, in the laminated unit 120 of the modified example, the heat transfer plate 136 is in contact with each of the plurality of semiconductor modules 3, and the plurality of semiconductor modules 3 are connected to one heat storage body 137 via the heat transfer plate 136. Thermally connected. In this modification, by changing the position and shape of the branch portion 136a of the heat transfer plate 136, it is possible to give a degree of freedom to the arrangement of the heat storage body 137.

  Points to be noted regarding the technology described in the embodiments will be described. The midpoint terminal 25c and the heat sink 41 of the embodiment correspond to an example of “heat transfer member” in the claims. The heat transfer plate 136 in the laminated unit 120 of the modification corresponds to another example of “heat transfer member” in the claims.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Power converter 3, 3a-3g: Semiconductor module 4: Filter capacitor 5: Reactor 6: Smoothing capacitor 9a-9h: Transistors 10a, 10b: Inverter 12: Voltage converter 13: Battery 14: System main relays 15a, 15b : Traveling motor 16: Gear box 17: Axle 20, 120: Laminating unit 21: Main body 22: Cooler 23: Connecting pipe 25 a: Positive terminal 25 b: Negative terminal 25 c: Midpoint terminal 27: Control terminal 29: Control board 30 : Housing 31: Positive electrode bus bar 32: Negative electrode bus bar 33: Leaf spring 34: Refrigerant introduction pipe 35: Refrigerant discharge pipe 36: Support wall 37, 137: Heat storage body 39: Output bus bar 41, 44: Heat sink 42: Transistor chip 43 : Spacer 45: Fin 100: Electric vehicle 136: Heat transfer plate 136 a: Branch

Claims (1)

A plurality of semiconductor modules containing semiconductor elements for power conversion;
A plurality of coolers in which a flow path of a refrigerant is formed and stacked alternately with the semiconductor module;
Thermal storage,
With
A power converter, wherein each of the plurality of semiconductor modules and the heat storage body are connected by a heat transfer member.

Images