JP7234783B2 - power converter - Google Patents

Description

The technology disclosed in this specification relates to a power converter.

A power conversion device is known in which a plurality of semiconductor modules and a plurality of coolers are alternately stacked. In such a power conversion device, pressure is applied in the stacking direction in order to ensure the adhesion between adjacent coolers and semiconductor modules and improve the cooling performance. For example, Patent Literature 1 discloses such a power converter. In Patent Document 1, the cooler is formed by combining a pair of metal plates (referred to as "outer shell plates" in Patent Document 1), and a flow path is formed inside for the coolant to flow. there is In order to suppress deformation of the metal plates due to pressure in the stacking direction, a portion of at least one of the pair of metal plates protrudes toward the other metal plate. The protruding portion constitutes a rib and is in contact with the other metal plate. With such a configuration, a power conversion device having high strength against pressure in the stacking direction is realized.

JP 2014-086505 A

In the technique disclosed in Patent Document 1, the strength against pressure in the lamination direction is improved by partially deforming the metal plate forming the cooler. In addition, inside the semiconductor module, a plurality of semiconductor elements are arranged in a direction crossing the flow path when viewed from the stacking direction, and ribs formed by deforming a part of the metal plate are provided between the adjacent semiconductor elements. is provided. This specification provides a technique for increasing the strength of the cooler as compared with the power converter of Patent Document 1.

In the power conversion device disclosed in this specification, a plurality of coolers are arranged in a line, semiconductor modules are sandwiched between adjacent coolers, and the coolers and semiconductor modules are stacked in the stacking direction. It is a power converter that is under pressure. A semiconductor module accommodates a plurality of semiconductor elements. Inside the cooler, a flow path is formed through which a coolant flows in a direction intersecting the stacking direction. Inside the cooler, a plurality of reinforcing members extending along the direction of the flow path and in contact with both one side of the cooler intersecting the stacking direction and the opposite side are arranged. Inside the semiconductor module, when viewed from the stacking direction, at least two semiconductor elements are arranged in a flow channel width direction that intersects with the flow channel direction. The plurality of reinforcing members are arranged so as not to overlap the semiconductor element when viewed from the stacking direction, and two reinforcing members are arranged on each side of the arrangement of the semiconductor elements in the flow channel width direction. is arranged between two semiconductor elements.

According to the above configuration, the strength of the cooler is improved by providing the reinforcing member inside the cooler. That is, there is no need to deform the metal plate that constitutes the cooler, and the strength of the cooler is improved. Further, by providing reinforcing members on both sides and in the middle in the direction in which the semiconductor elements are arranged, the strength is further improved. Details and further improvements of the technique disclosed in this specification are described in the following "Mode for Carrying Out the Invention".

1 is a perspective view of a power conversion device of an embodiment; FIG. It is a cross-sectional view of the power conversion device of the embodiment cut along the XZ plane. It is the top view which looked at the power converter device of an Example from the lamination direction.

A power conversion device 2 of an embodiment will be described with reference to the drawings. FIG. 1 is a perspective view of a power conversion device 2 of an embodiment. The power conversion device 2 of the embodiment is mounted on, for example, an electric vehicle, and performs power conversion between a battery and a motor. However, the power conversion device 2 of the embodiment is not limited to being mounted on an electric vehicle, and can be used as a power conversion device for various purposes.

The power conversion device 2 includes multiple coolers 10 and multiple semiconductor modules 20 . The power converter 2 is a device in which a plurality of coolers 10 and a plurality of semiconductor modules 20 are alternately stacked. In FIG. 1, only one cooler is denoted by 10, and the other coolers are omitted. Further, reference numeral 20 is attached to only one semiconductor module, and reference numerals are omitted for other semiconductor modules.

One semiconductor module 20 is sandwiched between two coolers 10 . An insulating plate 5 is sandwiched between the semiconductor module 20 and one cooler 10 and between the semiconductor module 20 and the other cooler 10, respectively. Also, in FIG. 1, one semiconductor module 20 and the insulating plates 5 on both sides thereof are extracted from the laminate for easy understanding.

Although details will be described later, the semiconductor module 20 includes semiconductor elements 21a, 21b, 22a, and 22b for power conversion. A semiconductor device used for power conversion is also called a power semiconductor device. A large amount of heat is generated when a large current flows through the power semiconductor element. Therefore, the power conversion device 2 is provided with a cooler 10 to cool these power semiconductor elements. By sandwiching one semiconductor module 20 between two coolers 10 from both sides, a power converter 2 with high cooling performance is realized.

The semiconductor module 20 and the cooler 10 are both of a flat plate type, and are stacked such that the flat surface (wide surface) having the largest area among the plurality of side surfaces faces each other. The semiconductor modules 20 and the coolers 10 are alternately stacked, and the coolers 10 are positioned at both ends of the power conversion device 2 in the stacking direction (the X direction in FIG. 1). Inside the cooler 10, a flow path is formed through which a coolant passes. The flow path direction in which the coolant flows is a direction orthogonal to the stacking direction (the Y direction in FIG. 1). A plurality of coolers 10 are communicated by communication pipes 4a and 4b. A coolant supply pipe 3a and a coolant discharge pipe 3b are connected to a cooler 10 positioned at one end in the stacking direction of the power conversion device 2 . A refrigerant supplied through the refrigerant supply pipe 3a is distributed to all the coolers 10 through the communicating pipe 4a. The coolant absorbs heat from adjacent semiconductor modules 20 while passing through each cooler 10 . The refrigerant that has passed through each cooler 10 passes through the communication pipe 4b and is discharged from the refrigerant discharge pipe 3b. The arrows in FIG. 1 indicate the direction in which the coolant flows. The coolant flowing through the cooler 10 is a liquid, such as water or LLC (Long Life Coolant).

A plate spring 6 is in contact with the cooler 10 positioned at the other end in the stacking direction of the power conversion device 2 . The leaf spring 6 is in contact with the surface of the cooler 10 opposite to the surface in contact with the semiconductor module 20 . The power conversion device 2 in which the semiconductor module 20, the insulating plate 5, and the cooler 10 are stacked is housed in a case (not shown) and is pressed by the plate spring 6 in the stacking direction. By applying pressure in the stacking direction, the adhesion between the cooler 10, the insulating plate 5, and the semiconductor module 20 is improved. Thereby, the cooling performance of the power converter 2 is improved. Further, grease is applied between the cooler 10 and the insulating plate 5 and between the insulating plate 5 and the semiconductor module 20 . Grease is applied to improve heat transfer efficiency.

Next, the semiconductor module 20 will be explained. The semiconductor module 20 is a device in which four semiconductor elements 21a, 21b, 22a, and 22b are sealed in a resin package. The semiconductor elements 21a and 21b are switching elements for power conversion, and are IGBTs (Insulated Gate Bipolar Transistors) in this embodiment. The power converter 2 converts power by selectively using two switching elements (semiconductor elements 21a and 21b). The semiconductor element 22a is a free wheel diode connected in anti-parallel with the semiconductor element 21a. The semiconductor element 22b is a free wheel diode connected in anti-parallel with the semiconductor element 21b. The semiconductor element 21a and the semiconductor element 21b are arranged in the flow direction (the Y direction in FIG. 1). Moreover, the semiconductor element 22a and the semiconductor element 22b are arranged in the direction of the flow path. Furthermore, the semiconductor element 21a and the semiconductor element 22a are arranged in the channel width direction (the Z direction in FIG. 1) intersecting the channel direction. The channel width direction is a direction orthogonal to the channel direction. The semiconductor element 21b and the semiconductor element 22b are arranged in the width direction of the flow path.

Electrodes are provided on the surfaces of the semiconductor elements 21a, 21b, 22a, and 22b, respectively. Four heat sinks 27a, 27b, 28a, and 28b are exposed on the wide surface of the package facing the insulating plate 5. As shown in FIG. Although not visible in FIG. 1, four radiator plates 27a, 27b, 28a, and 28b are also exposed on the wide surface on the opposite side. The semiconductor element 21a is sandwiched between heat sinks 27a provided on each of the two wide surfaces. Similarly, the semiconductor element 21b is sandwiched between heat sinks 27b provided on each of the two wide surfaces. The semiconductor element 22a is sandwiched between heat sinks 28a provided on each of the two wide surfaces. The semiconductor element 22b is sandwiched between heat sinks 28b provided on each of the two wide surfaces. The radiator plates 27a, 27b, 28a, and 28b are made of a material with excellent thermal conductivity, such as copper or aluminum. The heat sink 27a (27b, 28a, 28b) is electrically connected to the electrodes of the semiconductor element 21a (21b, 22a, 22b).

The semiconductor module 20 further includes a positive terminal 24 , a negative terminal 25 and a midpoint terminal 26 . A positive terminal 24, a negative terminal 25, and a midpoint terminal 26 extend from a narrow surface that intersects the flat surface (wide surface) of the package. The semiconductor elements 21a and 21b are connected in series inside the package, and the positive and negative sides of the series connection are electrically connected to the positive terminal 24 and the negative terminal 25, respectively. The midpoint of the serial connection of the two semiconductor elements 21a and 21b is electrically connected to the midpoint terminal 26. FIG.

The radiator plate 27a plays a role of transferring the heat of the semiconductor element 21a to the cooler 10 and also plays a role of a conductive path connecting the electrodes of the semiconductor element 21a and the terminals 24, 25 and 26. As shown in FIG. Similarly, the radiator plate 27b plays a role of transferring the heat of the semiconductor element 21b to the cooler 10 and also plays a role of a conductive path connecting the electrodes of the semiconductor element 21b and the terminals 24, 25 and 26. FIG. The radiator plate 28a plays a role of transferring the heat of the semiconductor element 22a to the cooler 10 and also plays a role of a conductive path connecting the electrodes of the semiconductor element 22a and the terminals 24, 25 and 26. As shown in FIG. The radiator plate 28b plays a role of transferring the heat of the semiconductor element 22b to the cooler 10 and also plays a role of a conductive path connecting the electrodes of the semiconductor element 22b and the terminals 24, 25, and 26. As shown in FIG. As described above, each heat sink is electrically connected to one of the semiconductor elements, so the insulating plate 5 is interposed between the semiconductor module 20 and the cooler 10 . Note that the cooler 10 is made of a material having excellent thermal conductivity, such as copper or aluminum.

The semiconductor module 20 further comprises two sets of control terminals 23a, 23b. Two sets of control terminals 23a, 23b extend from the narrow side opposite the narrow side from which the terminals 24, 25, 26 extend. The control terminal 23a is a group of terminals electrically connected to the gate of the semiconductor element 21a and the temperature sensor. The control terminal 23b is a group of terminals electrically connected to the gate of the semiconductor element 21b and the temperature sensor.

As described above, in the power conversion device 2 in which a plurality of semiconductor modules and a plurality of coolers are alternately stacked, in order to ensure the adhesion between adjacent coolers and semiconductor modules and improve the cooling performance, pressure is applied. As the pressure in the stacking direction increases, the adhesion between the cooler and the semiconductor module improves. However, if the pressure in the stacking direction is excessively increased, the cooler may become unable to withstand the pressure and may be deformed. If the cooler deforms, the adhesion between the cooler and the semiconductor module deteriorates. That is, the cooling performance of the power converter may deteriorate. The power conversion device 2 of the embodiment has a structure that improves the strength of the cooler.

The internal structure of the cooler 10 will be described with reference to FIGS. 2 and 3. FIG. FIG. 2 is a cross-sectional view of the power converter 2 cut along the XZ plane. FIG. 3 is a plan view of the power conversion device 2 viewed from the stacking direction.

Inside the cooler 10, reinforcing members 11, 12, 13 and fins 15 are provided. The reinforcing members 11, 12, and 13 are elongated members arranged to extend along the direction of the flow path. The reinforcing members 11, 12, 13 are in contact with both one surface of the cooler 10 intersecting the stacking direction and the opposite surface thereof. The reinforcing members 11, 12, 13 are fixed to the cooler 10 by brazing.

As described above, the semiconductor module 20 accommodates four semiconductor elements 21a, 21b, 22a, and 22b. The semiconductor elements 21a and 22a are arranged in the flow channel width direction (Z direction), and the semiconductor elements 21b and 22b are also arranged in the flow channel width direction. The reinforcing members 11 and 13 are arranged on both sides of the plurality of semiconductor elements 21a and 22a (21b and 22b) in the flow channel width direction. The reinforcing member 12 is arranged between the plurality of semiconductor elements 21a, 22a (21b, 22b) in the width direction of the flow path. Moreover, as described above, the reinforcing members 11, 12, and 13 have an elongated shape and are arranged so as to extend in the direction of the flow path (Y direction). Further, the reinforcing members 11, 12 and 13 are arranged so as not to overlap the semiconductor elements 21a, 21b, 22a and 22b when viewed from the stacking direction. The reinforcing members 11, 12, 13 are rectangular in cross section.

The following effects are expected from the plurality of reinforcing members 11 , 12 , 13 . The plurality of reinforcing members 11, 12, 13 are arranged on both sides of the plurality of semiconductor elements 21a, 22a (21b, 22b) in the width direction of the flow path, and the adjacent semiconductor elements 21a, 22a (21b, 22b). 22b). Therefore, the cooler 10 is less likely to deform even when pressurized in the stacking direction. In addition, since the reinforcing members 11, 12, and 13 are arranged such that the longitudinal direction is along the direction of the flow path (the direction in which the coolant flows), there is little increase in flow path resistance. The reinforcing members 11 , 12 , 13 are made of a material having higher rigidity than the material of the cooler 10 .

The reinforcing members 11, 12, 13 are arranged so as not to overlap the semiconductor elements 21a, 21b, 22a, 22b when viewed in the stacking direction. Thereby, the strength of the cooler 10 is improved without lowering the cooling performance of the power conversion device 2 .

Moreover, the reinforcing members 11 , 12 , 13 are separate members from the cooler 10 . Manufacturing is easier than when the reinforcement member is made by processing the outer plate of the cooler 10 .

Fins 15 are accommodated inside the cooler 10 . The fins 15 are shaped such that a cross-sectional view along the XZ plane is rectangular. As a result, the contact area between the refrigerant and the cooler 10 is increased, and the cooling performance of the power converter 2 is improved. The fins 15 are fixed to the cooler 10 by brazing.

In the power conversion device 2 of this embodiment, grease is applied between the cooler 10 and the insulating plate 5 and between the insulating plate 5 and the semiconductor module 20 . Due to repeated heat generation and cooling of the semiconductor module 20, the grease applied between the cooler 10 and the insulating plate 5 or between the insulating plate 5 and the semiconductor module 20 may flow out. Such a phenomenon is called a pump-out phenomenon. When the pump-out phenomenon occurs, the efficiency of heat transfer from the semiconductor module 20 to the cooler 10 may deteriorate, and the cooling performance of the power conversion device 2 may deteriorate.

As described above, in the power conversion device 2 of this embodiment, the reinforcing members 11, 12, and 13 improve the strength of the cooler 10. FIG. Therefore, since the power conversion device 2 can be pressed in the stacking direction with a larger pressure, the adhesion between the cooler 10, the insulating plate 5 and the semiconductor module 20 is improved. As a result, the pump-out phenomenon can be suppressed, and deterioration of the cooling performance of the power conversion device 2 can be prevented.

Although specific examples of the technology disclosed in this specification have been described above in detail, 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 in 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 techniques exemplified in this specification or drawings can simultaneously achieve a plurality of purposes, and achieving one of them has technical utility in itself.

2: Power converter 3a: Refrigerant inflow pipe 3b: Refrigerant discharge pipes 4a, 4b: Communicating pipe 5: Insulating plate 6: Leaf spring 10: Coolers 11, 12, 13: Reinforcing member 20: Semiconductor modules 21a, 21b, 22a , 22b: semiconductor elements 27a, 27b, 28a, 28b: radiator plate

Claims (1)

A plurality of coolers are arranged in a row, a semiconductor module containing a plurality of semiconductor elements is sandwiched between the adjacent coolers, and the coolers and the semiconductor modules are pressurized in their stacking direction. and grease is applied between the cooler and the semiconductor module ,
A flow path through which a coolant flows in a direction crossing the stacking direction is formed inside the cooler,
Inside the cooler, a plurality of reinforcing members extending along the direction of the flow path and in contact with both one surface of the cooler intersecting the stacking direction and the opposite side are arranged. and
Inside the semiconductor module, when viewed from the stacking direction, at least two semiconductor elements are arranged in a flow channel width direction that intersects with the flow channel direction,
The plurality of reinforcing members are arranged so as not to overlap with the semiconductor element when viewed from the stacking direction, and two of the reinforcing members are arranged on both sides of the row of the semiconductor elements in the flow channel width direction. and one disposed between two of said semiconductor elements,
Power converter.

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