Semiconductor module and electrical power conversion device

Abstract

Semiconductor module comprising: - a conductive base plate (1); - an insulating substrate (2) provided on an upper surface of the conductive base plate (1); - a conductive pattern (3a-3d) provided on the insulating substrate (2); - a plurality of semiconductor devices (4a - 4f, 5a - 5f) provided on the conductive pattern (3a - 3d); - a plurality of ribs (6) provided on a lower surface of the conductive base plate (1); - a heat-dissipating base plate (7) provided at tips of the plurality of fins (6); - a radiator (8) provided so as to surround the plurality of fins (6) and the heat-dissipating base plate (7), and having an inflow opening (9a) and an outflow opening (9b) provided in a bottom of the radiator (8); and - a partition wall (10) which separates a space surrounded by the cooler (8) and the heat-dissipating base plate (7) into an inflow-side space (11a) connected to the inflow opening (9a) and an outflow-side space (11b) connected to the outflow opening (9b), wherein: - a first slot (12a) is provided in a central portion of the heat-dissipating base plate (7), - second and third slots (12b, 12c) are provided on both sides of the heat-dissipating base plate (7) along a direction from an inflow side to an outflow side between the heat-dissipating base plate (7) and the cooler (8), and - the second and third slots (12b, 12c) are inflow-side slots connected to the inflow-side space (11a), and - the first slot (12a) is an outflow-side slot connected to the outflow-side space (11b).

Description

Area

[0001] The present invention relates to a semiconductor module with an integrated cooler and an electric power conversion device. background

[0002] Semiconductor modules are used for vehicle engine control and the like, and there is a continuing demand for size and weight reduction of such modules. To achieve size reduction, a structure for efficient cooling of semiconductor devices is essential. Therefore, the development of a direct cooling structure in which semiconductor devices are directly connected to cooling fins and directly cooled is being promoted.

[0003] A semiconductor module in which semiconductor devices are directly cooled with fins has been proposed (see, for example, PTL 1). However, since there are a total of three connecting holes, namely two inflow holes and one outflow hole, the assembly process can be complicated. Furthermore, cooling of the fins proceeds in a path connecting the inflow hole and the outflow hole; however, it is difficult for the cooling water to flow outside the path, and the cooling performance is reduced. As a result, more uniform cooling performance cannot be obtained.

[0004] A semiconductor module with an integrated cooler has also been proposed (see, for example, PTL 2). However, since cooling water impinges on fins without being divided, a long flow path is realized in one direction, and a large difference in cooling performance occurs between a device on the upstream side and a device on the downstream side.

[0005] Furthermore, a module with an integrated cooler in which cooling water is divided has also been proposed (see, for example, PTL 3). However, the cooling water jets directly impact the fins, generating dynamic pressure, and the fins are subjected to great stress. For this reason, high strength is required for the fins. An increase in pressure loss due to dynamic pressure generation is also a problem. Moreover, since a water flow in the flow path is greatly disturbed when water is jetted from a plurality of jet orifices, the process is difficult to control, and ultimately, a large difference in cooling performance occurs between the upstream and downstream sides. Citation listPatent literature [PTL 1] Japanese patent application JP 2016- 6 826 A [PTL 2] Japanese patent application JP S64- 71 156 A [PTL 3] Japanese patent application JP 2014- 82 311 A Summary

[0006] US 2014 / 0 251 582 A1 describes a heat exchanger system comprising a heat sink having a plurality of adjacent fins defining a corresponding plurality of microchannels between adjacent fins, with a countersunk groove extending transversely relative to the fins; a manifold body at least partially defining an opening generally overlying the groove.

[0007] DE 11 2015 007 145 T5 discloses a semiconductor device comprising a fin member 16 having a plurality of protruding parts connected to a lower surface of a heat transfer base plate 11, a cooling member 17 covering the fin member 16 and connected to an inlet 17a through which a coolant flowing toward the fin member 16 flows in and an outlet 17b through which a coolant flowing from the fin member 16 flows out, and a manifold 18 which is a water storage chamber provided between the inlet 17a and the fin member 16 and separated from the fin member 16 so as to allow a coolant to flow from the inlet 17a to the fin member 16. Technical problem

[0008] In the conventional integrated cooler module, the flow distribution at the time it flows to and from the fins is insufficient, and it is impossible to uniformly cool a plurality of semiconductor devices. For this reason, there is a difference in cooling performance between the upstream and downstream sides, and the thermal design of the module is limited by the temperature of the downstream semiconductor device. Since it is difficult to control the water flow and the pressure loss also increases, the allowable heat generation per unit volume of the module is also small. In addition, the structure is complicated, it is difficult to arrange the inlet and outlet ports on the bottom, and it is difficult to reduce the footprint.

[0009] The present invention has been made to solve the problems as described above, and an object of the present invention is to provide a semiconductor module and an electric power conversion device which have a simple structure and enable a plurality of semiconductor devices to be uniformly cooled, improve the allowable heat generation per unit volume of the module, and reduce the floor area. Solution to the problem

[0010] The object underlying the invention is achieved in a semiconductor module according to the invention with the features of claim 1 and in an electrical power conversion device according to the invention with the features of claim 9. Advantageous further developments are the subject of the respective dependent claims.

[0011] A semiconductor module according to the present invention comprises: a conductive base plate; an insulating substrate provided on an upper surface of the conductive base plate; a conductive pattern provided on the insulating substrate; a plurality of semiconductor devices provided on the conductive pattern; a plurality of fins provided on a lower surface of the conductive base plate; a heat-dissipating base plate provided at tips of the plurality of fins; a cooler provided so as to surround the plurality of fins and the heat-dissipating base plate, and having an inflow port and an outflow port provided on a lower surface of the cooler;and a partition wall that separates a space surrounded by the radiator and the heat-dissipating base plate into an inflow-side space connected to the inflow port and an outflow-side space connected to the outflow port, wherein a first slit is provided in a central portion of the heat-dissipating base plate, second and third slits are respectively provided on both sides of the heat-dissipating base plate along a direction from an inflow side to an outflow side between the heat-dissipating base plate and the radiator, the second and third slits are inflow-side slits connected to the inflow-side space, and the first slit is an outflow-side slit connected to the outflow-side space.; Advantageous effects of the invention

[0012] In the present invention, the inflow or outflow of cooling water to the plurality of cooling fins is divided by the first slot and the second and third slots. Therefore, it is possible to uniformly cool the plurality of semiconductor devices compared to unidirectional cooling. Moreover, the allowable heat generation per unit volume of the module can be increased. In addition, a simple structure has only one inflow port and one outflow port, and connection to a pump is simplified. Furthermore, the inflow port and the outflow port can be arranged on the bottom of the cooler, and the footprint can be reduced. Short description of the drawings Fig. 1 is a perspective view showing a semiconductor module according to Embodiment 1 of the present invention. Fig. 2 is a perspective view showing a disassembled state of the semiconductor module according to Embodiment 1 of the present invention. Fig. 3 is a plan view of the conductive base plate of the semiconductor module according to Embodiment 1 of the present invention. Fig. 4 is a bottom view of the conductive base plate of the semiconductor module according to Embodiment 1 of the present invention. Fig. 5 is a plan view of the heat dissipating base plate of the semiconductor module according to Embodiment 1 of the present invention. Fig. 6 is a plan view of the cooler of the semiconductor module according to Embodiment 1 of the present invention. Fig. 7 is a cross-sectional view taken along a line I-II of Fig. 1. Fig. 8 is a cross-sectional view taken along a line III-IV of Fig. 1. Fig. 9 is a diagram showing the cooling water flow in the semiconductor module according to Embodiment 1 of the present invention. Fig. 10 is a diagram showing the cooling water flow in the semiconductor module according to Embodiment 1 of the present invention. Fig. 11 is a diagram showing the cooling water flow in the semiconductor module according to Embodiment 1 of the present invention. Fig. 12 is a diagram showing the cooling water flow in the semiconductor module according to Embodiment 1 of the present invention. Fig. 13 is a diagram showing the cooling water flow in the semiconductor module according to Embodiment 1 of the present invention. Fig. 14 is a plan view to explain the difference in the flow path of the cooling water. Fig. 15 is a plan view to explain the difference in the flow path of the cooling water. Fig. 16 is a plan view to explain the difference in the flow path of the cooling water. Fig. 17 is a bottom view of the conductive base plate of the semiconductor module according to Embodiment 2 of the present invention. Fig. 18 is a bottom view of the conductive base plate of the semiconductor module according to Embodiment 3 of the present invention. Fig. 19 is a perspective view showing a semiconductor module according to Embodiment 4 of the present invention. Fig. 20 is a cross-sectional view taken along a line I-II of Fig. 19. Fig. 21 is a cross-sectional view taken along a line III-IV of Fig. 19. Fig. 22 is a block diagram illustrating a configuration of an electric power conversion system to which the electric power conversion device according to Embodiment 5 is applied. Description of embodiments

[0013] Referring to the drawings, a semiconductor module and an electric power conversion device according to embodiments of the present invention will be described. The same components are denoted by the same symbols, and repeated descriptions thereof may be omitted. Embodiment 1

[0014] Fig. 1 is a perspective view showing a semiconductor module according to Embodiment 1 of the present invention. Fig. 2 is a perspective view showing a disassembled state of the semiconductor module according to Embodiment 1 of the present invention. Fig. 3 is a plan view of the conductive base plate of the semiconductor module according to Embodiment 1 of the present invention. Fig. 4 is a bottom view of the conductive base plate of the semiconductor module according to Embodiment 1 of the present invention. Fig. 5 is a plan view of the heat dissipating base plate of the semiconductor module according to Embodiment 1 of the present invention. Fig. 6 is a plan view of the cooler of the semiconductor module according to Embodiment 1 of the present invention. Fig. 7 is a cross-sectional view taken along a line I-II of Fig. 1. Fig. 8 is a cross-sectional view taken along a line III-IV of Fig. 1. This semiconductor module is a module with an integrated cooler.

[0015] The conductive base plate 1 is made of Al or Cu and has a size of approximately 80 mm × 80 mm and a thickness of approximately 2 mm to 4 mm. An insulating substrate 2 with a conductive pattern made of Al or Cu bonded on both sides is bonded to the upper surface of the conductive base plate 1 by a bonding material such as solder or brazing. The insulating substrate 2 is made of AlN or Si3N4 and has a thickness of approximately 0.32 mm to 1 mm. To reduce thermal resistance, it is desirable to minimize the thickness of the insulating substrate 2.

[0016] A conductive pattern 3a to 3d is provided on the upper surface of the insulating substrate 2, and semiconductor devices 4a to 4f, 5a to 5f are bonded to the upper surface thereof by a bonding material. Here, semiconductor devices 4a to 4c, 5a to 5c are provided on the conductive pattern 3a, semiconductor devices 4d and 5d are provided on the conductive pattern 3b, semiconductor devices 4e and 5e are provided on the conductive pattern 3c, and semiconductor devices 4f and 5f are provided on the conductive pattern 3d. Semiconductor devices 4a to 4f are, for example, switching devices such as IGBTs or power MOSFETs, and semiconductor devices 5a to 5f are freewheeling diodes. In order to protect the semiconductor devices 4a to 4f, 5a to 5f, it is desirable to cover the upper surface of the conductive base plate 1 with a casing or a molding resin.

[0017] To improve cooling performance, a plurality of fins 6 are provided on the bottom surface of the conductive base plate 1. The plurality of fins 6 are pin fins, straight fins, or tapered fins. A heat-dissipating base plate 7 is brazed to the tips of the plurality of fins 6.

[0018] A radiator 8 is provided to surround the plurality of fins 6 and the heat-dissipating base plate 7. An inflow port 9a and an outflow port 9b are provided in the bottom of the radiator 8. A partition wall 10 separates the space surrounded by the radiator 8 and the heat-dissipating base plate 7 into an inflow-side space 11a connected to the inflow port 9a and an outflow-side space 11b connected to the outflow port 9b.

[0019] A first slit 12a extending in the upstream-to-downstream direction is provided in the central portion of the heat-dissipating base plate 7. Second and third slits 12b, 12c are respectively provided on both sides of the heat-dissipating base plate 7 along the upstream-to-downstream direction. The second and third slits 12b, 12c are upstream slits connected to the upstream space 11a, and the first slit 12a is an downstream slit connected to the downstream space 11b.

[0020] Fig. 9 to 13 are diagrams showing the cooling water flow in the semiconductor module according to Embodiment 1 of the present invention. Fig. 9 and Fig. 13 correspond to the top view of Fig. 6, Fig. 10 corresponds to the cross-sectional view of Fig. 7, and Fig. 11 and Fig. 12 correspond to the cross-sectional view of Fig. 8. The arrows in the figure represent the cooling water flow.

[0021] First fill, as in Fig. 9, the cooling water flowing from the inlet opening 9a enters the inlet-side space 11a. Next, as shown in Fig. 10, the cooling water 7 flows through the second and third slots 12b, 12c to the upper side of the heat-dissipating base plate 7. At this time, the water flows through the two slots are divided into mutually opposite directions. Next, as shown in Fig. 11, the water flows through the plurality of fins 6 in order from the outside to the center. Next, as shown in Fig. 12, the cooling water flows through the central first slot 12a into the outflow-side space 11b. Thereafter, as shown in Fig. 13, the cooling water is discharged through the outlet opening 9b.

[0022] As described above, in the present embodiment, the flow of cooling water to the plurality of fins 6 is divided by the first slit 12a and the second and third slits 12b, 12c. The cooling water flowing from the inflow port 9a is divided by the second and third slits 12b, 12c to cool the plurality of fins 6 from both sides. Therefore, it is possible to uniformly cool the plurality of semiconductor devices 4a to 4f, 5a to 5f compared to unidirectional cooling. Furthermore, the allowable heat generation per unit volume of the module can be increased. In addition, a simple structure has only one inflow port 9a and one outflow port 9b, and connection to a pump is simplified. Furthermore, the inflow port and the outflow port can be arranged on the bottom of the cooler 8, and the footprint can be reduced.

[0023] Furthermore, the device is preferentially cooled on the upstream slot into which cooling water flows. Therefore, the semiconductor devices 4a to 4f having a larger calorific value than the semiconductor devices 5a to 5f are arranged closer to the upstream slot than the semiconductor devices 5a to 5f. That is, the semiconductor devices 4a to 4f are arranged above the second and third slots 12b, 12c on the outer side of the heat-dissipating base plate 7. As a result, since the semiconductor devices 4a to 4f having a large calorific value are preferentially cooled, the entire module can be efficiently cooled, and the temperature rise can be suppressed.

[0024] Fig. 14 to 16 are top views to explain the difference in the flow path of the cooling water. If the cooling water is arranged as in Fig. 14, the group of semiconductor devices 4a to 4c with a large calorific value is preferentially and uniformly cooled; but the group of semiconductor devices 4d to 4f with a large calorific value is not preferentially cooled. If the cooling water is arranged as in Fig. 15, both device groups are neither preferentially nor evenly cooled. In the present embodiment, as shown in Fig. 16, since the cooling water flows from both ends to the center, both device groups are preferentially and evenly cooled.

[0025] The first slot 12a may be the upstream slot, and the second and third slots 12b, 12c may be the downstream slots. In this case, the cooling water flowing in from the inflow port 9a of the cooler 8 is introduced into the plurality of fins 6 through a first slot 12a and discharged from the plurality of fins 6 to the cooler 8 through the second and third slots 12b, 12c. Therefore, by disposing the semiconductor devices 4a to 4f with a large calorific value above the first slot 12 at the center of the heat-dissipating base plate 7, the semiconductor devices 4a to 4f can be preferentially cooled. Embodiment 2

[0026] Fig. 17 is a bottom view of the conductive base plate of the semiconductor module according to Embodiment 2 of the present invention. Of the plurality of fins 6, the upstream fins have a higher fin density than the downstream fins. Therefore, this shape makes it more difficult for the cooling water to pass through the upstream fins, where the water flow is strong, than through the downstream fins, where the water flow is weak. As a result, it is possible to prevent the cooling water from concentrating on the upstream fins, increase the inflow to the downstream fins, and ensure a uniform amount of cooling water passing through all the fins, thereby enabling uniform cooling. Embodiment 3

[0027] Fig. 18 is a bottom view of the conductive base plate of the semiconductor module according to Embodiment 3 of the present invention. The shape of the plurality of fins 6 is a radial elliptical arc with a center on the upstream side. Since this shape also makes it more difficult for cooling water to pass through the upstream fins than the downstream fins, the same effect as in Embodiment 2 can be obtained in this case. Embodiment 4

[0028] Fig. 19 is a perspective view showing a semiconductor module according to Embodiment 4 of the present invention. Fig. 20 is a cross-sectional view taken along a line I-II of Fig. 19. Fig. 21 is a cross-sectional view taken along a line III-IV of Fig. 19. Here, a blow-by structure 13 is provided above the inlet opening 9a and the outlet opening 9b, which structure 13 lacks the plurality of fins 6 and the heat-dissipating base plate 7. The volume of space around the inlet opening 9a and the outlet opening 9b is enlarged by the blow-by structure 13 so that it becomes a portion of a water reservoir, thus reducing the pressure loss in the module.

[0029] In Embodiments 1 to 4, the semiconductor devices 4a to 4f, 5a to 5f are not limited to semiconductor devices formed of silicon, but may instead be formed of a wide-bandgap semiconductor having a wider bandgap than that of silicon. The wide-bandgap semiconductor is, for example, a silicon carbide, a gallium nitride-based material, or diamond. A semiconductor device formed of such a wide-bandgap semiconductor has high withstand voltage and high allowable current density and can thus be miniaturized. The use of such a miniaturized semiconductor device enables miniaturization and high integration of the semiconductor module in which the semiconductor device is integrated.Furthermore, since the semiconductor device has high heat resistance, a radiating fin of a heat sink can be miniaturized, and a water-cooled part can be air-cooled, leading to further miniaturization of the semiconductor module. Furthermore, since the semiconductor device has low power loss and high efficiency, a high-efficiency semiconductor module can be achieved. Embodiment 5

[0030] In this embodiment, the semiconductor modules according to Embodiments 1 to 4 described above are applied to an electric power conversion device. For example, the electric power conversion device is an inverter device, a converter device, a servo amplifier, or a power supply unit. Although the present invention is not limited to a specific electric power conversion device, a case where the present invention is applied to a three-phase inverter will be described below.

[0031] Fig.22 is a block diagram illustrating a configuration of an electric power conversion system to which the electric power conversion device according to Embodiment 5 is applied. This electric power conversion system includes a power supply 100, an electric power conversion device 200, and a load 300. The power supply 100 is a DC power supply and supplies DC power to the electric power conversion device 200. The power supply 100 may be composed of various components. For example, the power supply 100 may be composed of a DC system, a solar cell, or a storage battery, or may be composed of a rectifier or an AC / DC converter connected to an AC system. Alternatively, the power supply 100 may be composed of a DC / DC converter that converts DC power output from a DC system into a predetermined power.

[0032] The electric power conversion device 200 is a three-phase inverter connected to a node between the power supply 100 and the load 300, converts DC power supplied by the power supply 100 into AC power, and supplies the AC power to the load 300. The electric power conversion device 200 includes a main conversion circuit 201 that converts DC power into AC power and outputs the AC power, and a control circuit 203 that outputs a control signal for controlling the main conversion circuit 201 to the main conversion circuit 201.

[0033] The load 300 is a three-phase electric motor driven by AC power provided by the electrical power conversion device 200. The load 300 is not limited to a specific application. The load is used as an electric motor mounted on various electrical devices, such as an electric motor for, for example, a hybrid vehicle, an electric vehicle, a rail vehicle, an elevator, or an air conditioner.

[0034] The electrical power conversion device 200 will be described in detail below. The main conversion circuit 201 includes a switching device and a reflux diode (not illustrated). When the switching device is switched, the main conversion circuit 201 converts DC power supplied from the power supply 100 into AC power and supplies the AC power to the load 300. The main conversion circuit 201 may have various types of specific circuit configurations. The main conversion circuit 201 according to this embodiment is a three-phase, two-level full-bridge circuit, which may be composed of six switching devices and six reflux diodes connected in anti-parallel to the respective switching devices. Each switching device and each reflux diode of the main conversion circuit 201 is composed of a semiconductor device 202 corresponding to Embodiments 1 to 4 described above.Two switching devices of the six switching devices are connected in series to form a vertical arm. Each vertical arm forms one phase (U-phase, V-phase, W-phase) of the full-bridge circuit. The output terminals of each vertical arm, i.e., three output terminals of the main conversion circuit 201, are connected to the load 300.

[0035] The main conversion circuit 201 further includes a drive circuit (not shown) that drives each switching device. The drive circuit may be integrated into the semiconductor device 202. Another drive circuit different from the semiconductor device 202 may be provided. The drive circuit generates a drive signal for driving each switching device of the main conversion circuit 201 and supplies the generated drive signal to a control electrode of each switching device of the main conversion circuit 201. Specifically, the drive circuit outputs, to the control electrode of each switching device, a drive signal for turning on each switching device and a drive signal for turning off each switching device according to the control signal output from the control circuit 203, which will be described later.When the ON state of each switching device is maintained, the drive signal is a voltage signal (ON signal) with a voltage equal to or higher than the threshold voltage of the switching device. When the OFF state of each switching device is maintained, the drive signal is a voltage signal (OFF signal) with a voltage equal to or lower than the threshold voltage of the switching device.

[0036] The control circuit 203 controls each switching device of the main conversion circuit 201 to supply a desired power to the load 300. Specifically, the control circuit 203 calculates a period (ON period) in which each switching device of the main conversion circuit 201 is in the ON state based on the power to be supplied to the load 300. For example, the main conversion circuit 201 can be controlled by PWM control to modulate the ON period of each switching device depending on the voltage to be output. Further, the control circuit 203 outputs a control command (control signal) to the drive circuit included in the main conversion circuit 201 so that, at each time point, the ON signal is output to each switching device to be turned on and an OFF signal is output to each switching device to be turned off.The drive circuit outputs the ON signal or OFF signal as the drive signal to the control electrode of each switching device according to the control signal.

[0037] In the electric power conversion device according to this embodiment, the semiconductor modules according to Embodiments 1 to 4 are used as the switching devices and the flyback diodes of the main conversion circuit 201. Therefore, miniaturization can be realized.

[0038] Although this embodiment illustrates an example in which the present invention is applied to a three-phase two-level inverter, the present invention is not limited to this and can be applied to various power conversion devices. While this embodiment illustrates a two-level electric power conversion device, the present invention can also be applied to an electric power conversion device having three or more levels. When power is supplied to a single-phase load, the present invention can be applied to a single-phase inverter. The present invention can also be applied to a DC / DC converter or an AC / DC converter when power is supplied to a DC load or the like.

[0039] Furthermore, in the electric power conversion device to which the present invention is applied, the above-mentioned load is not limited to an electric motor. For example, the load can also be used as a power supply device for an electric discharge machine, a laser beam machine, an induction heating cooking device, or a non-contact power supply system of an appliance. Alternatively, the electric power conversion device can be used as a power conditioner for a photovoltaic power generation system, an electricity storage system, or the like. List of reference symbols

[0040] 1 conductive base plate; 2 insulating substrate; 3a to 3d conductive pattern; 4a to 4f, 5a to 5f semiconductor device; 6 fin; 7 heat-dissipating base plate; 8 cooler; 9a inlet port; 9b outlet port; 10 partition wall; 11a inlet space; 11b outlet space; 12a first slot; 12b second slot; 12c third slot; 13 blow-by structure; 201 main conversion circuit; 203 control circuit

Claims

[1] Semiconductor module comprising: - a conductive base plate (1); - an insulating substrate (2) provided on an upper surface of the conductive base plate (1); - a conductive pattern (3a-3d) provided on the insulating substrate (2); - a plurality of semiconductor devices (4a - 4f, 5a - 5f) provided on the conductive pattern (3a - 3d); - a plurality of ribs (6) provided on a lower surface of the conductive base plate (1); - a heat-dissipating base plate (7) provided at tips of the plurality of fins (6); - a radiator (8) provided so as to surround the plurality of fins (6) and the heat-dissipating base plate (7), and having an inflow opening (9a) and an outflow opening (9b) provided in a bottom of the radiator (8); and - a partition wall (10) which separates a space surrounded by the cooler (8) and the heat-dissipating base plate (7) into an inflow-side space (11a) connected to the inflow opening (9a) and an outflow-side space (11b) connected to the outflow opening (9b), wherein: - a first slot (12a) is provided in a central portion of the heat-dissipating base plate (7), - second and third slots (12b, 12c) are provided on both sides of the heat-dissipating base plate (7) along a direction from an inflow side to an outflow side between the heat-dissipating base plate (7) and the cooler (8), and - the second and third slots (12b, 12c) are inflow-side slots connected to the inflow-side space (11a), and - the first slot (12a) is an outflow-side slot connected to the outflow-side space (11b). [2] A semiconductor module according to claim 1, wherein: - the plurality of semiconductor devices (4a - 4f, 5a - 5f) comprises a first semiconductor device (5a - 5f) and a second semiconductor device (4a - 4f) having a larger calorific value than the first semiconductor device (5a - 5f), and - the second semiconductor device (4a - 4f) is arranged closer to the inflow-side slot than the first semiconductor device (5a - 5f). [3] A semiconductor module according to claim 2, wherein the second semiconductor device (4a-4f) is arranged above the second and third slots (12b, 12c). [4] A semiconductor module according to any one of the preceding claims, wherein an upstream fin (6) as part of the plurality of fins (6) has a shape that makes it more difficult for the cooling water to pass through the upstream fin (6) than through an downstream fin (6). [5] The semiconductor module according to claim 4, wherein the inflow-side fins (6) have a higher density of fins (6) than the outflow-side fins (6). [6] The semiconductor module according to claim 4, wherein a shape of the plurality of ribs (6) is a radial elliptical arc having a center on the upstream side. [7] A semiconductor module according to any one of the preceding claims, wherein a blow-by structure (13) not including the plurality of fins (6) and the heat-dissipating base plate (7) is provided above the inflow opening (9a) and the outflow opening (9b). [8] A semiconductor module according to any one of the preceding claims, wherein the plurality of semiconductor devices (4a - 4f, 5a - 5f) are made of a wide band gap semiconductor. [9] An electrical power conversion device comprising: - a main conversion circuit (201) containing a semiconductor module according to any one of the preceding claims 1 to 9 and arranged to convert input power and output converted power; and - a control circuit (203) configured to output a control signal for controlling the main conversion circuit (201) to the main conversion circuit (201).

Images