Inverter and electric vehicle

Abstract

The purpose of the present disclosure is to reduce the total loss of an inverter that includes a Si switching element and a SiC switching element which are connected in parallel. An inverter (101) comprises: a SiC MOSFET module (1); a Si IGBT module (2) connected in parallel to the SiC MOSFET module (1); a SiC MOSFET module control circuit (7) that controls the SiC MOSFET module (1); and a Si IGBT module control circuit (8) that controls the Si IGBT module (2). The SiC MOSFET module control circuit (7) stops the driving of the SiC MOSFET module (1) when the element temperature of the SiC MOSFET module (1) is higher than a first threshold value. The Si IGBT module control circuit (8) stops the driving of the Si IGBT module (2) when the element temperature of the Si IGBT module (2) is higher than a second threshold value.

Description

[Technical field]

[0001] The present disclosure relates to an inverter and an electric vehicle. [Background technology]

[0002] Patent Document 1 discloses a power conversion device as an inverter for use in an electric vehicle, which includes a Si switching element and a SiC switching element connected in parallel between a power source and a load, and a controller that selectively drives one of the switching elements. The controller drives only the SiC switching element when the current is low. The controller also drives the Si switching element preferentially when the current is high, and drives the SiC switching element instead of the Si switching element when the Si switching element becomes hot. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-092505 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the low current region, the SiC switching element has lower loss than the Si switching element, and in the high current region, the Si switching element has lower loss than the SiC switching element. According to the power conversion device of Patent Document 1, the switching element with the smaller loss is selected and driven according to the current, but since only one is selectively driven, it is difficult to reduce the total loss.

[0005] The present disclosure has been made to solve the above problems, and has an object to reduce the total loss in an inverter including Si switching elements and SiC switching elements connected in parallel. [Means for solving the problem]

[0006] The inverter of the present disclosure includes a SiC MOSFET module including a plurality of SiC MOSFETs, a Si IGBT module including a plurality of Si IGBTs connected in parallel to the SiC MOSFET module, a control circuit for the SiC MOSFET module that controls the SiC MOSFET module 1, and a control circuit for the Si IGBT module that controls the Si IGBT module. The control circuit for the SiC MOSFET module stops driving the SiC MOSFET module when the element temperature of the SiC MOSFET module is higher than a predetermined first threshold. The control circuit for the Si IGBT module stops driving the Si IGBT module when the element temperature of the Si IGBT module is higher than a predetermined second threshold. When the element temperature of the SiC MOSFET module is equal to or lower than the first threshold and the element temperature of the Si IGBT module is equal to or lower than the second threshold, the control circuit for the SiC MOSFET module drives the SiC MOSFET module and the control circuit for the Si IGBT module drives the Si IGBT module. The control circuit for the Si IGBT module reduces the output of the Si IGBT module when the element temperature of the SiC MOSFET module is higher than a first threshold value, compared to when the element temperature of the SiC MOSFET module is equal to or lower than the first threshold value, and the control circuit for the SiC MOSFET module reduces the output of the SiC MOSFET module when the element temperature of the Si IGBT module is higher than a second threshold value, compared to when the element temperature of the Si IGBT module is equal to or lower than the second threshold value. do. Effect of the Invention

[0007] According to the inverter of the present disclosure, the total loss is reduced.Objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings. [Brief description of the drawings]

[0008] [Figure 1] 1 is a circuit diagram showing a state in which an inverter according to a first embodiment is connected to a battery, a capacitor, and a motor. [Diagram 2] FIG. 1 is a diagram showing the current-voltage characteristics of a SiC MOSFET and a Si IGBT. [Diagram 3] FIG. 1 is a graph showing typical current-voltage characteristics of a SiC MOSFET at 25° C. and 150° C. [Figure 4] 1 is a diagram showing typical current-voltage characteristics of a Si IGBT at 25° C. and 150° C. [Diagram 5] It is a diagram showing a state in which a SiC MOSFET module and a Si IGBT module are mounted on the cooler according to Embodiment 1. [Figure 6] It is a diagram showing a state in which a SiC MOSFET module and a Si IGBT module are mounted on the cooler according to Embodiment 2. [Figure 7] It is a diagram showing a state in which a SiC MOSFET module and a Si IGBT module are mounted on the cooler according to Embodiment 3.

Embodiments for Carrying Out the Invention

[0009] <A. Embodiment 1> <A-1. Configuration> FIG. 1 is a circuit diagram showing a state in which the inverter 101 according to Embodiment 1 is connected to the battery 4, the capacitor 5, and the motor 6.

[0010] The motor 6 is a motor of an electric vehicle such as an electric vehicle or a hybrid vehicle.

[0011] The inverter 101 is configured to include a SiC MOSFET module 1, a Si IGBT module 2, a control circuit 7 for the SiC MOSFET module, a control circuit 8 for the Si IGBT module, and an inverter control circuit 9.

[0012] The SiC MOSFET module 1 includes a plurality of SiC MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). In FIG. 1, the SiC MOSFET module 1 includes six SiC MOSFETs 11-16. The SiC MOSFET 11 is the upper arm of the U phase, the SiC MOSFET 12 is the lower arm of the U phase, the SiC MOSFET 13 is the upper arm of the V phase, the SiC MOSFET 14 is the lower arm of the V phase, the SiC MOSFET 15 is the upper arm of the W phase, and the SiC MOSFET 16 is the lower arm of the W phase.

[0013] The Si IGBT module 2 includes a plurality of Si IGBTs (Insulated Gate Bipolar Transistors). In Fig. 1, the Si IGBT module 2 includes six Si IGBTs 21-26 and freewheel diodes 27-32 connected in parallel to the Si IGBTs 21-26, respectively. The Si IGBT 21 is a U-phase upper arm, the Si IGBT 22 is a U-phase lower arm, the Si IGBT 23 is a V-phase upper arm, the Si IGBT 24 is a V-phase lower arm, the Si IGBT 25 is a W-phase upper arm, and the Si IGBT 26 is a W-phase lower arm.

[0014] The P-terminal, N-terminal, U-terminal, V-terminal and W-terminals which are main terminals of the SiC MOSFET module 1 are connected in parallel to the P-terminal, N-terminal, U-terminal, V-terminal and W-terminals which are main terminals of the Si IGBT module 2. The U-terminal, V-terminal and W-terminals of the SiC MOSFET module 1 and the Si IGBT module 2 are connected to a motor 6, and the P-terminal and N-terminal are connected to a battery 4 and a capacitor 5.

[0015] The SiC MOSFET module control circuit 7 is a control circuit for the SiC MOSFET module 1. Signal terminals such as the gate terminals of each of the SiC MOSFETs 11-16 in the SiC MOSFET module 1 are connected to the SiC MOSFET module control circuit 7.

[0016] The Si IGBT module control circuit 8 is a control circuit for the Si IGBT module 2. Signal terminals such as the gate terminals of each of the Si IGBTs 21-26 in the Si IGBT module 2 are connected to the Si IGBT module control circuit 8.

[0017] The SiC MOSFET module control circuit 7 and the Si IGBT module control circuit 8 are connected to an inverter control circuit 9.

[0018] In Fig. 1, as the configuration of the Si IGBT module 2, Si IGBTs 21 - 26 and free - wheel diodes 27 - 32 connected in parallel with each of the Si IGBTs 21 - 26 are shown. The free - wheel diodes 27 - 32 may be composed of free - wheel diode elements separate from the IGBT elements constituting the Si IGBTs 21 - 26. Alternatively, the Si IGBTs 21 - 26 and the free - wheel diodes 27 - 32 may be composed of RC - IGBT elements incorporating free - wheel diodes.

[0019] Also, in Fig. 1, only the gate terminals are shown as the signal terminals of the SiC MOSFETs 11 - 16 and the Si IGBTs 21 - 26. However, the SiC MOSFETs 11 - 16 and the Si IGBTs 21 - 26 may be provided with current sense terminals, temperature sense terminals, and collector sense terminals. Also, the SiC MOSFETs 11 - 16 may be provided with source sense terminals. Also, the Si IGBTs 21 - 26 may be provided with emitter sense terminals.

[0020] <A - 2. Operation> The control circuit 7 for the SiC MOSFET module receives a PWM signal from the inverter control circuit 9 and switches the SiC MOSFET module 1. As a result, the DC current input to the SiC MOSFET module 1 from the battery 4 or the capacitor 5 via the P terminal and the N terminal is output as three - phase AC to the motor 6 via the U terminal, the V terminal, and the W terminal.

[0021] Similarly, the control circuit 8 for the Si IGBT module receives a PWM signal from the inverter control circuit 9 and switches the Si IGBT module 2. As a result, the DC current input to the Si IGBT module 2 from the battery 4 or the capacitor 5 via the P terminal and the N terminal is output as three - phase AC to the motor 6 via the U terminal, the V terminal, and the W terminal.

[0022] The SiC MOSFET module control circuit 7 monitors the element temperature of the SiC MOSFET module 1, and when the element temperature becomes higher than a predetermined first threshold, it cuts off the input signal to the gate of the SiC MOSFET module 1. At this time, only the Si IGBT module 2 drives the motor 6. At the same time, the SiC MOSFET module control circuit 7 outputs a signal to the inverter control circuit 9 indicating that the element temperature of the SiC MOSFET module 1 has become higher than the first threshold. When the inverter control circuit 9 receives the signal indicating that the element temperature of the SiC MOSFET module 1 has become higher than the first threshold, it outputs a signal to the Si IGBT module control circuit 8 instructing it to suppress the output of the Si IGBT module 2. Then, the Si IGBT module control circuit 8 suppresses the output of the Si IGBT module 2. This suppresses the temperature rise of the Si IGBT module 2, which is driven independently.

[0023] Similarly, the Si IGBT module control circuit 8 also monitors the element temperature of the Si IGBT module 2, and cuts off the input signal to the gate of the Si IGBT module 2 when the element temperature becomes higher than a predetermined second threshold. At this time, only the SiC MOSFET module 1 drives the motor 6. At the same time, the Si IGBT module control circuit 8 outputs a signal to the inverter control circuit 9 indicating that the element temperature of the Si IGBT module 2 has become higher than the second threshold. When the inverter control circuit 9 receives the signal indicating that the element temperature of the Si IGBT module 2 has become higher than the second threshold, it outputs a signal to the SiC MOSFET module control circuit 7 instructing it to suppress the output of the SiC MOSFET module 1. Then, the SiC MOSFET module control circuit 7 suppresses the output of the SiC MOSFET module 1. This suppresses the temperature rise of the Si IGBT module 2, which is driven independently.

[0024] When the element temperature of the SiC MOSFET module 1 is equal to or lower than the first threshold and the element temperature of the Si IGBT module 2 is equal to or lower than the second threshold, both the SiC MOSFET module 1 and the Si IGBT module 2 are driven.

[0025] The SiC MOSFET module 1 and the Si IGBT module 2 have different cooling and heat generation states and different heat resistance performances. Therefore, the element temperature threshold value at which the above-mentioned input signal is cut off differs between the SiC MOSFET module 1 and the Si IGBT module 2.

[0026] Heat generated in the SiC MOSFETs 11-16 and the Si IGBTs 21-26 is dissipated through the die bond joints that mount these elements. The die bond joints are prone to cracking due to the thermal cycles caused by turning the elements on and off. Normally, when cracks occur, the heat dissipation performance deteriorates, the temperature of the elements is likely to rise, and the cracks progress. However, in the inverter 101 of this embodiment, the SiC MOSFET module control circuit 7 and the Si IGBT module control circuit 8 monitor the element temperatures of the SiC MOSFETs 11-16 and the Si IGBTs 21-26 as described above, and stop driving the elements when the element temperature reaches a threshold value, so that the progression of cracks in the die bond joints can be delayed.

[0027] Figure 2 shows the current-voltage characteristics of a SiC MOSFET and a Si IGBT. When a current is passed through a SiC MOSFET or a Si IGBT, losses occur due to the resistance components of each. However, as shown in Figure 2, the two have different characteristics with respect to current. Specifically, in the low current range, the SiC MOSFET has a lower voltage, i.e., a lower resistance, and in the high current range, the Si IGBT has a lower voltage, i.e., a lower resistance. When a SiC MOSFET and a Si IGBT are connected in parallel, more current flows into the side with the lower resistance.

[0028] In Patent Document 1, it is proposed to utilize this characteristic to selectively drive the SiC MOSFET in the low current region and the Si IGBT in the high current region. However, in either the low current region or the high current region, driving both reduces the total loss of the inverter.

[0029] Figure 3 shows typical current-voltage characteristics of a SiC MOSFET at 25°C and 150°C. Figure 4 shows typical current-voltage characteristics of a Si IGBT at 25°C and 150°C.

[0030] As shown in Figure 3, the voltage of a SiC MOSFET rises dramatically at high temperatures compared to low temperatures. As shown in Figure 4, a Si IGBT has a lower voltage at high temperatures in the low current range, and in the high current range, the reverse occurs, with a lower voltage at low temperatures, but the difference is not as large as that of a SiC MOSFET. As such, each element generates heat due to its resistance component when current is applied, so the module needs to be cooled efficiently by a cooler.

[0031] 5 shows a state in which the SiC MOSFET module 1 and the Si IGBT module 2 are mounted on a cooler 30. That is, the inverter 101 of the present embodiment includes the cooler 30.

[0032] The cooler 30 is configured to include a housing 32, a water inlet pipe 33, and a water outlet pipe 34. The housing 32 includes a top plate 35, on which the SiC MOSFET module 1 and the Si IGBT module 2 are mounted. The area of ​​the top plate 35 on which the SiC MOSFET module 1 is mounted is referred to as a first area 351, and the area on which the Si IGBT module 2 is mounted is referred to as a second area 352. The cooling water taken into the housing 32 from the water inlet pipe 33 cools the SiC MOSFET module 1 and the Si IGBT module 2 while flowing through the housing 32, and exits from the water outlet pipe 34. In this manner, the flow path of the cooling water is present within the housing 32, as indicated by the dashed arrows in FIG. 5.

[0033] As shown in Fig. 5, the SiC MOSFET module 1 is mounted upstream of the Si IGBT module 2 in the cooling water flow path. That is, the first region 351 is located upstream of the second region 352 in the cooling water flow path.

[0034] With such a configuration, the cooling water that enters the housing 32 from the water inlet pipe 33 first cools the SiC MOSFET module 1, and then cools the Si IGBT module 2 and exits from the water outlet pipe 34. Since the cooling water flows through the cooler 30 while taking away the heat of each module, the SiC MOSFET module 1 upstream is cooled with higher cooling performance than the Si IGBT module 2 downstream.

[0035] As shown in Figs. 3 and 4, the SiC MOSFET generates more heat at high temperatures than the Si IGBT. Therefore, by arranging the SiC MOSFET module 1 at a position with higher cooling performance in the cooler 30 than the Si IGBT module 2, the total loss of the inverter 101 can be suppressed.

[0036] <A-3. Effect> The inverter 101 according to the first embodiment includes a SiC MOSFET module 1 including a plurality of SiC MOSFETs 11-16, a Si IGBT module 2 including a plurality of Si IGBTs 21-26 connected in parallel to the SiC MOSFET module 1, a SiC MOSFET module control circuit 7 that controls the SiC MOSFET module 1, and a Si IGBT module control circuit 8 that controls the Si IGBT module 2. The SiC MOSFET module control circuit 7 stops driving the SiC MOSFET module 1 when the element temperature of the SiC MOSFET module 1 is higher than a predetermined first threshold. The Si IGBT module control circuit 8 stops driving the Si IGBT module 2 when the element temperature of the Si IGBT module 2 is higher than a predetermined second threshold. When the element temperature of the SiC MOSFET module 1 is equal to or lower than a first threshold value and the element temperature of the Si IGBT module 2 is equal to or lower than a second threshold value, the control circuit 7 for the SiC MOSFET module drives the SiC MOSFET module 1 and the control circuit 8 for the Si IGBT module drives the Si IGBT module 2.

[0037] According to the above configuration, if the element temperature is not high, both the SiC MOSFET module 1 and the Si IGBT module 2 drive the motor 6, and therefore the total loss of the inverter 101 is reduced compared to the case where only one of the modules drives the motor 6.

[0038] Also, when the element temperature of the SiC MOSFET module 1 is higher than the first threshold value, the control circuit 8 for the Si IGBT module reduces the output of the Si IGBT module 2 compared to the case where the element temperature of the SiC MOSFET module 1 is equal to or lower than the first threshold value. When the element temperature of the Si IGBT module 2 is higher than the second threshold value, the control circuit 7 for the SiC MOSFET module reduces the output of the SiC MOSFET module 1 compared to the case where the element temperature of the Si IGBT module 2 is equal to or lower than the second threshold value. Therefore, destruction of the switching element in the SiC MOSFET module 1 or the Si IGBT module 2 operating alone can be prevented.

[0039] The inverter 101 according to Embodiment 1 further includes a cooler 30 on which the SiC MOSFET module 1 and the Si IGBT module 2 are mounted. The cooling performance of the cooler 30 at the mounting position of the SiC MOSFET module 1 is higher than the cooling performance of the cooler 30 at the mounting position of the Si IGBT module 2. As a result, since the SiC MOSFET module 1 with a large heat generation amount at high temperatures is preferentially cooled over the Si IGBT module 2, the total loss of the inverter 101 can be suppressed.

[0040] The cooler 30 includes a housing 32, a water inlet pipe 33 for taking in cooling water into the housing 32, and a water outlet pipe 34 for discharging the cooling water from the housing 32. The housing 32 includes a first region 351 on which the SiC MOSFET module 1 is mounted and a second region 352 on which the Si IGBT module 2 is mounted. The first region 351 is located upstream of the flow path of the cooling water from the water inlet pipe 33 to the water outlet pipe 34 compared to the second region 352. Therefore, the cooling water taken into the cooler 30 from the water inlet pipe 33 dissipates heat from the SiC MOSFET module 1 before the Si IGBT module 2. As a result, since the SiC MOSFET with a large heat generation amount at high temperatures is preferentially cooled over the Si IGBT, the total loss of the inverter 101 can be suppressed.

[0041] <B. Embodiment 2> <B-1. Configuration> The circuit configuration of the inverter 102 according to Embodiment 2 is as shown in FIG. 1, which is the same as that of the inverter 101 according to Embodiment 1. The inverter 102 includes a cooler 30A instead of the cooler 30 as compared with the inverter 101 according to Embodiment 1.

[0042] FIG. 6 shows a state in which the SiC MOSFET module 1 and the Si IGBT module 2 are mounted on the top plate 35 of the cooler 30A. The point that the SiC MOSFET module 1 is arranged upstream of the Si IGBT module 2 in the cooling water flow path is the same as that in Embodiment 1.

[0043] On the top plate 35 of the cooler 30A, the first region 351 is thicker than the second region 352. That is, the first region 351 has a larger heat capacity and higher cooling performance than the second region 352. The configuration of the cooler 30A other than the thickness of the top plate 35 is the same as that of the cooler 30 according to Embodiment 1.

[0044] When the electric vehicle using the inverter 102 accelerates suddenly such as during overtaking, the load temporarily increases. At this time, a large current flows through the SiC MOSFET module 1 with a small resistance value, and the heat generation amount instantaneously increases. However, according to the inverter 102, since the heat of the SiC MOSFET module 1 can be added to the cooling water of the cooler 30A and dissipated to the first region 351 of the top plate 35 with a high heat capacity, the rise in the element temperature in the SiC MOSFET module 1 can be suppressed.

[0045] <B-2. Effect> The housing 32 of the cooler 30A included in the inverter 102 according to Embodiment 2 includes a first region 351 on which the SiC MOSFET module 1 is mounted and a second region 352 on which the Si IGBT module 2 is mounted. The first region 351 is thicker than the second region 352. Therefore, since the cooling performance of the SiC MOSFET module 1 with a large heat generation amount at high temperatures is improved, the total loss of the inverter 102 can be suppressed.

[0046] <C. Embodiment 3> <C-1. Configuration> The circuit configuration of the inverter 103 according to Embodiment 3 is the same as that shown in FIG. 1 and is the same as the inverter 101 according to Embodiment 1. The inverter 103 includes a cooler 30B instead of the cooler 30 as compared with the inverter 101 according to Embodiment 1.

[0047] FIG. 7 shows a state where the SiC MOSFET module 1 and the Si IGBT module 2 are mounted on the top plate 35 of the cooler 30B. In FIG. 7, in order to show an image of the fins inside the cooler 30B, the outer frame portion excluding the top plate 35 of the cooler 30B is shown by a broken line. The point that the SiC MOSFET module 1 is arranged on the upstream side in the cooling water flow path than the Si IGBT module 2 is the same as in Embodiment 1.

[0048] The cooler 30B is different from the cooler 30 according to Embodiment 1 in that it includes a plurality of first fins 361 protruding from the first region 351 of the top plate 35 into the cooler 30B and a plurality of second fins 362 protruding from the second region 352 of the top plate 35 into the cooler 30B. In FIG. 7, the first fins 361 and the second fins 362 are pin fins, but fins of other shapes may also be used.

[0049] The cooling capacity and water flow resistance of the fins of the cooler vary depending on the shape of the fins. When the arrangement of the fins becomes dense, the contact area between the fins and the cooling water increases, thereby improving the heat exchange efficiency. On the other hand, the water flow resistance increases, resulting in a decrease in the flow rate of the cooling water.

[0050] In this regard, in the cooler 30B of the present embodiment, in the cooling water flow path from the water inlet pipe 33 to the water outlet pipe 34, the plurality of first fins 361 and the plurality of second fins 362 are arranged in series. And the arrangement density of the plurality of first fins 361 in the first region 351 is larger than the arrangement density of the plurality of second fins 362 in the second region 352. In other words, the plurality of first fins 361 are arranged densely, and the plurality of second fins 362 are arranged sparsely.

[0051] With such a configuration, it is possible to efficiently cool the SiC MOSFET module 1 while suppressing an increase in water flow resistance as compared with the case where all fins are densely arranged.

[0052] <C-2. Effect> The housing 32 of the cooler 30B included in the inverter 103 according to Embodiment 3 includes a first region 351 on which the SiC MOSFET module 1 is mounted and a second region 352 on which the Si IGBT module 2 is mounted. The cooler 30B includes a plurality of first fins 361 protruding from the first region 351 into the water flow path of the cooling water and a plurality of second fins 362 protruding from the second region 352 into the water flow path of the cooling water. The arrangement density of the plurality of first fins 361 in the first region 351 is greater than the arrangement density of the plurality of second fins 362 in the second region 352. With the above configuration, while suppressing an increase in water flow resistance in the cooler 30, the cooling performance of the first region 351 is enhanced. As a result, it is possible to efficiently cool the SiC MOSFET module 1 having a large heat generation amount at high temperatures. As a result, the total loss of the inverter 103 can be suppressed.

[0053] It is possible to freely combine each embodiment, or to appropriately modify or omit each embodiment. The above description is illustrative in all aspects. It is understood that innumerable variations not illustrated can be assumed.

Description of Reference Numerals

[0054] 1 SiC MOSFET module, 2 Si IGBT module, 4 battery, 5 capacitor, 6 motor, 7 control circuit for SiC MOSFET module, 8 control circuit for Si IGBT module, 9 inverter control circuit, 27 - 32 freewheel diodes, 30, 30A, 30B coolers, 32 housing, 33 water inlet pipe, 34 water outlet pipe, 35 top plate, 101, 102, 103 inverters, 351 first region, 352 second region, 361 first fins, 362 second fins.

Claims

1. a SiC MOSFET module including a plurality of SiC MOSFETs; a Si IGBT module including a plurality of Si IGBTs connected in parallel to the SiC MOSFET module; A SiC MOSFET module control circuit that controls the SiC MOSFET module 1; a control circuit for a Si IGBT module that controls the Si IGBT module; the SiC MOSFET module control circuit stops driving the SiC MOSFET module when an element temperature of the SiC MOSFET module is higher than a predetermined first threshold value; the control circuit for the Si IGBT module stops driving the Si IGBT module when an element temperature of the Si IGBT module is higher than a predetermined second threshold value; when an element temperature of the SiC MOSFET module is equal to or lower than the first threshold value and an element temperature of the Si IGBT module is equal to or lower than the second threshold value, a control circuit for the SiC MOSFET module drives the SiC MOSFET module and a control circuit for the Si IGBT module drives the Si IGBT module; the Si IGBT module control circuit reduces an output of the Si IGBT module when an element temperature of the SiC MOSFET module is higher than the first threshold value, compared to when the element temperature of the SiC MOSFET module is equal to or lower than the first threshold value; the SiC MOSFET module control circuit reduces an output of the SiC MOSFET module when an element temperature of the Si IGBT module is higher than the second threshold value, compared to when the element temperature of the Si IGBT module is equal to or lower than the second threshold value; Inverter.

2. Further comprising a cooler on which the SiC MOSFET module and the Si IGBT module are mounted, The cooling performance of the cooler at the mounting position of the SiC MOSFET module is higher than the cooling performance of the cooler at the mounting position of the Si IGBT module. The inverter according to claim 1 .

3. The cooler comprises: A housing and a water inlet pipe for taking in cooling water into the housing; a water outlet pipe for discharging the cooling water from inside the housing, the housing includes a first region in which the SiC MOSFET module is mounted and a second region in which the Si IGBT module is mounted, The first region is located upstream of the second region in a flow path of the cooling water from the inlet pipe to the outlet pipe. The inverter according to claim 2 .

4. The first region is thicker than the second region. The inverter according to claim 3 .

5. The cooler comprises: a plurality of first fins protruding from the first region into the cooling water flow path; a plurality of second fins protruding from the second region into the cooling water flow path, an arrangement density of the first fins in the first region is greater than an arrangement density of the second fins in the second region; The inverter according to claim 3 or 4.

6. An inverter according to any one of claims 1 to 5; a motor driven by the inverter. Electric vehicle.

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