Inverter and electric vehicle

Abstract

One objective of this disclosure is to reduce the overall losses of an inverter comprising a silicon switching element and a silicon carbide switching element connected in parallel. An inverter (101) comprises: a silicon carbide MOSFET module (1); a silicon carbide IGBT module (2) connected in parallel to the silicon carbide MOSFET module (1); a silicon carbide MOSFET module control circuit (7) that drives the silicon carbide MOSFET module (1); and a silicon carbide IGBT module control circuit (8) that drives the silicon carbide IGBT module (2). The silicon carbide MOSFET module control circuit (7) terminates the drive of the silicon carbide MOSFET module (1) when an element temperature of the silicon carbide MOSFET module (1) exceeds a first threshold. The Si-IGBT module control circuit (8) terminates the control of the Si-IGBT module (2) when an element temperature of the Si-IGBT module (2) is higher than a second threshold.

Description

Technical area

[0001] The present disclosure relates to an inverter and an electrically powered vehicle. State of the art

[0002] Patent Document 1 discloses a power conversion device such as an inverter used in an electric vehicle. The power conversion device includes silicon (Si) switching elements, silicon carbide (SiC) switching elements, each of which is connected in parallel with a corresponding one of the Si switching elements between a power supply and a load, and a controller that selectively drives a set of the switching elements. This controller drives only the SiC switching elements at a low current. Furthermore, this controller preferentially drives the Si switching elements at a high current, and drives the SiC switching elements instead of the Si switching elements when the temperature of the Si switching elements becomes high. State of the art documentPatent document

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2020-092505 SummaryProblem to be solved by the invention

[0004] SiC switching elements have lower losses than Si switching elements in a low current range, and Si switching elements have lower losses than SiC switching elements in a high current range. In the power conversion device in Patent Document 1, the switching elements with lower losses are selected and driven in accordance with a current. However, selectively driving only one set of switching elements makes it difficult to reduce overall losses.

[0005] The disclosure was devised to solve the problem and has an object of reducing the total loss of an inverter including a Si switching element and a SiC switching element connected in parallel. Means to solve the problem

[0006] An inverter comprises: a SiC MOSFET module having a plurality of SiC MOSFETs; a Si IGBT module connected in parallel to the SiC MOSFET module and having a plurality of Si IGBTs; a SiC MOSFET module control circuit that controls the SiC MOSFET module; and a Si IGBT module control circuit that controls the Si IGBT module. The SiC MOSFET module control circuit stops controlling the SiC MOSFET module when an element temperature of the SiC MOSFET module is higher than a predefined first threshold. The Si IGBT module control circuit stops controlling the Si IGBT module when an element temperature of the Si IGBT module is higher than a predefined second threshold.The SiC MOSFET module control circuit controls the SiC MOSFET module and the Si IGBT module control circuit controls the Si IGBT module when the element temperature of the SiC MOSFET module is less than or equal to the first threshold and the element temperature of the Si IGBT module is less than or equal to the second threshold. Effects of the invention

[0007] The overall losses of an inverter according to the present disclosure are reduced. The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying figures. Short description of the characters Fig. 1 is a circuit diagram illustrating an inverter according to Embodiment 1, which is connected to a battery, a capacitor, and a motor. Fig. Figure 2 illustrates the current-voltage characteristics of SiC MOSFETs and Si IGBTs. Fig. Figure 3 illustrates the general current-voltage characteristics of the SiC MOSFETs at 25°C and 150°C. Fig. Figure 4 illustrates the general current-voltage characteristics of the Si IGBTs at 25°C and 150°C. Fig. 5 illustrates that a SiC MOSFET module and a Si IGBT module are mounted on a cooling device according to Embodiment 1. Fig. 6 illustrates that the SiC MOSFET module and the Si IGBT module are mounted on a cooling device according to Embodiment 2. Fig. 7 illustrates that the SiC MOSFET module and the Si IGBT module are mounted on a cooling device according to Embodiment 3. Description of the Embodiments [A. Embodiment 1] [A-1. Structure]

[0008] Fig. 1 is a circuit diagram illustrating an inverter 101 according to Embodiment 1, which is connected to a battery 4, a capacitor 5, and a motor 6.

[0009] The motor 6 is a motor for an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0010] The inverter 101 comprises a SiC MOSFET module 1, a Si IGBT module 2, a SiC MOSFET module control circuit 7, a Si IGBT module control circuit 8, and an inverter control circuit 9.

[0011] The SiC MOSFET module 1 comprises a plurality of SiC metal oxide semiconductor field-effect transistors (MOSFETs). Fig. 1, the SiC MOSFET module 1 has six SiC MOSFETs 11 to 16. The SiC MOSFET 11 is a U-phase upper arm. The SiC MOSFET 12 is a U-phase lower arm. The SiC MOSFET 13 is a V-phase upper arm. The SiC MOSFET 14 is a V-phase lower arm. The SiC MOSFET 15 is a W-phase upper arm. The SiC MOSFET 16 is a W-phase lower arm.

[0012] The Si IGBT module 2 comprises a plurality of Si insulated gate bipolar transistors (IGBTs). Fig. 1, the Si-IGBT module 2 has six Si-IGBTs 21 to 26 and freewheeling diodes 27 to 32 connected in parallel with the respective Si-IGBTs 21 to 26. 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. The Si-IGBT 26 is a W-phase lower arm.

[0013] A P terminal, an N terminal, a U terminal, a V terminal, and a W terminal, which are main terminals of the SiC MOSFET module 1, are respectively connected in parallel to a P terminal, an N terminal, a U terminal, a V terminal, and a W terminal, which are main terminals of the Si-IGBT module 2. The U terminals, the V terminals, and the W terminals of the SiC MOSFET module 1 and the Si-IGBT module 2 are connected to the motor 6, and the P terminals and the N terminals thereof are connected to the battery 4 and the capacitor 5.

[0014] The SiC MOSFET module control circuit 7 is a control circuit for the SiC MOSFET module 1. Signal terminals such as gate terminals of the SiC MOSFETs 11 to 16 in the SiC MOSFET module 1 are connected to the SiC MOSFET module control circuit 7.

[0015] The Si-IGBT module control circuit 8 is a control circuit for the Si-IGBT module 2. Signal terminals such as gate terminals of the Si-IGBTs 21 to 26 in the Si-IGBT module 2 are connected to the Si-IGBT module control circuit 8.

[0016] The SiC MOSFET module control circuit 7 and the Si IGBT module control circuit 8 are connected to the inverter control circuit 9.

[0017] Fig. 1 illustrates the Si-IGBTs 21 to 26 and the freewheeling diodes 27 to 32 connected in parallel to the respective Si-IGBTs 21 to 26 as the structure of the Si-IGBT module 2. The freewheeling diodes 27 to 32 may include freewheeling diode elements separate from the IGBT elements included in the Si-IGBTs 21 to 26. Alternatively, the Si-IGBTs 21 to 26 and the freewheeling diodes 27 to 32 may include RC-IGBT elements that include freewheeling diodes.

[0018] Fig. 1 illustrates only the gate terminals as the signal terminals of the SiC MOSFETs 11 to 16 and the Si IGBTs 21 to 26. However, each of the SiC MOSFETs 11 to 16 and the Si IGBTs 21 to 26 may include a current sense terminal, a temperature sense terminal, and a collector sense terminal. Furthermore, each of the SiC MOSFETs 11 to 16 may include a source sense terminal. Furthermore, each of the Si IGBTs 21 to 26 may include an emitter sense terminal. [A-2. Operating procedures]

[0019] The SiC MOSFET module control circuit 7 switches the SiC MOSFET module 1 upon receiving a PWM signal from the inverter control circuit 9. As a result, the direct current input from the battery 4 or the capacitor 5 into the SiC MOSFET module 1 through the P terminal and the N terminal is output to the motor 6 through the U terminal, the V terminal, and the W terminal as a three-phase alternating current.

[0020] Similarly, the Si-IGBT module control circuit 8 switches the Si-IGBT module 2 upon receiving a PWM signal from the inverter control circuit 9. As a result, the direct current supplied from the battery 4 or the capacitor 5 to the Si-IGBT module 2 through the P terminal and the N terminal is output to the motor 6 through the U terminal, the V terminal, and the W terminal as a three-phase alternating current.

[0021] The SiC MOSFET module control circuit 7 monitors the element temperature of the SiC MOSFET module 1. If the element temperature is higher than a predefined first threshold, the SiC MOSFET module control circuit 7 blocks an input signal to the gate of the SiC MOSFET module 1. In this case, only the Si IGBT module 2 controls the motor 6. The SiC MOSFET module control circuit 7 simultaneously outputs a signal to the inverter control circuit 9 indicating that the element temperature of the SiC MOSFET module 1 is higher than the first threshold. Upon receiving the signal indicating that the element temperature of the SiC MOSFET module 1 is higher than the first threshold, the inverter control circuit 9 outputs a signal to the Si IGBT module control circuit 8 indicating that the output of the Si IGBT module 2 is to be suppressed. Subsequently, the Si-IGBT module control circuit 8 suppresses the output of the Si-IGBT module 2.This prevents an increase in the temperature of the single-driven Si-IGBT module 2.

[0022] Similarly, the Si-IGBT module control circuit 8 also monitors the element temperature of the Si-IGBT module 2. If the element temperature is higher than a predefined second threshold, the Si-IGBT module control circuit 8 blocks an input signal to the gate of the Si-IGBT module 2. Here, only the SiC MOSFET module 1 controls the motor 6. The Si-IGBT module control circuit 8 simultaneously outputs a signal to the inverter control circuit 9 indicating that the element temperature of the Si-IGBT module 2 is higher than the second threshold. Upon receiving the signal indicating that the element temperature of the Si-IGBT module 2 is higher than the second threshold, the inverter control circuit 9 outputs a signal to the SiC MOSFET module control circuit 7 indicating that the output of the SiC MOSFET module 1 is to be inhibited. Subsequently, the SiC MOSFET module control circuit 7 inhibits the output of the SiC MOSFET module 1.This prevents an increase in the temperature of the single-driven Si-IGBT module 2.

[0023] When the element temperature of the SiC MOSFET module 1 is less than or equal to the first threshold and the element temperature of the Si IGBT module 2 is less than or equal to the second threshold, both the SiC MOSFET module 1 and the Si IGBT module 2 are driven.

[0024] The SiC MOSFET module 1 and the Si IGBT module 2 differ in terms of cooling conditions, thermal conditions, and heat resistance. Therefore, the SiC MOSFET module 1 and the Si IGBT module 2 differ in terms of the element temperature threshold at which the input signal is blocked.

[0025] The heat generated in the SiC MOSFETs 11 to 16 and the Si IGBTs 21 to 26 is dissipated through the chip bonding pads on which these elements are mounted. The chip bonding pads tend to crack due to heating and cooling cycles caused by turning the elements on and off. Typically, the cracks impair heat dissipation, and the temperature of these elements rises without problems, contributing to the crack propagation. However, in the inverter 101 according to Embodiment 1, the SiC MOSFET module control circuit 7 and the Si IGBT module control circuit 8 monitor the element temperatures of the SiC MOSFETs 11 to 16 and the Si IGBTs 21 to 26 and stop driving these elements when the element temperatures reach the respective thresholds. Therefore, the progression of cracks in the chip bond joints can be delayed.

[0026] Fig. Figure 2 illustrates the current-voltage characteristics of SiC MOSFETs and Si IGBTs. By causing currents to flow through the SiC MOSFETs and Si IGBTs, losses are generated from the resistive components of these elements. However, the SiC MOSFETs and Si IGBTs exhibit different current characteristics, as shown in Fig. 2. Specifically, SiC MOSFETs have lower voltages, meaning lower resistances, in a low current range, and Si IGBTs have lower voltages, meaning lower resistances, in a high current range. When SiC MOSFETs are connected in parallel with Si IGBTs, a large amount of current flows through one side of low resistance.

[0027] Patent Document 1 proposes selectively driving the SiC MOSFET in a low current range and selectively driving the Si IGBTs in a high current range using these characteristics. However, driving both the SiC MOSFETs and the Si IGBTs in any of the low current range and the high current range reduces overall losses.

[0028] Fig. Figure 3 illustrates the general current-voltage characteristics of the SiC MOSFETs at 25°C and 150°C. Fig. Figure 4 illustrates the general current-voltage characteristics of the Si IGBTs at 25°C and 150°C.

[0029] As in Fig. 3 illustrates, the voltage of SiC MOSFETs increases more dramatically at high temperatures than at low temperatures. As shown in Fig. As illustrated in Figure 4, Si IGBTs exhibit lower voltages in a low current range at high temperatures, and conversely, Si IGBTs exhibit high voltages in a high current range at low temperatures. However, the voltage difference between high and low temperatures is not as large as that of SiC MOSFETs. Since each of these devices generates heat due to a resistive component when energized, a cooling device is required to cool the modules more efficiently.

[0030] Fig. 5 illustrates that the SiC MOSFET module 1 and the Si IGBT module 2 are mounted on a cooling device 30. In other words, the inverter 101 according to Embodiment 1 includes the cooling device 30.

[0031] The cooling device 30 includes a housing 32, an inlet water line 33, and an outlet water line 34. The housing 32 includes a top plate 35 on which the SiC MOSFET module 1 and the Si IGBT module 2 are mounted. A region of the top plate 35 in which the SiC MOSFET module 1 is mounted is referred to as a first region 351, and a region of the top plate 35 in which the Si IGBT module 2 is mounted is referred to as a second region 352. A coolant supplied from the inlet water line 33 to the housing 32 cools the SiC MOSFET module 1 and the Si IGBT module 2 while flowing through the housing 32, and exits from the outlet water line 34. Therefore, the housing 32 includes a coolant flow channel indicated by a dotted line arrow in Fig. 5 is marked.

[0032] As in Fig. As illustrated in Figure 5, the SiC MOSFET module 1 is mounted further upstream than the Si IGBT module 2 in the coolant flow channel. In other words, the first region 351 is located further upstream than the second region 352 in the coolant flow channel.

[0033] With such a structure, the coolant supplied to the casing 32 from the inlet water line 33 first cools the SiC MOSFET module 1 and then cools the Si IGBT module 2, and exits from the outlet water line 34. Since the coolant flows through the cooling device 30 while removing heat from each of the modules, the upstream SiC MOSFET module 1 is cooled with higher cooling efficiency than that of the downstream Si IGBT module 2.

[0034] As in the Fig. 3 and Fig. As illustrated in Figure 4, the heating value of SiC MOSFETs is higher than that of Si IGBTs at high temperatures. Therefore, arranging the SiC MOSFET module 1 at a position of the cooling device 30 with a higher cooling capacity than that of the Si IGBT module 2 can reduce the overall losses in the inverter 101. [A-3. Advantages]

[0035] The inverter 101 according to Embodiment 1 includes the SiC MOSFET module 1, which has the plurality of SiC MOSFETs 11 to 16, the Si IGBT module 2, which is connected in parallel to the SiC MOSFET module 1 and has the Si IGBTs 21 to 26, the SiC MOSFET module control circuit 7, which drives the SiC MOSFET module 1, and the Si IGBT module control circuit 8, which drives the Si IGBT module 2. The SiC MOSFET module control circuit 7 stops driving the SiC MOSFET module 1 when an element temperature of the SiC MOSFET module 1 is higher than a predefined first threshold. The Si-IGBT module control circuit 8 stops driving the Si-IGBT module 2 when an element temperature of the Si-IGBT module 2 is higher than a predefined second threshold.The SiC MOSFET module control circuit 7 controls the SiC MOSFET module 1 and the Si IGBT module control circuit 8 controls the Si IGBT module 2 when the element temperature of the SiC MOSFET module 1 is less than or equal to the first threshold and the element temperature of the Si IGBT module 2 is less than or equal to the second threshold.

[0036] In the aforementioned structure, both the SiC MOSFET module 1 and the Si IGBT module 2 drive the motor 6 when the element temperatures are not high. Consequently, the structure can reduce the overall losses in the inverter 101 more than if only one of the modules drives the motor 6.

[0037] In the case where the element temperature of the SiC MOSFET module 1 is higher than the first threshold, the Si-IGBT module control circuit 8 reduces the output of the Si-IGBT module 2 more than an output when the element temperature of the SiC MOSFET module 1 is less than or equal to the first threshold, and in the case where the element temperature of the Si-IGBT module 2 is higher than the second threshold, the SiC MOSFET module control circuit 7 reduces the output of the SiC MOSFET module 1 more than an output when the element temperature of the Si-IGBT module 2 is less than or equal to the second threshold. This can prevent the switching elements in the SiC MOSFET module 1 or the Si-IGBT module 2, which are operated alone, from being destroyed.

[0038] The inverter according to Embodiment 1 further includes the cooling device 30 on which the SiC MOSFET module 1 and the Si IGBT module 2 are mounted, wherein a cooling performance of the cooling device 30 at a position where the SiC MOSFET module 1 is mounted is higher than a cooling performance of the cooling device 30 at a position where the Si IGBT module 2 is mounted. This allows the SiC MOSFET module 1, which has a higher heating value, to be cooled more preferentially at a high temperature than the Si IGBT module 2, which can suppress the overall loss in the inverter 101.

[0039] The cooling device 30 includes: the housing 32, the inlet water line 33 that supplies a coolant into the housing 32; and the outlet water line 34 that discharges the coolant from the housing 32. The housing 32 includes the first region 351 in which the SiC MOSFET module 1 is mounted, and the second region 352 in which the Si IGBT module 2 is mounted. The first region 351 is located further upstream than the second region 352 in a flow channel of the coolant from the inlet water line 33 to the outlet water line 34. Therefore, the coolant supplied from the inlet water line 33 to the cooling device 3 removes heat from the SiC MOSFET module 1 earlier than from the Si IGBT module 2. This allows the SiC MOSFETs with a higher heating value to be cooled more preferentially at a high temperature than the Si IGBTs, which can suppress the overall losses in the inverter 101. [B. Embodiment 2][B-1. Structure]

[0040] The circuit structure of an inverter 102 according to Embodiment 2 is that shown in Fig. 1, and is identical to that of the inverter 101 according to Embodiment 1. The inverter 102 has a cooling device 30A instead of the cooling device 30 in the inverter 101 according to Embodiment 1.

[0041] Fig. 6 illustrates that the SiC MOSFET module 1 and the Si IGBT module 2 are mounted on the top plate 35 of the cooling device 30A. The arrangement of the SiC MOSFET module 1 further upstream than the Si IGBT module 2 in the coolant flow channel is identical to that in Embodiment 1.

[0042] The first region 351 is thicker than the second region 352 in the upper plate 35 of the cooling device 30A. In other words, the first region 351 has a larger heat capacity and a higher cooling performance than those of the second region 352. The structure of the cooling device 30A except for the thickness of the upper plate 35 is identical to that of the cooling device 30 according to Embodiment 1.

[0043] The load of an electric vehicle including the inverter 102 temporarily increases during sudden acceleration such as overtaking. A large current flows through the SiC MOSFET module 1 with a lower resistance value, which immediately increases the heating value. However, in the inverter 102, the heat in the SiC MOSFET module 1 can be dissipated not only to the coolant of the cooling device 30A but also to the first region 351 of the upper plate 35, which has a high heat capacity. Therefore, the rise in the element temperature in the SiC MOSFET module 1 can be suppressed. [B-2. Advantages]

[0044] The housing 32 of the cooling device 30A in the inverter 102 according to Embodiment 2 includes the first region 351 in which the SiC MOSFET module 1 is mounted, and the second region 352 in which the Si-IGBT module 2 is mounted. The first region 351 is thicker than the second region 352. This increases the cooling performance of the SiC MOSFET module 1 with a higher heating value at a high temperature. Thus, the overall losses in the inverter 102 can be suppressed. [C. Embodiment 3][C-1. Structure]

[0045] The circuit structure of an inverter 103 according to Embodiment 3 is that shown in Fig. 1, and is identical to that of the inverter 101 according to Embodiment 1. The inverter 103 has a cooling device 30B instead of the cooling device 30 in the inverter 101 according to Embodiment 1.

[0046] Fig. 7 illustrates that the SiC MOSFET module 1 and the Si IGBT module 2 are mounted on the top plate 35 of the cooling device 30B. Fig. 7 illustrates, by means of dotted lines, an outer frame part excluding the top plate 35 of the cooling device 30B to visualize internal fins of the cooling device 30B. The arrangement of the SiC MOSFET module 1 further upstream than the Si IGBT module 2 in the coolant flow channel is identical to that in Embodiment 1.

[0047] The cooling device 30B differs from the cooling device 30 according to Embodiment 1 in that a plurality of first ribs 361, which protrude from the first region 351 of the upper plate 35 into the cooling device 30B, and a plurality of second ribs 362, which protrude from the second region 352 of the upper plate 35 into the cooling device 30B, are included. The first ribs 361 and the second ribs 362, which are pin ribs in Fig.7 can be ribs of a different shape.

[0048] The cooling capacity and hydraulic resistance of the fins of a cooling device vary depending on the fin shape. Fins that are densely arranged increase the contact area between the fins and the coolant, which increases heat exchange efficiency. Conversely, fins that are densely arranged increase the hydraulic resistance and reduce the coolant's velocity.

[0049] In this regard, the plurality of first fins 361 are arranged in series with the plurality of second fins 362 in the flow channel of the coolant from the inlet water pipe 33 to the outlet water pipe 34 in the cooling device 30B according to Embodiment 3. A density of the plurality of first fins 361 arranged in the first region 351 is higher than that of the plurality of second fins 362 arranged in the second region 352. In other words, the plurality of first fins 361 are densely arranged, and the plurality of second fins 362 are sparsely arranged.

[0050] This structure can suppress an increase in hydraulic resistance more than a structure in which all fins are densely arranged, and can efficiently cool the SiC MOSFET module 1. [C-2. Advantages]

[0051] The casing 32 of the cooling device 30B in the inverter 103 according to Embodiment 3 includes the first region 351 in which the SiC MOSFET module 1 is mounted, and the second region 352 in which the Si-IGBT module 2 is mounted. The cooling device 30B includes: the plurality of first fins 361 protruding from the first region 351 into the coolant flow channel; and the plurality of second fins 362 protruding from the second region 352 into the coolant flow channel. A density of the plurality of first fins 361 arranged in the first region 351 is higher than a density of the plurality of second fins 362 arranged in the second region 352. The above structure suppresses an increase in hydraulic resistance in the cooling device 30 and increases the cooling performance in the first region 351.As a result, the SiC MOSFET module 1 with a high heating value can be efficiently cooled at a high temperature. This can reduce the overall losses in the inverter 103.

[0052] Embodiments can be freely combined, modified, or omitted as appropriate. The above description is illustrative in all aspects. Therefore, numerous modifications and variations not yet illustrated may be conceived. List of reference symbols

[0053] 1 SiC MOSFET module, 2 Si IGBT module, 4 battery, 5 capacitor, 6 motor, 7 SiC MOSFET module control circuit, 8 Si IGBT module control circuit, 9 inverter control circuit, 27 to 32 freewheeling diode, 30, 30A, 30B cooling device, 32 housing, 33 inlet water pipe, 34 outlet water pipe, 35 upper plate, 101, 102, 103 inverter, 351 first region, 352 second region, 361 first fin, 362 second fin. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2020-092505

[0003]

Claims

[1] Inverter comprising: • a SiC MOSFET module comprising a plurality of SiC MOSFETs; • a Si-IGBT module connected in parallel to the SiC-MOSFET module and having a plurality of Si-IGBTs; • a SiC MOSFET module control circuit which controls the SiC MOSFET module 1; and • a Si-IGBT module control circuit which controls the Si-IGBT module, wherein • 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 predefined first threshold, • the Si-IGBT module control circuit stops driving the Si-IGBT module when an element temperature of the Si-IGBT module is higher than a predefined second threshold, and • the SiC MOSFET module control circuit controls the SiC MOSFET module and the Si IGBT module control circuit controls the Si IGBT module when the element temperature of the SiC MOSFET module is less than or equal to the first threshold and the element temperature of the Si IGBT module is less than or equal to the second threshold. [2] Inverter according to claim 1, wherein • in the case where the element temperature of the SiC MOSFET module is higher than the first threshold, the Si-IGBT module control circuit reduces an output of the Si-IGBT module more than the output when the element temperature of the SiC MOSFET module is less than or equal to the first threshold, and • in the case where the element temperature of the Si-IGBT module is higher than the second threshold, the SiC-MOSFET module control circuit reduces an output of the SiC-MOSFET module more than the output when the element temperature of the Si-IGBT module is less than or equal to the second threshold. [3] Inverter according to claim 1 or 2 further comprising • a cooling device on which the SiC MOSFET module and the Si IGBT module are mounted, wherein • a cooling performance of the cooling device at a position where the SiC MOSFET module is mounted is higher than a cooling performance of the cooling device at a position where the Si IGBT module is mounted. [4] Inverter according to claim 3, wherein • the cooling device has: ◯ a housing; ◯ an inlet water line providing a coolant in the housing; and ◯ an outlet water line which discharges the coolant from the housing, • the housing has a first region in which the SiC MOSFET module is mounted and a second region in which the Si IGBT module is mounted, and • the first region is located further upstream than the second region in a flow channel of the coolant from the inlet water line to the outlet water line. [5] The inverter of claim 4, wherein the first region is thicker than the second region. [6] Inverter according to claim 4 or 5, wherein • the cooling device has: ◯ a plurality of first fins projecting from the first region into the coolant flow channel; and ◯ a plurality of second fins projecting from the second region into the flow channel of the coolant, and • a density of the plurality of first ribs arranged in the first region is higher than a density of the plurality of second ribs arranged in the second region. [7] Electrically powered vehicle comprising: • the inverter according to one of claims 1 to 6; and • a motor controlled by the inverter.

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