Drive unit

Abstract

This prevents the temperature of the positive electrode switch from rising excessively during temperature control. [Solution] When the electric vehicle performs temperature-raising control to raise the temperature of the motor and / or the first and second inverters, the positive-side switch is turned ON, and the first and second inverters are controlled by setting duty cycle commands based on feedforward and feedback terms so that the phase current of each phase of the motor circulates through one of the first and second inverters, the positive-side line and the negative-side line, and the other of the first and second inverters. Furthermore, when the temperature of the positive-side switch is higher than the first temperature during temperature-raising control, the feedforward term is reduced compared to when the temperature of the positive-side switch is below the first temperature.

Description

Technical Field

[0001] The present disclosure relates to a drive device.

Background Art

[0002] Conventionally, there has been proposed a control device for a motor including a phase change mechanism including a first rotor and a second rotor each provided with magnet pieces, and first and second working chambers that relatively rotate the first and second rotors when a working fluid is supplied to change the phase indicating the relative rotation angle between the two (see, for example, Patent Document 1). When the temperature of the working fluid is less than a predetermined value, this control device energizes the stator coil of the motor to warm the working fluid.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Incidentally, a drive device has also been devised that includes a power storage device, a motor having a three-phase open winding, a first inverter connected to the positive and negative lines to which the power storage device is connected and also connected to one end of the three-phase open winding, a second inverter connected to the positive and negative lines and also connected to the other end of the three-phase open winding, and a positive switch provided between the first and second inverters on the positive line. In this drive device, when performing temperature-raising control to raise the temperature of the motor and / or the first and second inverters, the positive switch is turned ON, and the first and second inverters are controlled so that the phase current of each phase of the motor circulates through one of the first and second inverters, between the first and second inverters on the positive and negative lines, and through the other inverter. During this temperature-raising control, it is required to suppress the temperature of the positive switch from rising excessively.

[0005] The primary purpose of the drive device of this disclosure is to suppress an excessive rise in the temperature of the positive electrode switch during temperature rise control. [Means for solving the problem]

[0006] The drive device of this disclosure employs the following means to achieve the main objective described above.

[0007] [1] The drive device of the present disclosure is Energy storage device, A motor having a 3-phase open winding, The first inverter is connected to the positive and negative lines to which the energy storage device is connected, and is also connected to one end of the three-phase open winding. A second inverter is connected to the positive electrode line and the negative electrode line, and is also connected to the other end of the three-phase open winding. A positive electrode side switch provided between the first and second inverters in the positive electrode side line, When performing temperature-raising control to raise the temperature of the motor and / or the first and second inverters, a control device controls the first and second inverters by setting the positive-side switch to the ON state and setting first and second duty cycle commands so that the phase current of each phase of the motor circulates through one of the first and second inverters, the positive-side line and the negative-side line between the first and second inverters, and the other of the first and second inverters. A drive device equipped with, The control device, during the temperature rise control, reduces the first and second duty cycle commands when the temperature of the positive electrode switch is higher than the first temperature, compared to when the temperature of the positive electrode switch is at or below the first temperature. This is the gist of it.

[0008] In the drive device of this disclosure, when the control device performs temperature rise control to raise the temperature of the motor and / or the first and second inverters, it sets the positive side switch to the ON state and controls the first and second inverters by setting first and second duty commands so that the phase current of each phase of the motor circulates through one of the first and second inverters, the positive side line and the first and second inverters of the negative side line, and the other of the first and second inverters. During this temperature rise control, if the temperature of the positive side switch is higher than the first temperature, the first and second duty commands are reduced compared to when the temperature of the positive side switch is at or below the first temperature. As a result, when the temperature of the positive side switch is higher than the first temperature during temperature rise control, the absolute value of the current between the first and second inverters of the positive side line is reduced, thereby suppressing an excessive rise in the temperature of the positive side switch.

[0009] [2] In the drive device of the present disclosure (the drive device described in [1] above), the control device may, when performing the temperature rise control, set one of the first and second duty commands by adding a feedback term to the feedforward term and set the other of the first and second duty commands by subtracting the feedback term from the feedforward term, and when the temperature of the positive electrode switch is higher than the first temperature, the feedforward term may be smaller than when the temperature of the positive electrode switch is at or below the first temperature.

[0010] In the drive device of the present disclosure (the drive device described in [1] or [2] above), the control device further comprises a negative electrode side switch provided between the first and second inverters in the negative electrode side line, and when the temperature of the negative electrode side switch is higher than the second temperature during temperature rise control, the control device may increase the first and second duty cycle commands compared to when the temperature of the negative electrode side switch is at or below the second temperature. This makes it possible to reduce the absolute value of the current between the first and second inverters in the negative electrode side line when the temperature of the negative electrode side switch is higher than the second temperature during temperature rise control, thereby suppressing an excessive rise in the temperature of the negative electrode side switch.

[0011] [4] In this case (the drive device described in [3] above), the control device may, when performing the temperature rise control, set one of the first and second duty commands by adding a feedback term to the feedforward term and set the other of the first and second duty commands by subtracting the feedback term from the feedforward term, and when the temperature of the positive electrode switch is higher than the first temperature, the feedforward term may be made smaller than when the temperature of the positive electrode switch is at or below the first temperature, and when the temperature of the negative electrode switch is higher than the second temperature, the feedforward term may be made larger than when the temperature of the negative electrode switch is at or below the second temperature.

[0012] [5] In this case (the drive device described in [4] above), the control device may calculate the feedforward term by adding to the base value of the feedforward term a first correction value which decreases as the temperature of the positive electrode switch increases, and a second correction value which increases as the temperature of the negative electrode switch increases. [Brief explanation of the drawing]

[0013] [Figure 1] This is a schematic diagram of the electric vehicle according to the embodiments of the present disclosure. [Figure 2] This is an explanatory diagram showing an example of the functional blocks for the U-phase of the first and second inverters in temperature rise control. [Figure 3] This is an explanatory diagram showing an example of the first correction amount map. [Figure 4] This is an explanatory diagram showing an example of a second correction amount map. [Modes for carrying out the invention]

[0014] Embodiments for implementing this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of an electric vehicle 10 according to an embodiment of this disclosure. As shown in the figure, the electric vehicle 10 of the embodiment includes a battery 12 as an energy storage device, a motor 20, first and second inverters 22 and 24, a capacitor 30, a positive-side switch 33 and a negative-side switch 34, a cooling device 40, and an electronic control unit (hereinafter referred to as "ECU") 50 as a control device.

[0015] The battery 12 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery and is connected to the power line 28 (positive electrode line 28p and negative electrode line 28n). The motor 20 is configured as a three-phase AC motor and comprises a rotor with permanent magnets embedded in the rotor core and a stator with three-phase (U-phase, V-phase, W-phase) coils (three-phase open windings) wound around the stator core. The rotor is connected to a drive shaft which is linked to the drive wheels via a differential gear.

[0016] The first and second inverters 22 each include six transistors T11 to T16 and T21 to T26 as a plurality of switching elements, and six diodes D11 to D16 and D21 to D26 each connected in parallel to the six transistors T11 to T16 and T21 to T26. As the transistors T11 to T16 and T21 to T26, for example, MOSFETs, IGBTs, etc. are used. The transistors T11 to T16 and T21 to T26 are arranged in pairs of two so as to be the source side and the sink side with respect to the positive electrode side line 28p and the negative electrode side line 28n. Each of the connection points of the two transistors that form a pair of transistors T11 to T16 is connected to each of one ends of the three-phase coils of the motor 20. Each of the connection points of the two transistors that form a pair of transistors T21 to T26 is connected to each of the other ends of the three-phase coils of the motor 20. Hereinafter, the transistors T11 to T13 and T21 to T23 may be referred to as "upper arms", and the transistors T14 to T16 and T24 to T25 may be referred to as "lower arms".

[0017] The capacitor 30 is connected near the first inverter 22 in the power line 28. In the embodiment, in the power line 28, from the left side of FIG. 1, the battery 12, the capacitor 30, the first inverter 22, and the second inverter 24 are connected in this order. The positive electrode side switch 33 and the negative electrode side switch 34 are provided between the first and second inverters 22 and 24 in the positive electrode side line 28p and the negative electrode side line 28n, respectively. Note that the positive electrode side switch 33 and the negative electrode side switch 34 may be semiconductor type switches or may be relays or the like.

[0018] The cooling device 40 includes a circulation flow path 42, a radiator 44, and an electric pump 46. The circulation flow path 42 is configured as a flow path for circulating cooling water in this order through the second inverter 24, the motor 20, the first inverter 22, the battery 12, and the radiator 44. The electric pump 46 pumps (circulates) the cooling water in the circulation flow path 42. Note that the circulation flow path 42 may be configured to circulate the cooling water in any order through the motor 20 and the first and second inverters 22 and 24.

[0019] The ECU 50 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, communication ports, various drive circuits, and various logic ICs. Signals from various sensors are input to the ECU 50. For example, the voltage Vb of the battery 12 from the voltage sensor 12v, the current Ib of the battery 12 from the current sensor 12i, and the temperature αb of the battery 12 from the temperature sensor 12t are input to the ECU 50. The rotational position θm of the rotor of the motor 20 from the rotational position sensor 20a, the phase currents Iu, Iv, Iw of each phase of the motor 20 from the current sensors 20u, 20v, 20w, and the temperature αm of the motor 20 from the temperature sensor 20t are also input to the ECU 50. The temperature αi1 of the first inverter 22 from the temperature sensor 22t, the temperature αi2 of the second inverter 24 from the temperature sensor 24t, the voltage VH of the capacitor 30 from the voltage sensor 30v, the temperature αsp of the positive-side switch 33 from the temperature sensor 33t, the temperature αsn of the negative-side switch 34 from the temperature sensor 34t, and the temperature αw of the cooling water in the circulation passage 42 from the temperature sensor 48 are also input to the ECU 50. The on / off signal from the power switch, the shift position SP which is the operating position of the shift lever from the shift position sensor, the accelerator opening Acc which is the depression amount of the accelerator pedal from the accelerator pedal position sensor, the brake pedal position BP which is the depression amount of the brake pedal from the brake pedal position sensor, the vehicle speed V from the vehicle speed sensor, and the outside air temperature αo from the outside air temperature sensor 52 are also input to the ECU 50.

[0020] Various control signals are output from the ECU 50. For example, control signals to the transistors T11 to T16 of the first inverter 22, the transistors T21 to T26 of the second inverter 24, the positive-side switch 33, and the negative-side switch 34 are output from the ECU 50. The ECU 50 calculates the state of charge SOC of the battery 12 based on the integrated value of the current Ib of the battery 12, or calculates the electrical angle θe and the rotational speed Nm of the motor 20 based on the rotational position θm of the rotor of the motor 20.

[0021] In the electric vehicle 10 of this embodiment, the ECU 50 sets the required torque Td* required for driving based on the accelerator opening Acc and the vehicle speed V, sets the torque command Tm* for the motor 20 to drive with the set required torque Td*, and performs switching control of the transistors T11~T16 and T21~T26 of the first and second inverters 22 and 24 based on the set torque command Tm*.

[0022] Next, the operation of the electric vehicle 10 of the embodiment will be described, in particular, when at least one temperature-raising request is made for the battery 12, motor 20, first and second inverters 22 and 24 while the vehicle is stopped, and temperature-raising control is performed. Such temperature-raising requests are made, for example, when the ambient temperature αo from the ambient temperature sensor 52 is below the threshold αoref, when the temperature αb of the battery 12 from the temperature sensor 12t is below the threshold Tbref, when the temperature αm of the motor 20 from the temperature sensor 20t is below the threshold αmref, when the temperature αi1 of the first inverter 22 from the temperature sensor 22t is below the threshold αi1ref, when the temperature αi2 of the second inverter 24 from the temperature sensor 24t is below the threshold αi2ref, and when the temperature αw of the cooling water in the circulation channel 42 from the temperature sensor 48 is below the threshold αwref. In addition, during temperature control, the positive-side switch 33 and the negative-side switch 34 are turned ON, and the first and second inverters 22 and 24 are controlled to circulate current in the order of first inverter 22, motor 20, second inverter 24, power line 28 (positive-side line 28p and negative-side line 28n), between the first and second inverters 22 and 24 (including the positive-side switch 33 and the negative-side switch 34), and then the first inverter 22, or in the reverse order. This raises the temperature of the motor 20 and the first and second inverters 22 and 24, or uses the heat from the motor 20 and the first and second inverters 22 and 24 to raise the temperature of the battery 12 via the cooling water in the circulation channel 42.

[0023] Figure 2 is an explanatory diagram showing an example of a functional block for controlling the U-phase (transistors T11, T14, T21, T24) of the first and second inverters 22 and 24 in temperature rise control. The functional block is constructed through the cooperation of hardware such as the CPU and multiple programs installed in ROM or flash memory. The control of the V-phase (transistors T12, T15, T22, T25) and W-phase (transistors T13, T16, T23, T26) of the first and second inverters 22 and 24 in temperature rise control is similar.

[0024] The ECU 50 comprises, as a functional block, a multiplication unit 61, a subtraction unit 62, a proportional term calculation unit 63, an integral term calculation unit 64, an addition unit 65, a first correction amount setting unit 66, a second correction amount setting unit 67, an addition unit 68, an addition unit 69, and a subtraction unit 70. The multiplication unit 61 calculates the U-phase phase current command Iu* by multiplying the zero-sequence current command I0* by 1 / 3. The phase current command Iu* and the phase current Iu are defined with the direction from the first inverter 22 to the second inverter 24 (rightward in Figure 1) as the positive value. The zero-sequence current command I0* is a command value of the zero-sequence current corresponding to the sum of the phase currents of the U-phase, V-phase, and W-phase, and may be determined based on the temperature of the battery 12, motor 20, or the first and second inverters 22 and 24 for which a temperature rise request has been made, or a predetermined constant value may be used.

[0025] The subtraction unit 62 calculates the difference ΔIu by subtracting the phase current Iu from the U-phase phase current command Iu*. The proportional term calculation unit 63 and the integral term calculation unit 64 calculate the proportional term Dufbp and the integral term Dufbi by multiplying the difference ΔIu by the gains Kp and Ki of the proportional and integral terms, respectively. The addition unit 65 calculates the feedback term Dufb, which is used to set the first and second duty cycle commands Du1* and Du2*, as the sum of the proportional term Dufbp and the integral term Dufbi. The first and second duty cycle commands Du1* and Du2* are the ratio of the on-time of transistors T11 and T21 (upper arm) and transistors T14 and T24 (lower arm) of the first and second inverters 22 and 24 to the sum of their on-times, respectively.

[0026] The first and second correction amount setting units 66 and 67 set the first and second correction amounts ΔDuff1 and ΔDuff2. Details of this will be described later. The addition unit 68 adds the first and second correction amounts ΔDuff1 and ΔDuff2 to the base value Duff0 to calculate the feedforward term Duff used to set the first and second duty commands Du1 and Du2*. For example, 0.5 is used for the base value Duff0. The addition unit 69 adds the feedback term Dufb to the feedforward term Duff to calculate the first duty command Du1*. The subtraction unit 70 subtracts the feedback term Dufb from the feedforward term Duff to calculate the second duty command Du2*. After calculating the first and second duty cycle commands Du1* and Du2*, the duty cycle control of transistors T11, T14, T21, and T24 is performed based on the calculated first and second duty cycle commands Du1* and Du2*.

[0027] Here, the details of the setting process for the first and second correction amounts ΔDuff1 and ΔDuff2 by the first and second correction amount setting units 66 and 67 will be explained. The first correction amount setting unit 66 sets the first correction amount ΔDuff1 based on the temperature αsp of the positive electrode side switch 33 from the temperature sensor 33t and the first correction amount map. The first correction amount map is predetermined by experiments and analyses based on the specifications of the positive electrode side switch 33, as a relationship between the temperature αsp of the positive electrode side switch 33 and the first correction amount ΔDuff1. Figure 3 is an explanatory diagram showing an example of the first correction amount map. As shown in the figure, in the region where the temperature αsp of the positive electrode side switch is less than or equal to the threshold αsp1, the value 0 is set as the first correction amount ΔDuff1. Also, in the region where the temperature αsp of the positive electrode side switch 33 is higher than the threshold αsp1 and less than the threshold αsp2, the value that gradually decreases from 0 towards a negative value β1 is set as the first correction amount ΔDuff1. Furthermore, in the region where the temperature αsp of the positive electrode switch 33 is greater than or equal to the threshold αsp2, the value β1 is set to the first correction amount ΔDuff1. Therefore, the feedforward term Duff, and consequently the first and second duty commands Du1* and Du2*, tend to become smaller as the temperature αsp of the positive electrode switch 33 increases in the region where it exceeds the threshold αsp1.

[0028] The second correction amount setting unit 67 sets the second correction amount ΔDuff2 based on the temperature αsn of the negative electrode switch 34 from the temperature sensor 34t and the second correction amount map. The second correction amount map is predetermined by experiments and analyses based on the specifications of the negative electrode switch 34, as a relationship between the temperature αsn of the negative electrode switch 34 and the second correction amount ΔDuff2. Figure 4 is an explanatory diagram showing an example of the second correction amount map. As shown in the figure, in the region where the temperature αsn of the negative electrode switch is less than or equal to the threshold αsn1, the value 0 is set as the second correction amount ΔDuff2. Also, in the region where the temperature αsp of the negative electrode switch 34 is higher than the threshold αsn1 and less than the threshold αsn2, the value that gradually increases from 0 towards a positive value β2 is set as the second correction amount ΔDuff2. Furthermore, in the region where the temperature αsn of the negative electrode switch 34 is greater than or equal to the threshold αsn2, the value β2 is set as the second correction amount ΔDuff2. Therefore, the feedforward term Duff, and consequently the first and second duty commands Du1* and Du2*, tend to increase as the temperature αsn of the negative electrode switch 34 increases in the region where it exceeds the threshold αsn1.

[0029] Basically, the smaller the first and second duty commands Du1* and Du2*, the smaller the absolute value of the current I0p between the first and second inverters 22 and 24 (including the positive side switch 33) on the positive side line 28p becomes, and the larger the absolute value of the current I0n between the first and second inverters 22 and 24 (including the negative side switch 34) on the negative side line 28n becomes. Based on this, the higher the temperature αsp of the positive side switch 33 is in the region exceeding the threshold αsp1, the smaller the first and second duty commands Du1* and Du2* become, thereby reducing the absolute value of the current I0p between the first and second inverters 22 and 24 on the positive side line 28p and suppressing an excessive rise in the temperature αsp of the positive side switch 33. Furthermore, by increasing the first and second duty commands Du1* and Du2* as the temperature αsn of the negative electrode switch 34 rises above the threshold αsn1, the absolute value of the current I0n between the first and second inverters 22 and 24 of the negative electrode line 28n can be reduced, thereby suppressing an excessive rise in the temperature αsn of the negative electrode switch 34.

[0030] In the drive unit mounted on the electric vehicle 10 of the embodiment described above, when controlling the temperature rise, if the temperature αsp of the positive electrode switch 33 is higher than the threshold αsp1, the first correction amount ΔDuff1 is made smaller compared to when the temperature αsp of the positive electrode switch 33 is below the threshold αsp1, thereby reducing the feedforward term Duff and, consequently, the first and second duty commands Du1* and Du2*. This reduces the absolute value of the current I0p between the first and second inverters 22 and 24 of the positive electrode line 28p, and suppresses an excessive rise in the temperature αsp of the positive electrode switch 33.

[0031] Furthermore, during temperature rise control, if the temperature αsn of the negative electrode switch 34 is higher than the threshold αsn1, the second correction amount ΔDuff2 is increased compared to when the temperature αsn of the negative electrode switch 34 is below the threshold αsn1, thereby increasing the feedforward term Duff and consequently the first and second duty commands Du1* and Du2*. This reduces the absolute value of the current I0n between the first and second inverters 22 and 24 of the negative electrode line 28n, thereby suppressing an excessive rise in the temperature αsn of the negative electrode switch 34.

[0032] In the embodiment described above, the first duty cycle command Du1* is calculated by adding the feedback term Duufb to the feedforward term Duff, and the second duty cycle command Du2* is calculated by subtracting the feedback term Duufb from the feedforward term Duff. However, the first duty cycle command Du1* may be calculated by subtracting the feedback term Duufb from the feedforward term Duff, and the second duty cycle command Du2* may be calculated by adding the feedback term Duufb to the feedforward term Duff.

[0033] In the embodiment described above, the electric vehicle 10 is provided with a positive-side switch 33 and a negative-side switch 34, but is not limited to this. For example, it may be provided with only a positive-side switch 33. If only a positive-side switch 33 is provided, the second correction amount ΔDuff2 is not required when setting the feedforward term Duff during temperature rise control.

[0034] In the embodiment described above, the drive system is configured to be mounted on an electric vehicle 10 that includes a motor 20 and first and second inverters 22 and 24, but it is not limited to this. For example, it may be configured to be mounted on a hybrid vehicle that has an engine in addition to the same hardware configuration as the electric vehicle 10, or it may be configured to be mounted on a fuel cell vehicle that has a fuel cell in addition to the same hardware configuration as the electric vehicle 10.

[0035] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be explained. In the embodiment, the battery 12 corresponds to the "energy storage device", the motor 20 corresponds to the "motor", the first inverter 22 corresponds to the "first inverter", the second inverter 24 corresponds to the "second inverter", the positive side switch 33 corresponds to the "positive side switch", and the ECU 50 corresponds to the "control device". Also, the negative side switch 34 corresponds to the "negative side switch".

[0036] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0037] Although the embodiments for implementing this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and it is of course possible to implement it in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0038] This disclosure can be used in industries such as the manufacturing of drive systems. [Explanation of Symbols]

[0039] 10 Electric vehicle, 12 Battery, 12i, 20u, 20v, 20w Current sensor, 12t, 20t, 22t, 24t, 33t, 34t, 48 Temperature sensor, 12v, 30v Voltage sensor, 20 Motor, 20a Rotation position sensor, 22 First inverter, 24 Second inverter, 26 Battery, 28 Power line, 28n Negative side line, 28p Positive side line, 30 Capacitor, 33 Positive side switch, 34 Negative side switch, 40 Cooling device, 42 Circulation path, 44 Radiator, 46 Electric pump, 50 ECU, 52 Ambient temperature sensor, 61 Multiplication unit, 62 Subtraction unit, 63 Proportional term calculation unit, 64 Integral term calculation unit, 65 Addition unit, 66 First correction amount setting unit, 67 Second correction amount setting unit, 68 Addition unit, 69 Addition section, subtraction section (70), D11-D16 diodes, T11-T16 transistors.

Claims

1. Energy storage device, A motor having a three-phase open winding, The first inverter is connected to the positive and negative lines to which the energy storage device is connected, and is also connected to one end of the three-phase open winding. A second inverter is connected to the positive electrode line and the negative electrode line, and is also connected to the other end of the three-phase open winding. A positive electrode side switch provided between the first and second inverters in the positive electrode side line, When performing temperature-raising control to raise the temperature of the motor and / or the first and second inverters, the control device sets the positive-side switch to the ON state and controls the first and second inverters by setting first and second duty cycle commands so that the phase current of each phase of the motor circulates through one of the first and second inverters, the positive-side line and the negative-side line between the first and second inverters, and the other of the first and second inverters. A drive device equipped with, The control device, during the temperature rise control, reduces the first and second duty cycle commands when the temperature of the positive electrode switch is higher than the first temperature, compared to when the temperature of the positive electrode switch is below the first temperature. Drive unit.

2. A drive device according to claim 1, The control device, when performing the temperature rise control, Adding a feedback term to the feedforward term sets one of the first and second duty commands, and subtracting the feedback term from the feedforward term sets the other of the first and second duty commands. When the temperature of the positive electrode switch is higher than the first temperature, the feedforward term is reduced compared to when the temperature of the positive electrode switch is lower than or equal to the first temperature. Drive unit.

3. A drive device according to claim 1, The negative electrode side line further includes a negative electrode side switch provided between the first and second inverters, The control device, during the temperature rise control, increases the first and second duty cycle commands when the temperature of the negative electrode switch is higher than the second temperature, compared to when the temperature of the negative electrode switch is below the second temperature. Drive unit.

4. A drive device according to claim 3, The control device, when performing the temperature rise control, Adding a feedback term to the feedforward term sets one of the first and second duty commands, and subtracting the feedback term from the feedforward term sets the other of the first and second duty commands. When the temperature of the positive electrode switch is higher than the first temperature, the feedforward term is reduced compared to when the temperature of the positive electrode switch is lower than or equal to the first temperature. When the temperature of the negative electrode switch is higher than the second temperature, the feedforward term is increased compared to when the temperature of the negative electrode switch is lower than or equal to the second temperature. Drive unit.

5. A drive device according to claim 4, The control device calculates the feedforward term by adding to the base value of the feedforward term a first correction value that decreases as the temperature of the positive electrode switch increases, and a second correction value that increases as the temperature of the negative electrode switch increases. Drive unit.

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