Power conversion device and drive device

Abstract

To reliably melt down a fuse at a short-circuit fault location in a switching element when the fault occurs.SOLUTION: A power conversion device comprises: a power conversion circuit 30 in which at least three phases of upper and lower arm circuits in which power semiconductor elements 32 being switching elements are connected in series, are connected in parallel; and a plurality of fuses 60 each connected in series to power semiconductor elements 32 of each phase of the power conversion circuit 30 to melt down at a predetermined rated current or more. The power conversion device determines a short-circuit fault location of the power semiconductor elements 32, and controls driving the other power semiconductor elements 32 different from the power semiconductor element 32 so that a current flowing in the power semiconductor element 32 determined to be the short-circuit fault location becomes the rated current or more of the fuse 60.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a power conversion device and a drive device.

Background Art

[0002] When a switching element constituting an inverter has a short-circuit failure, the current of the failed phase cannot be controlled, and there is a risk that the motor output torque becomes excessive or the motor winding burns out. Therefore, a technique for interrupting the current of the failed phase at the time of a short-circuit failure using a fuse or the like is known.

[0003] Patent Document 1 describes an invention of a power conversion device in which a fuse is provided between a DC power supply and an inverter circuit, and when a failure of a switching element in the inverter circuit is detected, a switching element arranged in series with the failed switching element is turned on to allow a short-circuit current to flow and blow the fuse.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The power conversion device described in Patent Document 1 is configured to generate a short-circuit current by turning on a switching element arranged in series with a failed switching element for the purpose of preventing a cascading failure when the switching element fails, and to fuse a fuse arranged between a DC power supply and an inverter circuit. In this configuration, current flows through the switching elements of each phase via the same fuse. When a short-circuit fault occurs in any one of the switching elements, the fuses corresponding to all the switching elements will be fused regardless of the fault location. As a result, after the fuse is blown, the power supply cannot be supplied to the inverter circuit, so the load cannot be driven after the fault occurs.

Means for Solving the Problems

[0006] The present invention The first aspect The power conversion device according to the present invention includes a power conversion circuit in which at least three-phase upper and lower arm circuits in which switching elements are connected in series are connected in parallel, a plurality of fuses each connected in series with the switching elements of each phase of the power conversion circuit and fusing at a predetermined rated current or more, a short-circuit fault location determination unit that determines the short-circuit fault location of the switching element, and a fuse blowing current control unit that controls the driving of another switching element different from the switching element so that the current flowing through the switching element determined to be the short-circuit fault location by the short-circuit fault location determination unit becomes equal to or greater than the rated current of the fuse. , when the fuse blows, the current control unit controls the switching element of a different phase so that current flows through the load to the switching element of a different phase from the switching element determined to be the short-circuit fault location, and switches the switching element connected in series with the switching element determined to be the short-circuit fault location to the on state . The power conversion device according to the second aspect of the present invention includes a power conversion circuit in which at least three-phase upper and lower arm circuits with switching elements connected in series are connected in parallel, a plurality of fuses respectively connected in series with the switching elements of each phase of the power conversion circuit and fusing at a predetermined rated current or more, a short-circuit fault location determination unit that determines a short-circuit fault location of the switching element, and a current control unit during fuse blowing that controls the driving of another switching element different from the switching element determined to be the short-circuit fault location so that the current flowing through the switching element determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse. The power conversion circuit has a positive-side wiring connected to the positive electrode side of a DC power supply and a negative-side wiring connected to the negative electrode side of the DC power supply. The upper and lower arm circuits of each phase are respectively connected between the positive-side wiring and the negative-side wiring, and output lines connected to the windings of each phase of the motor are respectively connected between the switching element of the upper arm and the switching element of the lower arm. The plurality of fuses include an upper arm fuse connected in series with the switching element of the upper arm between the positive-side wiring and the output line, and a lower arm fuse connected in series with the switching element of the lower arm between the negative-side wiring and the output line, in the upper and lower arm circuits of each phase. When the temperature of another switching element different from the switching element determined to be the short-circuit fault location is less than a predetermined threshold value, the current control unit during fuse blowing sets the phase to which the switching element determined to be the short-circuit fault location belongs as a fault phase, turns off the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase, and controls the driving of the switching elements of each phase excluding the fault phase so that the current flowing through the switching element determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse. When the temperature of another switching element different from the switching element determined to be the short-circuit fault location is equal to or greater than the threshold value, the current control unit during fuse blowing turns on the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase, and after either the upper arm fuse or the lower arm fuse in the fault phase is blown, controls the current flowing through the other so that it becomes equal to or greater than the rated current of the fuse.Control the driving of other switching elements different from the switching element determined to be the short-circuit fault location. The present invention The third aspectThe drive device according to the present invention includes a power conversion device that outputs three-phase alternating current, and a rotating electric machine driven by the three-phase alternating current. The power conversion device includes a power conversion circuit in which at least three upper and lower arm circuits in which switching elements are connected in series are connected in parallel, a plurality of fuses respectively connected in series with the switching elements of each phase of the power conversion circuit and fusing at a predetermined rated current or more, a short-circuit fault location determination unit that determines a short-circuit fault location of the switching element, and a current control unit at the time of fuse melting that controls the driving of another switching element different from the switching element so that the current flowing through the switching element determined to be the short-circuit fault location by the short-circuit fault location determination unit becomes equal to or greater than the rated current of the fuse. , when the fuse blows, the current control unit controls the switching element of a different phase so that current flows through the load to the switching element of a different phase from the switching element determined to be the short-circuit fault location, and switches the switching element connected in series with the switching element determined to be the short-circuit fault location to the on state 。 The drive device according to the fourth aspect of the present invention includes a power conversion device that outputs three-phase alternating current and a rotating electric machine driven by the three-phase alternating current. The power conversion device includes a power conversion circuit in which at least three-phase upper and lower arm circuits connected in series with switching elements are connected in parallel, a plurality of fuses respectively connected in series with the switching elements of each phase of the power conversion circuit and melting at a predetermined rated current or more, a short-circuit fault location determination unit that determines a short-circuit fault location of the switching element, and a current control unit at the time of fuse melting that controls the driving of another switching element different from the switching element determined to be the short-circuit fault location so that the current flowing through the switching element determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse. The power conversion circuit has a positive-side wiring connected to the positive electrode side of a DC power supply and a negative-side wiring connected to the negative electrode side of the DC power supply. Each phase of the upper and lower arm circuits is connected between the positive-side wiring and the negative-side wiring, and output lines connected to the windings of each phase of the rotating electric machine are respectively connected between the switching element of the upper arm and the switching element of the lower arm. The plurality of fuses include an upper arm fuse connected in series with the switching element of the upper arm between the positive-side wiring and the output line and a lower arm fuse connected in series with the switching element of the lower arm between the negative-side wiring and the output line in each phase of the upper and lower arm circuits. When the temperature of another switching element different from the switching element determined to be the short-circuit fault location is less than a predetermined threshold value, the current control unit at the time of fuse melting sets the phase to which the switching element determined to be the short-circuit fault location belongs as a fault phase, turns off the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase, and controls the driving of the switching elements of each phase excluding the fault phase so that the current flowing through the switching element determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse. When the temperature of another switching element different from the switching element determined to be the short-circuit fault location is equal to or greater than the threshold value, the current control unit at the time of fuse melting turns on the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase, andAfter either the upper arm fuse or the lower arm fuse of the faulty phase is blown, the driving of another switching element different from the switching element determined to be the short-circuit fault location is controlled so that the current flowing through the other one becomes equal to or greater than the rated current of the fuse.

Advantages of the Invention

[0007] When a short-circuit fault occurs in the switching element, the fuse at the fault location can be surely melted.

Brief Description of the Drawings

[0008]

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Best Mode for Carrying Out the Invention

[0009] FIG. 1 is a diagram showing an example of a vehicle equipped with the drive device of the present invention. The vehicle 1 shown in FIG. 1 includes drive wheels 2 and non-drive wheels 3, and is equipped with a drive device 200. This drive device 200 is connected to an axle 4 with drive wheels 2 attached to both ends, and has a power conversion device 100 and a motor 190 (see FIG. 2) inside. Then, in response to the driver's operation of the accelerator pedal, the power conversion device 100 and the motor 190 are controlled to generate a driving force, and the driving force is transmitted to the axle 4. Thereby, the drive wheels 2 are driven to make the vehicle 1 travel. Further, a speed reducer may be arranged in the drive device, and the driving force of the motor 190 may be transmitted to the axle 4 via the speed reducer.

[0010] In FIG. 1, the front wheels of the vehicle 1 are drive wheels 2, the rear wheels are non-drive wheels 3, and the drive device 200 is connected to the axle 4 on the front wheel side. However, the rear wheels may be drive wheels and the drive device 200 may be connected to the axle on the rear wheel side. Further, all of the front and rear wheels may be drive wheels and the drive device 200 may be connected to each axle, or independent drive devices 200 may be installed and connected to the left and right drive wheels instead of the axles.

[0011] Subsequently, each embodiment of the power conversion device 100 and the drive device 200 will be described below.

Embodiment

[0012] FIG. 2 is a diagram showing a configuration example of the power conversion device 100 and the drive device 200 in the present embodiment. In the present embodiment, an example of a power conversion device and a drive device that fuse only the fuse of the faulty phase without fusing the fuse of the normal phase when a short-circuit fault of the power semiconductor occurs is shown.

[0013] The drive device 200 includes a power conversion device 100 and a motor 190. The motor 190 is a three-phase motor having three windings inside, and examples include a synchronous motor using permanent magnets or an induction motor not using permanent magnets. Further, an angle sensor (not shown) for measuring the electrical angle of the motor is mounted on the motor 190, and this angle sensor outputs the measured electrical angle as an angle sensor value θ to the power conversion device 100.

[0014] Around the drive device, there are an electronic control device (not shown), a DC power supply 210, and an abnormality notification device 220. The electronic control device notifies the drive device 200 of information such as a target torque. The DC power supply 210 is a power supply for driving the motor 190, and examples include a battery. The abnormality notification device 220 receives a failure notification signal from the drive device 200 and notifies the occupant of the occurrence of a failure. Examples of the failure notification method include lighting a lamp, generating a warning sound, and notifying by voice.

[0015] The power conversion device 100 converts DC power obtained from the DC power supply 210 into AC power to drive the motor 190. Further, the power conversion device 100 also has a function of converting the power of the motor 190 into DC power to charge the DC power supply 210. The power conversion device 100 includes a control circuit 10, a driver circuit 20, a power conversion circuit 30, a voltage sensor 40, and an AC current sensor 50 inside. The power conversion circuit 30 receives a drive signal 20a from the driver circuit 20, drives internal power semiconductors, and controls the current flowing through the motor 190. The internal configuration of the power conversion circuit 30 will be described first with reference to FIG. 3, and the internal configuration and other configurations of the control circuit 10 will be described later.

[0016] FIG. 3 is a diagram showing a configuration example of the power conversion circuit 30 and the motor 190 in this embodiment. The power conversion circuit 30 includes a smoothing capacitor 31, six power semiconductor elements 32, and six fuses 60 inside.

[0017] The smoothing capacitor 31 is a capacitor for smoothing the current generated by the on / off operation of the power semiconductor element 32 and suppressing the ripple of the DC current supplied from the DC power supply 210 to the power conversion circuit 30. For this smoothing capacitor 31, for example, an electrolytic capacitor or a film capacitor is used.

[0018] The power semiconductor element 32 is a switching element that switches on / off in response to the drive signal 20a input from the driver circuit 20, and performs the conversion between DC power and AC power. For this power semiconductor element 32, for example, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor) etc. are applicable. Also, the power semiconductor element 32 of this embodiment has a sense terminal 33. From the sense terminal 33, a certain ratio of the current flowing between the collector-emitter (drain-source) of the power semiconductor element 32, for example, 1 / 100 or 1 / 1000 of the current, is output as the sense current. The sense current is output from the power conversion circuit 30 to the driver circuit 20. In the following embodiments, an example using an IGBT as the power semiconductor element 32 will be described.

[0019] The six power semiconductor elements 32 are divided into two upper and lower ones for each phase, and the output is connected to the windings of each phase of the motor 190. Also, in this embodiment, the three upper power semiconductor elements 32 are collectively called the upper arm, and the three lower power semiconductor elements 32 are collectively called the lower arm. That is, in the power conversion circuit 30, for each phase (U phase, V phase, W phase) of the motor 190, an upper and lower arm circuit in which two power semiconductor elements 32 of the upper and lower arms are connected in series is provided. The power conversion circuit 30 has wirings respectively connected to the positive electrode side and the negative electrode side of the DC power supply 210, and the upper and lower arm circuits of each phase are connected in parallel between these wirings to be configured.

[0020] In this embodiment, the motor neutral point 191 is in a floating state, but it may be connected to ground (not shown). When connecting the motor neutral point 191 to ground, methods include direct grounding, resistance grounding, compensating reactor grounding, arc suppression reactor grounding, etc.

[0021] The six fuses 60 are arranged in series with the six power semiconductor elements 32 respectively. Each fuse 60 blows when a current equal to or greater than the fuse rated current flows for a certain period of time or more, cutting off the connection between the wiring on the positive or negative side of the DC power supply 210 and the output line connected to each phase winding of the motor 190.

[0022] In the following description, the fuses 60 corresponding to the power semiconductor elements 32 in the upper arm may be respectively referred to as "upper arm fuses", and the fuses 60 corresponding to the power semiconductor elements 32 in the lower arm may be respectively referred to as "lower arm fuses".

[0023] In this embodiment, fuses 60 are respectively arranged between the power semiconductor elements 32 and the wiring on the positive or negative side of the DC power supply 210. However, fuses 60 may also be arranged between the power semiconductor elements 32 and the output lines of each phase. As long as the fuses 60 are connected in series with the power semiconductor elements 32 of each phase and the fuses 60 blow when the power semiconductor elements 32 have a short - circuit fault, thereby cutting off the current flowing from the DC power supply 210 to the windings of each phase, the arrangement position of the fuses 60 does not matter. That is, in the upper and lower arm circuits of each phase, an upper arm fuse is connected in series with the power semiconductor element 32 in the upper arm between the wiring on the positive side of the DC power supply 210 and the output line to the motor 190, and a lower arm fuse is connected in series with the power semiconductor element 32 in the lower arm between the wiring on the negative side of the DC power supply 210 and the output line to the motor 190, then the fuses 60 can be arranged at any position.

[0024] Also, in this embodiment, a fuse 60 is used to cut off the current when the power semiconductor device 32 has a short-circuit fault. However, for example, a bus bar or wire bonding that melts when a current equal to or greater than a certain value flows may be used instead of the fuse. Generally, when a fuse is used, it is possible to easily design a circuit that provides a desired melting time when the power semiconductor device 32 has a short-circuit fault. On the other hand, when a bus bar or wire bonding is used, an additional element such as a fuse is not required, which is advantageous in terms of cost and size.

[0025] Returning to FIG. 2, the configuration of this embodiment will be described. The voltage sensor 40 is a sensor that measures the output voltage of the DC power supply 210, and outputs the measured voltage value to the control circuit 10 as the voltage sensor value 40a.

[0026] The AC current sensor 50 is a sensor that measures the AC current flowing through each phase (U-phase, V-phase, W-phase) of the motor 190, and outputs the measured AC current of each phase to the control circuit 10 as the AC current value 50a. In this embodiment, three AC current sensors 50 are provided, one for each phase. However, the AC current sensors may be provided only for two phases. In this case, since the relationship U-phase current + V-phase current + W-phase current = 0 holds, the control circuit 10 calculates the AC current sensor value for the remaining one phase by calculation. In this embodiment, the current flowing in the direction from the power conversion circuit 30 to the motor 190 is treated as a positive current, and the current flowing in the direction from the motor 190 to the power conversion circuit 30 is treated as a negative current.

[0027] The driver circuit 20 receives the PWM (Pulse Width Modulation) signal 16a output by the PWM signal generation unit 16, which will be described later, and outputs a drive signal 20a for switching the on / off of the power semiconductor device 32. Also, the driver circuit 20 uses the sense current 33a output from the power semiconductor device 32 to detect the occurrence of a short-circuit fault in the power semiconductor device 32, and outputs a short-circuit fault detection signal 20b to the control circuit 10.

[0028] Normally, the PWM signal 16a is generated so that the upper and lower power semiconductor elements 32 do not turn on simultaneously. However, if a short-circuit fault occurs in the power semiconductor element 32, the upper and lower power semiconductor elements 32 can turn on simultaneously. When the upper and lower power semiconductor elements 32 turn on simultaneously, a large through-current flows through the power semiconductor element 32. The driver circuit 20 monitors whether the sense current 33a of each power semiconductor element 32 is equal to or greater than a certain threshold value. When the sense current 33a is equal to or greater than a certain value, it is determined that the power semiconductor element 32 in the corresponding phase has a short-circuit fault. Then, the driver circuit 20 outputs a short-circuit fault detection signal 20b separated for each phase.

[0029] In this embodiment, the short-circuit fault of the power semiconductor element 32 is determined using the sense current 33a of the power semiconductor element 32. However, other methods may be used to detect the short-circuit fault of the power semiconductor element 32. For example, a shunt resistor for current measurement may be arranged on the collector side or the emitter side of the power semiconductor element 32, and the current value flowing through the shunt resistor may be measured to detect the short-circuit fault of the power semiconductor element 32. Also, since the collector-emitter voltage of the power semiconductor element 32 increases according to the flowing current, there is also a method of measuring the collector-emitter voltage to detect the short-circuit fault of the power semiconductor element 32.

[0030] The control circuit 10 communicates with an external electronic control device (not shown) and receives the target torque T* of the motor 190 from the electronic control device. When the power conversion device 100 is normal, the control circuit 10 outputs the PWM signal 16a so as to control the current of each phase output from the power conversion device 100 to a predetermined value based on this target torque T*, and drives the power conversion circuit 30 via the driver circuit 20. Further, when it is determined that a fault has occurred inside the power conversion device 100, the control circuit 10 outputs an abnormality notification signal to the external abnormality notification device 220.

[0031] The control circuit 10 has a CPU, a RAM, a ROM, and a communication circuit inside (none of which are shown). This ROM may be an electrically rewritable EEPROM (Electrically Erasable Programmable ROM) or a flash ROM. Further, the control circuit 10 may have a logic circuit configured using hardware such as an FPGA (Field Programmable Gate Array).

[0032] Also, the control circuit 10 has functional blocks of a motor speed calculation unit 11, a target current calculation unit 12 during torque control, a current control unit 13 during torque control, a target current calculation unit 14 during fuse blowing, a current control unit 15 during fuse blowing, a PWM signal generation unit 16, a short - circuit fault location determination unit 17, a fuse blowing determination unit 18, and a state determination unit 19. These functional blocks may be realized, for example, by the CPU in the control circuit 10 executing a predetermined program, or a part or all of them may be realized by hardware such as an FPGA.

[0033] The motor speed calculation unit 11 calculates the motor rotation speed from the change in the angle sensor value θ of the motor, and outputs the calculated motor speed value 11a to the target current calculation unit 12 during torque control.

[0034] The target current calculation unit 12 during torque control uses the target torque T*, the voltage sensor value 40a, and the motor speed value 11a output by the motor speed calculation unit 11 to output a target current value 12a to the current control unit 13 during torque control. The target current value 12a is calculated as the current value that should flow through the motor 190 so that the motor 190 outputs the same torque as the target torque T*. The target current value 12a is represented, for example, in the form of a d - axis target current value and a q - axis target current value.

[0035] The current control unit 13 during torque control uses the target current value 12a output by the target current calculation unit 12 during torque control, the motor angle sensor value θ, the AC current sensor value 50a of each phase, and the voltage sensor value 40a to calculate the duty value 13a of each phase, and outputs the duty value 13a to the PWM signal generation unit 16.

[0036] When the fuse blows, the target current calculation unit 14 determines the target current for each phase during fuse blowing control based on the short - circuit fault location information 17a of the power semiconductor element 32 output by the short - circuit fault location determination unit 17, and outputs this target current value 14a to the current control unit 15 during fuse blowing. The details of the method for determining this target current value 14a will be described later.

[0037] The current control unit 15 during fuse blowing uses the target current value 14a output by the target current calculation unit 14 during fuse blowing, the motor angle sensor value θ, the AC current sensor value 50a for each phase, the voltage sensor value 40a, and the short - circuit fault location information 17a of the power semiconductor element 32 to calculate the duty value 15a for each phase and outputs it to the PWM signal generation unit 16.

[0038] The PWM signal generation unit 16 switches the signal output to the driver circuit 20 according to the internal state 19a output from the state determination unit 19. The PWM signal generation unit 16 has a timer internally. When the internal state 19a is in the "normal state", it uses this timer value and the duty 13a for each phase output by the current control unit 13 during torque control to output the PWM signal 16a to the driver circuit 20. When the internal state 19a is in the "power semiconductor element short - circuit fault state" described later, the PWM signal generation unit 16 uses the timer value and the duty 15a for each phase output by the current control unit 15 during fuse blowing to output the PWM signal 16a to the driver circuit 20. When the internal state 19a is in the "state after fuse blowing" described later, the PWM signal generation unit 16 outputs a PWM signal 16a to the driver circuit 20 such that the motor 190 is not driven. A state where the motor 190 is not driven is, for example, a state where all six power semiconductor elements 32 in the power conversion circuit 30 are turned off (referred to as a free - wheel state in this embodiment).

[0039] The short - circuit fault location determination unit 17 determines the short - circuit fault location of the power semiconductor element 32 based on the PWM signal 16a and the short - circuit fault detection signal 20b output by the driver circuit 20. Since the short - circuit fault detection signal 20b output by the driver circuit 20 is separated for each phase, it is possible to identify which phase the fault has occurred in, but it is not possible to identify which of the upper and lower arms has failed. Therefore, by comparing the timing when the short - circuit fault detection signal 20b is output with the state of the PWM signal 16a, it is determined that a short - circuit fault has occurred in the arm of the PWM signal 16a of the upper and lower arms of the phase where the fault has occurred and where the short - circuit fault detection signal 20b is in the OFF state. This is because normally the upper and lower power semiconductor elements 32 do not turn on simultaneously, so when a short - circuit fault of the power semiconductor element 32 is detected, it is considered that a short - circuit fault has occurred in the power semiconductor element 32 that should originally be in the OFF state, and the upper and lower power semiconductor elements 32 have turned on simultaneously. The short - circuit fault location determination unit 17 outputs the short - circuit fault location information 17a of the power semiconductor element 32 to the fuse - blowing target current calculation unit 14, the fuse - blowing current control unit 15, the fuse - blowing determination unit 18, the state determination unit 19, and the external abnormality notification device 220.

[0040] The fuse - blowing determination unit 18 determines whether the fuse 60 of the faulty phase has blown based on the short - circuit fault location information 17a output from the short - circuit fault location determination unit 17 and the AC current sensor value 50a of each phase, and outputs a fuse - blowing determination signal 18a to the state determination unit 19. When a short - circuit fault of the power semiconductor element 32 is detected, the control circuit 10 controls the current of each phase so as to blow the fuse 60 at the fault location. Therefore, a current exceeding the rated current of the fuse 60 flows through the faulty phase, but when the fuse 60 at the fault location blows, no current flows through the faulty phase. The fuse - blowing determination unit 18 monitors the AC current sensor value 50a of the phase where the short - circuit fault has occurred, and determines that the fuse 60 at the fault location has blown when the state where the absolute value of the AC current sensor value 50a is less than the threshold continues for a certain period of time or more.

[0041] The state determination unit 19 determines whether the state of the power conversion device 100 is in any one of the "normal state", "power semiconductor element short-circuit fault state", and "state after fuse blowing" based on the short-circuit fault location information 17a of the power semiconductor element 32 output by the short-circuit fault location determination unit 17 and the fuse blowing determination signal 18a output by the fuse blowing determination unit 18. Then, it outputs the current state (19a) to the PWM signal generation unit 16.

[0042] Figure 4 is a table showing the internal state determination of the state determination unit 19 in this embodiment. The state determination unit 19 determines the next state from the current state and the occurrence events at regular intervals, and updates the next state to the current state. The initial state is the "normal state". First, when the current state of the state determination unit 19 is the "normal state" and it receives the short-circuit fault location information 17a of the power semiconductor element 32 from the short-circuit fault location determination unit 17, it changes the next state to the "power semiconductor element short-circuit fault state". Otherwise, the next state remains the "normal state". Also, when the current state of the state determination unit 19 is the "power semiconductor element short-circuit fault state" and it receives the fuse blowing determination signal 18a from the fuse blowing determination unit 18, it changes the next state to the "state after fuse blowing". Otherwise, the next state remains the "power semiconductor element short-circuit fault state". When the current state of the state determination unit 19 is the "state after fuse blowing", the next state remains the "state after fuse blowing".

[0043] For current control during torque control, first, in the target current calculation unit 12 during torque control shown in FIG. 2, the d-axis target current value and the q-axis target current value corresponding to the target torque T* are determined. Next, in the current control unit 13 during torque control, the duty values 13a of each phase are calculated so as to achieve the d-axis target current value and the q-axis target current value determined by the target current calculation unit 12 during torque control. Then, the PWM signal generation unit 16 generates the PWM signals 16a of each phase according to the duty values 13a of each phase calculated by the current control unit 13 during torque control.

[0044] During torque control, the current control unit 13 converts the three-phase AC current sensor values 50a output from the AC current sensor 50 into current values on the d-axis and q-axis using the formula in [Equation 1]. In [Equation 1], Iu, Iv, and Iw are the AC current sensor values of the U-phase, V-phase, and W-phase respectively, and θ is the angle sensor value. Also, Id is the current value on the d-axis after conversion, and Iq is the current value on the q-axis after conversion.

[0045]

Equation

[0046] Next, during torque control, the current control unit 13 calculates the differences between the d-axis current and the d-axis target current value, and between the q-axis current and the q-axis target current value. Then, the current control unit 13 performs feedback control on the d-axis current difference and the q-axis current difference to determine the d-axis target voltage value and the q-axis target voltage value. The current control unit 13 converts this d-axis target voltage value and q-axis target voltage value into the form of the α-axis target voltage value and the β-axis target voltage value using [Equation 2]. In [Equation 2], Vd is the d-axis target voltage value, Vq is the q-axis target voltage value, θ is the angle sensor value, Vα is the α-axis target voltage value, and Vβ is the β-axis target voltage value.

[0047]

Equation

[0048] Then, the current control unit 13 converts the α-axis target voltage value and the β-axis target voltage value into the target voltage values of each phase of the U-phase / V-phase / W-phase using [Equation 3]. In [Equation 3], Vα is the α-axis target voltage value, Vβ is the β-axis target voltage value, Vu is the U-phase target voltage value, Vv is the V-phase target voltage value, and Vw is the W-phase target voltage value.

[0049]

Equation

[0050] Finally, during torque control, the current control unit 13 calculates the duty value 13a for each phase from the target voltage value for each phase and the voltage sensor value 40a.

[0051] During fuse blowing, for current control, first, in the target current calculation unit 14 during fuse blowing, the target current value 14a for each phase during fuse blowing (U-phase target current value (Iu), V-phase target current value (Iv), W-phase target current value (Iw)) is determined. Then, using the conversion formula in [Equation 1], the target current value 14a for each phase is converted into the d-axis target current value (Id) and the q-axis target current value (Iq). This conversion can be implemented by substituting Iu for the U-phase target current value, Iv for the V-phase target current value, Iw for the W-phase target current value, Id for the d-axis current target value, and Iq for the q-axis target current value in the conversion formula of [Equation 1].

[0052] Next, in the current control unit 15 during fuse blowing, the duty value 15a for each phase is calculated so as to achieve the d-axis target current value and the q-axis target current value determined by the target current calculation unit 14 during fuse blowing. Then, the PWM signal generation unit 16 generates the PWM signal 16a for each phase according to the duty value 15a for each phase calculated by the current control unit 15 during fuse blowing.

[0053] FIG. 5 is an example of setting the target current value 14a for each phase during fuse blowing. In fuse blowing control, when a power semiconductor element 32 of a certain phase has a short-circuit fault, control is performed so that a current equal to or greater than the fuse rated current flows through the faulty phase. Therefore, the target current value 14a of the faulty phase is set such that the absolute value of the target current value is equal to or greater than the fuse rated current. Also, the target current value 14a for each phase is set so as to satisfy U-phase target current value + V-phase target current value + W-phase target current value = 0.

[0054] In addition, when the power semiconductor device 32 in the upper arm experiences a short - circuit failure, the current in the faulty phase tends to flow from the power conversion circuit 30 towards the motor 190. Therefore, when calculating the target current at the time of fuse blowing, the target current value for the faulty phase is set to a positive value by the target current calculation unit 14. Conversely, when the power semiconductor device 32 in the lower arm experiences a short - circuit failure, the current in the faulty phase tends to flow from the motor 190 towards the power conversion circuit 30. Therefore, the target current calculation unit 14 sets the target current value for the faulty phase to a negative value.

[0055] The target current value for a normal phase may be set either above or below the fuse rated current. When the target current value for a normal phase is set below the fuse rated current, it is possible to prevent the fuse in the normal phase from being accidentally blown. When the target current value for a normal phase is set above the fuse rated current, there is a possibility that the fuse in the normal phase may be accidentally blown. However, even in such a case, by adjusting the target current value flowing through the faulty phase and the target current value flowing through the normal phase, the fuse in the faulty phase can be blown earlier than the fuse in the normal phase. Also, when the target current value for a normal phase is set above the fuse rated current, the value of the target current flowing through the faulty phase can be increased, so that the fuse in the faulty phase can be blown earlier.

[0056] Based on these considerations, in the example of FIG. 5, when a short - circuit failure occurs in the upper arm of the U - phase, the target current value 14a for the U - phase is set to 1.8 times the fuse rated current, and the target current values 14a for the V - phase and W - phase are set to - 0.9 times the fuse rated current.

[0057] The reason for setting the target current values 14a for the V - phase and W - phase to - 0.9 times the fuse rated current instead of - 1.0 times the fuse rated current is that the actual current flowing during the control process may exceed the target current value. Therefore, in anticipation of this, the target current value is set slightly lower. Note that this control error difference does not necessarily have to be 0.1 times the fuse rated current.

[0058] Similarly, when a short-circuit fault occurs in the U-phase lower arm, the target current value 14a of the U-phase is set to -1.8 times the fuse rated current, and the target current values 14a of the V-phase and W-phase are set to 0.9 times the fuse rated current.

[0059] Also, when a short-circuit fault occurs in the V-phase upper arm, the target current value 14a of the V-phase is set to 1.8 times the fuse rated current, and the target current values 14a of the U-phase and W-phase are set to -0.9 times the fuse rated current. When a short-circuit fault occurs in the V-phase lower arm, the target current value 14a of the V-phase is set to -1.8 times the fuse rated current, and the target current values 14a of the U-phase and W-phase are set to 0.9 times the fuse rated current.

[0060] Also, when a short-circuit fault occurs in the W-phase upper arm, the target current value 14a of the W-phase is set to 1.8 times the fuse rated current, and the target current values 14a of the U-phase and V-phase are set to -0.9 times the fuse rated current. When a short-circuit fault occurs in the W-phase lower arm, the target current value 14a of the W-phase is set to -1.8 times the fuse rated current, and the target current values 14a of the U-phase and V-phase are set to 0.9 times the fuse rated current.

[0061] Note that in FIG. 5, the target current values 14a of the normal two phases are set to the same value and in the same direction, but it is not necessarily required to set the target current values 14a to the same value and in the same direction. However, if the target current values 14a of the normal two phases are set in the same direction and the absolute values of the target current values 14a of the normal two phases are increased, the absolute value of the target current value 14a of the faulty phase can be made larger. Thereby, a large current can be passed through the faulty phase, and the fuse 60 of the faulty phase can be blown in a shorter time.

[0062] The calculation of the duty value in the fuse blowout current control unit 15 is basically carried out in the same procedure as the current control unit 13 during torque control. However, there are two points different from the current control unit 13 during torque control. One of them is to control the upper and lower opposite power semiconductor elements 32 in the same phase as the short-circuited power semiconductor element 32 to be in the off state.

[0063] When the upper and lower opposite power semiconductor devices 32 in the same phase as the short-circuited power semiconductor device 32 are turned on, a through current flows between the upper and lower power modules of the faulty phase, and there is a risk of accidentally blowing the fuse 60 corresponding to the power semiconductor device 32 on the upper and lower opposite side of the faulty power semiconductor device 32. To prevent this, in this embodiment, the upper and lower opposite power semiconductor devices 32 in the same phase as the short-circuited power semiconductor device 32 are kept off.

[0064] Another different point is to correct the target voltage in the conversion part from the α-axis target voltage value (Vα) and the β-axis target voltage value (Vβ) to the U-phase target voltage value (Vu), the V-phase target voltage value (Vv), and the W-phase target voltage value (Vw).

[0065] For example, when a short-circuit fault occurs in the power semiconductor device 32 of the upper arm of the U-phase and the power semiconductor device 32 of the lower arm of the U-phase is in the off state, assuming that the voltage of the DC power supply 210 is Vdc, the voltage output from the upper and lower arm circuits of the U-phase is fixed at 1 / 2·Vdc. Also, for example, when a short-circuit fault occurs in the power semiconductor device 32 of the lower arm of the U-phase and the power semiconductor device 32 of the upper arm of the U-phase is in the off state, the voltage output from the upper and lower arm circuits of the U-phase is fixed at -1 / 2·Vdc. Therefore, even if the target voltages of the normal U-phase, V-phase, and W-phase are converted, the power conversion circuit 30 cannot output the voltage as the target voltage. Therefore, it is necessary to calculate the target voltages of the remaining two phases in consideration of the deviation of the output voltage of the faulty phase so that the voltage corresponding to the same α-axis target voltage value (Vα) and β-axis target voltage value (Vβ) as before the fault can be output even after the fault occurs.

[0066] When the power semiconductor device 32 in the U-phase has a short-circuit fault, the target voltage values of the V-phase and W-phase are calculated by [Equation 4]. Here, when the voltage of the DC power supply 210 is Vdc, the value of the U-phase target voltage value (Vu) is set to 1 / 2·Vdc when the power semiconductor device 32 in the upper arm of the U-phase has a short-circuit fault, and is set to -1 / 2·Vdc when the power semiconductor device 32 in the lower arm of the U-phase has a short-circuit fault. By setting the U-phase target voltage value in this way, the power semiconductor device 32 on the short-circuit fault side of the U-phase is always turned on, and the power semiconductor device 32 on the non-short-circuit fault side of the U-phase is always controlled to be in the off state.

[0067]

Equation

[0068] When the power semiconductor device 32 in the V-phase has a short-circuit fault, the target voltage values of the U-phase and W-phase are calculated by [Equation 5]. Here, when the voltage of the DC power supply 210 is Vdc, the value of the V-phase target voltage value (Vv) is set to 1 / 2·Vdc when the power semiconductor device 32 in the upper arm of the V-phase has a short-circuit fault, and is set to -1 / 2·Vdc when the power semiconductor device 32 in the lower arm of the V-phase has a short-circuit fault. By setting the V-phase target voltage value in this way, the power semiconductor device 32 on the short-circuit fault side of the V-phase is always turned on, and the power semiconductor device 32 on the non-short-circuit fault side of the V-phase is always controlled to be in the off state.

[0069]

Equation

[0070] When the power semiconductor device 32 in the W phase has a short - circuit fault, the target voltage values of the U phase and the V phase are calculated by [Equation 6]. Here, when the voltage of the DC power supply 210 is Vdc, the value of the W - phase target voltage value (Vw) is set to 1 / 2·Vdc when the power semiconductor device 32 in the upper arm of the W phase has a short - circuit fault, and is set to - 1 / 2·Vdc when the power semiconductor device 32 in the lower arm of the W phase has a short - circuit fault. By setting the W - phase target voltage value in this way, the power semiconductor device 32 on the short - circuit - fault side of the W phase is always turned on, and the power semiconductor device 32 on the non - short - circuit - fault side of the W phase is always controlled to be in the off state.

[0071]

Equation

[0072] FIG. 6 is a diagram showing an example of the current waveform during fuse - blowing control in this embodiment. In the example of FIG. 6, when the power semiconductor device 32 in the upper arm of the U phase has a short - circuit fault, the U - phase target current value is set to 1.4 times the fuse - rated current, the V - phase target current value is set to - 0.9 times the fuse - rated current, and the W - phase target current value is set to - 0.5 times the fuse - rated current, respectively. In the example of FIG. 6, the current flowing through each phase is almost the same as the target current value, and the current value of the faulty U phase is equal to or greater than the fuse - rated current, while the currents of the normal V phase and W phase are less than the fuse - rated current, and they can be controlled respectively.

[0073] Note that in the example shown in FIG. 6, in order to explain the fuse - blowing control after the short - circuit fault of the power semiconductor device occurs, the figure shows that the current during fuse - blowing continues to flow even after the short - circuit fault occurs. However, in reality, after a current equal to or greater than the fuse - rated current starts to flow through the U phase and a predetermined time has elapsed, the fuse in the U phase blows and the system transitions to the free - wheeling state. Also, although different target current values are set so that the current waveforms of the V - phase current and the W - phase current do not overlap on the drawing, of course, the target current values can be set as in the example shown in FIG. 5, or they can be set to other values.

[0074] FIG. 7 is an example of a control flowchart in this embodiment. In this embodiment, the control circuit 10 shown in FIG. 2 periodically performs the control of FIG. 7 at regular intervals.

[0075] First, in the process of step S100, the control circuit 10 determines whether the internal state 19a output from the state determination unit 19 is in the "normal state". If the internal state 19a is in the "normal state", the process proceeds to step S101; otherwise, the process proceeds to step S104.

[0076] In the process of step S101, the control circuit 10 performs current control according to the torque command value. More specifically, as described above, the target current calculation unit 12 for torque control generates a target current value 12a corresponding to the target torque T*, and the current control unit 13 for torque control generates a duty value 13a for each phase corresponding to this target current value 12a. Then, the PWM signal generation unit 16 generates a PWM signal 16a based on the duty value 13a for each phase and outputs the PWM signal 16a to the driver circuit 20.

[0077] Next, in the process of step S102, the short-circuit fault location determination unit 17 determines whether a short-circuit fault has occurred in any of the power semiconductor elements 32 based on the short-circuit fault detection signal 20b output from the driver circuit 20. If a short-circuit fault is detected, the short-circuit fault location is determined as described above using the PWM signal 16a, and after outputting the short-circuit fault location information 17a based on the determination result, the process proceeds to step S103. In the process of step S103, the state determination unit 19 determines that the current state of the power conversion device 100 is in the "power semiconductor short-circuit fault state" and updates the internal state 19a. After executing the process of step S103, the control circuit 10 ends the control flowchart of FIG. 7.

[0078] On the other hand, if no short-circuit fault is detected for any of the power semiconductor devices 32, the control circuit 10 does not execute the process of step S103 and ends the control flowchart of FIG. 7. In this case, the short-circuit fault location determination unit 17 does not output the short-circuit fault location information 17a, and the state determination unit 19 maintains the internal state 19a as the "normal state".

[0079] If it is determined in step S100 that the internal state 19a output from the state determination unit 19 is not the "normal state", in the process of step S104, the control circuit 10 determines whether the internal state 19a is the "power semiconductor device short-circuit fault state". If the internal state 19a is the "power semiconductor device short-circuit fault state", the process proceeds to step S105; otherwise, the process proceeds to step S108.

[0080] In the process of step S105, the control circuit 10 performs fuse blowing control. More specifically, as described above, the target current calculation unit 14 for fuse blowing generates the target current value 14a for each phase based on the short-circuit fault location information 17a, and the current control unit 15 for fuse blowing generates the duty value 15a for each phase corresponding to this target current value 14a. Then, the PWM signal generation unit 16 generates the PWM signal 16a based on the duty value 15a for each phase and outputs the PWM signal 16a to the driver circuit 20. As a result, the driving of the other power semiconductor devices 32 is controlled so that the current flowing through the power semiconductor device 32 determined to be the short-circuit fault location in the short-circuit fault location determination unit 17 exceeds the fuse rated current.

[0081] Next, in the process of step S106, the fuse blow determination unit 18 determines whether or not the fuse 60 of the faulty phase has blown based on the AC current sensor value 50a for the phase current of the faulty phase. If it is detected that the fuse 60 of the faulty phase has blown, after outputting the fuse blow determination signal 18a, the process proceeds to step S107. In the process of step S107, the state determination unit 19 determines that the current state of the power conversion device 100 is the "state after fuse blow" and updates the internal state 19a. After executing the process of step S107, the control circuit 10 ends the control flowchart of FIG. 7.

[0082] On the other hand, if it is not detected that the fuse 60 of the faulty phase has blown, the control circuit 10 does not execute the process of step S107 and ends the control flowchart of FIG. 7. In this case, the fuse blow determination unit 18 does not output the fuse blow determination signal 18a, and the state determination unit 19 maintains the internal state 19a as the "short-circuit fault state of the power semiconductor element".

[0083] If it is determined in step S104 that the internal state 19a output from the state determination unit 19 is not the "short-circuit fault state of the power semiconductor element", that is, if the internal state 19a is the "state after fuse blow", in the process of step S108, the control circuit 10 determines that the fuse 60 of the faulty phase has blown. Then, in order for the power conversion circuit 30 to enter the freewheel state, the PWM signal generation unit 16 outputs the PWM signal 16a to the driver circuit 20, etc., to stop driving the motor 190.

[0084] As described above, in this embodiment, when a short-circuit fault occurs in any of the power semiconductor elements 32, by controlling the current flowing through the power semiconductor element 32 at the fault location to be equal to or greater than the rated current of the fuse 60, only the fuse 60 of the faulty phase can be blown without blowing the fuses 60 of the normal two phases. Further, after the fuse of the faulty phase has blown, by putting the other power semiconductor elements 32 in the power conversion circuit 30 into the freewheel state, the state of not driving the motor 190 can be maintained.

Embodiment

[0085] In this embodiment, an example of a power conversion device 100 and a drive device 200 is shown, in which when a short - circuit fault occurs in the power semiconductor device 32, only the fuse of the faulty phase is blown in a shorter time without blowing the fuse 60 of the normal phase, and the drive of the motor 190 can be continued even after the fuse is blown.

[0086] FIG. 8 is a diagram showing a configuration example of the power conversion device 100 and the drive device 200 in this embodiment. The power conversion device 100 and the drive device 200 in this embodiment have a power conversion circuit 302 with a configuration different from that of the power conversion circuit 30 in the first embodiment. In addition, the control circuit 10 in the power conversion device 100 in this embodiment has a post - fuse current control unit 312 in addition to each functional block in the first embodiment, and also has a fuse - blowing - time target current calculation unit 142, a fuse - blowing - time current control unit 152, and a PWM signal generation unit 162, which are different from the fuse - blowing - time target current calculation unit 14, the fuse - blowing - time current control unit 15, and the PWM signal generation unit 16 in the first embodiment, respectively. Explanation of the components common to the first embodiment is omitted.

[0087] FIG. 9 is a diagram showing a configuration example of the power conversion circuit 302 and the motor 190 in this embodiment. The power conversion circuit 302 in this embodiment has an upper and lower arm circuit for driving the motor neutral - point voltage in addition to the circuit in the first embodiment. This upper and lower arm circuit for driving the motor neutral - point voltage has two power semiconductor devices 32 of the upper and lower arms connected in series, similar to the upper and lower arm circuits of each phase, and fuses 60 (upper - arm fuse and lower - arm fuse) arranged in series with these power semiconductor devices 32, respectively. In addition, the output of this upper and lower arm circuit for driving the motor neutral - point voltage is connected to the neutral point 191 of the motor 190.

[0088] The driver circuit 20 in this embodiment has a circuit for driving each power semiconductor device 32 of the upper and lower arm circuits for driving the motor neutral - point voltage connected to the neutral point 191 in addition to the circuit in the first embodiment.

[0089] In this embodiment as well, similar to Embodiment 1, fuses 60 are respectively arranged between the power semiconductor element 32 and the wiring on the positive or negative side of the DC power supply 210. However, fuses 60 may also be arranged between the power semiconductor element 32 and the output line of each phase or the connection line of the neutral point 191. As long as the fuses 60 are connected in series with the power semiconductor elements 32 for driving each phase or the motor neutral point voltage and the fuses 60 are blown when the power semiconductor elements 32 have a short - circuit fault, thereby blocking the current flowing from the DC power supply 210 to the windings of each phase, the arrangement position of the fuses 60 does not matter. That is, in the upper and lower arm circuits for driving each phase and the motor neutral point voltage, an upper - arm fuse is connected in series with the power semiconductor element 32 of the upper arm between the wiring on the positive side of the DC power supply 210 and the output line to the motor 190 or the connection line of the neutral point 191, and a lower - arm fuse is connected in series with the power semiconductor element 32 of the lower arm between the wiring on the negative side of the DC power supply 210 and the output line to the motor 190 or the connection line of the neutral point 191, then the fuses 60 can be arranged at any position.

[0090] After the fuse in FIG. 8 is blown, the current control unit 312 calculates the duty values 312a of each phase and the motor neutral point using the target current value 12a output by the target current calculation unit 12 during torque control, the motor angle sensor value θ, the AC current sensor values 50a of each phase, and the voltage sensor value 40a, and outputs them to the PWM signal generation unit 162. The specific control of the current control unit 312 after the fuse is blown will be described later.

[0091] The PWM signal generation unit 162 of this embodiment switches the signal output to the driver circuit 20 according to the internal state 19a output from the state determination unit 19. When the internal state 19a is in the "normal state", the PWM signal generation unit 162 generates a PWM signal 162a using the timer value and the duty value 13a of each phase output by the torque control current control unit 13, and outputs it to the driver circuit 20. When the internal state 19a is in the "power semiconductor element short-circuit fault state", the PWM signal generation unit 162 generates a PWM signal 162a using the timer value and the duty values 152a of each phase and the motor neutral point output by the fuse blowing current control unit 15, and outputs it to the driver circuit 20. When the internal state 19a is in the "state after fuse blowing", the PWM signal generation unit 162 generates a PWM signal 162a using the timer value and the duty values 312a of each phase and the motor neutral point output by the current control unit 312 after fuse blowing, and outputs it to the driver circuit 20.

[0092] Next, the current control during fuse blowing control in this embodiment will be described. During the fuse blowing control in this embodiment, in addition to the current of each phase, the current flowing between the power semiconductor element 32 for driving the motor neutral point voltage and the neutral point 191 of the motor 190 (hereinafter referred to as the motor neutral point current) is also controlled. Therefore, the target current calculation unit 142 during fuse blowing in this embodiment sets a target current for the motor neutral point current (hereinafter referred to as the neutral point target current) in addition to the target current of each phase.

[0093] FIG. 10 is a diagram showing an example of setting the target current 142a by the target current calculation unit 142 during fuse blowing in this embodiment. Also in this embodiment, similar to Embodiment 1, the absolute value of the target current of the short-circuited phase is set to be equal to or greater than the fuse rated current. When setting the target current values 142a of each phase and the neutral point, it is set so as to satisfy U-phase target current value + V-phase target current value + W-phase target current value + neutral point target current = 0.

[0094] Here, the absolute value of the neutral point target current may be set to less than the rated current of fuse 60, or may be set to be equal to or greater than the rated current of fuse 60. Also, the neutral point target current is set to be in the opposite direction to the target current of the faulty phase. By making the neutral point target current in the opposite direction to the target current of the faulty phase, the absolute value of the target current of the faulty phase can be increased, and a larger current can be passed through the fuse 60 of the faulty phase to blow it in a short time.

[0095] The target current calculation unit 142 for fuse blowing in this embodiment converts the set target currents of each phase and the neutral point into a d-axis target current value (Id), a q-axis target current value (Iq), and a zero-phase target current value (Iz) using [Equation 7], and outputs these values to the current control unit 152 for fuse blowing. In this embodiment, since the neutral point target current is set, the sum of the U-phase target current + V-phase target current + W-phase target current is not equal to 0. Therefore, unlike in the first embodiment, the zero-phase target current value is also calculated.

[0096]

Equation

[0097] When the fuse in this embodiment blows, the current control unit 152 calculates the duty of each phase in the same manner as in the first embodiment. Also, in this embodiment, since it is necessary to control the on / off of the power semiconductor element 32 for driving the motor neutral point, the duty value for the motor neutral point is also calculated. The duty value for the motor neutral point is calculated as follows. First, the current control unit 152 for fuse blowing converts the three-phase AC current sensor values 50a output from the AC current sensor 50 into zero-phase current values using the motor angle sensor value θ. Next, the current control unit 152 for fuse blowing takes the difference between this zero-phase current and the zero-phase target current value. Then, the current control unit 152 for fuse blowing performs feedback control on the zero-phase current difference to determine the zero-phase target voltage value. The current control unit 152 for fuse blowing calculates the neutral point target voltage value (Vn) from the zero-phase target voltage (Vz) and the target voltage values (Vu, Vv, Vw) of each phase using the formula [Equation 8]. At this time, when a short-circuit fault occurs in the phase of the power semiconductor element 32, if the upper arm has a short-circuit fault, the target voltage value of that phase is calculated as 1 / 2·Vdc, and if the lower arm has a short-circuit fault, it is calculated as -1 / 2·Vdc, where Vdc is the voltage of the DC power supply 210. Finally, the current control unit 152 for fuse blowing calculates the duty value of the motor neutral point from the neutral point target voltage value and the voltage sensor value.

[0098]

Equation

[0099] FIG. 11 is a diagram showing an example of the current waveform during fuse blowing control in this embodiment. In the example of FIG. 11, when a short-circuit fault occurs in the power semiconductor element 32 of the upper arm of the U phase, the target current value of the U phase is set to 2.1 times the fuse rated current, the target current value of the V phase is set to -0.9 times the fuse rated current, the target current value of the W phase is set to -0.5 times the fuse rated current, and the target current value of the neutral point is set to -0.7 times the fuse rated current.

[0100] In the example of FIG. 11, the current of each phase and the neutral point current are almost the same as the target current value, and the current value of the faulty U phase can be controlled to be equal to or higher than the fuse rated current, while the currents of the normal V and W phases are less than the fuse rated current. Also, by controlling the neutral point current to be in the opposite direction to the current of the faulty U phase, the absolute value of the U phase current can be increased compared to the current waveform of the first embodiment.

[0101] Next, the current control after fuse blowing in this embodiment will be described. When the fuse 60 of the phase where the short-circuit fault has occurred blows, no current flows through that phase, and it becomes the same state as an open phase. At this time, by controlling the on / off of the power semiconductor elements 32 of the remaining two phases and the power semiconductor element 32 for driving the motor neutral point voltage so that the current phase difference of the remaining two phases becomes 60 degrees, torque control with suppressed torque ripple can be performed.

[0102] FIG. 12 is a diagram showing the current phases of the remaining two phases after fuse blowing. Note that FIG. 12 is an example of a case where the current phase of the V phase lags 120 degrees behind the current phase of the U phase and the current phase of the W phase leads 120 degrees ahead of the current phase of the U phase during normal operation. After the fuse of the U phase blows, the current is controlled so that the current phase of the W phase advances 30 degrees more than normal and the current phase of the V phase lags 30 degrees more than normal. After the fuse of the V phase blows, the current is controlled so that the current phase of the U phase advances 30 degrees more than normal and the current phase of the W phase lags 30 degrees more than normal. After the fuse of the W phase blows, the current is controlled so that the current phase of the V phase advances 30 degrees more than normal and the current phase of the U phase lags 30 degrees more than normal. The post-fuse blowing current control unit 312 calculates the duty values 312a of each phase and the motor neutral point so that the current phases of the remaining two phases become the values shown in FIG. 12.

[0103] FIG. 13 is a diagram showing examples of current waveforms and motor output torque waveforms after fuse blowing. (a) shows the waveforms of current and torque in normal operation, (b) shows the waveforms of current and torque when the currents of the V-phase and W-phase are controlled with the same current phase as in normal operation after the fuse in the U-phase blows, and (c) shows the waveforms of current and torque when the current phases of the V-phase and W-phase are controlled as shown in FIG. 12 after the fuse in the U-phase blows. In all of (a), (b), and (c), the uppermost graph represents the current waveforms of the U-phase / V-phase / W-phase. The middle graph represents the waveforms of the d-axis current and q-axis current. The lowermost graph represents the waveform of the output torque of the motor 190.

[0104] As shown in FIG. 13(a), in normal operation, the currents of each phase are controlled while maintaining a current phase difference of 120 degrees from each other, and both the d-axis current and the q-axis current at this time become constant values. Therefore, the output torque also maintains a constant value.

[0105] As shown in FIG. 13(b), when the current phases of the V-phase and W-phase are set to the same values as normal after the fuse in the U-phase blows, the d-axis current and the q-axis current increase and decrease oscillatingly in response to the change in the electrical angle. Therefore, the output torque also increases and decreases oscillatingly in response to the change in the electrical angle, and torque ripple occurs.

[0106] As shown in FIG. 13(c), when the current phase difference between the V-phase and W-phase is controlled to be 60 degrees after the fuse in the U-phase blows, although the values of the d-axis current and the q-axis current become 1 / √3 of those in normal operation, they can maintain a constant value regardless of the change in the electrical angle. Therefore, the output torque at this time becomes approximately 1 / √3 of that in normal operation, but it can maintain a constant value regardless of the change in the electrical angle, and the occurrence of torque ripple as shown in FIG. 13(b) can be suppressed.

[0107] In addition, in the example of FIG. 13(c), if the current amplitudes of the V-phase and W-phase are set to √3 times those in normal operation, the values of the d-axis current and the q-axis current at that time can be made the same as those in normal operation, and the output torque can also be made the same as that in normal operation.

[0108] Figure 14 is an example of a control flowchart in this embodiment. In this embodiment, the control circuit 10 shown in FIG. 8 periodically performs the control of FIG. 14 at regular intervals. In FIG. 14, the same symbols as those in the control flowchart of FIG. 7 described in the first embodiment are marked for the parts performing the same processing as in FIG. 7, and the description of those processes is omitted.

[0109] In this embodiment, in the process of step S104, if the internal state 19a is in the "short-circuit fault state of the power semiconductor element", the process proceeds to step S200; otherwise, the process proceeds to step S201.

[0110] In the process of step S200, the control circuit 10 performs fuse blowing control. More specifically, as described above, the target current calculation unit 142 for fuse blowing generates the target current values 142a for each phase and the neutral point based on the short-circuit fault location information 17a, and the current control unit 152 for fuse blowing generates the duty values 152a for each phase and the neutral point corresponding to the target current values 142a. Then, the PWM signal generation unit 162 generates a PWM signal 162a based on the duty values 152a for each phase and the neutral point, and outputs the PWM signal 162a to the driver circuit 20. As a result, the driving of the other power semiconductor elements 32 is controlled so that the current flowing through the power semiconductor element 32 determined as the short-circuit fault location in the short-circuit fault location determination unit 17 becomes equal to or greater than the fuse rated current.

[0111] In the process of step S201, the control circuit 10 determines that the fuse 60 of the faulty phase has blown and performs current control after the fuse has blown. Specifically, as described above, current control is implemented while changing the current phase of each phase other than the faulty phase. That is, the duty values 312a of each phase and the motor neutral point are calculated by the post-fuse current control unit 312 so that the current phase difference between the remaining two phases excluding the faulty phase becomes 60 degrees. Based on this duty value 312a, the PWM signal generation unit 162 generates a PWM signal 162a and outputs it to the driver circuit 20, thereby controlling the on / off of the power semiconductor elements 32 of the remaining two phases and the power semiconductor elements 32 for driving the motor neutral point voltage respectively.

[0112] As described above, in this embodiment, by controlling the neutral point current to be in the opposite direction to the current of the faulty phase, the absolute value of the current of the faulty phase can be increased. Since the fuse blowing time of the fuse 60 becomes shorter as the current value flowing through the fuse 60 increases, the fuse 60 at the faulty location can be blown earlier by controlling the neutral point current as described above. Also, as in this embodiment, by controlling the current phase difference between the remaining two phases to be 60 degrees after the fuse has blown, torque control with suppressed torque ripple can be continued even after the fuse has blown.

[0113] In the vehicle 1 of FIG. 1, when independent drive devices 200 are provided for the front and rear wheels respectively, as described in Embodiment 1, even if the operation of one drive device 200 fails and is stopped, the remaining drive device 200 can continue to drive the vehicle 1. However, when the drive device 200 is provided only on either the front or rear wheel, if the operation of the drive device 200 is stopped due to a failure, the vehicle 1 cannot continue to be driven.

[0114] On the one hand, by using the method of this embodiment, even when the vehicle 1 is provided with the drive device 200 only on one of the front and rear wheels, it becomes possible to continue driving the vehicle 1 after a short-circuit failure of the power semiconductor element. Therefore, there is no need to redundantize the drive device 200 for the purpose of continuing vehicle driving after a failure, and a vehicle 1 that can continue operation even after a failure can be realized at low cost.

Embodiment

[0115] In the fuse blowing control of the first and second embodiments, current control was performed so that a certain current flowed through the faulty phase. At this time, the torque output from the motor 190 becomes a state where the driving torque and the regenerative torque are periodically repeated, and the vehicle 1 may vibrate. In this state, since the ride comfort of the driver deteriorates, it is desirable to blow the fuse 60 at the faulty location in a shorter time and switch to control with less torque ripple.

[0116] In this embodiment, in view of the above problems, an example of the power conversion device 100 and the drive device 200 that can blow the fuse 60 at the faulty location in a shorter time when a short-circuit failure of the power semiconductor element occurs and can continue driving the motor 190 even after the fuse is blown is shown.

[0117] FIG. 15 is a diagram showing a configuration example of the power conversion device 100 and the drive device 200 in this embodiment. The control circuit 10 in the power conversion device 100 in this embodiment has a fuse blowing current control unit 153 and a fuse blowing determination unit 183 that are different from the fuse blowing current control unit 152 and the fuse blowing determination unit 18 at the time of fuse blowing in the second embodiment. Explanation of the components common to the first and second embodiments is omitted.

[0118] The fuse blowing current control unit 153 of this embodiment calculates the duty ratio of each phase in the same manner as the fuse blowing current control unit 152 of Embodiment 2. At this time, in the fuse blowing current control unit 15 of Embodiment 1 and the fuse blowing current control unit 152 of Embodiment 2, current control was performed by turning off the power semiconductor elements 32 of the upper and lower opposite arms in the same phase as the short-circuited power semiconductor element 32. However, in this embodiment, current control is performed by turning on the power semiconductor elements 32 of the upper and lower opposite arms in the same phase as the short-circuited power semiconductor element 32. As a result, in the upper and lower arm circuits of the faulty phase, the power semiconductor element 32 of one arm has a short-circuit fault, and the power semiconductor element of the other arm is in the on state. That is, the upper and lower arm circuits of the faulty phase are in the same state as when both the power semiconductor elements 32 of the upper and lower arms are turned on. Therefore, the voltage output from the power conversion circuit 302 to the winding of the faulty phase of the motor 190 becomes 0 [V]. In this embodiment, when converting from the α-axis target voltage value (Vα) and the β-axis target voltage value (Vβ) to the U-phase target voltage value (Vu), the V-phase target voltage value (Vv), and the W-phase target voltage value (Vw), and when calculating the neutral point target voltage value (Vn) from these target voltage values (Vu, Vv, Vw), the calculation is performed with this in mind.

[0119] FIG. 16 is a diagram showing an example in which fuse blowing control is performed when the power semiconductor element 32 of the U-phase upper arm has a short-circuit fault in this embodiment.

[0120] In this embodiment, as described above, the power semiconductor elements 32 (the power semiconductor elements 32 of the upper arm of the U phase) of the same phase as the short-circuited power semiconductor element 32 and the power semiconductor elements 32 of the upper and lower opposite arms (the power semiconductor elements 32 of the lower arm of the U phase) are turned on, and the on / off states of the power semiconductor elements 32 of the remaining V phase, W phase, and neutral point are controlled so that the currents flowing through these respective phases and the neutral point become the target currents. At this time, the fuse 60 (upper arm fuse) corresponding to the power semiconductor element 32 of the upper arm of the U phase is applied with both the through current flowing through the power semiconductor elements 32 of the upper and lower arms of the U phase and the phase current of the U phase. Therefore, a larger current can be applied to the fuse 60 compared to the case where only the phase current is simply applied to the fuse 60 as in the first and second embodiments. Therefore, the fuse 60 at the fault location can be blown in a shorter time. When the fuse 60 at the fault location is blown by the through current, the normal power semiconductor element 32 (the power semiconductor element 32 of the lower arm of the U phase) that is not short-circuited may be always kept in the on state, or PWM control that repeats on / off according to a predetermined duty may be performed on the power semiconductor element 32.

[0121] In addition, in the first and second embodiments, after the fuse is blown, almost no current flows through the winding of the faulty phase of the motor 190. However, in this embodiment, since the power semiconductor element of the upper and lower opposite arm to the short-circuited power semiconductor element 32 is turned on, current flows through the winding of the faulty phase even after the fuse is blown. Therefore, the blowing of the fuse 60 is determined by a method different from that of the first and second embodiments.

[0122] FIG. 17 is a diagram showing the state after the fuse has blown in this embodiment. FIG. 17 shows the state after the upper arm fuse corresponding to the power semiconductor element 32 of the U-phase upper arm that short-circuited in the example of FIG. 16 has blown. In this case, since the power semiconductor element 32 of the U-phase lower arm is in the on state, the voltage output from the upper and lower arm circuits of the U-phase to the winding of the motor 190 becomes -1 / 2Vdc. In this state, when the voltage of the neutral point 191 is on average higher than the U-phase output voltage, a negative current is generated in the U-phase. Also, when the voltage of the neutral point 191 is on average equal to the U-phase output voltage, positive and negative sine-wave-shaped currents flow in the U-phase due to the back electromotive force generated in the winding of the motor 190. Note that in the state of FIG. 17, the output voltage of the U-phase is always -1 / 2Vdc, and since it is physically impossible to make the applied voltage of the neutral point 191 lower than -1 / 2Vdc, the voltage of the neutral point 191 does not fall below the U-phase output voltage.

[0123] As described above, when the power semiconductor element 32 of the U-phase upper arm short-circuits, before the upper arm fuse corresponding to this power semiconductor element 32 blows, the phase current flowing in the U-phase was in the plus state, but after the upper arm fuse blows, it changes to the minus state or a sine-wave-shaped plus-minus current. Therefore, when the phase current flowing in the faulty phase is smoothed, and if the direction of the smoothed current is in the opposite direction to the target current for a certain period of time or more, or if the amplitude of the smoothed current remains below the threshold value for a certain period of time or more, it can be determined that the fuse at the faulty location has blown.

[0124] FIG. 18 is an example of a control flowchart in this embodiment. In this embodiment, the control circuit 10 shown in FIG. 15 periodically performs the control of FIG. 18 at regular intervals. In FIG. 18, the same symbols as those in the control flowchart of FIG. 14 described in Embodiment 2 are marked for the parts that perform the same processing, and the description of those processes is omitted.

[0125] In this embodiment, in the process of step S104, if the internal state 19a is the "short-circuit fault state of the power semiconductor device", the process proceeds to step S300; otherwise, the process proceeds to step S201.

[0126] In the process of step S300, the control circuit 10 performs fuse blowing control. More specifically, as described in Embodiment 2, the target current calculation unit 142 for fuse blowing generates the target current values 142a for each phase and the neutral point based on the short-circuit fault location information 17a. Then, as described above, the current control unit 153 for fuse blowing generates the duty values 153a for each phase and the neutral point corresponding to this target current 142a, and generates the duty values 153a so that the power semiconductor devices 32 of the upper and lower opposite arms in the same phase as the short-circuited power semiconductor device 32 are in the on state. The PWM signal generation unit 162 generates a PWM signal 162a based on the duty values 153a of each phase and the neutral point, and outputs the PWM signal 162a to the driver circuit 20. As a result, a through current and a phase current flow through the power semiconductor device 32 determined as the short-circuit fault location in the short-circuit fault location determination unit 17, and the driving of the other power semiconductor devices 32 is controlled so that the sum of these currents is equal to or greater than the fuse rated current.

[0127] Next, in the process of step S301, the fuse blowing determination unit 183 determines whether or not the fuse 60 at the fault location has been detected using the current of the fault phase obtained by smoothing the AC current sensor value 50a with respect to the phase current of the fault phase. Here, as described above, when the direction of the smoothed current of the fault phase is opposite to the target current for a certain period of time or more, or when the amplitude of the smoothed current of the fault phase remains less than the threshold value for a certain period of time or more, it is determined that the fuse 60 at the fault location has blown. When the blowing of the fuse 60 is detected, after outputting the fuse blowing determination signal 183a, the process proceeds to step S107.

[0128] As described above, in this embodiment, during fuse blowing control, the power semiconductor elements 32 on the upper and lower opposite sides of the same phase as the short-circuited power semiconductor element 32 are turned on, and both the through-current and the phase current are applied to the fuse 60 at the fault location. As a result, the fuse 60 at the fault location can be blown in a shorter time than in the case of Embodiment 2. Further, after the fuse is blown, the driving of the motor 190 can be continued in the same manner as in Embodiment 2.

Embodiment

[0129] In the fuse blowing control of Embodiment 3, a through-current is applied to the fuse 60 at the fault location. However, since this through-current is also applied to the normal power semiconductor element 32 in the faulty phase, there is a risk that this power semiconductor element 32 may be heated and damaged by the through-current. In that case, if both fuses 60 corresponding to the upper and lower arms of the faulty phase are not blown, there is a risk that the driving of the motor 190 cannot be continued.

[0130] In this embodiment, in order to address the above situation, examples of a power conversion device 100 and a drive device 200 are shown that can blow both fuses 60 of the upper and lower arms of the faulty phase in a short time and continue to drive the motor 190 even after the fuses are blown.

[0131] FIG. 19 is a diagram showing a configuration example of the power conversion device 100 and the drive device 200 in this embodiment. The control circuit 10 in the power conversion device 100 in this embodiment has a fuse blowing target current calculation unit 144, a fuse blowing current control unit 154, a state determination unit 194, a fuse blowing determination unit 184, and a PWM signal generation unit 164, which are different from the fuse blowing target current calculation unit 142, the fuse blowing current control unit 153, the state determination unit 19, the fuse blowing determination unit 183, and the PWM signal generation unit 162 during fuse blowing in Embodiment 3. Description of the components common to Embodiments 1 to 3 is omitted.

[0132] In this embodiment, the state determination unit 194 determines the state of the power conversion device 100 as one of the following states: "normal state", "power semiconductor element short-circuit fault state", "state after upper fuse blown", "state after lower fuse blown", and "state after both fuses blown", based on the short-circuit fault location information 17a of the power semiconductor element 32 output by the short-circuit fault location determination unit 17 and the fuse blown determination signal 184a output by the fuse blown determination unit 184. Here, the fuse blown determination signal 184a output by the fuse blown determination unit 184 can distinguish between a signal indicating the blowing of the fuse 60 corresponding to the upper arm (upper arm fuse) among the fuses 60 provided in the upper and lower arm circuits of the faulty phase, a signal indicating the blowing of the fuse 60 corresponding to the lower arm (lower arm fuse), and a signal indicating the blowing of both fuses 60 corresponding to the upper and lower arms (upper arm fuse and lower arm fuse). Hereinafter, the fuse blown determination signal 184a indicating the blowing of the upper arm fuse is referred to as the "upper fuse blown signal", the fuse blown determination signal 184a indicating the blowing of the lower arm fuse is referred to as the "lower fuse blown signal", and the fuse blown determination signal 184a indicating the blowing of both the upper arm fuse and the lower arm fuse is referred to as the "both fuses blown signal". Then, the state determination unit 194 outputs the current state (194a) to the target current calculation unit 144 at the time of fuse blowing, the current control unit 154 at the time of fuse blowing, the PWM signal generation unit 164, and the fuse blown determination unit 184.

[0133] Figure 20 is a table showing the internal state determination of the state determination unit 194 in this embodiment. The state determination unit 194 determines the next state from the current state and the events that have occurred at regular intervals, and updates the next state as the current state. The initial state is the "normal state". First, when the state determination unit 194 receives the short-circuit fault location information 17a of the power semiconductor element 32 from the short-circuit fault location determination unit 17 while the current state is the "normal state", it changes the next state to the "power semiconductor element short-circuit fault state". Otherwise, the next state remains the "normal state".

[0134] Further, when the state determination unit 194 receives an upper fuse blow signal as a fuse blow determination signal 184a from the fuse blow determination unit 184 while the current state is the "power semiconductor element short - circuit fault state", it changes the next state to the "state after upper fuse blow". When the current state is the "power semiconductor element short - circuit fault state" and the fuse blow determination unit 184 receives a lower fuse blow signal as the fuse blow determination signal 184a, it changes the next state to the "state after lower fuse blow". Otherwise, the next state remains the "power semiconductor element short - circuit fault state".

[0135] When the state determination unit 194 receives a both - side fuse blow signal as the fuse blow determination signal 184a from the fuse blow determination unit 184 while the current state is the "state after upper fuse blow", it changes the next state to the "state after both - side fuse blow". Otherwise, the next state remains the "state after upper fuse blow".

[0136] When the state determination unit 194 receives a both - side fuse blow signal as the fuse blow determination signal 184a from the fuse blow determination unit 184 while the current state is the "state after lower fuse blow", it changes the next state to the "state after both - side fuse blow". Otherwise, the next state remains the "state after lower fuse blow".

[0137] When the current state of the state determination unit 194 is the "state after both - side fuse blow", the next state remains the "state after both - side fuse blow".

[0138] The PWM signal generation unit 164 of this embodiment switches the PWM signal 164a output to the driver circuit 20 according to the internal state 194a output from the state determination unit 194. When the internal state 194a is in the "normal state", the PWM signal generation unit 164 generates the PWM signal 164a using the timer value and the duty value 13a of each phase output by the torque control current control unit 13, and outputs it to the driver circuit 20. When the internal state 194a is any one of the "power semiconductor element short-circuit fault state", the "state after upper fuse blown", and the "state after lower fuse blown", the PWM signal generation unit 164 uses the timer value and the duty value 154a of each phase and the motor neutral point output by the current control unit 154 at the time of fuse blowing to generate the PWM signal 164a, and outputs it to the driver circuit 20. When the internal state 194a is in the "state after both fuses blown", the PWM signal generation unit 164 uses the timer value and the duty value 312a of each phase and the motor neutral point output by the current control unit 312 after fuse blowing to generate the PWM signal 164a, and outputs it to the driver circuit 20.

[0139] Next, the current control during fuse blowing control in this embodiment will be described. The fuse blowing control of this embodiment is performed in two stages.

[0140] First, when the internal state 194a output from the state determination unit 194 is in the "short-circuit fault state of the power semiconductor element", the first-stage fuse blowing control is performed. At this time, the target current calculation unit 144 for fuse blowing sets the target current values 144a of each phase and the neutral point to 0 [A]. Then, the current control unit 154 for fuse blowing generates a duty value 154a for the faulty phase so that the power semiconductor elements 32 of the upper and lower opposite arms in the same phase as the short-circuited power semiconductor element 32 are turned on. As a result, the power semiconductor elements 32 of both the upper and lower arms of the faulty phase are turned on, a through current is passed through both of the fuses 60 corresponding to these power semiconductor elements 32, and one of the fuses 60 of either the upper or lower arm of the faulty phase is blown by this through current. For the other two phases and the neutral point, the duty value 154a is generated according to the target current value 144a (0 [A] for each phase) output by the target current calculation unit 144 for fuse blowing. This is equivalent to controlling the output voltages of the normal two phases and the neutral point so as to cancel the induced voltage (counter electromotive force) generated in the motor windings of each phase.

[0141] Note that at this time, similar to the fuse blowing control of the third embodiment, the current control unit 154 for fuse blowing needs to calculate the duty values 154a of the other two phases and the neutral point, taking into account that the voltage output from the power conversion circuit 302 to the winding of the faulty phase of the motor 190 becomes 0 [V]. Also, when the motor speed is low, if the power semiconductor elements 32 of the other two phases and the neutral point are turned off for both the upper and lower arms, the current flowing through each phase can be set to 0 [A], so such a duty value 154a may be generated. In this way, during the fuse blowing control by the through current, by controlling so that the phase current of each phase does not flow, it becomes easier to perform the fuse blowing determination described later, and there is also an effect that the heat generation of the power semiconductor of the normal phase during the fuse blowing control can be suppressed.

[0142] When the internal state 194a output from the state determination unit 194 is the "upper fuse blown state" or the "lower fuse blown state", the second-stage fuse blowing control is performed. In this state, since one of the fuses 60 in either the upper or lower arm of the faulty phase has been blown by the first-stage fuse blowing control, the remaining fuse 60 cannot be blown using the through current. Therefore, in the second-stage fuse blowing control, similar to the second embodiment, the phase current of the faulty phase is controlled to blow the remaining fuse 60. At this time, the target current calculation unit 144 for fuse blowing determines the target current values 144a of each phase and the neutral point in the same manner as in the second embodiment. Then, the current control unit 154 for fuse blowing generates a duty value 154a for the faulty phase so that the power semiconductor elements 32 in the upper and lower reverse arms in the same phase as the short-circuited power semiconductor element 32 are turned on. For the other two phases and the neutral point, the duty value 154a is generated according to the target current value 144a output by the target current calculation unit 144 for fuse blowing.

[0143] Note that when the internal state 194a is the "upper fuse blown state" at this time, in the upper and lower arm circuits of the faulty phase, the upper arm fuse is blown and only the power semiconductor element 32 on the lower arm side is in the on state. Therefore, the output voltage is -1 / 2Vdc. On the other hand, when the internal state 194a is the "lower fuse blown state", in the upper and lower arm circuits of the faulty phase, the lower arm fuse is blown and only the power semiconductor element 32 on the upper arm side is in the on state. Therefore, the output voltage is 1 / 2Vdc. The current control unit 154 for fuse blowing needs to calculate the duty values 154a of the other two phases and the neutral point taking this into account.

[0144] Subsequently, the fuse blowing determination in this embodiment will be described. The fuse blowing determination unit 184 in this embodiment performs the fuse blowing determination in two stages according to the fuse blowing control performed in two stages as described above.

[0145] First, the fuse blow judgment during the fuse blow control by the through current will be described. This fuse blow judgment is performed when one of the power semiconductor elements 32 in the upper and lower arms is in a short-circuit failure state and the other power semiconductor element 32 is in the on state in any one of the phases. That is, this fuse blow judgment is performed when the internal state 194a output from the state judgment unit 194 is in the "power semiconductor element short-circuit failure state" and the first-stage fuse blow control is being implemented. In this state, when neither of the fuses 60 in the upper and lower arms is blown, since the target current value 144a of each phase is 0 [A], the phase current of the faulty phase is controlled to be approximately 0 [A].

[0146] After the upper arm fuse is blown by the through current, as described above, the output voltage of the faulty phase becomes -1 / 2 Vdc, so a negative current flows through the faulty phase. Also, after the lower arm fuse is blown, the output voltage of the faulty phase becomes 1 / 2 Vdc, so a positive current flows through the faulty phase. Therefore, when the smoothed current value of the phase current flowing through the faulty phase is a positive value and this state where the magnitude of the current value is equal to or greater than a predetermined threshold is maintained for a predetermined time or more, the fuse blow judgment unit 184 determines that the lower arm fuse of the faulty phase has blown and outputs a lower side fuse blow signal to the state judgment unit 194. Also, when the smoothed current value of the phase current flowing through the faulty phase is a negative value and this state where the magnitude of the current value is equal to or greater than a predetermined threshold is maintained for a predetermined time or more, the fuse blow judgment unit 184 determines that the upper arm fuse of the faulty phase has blown and outputs an upper side fuse blow signal to the state judgment unit 194.

[0147] Next, the fuse blow determination during fuse blow control by the phase current will be described. This fuse blow determination is performed after either the upper or lower arm fuse 60 of the faulty phase has blown. That is, this fuse blow determination is performed when the internal state 194a output from the state determination unit 194 is the "state after upper fuse blow" or the "state after lower fuse blow", and when the second-stage fuse blow control is being carried out. In this state, if either the upper or lower arm fuse 60 of the faulty phase has not blown, a current equal to the target current value 144a set by the target current calculation unit 144 for fuse blow flows through the faulty phase.

[0148] When both the upper and lower arm fuses 60 of the faulty phase have blown, no current flows through the faulty phase. Therefore, when the state where the absolute value of the current in the faulty phase is below the threshold is maintained for a certain period or more, the fuse blow determination unit 184 determines that the remaining fuse 60 of the faulty phase has blown, and outputs a both-side fuse blow signal to the state determination unit 194.

[0149] FIG. 21 and FIG. 22 are examples of control flowcharts in this embodiment. In this embodiment, the control circuit 10 shown in FIG. 19 periodically performs the control of FIGS. 21 and 22 at regular intervals. In FIGS. 21 and 22, the same symbols as those in the control flowchart of FIG. 14 described in the second embodiment are used for the parts performing the same processing, and the description of those processes is omitted.

[0150] In this embodiment, in the process of step S104, if the internal state 194a is the "power semiconductor element short-circuit fault state", the process proceeds to step S400, and if it is other than the "power semiconductor element short-circuit fault state", the process proceeds to step S410.

[0151] In the process of step S400, the control circuit 10 performs fuse blowing control by means of through-current. More specifically, as described above, when the fuse blows, the target current calculation unit 144 sets the target current values 142a of each phase and the neutral point to 0 [A] based on the short-circuit fault location information 17a and the internal state 194a. Then, the current control unit 154 for fuse blowing generates the duty values 154a of each phase and the neutral point corresponding to this target current 144a, and generates the duty values 154a so that the power semiconductor elements 32 of the upper and lower opposite arms in the same phase as the short-circuited power semiconductor element 32 are in the on state. The PWM signal generation unit 164 generates a PWM signal 164a based on the duty values 154a of each phase and the neutral point, and outputs the PWM signal 164a to the driver circuit 20. As a result, a through-current flows through the power semiconductor element 32 determined as the short-circuit fault location in the short-circuit fault location determination unit 17 and the power semiconductor element 32 of the upper and lower opposite arms in the same phase as the power semiconductor element 32, and the driving of each power semiconductor element 32 of the fault phase is controlled so that this through-current becomes equal to or greater than the fuse rated current.

[0152] Next, in the process of step S401, the fuse blowing determination unit 184 performs a fuse blowing determination during fuse blowing control by means of through-current using the current of the fault phase obtained by smoothing the AC current sensor value 50a with respect to the phase current of the fault phase, and determines whether or not the fuse 60 on the upper arm side of the fault phase has blown. More specifically, as described above, when the smoothed current value of the fault phase is a negative value and the magnitude of the current value maintains a state equal to or greater than a predetermined threshold for a predetermined time or more, it is determined that the upper arm fuse of the fault phase has blown. When the blowing of the upper arm fuse is detected, after outputting an upper fuse blowing signal, the process proceeds to step S402. When the blowing of the fuse 60 on the upper arm side has not been detected, the process proceeds to the process of step S403.

[0153] In the process of step S402, the state determination unit 194 determines that the current state of the power conversion device 100 is the "state after upper fuse blown", and updates the internal state 194a. After executing the process of step S402, the control circuit 10 ends the control flowcharts of FIGS. 21 and 22.

[0154] In the process of step S403, the fuse blow determination unit 184 performs a fuse blow determination during fuse blow control by through current using the current of the faulty phase obtained by smoothing the AC current sensor value 50a with respect to the phase current of the faulty phase, and determines whether or not the fuse 60 on the lower arm side of the faulty phase has blown. More specifically, as described above, when the smoothed current value of the faulty phase is a positive value and this state where the magnitude of the current value is equal to or greater than a predetermined threshold is maintained for a predetermined time or more, it is determined that the lower arm fuse of the faulty phase has blown. If it is detected that the fuse 60 on the lower arm side has blown, after outputting a lower fuse blow signal, the process proceeds to step S404.

[0155] In the process of step S404, the state determination unit 194 determines that the current state of the power conversion device 100 is the "state after lower fuse blown", and updates the internal state 194a. After executing the process of step S404, the control circuit 10 ends the control flowcharts of FIGS. 21 and 22.

[0156] On the other hand, if it is not detected that the fuse 60 on the lower arm side has blown, the control circuit 10 does not execute the process of step S404 and ends the control flowcharts of FIGS. 21 and 22. In this case, the fuse blow determination unit 184 does not output a fuse blow determination signal 184a, and the state determination unit 194 maintains the internal state 194a as the "short circuit fault state of the power semiconductor element".

[0157] When it is determined in step S104 that the internal state 194a output from the state determination unit 194 is not in the "short-circuit fault state of the power semiconductor device", that is, when the internal state 194a is any of the "state after upper fuse blown", "state after lower fuse blown", and "state after both fuses blown", the control circuit 10 performs the one-sided fuse blown control shown in FIG. 22 in step S410.

[0158] In the one-sided fuse blown control of FIG. 22, first, in the process of step S411, the control circuit 10 determines whether the internal state 194a output from the state determination unit 194 is in the "state after upper fuse blown" or the "state after lower fuse blown". If the internal state 194a is either the "state after upper fuse blown" or the "state after lower fuse blown", it proceeds to step S412. If neither is the case, that is, if the internal state 194a is in the "state after both fuses blown", it proceeds to step S201.

[0159] In the process of step S412, the control circuit 10 performs fuse blown control based on the phase current. More specifically, similar to the second embodiment, the fuse blown target current calculation unit 144 generates the target current values 144a of each phase and the neutral point based on the short-circuit fault location information 17a. Then, the fuse blown current control unit 154 generates the duty values 154a of each phase and the neutral point corresponding to this target current 144a, and generates the duty values 154a so that the power semiconductor devices 32 of the upper and lower reverse arms in the same phase as the short-circuited power semiconductor device 32 are in the on state. The PWM signal generation unit 164 generates the PWM signal 164a based on the duty values 154a of each phase and the neutral point, and outputs the PWM signal 164a to the driver circuit 20. Thereby, the driving of the other power semiconductor devices 32 is controlled so that the phase current flowing through the fuse 60 detected as blown in step S401 or S403 and the fuses 60 of the upper and lower reverse arms in the fault phase becomes equal to or greater than the fuse rated current.

[0160] Next, in the process of step S413, the fuse blow determination unit 184 performs fuse blow determination during fuse blow control by the phase current using the current of the faulty phase obtained from the AC current sensor value 50a with respect to the phase current of the faulty phase, and determines whether the remaining fuses 60 of the faulty phase have been detected as blown. More specifically, as described above, when the state where the absolute value of the current value of the faulty phase is equal to or less than a predetermined threshold is maintained for a certain period of time or more, it is determined that the remaining fuses 60 have blown. When the blowing of the remaining fuses 60 of the faulty phase is detected, after outputting a bilateral fuse blow signal, the process proceeds to step S414.

[0161] In the process of step S414, the state determination unit 194 determines that the current state of the power conversion device 100 is the "state after bilateral fuse blow", and updates the internal state 194a. After executing the process of step S414, the control circuit 10 ends the control flowcharts of FIGS. 21 and 22.

[0162] On the other hand, when the blowing of the remaining fuses 60 of the faulty phase is not detected, the control circuit 10 does not execute the process of step S414 and ends the control flowcharts of FIGS. 21 and 22. In this case, the fuse blow determination unit 184 does not output a fuse blow determination signal 184a, and the state determination unit 194 maintains the internal state 194a as the "state after upper fuse blow" or the "state after lower fuse blow".

[0163] As described above, in this embodiment, during fuse blow control, first, the upper and lower opposite power semiconductor elements 32 of the same phase as the short-circuited power semiconductor element 32 are turned on, and the fuses 60 in either the upper or lower arm of the faulty phase are blown by the through current. Then, by flowing a current through the faulty phase and blowing the remaining fuses 60 by the phase current, both fuses 60 in the upper and lower arms of the faulty phase can be blown. Further, after the fuses are blown, the driving of the motor 190 can be continued in the same manner as in the second embodiment.

[0164] Furthermore, in the control method of this embodiment, when the fuse 60 of either the upper or lower arm of the faulty phase is blown by the through-current, the remaining fuse 60 of the faulty phase is also heated by the through-current and is in a state where it can be blown by applying a small phase current. Therefore, the time required to perform the fuse blowing control by the phase current is shorter than that in Embodiment 2, and the heat generation of each power semiconductor element 32 of the normal phase due to the fuse blowing control can be suppressed. In other words, in the control method of Embodiment 2, when the power semiconductor element 32 of the normal phase is at a high temperature, the target current at the time of fuse blowing must be suppressed and controlled, and it takes time to blow the fuse 60. On the other hand, in the control method of this embodiment, even when the power semiconductor element 32 of the normal phase is at a high temperature, the driving time of the power semiconductor element 32 of the normal phase is short, so a large current can flow. Therefore, compared with Embodiment 2, the fuse 60 of the faulty phase can be blown in a short time.

Embodiment

[0165] In this embodiment, examples of the power conversion device 100 and the drive device 200 that are lower in cost and smaller in size and can continue to drive the motor 190 even after a short-circuit fault of the power semiconductor element 32 are shown.

[0166] FIG. 23 is a diagram showing a configuration example of the power conversion device 100 and the drive device 200 in this embodiment. The power conversion device 100 in this embodiment has a power conversion circuit 305 with a configuration different from that of the power conversion circuit 302 in Embodiment 2. For the components common to Embodiments 1 to 4, the description will be omitted.

[0167] FIG. 24 is a diagram showing a configuration example of the power conversion circuit 305 and the motor 190 in this embodiment. Similar to the power conversion circuit 302 of the second embodiment, the power conversion circuit 305 of this embodiment has upper and lower arm circuits for driving the motor neutral point voltage connected to the neutral point 191 of the motor 190 in addition to the upper and lower arm circuits of each layer. Further, different from the power conversion circuit 302 of the second embodiment, the power conversion circuit 305 of this embodiment is provided with triple fuses 61 instead of the fuses 60 in the upper and lower arm circuits for each phase and the motor neutral point voltage drive. These triple fuses 61 are respectively connected to the power semiconductor element 32 of the upper arm, the power semiconductor element 32 of the lower arm, and the output line of the motor 190 in each upper and lower arm circuit.

[0168] In this embodiment, by configuring the power conversion circuit 305 as described above, the number of fuses provided in the second embodiment can be reduced to half, i.e., four. Therefore, while having the ability to drive the motor 190 even after a short-circuit failure of the power semiconductor element 32, the cost and size of the power conversion device 100 and the drive device 200 can be reduced.

[0169] As also described in the first embodiment, in this embodiment, a bus bar, a wire bonding, or the like that melts when a current equal to or greater than a certain value is applied may be used instead of the fuse.

[0170] Further, in this embodiment, an example of the power conversion circuit 305 in which the fuse 60 is replaced with the triple fuse 61 based on the second embodiment is described, but the triple fuse 61 of this embodiment can also be combined with the configuration of the power conversion circuit in other embodiments.

Embodiment

[0171] In this embodiment, examples of the power conversion device 100 and the drive device 200 are shown in which, when a short-circuit failure occurs in the power semiconductor element 32, the fuse 60 at the failure location melts with higher accuracy and in a shorter time, and the driving of the motor 190 can be continued even after the fuse melts.

[0172] FIG. 25 is a diagram showing a configuration example of the power conversion device 100 and the drive device 200 in the present embodiment. The control circuit 10 in the power conversion device 1000 in the present embodiment has an output voltage detection unit 326 in addition to each functional block in the second embodiment. Further, it has a fuse blowout current control unit 156 and a fuse blowout determination unit 186 that are different from the fuse blowout current control unit 152 and the fuse blowout determination unit 18 in the second embodiment. Description of the components common to the first to fifth embodiments will be omitted.

[0173] The output voltage detection unit 326 measures the voltage output from the power conversion circuit 302 to the windings of each phase of the motor 190, and outputs the voltage value 326a of each phase based on the measurement result to the fuse blowout current control unit 156 and the fuse blowout determination unit 186.

[0174] The fuse blowout current control unit 156 in the present embodiment basically performs the same control as the fuse blowout current control unit 152 in the second embodiment. However, in the second embodiment, the output voltage of the faulty phase was estimated from the location of the power semiconductor element 32 with a short-circuit fault, and the target voltage values of the two normal phases and the neutral point were calculated. In the present embodiment, the actual output voltage value 326a of the faulty phase output by the output voltage detection unit 326 is used to calculate the target voltage values of the two normal phases and the neutral point. As a result, the influence of voltage drop due to a bus bar or the like can be reflected in the target voltage value, and the current control at the time of fuse blowout can be performed with higher accuracy.

[0175] The fuse melting determination unit 186 in this embodiment determines whether the fuse 60 in the faulty phase has melted based on the output voltage value 326a of the faulty phase output by the output voltage detection unit 326 instead of the phase current. As described above, the output voltage of the phase in which the power semiconductor element 32 of either the upper arm or the lower arm has a short-circuit fault is 1 / 2Vdc before the fuse 60 melts when the power semiconductor element 32 of the upper arm has a short-circuit fault and the power semiconductor element 32 of the lower arm is in the off state, and -1 / 2Vdc when the power semiconductor element 32 of the lower arm has a short-circuit fault and the power semiconductor element 32 of the upper arm is in the off state. Also, when either one of the power semiconductor elements 32 of the upper and lower arms has a short-circuit fault and the other power semiconductor element 32 is in the on state, the value is near 1 / 2Vdc. On the other hand, when the fuse 60 corresponding to the short-circuited power semiconductor element 32 melts, the output voltage of the faulty phase changes according to the position of the fuse 60.

[0176] Therefore, the fuse melting determination unit 186 determines whether the fuse has melted by detecting the change in the output voltage of the faulty phase from the output voltage value 326a. For example, when the power semiconductor element 32 of the upper arm has a short-circuit fault and the power semiconductor element 32 of the lower arm is in the off state, if the output voltage of the faulty phase drops from 1 / 2Vdc to a certain threshold value or less, it can be determined that the upper arm fuse has melted. Similarly, when the power semiconductor element 32 of the lower arm has a short-circuit fault and the power semiconductor element 32 of the upper arm is in the off state, if the output voltage of the faulty phase rises from -1 / 2Vdc to a certain threshold value or more, it can be determined that the lower arm fuse has melted. Since these changes in the output voltage are steeper than the changes in the phase current, the fuse melting determination can be made in a shorter time, and the motor drive control can be continued in a shorter time.

[0177] As described above, in this embodiment, by using the output voltage value 326a of each phase output by the output voltage detection unit 326 for current control during fuse melting and fuse melting determination, the current control during fuse melting can be implemented with higher precision, and the fuse melting determination can be implemented in a shorter time.

[0178] Note that in this embodiment, based on Example 2, examples of the fuse blow current control unit 156 and the fuse blow determination unit 186 that perform current control during fuse blowing and fuse blow determination based on the output voltage value 326a output from the output voltage detection unit 326 are described. However, the output voltage detection unit 326, the fuse blow current control unit 156, and the fuse blow determination unit 186 of this embodiment can also be combined with other embodiments. In particular, when combined with Example 4 where the fuse blow determination is complex, the effect of shortening the fuse blow determination time can be made greater.

[0179] Specifically, in the fuse blow control by the through current performed in Example 4, when neither of the fuses 60 is blown, one of the power semiconductor elements 32 in either the upper or lower arm has a short circuit fault, and the other power semiconductor element 32 is in the on state. Therefore, the output voltage of the faulty phase detected by the output voltage detection unit 326 becomes a value near 0 [V]. On the other hand, when the upper arm fuse 60 is blown, the output voltage of the faulty phase becomes a value near -1 / 2 Vdc, and when the lower arm fuse 60 is blown, the output voltage of the faulty phase becomes a value near 1 / 2 Vdc. Therefore, in the control flowcharts of FIGS. 21 and 22 described in Example 4, in each of the processes of steps S401 and S403, by detecting these voltage changes in the output voltage of the faulty phase detected by the output voltage detection unit 326, the fuse blow determination can be performed. That is, in the process of step S403, the fuse blow determination unit 186 determines whether the voltage output from the power conversion circuit 302 to the winding of the faulty phase and detected by the output voltage detection unit 326 is equal to or greater than a predetermined threshold value set larger than 0 [V]. If it is equal to or greater than the threshold value, it can be determined that the lower arm fuse of the faulty phase has blown. Also, in the process of step S401, the fuse blow determination unit 186 determines whether the voltage output from the power conversion circuit 302 to the winding of the faulty phase and detected by the output voltage detection unit 326 is equal to or less than a predetermined threshold value set smaller than 0 [V]. If it is equal to or less than the threshold value, it can be determined that the upper arm fuse of the faulty phase has blown.

Example

[0180] In this embodiment, an example of a power conversion device 100 and a drive device 200 is shown, in which when a short-circuit fault occurs in the power semiconductor element 32, the fuse 60 at the fault location is blown by more optimal control, and the driving of the motor 190 can be continued even after the fuse is blown.

[0181] FIG. 26 is a diagram showing a configuration example of the power conversion device 100 and the drive device 200 in this embodiment. The control circuit 10 in the power conversion device 100 in this embodiment has a power semiconductor temperature calculation unit 337 in addition to each functional block of Embodiment 4. Further, the fuse blowing target current calculation unit 147, the fuse blowing current control unit 157, the state determination unit 197, the fuse blowing determination unit 187, and the PWM signal generation unit 167, which are different from the fuse blowing target current calculation unit 144, the fuse blowing current control unit 154, the state determination unit 194, the fuse blowing determination unit 184, and the PWM signal generation unit 164 in Embodiment 4, respectively. The description of the components common to Embodiments 1 to 6 is omitted.

[0182] The power semiconductor temperature calculation unit 337 measures the temperature of each power semiconductor element 32 in the power conversion circuit 302, and outputs a power semiconductor temperature 337a to the state determination unit 197 based on the measurement result.

[0183] In this embodiment, the state determination unit 197 determines the state of the power conversion device 100 as one of the states of "normal state", "fuse blowing control state due to through current", "state after upper fuse blowing", "state after lower fuse blowing", "fuse blowing control state due to phase current", and "state after both side fuses blowing" based on the short - circuit fault location information 17a of the power semiconductor element 32 output by the short - circuit fault location determination unit 17, the power semiconductor temperature 337a output by the power semiconductor temperature calculation unit 337, and the fuse blowing determination signal 187a output by the fuse blowing determination unit 187. Here, the fuse blowing determination signal 187a output by the fuse blowing determination unit 187 is, similar to the fuse blowing determination signal 184a in Embodiment 4, either an upper - side fuse blowing signal indicating the blowing of the upper - arm fuse, a lower - side fuse blowing signal indicating the blowing of the lower - arm fuse, or a both - side fuse blowing signal indicating the blowing of both the upper - arm fuse and the lower - arm fuse. And the state determination unit 197 outputs the current state (197a) to the fuse blowing target current calculation unit 147, the fuse blowing current control unit 157, the PWM signal generation unit 167, and the fuse blowing determination unit 187.

[0184] Figure 27 is a table showing the internal state determination of the state determination unit 197 in this embodiment. The state determination unit 197 determines the next state from the current state and the occurring events at regular intervals and updates the next state as the current state. The initial state is the "normal state". First, when the state determination unit 197 receives the short - circuit fault location information 17a of the power semiconductor element 32 from the short - circuit fault location determination unit 17 in the case where the current state is the "normal state", if the maximum temperature of the power semiconductor element 32 in the normal phase is equal to or higher than a predetermined threshold value, the next state is changed to the "fuse blowing control state due to through current". On the other hand, when receiving the short - circuit fault location information 17a of the power semiconductor element 32 from the short - circuit fault location determination unit 17, if the maximum temperature of the power semiconductor element 32 in the normal phase is less than the predetermined threshold value, the next state is changed to the "fuse blowing control state due to phase current". In other cases, the next state remains the "normal state".

[0185] Further, when the state determination unit 197 receives an upper fuse blow signal as a fuse blow determination signal 187a from the fuse blow determination unit 187 while the current state is the "control state after fuse blow due to through current", it changes the next state to the "state after upper fuse blow". When the state determination unit 197 receives a lower fuse blow signal as a fuse blow determination signal 187a from the fuse blow determination unit 187 while the current state is the "control state after fuse blow due to through current", it changes the next state to the "state after lower fuse blow". Otherwise, the next state remains the "control state after fuse blow due to through current".

[0186] When the state determination unit 197 receives a both - side fuse blow signal as a fuse blow determination signal 187a from the fuse blow determination unit 187 while the current state is the "state after upper fuse blow", it changes the next state to the "state after both - side fuse blow". Otherwise, the next state remains the "state after upper fuse blow".

[0187] When the state determination unit 197 receives a both - side fuse blow signal as a fuse blow determination signal 187a from the fuse blow determination unit 187 while the current state is the "state after lower fuse blow", it changes the next state to the "state after both - side fuse blow". Otherwise, the next state remains the "state after lower fuse blow".

[0188] When the state determination unit 197 receives a both - side fuse blow signal as a fuse blow determination signal 187a from the fuse blow determination unit 187 while the current state is the "fuse blow control state due to phase current", it changes the next state to the "state after both - side fuse blow". Otherwise, the next state remains the "fuse blow control state due to phase current".

[0189] When the current state of the state determination unit 197 is the "state after both - side fuse blow", the next state remains the "state after both - side fuse blow".

[0190] The PWM signal generation unit 167 of this embodiment switches the PWM signal 167a output to the driver circuit 20 according to the internal state 197a output from the state determination unit 197. When the internal state 197a is in the "normal state", the PWM signal generation unit 167 generates the PWM signal 167a using the timer value and the duty value 13a of each phase output by the torque control current control unit 13, and outputs it to the driver circuit 20. When the internal state 197a is any one of the "fuse blowing control state due to through current", "state after upper fuse blowing", and "state after lower fuse blowing", the PWM signal generation unit 167 uses the timer value and the duty value 157a of each phase and the motor neutral point output by the fuse blowing current control unit 157 to generate the PWM signal 167a, and outputs it to the driver circuit 20. When the internal state 197a is in the "state after both side fuse blowing", the PWM signal generation unit 167 uses the timer value and the duty value 312a of each phase and the motor neutral point output by the current control unit 312 after fuse blowing to generate the PWM signal 167a, and outputs it to the driver circuit 20.

[0191] Next, the current control during fuse blowing control in this embodiment will be described. The fuse blowing control of this embodiment is divided into the following two patterns.

[0192] When the internal state 197a output from the state determination unit 197 is in the "fuse blowing control state due to through current", current control is performed in the same manner as the first-stage fuse blowing control (fuse blowing control due to through current) in Embodiment 4.

[0193] On the other hand, when the internal state 197a output from the state determination unit 197 is any one of the "state after upper fuse blowing", "state after lower fuse blowing", and "fuse blowing control state due to phase current", current control is performed in the same manner as the second-stage fuse blowing control (fuse blowing control due to phase current) in Embodiment 4.

[0194] Next, the fuse blow determination in this embodiment will be described. The fuse blow determination unit 187 in this embodiment performs fuse blow determination in the following two types of methods according to the fuse blow control performed in two patterns as described above.

[0195] When the internal state 197a output from the state determination unit 197 is the "fuse blow control state by through current", the fuse blow determination is performed in the same method as the first-stage fuse blow determination (fuse blow determination during fuse blow control by through current) in Embodiment 4, and it is determined whether the fuse 60 on the upper arm side has blown or the fuse 60 on the lower arm side has blown.

[0196] When the internal state 197a output from the state determination unit 197 is any one of the "state after upper fuse blow", "state after lower fuse blow", and "fuse blow control state by phase current", the fuse blow determination is performed in the same method as the second-stage fuse blow determination (fuse blow determination during fuse blow control by phase current) in Embodiment 4.

[0197] FIG. 28 and FIG. 29 are examples of control flowcharts in this embodiment. In this embodiment, the control circuit 10 shown in FIG. 26 periodically performs the control of FIGS. 28 and 29 at regular intervals. In FIGS. 28 and 29, the same symbols as those in the control flowcharts of FIGS. 21 and 22 described in Embodiment 4 are marked for the parts performing the same processing, and the description of those processes is omitted.

[0198] In this embodiment, in the process of step S100, when the internal state 197a is the "normal state", the process proceeds to step S101, and when it is other than the "normal state", the process proceeds to step S703. Also, in the process of step S102, when a short-circuit fault is detected in any of the power semiconductor elements 32, the process proceeds to step 700.

[0199] In the process of step S700, the state determination unit 197 determines whether or not the maximum temperature of the power semiconductor element 32 in the normal phase is equal to or higher than a predetermined threshold value based on the short - circuit fault location information 17a output by the short - circuit fault location determination unit 17 and the power semiconductor temperature 337a output by the power semiconductor temperature calculation unit 337. When the maximum temperature is equal to or higher than the threshold value, in the process of step S701, the state determination unit 197 updates the internal state 197a to the "fuse - blowing control state by through - current". When the maximum temperature is less than the threshold value, in the process of step S702, the state determination unit 197 updates the internal state 197a to the "fuse - blowing control state by phase - current". After executing the process of step S701 or S702, the control circuit 10 ends the control flowcharts of FIGS. 28 and 29.

[0200] In the process of step S703, the control circuit 10 determines whether or not the internal state 197a is in the "fuse - blowing control state by through - current". When the internal state 197a is in the "fuse - blowing control state by through - current", the process proceeds to step S400; otherwise, the process proceeds to step S710.

[0201] In step S710, the control circuit 10 performs the phase - current fuse - blowing control shown in FIG. 29. In the phase - current fuse - blowing control of FIG. 29, in the process of step S711, the control circuit 10 determines whether or not the internal state 197a output from the state determination unit 197 is any one of the "upper - side fuse - blown state", "lower - side fuse - blown state", and "fuse - blowing control state by phase - current". When the internal state 197a corresponds to any of these states, the process proceeds to the process of step S412; when it does not correspond to any of the states, that is, when the internal state 197a is in the "both - side fuse - blown state", the process proceeds to the process of step S201.

[0202] As described above, in this embodiment, depending on whether the temperature of the normal-phase power semiconductor element 32 is equal to or higher than the threshold value, it is switched whether to perform fuse blowing control by the through current or to perform fuse blowing control by the phase current. As described in the effects of Embodiment 4, in the method of blowing the fuse 60 of either the upper or lower arm of the faulty phase by the fuse blowing control by the through current and then blowing the remaining fuse 60 of the faulty phase by the phase current, the time for the fuse blowing control by the phase current is short, and even if the temperature of the normal-phase power semiconductor element 32 is high, the fuse of the faulty phase can be blown in a short time. On the other hand, when performing the fuse blowing control by the through current, since both fuses 60 of the upper and lower arms of the faulty phase are blown, when the power semiconductor element 32 is at a low temperature, compared with the case of simply blowing the fuse 60 at the faulty location only by the phase current, there is a possibility that it may take a long time to blow the fuse 60. Therefore, as in this embodiment, when the normal-phase power semiconductor element 32 is at a high temperature, the fuses 60 of the upper and lower arms of the faulty phase are blown by combining the fuse blowing control by the through current and the fuse blowing control by the phase current, and when the normal-phase power semiconductor element 32 is at a low temperature, only the fuse 60 at the faulty location is blown by the fuse blowing control by the phase current, so that the fuse 60 can be blown in a shorter time.

[0203] According to each of the embodiments of the present invention described above, the following operational effects are achieved.

[0204] (1) The power conversion device 100 includes power conversion circuits 30, 302, 305 in which at least three-phase upper and lower arm circuits, each formed by connecting power semiconductor elements 32, which are switching elements, in series, are connected in parallel, a plurality of fuses 60, 61 connected in series with the power semiconductor elements 32 of each phase of the power conversion circuits 30, 302, 305 and melting when a current is equal to or greater than a predetermined rated current, a short-circuit fault location determination unit 17 for determining a short-circuit fault location of the power semiconductor element 32, and fuse blowing current control units 15, 152, 153, 154, 156, 157 for controlling the drive of other power semiconductor elements 32 different from the power semiconductor element 32 such that the current flowing through the power semiconductor element 32 determined to be the short-circuit fault location by the short-circuit fault location determination unit 17 becomes equal to or greater than the rated current of the fuses 60, 61. By doing so, when a short-circuit fault occurs in the power semiconductor element 32, which is a switching element, the fuses 60, 61 at the fault location can be surely blown.

[0205] (2) The fuse blowing current control unit 153 controls the power semiconductor element 32 of a different phase such that a current flows through the power semiconductor element 32 of the different phase via the winding of the motor 190, which is a load, and switches the power semiconductor element 32 connected in series with the power semiconductor element 32 determined to be the short-circuit fault location to the on state (step S300). By doing so, the fuse 60 at the fault location can be blown in a short time.

[0206] (3) The power conversion circuit 302 has a positive-side wiring connected to the positive electrode side of the DC power supply 210 and a negative-side wiring connected to the negative electrode side of the DC power supply 210. In the power conversion circuit 302, the upper and lower arm circuits of each phase are respectively connected between the positive-side wiring and the negative-side wiring, and output lines connected to the windings of each phase of the motor 190 are respectively connected between the power semiconductor element 32 of the upper arm and the power semiconductor element 32 of the lower arm. The plurality of fuses 60 include an upper-arm fuse connected in series with the power semiconductor element 32 of the upper arm between the positive-side wiring and the output line, and a lower-arm fuse connected in series with the power semiconductor element 32 of the lower arm between the negative-side wiring and the output line, in the upper and lower arm circuits of each phase. When a fuse blows, the current control unit 154 turns on the power semiconductor element 32 connected in series with the power semiconductor element 32 determined to be the short-circuit fault location in the faulty phase, with the phase to which the power semiconductor element 32 determined to be the short-circuit fault location belongs being the faulty phase (step S400). Also, after either the upper-arm fuse or the lower-arm fuse of the faulty phase blows (step S411: Yes), the driving of another power semiconductor element 32 different from the power semiconductor element 32 determined to be the short-circuit fault location is controlled so that the current flowing through the other one becomes equal to or greater than the rated current of the fuse 60 (step S412). By doing so, both the fuses 60 of the upper and lower arms of the faulty phase can be blown in a short time, and the driving of the motor 190 can be continued even after the fuses blow.

[0207] (4) The power conversion device 100 includes a fuse blow determination unit 184 that determines whether or not the fuse 60 has blown in the faulty phase. The fuse blow determination unit 184 determines that the lower-arm fuse of the faulty phase has blown when the current value obtained by smoothing the phase current flowing through the faulty phase is a positive value and the magnitude of the current value maintains a state equal to or greater than a predetermined threshold for a predetermined time or more (step S403). Also, the fuse blow determination unit 184 determines that the upper-arm fuse of the faulty phase has blown when the current value obtained by smoothing the phase current flowing through the faulty phase is a negative value and the magnitude of the current value maintains a state equal to or greater than the threshold for a predetermined time or more (step S401). By doing so, it is possible to surely determine which of the upper and lower arm fuses of the faulty phase has blown.

[0208] (5) The power conversion device 100 includes an output voltage detection unit 326 that measures the voltage output from the power conversion circuit 302 to the windings of each phase of the motor 190, and a fuse blow determination unit 186 that determines whether or not the fuse 60 has blown in the faulty phase. When the voltage output from the power conversion circuit 302 to the winding of the faulty phase is greater than or equal to a predetermined first threshold value, for example, a threshold value set greater than 0 [V], the fuse blow determination unit 186 can determine that the lower arm fuse of the faulty phase has blown (step S403). Also, when the voltage output from the power conversion circuit 302 to the winding of the faulty phase is less than or equal to a predetermined second threshold value smaller than the first threshold value, for example, a threshold value set smaller than 0 [V], the fuse blow determination unit 186 can determine that the upper arm fuse of the faulty phase has blown (step S401). In this way, it is possible to determine which of the upper and lower arm fuses of the faulty phase has blown in a shorter time.

[0209] (6) During the process of step S400, while the power semiconductor element 32 connected in series with the power semiconductor element 32 determined to be the short-circuit fault location is in the on state, the fuse blow current control unit 154 controls the driving of the other power semiconductor elements 32 so as to cancel out the induced voltage generated in the windings of each phase of the motor 190 except for the faulty phase according to the target current values 142a of each phase and the neutral point set to 0 [A]. By doing so, the heat generation of each power semiconductor element 32 in the normal phase can be suppressed and its temperature rise can be suppressed. Therefore, after one of the fuses 60 in the faulty phase has blown, it becomes possible to further increase the current that can flow through each phase, and the remaining fuse 60 in the faulty phase can be blown in an even shorter time.

[0210] (7) The power conversion circuit 302 has a positive-side wiring connected to the positive electrode side of the DC power supply 210 and a negative-side wiring connected to the negative electrode side of the DC power supply 210. The upper and lower arm circuits of each phase are respectively connected between the positive-side wiring and the negative-side wiring, and output lines connected to the windings of each phase of the motor 190 are respectively connected between the power semiconductor element 32 of the upper arm and the power semiconductor element 32 of the lower arm. The plurality of fuses 60 include an upper arm fuse connected in series with the power semiconductor element 32 of the upper arm between the positive-side wiring and the output line, and a lower arm fuse connected in series with the power semiconductor element 32 of the lower arm between the negative-side wiring and the output line in the upper and lower arm circuits of each phase. When the temperature of another power semiconductor element 32 different from the power semiconductor element 32 determined to be the short-circuit fault location is less than a predetermined threshold (step S700: No), the fuse blowing current control unit 157 sets the phase to which the power semiconductor element 32 determined to be the short-circuit fault location belongs as the fault phase, turns off the power semiconductor element 32 connected in series with the power semiconductor element 32 determined to be the short-circuit fault location in the fault phase, and controls the drive of the power semiconductor elements 32 of each phase excluding the fault phase so that the current flowing through the power semiconductor element 32 determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse 60 (step S702). Further, when the temperature of another power semiconductor element 32 different from the power semiconductor element 32 determined to be the short-circuit fault location is equal to or greater than the threshold (step S700: Yes), the power semiconductor element 32 connected in series with the power semiconductor element 32 determined to be the short-circuit fault location in the fault phase is turned on (step S701), and after either the upper arm fuse or the lower arm fuse of the fault phase is blown (step S711: Yes), the drive of another power semiconductor element 32 different from the power semiconductor element 32 determined to be the short-circuit fault location is controlled so that the current flowing through the other one becomes equal to or greater than the rated current of the fuse 60 (step S412). By doing so, the fuses 60 on both the upper and lower arms of the fault phase can be blown in an even shorter time, and the drive of the motor 190 can be continued even after the fuses are blown.

[0211] (8) The upper and lower arm circuits of each phase have output lines connected to the windings of each phase of the motor 190 respectively, between the power semiconductor element 32 of the upper arm and the power semiconductor element 32 of the lower arm. A plurality of fuses connected in series with the power semiconductor element 32 of each phase include a triple fuse 61 connected to the power semiconductor element 32 of the upper arm, the power semiconductor element 32 of the lower arm, and the output line respectively in the upper and lower arm circuits of each phase. By doing so, in the power conversion circuits 30, 302, 305, the number of fuses can be reduced, so that the cost reduction and miniaturization of the power conversion device 100 can be achieved.

[0212] The present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention as long as the features of the present invention are not impaired. Also, a part of the configuration of one embodiment may be replaced with the configuration of another embodiment, or the configuration of another embodiment may be added to the configuration of one embodiment.

Explanation of Reference Numerals

[0213] 1: Vehicle 2: Driving wheel 3: Non-driving wheel 4: Axle 10: Control circuit 11: Motor speed calculation unit 11a: Motor speed value 12: Target current calculation unit during torque control 12a: Target current value 13: Current control unit during torque control 13a: Duty value 14, 142, 144, 147: Target current calculation unit when fuse blows 14a, 142a, 144a, 147a: Target current value 15, 152, 153, 154, 156, 157: Current control unit when fuse blows 15a, 152a, 153a, 154a, 156a, 157a: Duty value 16, 162, 164, 167: PWM signal generation unit 16a, 162a, 164a, 167a: PWM signal 17: Short - circuit fault location determination unit 17a: Short - circuit fault location information 18, 183, 184, 186, 187: Fuse blowing determination unit 18a, 183a, 184a, 186a, 187a: Fuse blowing determination signal 19, 194, 197: State determination unit 19a, 194a, 197a: Internal state 20: Driver circuit 20a: Drive signal 20b: Short - circuit fault detection signal 30, 302, 305: Power conversion circuit 31: Smoothing capacitor 32: Power semiconductor device 33: Sense terminal 33a: Sense current 40: Voltage sensor 40a: Voltage sensor value 50: Alternating - current current sensor 50a: Alternating - current current sensor value 60: Fuse 61: Three - phase fuse 100: Power conversion device 190: Motor 191: Motor neutral point 200: Drive device 210: DC power supply 220: Abnormality notification device 312: Current control unit after fuse blowing 312a: Duty value 326: Output voltage detection unit 337: Power semiconductor temperature calculation unit

Claims

1. A power conversion circuit in which at least three upper and lower arm circuits with switching elements connected in series are connected in parallel, A plurality of fuses each connected in series with the switching elements of each phase of the power conversion circuit and melting at a predetermined rated current or more, A short-circuit fault location determination unit that determines the short-circuit fault location of the switching element, A current control unit at the time of fuse melting that controls the drive of other switching elements different from the switching element so that the current flowing through the switching element determined to be the short-circuit fault location by the short-circuit fault location determination unit is equal to or greater than the rated current of the fuse, The current control unit at the time of fuse melting controls the switching element of a different phase so that current flows through the switching element of a different phase than the switching element determined to be the short-circuit fault location via a load, and switches the switching element connected in series with the switching element determined to be the short-circuit fault location to the on state. A power conversion device.

2. The power conversion device according to claim 1, The power conversion circuit has a positive electrode side wiring connected to the positive electrode side of the DC power supply and a negative electrode side wiring connected to the negative electrode side of the DC power supply, The upper and lower arm circuits of each phase are respectively connected between the positive electrode side wiring and the negative electrode side wiring, and output lines connected to the windings of each phase of the motor are respectively connected between the switching element of the upper arm and the switching element of the lower arm, The plurality of fuses include an upper arm fuse connected in series with the switching element of the upper arm between the positive electrode side wiring and the output line, and a lower arm fuse connected in series with the switching element of the lower arm between the negative electrode side wiring and the output line in the upper and lower arm circuits of each phase, The current control unit at the time of fuse melting is, Taking the phase to which the switching element determined to be the short-circuit fault location belongs as the fault phase, turning on the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase, After either the upper arm fuse or the lower arm fuse in the fault phase is melted, the drive of other switching elements different from the switching element determined to be the short-circuit fault location is controlled so that the current flowing through the other one becomes equal to or greater than the rated current of the fuse. A power conversion device.

3. The power conversion device according to claim 2, A fuse melting determination unit that determines whether or not the fuse has melted in the faulty phase is provided. The fuse melting determination unit When the current value obtained by smoothing the phase current flowing through the faulty phase is a positive value and the state where the magnitude of the current value is equal to or greater than a predetermined threshold is maintained for a predetermined time or more, it is determined that the lower arm fuse of the faulty phase has melted. A power conversion device that determines that the upper arm fuse of the faulty phase has melted when the current value obtained by smoothing the phase current flowing through the faulty phase is a negative value and the state where the magnitude of the current value is equal to or greater than the threshold is maintained for the predetermined time or more.

4. The power conversion device according to claim 2, An output voltage detection unit that measures the voltage output from the power conversion circuit to the windings of each phase of the motor, A fuse melting determination unit that determines whether or not the fuse has melted in the faulty phase is provided. The fuse melting determination unit When the voltage output from the power conversion circuit to the winding of the faulty phase is equal to or greater than a predetermined first threshold, it is determined that the lower arm fuse of the faulty phase has melted. A power conversion device that determines that the upper arm fuse of the faulty phase has melted when the voltage output from the power conversion circuit to the winding of the faulty phase is equal to or less than a predetermined second threshold that is smaller than the first threshold.

5. The power conversion device according to claim 2, While the switching element connected in series with the switching element determined to be the short-circuit fault location by the fuse melting current control unit is in the on state, the fuse melting current control unit controls the driving of the other switching elements so as to cancel the induced voltage generated in the windings of each phase of the motor excluding the faulty phase. A power conversion device.

6. A power conversion circuit in which at least three upper and lower arm circuits in which switching elements are connected in series are connected in parallel, A plurality of fuses each connected in series with the switching elements of each phase of the power conversion circuit and melting at a predetermined rated current or more, A short-circuit fault location determination unit that determines the short-circuit fault location of the switching element, A fuse melting current control unit that controls the driving of another switching element different from the switching element so that the current flowing through the switching element determined to be the short-circuit fault location by the short-circuit fault location determination unit becomes equal to or greater than the rated current of the fuse. The power conversion circuit has a positive electrode side wiring connected to the positive electrode side of the DC power supply and a negative electrode side wiring connected to the negative electrode side of the DC power supply. The upper and lower arm circuits of each phase are respectively connected between the positive electrode side wiring and the negative electrode side wiring, and output lines connected to the windings of each phase of the motor are respectively connected between the switching element of the upper arm and the switching element of the lower arm. The plurality of fuses include an upper arm fuse connected in series with the switching element of the upper arm between the positive electrode side wiring and the output line, and a lower arm fuse connected in series with the switching element of the lower arm between the negative electrode side wiring and the output line in the upper and lower arm circuits of each phase. When the fuse blows, the current control unit When the temperature of another switching element different from the switching element determined to be the short-circuit fault location is less than a predetermined threshold value, the phase to which the switching element determined to be the short-circuit fault location belongs is set as the fault phase, and the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase is turned off. At the same time, the driving of the switching elements of each phase except the fault phase is controlled so that the current flowing through the switching element determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse. When the temperature of another switching element different from the switching element determined to be the short-circuit fault location is equal to or greater than the threshold value, the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase is turned on. After either the upper arm fuse or the lower arm fuse in the fault phase is blown, the driving of another switching element different from the switching element determined to be the short-circuit fault location is controlled so that the current flowing through the other one becomes equal to or greater than the rated current of the fuse. A power conversion device.

7. A power conversion device according to claim 1, The upper and lower arm circuits of each phase have output lines connected to the windings of each phase of the motor respectively between the switching element of the upper arm and the switching element of the lower arm. The plurality of fuses include a three-way fuse connected to the switching element of the upper arm, the switching element of the lower arm, and the output line respectively in the upper and lower arm circuits of each phase. A power conversion device.

8. A drive device including a power conversion device that outputs three-phase alternating current and a rotating electric machine driven by the three-phase alternating current, wherein the power conversion device includes: a power conversion circuit in which at least three-phase upper and lower arm circuits each having switching elements connected in series are connected in parallel; a plurality of fuses each connected in series with the switching element of each phase of the power conversion circuit and blowing when a current equal to or greater than a predetermined rated current flows; a short-circuit fault location determination unit that determines a short-circuit fault location of the switching element; a current control unit at the time of fuse blowing that controls driving of another switching element different from the switching element determined to be the short-circuit fault location by the short-circuit fault location determination unit so that the current flowing through the switching element determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse; The fuse blowing current control unit controls the switching element of a different phase so that a current flows through the switching element of a different phase via a load, and switches the switching element connected in series with the switching element determined to be the short-circuit fault location to an on state.

9. The drive device according to claim 8, wherein the power conversion circuit has a positive-side wiring connected to the positive electrode side of a DC power supply and a negative-side wiring connected to the negative electrode side of the DC power supply, each of the upper and lower arm circuits of each phase is connected between the positive-side wiring and the negative-side wiring, and output lines connected to windings of each phase of the rotating electric machine are respectively connected between the switching element of the upper arm and the switching element of the lower arm, the plurality of fuses include an upper arm fuse connected in series with the switching element of the upper arm between the positive-side wiring and the output line and a lower arm fuse connected in series with the switching element of the lower arm between the negative-side wiring and the output line in each of the upper and lower arm circuits of each phase, and the fuse blowing current control unit: sets the phase to which the switching element determined to be the short-circuit fault location belongs as a fault phase, and turns on the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase. After either the upper arm fuse or the lower arm fuse of the faulty phase is blown, a driving device that controls the driving of another switching element different from the switching element determined to be the short-circuit fault location so that the current flowing through the other one becomes equal to or greater than the rated current of the fuse.

10. The driving device according to claim 9, comprising a fuse blow determination unit that determines whether or not the fuse has blown in the faulty phase, wherein the fuse blow determination unit determines that the lower arm fuse of the faulty phase has blown when the current value obtained by smoothing the phase current flowing through the faulty phase is a positive value and the magnitude of the current value maintains a state equal to or greater than a predetermined threshold for a predetermined time or more, and determines that the upper arm fuse of the faulty phase has blown when the current value obtained by smoothing the phase current flowing through the faulty phase is a negative value and the magnitude of the current value maintains a state equal to or greater than the threshold for the predetermined time or more.

11. The driving device according to claim 9, comprising an output voltage detection unit that measures the voltage output from the power conversion circuit to the windings of each phase of the rotating electrical machine, and a fuse blow determination unit that determines whether or not the fuse has blown in the faulty phase, wherein the fuse blow determination unit determines that the lower arm fuse of the faulty phase has blown when the voltage output from the power conversion circuit to the winding of the faulty phase is equal to or greater than a predetermined first threshold, and determines that the upper arm fuse of the faulty phase has blown when the voltage output from the power conversion circuit to the winding of the faulty phase is equal to or less than a predetermined second threshold smaller than the first threshold.

12. The driving device according to claim 9, wherein while the switching element connected in series with the switching element determined to be the short-circuit fault location is in the on state, the fuse blow current control unit controls the driving of the other switching element so as to cancel the induced voltage generated in the windings of each phase of the rotating electrical machine except for the faulty phase.

13. A driving device including a power conversion device that outputs three-phase alternating current and a rotating electrical machine driven by the three-phase alternating current, wherein the power conversion device comprises a power conversion circuit in which at least three upper and lower arm circuits connected in series with switching elements are connected in parallel, A plurality of fuses each connected in series with the switching element of each phase of the power conversion circuit and blowing when a predetermined rated current or more flows; A short-circuit fault location determination unit that determines a short-circuit fault location of the switching element; A current control unit at the time of fuse blowing that controls driving of another switching element different from the switching element determined to be the short-circuit fault location so that the current flowing through the switching element determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse, and is provided with: The power conversion circuit has a positive electrode side wiring connected to the positive electrode side of the DC power supply and a negative electrode side wiring connected to the negative electrode side of the DC power supply; Each of the upper and lower arm circuits of each phase is connected between the positive electrode side wiring and the negative electrode side wiring, and an output line connected to each phase winding of the rotating electrical machine is connected between the switching element of the upper arm and the switching element of the lower arm; The plurality of fuses include an upper arm fuse connected in series with the switching element of the upper arm between the positive electrode side wiring and the output line, and a lower arm fuse connected in series with the switching element of the lower arm between the negative electrode side wiring and the output line in the upper and lower arm circuits of each phase; The current control unit at the time of fuse blowing is: When the temperature of another switching element different from the switching element determined to be the short-circuit fault location is less than a predetermined threshold value, the phase to which the switching element determined to be the short-circuit fault location belongs is set as a fault phase, and the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase is turned off, and the driving of the switching elements of each phase excluding the fault phase is controlled so that the current flowing through the switching element determined to be the short-circuit fault location becomes equal to or greater than the rated current of the fuse; When the temperature of another switching element different from the switching element determined to be the short-circuit fault location is equal to or greater than the threshold value, the switching element connected in series with the switching element determined to be the short-circuit fault location in the fault phase is turned on, and after either the upper arm fuse or the lower arm fuse in the fault phase is blown, the driving of another switching element different from the switching element determined to be the short-circuit fault location is controlled so that the current flowing through the other one becomes equal to or greater than the rated current of the fuse.

14. The drive device according to claim 8, wherein in each phase of the upper and lower arm circuits, output lines connected to the windings of each phase of the rotating electrical machine are respectively connected between the switching element of the upper arm and the switching element of the lower arm; the plurality of fuses include, in the upper and lower arm circuits of each phase, a triple fuse respectively connected to the switching element of the upper arm, the switching element of the lower arm, and the output line.

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