Rotating electrical machine control device

Abstract

To obtain a rotating electrical machine control device capable of suppressing heat generation at a short-circuit failure location and preventing serious failure by appropriately detecting short-circuit failures on the inverter circuit input side and performing phase short-circuit processing.SOLUTION: A rotating electrical machine control device includes: multi-phase arms with a plurality of switching elements on a positive side connected to a positive side of a DC power supply, a plurality of switching elements on a negative side connected to a negative side of the DC power supply, and a plurality of external connection points that connects the switching elements on the positive side and the switching elements on the negative side in series and are connected to windings of a rotating electrical machine; input short circuit detection portions that detect a short circuit between the positive and negative sides of the DC power supply; and a control portion that turns on all positive side switching elements or all negative side switching elements of the multi-phase arms when a short circuit is detected by the input short circuit detection portion.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This application relates to a rotating electrical machine control device.

Background Art

[0002] Recently, automobiles equipped with an electric power train such as hybrid vehicles, plug-in hybrid vehicles, electric vehicles, and fuel cell vehicles (hereinafter referred to as electrified vehicles) have become widespread. In these electrified vehicles, in addition to or as an alternative to the configuration of a conventional automobile with an internal combustion engine as a power source, a rotating electrical machine for driving wheels and an inverter circuit which is a power conversion device for driving the rotating electrical machine are mounted. In an electrified vehicle, during running, the rotating electrical machine is driven in power running to generate a running drive torque, and during braking, the rotating electrical machine is driven in regenerative operation to generate a regenerative braking torque.

[0003] Here, the drive system of an electrified vehicle includes a DC power source composed of a secondary battery such as a lithium-ion battery, an inverter circuit composed of a smoothing capacitor and a plurality of semiconductor switches connected to the DC power source, a control unit for controlling the inverter circuit, and a rotating electrical machine connected to the inverter circuit as a load. When a plurality of drive systems such as for front and rear wheels are provided, a plurality of inverter circuits and rotating electrical machines are connected to the DC power source. Also, auxiliary machines such as an air conditioner, a cooling mechanism, and a battery heater are connected to the DC power source.

[0004] In the drive system of an electrified vehicle, in order to protect the battery which is a DC power source from overvoltage and overcurrent, opening and closing means for disconnecting the battery and the inverter circuit as necessary is provided. As the opening conditions of this opening and closing means, when the voltage of the battery becomes a predetermined value or more during regenerative operation of the electric motor, when the battery voltage becomes a predetermined value or less due to battery consumption, when the current flowing through the battery becomes a predetermined value or more, etc. Further, the opening and closing means may be opened due to a vehicle failure, collision, etc.

[0005] Furthermore, a fuse is provided in series with the battery. If the inverter circuit and various auxiliary equipment connected to the battery short-circuit, a large current will flow through the fuse, causing it to blow and disconnecting the battery. In this case as well, the connection between the inverter and the DC power supply will be open.

[0006] In abnormal conditions such as those described above, where the connection between the battery and the inverter is broken, it has been proposed to perform a phase short-circuit process by turning on all of the positive or negative switching elements of the inverter circuit, thereby short-circuiting each phase of the rotating electric machine. This method aims to stop the phase current of the rotating electric machine within the inverter circuit, preventing power regeneration to the inverter circuit input. (For example, Patent Document 1) [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 9-47055 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Patent Document 1 describes a method for performing phase short-circuit processing assuming an open circuit between the battery and the inverter. However, Patent Document 1 does not describe how to handle the case where the DC power supply input to the inverter is short-circuited.

[0009] In the drive systems of such electric vehicles, if a short circuit occurs in the smoothing capacitor of the inverter circuit or in various auxiliary components for any reason, it is desirable that the short-circuited area be isolated by a switching mechanism or fuse. However, if an appropriate switching mechanism or fuse is not installed at that location, or if a large current flows in from the rotating electric machine before the circuit is isolated, the short-circuited area may overheat and lead to a serious malfunction.

[0010] This application has been made to solve the above problems, and aims to obtain a rotating electrical machine control device capable of appropriately detecting a short-circuit fault on the inverter input side and performing a phase short-circuit process, thereby suppressing heat generation at the short-circuit fault location and preventing serious faults.

Means for Solving the Problems

[0011] The rotating electrical machine control device disclosed in this application includes a plurality of-phase arms respectively provided with a positive-side switching element connected to the positive side of a DC power supply, a negative-side switching element connected to the negative side of the DC power supply, and an external connection point that connects the positive-side switching element and the negative-side switching element in series and is connected to the winding of the rotating electrical machine, an input short-circuit detection unit that detects a short circuit between the positive and negative sides of the DC power supply, a control unit that turns on all the positive-side switching elements or all the negative-side switching elements of the plurality of-phase arms when a short circuit is detected by the input short-circuit detection unit. A rotating electric machine control device, It includes an input voltage detection unit that detects the voltage between the positive and negative terminals of a DC power supply, The input short-circuit detection unit detects a short circuit when the voltage detected by the input voltage detection unit is smaller than a predetermined voltage threshold. It is equipped with a phase current detection unit that detects the phase current flowing through the windings of each phase of a rotating electric machine. The input short-circuit detection unit detects a short circuit when the voltage detected by the input voltage detection unit is less than a voltage threshold, and the phase current detected by the phase current detection unit is greater than a predetermined current threshold. Also, The rotating electric machine control device disclosed in this application is A multi-phase arm is provided with a positive-side switching element connected to the positive terminal of a DC power supply, a negative-side switching element connected to the negative terminal of a DC power supply, and an external connection point that connects the positive-side and negative-side switching elements in series and is also connected to the windings of a rotating electric machine. Input short-circuit detection unit that detects a short circuit between the positive and negative terminals of a DC power supply. A rotating electric machine control device comprising a control unit that turns on all positive-side switching elements or all negative-side switching elements of multiple phase arms when a short circuit is detected by an input short-circuit detection unit, It is equipped with a phase current detection unit that detects the phase current flowing through the windings of each phase of a rotating electric machine. The input short-circuit detection unit detects a short circuit between the positive and negative terminals of the DC power supply based on the phase current detected by the phase current detection unit. Also, The rotating electric machine control device disclosed in this application is A multi-phase arm is provided with a positive-side switching element connected to the positive terminal of a DC power supply, a negative-side switching element connected to the negative terminal of a DC power supply, and an external connection point that connects the positive-side and negative-side switching elements in series and is also connected to the windings of a rotating electric machine. Input short-circuit detection unit that detects a short circuit between the positive and negative terminals of a DC power supply. A rotating electric machine control device comprising a control unit that turns on all positive-side switching elements or all negative-side switching elements of multiple phase arms when a short circuit is detected by an input short-circuit detection unit, It is equipped with a rotational speed detection unit that detects the rotational speed of a rotating electric machine, The control unit turns off all positive and negative switching elements if the input short-circuit detection unit detects a short circuit and the rotational speed detected by the rotational speed detection unit is less than a predetermined rotational speed threshold. Also, The rotating electric machine control device disclosed in this application is A multi-phase arm is provided with a positive-side switching element connected to the positive terminal of a DC power supply, a negative-side switching element connected to the negative terminal of a DC power supply, and an external connection point that connects the positive-side and negative-side switching elements in series and is also connected to the windings of a rotating electric machine. Input short-circuit detection unit that detects a short circuit between the positive and negative terminals of a DC power supply. A rotating electric machine control device comprising a control unit that turns on all positive-side switching elements or all negative-side switching elements of multiple phase arms when a short circuit is detected by an input short-circuit detection unit, The rotating electric machine includes an overcurrent detection unit that determines that an overcurrent has occurred when the phase current flowing through the windings of each phase is greater than a predetermined overcurrent determination threshold. The control unit executes overcurrent protection processing to protect the arm if the overcurrent detection unit determines that an overcurrent has occurred, and stops the overcurrent protection processing if the input short-circuit detection unit detects a short circuit. is something.

Advantages of the Invention

[0012] According to the rotating electrical machine control device according to the present application, by appropriately detecting a short-circuit fault on the inverter input side and performing a phase short-circuit process, it is possible to suppress heat generation at the short-circuit fault location and prevent a serious fault.

Brief Description of the Drawings

[0013] [Figure 1] It is a configuration diagram of the rotating electrical machine control device according to Embodiment 1. [Figure 2] It is a hardware configuration diagram of the rotating electrical machine control device according to Embodiment 1. [Figure 3] It is a time chart showing the behavior of the phase current during an inverter input short circuit of the rotating electrical machine control device according to Embodiment 1. [Figure 4] It is a diagram showing the characteristics of the effective value of the phase current and torque with respect to the rotational speed of the rotating electrical machine according to Embodiment 1. [Figure 5] It is a configuration diagram of the rotating electrical machine control device according to Embodiment 2.

Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments of the power conversion device according to the present application will be described with reference to the drawings.

[0015] 1. Embodiment 1 <Configuration of the Rotating Electrical Machine Control Device> Figure 1 shows the configuration of a rotating electric machine control device 1 according to Embodiment 1. The rotating electric machine control device 1 is connected to a DC power supply 2 and supplied with DC current. The rotating electric machine control device 1 is connected to the DC power supply 2 and includes an inverter circuit consisting of a smoothing capacitor 10 and a plurality of semiconductor switches, and a control unit 17 that controls the inverter circuit. The inverter circuit drives the rotating electric machine 3 connected as a load.

[0016] The rotating electric machine 3 rotates the load and can regenerate the rotational energy of the load as electrical energy. The rotating electric machine 3 can be an electric motor equipped with permanent magnets on the rotor, an electric motor equipped with electromagnets on the rotor, a brushed electric motor, a brushless electric motor, etc. An efficient permanent magnet three-phase synchronous rotating electric machine may be used as the rotating electric machine 3.

[0017] The inverter circuit has three series circuits (referred to as arms) in which a positive-side switching element and a negative-side switching element are connected in series. Each of the three arms is connected in parallel to a DC power supply. The series connection points of the positive-side and negative-side switching elements of the three arms are connected to the U-phase, V-phase, and W-phase windings of the rotating electric machine 3.

[0018] Each arm of the inverter circuit consists of positive-side arms 11, 13, and 15, each having one or more positive-side switching elements connected in parallel, and negative-side arms 12, 14, and 16, each having one or more negative-side switching elements connected in parallel. The positive-side arms 11, 13, and 15 are also called upper arms, and the negative-side arms 12, 14, and 16 are also called lower arms.

[0019] A smoothing capacitor 10 is connected in parallel with each arm. The smoothing capacitor 10 suppresses ripple in the DC power supply. Furthermore, the smoothing capacitor 10 lowers the power supply impedance of the inverter circuit, improving the AC current driving capability of the inverter circuit. In addition, the smoothing capacitor 10 absorbs surge voltage.

[0020] The rotating electric machine 3 is equipped with a rotational speed detection unit 4. The rotational speed detection unit 4 may use a resolver-type encoder, an optical encoder, a Hall element, or the like. Based on the signal from the rotational speed detection unit 4, the control unit 17 calculates the rotational speed of the rotating electric machine 3.

[0021] IGBTs (Insulated Gate Bipolar Transistors) and FETs (Field Effect Transistors) may be used as switching elements for each arm. When an FET is used as the switching element, an antiparallel diode is formed due to the structure, which is called a body diode (also called a parasitic diode).

[0022] Other equipment 5 is connected to the DC power supply 2. Other equipment 5 may be auxiliary equipment such as an air conditioner, cooling mechanism, or battery heater.

[0023] <Inverter control> The inverter circuit, acting on commands from the control unit 17, switches multiple semiconductor switches on and off at a predetermined switching frequency. This converts the DC power from the DC power supply 2 into predetermined AC power. By sequentially switching the switching elements provided in each phase of the inverter circuit on and off, AC power with a phase difference of 120 degrees is supplied to each phase of the rotating electric machine 3. The control unit 17 adjusts the torque and rotational speed of the rotating electric machine 3, which is the load. Depending on the operating conditions, the rotating electric machine 3 also operates as a generator, charging the DC power supply 2 with regenerative power generated by the generator.

[0024] The control unit 17 receives the DC voltage detection value Vdc, the phase current detection values ​​iu, iv, and iw of the rotating electric machine 3, and the angle detection value θ of the rotating electric machine 3 as input. The DC voltage detection value Vdc is output from the input voltage detection unit 23. The phase current detection values ​​iu, iv, and iw are output from the phase current detection unit 22. The angle detection value θ is output from the rotation speed detection unit 4.

[0025] The control unit 17 performs the desired rotational electric machine control calculations and outputs drive signals 111, 121, 131, 141, 151, and 161 to each of the arms 11 to 16. The control unit 17 also receives the overcurrent detection signal from the overcurrent detection unit 19 and performs overcurrent protection. Furthermore, the input short-circuit detection unit 20 receives signals from the low-voltage detection unit 18, which detects when the DC voltage detection value Vdc is low, and the overcurrent detection unit 19, and outputs a short-circuit detection signal to the control unit 17 on the inverter input side.

[0026] <Hardware configuration of a rotating electric machine control device> Figure 2 is a hardware configuration diagram of the rotating electric machine control device 1 according to Embodiment 1. The hardware configuration diagram in Figure 2 can also be applied to the rotating electric machine control device 1a. Here, we will explain using the rotating electric machine control device 1 as a representative example. In this embodiment, each function of the rotating electric machine control device 1 is realized by the processing circuit provided in the rotating electric machine control device 1. Specifically, as shown in Figure 2, the rotating electric machine control device 1 includes a processing circuit consisting of a arithmetic processing unit 90 (computer) such as a CPU (Central Processing Unit), a storage device 91 that exchanges data with the arithmetic processing unit 90, an input circuit 92 that inputs external signals to the arithmetic processing unit 90, and an output circuit 93 that outputs signals from the arithmetic processing unit 90 to the outside.

[0027] The arithmetic processing unit 90 may include an ASIC (Application Specific Integrated Circuit), an IC (Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), various logic circuits, and various signal processing circuits. Furthermore, multiple arithmetic processing units 90 of the same or different types may be provided, with each unit performing a portion of the processing. The storage device 91 may include a RAM (Random Access Memory) configured to read and write data from the arithmetic processing unit 90, a ROM (Read Only Memory) configured to read data from the arithmetic processing unit 90, flash memory, etc. The input circuit 92 is connected to various sensors and switches and includes an A / D converter, etc., which inputs the output signals from these sensors and switches to the arithmetic processing unit 90. The output circuit 93 is connected to electrical loads and includes drive circuits, etc., for arms 11 to 16, which convert and output control signals from the arithmetic processing unit 90 to these electrical loads.

[0028] Each function of the rotating electric machine control device 1 is realized by the arithmetic processing unit 90 executing software (programs) stored in a storage device 91 such as a ROM, and cooperating with other hardware of the rotating electric machine control device 1, such as the storage device 91, input circuit 92, and output circuit 93. Setting data such as thresholds and judgment values ​​used by the rotating electric machine control device 1 are stored in the storage device 91 such as a ROM as part of the software (program). The functions of the components of the rotating electric machine control device 1 will now be described. Each function of the rotating electric machine control device 1 may be composed of software modules, or it may be composed of a combination of software and hardware.

[0029] <Overcurrent protection> Let's explain the overcurrent protection. The overcurrent detection unit 19 takes the phase current detection values ​​iu, iv, and iw of the rotating electric machine 3 as input. When each phase current exceeds the overcurrent threshold, it determines that an overcurrent has occurred and outputs an overcurrent detection signal to the control unit 17. When the control unit 17 receives the overcurrent detection signal, it suppresses the overcurrent by turning off all the arms. This prevents deterioration of each arm 11 to 16 and the rotating electric machine 3 due to overcurrent.

[0030] <Input short circuit fault> Figure 3 is a time chart showing the behavior of the phase current when the inverter input of the rotating electric machine control device 1 according to Embodiment 1 is short-circuited. Regarding the behavior when a short-circuit fault occurs on the inverter circuit input side, an example will be described in which the positive terminal and negative terminal of other equipment 5 connected to the DC power supply 2 are short-circuited.

[0031] Figure 3 shows, in the upper section, a time chart of the DC voltage detection value Vdc, which indicates the power supply voltage input to the inverter circuit when a short-circuit fault occurs on the inverter circuit input side. The middle section shows time charts of the phase current detection values ​​iu, iv, and iw. Furthermore, the lower section shows time charts of the d-axis current Id and q-axis current Iq, which represent the phase currents in a two-phase orthogonal coordinate system (dq coordinate system).

[0032] Immediately after a short-circuit fault, the smoothing capacitor 10 is short-circuited and discharged, and the detected DC voltage Vdc becomes approximately 0V. More specifically, the phase current from the rotating electric machine 3 flows from the inverter circuit into the minute resistance component of the short-circuit fault location, and the resulting voltage is detected as the detected DC voltage Vdc.

[0033] In the example shown in Figure 1, the inverter circuit has diodes in antiparallel to each arm 11 through 16. Therefore, even when each arm 11 through 16 is turned off, the rotating electric machine 3 still sees it as a three-phase rectifier circuit. Consequently, if the inverter circuit input is short-circuited, the rotating electric machine 3 will be in a phase short-circuit state regardless of the on / off state of each arm 11 through 16.

[0034] During on / off control, current will flow into any short-circuit fault on the inverter circuit input side. This behavior will generally occur unless all positive or negative arms are turned on.

[0035] It is generally known that when a phase short circuit occurs, the phase current waveform changes as shown by the phase current detection values ​​iu, iv, and iw in the figure, with a sharp increase in the phase current immediately after the phase short circuit. Immediately after the phase short circuit, the current is the sum of the current that flowed before the phase short circuit (hereinafter referred to as the pre-short circuit current) and the phase short circuit current that flows due to the induced voltage of the rotating electric machine 3 after the phase short circuit (hereinafter referred to as the induced voltage current). Over time, the pre-short circuit current decays and converges to the induced voltage current. The phase short circuit processing may be terminated when it is determined that the phase current detection values ​​iu, iv, and iw have converged to the induced voltage current.

[0036] <Handling of short-circuit failure in the input section> The handling of a short-circuit fault on the inverter circuit input side, which is a characteristic feature of this embodiment, will now be explained. As described above, the DC voltage detection value Vdc decreases due to a short circuit on the inverter circuit input side, so the low voltage detection unit 18 outputs a low voltage detection signal when it matches the determination condition in equation (1) below.

[0037] DC voltage detection value Vdc < Low voltage threshold (1)

[0038] Furthermore, a short circuit on the inverter circuit input side causes a phase short circuit and a rapid increase in phase current. Therefore, the overcurrent detection unit 19 outputs an overcurrent detection signal when it meets the determination condition in equation (2) below.

[0039] Phase current detection values ​​|iu, iv, iw|> Overcurrent threshold (2)

[0040] The input short-circuit detection unit 20 determines that the inverter circuit input is short-circuited when it receives both a low-voltage detection signal from the low-voltage detection unit 18 and an overcurrent detection signal from the overcurrent detection unit 19. It then outputs an input short-circuit detection signal to the control unit 17.

[0041] When the control unit 17 receives an input short-circuit detection signal, it performs phase short-circuit processing by turning on all positive side arms 11, 13, and 15 (and turning off the negative side arms), or by turning on all negative side arms 12, 14, and 16 (and turning off the positive side arms). Note that the input short-circuit detection signal is output because the phase current detection values ​​iu, iv, and iw exceed the overcurrent threshold, and as described above, the control unit 17 also receives an overcurrent detection signal from the overcurrent detection unit 19.

[0042] In this case, if the control unit 17 receives only an overcurrent detection signal, it turns off all arms and performs overcurrent protection processing. However, if an input short-circuit detection signal is input, it prioritizes and performs phase short-circuit processing.

[0043] If the inverter circuit input is short-circuited, even if all arms are turned off for overcurrent protection, the short-circuited inverter circuit input will still cause a phase short circuit. As a result, the phase current of the rotating electric machine 3 is three-phase rectified by the inverter circuit and flows entirely into the short-circuited fault.

[0044] As a result, the small resistance component at the short-circuit fault location can cause overheating, potentially leading to a serious malfunction. Therefore, when a short circuit is detected at the input, it is effective to disable overcurrent protection and perform phase short-circuit processing. This allows the phase current of the rotating electric machine 3 to recirculate within the inverter circuit, suppressing overheating at the short-circuit fault location.

[0045] The control unit 17 may continue the phase short-circuit processing after receiving the input short-circuit detection signal from the input short-circuit detection unit 20, even if either equation (1) or equation (2) is no longer satisfied. This allows the overheating prevention state at the short-circuit fault location to be maintained. This is significant because it ensures the continued prevention of overheating at the short-circuit fault location.

[0046] <Release of phase short-circuit processing when rotational speed is below the threshold> Furthermore, the control unit 17 calculates the rotational speed of the rotating electric machine 3 from the angle detection value θ output by the rotational speed detection unit 4. If the rotational speed falls below a predetermined rotational speed threshold, the phase short-circuit processing based on the input short-circuit determination may be omitted, and all arms may be turned off. The same applies if the rotational speed decreases while the phase short-circuit processing continues after the input short-circuit determination. This is because if the rotational speed of the rotating electric machine 3 falls below a predetermined rotational speed threshold, it can be estimated that the effective value of the phase current has decreased. In this case, even if all arms are turned off, the current flowing into the short-circuit fault location is considered to be sufficiently small, and it is thought that heat generation and serious failure will not occur.

[0047] <Rotational speed, phase current, and torque of a rotating electrical machine> Figure 4 shows the characteristics of the effective value of the phase current and the torque with respect to the rotational speed of the rotating electric machine 3 according to Embodiment 1. Here, we will explain the case in which the rotational speed threshold is set based on the phase current and torque during phase short-circuit processing.

[0048] The horizontal axis in Figure 4 represents the rotational speed of the rotating electric machine. It shows the characteristics of the effective value of the phase current and the torque (shown as an absolute value because it produces negative torque) during phase short-circuit processing as a function of rotational speed.

[0049] <Setting the rotational speed threshold based on phase current> Note that the effective phase current values ​​in the figure are the induced voltage currents mentioned above, and do not include the pre-short circuit currents mentioned above. The solid line in the figure represents the phase short circuit process, i.e., the state in which the inverter circuit is recirculated to short-circuit the phases, while the dashed line represents the case where the phase resistance is increased, and the graph assumes a state in which all arms are turned off and the phases are short-circuited through the minute resistance at the short-circuit fault location.

[0050] The phase current tends to decrease as the rotational speed decreases. Furthermore, the phase current tends to decrease even further as the resistance increases. Regarding torque, it tends to have a peak on the negative side at low rotational speeds. As the resistance increases, the peak point tends to shift to the higher rotational speed side.

[0051] <Setting rotational speed thresholds based on torque> Considering this trend, the rotational speed threshold is set to be below point A in the figure. By setting it this way, all arms can be turned off from the three-phase short-circuit processing at rotational speeds below the rotational speed threshold (the characteristic changes from the solid line to the dashed line in the figure). At rotational speeds below the rotational speed threshold, the phase current tends to decrease compared to high rotational speeds. Therefore, even if current flows into the short-circuit fault location in this region, heat generation is suppressed.

[0052] Furthermore, at rotational speeds below the torque peak, when all arms are turned off after a three-phase short circuit (changing from the solid line to the dashed line in the figure), the absolute value of the negative torque decreases. Therefore, for example, in the rotating electric motor used to drive electric vehicles, this changes in a direction that eliminates braking force. For this reason, even if all arms are turned off after a three-phase short circuit, the possibility of accidents due to sudden braking of the vehicle can be considered low.

[0053] Here, we have shown an example of determining the rotational speed threshold based on the induced voltage current. However, the rotational speed threshold may also be determined based on the pre-short circuit current plus the induced voltage current immediately after the phase short circuit.

[0054] When a phase short circuit occurs, the detected phase currents iu, iv, and iw show a rapid increase in phase current immediately after the phase short circuit. Immediately after the phase short circuit, the phase current is the sum of the pre-short circuit current that flowed before the phase short circuit and the induced voltage current that flows due to the induced voltage of the rotating electric machine 3 after the phase short circuit. Over time, the pre-short circuit current decays and converges to the induced voltage current. The timing and convergence value of the detected phase currents iu, iv, and iw to the induced voltage current can be confirmed by calculation, analysis, experimentation, etc., and the above rotation speed threshold can be determined.

[0055] As described above, the rotating electric machine control device 1 according to Embodiment 1 can detect when the inverter circuit input side is in a short-circuit state and perform phase short-circuit processing. This makes it possible to suppress heat generation caused by phase current flowing into the short-circuit fault location and prevent serious failures.

[0056] Furthermore, the input short-circuit detection unit 20 can detect a short-circuit fault on the inverter circuit input side using the DC voltage detection value Vdc and phase current detection values ​​iu, iv, and iw, which are necessary for the on / off control of the rotating electric machine 3. In this way, there is no need to provide a separate sensor or separate judgment value to determine the magnitude of the phase current.

[0057] Furthermore, by using the overcurrent threshold as the current threshold for detecting a short circuit on the inverter circuit input side and utilizing the judgment information of the overcurrent detection unit 19, no additional circuitry is required. Note that the current threshold for short circuit detection may be a different value from the overcurrent threshold.

[0058] Embodiment 1 described detecting a short circuit on the inverter circuit input side by determining the voltage threshold and current threshold. However, the short circuit on the inverter circuit input side may also be detected based on the phase current.

[0059] For example, the short circuit on the inverter circuit input side may be detected from numerical values ​​and time waveforms in a dq coordinate system as shown in Figure 3, using either or both of the pre-short circuit current and induced voltage current described above. This makes it possible to detect a short circuit without the need for additional sensors other than phase current detection. Alternatively, the behavior of the phase current during a short-circuit fault on the inverter circuit input side may be determined experimentally, and a short circuit on the inverter circuit input side may be determined if the movement of the phase current matches this behavior.

[0060] Furthermore, in Embodiment 1, a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) may be used as the switching element in each arm. A MOSFET has a body diode, and if a short-circuit failure occurs on the inverter circuit input side, the large current during the phase short circuit will conduct through the body diode. In this case, if a MOSFET is used, by turning on all positive-side arms or all negative-side arms to perform phase short-circuit processing, conduction in both the forward and reverse directions is possible without passing through the body diode, which has high losses, and deterioration due to heat generation of the element can be prevented. As a result, even if other equipment 5 on the inverter circuit input side experiences a short-circuit failure, deterioration of the rotating electric machine control device 1 can be suppressed.

[0061] Furthermore, while Embodiment 1 assumed IGBTs and the like made of silicon semiconductors, it is not limited to these. For example, wide-bandgap semiconductors using silicon carbide (SiC), gallium nitride-based materials, or diamond may be used. Taking SiC-MOSFETs as an example, it is known that crystal defects in SiC can proliferate due to high current conduction to the body diode, causing performance degradation.

[0062] In an inverter circuit using SiC-MOSFETs, the phase short-circuit processing by short-circuit detection, a feature of Embodiment 1, can be implemented. This suppresses the degradation of the SiC-MOSFET by preventing large currents from being conducted through the body diode or by shortening the conduction time. As a result, even if other equipment 5 on the inverter circuit input side experiences a short-circuit failure, the degradation of the rotating electric machine control device 1 can be suppressed.

[0063] 2. Embodiment 2 <Speed-up through analog and logic circuits> Figure 5 is a configuration diagram of the rotating electric machine control device 1a according to Embodiment 2. In the rotating electric machine control device 1 according to Embodiment 1, each function of the rotating electric machine control device 1 may be composed of software modules. In the rotating electric machine control device 1a according to Embodiment 2, the low voltage detection unit 18a, the overcurrent detection unit 19a, and the input short circuit detection unit 20a are composed of analog circuits such as operational amplifiers and comparators, or logic circuits such as AND and OR, or a combination of analog circuits and logic circuits, and are not composed of software modules.

[0064] In the rotating electric machine control device 1a according to Embodiment 2, the analog logic circuit 30 of the control unit 17a receives signals from the DC voltage detection value Vdc, phase current detection values ​​iu, iv, and iw on the inverter circuit input side, as well as signals from the low voltage detection unit 18a, the overcurrent detection unit 19a, and the input short circuit detection unit 20a, and responds to short circuits on the inverter circuit input side. When a short circuit is detected on the inverter circuit input side, the analog logic circuit 30 executes control to turn on all switching elements on the positive side arm or all switching elements on the negative side arm. The analog logic circuit 30 is composed of an analog circuit, a logic circuit, or a combination of an analog circuit and a logic circuit, and is not composed of a software module, and is separate from the processing of the arithmetic processing unit 90 provided in the rotating electric machine control device 1a.

[0065] This configuration allows for faster processing compared to when a arithmetic processing unit 90, such as a CPU (Central Processing Unit), executes software stored in a storage device 91, such as a ROM, to detect a short circuit on the inverter circuit input side and perform phase short circuit processing.

[0066] By implementing the processing of the low-voltage detection unit 18a using analog circuits, logic circuits, or a combination thereof, rather than software, it is possible to speed up short-circuit detection by the input short-circuit detection unit 20a. Furthermore, by performing overcurrent detection by the overcurrent detection unit 19a using analog circuits, it is possible to reduce the delay time during overcurrent protection and short-circuit detection.

[0067] Instead of sequentially reading and executing software from a storage device 91 such as ROM, the detection of short circuits on the inverter circuit input side and the execution of phase short-circuit processing can be accelerated by performing logical operations using analog circuits, logic circuits, or a configuration combining them.

[0068] While this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are envisioned within the scope of the art disclosed herein. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with a component from another embodiment.

[0069] The various aspects of this disclosure are summarized below as an appendix.

[0070] (Note 1) A multi-phase arm is provided with a positive-side switching element connected to the positive terminal of a DC power supply, a negative-side switching element connected to the negative terminal of the DC power supply, and an external connection point that connects the positive-side switching element and the negative-side switching element in series and is connected to the winding of a rotating electric machine. An input short-circuit detection unit that detects a short circuit between the positive and negative terminals of the DC power supply. A rotating electric machine control device comprising a control unit that turns on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms when the input short-circuit detection unit detects the short circuit. (Note 2) The DC power supply is equipped with an input voltage detection unit that detects the voltage between the positive and negative terminals, The rotating electric machine control device according to Appendix 1, wherein the input short-circuit detection unit detects the short circuit when the voltage detected by the input voltage detection unit is smaller than a predetermined voltage threshold. (Note 3) The rotating electric machine is equipped with a phase current detection unit that detects the phase current flowing through the windings of each phase, The rotating electric machine control device according to Appendix 2, wherein the input short-circuit detection unit detects the short circuit when the voltage detected by the input voltage detection unit is less than the voltage threshold and the phase current detected by the phase current detection unit is greater than a predetermined current threshold. (Note 4) The control unit, when the input short-circuit detection unit detects a short circuit, turns on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms, and continues to turn on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms until the voltage detected by the input voltage detection unit is equal to or greater than the voltage threshold and the phase current detected by the phase current detection unit is equal to or less than the current threshold, as described in Appendix 3 of the rotating electric machine control device. (Note 5) The rotating electric machine includes an overcurrent detection unit that determines that an overcurrent has occurred when the phase current flowing through the windings of each phase is greater than a predetermined overcurrent determination threshold. When the control unit determines that an overcurrent has occurred, it performs an overcurrent protection process to protect the arm. The rotating electric machine control device according to Appendix 2, wherein the input short-circuit detection unit detects the short circuit when the voltage detected by the input voltage detection unit is smaller than the voltage threshold and the overcurrent detection unit determines that an overcurrent has occurred. (Note 6) The rotating electric machine control device according to Appendix 2, wherein the input short-circuit detection unit compares the voltage detected by the input voltage detection unit with the voltage threshold using an analog circuit or a logic circuit. (Note 7) The rotating electric machine control device according to Appendix 3, wherein the input short-circuit detection unit performs a comparison between the voltage detected by the input voltage detection unit and the voltage threshold, and a comparison between the phase current detected by the phase current detection unit and the current threshold, using an analog circuit or a logic circuit. (Note 8) The rotating electric machine is equipped with a phase current detection unit that detects the phase current flowing through the windings of each phase, The rotating electric machine control device according to Appendix 1, wherein the input short-circuit detection unit detects the short circuit between the positive and negative terminals of the DC power supply based on the phase current detected by the phase current detection unit. (Note 9) The rotating electric machine is equipped with a rotation speed detection unit that detects the rotation speed of the rotating electric machine, The control unit, if the input short-circuit detection unit detects the short circuit and the rotational speed detected by the rotational speed detection unit is less than a predetermined rotational speed threshold, turns off all positive-side switching elements and negative-side switching elements, as described in any one of the appendices 1 to 8. (Note 10) The rotating electric machine control device according to Appendix 9, wherein the rotational speed threshold of the control unit is set based on the convergence value of the phase current when all positive-side switching elements or all negative-side switching elements of the multiple-phase arms are turned on. (Note 11) The rotating electric machine control device according to Appendix 9, wherein the rotational speed threshold of the control unit is set based on the torque generated in the rotating electric machine when all positive-side switching elements or all negative-side switching elements of the multi-phase arms are turned on. (Note 12) The control unit, after a short circuit is detected by the input short-circuit detection unit, keeps all positive-side switching elements or all negative-side switching elements of the multiple-phase arms turned on, as described in any one of the appendices 1 to 8. (Note 13) The rotating electric machine includes an overcurrent detection unit that determines that an overcurrent has occurred when the phase current flowing through the windings of each phase is greater than a predetermined overcurrent determination threshold. The rotating electric machine control device according to any one of the appendices 1 to 8, wherein the control unit performs an overcurrent protection process to protect the arm when the overcurrent detection unit determines that an overcurrent has occurred, and the overcurrent protection process is stopped when the input short-circuit detection unit detects the short circuit. (Note 14) The control unit, when it is determined by the overcurrent detection unit that an overcurrent has occurred, turns off all positive-side switching elements and all negative-side switching elements as an overcurrent protection process to protect the arm, as described in any one of the appendices 1 to 13. (Note 15) The rotating electric machine control device according to any one of the appendices 1 to 14, wherein the switching element is a MOS-FET. (Note 16) The rotating electric machine control device according to any one of the appendices 1 to 15, wherein the switching element is made of a wide bandgap semiconductor. [Explanation of Symbols]

[0071] 1, 1a Rotating electric machine control device, 2 DC power supply, 3 Rotating electric machine, 4 Rotation speed detection unit, 11, 13, 15 Positive side arm, 12, 14, 16 Negative side arm, 17, 17a Control unit, 18, 18a Low voltage detection unit, 19, 19a Overcurrent detection unit, 20, 20a Input short circuit detection unit, 22 Phase current detection unit, 23 Input voltage detection unit, 30 Analog logic circuit

Claims

1. A multi-phase arm is provided with a positive-side switching element connected to the positive terminal of a DC power supply, a negative-side switching element connected to the negative terminal of the DC power supply, and an external connection point that connects the positive-side switching element and the negative-side switching element in series and is connected to the winding of a rotating electric machine. An input short-circuit detection unit that detects a short circuit between the positive and negative terminals of the DC power supply. A rotating electric machine control device comprising a control unit that turns on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms when the input short-circuit detection unit detects the short circuit, The DC power supply is equipped with an input voltage detection unit that detects the voltage between the positive and negative terminals, The input short-circuit detection unit detects a short circuit when the voltage detected by the input voltage detection unit is smaller than a predetermined voltage threshold. The rotating electric machine is equipped with a phase current detection unit that detects the phase current flowing through the windings of each phase, The input short-circuit detection unit is a rotating electric machine control device that detects a short circuit when the voltage detected by the input voltage detection unit is less than the voltage threshold and the phase current detected by the phase current detection unit is greater than a predetermined current threshold.

2. The control unit turns on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms when the input short-circuit detection unit detects the short circuit, and continues to turn on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms until the voltage detected by the input voltage detection unit is equal to or greater than the voltage threshold and the phase current detected by the phase current detection unit is equal to or less than the current threshold, according to claim 1.

3. The rotating electric machine includes an overcurrent detection unit that determines that an overcurrent has occurred when the phase current flowing through the windings of each phase is greater than a predetermined overcurrent determination threshold. When the control unit determines that an overcurrent has occurred, it performs an overcurrent protection process to protect the arm. The rotating electric machine control device according to claim 1, wherein the input short-circuit detection unit detects the short circuit when the voltage detected by the input voltage detection unit is smaller than the voltage threshold and the overcurrent detection unit determines that an overcurrent has occurred.

4. The rotating electric machine control device according to claim 1, wherein the input short-circuit detection unit compares the voltage detected by the input voltage detection unit with the voltage threshold using an analog circuit or a logic circuit.

5. The rotating electric machine control device according to claim 1, wherein the input short-circuit detection unit performs a comparison between the voltage detected by the input voltage detection unit and the voltage threshold, and a comparison between the phase current detected by the phase current detection unit and the current threshold, using an analog circuit or a logic circuit.

6. A multi-phase arm each provided with a positive-side switching element connected to the positive side of a DC power supply, a negative-side switching element connected to the negative side of the DC power supply, and an external connection point that connects the positive-side switching element and the negative-side switching element in series and is connected to a winding of a rotating electric machine, An input short-circuit detection unit that detects a short circuit between the positive and negative terminals of the DC power supply. A rotating electric machine control device comprising a control unit that turns on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms when the input short-circuit detection unit detects the short circuit, The rotating electric machine is equipped with a phase current detection unit that detects the phase current flowing through the windings of each phase, The input short-circuit detection unit is a rotating electric machine control device that detects the short circuit between the positive and negative terminals of the DC power supply based on the phase current detected by the phase current detection unit.

7. A multi-phase arm each provided with a positive-side switching element connected to the positive side of a DC power supply, a negative-side switching element connected to the negative side of the DC power supply, and an external connection point that connects the positive-side switching element and the negative-side switching element in series and is connected to a winding of a rotating electric machine, An input short-circuit detection unit that detects a short circuit between the positive and negative terminals of the DC power supply. A rotating electric machine control device comprising a control unit that turns on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms when the input short-circuit detection unit detects the short circuit, The rotating electric machine is equipped with a rotation speed detection unit that detects the rotation speed of the rotating electric machine, The control unit is a rotating electric machine control device that, when the input short-circuit detection unit detects a short circuit and the rotational speed detected by the rotational speed detection unit is less than a predetermined rotational speed threshold, turns off all positive-side switching elements and negative-side switching elements.

8. The rotating electric machine control device according to claim 7, wherein the rotation speed threshold of the control unit is set based on the convergence value of the phase current when all positive-side switching elements or all negative-side switching elements of the multiple-phase arms are turned on.

9. The rotating electric machine control device according to claim 7, wherein the rotation speed threshold of the control unit is set based on the torque generated in the rotating electric machine when all positive-side switching elements or all negative-side switching elements of the multiple-phase arms are turned on.

10. The control unit, after a short circuit is detected by the input short-circuit detection unit, keeps all positive-side switching elements or all negative-side switching elements of the multiple-phase arms turned on, as described in claim 1.

11. A multi-phase arm each provided with a positive-side switching element connected to the positive side of a DC power supply, a negative-side switching element connected to the negative side of the DC power supply, and an external connection point that connects the positive-side switching element and the negative-side switching element in series and is connected to a winding of a rotating electric machine, An input short-circuit detection unit that detects a short circuit between the positive and negative terminals of the DC power supply. A rotating electric machine control device comprising a control unit that turns on all positive-side switching elements or all negative-side switching elements of the multiple-phase arms when the input short-circuit detection unit detects the short circuit, The rotating electric machine includes an overcurrent detection unit that determines that an overcurrent has occurred when the phase current flowing through the windings of each phase is greater than a predetermined overcurrent determination threshold. The control unit performs an overcurrent protection process to protect the arm when the overcurrent detection unit determines that an overcurrent has occurred, and stops the overcurrent protection process when the input short-circuit detection unit detects the short circuit.

12. The rotating electric machine control device according to claim 11, wherein the control unit turns off all positive-side switching elements and all negative-side switching elements as an overcurrent protection process to protect the arm when the overcurrent detection unit determines that an overcurrent has occurred.

13. The rotating electric machine control device according to any one of claims 1 to 12, wherein the switching element is a MOS-FET.

14. The rotating electric machine control device according to any one of claims 1 to 12, wherein the switching element is formed of a wide bandgap semiconductor.

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