Rotating electric machine control device

Abstract

To obtain a rotary electric machine control device which can operate while a semiconductor switching element is protected by properly changing a restriction value of a command value for driving a rotary electric machine on the basis of the state of an output current but the current is not excessively restricted.SOLUTION: A rotary electric machine control device includes a power conversion circuit having a positive electrode-side switching element and a negative electrode-side switching element, a voltage sensor, a phase current detection sensor, and a control unit that performs on / off control on the switching elements on the basis of a current command value, and determines whether to restrict a torque command value on the basis of a voltage so as to cause torque command value restriction means to set the torque command value to be equal to or less than a first torque restriction value when the current is equal to or larger than a predetermined switching current, and cause the torque command value restriction means to set the torque command value to be equal to or less than a second torque restriction value which is greater than the first torque restriction value when the current is smaller than the switching current.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present application relates to a rotating electrical machine control device. [Background technology]

[0002] Common rotating electrical machine control devices that convert the form of power output include an AC / DC (Alternate Current / Direct Current) converter that converts AC power to DC power, an inverter that converts DC power to AC power, etc. These rotating electrical machine control devices often include a configuration equipped with semiconductor switching elements.

[0003] The semiconductor switching elements of a rotating electric machine control device have a predetermined withstand voltage performance, and a rotating electric machine control device has been proposed that is equipped with an overvoltage protection means that detects the voltage applied to the semiconductor switching elements, and if the detected voltage rises and exceeds a predetermined overvoltage threshold Vov, stops the rotating electric machine control device to prevent destruction due to overvoltage (OV).

[0004] In particular, a load dump during regenerative operation, in which the power line connecting the battery and the rotary electric machine control device becomes open while the rotary electric machine is in regenerative operation, can be considered a worst-case scenario for an increase in input voltage. In this case, it is necessary to quickly limit the current to prevent the semiconductor switching elements from being damaged when the peak voltage exceeds the withstand voltage of the semiconductor switching elements when they are turned off during overvoltage protection.

[0005] By reducing the current when the semiconductor switching element is turned off, it is possible to suppress the surge voltage when the semiconductor switching element is turned off. For this reason, a technique has been proposed that limits the output current at a stage before determining whether overvoltage protection is required (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 5-219759 Summary of the Invention [Problem to be solved by the invention]

[0007] In Patent Document 1, the output current limit value is changed according to the voltage of the DC power supply. In the worst case scenario, such as when a load dump occurs during regeneration, the DC power supply voltage rises sharply. Therefore, it is necessary to detect the voltage rise of the DC power supply at a stage before determining whether overvoltage protection is required, and to quickly limit the output current.

[0008] However, if the current is significantly limited in response to a rise in the DC power supply voltage, adverse effects may occur. If the output current is excessively limited even when an overvoltage is not detected, the performance of the rotating electrical machine may be impaired.

[0009] The present application discloses a technique for solving the above-mentioned problems, and aims to provide a rotating electric machine control device that detects the voltage of a DC power supply of the rotating electric machine control device to implement overvoltage protection, and that can operate without excessively limiting the current while protecting semiconductor switching elements by appropriately changing the limit value of a command value that drives the rotating electric machine based on the state of the output current, thereby reducing the current when operation is stopped due to overvoltage protection. [Means for solving the problem]

[0010] The rotating electrical machine control device according to the present application comprises: a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between the positive and negative poles of the power conversion circuit; a phase current detection sensor for detecting a phase current flowing between an external connection point of the power conversion circuit and the rotating electric machine; and a control unit that controls the on / off of switching elements based on a current command value calculated from a torque command value received from outside, determines whether or not the torque command value should be limited based on a voltage detected by a voltage sensor, and when it is determined that the torque command value should be limited, executes first limiting processing by torque command value limiting means to set the torque command value to a first torque limit value or less if the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current, and when it is determined that the torque command value should be limited, executes second limiting processing by torque command value limiting means to set the torque command value to a second torque limit value or less that is greater than the first torque limit value if the current detected by the phase current detection sensor is smaller than the switching current.

[0011] Further, the rotating electric machine control device according to the present application is a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between the positive and negative poles of the power conversion circuit; a phase current detection sensor for detecting a phase current flowing between an external connection point of the power conversion circuit and the rotating electric machine; and a control unit that controls the on / off of a switching element based on a current command value calculated from a torque command value received from the outside, determines whether or not the current command value should be limited based on a voltage detected by a voltage sensor, and when it is determined that the current command value should be limited, executes first limiting processing by current command value limiting means to set the current command value to a first current limit value or less if the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current, and when it is determined that the current command value should be limited, executes second limiting processing by current command value limiting means to set the current command value to a second current limit value or less that is greater than the first current limit value if the current detected by the current detection sensor is smaller than the switching current.

[0012] Furthermore, the rotating electrical machine control device according to the present application is a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between the positive and negative poles of the power conversion circuit; a phase current detection sensor for detecting a phase current flowing between an external connection point of the power conversion circuit and the rotating electric machine; and a control unit that calculates a current command value from a torque command value received from an external source, calculates a d-axis voltage command value and a q-axis voltage command value from the current command value, and performs on / off control of switching elements based on the d-axis voltage command value and the q-axis voltage command value, and determines whether the d-axis voltage command value and the q-axis voltage command value should be limited based on a voltage detected by a voltage sensor, and when it is determined that the d-axis voltage command value and the q-axis voltage command value should be limited, if the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current, performs first limiting processing by means of voltage command value limiting means to set the d-axis voltage command value and the q-axis voltage command value to equal to or less than a first d-axis voltage limit value and a first q-axis voltage limit value, respectively; and when it is determined that the d-axis voltage command value and the q-axis voltage command value should be limited, if the current detected by the current detection sensor is smaller than the switching current, performs second limiting processing by means of voltage command value limiting means to set the d-axis voltage command value and the q-axis voltage command value to equal to or less than a second d-axis voltage limit value and a second q-axis voltage limit value that are greater than the first d-axis voltage limit value and the first q-axis voltage limit value. [Effects of the Invention]

[0013] According to the rotating electric machine control device of the present application, by appropriately changing the limit value of the command value that drives the rotating electric machine based on the state of the output current, it is possible to obtain a rotating electric machine control device that can operate without excessively restricting the current while reducing the current when operation is stopped due to overvoltage protection and protecting the semiconductor switching elements. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a configuration diagram of a rotary electric machine control device according to a first embodiment. [Figure 2] 2 is a hardware configuration diagram of a control unit of the rotary electric machine control device according to the first embodiment. FIG. [Figure 3] 2 is a functional block diagram of a control unit of the rotary electric machine control device according to the first embodiment. FIG. [Figure 4] 4 is a state transition diagram of a torque command limiting unit of a control unit of the rotary electric machine control device according to the first embodiment. FIG. [Figure 5A]10 is a first time chart showing the behavior of a comparative example of a rotary electric machine control device during a voltage rise. [Figure 5B] 10 is a second time chart showing the behavior of the comparative example of the rotary electric machine control device during a voltage rise. [Figure 6A] 4 is a first time chart showing the behavior of the rotary electric machine control device according to the first embodiment when a voltage rises. [Figure 6B] 10 is a second time chart showing the behavior of the rotary electric machine control device according to the first embodiment when voltage increases. [Figure 7] FIG. 10 is a configuration diagram of a rotary electric machine control device according to a second embodiment. [Figure 8] FIG. 10 is a functional block diagram of a control unit of a rotary electric machine control device according to a second embodiment. [Figure 9] FIG. 10 is a state transition diagram of a current command limiting unit of a control unit of a rotary electric machine control device according to a second embodiment. [Figure 10A] 10 is a first time chart showing the behavior of the rotary electric machine control device according to the second embodiment when voltage increases. [Figure 10B] 10 is a second time chart showing the behavior of the rotary electric machine control device according to the second embodiment when voltage increases. [Figure 11] FIG. 10 is a configuration diagram of a rotary electric machine control device according to a third embodiment. [Figure 12] FIG. 11 is a functional block diagram of a control unit in a rotary electric machine control device according to a third embodiment. [Figure 13] FIG. 11 is a state transition diagram of a voltage command limiting unit of a control unit of a rotary electric machine control device according to a third embodiment. [Figure 14A] 10 is a first time chart showing the behavior of the rotary electric machine control device according to the third embodiment when voltage increases. [Figure 14B] 10 is a second time chart showing the behavior of the rotary electric machine control device according to the third embodiment when voltage increases. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, preferred embodiments of a rotary electric machine control device according to the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals.

[0016] 1. First Embodiment The configuration of a rotating electric machine control device 100 according to a first embodiment will be described with reference to Fig. 1. The rotating electric machine control device 100 is intended for use in electrically powered vehicles such as electric vehicles and plug-in hybrid vehicles, and is intended to drive a rotating electric machine 10 powered by electric power from a high-voltage battery. The rotating electric machine control device 100 is often configured to include semiconductor switching elements.

[0017] Semiconductor switching elements include diodes, which allow current to flow in only one direction; thyristors, which are suitable for handling large currents; and power transistors, which are power semiconductor switching elements capable of operating at high switching frequencies. Among semiconductor switching elements, power transistors in particular are used in a wide range of fields, including automobiles, refrigerators, and air conditioners. Power transistors include IGBTs (Insulated Gate Bipolar Transistors) and MOS-FETs (Metal-Oxide-Semiconductor Field-Effect Transistors), and these power transistors are used for a variety of purposes.

[0018] In recent years, silicon carbide (SiC) and gallium nitride (GaN) have been attracting attention as materials for semiconductor switching elements. Compared to semiconductor switching elements made of conventional silicon (Si), semiconductor switching elements made of these wide bandgap semiconductor materials have lower resistance in the on-state, which reduces power loss. They also have high electron saturation velocities, allowing for quick switching between on and off states.

[0019] There is a method for turning off semiconductor switching elements when the input voltage is overvoltage by using overvoltage protection for the semiconductor switching elements. For example, in a rotating electric machine control device 100 that is installed in an electric vehicle and operates a rotating electric machine 10 using battery energy, the peak voltage, including a voltage surge, tends to increase when the semiconductor switching elements are turned off by overvoltage protection due to the following factors based on recent trends.

[0020] - Higher battery voltage (400V and 800V series) to reduce charging times. Increased voltage surges due to the ability of wide bandgap semiconductors such as SiC and GaN to quickly switch from on to off and on to off states. Increased output current due to higher output of rotating electrical machine control devices, resulting in increased voltage surges. Worst-case input voltage rise during load dump during regeneration operation.

[0021] Load dump refers to the state in which the power line connecting the rotating electric machine control device 100 and the DC power source 12, which is typically a battery, is opened. The rotating electric machine control device 100 receives power from the rotating electric machine 10 during regenerative operation, and the battery is connected to the rotating electric machine control device 100 as a load to be charged. When this battery is disconnected, current is concentrated in the rotating electric machine control device 100 due to load disconnection (load dump), and the supply voltage rises.

[0022] This is because when the power line connecting the battery and the rotating electric machine control device 100 is opened during a load dump, the regenerative energy of the rotating electric machine 10 cannot be transferred to the battery and is instead stored in the capacitor 21 connected in parallel to the battery in the rotating electric machine control device. The worst case scenario during a load dump during regenerative operation is when a large amount of energy is stored in the capacitor 21, causing a sudden rise in voltage; specifically, this scenario assumes a load dump that occurs when the vehicle decelerates while the rotating electric machine 10 is rotating at high speed, resulting in a large amount of regenerative energy.

[0023] <Configuration of a rotating electrical machine control device> 1 illustrates a DC power supply 12, such as a battery, which supplies DC power to the rotating electric machine control device 100 and is charged with regenerative power, and a rotating electric machine 10. Note that the object to be controlled is not limited to the rotating electric machine 10, and may be something other than the rotating electric machine 10.

[0024] 1, the rotating electric machine control device 100 is connected to a DC power supply 12 by a positive DC bus 1a and a negative DC bus 1b, and exchanges driving power and regenerative power with the DC power supply 12. The rotating electric machine control device 100 is also connected to a rotating electric machine 10 by an AC bus 2, and exchanges driving power and regenerative power with the rotating electric machine 10.

[0025] The rotating electric machine 10 is also provided with a rotation angle sensor 11 that detects a rotation angle θm of the rotating electric machine (rotation angle θm is not shown). The rotating electric machine 10 is capable of rotating a load and regenerating the rotational energy of the load as electrical energy, and may use, for example, a permanent magnet three-phase AC synchronous motor or a three-phase brushless motor.

[0026] The rotating electric machine control device 100 includes a power conversion unit 20 and a control unit 90. The power conversion unit 20 includes a capacitor 21 connected between a positive-side DC bus 1a and a negative-side DC bus 1b on the DC power supply input side, a voltage detection unit 24 (also referred to as a voltage sensor) that detects the DC bus voltage of the power conversion unit 20, and a plurality of switching elements. The power conversion unit 20 also includes an inverter circuit 25 that performs DC / AC power conversion, and a phase current detection unit 26 (also referred to as a phase current sensor) that detects the phase current of the rotating electric machine 10 flowing through the AC bus 2.

[0027] The control unit 90 includes a drive circuit 27 that performs drive control to switch the switching elements on and off. In the example shown in Fig. 1, the drive circuit 27 is built into the control unit 90 as an output circuit of the control unit 90. However, the drive circuit 27 may be provided separately from the control unit 90.

[0028] Capacitor 21 has functions such as suppressing ripples in the DC bus voltage, lowering the power supply impedance of power conversion unit 20 to improve the AC current driving capability of power conversion unit 20, and absorbing surge voltage. Furthermore, voltage detection unit 24 divides the DC bus voltage using a voltage dividing resistor or the like to a voltage that can be read by control unit 90, and outputs DC bus voltage information to control unit 90.

[0029] The inverter circuit 25 is an inverter in which six commonly known semiconductor switching elements (hereinafter referred to as switching elements) are fully bridge-connected. That is, as shown in Fig. 1, switching elements 51 and 52, switching elements 53 and 54, and switching elements 55 and 56 configure three legs in which a positive-side (upper-stage) switching element and a negative-side (lower-stage) switching element are connected in series, and are connected in parallel to the DC power supply 12.

[0030] In addition, the midpoints of switching elements 51 and 52 are connected to the U-phase input of the rotating electric machine 10, the midpoints of switching elements 53 and 54 are connected to the V-phase input of the rotating electric machine 10, and the midpoints of switching elements 55 and 56 are connected to the W-phase input of the rotating electric machine 10.

[0031] 1, switching elements 51, 52, 53, 54, 55, and 56 are respectively built into semiconductor modules 61, 62, 63, 64, 65, and 66. The switching elements are, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) with diodes built between the source and drain as shown in Fig. 1. However, the type and number of switching elements are not limited to these, and other switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and SiC-MOSFETs may also be used.

[0032] The phase current detection unit 26 is configured with a U-phase current detection unit 261, a V-phase current detection unit 262, and a W-phase current detection unit 263. The U-phase current detection unit 261, the V-phase current detection unit 262, and the W-phase current detection unit 263 are configured using, for example, shunt resistors. The U-phase current detection unit 261 outputs a U-phase current detection value corresponding to the U-phase current Iu to the control unit 90. The V-phase current detection unit 262 outputs a V-phase current detection value corresponding to the V-phase current Iv to the control unit 90. The W-phase current detection unit 263 outputs a W-phase current detection value corresponding to the W-phase current Iw to the control unit 90. In the following description, the U-phase current detection value, the V-phase current detection value, and the W-phase current detection value may be collectively referred to as current detection values. The phase current detection unit 26 may also be a current sensor using a Hall element or the like.

[0033] The drive circuit 27 is controlled based on a PWM signal from the control unit 90. The drive circuit 27 has a function of switching the switching elements 51-56 on and off.

[0034] The rotation angle sensor 11 detects the rotor rotation angle θm of the rotating electric machine 10 using a resolver, an encoder, etc. The rotor rotation angle θm detected by the rotation angle sensor 11 is output to the control unit 90. The rotor rotation angle θm is converted into an electrical angle θe based on the number of pole pairs of the rotating electric machine 10.

[0035] <Hardware configuration of the control unit> FIG. 2 is a hardware configuration diagram of a control unit 90 of a rotating electric machine control device 100 according to the first embodiment. In this embodiment, the control unit 90 is a control device that controls the rotating electric machine control device 100. The hardware configuration diagram in FIG. 2 can also be applied to control units 90B and 90C. Here, the control unit 90 will be described as a representative. Each function of the control unit 90 is realized by a processing circuit provided in the control unit 90. Specifically, the control unit 90 includes, as processing circuits, an arithmetic processing device 80 (computer) such as a CPU (Central Processing Unit), a storage device 81 that exchanges data with the arithmetic processing device 80, an input circuit 82 that inputs external signals to the arithmetic processing device 80, and an output circuit 83 that outputs signals from the arithmetic processing device 80 to the outside.

[0036] The arithmetic processing device 80 may be an application specific integrated circuit (ASIC), an integrated circuit (IC), a digital signal processor (DSP), a field programmable gate array (FPGA), various logic circuits, various signal processing circuits, etc. Furthermore, a plurality of the same or different types of arithmetic processing devices 80 may be provided, with each device performing a different process. The storage device 81 may be a random access memory (RAM) configured to be able to read and write data from the arithmetic processing device 80, a read only memory (ROM) configured to be able to read data from the arithmetic processing device 80, etc. The input circuit 82 includes the rotation angle sensor 11, the voltage detection unit 24, and the phase current detection unit 26, and is connected to various sensors and switches. The input circuit 82 is equipped with interface circuits such as an AD conversion unit and an input circuit that inputs output signals from these sensors and switches to the arithmetic processing device 80. The output circuit 83 includes a drive circuit 27, and is connected to electrical loads such as switching elements and actuators. The output circuit 83 is equipped with interface circuits such as a drive circuit that converts and outputs output signals from the arithmetic processing unit 80 to these electrical loads, and a communication circuit.

[0037] Each function of the control unit 90 is realized by the arithmetic processing device 80 executing software (programs) stored in a storage device 81 such as a ROM, and cooperating with other hardware of the control unit 90 such as the storage device 81, an input circuit 82, and an output circuit 83. Setting data such as thresholds and judgment values ​​used by the control unit 90 is stored in the storage device 81 such as a ROM as part of the software (programs).

[0038] Each function installed inside the control unit 90 may be configured as a software module, or may be configured as a combination of software and hardware.

[0039] <Controller function block> 3 is a functional block diagram of a control unit 90 of the rotating electric machine control device 100 according to Embodiment 1. In Fig. 3, the control unit 90 includes a determination unit 91, a torque command limiting unit 92, a current command generating unit 93, a three-phase to two-phase conversion unit 94, a voltage command generating unit 95, a two-phase to three-phase conversion unit 96, a duty conversion unit 97, a PWM signal generating unit 98, and an overvoltage protection unit 99.

[0040] The judgment unit 91 receives the input voltage Vpn, which is the detection value of the voltage detection unit 24, and when the input voltage Vpn exceeds a first voltage threshold Vth1, it judges that the phase current should be limited and sets a judgment value S1 to Hi. Thereafter, when the input voltage Vpn becomes equal to or less than a second voltage threshold Vth2, it sets the judgment value S1 to Lo (the initial value of the judgment value S1 is Lo) (Vth2 is not shown). The first voltage threshold Vth1 is a voltage value that is greater than the voltage range in which the rotating electrical machine control device can ratedly operate and less than the overvoltage threshold Vov. The second voltage threshold Vth2 is equal to or less than the first voltage threshold Vth1 and has a hysteresis characteristic that prevents frequent mode transitions due to fluctuations in the detected value of the input voltage.

[0041] The torque command limiting unit 92 receives as input an effective current value Irms obtained by converting the current detection value detected by the phase current detecting unit 26 into an effective value, a judgment value S1 output from the judging unit 91, and a torque command value Trq* from a higher-level system (not shown). Note that the control command for controlling the rotating electric machine 10 may be, for example, a torque command, a current command, a voltage command, etc. In the first embodiment, a case where the torque command value Trq* is used as the control command will be exemplified.

[0042] If the judgment value S1 output from the judgment unit 91 is Lo, the torque command limiting unit 92 generates the input torque command value Trq* as a limited torque command value Trqc* without limiting it, and if the judgment value S1 is Hi, it generates a limited torque command value Trqc* by setting the upper limit value of the input torque command value Trq* to a first torque limit value Trq_mx1 (this is called the first limiting process) (the first torque limit value Trq_mx1 is not shown).

[0043] Furthermore, if the judgment value S1 is Hi and the effective current value Irms is below the switching current value Ij after the first limiting process is performed, a second limiting process is performed to set the upper limit of the torque command value Trq* to a second torque limit value Trq_mx2. A more detailed configuration of the torque command limiting unit 92 will be described later (the second torque limit value Trq_mx2 is not shown).

[0044] The current command generator 93 generates a d-axis current command value Id* and a q-axis current command value Iq* based on this post-limitation torque command value Trqc*. Here, the d-axis indicates the magnetic pole position of the rotating electric machine 10, i.e., the direction of the magnetic flux, and the q-axis indicates a direction electrically perpendicular to the d-axis, forming a dq-axis coordinate system. The dq-axis coordinate system is a rotating coordinate system, and when the rotor of the rotating electric machine 10, which has a magnet, rotates, the dq-axis coordinate system also rotates.

[0045] The three-phase / two-phase conversion unit 94 calculates a d-axis current detection value Id and a q-axis current detection value Iq from the current detection values ​​of the phase current detection unit 26 and an angle detection value corresponding to the electrical angle θe detected by the rotation angle sensor 11. Here, the current detection values ​​of the phase current detection unit 26 are composed of a U-phase current detection value corresponding to the U-phase current Iu detected by a U-phase current detection unit 261, a V-phase current detection value corresponding to the V-phase current Iv detected by a V-phase current detection unit 262, and a W-phase current detection value corresponding to the W-phase current Iw detected by a W-phase current detection unit 263.

[0046] The voltage command generation unit 95 calculates a d-axis voltage command value Vdc* and a q-axis voltage command value Vqc* by performing current feedback calculations using the d-axis current command value Id*, the q-axis current command value Iq*, and the d-axis current detection value Id and the q-axis current detection value Iq. Specifically, for example, the voltage command generation unit 95 is configured to calculate the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* so that a current deviation ΔId, which is the deviation between the d-axis current command value Id* and the d-axis current detection value Id, and a current deviation ΔIq, which is the deviation between the q-axis current command value Iq* and the q-axis current detection value Iq, converge to "0" (ΔId and ΔIq are not shown). Here, "calculation" includes calculating a numerical value using a formula, deriving a numerical value based on map data or values ​​obtained by interpolating or extrapolating from map data, and a combination of these.

[0047] The two-phase / three-phase conversion unit 96 calculates three-phase voltage commands Vuc, Vvc, and Vwc from the d-axis voltage command value Vdc* and q-axis voltage command value Vqc* obtained from the voltage command generation unit 95 and the electrical angle θe obtained from the rotation angle sensor 11. It is preferable that the three-phase voltage commands Vuc, Vvc, and Vwc are set to be equal to or less than the DC power supply voltage input to the power conversion unit 20, i.e., the input voltage Vpn detected by the voltage detection unit 24.

[0048] The duty conversion unit 97 generates duty commands Du, Dv, Dw for each of the three phases from the three-phase voltage commands Vuc, Vvc, Vwc obtained from the two-phase / three-phase conversion unit 96 and the input voltage Vpn.

[0049] The PWM signal generating unit 98 generates a PWM signal based on the duty commands Du, Dv, and Dw for each phase acquired from the duty converting unit 97, to generate a PWM signal for controlling the on / off switching of each of the switching elements 51 to 56.

[0050] Specifically, the PWM signal generating unit 98 generates a PWM signal by comparing the duty commands Du, Dv, and Dw of each phase with a carrier wave. The PWM signal generating unit 98 is configured to generate a PWM signal by employing, for example, a triangular wave comparison method or a sawtooth wave comparison method in which a triangular wave having an isosceles triangle shape with equal rising and falling speeds serves as the carrier.

[0051] In Figure 3, the PWM signals generated by the PWM signal generation unit 98 are shown as PWM signal UH_S to be given to switching element 51 of the U-phase upper arm, PWM signal VH_S to be given to switching element 53 of the V-phase upper arm, PWM signal WH_S to be given to switching element 55 of the W-phase upper arm, PWM signal UL_S to be given to switching element 52 of the U-phase lower arm, PWM signal VL_S to be given to switching element 54 of the V-phase lower arm, and PWM signal WL_S to be given to switching element 56 of the W-phase lower arm.

[0052] The overvoltage protection unit 99 receives the PWM signal generated by the PWM signal generation unit 98 as input and generates a PWM signal based on the input voltage Vpn. Specifically, if the input voltage Vpn is less than a predetermined overvoltage threshold Vov, the PWM signal generated by the PWM signal generation unit 98 is used as the PWM signal output by the overvoltage protection unit. If the input voltage Vpn is equal to or greater than the overvoltage threshold Vov, overvoltage protection is performed by turning off the positive-side switching element and turning on the negative-side switching element, turning on the positive-side switching element and turning off the negative-side switching element, or turning off both the positive-side switching element and the negative-side switching element. This overvoltage protection unit 99 realizes the overvoltage protection function when the input voltage becomes an overvoltage.

[0053] The PWM signals generated by the overvoltage protection unit 99 are a PWM signal UH provided to switching element 51 of the U-phase upper arm, a PWM signal VH provided to switching element 53 of the V-phase upper arm, a PWM signal WH provided to switching element 55 of the W-phase upper arm, a PWM signal UL provided to switching element 52 of the U-phase lower arm, a PWM signal VL provided to switching element 54 of the V-phase lower arm, and a PWM signal WL provided to switching element 56 of the W-phase lower arm. The PWM signals generated by the overvoltage protection unit 99 are input to a drive circuit 27 in the control unit 90. The drive circuit 27 turns on and off switching elements 51 to 56 based on the PWM signals, thereby converting DC power into AC power and supplying it to the rotating electric machine 10, and charging DC power supply 12 with regenerative power generated by the rotating electric machine 10 in a regenerative state.

[0054] Here, a feature of the rotary electric machine control device 100 according to the first embodiment is that the determination unit 91 determines whether or not the phase current should be limited based on the input voltage Vpn. If the input voltage Vpn is greater than a first voltage threshold Vth1, the determination unit 91 determines that the phase current should be limited, and the torque command limiting unit 92 performs first limiting processing in which the upper limit value of the torque command value Trq* is set to a first torque limit value Trq_mx1.

[0055] Furthermore, when the effective current value Irms is lower than the switching current value Ij, a second limiting process is performed in which the upper limit value of the torque command value Trq* is set to the second torque limit value Trq_mx2. Also, a feature of the rotating electrical machine control device 100 according to the first embodiment is that the second torque limit value Trq_mx2 is larger than the first torque limit value Trq_mx1.

[0056] <Current limiter operation> The operation of the torque command limiting unit 92, which is a feature of the rotating electrical machine control device 100 according to the first embodiment, will be described below with reference to Fig. 4. Fig. 4 is a state transition diagram (also referred to as a state chart diagram) showing the operation of the torque command limiting unit 92. When the mode in which the rotating electrical machine control device 100 is performing normal operation is a normal operation mode 921, and the input voltage Vpn increases and the judgment value S1 output from the judgment unit 91 becomes Hi, the process proceeds to first limiting processing 922. In the first limiting processing 922, the upper limit value of the torque command value Trq* is set to a first torque limit value Trq_mx1.

[0057] Furthermore, if the effective current value Irms is lower than the switching current value Ij, the process proceeds to second limiting process 923. In the second limiting process 923, the upper limit value of the torque command value Trq* is set to a second torque limit value Trq_mx2.

[0058] When the input voltage Vpn becomes equal to or lower than the second voltage threshold Vth2, the judgment value S1 output from the judgment unit 91 becomes Lo, and the operation mode changes from the first limiting process 922 or the second limiting process 923 to the normal operation mode 921. In the normal operation mode 921, the setting of the upper limit value of the torque command value Trq* is released, and the motor operates normally.

[0059] <Determination of the second torque limit value> The second torque limit value Trq_mx2 in the second limiting process 923 is set to a value equal to or less than the overvoltage withstand current Iov_mx, which is a current value at which the switching elements 51 to 56 are not damaged when the switching elements are turned off by the overvoltage protection function of the overvoltage protection unit 99.

[0060] <Determining the first torque limit value> The first torque limit value Trq_mx1 in the first limiting process 922 is a value that can limit the phase current to the overvoltage withstand current Iov_mx, which is a current value at which the switching elements 51 to 56 do not fail, during the worst case scenario in which the input voltage rises sharply, from the time when the input voltage Vpn exceeds the first voltage threshold Vth1 and the judgment unit 91 determines that the phase current should be limited, until the overvoltage protection unit 99 turns off the switching elements.

[0061] <Operational Description of Comparative Example> The switching current value Ij in the first limiting process 922 is set to be equal to or less than the overvoltage withstand current Iov_mx, which is a current value at which the switching elements 51 to 56 are not broken when the switching elements are turned off by the overvoltage protection function of the overvoltage protection unit 99.

[0062] Here, a comparative example will be described to illustrate the effect of setting an upper limit value of the command value by the torque command limiting unit 92 based on the determination by the determining unit 91, which is a feature of the first embodiment. Fig. 5A is a first time chart showing the behavior of the comparative example of the rotating electrical machine control device when a sudden voltage rises. Fig. 5B is a second time chart showing the behavior of the comparative example of the rotating electrical machine control device when a gradual voltage rises.

[0063] In the comparative example, the current is limited according to the input voltage. Figure 5A shows a case where the current is limited by taking into account the worst-case scenario of a steep input voltage rise. When the input voltage exceeds the first voltage threshold Vth1, the target current (shown by the solid line) is reduced to the current limit value I_mx, rapidly reducing the actual effective current Irms (shown by the dashed line). Therefore, if all switching elements are turned off when the input voltage exceeds the overvoltage threshold Vov, the current can be significantly limited to below the overvoltage withstand current Iov_mx, which is sufficient to prevent the switching elements from breaking down. At time tov, overvoltage protection is activated, and the current command value becomes the overvoltage target current Iov (current 0 Arms) (shown by the solid line). Then, all switching elements 51 to 56 are turned off, and the effective current Irms begins to decrease with a delay.

[0064] Here, the first voltage threshold Vth1 is set to a value slightly larger than the maximum voltage value at which the rotating electrical machine control device should operate at its rated capacity. In the worst case scenario of a load dump during regenerative operation, the voltage rises sharply as shown in Fig. 5A, so the time from time t1 when the input voltage exceeds the first voltage threshold Vth1, at which limiting of the output current begins, to time tov when the input voltage reaches the overvoltage threshold Vov becomes very short.

[0065] Therefore, in order to reduce the current to the current value Iov_mx at which the switching element will not break down in that short time, it is necessary to limit the current limit value (target current value) I_mx to a sufficiently small value at time t1, taking into account the responsiveness of the current to the command value. Therefore, it is necessary to significantly reduce the upper limit value of the torque command value Trq* so that the current command value can be sufficiently limited.

[0066] 5B shows the time waveforms of the input voltage and current when the operation of the rotating electric machine control device continues after the input voltage exceeds the first voltage threshold Vth1 without reaching the overvoltage threshold Vov. In this case, too, when the input voltage exceeds the first voltage threshold Vth1, the target current (shown by the solid line) is reduced to the current limit value I_mx, and the actual effective current value Irms (shown by the dashed line) is rapidly reduced. Therefore, even if the input voltage does not reach the overvoltage threshold Vov, the actual effective current value Irms may decrease to near the current limit value I_mx, excessively limiting the output current and potentially impairing the performance of the rotating electric machine.

[0067] <Explanation of Operation of First Embodiment> Fig. 6A is a first time chart showing the behavior of the rotating electrical machine control device 100 according to embodiment 1 when there is a sudden voltage rise. Fig. 6B is a second time chart showing the behavior of the rotating electrical machine control device 100 according to embodiment 1 when there is a gradual voltage rise. A case where an upper limit value of the torque command value Trq* is set by the torque command limiting unit 92 based on the determination by the determination unit 91 in Fig. 1, which is a feature of embodiment 1, will be described with reference to Fig. 6A.

[0068] 6A shows the time waveforms of the input voltage Vpn and the phase current effective value Irms when overvoltage protection is activated in the worst case scenario of a steep rise in the input voltage Vpn. The input voltage Vpn rises and exceeds the first voltage threshold Vth1 at time t1, at which point the target current drops to the first current command value Ic1. Accordingly, the actual phase current effective value Irms drops to or below the overvoltage withstand current Iov_mx, at which point the switching elements will not fail, at time tov when overvoltage protection is activated.

[0069] This is achieved when the input voltage Vpn exceeds the first voltage threshold Vth1, causing the judgment value S1 of the judgment unit 91 to become Hi, causing the torque command limiting unit 92 to transition to first limiting processing 922, where the upper limit of the torque command value Trq* is limited to the first torque limit value Trq_mx1. By setting the upper limit of the torque command value Trq* to the first torque limit value Trq_mx1, the current command value determined by the post-limitation torque command value Trqc* is reduced. As a result, the current value when the switching element is turned off by overvoltage protection at time tov is reduced, and by suppressing the surge voltage, it is possible to prevent damage to the switching element.

[0070] At time tov, overvoltage protection is activated, and the current command value becomes the overvoltage target current Iov (current 0 Arms). Then, all switching elements 51 to 56 are turned off, and the effective current value Irms begins to decrease with a delay.

[0071] 6B shows the time waveforms of the input voltage Vpn and the phase current effective value Irms when the input voltage Vpn exceeds the first voltage threshold Vth1 but does not reach the overvoltage threshold Vov and the operation of the rotary electric machine control device 100 continues. At time t1, the target current decreases to the first current command value Ic1, as in FIG. 6A. This series of steps is the same as in FIG. 6A.

[0072] Thereafter, operation continues without the input voltage Vpn reaching the overvoltage threshold Vov, and at time t2 the target current rises to the second current command value Ic2. This is achieved by the torque command limiting unit 92 transitioning to second limiting processing 923 when the phase current effective value Irms falls below the switching current value Ij, and limiting the upper limit of the torque command value Trq* to the second torque limit value Trq_mx2. As a result, the current command value determined by the post-limitation torque command value Trqc* rises to the second current command value Ic2, allowing operation to continue without excessively limiting the current.

[0073] In the technology of the comparative example, the current is limited according to the input voltage. In contrast, in the rotating electric machine control device 100 according to the first embodiment, when the input voltage Vpn exceeds the first voltage threshold Vth1 and the phase current effective value Irms calculated from the phase current detection value of the phase current detection unit 26 is equal to or greater than the switching current value Ij, the first limiting process limits the torque command value Trq* using the first torque limit value Trq_mx1, thereby lowering the upper limit of the current command value. Then, when the phase current effective value Irms falls below the switching current value Ij, the second limiting process limits the torque command value Trq* using the second torque limit value Trq_mx2, thereby raising the upper limit. This reduces the current when operation is stopped due to overvoltage protection, suppresses voltage surges, and prevents breakdown of switching elements. Furthermore, during continued operation, the rotating electric machine 10 can continue to operate without excessively limiting the output of the rotating electric machine control device 100.

[0074] In the above description, the upper limit of the torque command value Trq* is set by the first torque limit value Trq_mx1 and the second torque limit value Trq_mx2. However, instead of the torque command value Trq*, the upper limit may be set by the d-axis current command value Id*, the q-axis current command value Iq*, or the target phase current effective value Irms, each of which has its upper limit set by the first current limit value Imx1 or the second current limit value Imx2.

[0075] <Effects when the first embodiment is applied> The determination unit 91 of the control unit 90 of the rotary electric machine control device 100 according to the first embodiment determines that the torque command value Trq* should be limited when the input voltage Vpn exceeds the first voltage threshold Vth1. This makes it possible to determine the state in which the current command value should be limited with a simple configuration using only information about the input voltage.

[0076] Furthermore, in the torque command limiting unit 92 of this embodiment, the phase current is limited by setting the command upper limit value to a first torque limit value Trq_mx1 in a first limiting process 922, and the first torque limit value Trq_mx1 is set to a value smaller than the second torque limit value Trq_mx2. This makes it possible to continue operation at the largest possible output while preventing failure when the switching elements are turned off during overvoltage protection.

[0077] In addition, in this embodiment, the phase current is limited by limiting the upper limit of the torque command value Trq* using the torque command limiting unit 92. This limits the phase current using a higher-level control command value in the control system of the rotary electric machine control device, thereby enabling continuous and stable operation of the entire control system, and easily suppressing the phase current when the switching element is turned off during overvoltage protection, thereby preventing damage to the switching element.

[0078] Furthermore, in this embodiment, when the input voltage Vpn exceeds the first voltage threshold Vth1 and then falls to or below the second voltage threshold Vth2, the judgment value S1 output from the judgment unit 91 is switched from Hi to Lo, and the first and second limiting processes in the torque command limiting unit 92 are cancelled. As a result, when the input voltage reaches a level at which the rotary electric machine control device can operate at a rated level, the rotary electric machine control device returns to normal operation, and can continue to operate without limiting the current.

[0079] Furthermore, in the torque command limiting unit 92 of this embodiment, the second torque limit value Trq_mx2 is a value that is equal to or less than the overvoltage withstand current Iov_mx, a current value that will not break the switching elements when the switching elements are turned off by the overvoltage protection function. In other words, the second torque limit value Trq_mx2 is a value derived by tracing back the process of deriving the current command value from the torque command value so that the current command value is equal to or less than the overvoltage withstand current Iov_mx. This makes it possible to continue operation at the largest possible output while preventing breakdown of the switching elements.

[0080] Furthermore, in the torque command limiting unit 92 of this embodiment, the switching current value Ij is equal to or less than the overvoltage withstand current Iov_mx, which is the current value at which the switching element will not be broken when the switching element is turned off by the overvoltage protection function. As a result, once the current value reaches a value at which the switching element will not be broken, the current limit is immediately relaxed to the second torque limit value Trq_mx2, so that the switching element can be operated at the largest possible output while preventing breakdown.

[0081] In this embodiment, the first torque limit value Trq_mx1 of the torque command limiting unit 92 is a value that can limit the phase current to the overvoltage withstand current Iov_mx or less, which is a current value that will not cause breakdown of the switching elements, from the time the determination unit 91 makes a determination until the switching elements are turned off by the overvoltage protection function. This reduces the current when operation is stopped due to overvoltage protection, even in the worst case scenario of a steep input voltage rise, and prevents breakdown of the switching elements. In addition, since the upper limit of the command value is limited without stopping operation, operation can be continued at the maximum possible output.

[0082] In this embodiment, the first voltage threshold Vth1 of the determination unit 91 is a voltage higher than the voltage range in which the rotary electric machine control device can operate rated. As a result, when the input voltage becomes higher than the voltage range in which the rotary electric machine control device can operate rated, it is determined that the current should be limited immediately and a command upper limit value is set, thereby making it possible to prevent failure when the switching element is turned off during overvoltage protection.

[0083] Furthermore, in this embodiment, the switching elements 51 to 56 may be formed of wide bandgap semiconductors such as SiC, GaN, etc. Wide bandgap semiconductors are characterized by their ability to quickly switch from on to off and from off to on, resulting in a high rate of change in current and a large surge voltage, but by using the rotating electric machine control device 100 according to the first embodiment, it is possible to prevent failures when the switching elements are turned off during overvoltage protection, and to operate the rotating electric machine control device 100 without excessively restricting its output during continued operation.

[0084] As described above, the rotating electric machine control device 100 of the first embodiment performs a first limiting process in which the torque command limiting unit 92 sets the upper limit of the torque command value Trq* to a first torque limit value Trq_mx1 when the input voltage increases and the determination unit 91 determines that the phase current should be limited. Furthermore, when the effective current value Irms is lower than the switching current value Ij, the torque command limiting unit 92 performs a second limiting process in which the upper limit of the torque command value Trq* is set to a second torque limit value Trq_mx2. This reduces the current when the switching elements are turned off due to overvoltage protection, thereby suppressing voltage surges and preventing breakdown of the switching elements, while allowing the rotating electric machine control device to operate without excessively limiting the output during continued operation. Furthermore, the first embodiment eliminates the need to use elements with high withstand voltage performance in consideration of surge voltages when the switching elements are turned off due to overvoltage protection, thereby reducing costs.

[0085] 2. Second Embodiment The rotating electric machine control device 200 according to the second embodiment has two differences from the rotating electric machine control device 100 according to the first embodiment. The first difference is that, while in the first embodiment the torque command value Trq* is limited by the first torque limit value Trq_mx1 and the second torque limit value Trq_mx2, in the second embodiment the d-axis current command value Id*, the q-axis current command value Iq*, or the target effective current value Irms is limited by the first limit d-axis current command value Idc1*, the first limit q-axis current command value Iqc1*, or the first current limit value Imx1, and is limited by the second limit d-axis current command value Idc2*, the second limit q-axis current command value Iqc2*, or the second current limit value Imx2. (The first limit d-axis current command value Idc1*, the first limit q-axis current command value Iqc1*, the second limit d-axis current command value Idc2*, and the second limit q-axis current command value Iqc2* are not shown.)

[0086] The second difference is that while the determination unit 91 according to the first embodiment uses the input voltage Vpn to determine whether or not the torque command value Trq* should be limited, the determination unit 91B according to the second embodiment uses the input voltage Vpn as well as the effective current value Irms detected from the current detection value to determine whether or not the current command value needs to be limited. The determination by the determination unit 91B according to the second embodiment may be changed in the same way as the determination unit 91 according to the first embodiment.

[0087] The configuration and operation of a rotating electrical machine control device 200 according to the second embodiment will be described below with reference to Figs. 7 to 10, focusing on the differences from the first embodiment. Note that parts that are the same as or equivalent to those in the first embodiment are given the same reference numerals. To distinguish from the first embodiment, the components are referred to as a rotating electrical machine control device 200, a control unit 90B, a determination unit 91B, and a current command limiting unit 92B.

[0088] 7 is a configuration diagram of a rotating electric machine control device 200 according to embodiment 2. The rotating electric machine control device 200 is configured with a power conversion unit 20 and a control unit 90B. The power conversion unit 20 is the same as that of the rotating electric machine control device 100 according to embodiment 1, but the function of the control unit 90B is different from that of the rotating electric machine control device 100 according to embodiment 1.

[0089] <Controller function block> Fig. 8 is a functional block diagram of a control unit 90B of a rotary electric machine control device 200 according to embodiment 2. In Fig. 8, the control unit 90B has a determination unit 91B, a current command limiting unit 92B, a current command generating unit 93, a three-phase to two-phase conversion unit 94, a voltage command generating unit 95, a two-phase to three-phase conversion unit 96, a duty conversion unit 97, a PWM signal generating unit 98, and an overvoltage protection unit 99.

[0090] The three-phase to two-phase converter 94, voltage command generator 95, two-phase to three-phase converter 96, duty converter 97, PWM signal generator 98 and overvoltage protector 99 have the same functions as those in embodiment 1. Therefore, their description will be omitted.

[0091] The judgment unit 91B receives the input voltage Vpn, which is the detection value of the voltage detection unit 24, and the current effective value Irms, which is the current detection value detected by the phase current detection unit 26 converted into an effective value. When the input voltage Vpn exceeds the first voltage threshold Vth1 and the current effective value Irms is equal to or greater than the current threshold Ith, the judgment unit 91B determines that the phase current should be limited and sets the judgment value S1 to Hi, and thereafter, when the input voltage Vpn becomes equal to or less than the second voltage threshold Vth2, sets the judgment value S1 to Lo (the initial value of the judgment value S1 is Lo). The current threshold Ith is set to be equal to or less than the overvoltage withstand current Iov_mx, which is the current value at which the switching elements will not be damaged when the rotating electrical machine control device is stopped by the overvoltage protection function (the current threshold Ith is not shown).

[0092] As in the first embodiment, the first voltage threshold Vth1 is set to a voltage value that is greater than the rated operable voltage range of the rotary electric machine control device 200 and less than the overvoltage threshold Vov. Also, as in the first embodiment, the second voltage threshold Vth2 is equal to or less than the first voltage threshold Vth1 and has a hysteresis characteristic that can prevent frequent mode transitions due to fluctuations in the detected value of the input voltage.

[0093] A torque command value Trq* is input from a higher-level system (not shown) to the current command generator 93. Based on this torque command value Trq*, the current command generator 93 generates a d-axis current command value Id* and a q-axis current command value Iq*.

[0094] The current command limiting unit 92B receives the effective current value Irms, a judgment value S1 that is the output of the judgment unit 91B, and the d-axis current command value Id* and the q-axis current command value Iq* from the current command generating unit 93. If the judgment value S1 is Lo, the current command limiting unit 92B generates the d-axis current command value Idc* and the q-axis current command value Iq* as limited d-axis current command values ​​Idc* and limited q-axis current command values ​​Iqc* without limiting them, and if the judgment value S1 is Hi, it generates the limited d-axis current command value Idc* and the limited q-axis current command value Iqc* by setting the upper limit values ​​of the input d-axis current command value Id* and q-axis current command value Iq* to a first current limit value Imx1 (this is referred to as first limiting processing).

[0095] Furthermore, if the judgment value S1 is Hi and the effective current value Irms is below the switching current value Ij after the first limiting process is performed, the upper limit values ​​of the input d-axis current command value Id* and q-axis current command value Iq* are set to the second current limit value Imx2 to generate a post-limiting d-axis current command value Idc* and a post-limiting q-axis current command value Iqc* (this is called the second limiting process).

[0096] Regarding the setting of the second current limit value Imx2, first, the current value at which the switching element will not be damaged when stopped by the overvoltage protection function is set to Ia. Then, the q-axis current command value Iq* is given priority for limiting. Then, Ia=√((Id* 2 +Iq* 2 ) / 3), the upper limit of the q-axis current command value Iq* is √(3×Ia 2 -Id* 2 ) The upper limit of the d-axis current command value Id* is Ia=√((Id* 2 +0) / 3) gives √3×Ia. These are the second current limit values ​​Imx2.

[0097] The first current limit value Imx1 is set in the same manner as the second current limit value Imx2. Specifically, in the worst case scenario where the input voltage increases sharply, the current is limited to the overvoltage withstand current Iov_mx, which is the current value at which the switching elements 51 to 56 do not break down, during the period from when the input voltage Vpn increases and the determination unit 91 determines that the phase current should be limited until the overvoltage protection unit 99 turns off the switching elements, and Imx1 is set as the current value. The method for deriving the second current limit value Imx2 in this case is the same as above. However, the upper limit value is set as the upper limit value for the absolute values ​​of the input d-axis current command value Id* and q-axis current command value Iq*. A more detailed configuration of the current command limit unit 92B will be described later.

[0098] A feature of the rotary electric machine control device 200 according to the second embodiment is that a determination unit 91B determines whether the phase currents should be limited based on the input voltage Vpn and the current detection value, and if the determination unit 91B determines that the phase currents should be limited, first performs a first limiting process in which the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* are set to a first current limiting value Imx1, and then, if the effective current value Irms is lower than the switching current value Ij, performs a second limiting process in which the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* are set to a second current limiting value Imx2. Similarly to the feature of the rotary electric machine control device 100 according to the first embodiment, the second current limiting value Imx2 is greater than the first current limiting value Imx1.

[0099] <Current limiter operation> 9 is a state transition diagram of the current command limiting unit 92B of the control unit 90B of the rotary electric machine control device 200 according to Embodiment 2. The operation of the current command limiting unit 92B, which is a feature of the rotary electric machine control device 200, will be described below.

[0100] 9 is also referred to as a state chart diagram showing the operation of the current command limiting unit 92B. When the mode in which the rotary electric machine control device 200 is operating normally is a normal operation mode 921B and the determination unit 91B determines that the current should be limited and the determination value S1 is Hi, the process proceeds to a first limiting process 922B. In the first limiting process 922B, the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* are limited and set by a first current limiting value Imx1.

[0101] Furthermore, if the effective current value Irms is lower than the switching current value Ij, the process proceeds to a second limiting process 923B, in which the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* are limited and set by a second current limit value Imx2.

[0102] When the input voltage Vpn becomes equal to or lower than the second voltage threshold Vth2, the judgment value S1 output by the judgment unit 91B becomes Lo, and the mode transitions from the first limiting process 922B or the second limiting process 923B to the normal operation mode 921B. In the normal operation mode 921B, the settings of the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* are canceled.

[0103] <Determining the Second Current Limit Value> The second current limit value Imx2 in the second limiting process 923B is set to be equal to or less than the overvoltage withstand current Iov_mx, which is a current value at which the switching elements 51 to 56 are not broken when the switching elements are turned off by the overvoltage protection function of the overvoltage protection unit 99.

[0104] <Determining the first current limit value> The first current limit value Imx1 in the first limiting process 922B is a value that can limit the phase current to the overvoltage withstand current Iov_mx, which is a current value at which the switching elements 51 to 56 do not fail, during the worst case scenario in which the input voltage rises sharply, from the time when the input voltage Vpn exceeds the first voltage threshold Vth1 and the judgment unit 91B judges that the phase current should be limited, until the overvoltage protection unit 99 turns off the switching elements.

[0105] <Determining the current threshold> The current threshold Ith in the determination unit 91B is set to be equal to or less than the overvoltage withstand current Iov_mx, which is a current value at which the switching elements 51 to 56 are not broken when the switching elements are turned off by the overvoltage protection function of the overvoltage protection unit 99.

[0106] <Comparison between the technology of the comparative example and the second embodiment> Next, a description will be given of the effect of setting an upper limit value of the command value by current command limiting unit 92B based on the determination by determining unit 91B, which is a feature of embodiment 2. The problem with the technique of the comparative example used to describe the effect is the same as the explanation of the operation performed in embodiment 1 using Figures 5A and 5B, and if the current is limited assuming the worst case scenario of a load dump during regenerative operation in Figure 5A, the problem is that if the operation in Figure 5B continues, the current must be excessively limited during operation.

[0107] 10A and 10B, a case where the first limiting process and the second limiting process are performed by the current command limiting unit 92B based on the determination by the determination unit 91B, which is a feature of the second embodiment, will be described. Fig. 10A shows the time waveforms of the input voltage Vpn and the phase current effective value Irms when overvoltage protection is activated in the worst case scenario of a steep input voltage increase, and Fig. 10B shows the waveforms when the input voltage exceeds the first voltage threshold Vth1 but does not reach the overvoltage threshold Vov and the operation of the rotary electric machine control device continues.

[0108] In the worst case scenario of FIG. 10A , where the input voltage rises sharply, the current command value is first reduced to the first current command value Ic1 at time t1 when the input voltage Vpn exceeds the first voltage threshold Vth1. The actual current value then decreases to or below the overvoltage withstand current Iov_mx, the current value at which the switching elements will not fail, at time tov when overvoltage protection is activated. This is achieved by the following: When the input voltage Vpn exceeds the first voltage threshold Vth1 and the current value is equal to or greater than the current threshold Ith, the determination value S1 of the determination unit 91B becomes Hi. This causes the current command limiting unit 92B to transition to the first limiting process 922B, where the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* are limited to and set to the first current limit value Imx1. This reduces the current value when the switching elements are turned off by overvoltage protection, suppressing surge voltages and preventing breakdown of the switching elements.

[0109] Next, referring to FIG. 10B, which shows the case where operation continues after the input voltage exceeds the first voltage threshold Vth1, the actual current value drops at time t1, as in FIG. 10A. This is for the same reason as in FIG. 10A. After that, operation continues without the input voltage reaching the overvoltage threshold Vov. At time t2, the current command value increases, and the actual RMS current value Irms also increases. This is achieved by the current command limiting unit 92B transitioning to the second limiting process 923B when the current falls below the switching current value Ij. This is achieved by limiting and setting the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* to a second current limit value Imx2, which is higher than the first current limit value Imx1. This allows the upper limits of the command values ​​to be set appropriately, enabling operation without excessive current limiting.

[0110] 10B shows an example in which the effective current value Irms is equal to or less than the switching current value Ij before time t2, but the second limiting process is not performed until time t2 due to a delay in control.

[0111] In the technology of the comparative example, the current is limited in accordance with the input voltage Vpn, so that the current is limited excessively, whereas in the second embodiment, by using information on the effective current value Irms detected from the current detection value in addition to the input voltage Vpn, the upper limit value of the current command value is reduced to a first current limit value Imx1 or less in the first limiting process, and then the command upper limit value is raised to a second current limit value Imx2 in the second limiting process. This reduces the current when operation is stopped due to overvoltage protection and suppresses voltage surges, thereby preventing damage to the switching elements 51 to 56, and allows operation without excessively limiting the output of the rotating electrical machine control device 200 when operation continues.

[0112] <Effects when the second embodiment is applied> The determination unit 91B of the second embodiment determines that the current should be limited when the input voltage Vpn exceeds the first voltage threshold Vth1 and the effective current value is equal to or greater than the current threshold Ith. In this way, by using not only the information on the input voltage Vpn from the voltage detection unit but also the information on the current from the current detection unit, it is possible to operate without needlessly limiting the current under conditions where the current value is equal to or less than the overvoltage withstand current Iov_mx, which is the current value at which the switching element will not break down, even if the voltage is such that the output may be limited.

[0113] Furthermore, the current command limiting unit 92B of the second embodiment limits the phase current by limiting the upper limits of the d-axis current command value Id* and the q-axis current command value Iq*. In this way, by limiting the current command value with a short control cycle in the control system of the rotary electric machine control device, when the determining unit 91B determines that the current should be limited, the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* can be quickly limited to quickly reduce the current. As a result, even if the time between when the input voltage rises above the rated voltage and when it reaches the overvoltage threshold Vov is short, the phase current can be quickly suppressed when the switching element is turned off due to overvoltage protection, and damage to the switching element can be prevented.

[0114] In the determination unit 91B of the second embodiment, the current threshold value Ith is set to be equal to or less than the overvoltage withstand current Iov_mx, which is a current value at which the switching elements 51 to 56 will not be damaged when the switching elements are turned off by the overvoltage protection function of the overvoltage protection unit 99. This allows operation without unnecessary current restriction in the case of a current value at which the switching elements will not be damaged when turned off by overvoltage protection.

[0115] As described above, the rotating electric machine control device 200 of the second embodiment determines that the phase current should be limited when the input voltage Vpn exceeds the first voltage threshold Vth1 and the effective current value Irms is equal to or greater than the current threshold Ith, and performs a first limiting process of setting the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* to the second control upper limit value, and a second limiting process of setting the upper limits of the d-axis current command value Id* and the q-axis current command value Iq* to the first control upper limit value when the current falls below the switching current value Ij. This reduces the current when the switching elements are turned off due to overvoltage protection, suppressing voltage surges and preventing breakdown of the switching elements, while allowing the rotating electric machine control device to operate without excessively limiting its output during continuous operation.

[0116] 3. Embodiment 3 The rotating electric machine control device 300 of the third embodiment differs from the rotating electric machine control device 100 of the first embodiment in three points. The first difference is that in the first embodiment, the torque command value Trq* is limited by the torque command limiting unit 92, whereas in the third embodiment, the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* are limited by the voltage command limiting unit 92C. The second difference is that in the first embodiment, the determining unit 91 determines whether to limit the current using the value of the input voltage Vpn, whereas in the third embodiment, the determination is made using the change in the input voltage per unit time in addition to the value of the input voltage.

[0117] The third difference is that in the first limiting process, in the first embodiment, the current is reduced by setting the command upper limit value to the first torque limit value Trq_mx1 and the second torque limit value Trq_mx2, whereas in the third embodiment, the current is reduced by turning off the switching element or by the second d-axis voltage limit value Vd_mx2 and the second q-axis voltage limit value Vq_mx2 (the second d-axis voltage limit value Vd_mx2 and the second q-axis voltage limit value Vq_mx2 are not shown).

[0118] In the rotating electric machine control device 300 according to the third embodiment, the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* may be limited based on the value of the input voltage Vpn, similarly to the rotating electric machine control device 100 according to the first embodiment. Furthermore, instead of turning off all the switching elements, the upper limits of the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* may be limited to a first voltage limit value.

[0119] <Configuration of a rotating electrical machine control device> The configuration and operation of the rotating electric machine control device according to the third embodiment will be described below with reference to Figs. 11 to 14, focusing on the differences from the first embodiment. Note that the same or equivalent parts as those in the first embodiment are given the same reference numerals. To distinguish from the first embodiment, the components are referred to as a rotating electric machine control device 300, a control unit 90C, a determination unit 91C, and a voltage command limiting unit 92C.

[0120] 11 is a configuration diagram of a rotating electric machine control device 300 according to embodiment 3. The rotating electric machine control device 300 is configured with a power conversion unit 20 and a control unit 90C. The power conversion unit 20 is the same as that of the rotating electric machine control device 100 according to embodiment 1, but the function of the control unit 90C differs from that of the rotating electric machine control device 100 according to embodiment 1.

[0121] The configuration and functions of the control unit 90C will be described below. <Controller function block> Fig. 12 is a functional block diagram of a control unit 90C of a rotary electric machine control device 300 according to embodiment 2. In Fig. 12, the control unit 90C has a determination unit 91C, a voltage command limiting unit 92C, a current command generating unit 93, a three-phase-to-two-phase conversion unit 94, a voltage command generating unit 95, a two-phase-to-three-phase conversion unit 96, a duty conversion unit 97, a PWM signal generating unit 98, an overvoltage protection unit 99, and a cutoff unit 901. The three-phase-to-two-phase conversion unit 94, the voltage command generating unit 95, the two-phase-to-three-phase conversion unit 96, the duty conversion unit 97, the PWM signal generating unit 98, and the overvoltage protection unit 99 have the same functions as those in embodiment 1, and therefore description thereof will be omitted.

[0122] The input voltage Vpn, which is the detection value of the voltage detection unit 24, is input to the determination unit 91C. When the input voltage Vpn exceeds the first voltage threshold Vth1 and when the input voltage rises by a predetermined voltage value or more in a predetermined time, the determination unit 91C determines that the phase current should be limited and sets the determination value S1 to Hi, and thereafter, when the input voltage Vpn falls to a second voltage threshold Vth2 or less, sets the determination value S1 to Lo (the initial value of the determination value S1 is Lo). The predetermined time is the detection cycle of the voltage detection unit 24. The predetermined voltage value is a value at which the input voltage may reach the overvoltage threshold Vov at which the overvoltage protection function is activated, assuming that the predetermined time is taken into account and based on the speed at which the input voltage rises.

[0123] The first voltage threshold Vth1 is a voltage value that is greater than the voltage range in which the rotary electric machine control device can operate rated and less than the overvoltage threshold Vov. The second voltage threshold Vth2 is equal to or less than the first voltage threshold Vth1 and has a hysteresis characteristic that prevents frequent mode transitions due to fluctuations in the detected value of the input voltage. These are the same as in the first embodiment.

[0124] A torque command value Trq* is input from a higher-level system (not shown) to the current command generator 93. Based on this torque command value Trq*, the current command generator 93 generates a d-axis current command value Id* and a q-axis current command value Iq*.

[0125] The voltage command generation unit 95 then calculates the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* by performing current feedback calculations from the d-axis current command value Id*, the q-axis current command value Iq*, and the d-axis current detection value Id and the q-axis current detection value Iq. Specifically, for example, the voltage command generation unit 95 is configured to calculate the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* so that a current deviation ΔId, which is the deviation between the d-axis current command value Id* and the d-axis current detection value Id, and a current deviation ΔIq, which is the deviation between the q-axis current command value Iq* and the q-axis current detection value Iq, each converge to "0" (ΔId and ΔIq are not shown).

[0126] The voltage command limiting unit 92C receives the effective current value Irms, a judgment value S1 that is the output of the judgment unit 91C, and the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* from the voltage command generating unit 95. If the judgment value S1 is Lo, the voltage command limiting unit 92C generates the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* as limited d-axis voltage command values ​​Vdg* and limited q-axis voltage command values ​​Vqg* without limiting them. If the judgment value S1 is Hi, the voltage command limiting unit 92C changes the shutoff flag S2 to be output from Lo to Hi (this is called a first limiting process).

[0127] In the first limiting process, the upper limit of the d-axis voltage command value Vdc may be set by being limited by a first d-axis voltage limit value Vd_mx1, and the upper limit of the q-axis voltage command value Vqc may be set by being limited by a first q-axis voltage limit value Vq_mx1 (the first d-axis voltage limit value Vd_mx1 and the first q-axis voltage limit value Vq_mx1 are not shown).

[0128] Furthermore, if the judgment value S1 is Hi and the effective current value Irms is below the switching current value Ij after the first limiting process is performed, the shutoff flag S2 is switched to Lo, and the upper limit values ​​of the input d-axis voltage command value Vdc* and q-axis voltage command value Vqc* are set to second d-axis voltage limit values ​​Vd_mx2 and second q-axis voltage limit values ​​Vq_mx2 to generate the limited d-axis voltage command value Vdg* and the limited q-axis voltage command value Vqg* (this is called the second limiting process).

[0129] Regarding the specific method of generating the post-limitation d-axis voltage command value Vdg* and post-limitation q-axis voltage command value Vqg*, first, let us assume that the current value at which the switching element will not be damaged when stopped by the overvoltage protection function is Ic, and then the q-axis current command value Iq* is given priority for limiting. Then, Ic=√((Id* 2 +Iq* 2 ) / 3), the upper limit of the q-axis current is √(3×Ic 2 -Id* 2 ), the upper limit of the d-axis current is Ic=√((Id* 2+0) / 3), it is √3×Ic (where the upper limit value is the upper limit value for the absolute values ​​of the input d-axis current command value Id* and q-axis current command value Iq*).

[0130] Furthermore, since the voltage equation in the dq coordinate system is the following equation, the upper limits of the d-axis current and the q-axis current can be substituted into the d-axis current detection value Id and the q-axis current detection value Iq in equations (1) and (2) to obtain the upper limits of the limited d-axis voltage command value Vdg* and the limited q-axis voltage command value Vqg*. These are called second voltage limit values. A more detailed configuration of the voltage command limiting unit 92C will be described later. Note that R represents resistance, Ld represents d-axis inductance, Lq represents q-axis inductance, Φm represents magnet magnetic flux, and ω represents angular velocity.

[0131]

number

[0132]

number

[0133] Shutdown flag S2 is input to shutdown unit 901 from voltage command limiting unit 92C, and if shutdown flag S2 is Lo, the PWM signal generated by PWM signal generating unit 98 is used as the PWM signal output from the overvoltage protection unit as is. If shutdown flag S2 is Hi, all PWM signals to be output are set to Lo in order to turn off all switching elements. In FIG. 12, the PWM signals that pass through shutdown unit 901 are shown as PWM signal UH_D, PWM signal UL_D, PWM signal VH_D, PWM signal VL_D, PWM signal WH_D, and PWM signal Wl_D. These signals are transmitted to drive circuit 27, and switching elements 51 to 56 are driven.

[0134] Here, a feature of the rotating electric machine control device according to embodiment 3 is that a judgment unit 91C judges whether the phase current should be limited based on the value of the input voltage Vpn and its rate of change, and if the judgment unit 91C judges that the phase current should be limited, a first limiting process is performed in which the voltage command limiting unit 92C sets the cutoff flag S2 to Hi and turns off all switching elements.

[0135] Here, the first d-axis voltage limit value Vd_mx1 that limits the d-axis voltage command value Vdc and the first q-axis voltage limit value Vq_mx1 that limits the q-axis voltage command value Vqc are not calculated. Furthermore, when the effective current value Irms is lower than the switching current value Ij, a second limiting process is performed in which the upper limits of the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* are set to second voltage limit values.

[0136] <Current limiter operation> The operation of the voltage command limiting unit 92C, which is a feature of the rotating electric machine control device 300 according to the third embodiment, will be described below with reference to Fig. 13. Fig. 13 is also referred to as a state chart diagram showing the operation of the voltage command limiting unit 92C. When the mode in which the rotating electric machine control device is performing normal operation is a normal operation mode 921C and the determination unit 91C determines that the current should be limited and the determination value S1 becomes Hi, the process proceeds to first limiting processing 922C.

[0137] Then, in the first limiting process 922C, the cutoff flag S2, which is an output signal of the voltage command limiting unit 92C, is set to Hi. Furthermore, if the effective current value Irms is lower than the switching current value Ij, the process proceeds from the first limiting process 922C to second limiting process 923C. In the second limiting process 923C, the cutoff flag S2 is set to Lo, and the upper limits of the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* are set to the second voltage limit value, thereby outputting the limited d-axis voltage command value Vdg* and the limited q-axis voltage command value Vqg*.

[0138] When the input voltage Vpn becomes equal to or less than the second voltage threshold Vth2, the judgment value S1 output from the judgment unit 91C becomes Lo, and the operation mode transitions from the first limiting process 922C or the second limiting process 923C to the normal operation mode 921C. In the normal operation mode 921C, the shutoff flag S2 is set to Lo, the settings of the upper limit values ​​of the limited d-axis voltage command value Vdg* and the limited q-axis voltage command value Vqg* are released, and the rotating electrical machine control device performs normal operation.

[0139] <Determining the Second Voltage Limit Value> The second voltage limit value in the second limiting process 923C is a value that results in a current that is equal to or less than the overvoltage withstand current Iov_mx, which is a current value that will not damage the switching elements 51 to 56 when the switching elements are turned off in the overvoltage protection unit 99, which is an overvoltage protection function. The second voltage limit value is determined as a second d-axis voltage limit value Vd_mx2 and a second q-axis voltage limit value Vq_mx2. That is, the second d-axis voltage limit value Vd_mx2 and the second q-axis voltage limit value Vq_mx2 are values ​​derived using a process of calculating the d-axis voltage command value and the q-axis voltage command value from the current command value so that the current is equal to or less than the overvoltage withstand current Iov_mx, which will not damage the switching elements when the switching elements are turned off during execution of overvoltage protection.

[0140] <Determining the First Voltage Limit Value> The first voltage limit value is a value that can limit the phase current to the overvoltage withstand current Iov_mx, which is a current value at which the switching elements 51 to 56 do not fail, during the worst case scenario in which the input voltage rises sharply, from the time when the input voltage Vpn exceeds the first voltage threshold Vth1 and the judgment unit 91C judges that the phase current should be limited, until the overvoltage protection unit 99 turns off the switching elements.

[0141] <Comparison between the technology of the comparative example and the third embodiment> Next, the effect of setting an upper limit value of a command value by voltage command limiting unit 92C based on the determination by determining unit 91C, which is a feature of the third embodiment, will be described. The problem with the technology according to the comparative example used to describe the effect is the same as the explanation of the operation performed in the first embodiment using Fig. 5. If the current is limited assuming the worst case scenario of a load dump during regenerative operation in Fig. 5A, a problem occurs in that if the operation shown in Fig. 5B continues, the current must be excessively limited during operation.

[0142] Next, a case where the first limiting process and the second limiting process are performed by the voltage command limiting unit 92C based on the determination of the determining unit 91C, which is a feature of the rotating electric machine control device 300 according to the third embodiment, will be described with reference to Figures 14A and 14B. Figure 14A is a first time chart showing the behavior of the rotating electric machine control device 300 according to the third embodiment when the voltage increases. Figure 14B is a second time chart showing the behavior of the rotating electric machine control device according to the third embodiment when the voltage increases.

[0143] 14A shows the time waveforms of the input voltage Vnp and the phase current effective value Irms when overvoltage protection is activated in the worst case scenario of a steep input voltage rise, while FIG. 14B shows the waveforms when the input voltage Vpn exceeds the first voltage threshold Vth1 but does not reach the overvoltage threshold Vov, and the operation of the rotating electrical machine control device 300 continues.

[0144] 14A, the input voltage Vpn rises sharply, the effective current Irms drops rapidly from time t1 when the input voltage Vpn exceeds the first voltage threshold Vth1. At time tov when the overvoltage protection is activated, the effective current Irms drops to or below the overvoltage withstand current Iov_mx, which is the current value at which the switching element does not break down.

[0145] First, when the input voltage Vpn exceeds the first voltage threshold Vth1 and the input voltage rises by a predetermined voltage value (D1) or more within a predetermined time (dV / dt≧D1), the determination value S1 of the determination unit 91B becomes Hi. As a result, the voltage command limiting unit 92C transitions to first limiting processing 922C, and the shutoff flag S2 becomes Hi (the predetermined voltage D1 is not shown).

[0146] After that, because the effective current value Irms exceeds the switching current value Ij, the shutdown flag S2 becomes Hi, and all switching elements are turned off in the shutdown unit 901. This achieves a rapid reduction in the current value. As a result, the current value is reduced sufficiently until, at time tov, the input voltage Vpn exceeds the overvoltage threshold Vov and the switching elements are turned off due to overvoltage protection operation. This makes it possible to suppress surge voltages and prevent breakdown of the switching elements. At this time, the target current is shown by a solid line as the first current command value Ic1 (Ic1 = 0 Arms). After time tov, the current command value becomes the overvoltage target current Iov (current 0 Arms), also shown by a solid line.

[0147] 14A shows an example in which all switching elements are turned off (shut off) after time t1, and the effective current value Irms becomes equal to or less than the switching current value Ij before time tov. However, due to a control delay, the switching elements continue to be shut off until tov.

[0148] Next, refer to FIG. 14B, which shows a case where operation continues after the input voltage Vpn exceeds the first voltage threshold Vth1. First, at time t1, the effective current value Irms decreases sharply, as in FIG. 14A. This series of events is the same as in FIG. 14A. After that, the input voltage Vpn does not reach the overvoltage threshold Vov, and the operation of the rotating electrical machine control device 300 continues.

[0149] At time t2, the actual RMS current value Irms increases. It is determined that the RMS current value Irms is lower than the switching current value Ij, and the voltage command limiting unit 92C proceeds to the second limiting process 923C. At this time, the shutoff flag S2 becomes Lo, the shutoff unit 901 cancels the off state of the switching elements, and the upper limits of the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* are set to the second control upper limit values ​​(Vd_mx2, Vq_mx2), and operation is realized. This allows the upper limit values ​​of the command values ​​of the rotating electrical machine control device 300 to be set appropriately, allowing operation without excessively limiting the current.

[0150] At this time, the virtual target current limited by the second d-axis voltage limit value Vd_mx2 and the second q-axis voltage limit value Vq_mx2 is indicated by Ic2. In the technology of the comparative example shown in Fig. 5B, the current is limited excessively because it is limited according to the input voltage Vpn, whereas in the third embodiment, the current is limited using not only the input voltage Vpn but also the rate of increase of the input voltage Vpn and information on the current detection value.

[0151] Then, after the switching element is turned off in the first limiting process and the current value falls below the switching current value Ij, the command upper limit value is set to the second control upper limit value in the second limiting process, thereby preventing breakdown of the switching element by reducing the current when operation is stopped due to overvoltage protection and suppressing voltage surges, and allowing the rotating electrical machine control device 300 to operate without excessively limiting its output when operation continues.

[0152] 14B shows an example in which the effective current value Irms is equal to or less than the switching current value Ij before time t2, but the second limiting process is performed at time t2 due to a delay in control.

[0153] <Effects when the third embodiment is applied> The determination unit 91C according to the third embodiment determines that the phase current should be limited when the input voltage Vpn exceeds the first voltage threshold Vth1 and rises by a predetermined voltage value or more for a predetermined time. In this way, by observing the rate of rise of the input voltage Vpn in addition to the value of the input voltage Vpn detected by the voltage detection unit, the rotating electrical machine control device 300 can be operated without needlessly limiting the current.

[0154] Furthermore, when determination unit 91C determines that the current should be limited, first limiting processing 922C of voltage command limiting unit 92C sets the shutoff flag to Hi, and the current can be rapidly reduced by shutting off the switching element by shutoff unit 901. This allows the current to be reduced quickly, so that even if the time from when the input voltage rises to or exceeds the rated voltage until it reaches the overvoltage threshold Vov is extremely short, it is possible to reliably prevent a failure when the switching element is turned off during overvoltage protection.

[0155] Furthermore, the voltage command limiting unit 92C limits the phase current by restricting the upper limits of the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc*. In this way, by restricting the voltage command value with a short control cycle in the control system of the rotating electrical machine control device, when the determining unit 91C determines that the current should be limited, the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* can be quickly limited to instantaneously limit the current. This allows instantaneous adjustment to an appropriate output, allowing constant operation at the maximum possible output.

[0156] Furthermore, in the third embodiment, the switching element is turned off by the first limiting process. However, if an upper limit value is set by the first limiting process as in the first embodiment, the current can be limited instantaneously. Therefore, even if the time from when the input voltage rises to or exceeds the rated voltage until it reaches the overvoltage threshold Vov is short, the phase current can be quickly suppressed when the switching element is turned off due to overvoltage protection, and breakdown of the switching element can be prevented.

[0157] As described above, the rotating electric machine control device 300 of the third embodiment performs a first limiting process to turn off the switching elements when the input voltage Vpn exceeds the first voltage threshold Vth1 and when the input voltage Vpn increases by a predetermined voltage value or more within a predetermined time, and performs a second limiting process to set the upper limits of the d-axis voltage command value Vdc* and the q-axis voltage command value Vqc* to the second control upper limit value when the effective current value Irms falls below the switching current value Ij. This reduces the current when the switching elements are turned off due to overvoltage protection, suppresses voltage surges, and prevents breakdown of the switching elements, while allowing the rotating electric machine control device 300 to operate without excessively limiting its output during continuous operation.

[0158] <Additional information> In the above embodiment, the current detection value detected by the phase current detection unit 26 is converted into an effective value, and the current effective value Irms is used in the current limiting unit. However, the current value is not limited to this, and the peak value of the current detection value, etc. may also be used.

[0159] Furthermore, in the above embodiment, the upper limit of the command value is limited, but since it is sufficient to reduce or limit the current, it is also possible to adopt a method of reducing the command value by multiplying the command value by a predetermined factor, correcting the command value, and switching it, etc. Note that, in the above embodiment, the first torque limit value, second torque limit value, first current limit value, second current limit value, first voltage limit value, and second voltage limit value are set to values ​​that will not destroy the switching elements when the motor is stopped due to overheat protection, but they may also be set in combination with other constraints such as the temperature of the switching elements and the requirements of the rotating electrical machine control device.

[0160] In the first limiting process of the above embodiment, the upper limit of the control command value is set to the first torque limit value, the first current limit value, or the first voltage limit value, so that the current is kept below the overvoltage withstand current Iov_mx, which is the current value at which the switching element will not be destroyed during overheat protection. However, in addition to this, the current reduction rate may be increased by, for example, changing the control parameters of the voltage command generating unit that performs current feedback calculation to improve control responsiveness. This allows the current to be reduced quickly, preventing failure when the switching element is turned off during overvoltage protection, even if the time between the input voltage rising above the rated voltage and reaching the overvoltage threshold Vov is extremely short.

[0161] Although the rotating electric machine control device according to the above embodiment has been described assuming an inverter that converts DC power to AC power, the type of rotating electric machine control device is not limited to this, and may be any rotating electric machine control device that includes a switching element and converts the form of power output. For example, it may be an AC / DC converter (Alternate Current / Direct Current Converter) that converts AC power to DC power.

[0162] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are contemplated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0163] Various aspects of the present disclosure are summarized below as appendices.

[0164] (Appendix 1) a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between a positive electrode and a negative electrode of the power conversion circuit; a phase current detection sensor that detects a phase current flowing between the external connection point of the power conversion circuit and the rotating electric machine; and a control unit that controls on / off of the switching elements based on a current command value calculated from a torque command value received from an external source, and determines whether or not the torque command value should be limited based on the voltage detected by the voltage sensor, and when it is determined that the torque command value should be limited, executes first limiting processing by torque command value limiting means to set the torque command value to a first torque limit value or less if the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current, and when it is determined that the torque command value should be limited, executes second limiting processing by the torque command value limiting means to set the torque command value to a second torque limit value or less that is greater than the first torque limit value if the current detected by the phase current detection sensor is smaller than the switching current. (Appendix 2) a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between a positive electrode and a negative electrode of the power conversion circuit; a phase current detection sensor that detects a phase current flowing between the external connection point of the power conversion circuit and the rotating electric machine; and a control unit that controls on and off the switching elements based on a current command value calculated from a torque command value received from an external source, and determines whether or not the current command value should be limited based on a voltage detected by the voltage sensor, and when it is determined that the current command value should be limited, executes first limiting processing by current command value limiting means to set the current command value to a first current limit value or less if the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current, and when it is determined that the current command value should be limited, executes second limiting processing by the current command value limiting means to set the current command value to a second current limit value or less that is greater than the first current limit value if the current detected by the current detection sensor is smaller than the switching current. (Appendix 3) a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between a positive electrode and a negative electrode of the power conversion circuit; a phase current detection sensor that detects a phase current flowing between the external connection point of the power conversion circuit and the rotating electric machine; and a current command value calculated from an externally received torque command value, a d-axis voltage command value and a q-axis voltage command value calculated from the current command value, and controlling the on / off of the switching elements based on the d-axis voltage command value and the q-axis voltage command value; determining whether or not the d-axis voltage command value and the q-axis voltage command value should be limited based on the voltage detected by the voltage sensor; and limiting the d-axis voltage command value and the q-axis voltage command value by a voltage command value limiting means when it is determined that the d-axis voltage command value and the q-axis voltage command value should be limited and the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current. a control unit that executes first limiting processing to set a d-axis voltage command value and the q-axis voltage command value to be equal to or less than a first d-axis voltage limit value and a first q-axis voltage limit value, and when it is determined that the d-axis voltage command value and the q-axis voltage command value should be limited, if the current detected by the current detection sensor is smaller than the switching current, executes second limiting processing by the voltage command value limiting means to set the d-axis voltage command value and the q-axis voltage command value to be equal to or less than second d-axis voltage limit values ​​and second q-axis voltage limit values ​​that are larger than the first d-axis voltage limit value and the first q-axis voltage limit value. (Appendix 4) The control unit of the rotating electric machine control device according to any one of appendixes 1 to 3, wherein when the voltage detected by the voltage sensor is greater than a predetermined voltage threshold, the control unit executes the first limiting process if the current detected by the phase current detection sensor is greater than or equal to the switching current, and executes the second limiting process if the current detected by the phase current detection sensor is less than the switching current. (Appendix 5) The rotating electric machine control device according to any one of appendixes 1 to 3, wherein, when the voltage detected by the voltage sensor is greater than a predetermined voltage threshold and the current detected by the phase current detection sensor is greater than a predetermined current threshold, the control unit executes the first limiting process if the current detected by the phase current detection sensor is greater than or equal to the switching current, and executes the second limiting process if the current detected by the phase current detection sensor is less than the switching current. (Appendix 6) The control unit of the rotating electric machine control device according to any one of appendixes 1 to 3 is configured to execute the first limiting process if the current detected by the phase current detection sensor is equal to or greater than the switching current when the voltage detected by the voltage sensor is greater than a predetermined voltage threshold and the change in voltage per unit time detected by the voltage sensor is greater than a predetermined voltage change threshold, and to execute the second limiting process if the current detected by the phase current detection sensor is smaller than the switching current. (Appendix 7) 7. The rotary electric machine control device according to claim 1, wherein the control unit executes the first limiting process by turning off all of the switching elements in the first limiting process. (Appendix 8) The rotating electric machine control device according to any one of appendices 1 to 7, wherein the control unit executes the first limiting process or the second limiting process when the voltage detected by the voltage sensor is greater than a predetermined voltage threshold, and cancels the first limiting process and the second limiting process when the voltage detected by the voltage sensor is equal to or less than a second voltage threshold that is smaller than the voltage threshold. (Appendix 9) The control unit performs overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, by turning on the positive electrode side switching element and turning off the negative electrode side switching element, or by turning off the positive electrode side switching element and the negative electrode side switching element when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, and the second torque limit value is set to be equal to or less than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection. (Appendix 10) The control unit executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, by turning on the positive electrode side switching element and turning off the negative electrode side switching element, or by turning off the positive electrode side switching element and the negative electrode side switching element when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, and the second current limit value is set to a current value that is not greater than or equal to a current value that will not damage the switching element when the switching element is turned off during execution of overvoltage protection. (Appendix 11) The rotating electric machine control device according to Appendix 3, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the second d-axis voltage limit value and the second q-axis voltage limit value are set to be equal to or less than a current value at which the switching elements will not be damaged when the switching elements are turned off during execution of overvoltage protection. (Appendix 12) 10. The rotating electric machine control device according to any one of appendixes 1 to 9, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, performs overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the switching current is set to a current value that will not damage the switching element when the switching element is turned off during execution of overvoltage protection. (Appendix 13) The rotating electric machine control device according to Appendix 5, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the current threshold is set to a current value that does not damage the switching element when the switching element is turned off during execution of overvoltage protection. (Appendix 14) 10. The rotating electric machine control device according to claim 1 or 9, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, performs overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the first torque limit value is set to be equal to or less than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection. (Appendix 15) 11. The rotating electric machine control device according to claim 2 or 10, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the first current limit value is set to be equal to or less than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection. (Appendix 16) 12. The rotating electric machine control device according to claim 3 or 11, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the first d-axis voltage limit value and the first q-axis voltage limit value are set to be equal to or less than a current value at which the switching elements will not be damaged when the switching elements are turned off during execution of overvoltage protection. (Appendix 17) 5. The rotary electric machine control device according to claim 4, wherein the voltage threshold is set to a voltage higher than a voltage range in which the rotary electric machine control device can operate rated. (Appendix 18) 6. The rotary electric machine control device according to claim 5, wherein the voltage threshold is set to a voltage higher than a voltage range in which the rotary electric machine control device can operate at a rated level. (Appendix 19) 7. The rotary electric machine control device according to claim 6, wherein the voltage threshold is set to a voltage higher than a voltage range in which the rotary electric machine control device can operate at a rated level. (Appendix 20) 20. The rotating electrical machine control device according to any one of claims 1 to 19, wherein the switching elements use wide-gap semiconductors. [Explanation of symbols]

[0165] 2 AC bus, 10 rotating electric machine, 12 DC power supply, 20 power conversion unit, 24 voltage detection unit, 26 phase current detection unit, 51, 52, 53, 54, 55, 56 switching elements, 90, 90B, 90C control unit, 92 torque command limiting unit, 92B current command limiting unit, 92C voltage command limiting unit, 100, 200, 300 rotating electric machine control device

Claims

1. a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between a positive electrode and a negative electrode of the power conversion circuit; a phase current detection sensor that detects a phase current flowing between the external connection point of the power conversion circuit and the rotating electric machine; and a control unit that controls on / off of the switching elements based on a current command value calculated from a torque command value received from an external source, and determines whether or not the torque command value should be limited based on the voltage detected by the voltage sensor, and when it is determined that the torque command value should be limited, executes first limiting processing by torque command value limiting means to set the torque command value to a first torque limit value or less if the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current, and when it is determined that the torque command value should be limited, executes second limiting processing by the torque command value limiting means to set the torque command value to a second torque limit value or less that is greater than the first torque limit value if the current detected by the phase current detection sensor is smaller than the switching current.

2. a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between a positive electrode and a negative electrode of the power conversion circuit; a phase current detection sensor that detects a phase current flowing between the external connection point of the power conversion circuit and the rotating electric machine; and a control unit that controls on and off the switching elements based on a current command value calculated from a torque command value received from an external source, and determines whether or not the current command value should be limited based on a voltage detected by the voltage sensor, and when it is determined that the current command value should be limited, executes first limiting processing by current command value limiting means to set the current command value to a first current limit value or less if the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current, and when it is determined that the current command value should be limited, executes second limiting processing by the current command value limiting means to set the current command value to a second current limit value or less that is greater than the first current limit value if the current detected by the current detection sensor is smaller than the switching current.

3. a power conversion circuit having a leg provided with a positive-side switching element connected to a positive electrode of a DC power supply, a negative-side switching element connected to a negative electrode of the DC power supply, and an external connection point connecting the positive-side switching element and the negative-side switching element in series and connected to a rotating electric machine; a voltage sensor for detecting a voltage between a positive electrode and a negative electrode of the power conversion circuit; a phase current detection sensor that detects a phase current flowing between the external connection point of the power conversion circuit and the rotating electric machine; and a current command value calculated from an externally received torque command value, a d-axis voltage command value and a q-axis voltage command value calculated from the current command value, and controlling the on / off of the switching elements based on the d-axis voltage command value and the q-axis voltage command value; determining whether or not the d-axis voltage command value and the q-axis voltage command value should be limited based on the voltage detected by the voltage sensor; and limiting the d-axis voltage command value and the q-axis voltage command value by a voltage command value limiting means when it is determined that the d-axis voltage command value and the q-axis voltage command value should be limited and the current detected by the phase current detection sensor is equal to or greater than a predetermined switching current; a control unit that executes a first limiting process to set the d-axis voltage command value and the q-axis voltage command value to be equal to or less than a first d-axis voltage limit value and a first q-axis voltage limit value, and when it is determined that the d-axis voltage command value and the q-axis voltage command value should be limited, if the current detected by the current detection sensor is smaller than the switching current, executes a second limiting process by the voltage command value limiting means to set the d-axis voltage command value and the q-axis voltage command value to be equal to or less than second d-axis voltage limit values ​​and second q-axis voltage limit values ​​that are larger than the first d-axis voltage limit value and the first q-axis voltage limit value.

4. 4. A rotating electric machine control device according to claim 1, wherein the control unit executes the first limiting process when the voltage detected by the voltage sensor is greater than a predetermined voltage threshold and the current detected by the phase current detection sensor is greater than or equal to the switching current, and executes the second limiting process when the current detected by the phase current detection sensor is less than the switching current.

5. 4. A rotating electric machine control device according to claim 1, wherein the control unit executes the first limiting process when the voltage detected by the voltage sensor is greater than a predetermined voltage threshold and the current detected by the phase current detection sensor is greater than a predetermined current threshold, and executes the second limiting process when the current detected by the phase current detection sensor is greater than the switching current.

6. 4. A rotating electric machine control device according to claim 1, wherein the control unit executes the first limiting process if the current detected by the phase current detection sensor is equal to or greater than the switching current when the voltage detected by the voltage sensor is greater than a predetermined voltage threshold and the change in voltage per unit time detected by the voltage sensor is greater than a predetermined voltage change threshold, and executes the second limiting process if the current detected by the phase current detection sensor is smaller than the switching current.

7. The rotary electric machine control device according to claim 1 , wherein the control unit executes the first limiting process by turning off all of the switching elements in the first limiting process.

8. 4. A rotating electric machine control device as described in any one of claims 1 to 3, wherein the control unit executes the first limiting process or the second limiting process when the voltage detected by the voltage sensor is greater than a predetermined voltage threshold, and cancels the first limiting process and the second limiting process when the voltage detected by the voltage sensor is equal to or less than a second voltage threshold that is smaller than the voltage threshold.

9. 2. The rotating electric machine control device according to claim 1, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the second torque limit value is set to be equal to or less than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection.

10. 3. The rotating electric machine control device according to claim 2, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the second current limit value is set to a current value that is not greater than or equal to a current value that will not damage the switching element when the switching element is turned off during execution of overvoltage protection.

11. 4. The rotating electric machine control device according to claim 3, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the second d-axis voltage limit value and the second q-axis voltage limit value are set to be equal to or less than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection.

12. 4. The rotating electric machine control device according to claim 1, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, performs overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the switching current is set to a current value equal to or lower than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection.

13. 6. The rotating electric machine control device according to claim 5, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the current threshold is set to a current value that is not greater than or equal to a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection.

14. 2. The rotating electric machine control device according to claim 1, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the first torque limit value is set to be equal to or less than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection.

15. 3. The rotating electric machine control device according to claim 2, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the first current limit value is set to be equal to or less than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection.

16. 4. The rotating electric machine control device according to claim 3, wherein the control unit, when the voltage detected by the voltage sensor exceeds a predetermined overvoltage threshold, executes overvoltage protection by turning off the positive electrode side switching element and turning on the negative electrode side switching element, turning on the positive electrode side switching element and turning off the negative electrode side switching element, or turning off the positive electrode side switching element and the negative electrode side switching element, and the first d-axis voltage limit value and the first q-axis voltage limit value are set to be equal to or less than a current value at which the switching element will not be damaged when the switching element is turned off during execution of overvoltage protection.

17. The rotary electric machine control device according to claim 4 , wherein the voltage threshold value is set to a voltage higher than a voltage range in which the rotary electric machine control device can operate at a rated voltage.

18. The rotary electric machine control device according to claim 5 , wherein the voltage threshold value is set to a voltage higher than a voltage range in which the rotary electric machine control device can operate at a rated voltage.

19. The rotary electric machine control device according to claim 6 , wherein the voltage threshold value is set to a voltage higher than a voltage range in which the rotary electric machine control device can operate at a rated voltage.

20. The rotating electrical machine control device according to claim 1 , wherein the switching elements are made of wide-gap semiconductors.

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