JP2019134590A - Inverter controller - Google Patents

Abstract

To appropriately and actively perform short circuit control even when an off-failure occurs in one of switching elements of an inverter.SOLUTION: Active short circuit control for circulating current between an inverter and a rotary electric machine is executed by making all switching elements 3 of one element group including a switching element VL in which an off-failure occurs into an off state, and making all the switching elements 3 of the other element group into an on state of an upper stage side element group consisting of a plurality of upper stage side switching elements UH, VH, WH and a lower stage side element group consisting of a plurality of lower stage side switching elements UL, VL, WL.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an inverter control device that controls an inverter.

  Japanese Patent Application Laid-Open No. 2015-212533 exemplifies short-circuit control of an inverter in order to return current between the inverter and the rotating electrical machine when an abnormality occurs in the inverter or the rotating electrical machine, for example. Short-circuit control is also referred to as active short circuit control. For example, in the case of an inverter that converts power between three-phase AC and DC, all three-phase upper switching elements are turned on and all three-phase lower-stage sides are turned on. This is realized by turning off the switching elements, or by turning on the lower switching elements of all three phases and turning off the upper switching elements of all three phases.

  Here, when one of the switching elements controlled to be in an on state when active short circuit control is performed has caused an off-failure that is always fixed in an off state, the balance of the current flowing through each phase is lost, There is a possibility that an excessive current flows through a healthy switching element in which no failure has occurred. Some switching elements are configured as switching element modules having an overcurrent detection function and an overheat detection function. When such an excessive current flows, there is a possibility that it is detected as an overcurrent state or an overheated state. The detection result is transmitted to a control device that performs switching control of the inverter and a drive circuit that relays a switching control signal generated by the control device. As a result, the switching element may be forcibly controlled to be turned off by various fail-safe functions by the control device or the drive circuit.

  When all the switching elements constituting the inverter are turned off, a charging current flows by a voltage proportional to the rotation of the rotating electrical machine. When the inverter is connected to a DC power supply, an excessive current may flow through the DC power supply or the voltage of the DC power supply may be increased. In addition, when the inverter is not connected to a DC power source, a capacitor that is connected between the DC positive and negative electrodes of the inverter and stabilizes the DC voltage is generally charged. DC link voltage) may increase. In preparation for this, increasing the tolerance of the DC power supply and the capacitor leads to an increase in size and cost.

JP2015-211153A

  Therefore, it is desired to provide a technique for appropriately performing active short circuit control even when one of the switching elements of the inverter has an off failure.

The inverter control apparatus in view of the above is one aspect,
An inverter control device that controls an inverter connected to a DC power source and connected to an AC rotating electrical machine to convert power between DC and a plurality of phases of AC,
The inverter includes an upper stage side element group composed of a plurality of upper stage side switching elements connected to the positive electrode side of the DC power source, and a lower stage side element group composed of a plurality of lower stage side switching elements connected to the negative electrode side of the DC power source. And comprising a plurality of switching elements constituting
In an off-failed state in which one of the switching elements constituting the inverter is always in an off state,
Of the upper side element group and the lower stage side element group, all the switching elements of one element group including the off-failed switching element are turned off, and all the switching elements of the other element group are turned on. As a state, active short circuit control is performed to return current between the inverter and the rotating electrical machine.

  According to this configuration, even if one switching element is off-failed, active short circuit control is performed with one element group including the defective switching element turned off and the other element group turned on. Is done. For this reason, a switching element that is off-failed performs the same function as a non-failed state. As a result, even if one switching element has an off-failure, the current can be circulated using all phases of the plurality of phases, and an excessive current can be suppressed from flowing to a healthy switching element that has not failed. . Thus, according to this configuration, even if one of the switching elements of the inverter has an off failure, the active short circuit control can be appropriately performed.

  Further features and advantages of the inverter control device will become clear from the following description of embodiments described with reference to the drawings.

Schematic block diagram of vehicle drive device and vehicle drive control device Schematic circuit block diagram of the control system for rotating electrical machines Schematic circuit block diagram of the drive circuit Speed-torque map of rotating electrical machine Timing chart showing an example of saving control Flowchart showing an example of saving control Timing chart showing a comparative example when saving control is performed Waveform diagram showing an example of current and torque during 2-phase ASC Graph showing an example of rotational speed characteristics of transient peak current of AC current Waveform diagram showing an example of current and torque during normal control in an off-fault state

  Hereinafter, an embodiment of an inverter control device will be described based on the drawings. Hereinafter, the rotating electric machine will be exemplified as a driving force source for wheels in the vehicle. The schematic block diagram of FIG. 1 shows a vehicle drive control device 1 and a vehicle drive device 7 that is a control target thereof. As shown in FIG. 1, the vehicle drive device 7 includes power that connects an input member IN that is drivingly connected to an internal combustion engine (EG) 70 that is a driving force source of the vehicle and an output member OUT that is drivingly connected to wheels W. A drive force source engagement device (CL1) 75, a rotating electrical machine (MG) 80, and a transmission (TM) 90 are provided on the transmission path from the input member IN side.

  Here, “drive coupling” refers to a state in which two rotating elements are coupled so as to be able to transmit a driving force. Specifically, the “drive connection” is a state where the two rotating elements are connected so as to rotate integrally, or the two rotating elements are driven via one or more transmission members. It includes a state where force is connected to be transmitted. Examples of such a transmission member include various members that transmit rotation at the same speed or a variable speed, and include, for example, a shaft, a gear mechanism, a belt, a chain, and the like. Further, as such a transmission member, an engagement device that selectively transmits rotation and driving force, for example, a friction engagement device or a meshing engagement device may be included.

  The vehicle drive control device 1 controls each part of the vehicle drive device 7 described above. In the present embodiment, the vehicle drive control device 1 includes an inverter control device (INV-CTRL) 20 serving as a core of control of the rotating electrical machine 80 via an inverter (INV) 10 described later, and a core of control of the internal combustion engine 70. The internal combustion engine control device (EG-CTRL) 30, the transmission control device (TM-CTRL) 40 that is the core of the transmission 90, and the travel control device that supervises these control devices (20, 30, 40) ( DRV-CTRL) 50. The vehicle is also provided with a vehicle control device (VHL-CTRL) 100 which is a higher-level control device of the vehicle drive control device 1 and controls the entire vehicle.

  As shown in FIG. 1, the vehicle drive device 7 is a so-called parallel-type hybrid drive device including an internal combustion engine 70 and a rotating electrical machine 80 as a vehicle driving force source. The internal combustion engine 70 is a heat engine driven by fuel combustion, and for example, a gasoline engine or a diesel engine can be used. The internal combustion engine 70 and the rotary electric machine 80 are drivingly connected via a first engagement device 75, and a driving force is transmitted between the internal combustion engine 70 and the rotary electric machine 80 depending on the state of the first engagement device 75. It is possible to switch between a state and a state where no driving force is transmitted.

  The internal combustion engine 70 can be started by the rotation of the rotating electrical machine 80 when the first engagement device 75 is engaged. That is, the internal combustion engine 70 can be started by following the rotating electrical machine 80. On the other hand, the internal combustion engine 70 can also be started independently of the rotating electrical machine 80. When the first engagement device 75 is in the released state, the internal combustion engine 70 is started by the starter 71. In this embodiment, as the starter 71, a BAS (Belted Alternator Starter) suitable for so-called hot start such as restart from an idling stop is illustrated.

  The transmission 90 is a stepped automatic transmission having a plurality of shift stages with different gear ratios. For example, the transmission 90 includes a gear mechanism such as a planetary gear mechanism and a plurality of engagement devices (such as a clutch and a brake) in order to form a plurality of shift stages. An input shaft of the transmission 90 is drivingly connected to an output shaft (for example, a rotor shaft) of the rotating electrical machine 80. Here, a member in which the input shaft of the transmission 90 and the output shaft of the rotating electrical machine 80 are drivingly connected is referred to as an intermediate member M. The rotational speed and torque of the internal combustion engine 70 and the rotating electrical machine 80 are transmitted to the input shaft of the transmission 90.

  The transmission 90 shifts the rotational speed transmitted to the transmission 90 at the gear ratio of each shift stage, converts the torque transmitted to the transmission 90 and transmits it to the output shaft of the transmission 90. The output shaft of the transmission 90 is distributed to two axles via, for example, a differential gear (output differential gear device) and the like, and is transmitted to wheels W that are drivingly connected to the axles. Here, the gear ratio is the ratio of the rotational speed of the input shaft to the rotational speed of the output shaft when each gear stage is formed in the transmission 90 (= the rotational speed of the input shaft / the rotational speed of the output shaft). . Further, the torque obtained by multiplying the torque transmitted from the input shaft to the transmission 90 by the speed ratio corresponds to the torque transmitted to the output shaft.

  Here, the embodiment in which the stepped transmission mechanism is provided as the transmission 90 is illustrated, but the transmission 90 may be provided with a continuously variable transmission mechanism. For example, the transmission 90 may be provided with a CVT (Continuously Variable Transmission) that allows continuous shifting by passing a belt or chain through two pulleys (pulleys) and changing the diameter of the pulleys. Good.

  Further, the transmission 90 has a function capable of interrupting power transmission between the output member OUT and the rotating electrical machine 80 (or the intermediate member M). In the present embodiment, in order to facilitate understanding, a second engagement device 95 that switches between a state in which a driving force is transmitted between an input shaft and an output shaft of the transmission 90 and a state in which the transmission is interrupted is provided inside the transmission 90. The form with which it is equipped is illustrated. For example, when the transmission 90 is an automatic transmission, the second engagement device 95 may be configured using a planetary gear mechanism. In the planetary gear mechanism, the second engagement device 95 can be configured using one or both of the clutch and the brake. In FIG. 1, the second engagement device 95 is illustrated as a clutch, but the second engagement device 95 is not limited to the clutch, and may be configured using a brake.

  In FIG. 1, reference numeral 73 denotes a rotation sensor that detects the rotation speed of the internal combustion engine 70 or the input member IN, and reference numeral 93 denotes a rotation sensor that detects the rotation speed of the wheel W or the output member OUT. Although details will be described later, reference numeral 13 denotes a rotation sensor such as a resolver that detects the rotation (speed, direction, angular velocity, etc.) of the rotor of the rotating electrical machine 80, and reference numeral 12 detects a current flowing through the rotating electrical machine 80. AC current sensor. In FIG. 1, various oil pumps (electric and mechanical) are omitted.

  As described above, the rotary electric machine 80 is driven and controlled by the inverter control device 20 via the inverter 10. The block diagram of FIG. 2 schematically shows the rotating electrical machine drive device 2. Reference numeral 14 denotes a voltage sensor for detecting a DC side voltage (DC link voltage Vdc described later) of the inverter 10, and reference numeral 15 detects a current (battery current) flowing through a high voltage battery 11 (DC power supply) described later. It is a battery current sensor.

  The inverter 10 is connected to the high-voltage battery 11 via a contactor 9 described later, and is connected to an AC rotating electrical machine 80 to perform power conversion between DC and a plurality of phases of AC (here, three-phase AC). . The rotating electrical machine 80 as a vehicle driving force source is a rotating electrical machine that operates by a plurality of phases of alternating current (here, three-phase alternating current), and can function as both an electric motor and a generator. That is, the rotating electrical machine 80 converts the electric power from the high voltage battery 11 into power through the inverter 10 (power running). Alternatively, the rotating electrical machine 80 converts the rotational driving force transmitted from the internal combustion engine 70 and the wheels W into electric power, and charges the high-voltage battery 11 via the inverter 10 (regeneration).

  The high voltage battery 11 as a power source for driving the rotating electrical machine 80 is configured by, for example, a secondary battery (battery) such as a nickel metal hydride battery or a lithium ion battery, an electric double layer capacitor, or the like. The high voltage battery 11 is a high voltage, large capacity DC power supply for supplying power to the rotating electrical machine 80. The rated power supply voltage of the high voltage battery 11 is, for example, 200 to 400 [V].

  The DC side of the inverter 10 is provided with a smoothing capacitor (DC link capacitor 4) that smoothes the voltage between the positive electrode and the negative electrode (DC link voltage Vdc). The DC link capacitor 4 stabilizes the DC link voltage Vdc that fluctuates according to the fluctuation of the power consumption of the rotating electrical machine 80.

  As shown in FIG. 2, the contactor 9 is disposed between the high voltage battery 11 and the inverter 10, specifically, between the DC link capacitor 4 and the high voltage battery 11. The contactor 9 can disconnect the electrical connection between the rotating electrical machine drive device 2 and the high voltage battery 11. When the contactor 9 is in the connected state (closed state), the high-voltage battery 11 and the inverter 10 (and the rotating electrical machine 80) are electrically connected. When the contactor 9 is in the open state (opened state), the high-voltage battery 11 and the inverter 10 (and the rotating electrical machine). 80) is disconnected.

  In the present embodiment, as shown in FIG. 1, an air conditioner 61 for adjusting the temperature and humidity in the passenger compartment, an electric oil pump (not shown), and the like are driven between the high voltage battery 11 and the inverter 10. An auxiliary machine 60 such as a DC / DC converter (DC / DC) 62 for converting a direct current voltage may be provided. The auxiliary machine 60 is preferably arranged between the contactor 9 and the DC link capacitor 4.

  In the present embodiment, the contactor 9 is a mechanical relay that opens and closes based on a command from a vehicle control device 100 as a vehicle electrical control unit (vehicle ECU (Electronic Control Unit)) that is one of the highest-level control devices of the vehicle. For example, it is called a system main relay (SMR) or a main contactor (MC). The contactor 9 closes when the ignition switch or main switch of the vehicle is on (valid) and becomes conductive (connected), and contacts when the ignition switch or main switch is off (invalid). Opens to a non-conductive state (open state).

  As described above, the inverter 10 converts the DC power having the DC link voltage Vdc into a plurality of phases (n is a natural number, n-phase, here three-phase) AC power and supplies the AC power to the rotating electrical machine 80. AC power generated by 80 is converted into DC power and supplied to a DC power source. The inverter 10 includes a plurality of switching elements 3. The switching element 3 includes an IGBT (Insulated Gate Bipolar Transistor), a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a SiC-MOSFET (Silicon Carbide-Metal Oxide Semiconductor FET), a SiC-SIT (SiC-Static Induction Transistor), GaN. -It is preferable to apply a power semiconductor element capable of high-frequency operation such as a MOSFET (Gallium Nitride-MOSFET). FIG. 2 illustrates a form in which an IGBT is used as the switching element 3.

  As shown in FIG. 2, the inverter 10 is configured by a bridge circuit having a number of arms 3A corresponding to each of a plurality of phases (here, three phases). That is, as shown in FIG. 1, two switching elements 3 (an upper-side switching element 31 and a lower-stage switching element 32) are connected in series between the DC positive electrode side and the DC negative electrode side of the inverter 10 to form one arm. 3A is configured. In the case of a three-phase alternating current, this series circuit (one arm 3A) is connected in parallel with three lines (three phases). That is, a set of series circuits (arms 3 </ b> A) corresponds to each of the stator coils 8 corresponding to the U phase, V phase, and W phase of the rotating electrical machine 80. Each switching element 3 is provided with a free wheel diode 5 in parallel with the direction from the negative electrode to the positive electrode (the direction from the lower side to the upper side) as the forward direction.

  In the present embodiment, as shown in FIG. 3, the power module 30 includes at least one IGBT (switching element 3) and a free wheel diode 5 connected in parallel to the IGBT. Some power modules 30 have a function of detecting a current flowing through the switching element 3 and a function of detecting the temperature of the switching element 3. Such a function may output a detected value as a signal, or may output a notification signal when a predetermined threshold value is exceeded. In the present embodiment, as illustrated in FIG. 3, the temperature detection signal SC and the temperature detection signal TJ are output from the power module 30.

  As shown in FIGS. 1 and 2, the inverter 10 is controlled by an inverter control device 20. The inverter control device 20 is constructed using a logic circuit such as a microcomputer as a core member. For example, the inverter control device 20 performs current feedback control using a vector control method based on the target torque of the rotating electrical machine 80 provided from another control device or the like such as the vehicle control device 100, and the like via the inverter 10. The rotary electric machine 80 is controlled.

  The actual current (Iu, Iv, Iw: see FIG. 8 etc.) flowing through the stator coil 8 of each phase of the rotating electrical machine 80 is detected by the AC current sensor 12, and the inverter control device 20 acquires the detection result. Moreover, the magnetic pole position at each time of the rotor of the rotating electrical machine 80 is detected by the rotation sensor 13 such as a resolver, and the inverter control device 20 acquires the detection result. The inverter control device 20 performs current feedback control using the detection results of the alternating current sensor 12 and the rotation sensor 13. The inverter control device 20 is configured to have various functional units for current feedback control, and each functional unit is realized by cooperation of hardware such as a microcomputer and software (program). .

  The power supply voltage of the vehicle control device 100 and the inverter control device 20 is, for example, 5 [V] or 3.3 [V]. In addition to the high voltage battery 11, the vehicle is also mounted with a low voltage battery (not shown) that is insulated from the high voltage battery 11 and is a power source having a lower voltage than the high voltage battery 11. The power supply voltage of the low voltage battery is, for example, 12 to 24 [V]. The low voltage battery supplies power to the inverter control device 20 and the vehicle control device 100 via, for example, a regulator circuit that adjusts the voltage. The power supply voltage of the vehicle control device 100 and the inverter control device 20 is, for example, 5 [V] or 3.3 [V].

  As shown in FIG. 1, the control terminals (gate terminals in the case of IGBT and FET) of each switching element 3 constituting the inverter 10 are connected to the inverter control device 20 via the drive circuit 21 and are individually connected. Switching control is performed. The high voltage system circuit for driving the rotating electrical machine 80 and the low voltage system circuit such as the inverter control device 20 having a microcomputer as a core are greatly different in operating voltage (circuit power supply voltage). For this reason, the drive circuit 21 (DRV-CCT) that relays the drive signal (switching control signal) for each switching element 3 by increasing the drive capability (for example, the capability of operating the subsequent circuit such as voltage amplitude and output current) is relayed. Is provided.

  FIG. 3 shows an example of the drive circuit 21. The drive circuit 21 is configured using, for example, a circuit using an insulating element such as a photocoupler, a magnetic coupler, or a transformer, or a driver IC incorporating such an element. FIG. 3 shows a low voltage side drive circuit 23 connected to the so-called low voltage circuit side on the inverter control device 20 side, and a high voltage side drive circuit 24 connected to the so-called high voltage circuit side on the power module 30 side. The driver IC 22 provided with is illustrated. The low voltage side drive circuit 23 and the high voltage side drive circuit 24 are insulated. For example, the low voltage side drive circuit 23 is operated by a control circuit power supply V5 having a voltage of about 3.3 to 5 [V], and the high voltage side drive circuit 24 is operated by a drive power supply V15 having a voltage of about 15 to 20 [V]. To do.

  The inverter control device 20 is also operated by the control circuit power supply V5. The switching control signal SW generated and output by the inverter control device 20 is input to the low voltage side drive circuit 23 via a buffer for increasing output current, impedance conversion, etc., and via the high voltage side drive circuit 24. A gate signal GS is provided to each power module 30 (switching element 3). The drive circuit 21 also relays the temperature detection signal SC and the temperature detection signal TJ output from the power module 30 and provides them to the inverter control device 20 in reverse to the switching control signal SW. The drive circuit 21 itself also has an abnormality detection function such as monitoring the voltage of the drive power supply V15. In the present embodiment, an example in which the warning signal ALM is output to the inverter control device 20 when the temperature detection signal SC or the temperature detection signal TJ indicates abnormality or when the drive circuit 21 detects abnormality is illustrated. ing.

  In the inverter control device 20, for example, when the voltage sensor 14 that detects the DC link voltage Vdc detects an overvoltage, or the battery current sensor 15 that detects the current input to and output from the high voltage battery detects the overcurrent. For example, it is preferable that an abnormal signal be input. FIG. 3 illustrates a form in which the overvoltage detection signal OV output when the voltage sensor 14 detects an overvoltage is provided to the inverter control device 20. In the present embodiment, the overvoltage detection signal OV is a negative logic signal, and the normal logic level is high. The overvoltage detection signal OV is also connected to a control terminal of a tristate buffer that relays the switching control signal SW to the low voltage side drive circuit 23. In the present embodiment, when an overvoltage occurs, the logic level of the overvoltage detection signal OV becomes a low state, and the switching control signal SW is cut off so that all the switching elements 3 of the inverter 10 can be turned off. Yes. Incidentally, illustration of a pull-up resistor or a pull-down resistor for determining a logic level of a signal input to the low-voltage side drive circuit 23 at the time of interruption is omitted.

  Further, the drive circuit 21 has an enable terminal EN (negative logic), and when the signal input to the enable terminal EN is not valid (at a high level), the switching control signal SW is cut off, A low level gate signal GS is output. In the present embodiment, an example in which the enable terminal EN is fixed at a low level is illustrated, but a signal indicating a failure or abnormality may be connected in order to quickly invalidate the gate signal GS. Further, the drive circuit 21 is concerned with the state of the switching control signal SW when outputting the warning signal ALM, or when the temperature detection signal SC or the temperature detection signal TJ is input in a state indicating abnormality. Alternatively, the gate signal GS may be output at a low level.

As described above, in the present embodiment, current feedback control using the current vector control method in the biaxial orthogonal vector space (orthogonal vector coordinate system) that rotates in synchronization with the rotation of the rotating electrical machine 80 is performed to perform the rotating electrical machine. 80 is controlled. In the current vector control method, for example, a d-axis (field current axis, field axis) along the direction of the field magnetic flux by a permanent magnet, and a q-axis that is electrically advanced by π / 2 with respect to the d-axis ( Current feedback control is performed in a two-axis orthogonal vector coordinate system (dq axis vector coordinate system) with respect to the drive current axis and the drive axis. The inverter control device 20 determines the torque command T ^* based on the target torque of the rotating electrical machine 80 to be controlled, and determines the d-axis current command Id ^* and the q-axis current command Iq ^* .

The inverter control device 20 calculates the deviation between these current commands (Id ^* , Iq ^* ) and the actual currents (Iu, Iv, Iw) flowing through the U-phase, V-phase, and W-phase coils of the rotating electrical machine 80. The proportional integral control calculation (PI control calculation) and proportional integral differential control calculation (PID control calculation) are performed to finally determine a three-phase voltage command. A switching control signal is generated based on this voltage command. Mutual coordinate conversion between the actual three-phase coordinate system of the rotating electrical machine 80 and the biaxial orthogonal vector coordinate system is performed based on the magnetic pole position θ detected by the rotation sensor 13. The rotational speed ω (angular speed or rpm (Revolutions per Minute)) of the rotating electrical machine 80 is derived from the detection result of the rotation sensor 13.

  By the way, as described above, when various abnormalities such as the inverter 10 are detected, the vehicle drive control device 1 including the inverter control device 20 performs so-called fail-safe control. The vehicle drive control device 1 changes the transmission state of the driving force by the first engagement device 75 and the second engagement device 95 as the failsafe control, or changes the control method of the switching element 3 of the inverter 10. To do. Here, the fail safe control in which the inverter control device 20 changes the control method of the switching element 3 of the inverter 10 will be described.

  For example, shutdown control (SDN) is known as fail-safe control with the inverter 10 as a control target. The shutdown control is control for changing the switching control signal SW to all the switching elements 3 constituting the inverter 10 to an inactive state so that the inverter 10 is turned off. At this time, if the rotor of the rotating electrical machine 80 continues to rotate at a relatively high speed due to inertia, a large counter electromotive force is generated. The electric power generated by the rotation of the rotor is rectified through the free wheel diode 5 and charges the high voltage battery 11 when the contactor 9 is in the closed state. If the absolute value of the current (battery current) for charging the high-voltage battery 11 greatly increases and the battery current exceeds the rated current of the high-voltage battery 11, the high-voltage battery 11 is consumed. If the rated value of the high voltage battery 11 is increased so as to withstand a large battery current, there is a possibility that the scale and cost will increase.

  On the other hand, when the contactor 9 is in the open state, the inflow of current to the high voltage battery 11 is blocked. The current blocked from flowing into the high voltage battery 11 charges the DC link capacitor 4 and increases the DC link voltage Vdc. It is not preferable that the DC link voltage Vdc exceeds the rated voltage (absolute maximum rating) of the inverter 10 (switching element 3) or the DC link capacitor 4. Increasing these rated values to allow high voltages can lead to increased scale and cost. In addition, as shown in FIG. 1, when the DC link voltage Vdc is also applied to the auxiliary equipment 60 such as the air conditioner 61 and the DC / DC converter 62, the same applies to the auxiliary equipment 60. I can say that.

  Active fail circuit control (ASC) is also known as fail-safe control for controlling the inverter 10 in addition to shutdown control. In the active short circuit control, either one of the upper switching element 31 of all the arms 3A of the plurality of phases or the lower switching element 32 of all the arms of the plurality of phases is turned on, and the other side is turned off. In this control, current flows back between 80 and the inverter 10. The case where the upper switching elements 31 of the arms 3A of all the plural phases are turned on and the lower switching elements 32 of the arms 3A of all the plural phases are turned off is referred to as upper active short circuit control (HASC). A case where the lower switching elements 32 of all the arms 3A of the plurality of phases are turned on and the upper switching elements 31 of the arms 3A of the plurality of phases are turned off is referred to as lower active short circuit control (LASC).

  In the active short circuit control, the DC link voltage Vdc is not rapidly increased and the charging current of the high voltage battery 11 is not rapidly increased. However, when the short circuit current of the rotating electrical machine 80 is large, a large return current flows through the stator coil 8 and the inverter 10. If a large current continues to flow for a long time, the inverter 10 and the rotating electrical machine 80 may be consumed due to heat generated by the large current.

  Therefore, it is preferable that the fire-safe control is appropriately executed based on the situation of the vehicle drive device 7 including the inverter 10 and the rotating electrical machine 80 when an abnormality occurs, the characteristics of each control method, and the like. FIG. 4 shows a speed-torque map of the rotating electrical machine. For example, the inverter control device 20 performs active short circuit control when the rotation speed ω of the rotating electrical machine 80 is equal to or higher than a predetermined rotation speed ω1, and when the rotation speed ω is less than the predetermined rotation speed ω1, Shutdown control for turning off all the ten switching elements 3 is executed.

  Note that “A1”, “A2”, and “A3” in FIG. 4 indicate operation regions to which a method of detecting an off-fault described later is applied. The first operation region A1 where the absolute value of the torque and the rotational speed ω are low is a region where off-failure detection is not performed. The second operation region A2 in which the absolute value of the torque and the rotational speed ω are high is a region in which an off-failure is detected by overcurrent detection (described later with reference to FIGS. 8 and 9). The third operation region A3 is a region in which an off-failure is detected by an alternating current (Iu, Iv, Iw) (due to the mutual relationship between the three-phase currents). In the present embodiment, the maximum rotational speed in the first operation area A1 and the specified rotational speed ω1 are exemplified, but the maximum rotational speed and the specified rotational speed ω1 in the first operation area A1 are exemplified. May be different rotational speeds.

  In the present embodiment, a case where active short circuit control is selected as fail-safe control will be described as an example. As described above, in the case of an inverter that converts power between three-phase alternating current and direct current, the upper switching elements 31 of all three phases are turned on and the lower switching elements 32 of all three phases are turned off. In other words, active short circuit control is realized by turning on the lower switching elements 32 of all three phases and turning off the upper switching elements 31 of all three phases.

  Here, when one of the switching elements 3 controlled to be in an on state when active short circuit control is performed has an off fault that is always fixed in an off state, the balance of the current flowing through each phase is lost. There is a possibility that an excessive current flows through the healthy switching element 3 in which no failure has occurred. As described above, some switching elements 3 are configured as the power module 30 having an overcurrent detection function and an overheat detection function. When an excessive current flows, it is detected as an overcurrent state or an overheat state, and the switching element 3 is forcibly forced by various fail-safe functions by the inverter control device 20 and the drive circuit 21 as described above. May be controlled to the off state. As a result, there is a possibility that the DC link voltage Vdc suddenly increases or the battery current suddenly increases if it becomes equivalent to the state in which the shutdown control is executed despite the execution of the active short circuit control.

  Therefore, in the present embodiment, when one of the switching elements 3 constituting the inverter 10 is in an off-failure state in which the inverter 10 is always off, an upper-stage element group including a plurality of upper-stage switching elements 31 and a plurality of lower-stage switching In the lower stage side element group composed of the elements 32, all the switching elements 3 of one element group including the switching element 3 in which the off-failure has occurred are turned off, and all the switching elements 3 of the other element group are turned on. Perform short circuit control. Thereby, active short circuit control using the healthy switching element 3 that is not off-failed is executed.

  Although details will be described later, when the rotating electrical machine 80 is driven by normal control, the off-failed switching element 3 may be identified based on the alternating current (Iu, Iv, Iw). When the switching element 3 that has been turned off can be identified, the inverter control device 20 turns off all the switching elements 3 in one element group that includes the identified switching element 3, and the other element. Active short circuit control is executed with all the switching elements 3 in the group turned on.

  If the switching element 3 that has failed off before starting the active short circuit control cannot be identified, the target stage of the active short circuit control may be changed midway. In this case, for example, when the upper-stage active short circuit control is being executed and the alternating current is equal to or higher than the predetermined current, the control method is changed from the upper-stage active short-circuit control to the lower-stage active short-circuit control. When the alternating current is equal to or greater than the specified current Ith during execution of the lower active short circuit control, the control method is changed from the lower active short circuit control to the upper active short circuit control.

  When changing the control method between the upper side active short circuit control and the lower side active short circuit control, in order to reduce the current flowing through each switching element 3, a short shutdown is performed between the two controls. It is preferable to execute the control (described later with reference to # 7 to # 9 in FIG. 5).

  Hereinafter, with reference to the timing chart of FIG. 5 and the flowchart of FIG. 6, a specific embodiment for switching the target stage to be controlled to the ON state after starting the active short circuit control will be described. FIG. 5 illustrates an on / off state of each switching element 3 and a warning signal ALM output from the drive circuit 21. The ON / OFF state of each switching element 3 is substantially the same as the logic level of the gate signal GS (switching control signal SW) except when a failure has occurred. When the on / off state is different from the gate signal GS, the gate signal GS is indicated by a broken line. The on / off state of each switching element 3 is indicated by U, V, W indicating the distinction between the three phases, and H, L indicating the distinction between the upper side and the lower side. For example, “UH” indicates the upper switching element 31 of the U phase, and “WL” indicates the lower switching element 32 of the W phase. The warning signal ALM shows the same distinction at the end. For example, “ALMUH” indicates a warning signal ALM on the upper side of the U phase, and “ALMWL” indicates a warning signal ALM on the lower side of the W phase.

  In FIG. 5, until time t20, inverter 10 is controlled by normal control (for example, pulse width modulation control). At time t10, an OFF failure has occurred in the lower switching element 32 of the U phase. For this reason, in the first period T1 after time t10, an abnormality occurs in the operation of the inverter 10 (described later with reference to FIG. 10). For example, when this abnormality is detected, the inverter control device 20 starts executing fail-safe control at time t20. Here, lower-stage active short circuit control is started as fail-safe control. However, since an OFF failure has occurred in the U-phase lower switching element 32, as shown in FIG. 5, the U-phase lower switching element 32 is not turned on, and the OFF state continues.

  Therefore, the lower active short circuit control executed in the second period T2 is not a three-phase active short circuit state but a two-phase active short circuit state. FIG. 8 shows the alternating current (Iu, Iv, Iw), d-axis current Id, q-axis current Iq, and torque of the rotating electrical machine 80 of the inverter 10 in the two-phase active short circuit state. The symmetry of the reflux current is lost, the vibration of the q-axis current Iq is increased, and a large pulsation is generated in the torque. The peak value (absolute value) of the W-phase current Iw may be equal to or greater than the specified current Ith. For example, in the second operation region A2 in FIG. 4, the inverter control device 20 can detect an off-failure by such overcurrent detection.

  FIG. 9 shows an example of the rotational speed characteristic of the transient peak current of the alternating current. PK1 is a characteristic of the absolute value of the peak voltage in the two-phase active short circuit state during low temperature operation, and PK2 is a peak voltage characteristic in the three-phase active short circuit state during low temperature operation. PK3 is a characteristic of the absolute value of the peak voltage in the two-phase active short circuit state during high-temperature operation, and PK4 is a peak voltage characteristic in the three-phase active short circuit state during high-temperature operation. In both the low temperature operation and the high temperature operation, the absolute value of the peak voltage of the transient current is larger in the two-phase active short circuit state. Therefore, by appropriately setting the specified current Ith, the inverter control device 20 can determine that the inverter 10 is in the two-phase active short circuit state.

  The inverter control device 20 executes avoidance control (one-phase off-fault avoidance control) for eliminating such problems during execution of active short circuit control. As shown in the flowchart of FIG. 6, after the failsafe control is started, the inverter control device 20 acquires the control mode (CTRL_MOD) and stores the type of the acquired control mode in the register (REG1) (# 1). . Next, the inverter control device 20 determines whether the acquired control mode is active short circuit control, that is, one of upper-stage active short circuit control (HASC) and lower-stage active short circuit control (LASC). (# 2). When the control mode is not active short circuit control, it is not necessary to perform avoidance control, and the inverter control device 20 ends the process.

  When the control mode is active short circuit control, the inverter control device 20 acquires an error flag (ERR_FLG) (# 3). Subsequently, the inverter control device 20 determines whether or not the error flag is a single phase OFF failure (SPH_OFF: Single Phase OFF Fail) (# 4). If the error flag is not a one-phase off failure, it is not necessary to perform avoidance control, and the inverter control device 20 ends the process.

  If the error flag is a one-phase off failure, the inverter control device 20 next acquires the state of the warning signal ALM (# 5), and does the warning signal ALM indicate an abnormality (FAIL) of the power module 30 (PWMDL)? Judgment is made (# 6). When the warning signal ALM is not valid (when no abnormality is indicated) or when the warning signal ALM indicates an abnormality not caused by the power module 30, it is not necessary to perform avoidance control, and therefore the inverter control device 20 Ends the process.

  When the warning signal ALM indicates a failure of the power module 30, a one-phase off failure has occurred and an abnormality has occurred in the power module 30. For example, as shown in FIG. 5, an abnormality such as an overcurrent is detected in the V-phase lower switching element 32 at time t31, and the V-phase lower warning signal ALMVL becomes valid. Thereby, for example, at time t32, the drive circuit 21 automatically sets the logic level of the gate signal GS on the lower side of the V phase to low to turn off the lower side switching element 32 of the V phase. Even if the inverter control device 20 controls the logic level of the switching control signal SW on the V-phase lower stage side to the high state, the V-phase lower stage switching element 32 is turned off. For this reason, the third period T3 after time t32 is in a so-called single-phase active short circuit state.

  If this state continues, the current flowing through the W phase further increases. The timing chart of FIG. 7 shows a comparative example when avoidance control is not performed. As the current flowing in the W phase increases, an abnormality such as an overcurrent is detected in the lower switching element 32 of the W phase at time t41, and the W phase lower warning signal ALMWL becomes valid. Thereby, for example, at time t42, the drive circuit 21 automatically sets the logic level of the W-phase lower-stage gate signal GS to the low level and turns off the W-phase lower-stage switching element 32. Thereby, the period T40 after the time t42 is equivalent to the state in which the shutdown control is performed. When the rotational speed ω of the rotating electrical machine 80 is high, a large counter electromotive voltage is generated. Therefore, when the contactor 9 is closed, a large battery current may flow through the high-voltage battery 11, and the contactor 9 is opened. If the DC link capacitor 4 is charged, the DC link voltage Vdc may rise.

  In the present embodiment in which the avoidance control is executed, if it is determined in step # 6 that the warning signal ALM indicates an abnormality of the power module 30, the target stage of the active short circuit control is switched (described later in # 10 to # 10). # 12). As shown in FIG. 5, at time t40, the inverter control device 20 controls all the lower switching elements 32 that have been controlled to be in the on state so far to the off state, and has been controlled to be in the off state until now. All the switching elements 31 are controlled to be turned on. That is, the control method (target stage) is switched from lower-stage active short circuit control to upper-stage active short circuit control. In the fourth period T4, upper-stage active short circuit control is executed.

  By the way, in the U phase including the switching element 3 that is in the off-failure state, when the target stage of the active short circuit control is changed, the upper stage side switching element 31 of the upper stage side switching element 31 and the lower stage side switching element 32 that are both off. The element 31 is turned on. On the other hand, in the V-phase and W-phase that do not include the switching element 3 that is off-failed, the lower-stage switching element 32 is on before changing the target stage of active short circuit control, and after the change, the upper-stage switching element 31 is turned on. Here, it is assumed that the V-phase lower switching element 32 is switched before being turned off by the drive circuit 21. At this time, in the V phase and the W phase, when the control target stage is switched, both the upper stage switching element 31 and the lower stage switching element 32 become conductive, and the positive and negative electrodes of the inverter 10 are short-circuited. There is a possibility. For this reason, in this embodiment, when changing the control system of the active short circuit control, the inverter control device 20 executes the shutdown control for a short time to reduce the current flowing through each switching element 3 of the inverter 10. In the case where it is not necessary to reduce the current, the target stage of the active short circuit control may be switched without interposing the shutdown control. This shutdown control is omitted in the timing chart of FIG. 5, but will be described below with reference to the flowchart of FIG.

  As shown in FIG. 6, if it is determined in step # 6 that an abnormality has occurred in the power module 30, the inverter control device 20 sets the control mode to shutdown control (# 7). At the same time, the counter is activated (# 8, # 9). When the count value (CNT) reaches the shutdown count value (CNT_SDN), the shutdown control is terminated, the target stage is changed, and the active short circuit control is executed. In the present embodiment, it is determined whether the control mode acquired in step # 1 and stored in the register (REG1) is the lower active short circuit control (LASC) (# 10), and the lower active short circuit is determined. In the case of control, the other upper side active short circuit control (HASC) is set (# 11). If it is not the lower-stage active short circuit control, the lower-stage active short circuit control is set (# 12).

  In the form described above with reference to FIG. 5 and FIG. 6, after the active short circuit control is started, the switching element 3 that has been off-failed or the element group that includes the switching element 3 that has been off-failed is identified, and the active short circuit control is performed. An example of switching the target stage was shown. However, before starting the active short circuit control, the switching element 3 that is off-failed or the element group including the switching element 3 that is off-failed may be specified to start the active short circuit control. That is, the inverter control device 20 turns off all the switching elements 3 of one element group on the side including the specified switching element 3 and turns on all the switching elements 3 of the other element group to perform an active short circuit. Circuit control may be performed.

  The waveform diagram of FIG. 10 shows an example of current and torque during normal control in the off-failure state. As shown in FIG. 10, when one switching element 3 is off-failed, the symmetry of the three-phase alternating current is lost. By analyzing the mutual relationship among the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw, it is possible to determine the presence or absence of an off-failure and to identify the switching element 3 that is off-failed. For example, in the third operation region A3 in FIG. 4, the inverter control device 20 can detect an off-fault by analyzing the mutual relationship between such three-phase alternating currents.

For a technique for analyzing the mutual relationship between three-phase alternating currents, see, for example, the technical paper “AMS Mendes and AJ Marques,“ Voltage Source Inverter Fault Diagnosis in Variable Speed AC Drives, by the Average Current Park's Vector Approach ”, 0- 7803-5293-9 / 99, $ 10.00, 1999, IEEE ", etc., so that it is well known and detailed description thereof is omitted. Further, since no current flows through the switching element 3 that is off-failed, an increase in the temperature of the element is also suppressed. If the temperature of the switching element 3 is monitored, such as when the switching element 3 is configured as a power module including a temperature sensor or the like, the presence or absence of a failure of each switching element 3 is determined based on the temperature of each switching element 3 There are cases where it is possible. As shown in FIG. 10, the d-axis current Id and the q-axis current Iq also vibrate greatly when an off-failure occurs. The torque T also vibrates greatly with respect to the torque command T ^* . For this reason, it is also possible to determine whether or not there is an off-failure based on the dq-axis current and the torque T.

[Outline of Embodiment]
Hereafter, the outline | summary of the inverter control apparatus (20) demonstrated above is demonstrated easily.

An inverter control device (20) for controlling an inverter (10) connected to a DC power source (11) and connected to an AC rotating electrical machine (80) to convert electric power between DC and a plurality of phases of AC, As one aspect,
The inverter (10) is connected to an upper stage side element group composed of a plurality of upper stage side switching elements (31) connected to the positive electrode side of the DC power supply (11) and to the negative electrode side of the DC power supply (11). A plurality of lower switching elements (32) comprising a plurality of lower switching elements (32),
In an off-failed state in which one of the switching elements (3) constituting the inverter (10) is always off,
All of the switching elements (3) in one element group including the switching element (3) in which the off-fault is out of the upper element group and the lower element group are turned off, and all of the other element groups The switching element (3) is turned on, and active short circuit control is performed to return current between the inverter (10) and the rotating electrical machine (80).

  According to this configuration, even if one switching element (3) has an off failure, one element group including the defective switching element (3) is turned off, and the other element group is turned on. Active short circuit control is performed. For this reason, the switching element (3) that is off-failed performs the same function as the non-failed state. As a result, even if one switching element (3) has an off-failure, the current can be circulated using all phases of a plurality of phases, and an excessive current is generated in a healthy switching element (3) that has not failed. Can be prevented from flowing. As described above, according to this configuration, even if one of the switching elements (3) of the inverter (10) has an off-failure, active short circuit control can be appropriately performed.

  Further, the inverter control device (20) is configured to perform a plurality of the upper-side element groups as the active short circuit control when an abnormality of the inverter (10) is detected during the rotation of the rotating electrical machine (80). The lower stage side active short circuit control is executed to turn off all the upper stage side switching elements (31) and turn on all the plurality of lower stage side switching elements (32) of the lower stage side element group. During execution of the active short circuit control, when the alternating current is equal to or higher than a predetermined current (Ith) defined in advance, a plurality of the upper stage side switching elements of the upper stage side element group from the lower stage side active short circuit control. (31) is turned on, and a plurality of the lower-stage switching elements ( Changing the control method on the upper side active short circuit control to the OFF state all 2) is preferred.

  Further, the inverter control device (20) is configured to perform a plurality of the upper-side element groups as the active short circuit control when an abnormality of the inverter (10) is detected during the rotation of the rotating electrical machine (80). The upper stage side active short circuit control is performed to turn on all of the upper stage side switching elements (31) and turn off all of the plurality of lower stage side switching elements (32) of the lower stage side element group, and During execution of active short circuit control, when the alternating current is equal to or greater than a predetermined current (Ith) defined in advance, the upper stage side switching element of the upper stage side element group is changed from the upper stage side active short circuit control. All of (31) are turned off, and a plurality of the lower-stage switching elements ( It is preferable to change the control method on the lower side active short circuit control to the ON state all 2).

  The active short circuit control may be started without knowing that one switching element (3) has an off-failure or without knowing which switching element (3) has an off-failure. However, if the switching element (3) to be controlled to be in the on state has an off-failure, the path through which the return current flows decreases, so that the current flowing per phase increases. Therefore, the inverter control device (20) can determine the possibility that an off-failure has occurred based on the alternating current. When the active short circuit control has already been started, the inverter control device (20) can determine that the switching element (3) that is in the off state is included in the element group that is controlled to be in the on state at that time. . For example, if the alternating current is greater than or equal to the specified current (Ith) during execution of the lower-stage active short circuit control, it is determined that the lower-stage element group includes a switching element (3) that is off-failed. Can do. Further, when the AC current is equal to or higher than the specified current (Ith) during the execution of the upper stage side active short circuit control, it is determined that the upper stage side element group includes the switching element (3) that is off-failed. Can do.

  In accordance with this determination result, the inverter control device (10) switches off the failure by switching the target to be turned on in the active short circuit control between the upper element group and the lower element group. The element (3) can be controlled so as to perform the same function as a state in which no failure occurs. For example, when lower-stage active short circuit control is being executed, the target to be turned on is switched from the lower-stage element group to the upper-stage element group. Since the lower stage side element group including the switching element (3) having the off-failure is controlled to be in the off state, the switching element (3) having the off-failure performs the same function as that in the non-failing state. Further, when the upper-stage active short circuit control is executed, the target to be controlled to be turned on is switched from the upper-stage element group to the lower-stage element group. Since the upper stage side element group including the switching element (3) having the off-failure is controlled to be in the off state, the switching element (3) having the off-failure performs the same function as that in the non-failing state. Thus, according to these structures, even if one of the switching elements (3) of the inverter (10) has an off failure, the active short circuit control can be appropriately performed.

  When the inverter control device (20) changes the control method of the active short circuit control by switching the target to be turned on in the active short circuit control between the upper element group and the lower element group. It is preferable to execute shutdown control between the upper stage side active short circuit control and the lower stage side active short circuit control so as to turn off all the switching elements (3) of the inverter (10).

  In the active short circuit control, the inverter (10) and the rotating electrical machine (80) generate heat when the return current flows. Therefore, it is preferable to reduce the current flowing through each switching element 3 by the shutdown control.

  Moreover, as one aspect, the inverter control device (20) specifies the switching element (3) that has failed in the off-state, and includes all of one element group on the side including the specified switching element (3). It is preferable to execute the active short circuit control with the switching element (3) turned off and all the switching elements (3) of the other element group turned on.

  Even when the inverter (10) controls the inverter (10) by a normal control method such as pulse width modulation, the alternating current is disturbed if there is a switching element (3) that is off-faulted. Therefore, the inverter control device (20) can identify the failed switching element (3) based on, for example, the alternating current (Iu, Iv, Iw). Further, since no current flows through the switching element (3) that is off-failed and the temperature rise of the element is suppressed, the switching element (3) that is malfunctioning is identified based on the temperature of each switching element 3 Sometimes you can. The inverter control device (20) appropriately performs the active short circuit control by executing the active short circuit control so that the element group including the switching element (3) that is specified to be in a failure state is turned off. It can be performed.

  The inverter control device (20) executes the active short circuit control when the rotational speed (ω) of the rotating electrical machine (80) is equal to or higher than a predetermined rotational speed, and is less than the predetermined rotational speed. For this, it is preferable to execute shutdown control that turns off all the switching elements (3) of the inverter (10).

  The form of fail-safe control for the inverter (10) includes not only active short circuit control but also shutdown control. In the shutdown control, energy is regenerated on the DC side of the inverter (10) by the back electromotive force of the rotating electrical machine (80). The energy of the counter electromotive force increases as the kinetic energy of the rotating electrical machine (80) increases, that is, as the rotational speed (ω) of the rotating electrical machine (80) increases. If the back electromotive force energy is high, the circuit (DC power supply, capacitor, other equipment, etc.) connected to the DC side of the inverter (10) is likely to be affected, but if the back electromotive force energy is low. The risk is small. In the active short circuit control, a current flows through the inverter (10) for a longer time than the shutdown control. In the shutdown control, the current flowing through the inverter (10) can be quickly converged. Therefore, when the rotational speed (ω) of the rotating electrical machine (80) is less than the specified rotational speed and the back electromotive force is small, it is preferable to execute the shutdown control.

ω: Rotational speed ω1: Specified rotational speed 1: Vehicle drive control device 3: Switching element 10: Inverter 11: High voltage battery (DC power supply)
20: Inverter control device 31: Upper stage side switching element 32: Lower stage side switching element 80: Rotating electrical machine Ith: Specified current Iu: U-phase current (AC current)
Iv: V-phase current (alternating current)
Iw: W phase current (alternating current)
Vdc: DC link voltage

Claims (6)

An inverter control device that controls an inverter connected to a DC power source and connected to an AC rotating electrical machine to convert power between DC and a plurality of phases of AC,
The inverter includes an upper stage side element group composed of a plurality of upper stage side switching elements connected to the positive electrode side of the DC power source, and a lower stage side element group composed of a plurality of lower stage side switching elements connected to the negative electrode side of the DC power source. And comprising a plurality of switching elements constituting
In an off-failed state in which one of the switching elements constituting the inverter is always in an off state,
Of the upper side element group and the lower stage side element group, all the switching elements of one element group including the off-failed switching element are turned off, and all the switching elements of the other element group are turned on. An inverter control device that performs active short circuit control for returning current between the inverter and the rotating electrical machine as a state. When an abnormality of the inverter is detected during rotation of the rotating electrical machine,
As the active short circuit control, a lower active short circuit that turns off all of the plurality of upper switching elements of the upper element group and turns on all of the lower switching elements of the lower element group. Perform circuit control,
During execution of the lower-stage active short circuit control, when the alternating current is equal to or greater than a predetermined current, a plurality of the upper-stage switching elements of the upper-stage element group are controlled by the lower-stage active short circuit control. 2. The inverter control device according to claim 1, wherein the control method is changed to upper-stage active short circuit control in which all of the switches are turned on and all of the plurality of lower-stage switching elements of the lower-stage element group are turned off. When an abnormality of the inverter is detected during rotation of the rotating electrical machine,
As the active short circuit control, an upper active short circuit that turns on all of the plurality of upper switching elements of the upper element group and turns off all of the lower switching elements of the lower element group. Perform circuit control,
During execution of the upper-stage active short circuit control, when the alternating current is equal to or higher than a predetermined current, a plurality of the upper-stage switching elements of the upper-stage element group from the upper-stage active short circuit control. 2. The inverter control device according to claim 1, wherein the control method is changed to lower-stage active short circuit control in which all of the switches are turned off and all of the plurality of lower-stage switching elements of the lower-stage element group are turned on.   When changing the control method of the active short circuit control, a shutdown in which all the switching elements of the inverter are turned off between the upper active short circuit control and the lower active short circuit control. The inverter control device according to claim 2 or 3, which executes control.   The off-failed switching element is identified, all the switching elements of one element group on the side including the identified switching element are turned off, and all the switching elements of the other element group are turned on The inverter control device according to claim 1, wherein the active short circuit control is executed as follows. When the rotation speed of the rotating electrical machine is equal to or higher than a predetermined rotation speed, the active short circuit control is executed. When the rotation speed is less than the predetermined rotation speed, all the switching elements of the inverter are turned off. The inverter control device according to any one of claims 1 to 5, wherein shutdown control for setting the state is executed.

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