JP7259563B2 - Rotating electric machine control system - Google Patents

Description

The present invention relates to a rotary electric machine control system that drives and controls an AC rotary electric machine that is drivingly connected to wheels of a vehicle.

An example of the rotating electric machine control system as described above is disclosed in Japanese Patent Application Laid-Open No. 2005-73399 (Patent Document 1). Reference numerals shown in parentheses in the following description of the background art are those of Patent Document 1. The rotary electric machine control system described in Patent Document 1 includes a discharge circuit (60) for discharging a smoothing capacitor (15) connected in parallel to the DC side of an inverter (20). The discharge circuit (60) includes a discharge relay circuit (62) and a discharge resistor (65) connected in series between a power supply line (11) and an earth line (12), and the discharge relay circuit (62) is By conducting, a forced discharge path is formed between the power supply line (11) and the earth line (12) through the discharge resistor (65).

In the system described in Patent Document 1, the voltage on the power supply line (11) (in other words, the voltage on the DC side of the inverter (20)) is used as a power source to turn on the discharge relay circuit (62). It is possible to reliably discharge the charge accumulated in the smoothing capacitor (15) even when a problem such as an operation abnormality occurs in the control device (40) that controls the inverter (20). In addition, since the discharge relay circuit (62) is energized by using the voltage of the DC side of the inverter (20) as a power source, the discharge relay circuit (62) is automatically activated when the discharge of the smoothing capacitor (15) is completed. open to the public.

JP-A-2005-73399

By the way, while the rotating electrical machine is rotating, the capacitor may be charged by the counter electromotive force generated as the rotating electrical machine rotates. In the technique described in Patent Document 1, the discharge relay circuit is automatically opened when the discharge of the capacitor is completed, so if the rotating electric machine is rotating at this point, there is a risk that the capacitor will be charged again. There is By recharging the capacitor, the discharge relay circuit is energized again using the voltage on the DC side of the inverter as a power supply, and the capacitor can be discharged again. , the discharge and charge of the capacitor will be repeated. Therefore, it may take a relatively long time to achieve a state in which the voltage across the terminals of the capacitor is maintained at or below the target voltage.

Therefore, in a state where the electric rotating machine is rotating, the voltage between the terminals of the capacitor is maintained at a target voltage or less when the discharge control of the capacitor is executed using the power on the DC side of the inverter as the power source. Realization of a technology capable of shortening the time required for processing is desired.

A rotating electrical machine control system according to the present disclosure is a rotating electrical machine control system that drives and controls an alternating current rotating electrical machine that is drivingly connected to wheels of a vehicle, and converts power between direct current and alternating current to the rotating electrical machine. an inverter that supplies AC power; a control section that operates upon receiving the supply of power to control the inverter; a first power supply that supplies power to the DC side of the inverter; and supplies operating power to the control section. a second power supply; and a backup power supply circuit that generates operating power for the control unit by using power on the DC side of the inverter as a power source when supply of operating power from the second power supply to the control unit is stopped, The inverter includes an inverter circuit including a plurality of switching elements, a capacitor connected in parallel to the DC side of the inverter circuit, a discharge circuit including a discharge resistor connected in parallel to the capacitor, and a discharge circuit for discharging the discharge circuit. a switch that switches a resistance value between a first resistance value and a second resistance value that is greater than the first resistance value, and the control unit is configured such that the backup power supply circuit generates operating power for the control unit. in a state where the voltage across the terminals of the capacitor is equal to or higher than the first specified voltage, the discharge resistance value of the discharge circuit is set to the first resistance value. active short-circuit control for controlling a switch and controlling a plurality of the switching elements so that a current circulates between the inverter circuit and the rotating electric machine, and the voltage between the terminals of the capacitor is set to the first regulation; When the voltage is less than the voltage, the switch is controlled such that the discharge resistance value of the discharge circuit becomes the second resistance value, and the active short circuit control is executed.

In this configuration, when the control unit performs capacitor discharge control in a state where the backup power supply circuit is generating operating power for the control unit, that is, when the DC side power of the inverter is used as the power source, the capacitor discharge control is performed. when the voltage across the terminals of the capacitor is equal to or higher than the first specified voltage, the switch is controlled so that the discharge resistance value of the discharge circuit becomes the first resistance value, and active short circuit control is executed. . Here, since the first resistance value is smaller than the second resistance value, by switching the discharge resistance value of the discharge circuit to the first resistance value, the discharge speed of the capacitor by the discharge circuit can be increased, and the active short circuit can be prevented. By executing the circuit control, even when the rotating electric machine is rotating, it is possible to suppress an increase in the voltage between the terminals of the capacitor due to the back electromotive force generated as the rotating electric machine rotates. Therefore, the voltage across the terminals of the capacitor can be rapidly lowered to the first specified voltage.

In the above configuration, the control unit controls the switch so that the discharge resistance value of the discharge circuit becomes the second resistance value when the voltage between the terminals of the capacitor is less than the first specified voltage, and the active short circuit Execute circuit control. Therefore, even after the voltage between the terminals of the capacitor has decreased to the first specified voltage, the active short circuit control is continued to suppress the rise of the voltage between the terminals of the capacitor, and the discharge resistance value of the discharge circuit is reduced to the second resistor. By switching the value, it is possible to slow down the discharge rate of the capacitor by the discharge circuit and delay the point at which the voltage across the terminals of the capacitor drops to the lower limit of the voltage across the capacitor at which active short-circuit control can be performed. As a result, it is possible to secure a long period during which the active short circuit control is executed. The rotation speed of the rotary electric machine can be kept low at the time when the As a result, it is possible to prevent the capacitor from being recharged after the capacitor has been discharged, or, even if the capacitor is to be recharged, the amount of charge can be kept small.

Therefore, after the voltage across the terminals of the capacitor drops to the first specified voltage, it becomes possible to keep the voltage across the terminals of the capacitor low. As a result, by setting the first specified voltage in consideration of the target voltage ( For example, by setting the first specified voltage to a value equal to or lower than the target voltage, it is possible to shorten the time required to achieve a state in which the voltage across the terminals of the capacitor is maintained at or below the target voltage.

Further features and advantages of the rotating electrical machine control system will become clear from the following description of the embodiments described with reference to the drawings.

Block diagram schematically showing a configuration example of a rotating electric machine control system 1 is a block diagram schematically showing a configuration example of a vehicle drive system; FIG. FIG. 2 is a block diagram schematically showing a configuration example of a control unit; Circuit diagram showing a configuration example of a drive power supply circuit Flowchart showing an example of the functions of the control unit Block diagram schematically showing a configuration example of a backup power supply circuit Circuit diagram showing a configuration example of part of the backup power supply circuit Time chart showing an example of control behavior of discharge control according to the embodiment Time chart showing an example of control behavior of discharge control according to a comparative example Circuit diagrams of discharge circuits according to other embodiments

An embodiment of a rotating electric machine control system will be described with reference to the drawings. As shown in FIGS. 1 and 2, the rotating electrical machine control system 100 is a system that drives and controls an AC rotating electrical machine 80 that is drivingly connected to wheels W of a vehicle.

As an example is shown in FIG. 2 , the rotating electric machine 80 is provided in the vehicle driving device 300 as a driving force source for the wheels W. As shown in FIG. In the example shown in FIG. 2, the rotating electric machine 80 is drivingly connected to the wheels W of the vehicle via the differential gear device DF, and serves as a driving force source for the wheels W. As shown in FIG. As indicated by the phantom lines in FIG. 2, the power transmission path between the rotating electric machine 80 and the wheels W may be connected to other elements such as a transmission. Further, another power source, such as an internal combustion engine, may be connected upstream of the rotating electric machine 80 in the power transmission path (opposite to the wheels W). Unlike the example shown in FIG. 2, the rotary electric machine 80 is driven and connected to the wheels W without the differential gear device DF. A configuration in which the signal is transmitted only to W may also be used. In the present embodiment, the vehicle drive system 300 is in a state in which power is not transmitted (so-called neutral state), and the rotary electric machine 80 and the wheel W are always drivingly connected.

The rotary electric machine control system 100 drives and controls the AC rotary electric machine 80 drivingly connected to the wheels W of the vehicle in this way. As shown in FIG. 1 , the rotating electric machine control system 100 includes an inverter 20, a control unit 10 that operates by receiving electric power and controls the inverter 20, a first power supply 11, a second power supply 19, a backup a power supply circuit 4; The inverter 20 is connected to the first power supply 11 (DC power supply, high-voltage DC power supply) and to the rotary electric machine 80 to convert power between DC and multi-phase AC. That is, inverter 20 converts power between direct current and alternating current and supplies alternating current power to rotating electric machine 80 . Also, the first power supply 11 supplies power to the DC side of the inverter 20 . In the present embodiment, the rotating electrical machine 80 is a three-phase alternating current rotating electrical machine, and the inverter 20 converts power between direct current and three-phase alternating current. In addition, the rotary electric machine 80 functions both as an electric motor that is supplied with power from the first power source 11 and powered, and as a generator that generates power using power from the wheels W and the like and regenerates the power to the first power source 11 side. have

As shown in FIG. 1 , the inverter 20 includes an inverter circuit 30 including multiple switching elements 3 . The switching element 3 includes IGBT (Insulated Gate Bipolar Transistor), power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), SiC-MOSFET (Silicon Carbide-Metal Oxide Semiconductor FET), SiC-SIT (SiC-Static Induction Transistor), GaN - Power semiconductor elements such as MOSFETs (Gallium Nitride-MOSFETs) are preferably applied. As shown in FIG. 1 and the like, this embodiment exemplifies a mode in which an IGBT is used as the switching element 3 . A freewheel diode is connected in parallel to each switching element 3 with the direction from the negative electrode N to the positive electrode P (the direction from the lower side to the upper side) as the forward direction.

The inverter circuit 30 includes a plurality of sets (here, three sets) of arms 3A for one phase of AC, which are configured by a series circuit of an upper switching element 3H and a lower switching element 3L. In this embodiment, a bridge circuit is configured in which a series circuit (arm 3A) corresponds to each of the stator coils 8 corresponding to the U-phase, V-phase, and W-phase of the rotary electric machine 80 . An intermediate point of the arm 3A, that is, a connection point between the upper switching element 3H and the lower switching element 3L is connected to the three-phase stator coils 8 of the rotary electric machine 80, respectively.

As shown in FIGS. 1 and 3 , the rotating electrical machine control system 100 includes a drive power supply circuit 7 that supplies part of the drive voltage VD for driving the inverter 20 . Here, the drive voltage VD is a power supply different from the first power supply 11 and is supplied from the voltage (B) of the second power supply 19 (low voltage DC power supply) having a lower voltage than the first power supply 11 and the second power supply 19. It includes voltages (VL, VH) that are generated by the drive power supply circuit 7 using the power supplied and used in the drive circuit 2 (described later) provided in the control unit 10 . That is, the second power supply 19 supplies operating power to the control unit 10 . The first power supply 11 and the second power supply 19 are insulated from each other and have a floating relationship with each other. That is, the ground "N" of the high-voltage circuit to which power is supplied from the first power supply 11 and the ground "G" of the low-voltage circuit to which power is supplied from the second power supply 19 are in an electrically floating relationship. be.

The inverter 20 has a capacitor 5 connected in parallel to the DC side of the inverter circuit 30 . Then, when the driving voltage VD (B or VL or VH) supplied to the control unit 10 becomes less than the third specified voltage V3 (see FIG. 5), the control unit 10 performs discharge control to discharge the capacitor 5. configured to run. Although the details will be described later, when the control unit 10 executes discharge control, the inverter circuit 30 and the rotating electric machine 80 to perform active short circuit control (ASC in FIG. 5) that controls the plurality of switching elements 3 so that the current circulates between them. In this embodiment, the active short circuit control is a control that turns on all the upper switching elements 3H of the inverter circuit 30 (upper active short circuit control) or turns on all the lower switching elements 3L of the inverter circuit 30. This is the control (lower side active short circuit control) to make In the upper active short circuit control, all the lower switching elements 3L are in the OFF state, and in the lower active short circuit control, the upper switching elements 3H are all in the OFF state.

The inverter 20 further includes a discharge circuit 50 having a discharge resistor R connected in parallel to the capacitor 5, and a discharge resistance value of the discharge circuit 50 having a first resistance value and a second resistance value larger than the first resistance value. and a switch SW for switching. The discharge resistance value of the discharge circuit 50 is switched to the first resistance value by controlling the switch SW to the on state (conducting state), and is switched to the first resistance value by controlling the switch SW to the off state (non-conducting state, cutoff state). It can be switched to 2 resistance values. By providing such a discharge circuit 50, the charge accumulated in the capacitor 5 can be consumed as heat by the discharge resistor R, and the capacitor 5 can be discharged. As shown in FIG. 1 and the like, this embodiment exemplifies a form in which an IGBT is used as the switch SW. ) can also be used.

Since the first resistance value is smaller than the second resistance value, the discharge speed of the capacitor 5 can be increased by controlling the switch SW to the ON state as compared with the case of controlling the switch SW to the OFF state. Hereinafter, control of the switch SW so that the discharge resistance value of the discharge circuit 50 becomes the first resistance value (specifically, control of the switch SW to the ON state) is referred to as rapid discharge control. Although the details will be described later, when performing discharge control, the control unit 10 performs rapid discharge control in a specific state (specifically, in a state where the voltage across the terminals of the capacitor 5 is equal to or higher than the first specified voltage V1). (ADC in FIG. 5).

As shown in FIG. 1, in this embodiment, the discharge circuit 50 includes a first discharge resistor R1 and a second discharge resistor R2 that are connected in parallel to the capacitor 5, respectively. That is, the discharge circuit 50 includes two discharge resistors R connected in parallel, that is, a first discharge resistor R1 and a second discharge resistor R2. A switch SW is provided so as to electrically connect and disconnect the first discharge resistor R1 to the capacitor 5 . Specifically, a series circuit of a first discharge resistor R1 and a switch SW is connected in parallel to the capacitor 5, and the first discharge resistor R1 is electrically connected to the capacitor 5 by turning on the switch SW. The first discharge resistor R1 is electrically disconnected from the capacitor 5 by turning off the switch SW. On the other hand, the second discharge resistor R2 is not provided to be electrically disconnected from the capacitor 5, and the second discharge resistor R2 is always electrically connected to the capacitor 5.

Since the discharge circuit 50 is configured as described above, ignoring the on-resistance of the switch SW for simplification, in this embodiment, the first resistance value is the first discharge resistor R1 and the second discharge resistor R1. A combined resistance value of the parallel circuit with the resistor R2 is obtained, and the second resistance value is the resistance value of the second discharge resistor R2. In this embodiment, the resistance value of the first discharge resistor R1 is smaller than the resistance value of the second discharge resistor R2. Specifically, the resistance value of the first discharge resistor R1 is set to a relatively small value that can appropriately ensure the discharge speed of the capacitor 5 during execution of the rapid discharge control. In addition, the resistance value of the second discharge resistor R2 is set to a relatively large value that can keep the power loss low when the rotating electric machine 80 is driven (that is, when the rapid discharge control is not executed).

As described above, the rotating electric machine 80 drivingly connected to the wheels W can be used as a driving force source for a vehicle such as a hybrid vehicle or an electric vehicle. When the rotating electric machine 80 is such a vehicle driving force source, the power supply voltage of the first power supply 11 is, for example, 200 to 400 [V]. Hereinafter, the voltage on the DC side of inverter 20 (the voltage between positive electrode P and negative electrode N) will be referred to as DC link voltage Vdc. The first power source 11 is preferably configured by 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 DC side of the inverter circuit 30 is provided with the above-described capacitor 5 that functions as a smoothing capacitor (DC link capacitor) that smoothes the DC link voltage Vdc. Capacitor 5 stabilizes the DC voltage (DC link voltage Vdc) that fluctuates according to fluctuations in power consumption of rotating electric machine 80 . The voltage across the terminals of the capacitor 5 corresponds to the DC link voltage Vdc. Note that the inverter 20 may include a booster circuit that boosts the voltage of the first power supply 11 between the first power supply 11 and the inverter circuit 30 . In this case, the DC link voltage Vdc corresponds to the voltage of the first power supply 11 boosted by the booster circuit.

As shown in FIG. 1, a contactor 9 is provided between the first power supply 11 and the inverter 20 . Specifically, the contactor 9 is arranged between the capacitor 5 and the first power supply 11 . The contactor 9 can disconnect electrical connection between the electric circuit system (the capacitor 5 and the inverter circuit 30 ) of the inverter 20 and the first power supply 11 . That is, the inverter 20 is connected to the rotating electrical machine 80 and also to the first power supply 11 via the contactor 9 . When the contactor 9 is in a connected state (closed state), the first power source 11 and the inverter 20 (and the rotating electric machine 80) are electrically connected, and when the contactor 9 is in an open state (open state), the first power source 11 and the inverter 20 (and The electrical connection with the rotating electric machine 80) is cut off.

In this embodiment, the contactor 9 is a mechanical relay that opens and closes based on a command from a vehicle control device 90 (see FIG. 2), which is one of the upper control devices in the vehicle, and is called a system main relay, for example. be done. When the ignition key (main switch) of the vehicle is on (enabled), the contact of the relay is closed and the contactor 9 becomes conductive (connected), and when the ignition key is off (disabled), the relay is closed. , the contact opens and becomes non-conducting (open state). In addition to the rotary electric machine 80, the vehicle may be equipped with auxiliary machines (not shown) (air conditioner, DC/DC converter, etc.) that are driven at a relatively high voltage. These accessories may be provided in parallel with the inverter 20 , and in this case, the contactor 9 can also disconnect the electrical connection between the accessories and the first power supply 11 .

The second power supply 19 is also provided with a power switch IG interlocked with the ignition key, and for some supply destinations, the power switch IG is closed when the ignition key is in the ON state (effective state). When the ignition key is in the OFF state (ineffective state), the power switch IG opens and becomes in the non-conducting state (open state) to cut off the power supply. . For example, power is always supplied to a watch or a drive recorder that can take pictures even while the car is parked, regardless of the state of the ignition key. Power is not supplied to the control unit 10 and the drive power supply circuit 7 because the switch IG is opened.

The control unit 10 has an inverter control device 1 . The inverter control device 1 is constructed with a logic processor such as a microcomputer as a core member. The current sensor 14 detects the actual current flowing through the stator coil 8 of each phase of the rotating electric machine 80, and the inverter control device 1 acquires the detection result. Further, the magnetic pole position and rotational speed of the rotor of the rotating electric machine 80 at each point in time are detected by a rotation sensor such as the resolver 15, and the inverter control device 1 acquires the detection results. Also, the DC link voltage Vdc is detected by a voltage sensor (not shown) or the like, and the inverter control device 1 acquires the detection result. The DC link voltage Vdc is used to set a modulation rate indicating the ratio of the effective value of AC power to DC power and to determine fail-safe control (active short-circuit control), which will be described later.

The inverter control device 1 uses the detection results of the current sensor 14 and the resolver 15 based on the target torque of the rotary electric machine 80 provided from another control device such as the vehicle control device 90 to perform current feedback control by, for example, a vector control method. to control the rotating electric machine 80 via the inverter 20 . The inverter control device 1 is configured to have various functional units for motor control, and each functional unit is realized by cooperation of hardware such as a microcomputer and software (program). Since vector control and current feedback control are well known, detailed description thereof is omitted here.

A control terminal (for example, a gate terminal of an IGBT) of each switching element 3 constituting the inverter circuit 30 is connected to the inverter control device 1 via the drive circuit 2, and switching is individually controlled. The inverter control device 1 that generates the switching control signal S is an electronic circuit centered on a microcomputer or the like, and is configured as a low-voltage circuit. A low-voltage circuit differs greatly in operating voltage (circuit power supply voltage) from a high-voltage circuit such as the inverter circuit 30 . As described above, in addition to the first power supply 11, the vehicle is also equipped with the second power supply 19, which is a power supply with a voltage lower than that of the first power supply 11 (B: 12 to 24 [V], for example). The operating voltage of the inverter control device 1 having a processor such as a microcomputer as its core is, for example, 5 [V], 3.3 [V], 2.5 [V], etc. The inverter control device 1 has a second power supply Power is supplied from a power supply circuit such as a voltage regulator (not shown) that generates such an operating voltage based on the power of 19 to operate. The drive voltage VD described above may include the operating voltage of these inverter control devices 1 .

As described above, the low-voltage circuit differs greatly from the high-voltage circuit such as the inverter circuit 30 in operating voltage (circuit power supply voltage). For this reason, the rotating electric machine control system 100 (specifically, the control unit 10 ) includes a drive circuit 2 that amplifies the power of the switching control signal S for each switching element 3 . In other words, the drive circuit 2 enhances the driving capability of the switching control signal S (for example, the capability to operate the subsequent circuit such as voltage amplitude and output current) and relays it to the corresponding switching element 3 . The switching control signal S generated by the inverter control device 1 for the low-voltage circuit is supplied to the inverter 20 as the drive signal SV for the high-voltage circuit amplified by the drive circuit 2 (specifically, the switching element 3 is controlled). terminal).

A drive circuit 2 is provided corresponding to each switching element 3 . As shown in FIG. 1, in this embodiment, the inverter circuit 30 includes six switching elements 3 to be driven, and also includes six drive circuits 2 . The drive circuit 2 includes an upper drive circuit 2H that provides a drive signal SV (upper drive signal SVH) to the upper switching element 3H and a drive signal SV (lower drive signal SVL) to the lower switching element 3L. Although there is a lower-stage drive circuit 2L, it will be simply referred to as the drive circuit 2 when there is no particular need to distinguish it. Note that the control unit 10 controls the switching element 3 with the switching control signal S in a state in which the inverter control device 1 of the low-voltage circuit and the switching element 3 are electrically insulated. Therefore, the switching control signal S is input to the drive circuit 2 via an insulating element 21 such as a photocoupler or signal transformer.

In addition, since the drive signals SV for the six switching elements 3 of the inverter circuit 30 are basically electrically independent of each other, the power to the drive circuit 2 is also supplied individually. Each drive circuit 2 is individually supplied with power from a drive power supply circuit 7 . FIG. 4 shows an example of the driving power supply circuit 7. As shown in FIG. Six drive power supply circuits 7 are also provided corresponding to the six drive circuits 2 . The configuration of the six driving power supply circuits 7 is the same, and in principle, the same voltage is output unless errors due to individual differences are taken into consideration. The drive power supply circuit 7 includes a U-phase upper stage drive power supply circuit 71, a V-phase upper stage drive power supply circuit 72, a W-phase upper stage drive power supply circuit 73, a V-phase lower stage drive power supply circuit 74, and a U-phase lower stage drive power supply circuit 75. , W-phase lower-stage drive power supply circuit 76 . The three drive power supply circuits 7 (71, 72, 73) that supply power to the upper drive circuit 2H are the upper drive power supply circuit 7H, and the three drive power supply circuits 7 (71, 72, 73) that supply power to the lower drive circuit 2L. 74, 75, 76) is the lower drive power supply circuit 7L.

The upper drive power supply circuits 7H (71 to 73) are electrically insulated floating power supplies. The upper drive power supply circuit 7H has different positive potentials (VHU, VHV, VHW) and negative potentials (GHU, GHV, GHW). The lower drive power supply circuits 7L (74 to 76) have a common negative potential (GL: GLU, GLV, GLW) and are not insulated from each other, but different positive potentials (VLU, VLV, VLW). ). When indicating the positive potential of the upper driving power supply circuit 7H without distinguishing each phase, it is referred to as "VH", and when indicating the positive potential of the lower driving power supply circuit 7L without distinguishing between the phases. Referred to as "VL". The potential difference between the negative potential and the positive potential of each driving power supply circuit 7 (71 to 76) is approximately 15 to 20 [V].

As shown in FIG. 4, the driving power supply circuit 7 is configured using the secondary coil of the transformer T in order to ensure insulation from the low-voltage side circuit in which the inverter control device 1 is provided. A power supply control device 79 using a power supply control IC (Integrated Circuit) or the like is provided on the primary side of the drive power supply circuit 7, and controls switching of a switching element connected to the output voltage "B" of the second power supply 19. As a result, a prescribed output voltage is generated in the drive power supply circuit 7 . The power control device 79 performs feedback control based on the voltage generated in the secondary side circuit of the drive power supply circuit 7 to switch the switching element, and causes each drive power supply circuit 7 to generate a prescribed output voltage.

In this embodiment, the control terminal of the switch SW (for example, the gate terminal of the IGBT) is also connected to the drive circuit 2 (specifically, , and the switch drive circuit 2S) shown in FIG. Power is supplied to the switch drive circuit 2S from a drive power supply circuit 7 (not shown in FIG. 4) provided corresponding to the switch drive circuit 2S. Then, the switching control signal S for the switch SW generated by the inverter control device 1 is supplied to the switch SW as the drive signal SV (switch drive signal SVS) for the high-voltage circuit amplified by the switch drive circuit 2S ( Specifically, it is input to the control terminal of the switch SW).

Note that in a state where the inverter control device 1 can control the rotating electric machine 80 via the inverter 20, the inverter control device 1 executes control other than rapid discharge control (for example, zero torque control) to cause the capacitor 5 to It is also possible to adopt a configuration in which accumulated charges are consumed. In this case, the switch drive circuit 2S may not be provided. In the zero torque control, the electric power charged in the capacitor 5 is used as a power source, and high-loss control is executed in which a large amount of current that does not contribute to the torque of the rotating electric machine 80 flows to increase the loss. Stored charge can be consumed.

When the drive circuit 2 does not function normally or the inverter control device 1 does not function normally, the drive signal SV is not normally input to the switching element 3, and the inverter circuit 30 is not controlled normally. For example, if an abnormality occurs in the drive power supply circuit 7 or if an abnormality (for example, disconnection) occurs in the energization path between the second power supply 19 and the drive power supply circuit 7, the power supply voltage (VL, VH ) is lowered, and the drive signal SV is no longer output with the required voltage amplitude. In addition, if an abnormality occurs in the second power supply 19 or the power switch IG, or an abnormality (for example, disconnection) occurs in the energization path between the second power supply 19 and the inverter control device 1, the second power supply 19 When the supply of power is interrupted, the power supply voltage (operating voltage) of the inverter control device 1 also drops, so that the switching control signal S is no longer generated. When the voltage "B" of the second power supply 19 drops within the range in which the inverter control device 1 can operate, the drive power supply circuit 7 does not operate normally even if the switching control signal S can be generated, and the drive signal SV may not be output with the required voltage swing.

Even if the switching element 3 cannot be appropriately controlled in this manner, the rotating electrical machine 80 generates counter electromotive force when the rotating electrical machine 80 is rotating. When the drive signal SV is not output, all the switching elements 3 of the inverter circuit 30 are turned off, so that the inverter 20 is shut down and the generated power (counter electromotive force) passes through the freewheel diode. The power is regenerated to the DC side of the inverter circuit 30 . Here, if the contactor 9 is in an open state, power cannot be regenerated to the first power supply 11, and the voltage across the terminals of the capacitor 5 (DC link voltage Vdc) rises above the rated voltage of the first power supply 11. there is a possibility. As described above, in addition to the rotary electric machine 80, the vehicle may include auxiliary machines (air conditioner, DC/DC converter, etc.) (not shown) driven at a relatively high voltage in parallel with the inverter 20. be. When the voltage across the terminals of the capacitor 5 rises, the voltage applied to the auxiliary equipment also rises.

In such a case, the control unit 10 performs discharge control to protect the capacitor 5 and the auxiliary equipment from overvoltage, or to reduce the influence of the charge accumulated in the capacitor 5 on the surroundings. As described above, when executing discharge control, the control unit 10 executes rapid discharge control in a specific state. In the rapid discharge control, the DC link voltage Vdc is lowered by causing the first discharge resistor R1 to consume the charge accumulated in the capacitor 5 mainly. Further, as described above, when executing discharge control, the control unit 10 executes active short-circuit control in a specific state. In the active short circuit control, the current generated by the power generation (counter electromotive force) of the rotating electric machine 80 is consumed as heat in the stator coil 8 and the inverter circuit 30 (switching element 3 serving as a current path), thereby reducing the DC link voltage. Suppress the rise of Vdc. Braking force can also be applied to rotating electric machine 80 by executing active short circuit control. As described above, such an abnormality may be caused by an abnormality in the drive power supply circuit 7, an abnormality in the second power supply 19 (including an abnormality in the power switch IG), or an abnormality in the energization path. When these abnormalities occur, the voltages (VL, VH) of the power used in the drive circuit 2, the voltage (B) of the power supplied from the second power supply 19, and the like are supplied to the control unit 10. The driving voltage VD that is applied is lowered. Therefore, the control unit 10 performs discharge control when the driving voltage VD becomes less than the predetermined third specified voltage V3.

When the control unit 10 performs discharge control, as described above, the case where power is not supplied from the second power supply 19 is included. Therefore, the rotating electric machine control system 100 has a backup power supply circuit that generates operating power for the control unit 10 using the power on the DC side of the inverter 20 as a power source when supply of operating power from the second power supply 19 to the control unit 10 is stopped. 4. The control unit 10 performs discharge control using the operating power generated by the backup power supply circuit 4 when the supply of operating power from the second power supply 19 to the control unit 10 is stopped. A capacitor 5 is connected to the DC side of the inverter 20. When the contactor 9 is in a connected state, the capacitor 5 has the same potential as the first power supply 11 (or the voltage of the first power supply 11 after being boosted by the booster circuit). and the same potential). The backup power supply circuit 4 generates operating power for the control unit 10 using power on the DC side of the inverter 20 (that is, power charged in the capacitor 5) as a power source. If the DC link voltage Vdc is less than the voltage required for rapid discharge control or active short circuit control, the control unit 10 cannot perform rapid discharge control or active short circuit control. Since the link voltage Vdc is low, the need for these controls is low.

By the way, when the control unit 10 executes discharge control while the backup power supply circuit 4 is generating operating power for the control unit 10, by continuing to execute both the rapid discharge control and the active short circuit control, the rotation While suppressing the increase in the DC link voltage Vdc due to the back electromotive force generated by the rotation of the electric machine 80 by circulating the current between the inverter circuit 30 and the rotating electric machine 80, the charge accumulated in the capacitor 5 is mainly discharged. It is possible to reduce the DC link voltage Vdc by causing the first discharge resistor R1 to consume the power immediately. By continuing to perform both rapid discharge control and active short-circuit control, the DC link voltage Vdc performs both rapid discharge control and active short-circuit control at some point after the start of these controls. decrease to the point where it is impossible. Here, the contactor 9 is in an open state (that is, the electrical connection between the first power supply 11 and the inverter 20 is cut off), and the rotating electric machine 80 is rotating at the start of discharge control. (that is, the vehicle is running).

If the rotating electrical machine 80 is not rotating (that is, if the vehicle is stopped) at the point when the DC link voltage Vdc drops to such an extent that neither the rapid discharge control nor the active short circuit control can be performed, then , the direct current link voltage Vdc drops to zero or a state close to zero due to natural discharge of the capacitor 5 or the like. On the other hand, if rotating electric machine 80 is rotating at this time (that is, if the vehicle is not stopped), capacitor 5 is charged by the back electromotive force generated as rotating electric machine 80 rotates. DC link voltage Vdc may rise. When the DC link voltage Vdc rises, rapid discharge control and active short circuit control can be executed again to lower the DC link voltage Vdc again. Moreover, it may take a relatively long time to achieve a state in which the DC link voltage Vdc is maintained at or below the target voltage.

In FIG. 9, it is assumed that both the rapid discharge control (ADC) and the active short circuit control (ASC) are started at time T05 while the vehicle is running (that is, the vehicle speed VS is greater than zero). are doing. Also, here, it is assumed that the vehicle starts decelerating at time T05 and stops at time T09. Note that in FIG. 9, along with the time change (change with respect to time t) of each of the DC link voltage Vdc and the vehicle speed VS, the execution period ("ON") of each of the rapid discharge control (ADC) and the active short circuit control (ASC) period) and a non-execution period (period indicated by "OFF").

As shown in FIG. 9, the DC link voltage Vdc continues to drop after time T05 by starting rapid discharge control (ADC) and active short circuit control (ASC). In FIG. 9, the upper limit of the DC link voltage Vdc at which neither the rapid discharge control nor the active short circuit control can be performed is set to the second specified voltage V2. When the DC link voltage Vdc drops to the second specified voltage V2 at time T06, neither rapid discharge control (ADC) nor active short circuit control (ASC) can be executed, and at time T06 the rotating electric machine 80 is rotating. , the capacitor 5 is charged by the back electromotive force generated as the rotary electric machine 80 rotates, and the DC link voltage Vdc increases. Then, when the DC link voltage Vdc rises, the rapid discharge control and the active short circuit control are executed again at time T07, and the DC link voltage Vdc drops again to the second specified voltage V2 at time T08. As a result, as shown in FIG. 9, the drop and As the DC link voltage Vdc rises repeatedly, it takes a relatively long time to maintain the DC link voltage Vdc below the target voltage (for example, below a first specified voltage V1, which will be described later).

In view of this point, the control unit 10 controls the voltage across the terminals of the capacitor 5 (here, the DC link voltage Vdc) is equal to or higher than the first specified voltage V1, the switch SW is controlled so that the discharge resistance value of the discharge circuit 50 becomes the first resistance value, and active short circuit control is executed (that is, rapid discharge control and active short-circuit control). Further, when the control unit 10 executes discharge control while the backup power supply circuit 4 is generating operating power for the control unit 10, the voltage across the terminals of the capacitor 5 (here, the DC link voltage Vdc) is When the voltage is less than 1 specified voltage V1, the switch SW is controlled so that the discharge resistance value of the discharge circuit 50 becomes the second resistance value, and active short circuit control is executed (that is, rapid discharge control is not executed). to perform active short-circuit control).

The first specified voltage V1 is set to a value higher than the lower limit of the voltage across the terminals of the capacitor 5 (hereinafter referred to as "first lower limit voltage") at which the control unit 10 can execute active short circuit control. Here, the first specified voltage V1 is set to a value greater than the lower limit of the voltage across the terminals of the capacitor 5 (hereinafter referred to as "second lower limit voltage") at which the control unit 10 can execute rapid discharge control. The switching element 3 is a normally open switching element, and in order to control the switching element 3 to the ON state, power (here, the required voltage amplitude is power for outputting the drive signal SV to the switching element 3) is required. When the voltage across the terminals of the capacitor 5 is less than the first lower limit voltage, the control unit 10 outputs the drive signal SV (the upper drive signal SVH or the lower drive signal SVL) for the switching element 3 with a required voltage amplitude. can't In addition, the switch SW is a normally open type switch, and in order to control the switch SW to the ON state, electric power (here, a drive signal having a required voltage amplitude) is required to control the switch SW to the ON state. power for outputting the SV to the switch SW). When the voltage across the terminals of the capacitor 5 is less than the second lower limit voltage, the controller 10 cannot output the drive signal SV for the switch SW (switch drive signal SVS) with the required voltage amplitude. In this embodiment, the first lower limit voltage and the second lower limit voltage are the same or equivalent voltages.

By configuring the control unit 10 in this way, as described below with reference to the example shown in FIG. 8, the time required to realize a state in which the DC link voltage Vdc is maintained at or below the target voltage is shortened. It becomes possible to plan In FIG. 8 , in a state in which the vehicle is running (that is, a state in which the vehicle speed VS is greater than zero), at time T01, the control unit 10 is in a state in which the backup power supply circuit 4 is generating operating power for the control unit 10. It is assumed that discharge control is started at . Also, here, it is assumed that the vehicle starts decelerating at time T01 and stops at time T03. Note that in FIG. 8, as in FIG. 9, along with time changes (changes with respect to time t) of the DC link voltage Vdc and the vehicle speed VS, rapid discharge control (ADC) and active short circuit control (ASC) An execution period (a period indicated by "ON") and a non-execution period (a period indicated by "OFF") are shown.

As shown in FIG. 8, at time T01, the DC link voltage Vdc is equal to or higher than the first specified voltage V1, so the control unit 10 starts rapid discharge control (ADC) and active short circuit control (ASC) at time T01. , along with this, the DC link voltage Vdc continues to decrease after time T01. When DC link voltage Vdc drops to first specified voltage V1 at time T02, control unit 10 executes active short circuit control (ASC) without executing rapid discharge control (ADC) after time T02. In the period after time T02, the rise in the DC link voltage Vdc due to the back electromotive force generated by the rotation of the rotary electric machine 80 is suppressed by executing the active short circuit control (ASC), and the period from the time T01 to the time T02. DC link voltage Vdc can be lowered at a lower rate than . In the period after time T02, the DC link voltage Vdc decreases due to the consumption of the charge accumulated in the capacitor 5 in the second discharge resistor R2, natural discharge of the capacitor 5, and the like.

By suppressing the rate of decrease of the DC link voltage Vdc in the period after time T02 in this manner, the DC link voltage Vdc is reduced to It is possible to delay the point of time when the voltage drops to the second specified voltage V2 set to a value lower than the first specified voltage V1. As a result, it is possible to secure a long period during which the active short circuit control (ASC) is executed, and at the same time, the vehicle speed VS at the point when the DC link voltage Vdc drops to the second specified voltage V2 (in other words, the speed of the rotating electric machine 80 is increased). rotation speed) can be kept low. In the example shown in FIG. 8, the time T04 at which the DC link voltage Vdc drops to the second specified voltage V2 is later than the time T03 at which the vehicle stops. Therefore, it is possible to suppress an increase in the DC link voltage Vdc after the DC link voltage Vdc has decreased to the second specified voltage V2, or to suppress the amount of increase even if the DC link voltage Vdc increases. As a result, it is possible to reduce the time required to maintain the DC link voltage Vdc below the target voltage (for example, below the first specified voltage V1).

In this embodiment, the second specified voltage V2 is set to match the lower limit of the voltage across the terminals of the capacitor 5 at which the control section 10 can execute active short circuit control (ASC). Therefore, as shown in FIG. 8, after time T04 when the DC link voltage Vdc becomes less than the second specified voltage V2, the active short circuit control (ASC) by the control unit 10 is not executed. Thus, the control unit 10 is configured not to perform active short-circuit control when the voltage across the terminals of the capacitor 5 is less than the second specified voltage V2.

FIG. 5 shows operating conditions of the control unit 10 of this embodiment. As shown in FIG. 5, the control unit 10 starts discharge control when the drive voltage VD is less than the third specified voltage V3 (step #01: Yes). When the drive voltage VD is less than the third specified voltage V3, the backup power supply circuit 4 generates operating power for the control section 10, and the control section 10 generates the operating power for the control section 10 from the backup power supply circuit. In this state, discharge control is executed. In addition to the drive voltage VD being less than the third specified voltage V3, other conditions may be included in the conditions for starting the discharge control. For example, the discharge control start condition can include that the contactor 9 is in an open state.

When the DC link voltage Vdc (the voltage between the terminals of the capacitor 5) is equal to or higher than the first specified voltage V1 (step #02: No, step #03: No), the control unit 10 performs rapid discharge control (ADC) and active Both short circuit control (ASC) are executed (step #04). In addition, when the DC link voltage Vdc (the voltage across the terminals of the capacitor 5) is equal to or higher than the second specified voltage V2 and less than the first specified voltage V1 (step #02: No, step #03: Yes), the active short circuit control (ASC) is executed without executing the rapid discharge control (ADC) (step #05). Then, when the DC link voltage Vdc (the voltage between the terminals of the capacitor 5) is less than the second specified voltage V2 (step #02: Yes), the control unit 10 performs rapid discharge control (ADC) and active short circuit control ( ASC). Therefore, when the DC link voltage Vdc (the voltage between the terminals of the capacitor 5) is less than the second specified voltage V2 (step #02: Yes), the inverter 20 is put into a shutdown controlled state. In order to facilitate understanding, the operating conditions (functions) of the control unit 10 have been described using a flow chart, but in the present embodiment, each function shown in the flow chart of FIG. 5 is performed sequentially. Instead, as described below with reference to FIGS. 6 and 7, it is performed simultaneously by an analog circuit (specifically, the backup power supply circuit 4 included in the control unit 10).

The block diagram of FIG. 6 and the circuit diagram of FIG. 7 show a configuration example of the backup power supply circuit 4 of this embodiment. Here, a configuration example of the backup power supply circuit 4 is shown in the case where the lower-side active short-circuit control for turning on all the lower-side switching elements 3L is executed as the active short-circuit control. As shown in FIG. 6, the backup power supply circuit 4 of this embodiment includes a first determination section 41, a second determination section 42, a third determination section 43, a first drive section 44, and a second drive section 45. and has. In comparison with the functions in the flowchart of FIG. 03 ″ is realized by the second determination section 42 , the function “# 04 ” is realized by the first driving section 44 and the second driving section 45 , and the function “# 05 ” is realized by the first driving section 44 .

The first determination unit 41 outputs the first determination signal as a valid state when the drive voltage VD is less than the third specified voltage V3. Then, when the first determination signal is in a valid state and the DC link voltage Vdc is equal to or higher than the second specified voltage V2, the first drive unit 44 performs active short circuit control based on the power on the DC side of the inverter 20. It outputs an output voltage Vout that turns on the switching element 3 to be controlled. Moreover, the second determination unit 42 outputs the second determination signal as the valid state when the DC link voltage Vdc is equal to or higher than the first specified voltage V1. The third determination section 43 outputs the third determination signal as the valid state when both the first determination signal and the second determination signal are in the valid state. Then, the second drive unit 45 outputs the output voltage Vout for turning on the switch SW based on the power on the DC side of the inverter 20 when the third determination signal is in the valid state.

As shown in FIGS. 6 and 7, the output voltage Vout output by the first drive section 44 is connected to the lower drive signal SVL. The lower-side drive signal SVL becomes a signal having a voltage amplitude capable of turning on the lower-side switching element 3L by the output voltage Vout, thereby realizing lower-side active short-circuit control. Although detailed description is omitted, when the upper-stage active short circuit control is performed, the output voltage Vout is connected to the upper-stage drive signal SVH. When the control unit 10 is active, the lower limit value of the voltage across the terminals of the capacitor 5 (here, the DC link voltage Vdc) that allows the output voltage Vout for turning on the switching element 3 to be output from the first driving unit 44 This is the lower limit of the voltage across the terminals of the capacitor 5 that can execute short-circuit control. Further, in the present embodiment, the output voltage Vout output by the second drive section 45 is connected to the switch drive signal SVS. The switch drive signal SVS becomes a signal having a voltage amplitude capable of turning on the switch SW by the output voltage Vout, thereby realizing rapid discharge control. The lower limit value of the voltage across the terminals of the capacitor 5 (here, the DC link voltage Vdc) that allows the output voltage Vout for turning on the switch SW to be output from the second drive unit 45 is determined by the control unit 10 for rapid discharge. This is the lower limit of the terminal voltage of the capacitor 5 that can be controlled.

A circuit configuration example of the first determination unit 41 and the first drive unit 44 will be described below with reference to FIG. As shown in FIG. 7, the first determination unit 41 is a voltage dividing circuit having an upper stage side voltage dividing resistor R11 and a lower stage side voltage dividing resistor R12. ). The divided voltage DV by the voltage dividing circuit (R11, R12) is a voltage proportional to the drive voltage VD and is equivalent to the drive voltage VD.

The first determination signal output by the first determination unit 41 is valid when the divided voltage DV is less than the reference voltage (the voltage corresponding to the third specified voltage V3). Here, "the first determination signal (divided voltage DV) is in a valid state" means a voltage that does not allow the first transistor TR1 of the execution unit 44a, which will be described later, to transition from an off state to an on state (turn on). A state in which the first determination signal (divided voltage DV) remains at . As will be described later, the first transistor TR1 is an n-type transistor, and the first determination signal (divided voltage DV) is valid when the voltage is relatively low at which the first transistor TR1 is not turned on. 1 transistor TR1 is disabled for relatively high voltages that turn it on.

The first drive section 44 includes an execution section 44a and an output section 44b. The execution unit 44a is turned on and enabled by a constant voltage circuit (ZD1) connected between the positive electrode P and the negative electrode N on the DC side of the inverter 20 and the first determination signal (divided voltage DV) in the disabled state. and a first transistor TR1 that is turned off by a first state determination signal (divided voltage DV). As described above, the first transistor TR1 is an n-type transistor, and an n-channel FET is exemplified here. The first transistor TR1 is connected between the negative electrode N and the first node n1, which is the output node of the constant voltage circuit (ZD1). Here, the drain terminal of the first transistor TR1 is connected to the first node n1 via a diode D1 whose forward direction is the direction from the first node n1 to the first transistor TR1, and the source terminal is connected to the negative electrode N. It is connected. A control terminal (gate terminal) of the first transistor TR1 is connected to a second node n2, which is a voltage dividing point of the voltage dividing circuit (R11, R12).

The constant voltage circuit has a first Zener diode ZD1. A first node n1, which is an output node of the constant voltage circuit (ZD1), is connected to the positive electrode P via a first current limiting resistor R21. The first node n1 is connected to the control terminal of the second transistor TR2 of the output section 44b, which will be described later. output voltage. However, when the drive voltage VD is equal to or higher than the third specified voltage V3, the first transistor TR1 is on. Therefore, the first node n1, which is the output node of the constant voltage circuit (ZD1), is connected to the negative electrode N through the diode D1 and the first transistor TR1, and the potential of the first node n1 is substantially zero with respect to the negative electrode N. (excluding the forward voltage drop due to the diode D1, etc.).

On the other hand, when the drive voltage VD is less than the third specified voltage V3, the first transistor TR1 is in an off state. Therefore, no current flows through the diode D1 and the first transistor TR1. Therefore, a current flows through the constant voltage circuit (ZD1), and the potential of the first node n1 with respect to the negative electrode N becomes a voltage at which the second transistor TR2 is turned on by the constant voltage circuit (first Zener diode ZD1). The execution signal OP output by the execution unit 44a is represented by the potential with respect to the negative electrode N of the first node n1, and is valid by outputting the voltage generated by the constant voltage circuit (ZD1) when the first transistor TR1 is in the off state. state.

The output unit 44b includes a second transistor TR2 that is turned on by the enabled execution signal OP and connected to the positive electrode P. As shown in FIG. The second transistor TR2 is an n-type transistor, and an n-channel FET is exemplified here. The second transistor TR2 is connected between the positive electrode P and the negative electrode N. Here, the drain terminal of the second transistor TR2 is connected to the positive electrode P via the second current limiting resistor R31, and the source terminal is connected to the negative electrode N via the output capacitor C1. The potential of the source terminal of the second transistor TR2 with respect to the negative electrode N becomes the output voltage Vout. The negative electrode N corresponds to the output reference voltage VoutG, which is the reference voltage of the output section 44b (backup power supply circuit 4).

Note that the output voltage Vout should have a potential that can turn on the switching element 3 (here, the lower-side switching element 3L) in place of the drive signal SV (here, the lower-side drive signal SVL). (for example, about 15 to 20 [V]). On the other hand, the potential of the positive electrode P with respect to the negative electrode N fluctuates due to the back electromotive voltage of the rotating electric machine 80. Therefore, as shown in FIG. Preferably set. 3, 6, and 7, the form in which the output voltage Vout is input to the drive circuit 2 is exemplified. (gate terminal).

As described above, as the active short-circuit control, the form in which the lower-side active short-circuit control is executed has been exemplified. good too. Although details are omitted, the second determination unit 42 and the third determination unit 43 can be configured using the same circuit as the first determination unit 41 . Also, the second driving section 45 can be configured using a circuit similar to that of the first driving section 44 .

[Other embodiments]
Next, another embodiment of the rotating electric machine control system will be described.

(1) In the above embodiment, the second specified voltage V2 is set according to the lower limit of the voltage across the terminals of the capacitor 5 at which the control unit 10 can perform active short circuit control. However, without being limited to such a configuration, a configuration in which the second specified voltage V2 is set to a voltage higher than the lower limit is also possible. In this case, the period during which the active short-circuit control is executed can be avoided from becoming too long, and the heat generated by the stator coil 8 and the switching element 3 can be easily reduced.

(2) In the above embodiment, in the discharge control executed by the control unit 10 while the backup power supply circuit 4 is generating operating power for the control unit 10, the switching element 3 and the switch SW are turned on. The drive signal SV of is generated by the backup power supply circuit 4 as an example. However, without being limited to such a configuration, for example, while the backup power supply circuit 4 is generating operating power for the control unit 10, the operating power is supplied to the inverter control device 1 and the drive power supply circuit 7. It is also possible to adopt a configuration in which rapid discharge control and active short circuit control are executed by control by the inverter control device 1 . That is, the function of executing rapid discharge control and active short circuit control while the backup power supply circuit 4 is generating operating power for the control unit 10 may be implemented using a processor such as a microcomputer.

(3) In the above embodiment, the configuration in which the discharge circuit 50 includes the first discharge resistor R1 and the second discharge resistor R2 that are connected in parallel to the capacitor 5 has been described as an example. However, without being limited to such a configuration, for example, a configuration in which the discharge circuit 50 does not include the second discharge resistor R2 is also possible. In this case, to simplify, the first resistance value is the resistance value of the first discharge resistor R1, and the second resistance value is the OFF resistance value of the switch SW. Further, as in the example shown in FIG. 10, the discharge circuit 50 includes a first discharge resistor R1 and a second discharge resistor R2, which are two discharge resistors R connected in series with each other, and the switch SW is connected to one discharge resistor. R (second discharge resistor R2 in the example shown in FIG. 10) may be connected in parallel. In this case, to simplify, the first resistance value is the resistance value of the first discharge resistor R1, and the second resistance value is the combined resistance value of the series circuit of the first discharge resistor R1 and the second discharge resistor R2. becomes. In this case, the resistance value of the first discharge resistor R1 is higher than the resistance value of the second discharge resistor R2 from the viewpoint of reducing power loss when driving the rotating electric machine 80 and improving the discharge speed of the capacitor 5 during rapid discharge control. It is preferable to have a small configuration.

(4) The configurations disclosed in each of the above-described embodiments may be applied in combination with configurations disclosed in other embodiments unless there is a contradiction. combinations) are also possible. Regarding other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate without departing from the scope of the present disclosure.

[Outline of the above embodiment]
An outline of the rotating electric machine control system described above will be described below.

A rotary electric machine control system (100) for driving and controlling an AC rotary electric machine (80) drivingly connected to wheels (W) of a vehicle, wherein the rotary electric machine (80) is controlled by converting electric power between DC and AC. ), a control unit (10) that receives the supplied power and controls the inverter (20), and supplies power to the DC side of the inverter (20). A first power supply (11), a second power supply (19) that supplies operating power to the control section (10), and when supply of operating power from the second power supply (19) to the control section (10) is stopped and a backup power supply circuit (4) for generating operating power for the control unit (10) using the power on the DC side of the inverter (20) as a power source, wherein the inverter (20) includes a plurality of switching elements ( 3), a capacitor (5) connected in parallel to the DC side of the inverter circuit (30), and a discharge resistor (R) connected in parallel to the capacitor (5). a discharge circuit (50); and a switch (SW) for switching a discharge resistance value of the discharge circuit (50) between a first resistance value and a second resistance value larger than the first resistance value, the control unit (10) performs discharge control for discharging the capacitor (5) while the backup power supply circuit (4) is generating operating power for the control unit (10); is equal to or higher than the first specified voltage (V1), the switch (SW) is controlled so that the discharge resistance value of the discharge circuit (50) becomes the first resistance value, and the inverter active short-circuit control is performed to control the plurality of switching elements (3) so that current circulates between the circuit (30) and the rotating electric machine (80), and the voltage across the terminals of the capacitor (5) is When the voltage is less than the first specified voltage (V1), the switch (SW) is controlled so that the discharge resistance value of the discharge circuit (50) becomes the second resistance value, and the active short circuit control is performed. Execute.

With this configuration, when the control unit (10) executes discharge control of the capacitor (5) while the backup power supply circuit (4) is generating operating power for the control unit (10), the inverter ( 20), the discharge circuit (50 ) is controlled to the first resistance value, and active short-circuit control is executed. Here, since the first resistance value is smaller than the second resistance value, by switching the discharge resistance value of the discharge circuit (50) to the first resistance value, the discharge speed of the capacitor (5) by the discharge circuit (50) can be increased, and even when the rotating electric machine (80) is rotating, the capacitor (5) is reduced by the back electromotive force generated along with the rotation of the rotating electric machine (80) due to the execution of the active short circuit control. can suppress the rise in the voltage between the terminals of Therefore, the voltage across the terminals of the capacitor (5) can be rapidly lowered to the first specified voltage (V1).

In the above configuration, the controller (10) sets the discharge resistance value of the discharge circuit (50) to the second resistance value when the voltage across the terminals of the capacitor (5) is less than the first specified voltage (V1). The switch (SW) is controlled so that the active short circuit control is executed. Therefore, even after the voltage between the terminals of the capacitor (5) has decreased to the first specified voltage (V1), the active short circuit control is continued to suppress the rise of the voltage between the terminals of the capacitor (5) while discharging. By switching the discharge resistance value of the circuit (50) to the second resistance value, the discharge speed of the capacitor (5) by the discharge circuit (50) is suppressed, and the voltage between the terminals of the capacitor (5) suppresses the active short circuit control. It is possible to delay the point at which the voltage across the capacitor (5) falls to the lower limit where it is feasible. As a result, it is possible to secure a long period during which the active short circuit control is executed, and for example, when executing discharge control in a situation where the rotation speed of the rotating electrical machine (80) gradually decreases, the terminal of the capacitor (5) The rotational speed of the rotating electric machine (80) can be kept low at the time when the inter-voltage drops to the above lower limit. As a result, it is possible to prevent the capacitor (5) from being charged again after the capacitor (5) is discharged, or even if the capacitor (5) is charged again, the charge amount can be kept small.

Therefore, after the voltage between the terminals of the capacitor (5) drops to the first specified voltage (V1), the voltage between the terminals of the capacitor (5) can be kept low. By setting one specified voltage (V1) (for example, by setting the first specified voltage (V1) to a value lower than the target voltage), the voltage across the terminals of the capacitor (5) is maintained below the target voltage. It is possible to shorten the time required to realize the state.

Here, when the voltage between the terminals of the capacitor (5) is less than a second specified voltage (V2) set to a value smaller than the first specified voltage (V1), the control section (10) controls the The second specified voltage (V2) is configured not to execute active short-circuit control, and the second specified voltage (V2) is set to the lower limit of the voltage between the terminals of the capacitor (5) at which the control section (10) can execute the active short-circuit control. It is preferable that they are set together.

According to this configuration, the period during which the active short-circuit control is executed in the discharge control can be ensured as long as possible. Therefore, for example, when the discharge control is executed in a situation where the rotating speed of the rotating electric machine (80) gradually decreases, the rotating speed of the rotating electric machine (80) can be kept low at the time when the active short circuit control ends. As a result, it is possible to prevent the capacitor (5) from being recharged after the capacitor (5) is discharged, or even if the capacitor (5) is recharged, the amount of charge can be kept small.

The discharge circuit (50) includes a first discharge resistor (R1) and a second discharge resistor (R2) connected in parallel to the capacitor (5), and the resistance value of the first discharge resistor (R1) is is smaller than the resistance value of the second discharge resistor (R2), and the switch (SW) is provided to electrically connect and disconnect the first discharge resistor (R1) to the capacitor (5). It is preferable to have

According to this configuration, by controlling the switch (SW) so that the first discharge resistor (R1) is electrically connected to the capacitor (5), the discharge resistance value of the discharge circuit (50) is relatively By controlling the switch (SW) so that the first discharge resistor (R1) is electrically disconnected from the capacitor (5), the discharge resistance value of the discharge circuit (50) becomes relatively small. A discharge circuit (50) having a relatively large second resistance value can be appropriately formed. In the above configuration, since the resistance value of the first discharge resistor (R1) is smaller than the resistance value of the second discharge resistor (R2), the resistance value of the second discharge resistor (R2) is While setting the resistance value of the first discharge resistor (R1) to a relatively large value to reduce power loss during driving, the discharge resistance value of the discharge circuit (50) is set to the first resistance value by setting the resistance value of the first discharge resistor (R1) to a relatively small value. It is possible to improve the discharge speed of the capacitor (5) in the switched state.

The rotary electric machine control system according to the present disclosure only needs to achieve at least one of the effects described above.

3: Switching element 4: Backup power supply circuit 5: Capacitor 10: Control unit 11: First power supply 19: Second power supply 20: Inverter 30: Inverter circuit 50: Discharge circuit 80: Rotating electric machine 100: Rotating electric machine control system R: Discharge Resistor R1: First discharge resistor R2: Second discharge resistor SW: Switch V1: First specified voltage V2: Second specified voltage W: Wheel

Claims (2)

A rotary electric machine control system that drives and controls an AC rotary electric machine that is drivingly connected to wheels of a vehicle,
an inverter that converts power between direct current and alternating current and supplies alternating current power to the rotating electric machine;
a control unit that receives power and operates to control the inverter;
a first power supply that supplies power to the DC side of the inverter;
a second power supply that supplies operating power to the control unit;
a backup power supply circuit that generates operating power for the control unit by using power on the DC side of the inverter as a power source when supply of operating power from the second power supply to the control unit is stopped;
The inverter includes an inverter circuit including a plurality of switching elements, a capacitor connected in parallel to the DC side of the inverter circuit, a discharge circuit including a discharge resistor connected in parallel to the capacitor, and a discharge circuit for discharging the discharge circuit. a switch that switches a resistance value between a first resistance value and a second resistance value that is greater than the first resistance value;
When the control unit executes discharge control to discharge the capacitor while the backup power supply circuit is generating operating power for the control unit, the voltage between the terminals of the capacitor is equal to or higher than a first specified voltage. In the state, the switch is controlled so that the discharge resistance value of the discharge circuit becomes the first resistance value, and the plurality of switching elements are controlled so that current flows back between the inverter circuit and the rotating electric machine. In a state where the voltage between the terminals of the capacitor is less than the first specified voltage and equal to or higher than a second specified voltage set to a value smaller than the first specified voltage , the discharge controlling the switch so that the discharge resistance value of the circuit becomes the second resistance value, and performing the active short circuit control ;
The control unit is configured not to execute the active short circuit control when the voltage across the terminals of the capacitor is less than the second specified voltage,
The rotary electric machine control system, wherein the second specified voltage is set according to the lower limit of the voltage between the terminals of the capacitor at which the control section can execute the active short circuit control. The discharge circuit includes a first discharge resistor and a second discharge resistor connected in parallel to the capacitor,
The resistance value of the first discharge resistor is smaller than the resistance value of the second discharge resistor,
2. The rotary electric machine control system according to claim 1 , wherein said switch is provided to electrically connect and disconnect said first discharge resistor with respect to said capacitor.

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