JP2019134550A - Motor controller - Google Patents

Abstract

To provide a motor controller capable of discharging electric charges stored in a capacitor for ripple absorption using no discharge resistor.SOLUTION: A motor controller for controlling a current flowing from a power supply unit to a motor comprises: a drive circuit having a plurality of switching elements to drive the motor; a controller for controlling the drive circuit; a power source switch provided between the power supply unit and the drive circuit; and a capacitor for absorbing ripples that is provided between the power source switch and the drive circuit. When the power source switch is shifted from an on-state to an off-state, the controller controls the plurality of switching elements into a first energization pattern to make charges accumulated in the capacitor discharged through the drive circuit.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device.

  Patent Document 1 below discloses a motor control device that applies a steering assist force to a steering mechanism of a vehicle by driving an electric motor.

  The motor control device includes a drive circuit that converts a direct current from a battery into an alternating current and supplies the electric motor, a power switch provided between the battery and the drive circuit, and a power switch between the power switch and the drive circuit. And a ripple absorbing capacitor for smoothing the direct current. Then, when the ignition switch is operated to the on state, the motor control device supplies the direct current from the battery to the drive circuit by controlling the power switch to the on state. Accordingly, the drive circuit drives the electric motor by converting the direct current smoothed by the ripple absorbing capacitor into an alternating current and supplying the alternating current to the electric motor.

  By the way, from the viewpoint of safety, when the ignition switch is operated from the off state to the on state (when the electric motor is driven), the failure of the power switch according to the voltage difference between both ends of the power switch An inspection may be performed. At that time, since the fault inspection is performed using the voltage across the power switch, if there is a charge remaining in the ripple absorbing capacitor, the target voltage is affected and the determination cannot be performed correctly. Accordingly, it is necessary to discharge the ripple absorbing capacitor each time the ignition switch is turned off and the power switch is controlled to the off state.

JP 2014-172491 A

  The motor control device described in Patent Literature 1 includes a discharge resistor, and discharges the ripple absorption capacitor through the discharge resistor. Therefore, in order to discharge quickly, it is necessary to flow a large current through a low resistance. However, since the loss that occurs is large, a large resistor with excellent rated power is required, and the motor control device is enlarged. To do.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a motor control device capable of discharging electric charges stored in a ripple absorbing capacitor without using a discharge resistor.

  One aspect of the present invention is a motor control device that controls a current flowing from a power supply device to a motor, and includes a plurality of switching elements, a drive circuit that drives the motor, and a control unit that controls the drive circuit; A power switch provided between the power supply device and the drive circuit, and a ripple absorbing capacitor provided between the power switch and the drive circuit, and the control unit includes the power supply When the switch shifts from an on state to an off state, the plurality of switching elements are controlled to a first energization pattern to discharge the electric charge accumulated in the capacitor via the drive circuit. This is a motor control device.

  One aspect of the present invention is the above-described motor control device, wherein the control unit controls the first energization pattern to transfer the electric charge accumulated in the capacitor via the drive circuit. Discharge by flowing in

  One aspect of the present invention is the above-described motor control device, wherein the first energization pattern is an energization pattern that supplies the electric charge accumulated in the capacitor as a d-axis current to the motor.

  One aspect of the present invention is the above-described motor control device, wherein when the control unit determines that the ignition switch has shifted from an on state to an off state, the plurality of switching elements are connected to a second energization pattern. The q-axis current flowing through the motor is reduced to zero by controlling the power switch to zero, and after the reduction, the power switch is controlled from the on state to the off state to control the plurality of switching elements to the first energization pattern. .

  As described above, according to the present invention, it is possible to discharge the charge stored in the ripple absorbing capacitor without using the discharge resistor.

It is a figure which shows an example of schematic structure of the motor control apparatus A which concerns on one Embodiment of this invention. It is a block diagram of drive control part 12 concerning one embodiment of the present invention. It is a flowchart of operation | movement of the motor control apparatus A in the discharge control mode which concerns on one Embodiment of this invention. It is a timing chart of the motor control apparatus A in the discharge control mode which concerns on one Embodiment of this invention.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention. In the drawings, the same or similar parts may be denoted by the same reference numerals and redundant description may be omitted. In addition, the shape and size of elements in the drawings may be exaggerated for a clearer description.

  Hereinafter, motor control device A concerning one embodiment of the present invention is explained using a drawing.

  FIG. 1 is a diagram illustrating an example of a schematic configuration of a motor control device A according to an embodiment of the present invention. The motor control device A according to an embodiment of the present invention is, for example, a motor controller mounted on a vehicle. In the present embodiment, the motor control device A controls driving of an electric motor M that is a drive source of the electric power steering device.

  The electric motor M is a motor used in an electric power steering apparatus, and is a three-phase (U, V, W) brushless motor. Specifically, the electric motor M includes a rotor having a permanent magnet, and a stator in which coils Lu, Lv, and Lw corresponding to three phases (U, V, and W) are wound in order in the rotation direction of the rotor. It has. Each of the coils Lu, Lv, Lw of each phase is connected to the drive circuit 2.

  Below, the structure of the motor control apparatus A which concerns on one Embodiment of this invention is demonstrated using FIG.

  As shown in FIG. 1, the motor control device A includes a power supply device 1, a drive circuit 2, a fail safe relay circuit 3, a power switch 4, a ripple absorbing capacitor 5, a current sensor 6, a rotation angle sensor 7, and a pre-driver 8. And a control unit 9. However, the fail-safe relay circuit 3 is not an essential configuration in the present embodiment and can be omitted.

The power supply device 1 can use a secondary battery such as a nickel metal hydride battery or a lithium ion battery. The power supply device 1 can also use an electric double layer capacitor (capacitor) instead of the secondary battery. The power supply device 1 of this embodiment is a battery provided in the vehicle. The output voltage of the power supply unit 1, the battery voltage V _B.

The drive circuit 2 has a plurality of switching elements SW _{UH to} SW _WL (SW _UH , SW _UL , SW _VH , SW _VL , SW _WH , SW _WL ), and PWM (Pulse Width) Modulation (pulse width modulation) control converts the direct current from the power supply device 1 into an alternating current (phase current) and outputs it to the electric motor M. As a result, the electric motor M is driven. In the present embodiment, the case where the six switching elements SW _{UH to} SW _WL are n-type channel FETs (Field Effective Transistors) will be described. However, the present invention is not limited to this. And BJT (bipolar junction transistor).

Specifically, the switching elements SW _UH and SW _UL connected in series, the switching elements SW _VH and SW _VL connected in series, and the switching elements SW _WH and SW _WL connected in series are a power supply device. 1 is connected in parallel between the high potential (output) side of 1 and the ground potential.

The drain terminal of the switching element SW _UH is connected to the output terminal of the power supply device 1 via the power switch 4. The source terminal of the switching element SW _UL is connected to GND (ground). A connection point N1 between the source terminal of the switching element SW _{UH and} the drain terminal of the switching element SW _UL is connected to one end of the coil Lu.

The drain terminal of the switching element SW _VH is connected to the drain terminal of the switching element SW _UH . The source terminal of the switching element SW _VL is connected to GND (ground). And the source terminal of the switching element _{SW VH,} a connection point N2 between the drain terminal of the switching element _{SW VL} is connected to one end of the coil Lv.

The drain terminal of the switching element SW _WH is connected to the drain terminal of the switching element SW _UH . The source terminal of the switching element SW _WL is connected to GND (ground). And the source terminal of the switching element _{SW WH,} connection point N3 between the drain terminal of the switching element _{SW WL} is connected to one end of the coil Lw.

Each switching element SW _{UH to} SW _WL has a gate terminal connected to the pre-driver 8.

The fail safe relay 3 includes three switching elements SW _FSRU , SW _FSRV , and SW _FSRV .

The switching element SW _FSRU is connected between the connection point N1 and one end of the coil Lu, and is controlled to be in an on state or an off state by control by the control unit 9. When the switching element SW _FSRU is in the ON state, a U-phase current (hereinafter referred to as “U-phase current”) is supplied from the connection point N1 to the coil Lu. On the other hand, when the switching element SW _FSRU is in the off state, the supply of the U-phase current from the connection point N1 to the coil Lu is cut off.

The switching element SW _FSRV is connected between the connection point N2 and one end of the coil Lv, and is controlled to an on state or an off state by control by the control unit 9. When switching element SW _FSRV is in the ON state, a V-phase current (hereinafter referred to as “V-phase current”) is supplied from connection node N2 to coil Lv. On the other hand, when the switching element SW _FSRV is in the OFF state, the supply of the V-phase current from the connection point N2 to the coil Lv is interrupted.

The switching element SW _FSRW is connected between the connection point N3 and one end of the coil Lw, and is controlled to be in an on state or an off state by control by the control unit 9. When the switching element SW _FSRW is in the ON state, a W-phase current (hereinafter referred to as “W-phase current”) is supplied from the connection point N3 to the coil Lw. On the other hand, when the switching element SW _FSRW is in the OFF state, the supply of the W-phase current from the connection point N3 to the coil Lw is interrupted.

The power switch 4 is provided between the power supply device 1 and the drive circuit 2. Specifically, it is connected between the output terminal of the power supply device 1 and the drive circuit 2 (for example, the drain terminal of the switching element SW _UH ). The power switch 4 is a switch that electrically connects or disconnects the output terminal of the power supply device 1 and the drive circuit 2. For example, the power switch 4 is controlled to be in an on state or an off state by control by the control unit 9. The power switch 4 electrically connects the output terminal of the power supply device 1 and the drive circuit 2 when controlled by the control unit 9. As a result, a direct current from the power supply device 1 is supplied to the drive circuit 2. On the other hand, when the power switch 4 is controlled to be in an off state by the control unit 9, the power switch 4 electrically disconnects the output terminal of the power supply device 1 from the drive circuit 2. As a result, the direct current from the power supply device 1 is not supplied to the drive circuit 2. The power switch 4 may be a mechanical switch such as a relay or an electrical switch such as an FET.

One end of the capacitor 5 is connected between the power switch 4 and the drive circuit 2 (for example, the drain terminal of the switching element SW _UH ), and the other end is connected to GND. The capacitor 5 is a smoothing capacitor that absorbs a ripple of current supplied from the power supply device 1 to the drive circuit 2 via the power switch 4.

The current sensor 6 detects the value of the phase current flowing through each of the U-phase winding Lu, V-phase winding Lv, and W-phase winding Lw of the electric motor M. The current sensor 6 then detects the detected U-phase current value Iu, which is the current value of the U-phase current, the V-phase current value Iv, which is the current value of the V-phase current, and the W-phase current value Iw, which is the current value of the W-phase current. Are output to the control unit 9. The arrangement of the current sensor 6 shown in FIG. 1 is an example of a phase current detection unit. For example, the arrangement may be arranged between each of SW _UL , SW _VL , and SW _WL and GND.

  The rotation angle sensor 7 detects an electrical angle θ indicating the rotation position of the rotor of the electric motor M. Then, the rotation angle sensor 7 outputs the detected electrical angle θ to the control unit 9. For example, the rotation angle sensor 7 is a resolver.

The pre-driver 8 switches the switching elements SW _{UH to} SW _{WL to} the on state or the off state based on the drive signal from the control unit 9.

  The control unit 9 includes a failure determination unit 10, a power switch control unit 11, and a drive control unit 12.

The failure determination unit 10 determines whether there is an ON failure of the power switch 4 when acquiring an IG _{SW_ON} signal indicating that the ignition switch is turned on. Specifically, failure determination unit 10 reads battery voltage VB that is the output voltage of power supply device 1. Further, the failure determination unit 10 reads the voltage across the capacitor 5 (hereinafter referred to as “capacitor voltage”) Vc. If the value obtained by subtracting the capacitor voltage Vc from the read battery voltage VB is equal to or greater than a preset value (threshold value) _Vth , the failure determination unit 10 determines that the power switch 4 is not on-failed. On the other hand, if the value obtained by subtracting the capacitor voltage Vc from the read battery voltage VB is less than the threshold value _Vth , the failure determination unit 10 determines that the power switch 4 is on-failed. In the present embodiment, it is determined whether or not the power switch 4 is on-failed according to the value obtained by subtracting the capacitor voltage Vc from the battery voltage VB, but the present invention is not limited to this. For example, the failure determination unit 10 may determine that the power switch 4 is not on-failed if the capacitor voltage Vc is less than a predetermined voltage (for example, the battery voltage VB). Then, failure determination unit 10 may determine that power switch 4 is on-failed if capacitor voltage Vc is equal to or higher than the predetermined voltage.

  The power switch control unit 11 controls the power switch 4 to be on or off. Specifically, when the failure determination unit 10 determines that the power switch 4 is not on-failed, the power switch control unit 11 controls the power switch 4 from the off state to the on state. As a result, a current is supplied from the power supply device 1 to the drive circuit 2.

  When the ignition switch is turned on and the failure determination unit 10 determines that the power switch 4 is not on-failed, the drive control unit 12 shifts to a normal mode that is a mode for driving the electric motor M. In the normal mode, the drive control unit 12 controls the phase current of each phase of the UVW phase by outputting the first drive signal to the pre-driver 8 based on the torque command value output from the outside. Thereby, the electric motor M is driven. The torque command value is a value based on the steering wheel torque (operation torque) when the steering wheel is operated by the driver, and is detected by a torque sensor.

On the other hand, when the drive control unit 12 acquires the IG _{SW_OFF} signal indicating that the ignition switch is turned off, the drive control unit 12 enters the discharge control mode in which the electric motor M is discharged by supplying the electric charge stored in the capacitor 5. Transition.

  Below, the structure of the drive control part 12 which concerns on one Embodiment of this invention is demonstrated using FIG. FIG. 2 is a block diagram of the drive control unit 12 according to an embodiment of the present invention.

  As shown in FIG. 2, the drive control unit 12 includes a state transition processing unit 13, a target dq axis current setting unit 14, a three-phase / two-axis conversion unit 15, a current control unit 16, and a gate drive signal generation unit 17. .

The state transition processing unit 13 performs switching between the normal mode and the discharge control mode. Specifically, when the state transition processing unit 13 acquires the IG _{SW_ON} signal and the failure determination unit 10 determines that the power switch 4 is not on-failed, the state transition processing unit 13 normally outputs a mode command signal. The mode signal is output to the target dq axis current setting unit 14. On the other hand, when acquiring the IG _{SW_OFF} signal, the state transition processing unit 13 outputs a discharge control mode signal to the target dq axis current setting unit 14 as a mode command signal.

The target dq axis current setting unit 14 acquires a torque command value from the torque sensor. Further, the target dq-axis current setting unit 14 acquires the electrical angle θ from the rotation angle sensor 7. Then, the target dq-axis current setting unit 14 is a target d-axis current value Id _ref that is a target value of the d-axis current and a target value of the q-axis current according to the acquired torque command value and the electrical angle θ. A target q-axis current value Iq _ref is set. However, the target dq-axis current setting unit 14 calculates the target d-axis current value and the target q-axis current value regardless of the torque command value when the discharge control mode signal is acquired from the state transition processing unit 13. . Specifically, when the target dq axis current setting unit 14 obtains the discharge control mode signal from the state transition processing unit 13, the target dq axis current setting unit 14 sets the target d axis current value to a predetermined value and sets the target q axis current value. Set to zero. The target dq-axis current setting unit 14 outputs the set target d-axis current value Id _ref and target q-axis current value Iq _ref to the current control unit 16.

  The three-phase to biaxial conversion unit 15 uses the electrical angle θ acquired from the rotation angle sensor 7 for the U-phase current value Iu, the V-phase current value Iv, and the W-phase current value Iw acquired from the current sensor 6. The shaft current value Id and the q-axis current value Iq are converted. For conversion from the U-phase current value Iu, the V-phase current value Iv, and the W-phase current value Iw to the d-axis current value Id and the q-axis current value Iq, the following expressions (1) and (2) are used. Used.

Id = √ (2/3) × (−Iu × cos θ−Iv × cos (θ−2π / 3) −Iw × cos (θ−4π / 3)) (1)
Iq = √ (2/3) × (Iu × sin θ + Iv × sin (θ−2π / 3) + Iw × sin (θ−4π / 3)) (2)

  The three-phase / biaxial conversion unit 15 outputs the d-axis current value Id and the q-axis current value Iq to the current control unit 16.

The current control unit 16 calculates PI with respect to a deviation Δd between the target d-axis current value Id _ref acquired from the target dq-axis current setting unit 14 and the d-axis current value Id acquired from the three-phase / two-axis conversion unit 15. To calculate a d-axis voltage command value Vd, which is a d-axis voltage for making the deviation Δd approach zero. In addition, the current control unit 16 determines the deviation Δq between the target q-axis current value Iq _ref acquired from the target dq-axis current setting unit 14 and the q-axis current value Iq acquired from the three-phase / two-axis conversion unit 15. By executing the PI calculation, a q-axis voltage command value Vq that is a q-axis voltage for making the deviation Δq approach zero is calculated.

  Next, the current control unit 16 uses the electrical angle θ acquired from the rotation angle sensor 7 for the calculated d-axis voltage command value Vd and q-axis voltage command value Vq as the voltage command value for each phase of the UVW phase. It converts into a certain U-phase voltage command value Vu, V-phase voltage command value Vv, and W-phase voltage command value Vw. For conversion from the d-axis voltage command value Vd and the q-axis voltage command value Vq to the U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw, the following equation (3) (5) is used.

Vu = −Vd × cos θ + Vq × sin θ (3)
Vv = −Vd × cos (θ−2π / 3) + Vq × sin (θ−2π / 3) (4)
Vw = −Vd × cos (θ−4π / 3) + Vq × sin (θ−4π / 3) (5)

  The current control unit 16 generates drive signals indicating duty ratios corresponding to the converted U-phase voltage command value Vu, V-phase voltage command value Vv, and W-phase voltage command value Vw, and outputs them to the pre-driver 8. Thus, in the normal mode, the pre-driver 8 generates torque by controlling the phase current of each phase based on the drive signal (first drive signal) from the current control unit 16. That is, in the normal mode, since the q-axis current flows through the electric motor M, the electric motor M is driven.

  On the other hand, in the discharge control mode, the target d-axis current value is set to a predetermined value, and the target q-axis current value is set to zero. Therefore, in the discharge control mode, the pre-driver 8 controls the phase current of each phase based on the drive signal (second drive signal) from the current control unit 16, thereby controlling the d-axis with respect to the electric motor M. Control so that current flows only through Here, in the discharge control mode, the power switch 4 is controlled to be turned off. Therefore, in the discharge control mode, the electric charge stored in the capacitor 5 is supplied to the drive circuit 2 and supplied to the electric motor M as a d-axis current. Thereby, the electric charge stored in the capacitor 5 can be discharged without driving the electric motor M.

  Hereinafter, an operation flow of the motor control device A in the discharge control mode according to the embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart of the operation of the motor control device A in the discharge control mode according to the embodiment of the present invention. FIG. 4 is a timing chart of the motor control device A in the discharge control mode according to the embodiment of the present invention.

The motor control device A receives an IG _{SW_OFF} signal when the ignition switch is operated from the on state to the off state. For example, the motor control device A, at time _{T 1,} (step S101) in the case of obtaining the _{IG SW_OFF} signal, the target dq-axis current setting portion 14, for reducing (reduced) the q-axis current value Iq to zero The target q-axis current value Iq _ref is set to zero.

Thus, the control unit 9 controls the switching element _SW UH _{to SW WL} to turn on or off energization pattern to reduce the q-axis current (the second energization pattern) (step S102). The energization pattern is a switching pattern for turning on or off the switching elements SW _{UH to} SW _WL , and is continuously turned on (“ON”) or continuously turned off “OFF”. It is a combination of a state (period other than “ON” or “PWM (Pulse Width Modulation)”) or a state that is controlled to be turned on or off at a certain cycle (PWM controlled state) (“PWM”) .

At time T _2, when the q-axis current value Iq is in a state capable equated to zero or zero, it proceeds to a discharge control mode, controlled to be off the power switch control unit 11 is a power switch 4 from the on state (Step S103). Thereby, the supply of the direct current from the power supply device 1 to the drive circuit 2 is interrupted, and the electric charge stored in the capacitor 5 is supplied to the drive circuit 2.

Here, the target dq-axis current setting unit 14 sets the target d-axis current value Id _ref to a predetermined value. Accordingly, the control unit 9 switches the switching elements SW _{UH to} SW _WL to the on state or the off state with the energization pattern (first energization pattern) for controlling the d-axis current to a predetermined value while controlling the q-axis current to zero. Control (step S104). Therefore, the electric charge stored in the capacitor 5 by the drive circuit 2 is supplied to the electric motor M as a d-axis current, and the electric charge stored in the capacitor 5 is discharged (step S105).

The control unit 9 determines whether or not the capacitor voltage Vc is equal to or _lower than the threshold value V _cth while controlling the switching elements SW _{UH to} SW _WL to be in an on state or an off state with the first energization pattern (step S106). That is, the control unit 9 determines whether or not the capacitor voltage Vc, which has decreased due to the discharge of the electric charge stored in the capacitor 5, has become equal to or _lower than the threshold value V _cth . This threshold value V _cth is, for example, the operating voltage of the pre-driver 8. Note that the threshold value V _cth is a level at which there is no problem in determining whether the power switch 4 is on or not. That is, the threshold value V _cth is a value that satisfies the condition of (battery voltage _VB− threshold value V _cth )> threshold value V _th .

When the capacitor voltage Vc becomes equal to or lower than the threshold value V _cth (time T ₃ ), the controller 9 stops energization with the first energization pattern (step S107). Thereby, the discharge of the electric charge stored in the capacitor 5 is stopped. Therefore, the electric charge stored in the capacitor 5 can be discharged to the extent that there is no problem in determining whether the power switch 4 is on or not while securing the operating voltage of the pre-driver 8.

  The controller 9 stops the operation of the electric motor M of the drive circuit 2, and the power source of the motor control device A is turned off (step S108).

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

  As described above, the motor control device A allows the capacitor 5 to be driven without driving the electric motor M by energizing only the d-axis current to the electric motor M after the power switch 4 shifts from the on state to the off state. The charge accumulated in is discharged.

  In the above-described embodiment, when the control unit 9 determines that the ignition switch has shifted from the on state to the off state, the control unit 9 controls the plurality of switching elements to the second energization pattern, thereby causing the electric motor M to Although the flowing q-axis current is reduced to zero, the invention is not limited to this. For example, when the control unit 9 determines that the ignition switch has transitioned from the on state to the off state, the control unit 9 controls the plurality of switching elements to the second energization pattern, whereby the q-axis current flowing through the electric motor M and Both currents of the d-axis current may be reduced to zero.

  In the above embodiment, the controller 9 discharges the charge accumulated in the capacitor 5 via the drive circuit 2 when it is determined that the ignition switch has shifted from the on state to the off state. Is not limited to this. For example, the control unit 9 executes the discharge control mode, that is, the capacitor after the ignition switch has shifted from the off state to the on state and before the failure determination unit 10 determines whether or not the power switch 4 is on. The charge accumulated in 5 may be discharged via the drive circuit 2.

  According to such a configuration, the electric charge accumulated in the capacitor 5 can be discharged quickly without using a discharge resistor. Therefore, cost reduction for circuit reduction and increase in size of the motor control device A can be suppressed.

A Motor control device 1 Power supply device 2 Drive circuit 3 Fail safe relay circuit 4 Power switch 5 Capacitor 6 Current sensor 7 Rotation angle sensor 8 Pre-driver 9 Control unit

Claims (4)

A motor control device for controlling a current flowing from a power supply device to a motor,
A drive circuit comprising a plurality of switching elements and driving the motor;
A control unit for controlling the drive circuit;
A power switch provided between the power supply device and the drive circuit;
A ripple absorbing capacitor provided between the power switch and the drive circuit;
With
The control unit controls the plurality of switching elements to a first energization pattern when the power switch shifts from an on state to an off state, thereby reducing the charge accumulated in the capacitor to the drive circuit. A motor control device characterized by discharging through the motor.   2. The control unit according to claim 1, wherein the controller controls the first energization pattern to discharge the electric charge accumulated in the capacitor by flowing the electric motor through the driving circuit. Motor control device.   The motor control device according to claim 2, wherein the first energization pattern is an energization pattern that supplies the electric charge accumulated in the capacitor as a d-axis current to the motor.   When it is determined that the ignition switch has shifted from the on state to the off state, the control unit reduces the q-axis current flowing through the motor to zero by controlling the plurality of switching elements to the second energization pattern. Then, after the reduction, the power switch is controlled from the on state to the off state to control the plurality of switching elements to the first energization pattern. The motor control device described in 1.

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