JP2019062589A - Motor control device and motor control method - Google Patents

Abstract

To provide a motor control device that can: suppress an excessive amplitude increase of d-axis current of an AC motor in the negative direction when a three-phase short-circuit is implemented; minimally suppress an increase of voltage between capacitor terminals even when an inverter circuit is cut off from a DC power supply; and prevent destruction of the inverter circuit and/or the motor.SOLUTION: A switching control unit for on-off controlling switching elements of a power inverter circuit determines whether or not there is a fear that a permanent magnet of a motor is demagnetized by the minimum value of d-axis current of an AC motor after implementing a three-phase short-circuit, which turns on all of the upper-stage-side switching elements or all of the lower-stage-side switching elements, when the three-phase short-circuit is implemented. When it is determined that the permanent magnet of the motor is not demagnetized, a three-phase short-circuit processing command generation unit generates a three-phase short-circuit processing command for starting the three-phase short-circuit.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a motor control device and a motor control method for driving and controlling an AC motor.

An electric vehicle using an AC motor as a driving power source powers the AC motor to generate a traveling drive torque during traveling, and regenerates the AC motor to generate regenerative braking torque during braking.
The drive system of the electric vehicle is composed of a DC power supply consisting of a secondary battery such as a lithium ion battery, an inverter circuit connected to the DC power supply, and an AC motor connected to the inverter circuit as a load.

  The inverter circuit comprises a capacitor and a plurality of semiconductor switches, and turns on and off the plurality of semiconductor switches at a predetermined switching frequency to convert direct current power of the direct current power supply into predetermined alternating current power, thereby achieving torque and rotation of the alternating current motor. I have adjusted the number. In addition, the AC motor operates as a generator depending on the operating condition, and charges the DC power supply with regenerated power generated by power generation. In addition, as an AC motor applied to an electric vehicle, an efficient permanent magnet type three-phase synchronous motor is generally used.

In the case of a drive system using a three-phase synchronous motor, the inverter circuit is configured by connecting in series with a DC power supply three series circuits in which upper and lower switching elements are connected in series. The respective middle points of the three series circuits are connected to the respective U-phase, V-phase and W-phase inputs of the three-phase synchronous motor.
Then, by sequentially turning on and off the switching elements provided in each phase of the inverter circuit, AC power different in phase by 120 degrees from each other is supplied to each phase of the three-phase synchronous motor to drive the three-phase synchronous motor. Hereinafter, unless otherwise specified, the motor refers to a three-phase synchronous motor. Note that the operation principle of the inverter circuit is wide and general, so the description is omitted here.

  The drive system of the electric vehicle is provided with switching means for disconnecting the DC power supply and the inverter circuit as necessary in order to protect the DC power supply consisting of a secondary battery such as a lithium ion battery from overvoltage and overcurrent. There is. As the open condition of the switching means, when the voltage of the DC power supply becomes equal to or higher than a predetermined value during regenerative operation of the motor, the current flowing to the DC power supply becomes lower when the DC power supply voltage becomes lower than a predetermined value due to consumption of the DC power supply. There are cases such as when the value exceeds a predetermined value. In addition, the opening and closing means may be opened due to a failure or a collision of the vehicle.

  In a drive system provided with such opening and closing means, the opening and closing means may be opened during regenerative operation of the motor, and the inverter circuit may be electrically disconnected from the DC power supply. Further, even in a drive system having no opening / closing means, the inverter circuit may be disconnected from the DC power supply when the power line between the DC power supply and the inverter circuit is disconnected.

  Thus, when the inverter circuit is separated from the DC power supply, the regenerative power flowing from the motor into the inverter circuit can not be charged to the DC power supply, and the capacitor of the inverter circuit is charged, and the capacitor is damaged by an overvoltage There is a fear. Therefore, when the inverter circuit is disconnected from the DC power supply, a three-phase short circuit is performed to turn on all of the upper stage switching elements or all of the lower stage switching elements of the inverter circuit. However, when this three-phase short circuit is executed, the electric current stored in the stator coil sharply rises due to the electric power stored in the stator coil of the motor, and at this time the current flowing in the stator coil causes the permanent magnet of the motor to be irreversible. The problem of demagnetization occurs.

  In order to solve this problem, for example, Patent Document 1 proposes a method of setting the maximum current value of the current of the permanent magnet synchronous motor coil and controlling the current of the motor coil to be less than the maximum current value. ing. In the control shown in this patent document 1, the setting of the maximum current value of the current of the motor coil is made of the irreversible demagnetization current value corresponding to the permanent magnet temperature and the transient current generated at the time of the three phase short circuit. One of the pair and the pair of the strength of the irreversible demagnetization generating magnetic field corresponding to the permanent magnet temperature and the strength of the demagnetizing field of the permanent magnet of the permanent magnet synchronous motor generated at the time of the three phase short circuit. It is made to determine for every rotation speed of a permanent magnet synchronous motor based on a group.

JP, 2014-54064, A

  In the inverter control device of the permanent magnet synchronous motor of Patent Document 1, as described above, in order to prevent irreversible demagnetization of the permanent magnet of the motor which may occur due to the transient current generated at the time of the three phase short circuit. The maximum current value of the current flowing through the motor coil is set, but this maximum current value is a combination of an irreversible demagnetizing current value corresponding to the permanent magnet temperature and a transient current generated in the case of a three-phase short circuit. And one of a set of the strength of the irreversible demagnetization generation magnetic field corresponding to the permanent magnet temperature and the set of the demagnetization field strength of the permanent magnet of the motor generated at the time of the three phase short circuit. And the current of the motor is controlled so that the current value of the motor is less than the maximum current value, so that the desired required torque can not be output from the motor. As a result, This inverter control When applied to location in the electric vehicle has a problem such desired acceleration characteristic can not be obtained.

  Further, in the inverter control device for a motor of Patent Document 1, the sets of irreversible demagnetization current values corresponding to permanent magnet temperatures and transient currents generated in the case of three-phase short circuit are obtained in advance by the finite element method, If it is necessary to create a table indicating the relationship of the table, and it takes a lot of man-hours to create the table, and the computing device which can not secure sufficient memory capacity for storing the table, the size of the table itself is small. As a result, there is a problem that the accuracy of the irreversible demagnetization current becomes coarse or the irreversible demagnetization current itself can not be obtained.

  The present invention has been made to solve the problems as described above, and suppresses the increase in phase current when a three-phase short circuit is performed, and also maximizes the maximum current in the state where a normal three-phase short circuit is not performed. It is an object of the present invention to provide a motor control device and a motor control method capable of generating a desired maximum torque at the time of acceleration / deceleration by preventing the excessive limitation of the above.

  A motor control device and a motor control method according to the present invention are a motor control device connected between a DC power supply and an AC motor, converting DC power of the DC power supply into AC power to drive and control the AC motor. And a switching control unit that turns on / off the switching elements of the power conversion circuit, and the switching control unit includes: When performing a three-phase short circuit that turns on all of the upper stage switching elements or all of the lower stage switching elements, the minimum value of d-axis current after execution of the three phase short circuit does not demagnetize the permanent magnet of the motor A determination unit for determining whether or not the three-phase short circuit is started when it is determined that the permanent magnet of the motor is not to be demagnetized. It is characterized in that it has a three-phase short-circuiting command generating unit that generates a short-circuit processing command output.

According to the motor control device and the motor control method according to the present invention, the irreversible demagnetization of the permanent magnet of the motor due to the transient current generated when the power line of the motor is short-circuited by three phases can be prevented. The torque reduction due to the demagnetization of the permanent magnet can be prevented.
Furthermore, when the transition to the three-phase short circuit mode is not determined, the excessive maximum torque is not suppressed, so that the torque corresponding to the desired required torque can be output from the motor when the power is normal. Thus, for example, in the electric vehicle, it is possible to output a torque corresponding to the acceleration / deceleration request from the host controller, and it is thereby possible to realize a desired acceleration / deceleration characteristic.

It is a block block diagram which shows the drive system by which the motor control apparatus which concerns on Embodiment 1, 2 of this invention was mounted. It is a block block diagram which shows the switching control part of the motor control apparatus which concerns on Embodiment 1 of this invention. It is a characteristic view showing the time waveform of the current at the time of three phase short circuit of the motor control device concerning Embodiment 1 of this invention. It is a flowchart which shows a process of the three-phase short circuit process command production | generation part of the motor control apparatus concerning Embodiment 1 of this invention. It is a block block diagram which shows the switching control part of the motor control apparatus which concerns on Embodiment 2 of this invention. It is a flowchart which shows the process of the three-phase short circuit process instruction | command production | generation part of the motor control apparatus concerning Embodiment 2 of this invention.

Hereinafter, preferred embodiments of a motor control device and a motor control method according to the present invention will be described with reference to the drawings. In addition, about the part which is the same or corresponds in each figure, the same code | symbol is attached | subjected and demonstrated.
Generally, a motor also called a motor converts electric power into driving force to perform power running, but it is possible to reversely convert driving force to electric power to perform regenerative operation with the same structure. Moreover, although the generator also called a generator converts driving power into electric power and carries out regeneration driving | operation, it is possible to reversely convert electric power into driving power and carry out power running operation with a structure as it is.
That is, the motor and the generator have basically the same structure, and both are capable of power running operation and regenerative operation. Therefore, in this specification, a rotary electric machine having the functions of both a motor and a generator is simply referred to as a motor.

Embodiment 1
Hereinafter, a motor control device and a motor control method according to Embodiment 1 of the present invention will be described in detail based on FIGS. 1 to 4. FIG. 1 is a block diagram showing a system in which a motor control device and a motor control method according to Embodiment 1 of the present invention are installed. In FIG. 1, a DC power supply 90 such as a battery that supplies DC power to the inverter circuit and is charged with regenerative power, and a three-phase synchronous motor 10 to be controlled are illustrated.

  In FIG. 1, motor control device 80 is connected to DC power supply 90 by DC bus 1a on the positive electrode side and DC bus 1b on the negative electrode side through power switch 70, and exchanges drive power and regenerative power with DC power supply 90. Do. Further, the motor control device 80 is connected to the motor 10 by the AC bus 2 and exchanges driving power and regenerative power with the motor 10.

Further, the motor 10 is provided with a rotation angle sensor 30 for detecting the rotation angle θm of the motor. The motor 10 is a motor capable of rotationally driving the load and capable of regenerating the rotational energy of the load as electrical energy, and for example, a permanent magnet three-phase AC synchronous motor or a three-phase brushless motor is used.
Further, the motor control device 80 is configured of an inverter circuit 20 and a switching control unit 60. The inverter circuit 20 includes a capacitor 21 connected between the DC bus 1a on the positive side of the power supply input and the DC bus 1b on the negative side, a voltage detection unit 24 for detecting the DC bus voltage of the inverter circuit 20, and And a motor current detection unit 26 for detecting the current of the motor 10 flowing through the AC bus 2.

  The capacitor 21 has a function of suppressing the ripple of the DC bus voltage, a function of reducing the power supply impedance of the inverter circuit 20 to improve the alternating current drive capability of the inverter circuit 20, and a function of absorbing a surge voltage. . Further, the voltage detection unit 24 divides the DC bus voltage into a voltage that can be read by the switching control unit 60 using a voltage dividing resistor or the like, and outputs the DC bus voltage information to the switching control unit 60.

The power conversion circuit 25 is an inverter in which six switching elements, which are generally well known, are full-bridge connected. That is, as shown in FIG. 1, in the switching elements 31, 32, the switching elements 33, 34, and the switching elements 35, 36, the upper stage switching element and the lower stage switching element are connected in series, respectively. Are connected in parallel to.
The middle point of the switching elements 31 and 32 is connected to the U-phase input of the motor 10, the middle point of the switching elements 33 and 34 is connected to the V-phase input of the motor 10, and the middle point of the switching elements 35 and 36 Is connected to the W-phase input of the motor 10.

The switching elements 31, 33 and 35 connected to the DC bus 1a on the positive electrode side of the DC power supply 90 are referred to as upper stage switching elements, and the switching elements 32 connected to the DC bus 1b on the negative electrode side of the DC power supply 34 and 36 are referred to as lower stage switching elements.
As a switching element, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) as shown in FIG. 1, an IGBT (Insulated Gate Bipolar Transistor), etc. other than the MOSFET are used.
Further, in each MOSFET of the switching element, free wheel diodes (FWD) are provided in parallel, with the direction from the negative electrode side to the positive electrode side of the DC power supply 90, that is, the direction from the lower side to the upper side as a forward direction. .

  The motor current detection unit 26 detects a motor current flowing through the AC bus 2, converts the current into a voltage, and outputs motor current information to the switching control unit 60. In FIG. 1, the structure which detects an electric current by shunt resistance is shown. The motor current detection unit 26 may be a current sensor using a Hall element or the like.

  The power switch 70 controls power exchange between the DC power supply 90 and the motor control device 80. Specifically, when the voltage of DC power supply 90 exceeds the set value during regenerative operation of motor 10, power switch 70 causes the voltage of DC power supply 90 to fall below the set value due to consumption of DC power supply 90 or the like. In this case, when the current flowing through the DC power supply 90 becomes equal to or higher than the set value, and when a failure or a collision of the vehicle is detected, the host system (not shown) is controlled to open. The power switch 70 may be configured to be controlled by the switching control unit 60.

Further, the rotation angle sensor 30 detects the rotor rotation angle θm of the motor 10 by a resolver, an encoder or the like. The rotor rotation angle θm detected by the rotation angle sensor 30 is output to the switching control unit 60. The rotor rotation angle θm is converted to an electrical angle θe based on the number of pole pairs of the permanent magnet of the motor 10.
The switching control unit 60 controls the entire motor control device, and includes a microcontroller, a drive circuit, and the like.
FIG. 2 is a block diagram showing a switching control unit of the motor control device according to Embodiment 1 of the present invention.

  In FIG. 2, the switching control unit 60 includes a current command generation unit 61, a three-phase to two-phase conversion unit 62, a current control unit 63, a two-phase to three-phase conversion unit 64, a duty conversion unit 65, a PWM signal generation unit 66, three-phase A short circuit processing command generation unit 67, a power supply side abnormality determination unit 68, and a current command selection unit 69 are provided.

The torque command Trq * is input to the current command generation unit 61 from the upper system (not shown). Current command generation unit 61 generates d-axis current command value Id * and q-axis current command value Iq * based on this torque command value Trq *.
Here, the d-axis indicates the magnetic pole position of the motor 10, that is, the direction of the magnetic flux, and the q-axis electrically indicates the direction orthogonal to the d-axis, and constitutes a dq axis coordinate system. When the rotor of the motor 10 having a magnet rotates, the dq axis coordinate system also rotates.

  The current command selection unit 69 receives the d-axis current command value Id * and the q-axis current command value Iq * from the current command generation unit 61 and the power supply side abnormality determination result Err from the power supply side abnormality determination unit 68 described later. A final d-axis current command value Id2 * and a final q-axis current command value Iq2 * are generated.

  The details of the current command selection unit 69 will be described. Inside the current command selection unit 69, the changeover switch 102, the abnormal d-axis current command generator 100, and the abnormal q-axis current command generator 101 are configured. In response to the signal of the power supply side abnormality judgment result Err from the power supply side abnormality judging unit 68 described later, the changeover switch 102 receives the d axis current command value Id * and the q axis current command value Iq * from the current command generating unit 61, The final d axis current is switched by switching between the abnormal d axis current command value Id0 * from the abnormal d axis current command generator 100 and the abnormal q axis current command value Iq0 * from the abnormal q axis current command generator 101. The command value Id2 * and the final q-axis current command value Iq2 * are output. The set values of the abnormal d-axis current command generator 100 and the abnormal q-axis current command generator 101 will be described in detail later.

The three-phase / two-phase conversion unit 62 coordinates based on the U-phase current Iu, the V-phase current Iv and the W-phase current Iw input from the motor current detection unit 26 and the electrical angle θe input from the rotation angle sensor 30. The conversion converts the U-phase current Iu, the V-phase current Iv and the W-phase current Iw into a d-axis current detection value Id and a q-axis current detection value Iq.
In the first embodiment of the present invention, the currents detected by motor current detection unit 26 are three phase currents Iu, Iv and Iw, but if two phase currents are known, the remaining phase currents are determined. Therefore, two phase currents among the phase currents Iu, Iv, and Iw may be detected.

  The current control unit 63 receives the final d-axis current command value Id2 * and the final q-axis current command value Iq2 * from the current command selection unit 69, and the d-axis current detection value Id from the three-phase to two-phase conversion unit 62. And the q-axis current detection value Iq is input. Then, current control unit 63 sets the d-axis current deviation between d-axis current command value Id * of the output of current command generation unit 61 and d-axis current detection value Id of the output of three-phase / two-phase conversion unit 62, and q. Calculates the q-axis current deviation between the axis current command value Iq * and the q-axis current detection value Iq, and calculates the d-axis voltage command value Vd * and the q-axis voltage command value by proportional / integral control calculation for each current deviation. Calculate Vq *.

  The two-phase to three-phase conversion unit 64 receives information of the d-axis voltage command value Vd * and the q-axis voltage command value Vq * of the output from the current control unit 63 and the electrical angle θe obtained by the rotation angle sensor 30 Based on these, the three-phase voltage command values Vu *, Vv *, Vw * of the stationary coordinate system are calculated, and are output to the duty conversion unit 65.

  The duty conversion unit 65 receives the three-phase voltage command values Vu *, Vv *, Vw * from the two-phase / three-phase conversion unit 64 and the DC bus voltage Vpn from the voltage detection unit 24, and performs duty instruction based on these. The values Du, Dv, Dw are calculated and output to the PWM signal generation unit 66.

  The power supply abnormality determination unit 68 receives the DC bus voltage Vpn from the voltage detection unit 24, determines whether or not there is a power supply abnormality based on the DC bus voltage Vpn, and generates a power supply abnormality determination result Err. Do.

The three-phase short circuit processing command generation unit 67 determines the power-side abnormality determination of the d-axis current detection value Id and the q-axis current detection value Iq of the output from the three-phase two-phase conversion unit 62 and the output from the power supply side abnormality determination unit 68 In response to the result Err, a three-phase short circuit processing command S3PS is generated based on these results.
Specifically, when the three-phase short circuit processing command generation unit 67 indicates that the power source side abnormality determination result Err indicates that the power source side is in the normal state, the three phase short circuit processing command S3PS is used as the three phase short circuit processing command S3PS. If a non-execution command is generated and the power supply side abnormality judgment result Err indicates that the power supply side is in an abnormal state, the d axis current detection value Id, the q axis current detection value Iq and the DC bus voltage Vpn A three-phase short circuit execution command is generated as a three-phase short circuit processing command S3PS based on the above.

The PWM signal generation unit 66 receives the duty command values Du, Dv, Dw of each phase from the duty conversion unit 65, and the three-phase short circuit processing instruction S3PS from the three-phase short circuit processing instruction generation unit 67. The on-off control signal to each switching element of the power conversion circuit 25 is calculated, and the on-off control signals UH, UL, VH, VL, WH, and WL are output to the power conversion circuit 25.
Specifically, when three-phase short circuit processing command S3PS is a three-phase short circuit non-execution command, PWM signal generation unit 66 sends to each switching element according to duty command values Du, Dv, Dw of each phase. A three-phase short circuit state in which all the upper side switching elements of the power conversion circuit 25 or all the lower side switching elements are turned on when the on / off control signal is output and the three phase shorting processing command S3PS is a three phase shorting execution command The on / off control signal to each switching element is output so that

  Switching elements 31 to 36 of power conversion circuit 25 perform on / off operation by on / off control signals UH, UL, VH, VL, WH, and WL from switching control unit 60, respectively, convert DC power into AC power and supply it to motor 10. At the same time, the DC power supply 90 is charged with the regenerative power generated by the motor 10 in the regenerative state.

  Here, the feature of the motor control device according to the first embodiment of the present invention is that the switching control unit 60 includes the three-phase short circuit process command generation unit 67, the power source side abnormality determination unit 68, and the current command selection unit 69. If the power supply side abnormality judgment unit 68 judges that the power supply side is in an abnormal state, the final d-axis current command value Id2 * and the final q-axis current command value Iq2 * which are the outputs of the current command selection unit 69 are provided. Respectively, the d-axis current command Id * is switched to the output “−d / Ld” of the d-axis current command generator 100 at fault, and the q-axis current command Iq * is output “0” at q-axis current command generator 101 at fault. The three-phase short circuit processing command generation unit 67 generates a three-phase short circuit execution command based on the d-axis current detection value Id and the q-axis current detection value Iq, and executes the three-phase short circuit.

  With this configuration, as described later, when performing the three-phase short circuit after the abnormality determination of the power supply side abnormality determination unit 68, the minimum value of the d-axis current after the three-phase short circuit execution demagnetizes the permanent magnet of the motor A three-phase short circuit can be started at a timing when the d-axis current value does not occur. That is, when performing a three-phase short circuit in which all of the upper stage side switching elements of the power conversion circuit 25 or all of the lower stage side switching elements are turned on, the maximum value of the phase current absolute value after execution of the three phase short circuit is If it is determined that the permanent magnet is not demagnetized and it is determined that the permanent magnet of the motor is not demagnetized, the three-phase short circuit is started. If it is determined that the permanent magnet of the motor is demagnetized, It is determined that the power supply side is abnormal.

  Hereinafter, the operation of the three-phase short circuit process command generation unit 67, which is a feature of the motor control device according to the first embodiment of the present invention, will be described in detail.

First, based on the DC bus voltage Vpn input from the voltage detection unit 24, the power supply abnormality determination unit 68 determines whether or not the power supply abnormality is such that regenerative power can not be regenerated to the DC power supply 90. This determination is output to the three-phase short circuit processing command generation unit 67 and the current command selection unit 69 as the power supply side abnormality determination result Err.
Specifically, when the DC bus voltage Vpn is equal to or higher than a predetermined set value, the power supply side abnormality determination unit 68 determines that the regenerative power can not be regenerated by the DC power supply 90 and is in the power supply side abnormal state. Otherwise, it is determined that the power supply side is normal.

  As a result, regenerative electric power is stored in the capacitor 21 by the motor 10 performing regenerative operation in the open state of the power switch 70, and the voltage across the capacitor 21, that is, the DC bus voltage is in a high voltage state that can not occur in normal operation. Or when the regenerative power can not be regenerated to the DC power supply 90, such as when the DC power supply 90 is in a high voltage state that can not occur in normal operation even when the power switch 70 is conductive. It can be determined that

  If the power supply abnormality determination unit 68 determines that the power supply abnormality determination result Err is in the power supply normal state, the motor 10 can be operated in power running and regenerative operation without any problem, and the three-phase short circuit processing command is generated. The unit 67 generates a three-phase short circuit non-execution command as the three-phase short circuit processing command S3PS, and outputs it to the PWM signal generation unit 66.

When the three-phase short circuit processing command S3PS is a three-phase short circuit non-execution command, the PWM signal generation unit 66 sets the duty command value Du of each phase by a triangular wave comparison method generally executed widely by inverter driving. It outputs an on / off control signal to each switching element according to Dv and Dw. In addition, since the triangular wave comparison method is known, detailed description will be omitted.
If the power supply abnormality determination unit 68 determines that the power supply abnormality determination result Err is in the power supply abnormality state, the three phase short circuit processing command generation unit 67 generates three phases as a three phase short circuit processing command S3PS by a method described later. A phase short circuit execution command is generated and output to the PWM signal generation unit 66.

When the three-phase shorting process command S3PS is a three-phase shorting execution command, the PWM signal generation unit 66 turns on the upper stage switching elements 31, 33, 35 and turns off the lower stage switching elements 32, 34, 36. The on / off control signal is output to the power conversion circuit 25.
Note that the PWM signal generation unit 66 may use the switching element that shorts three phases as the lower stage switching element, so that the upper stage switching elements 31, 33, 35 are turned off and the lower stage switching elements 32, 34, 36 are turned on. An on / off control signal may be output to the power conversion circuit 25.

  By the above-described operation, when the regenerative power can not be regenerated to the DC power supply 90, for example, when the inverter circuit 20 is disconnected from the DC power supply 90 during the regenerative operation of the motor 10, all or lower stages of upper stage switching elements of the inverter circuit 20 A three-phase short circuit is performed to turn on all the switching devices on the side and short the respective phases of the motor 10 to each other, thereby preventing the capacitor 21 from excessively regenerating the power and causing the capacitor terminal voltage to rise excessively. be able to.

Here, when the three-phase short circuit processing command generation unit 67 generates a three-phase short circuit execution command, the minimum value of the d-axis current after the three-phase short circuit processing is executed does not demagnetize the permanent magnet of the motor. A three-phase short circuit execution command is generated at the timing when

In the following, when it is determined that the power supply side abnormality determination result Err is in the power supply side abnormal state, that is, the three phase short circuit processing command S3PS is generated when the three phase short circuit execution command is generated by the three phase short circuit processing command generation unit 67. The method will be described in detail.
First, the timing at which the minimum value of the d-axis current after execution of the three-phase short circuit becomes the d-axis current value that does not demagnetize the permanent magnet of the motor will be described.

  Rare earth magnets, which are often used as permanent magnets for motors, are characterized by a large energy product, but it is well known that irreversible demagnetization occurs and their characteristics deteriorate when used in the area beyond the knick point. Since a large current is supplied to the exciting coil and a large demagnetizing field is applied to the magnet, the permanent magnet is demagnetized, so the magnetic flux in the d-axis direction usually applied to the permanent magnet does not exceed the predetermined value To be controlled.

ここで、Φｄは電動機のｄ軸方向磁束、Ｌｄは電動機のｄ軸インダクタンス、Φは電動機の永久磁石の磁束、ｉｄは電動機のｄ軸電流である。 In the drive of the motor, the d-axis direction magnetic flux Φ d acting on the permanent magnet is expressed by the following equation (1).

Here, Φ d is the d-axis direction magnetic flux of the motor, L d is the d-axis inductance of the motor, Φ is the magnetic flux of the permanent magnet of the motor, and id is the d-axis current of the motor.

  As shown in the equation (1), it is understood that the d-axis direction magnetic flux φ d depends on the d-axis current. The permanent magnet is demagnetized when the d-axis direction magnetic flux Φ d increases in the negative direction, and the case where the d-axis current is generated excessively in the negative direction corresponds to the condition for demagnetizing the permanent magnet. For this reason, the current command is set and controlled so that the d-axis current of the motor does not act in the negative direction above a predetermined current value. However, after execution of the three phase short circuit, all the upper side switching elements of the inverter circuit 20 or all the lower side switching elements are turned on to short each phase of the motor 10, so the d-axis current is less than a predetermined value. Current control is impossible. Therefore, in the conventional patent document 1, the d-axis current after the execution of the three-phase short circuit does not exceed a predetermined value by limiting the maximum torque in advance. However, in such a method, the maximum torque is excessively limited even in a normal operating condition, so that the desired torque which is desired to be output in the normal state may not be obtained.

  In the present invention, the maximum torque is not excessively restricted when the power supply side abnormality determination result Err is not determined, and the current command (final d axis current command value, final q) is determined when the power supply side abnormality determination result Err is determined. Command the axis current command value) in the direction in which the minimum value (maximum amplitude in the negative direction) of the d-axis current after the three-phase short circuit decreases. Then, when it is determined that the minimum value of the d-axis current (amplitude maximum value in the negative direction) after the three-phase short circuit becomes less than a predetermined value, the three-phase short circuit processing command is made effective to execute the three-phase short circuit. . In this way, it is possible to prevent the maximum torque of the motor from being excessively limited.

Next, an equation for obtaining the minimum value (maximum amplitude value in the negative direction) of the d-axis current after the three-phase short circuit used to determine that the d-axis current after the three-phase short circuit is less than a predetermined value will be described. . The minimum value (amplitude maximum value in the negative direction) of the d-axis current after the execution of the three-phase short circuit can be obtained from the d-axis current and the q-axis current flowing through the motor 10 before the three-phase short circuit.
More specifically, it can be obtained from the condition that the total magnetic flux Ψ of the motor 10 before and immediately after the three-phase short circuit is continuous.

ここで、Φは永久磁石の磁束、ｉｄ＿ｐｒｅは三相短絡処理前のｄ軸電流、Ｌｄは電動機１０のｄ軸インダクタンス、Ｌｑは電動機１０のｑ軸インダクタンス、ｉｑ＿ｐｒｅは三相短絡処理前のｑ軸電流である。 The total magnetic flux Ψ of the motor 10 before the three-phase short circuit is the following equation (2).

Here, Φ is the magnetic flux of the permanent magnet, id_pre is the d-axis current before the three-phase shorting process, Ld is the d-axis inductance of the motor 10, Lq is the q-axis inductance of the motor 10, iq_pre is the q-axis before the three-phase shorting process It is a current.

ここで、三相短絡後にｄ軸電流が最小値（負方向の振幅最大値）となるときのｄ軸電流をｉｄ＿３ｐｓとした。 Next, since the q-axis current becomes zero when the d-axis current becomes the minimum value immediately after the three-phase short circuit, the total magnetic flux Ψ of the motor 10 is expressed by the following equation (3).

Here, the d-axis current at which the d-axis current reaches the minimum value (the maximum value in the negative direction) after the three-phase short circuit is id_3 ps.

式（４）を変形することで、電動機１０の三相短絡後のｄ軸電流の最小値（負方向の振幅最大値）ｉｄ＿３ｐｓが次式（５）で求まる。

式（５）において、Φ、Ｌｄ、Ｌｑはモータの特性によって決まるため、その代表値はあらかじめ磁界解析や実機の測定によって容易に把握できる。三相短絡前の動作状態のおけるｉｄ＿ｐｒｅ、ｉｑ＿ｐｒｅの値は三相二相変換部６２からのｄ軸電流検出値Ｉｄおよびｑ軸電流検出値Ｉｑでわかるため、式（５）から電動機１０の動作状態における三相短絡後のｄ軸電流の最小値（負方向の振幅最大値）ｉｄ＿３ｐｓが逐次求めることが可能であることがわかる。 The condition in which the magnetic flux of the motor 10 becomes continuous before and immediately after the three-phase short circuit is the following equation (4).

By modifying the equation (4), the minimum value (maximum amplitude in the negative direction) id_3 ps of the d-axis current after the three-phase short circuit of the motor 10 can be obtained by the following equation (5).

In the equation (5), 、, Ld, and Lq are determined by the characteristics of the motor, so the representative values can be easily grasped in advance by magnetic field analysis or measurement of a real machine. Since the values of id_pre and iq_pre in the operating state before the three-phase short circuit can be known from the d-axis current detection value Id and the q-axis current detection value Iq from the three-phase two-phase converter 62, the operation of the motor 10 is It can be seen that the minimum value (maximum amplitude in the negative direction) id_3 ps of the d-axis current after the three-phase short circuit in the state can be determined sequentially.

FIG. 3 is a diagram showing the waveform of the d-axis current and the waveform of the q-axis current of the motor 10 immediately after the three-phase short circuit of the motor 10, and also shows the d-axis current value obtained by the equation (5) . At the moment when the q-axis current crosses zero, the d-axis current reaches its maximum value in the negative direction, and its size is approximately the same as id_3 ps obtained by equation (5).
Next, in current command selection unit 69, final d-axis current command value Id2 * and final q-axis current command value Iq2 when the power supply side abnormality determination result Err from power supply side abnormality determination unit 68 determines that the power supply side is abnormal. The method of generating * will be described.

From equation (5), the d-axis current before three-phase shorting is controlled to-電流 / Ld and the q-axis current becomes zero, so that the minimum value of d-axis current after three-phase shorting is controlled. (Amplitude maximum value in the negative direction) It can be seen that the absolute value of id_3 ps can be reduced.
Therefore, in the present invention, when it is determined that the power supply side abnormality determination result Err from the power supply side abnormality determination unit 68 in the current command selection unit 69 is the power supply side abnormality, the final d-axis current command value Id2 * is -Φ / Ld. , Final q-axis current command value Iq2 * is set to zero. By doing this, it is possible to control in such a direction that the absolute value of the minimum value (maximum amplitude value in the negative direction) id_3 ps of the d-axis current after the three-phase short circuit becomes surely smaller.

  In the present invention, after setting the final d-axis current command value Id2 * to -Φ / Ld and the final q-axis current command value Iq2 * to zero, the d-axis current detection values Id and q from the three-phase to two-phase converter 62 The minimum value (value at which the amplitude in the negative direction is maximum) id_3 ps of the d-axis current after the three-phase short circuit calculated from the axis current detection value Iq by equation (5) prevents the permanent magnet of the motor 10 from demagnetizing Irreversible demagnetization of the permanent magnet of the motor 10 can be prevented by making the three-phase short circuit effective at a timing that exceeds the d-axis current limit value Id_lim set in advance in the three-phase short circuit processing command generation unit 67.

The detailed processing of the three-phase short circuit processing command generation unit 67 will be described below with reference to the flowchart of FIG. 4.
First, in the first step S101, it is determined whether or not a three-phase short circuit is being performed. In the following, “step” is omitted and simply indicated by the symbol “S”.
If it is determined that the three-phase short circuit is being executed, that is, if it is determined YES in S101, the three-phase short circuit execution command is generated as the three-phase short circuit processing command S3PS to continue the three-phase short circuit state S105. Transition to

On the other hand, if it is determined that the three-phase short circuit is not being performed, that is, if it is determined NO in S101, the process proceeds to S102.
In S102, which is performed when it is determined that the three-phase short circuit is not being performed, it is determined whether the power supply side abnormality determination result Err is in the power supply side abnormal state.
If it is determined that the power supply side abnormality determination result Err is in the power supply side abnormal state, that is, if it is determined YES in S102, the process proceeds to S103.
If it is determined that the power supply side abnormality determination result Err is not the power supply side abnormality, that is, if it is determined NO in S102, it is not necessary to execute the three phase short circuit, and the three phase short circuit processing command S3PS is used. It transfers to S106 which produces | generates a phase short circuit non-execution command.

  In S103, in which the power supply side abnormality determination result Err is determined to be the power supply side abnormal state, in S103, the d-axis current detection value Id and the q-axis current detection value Iq input from the three-phase / two-phase conversion unit 62 The minimum value (amplitude maximum value in the negative direction) id_3 ps of the d-axis current after the three-phase short circuit is calculated by the equation (5), and the process proceeds to S104.

  The minimum value (value at which the amplitude in the negative direction becomes maximum) id_3 ps of the d-axis current after three-phase shorting determined by the equation (5) generates three-phase shorting command in advance so that the permanent magnet of the motor 10 is not demagnetized. If it is determined that the d-axis current limit value Id_lim set in section 67 is exceeded (the amplitude in the negative direction decreases), that is, if it is determined YES in S104, the d-axis current after execution of the three-phase short circuit Since the minimum value of is the timing at which the d-axis current value does not demagnetize the permanent magnet of the motor, the process proceeds to S105 where a three-phase short circuit execution command is generated as the three-phase short circuit processing command S3PS.

  If it is determined that the minimum value of d-axis current after execution of the three-phase short circuit processing is not the d-axis current value that does not demagnetize the permanent magnet of the motor, that is, if it is determined NO in S104, after execution of the three phase short circuit Since the minimum value of the d-axis current in the above does not become the d-axis current value that does not demagnetize the permanent magnet of the motor, the process proceeds to S106 where a three-phase short circuit non-execution command is generated as the three phase short circuit processing command S3PS.

  When it is determined that the power supply side abnormality determination result Err is in the power supply side abnormal state by the processing shown in the above flowchart, that is, when the three phase short circuit processing command generation unit 67 generates a three phase short circuit execution command, The three-phase short circuit execution command can be generated at such a timing that the minimum value of the d-axis current after the execution of the short circuit becomes the d-axis current value that does not demagnetize the permanent magnet of the motor. That is, when performing a three-phase short circuit, the three-phase short circuit can be started at a timing when the minimum value of the d-axis current after the execution of the three phase short becomes a d-axis current value that does not demagnetize the permanent magnet of the motor. .

  As described above, according to the first embodiment, when performing the three-phase short circuit, the minimum value of the d-axis current after the execution of the three-phase short circuit is the d-axis current value that does not demagnetize the permanent magnet of the motor 10 Since the three-phase short circuit can be started based on the d-axis current and the q-axis current, it becomes possible to make the motor permanent by the transient current generated when the motor power line is short-circuited. Irreversible demagnetization of the magnet can be prevented, and torque reduction due to demagnetization of the permanent magnet of the motor can be prevented. Further, since the excessive maximum torque is not suppressed in the state where the power supply side abnormality determination result Err is determined not to be the power supply side abnormal state, the desired required torque can be output from the motor when the power supply is normal.

  Thereby, when the motor control device according to the present invention is applied to an electric vehicle, it becomes possible to obtain desired acceleration / deceleration characteristics, and after the power supply side abnormality determination result Err is determined to be a power supply side abnormal state, three. When the phase short circuit is performed, demagnetization of the permanent magnet of the motor 10 can be prevented.

  In addition, since the minimum value of the d-axis current after execution of the three-phase short circuit does not cause the permanent magnet of the motor 10 to be demagnetized, the d-axis current value uses a simple equation such as the above equation (5). It is not necessary to obtain in advance the finite element method for the set of the irreversible demagnetization current value and the transient current generated at the time of the three phase short circuit corresponding to There is also an advantage that man-hours for setting and adjusting the control can be reduced since there is no

  In addition, since the minimum value of the d-axis current after execution of the three-phase short circuit does not cause the permanent magnet of the motor 10 to be demagnetized, the d-axis current value uses a simple equation such as the equation (5). It is not necessary to create a huge table in the above, or to store a huge amount of data in a memory, and it is possible to configure with an arithmetic device whose memory capacity is not sufficient. As a result, even in a motor control device using an inexpensive arithmetic device having insufficient memory capacity, generation of irreversible demagnetization can be prevented and the arithmetic device can be configured at low cost, so the motor control device is provided at low cost. It is possible.

  In the first embodiment, the three-phase short circuit processing command generation unit 67 calculates the d-axis current value at which the minimum value of the phase d-axis current after execution of the three-phase short does not demagnetize the permanent magnet of the motor 10. Although the processing is performed using the above equation (5) as the processing, the present invention is not particularly limited to this equation as long as the operation method is essentially the same.

  In the first embodiment, when the current command value selection unit 69 determines that the power supply side is in an abnormal state, the final d-axis current command value Id2 * and the final q-axis current command value Iq2 * The command value Id * is switched to -− / Ld, and the q-axis current command value Iq * is switched to 0. However, the present invention is not particularly limited to this formula as long as the calculation method is essentially the same. That is, the d-axis current command value and the q-axis are set so as to reduce the minimum value of the d-axis current after execution of the three-phase short, that is, to decrease the maximum amplitude in the negative direction of the minimum value of the d-axis current. The present invention is not particularly limited to this equation as long as the current command value is changed.

  Further, in the first embodiment, the power supply side abnormality determination unit 68 of the switching control unit 60 determines whether or not the power supply side abnormality state is present based on the DC bus voltage information input from the voltage detection unit 24. In the other configuration, for example, the open state of the power switch 70 is communicated from an external control device (not shown) such as a vehicle ECU, and the power switch 70 is in the open state, and thus the power supply side is abnormal. It may be determined that

  Further, as a switching element of the power conversion circuit 25, any element may be used, but for example, a wide band gap semiconductor can be used. As a wide band gap semiconductor, what was formed, for example with silicon carbide, gallium nitride system material, diamond, etc. is mentioned. A wide band gap inverter formed of a switching element formed of such a wide band gap semiconductor has a high withstand voltage, as compared with a Si inverter formed of a conventional switching element formed of Si (silicon), It is characterized by low loss and high frequency drive.

Second Embodiment
Next, a motor control device according to a second embodiment of the present invention will be described in detail based on FIG. 5 to FIG. The motor control device according to the second embodiment is configured of an inverter circuit 20 and a switching control unit 60, as in the system configuration shown in FIG. 1 of the first embodiment. However, the second embodiment is different from the first embodiment in the functional block configuration of switching control unit 60 and in the processing of three-phase short circuit processing generation unit 67. ing. Therefore, this difference will be mainly described below.

  FIG. 5 is a functional block diagram of the switching control unit 60 in the second embodiment of the present invention. As shown in FIG. 5, in the functional block of switching control unit 60 according to the second embodiment, compared to the functional block diagram shown in FIG. With respect to 67, the only difference is that the input of the DC bus voltage Vpn from the voltage detection unit 24 is added.

Further, the method of generating the three-phase short circuit processing command S3PS in the three-phase short circuit processing command generation unit 67 is different from that of the first embodiment. Other configurations and operations are the same as those of the first embodiment, and therefore, the description of the same or corresponding parts as those of the first embodiment is omitted, and a three-phase short circuit different from the first embodiment is described. The process command generation unit 67 will be described in detail.
The three-phase short process command generation unit 67 according to the second embodiment detects the d-axis current detection value Id and the q-axis current detection value Iq from the three-phase two-phase conversion unit 62, the DC bus voltage Vpn from the voltage detection unit 24, and the power supply side. The power source side abnormality determination result Err is input from the abnormality determination unit 68, and a three-phase short circuit processing command S3PS is generated based on these.

  Specifically, when it is determined that the power supply side abnormality determination result Err is in the power supply normal state, the three-phase short circuit processing command generation unit 67 sets the three-phase short circuit non-execution command as the three-phase short circuit processing command S3PS. If it is determined that the power supply side abnormality determination result Err is determined to be the power supply side abnormal state, a three-phase shorting process is performed based on the d-axis current detection value Id, the q-axis current detection value Iq and the DC bus voltage Vpn. A three-phase short circuit execution command is generated as a command S3PS.

  Here, the feature of the motor control device according to the second embodiment of the present invention is that the switching control unit 60 is provided with a three-phase short circuit processing command generation unit 67 and a current command selection unit 69 to When it is determined that there is a final d-axis current command value Id2 * and a final q-axis current command value Iq2 *, the d-axis current command value Id * is -Φ / Ld and the q-axis current command value Iq * is 0. At the same time as switching, a three-phase short circuit execution command is generated based on the d-axis current detection value Id, the q-axis current detection value Iq, and the DC bus voltage Vpn to execute the three-phase short circuit.

  With this configuration, as described later, when performing the three-phase short circuit after the abnormality determination of the power supply side abnormality determination unit 68, the minimum value of the d-axis current after the three-phase short circuit execution demagnetizes the permanent magnet of the motor A three-phase short circuit can be started at a timing when the d-axis current value does not occur. Further, it is possible to generate a three-phase short circuit execution command so as to prevent destruction of the motor control device when the DC voltage is unexpectedly excessive.

The detailed processing of the three-phase short circuit processing command generation unit 67 will be described below with reference to the flowchart of FIG.
First, in the first step S201, it is determined whether or not a three-phase short circuit is being performed. In the following, “step” is omitted and simply indicated by the symbol “S”.
If it is determined that the three-phase short circuit is being executed, that is, if it is determined YES in S201, the three-phase short circuit execution command is generated as the three-phase short circuit processing command S3PS to continue the three-phase short circuit state S205 Transition to

On the other hand, if it is determined that the three-phase short circuit is not being executed, that is, if it is determined NO in S201, the process proceeds to S202.
In S202, in which it is determined that the three-phase short circuit is not being executed, it is determined whether the power supply side abnormality determination result Err is in the power supply side abnormal state.
If it is determined that the power supply side abnormality determination result Err is in the power supply side abnormal state, that is, if it is determined YES in S202, the process proceeds to S203.
If it is determined that the power supply side abnormality determination result Err is not the power supply side abnormal state, that is, if it is determined NO in S202, there is no need to execute the three phase short circuit, and the three phase short circuit processing command S3PS is used. It transfers to S206 which produces | generates a phase short circuit non-execution command.

  In S203, in which the power supply side abnormality determination result Err is determined to be the power supply side abnormal state, in S203, from the d-axis current detection value Id and the q-axis current detection value Iq input from the three-phase to two-phase converter 62, The minimum value (amplitude maximum value in the negative direction) id_3 ps of the d-axis current after the three-phase short circuit is calculated by the equation (5), and the process proceeds to S204.

  The minimum value (value at which the amplitude in the negative direction becomes maximum) id_3 ps of the d-axis current after three-phase shorting determined by the equation (5) generates three-phase shorting command in advance so that the permanent magnet of the motor 10 is not demagnetized. When it is determined that the d-axis current limit value Id_lim set in the section 67 is exceeded (the amplitude in the negative direction decreases), or it is determined that the DC voltage Vpn exceeds the DC voltage limit value Vpn_lim set in advance. In the case where the determination is YES in S204, that is, when the three-phase short circuit processing command S3PS is determined to be YES, the process proceeds to S205 in which a three-phase short circuit execution command is generated. When the former is determined, it is the timing at which the minimum value of the d-axis current after execution of the three-phase short circuit becomes the d-axis current value that does not demagnetize the permanent magnet of the motor. In the latter case, it is determined that the DC voltage Vpn is larger than the preset DC voltage limit value Vpn_lim, and priority is given to preventing the motor control device from breaking due to high voltage generation rather than the demagnetization of the permanent magnet. Timing to operate the three-phase short circuit.

  When it is determined that the minimum value of the d-axis current after the three-phase shorting process is not not the d-axis current value that does not demagnetize the permanent magnet of the motor, and the DC voltage Vpn is from the DC voltage limit value Vpn_lim set in advance. If it is determined to be small, that is, if it is determined NO in S204, the minimum value of the d-axis current after execution of the three-phase short does not become the d-axis current value that does not demagnetize the permanent magnet of the motor. Since the DC voltage Vpn is also equal to or less than the DC voltage limit value Vpn_lim, the process proceeds to S206 in which a three-phase short circuit non-execution command is generated as the three-phase short circuit processing command S3PS.

  When it is determined that the power supply side abnormality determination result Err is in the power supply side abnormal state by the processing shown in the above flowchart, that is, when the three phase short circuit processing command generation unit 67 generates a three phase short circuit execution command, The three-phase short circuit execution command can be generated at such a timing that the minimum value of the d-axis current after the execution of the short circuit becomes the d-axis current value that does not demagnetize the permanent magnet of the motor. That is, when performing a three-phase short circuit, the three-phase short circuit can be started at a timing when the minimum value of the d-axis current after the execution of the three phase short becomes a d-axis current value that does not demagnetize the permanent magnet of the motor. . Also, when it is determined that the DC voltage Vpn is the DC voltage limit value Vpn_lim set in advance, the three-phase short circuit execution command can be generated as the three-phase short circuit processing command S3PS. That is, it is possible to generate a three-phase short circuit execution command so as to prevent the motor control device from being broken when the DC voltage is unexpectedly excessive. Specifically, when it is determined that the DC voltage exceeds the preset DC voltage upper limit value, the minimum value of the d-axis current after the execution of the three-phase short circuit does not demagnetize the permanent magnet of the AC motor. Regardless of whether it is determined or not, a three-phase short circuit is initiated.

  As described above, according to the second embodiment, when performing the three-phase short circuit, the minimum value of the d-axis current after the execution of the three-phase short circuit is the d-axis current value that does not demagnetize the permanent magnet of the motor 10 Since the three-phase short circuit can be initiated based on the d-axis current, the q-axis current, and the DC voltage, the transient current generated when the motor power line is three-phase shorted can be determined. Irreversible demagnetization of the permanent magnet of the motor due to the above can be prevented, and torque reduction due to demagnetization of the permanent magnet of the motor can be prevented. Further, since the excessive maximum torque is not suppressed in the state where the power supply side abnormality determination result Err is determined not to be the power supply side abnormal state, the desired required torque can be output from the motor when the power supply is normal. Furthermore, in the case where the DC voltage is unexpectedly excessive, it is possible to operate with priority given to the prevention of destruction due to high voltage generation of the motor control device over demagnetization of the permanent magnet.

Thereby, when the motor control device according to the present invention is applied to an electric vehicle, it becomes possible to obtain desired acceleration / deceleration characteristics, and after the power supply side abnormality determination result Err is determined to be a power supply side abnormal state, three. When the phase short circuit is performed, demagnetization of the permanent magnet of the motor 10 can be prevented.
The first and second embodiments described above are merely examples, and the present invention is not limited to the first and second embodiments if they can be applied. For example, in the first and second embodiments, the DC power supply 90 and the motor control device 80 are directly connected. However, a DC / DC converter may be disposed between the DC power supply 90 and the motor control device 80 to perform boosting and bucking operations. In addition, it may be configured to be connected to an AC power supply via a rectifier that converts AC power of the AC power supply to DC power or an AC / DC converter.

In the first and second embodiments, the application to an electric vehicle has been described as an example, but the present invention may be applied to a hybrid vehicle that uses an engine and a motor in combination. Furthermore, the application of the motor control device according to the present invention is not limited to the vehicle.
As described above, the present invention is not limited to the first and second embodiments, and various design changes can be made. Within the scope of the present invention, each of the first and second embodiments can be modified. It is possible to freely combine, or modify and omit the first and second embodiments as appropriate.

1a, 1b DC bus, 2 AC bus, 10 motors, 20 inverter circuits,
21 capacitor 24 voltage detection unit 25 power conversion circuit 26 motor current detection unit
30 rotation angle sensor (rotational speed detector), 31 to 36 switching elements,
60 switching controller, 61 current command generator, 62 three-phase to two-phase converter,
63 current controller, 64 two-phase three-phase converter, 65 duty converter,
66 PWM signal generation unit, 67 three-phase short circuit processing instruction generation unit, 68 power supply side abnormality determination unit,
69 Current command selection unit, 70 power switch, 80 motor controller, 90 DC power supply,
100 d-axis current command generator at fault, q-axis current command generator at 101 fault,
102 selector switch.

Claims (12)

  A motor control device connected between a DC power supply and an AC motor for converting DC power of the DC power supply into AC power to drive and control the AC motor, wherein an arm is an upper stage switching element and a lower stage switching element And a switching control unit for performing on / off control of switching elements of the power conversion circuit, wherein the switching control unit is all of the upper stage switching elements or the lower stage switching elements And a determination unit that determines whether the minimum value of the d-axis current after the execution of the three-phase short circuit does not demagnetize the permanent magnet of the motor when the three-phase short circuit is performed to turn on all of A three-phase short circuit processing command generation unit that generates and outputs a three-phase short circuit processing command that starts the three-phase short circuit when it is determined that demagnetization is not performed Motor control device characterized in that it has.   The switching control unit prevents the minimum value of the d-axis current after execution of the three-phase short circuit from demagnetizing the permanent magnet of the AC motor based on the d-axis current detection value and the q-axis current detection value of the AC motor. The motor control device according to claim 1, wherein it is determined whether or not it is.   The switching control unit calculates the minimum value of the d-axis current after execution of the three-phase short circuit by calculation, and the minimum value of the d-axis current after execution of the three-phase short circuit does not demagnetize the permanent magnet of the AC motor The motor control device according to claim 2, wherein it is determined whether or not it is.   The switching control unit performs the three-phase short circuit after the minimum value of the d-axis current exceeds the d-axis current limit value set in advance so that the permanent magnet of the AC motor does not demagnetize. The motor control device according to claim 3, wherein it is determined that the minimum value of the d-axis current does not demagnetize the permanent magnet of the motor. The switching control unit generates the following equation based on the d-axis current detection value and the q-axis current detection value flowing to the AC motor.

(However, id_3 ps: Minimum value of d-axis current after three-phase short circuit in motor operating condition, Φ: magnetic flux of permanent magnet, id_pre: d-axis current before three-phase short circuit treatment, Ld: d-axis inductance of motor, Lq: q-axis inductance of motor, iq_pre: q-axis current before treatment of three-phase short circuit)
The motor control device according to claim 3 or 4, wherein the minimum value of the d-axis current after execution of the three-phase short circuit is determined by   When the three-phase short circuit is performed, the switching control unit is configured to set the d-axis current command value so that the maximum amplitude in the negative direction of the minimum value of the d-axis current after the three-phase short circuit is reduced. The motor control device according to any one of claims 1 to 5, wherein the q-axis current command value is changed.   The switching control unit changes the d-axis current command value and the q-axis current command value so as to approach the d-axis current value and the q-axis current value after execution of a three-phase short circuit. The motor control device according to 6.   When the three-phase short circuit is performed, the switching control unit changes the d-axis current command value to-電流 / Ld, and changes the q-axis current command value to zero. The motor control device according to or 7.   When the switching control unit determines that the DC voltage exceeds the preset DC voltage upper limit value, the minimum value of the d-axis current after execution of the three-phase short circuit reduces the permanent magnet of the AC motor. The motor control device according to any one of claims 1 to 8, wherein the three-phase short circuit is started regardless of the determination as to whether or not to cause the magnetizing.   The switching control unit has a power supply abnormality determination unit that determines whether there is a power supply abnormality state in which regeneration power from the AC motor can not be regenerated to the DC power supply, and the power supply abnormality determination unit The motor control device according to any one of claims 1 to 9, wherein control of the processing of the three-phase short circuit is started when it is determined that the power supply side is in an abnormal state.   The motor control device according to any one of claims 1 to 10, wherein the switching element forming the power conversion circuit is formed of a wide band gap semiconductor.   An arm is connected between a DC power supply and an AC motor, and an arm is constituted by a series circuit of an upper stage switching element and a lower stage switching element, and a DC current is obtained by on / off controlling the upper stage switching element and the lower stage switching element. In the control of drive and regeneration of the AC motor of a motor control device including a power conversion circuit that performs power conversion with three-phase alternating current, and a switching control unit that performs on / off control of switching elements that configure the power conversion circuit, Whether the minimum value of the d-axis current after the execution of the three-phase short circuit does not demagnetize the permanent magnet of the motor when the three-phase short circuit is performed to turn on all the upper stage switching elements or all the lower stage switching elements If it is determined that the permanent magnet of the motor is not to be demagnetized, the three-phase short circuit is started. Motor control method comprising and.

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