TWI618344B - Motor control - Google Patents

Abstract

The object of the present invention is to realize a motor control device that improves torque reduction during high-speed load rotation during power operation of a magnetically saturated motor and reduces acceleration time, and also suppresses excessive torque during motor regeneration to prevent replacement. The overvoltage of the current transformer and the overcurrent of the converter, and there is no rapid change of the torque constant, which can take into account good acceleration characteristics and safe deceleration characteristics. The power running / regeneration discriminator determines the power running / regeneration status of the motor using the torque current command and the motor rotation speed. The limiter allows the torque current command to pass when the motor is in a power running state, and limits the magnitude of the torque current command to allow it to pass during a regeneration state. The field current command calculator recognizes the rotation state of the motor by using the rotation speed of the motor, and calculates a field current command corresponding to the rotation state. The motor drive unit (q-axis current controller, d-axis current controller, coordinate converter, PWM controller, power converter) drives the motor using the torque current command passed through the limiter and the calculated exciting current command.

Description

Motor control Field of invention

The present invention relates to a motor control device that improves the acceleration and deceleration characteristics of vector control of an induction motor.

Background of the invention

The machine tool spindle is expected to be able to balance both low-speed heavy cutting and high-speed cutting. Therefore, constant output control based on field weakening is used to achieve high torque and high speed rotation during low speed rotation. The motor control device that performs constant output control is configured as follows, for example.

FIG. 12 is a block diagram of a conventional motor control device. This motor control device performs the following operations.

First, the speed command is compared with the motor rotation speed ωm from the speed calculator 15, and the q-axis current command IqC is obtained by the speed controller 20. The motor rotation speed ωm output from the speed calculator 15 is calculated using position feedback detected by the encoder 10. The q-axis current command IqC is compared with the q-axis current feedback IqF from the coordinate converter 25, and the q-axis voltage command VqC is obtained by the q-axis current controller 30.

On the other hand, referring to the motor rotation speed ωm, the necessary magnetic flux is issued with the magnetic flux command φ2C, and the magnetic flux command φ2C and the magnetic flux are calculated. The magnetic flux φ2 obtained by the calculator 35 is compared, and the d-axis current command IdC is obtained by the magnetic flux controller 40. The magnetic flux φ2 output from the magnetic flux calculator 35 is calculated using the d-axis current feedback IdF from the coordinate converter 25. The d-axis current command IdC is compared with the d-axis current feedback IdF from the coordinate converter 25, and the d-axis voltage command VdC is obtained by the d-axis current controller 45.

The slip frequency calculator 50 calculates a slip frequency command ωs from the q-axis current command IqC and the magnetic flux φ2. The slip frequency command ωs is added to the motor rotation speed ωm output from the speed calculator 15. A primary frequency command ω1 is obtained from the slip frequency command ωs and the motor rotation speed ωm. The integrator 55 integrates the primary frequency command ω1 to obtain the stator position command θmc.

The coordinate converter 60 performs coordinate conversion on the q-axis voltage command VqC and the d-axis voltage command VdC based on the stator position command θmc to obtain three-phase voltage commands Vuc, Vvc, and Vwc. The three-phase voltage commands Vuc, Vvc, and Vwc are supplied to the motor 80 through the PWM controller 65 and the power converter 70. The motor 80 is driven in response to the three-phase voltage commands Vuc, Vvc, and Vwc.

The q-axis current feedback IqF and the d-axis current feedback IdF are obtained by coordinate conversion of the motor currents Iu and Iv based on the stator position command θmc.

The magnetic flux command φ2C is as shown in the graph of FIG. 12. It is constant in the constant torque area and decreases in inverse proportion to the increase in the rotation speed of the motor 80 in the constant output area. The magnetic field weakening control is performed by decreasing the magnetic flux command φ2C in inverse proportion to the increase in the rotation speed of the motor 80.

In order to shorten the machining time, the spindle of a machine tool for tapping is desired to have a small spindle motor with small inertia and high-speed rotation. If Realizing the miniaturization and low inertia of the motor and designing the magnetic flux density of the iron core of the motor to be very high, there will be a failure to ensure sufficient magnetic flux due to the saturation of the iron core during high-speed and high-load rotation during power operation. The large torque causes a long acceleration time.

In order to improve this, it can be considered to increase the magnetic flux during high-speed rotation. In this case, there is a problem that the torque at the time of deceleration of the motor becomes excessively larger than that at the time of acceleration. When the motor decelerates, the regenerative power of the motor makes the DC voltage of the power converter higher, the voltage applied to the motor becomes higher, and the saturation of the iron core is relaxed, so a large torque is output. Because excessive torque can adversely affect the mechanical system, it is expected to be included in the specification. In addition, if the torque at the time of deceleration is too large, the regenerative power will increase, which may exceed the regenerative power allowed by the motor control device. A motor control device that consumes regenerative power with a resistor has a problem that the DC voltage of the inverter rises and becomes an overvoltage. In addition, the motor control device that returns the regenerative power to the power supply has a problem that the current of the inverter increases and becomes overcurrent.

In order to improve these problems, the invention described in Patent Document 1 below is to change the magnetic flux command during power operation and during regeneration.

Advance technical literature Patent literature

Patent Document 1 Japanese Patent No. 4065903

Summary of invention

However, when the invention described in Patent Document 1 is used, In the case, there are the following problems: If the magnetic flux command is changed during power operation and regeneration, the magnetic flux changes rapidly and the torque constant changes during the transition from power operation to regeneration. In the case of output torque, the output torque of the motor changes rapidly. And impulse to the mechanical system.

The present invention is an invention constructed to solve the problem of the conventional motor control device as described above, and an object thereof is to provide a motor control device that improves the torque reduction at the time of high-speed load rotation during the power operation of a magnetically saturated motor Shorten the acceleration time, at the same time suppress the excessive torque during motor regeneration, and prevent the over-voltage of the inverter and the over-current of the inverter, and there is no rapid change in torque constant, which can take into account good acceleration characteristics and safe deceleration characteristics.

In order to achieve the above object, a motor control device related to the present invention includes a power operation / regeneration discriminator, a limiter, an exciting current command calculator, and a motor driving unit.

The power running / regeneration discriminator determines the power running / regeneration status of the motor using the torque current command and the motor rotation speed. The limiter allows the torque current command to pass when the motor is in a power running state, and limits the magnitude of the torque current command to allow it to pass when the motor is in a regenerative state. The field current command calculator recognizes the rotation state of the motor by using the rotation speed of the motor, and calculates a field current command corresponding to the rotation state. The motor drive unit drives the motor using a torque current command passed through the limiter and a calculated excitation current command.

According to the motor control device related to the present invention configured as described above, the torque at the time of high-speed load rotation during power operation of a magnetically saturated motor is reduced to reduce the acceleration time, and at the same time, the excessive torque at the time of motor regeneration is suppressed, And to prevent the over-voltage of the converter and the over-current of the converter, and there is no rapid change in torque constant, it can take into account both good acceleration characteristics and safe deceleration characteristics.

10, 110, 210, 310‧‧‧ encoder

15, 115, 215, 315‧‧‧speed calculator

20‧‧‧speed controller

25, 125, 225, 325‧‧‧ coordinate converter

30, 130, 230, 330‧‧‧q axis current controller

35, 235, 335‧‧‧ magnetic flux calculator

40, 240, 340‧‧‧ magnetic flux controller

45, 145, 245, 345‧‧‧d-axis current controller

50, 150, 250, 350‧‧‧Slip frequency calculator

55, 155, 255, 355‧‧‧ integrator

60, 160, 260, 360‧‧‧ coordinate converter

65, 165, 265, 365‧‧‧PWM controller

70, 170, 270, 370‧‧‧ power converters

80, 180, 280, 380‧‧‧ Motor

100, 200, 300‧‧‧ Motor control device

135‧‧‧Excitation current command calculator

157, 257, 357‧‧‧‧OSC

175, 275, 375‧‧‧ Power operation / regeneration discriminator

185, 285‧‧‧q axis current limit calculator

190, 290, 390‧‧‧ Limiter

220, 320‧‧‧ magnetic flux instruction calculator

383‧‧‧Maximum primary current command calculator

385‧‧‧torque limiter

395‧‧‧q-axis current calculator

FIG. 1 is a block diagram of a motor control device according to the first embodiment.

FIG. 2 is a diagram showing a determination method of power operation and regeneration of the power operation / regeneration discriminator of FIG. 1. FIG.

FIG. 3 is a diagram showing the relationship between the motor rotation speed ωm of the q-axis current limit value calculator and the q-axis current command limit value IqLIM in FIG. 1.

FIG. 4 is a diagram showing the relationship between the motor rotation speed ωm of the field current command calculator of FIG. 1 and the field current command IdCB before the magnetic field is weakened.

FIG. 5 is a diagram showing the relationship between the motor rotation speed ωm of the exciting current command calculator and the exciting current command IdC in FIG. 1.

Fig. 6 is a block diagram of a motor control device according to a second embodiment.

FIG. 7 is a diagram showing the relationship between the motor rotation speed ωm of the q-axis current limit value calculation unit in FIG. 6 and the magnetic flux command φ2CB before the magnetic field is weakened.

FIG. 8 is a diagram showing the relationship between the motor rotation speed ωm and the magnetic flux command φ2C of the q-axis current limit value calculation unit in FIG. 6.

Fig. 9 is a block diagram of a motor control device according to a third embodiment.

FIG. 10 shows the power operation and the power operation / regeneration discriminator of FIG. 9 and FIG. Diagram of the discrimination method of reproduction.

FIG. 11 is a diagram showing the relationship between the motor rotation speed ωm of the maximum primary current command calculator and the maximum primary current command IPC of FIG. 9.

FIG. 12 is a block diagram showing an example of a conventional motor control device.

Forms used to implement the invention

The motor control device related to the present invention is to improve the low torque during high-speed load rotation during the power running of a magnetically saturated motor to reduce the acceleration time, and also to suppress the excessive torque when the motor is regenerated, thereby preventing the inverter from being damaged. Over-voltage and over-current of the inverter, and there is no rapid change of torque constant, taking into account good acceleration characteristics and safe deceleration characteristics. That is, the motor control device related to the present invention improves the acceleration and deceleration characteristics of the motor.

Next, the embodiments of the motor control device related to the present invention that exhibit the above-mentioned characteristics will be described with reference to the drawings, and will be described as [Embodiment 1] to [Embodiment 3].

[Embodiment 1]

[Overall Structure of Motor Control Device 100]

FIG. 1 is a block diagram of a motor control device 100 according to the first embodiment.

The motor control device 100 includes a q-axis current controller 130, a power operation / regeneration discriminator 175, a q-axis current limit value calculator 185, and a limiter 190 as a system that issues a q-axis voltage command VqC.

Power running / regeneration discriminator 175 is commanded by torque current IqCB and the motor rotation speed ωm determine whether the motor 180 is in a power running state or a regeneration state. The motor rotation speed ωm is output from the speed calculator 115. The speed calculator 115 calculates the motor rotation speed ωm using the position feedback detected by the encoder 110. Incidentally, the detailed operation of the power operation / regeneration discriminator 175 will be described later.

The q-axis current limit value calculator 185 calculates a q-axis current limit value IqLIM from the power operation and regeneration determination result of the power operation / regeneration discriminator 175 and the motor rotation speed ωm. Incidentally, the detailed operation of the q-axis current limit value calculator 185 will be described later.

The limiter 190 inputs the q-axis current limit value IqLIM calculated by the q-axis current limit value calculator 185, and limits the value of the torque current command IqCB. Incidentally, the detailed operation of the limiter 190 is described later.

The q-axis current limiter 130 calculates a q-axis voltage command VqC by subtracting a q-axis current feedback IqF from a q-axis current command IqC input through the limiter 190. The q-axis current feedback IqF is output by the coordinate converter 125. The q-axis current feedback IqF is obtained by performing coordinate conversion on the motor currents Iu and Iv based on a stator position command θmc described later. The q-axis current controller 130 is configured as a proportional-integral controller.

The motor control device 100 includes a magnetic flux current command calculator 135 and a d-axis current controller 145 as a system for issuing a d-axis voltage command VdC.

The excitation current command calculator 135 is inputting the motor rotation speed ωm, and calculates the optimal q-axis power for improving the acceleration and deceleration characteristics of the motor 180. Flow instruction IdC. Incidentally, the detailed operation of the exciting current command calculator 135 will be described later.

The d-axis current controller 145 calculates the d-axis voltage command VdC by inputting a current deviation obtained by subtracting the d-axis current feedback IdF from the q-axis current command IdC output from the exciting current command calculator 135. The d-axis current feedback IdF is output by the coordinate converter 125. The d-axis current feedback IdF is obtained by performing coordinate conversion on the motor currents Iu and Iv based on the stator position command θmc described later. The d-axis current controller 145 is configured as a proportional-integral controller.

The motor control device 100 includes a slip frequency calculator 150, an integrator 155, an OSC157, and coordinate converters 125 and 160 as a system for performing coordinate conversion.

The slip frequency calculator 150 inputs the q-axis current command IqC and the d-axis current command IdC output from the exciting current command calculator 135 to calculate the slip frequency command ωs. Incidentally, the detailed operation of the slip frequency calculator 150 will be described later.

The integrator 155 is a primary frequency command ω1 obtained by adding the slip frequency command ωs output by the slip frequency calculator 150 and the motor rotation speed ωm output by the speed calculator 115, and integrating the primary frequency command ω1 to obtain it. Stator position command θmc. The stator position command θmc is output to the coordinate converters 125 and 160 through OSC157.

The coordinate converter 160 performs coordinate conversion on the q-axis voltage command VqC and the d-axis voltage command VdC based on the input stator position command θmc to obtain three-phase voltage commands Vuc, Vvc, and Vwc.

The coordinate converter 125 performs coordinate conversion on the motor currents Iu and Iv based on the input stator position command θmc, and obtains q-axis current feedback IqF and d-axis current feedback IdF.

The motor control device 100 includes a PWM controller 165 and a power converter 170 as a system for driving the motor 180. Incidentally, the motor driving unit is formed by the PWM controller 165, the power converter 170, the q-axis current controller 130, the d-axis current controller 145, and the coordinate converter 160.

The PWM controller 165 inputs the three-phase voltage commands Vuc, Vvc, and Vwc output by the coordinate converter 160, and outputs a PWM signal for switching the power converter 170 based on the input three-phase voltage commands Vuc, Vvc, and Vwc.

The power converter 170 inputs a PWM signal output from the PWM controller 165, switches a semiconductor switching element included therein, and drives the motor 180.

[Operation of Power Operation / Regeneration Discriminator 175]

As described above, the power running / regeneration discriminator 175 determines whether the motor 180 is in a power running state or a regeneration state based on the torque current command IqCB and the motor rotation speed ωm.

The determination of power running and regeneration is made by considering the speed ripple caused by the loss of the motor 180 and the quantization error of the encoder 110 as shown in FIG. 2 using the motor rotation speed threshold ωA and the torque current command threshold IqA. The motor rotation speed threshold ωA is determined in consideration of the quantization error of the encoder 110, so that the power running and regenerative determination results do not occur during the no-load running of the motor 180. Chattering. The torque current command threshold IqA is determined in consideration of the loss of the motor 180, and is set to a value of the torque current command IqCB when the regenerative power of the motor 180-motor loss = 0.

The power running / regeneration discriminator 175 is shown in FIG. When conditions ≧ ωA and IqCB ≦ -IqA, or ωm ≦ -ωA and IqCB ≧ IqA, it is determined to be in a regeneration state, and in conditions other than these conditions, it is determined to be in a power running state.

[Operation of q-axis current limit value calculator 185]

As described above, the q-axis current limit value calculator 185 calculates the q-axis current limit value IqLIM from the power operation and regeneration determination result of the power operation / regeneration discriminator 175 and the motor rotation speed ωm. Specifically, the q-axis current limit value calculator 185 does not limit the q-axis current IqC in the case of the power running state, and limits the q-axis current IqC as shown in FIG. 3 in the case of the regeneration state.

q-axis current command limit value IqLIM = Iqmax

(When 0 ≦ | ωm | ≦ ω1)

q-axis current limit value IqLIM = Iqmax-KLIM. (| ωm | -ω1)

(when ω1 <| ωm |)

Here, ω1: the limit of the q-axis current starts the rotation speed

ω1 is a value higher than the base speed, and is adjusted based on the torque characteristics when the motor 180 is decelerated.

KLIM: Coefficient that determines the reduction amount of the q-axis current command limit value during high-speed rotation

[Action of Limiter 190]

As described above, the limiter 190 is a unit that calculates the q-axis current limit value calculator 185 The calculated q-axis current limit value IqLIM is input to limit the value of the torque current command IqCB. The limiter 190 obtains the q-axis current command Iqc after the limitation through the torque current command IqCB.

[Operation of the field current command calculator 135]

As described above, the field current command calculator 135 calculates an optimal field current command IdC for improving the acceleration / deceleration characteristics of the motor 180.

FIG. 4 is a diagram showing the relationship between the motor rotation speed ωm of the field current command calculator 135 of FIG. 1 and the field current command IdCB before the magnetic field is weakened. The exciting current command calculator 135 calculates the exciting current command IdCB before the magnetic field weakening corresponding to the motor rotation speed ωm. 5 is a diagram showing the relationship between the motor rotation speed ωm of the field current command calculator 135 and the field current command IdC in FIG. 1. The field current command calculator 135 calculates a field current command IdC corresponding to the motor rotation speed ωm.

4 and 5 show the excitation current command characteristics with respect to the motor rotation speed ωm. FIG. 4 shows the excitation current command IdCB before the magnetic field is weakened, and FIG. 5 shows the excitation current command IdC.

As shown in FIG. 4, the excitation current command IdCB before the magnetic field weakens is the sustain current I0 without changing at the motor rotation speed ωm from 0 to ω0. If the motor rotation speed exceeds ω0, the excitation current command IdCB rises from the current I0 with a certain slope in response to an increase in the motor rotation speed ωm.

In addition, as shown in FIG. 5, the excitation current command IdC is a maintenance current I0 that does not change at a motor rotation speed ωm from 0 to ω0. When the motor rotation speed exceeds ω0, it decreases in inverse proportion to the increase in the motor rotation speed ωm.

The field current command calculator 135 is obtained by the following formula The excitation current command before the magnetic field weakens is IdCB.

IdCB = I0

(When 0 ≦ | ωm | ≦ ω0)

IdCB = φ0 + K0. (| ωm | -ω0)

(when ω0 <| ωm |) ... (1)

Here, ω0: basal velocity

I0: Excitation current of substrate velocity

φ0: magnetic flux of base velocity

K0: Coefficient for increasing the magnetizing current command during high-speed rotation

If the motor rotation speed ωm is substituted into the above formula (1) to visualize the exciting current command IdCB before the magnetic field is weakened, it will become a graph as shown in FIG. 4.

By increasing the coefficient K0 of the exciting current during high-speed rotation, the exciting current command during the high-speed rotation of the motor 180 is increased. Even with magnetic saturation, the magnetic flux can not be reduced, and the acceleration and deceleration characteristics can be improved. The optimal value of K0 can be obtained through experiments of trial and error method, or through simulation.

After the field current command calculator 135 obtains the field current command IdCB before the magnetic field is weakened as described above, the field current command IdC is obtained by the following formula.

IdC = IdCB

(When 0 ≦ | ωm | ≦ ω0)

IdC = IdCB. ω0 / | ωm |

(when ω0 <| ωm |) ... (2)

If the motor rotation speed ωm is substituted into the above formula (2), The visualization of the flow command IdC becomes a graph as shown in FIG. 5.

According to the motor rotation speed ωm, the exciting current command calculator 135 calculates the exciting current command IdCB before the magnetic field weakening by performing the calculation of the formula (1), and then formulates the exciting current command IdCB before the magnetic field weakening (2) In the calculation, the excitation current command IdC is output to the d-axis current controller 145.

[Operation of slip frequency calculator 150]

The slip frequency calculator 150 calculates the slip frequency command ωs from the q-axis current command IqC and the d-axis current command IdC after passing through the limiter 190, as shown in the following formula. The slip frequency command ωs is obtained by the following formula.

ωs = R2 / L2. (IqC / IdC) ... (3)

R2: secondary resistance

L2: secondary inductance

[Operation of Motor Control Device 100]

First, the input torque current command IqCB is limited by the limiter 190. The q-axis current IqC output by the limiter 190 is compared with the q-axis current feedback IqF from the coordinate converter 125. The q-axis current controller 130 Find the q-axis voltage command VqC.

On the other hand, the d-axis current command IdC obtained from the motor rotation speed ωm and the d-axis current from the coordinate converter 125 are used by the exciting current command calculator 135 using the above formulas (1) and (2). The feedback IdF is compared, and the d-axis voltage command VdC is obtained by the d-axis current controller 145.

The slip frequency calculator 150 calculates the slip frequency command ωs from the q-axis current command IqC and the exciting current command IdC using the above formula (3). turn The difference frequency command ωs is added to the motor rotation speed ωm output from the speed calculator 115. A primary frequency command ω1 is obtained from the slip frequency command ωs and the motor rotation speed ωm. The integrator 155 integrates the primary frequency command ω1 to obtain the stator position command θmc.

The coordinate converter 160 performs coordinate conversion on the q-axis voltage command VqC and the d-axis voltage command VdC based on the stator position command θmc to obtain three-phase voltage commands Vuc, Vvc, and Vwc. The three-phase voltage commands Vuc, Vvc, and Vwc are supplied to the motor 180 through the PWM controller 165 and the power converter 170, and the motor 180 is driven in response to the three-phase voltage commands Vuc, Vvc, and Vwc.

The q-axis current feedback IqF and the d-axis current feedback IdF are obtained by coordinate conversion of the motor currents Iu and Iv based on the stator position command θmc.

As described above, the field current command calculator 135 finds a value that increases the field current in proportion to the difference between the motor rotation speed and the base speed, and performs magnetic field weakening based on this value. Furthermore, in the field weakening field, it is equal to q The shaft current command Iqc reduces the magnetic flux in proportion. That is, the exciting current command calculator 135 outputs an optimal exciting current command IdC for improving the acceleration / deceleration characteristics of the motor 180.

Therefore, according to the motor control device 100 related to the first embodiment, the torque reduction at the time of high-speed load rotation during power operation of the magnetically saturated motor is improved to shorten the acceleration time, and at the same time, the excessive torque at the time of motor regeneration is suppressed, and It can prevent the over-voltage of the inverter and the over-current of the converter, and there is no rapid change of the torque constant. It can take into account both good acceleration characteristics and safe deceleration characteristics.

Incidentally, the motor control device 100 related to the first embodiment can also be provided with a non-drying controller in a system that outputs the q-axis voltage command VqC and the d-axis voltage command VdC to control the d-axis and the q-axis. In addition, the inside of the d-axis and q-axis current control systems can also be constituted by a three-phase current control system. Furthermore, the excitation current command may not be raised from the base speed, but may be raised from an arbitrary rotation speed.

[Embodiment 2]

[Overall Structure of Motor Control Device 200]

FIG. 6 is a block diagram of a motor control device 200 according to the second embodiment. The motor control device 200 according to the second embodiment is configured by adding a magnetic flux controller and a magnetic flux calculator to the configuration of the motor control device 100 according to the first embodiment. Instead of the field current command calculator 135, a magnetic flux command calculator is provided.

The motor control device 200 includes a q-axis current controller 230, a power operation / regeneration discriminator 275, a q-axis current limit value calculator 285, and a limiter 290 as a system that issues a q-axis voltage command VqC. The q-axis current controller 230, the power operation / regeneration discriminator 275, the q-axis current limit value calculator 285, and the limiter 290 are the q-axis current controller 130, the power operation / regeneration discriminator 175, and the q-axis of the first embodiment. The current limit value calculator 185 and the limiter 190 are the same.

The motor control device 200 includes a magnetic flux command calculator 220, a magnetic flux controller 240, and a d-axis current controller 245 as a system for issuing a d-axis voltage command VdC.

The magnetic flux command calculator 220 outputs the motor rotation speed ωm. The optimal magnetic flux command φ2C for improving the acceleration and deceleration characteristics of the motor 280 is calculated. Incidentally, the detailed operation of the magnetic flux instruction calculator 220 will be described later.

The magnetic flux controller 240 calculates the d-axis current command IdC by inputting a magnetic flux deviation obtained by subtracting the magnetic flux φ2 from the magnetic flux command φ2C output from the magnetic flux command calculator 220. The magnetic flux φ2 is output from the magnetic flux calculator 235. The magnetic flux controller 240 is configured as a proportional-integral controller.

The magnetic flux calculator 235 calculates the magnetic flux φ2 by using the d-axis current output from the coordinate converter 225 to feed back IdF. The detailed operation of the magnetic flux calculator 235 will be described later.

The d-axis current controller 245 calculates the d-axis voltage command VdC by inputting a current deviation obtained by subtracting the d-axis current feedback IdF from the d-axis current command Idc output from the magnetic flux controller 240. The d-axis current feedback IdF is output by the coordinate converter 225. The d-axis current feedback IdF is obtained by performing coordinate conversion on the motor currents Iu and Iv based on a stator position command θmc described later. The d-axis current controller 245 is configured as a proportional-integral controller.

The motor control device 200 includes a slip frequency calculator 250, an integrator 255, an OSC257, and coordinate converters 225 and 260 as a system for performing coordinate conversion.

The slip frequency calculator 250 inputs the input q-axis current command IqC and the magnetic flux φ2 output from the magnetic flux calculator 235 to calculate the slip frequency command ωs. Incidentally, the detailed operation of the slip frequency calculator 250 will be described later.

Integrator 255, OSC257, coordinate converters 225, 260 Yes It is the same as the integrator 155, OSC157, and coordinate converters 125 and 160 of the first embodiment.

The motor control device 200 includes a PWM controller 265 and a power converter 270 as a system for driving the motor 280. The PWM controller 265 and the power converter 270 are the same as the PWM controller 165 and the power converter 170 of the first embodiment. Incidentally, the motor driving unit is formed by the PWM controller 265, the power converter 270, the q-axis current controller 230, the d-axis current controller 245, and the coordinate converter 260.

[Operation of the magnetic flux instruction calculator 220]

As described above, the magnetic flux command calculator 220 calculates an optimal magnetic flux command φ2C for improving the acceleration / deceleration characteristics of the motor 280.

FIG. 7 is a diagram showing the relationship between the motor rotation speed ωm of the magnetic flux command calculator 220 of FIG. 6 and the magnetic flux command φ2CB before the magnetic field is weakened. The magnetic flux command calculator 220 calculates a magnetic flux command φ2CB before the magnetic field weakening corresponding to the motor rotation speed ωm. 8 is a diagram showing the relationship between the motor rotation speed ωm and the magnetic flux command φ2C of the magnetic flux command calculator 220 of FIG. 6. The magnetic flux command calculator 220 calculates a magnetic flux command φ2C corresponding to the motor rotation speed ωm.

7 and 8 show the magnetic flux command characteristics of the magnetic flux φ0 with respect to the motor rotation speed ωm. FIG. 7 shows the magnetic flux command φ2CB before the magnetic field is weakened, and FIG. 8 shows the magnetic flux command φ2C.

As shown in FIG. 7, the magnetic flux command φ2CB before the magnetic field is weakened maintains the magnetic flux φ0 at the motor rotation speed ωm from 0 to ω0. If the motor rotation speed exceeds ω0, the magnetic flux command φ2CB The fixed slope rises.

In addition, as shown in FIG. 8, the magnetic flux command φ2C maintains the magnetic flux φ0 without changing the motor rotation speed ωm from 0 to ω0. If the motor rotation speed exceeds ω0, the magnetic flux command φ2C decreases from the magnetic flux φ0 to an increase in inverse proportion to the motor rotation speed ωm.

The magnetic flux command calculator 220 obtains the magnetic flux command φ2CB before the magnetic field is weakened by the following formula.

φ2CB = φ0

(When 0 ≦ | ωm | ≦ ω0)

φ2CB = φ0 + K0. (| ωm | -ω0)

(when ω0 <| ωm |) ... (4)

Here, ω0: basal velocity

φ0: magnetic flux of base velocity

K0: Coefficient for increasing magnetic flux during high-speed rotation

If the motor rotation speed ωm is substituted into the above formula (4) and the magnetic flux command φ2CB is visualized, it becomes a graph as shown in FIG. 7.

The value of the magnetic flux command φ2CB at high speed and light load rotation can be increased by the coefficient K0 that increases the magnetic flux at high speed. It does not become smaller, which can improve the acceleration and deceleration characteristics. The optimal value of K0 can be obtained through experiments of trial and error method, or through simulation.

The magnetic flux command calculator 220 obtains the magnetic flux command before the magnetic field is weakened as described above, and then obtains the magnetic flux command by the following formula. φ2C.

φ2C = φ2CB

(When 0 ≦ | ωm | ≦ ω0)

φ2C = φ2CB. ω0 / | ωm |

(when ω0 <| ωm |) ... (5)

If the motor rotation speed ωm is substituted into the above formula (5) and the magnetic flux command φ2C is visualized, it becomes a graph as shown in FIG. 8.

The magnetic flux command calculator 220 calculates the magnetic flux command φ2CB before the magnetic field weakening by performing the calculation of the formula (4) in accordance with the rotation speed ωm of the motor, and then performs the calculation of the magnetic flux command φ2CB in the formula (5) to calculate the magnetic flux command φ2C. It is output to the magnetic flux controller 240.

[Operation of slip frequency calculator 250]

The slip frequency calculator 250 calculates the slip frequency command ωs from the q-axis current command Iqc and the magnetic flux φ2 as shown in the following formula. The slip frequency command ωs is obtained by the following formula.

ωs = M. R2 / L2. (Iqc / φ2) ... (6)

R2: secondary resistance

φ2: secondary magnetic flux

L2: secondary inductance

M: Mutual inductance

[Operation of the magnetic flux calculator 235]

The magnetic flux calculator 235 obtains the magnetic flux φ2 from the d-axis current feedback IdF as shown in the following formula.

φ2 = 1 / (1 + L2 / R2.S). M. IdF ... (7)

S: slip

IdF: q-axis current feedback

[Operation of the motor control device 200]

First, the input torque current command IqCB is limited by the limiter 290, and the q-axis current IqC output by the limiter 290 is compared with the q-axis current feedback IqF from the coordinate converter 225. The q-axis current controller 230 Find the q-axis voltage command VqC.

On the other hand, the magnetic flux command calculator 220 that issues the magnetic flux command φ2C uses the above formula (4) and formula (5) to calculate the magnetic flux from the motor rotation speed ωm, and the magnetic flux calculator 235 uses the above formula ( 7) The calculated magnetic flux φ2 is compared, and the d-axis current command IdC is obtained by the magnetic flux controller 240. The d-axis current command IdC is compared with the d-axis current feedback IdF from the coordinate converter 225, and the d-axis voltage command VdC is obtained by the d-axis current controller 245.

The slip frequency calculator 250 calculates the slip frequency command ωs from the q-axis current command IqC and the magnetic flux φ2 using the above formula (6). The slip frequency command ωs is added to the motor rotation speed ωm output from the speed calculator 215. A primary frequency command ω1 is obtained from the slip frequency command ωs and the motor rotation speed ωm. The integrator 255 integrates the primary frequency command ω1 to obtain the stator position command θmc.

The coordinate converter 260 performs coordinate conversion on the q-axis voltage command VqC and the d-axis voltage command VdC based on the stator position command θmc to obtain the three-phase voltage commands Vuc, Vvc, and Vwc. The three-phase voltage commands Vuc, Vvc, and Vwc are supplied to the motor through the PWM controller 265 and the power converter 270. 280. The motor 280 is driven in response to the three-phase voltage commands Vuc, Vvc, and Vwc.

The q-axis current feedback IqF and the d-axis current feedback IdF are obtained by coordinate conversion of the motor currents Iu and Iv based on the stator position command θmc by the coordinate converter 225.

As described above, the magnetic flux command calculator 220 finds a value that increases the magnetic flux in proportion to the difference between the rotation speed of the motor and the base speed, and performs magnetic field weakening based on the value. Furthermore, in the field of magnetic field weakening, it is related to the torque current command. Iqc reduces the magnetic flux proportionally. That is, the magnetic flux controller 240 outputs an optimal exciting current command IdC for improving acceleration / deceleration characteristics of the motor 280.

Therefore, according to the motor control device 200 related to the second embodiment, the torque reduction at the time of high-speed load rotation during power operation of the magnetically saturated motor is improved to shorten the acceleration time, and at the same time, the excessive torque at the time of motor regeneration is suppressed, and It can prevent the over-voltage of the inverter and the over-current of the converter, and there is no rapid change of the torque constant. It can take into account both good acceleration characteristics and safe deceleration characteristics.

Incidentally, the motor control device 200 related to Embodiment 2 may also be provided with a non-drying controller in a system that outputs the q-axis voltage command VqC and the d-axis voltage command VdC to control the d-axis and q-axis. In addition, the inside of the d-axis and q-axis current control systems can also be constituted by a three-phase current control system. Furthermore, the excitation current command may not be raised from the base speed, but may be raised from an arbitrary rotation speed.

[Embodiment 3]

[Overall Structure of Motor Control Device 300]

FIG. 9 is a block diagram of a motor control device 300 according to the third embodiment. The motor control device 300 according to the third embodiment is configured by adding a maximum primary current command calculator, a torque limit value calculator, and a q-axis current calculator to the configuration of the motor control device 200 according to the second embodiment.

The motor control device 300 includes a q-axis current controller 330, a power operation / regeneration discriminator 375, a maximum primary current command calculator 383, a torque limit value calculator 385, a limiter 390, and a q-axis current calculator 395 as the q-axis voltage. Command VqC system. The q-axis current controller 330 and the power operation / regeneration discriminator 375 are the same as the q-axis current controller 230 and the power operation / regeneration discriminator 275 of the second embodiment.

The maximum primary current command calculator 383 calculates the maximum value of the primary current command supplied to the motor 380, and outputs the maximum primary current command IPC to the torque limit value calculator 385. The detailed operation of the maximum primary current command calculator 383 will be described later.

The torque limit value calculator 385 calculates the torque limit value TLIM by the magnetic flux φ2 output from the magnetic flux calculator 335, the d-axis current command IdC outputted by the magnetic flux controller 340, and the maximum primary current command IPC. The detailed operation of the torque limit value calculator 385 will be described later.

The limiter 390 inputs the torque limit value TLIM output from the torque limit value calculator 385 and limits the value of the torque command TCB. The detailed operation of the limiter 390 will be described later.

The q-axis current calculator 395 calculates the q-axis current IqC using the torque command TCB input through the limiter 390. The detailed operation of the q-axis current calculator 395 will be described later.

In addition, the motor control device 300 includes a magnetic flux command calculator 320, a magnetic flux controller 340, and a d-axis current controller 345 as a system for issuing a d-axis voltage command VdC. The magnetic flux command calculator 320, the magnetic flux controller 340, and the d-axis current controller 345 are the same as the magnetic flux command calculator 220, the magnetic flux controller 240, and the d-axis current controller 245 of the second embodiment.

The motor control device 300 includes a slip frequency calculator 350, an integrator 355, an OSC357, and coordinate converters 325 and 360 as a system for performing coordinate conversion. The slip frequency calculator 350, integrator 355, OSC357, and coordinate converters 325 and 360 are the same as the slip frequency calculator 250, integrator 255, OSC257, and coordinate converters 225 and 260 in the second embodiment.

The motor control device 300 includes a PWM controller 365 and a power converter 370 as a system for driving the motor 380. The PWM controller 365 and the power converter 370 are the same as the PWM controller 265 and the power converter 270 of the second embodiment. Incidentally, the motor driving unit is formed by the PWM controller 365, the power converter 370, the q-axis current controller 330, the d-axis current controller 345, and the coordinate converter 360.

[Operation of Power Run / Regeneration Discriminator 375]

As described above, the power operation / regeneration discriminator 375 uses the torque command TCB and the motor rotation speed ωm to determine whether the motor 380 is in the power operation state or the regeneration state.

The determination of power running and regeneration is made by considering the speed ripple caused by the loss of the motor 380 and the quantization error of the encoder 310 as shown in FIG. 10 using the motor rotation speed threshold ωA and the torque command threshold TCA. horse The rotation speed threshold ωA is determined in consideration of the quantization error of the encoder 310, so that the power running and regeneration determination results do not tremble when the motor 380 is running without load. The torque command threshold value TCA is determined in consideration of the loss of the motor 380, and is set to the value of the torque current command TCB when the regenerative power of the motor 380-motor loss = 0.

The power running / regeneration discriminator 375 is determined to be in a regeneration state under the conditions of ωm ≧ ωA and TCB ≦ -TCA, or ωm ≦ -ωA and TCB ≧ TCA as shown in FIG. 10. The condition is judged in the power running state.

[Operation of the maximum primary current command calculator 383]

As described above, the maximum primary current command calculator 383 calculates the maximum primary current command IPC from the power operation and regeneration determination result of the power operation / regeneration discriminator 375 and the motor rotation speed ωm. Specifically, the maximum primary current command calculator 383 does not limit the maximum primary current command IPC in the case of the power running state, and limits the maximum primary current command IPC in the case of the regeneration state as shown in FIG. 11.

Maximum primary current command IPC = IPCmax

(When 0 ≦ | ωm | ≦ ω1)

Maximum primary current command IPC = IPCmax-KLIM. (| ωm | -ω1)

(when ω1 <| ωm |)

Here, ω1: the limit of the q-axis current starts the rotation speed

ω1 is a value higher than the base speed, and is adjusted based on the torque characteristics when the motor 180 is decelerated.

KLIM: Determine the maximum current command value during high-speed rotation Reduction factor

[Action of Limiter 390]

As described above, the limiter 390 inputs the torque limit value TLIM calculated by the torque limit value calculator 385 to limit the value of the torque command TCB.

[Operation of the magnetic flux instruction calculator 320]

As described above, the magnetic flux command calculator 320 calculates an optimal magnetic flux command φ2C for improving the acceleration and deceleration characteristics of the motor 380.

The magnetic flux command calculator 320 obtains the magnetic flux command φ2CB before the magnetic field is weakened by the following formula.

φ2CB = φ0

(When 0 ≦ | ωm | ≦ ω0)

φ2CB = φ0 + K0. (| ωm | -ω0)

(when ω0 <| ωm |) ... (9)

Here, ω0: basal velocity

φ0: magnetic flux of base velocity

K0: Coefficient for increasing magnetic flux during high-speed rotation

When the motor rotation speed ωm is substituted into the above formula (9) and the magnetic flux command φ2CB is visualized, it becomes a graph shown in FIG. 8 as shown in the second embodiment.

The magnetic flux command φ2CB at high speed and light load rotation can be increased by the coefficient K0 that increases the magnetic flux at high speed. It does not become smaller, which can improve the acceleration and deceleration characteristics. About the best of K0 The value can be obtained through trial and error experiments, or through simulation.

The magnetic flux command calculator 320 obtains the magnetic flux command before the magnetic field is weakened as described above, and then obtains the magnetic flux command φ2C by the following formula.

φ2C = φ2CB

(When 0 ≦ | ωm | ≦ ω0)

φ2C = φ2CB. ω0 / | ωm |

(when ω0 <| ωm |) ... (10)

When the motor rotation speed ωm is substituted into the above formula (10) and the magnetic flux command φ2C is visualized, it becomes a graph shown in FIG. 9 as shown in the second embodiment.

The magnetic flux command calculator 320 calculates the magnetic flux command φ2CB before the magnetic field weakening by performing the calculation of the formula (9) in accordance with the rotation speed ωm of the motor, and then performs the calculation of the magnetic flux command φ2CB in the formula (10) to calculate the magnetic flux command φ2C It is output to the magnetic flux controller 340.

[Operation of slip frequency calculator 350]

The slip frequency calculator 350 calculates the slip frequency command ωs from the torque current command Iqc and the magnetic flux φ2C using the above-mentioned formula (6) in the same manner as the slip frequency calculator 250 of the second embodiment.

[The operation of the magnetic flux calculator 335]

The magnetic flux calculator 335 is the same as the magnetic flux calculator 235 of the second embodiment, and uses the above formula (7) to obtain the magnetic flux φ2 from the d-axis current feedback IdF.

[Operation of the torque limit value calculator 385]

The torque limit value calculator 385 calculates the torque limit value TLIM from the d-axis current command IdC and the maximum primary current command IPC using the following formula.

TLIM = Pm. M / L2. φ2. (IPC2-IdC2) 1/2 ... (11)

Here, Pm is the number of pole pairs of the motor 380

[Operation of q-axis current calculator 395]

The q-axis current calculator 395 uses the following formula to obtain a q-axis current command IqC from a torque command that is subjected to torque limitation through the limiter 390.

IqC = L2 / (Pm.M.φ2). (Torque command after torque limitation) ... (12)

[Operation of the motor control device 300]

The input torque command TCB is limited by the limiter 390 to the torque limit value TLIM, and is output to the q-axis current calculator 395. The q-axis current calculator 395 obtains the q-axis current command IqC based on the torque command TCB and the magnetic flux φ2 after the torque limitation. The q-axis current command IqC is compared with the q-axis current feedback IqF from the coordinate converter 325, and the q-axis voltage command VqC is obtained by the q-axis current controller 330. Incidentally, the torque limit value TLIM for limiting the value of the torque command TCB by the limiter 390 is calculated by the torque limit value calculator 385 using the above-mentioned formula (11).

On the other hand, the magnetic flux command calculator 320 that uses the magnetic flux command φ2C to use the magnetic flux calculated by the above equations (9) and (10), and the magnetic flux calculator 335 uses the magnetic flux calculated by the above equation (7) For φ2 comparison, the d-axis current command IdC is obtained by the magnetic flux controller 340. Feedback of d-axis current command IdC and d-axis current from coordinate converter 325 In comparison with IdF, the d-axis voltage command VdC is obtained by the d-axis current controller 345.

The slip frequency calculator 350 calculates the slip frequency command ωs from the torque current command IqC and the magnetic flux φ2 using the above formula (6). The slip frequency command ωs is added to the motor rotation speed ωm output from the speed calculator 315. A primary frequency command ω1 is obtained from the slip frequency command ωs and the motor rotation speed ωm. The integrator 355 integrates the primary frequency command ω1 to obtain the stator position command θmc.

The coordinate converter 360 performs coordinate conversion on the q-axis voltage command VqC and the d-axis voltage command VdC based on the stator position command θmc to obtain the three-phase voltage commands Vuc, Vvc, and Vwc. The three-phase voltage commands Vuc, Vvc, and Vwc are supplied to the motor 380 through the PWM controller 365 and the power converter 370. The motor 380 is driven in response to the three-phase voltage commands Vuc, Vvc, and Vwc.

The q-axis current feedback IqF and the d-axis current feedback IdF are obtained by coordinate conversion of the motor currents Iu and Iv based on the stator position command θmc.

As described above, the magnetic flux command calculator 320 calculates a value that increases the magnetic flux in proportion to the difference between the rotation speed of the motor and the base speed, performs magnetic field weakening based on this value, and furthermore, in the field of magnetic field weakening, it is related to torque current command Iqc reduces the magnetic flux proportionally. That is, the magnetic flux controller 340 outputs an optimal exciting current command IdC for improving acceleration / deceleration characteristics of the motor 380.

Therefore, according to the motor control device 300 related to the third embodiment, the torque reduction at the time of high-speed load rotation during power operation of a magnetically saturated motor is improved to shorten the acceleration time, and at the same time, the motor regeneration is suppressed. Excessive torque prevents over-voltage of the inverter and over-current of the converter, and there is no rapid change in torque constant, which can take into account good acceleration characteristics and safe deceleration characteristics.

Incidentally, the motor control device 300 related to Embodiment 3 may also be provided with a non-drying controller in a system that outputs the q-axis voltage command VqC and the d-axis voltage command VdC to control the d-axis and the q-axis. In addition, the inside of the d-axis and q-axis current control systems can also be constituted by a three-phase current control system. Furthermore, the excitation current command may not be raised from the base speed, but may be raised from an arbitrary rotation speed.

The motor control device related to the present invention increases the magnetic flux in proportion to the rotation speed above the base rotation speed of the motor, and sets the power operation / regeneration discrimination to limit the maximum primary current during regeneration. Thereby, the following motor control device can be realized: the torque at the time of high-speed load at the time of the power running operation of the motor with magnetic saturation is improved to improve the acceleration time. At the same time, it suppresses excessive torque during the regeneration of the motor, prevents overvoltage of the inverter and overcurrent of the inverter, and there is no rapid change in torque constant, which can take into account fast acceleration characteristics and safe deceleration characteristics.

100‧‧‧ Motor control device

110‧‧‧ Encoder

115‧‧‧speed calculator

125‧‧‧ coordinate converter

130‧‧‧q axis current controller

135‧‧‧Excitation current command calculator

145‧‧‧d-axis current controller

150‧‧‧Slip Frequency Calculator

155‧‧‧Integrator

157‧‧‧OSC

160‧‧‧coordinate converter

165‧‧‧PWM controller

170‧‧‧ Power Converter

175‧‧‧Power running / regeneration discriminator

180‧‧‧ Motor

185‧‧‧q-axis current limit calculator

190‧‧‧Limiter

Claims (10)

A motor control device, comprising: a power running / regeneration discriminator, which uses a torque current command and a motor rotation speed to determine the power running / regeneration state of the motor; and a limiter, which causes the torque current to be generated when the motor is in the power running state The command is passed. In the regeneration state, the size of the aforementioned torque current command is limited and passed. The field current command calculator uses the aforementioned motor rotation speed to recognize the rotation state of the motor, and calculates the field current command corresponding to the rotation state. The drive unit drives the motor using the torque current command and the calculated exciting current command after passing through the limiter; and a q-axis current limit value calculator that uses the power of the motor to operate / regenerate. The state and the motor rotation speed are used to calculate the limit value of the limiter when the motor is in a regeneration state. The limiter uses the limit value calculated by the q-axis current limit value calculator to limit the size of the torque current command. For example, the motor control device according to claim 1, wherein when the above-mentioned motor rotation speed is higher than the base speed, the field current command before the magnetic field weakening is obtained, and then the field current command before the magnetic field weakening is obtained. In calculating the field current command, the field current command before the magnetic field weakens is proportional to the difference between the motor rotation speed and the base speed, and the field current command is proportional to the motor rotation speed. The difference between degree and basal velocity is inversely proportional. For example, the motor control device of claim 1 or 2 further includes a coordinate converter, and the coordinate converter obtains a q-axis current feedback and a d-axis current feedback by performing coordinate conversion on a current supplied to the aforementioned motor; the aforementioned motor driving unit A voltage command for driving the motor is obtained by using a value obtained by subtracting the q-axis current feedback from the torque current command and a value obtained by subtracting the d-axis current feedback from the exciting current command. For example, the motor control device of claim 3 further includes a slip frequency calculator which calculates the rotation based on the torque current command passed through the aforementioned limiter and the field current command calculated by the field current command calculator. Difference frequency command; the coordinate converter uses the slip frequency command calculated by the slip frequency calculator to perform coordinate conversion on the current supplied to the motor. The motor control device according to claim 1 or 2, wherein the power running / regeneration discriminator is in a case where the motor rotation speed is greater than a set motor rotation speed threshold and the magnitude of the torque current command is smaller than the set torque current threshold Or, if the motor rotation speed is smaller than the set motor rotation speed threshold and the torque current command is larger than the set torque current threshold, it is determined that the motor is in a regenerative state, and in other cases than the above, It is determined that the motor is in a power running state. For example, the motor control device of claim 1, wherein the q-axis current limit value calculator calculates the limit value of the motor in the regeneration state by the following formula: Limit value IqLIM = Iqmax (when 0 ≦ | ωm | ≦ ω1) limit value IqLIM = Iqmax-KLIM. (| ωm | -ω1) (when ω1 <| ωm |) Here, ω1: The limit of the q-axis current starts the rotation speed, ω1 is a value above the base speed, and is adjusted based on the torque characteristics when the motor is decelerating, KLIM: Coefficient that determines the reduction amount of the q-axis current command limit value during high-speed rotation. A motor control device, comprising: a power running / regeneration discriminator, which uses a torque current command and a motor rotation speed to determine the power running / regeneration state of the motor; and a limiter, which causes the torque current to be generated when the motor is in the power running state When the command is passed, the size of the torque current command is limited to pass it in the regeneration state; the magnetic flux command calculator calculates the magnetic flux command of the motor using the motor rotation speed; the magnetic flux controller uses the current supplied to the motor The obtained magnetic flux and the magnetic flux command calculated by the magnetic flux command calculator to obtain an exciting current command; the motor driving unit drives the motor using the torque current command and the obtained exciting current command after passing the limiter; And q-axis current limit value calculator, the q-axis current limit value calculator uses the power running / regenerating state of the motor and the motor rotation speed The limit value of the limiter when the motor is in a regenerative state is calculated. The limiter uses the limit value calculated by the q-axis current limit value calculator to limit the magnitude of the torque current command. For example, the motor control device of claim 7, wherein the magnetic flux command calculator calculates the magnetic flux command before the magnetic field weakens when the motor rotates at a higher speed than the base speed, and then calculates the magnetic flux command from the magnetic flux command before the obtained magnetic field weakens. The magnetic flux command before the magnetic field weakening is proportional to the difference between the motor rotation speed and the base speed, and the magnetic flux command is inversely proportional to the difference between the motor rotation speed and the base speed. The motor control device according to claim 7 or 8, wherein the magnetic flux obtained from the current supplied to the motor is obtained from a d-axis current feedback obtained by the magnetic flux calculator from the coordinate conversion of the current supplied to the motor. A motor control device, comprising: a power running / regeneration discriminator that uses a torque command and a motor rotation speed to determine the power running / regeneration state of the motor; and a limiter that passes the torque command when the motor is in the power running state In the regeneration state, the size of the aforementioned torque command is limited and passed; the q-axis current calculator uses the torque command that has passed the aforementioned limiter to calculate the torque current command; the magnetic flux command calculator uses the aforementioned motor rotation speed to calculate Magnetic flux instruction of the aforementioned motor; The magnetic flux controller uses the magnetic flux calculated from the current supplied to the motor and the magnetic flux command calculated by the magnetic flux command calculator to obtain the exciting current command; the motor drive unit uses the calculated torque current command and obtains The current is driven by the excitation current command; the maximum current command calculator uses the power running / regeneration state of the motor and the motor rotation speed to calculate the maximum current command when the motor is in the regeneration state; and a torque limit value calculator Using the maximum current command calculated by the maximum current command calculator, the excitation current command obtained by the magnetic flux controller, and the magnetic flux calculated by the magnetic flux calculator to calculate the limits of the limiter when the motor is in a regenerative state. The limiter is a limit value calculated by the torque limit value calculator to limit the size of the torque command.