JP2010246260A - Motor control device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor control device and method for improving torque estimation precision by output of a voltage as a voltage command value in controlling pulse modulation. <P>SOLUTION: The motor controller is controlled by pulse modulation control and includes an inverter controlling a motor. The motor controller includes a dq/pole coordinate conversion unit for calculating an amplitude command value and a first voltage phase angle command value based on a d-axis/q-axis voltage command value and a mover position of the motor, a voltage phase compensating unit for adding a lead phase compensation value calculated based on a control period and a motor electric angle one period to the first voltage phase angle command value and generating a second voltage phase angle command value, and a first pole coordinate/UVW converting unit for generating a first voltage command value performing pulse modulation control based on the amplitude command value, the second voltage phase angle command value and the mover position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a technique for controlling a permanent magnet synchronous motor.

  Conventionally, as a method of controlling a permanent magnet synchronous motor, torque control is performed by causing the output torque to follow a desired value. In torque control, the output torque value is fed back and control is performed, so it is necessary to estimate the output torque. As the output torque estimation method, for example, there are a method using the estimated output torque value in the UVW phase (Equation 1) and a method using the torque estimation equation on the dq axis (Equation 2).

Tdet = (Vu ^* × Iu + Vv ^* × Iv + Vw ^* × Iw) / ω (Formula 1)
Vu ^* , Vv ^* , Vw ^* : UVW phase voltage command value [V]
Iu, Iv, Iw: current value of UVW phase [A]
ω: Angular velocity measurement value [rad / sec]

Tdet = (Vd ^* × Id + Vq ^* × Iq) / ω (Formula 2)
Vd ^* , Vq ^* : d-axis / q-axis voltage command value [V]
Id, Iq: d axis / q axis current value [A]
ω: Angular velocity measurement value [rad / sec]

However, in the output torque estimation of Equation 1, Vu ^* , Vv ^* , Vw ^* are used as voltage command values in the equation, and in the output torque estimation of Equation 2, the d-axis / q-axis voltage command is included in the equation. Since the values Vd ^* and Vq ^* are used, there is a problem that a voltage according to the voltage command value is not output.

  In addition, during PWM control, the command value can be changed only every control cycle, so that a large torque estimation error occurs as the output voltage phase is delayed by 1/2 control cycle from the command value, in particular, as the output frequency increases. Further, when a torque estimation error occurs, there is a problem that the output torque cannot be controlled to a desired value.

  According to Patent Document 1, since the internal impedance is large, the AC input voltage command of the PWM converter becomes a sine wave, and the average value obtained by correcting the calculation cycle of the AC input voltage command is integrated. And the AC input terminal is PWM-controlled by this voltage command average value.

  According to Patent Document 2, an internal resistance of a complementary drive element of a drive circuit is changed in an analog or digital manner by a step signal divided by an electrical angle from a waveform setting combination circuit of a control unit, and a phase current is changed. Drives a delta-connected three-phase motor that approximates a sine waveform. In addition, when the internal resistance of the complementary drive element becomes infinite, the phase of the motor can be detected by the phase detection circuit, and it is fed back to the control of the delta-connected three-phase motor. There have been proposals for improving control and driving by giving a step signal obtained by dividing an electrical angle by a combination of settings.

JP 2001-286147 A JP-A-9-84384

  Motor control that improves the torque estimation accuracy by outputting the voltage according to the command value during pulse modulation control (such as PWM control or PAM (Pulse Amplitude Modulation) control). An object is to provide an apparatus and a motor control method.

  A motor control device that is controlled by pulse modulation control, which is one of the modes, and includes an inverter that controls the motor includes a dq / polar coordinate conversion unit, a voltage phase compensation unit, and a first polar coordinate / UVW conversion unit.

  The dq / polar coordinate converter calculates an amplitude command value and a first voltage phase angle command value based on the d-axis / q-axis voltage command value and the position of the moving element of the motor. The voltage phase compensation unit generates a second voltage phase angle command value by adding the advance phase compensation value calculated based on the control cycle and one motor electrical angle cycle to the first voltage phase angle command value. The first polar coordinate / UVW converter generates a first voltage command value for pulse modulation control based on the amplitude command value, the second voltage phase angle command value, and the moving element position.

With the above configuration, it is possible to improve torque estimation accuracy by outputting a voltage according to the voltage command value during pulse modulation control.
The voltage phase compensation unit calculates a lead phase compensation value by adding π obtained by dividing the control cycle by one cycle of the motor electrical angle and calculates the lead phase compensation value to the first voltage phase angle command value. The phase compensation value is added to generate the second voltage phase angle command value.

  The second polar coordinate / UVW converter calculates a second voltage command value based on the amplitude command value, the first voltage phase angle command value, and the mover position. The torque calculation unit includes a UVW-phase output current value of the inverter controlled based on the voltage command value generated by the first polar coordinate / UVW conversion unit, an angular velocity value of the motor, and the second voltage command. A torque estimated value is calculated based on the value. The torque control unit selectively generates a d-axis / q-axis current command value based on a difference between the torque command value and the estimated torque value. The current control unit uses the d-axis / q-axis current command value, the UVW-phase output current value of the inverter, and the d-axis / q-axis current value calculated based on the moving element position to determine the dq / polar coordinate conversion unit. The d-axis / q-axis voltage command value as an input is calculated.

  The motor control device is provided with a rectangular wave control unit that controls the inverter separately from the PWM control or PAM control that is the pulse modulation control, and when the PWM control or PAM control is switched to the rectangular wave control, The first voltage phase angle command value immediately before switching is acquired and set as an initial value.

  Torque estimation accuracy can be improved by outputting a voltage according to the command value during pulse modulation control.

It is a figure which shows the control apparatus of a permanent magnet synchronous motor. It is a block diagram which shows the drive control system of a permanent magnet synchronous motor. It is a figure which shows the operation | movement flow of lead phase compensation. A to D are diagrams showing tables recorded in the recording unit. It is a figure which shows that UVW phase output voltage U, V, W is delayed by 1/2 control period from a voltage command value. It is a block diagram of the apparatus provided with the PWM control part and the rectangular wave control part in the drive control system of the permanent magnet synchronous motor. It is a figure which shows that a voltage phase error generate | occur | produces at the time of control switching. It is a flowchart in the case of reducing a voltage phase error when switching between PWM control and control other than PWM control.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Example 1
FIG. 1 is a diagram showing a control device for a permanent magnet synchronous motor. The permanent magnet synchronous motor control device includes an inverter 2, a control unit 3, a drive unit 4, and a recording unit 5, and controls the permanent magnet synchronous motor 1 (M). In the conventional permanent magnet synchronous motor control device, during PWM (Pulse Width Modulation) control, the voltage command value can be changed only for each control cycle, so the phase of the output voltage of the inverter 2 is relative to the voltage command value. Delayed by 1/2 control cycle. Therefore, by correcting the voltage phase angle command, the torque estimation accuracy is improved by outputting a voltage according to the voltage command value during PWM control.

  The permanent magnet synchronous motor 1 is connected to an AC output terminal of an inverter 2 controlled by the control unit 3 and is driven by an AC current (U phase, V phase, W phase) output from the AC output terminal.

  In addition, it is not limited to the permanent magnet synchronous motor 1, What is necessary is just an AC motor. A synchronous machine including a permanent magnet synchronous motor and a synchronous reluctance motor is desirable, but an induction motor may be used. Moreover, it is not limited to a rotary electric machine, Electric motors, such as a linear motor, may be sufficient.

  The inverter 2 is configured by connecting two switching elements (for example, IGBT (Insulated Gate Bipolar Transistor)) connected in series to each other in parallel to a DC power source via a capacitor. Then, when each switching element of the inverter 2 is turned on / off, an alternating current is output from each connection point (U phase, V phase, W phase) of the switching element. The control unit 3 is hardware that controls the permanent magnet synchronous motor 1. For example, you may comprise using CPU, DSP, and a pluggable device. The drive unit 4 outputs a drive signal for turning on / off each switching element of the inverter 2 by PWM control. The control unit 3 acquires a signal (analog signal) output from a sensor or the like by converting it into a digital signal using an A / D converter, and uses it when executing a process described later.

The recording unit 5 is connected to the control unit 3 and includes a memory such as a ROM and a RAM. A program and data for controlling the permanent magnet synchronous motor 1 described later are recorded.
FIG. 2 is a block diagram showing a drive control system of the permanent magnet synchronous motor 1. The drive control system includes a torque control unit 6, a current control unit 7, a dq / polar coordinate conversion unit 8, a voltage phase compensation unit 9, a first polar coordinate / UVW conversion unit 10, a PWM generation unit 11, a UVW / dq conversion unit 12, A second polar coordinate / UVW converter 13, a torque calculator 14, a position detector 15, a speed calculator 16, and current sensors 17a and 17b are provided.

The torque control unit 6 calculates a torque difference value (= torque command value T ^* −torque estimated value Tdet) that is a difference between a torque command value T ^* and a torque estimated value Tdet described later, and based on the torque difference value. Thus, the d-axis current command value Id ^* and the q-axis current command value Iq ^* are generated. For example, torque / dq conversion is performed using a table in which the torque difference value created in advance recorded in the recording unit 5 is associated with the d-axis current command value Id ^* and the q-axis current command value Iq ^* .

The current control unit 7 includes a d-axis current control unit and a q-axis current control unit. The d-axis current control unit generates a d-axis voltage command value Vd ^* based on the difference between the d-axis current command value Id ^* and the d-axis current value Id output from the UVW / dq conversion unit 12. Similarly, the q-axis current control unit generates a q-axis voltage command value Vq ^* based on the difference between the q-axis current command value Iq ^* and the q-axis current value Iq output from the UVW / dq conversion unit 12.

Based on the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* , the dq / polar coordinate conversion unit 8 determines an amplitude command value M and a voltage phase angle command value φ ^* (first voltage phase angle command value) described later. Is generated.

The voltage phase compensator 9 (leading phase compensation) corrects a voltage phase angle command value φ ^* , which will be described later, using the voltage phase angle command value φ ^* , the control cycle Ts, and the electrical angle cycle T, and the voltage phase angle command value φref is generated.

In the first polar coordinate / UVW conversion unit 10, UVW phase voltage command values Vu ^** , Vv ^** , Vw ^** (described below) based on the amplitude command value M, the voltage phase angle command value φref, and the moving element position θ. 1 voltage command value) is generated.

The PWM generator 11 and the drive unit 4 generate PWM signals Vu, Vv, and Vw for each phase according to the UVW phase voltage command values Vu ^** , Vv ^** , and Vw ^** . The motor current supplied to each phase of the permanent magnet synchronous motor 1 is determined by the duty of the corresponding PWM signal Vu, Vv, Vw.

In this example, the PWM generator 11 is used, but PAM control or the like may be used instead of PWM control.
The UVW / dq conversion unit 12 monitors the output of the position detection unit 15 with respect to the moving element position θ of the permanent magnet synchronous motor 1 and sets the detected value of the motor current supplied to the permanent magnet synchronous motor 1 to the d axis / q axis. Convert to current value. Here, the U-phase current Iu and the W-phase current Iw detected using the current sensors 17a and 17b are converted into a d-axis current value Id and a q-axis current value Iq. The d-axis current is a so-called field current and is a current vector component for generating a field. The q-axis current is a so-called torque current and is a current vector component for generating torque.

The second polar coordinate / UVW conversion unit 13 determines the UVW phase voltage command values Vu ^* , Vv ^* , Vw ^* (second voltage command) based on the amplitude command value M, the voltage phase angle command value φ ^*, and the mover position θ. Value).

The torque calculation unit 14 calculates the V-phase current value Iv using the UW-phase current values Iu and Iw, and the permanent magnet synchronization calculated by the UVW-phase voltage command values Vu ^* , Vv ^* , Vw ^* , and the speed calculation unit 16. The estimated torque value Tdet is calculated by Equation 3 using the angular velocity ω of the motor 1.

Tdet = (Vu ^* × Iu + Vv ^* × Iv + Vw ^* × Iw) × η / ω (Formula 3)
Vu ^* , Vv ^* , Vw ^* : UVW phase voltage command value [V]
Iu, Iv, Iw: current value of UVW phase [A]
ω: Angular velocity measurement value [rad / sec]
η: Efficiency

The position detection unit 15 detects the rotor position θ of the rotor of the permanent magnet synchronous motor 1.

The speed calculation unit 16 calculates the angular speed ω of the permanent magnet synchronous motor 1 based on the mover position θ detected by the position detection unit 15.
(Description of operation)
FIG. 3 shows an operation flow of phase compensation.

In step S1, an amplitude command value M and a voltage phase angle command value φ ^* are generated based on the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* . The control unit 3 acquires the d-axis voltage command value Vd ^* and the q-axis voltage command value Vq ^* calculated by the current control unit 7 recorded in the recording unit 5 and the mover position θ measured by the position detection unit 15. Then, the data is input to the dq / polar coordinate converter 8 (see table A in FIG. 3). Then, the amplitude command value M and the voltage phase angle command value φ ^* are calculated according to Equation 4. “^” Means a power.

M = (3/2) ^ 1/2 × (Vd ^* ^ 2 + Vq ^* ^ 2) ^ 1/2 (Formula 4)
φ ^* = θ + tan ⁻¹ (−Vq ^* / Vd ^* )

The calculated amplitude command value M and voltage phase angle command value φ ^* are recorded in the recording unit 5 (see Table B in FIG. 3).

In step S2, the control unit 3 performs advance phase compensation, so that the amplitude command value M, the voltage phase angle command value φ ^* , the control cycle Ts (machine cycle, etc.) recorded in the recording unit 5, and the motor electrical angle 1 cycle T is acquired and input to the voltage phase compensation unit 9 (see Table B in FIG. 3). The voltage phase compensator 9 calculates a voltage phase angle command value φref that has been voltage phase compensated according to Equation 5.

φref = φ ^* + (1/2) × 2π × (Ts / T) (Formula 5)
φref: Compensated voltage phase angle command [rad]
φ ^* : Voltage phase angle command before compensation [rad]
T: 1 cycle of motor electrical angle [sec]
Ts: Control cycle [sec]

The calculated voltage phase angle command value φref after voltage phase compensation is recorded in the recording unit 5 (see table C in FIG. 3). The lead phase compensation value is (1/2) × 2π × (Ts / T).

In step S3, the control unit 3 acquires the voltage phase angle compensated voltage phase angle command value φref and the amplitude command value M recorded in the recording unit 5 and inputs them to the first polar coordinate / UVW conversion unit 10 (FIG. 3 Tables B and C). The first polar coordinate / UVW conversion unit 10 calculates UVW phase voltage command values Vu ^** , Vv ^** , and Vw ^** according to Equation 6.

Vu ^** = M × sin (φref) (Formula 6)
Vv ^** = M × sin (φref− (2π / 3))
Vw ^** = M × sin (φref + (2π / 3))

The calculated UVW phase voltage command values Vu ^** , Vv ^** , and Vw ^** are recorded in the recording unit 5 by the control unit 3 (see Table D in FIG. 3).

In step S4, PWM signals Vu, Vv, Vw for each phase are generated according to the UVW phase voltage command values Vu ^** , Vv ^** , Vw ^** . The control unit 3 acquires the UVW phase voltage command values Vu ^** , Vv ^** , and Vw ^** recorded in the recording unit 5 and inputs them to the PWM generation unit 11 to generate a PWM signal using existing technology. PWM signals Vu, Vv, and Vw are output via the drive unit 4.

Further, the control unit 3 acquires the voltage phase angle command value φ ^* and the amplitude command value M recorded in the recording unit 5 and inputs them to the second polar coordinate / UVW conversion unit 13. The second polar coordinate / UVW conversion unit 13 calculates UVW phase voltage command values Vu ^* , Vv ^* , Vw ^* according to Equation 7.

Vu ^* = M × sin (φ ^* ) (Formula 7)
Vv ^* = M × sin (φ ^* − (2π / 3))
Vw ^* = M × sin (φ ^* + (2π / 3))

The calculated UVW phase voltage command values Vu ^* , Vv ^* , Vw ^* are recorded in the recording unit 5 by the control unit 3.

Next, the control unit 3 sets the output current values Iu and Iw of the inverter 2 controlled based on the PWM signals Vu, Vv, and Vw recorded in the recording unit 5 and the mover position θ of the permanent magnet synchronous motor 1. Based on the angular velocity measurement value ω calculated based on the UVW phase voltage command values Vu ^* , Vv ^* , and Vw ^* , the estimated torque value Tdet is calculated by the above equation 3.

Next, the torque command value T ^* set and recorded in advance and the calculated estimated torque value Tdet are acquired by the control unit 3, and the d-axis current command value Id ^* and q-axis current command calculated by the torque control unit 6 are acquired. Calculate and record the value Iq ^* .

Thereafter, the d-axis voltage command value Vd ^* is calculated using the d-axis current command value Id ^* , the q-axis current command value Iq ^*, and the d-axis / q-axis current values Id and Iq calculated by the UVW / dq converter 12 ^. And q-axis voltage command value Vq ^* is calculated and recorded in the recording unit 5.

Conventionally, as shown in FIG. 4 (vertical axis: voltage value, horizontal axis: time), the voltage command value can be changed only at every control cycle Ts. The UVW phase output voltages U, V, and W output from 2 are delayed by a 1/2 control cycle from the voltage command value. That is, Vu ^* = Vu, Vv ^* = Vv, and Vw ^* = Vw are not satisfied. Further, since the voltage command value is used for torque calculation instead of the actual output voltage, a large error occurs in the torque calculation.

However, by controlling as described above, the difference between the UVW phase voltage command values Vu ^* , Vv ^* , Vw ^* and the UVW phase output voltages U, V, W shown in FIG. 4 can be minimized. Accurate torque estimation is possible.
(Example 2)
FIG. 5 is a block diagram of an apparatus including a PWM control unit 3 a and a rectangular wave control unit 51 in the drive control system of the permanent magnet synchronous motor 1. The PWM control unit 3a is a drive control system for the permanent magnet synchronous motor 1 described in the first embodiment.

In this example, an apparatus including the PWM control unit 3a and the rectangular wave control unit 51 is shown, but a control unit such as PAM control may be used instead of the PWM control unit 3a.
The rectangular wave control unit 51 acquires the voltage phase angle command value φ ^* generated by the dq / polar coordinate conversion unit 8 of the PWM control unit 3a immediately before the control is switched from the PWM control unit 3a to the rectangular wave control unit 51, The UVW phase output voltages U, V, and W are generated based on the voltage phase angle command value φ ^* . Further, the rectangular wave control unit 51 generates PWM signals Vu, Vv, and Vw based on the moving element position θ and the voltage phase angle command value φ.

The switching unit 52 switches the paths of the UVW phase voltage command values Vu ^* , Vv ^* , Vw ^* output of the PWM control unit 3a and the rectangular wave control unit 51 for the control of the permanent magnet synchronous motor 1. For example, the switching is performed by acquiring a switching control signal generated based on the rotational speed of the permanent magnet synchronous motor 1 or the like. This switching control signal is also notified to the PWM control unit 3a and the rectangular wave control unit 51.

  Conventionally, when switching from PWM control to control other than PWM (rectangular wave control in this example), the voltage phase angle command value immediately before switching is used to match the voltage phase before and after switching. However, if there is a voltage phase delay during PWM control, as shown in FIG. 6 (vertical axis: voltage value, horizontal axis: time), a voltage phase error occurs at the control switching point, and a large torque shock occurs.

Therefore, by using the voltage phase angle command value φ ^* generated by the dq / polar coordinate conversion unit 8 of the PWM control unit 3a in the control other than the PWM control, the voltage phase error before and after the switching is eliminated and the torque fluctuation can be reduced. .
(Description of operation)
FIG. 7 is a flowchart of processing for reducing a voltage phase error when switching between PWM control and control other than PWM control. Note that control methods other than PWM do not cause voltage phase delays.

The processes in steps S1 to S4 are the same as those in the first embodiment.
In step S5, a control method is selected. For example, the switching unit 52, the PWM control unit 3a, and the rectangular wave control unit 51 acquire the switching control signal. When the switching unit 52 detects the switching control signal, the switching unit 52 switches the UVW phase voltage command values Vu ^* , Vv ^* , and Vw ^* output paths. When detecting the switching control signal, the rectangular wave control unit 51 acquires the voltage phase angle command value φ ^* from the PWM control unit 3a.

In step S6, the rectangular wave control unit 51 performs the calculation of the UVW phase output voltages U, V, and W using the voltage phase angle command value φ ^* and the moving element position θ in the first control cycle. In the control cycle, the UVW phase output voltages U, V, and W are calculated using the voltage phase angle command value φ and the mover position θ generated by the rectangular wave control unit 51. That is, when switching from PWM control to control other than PWM control, the first voltage phase angle command value immediately before switching is acquired and set as an initial value.

By using the voltage phase angle command value φ ^* generated by the dq / polar coordinate conversion unit 8 as described above for control other than PWM control, the voltage phase error before and after switching as shown in FIG. 6 is eliminated and torque fluctuation is reduced. can do.

When a voltage phase delay occurs in a control method other than PWM, the same effect can be expected by correcting a control unit other than PWM.
The present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the gist of the present invention.

1 Permanent magnet synchronous motor,
2 inverter,
3 Control unit,
3a PWM controller,
4 Drive unit,
5 Recording section,
6 Torque control unit,
7 Current controller,
8 dq / polar coordinate converter,
9 Voltage phase compensator,
10 1st polar coordinate / UVW conversion part,
11 PWM generator,
12 UVW / dq converter,
13 Second polar coordinate / UVW converter,
14 Torque calculator,
15 position detector,
16 Speed calculator,
17a, 17b current sensor,
51 rectangular wave control unit,
52 switching part,

Claims (5)

A motor control device that is controlled by pulse modulation control and includes an inverter for controlling the motor,
a dq / polar coordinate converter that calculates an amplitude command value and a first voltage phase angle command value based on a d-axis / q-axis voltage command value and a position of the moving element of the motor;
A voltage phase compensator that generates a second voltage phase angle command value by adding a lead phase compensation value calculated based on a control cycle and a motor electrical angle cycle to the first voltage phase angle command value;
A first polar coordinate / UVW converter that generates a first voltage command value for pulse modulation control based on the amplitude command value, the second voltage phase angle command value, and the moving element position;
A motor control device comprising: The voltage phase compensator is
A value obtained by dividing the control period by one period of the motor electrical angle and π are integrated to calculate the lead phase compensation value, and the lead phase compensation value is added to the first voltage phase angle command value to add the lead phase compensation value. The motor control device according to claim 1, wherein a voltage phase angle command value of 2 is generated. A second polar coordinate / UVW converter that calculates a second voltage command value based on the amplitude command value, the first voltage phase angle command value, and the mover position;
Torque based on the UVW phase output current value of the inverter controlled based on the voltage command value generated by the first polar coordinate / UVW converter, the angular velocity value of the motor, and the second voltage command value A torque calculator for calculating an estimated value;
A torque control unit that selectively generates a d-axis / q-axis current command value based on a difference between the torque command value and the estimated torque value;
The d-axis that is an input to the dq / polar coordinate conversion unit based on the d-axis / q-axis current value calculated based on the UVW-phase output current value of the inverter and the moving element position and the d-axis / q-axis current command value A current control unit for calculating a q-axis voltage command value;
The motor control device according to claim 2, further comprising: In addition to PWM control or PAM control that is the pulse modulation control, the motor control device is provided with a rectangular wave control unit that controls the inverter,
The said rectangular wave control part acquires the said 1st voltage phase angle command value just before switching, when it switches from the said PWM control or PAM control to rectangular wave control, It is characterized by the above-mentioned. The motor control device described in 1. A method for controlling a motor that is controlled by pulse modulation control and includes an inverter for controlling the motor,
An amplitude command value and a first voltage phase angle command value are generated based on the d-axis / q-axis voltage command value and the slider position of the motor,
A lead phase compensation value calculated by integrating a value obtained by dividing the control cycle by one motor electrical angle cycle and π is added to the first voltage phase angle command value to generate the second voltage phase angle command value. And
Generating a first voltage command value for PWM control based on the amplitude command value, the second voltage phase angle command value, and the slider position;
The motor control method characterized by the above-mentioned.

Images