JP2005269761A - Magnetic pole position error correcting method and drive apparatus of permanent magnet motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for estimating a difference between a magnetic pole position indicated by an encoder and a true magnetic pole position from a voltage, a current and a rotational angular speed during an operation of a permanent magnet motor, and correcting an error of the magnetic pole position. <P>SOLUTION: The method operates the permanent magnet motor in an arbitrary state, and is provided with a step ST1 for measuring a d-axis current, a q-axis current and a d-axis voltage in forward and backward rotations, a step ST3 for estimating the magnetic pole position error of the permanent magnet motor based on a rotation speed, the voltage and the currents, and a step ST10 for correcting the magnetic pole position detected by the encoder with the magnetic pole position error of the permanent magnet motor and loading a corrected value as true magnetic pole position information into a current controller and a torque controller. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to correction of a magnetic pole position error of a permanent magnet motor.

In general, in order to drive a permanent magnet synchronous motor, it is necessary to grasp the magnetic pole position, which is the direction of the magnetic flux produced by the permanent magnet, and an encoder for that purpose is attached to detect the magnetic pole position. However, there is a slight difference between the magnetic pole position indicated by the encoder and the true magnetic pole position due to errors that occur during processing or assembly. Various methods or apparatuses for detecting the difference and correcting the magnetic pole position indicated by the encoder to obtain the true magnetic pole position have been proposed. For example, in Patent Literature 1, the encoder is instructed by comparing the phase of the induced voltage generated when the permanent magnet motor is driven from the outside and rotated at a predetermined speed with the phase of the magnetic pole position detected by the encoder. A method for obtaining a magnetic pole position and a true magnetic pole position is disclosed.
Japanese Patent Laid-Open No. 11-168895

However, since the method disclosed in Patent Document 1 obtains the phase of the no-load induced voltage, there is a problem that the magnetic pole position cannot be obtained during operation of the electric motor.
Accordingly, an object of the present invention is to provide a method for correcting a magnetic pole position error by estimating the difference between the magnetic pole position indicated by the encoder and the true magnetic pole position from the voltage, current, and rotational angular velocity during operation of the permanent magnet motor. To do.

  In order to solve the above-mentioned problem, the invention of claim 1 is a method for correcting a magnetic pole position error of a permanent magnet motor that corrects a magnetic pole position error of a permanent magnet motor provided with an encoder for detecting a magnetic pole position. And measuring the d-axis current, the q-axis current, and the d-axis voltage by forward rotation and reverse rotation, and based on the rotation speed, the voltage, and the current measurement value, the permanent magnet motor And estimating the magnetic pole position error of the permanent magnet motor and taking the value obtained by correcting the magnetic pole position detected by the encoder with the magnetic pole position error of the permanent magnet motor into the current controller and torque controller as true magnetic pole position information. is there.

The invention of claim 2 uses the following formula for estimating the magnetic pole position error angle.
sinε = {(V _dR −V _dF ) −R (i _dR −i _dF ) + ωL _q (i _qR −i _qF )} / {2 · ω _r · K _E }
Where ε is the error angle (rad) of the magnetic pole position detected by the encoder with respect to the true magnetic pole position, ω _r is the rotational angular velocity (rad / sec) in the operating state, and V _dF and V _dR are forward rotation and The d-axis voltage (V), i _dF , i _dR in the reverse direction rotation are the d-axis current (A) in the forward direction and the reverse direction, respectively, i _qF , i _qR are the shaft currents in the forward direction and the reverse direction, respectively. (A), ω is electrical angular velocity (rad / sec), R is armature winding resistance (Ω), L _q is q-axis inductance (H), K _E is induced voltage coefficient (V / (rad / sec)) And

  According to a third aspect of the present invention, a device for executing the magnetic pole position error correction method for a permanent magnet motor according to the first or second aspect is incorporated with a drive device for the permanent magnet motor.

  According to the present invention, the magnetic pole position error angle of the permanent magnet motor is estimated based on the rotational angular velocity, voltage, and current measured during operation of the permanent magnet motor, and the error is corrected, and torque control and current control are performed. There is an effect of improving accuracy.

  The best mode for carrying out the present invention will be described below.

FIG. 1 is a flowchart of a magnetic pole position error estimation method showing an embodiment of the present invention. Hereinafter, this flow will be described step by step.
(Step ST1) The rotational angular velocity, d-axis voltage, d-axis current, and q-axis current in forward rotation and reverse rotation are measured. The voltage and current may be d-axis, q-axis converted values or command values from three-phase current measured values.
(Step ST2) The armature winding resistance, q-axis inductance, and induced voltage coefficient which are motor parameters are read.
(Step ST3) The magnetic pole position error is estimated by substituting the aforementioned rotational angular velocity, d-axis voltage, d-axis current, q-axis current, armature winding resistance, q-axis inductance, and induced voltage coefficient into the following formula.

sin ε = {(V _dR −V _dF ) −R (i _dR −i _dF ) + ωL _q (i _qR −i _qF )} / {2 · ω _r · K _E } (Formula 1)

Where ε is the error angle (rad) of the magnetic pole position detected by the encoder with respect to the true magnetic pole position, ω _r is the rotational angular velocity (rad / sec) in the operating state, and V _dF and V _dR are forward rotation and The d-axis voltage (V), i _dF , i _dR in the reverse rotation is the d-axis current (A) in the forward rotation and the reverse rotation, respectively, and i _qF , i _qR are the q-axis in the forward rotation and the reverse rotation, respectively. Current (A), ω is electrical angular velocity (rad / sec), R is armature winding resistance (Ω), L _q is q-axis inductance (H), K _E is induced voltage coefficient (V / (rad / sec) )
It is.

(Equation 1) is derived as follows.
The dq axis voltage equation when there is a magnetic pole position error ε in the steady state is shown as follows.

V _d = R ・ i _d −ω ・ L _q・ i _q −ω _r・ K _E・ sinε (Formula 2)
_{V q = ω · L d ·} i d + R · i q + ω r · K E · cosε ( Equation 3)

Substituting the d-axis currents i _dF and i _dR in forward rotation and reverse rotation into (Equation 2) and taking the difference, the following equation is obtained.

_{V dR -V dF = R (i} dR -i dF) -ωL q (i qR -I qF) + 2ω r K E sinε ( Equation 4)

When (Equation 4) is rearranged for sin ε, (Equation 1) is obtained.

(Step ST4) Cases are classified according to mechanically predicted mounting errors. That is, when the magnetic pole position error ε is less than π / 18, the process proceeds to step ST5, and otherwise, the process proceeds to step ST6.
(Step ST5) When the magnetic pole position error ε is less than π / 18, sin ε≈ε holds, so sin ε is set as the magnetic pole position error.
(Step ST6) When the magnetic pole position error ε exceeds π / 18, the value of ε corresponding to the value of sin ε is obtained with reference to the estimation table (trigonometric function table), and the value is set as the magnetic pole position error.
(Step ST7) The magnetic pole position error correction angle is stored as data.

FIG. 2 is a flowchart of a magnetic pole position correction method showing an embodiment of the present invention. This flow is a procedure for correcting the magnetic pole position in torque control and current control during normal operation. Hereinafter, this flow will be described step by step.
(Step ST8) The magnetic pole position correction value is taken in.
(Step ST9) The magnetic pole position detection value from the detector is taken in.
(Step ST10) The true magnetic pole position is obtained from the information from the detector and the correction value.
(Step ST11) True magnetic pole position information is output to the torque controller and current controller.

  FIG. 3 is a control block diagram of a drive device for a permanent magnet motor incorporating a device for executing the magnetic pole position error correction method of the present invention. In the figure, block 1 is a magnetic pole position error estimation calculation block, and is a control block that estimates and calculates a magnetic pole position error angle and stores the magnetic pole position error angle as a correction value in the procedure shown in the flowchart of FIG. This mode is implemented as a magnetic pole position error estimation calculation mode. Block 2 is a magnetic pole position correction block, and is a control block that adds the correction values calculated in block 1 as correction values to the torque controller and current controller that are sequentially calculated during normal operation.

  The present invention is useful as a method and apparatus for correcting a magnetic pole position error of a permanent magnet motor.

It is a flowchart of the magnetic pole position error estimation method which shows the Example of this invention. It is a flowchart of the magnetic pole position correction method which shows the Example of this invention. It is a control block diagram of the drive apparatus of the permanent magnet electric motor which shows the Example of this invention.

Claims (3)

  In a magnetic pole position error correction method for a permanent magnet motor that corrects a magnetic pole position error of a permanent magnet motor provided with an encoder for detecting a magnetic pole position, the permanent magnet motor is operated in an arbitrary state to be rotated in a forward direction and a reverse direction. Measuring a d-axis current, a q-axis current, and a d-axis voltage, estimating a magnetic pole position error of the permanent magnet motor based on the rotation speed, the voltage, and the current measurement value; and the permanent magnet motor A method of correcting a magnetic pole position error of a permanent magnet motor, comprising: taking a value obtained by correcting a magnetic pole position detected by the encoder with a magnetic pole position error of the current controller and a torque controller as true magnetic pole position information. The magnetic pole position error correction method for a permanent magnet motor according to claim 1, wherein the following formula is used for estimation of the magnetic pole position error angle.
sinε = {(V _dR −V _dF ) −R (i _dR −i _dF ) + ωL _q (i _qR −i _qF )} / {2 · ω _r · K _E }
Where ε is the error angle (rad) of the magnetic pole position detected by the encoder with respect to the true magnetic pole position, ω _r is the rotational angular velocity (rad / sec) in the operating state, and V _dF and V _dR are forward rotation and The d-axis voltage (V), i _dF , i _dR in the reverse direction rotation are the d-axis current (A) in the forward direction and the reverse direction, respectively, i _qF , i _qR are the shaft currents in the forward direction and the reverse direction, respectively. (A), ω is electrical angular velocity (rad / sec), R is armature winding resistance (Ω), L _q is q-axis inductance (H), K _E is induced voltage coefficient (V / (rad / sec)) And A drive device for a permanent magnet motor incorporating a device for executing the magnetic pole position error correction method for a permanent magnet motor according to claim 1.

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