JP2000050700A - Control method for synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically measure the motor constant of a synchronous motor with control equipment. SOLUTION: An AC current containing a DC component is made to flow in an arbitrary direction ((h)-axis). A current in a direction ((v)-axis) perpendicular to the arbitrary direction is made 0. When a synchronous motor is stopped, an inductance component Lh, and a resistance component Rh are obtained from amplitude and phase of AC component of the (h)axis current and amplitude and phase of AC component of the (h)axis voltage, and a resistance component Rdc is obtained from magnitude of DC component of the (h)-axis current and magnitude of DC component of the (h)-axis voltage. A DC current is made to flow in the (h)-axis, and an AC current is made to flow in the (v)-axis. When a synchronous motor is stopped, an inductance component Lv and a resistance component Rv are obtained from amplitude and phase of AC component of the (v)-axis current and amplitude and phase of AC component of the (v)-axis voltage. An inductance component Lh is set and stored as an inductance Ld, an inductance component Lv is set and stored as an inductance Lq, and the resistance component Rdc or the mean value of a resistance component Rh, the resistance component Rv and the resistance component Rdc is set and stored as a winding resistance R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for controlling a permanent magnet type synchronous motor, and more particularly to a method for controlling a synchronous motor which can be easily adjusted with high accuracy.

[0002]

2. Description of the Related Art Conventionally, a winding resistance which is a motor constant of a permanent magnet type synchronous motor is measured by a DC test, and an inductance Ld of a d-axis is limited to a d-axis current only when the permanent magnet type synchronous motor is fixed. Measured by a restraint test with alternating current, q
The shaft inductance Lq was measured by a constraint test in which an AC current was applied only to the q-axis current with the permanent magnet synchronous motor fixed, and the measured motor constant was manually input to the control device.

[0003]

In order to control a permanent magnet type synchronous motor with high accuracy, a value of a motor constant of the permanent magnet type synchronous motor may be required. But for example d
When measuring the inductance Ld of the shaft and the inductance Lq of the q-axis, a tool for fixing the permanent magnet synchronous motor so that it does not rotate is necessary. Without such a test device, the permanent magnet synchronous motor can be measured with high accuracy. I could not control it. Also, the armature resistance and the d-axis inductance Ld and q
Since it is measured separately from the shaft inductance Lq,
There was a problem that it took time.

When measuring the d-axis inductance Ld and the q-axis inductance Lq, the direction of the permanent magnet is required. FIG. 2 shows an example of a signal output from a position detector that detects the direction of a permanent magnet. Since the position detector outputs three pulse signals having phases different from each other by 120 degrees depending on the direction of the permanent magnet, the position of the permanent magnet is detected by a combination of these three pulses. Usually, the correspondence between the combination of these three pulses and the direction of the permanent magnet is not known at first, so that the direction of the permanent magnet is not known and the motor constant cannot be measured. The present invention has been made in view of the above points, and aims to solve these drawbacks, to simultaneously measure the motor constant without using a test device, and to further understand the direction of the permanent magnet. An object of the present invention is to provide a synchronous motor control method that eliminates the inability to measure a motor constant.

[0005]

According to a first aspect of the present invention, there is provided a permanent magnet type synchronous motor, comprising: detecting or estimating a direction of a permanent magnet of the permanent magnet type synchronous motor; In the synchronous motor control method for controlling the primary current by dividing the primary current into a d-axis current component parallel to the d-axis direction and a q-axis current component perpendicular to the d-axis, An AC current containing a DC component is applied to the h-axis, the current in the direction v-axis perpendicular to the h-axis is set to 0, and after the rotor of the permanent magnet synchronous motor stops, the magnitude and phase of the AC component of the h-axis current are detected. The magnitude and phase of the AC component of the h-axis voltage of the magnet type synchronous motor are detected or estimated, and the inductance component Lh is obtained from the magnitude and phase of the AC component of the h-axis current and the magnitude and phase of the AC component of the h-axis voltage. I The inductance component Lh is set and stored as the inductance Ld in the d-axis direction, the DC component of the h-axis current is detected, and the DC component of the h-axis voltage is detected or estimated to determine the resistance component Rdc. After setting and storing the winding resistance of the synchronous motor, a DC current is supplied to the h-axis, an AC current is supplied to the v-axis, and the magnitude and phase of the AC component of the v-axis current after the rotor of the permanent magnet synchronous motor is stopped. The magnitude and phase of the AC component of the v-axis voltage of the permanent magnet synchronous motor are detected or estimated, and the inductance component Lv is obtained from the magnitude and phase of the AC component of the v-axis current and the magnitude and phase of the AC component of the v-axis voltage. , And the inductance component Lv is set and stored as the inductance Lq in the q-axis direction.

Next, as the winding resistance of the permanent magnet type synchronous motor, an AC current including a DC component is applied to the h-axis, and the h-axis current when the current of the v-axis is set to 0 as defined in claim 2. The resistance component Rh is obtained from the magnitude and phase of the AC component of the current and the magnitude and phase of the AC component of the h-axis voltage, and the DC current is passed through the h-axis and the AC current is passed through the v-axis. The resistance component Rv is determined from the magnitude and phase of the component and the magnitude and phase of the AC component of the v-axis voltage, and the average value of the resistance component Rh, the resistance component Rv, and the resistance component Rdc is determined as the winding resistance of the permanent magnet synchronous motor. In this case, the same effect as in claim 1 can be obtained in which the resistance component Rdc obtained from only the DC component is used as the winding resistance of the permanent magnet type synchronous motor. Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0007]

FIG. 1 is a block diagram showing an embodiment of the present invention according to the first aspect. Hereinafter, the details of the invention will be described with reference to the drawing. The power converter 4 supplies power to the permanent magnet synchronous motor 1. The voltage detector 2 outputs a primary voltage v1 applied to the permanent magnet synchronous motor 1. The current detector 3 outputs a primary current i1 flowing through the permanent magnet synchronous motor 1.

[0008] The Ld measuring means 8 receives the primary current i1 and the primary voltage v1, inputs an AC current including a DC component to the h-axis which is an arbitrary direction θg of the permanent magnet type synchronous motor 1, and outputs an AC current including a DC component in a direction perpendicular thereto. A control signal is output such that the current on the v-axis becomes 0, the h-axis current ih and the h-axis voltage vh are subjected to Fourier transform, and the magnitude and phase of the fundamental wave component of the h-axis current ih and the h-axis voltage vh The inductance component Lh and the resistance component Rh are determined from the magnitude and phase of the fundamental wave component, and the resistance component Rdc is determined from the magnitude of the DC component of the h-axis current ih and the magnitude of the DC component of the h-axis voltage vh.

The Lq measuring means 9 inputs the primary current i1 and the primary voltage v1, outputs a control signal such that a DC current flows on the h-axis and an AC current flows on the v-axis, and outputs the v-axis currents iv and v. The Fourier transform of the axial voltage vv is performed to obtain an inductance component Lv and a resistance component R from the magnitude and phase of the fundamental wave component of the v-axis current iv and the magnitude and phase of the fundamental wave component of the v-axis voltage vv.
Find v. The setting storage means 7 stores the inductance component L
h is set and stored as an inductance Ld in the d-axis direction parallel to the direction θr of the permanent magnet of the permanent magnet type synchronous motor 1,
The inductance component Lv is set and stored as the inductance Lq in the q-axis direction perpendicular to the direction θr of the permanent magnet. Similarly, the previously determined resistance component Rdc is set and stored as the winding resistance R of the permanent magnet synchronous motor 1.

[0010] The torque controller 6 includes an inductance Ld and an inductance Lq set and stored in the setting storage means 7.
The winding resistance R is input, and a control signal for controlling the torque of the permanent magnet synchronous motor 1 is output. The switch 5 supplies a control signal output from the torque controller 6 to the power converter 4 in a normal case of controlling the torque of the permanent magnet type synchronous motor 1 to the power converter 4 to obtain the inductance component Lh, the resistance component Rh, and the resistance component Rdc. When the control signal output from the Ld measuring means 8 is provided to the power converter 4 and the inductance component Lv and the resistance component Rv are obtained, the control signal output from the Lq measuring means 9 is provided to the power converter 4.

The reason why the above problem can be solved by claim 1 of the present invention will be described below. FIG. 4 shows the relationship between the arbitrary direction θg of the permanent magnet type synchronous motor and the actual direction θr of the permanent magnet in coordinates, and between these directions,

[0012]

(Equation 1)

It is assumed that there is a position error Δθ. h-axis current i
When h is an AC current including a DC component and the v-axis current iv is zero,

[0014]

(Equation 2)

## EQU1 ## Here, I is a DC component, Ih
Is the peak value of the AC current, ωh is the angular frequency of the AC current, and t is the time. Actual d-axis current id and q-axis current iq
Is

[0016]

(Equation 3)

## EQU1 ## The torque type of the permanent magnet synchronous motor is

[0018]

(Equation 4)

Therefore, the torque of the permanent magnet type synchronous motor when the current flows as in equations (4) and (5) is

[0020]

(Equation 5)

Can be expressed as Obviously, the terms below the third term in the equation (7) are AC components, so that the average is zero. The first and second terms indicate that the torque has a DC component. When the position error Δθ is not zero, a torque is generated and the operation is performed so that the position error Δθ becomes 0 or 180 degrees. That is, by passing the DC current I in the arbitrary direction θg, the permanent magnet type synchronous motor is rotated and fixed until the direction θr of the permanent magnet coincides with the arbitrary direction θg, or the position error Δθ is fixed at 180 degrees. Can be.

The characteristic equation of the permanent magnet type synchronous motor is as follows.

[0023]

(Equation 6)

Can be expressed as Here, ω is a rotation speed of the permanent magnet synchronous motor, and p is a differential operator. When the permanent magnet-type synchronous motor is rotated until the direction θr of the permanent magnet coincides with the arbitrary direction θg by flowing the currents of equations (2) and (3), the position error Δθ becomes zero, and d in equation (4) The axis current id becomes equal to the h-axis current ih in the equation (2),
The q-axis current iq in the equation (5) becomes equal to the v-axis current iv in the equation (3). When the position error Δθ is 180 degrees, the sign of the d-axis current id in equation (4) is opposite to the h-axis current ih in equation (2), and the value of the q-axis current iq in equation (5) is The sign having the opposite sign is equal to the v-axis current iv in the equation (3). Further, since the direction θr of the permanent magnet of the permanent magnet type synchronous motor is fixed, the rotation speed ω of the permanent magnet type synchronous motor is zero, and the d-axis voltage vd of the expression (8) and the rotation speed ω of the expression (9) are obtained. q
The shaft voltage vq is given by the following equation.

[0025]

(Equation 7)

From equations (10) and (11), an equivalent circuit of the permanent magnet synchronous motor when the permanent magnet synchronous motor stops and the position error Δθ is zero is shown in FIG. When the position error Δθ is 180 degrees, only the direction of the d-axis current id is reversed, and the equivalent circuit is similarly represented in FIG.
Therefore, it can be seen from equation (10) that the d-axis inductance Ld and the winding resistance Rh can be calculated from the magnitude and phase of the AC component of the h-axis voltage vh and the magnitude and phase of the AC component of the h-axis current ih. Further, from equation (10), the h-axis voltage v
It can be seen that the winding resistance Rdc can be calculated from the magnitude of the DC component of h and the magnitude of the DC component of the h-axis current ih.

As described above, the h-axis and the v-axis are (2)
By flowing the currents shown in the equations (3) and (3), the inductance Ld of the d-axis and the winding resistance R can be simultaneously calculated, and the current is measured by fixing the permanent magnet type synchronous motor as in the conventional case. Without the need to automatically measure and set.

Similarly, the h-axis current ih is a DC current, and the v-axis current iv is an AC current.

[0029]

(Equation 8)

, The d-axis currents id and q that actually flow
The shaft current iq is

[0031]

(Equation 9)

From the equation (6), the torque of the permanent magnet type synchronous motor is

[0033]

(Equation 10)

Can be expressed as follows. Since the DC component of the torque in the equation (16) is the same as that in the equation (7), when the DC current I flows in the arbitrary direction θg, the permanent magnet type synchronous motor matches the permanent magnet direction θr with the arbitrary direction θg. Or Δθ is 1
It can be rotated and fixed to a position of 80 degrees. Therefore, the d-axis current id in equation (14) is equal to the h-axis current ih in equation (12), and the q-axis current iq in equation (15) is equal to (1
The v-axis current iv in equation 3) is also equal. Position error Δθ is 1
In the case of 80 degrees, the sign of the d-axis current id in equation (14) is opposite to the h-axis current ih in equation (12),
The sign of the q-axis current iq in the equation (15) is opposite to that of the equation (13).
It is equal to the v-axis current iv in the equation. Further, since the direction θr of the permanent magnet of the permanent magnet type synchronous motor is fixed, the rotation speed ω of the permanent magnet type synchronous motor is zero,
The d-axis voltage vd in the equation (8) and the q-axis voltage vq in the equation (9) are as follows.

[0035]

[Equation 11]

From equations (17) and (18), the equivalent circuits of the permanent magnet synchronous motor when the permanent magnet synchronous motor stops and the position error Δθ is zero are shown in FIGS. 3 and 4. . When the position error Δθ is 180 degrees, only the directions of the d-axis current id and the q-axis current iq are reversed, and the equivalent circuits are similarly shown in FIGS. 3 and 4. Therefore, it can be seen from Expression (18) that the q-axis inductance Lq and the winding resistance Rv can be calculated from the magnitude and phase of the AC component of the v-axis voltage vv and the magnitude and phase of the AC component of the v-axis current iv.

As described above, (1)
By flowing the currents shown in equations 2) and (13), q
The shaft inductance Lq and the winding resistance R can be calculated simultaneously, and it is possible to automatically measure and set the current without fixing the permanent magnet type synchronous motor as in the related art and measuring the current. Was.

Next, claim 2 will be described. As described above, when a predetermined current is applied to the h-axis and the q-axis, the rotor of the permanent magnet synchronous motor rotates, the h-axis matches the d-axis, and the v-axis changes to the q-axis.
Stop at a position that coincides with the axis, or stop at a position where the h-axis and the v-axis advance 180 degrees from the d-axis and the q-axis. By obtaining the value, setting and storing this value as the winding resistance of the permanent magnet type synchronous motor, and using it in combination with the inductances Ld and Lq described above, the same effect as in claim 1 can be obtained. Become.

According to the present invention, it is possible to set the control device without using a device for measuring the motor constant of the permanent magnet synchronous motor, so that the control device can be adjusted easily and with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is an example of an output signal of a position detector.

FIG. 3 is an equivalent circuit of the permanent magnet type synchronous motor at the time of stop.

FIG. 4 is an equivalent circuit of the permanent magnet synchronous motor at the time of stop.

FIG. 5 is a coordinate diagram illustrating the principle of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Permanent magnet synchronous motor 2 Voltage detector 3 Current detector 4 Power converter 5 Switch 6 Torque controller 7 Setting storage means 8 Ld measurement means 9 Lq measurement means

Claims (2)

[Claims] A primary current flowing through the permanent magnet synchronous motor is detected or estimated by detecting or estimating the direction of the permanent magnet of the permanent magnet synchronous motor.
(Hereinafter referred to as an axis) and a q-axis current component in a direction perpendicular to the d-axis (hereinafter referred to as a q-axis) in a synchronous motor control method. An AC current including a DC component is passed in an arbitrary direction (hereinafter, referred to as an h-axis), and a current in a direction perpendicular thereto (hereinafter, referred to as a v-axis) is set to 0, and after the rotor of the permanent magnet type synchronous motor stops, the h The magnitude and phase of the AC component of the shaft current are detected, and the magnitude and phase of the AC component of the h-axis voltage of the permanent magnet synchronous motor are detected or estimated. The inductance component Lh is obtained from the magnitude and phase of the AC component of the voltage, and the inductance component Lh is calculated as the inductance L in the d-axis direction.
d, the DC component of the h-axis current is detected, and the DC component of the h-axis voltage is detected or estimated to obtain a resistance component Rdc, and the resistance component Rdc is used as the winding of the permanent magnet synchronous motor. A resistance is set and stored, a DC current is passed through the h-axis, an AC current is passed through the v-axis, and the magnitude and phase of the AC component of the v-axis current are detected after the rotor of the permanent magnet synchronous motor is stopped. Detecting or estimating the magnitude and phase of the AC component of the v-axis voltage of the permanent magnet synchronous motor, and calculating the inductance component Lv from the magnitude and phase of the AC component of the v-axis current and the magnitude and phase of the AC component of the v-axis voltage. And calculating and storing the inductance component Lv as the inductance Lq in the q-axis direction. 2. The magnitude and phase of the AC component of the h-axis current and the AC component of the h-axis voltage when an AC current containing a DC component is applied to the h-axis and the current on the v-axis is set to 0. The resistance component Rh is obtained from the magnitude and the phase of the current, and a DC current is applied to the h-axis and an AC current is applied to the v-axis.
The resistance component Rv is obtained from the magnitude and phase of the AC component of the axis current and the magnitude and phase of the AC component of the v-axis voltage, and the average value of the resistance component Rh, the resistance component Rv, and the resistance component Rdc is calculated by the permanent magnet type. 2. The method for controlling a synchronous motor according to claim 1, wherein the setting is stored as a winding resistance of the synchronous motor.