JP2001103798A - Identification apparatus for constant of induction motor and control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an identification apparatus for the constant of an induction motor, by which the constant of the induction motor can be identified in a state that the induction motor is in stop, and by which the constant of the induction motor can be identified precisely even when the skin effect or the magnetic saturation of the induction motor is generated. SOLUTION: A high-frequency signal is superimposed on a motor-voltage command value, and the constant of a motor is identified on the basis of a motor current. At this time, a command voltage or current which generates a torque is set to 0. The constant of the motor is set over a wide range by taking into consideration that the value of the constant of the motor is changed when ths superimposed signal for identification generates the skin effect or the magnetic saturation of the motor according to a frequency or a place.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for identifying a motor constant (or a motor constant) while an induction motor is stopped.

[0002]

2. Description of the Related Art Conventionally, when an induction motor is controlled by vector control, the motor constant (for example, primary and secondary resistance, leakage inductance,
It is necessary to obtain the speed, magnetic flux, slip angular velocity, and the like by calculation from the secondary circuit time constant, and the like. A method for identifying these motor constants while the induction motor is stopped is disclosed in JP-A-6-273496. There is one disclosed in the gazette. According to these techniques, a high-frequency or AC signal is superimposed on a command voltage or current of a field component in a state where a command voltage or a current for generating a torque for stopping the motor is set to 0 and DC excitation is performed. This is a method of identifying a motor constant using a signal and a motor voltage or current at that time.

[0003]

However, in the above-mentioned conventional example, when a technique of measuring a motor constant from a motor current by superimposing a high-frequency signal on a motor voltage command value is used, the skin depends on the frequency to be superimposed and the place of superimposition. Since the value of the motor constant changes depending on the effect and the state of the magnetic saturation, there is a problem that a value significantly different from the motor constant used in the normal driving frequency region is identified. Therefore,
The present invention considers that when a motor constant is identified in a state where the induction motor is stopped, a value of the motor constant changes due to a skin effect or magnetic saturation caused by a superimposed signal for identification depending on frequency or location. It is another object of the present invention to provide an induction motor constant identification device and a control device capable of accurately identifying a motor constant.

[0004]

Means for Solving the Problems To achieve the above object, a constant identification device for an induction motor according to the present invention separates a motor current into a magnetic flux component (d-axis component) and a torque component (q-axis component). In a vector control induction motor constant identification device that obtains a response equivalent to a DC motor by independently controlling each of them, a constant measurement axis (test angle) located at an arbitrary angle (test angle) from a control magnetic flux axis (γ axis) of the motor. A test voltage signal generator for generating a voltage signal including an arbitrary frequency on the X axis) and a test voltage signal distribution for distributing an output of the voltage generator to a control magnetic flux axis (γ axis) and a control torque axis (δ axis) A voltage adder that adds the output of the test voltage signal distributor to the specified γ-axis voltage value and the specified δ-axis voltage value,
A first coordinate converter that converts the input current of the motor into a magnetic flux component γ current and a torque component δ current on a control reference coordinate, a second coordinate converter that converts the input current of the motor onto a constant measurement axis, A high-frequency component remover that removes high-frequency components from the γ and δ currents that are outputs of the first coordinate converter, a current controller that controls an output current of the high-frequency component remover to match a current command value, A test frequency component extractor for extracting the same frequency component as the test voltage signal from a current output from the second coordinate converter; and an impedance with respect to a test angle from the output current from the test frequency extractor and the high frequency test voltage. An impedance identifier for identifying the second coordinate converter; an impedance optimum value calculator for obtaining an optimum value from the impedance that changes with respect to the test angle; Includes power and power factor calculator for calculating the power factor from the current and the high frequency voltage is, the constant identifier for separating the resistance component and the inductance from the impedance identifier output and power factor calculator output. The invention according to claim 2 is characterized in that the induction motor constant identified by the induction motor constant identification device according to claim 1 is used. According to the constant identification device and the control device of the induction motor, a test voltage signal including an arbitrary frequency is applied to a constant measurement axis (X) located at an arbitrary angle from the control magnetic flux axis.
Axis), the test signal frequency component is extracted from the detected current of the induction motor, the impedance is identified as (voltage effective value / current effective value) of the test signal component, and the power factor is calculated by calculating the power factor. When separating and identifying the resistance component and the inductance component, the frequency of the test signal includes not only a single frequency but a wide range of frequencies, and the generation position is not limited to a specific position, for example, a control magnetic flux axis (γ axis) From 0 ±
Since it is generated in a range such as 90 °, it is possible to identify, select and set an optimum impedance which is not affected by the skin effect or the magnetic saturation.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a control block diagram of a constant identification device for an induction motor according to an embodiment of the present invention. FIG. 2 is an equivalent circuit diagram of the induction motor shown in FIG.
FIG. 3 is a simplified circuit diagram of an equivalent circuit of the induction motor shown in FIG. FIG. 4 is a diagram showing an identification result by the impedance identifier shown in FIG. FIG. 5 is a block diagram of the power factor calculator shown in FIG. In FIG. 1, 1 is an induction motor, 2
Is a voltage source P that generates a three-phase current applied to the induction motor 1.
It is a WM inverter. Reference numeral 3 denotes a 2 / 3-phase coordinate converter that converts a two-phase voltage into a three-phase voltage, 4 denotes a test voltage distributor that converts a test signal output to an arbitrary angle, and 5 generates a high-frequency fx voltage as a test signal. Test signal generator,
6 is an adder for adding the output of the test voltage divider 4 to the output of the current controller 7 is a current command i? ^*, I? ^* Voltage command from V.gamma ^*, a current controller for generating a V8 ^*, 9 denotes a current detector A first coordinate converter for converting the three-phase detection current from 16 to a two-phase current, and a feedback output of two-phase currents iγ and iδ by removing high-frequency components for testing from the output of the coordinate converter 9 using an LPF or the like. High frequency component remover. 10
Is a second coordinate converter for converting the detected current value of the current detector 9 into a constant measurement axis (X axis); 11 is a test frequency component extractor for extracting a component of the superimposed frequency fx by BPF or the like;
2 is the impedance Zx from the extracted test frequency component.
, A power factor calculator 13 for calculating a power factor φ from the output of the impedance identifier 12,
4 is an impedance optimum value calculator for selecting an impedance value, and 15 is a constant identifier for separating and identifying R and L.

Next, the operation will be described. The test signal generator 5 generates a voltage command value which is a component of an arbitrary high frequency fx. The γ component (magnetic flux component) of the voltage command value and the δ component (torque component) of the voltage command value, which are the outputs of the current controller 7, are represented by the following formula (1).

(Equation 1) A test signal generator output V _X from the test voltage divider 4 by any angle theta _t with respect to the voltage command value of the equation (1), as shown in the following equation (2),

(Equation 2) A material obtained by coordinate conversion to V _X gamma and V _X [delta], is added by adder 6. Any angle theta _t is set to 0 degrees around the γ axis, -
It changes from 90 degrees to 90 degrees at a fixed angle for a fixed sampling time. The current detected by the current detector 16 is coordinate-transformed by a first coordinate converter 9 into control coordinate axes, and the high-frequency component remover 8 is used.
Then, the same frequency component as the superimposed frequency fx is removed and fed back, and a deviation from each command value is taken, and current control is performed by the current controller 7. At the time of motor constant identification, an appropriate iγ ^* is instructed, and iδ ^* is a 0 current instruction so as not to generate torque. On the other hand, in the second coordinate converter 10,
Converts the current detected by the current detector 16 from the control coordinates constant measurement axis located at an arbitrary angle theta _t to (X-axis), extracts the same frequency components as the superposition frequency fx at the test frequency component extractor 11 I do. Assuming that the test voltage is Equation (1),
Current i _X of the superimposed frequency component extracted here can be expanded as Equation (3).

(Equation 3) Incidentally, I _X is (voltage V _X) in the formula / (impedance), R, L, respectively _{φ, I X = V X /} {R 2 + (2πf X t) 2} 1/2 φ = tan - is ^{1 (2πfL / R) R =} R S + R r L = Ll S + Ll r ··· (4). Here, in the equivalent circuit of the induction motor expressed on the X axis, when the test frequency is an appropriate high frequency, current flows to the secondary circuit without passing through the excitation circuit as shown in FIGS. . Therefore, on the X-axis, Rs + Rr (sum of primary resistance and secondary resistance) can be detected as resistance, and Llr + Lls (sum of primary leakage inductance + secondary leakage inductance) can be detected as inductance. Next, the extracted portion is input to the impedance identifier 12, and the impedance identifier 12 calculates the effective value | V _X | / |
The impedance Zx is output for each test angle θt from i _X |. As a result, it is possible to detect the impedance at a place affected by the saturation by the main magnetic flux and a place not affected by the saturation. FIG. 4 shows an example of the result of the detected impedance.
In the figure, the lower row shows the test angle θ _t , the right column shows the superposed frequencies fx, and the left column shows the impedance Zx.

As shown in FIG. 4, the impedance when the superimposed frequency fx is changed can also be detected. By considering the superimposed frequency and the test angle θt, the optimum impedance value used for driving the motor can be determined by the impedance identifier 12.
Optimum impedance value calculator 14 from the output Zx
Is calculated. The power factor calculator 13 calculates the power factor using a circuit as shown in FIG. In addition, sin (2πf _X t)
And a DC component i through a low-pass filter (LPF).
Extracting _XA, whereas, this is multiplied by cos (2 [pi] f _X t) to extract the DC component i _XB through the low-pass filter (LPF), to calculate the power factor φ as Equation (5). (Where the output Zx impedance identifier 12, the effective value of ^{_{iX = (i XA 2 + i}} XB 2) 1/2, as, by dividing the effective value of the voltage V _X at this value may be obtained ) Φ = π / 2 + tan ⁻¹ i _XB / i _XA (5) The constant identifier 15 uses the φ obtained by the power factor calculator 13 to calculate R, Separate and calculate L. R = Zxcosφ, L = Zxsinφ, (6) The separation of the primary resistance Rs and the secondary resistance Rr
Rs is already set and corrected by a compensation circuit or the like, for example, as in the method of JP-A-6-34724. If Rs has been identified in advance, the primary resistance Rs is subtracted from R to obtain a second order. The resistance Rr can be identified. When such a constant identification device is combined with a vector control device of an induction motor including a speed detector, an exciting current commander, a slip angle frequency controller, a non-interference controller, etc., the primary resistance, Accurate auto-tuning by identifying a motor constant such as a secondary resistance and a leakage inductance by a constant identification device becomes possible, and highly accurate vector control becomes possible.

[0008]

As described above, according to the present invention,
When identifying a motor constant from a motor current by superimposing a high-frequency signal on a motor voltage command value, the command voltage or current for generating torque is set to 0, and the superimposed signal for identification has a skin effect or magnetic saturation depending on the frequency or location. Is taken into account in consideration of the fact that the value of the motor constant changes due to the occurrence of, it is possible to identify the motor constant in a state where the induction motor is stopped, and to accurately identify the motor constant. There is an effect that can be done.

[Brief description of the drawings]

FIG. 1 is a control block diagram of a constant identification device for an induction motor according to an embodiment of the present invention.

FIG. 2 is an equivalent circuit diagram of the induction motor shown in FIG.

FIG. 3 is a simplified diagram of an equivalent circuit of the induction motor shown in FIG.

FIG. 4 is a diagram showing an identification result by the impedance identifier shown in FIG. 1;

FIG. 5 is a block diagram of a power factor calculator shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Induction motor 2 PWM voltage type inverter device 3 2 phase 3 phase converter 4 Test voltage distributor 5 Test signal generator 6 Voltage adder 7 Current controller 8 High frequency component remover 9 First coordinate converter 10 Second coordinate conversion Unit 11 Test frequency component extractor 12 Impedance identifier 13 Power factor calculator 14 Impedance optimum value calculator 15 Constant identifier 16 Current detector

Continued on the front page (72) Inventor Ikuma Murohita 2-1 Kurosaki Castle Stone, Yawatanishi-ku, Kitakyushu-shi, Fukuoka Inside Yaskawa Electric Co., Ltd. (72) Inventor Hideaki Iura 2-1 Kurosaki Castle Stone, Yawata-nishi-ku, Kitakyushu-shi, Fukuoka Stock F-term (reference) in Yaskawa Electric Corporation 5H576 BB10 CC05 DD02 DD04 EE01 EE11 FF05 GG04 HB02 JJ26 KK06 LL01 LL22 LL24 LL27

Claims (2)

[Claims] 1. A constant of a vector control induction motor that obtains a response equivalent to a DC motor by separating a motor current into a magnetic flux component (d-axis component) and a torque component (q-axis component) and independently controlling each component. A test voltage signal generator for generating a voltage signal including an arbitrary frequency on a constant measurement axis (X axis) located at an arbitrary angle (test angle) from a control magnetic flux axis (γ axis) of the motor; A test voltage signal distributor for distributing an output of the voltage generator to a control magnetic flux axis (γ axis) and a control torque axis (δ axis); and outputting the output of the test voltage signal distributor to a γ axis voltage command value and a δ axis voltage command. A voltage adder for adding each of the values, a magnetic flux component γ current and a torque component δ on the control reference coordinates of the input current of the motor.
A first coordinate converter for converting the current into an electric current, a second coordinate converter for converting the input current of the motor onto a constant measuring axis, and a high frequency component based on the γ and δ currents output from the first coordinate converter. A high-frequency component remover, a current controller that controls the output current of the high-frequency component remover to match the current command value, and the test voltage signal from the current that is the output of the second coordinate converter. A test frequency component extractor for extracting the same frequency component, an impedance identifier for identifying an impedance with respect to a test angle from an output current from the test frequency extractor and the high frequency test voltage, and an impedance that changes with respect to the test angle. An impedance optimum value calculator for obtaining an optimum value, a power factor calculator for calculating a power factor from a current output from the second coordinate converter and the high-frequency voltage, A constant identification device for an induction motor, comprising: a constant identifier for separating a resistance component and an inductance component from the impedance identifier output and the power factor calculator output. 2. A control device for an induction motor, characterized by using an induction motor constant identified by the induction motor constant identification device according to claim 1.