JPH0843462A - AC equipment constant measurement method and its equipment - Google Patents

Abstract

(57) [Summary] [Purpose] It is to measure all necessary motor constants only under the condition of rotation stop of the motor, without requiring multiple measurement conditions and no-load tests. [Constitution] The q-axis voltage command value is set to zero by the motor constant calculator 7, the primary angular frequency command and the d-axis voltage command are set to predetermined values, or the d-axis voltage command value is set to zero, and the primary angular frequency command and the q-axis command are set. When the voltage command is set to a predetermined value and this signal is input to the coordinate converter 3 and converted into a three-phase voltage command signal, a current flows from the inverter 2 to the AC motor 1 by the three-phase voltage command signal. When this current is detected by the current detectors 4a and 4b and input to the coordinate converter 5, the coordinate converter 5 outputs a d-axis current component and a q-axis current component. Based on these output values and the voltage command value, the resistance component and the inductance component of the AC device are calculated, this is performed using two different primary angular frequencies, and the AC component is calculated from the calculation results of the resistance component and the inductance component for each frequency. Find the constant of the device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for measuring constants of alternating current equipment, and more particularly to a method of measuring constants of alternating current equipment for measuring a constant of a motor used for setting a control constant in a vector controller of an alternating current motor. Regarding the device.

[0002]

2. Description of the Related Art When controlling an AC electric motor using a vector controller, it is necessary to set a control constant based on the constant of the target AC electric motor. Therefore, conventionally, the control constant is set based on the design value of the motor constant, or the necessary motor constant is measured by the resistance measurement test, the no-load test, and the constraint test, and the control constant is set from this measurement result. The method has been adopted. However, in the former method that uses the design value of the electric motor, a control calculation error occurs due to the mismatch between the design value and the actual value, and the readjustment is unavoidable after setting the control constant. On the other hand, in the latter method that uses the measurement results obtained by various measurement tests, it is necessary to perform a plurality of different tests such as the operation of the motor without a load, and the preparatory work for performing various measurements. Becomes complicated. Therefore, as a means for dealing with these problems, there is one described in JP-A-62-262697. This is the state in which the motor is connected to the inverter controller, the motor constant is measured from the voltage command value and current detection value when various measurement conditions are given,
The control constant is set according to this measurement result,
The DC resistance excites the primary resistance (r ₁ ), the three-phase AC excitation excites the primary and secondary combined resistance (r _σ = r ₁ + r ₂ ′), and the primary and secondary combined leakage inductance (L _σ = l ₁ +). l ₂ ')
Further, the mutual inductance (M ′) is measured by the constant speed operation without load.

[0003]

However, the conventional method is complicated because it requires measurement under a plurality of conditions. Especially M '
No load operation must be performed in the above measurement, and the electric motor needs to be operated separately from the load, so the preparation work for the measurement is complicated.

An object of the present invention is to provide an electric motor constant measuring method and apparatus capable of measuring all necessary electric motor constants only under the condition of stopping the rotation of the electric motor.

[0005]

The above object is to give a signal of a predetermined value to the primary angular frequency command and the d-axis voltage command, or to give the d-axis voltage command value under the condition that the q-axis voltage command value is zero. Under the condition that zero is given, a signal of a predetermined value is given to the primary angular frequency command and the q-axis voltage command, and the three-phase voltage applied to the AC device is controlled accordingly. The q-axis current component is detected, the resistance component and the inductance component of the AC device are calculated based on these detection values and the voltage command value, and this is performed using two different primary angular frequencies, and the resistance component for each frequency is calculated. It is achieved by obtaining the constant of the AC device from the calculation result of and the inductance component.

[0006]

According to the present invention, the q-axis voltage command value is set to zero and a signal of a predetermined value is given to the primary angular frequency command and the d-axis voltage command, or the d-axis voltage command value is set to zero and the primary angular frequency command is set. q
When a signal of a predetermined value is given to the shaft voltage command, a three-phase alternating current flows through the motor winding, the d-axis current component and the q-axis current component at this time are detected, and the motor constant is measured based on this detected value. You can get the value. In this case, the relationship between the d-axis current component and the q-axis current component and the command voltage is expressed by a function of the motor constant and the excitation frequency. Therefore, by performing measurement using two different frequencies and solving the simultaneous equations based on this relational expression, all necessary motor constants can be obtained only under the condition of rotation stop.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit configuration diagram of a constant measuring device for an AC device showing an embodiment when the present invention is applied to a system for driving an AC motor by a PWM inverter. In FIG. 1, an AC motor 1 is an AC device to be measured, and a PWM inverter 2 is connected to it. The PWM inverter 2 includes a switching element (not shown) such as a transistor, and has a three-phase voltage command signal V
A PWM signal generating means (not shown) for generating a three-phase PWM signal by comparing _1u *, _V1v *, and _V1w * with a carrier wave is provided, and an AC voltage of a variable frequency is supplied to the AC motor 1 according to the PWM signal. It is designed to be supplied to. The three-phase voltage command signals V _1u *, V _1v *, V _1w * are generated by the coordinate converter 3. The coordinate converter 3 calculates three-phase voltage command signals V _1u *, V _1v *, V _1w * from the d-axis voltage command V _1d *, the q-axis voltage command V _1q *, and the primary angular frequency command ω ₁ *. Is configured. On the other hand, a current detector 4a for detecting a U-phase current and a current detector 4b for detecting a W-phase current are provided in the line connecting the PWM inverter 2 and the AC motor 1, and the detection by each detector is performed. Electric current is supplied to the coordinate converter 5. The coordinate converter 5 includes current detectors 4a and 4b.
_Is configured as current component generation means for generating a d-axis current component I _1d and a q-axis current component I _1q represented by the d and q axes from the detected current and the primary angular frequency command ω ₁ *. A signal related to the current component is supplied to the vector controller 6 with the auto tuning function. The vector control device 6 is
An electric motor constant calculator 7, a control constant calculator 8, and a vector controller 9 are provided. The electric motor constant calculator 7 constitutes electric motor constant calculating means for calculating a constant of the electric motor based on the current components I _1d and I _1q from the coordinate converter 5, and
The q-axis voltage command V _1q * is set to zero, and the primary angular frequency command ω ₁ * and the d-axis voltage command V _1d * are set to predetermined values. The control constant calculator 8 is configured to calculate the control constant of the vector controller 9 based on the electric motor constant calculated by the electric motor constant calculator 7. The vector controller 9 is a control constant calculator 8
The primary voltage command V _1d *, V according to the control constant calculated in
It is configured to control signals such as _1q * and primary angular frequency command ω ₁ *. In this embodiment, the vector controller 9 is disconnected at the time of measurement, the q-axis voltage command V _1q * is set to zero as a measurement condition from the motor constant calculator 7, and the primary angular frequency command ω ₁ * and the d-axis voltage command V _1d * are set. As a signal and input to the coordinate converter 3.

Next, the measurement of the combined primary and secondary resistance r _σ of the motor constant, the combined primary and secondary leakage inductance L _σ , the secondary resistance r ₂ 'and the secondary time constant T _{2 under} the above measurement conditions. The method will be described. In the following mathematical expressions, I _1d : d-axis current component, I _1q : q-axis current component V _1d : d-axis voltage component, V _1q : q-axis voltage component φ _2d : d-axis secondary magnetic flux component φ _2q : q Axial secondary magnetic flux component ω ₁ : Primary angular frequency ω _re : Motor speed ω _s : Slip angular frequency T ₂ : Secondary side time constant r _σ : Primary and secondary combined resistance r ₂ ': Secondary resistance L _σ : A combined primary and secondary leakage inductance M ′: Mutual inductance L ₂ : Secondary self-inductance. First, the state equation of the induction motor is as follows (1)
It becomes an expression.

[Equation 1] In the equation (1), the relational expression in the steady state is the equation (2).

[Equation 2] Here, since the secondary magnetic flux cannot be measured, if this is eliminated from the equation (2), the following equations (3) and (4) can be obtained.

(Equation 3)

[Equation 4] As measurement conditions, V _1q = V _1q * = 0, V _1d = V _1d *, ω ₁
= Ω ₁ *, ω _re = 0 (ω _s = ω ₁ −ω _re = ω ₁ ), that is, when the condition for three-phase AC excitation when rotation is stopped is set, the following (5) and (6) The formula holds.

(Equation 5)

(Equation 6) ^ ^ Here, the parameters r _σ and L _σ are changed to the following (7),
Formula (8) is set.

(Equation 7)

(Equation 8) Since M ′ = r ₂ ′ T ₂ , the equations (5) and (6) become the following equations (9) and (10) by using the equations (7) and (8).

[Equation 9]

[Equation 10] ^ ^ By combining equations (9) and (10),
The measurement formulas for r _σ and L _σ are the following formulas (11) and (12).

[Equation 11]

(Equation 12)

Next, three-phase AC excitation is carried out using two different frequencies, and at each frequency Using two different frequencies, ω ₁ * α and ω ₁ * β, (1
Measured from formulas 1) and (12) It becomes an expression.

(Equation 13) By solving the simultaneous equations represented by the equation (13), the required motor constant can be obtained. First, by taking the difference between the values of the obtained respective parametric variables, the values shown by the following equations (14) and (15) are obtained.

[Equation 14]

(Equation 15) Looking at equations (14) and (15), since only T ₂ and r ₂ ′ are included, by solving the simultaneous equations consisting of equations (14) and (15), T ₂ and r ₂ ′ are 16), (17)
It is represented by a formula.

[Equation 16]

[Equation 17] Then, using the obtained T ₂ and r ₂ ′, r _σ and L _σ are obtained, and are expressed by the following equations (18) and (19).

(Equation 18)

[Formula 19] Also, since M ′ = r ₂ ′ T ₂ , the obtained T ₂ ,
'using the, M' r ₂ can be obtained.

The calculation of the electric motor constants described above is performed in the electric motor constant calculator 7. Since these calculations are automatically performed by using a microprocessor, the contents of the program will be described below with reference to the flowchart of FIG. In FIG. 2, first, in block 21, V _1q * = 0, ω ₁ *, V
_A predetermined value is set to _1d *, the converter output voltage is controlled accordingly, and the voltage is applied to the motor. Then block , , At the T ₂ from (16) (17) calculates the r ₂ 'from the equation, at block 25 the r _sigma from (18), (19)
Calculate L _σ from the equation. The above is the measurement principle. Therefore, under the measurement condition of three-phase AC excitation, measurement is performed using measurement signals of arbitrary two different frequencies, and the simultaneous equations are solved to obtain necessary motor constants r _σ , L _σ , and r.
₂ ', T ₂ can be measured. In this embodiment, the q-axis voltage command value is set to zero and a signal is given to the d-axis voltage command value. However, when the measurement conditions of the present invention are applied, the d-axis voltage and the q-axis voltage are Since the relational expression of the current is represented by the same expression, the d-axis voltage command value is set to zero,
Even if a signal is given to the q-axis voltage command value, various motor constants can be measured in the same manner.

Further, various motor constants obtained by the above-described measuring method are stored in the storage element and used for setting the control calculation constants of the vector controller as shown in FIG. In the vector controller shown in FIG. 3, in addition to the PWM inverter 2, the coordinate converters 3, 5, and the current detectors 4a, 4b shown in FIG. 1, a speed detector 10, a speed commander 11, a speed controller 12, an excitation Current command device 13, current controller 14,
15, a slip angular frequency controller 16 and a non-interference controller 17 are provided. The speed controller 12 determines the speed command from the speed commander 11 and the detected speed ω from the speed detector 10.
A q-axis current command I _1q * according to the difference from _rm is generated. The current controller 15 outputs a q-axis voltage command V _1q * according to the deviation between the q-axis current command value I _1q * from the speed controller 12 and the q-axis current component I _{1 q} .
The current controller 14 is adapted to generate a d-axis voltage command V _1d * according to a deviation between the exciting current command I _1d * from the exciting current command device 13 and the d-axis current component I _1d . The slip angular frequency controller 16 is adapted to divide the q-axis current command value I _1q * from the speed controller 12 by the exciting current command I _1d * to generate a slip angular frequency command ω _s *. Then, the slip angular frequency command ω _s * is added to the rotation speed ω _rm detected by the speed detector 10, and is output as the primary angular frequency command ω ₁ *. In addition, the non-interference controller 17
Is configured to remove the interference component between the dq axes using the current components I _1d *, I _1q * and the primary angular frequency command ω ₁ *. In the vector control device having the above configuration, for example, the slip angular frequency controller 16 is used
_The following equation (20) is used to obtain _s *.

(Equation 20) When using the equation (20), the secondary side time constant T ₂ measured by the method described above is used. When setting the calculation constants in this manner, the control constants are calculated by the control constant calculator 8 based on the motor constants measured by the method described above, and the constants of the calculation program of the vector controller 9 are set. It is possible. Also, the current controllers 14, 1
5. Similarly, in the non-interference controller 17, the arithmetic constant can be set based on the measured electric motor constant.
The primary and secondary combined resistances r _σ and the primary and secondary combined leakage inductances L _σ measured by the above-described method are used for the current controllers 14 and 15, and the decoupling controller 17 includes the primary and secondary combined leakage inductances L _σ. The secondary combined leakage inductance L _σ , the secondary resistance r ₂ ′, and the secondary side time constant T ₂ are used.

Next, FIG. 4 is a circuit diagram of a constant measuring device for an AC device showing another embodiment of the present invention. In the embodiment shown in FIG. 1, the vector controller 6 having the electric motor constant calculator 7 and the control constant calculator 8 incorporated therein is used, but in the embodiment of FIG. The difference is that the motor constant calculator 7 and the control constant calculator 8 form an auto-tuning device 18. In FIG. 4, a setting signal is sent from the electric motor constant calculator 7 to the vector controller 9 so as to satisfy a predetermined measurement condition, and the vector controller 9 outputs a voltage command value according to the setting signal. Then, the d-axis current detection value and the q-axis current detection value at that time are sent from the vector controller 9 to the motor constant calculator 7, and the motor constant is measured from these detected values in the motor constant calculator 7 by the method described above. It Then, the control constant calculator 8 calculates the control constant based on the measured electric motor constant,
The control constant value is sent to the vector controller 9, and the constant of the arithmetic program of the vector controller is set. In addition,
In the embodiments of the present invention shown above, the constant current measuring method for the AC motor and the apparatus thereof have been described, but the AC generator and the transformer are also represented by the same equivalent circuit, so that the generator is the same method. It is possible to measure the constants of transformers and transformers.

[0013]

As described above, the prior art is complicated because it requires measurement under a plurality of conditions.
In particular, in the measurement of the mutual inductance M ′, since no-load operation is performed, it is necessary to operate the electric motor separately from the load, which makes preparation for measurement complicated, whereas according to the present invention, The required motor constant can be measured only under the condition that the rotation of the motor is stopped.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a constant measuring device for an AC device showing an embodiment of the present invention.

FIG. 2 is a flowchart of motor constant measurement according to the present invention.

FIG. 3 is a circuit configuration diagram of an induction motor vector control device.

FIG. 4 is a circuit configuration diagram of a constant measuring device for an AC device showing another embodiment of the present invention.

[Explanation of symbols]

 1 AC motor 2 PWM inverter 3 Coordinate converter 4a, 4b Current detector 5 Coordinate converter 7 Motor constant calculator 8 Control constant calculator 9 Vector controller

Claims (3)

[Claims] 1. A three-phase voltage command signal is generated in accordance with a d-axis voltage command, a q-axis voltage command, and a primary angular frequency command, and a three-phase voltage proportional to the three-phase voltage command is applied to an AC device, and the AC When the output current of the device is detected and the d-axis current component and the q-axis current component are detected according to the detected current and the primary angular frequency command, the primary angular frequency command and d A signal of a predetermined value is given to the axis voltage command, or a signal of a predetermined value is given to the primary angular frequency command and the q-axis voltage command under the condition that the d-axis voltage command value is zero.
According to this, the three-phase voltage is controlled, the d-axis current component and the q-axis current component flowing in the AC device at this time are detected, and the resistance component and the inductance component of the AC device are determined based on these detected values and the voltage command value. A constant measuring method for an AC device, which comprises performing a calculation, performing the calculation using two different primary angular frequencies, and obtaining a constant of the AC device from a calculation result of a resistance component and an inductance component for each frequency. 2. A three-phase voltage command signal generating means for generating a three-phase voltage command signal in accordance with a d-axis voltage command, a q-axis voltage command and a primary angular frequency command, and an AC voltage proportional to the three-phase voltage command. And an output current detecting means for detecting the output current of the AC device, and a current component detecting means for detecting the d-axis current component and the q-axis current component according to the detection current of the output current detecting means and the primary angular frequency command, The d-axis current component and the q-axis current component detected by the current component detection means, and the constant voltage calculation means for calculating the constant of the alternating current equipment based on the voltage command, the value of the q-axis voltage command Is set to zero and a signal of a predetermined value is given to the primary angular frequency command and the d-axis voltage command, or the d-axis voltage command value is set to zero and the primary angular frequency command and the q-axis voltage command are set. In A signal of a constant value is given, and the input voltage of the AC device is controlled accordingly. At this time, the resistance of the AC device is determined based on the d-axis current component and the q-axis current component detected by the current component detecting means and the voltage command value. Component and inductance component are calculated, this is performed using two different primary angular frequencies, and constants of the AC device are calculated from the calculation results of the resistance component and the inductance component for each frequency. apparatus. 3. The q-axis based on the difference between the q-axis current command and the q-axis current detection value and the difference between the d-axis current command and the q-axis current detection value based on the calculated constant of the AC device. A current controller that generates a voltage command and a d-axis voltage command, a slip angle frequency controller that generates a slip angular frequency command based on the d-axis current command and the q-axis current command, and a d-axis current command and q
A constant of an AC device comprising control constant calculating means for setting a control constant of a vector controller having a non-interference controller for removing an interference component between dq axes based on an axis current command and a primary angular frequency command measuring device.