JP3099159B2 - Method and apparatus for measuring motor constants - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for measuring a motor constant, and more particularly to a method and an apparatus for measuring a motor constant suitable for measuring a motor constant required in a control device for vector-controlling an AC motor.

[0002]

2. Description of the Related Art When controlling an AC motor using a vector control device, it is necessary to set a control constant based on the constant of the target AC motor. For this reason, conventionally, a method of setting a control constant based on a design value of a motor constant, or measuring a required motor constant by a resistance measurement test, a no-load test, and a constraint test, and setting a control constant from the measurement result Has been adopted.

However, in the former method using the design value of the electric motor, a control calculation error occurs due to a mismatch between the design value and the actual value, and it is necessary to readjust after setting the control constant.

[0004] On the other hand, in the latter method using the measurement results obtained by various measurement tests, preparation work for performing various measurements is complicated, for example, an instrument for fixing the electric motor in the constraint test is required.

To cope with these problems, there is one described in Japanese Patent Application Laid-Open No. 62-262697. In this method, with the motor connected to the inverter control device, the voltage command value and the current detection value when various measurement conditions are given are determined, the motor constant is measured according to these values, and the control constant is determined according to the measurement result. The primary resistance (r1) is set by DC excitation, and the combined primary and secondary resistance (rσ = r1 + r) by three-phase AC excitation.
2 ') and the combined primary and secondary leakage inductance (Lσ =
l1 + l2 '), and the mutual inductance (M') is measured by running at a constant speed with no load.

[0006]

However, in the prior art, when measuring the combined resistance rσ and the combined leakage inductance Lσ, a three-phase AC current flows through the motor, and a torque is generated. If the motor rotates during the measurement, the measurement accuracy deteriorates and an accurate value cannot be obtained as the motor constant.

If the measurement is performed with a very small current that does not cause the motor to rotate, the accuracy of the measurement similarly deteriorates due to the influence of harmonic components and noise of the inverter.

Further, since the measurement formula of the motor constant is derived from the approximation based on the high-frequency voltage, an error always occurs at a finite frequency.

When a high-frequency voltage is applied, the output voltage differs from the command voltage due to the influence of the pulse resolution and the increment error of the inverter, and as a result, the measurement accuracy deteriorates.

In the measurement of the mutual inductance M ', the primary resistance r1 and the combined leakage inductance Lσ measured earlier are used in the measurement formula, and the secondary resistance (r2) and the secondary time constant (T2) Since the calculation is performed using the previously measured values r1, rσ, and M ', there is a problem that the accuracy of the previous measurement greatly affects the measurement accuracy.

The present invention has been made in view of such circumstances, and it is an object of the present invention to accurately measure all necessary motor constants using a measurement signal of an arbitrary frequency while maintaining the motor in a stopped state. It is an object of the present invention to provide a method and an apparatus for measuring a motor constant that can be performed.

[0012]

According to the motor constant measuring method of the present invention, 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 power converter is proportionally generated. The output voltage is controlled and applied to the motor, and the output current is detected. When 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 the q-axis voltage Under the condition that each command value of the command is set to zero, an AC signal is given as a d-axis voltage command value, and a converter output voltage according to a three-phase voltage command signal generated based on this is applied to the electric motor. A d-axis current component flowing through the motor is detected, and the detected value is analyzed in accordance with Fourier expansion based on the AC signal, and two components of the AC signal are obtained to obtain a Fourier coefficient of the fundamental wave component. Performed with wavenumber, and obtaining the motor constants from the relationship between the current component value corresponding to the Fourier coefficient obtained from the frequency characteristics of the output current / input voltage at its Fourier coefficients and motor model.

Further, according to the motor constant measuring method of the present invention, 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 the output voltage of the power converter is controlled in proportion thereto. And applying the same to the motor, detecting the output current, and detecting the d-axis current component and the q-axis current component according to the detected current and the primary angular frequency command.
Under the condition that each command value of the primary angular frequency command and the d-axis voltage command is set to zero, an AC signal is given as a q-axis voltage command value, and a converter output voltage according to a three-phase voltage command signal generated based on this signal. Is applied to the motor, a q-axis current component flowing through the motor is detected at this time, and the detected value is analyzed according to Fourier expansion based on the AC signal, and the AC signal is used to obtain a Fourier coefficient of the fundamental wave component. Is performed using two frequencies, and the motor constant is obtained from the relationship between the Fourier coefficient obtained from the frequency characteristics of the output current / input voltage in the motor model and the corresponding current component value.

Further, according to the motor constant measuring method of the present invention, 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 the output voltage of the power converter is controlled in proportion thereto. And applying the same to the motor, detecting the output current, and detecting the d-axis current component and the q-axis current component according to the detected current and the primary angular frequency command.
Under the condition that each command value of the primary angular frequency command and the q-axis voltage command is set to zero, an AC signal including two frequency components is given as a d-axis voltage command value, and a three-phase voltage command generated based on the signal. A converter output voltage according to the signal is applied to the motor, a d-axis current component flowing through the motor at this time is detected, and the detected value is analyzed according to Fourier expansion based on the AC signal, and each basic component of the two frequency components is analyzed. It is characterized in that Fourier coefficients for wave components are obtained, and a motor constant is obtained from the relationship between the Fourier coefficients obtained from the frequency characteristics of the output current / input voltage in the motor model and the corresponding current component value.

Further, according to the motor constant measuring method of the present invention, 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 the output voltage of the power converter is controlled in proportion thereto. And applying the same to the motor, detecting the output current, and detecting the d-axis current component and the q-axis current component according to the detected current and the primary angular frequency command.
Under the condition that each command value of the primary angular frequency command and the d-axis voltage command is set to zero, an AC signal including two frequency components is given as a q-axis voltage command value, and a three-phase voltage command generated based on this. A converter output voltage according to the signal is applied to the motor, a q-axis current component flowing through the motor at this time is detected, and the detected value is analyzed according to Fourier expansion based on the AC signal, and each basic component of the two frequency components is analyzed. A Fourier coefficient for a wave component is obtained, and a motor constant is obtained from a relationship between the Fourier coefficient, the Fourier coefficient obtained from a frequency characteristic of an output current / input voltage in a motor model, and a corresponding current component value.

Further, the control constant setting method of the vector controller according to the present invention includes a q-axis current command, a d-axis current command, and a q-axis current component based on the motor constant obtained by any one of the motor constant measurement and measurement methods. And a control constant of a vector controller for generating a d-axis voltage command, a q-axis voltage command, and a primary angular frequency command based on the d-axis current component.

Further, the motor constant measuring apparatus according to the present invention comprises: 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; A power converter for applying an AC voltage proportional to the following to the motor; an output current detecting means for detecting an output current of the power converter; a d-axis current component and q according to a detected current of the output current detecting means and a primary angular frequency command. Current component generating means for generating an axis current component; measuring signal generating means for setting each command value of a primary angular frequency command and a q-axis voltage command to zero and providing an AC signal as a d-axis voltage command value; The method according to claim 1, wherein the three-phase AC voltage that changes according to the signal is applied to the motor based on the d-axis current component detected by the current component generation unit. Ri and having a motor constant calculating means for calculating a motor constant.

Further, the motor constant measuring apparatus according to the present invention comprises: 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; A power converter for applying an AC voltage proportional to the following to the motor; an output current detecting means for detecting an output current of the power converter; a d-axis current component and q according to a detected current of the output current detecting means and a primary angular frequency command. Current component generating means for generating an axis current component; measuring signal generating means for setting each command value of a primary angular frequency command and a d-axis voltage command to zero and providing an AC signal as a q-axis voltage command value; The method according to claim 2, wherein the three-phase AC voltage that changes according to the signal is applied to the motor based on the d-axis current component detected by the current component generation unit. Ri and having a motor constant calculating means for calculating a motor constant.

Further, the inverter device according to the present invention is characterized in that it comprises a vector controller whose control constant is set by the control constant setting method of the vector controller.

[0020]

In the motor constant measuring method having the above structure, the primary angular frequency command and the q-axis voltage command are set to zero, and d
When an AC signal is added as the shaft voltage command value, the three-phase AC current does not flow through the motor winding, the V-phase and W-phase currents become in-phase, and the single-phase AC current flows, so the motor stops without rotating. State can be maintained. When the rotation of the motor is stopped, a d-axis current component flowing through the motor is detected, and a measured value of the motor constant can be obtained based on the detected value. In this case, the detected value of the d-axis current component flowing through the motor is analyzed according to Fourier expansion based on the AC signal to obtain a Fourier coefficient of a fundamental wave component.
This is performed using two frequencies for the AC signal, and a motor constant is obtained from a relationship between the Fourier coefficient obtained from the frequency characteristic of the output current / input voltage in the motor model and the corresponding current component value. Under the same measurement conditions, it is possible to accurately obtain all the necessary motor constants using a measurement signal of any frequency that is less affected by the pulse resolution of the inverter and the increment error, which are the causes of the deterioration in accuracy. it can.

Further, in the motor constant measuring method having the above configuration,
When the command values of the primary angular frequency command and the q-axis voltage command are set to zero and an AC signal having two frequency components is added as the d-axis voltage command value, a three-phase AC current does not flow through the motor winding, and V Since the currents of the phase and the W-phase become in-phase and a single-phase alternating current flows, the motor can be kept stopped without rotating. When the rotation of the motor is stopped, a d-axis current component flowing through the motor is detected, and a measured value of the motor constant can be obtained based on the detected value. In this case, the detected value of the d-axis current component flowing through the motor is analyzed according to Fourier expansion based on the AC signal to obtain a Fourier coefficient for each of the fundamental components of the two frequency components. By obtaining the motor constant from the relationship between the Fourier coefficient and the current component value corresponding to the Fourier coefficient obtained from the frequency characteristic of the output current / input voltage in the motor model, the factor of accuracy deterioration is obtained under the same measurement condition. It is possible to accurately obtain all necessary motor constants by using a measurement signal of an arbitrary frequency that is less affected by the pulse resolution of the inverter and the increment error.

Further, in the motor constant measuring method having the above structure,
When each command value of the primary angular frequency command and the d-axis voltage command is set to zero, and an AC signal is added as a q-axis voltage command value,
The three-phase AC current does not flow through the motor winding, the U-phase becomes 0, the V-phase and W-phase currents have the same magnitude and opposite phases, and the single-phase AC current flows, so the motor stops without rotating. State can be maintained. When the rotation of the motor is stopped, a d-axis current component flowing through the motor is detected, and a measured value of the motor constant can be obtained based on the detected value. In this case, the detected value of the q-axis current component flowing through the motor is analyzed according to Fourier expansion based on the AC signal to obtain a Fourier coefficient of a fundamental wave component. This is performed using two frequencies for the AC signal, and a motor constant is obtained from a relationship between the Fourier coefficient obtained from the frequency characteristic of the output current / input voltage in the motor model and the corresponding current component value. Under the same measurement conditions, it is possible to accurately obtain all the necessary motor constants using a measurement signal of any frequency that is less affected by the pulse resolution of the inverter and the increment error, which are the causes of the deterioration in accuracy. it can.

In the motor constant measuring method having the above-described structure,
When the command values of the primary angular frequency command and the d-axis voltage command are set to zero and an AC signal having two frequency components is added as the q-axis voltage command value, a three-phase AC current does not flow through the motor winding, and U The phase becomes 0, the V-phase and W-phase currents have the same magnitude and opposite phases, and a single-phase AC current flows, so that the motor can be kept stopped without rotating. And
When the rotation of the motor is stopped, a d-axis current component flowing through the motor is detected, and a measured value of the motor constant can be obtained based on the detected value. In this case, the detected value of the q-axis current component flowing through the motor is analyzed in accordance with Fourier expansion based on the AC signal, and a Fourier coefficient is obtained for each fundamental component of the two frequency components. By obtaining the motor constant from the relationship between the Fourier coefficient and the current component value corresponding to the Fourier coefficient obtained from the frequency characteristic of the output current / input voltage in the motor model, the factor of accuracy deterioration is obtained under the same measurement condition. It is possible to accurately obtain all necessary motor constants by using a measurement signal of an arbitrary frequency that is less affected by the pulse resolution of the inverter and the increment error.

[0024]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing an embodiment when the motor constant measuring method of the present invention is applied to a system for driving an AC motor by a PWM inverter. In FIG. 1, a PWM inverter 2 is connected to an AC motor 1 to be measured. The PWM inverter 2 includes a switching element such as a transistor, and further includes a PWM signal generating unit that generates a three-phase PWM signal by comparing the three-phase voltage command signals V1u *, V1v *, V1w * with a carrier wave. , And a PWM signal to supply an AC voltage having a variable frequency to the AC motor 1. The three-phase voltage command signals V1u * to V1w * are generated by the coordinate converter 3. The coordinate converter 3 calculates a primary voltage command V1d * as a d-axis voltage command and q
Three-phase voltage command signals V1u *, V1v *, V1w from primary voltage command V1q * and primary angular frequency command ω1 * as shaft voltage commands.
* Is configured to calculate

[0026]

(Equation 1)

On the other hand, the PWM inverter 2 and the AC motor 1
A current detector 4 for detecting a U-phase current
A current detector 4b for detecting a and W-phase currents is provided, and currents detected by the current detectors 4a and 4b are supplied to the coordinate converter 5.

The coordinate converter 5 calculates the following equation (2).
Current detected by current detectors 4a and 4b and primary angular frequency command ω
The biaxial d-axis current components I1d, q represented by d and q axes from 1 *
It is configured as current component generation means for generating the axial current component I1q, and a signal related to each current component is supplied to a vector control device 6 having an auto tuning function.

[0029]

(Equation 2)

The vector control device 6 comprises a motor constant calculator 7, a control constant calculator 8, and a vector controller 9.

The motor constant calculator 7 constitutes motor constant calculation means for calculating a motor constant based on the current component I1d obtained from the coordinate converter 5, and includes a primary angular frequency command ω1 * and a q-axis voltage command. Set V1q * to 0 and
It is configured as a measurement signal generating means for generating an AC signal as the d-axis voltage command V1d *.

The control constant calculator 8 comprises a motor constant calculator 7
It is configured to calculate the control constant of the vector controller 9 based on the motor constant calculated in.

The vector controller 9 controls the primary voltage commands V1d * and V1q in accordance with the control constant calculated by the control constant calculator 8.
*, And is configured to control signals such as the primary angular frequency command ω1 *.

In the present embodiment, the vector controller 9 is disconnected at the time of measurement, the primary angular frequency command ω1 * is set to 0, the q-axis voltage command V1q * is set to 0, and the d-axis voltage command AC signal (V1d * = Vdsin
ωt) is input to the coordinate converter 3. In this case, when a signal according to the measurement condition is input to the coordinate converter 3, the output value from the coordinate converter 3 is calculated based on the equation (1).
An expression is obtained.

[0035]

(Equation 3)

From equation (3), it is understood that the voltages of the V phase and the W phase are in phase. Since the V-phase and W-phase voltages are in phase, the V-phase and W-phase currents are also in phase.

From the above relationship, when ω1 * is 0 and V1q * is 0, no three-phase AC current flows through the winding of the AC motor 1 and a single-phase AC current in which the V-phase and W-phase currents are the same is obtained. Will flow. For this reason, even if a large measurement signal is applied to the d-axis, no torque is generated in the AC motor 1 and the rotation of the AC motor 1 is maintained in a stopped state. When the above measurement conditions are applied, since the motor speed ωre is 0 and the slip angular frequency ωs is 0, for example, when an induction motor is used for the AC motor 1, in the model of the induction motor, ωr
Blocks related to e and ωs are omitted, and the induction motor model can be represented by a simple model as shown in FIG.

Next, the motor constants rσ, Lσ, r2 ′, T2
The method of measuring is described.

First, V1d * = Vdsinωt is input to the coordinate converter 3 as a measurement signal, and a voltage according to the input is applied to the AC motor 1. At this time, the current flowing through the AC motor 1 is detected by each of the current detectors 4a, 4b. And according to this detection current, d
An axial current component I1d is generated. Then, Fourier expansion is performed on the d-axis current component I1d with reference to the AC signal V1d * = Vdsinωt. The following equation (4) shows the fundamental wave component.

[0040]

(Equation 4)

Here, the period T is 2π / ω. In addition,
It is also possible to calculate the Fourier coefficient not only in one cycle of integration but also in any cycle.

Now, from FIG. 2, the transfer function until I1d is obtained from V1d * is expressed by the following equation (5).

[0043]

(Equation 5)

The AC signal Vdsinωt is added to the transfer function of equation (5).
Is added, the output current I1d is expressed by the following equation (6).

[0045]

(Equation 6)

The coefficient of sinωt in equation (4) and (6)
The coefficient of sinωt in the equation is the same, and cosωt in equation (4)
Should be equal to the coefficient of cosωt in the equation (6). Therefore, if simultaneous equations are made based on this condition, it is expressed by the following equation (7).

[0047]

(Equation 7)

In equation (7), for four unknown variables,
Since there are two equations, they cannot be solved as they are. Then, by performing two measurements using two different frequencies (ωα, ωβ), a quaternary simultaneous equation represented by the following equation (8) is obtained.

[0049]

(Equation 8)

By solving the simultaneous equations of equation (8),
The motor constants rσ, Lσ, r2 ′, and T2 are obtained.

Here, looking at equation (8), it is a very complicated equation, and it is difficult to directly solve the simultaneous equations of equation (8). So, by using parametric variables,
Equation (8) is easily solved.

Here, the parameters are represented by the following (9) and (10).
Expression.

[0053]

(Equation 9)

[0054]

(Equation 10)

From equations (9) and (10), rσ and Lσ are expressed by the following equations (11) and (12).

[0056]

[Equation 11]

[0057]

(Equation 12)

Rσ, L expressed by equations (11) and (12)
Substituting σ into equation (6) gives the following equation (13).

[0059]

(Equation 13)

The coefficient of sinωt in equation (4) and (1
The coefficient of sinωt in equation (3) matches, and cos in equation (4)
Since the coefficient of ωt and the coefficient of cos ωt in equation (13) should match, if a simultaneous equation is made based on this condition,
It is expressed by the following equation (14).

[0061]

[Equation 14]

By solving the simultaneous equations of the equation (14), the parameters are expressed by the following equations (15) and (16).

[0063]

(Equation 15)

[0064]

(Equation 16)

The above is applied to the quaternary simultaneous equations of the equation (8). The parameters are expressed by the following equations (17) to (20).

[0066]

[Equation 17]

[0067]

(Equation 18)

[0068]

[Equation 19]

[0069]

(Equation 20)

Then, the quaternary simultaneous equation of the equation (8) can be simply expressed as the following equation (21).

[0071]

(Equation 21)

From the equation (21), using the equations (15) and (16), the value of each parameter is calculated from the following equation (22) to the equation (25).
It is expressed by an equation.

[0073]

(Equation 22)

[0074]

(Equation 23)

[0075]

(Equation 24)

[0076]

(Equation 25)

Here, by taking the difference between the obtained parameter values based on the equations (17) to (20), the values shown in the following equations (26) and (27) are obtained.

[0078]

(Equation 26)

[0079]

[Equation 27]

Looking at equations (26) and (27), T2, r
Since only 2 ′ is included, T2 and r2 ′ are calculated by solving the simultaneous equations consisting of the equations (26) and (27).
8) and (29).

[0081]

[Equation 28]

[0082]

(Equation 29)

Then, using the obtained T2 and r2 ', r
When σ and Lσ are obtained, they are expressed by the following equations (30) and (31).

[0084]

[Equation 30]

[0085]

(Equation 31)

FIG. 3 shows a specific conceptual diagram of the measurement. As shown in FIG. 3, first, using the set values Vd, ωα, ωβ and I1d obtained according to the detection values of the current detectors 4a and 4b, the parameter values for each frequency are calculated from (22) to (2).
5) Measure according to the formula. Then, a difference between the obtained parameter values is obtained, and T2 and r2 'are calculated from these values as (2
8), Measured according to equation (29). Then, using the obtained measured values of T2 and r2 'and correcting the measured values obtained by equations (22) to (25) according to equations (30) and (31), rσ and Lσ are measured.

The above is the measurement principle. Therefore, under the same measurement conditions, measurement is performed using measurement signals of any two frequencies that are less affected by the pulse resolution of the inverter and the increment error, which are factors of accuracy deterioration, and by solving simultaneous equations, Required motor constants rσ, Lσ, r
2 ', T2 can be measured with high accuracy.

In the above embodiment, the measurement is performed twice using two different frequencies. However, an AC signal (V1d * = Vdsinωαt +
Vdsinωβt). In this case, the d-axis current component I1d is converted to the AC signal V1d * = Vdsin
The following equation (32) is obtained by performing Fourier expansion on the basis of ωαt + Vdsinωβt and focusing on each frequency component.

[0089]

(Equation 32)

As understood from the block diagram shown in FIG. 2, since the motor model at the time of measurement is linear, the output response to each frequency can be considered separately by the superposition theorem. Therefore, when the AC signal Vdsinωαt is added to the transfer function of the equation (5), the output current I
1d is expressed by the following equation (33).

[0091]

[Equation 33]

Further, the transfer function of the equation (5) has an AC signal Vds
When inωβt is added, the output current I1d becomes the following (3)
4) It is expressed by the equation.

[0093]

(Equation 34)

The coefficient of sinωαt in equation (32) matches the coefficient of sinωαt in equation (33), the coefficient of cosωαt in equation (32) matches the coefficient of cosωαt in equation (33), and (32) The coefficient of sinωβt in the equation should match the coefficient of sinωβt in equation (34), and the coefficient of cosωβt in equation (32) should match the coefficient of cosωβt in equation (34). Is obtained, a simultaneous equation of equation (8) is obtained, and the necessary motor constants rσ, Lσ, r2 ′, T2
Can be measured with high accuracy.

In the above embodiment, the case where the measurement signal is applied to the d-axis has been described. However, when the measurement conditions in the present invention are applied, since the d-axis and the q-axis are exactly the same model, the q-axis is used. Even if a measurement signal is added, various motor constants can be measured. In this case, the command values of the primary angular frequency command ω1 * and the d-axis voltage command V1d * are each set to 0, and an AC signal is given as the q-axis voltage command value.

Further, even if the measurement signals having the same phase are added to the d-axis and the q-axis, the combined vector direction is set as a new axis, for example, this axis is temporarily set as the d 'axis, and the axis orthogonal to this is set as the q' axis. Then, operations similar to those in the above-described embodiment are performed on the d ′ and q ′ axes, and can be equivalently handled.

The various motor constants obtained by the above-described measuring method are stored in a storage element and used for setting control operation constants of the vector control device as shown in FIG.

In the vector control device shown in FIG.
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 exciting current commander 13, a current controller 14, 15, a slip angular frequency controller 16, a non-interference controller 17, and the like.

The speed controller 12 generates a q-axis current command I1q * according to the difference between the speed command from the speed commander 11 and the speed detected by the speed detector 10.

The current controller 15 outputs a q-axis voltage command V1q * according to the deviation between the q-axis current command value I1q * from the speed controller 12 and the q-axis current component I1q.

The current controller 14 generates a d-axis voltage command V1d * according to a deviation between the exciting current command I1d * from the exciting current commander 13 and the d-axis current component I1d.

The slip angular frequency controller 16 is the speed controller 1
2 is divided by the exciting current command I1d * to generate a slip angular frequency command ωs *. Then, the slip angular frequency command ωs * is added to the rotational speed ωrm detected by the speed detector 10, and is output as a primary angular frequency command ω1 *.
The non-interference controller 17 is configured to compensate for the interference term using the current components I1d * and I1q * and the primary angular frequency command ω1 *.

In the vector control device having the above configuration, for example, when the slip angle frequency controller 16 determines the slip angle frequency command ωs *, the following equation (35) is used.

[0104]

(Equation 35)

When using the equation (35), the secondary time constant T2 as the motor constant measured by the method described above is used. When setting such operation constants,
It is possible to calculate the control constants in the control constant calculator 8 based on the motor constants measured by the method described above, and to set the constants in the calculation program of the vector controller 9.
Similarly, the current controllers 14, 15 and the non-interference controller 17 can also set operation constants based on the measured motor constants.

In the above-described embodiment, the vector control device 6 incorporating the motor constant calculator 7 and the control constant calculator 8 is used. However, as shown in FIG. Separately, an auto-tuning device 18 composed of a motor constant calculator 7 and a control constant calculator 8
Can function as In this case, a setting signal is sent from the motor constant calculator 7 to the vector controller 9 so as to satisfy predetermined measurement conditions, and the vector controller 9 outputs a voltage command value according to the setting signal. The detected value of the d-axis current at that time is transmitted from the vector controller 9 to the motor constant calculator 7.
The motor constant is measured by the motor constant calculator 7 from the detected d-axis current value by the method described above. Then, based on the measured motor constant, the control constant calculator 8
, And the control constant value is sent to the vector controller 9, and the constant setting of the operation program of the vector controller is performed.

[0107]

As described above, according to the present invention,
When applying the measurement signal to the AC motor, a measurement signal in which a single-phase AC current flows through the AC motor is used, so that the constant of the motor can be measured while the rotation of the motor is stopped. The measurement is performed using any two frequencies that have little influence on the factors such as the pulse resolution of the inverter and the increment error, and the current component I1d on the d-axis at that time is analyzed according to the Fourier expansion based on the AC signal. From the relationship between the Fourier coefficient of the fundamental wave component and the Fourier coefficient obtained from the frequency characteristic of the output current / input voltage of the motor model and the corresponding current component value,
All necessary motor constants can be measured with high accuracy.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a motor constant measuring apparatus showing one embodiment of the present invention.

FIG. 2 is a block diagram model of a motor during measurement.

FIG. 3 is a conceptual diagram of a motor constant measurement according to the present invention.

FIG. 4 is a circuit configuration diagram of an induction motor vector control device.

FIG. 5 is a circuit configuration diagram of a motor constant measuring apparatus showing another embodiment of the present invention.

[Explanation of symbols]

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

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01R 31/34 H02P 21/00

Claims (7)

(57) [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 an output voltage of a power converter is controlled in proportion to the signal to apply to a motor. When detecting the output current and detecting the d-axis current component and the q-axis current component according to the detected current and the primary angular frequency command, under the condition that each of the command values of the primary angular frequency command and the q-axis voltage command is zero. , An AC signal is given as a d-axis voltage command value, a converter output voltage according to a three-phase voltage command signal generated based on the d-axis voltage command value is applied to the motor, and a d-axis current component flowing through the motor at this time is detected. The value is analyzed in accordance with Fourier expansion based on the AC signal, and a Fourier coefficient of the fundamental wave component is obtained using two frequencies with respect to the AC signal. Motor constant measurement method characterized by determining the motor parameters from the relation between the current component value corresponding to the Fourier coefficient obtained from the frequency characteristics of the output current / input voltage at Dell. 2. 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 the output voltage of the power converter is controlled in proportion to the three-phase voltage command signal and applied to the motor. When detecting the output current and detecting the d-axis current component and the q-axis current component according to the detected current and the primary angular frequency command, under the condition that each of the primary angular frequency command and the d-axis voltage command is zero. , An AC signal is given as a q-axis voltage command value, a converter output voltage according to a three-phase voltage command signal generated based on the AC signal is applied to the motor, and a q-axis current component flowing through the motor at this time is detected. The value is analyzed in accordance with Fourier expansion based on the AC signal, and a Fourier coefficient of the fundamental wave component is obtained using two frequencies with respect to the AC signal. Motor constant measurement method characterized by determining the motor parameters from the relation between the current component value corresponding to the Fourier coefficient obtained from the frequency characteristics of the output current / input voltage at Dell. 3. A three-phase voltage command signal is generated according to a d-axis voltage command, a q-axis voltage command, and a primary angular frequency command, and the output voltage of the power converter is controlled in proportion to the three-phase voltage command signal and applied to the motor. When detecting the output current and detecting the d-axis current component and the q-axis current component according to the detected current and the primary angular frequency command, under the condition that each of the command values of the primary angular frequency command and the q-axis voltage command is zero. An AC signal including two frequency components is given as a d-axis voltage command value, and a converter output voltage according to a three-phase voltage command signal generated based on the d-axis voltage command value is applied to the motor, and a d-axis current component flowing through the motor at this time , And the detected value is analyzed in accordance with Fourier expansion based on the AC signal to obtain Fourier coefficients for each of the fundamental components of the two frequency components. Motor constant measurement method of the relationship between the current component value and the corresponding Fourier coefficient obtained from the frequency characteristics of the output current / input voltage in the model and obtains the motor parameters. 4. 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 the output voltage of the power converter is controlled in proportion to the three-phase voltage command signal and applied to the motor. When detecting the output current and detecting the d-axis current component and the q-axis current component according to the detected current and the primary angular frequency command, under the condition that each of the primary angular frequency command and the d-axis voltage command is zero. , An AC signal including two frequency components as a q-axis voltage command value, and applying a converter output voltage according to a three-phase voltage command signal generated based on the q-axis voltage command signal to the motor, and at this time, a q-axis current component flowing through the motor , And the detected value is analyzed in accordance with Fourier expansion based on the AC signal to obtain Fourier coefficients for each of the fundamental components of the two frequency components. Motor constant measurement method characterized by determining the motor parameters from the relation between the current component value corresponding to the Fourier coefficient obtained from the frequency characteristics of the output current / input voltage at Dell. 5. A q-axis current command and a d-axis current command, and a q-axis current component and a d-axis current component, based on a motor constant obtained by the measurement method according to any one of claims 1 to 4. A method for setting a control constant of a vector controller, comprising: setting a control constant of a vector controller for generating a d-axis voltage command, a q-axis voltage command, and a primary angular frequency command. 6. 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 supplies an AC voltage proportional to the three-phase voltage command to the electric motor. A power converter to be applied, output current detection means for detecting an output current of the power converter, and a current component for generating a d-axis current component and a q-axis current component in accordance with a detection current of the output current detection means and a primary angular frequency command. Generating means;
Measurement signal generating means for setting each command value of the primary angular frequency command and the q-axis voltage command to zero and providing an AC signal as a d-axis voltage command value, and applying a three-phase AC voltage varying according to the AC signal to the motor. As a result, based on the d-axis current component detected by the current component generation unit,
An electric motor constant measuring device, comprising: electric motor constant calculating means for calculating an electric motor constant by the method according to claim 1. 7. 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 supplies an AC voltage proportional to the three-phase voltage command to the electric motor. A power converter to be applied, output current detection means for detecting an output current of the power converter, and a current component for generating a d-axis current component and a q-axis current component in accordance with a detection current of the output current detection means and a primary angular frequency command. Generating means;
Measurement signal generating means for setting each command value of the primary angular frequency command and the d-axis voltage command to zero and providing an AC signal as a q-axis voltage command value, and applying a three-phase AC voltage varying according to the AC signal to the motor. As a result, based on the d-axis current component detected by the current component generation unit,
An electric motor constant measuring device, comprising: electric motor constant calculating means for calculating an electric motor constant by the method according to claim 2.