JP2003289700A - Induction motor control device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To simultaneously compensate a setting error of a secondary resistance and a mutual inductance in a control device of an induction motor. A rotating coordinate system converting means for converting a current flowing in an induction motor into an exciting current detection value and a torque current detection value of a rotating coordinate system, and a motor constant set value including a secondary resistance and a mutual inductance of the induction motor. Frequency voltage control means for controlling the frequency and voltage of the induction motor based on the difference between the excitation current command and the detection value of the excitation current and the difference between the torque current command and the detection value of the torque current. Current control means 101 and 106 for controlling the voltage applied to the motor; motor constant correction means 111 for correcting the set values of the secondary resistance and the mutual inductance based on the outputs of the excitation current control means 101 and the torque current control means 106
And characterized by having:

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction motor control device, and more particularly to an induction motor control device having a control system for controlling torque based on an estimated value of a motor constant.

[0002]

2. Description of the Related Art Vector control is known as a control method for controlling the torque generated by an induction motor with high accuracy. In vector control, a dq-axis current command or the like relating to torque control is calculated based on a set value of a motor constant set in the control device to control the induction motor.
Therefore, if there is an error between the set value of the motor constant and the actual motor constant, there is a problem that an error occurs in the generated torque. For example, it is known that the mutual inductance of an induction motor changes with the amount of excitation. It is known that the primary resistance and the secondary resistance of the induction motor change depending on the temperature. It should be noted that the changes in the primary resistance and the secondary resistance are correlated with each other, but it is also known that the influence of the error in the setting value of the secondary resistance is generally large.

In order to correct such an error between the set value and the actual value of the motor constant during operation, Japanese Patent Application Laid-Open No. 1-19488.
No. 3 proposes a method of correcting the set value of the secondary resistance so as to reduce the deviation of the command value corresponding to the d-axis voltage.
Further, Japanese Patent Laid-Open No. 4-193090 proposes a method of correcting the set value of the exciting inductance so as to reduce the deviation of the command value corresponding to the d-axis magnetic flux.

[0004]

By the way, in order to realize highly accurate torque control, it is necessary to simultaneously correct the errors of the secondary resistance and the mutual inductance among the motor constants. However, JP-A-1-194883 and JP-A-4-193090 do not consider the problem that the corrections interfere with each other when the correction methods are applied at the same time.

Further, when the set value of the secondary resistance is corrected by the method described in JP-A-1-194883, the polarity of the deviation of the command value corresponding to the d-axis magnetic flux is reversed in the region where the rotation speed is low. , There is a problem that the correction of the secondary resistance diverges.

A first object of the present invention is to simultaneously compensate for the setting error of the secondary resistance and the mutual inductance in the control device for the induction motor.

A second object is to stably compensate the setting error of the secondary resistance even in a region where the rotation speed is low.

[0008]

In order to solve the first problem, the control device for an induction motor according to the present invention detects a current flowing through the induction motor to detect an exciting current detection value and a torque current detection value in a rotating coordinate system. And a frequency voltage control means for controlling the frequency and voltage of the induction motor based on a set value of a motor constant including a secondary resistance and a mutual inductance of the induction motor. The control means controls the voltage applied to the induction motor based on the difference between the excitation current command and the detected excitation current, and the induction based on the difference between the torque current command and the detected torque current value. Torque current control means for controlling the voltage applied to the electric motor, the secondary resistance and the mutual inductor based on the outputs of the exciting current control means and the torque current control means. And a motor constant correcting means for correcting the set value of the resistance. This case is suitable when the rotation speed of the induction motor is higher than the set value.

In order to solve the second problem, the motor constant correction means sets the secondary resistance based on the output of the torque current control means when the rotation speed of the induction motor is lower than a set value. It is characterized in that only the value is corrected.

As described above, since the primary resistance of the induction motor correlates with the secondary resistance, the primary resistance can be corrected based on the correction amount of the secondary resistance.

With this configuration, in the region where the rotation speed is higher than the set value, for example, the d-axis magnetic flux error is estimated from the outputs of the exciting current control means and the torque current control means, and the d-axis magnetic flux error is estimated. By correcting the set value of the mutual inductance so as to reduce, the setting error of the mutual inductance can be reduced. Further, for example, by estimating the q-axis magnetic flux error from the outputs of the exciting current control means and the torque current control means, and correcting the set value of the secondary resistance so as to reduce the q-axis magnetic flux error, The resistance setting error can be reduced.

In this case, the q-axis electromotive force of the induction motor is obtained from the output of the torque current control means, and the q-axis electromotive force is multiplied by the slip frequency command and the set value of the secondary time constant to determine the mutual inductance. It is preferable to further correct the set value of. According to this, the interference that the correction of the secondary resistance gives to the correction of the mutual inductance can be compensated. Further, it is preferable to further correct the set value of the secondary resistance by the above-mentioned d-axis magnetic flux error. According to this, it is possible to compensate the interference that the correction of the mutual inductance gives to the correction of the secondary resistance.

On the other hand, in the region where the rotation speed is lower than the set value, the electromotive force of the q-axis of the induction motor is obtained from the output of the torque current control means, and the estimated value of the secondary resistance is corrected so as to reduce the electromotive force. Thereby, the estimation error of the secondary resistance can be reduced. Further, by correcting the estimated value of the primary resistance in the same manner as the correction of the secondary resistance, it is possible to further improve the estimation accuracy of the primary resistance, the secondary resistance and the mutual inductance.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on embodiments. FIG. 1 shows a configuration diagram of an embodiment of a frequency voltage control unit which is a main part of a control device for an induction motor according to the present invention. FIG. 2 shows an overall configuration diagram of an embodiment of a control device in which the present invention is applied to an induction motor for driving a vehicle.

As shown in FIG. 2, the DC power source 1 to the overhead line 2
A DC voltage is applied between the track 3 and the track 3. A current collector 4 attached to a vehicle (not shown) is provided in contact with the overhead wire 2 and is freely slidable. The starter 3 is provided with wheels 5 mounted on a vehicle (not shown) so as to freely roll. The current collector 4 is connected to the positive electrode at the power source end of the power converter 8 via the reactor 6, and the negative electrode at the power source end of the power converter 8 is connected to the wheel 5. Between the positive and negative electrodes of the power converter 8, a capacitor 7 that constitutes a filter together with the reactor 6 is connected. Thereby, the high frequency current flowing from the power converter 8 to the DC power supply 1 is reduced. Thus, the positive electrode of the DC power supply 1 is connected to the positive electrode of the power converter 8 via the overhead line 2, the current collector 4, and the reactor 6, and the negative electrode of the DC power supply 1 is connected via the track 3 and the wheels 5 to the power converter 8. Is connected to the negative electrode of.

On the other hand, an induction motor 9 is connected to the load end of the power converter 8. The current flowing through the induction motor 9 is detected by the current detector 10. The rotation speed of the induction motor is detected by the speed detector 11. The control device that controls the power converter 8 is configured by a microcontroller or the like, and when divided into major functions, it includes a current coordinate conversion unit 13, a frequency voltage control unit 14, a voltage coordinate conversion unit 15, and an integrator 16. To be done. In addition, in FIG. 2, the DC power supply 1, the overhead line 2 and the track 3 are installed on the ground, and the rest are mounted on the vehicle.

Next, the detailed configuration of the control device will be described. The frequency voltage control unit 14 provides the torque command T * and the magnetic flux command φ *, and the rotation speed ω detected by the speed detector 11.
r, the d-axis current (excitation current) detection value id and the q-axis current (torque current) detection value iq converted by the current coordinate conversion unit 13 are input. As a result, the frequency voltage control unit 14 follows the equation of state of the induction motor, and the d-axis voltage command vd * corresponding to the torque command T * and the magnetic flux command φ *.
And q-axis voltage command vq * and frequency command ω * are generated and output.

The frequency command ω * is input to the integrator 16,
The phase θ is output from the integrator 16 to the current coordinate conversion unit 13 and the voltage coordinate conversion unit 15. In the current coordinate conversion unit 13,
The U-phase current iu and the V-phase current i detected by the current detector 10 using the equation (1) based on the phase θ which is the output of the integrator 16.
The v and W-phase currents iw are subjected to rotational coordinate conversion to obtain the d-axis current detection value id and the q-axis current detection value iq.

[0019]

[Equation 1] In the voltage coordinate conversion unit 15, the d-axis voltage command vd * and the q-axis voltage command vq * output from the frequency voltage control unit 14 are calculated based on the phase θ which is the output of the integrator 16 by using the equation (2). Phase U-phase voltage command Vu *, V-phase voltage command Vv * and W
The phase voltage command Vw * is converted and output to the power converter 8.

[0020]

[Equation 2] The power converter 8 converts the DC voltage into a three-phase AC voltage according to the input voltage command and outputs the three-phase AC voltage to the induction motor 9. As a result, the induction motor 9 is drive-controlled by the frequency voltage controller 14.

Next, referring to FIG. 1, the frequency voltage controller 14 will be described.
Will be described in detail. As shown in FIG. 1, in the excitation current control unit 101, the input magnetic flux command φ * and the constant correction unit 11
From the correction setting value M ′ of the mutual inductance corrected in 1, the d-axis current command id * is calculated using the equation (3).

[0022]

[Equation 3] D-axis current command id output from the excitation current control unit 101
The deviation of * from the d-axis current detection value id is obtained by the subtractor 102. The deviation is subjected to proportional-plus-integral (PI) processing in the exciting current control unit 103, and the d-axis compensation voltage δvd
Is output to the voltage control unit 104. That is, the subtractor 10
2 and the exciting current control unit 103, the d-axis current command id *
Then, the d-axis compensation voltage δvd is obtained from the d-axis current detection value id using the equation (4), and the d-axis current command value id * is controlled so that the d-axis current detection value id matches. In the equation, K
pd and Kid are control gains, and s is a differential operator.

[0023]

[Equation 4] On the other hand, in the magnetic flux estimation unit 105, the input magnetic flux command φ *
From the above, the estimated magnetic flux value φ ′ is calculated using the equation (5) and is output to the voltage control unit 104. In the equation, T2 * is the set value of the secondary time constant.

[0024]

[Equation 5] In the torque current calculation unit 106, the input torque command T
The q-axis current command iq * is obtained from * and the estimated magnetic flux value φ ′ by using the equation (6). In the equation, L2 * is a set value of the secondary inductance, M * is a set value of the mutual inductance, and P is the number of poles of the induction motor 9.

[0025]

[Equation 6] The q-axis current command i output from the torque current calculation unit 106
A deviation of q * from the q-axis current detection value iq is obtained in the subtractor 107, and the deviation is subjected to PI processing in the torque current control unit 108, and the q-axis compensation voltage δvq is output to the voltage control unit 104. That is, in the subtractor 107 and the torque current control unit 108, the q-axis current command iq * and the q-axis current detection value iq are used to obtain the q-axis compensation voltage δvq, and the q-axis current command iq * is set to q. The axis current detection values iq are controlled so that they match. In the equation, Kpq and Kiq are control gains.

[0026]

[Equation 7] In the slip control unit 109, the q-axis current command iq *,
The slip frequency command ωs * is calculated from the estimated magnetic flux value φ ′ and the correction setting value R2 ′ of the secondary resistance using the equation (8).

[0027]

[Equation 8] The adder 110 adds the rotation speed ωr to the slip frequency command ωs * calculated by the slip control unit 109 to obtain the frequency command ω *, and outputs the frequency command ω * to the voltage control unit 104.

In the voltage controller 104, the d-axis current command id
*, Q-axis current command iq *, magnetic flux estimated value φ ′, d-axis compensation voltage δvd, q-axis compensation voltage δvq, rotation speed ωr, frequency command ω *, and correction setting value R2 ′ of the secondary resistance, (9 )
The d-axis voltage command vd * and the q-axis voltage command vq * are obtained from the expressions. In the equation, lσ * is a primary conversion leakage inductance setting value.

[0029]

[Equation 9] In the constant correction unit 111, the d-axis current command id *, the q-axis current command iq *, the estimated magnetic flux value φ ′, the d-axis compensation voltage δvd, q.
From the axis compensation voltage δvq and the slip frequency command ωs *,
Correction setting value R1 'of primary resistance, correction setting value R of secondary resistance
2 ′ and the mutual inductance correction setting value M ′ are calculated.

In FIG. 1, the correction setting value R of the primary resistance
Blocks to which 1 ', the correction setting value R2' of the secondary resistance, and the correction setting value M'of the mutual inductance are input are indicated by diagonal arrows, and the illustration of the input of each correction setting value is omitted. .

Next, the details of the constant correction unit 111 according to the characteristic part of the present invention will be described with reference to FIG. In the figure, the electromotive force calculation unit 201 takes in the d-axis compensation voltage δvd and the q-axis compensation voltage δvq, and uses the equation (10) to calculate the d-axis electromotive force e.
The d and q axis electromotive forces eq are calculated.

[0032]

[Equation 10] The magnetic flux error calculation unit 202 takes in the d-axis electromotive force ed and the q-axis electromotive force eq obtained by the electromotive force calculation unit 201,
The d-axis magnetic flux error δφd and the q-axis magnetic flux error δφq are calculated using the equation (11).

[0033]

[Equation 11] In FIG. 3, the block surrounded by the alternate long and short dash line 231 is the mutual inductance constant correction unit 231, and the block surrounded by the alternate long and short dashed line 232 is the primary resistance and secondary resistance constant correction unit 232. Further, in the figure, the coefficient unit 20
As shown in FIG. 4, the gain GH of 6,207,216,217 changes from “0” to “1” when the rotation speed ωr is equal to or lower than the set value ωr1, and when it exceeds ωr1 and is less than ωr2. It changes proportionally, and is set to "1" when ωr2 or more. Further, the gain GL of the coefficient unit 219 is set so as to be opposite to the gain GH, as shown in FIG. That is, the coefficient units 206, 207, 2
16, 217 and 219 act as a substantial switch that transmits a signal when the gain is "1" and blocks transmission of the signal when the gain is "0". However, when ωr1 is exceeded and ωr2 is less than, a signal is transmitted according to the gains of both coefficient units.

Next, the principle of the constant correction unit 111 will be described. (When the set value has no error) A case where there is no error between the motor constant of the induction motor 9 and the motor constant set in the control device will be described. Here, the steady state, that is, s = 0
Think about. The equation of state of an induction motor on a rotating coordinate axis that rotates at a frequency ω * is generally (1
It is represented by the equations (2), (13), (14) and (15). In these equations, vd is the d-axis voltage, and vq is q
Axial voltage, φd is d-axis magnetic flux, φq is q-axis magnetic flux, Rσ is primary conversion resistance, lσ is primary conversion leakage inductance, M
Is a mutual inductance, R2 is a secondary resistance, L2 is a secondary inductance, and T2 is a secondary time constant.

[0035]

[Equation 12]

[0036]

[Equation 13]

[0037]

[Equation 14]

[0038]

[Equation 15] Here, pay attention to the expressions (14) and (15). (3)
Substituting equations (5) and (8), d-axis magnetic flux φd
And q-axis magnetic flux φq are given by equations (16) and (17). The d-axis current id matches the d-axis current command id * due to the function of the exciting current control unit 103. Also, the q-axis current iq
Similarly, the torque current control unit 108 matches the q-axis current command iq *.

[0039]

[Equation 16]

[0040]

[Equation 17] On the other hand, the output torque T of the induction motor 9 is expressed by equation (18).

[0041]

[Equation 18] By substituting the equations (6), (16) and (17) into the equation (18), it can be seen that the torque command T * and the output torque T match. Therefore, when there is no error in the set value of the motor constant, the torque command T * and the output torque T match.

On the other hand, the power converter 8 causes the d-axis voltage command vd * and the d-axis voltage vd, and the q-axis voltage command vq * and the d-axis voltage v.
Since q is controlled so as to match, formulas (9) and (12)
Expressions (19) and (20) can be derived from the expressions and (13).

[0043]

[Formula 19]

[0044]

[Equation 20] By substituting the equations (19) and (20) into the equation (10), the equations (21) and (22) can be derived.

[0045]

[Equation 21]

[0046]

[Equation 22] Further, by substituting the equations (21) and (22) into the equation (11), the equations (23) and (24) can be derived.

[0047]

[Equation 23]

[0048]

[Equation 24] Therefore, when there is no error between the motor constant of the induction motor 9 and the set value of the motor constant set in the control device, and the equations (16) and (17) hold, the d-axis magnetic flux error δφd.
And the q-axis magnetic flux error δφq becomes 0, and the constant correction unit 111
The mutual inductance, the primary resistance, and the secondary resistance correction set values M ′, R1 ′, and R2 ′ output from the output signals coincide with the set values M *, R1 *, and R2 *, respectively. (When an error occurs in the set value) Here, a case where an error occurs in the set value of the motor constant will be considered. Note that here, lσ and M / L
Regarding No. 2, it is assumed that there is no error in the motor constant of the induction motor 9 and the set value of the motor constant set in the control device, and there is an error only in the mutual inductance, the primary resistance, and the secondary resistance, and the primary resistance and It is assumed that the error rate of the secondary resistance is equal.

-When the rotation speed is higher than a set value- Consider the case where the rotation speed ωr is higher than ωr2, for example. Mutual inductance setting error ΔM, primary resistance setting error Δ
The variation Δφd of the d-axis magnetic flux with respect to the setting error ΔR2 of R1 and the secondary resistance is given by the equation (25) from the equation (14).

[0050]

[Equation 25] From equation (25), it can be seen that the d-axis magnetic flux fluctuates due to the mutual inductance setting error ΔM. On the other hand, when the d-axis magnetic flux fluctuates, it can be detected by the d-axis magnetic flux error δφd as shown in the equation (23). Furthermore, based on the d-axis magnetic flux error δφd, the mutual inductance constant correction unit 231 in FIG. 3 corrects the mutual inductance correction setting value M ′. That is, the correction setting value M ′ of the mutual inductance changes so that the d-axis magnetic flux error δφd becomes zero.

Here, when the d-axis magnetic flux error δφd becomes 0, the correction setting value M ′ of the mutual inductance agrees with the mutual inductance M of the induction motor 9 from the equation (25), and the setting error of the mutual inductance is reduced. Can be compensated.

Therefore, the mutual inductance constant correcting unit 231 of FIG. 3 basically corrects the error between the set value M * of the mutual inductance and the actual value by reducing the d-axis magnetic flux error δφd to zero. Is configured. First, in the coefficient unit 203, the d-axis magnetic flux error δφd is multiplied by the constant Kpfd to obtain the first correction amount. This first correction amount is transmitted to the coefficient unit 210 via the adder 205, the coefficient unit 206, and the adder 208, and the coefficient unit 2
Mutual inductance set value M * set to 10
Is multiplied by. As a result, the set value M * of mutual inductance is corrected, and the corrected set value M ′ of mutual inductance is output from the coefficient unit 210.

In the coefficient unit 204, the d-axis magnetic flux error δφd is multiplied by the constant Kifd to obtain the second correction amount. The second correction amount is added to the first correction amount via the coefficient unit 206, the integrator 209, and the adder 208. That is, the system of the first correction amount and the system of the second correction amount constitute a correction system by PI processing. As a result, the mutual inductance correction set value M ′ is set so that the d-axis magnetic flux error δφd caused by the mutual inductance setting error becomes 0.
To be matched.

By the way, the fluctuation of the q-axis magnetic flux φq is caused by the third term on the right side of the equation (14), and the fluctuation of the d-axis magnetic flux φd is caused by the second term on the right side of the equation (15). It causes fluctuations in the magnetic flux φq. That is, (1
The d-axis magnetic flux and the q-axis magnetic flux interfere with each other due to the third term on the right side of the equation (4) and the second term on the right side of the equation (15). For this reason,
In order to stably correct the set values of the mutual inductance and the secondary resistance, it is necessary to remove the influence of this interference.
Therefore, based on the d-axis magnetic flux error δφd, the influence of the second term of the equation (15) is made non-interfering by adjusting the correction setting estimation R2 ′ of the secondary resistance via the coefficient multiplier 212. That is, in the coefficient unit 211 of FIG. 3, the q-axis magnetic flux error δφq
The slip frequency command ωs * is multiplied by the setting value T2 * of the secondary time constant to obtain the third correction amount. This third correction amount is added to the first correction amount in the adder 205, so that interference is suppressed.

On the other hand, the mutual inductance setting error Δ
M, primary resistance setting error ΔR1, secondary resistance setting error Δ
The fluctuation Δφq of the q-axis magnetic flux with respect to R2 is given by equation (26) from equation (15).

[0056]

[Equation 26] Since the influence of the error of the mutual inductance is compensated as described above, the fluctuation Δφq of the q-axis magnetic flux is given by the equation (27).

[0057]

[Equation 27] Of the error of the secondary time constant T2, the error of the secondary inductance L2 is offset by the fluctuation of the d-axis magnetic flux φd. Therefore, the setting error of the secondary resistance is the main cause of the fluctuation Δφq of the q-axis magnetic flux. On the other hand, when the q-axis magnetic flux fluctuates, it can be detected by the q-axis magnetic flux error δφq as shown in Expression (24). Furthermore, based on the q-axis magnetic flux error δφq, the primary resistance and secondary resistance constant correction unit 232 of FIG. 3 adjusts the correction setting value R2 ′ of the secondary resistance, whereby the q-axis magnetic flux error δφq becomes zero. Correction value R of secondary resistance
2'changes.

When the q-axis magnetic flux error δφq becomes 0, (2
From the equation (7), the correction setting value R2 ′ of the secondary resistance is the induction motor 9
Since it coincides with the secondary resistance R2, it is possible to compensate the setting error of the secondary resistance R2. Further, since the main cause of the setting error of the secondary resistance is temperature change, the setting error of the primary resistance, which also changes with temperature, can be corrected similarly to the secondary resistance.

Therefore, as shown in FIG. 3, the secondary resistance constant correcting unit 232 basically reduces the q-axis magnetic flux error δφq to 0, thereby setting the secondary resistance set value R2 * and the actual value. The error of is corrected. First, the coefficient unit 214 multiplies the q-axis magnetic flux error δφq by a constant Kpfq to obtain a fourth correction amount. The fourth correction amount is transmitted to the coefficient unit 224 via the adder 215, the coefficient unit 217, and the adder 222, and is multiplied by the set value R2 * of the secondary resistance set in the coefficient unit 224. . As a result, the set value R2 * of the secondary resistance is corrected, and the correction set value R2 ′ of the secondary resistance is output from the coefficient unit 224.

Further, in the coefficient unit 213, the q-axis magnetic flux error δφq is multiplied by the constant Kifq to obtain the fifth correction amount. The fifth correction amount is added to the fourth correction amount via the coefficient unit 216, the adder 220, the integrator 221, and the adder 222. That is, the system of the fourth correction amount and the system of the fifth correction amount constitute a correction system by PI processing. As a result, the correction setting value R2 ′ matches the actual secondary resistance R2 so that the q-axis magnetic flux error δφq caused by the setting error of the secondary resistance becomes zero.

By the way, as described above, the variation of the q-axis magnetic flux φq is caused by the third term on the right side of the equation (14), and the variation of the d-axis magnetic flux φd is caused by the second term on the right side of the equation (15). Changes the q-axis magnetic flux φq. That is, the d-axis magnetic flux and the q-axis magnetic flux interfere with each other due to the third term on the right side of the equation (14) and the second term on the right side of the equation (15). Therefore, in order to stably correct the set values of the mutual inductance and the secondary resistance, it is necessary to remove the influence of this interference.

Therefore, the d-axis magnetic flux error δφd is subtracted from the fourth correction amount in the subtractor 215 as the sixth correction amount, thereby suppressing the interference.

-When the rotation speed ωr is smaller than ωr1-
When the rotation speed ωr is low, the d-axis electromotive force ed and the q-axis electromotive force eq obtained by the equation (10) are low. Therefore, when the rotation speed ωr is small, the influence of the error in the second term on the right side of the equation (10) caused by the setting error of the primary resistance and the secondary resistance becomes large. As a result, the d-axis electromotive force ed or q
When the polarity of the axial electromotive force eq is reversed, the change in the correction setting value is also reversed, so that the correction setting value diverges. Therefore, the correction based on the above principle is stopped by reducing the gain GH in the region where the rotation speed ωr is small.

From the equations (10) and (20), the q-axis electromotive force e
q is given by equation (28). However, ΔRσ is equation (29).

[0065]

[Equation 28]

[0066]

[Equation 29] Here, the difference between the results of equations (28) and (22) is that
This is because the effect of resistance error is taken into consideration. When there is no resistance error or when the rotation speed ωr is large and the influence of the resistance error is small, the formula (22) can be used. But,
When the rotation speed ωr becomes small and the influence of the resistance error is large, the expression (28) is obtained. Therefore, when the rotation speed ωr is small, the correction setting value R1 ′ of the primary resistance and the correction setting value R of the secondary resistance are set so that the calculated q-axis electromotive force eq becomes zero.
Adjust 2 '. That is, the gain GL of the coefficient unit 219
Is set to “1” and the coefficient unit 21 is calculated based on the q-axis electromotive force eq.
8, through the coefficient unit 219, the adder 220, the integrator 221, the adder 222, the coefficient unit 223 or the coefficient unit 224, the correction setting value R1 ′ of the primary resistance and the correction setting value R of the secondary resistance
Adjust 2 '. However, since the equation (28) is satisfied only in the region where the rotation speed ωr is low, it is necessary to reduce the gain GL in the region where the rotation speed ωr is high.

Therefore, in the embodiment shown in FIG. 3, in the coefficient unit 218, the q-axis electromotive force eq is multiplied by the constant Kir to obtain the seventh correction amount. This seventh correction amount is
The coefficient 219 is multiplied by the gain GL, and the adder 2
It is replaced with the fifth correction amount from 162. That is, when the gain GL of the coefficient unit 219 is close to “1”, the gain GH of the coefficient unit 216 is close to “0”, and therefore the rotation speed ωr
Accordingly, either the fifth or seventh correction amount of the coefficient unit 216 or the coefficient unit 219 is input to the integrator 2212. In this way, the correction amount output from the adder 222 is set in the coefficient unit 224 by the set value R of the secondary resistance.
2 * is multiplied to obtain the correction set value R2 '. Since the primary resistance changes in the same manner as the secondary resistance, the correction amount output from the adder 222 is multiplied by the set value R1 * of the primary resistance set in the coefficient unit 223 to obtain the correction set value R1 ′. Desired.

Next, the manner in which the setting errors of the mutual inductance, the primary resistance and the secondary resistance are corrected will be specifically described. First, consider the case where the rotation speed ωr is high. When the set value M * of the mutual inductance is large, the exciting current calculator 101 calculates the d-axis current command i based on the equation (3).
Since d * becomes smaller and the d-axis current id matches id * due to the function of the exciting current controller, the d-axis current id also becomes smaller. As a result, in the induction motor 9, the absolute value of the first term on the right side of the expression (14) becomes small, so that the d-axis magnetic flux φd becomes small. Further, when the d-axis magnetic flux φd becomes smaller, the third term on the right side of the equation (13) becomes smaller and the q-axis current iq increases. As a result, the q-axis current iq input to the subtractor 107 increases, and the q-axis compensation voltage δvq output from the torque current control unit 108 decreases.

As a result, in the constant correction unit 111, (1
The q-axis electromotive force eq calculated based on the equation (0) decreases, and the d-axis magnetic flux error δφd calculated based on the equation (11).
Is reduced. When the d-axis magnetic flux error δφd decreases, the coefficient unit 2
03 to adder 208 and coefficient unit 204 to adder 20
8. Further, the correction setting value M ′ of the mutual inductance is reduced via the coefficient unit 210 and approaches the true value M.

On the other hand, as the d-axis magnetic flux φd decreases, the second term on the right side of the equation (15) decreases inside the induction motor 9, so that the q-axis magnetic flux φq increases and interference occurs. How to suppress this interference will be described. When the d-axis magnetic flux φd is reduced as described above, the d-axis magnetic flux error δφd is reduced.
As a result, the correction setting value R2 ′ of the secondary resistance increases due to the path from the coefficient multiplier 212 to the coefficient multiplier 224. for that reason,
The slip frequency command ωs * calculated by the slip frequency control unit 109 based on the equation (8) increases. As a result, (1
The second term on the right side of the expression (5) cancels out the decrease in the d-axis magnetic flux φd by the increase in the slip frequency ωs and suppresses the variation in the q-axis magnetic flux φq, so that interference can be suppressed.

Next, when the correction setting value R2 'of the secondary resistance is large, the slip frequency command ωs * calculated by the slip control unit 109 based on the equation (8) increases, and the frequency command ω passes through the adder 110. * Increases. As a result, in the induction motor 9, the second term on the right side of the expression (15) becomes large, and the q-axis magnetic flux φq becomes small. Further, the absolute value of the fourth term on the right side of the expression (12) becomes small, and the d-axis current id decreases. As a result, the d-axis current id input to the subtractor 102 decreases, and the d-axis compensation voltage δ output from the exciting current control unit 103.
vd increases. Therefore, in the constant correction unit 111,
The d-axis electromotive force ed calculated based on the equation (10) increases, and the q-axis magnetic flux error δφq calculated based on the equation (11) decreases. As a result, when the q-axis magnetic flux error δφq decreases, the coefficient unit 213 to the adder 222 and the coefficient unit 21
The correction setting value R2 ′ of the secondary resistance decreases from 4 through the adder 222 and the coefficient unit 224, and approaches the true value R2.

On the other hand, as the q-axis magnetic flux φq decreases, the absolute value of the third term on the right side of the expression (14) decreases inside the induction motor 9, so that the d-axis magnetic flux φd decreases and interference occurs. How to suppress this interference will be described. When the q-axis magnetic flux φq decreases as described above, the q-axis magnetic flux error δφq decreases. As a result, the correction setting value M ′ of the mutual inductance decreases due to the path from the coefficient unit 211 to the coefficient unit 210. When the correction setting value M ′ of the mutual inductance decreases, the d-axis current command id * calculated by the exciting current calculator 101 based on the equation (3) increases, and the d-axis current id is id by the function of the exciting current controller. Since it matches with *, the d-axis current id also increases. As a result, the absolute value of the first term on the right side of the equation (14) increases, so that the q-axis magnetic flux φq decreases (1
Since the decrease in the absolute value of the third term on the right side of the equation 4) is offset and the fluctuation of the d-axis magnetic flux φd is suppressed, the interference can be suppressed.

Next, consider the case where the rotation speed is low. In this case, since the gains GH of the coefficient units 206 and 207 approach "0", the mutual inductance set value M * is not corrected. Therefore, the case where the set value R2 * of the secondary resistance is larger than the actual value will be described. Rotational speed ωr
When q is small, the q-axis magnetic flux φq decreases, but (12)
Since the rotation speed ωr included in the fourth term on the right side of the equation is small, q
The change in the axial current iq is minute. On the other hand, since the absolute value of the second term on the right side of the expression (10) increases, the electromotive force eq decreases. As a result, the correction setting value R2 ′ of the secondary resistance decreases from the coefficient unit 218 through the coefficient unit 224 and approaches the true value R2.

In the above description, the case where the set value such as the mutual inductance is large has been described, but when the set value is small, the change is only reversed and the set value approaches the true value in the same manner.

Further, since the change in the secondary resistance is mainly caused by the temperature change, when the secondary resistance increases, it means that the temperature rises. At this time, the primary resistance also increases at the same time. There is. Therefore, the output of the adder 222 increases,
When the correction setting value R2 ′ of the secondary resistance increases, the coefficient unit 2
The correction setting value of the primary resistance which is the output of 23 is also increased.

As described above, according to the present embodiment, the secondary resistance and the mutual inductance can be simultaneously corrected and set, and the secondary resistance can be stably estimated even in the region where the rotation speed is low. Since the primary resistance is estimated based on the amount proportional to the secondary resistance, highly accurate torque control becomes possible.

[0077]

As described above, according to the present invention, it is possible to simultaneously compensate for the setting error of the secondary resistance and the mutual inductance in the control device for the induction motor.

Further, the setting error of the secondary resistance can be stably compensated even in the region where the rotation speed is low.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of a frequency voltage control unit that is a main part of a control device for an induction motor according to the present invention.

FIG. 2 is an overall configuration diagram of an embodiment of a control device in which the present invention is applied to an induction motor for driving a vehicle.

3 is a diagram showing a detailed configuration of a constant correction unit 111 in FIG.

FIG. 4 is a diagram illustrating a relationship between a rotation speed and gains GH and GL.

[Explanation of symbols]

9 induction motor 10 Current detector 13 Current coordinate converter 14 Frequency voltage controller 101 Exciting current calculator 102 Subtractor 103 Exciting current controller 107 Subtractor 108 Torque current control unit 109 Slip controller 111 Constant correction unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor, Yuto Suzuki             1070 Ichimo, Hitachinaka City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Transportation Systems Division Mito Transportation             System headquarters (72) Inventor Tetsuro Kojima             1070 Ichimo, Hitachinaka City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Transportation Systems Division Mito Transportation             System headquarters F-term (reference) 5H576 CC01 DD04 EE01 FF07 GG04                       HB01 HB02 JJ01 JJ05 JJ25                       LL01 LL22 LL29 LL30 LL40

Claims (8)

[Claims] 1. A motor including a rotating coordinate system converting means for detecting a current flowing through an induction motor and converting it into an exciting current detection value and a torque current detection value in a rotating coordinate system, and a secondary resistance and a mutual inductance of the induction motor. Frequency voltage control means for controlling the frequency and voltage of the induction motor based on a set value of a constant, the frequency voltage control means is applied to the induction motor based on the difference between the excitation current command and the excitation current detection value. Excitation current control means for controlling the voltage to be applied, torque current control means for controlling the voltage applied to the induction motor based on the difference between the torque current command and the detected torque current value, the excitation current control means and the torque current. A control device for an induction motor, comprising: a motor constant correction means for correcting the set values of the secondary resistance and the mutual inductance based on the output of the control means. Place 2. The motor constant correcting means estimates a d-axis magnetic flux error from outputs of the exciting current control means and the torque current control means, and reduces the mutual inductance of the mutual inductance so as to reduce the d-axis magnetic flux error. Correcting the set value, estimating the q-axis magnetic flux error from the outputs of the exciting current control means and the torque current control means, and correcting the set value of the secondary resistance so as to reduce the q-axis magnetic flux error. The control device for the induction motor according to claim 1. 3. The motor constant correction means corrects the set values of the secondary resistance and the mutual inductance only when the rotation speed of the induction motor is higher than the set values. 2. The control device for the induction motor according to 2. 4. A rotating coordinate system converting means for detecting a current flowing through the induction motor and converting it into an exciting current detection value and a torque current detection value of the rotating coordinate system, and setting of a motor constant including a secondary resistance of the induction motor. Frequency voltage control means for controlling the frequency and voltage of the induction motor based on a value, the frequency voltage control means, the voltage to be applied to the induction motor based on the difference between the excitation current command and the detection value of the excitation current. Excitation current control means for controlling, torque current control means for controlling the voltage applied to the induction motor based on the difference between the torque current command and the detected torque current value, and the rotation speed of the induction motor is smaller than a set value And a motor constant correction means for correcting the set value of the secondary resistance based on the output of the torque current control means. 5. A motor including a rotating coordinate system conversion means for detecting a current flowing through the induction motor and converting it into an exciting current detection value and a torque current detection value of the rotating coordinate system, and a secondary resistance and a mutual inductance of the induction motor. Frequency voltage control means for controlling the frequency and voltage of the induction motor based on a set value of a constant, the frequency voltage control means is applied to the induction motor based on the difference between the excitation current command and the excitation current detection value. Excitation current control means for controlling the voltage to be applied, torque current control means for controlling the voltage applied to the induction motor based on the difference between the torque current command and the detected torque current value, the excitation current control means and the torque current. The d-axis magnetic flux error is estimated from the output of the control means, and the set value of the mutual inductance is corrected so as to reduce the d-axis magnetic flux error. , The q-axis electromotive force of the induction motor is obtained from the output of the torque current control means, and the set value of the mutual inductance is calculated by multiplying the q-axis electromotive force by the slip frequency command and the set value of the secondary time constant. Furthermore, the q-axis magnetic flux error is estimated from the outputs of the excitation current control means and the torque current control means, and the set value of the secondary resistance is corrected so as to reduce the q-axis magnetic flux error. A control device for an induction motor, comprising: a motor constant correction means for further correcting the set value of the secondary resistance due to a d-axis magnetic flux error. 6. The motor constant correcting means corrects the set values of the secondary resistance and the mutual inductance only when the rotation speed of the induction motor is higher than the set values. Induction motor control device described. 7. The control device for an induction motor according to claim 1, wherein the set value of the primary resistance of the induction motor is corrected based on the correction amount of the secondary resistance. 8. A rotating coordinate system conversion means for detecting a current flowing through the induction motor and converting it into an exciting current detection value and a torque current detection value in a rotating coordinate system, and a motor including a secondary resistance and a mutual inductance of the induction motor. Frequency voltage control means for controlling the frequency and voltage of the induction motor based on a set value of a constant, the frequency voltage control means is applied to the induction motor based on the difference between the excitation current command and the excitation current detection value. Excitation current control means for controlling the voltage, torque current control means for controlling the voltage applied to the induction motor based on the difference between the torque current command and the detected torque current value, and the set value of the motor constant are corrected. A motor constant correction means, wherein the motor constant correction means is configured such that, when the rotation speed is equal to or higher than a set value, the excitation current control means and the torque current control hand. The d-axis magnetic flux error is estimated from the stage output, the mutual inductance set value is corrected so as to reduce the d-axis magnetic flux error, and the q-axis of the induction motor is calculated from the output of the torque current control means. A mutual inductance correction unit that calculates an electromotive force and further corrects the set value of the mutual inductance by a value obtained by multiplying the q-axis electromotive force by the slip frequency command and the set value of the secondary time constant; At this time, the q-axis magnetic flux error is estimated from the outputs of the exciting current control means and the torque current control means, and the set value of the secondary resistance is corrected so as to reduce the q-axis magnetic flux error. The magnetic flux error of the shaft is multiplied by the slip frequency command and the set value of the secondary time constant to further correct the set value of the secondary resistance. Control device for a secondary resistance correction part and comprising a induction motor for correcting the secondary resistance set value based on the output of the current control means.