JP2018014809A - Controller of induction motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stable torque control by reducing error of secondary time constant estimate, respectively, of powering operation and regenerative operation, in the controller of induction motor.SOLUTION: A powering/regeneration discrimination flag Flag, that is 0 when the product of torque command value Tref and number of revolution detection value ωdet is equal to or less than 0 otherwise 1, is calculated. A secondary time constant estimate τrcest is calculated based on the γ-axis current detection value Iγdet, the δ-axis current detection value Iδdet, the γ-axis current error eiγ of the γ-axis current detection value Iγdet and the γ-axis current estimate Iγest, the δ-axis current error eiδ of the δ-axis current detection value Iδdet and the δ-axis current estimate Iδest, and the powering/regeneration discrimination flag Flag.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for compensating a secondary resistance value during induction motor vector control, and more particularly to a method for compensating a secondary resistance value during four-quadrant operation of power regeneration.

  In the vector control of the induction motor, the primary resistance Rs, the secondary resistance Rr, the primary leakage inductance ls, the secondary leakage inductance lr, and the mutual resistance M, which are the actual parameters of the motor, are the primary resistance setting value Rsc and the secondary resistance. If there is an error in the set value Rrc, the primary leakage inductance setting value lsc, the secondary leakage inductance setting value lrc, and the mutual inductance setting value Mc, the vector control performance is deteriorated.

  The operation of the induction motor in a state in which the vector control performance is deteriorated is not preferable because a torque error occurs in an application for performing torque control. In particular, fluctuations in the secondary resistance Rr are undesirable because they are directly linked to vector axis misalignment (axis misalignment) when slip frequency vector control is performed. However, since actual parameters such as the secondary resistance Rr vary depending on the operating temperature or the like, measurement is difficult.

  Thus, many secondary resistance compensation methods during operation have been proposed. However, Non-Patent Document 1 shows that the secondary resistance compensation value becomes unstable in the regenerative operation when a current error that is an error between the current prediction value and the current detection value is used as the compensation method. In actual operation of the induction motor, there is a case where it is operated in four quadrants of power running regeneration, and therefore a method of performing secondary resistance compensation stably even in the regeneration region is required.

  The following prior art documents are techniques aimed at realizing stable motor drive even during regeneration.

(Patent Document 1)
[Problem] Stable motor drive can be realized even during regeneration by suppressing control deterioration due to temperature fluctuations and constant setting errors without changing the constant used in the state estimator and taking into account the vector state in the regeneration state of the motor. Like that.
[Solution] The voltage command is corrected from the state of the current error, the rotor angular velocity and the current command. Whether it is power running or regeneration is determined from the rotor angular velocity and current command (corresponding to torque current command), and in the case of regeneration, the inner product value used for estimation is multiplied by -1. Compensating the inverter voltage command based on this value enables stable compensation even if an error occurs in the primary resistance value. Further, the threshold value for power regeneration is determined from the rotational speed and torque and slip, and in the case of regeneration, -1 is multiplied.

(Patent Document 2)
[Problem] To realize robust control against motor parameter setting error.
[Solution] Based on the d-axis current error, proportional compensation is performed in the direction of the primary current vector or the direction of the detected primary current vector. Although the setting error and the d-axis current error vary depending on the state of the load torque, it is difficult to detect the load torque. Therefore, only the proportional term using the d-axis current error is compensated.

  Therefore, the voltage correction is not a complete correction, and the error amount between the secondary magnetic flux axis and the d axis is also corrected separately using the d axis current error.

WO2009 / 041157 JP 2009-195106 A

“Proposal and Stability of Induction Motor Parameter Adaptive Secondary Flux Observer”, Kubota and Matsuse, IEEJ Transactions, Vol. 111, No3, p188 (1991) “A Study on Stability of Vector Control Induction Motor System Using Adaptive Secondary Flux Observer” Sugimoto and Ding, IEEJ Transactions, Vol. 119, No10, p1212 (1999)

  Both of the above-described prior arts are systems for compensating for deviations in induction motor parameters due to setting errors and temperature changes when performing four-quadrant operation for power regeneration with an induction motor. In particular, by compensating the primary resistance, a desired control accuracy can be obtained even in a low speed region.

  However, when general slip frequency type vector control is performed, the slip frequency is estimated from the γδ axis current detection value and the secondary time constant τr (= Lr / Rr) of the induction motor. However, since it is difficult to measure the actual value (Rr) of the secondary resistance, the set secondary time constant τrc (= Lrc / Rrc) is almost always used in practice.

  When a temperature change or the like of the induction motor occurs during operation, the secondary resistance Rr varies in the same manner as the primary resistance Rs. In such a case, it is predicted that the set secondary time constant τrc has an error from the true value of the secondary time constant τr and the desired control performance cannot be obtained.

  The secondary self-inductance Lr in the text is obtained by leakage inductance lr + mutual inductance M. Similarly, the primary self-inductance Ls is obtained by Ls = ls + M.

  As described above, in the control apparatus for an induction motor, it is a problem to perform stable torque control by reducing the error of the secondary time constant estimation value for each of the power running operation and the regenerative operation.

  The present invention has been devised in view of the above-described conventional problems, and one aspect thereof is the deviation between the γ-axis current command value and the γ-axis current detection value, the δ-axis current command value, and the δ-axis current detection value. A current control unit that outputs a γ-axis voltage command value and a δ-axis voltage command value, and a γ-axis voltage command value and a δ-axis voltage command value that are converted into a three-phase voltage command value. A one-coordinate conversion unit, an inverter that outputs a voltage corresponding to the three-phase voltage command value, an induction motor that is driven by the voltage output from the inverter, and the three-phase inverter output current that is the γ-axis current detection value, Γ which is a difference between the second coordinate conversion unit for converting into the δ-axis current detection value, the γ-axis current detection value, the δ-axis current detection value, the γ-axis current estimation value, and the γ-axis current detection value. Shaft current error, δ-axis current error that is the difference between the estimated value of δ-axis current and the detected value of δ-axis current, and torque Secondary time constant estimation that calculates a secondary time constant estimated value based on a power running regeneration determination flag that is 0 when the product of the instruction value and the rotational speed detector is 0 or less, and 1 when it is greater than 0 And a slip calculation / electrical angle calculation unit for calculating a slip angular frequency and an electrical angle based on the estimated second-order time constant value.

  Moreover, as one aspect thereof, the second-order time constant estimation unit calculates a first-order time constant estimated value and the second-order time constant estimated value according to the following expressions (9) to (12): .

  As one aspect thereof, the second-order time constant estimation unit calculates a γ-axis current error and a δ-axis current error by the following equations (5) to (6).

  As another aspect, based on the deviation between the γ-axis current command value and the detected γ-axis current value, and the difference between the δ-axis current command value and the detected δ-axis current value, the γ-axis voltage command value and the δ-axis voltage command A current control unit that outputs a value, a first coordinate conversion unit that converts the γ-axis voltage command value and the δ-axis voltage command value into a three-phase voltage command value, and a voltage corresponding to the three-phase voltage command value An inverter that outputs a voltage output from the inverter, a second coordinate conversion unit that converts the three-phase inverter output current into the γ-axis current detection value and the δ-axis current detection value, The first stable range, the second stable range, and the third stable range with respect to the detected rotational speed value and the torque command value are stored in advance, and the detected rotational speed value and the torque command value are within the first stable range. If there is a switch flag, turn it off if it is outside the first stability range and within the second stability range If the flag is out of the first and second stable ranges and within the third stable range, the time constant estimation formula switching discriminating unit that outputs the switching flag with the switching flag set to 3, and when the switching flag is 1, Formula (14): When the switching flag is 2, the formula (15) is selected. When the switching flag is 3, the formula (16) is selected, and the γ-axis current detection value and the δ are calculated by the selected calculation formula. An axis current detection value, a γ-axis current error that is the difference between the estimated γ-axis current value and the detected γ-axis current value, and a δ-axis current error that is the difference between the estimated δ-axis current value and the detected δ-axis current value A second-order time constant estimation unit that calculates a second-order time constant estimation value, and a slip calculation / electric-angle calculation unit that calculates an electrical angle based on the second-order time constant estimation value. It is characterized by.

  Also, as one aspect thereof, based on the deviation between the γ-axis current command value and the detected γ-axis current value, and the difference between the δ-axis current command value and the detected δ-axis current value, the γ-axis voltage command value and the δ-axis voltage command A current control unit that outputs a value, a first coordinate conversion unit that converts the γ-axis voltage command value and the δ-axis voltage command value into a three-phase voltage command value, and a voltage corresponding to the three-phase voltage command value An inverter that outputs a voltage output from the inverter, a second coordinate conversion unit that converts the three-phase inverter output current into the γ-axis current detection value and the δ-axis current detection value, The first stable range, the second stable range, and the third stable range with respect to the slip angular frequency and the torque command value obtained in advance are stored, and if the slip angular frequency and the torque command value are within the first stable range. Set the switching flag to 1, outside the first stable range and within the second stable range If the switching flag is 2, out of the first and second stable ranges and within the third stable range, the switching flag is set to 3, and the time constant estimation type switching discriminating unit for outputting the switching flag, and the switching flag is 1 (14), (15) if the switching flag is 2, and (16) if the switching flag is 3, the γ-axis current detection value and The δ-axis current detection value, the γ-axis current error that is the difference between the γ-axis current estimation value and the γ-axis current detection value, and the δ that is the difference between the δ-axis current estimation value and the δ-axis current detection value A second-order time constant estimator that calculates a second-order time constant estimated value based on an axial current error; and a slip operation / electric-angle calculator that calculates an electrical angle based on the second-order time constant estimated value. It is characterized by having.

  As one aspect thereof, the second-order time constant estimation unit calculates a γ-axis current error and a δ-axis current error by the following equations (5) to (6).

  According to the present invention, in the control apparatus for an induction motor, it is possible to perform stable torque control by reducing the error of the estimated second-order time constant for each of the power running operation and the regenerative operation.

FIG. 2 is a block diagram illustrating a control device for the induction motor according to the first embodiment. FIG. 3 is a block diagram illustrating a second-order time constant estimation unit according to the first embodiment. 5 is a flowchart illustrating control processing according to the first embodiment. The figure which shows the torque waveform in Embodiment 1. FIG. The block diagram which shows the control apparatus of the induction motor in Embodiment 2. FIG. FIG. 5 is a block diagram showing a parameter estimator in the second embodiment. The figure which shows the stable range at the time of estimating by (8) Formula. The figure which shows the stable range at the time of estimating by (9) Formula. The figure which shows the stable range at the time of estimating by (10) Formula. The figure which shows the simulation result in the prior art and Embodiment 2. FIG.

  The present invention is a system capable of stably operating the four-quadrant operation of power regeneration by reducing the error between the set secondary time constant τrc and the true value of the secondary time constant τr. Although the secondary resistance compensation value at the time of power running can be obtained stably, there is a problem that the secondary resistance compensation value becomes unstable at the time of regeneration. Therefore, the method of obtaining the secondary resistance compensation value at the time of regeneration is switched. The secondary resistance compensation at the time of regeneration is configured to reflect the compensation value at the time of power running, so that the same effect as at the time of power running can be obtained even at the time of regeneration. Hereinafter, Embodiments 1 to 3 of the present invention will be described with reference to FIGS.

[Embodiment 1]
The induction motor control apparatus according to Embodiment 1 will be described. FIG. 1 is a block diagram showing a control device for an induction motor according to the first embodiment. First, in the current command calculation unit 1, based on the γ-axis magnetic flux command value φγref and the torque command value Tref, for example, the following γ-axis current command value Iγref and δ-axis current command value by the following formulas (1) and (2): Iδref is calculated.

  The subtractor 2 calculates a γ-axis current deviation that is a deviation between the γ-axis current command value Iγref and the γ-axis current detection value Iγdet. The γ-axis current deviation is output to the current control unit 4. Similarly, the subtractor 3 calculates a δ-axis current deviation which is a deviation between the δ-axis current command value Iδref and the δ-axis current detection value Iδdet. The δ-axis current deviation is output to the current control unit 4.

  In the current control unit 4, based on the γ-axis current deviation and the δ-axis current deviation, for example, the γ-axis current deviation and the δ-axis current deviation become zero by the PI control. Vδref is calculated. The coordinate conversion unit 5 uses the γ-axis voltage command value Vγref and the δ-axis voltage command value Vδref output from the current control unit 4 based on the electrical angle reference phase θe, the u-phase voltage command value vrefef, v-phase voltage command value vvref and w-phase voltage command value vwref are converted. A power converter such as the PWM inverter 6 outputs the voltage corresponding to the three-phase voltage command values vrefef, vvref, vwref to the induction motor IM to operate the induction motor IM.

  The three-phase current detection values iudet, ivdet, iwdet are converted into a γ-axis current detection value Iγdet and a δ-axis current detection value Iδdet in the coordinate conversion unit 7.

  In the first embodiment, the coordinate conversion units 5 and 7 use the rotation matrix and the three-phase two-phase conversion matrix of the following equations (3) and (4).

  The secondary time constant estimation unit 8 includes a γ-axis voltage command value Vγref, a δ-axis voltage command value Vδref, a γ-axis current detection value Iγdet, a δ-axis current detection value Iδdet, a rotation speed detection value ωdet, an electrical angle (electrical angle calculation). Value) ωe and torque command value Tref are input.

  Details of the secondary time constant estimation unit 8 are shown in FIG. In the secondary time constant estimation unit 8, a γ-axis voltage command value Vγref, a δ-axis voltage command value Vδref, an electrical angle ωe, a rotation speed detection value ωdet, a γ-axis current detection value Iγdet, a δ-axis current detection value Iδdet, which will be described later. The secondary time constant estimated value τrcest and the primary time constant estimated value τsest (Lsc / Rsc), which are the outputs of the time constant estimating unit 8d, are input to the current observer 8a. The current observer 8a calculates the estimated γ-axis current value Iγest and the estimated δ-axis current value Iδest by the following equation (5).

  In the current error calculation unit 8b, based on the γ-axis current estimated value Iγest, the δ-axis current estimated value Iδest, and the γ-axis current detected value Iγdet and the δ-axis current detected value Iδdet, the following equation (6) is used to calculate the γ-axis The difference between the detected current value Iγdet and the estimated γ-axis current value Iγest and the difference between the detected δ-axis current value Iδdet and the estimated δ-axis current value Iδest are calculated to calculate the γ-axis current error eiγ and the δ-axis current error eiδ. To do.

  Further, the power running regeneration determination unit 8c calculates a power running regeneration determination flag Flag by the following equations (7) and (8) based on the torque command value Tref and the rotation speed detection value ωdet.

  Based on the γ-axis current error eiγ, the δ-axis current error eiδ, the power running regeneration determination flag Flag, the γ-axis current detection value Iγdet, and the δ-axis current detection value Iδdet, the time constant estimation unit 8d The first-order time constant estimated value τsest and the second-order time constant estimated value τrcest are calculated from the equation (12).

σ = 1−M2 / (LsLr) Mc = mutual inductance Ls = primary self-inductance Lr: secondary self-inductance As shown in FIG. 1, the secondary time constant estimated value τrcest and γ estimated by the secondary time constant estimator 8 The shaft current command value Iγref, the δ-axis current command value Iδref, and the rotation speed detection value ωdet are output to the slip calculation / electrical angle calculation unit 9, and in the slip calculation / electrical angle calculation unit 9, the electrical angle ωe is obtained by the equation (13). Ask for.

  Since the equation (13) is a general equation that can be derived by vector control in which the induction motor IM sets the δ-axis magnetic flux command value φδref = 0, description thereof is omitted.

  In the integrator 10, the electrical angle reference phase θe is obtained from the electrical angle ωe obtained by the equation (13), and the electrical angle reference phase θe is used as a reference axis at the time of coordinate conversion.

  In the first embodiment, when there is an error between the actual secondary resistance Rr and the secondary resistance set value Rrc before the operation or due to a temperature change during the operation, there is an error between the actual secondary resistance Rr and the secondary resistance set value Rrc. In this case, the slip angular frequency ωslip is estimated by using the second-order time constant estimated value τrcest that is sequentially estimated during operation, and the desired control performance can be obtained even under the condition that the shaft misalignment occurs. Can do.

  In addition, since the calculation formula of the second-order time constant estimated value τrcest is changed according to the power running or the regenerative operation state, a method capable of obtaining the effect even in the four-quadrant operation of the power regeneration that is difficult in the conventional control. It is.

  The operation process of the first embodiment will be described based on the flowchart of FIG.

  S1: The power running regeneration determination unit 8c calculates the power running regeneration determination flag Flag using the equations (7) and (8) based on the torque command value Tref and the rotation speed detection value ωdet.

  S2: It is determined whether the power running regeneration determination flag Flag is 0 or 1. When the power running regeneration determination flag Flag = 0 (power running), the process proceeds to S3, and when the power running regeneration determination flag Flag = 1 (regeneration), the process proceeds to S4.

  S3: In the time constant estimation unit 8d, when the power running regeneration determination flag Flag = 0, the calculation of the expression (11) is performed.

  S4: In the time constant estimation unit 8d, when the power running regeneration determination flag Flag = 1, the calculation of Expression (12) is performed.

  S5: At this time, in Formulas (9) and (11) used when Flag = 0, new integration processing is not performed and the previous value is held.

  S6: Using the estimated second-order time constant estimated value τrcest, the slip angle calculation / electrical angle calculation unit 9 calculates the slip angular frequency ωslip.

  Operation mode with power running (torque command value + 50%), regenerative (torque command value-50%), power running (torque command value + 50%), and operating mode under the condition that there is an error in actual secondary resistance Rr and secondary resistance set value Rrc FIG. 4 shows the simulation result when switching between. The horizontal axis in FIG. 4 is time, and the vertical axis is torque. The simulation is performed under the condition that there is no inductance setting error.

  For comparison, FIG. 4 also shows an operation waveform without adaptive control. The adaptive control of the first embodiment is a condition that starts from 5 seconds.

  First, in the absence of adaptive control (“no adaptation” in FIG. 4), there is an error between the actual secondary resistance Rr and the secondary resistance set value Rrc, resulting in an axis shift. As a result, the torque output value cannot be output as commanded. On the other hand, in the first embodiment ("Proposal" in FIG. 4), since the error of the secondary resistance value is corrected from the start of the adaptive control, it is confirmed that the axis deviation becomes small and the torque output value matches the command value. it can.

  In the first embodiment, it is possible to reduce the error of the secondary time constant estimated value τrcest for each of the power running operation and the regenerative operation of the induction motor IM. Therefore, in the four-quadrant operation including the power running operation and the regenerative operation of the induction motor IM, it is possible to perform stable torque control in each of the power running operation and the regenerative operation.

[Embodiment 2]
The second embodiment is an invention that can cope with a parameter change during regeneration, which is difficult to cope with in the first embodiment, and can realize highly accurate control during regeneration.

  In the second embodiment, the time constant estimation unit does not simply switch the estimation formula under the power running regeneration condition at the time of regeneration, but performs parameter estimation by performing optimal time constant estimation from the current driving state based on the stability determination result. Prevent instability. This function is not in the first embodiment.

  The current command calculation unit 1, subtractor 2, 3, current control unit 4, coordinate conversion unit 5, PWM inverter 6, coordinate conversion unit 7, slip calculation / electrical angle calculation unit 9, and integrator 10 are the same as those in the first embodiment. is there. The operations of the current observer 8a and current error calculation unit 8b of the first embodiment and the current observer 11a and current error calculation unit 11c of the second embodiment are the same. In the second embodiment, the time constant estimation unit 11e of the parameter estimator 11b performs the following (based on the γ-axis current error eiγ, δ-axis current error eiδ, γ-axis current detection value iγdet, and δ-axis current detection value iδdet: 14) Estimate the first-order time constant estimated value τsest and the second-order time constant estimated value τrcest by the equation (14).

  FIG. 7 shows a stable range including adaptive control when the time constant is estimated using equation (14). In FIG. 7, the primary time constant estimated gain λs and the secondary time constant gain λr have the same value. Gray is the stable range of the control system, and white is the unstable range. As shown in FIG. 7, when the time constant is estimated using the equation (14), the entire regenerative operation region becomes unstable, and thus the estimation rule needs to be switched.

  Next, FIGS. 8 and 9 show the stable ranges when the time constant is estimated using the equations (15) and (16), respectively.

  The estimation rule of the equations (15) and (16) does not estimate the first-order time constant estimated value τsest. Since estimation is not performed, sequential estimation cannot be performed, but control is performed with the initial setting value. 8 and 9, it can be confirmed that the unstable range in FIG. 7 can be stabilized by changing the control set value.

  In the second embodiment, the stable ranges of FIGS. 7 to 9 are obtained in advance and stored in the time constant estimation expression switching determination unit 11d of FIG. The method for obtaining the stable range is a method described in Non-Patent Document 2 (a method for obtaining the stable range by the Philbitz stability discrimination method using Equations (29) and (30) in Non-Patent Document 2). ) Is used.

  Next, in the time constant estimation formula switching discriminating unit 11d of FIG. 6, whether the rotation speed detection value ωdet and the torque command value Tref input to the time constant estimation formula switching discriminating unit 11d are within the stable range of FIGS. Determine whether or not.

  For example, the switching flag Flag2 is set to 1 if the operation region is in a stable range in FIG. 7 (that is, the rotation speed detection value ωdet and the torque command value Tref are in a gray range), and the switching flag Flag2 is stable in FIG. 8 and if it is a stable range in FIG. 8, the switching flag Flag2 is set to 2. If it is outside the stable range in FIGS. 7 and 8, and is stable in FIG. The switching flag Flag2 is set to 3, and the time constant estimator 11e switches the estimation formula based on the switching flag Flag2, and calculates and outputs the temporary time constant estimated value τsest and the secondary time constant estimated value τrcest. That is, when the switching flag Flag2 is 1, the expression (14) is selected, when the switching flag Flag2 is 2, the expression (15) is selected, and when the switching flag Flag2 is 3, the expression (16) is selected. τquest and second-order time constant estimated value τrcest are calculated.

  The following operations are the same as those in the first embodiment.

  FIG. 10 shows a simulation result when the operation is performed in the second embodiment and when the time constant is estimated only by the equation (14) without switching and the operation is performed up to the regeneration region. This is a simulation result under the condition that the rotation speed (speed) is + 10% and the torque command value Tref is changed from + 10% → −10% → −40%.

  As shown in the simulation of FIG. 10, the conventional method cannot estimate well in the regenerative region (100 s to 200 s), so that a torque error occurs with respect to the command value (dotted line).

  On the other hand, in this Embodiment 2, it can confirm that it can estimate favorably also in a regeneration area | region.

  As described above, in the second embodiment (“proposition” in FIG. 10), it is possible to reduce the error of the secondary time constant estimated value τrcest for each of the power running operation and the regenerative operation of the induction motor IM.

  Therefore, in the four-quadrant operation including the power running operation and the regenerative operation of the induction motor IM, stable torque control can be performed during the power running operation and the regenerative operation.

  Further, even more accurate torque control can be realized as compared with the first embodiment.

[Embodiment 3]
The configuration of the third embodiment is the same as that of the second embodiment. In the third embodiment, the detected rotational speed value ωdet is not input to the time constant estimation formula switching discriminating unit 11d in FIG. 6, and the slip angular frequency ωslip calculated by the slip calculation / electrical angle calculation unit 9 in FIG. Then, the discrimination is made based on the slip angular frequency ωslip and the torque command value Tref. As a result, the same effects as those of the second embodiment are obtained. Note that the equation for calculating the slip angular frequency ωslip is described in equation (13).

  In the third embodiment, in FIG. 7 to FIG. 9, a stable range in which the horizontal axis is the slip angular frequency ωslip is obtained in advance and stored in the time constant estimation formula switching discriminating unit 11d in FIG. The following operations are the same as those in the second embodiment.

  Although the present invention has been described in detail only for the specific examples described above, it is obvious to those skilled in the art that various changes and modifications are possible within the scope of the technical idea of the present invention. Such variations and modifications are naturally within the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... Current command calculating part 2, 3 ... Subtraction part 4 ... Current control part 5, 7 ... Coordinate conversion part 6 ... PWM inverter 8 ... Secondary time constant estimation part 9 ... Slip calculation and electrical angle calculation part IM ... Induction motor

Claims (6)

Current control that outputs a γ-axis voltage command value and a δ-axis voltage command value based on a deviation between the γ-axis current command value and the γ-axis current detection value and a deviation between the δ-axis current command value and the δ-axis current detection value And
A first coordinate converter that converts the γ-axis voltage command value and the δ-axis voltage command value into a three-phase voltage command value;
An inverter that outputs a voltage corresponding to the three-phase voltage command value;
An induction motor driven by the voltage output by the inverter;
A second coordinate conversion unit that converts the three-phase inverter output current into the γ-axis current detection value and the δ-axis current detection value;
The γ-axis current detection value, the δ-axis current detection value, the γ-axis current error that is the difference between the γ-axis current estimation value and the γ-axis current detection value, the δ-axis current estimation value, and the δ-axis current detection Based on a δ-axis current error that is a difference between the value and a power running regeneration determination flag that is 0 when the product of the torque command value and the rotational speed detector is 0 or less, and 1 when the product is greater than 0. A secondary time constant estimator for calculating a next time constant estimate;
A slip calculation / electrical angle calculation unit for calculating a slip angular frequency and an electrical angle based on the estimated second-order time constant;
An induction motor control apparatus comprising: In the second-order time constant estimation unit,
The induction motor control device according to claim 1, wherein the primary time constant estimated value and the secondary time constant estimated value are calculated by the following equations (9) to (12).

In the second-order time constant estimation unit,
3. The induction motor control device according to claim 1, wherein the γ-axis current error and the δ-axis current error are calculated by the following equations (5) to (6).

Current control that outputs a γ-axis voltage command value and a δ-axis voltage command value based on a deviation between the γ-axis current command value and the γ-axis current detection value and a deviation between the δ-axis current command value and the δ-axis current detection value And
A first coordinate converter that converts the γ-axis voltage command value and the δ-axis voltage command value into a three-phase voltage command value;
An inverter that outputs a voltage corresponding to the three-phase voltage command value;
An induction motor driven by the voltage output by the inverter;
A second coordinate conversion unit that converts the three-phase inverter output current into the γ-axis current detection value and the δ-axis current detection value;
The first stable range, the second stable range, and the third stable range with respect to the detected rotational speed value and the torque command value are stored in advance, and the detected rotational speed value and the torque command value are within the first stable range. If there is, the switch flag is 1, if it is outside the first stable range and within the second stable range, the switch flag is 2, and if it is outside the first and second stable ranges and within the third stable range, the switch flag is set. 3, a time constant estimation formula switching discriminating unit that outputs a switching flag as 3,
When the switching flag is 1, the equation (14) is selected, when the switching flag is 2, the equation (15) is selected, and when the switching flag is 3, the equation (16) is selected. An axis current detection value, the δ axis current detection value, a γ axis current error that is a difference between the γ axis current estimation value and the γ axis current detection value, a δ axis current estimation value, and the δ axis current detection value, A second-order time constant estimator that calculates a second-order time constant estimated value based on a δ-axis current error that is a difference between
Based on the second-order time constant estimated value, a slip calculation / electric angle calculation unit for calculating an electrical angle,
An induction motor control apparatus comprising:

Current control that outputs a γ-axis voltage command value and a δ-axis voltage command value based on a deviation between the γ-axis current command value and the γ-axis current detection value and a deviation between the δ-axis current command value and the δ-axis current detection value And
A first coordinate converter that converts the γ-axis voltage command value and the δ-axis voltage command value into a three-phase voltage command value;
An inverter that outputs a voltage corresponding to the three-phase voltage command value;
An induction motor driven by the voltage output by the inverter;
A second coordinate conversion unit that converts the three-phase inverter output current into the γ-axis current detection value and the δ-axis current detection value;
The first stable range, the second stable range, and the third stable range with respect to the slip angular frequency and the torque command value obtained in advance are stored, and if the slip angular frequency and the torque command value are within the first stable range. If the switching flag is 1, outside the first stable range and within the second stable range, the switching flag is 2, and if outside the first and second stable ranges and within the third stable range, the switching flag is set to 3. , A time constant estimation formula switching discriminating section for outputting a switching flag;
When the switching flag is 1, the equation (14) is selected, when the switching flag is 2, the equation (15) is selected, and when the switching flag is 3, the equation (16) is selected. An axis current detection value, the δ axis current detection value, a γ axis current error that is a difference between the γ axis current estimation value and the γ axis current detection value, a δ axis current estimation value, and the δ axis current detection value, A second-order time constant estimator that calculates a second-order time constant estimated value based on a δ-axis current error that is a difference between
Based on the second-order time constant estimated value, a slip calculation / electric angle calculation unit for calculating an electrical angle,
An induction motor control apparatus comprising:

In the second-order time constant estimation unit,
6. The induction motor control device according to claim 4, wherein the γ-axis current error and the δ-axis current error are calculated by the following equations (5) to (6).

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