JP4731133B2 - Induction machine controller - Google Patents

Description

  The present invention relates to torque control of an induction machine, and in particular, maintains the calculation accuracy of induction machine speed and makes induction machine torque control highly accurate.

FIG. 3 is a block diagram showing a conventional example. 1 is an induction machine, 2 is a current detector, 3 is a power converter, 4 is torque control means, 5 is a magnetic flux calculator, and 6 is a speed calculator.
The current detector 2 detects a current i flowing through the induction machine 1.

ここで、Ｒ１は誘導機１の一次抵抗、Ｌ１は一次自己インダクタンス、Ｌ２は二次自己インダクタンス、Ｍは相互インダクタンスである。 The magnetic flux calculator 5 calculates the induction machine magnetic flux φ by the equation (1) from the current i and the voltage command v input to the power converter.

Here, R1 is a primary resistance of the induction machine 1, L1 is a primary self-inductance, L2 is a secondary self-inductance, and M is a mutual inductance.

ここで、Ｒ２は誘導機１の二次抵抗、ＦＡとＦＢは誘導機磁束φの成分である。 The speed calculator 6 calculates the induction machine speed ωm from the current i and the induction machine magnetic flux φ using the equations (2) to (4).

Here, R2 is a secondary resistance of the induction machine 1, and FA and FB are components of the induction machine magnetic flux φ.

Based on the induction machine speed ωm and the current i, the torque control means 4 outputs a voltage command v such that the magnetic flux and torque of the induction machine 1 become the magnetic flux command φ * and the torque command τ *.
The power converter 3 amplifies the voltage command v and supplies power to the induction machine 1.
With the above configuration, the torque of the induction machine 1 can be controlled to the torque command τ *. (For example, see Patent Document 1)

JP 11-069895 A

The prior art has the following problems.
When the induction machine 1 is controlled, the magnetic flux command φ * may be lowered for the purpose of weak excitation control or for voltage restriction at the end of torque control. If the induction machine magnetic flux φ decreases too much, the calculation accuracy of the equation (2) deteriorates due to the quantization error, and the induction machine speed ωm calculation accuracy deteriorates. Then, highly accurate torque control of the induction machine 1 cannot be expected.

Even if the magnetic flux command φ * aperture is stopped at a place where the calculation accuracy of the induction machine speed ωm does not drop, the induction machine magnetic flux φ may be smaller than the magnetic flux command φ * due to the influence of the motor constant setting error of the induction machine 1 and the like. There is. Also at this time, high-precision torque control of the induction machine 1 cannot be expected.
The present invention has been made to solve the above problems.

In order to solve the above problems, the following configuration is adopted.
In claim 1,
A magnetic flux command corrector that inputs an induction machine magnetic flux and a magnetic flux command and outputs a corrected magnetic flux command is added, and the corrected magnetic flux command is used for torque control of the induction machine instead of the magnetic flux command.

In claim 1 , the magnetic flux command corrector has the following configuration.
(1) An absolute value calculator that inputs induction machine magnetic flux and outputs the amount of magnetic flux.
(2) A magnetic flux fluctuation rate output device that inputs the magnetic flux amount, the magnetic flux threshold value, and the magnetic flux fluctuation rate and outputs the magnetic flux fluctuation amount.
(3) An integrator that integrates the magnetic flux fluctuation and outputs an integrated magnetic flux command.
(4) A limiter that inputs an integral magnetic flux command, an integral magnetic flux lower limit value, and an integral magnetic flux upper limit value, and outputs a lower limit magnetic flux command.
(5) A lower limit limiter that inputs a magnetic flux command and a lower limit magnetic flux command and outputs a corrected magnetic flux command.

  By using the magnetic flux command φ * as the correction magnetic flux command, the calculation accuracy of the induction machine speed ωm can be maintained, and high-precision torque control of the induction machine 1 can be performed.

  By operating the magnetic flux command, the calculation accuracy of the induction machine speed is maintained, and high-accuracy torque control of the induction machine is realized.

FIG. 1 is a block diagram showing an embodiment of the present invention, and 7 is a magnetic flux command corrector. Hereinafter, only the points of FIG. 1 different from FIG. 3 will be described.
The magnetic flux command corrector 7 receives the motor magnetic flux φ and the magnetic flux command φ *, and outputs the corrected magnetic flux command φs. The corrected magnetic flux command φs, which is the output of the magnetic flux command corrector 7, is input to the torque control means 4 instead of the magnetic flux command φ *.

By setting it as the above structure, the magnetic flux of the induction machine 1 can be operated and the calculation accuracy deterioration of the induction machine speed (omega) m by the fall of induction machine magnetic flux (phi) can be prevented. As a result, highly accurate torque control of the induction machine 1 can be expected.

FIG. 2 is a block diagram showing an embodiment of the magnetic flux command corrector 7, wherein 10 is an absolute value calculator, 11 is a magnetic flux fluctuation rate output device, 12 is an integrator, 13 is a limiter, and 14 is a lower limit limiter. It is.
The absolute value calculator 10 receives the induction machine magnetic flux φ, calculates the magnitude according to the equation (5), and outputs it as the magnetic flux amount φc.

The magnetic flux fluctuation rate output device 11 inputs the magnetic flux amount φc, the magnetic flux threshold φp, and the magnetic flux fluctuation rate φAA, and outputs the magnetic flux fluctuation amount φA according to the equation (6).

The integrator 12 integrates the magnetic flux fluctuation amount φA to obtain an integrated magnetic flux command φB.
The limiter 13 receives the integrated magnetic flux command φB, limits the lower limit value to the integrated magnetic flux lower limit value φLL, limits the upper limit value to the integrated magnetic flux upper limit value φLH, and outputs the lower limit magnetic flux command φL.

  The lower limiter 14 receives the magnetic flux command φ *, limits the lower limit value to the lower limit magnetic flux command φL, and outputs the corrected magnetic flux command φs.

The effect by having the above structure is demonstrated.
When the torque control of the induction machine 1 is performed in a state where the corrected magnetic flux command φs is equal to the magnetic flux command φ *, the magnitude of the induction machine magnetic flux φ is affected by the weak excitation control or the motor constant setting error of the induction machine 1. It is assumed that φc becomes smaller than the magnetic flux threshold φp. At this time, when the lower limit magnetic flux command φL gradually increases and the lower limit magnetic flux command φL exceeds the magnetic flux command φ *, the corrected magnetic flux command φs increases with the lower limit magnetic flux command φL. As a result, the induction machine magnetic flux φ increases.

  If the magnitude φc of the induction machine magnetic flux φ becomes larger than the magnetic flux threshold φp, the lower limit magnetic flux command φL gradually decreases, and if the lower magnetic flux command φL becomes smaller than the magnetic flux command φ *, the corrected magnetic flux command φs becomes the magnetic flux command φ *. Is equal to

  As described above, the magnitude φc of the induction machine magnetic flux φ becomes larger than the magnetic flux threshold φp, and it is possible to prevent the calculation accuracy of the induction machine speed ωm from being deteriorated due to the reduction of the induction machine magnetic flux φ. As a result, highly accurate torque control of the induction machine 1 can be expected.

  The limiter 13 is provided as a pawl for the integrated magnetic flux command φB that is the output of the integrator 12. In particular, the integral magnetic flux upper limit value φLH is necessary to prevent overexcitation of the induction machine 1.

High-accuracy torque control of the induction machine becomes possible.
It is possible to perform weak excitation control of the induction machine and highly accurate torque control at the time of voltage reduction at the end of operation.

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a block diagram showing an embodiment of the magnetic flux command corrector according to the present invention. FIG. 3 is a block diagram showing a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Induction machine 2 Current detector 3 Power converter 4 Torque control means 5 Magnetic flux calculator 6 Speed calculator 7 Magnetic flux command corrector 10 Absolute value calculator 11 Magnetic flux fluctuation rate output device 12 Integrator 13 Limiter 14 Lower limit limiter

i ... current v ... voltage command τ * ... torque command φ * ... magnetic flux command ωm ... induction machine speed φ ... induction machine magnetic flux FA ... induction machine magnetic flux a-axis component FB・ ・ ・ Induction machine magnetic flux b-axis component φs ・ ・ ・ Correction magnetic flux command φc ・ ・ ・ Magnetic flux amount φA ・ ・ ・ Flux fluctuation amount φB ・ ・ ・ Integral magnetic flux command φL ・ ・ ・ Lower limit magnetic flux command φp ・ ・ ・ Flux threshold φAA ... Magnetic flux fluctuation rate φLL ... Integral magnetic flux lower limit value φLH ... Integral magnetic flux upper limit value

Claims (1)

In the induction machine control device that calculates induction machine magnetic flux and induction machine speed from the current and voltage of the induction machine, and controls the torque of the induction machine based on the current, induction machine speed, magnetic flux command, and torque command, the induction machine An induction machine control characterized by adding a magnetic flux command corrector for inputting a machine magnetic flux and the magnetic flux command and outputting a corrected magnetic flux command, and using the corrected magnetic flux command for torque control of the induction machine instead of the magnetic flux command. A device,
The magnetic flux command corrector, the absolute value calculator for inputting the induction machine magnetic flux and outputting the magnetic flux amount, the magnetic flux fluctuation rate output device for inputting the magnetic flux amount, the magnetic flux threshold value, and the magnetic flux fluctuation rate and outputting the magnetic flux fluctuation amount, An integrator that integrates the amount of magnetic flux fluctuation and outputs an integrated magnetic flux command, a limiter that inputs the integrated magnetic flux command, an integrated magnetic flux lower limit value, and an integrated magnetic flux upper limit value and outputs a lower magnetic flux command, and the magnetic flux command and the lower limit An induction machine control device comprising a lower limit limiter that inputs a magnetic flux command and outputs the corrected magnetic flux command.

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