Method and device for online measurement of rotor time constant of asynchronous motor

Abstract

The invention relates to the technical field of asynchronous motor control, and discloses a method and device for on-line measurement of a rotor time constant of an asynchronous motor. The method comprises the steps of controlling the asynchronous motor to do uniform acceleration or uniform deceleration motion within a preset time at a first rotor time constant; sampling an output torque of the asynchronous motor; judging whether the first rotor time constant is consistent with an actual rotor time constant or not according to a sampling result; adjusting the first rotor time constant to obtain a second rotor time constant according to a preset proportion if the first rotor time constant is not consistent with the actual rotor time constant; and driving the asynchronous motor to measure repeatedly by taking the second rotor time constant as a new first rotor time constant until the new first rotor time constant is consistent with the actual rotor time constant. By the method, deviation existing in measurement of the rotor time constant is effectively prevented, the measurement accuracy of the rotor time constant is improved, and the control effect of the asynchronous motor is improved.

Description

technical field [0001] The invention relates to the technical field of asynchronous motor control, in particular to a method and device for online measuring the time constant of an asynchronous motor rotor. Background technique [0002] At present, the vector control method of asynchronous motor can be divided into direct vector control method and indirect vector control method. Generally speaking, the indirect vector control method and the direct vector control method are widely used in the field of asynchronous motor control, and each has its own advantages and disadvantages. The characteristic of the indirect vector control method is that the frequency converter controls the slip angular frequency of the asynchronous motor, and at the same time indirectly adjusts the excitation component current and the torque component current through the slip angular frequency. The control effect of the indirect vector control method depends on the motor parameters, especially the roto...

AI Technical Summary

Problems solved by technology

If a frequency converter is used to inject high-frequency harmonics into the motor to obtain the rotor time constant, then under different speed conditions (that is, the frequency of the current flowing through the rotor is different) and under different temperature conditions, it is necessary to perform multiple tests for different operating conditions High-frequency harmonic injection, and the process of high-frequency harmonic injection, the motor cannot rotate normally according to the work requirements, so the high-frequency harmonic injection parameter self-learning process interrupts the normal operation of the motor, which is often the motor What the user cannot allow, even if the user allows it, such a use process is too cumbersome

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