Asynchronous motor rotor time constant online recognition method based on improved reactive power model

Abstract

The invention discloses an asynchronous motor rotor time constant online recognition method based on an improved reactive power model. According to the invention, a feed-forward for a motor stator frequency, subjected to the amplitude limiting treatment, is introduced in a conventional reactive power model. The method comprises the steps of sampling and obtaining the actual reactive power Q of a motor by an actual reactive power calculation unit; obtaining the stator inductance Ls of the motor by a stator inductance calculation unit; obtaining the reference value Isdref of the d-axis component of the stator current of the motor by an excitation controller; obtaining the theoretical reactive power Qref of the motor by a theoretical reactive power calculation unit; obtaining the reactive power deviation delta Q by a deviation calculation unit; obtaining a feed-forward value omega Q by an amplitude limiting unit; obtaining a correction value delta Tr for the rotor time constant Tr of the motor by a proportional-integral controller; and calculating the rotor time constant Tr of the motor by an arithmetic operation unit. The above method can be applied in the four-quadrant operation scenarios for the motor. By means of the method, the proportional-integral controller of the reactive power model is easy to set. At the same time, the similar rotor time constant convergence dynamic process can be obtained during the high-speed and low-speed operation process of the motor.

Description

technical field

[0001] The invention relates to the field of motor control, in particular to an on-line identification method for the rotor time constant of an asynchronous motor based on an improved reactive power model. Background technique

[0002] Indirect vector control of asynchronous motors is widely used in industry because of its simplicity, reliability and fast response. In indirect magnetic field orientation, the rotor time constant is a key parameter. If the rotor time constant used for orientation control is inconsistent with the actual value of the motor, it will lead to inaccurate magnetic field orientation of the motor, coupling of the motor stator current flux component and torque component, etc. . During the operation of the motor, the change of excitation and temperature will cause the rotor time constant to change continuously. The rotor inductance in the rotor time constant that changes with the change of the motor excitation can be adjusted online afte...

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