A Novel Direct Torque Control Method for Three-phase Asynchronous Motor

Abstract

The invention discloses a new direct torque control method for a three-phase asynchronous motor. The method first predicts the state of the motor according to the mathematical model of the motor, thereby making up for the one-beat lag problem generated by the digital controller; and then the given torque The difference from the actual torque of the motor is output by the PI regulator to output the rotation angle of the stator flux vector in a control cycle, and combined with the given stator flux amplitude to generate a reference stator flux vector, and the motor stator voltage equation is used to solve the reference voltage vector ; Finally, determine the candidate voltage vector according to the phase angle of the reference voltage vector, and calculate its optimal duty cycle, so as to determine the equivalent voltage vector applied to both ends of the motor winding. The control method of the invention has the advantages of simple operation, small amount of calculation, low switching frequency, good robustness, and can effectively restrain the torque ripple of the motor at the same time.

Description

technical field [0001] The invention relates to a novel direct torque control method for a three-phase asynchronous motor, belonging to the technical field of direct torque control of motors. Background technique [0002] The traditional direct torque control technology based on the look-up table method is widely used in the field of AC speed regulation due to its fast dynamic response, simple operation and low switching frequency. However, the shortcoming of large torque ripple limits the application of this technology to a certain extent. For further promotion, many researchers have done a lot of research on how to reduce the torque ripple in the traditional direct torque control scheme based on the look-up table method. The typical method is to solve the voltage vector The duty cycle of , but this method is computationally complex. In addition, the model predictive direct torque control, deadbeat direct torque control and other schemes can also effectively reduce the tor...

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Problems solved by technology

[0002] The traditional direct torque control technology based on the look-up table method is widely used in the field of AC speed regulation due to its fast dynamic response, simple operation and low switching frequency. However, the shortcoming of large torque ripple limits the application of this technology to a certain extent. For further promotion, many researchers have done a lot of research on how to reduce the torque ripple in the traditional direct torque control scheme based on the look-up table method. The typical method is to solve the voltage vector The duty cycle of , but this method is computationally complex

In addition, the model predictive direct torque control, deadbeat direct torque control and other schemes can also effectively reduce the torque ripple of the motor, but there are weight coefficients and rolling optimization process in the model predictive direct torque control, the system parameter debugging is cumbersome, and the amount of calculation Large; deadbeat direct torque control has a strong dependence on the accuracy of the motor mathematical model, a large amount of calculation, and poor system robustness

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