A sliding mode variable structure position control method for permanent magnet synchronous motor

Abstract

The invention provides a position control method of a sliding mode variable structure of a permanent magnet synchronous motor, and belongs to the field of motor equipment. A test unit module feeds a whole disturbance error to a coupler; the coupler transmits the error obtained by coupling to a PI position controller and a PI speed controller; signals of the PI position controller and the PI speed controller are output to a PMSM vector control module through a 3s / 2s transformation module; a PWM signal output by the PMSM vector control module is output to a three-phase inverter module for controlling the permanent magnet synchronous motor. Compared with LQ feedback control, the position control LQ-VSC of the sliding mode variable structure of the permanent magnet synchronous motor has the advantages that the influence of an uncertain boundary on variable structure control is eliminated, the error generated by external disturbance is obviously reduced and a final system reaches a stable state.

Description

technical field [0001] The invention belongs to the field of motor equipment, and in particular relates to a feedback control method for a permanent magnet synchronous motor. Background technique [0002] After searching, the linear quadratic (LQ) optimal control is a commonly used method for state feedback control of linear systems. This method has been applied to the control of permanent magnet synchronous motors, but its optimal performance is only suitable for rated conditions. Its working principle is to establish the coordinate system of rotor rotation through directional control of the rotor magnetic field, transform the control signal into a three-phase current given signal, and compare it with the actual current of the three phases to generate a current tracking PWM signal. Then adopt the quadratic control to form the feedback, and the state feedback control gain is also established on the basis of the optimal control. By finding the compensation input, a new trac...

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Problems solved by technology

[0003] The above quadratic (LQ) control has the following disadvantages: (1) sensitive to parameter changes, weak ability to resist external interference; (2) poor robustness, slow dynamic response; (3) too large feedback coefficient, lead to poor system stability

Therefore, this position control method is easily affected by external factors, and these uncertain factors often affect the system performance, degrade the quality of the sliding mode control system, and even cause system instability.

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