Permanent magnet motor sliding mode control strategy

Abstract

The invention pertains to the technical field permanent magnet motors, and relates to a permanent magnet motor sliding mode control strategy. The permanent magnet motor is controlled by adopting double-closed speed current. The permanent magnet motor sliding mode control strategy is characterized in that a sliding mode speed controller and an extended sliding mode observer are adopted in the control strategy, the sliding mode speed controller adopts an exponential approach law containing the speed error and the sliding mode surface information, the deviation between a given rotating speed and a feedback rotating speed is taken as the input quantity, and a q-axis current given value is outputted through the sliding mode control quantity; the extended sliding mode observer is used to estimate the rotor position, the rotating speed and the load torque on a real-time basis, the rotating speed and the rotor position are used to provide the information of speed closed-loop control and coordinate transformation, and the load torque is compensated to the sliding mode speed controller, so that the high-accuracy vector control of the permanent magnet motor can be realized. The control strategy of the invention can be used to make the system fast track a given speed in the dynamic state, reduce the speed overshoot and the current fluctuation, and improve the disturbance resistance performance of the system.

Description

technical field [0001] The invention belongs to the technical field of permanent magnet motors, and relates to a motor sliding mode control strategy. Background technique [0002] Since the permanent magnet synchronous motor is a multivariable, strongly coupled nonlinear system, the performance of traditional linear control such as PI control is easily affected by system uncertainty and external disturbance, which will reduce the reliability of system operation and dynamic and static performance. Sliding mode variable structure control has the advantages of strong robustness to uncertain disturbances and fast dynamic response. It can still obtain good tracking performance under external disturbances and parameter changes, and has a fast dynamic response speed. It has been successfully applied to permanent magnet synchronous motor AC servo system. [0003] Due to the discontinuous switch control in the sliding mode control, chattering becomes an inherent characteristic of th...

AI Technical Summary

Problems solved by technology

[0004] In addition, in the traditional control system, the rotational speed is obtained by the differential of the discrete rotor position output by the encoder, which will bring noise and discrete errors, and affect the dynamic response speed of the system's double closed-loop control

The disturbance of the load torque will also affect the control accuracy of the system. In the closed-loop control of the permanent magnet synchronous motor, it is assumed that the load torque disturbance is zero or a fixed value. When the load changes suddenly, the controller cannot suppress it well. Load disturbance, resulting in a large change in the motor speed

Images