Study On The Quasi Sliding Mode Control Strategy For The Discrete Time Of Permanent Magnet Synchronous Motor

PMSM(permanent magnet synchronous motor, PMSM) has the characteristics of its simple structure, high power factor, small size and ease of maintenance etc. With the development of power electronic technology and motor control theory, the application of the permanent magnet synchronous motor is widely used, and the control system is gradually spread and be used.Sliding Mode Control(sliding mode control, SMC) has the advantages of fast response, good robustness and easy design, so it has been very widely used in the field of power transmission. To improve dynamic quality of permanent magnet synchronous motor speed servo system, and solve the problem of PI regulator such as weak anti-jamming capability or the poor robustness, this article use the sliding model control to PMSM. Since the actual discrete control system, this control method is bound to have some chattering, in order to solve this problem, introduced the concept of reaching law. In the article, we use a new reaching law on motor control, and then compared with the conventional exponential reaching law.Simulation and experimental results show that the PMSM drive system with sliding mode controller has a good dynamic and static performance and robustness.Parameters of permanent magnet synchronous motor will change along with environment in the process of operation. And the change of parameters of permanent magnet synchronous will affect the control performance of the motor. So the on-line motor parameter identification became very important for PMSM. In the view of the current popular parameter identification, this paper chose the recursive least square method. The thesis has constructed the simulation of permanent magnet synchronous motor model whose parameters can vary online in MATLAB/SIMULINK. The objects of parameter identification are stator resistance, quadrature and the direct axis inductance and flux which may change a lot with temperature. Then based on parameter identification of the motor, make the identification results feedback to the controller, the result proved that the permanent magnet synchronous motor has a better speed control performance.