Research And Application Of Permanent Magnet Synchronous Motor Via Sliding Mode Control Methods

Recently, the permanent-magnet synchronous motors (PMSM) have been applied widely in the capital economy, industrial production, defense and space industries and so on because they have many advantages of high power density, high efficiency, high reliability and fast dynamics etc. However, PMSM is a multivariable and strongly coupling nonlinear system, whose control performance is still influenced by the current coupling, windup, parameter variations and perturbations in practical applications. In order to meet the demands of PMSM application in the future, great progress in the PMSM control methods has to be made to ensure the development of high-performance PMSM.Sliding mode control (SMC) is one of the nonlinear control methods, which is insensitive to parameter variations and external disturbance. Therefore, SMC is paid widely attention. In the dissertation, according to the real demands of PMSM, the PMSM development and the sliding mode control technology are summarized. Especially, the application of SMC in the PMSM system is analyzed. For the problems of PMSM system mentioned above, the SMC method is applied in the PMSM control system, so as to control the current, speed and position, and further realize the sensorless control of PMSM. Based on the studies, a PMSM control system which has two modes with and without the position sensor is designed and developed. The research results are showed as bellow:(1) An adaptive current robust control algorithm based on the fast terminal sliding mode is proposed to solve the current coupling and uncertain disturbance in the conventional PMSM vector control system. The conventional PMSM vector control system can not realize the decoupling control completely. In addition, the inaccurate model would result in the uncertainty. Therefore, the fast terminal sliding mode control and adaptive control method are hybridized, and the adaptive fast terminal sliding mode current controller is designed. The convergence of the algorithm is proved by Lyapunov function, and the simulation experiments validate the reliability and applicability. The algorithm not only reduces the influence of the current coupling and back electromotive force on the system, but also strengthens the anti-interference capability of the current controller on the system uncertainty.(2) The windup phenomenon in the PMSM drive system is analyzed, and the traditional anti-reset windup method is modified. A second order integral sliding mode control algorithm is proposed to solve the parameter variation, external disturbance of PMSM and chattering of one order sliding mode system. The algorithm utilizes the integral manifold. The second order sliding mode control law is designed by the Lyapunov function approach and effectively eliminates the system chattering phenomenon. Meanwhile, an anti-windup control method is used to address the windup phenomenon of the PMSM control system. The computer simulation results are presented to verify the feasibility of the method.(3) For the friction and drive clearance of PMSM servo system, a servo control method is proposed based on the fast terminal sliding mode (FTSM). The FTSM is used for tracking the position of PMSM. In order to further alleviate the dependence of FTSM on the mathematical model of the object, we design a PMSM position tracking controller which combines the FTSM and RBF neural network. The novel method improves the control performance of PMSM. Meanwhile, for the external disturbance, a disturbance observer based FTSM method is presented to increase the control precision of position tracking system.(4) For the permanent magnet synchronous motor sensorless vector control, we analyze the observability of PMSM and present a second order sliding mode observer which is to estimate the rotor position and speed. The proposed sliding mode observer can successfully eliminate the system chattering problem, without the low pass filter in the conventional sliding mode observer and improve the precision of the estimated motor position and speed while compared to the conventional sliding mode observer.(5) According to the demand of the injecting molding machine and car air conditioning on PMSM, PMSM drive control system is developed which has two modes with and without sensor. The experimental results show that the control system is feasible and effective in the practical engineering project.