Abstract
Linear permanent magnet synchronous motors (LPMSM), due to their merits of simple structure, direct drive capability, less noisy and higher reliability, have now been widely applied in various industrial areas for fast and accurate position controls to increase the process output. However, the dynamic performance of a LPMSM is easily affected by the temperature change, magnetic saturation as well as the load disturbances. Hence, robust control such as variable structure sliding mode controls (VSSMC) were proposed in literature to overcome this dilemma. In view of these, the major motivation of this research lies in adapting a simple fixed structure sliding mode control (FSSMC) to design a robust position controller for LPMSM drives. Basically, the major contributions of this thesis may be summarized as follows. First, a fixed structure sliding mode controller is proposed for LPMSM drives to achieve the same robust characteristic as that of a conventional VSSMC but without chattering phenomenon. Besides, due to the available closed form solution of the closed system eigenvalues, design and implementation of the proposed controller become very simple and straightforward. Second, in order to further improve the dynamic performance, a load disturbance estimator is also proposed and added to the proposed sliding mode position controller. Finally, a prototype is also constructed by using a high speed digital signal processor, namely TMS320F2812 to simplify the hardware structure. Experimental results show that the proposed fixed structure sliding mode controller can indeed achieve the desired performance.