Based On Sliding Mode Variable Structure Control Of Permanent Magnet Synchronous Motor Servo System

High performance servo control system has been widely used in the many fields, such as modern industrial, household appliance and military. The servo control system of Permanent Magnet Synchronous Motor (PMSM), which adopts advanced control strategy and digital control technology, has becoming the trend of AC servo system. The background technology used in AC servo system continues advancing. Meanwhile, market has more requirements on the performance, cost and adaptability of servo system.In this paper, the mathematical model of PMSM, theory and characteristic of PMSM vector control was analyzed, the field oriented control strategy employing i_d=0 and SVPWM is adopted, and the control scheme of PMSM servo system was established with three close-loop PI regulators. According to the problem of parameter changing and load disturbance, the method to design sliding mode controller in continuous and discrete system was analyzed thoroughly. The stability, dynamic characteristics and approach to avoiding chatter was discussed. Single surface sliding mode control based on reaching law approach was improved on, and multiple sliding mode surface control was proposed. Based on Freescale MC56F8346DSP and MATLAB/Simulink 7.1, simulation and experimental research were carried out. The result indicated that the system performance achieved the requirement of high performance servo system. Sliding mode variable structure control could be successfully combined with vector control system and improved the robustness of the system effectively.