Study On Position Sensorless Control Of PMSM Based On Sliding Mode Observer

Permanent Magnet Synchronous Motor (PMSM) has lots of advantages，suchas high efficiency, high energy density, high torque inertia ratio, low rotor lossesthus it becomes the focus of attention as a type of energy-saving motor；Meanwhile, it has been rapidly and widely used in many fields with thedevelopment of power electronics and electrical drives, micro electronictechnology, control theory of new motor types and rare earth permanent magnetmaterials. However, the cost for common used PMSM control with positionsensor is relatively higher and the performance of the sensor is likely to beaffected by high temperature, moist and other severe conditions, thereforeaffected the application range of the PMSM, the status quo of PMSM controlsystem was analyzed and summarized in this dissertation. The research scheme ofPMSM position sensorless control system was confirmed.With the SPMSM and IPMSM as the controlled objects, this dissertationdesigned a position sensorless control system based on sliding mode observer(SMO) to estimate the rotor position and rotate speed. This dissertation willintroduced and analyzed the basic structure and the equivalent mathematicalmodel of PMSM, according to the theory of motor mathematical model andsliding mode variable structure, this dissertation has given the mathematicalmodel of SMO and analyze its stability, in order to reduce the high frequencycomponents of back electromotive force effects on the rotor position and phasedelay, this dissertation used the phase-locked loop to track its phase, andestimated the rotor position and speed of control system.According to theoretical derivation, object to the SPMSM, its positionsensorless control system was verified by simulation, the simulation results hasindicated the validity of the control methods; Then, object to the IPMSM, itsposition sensorless control system was simulated, programmed and validated by experiments, the experimental results has shown that the design of SMO enable areliable operation of the control system, and get a more accurate positioninformation.