Study On Speed Control Of Permanent Magnet Synchronous Motor Based On Sliding Mode Observer

The sensorless speed control can simplify the hardware structure of Permanent Magnet Synchronous Motor(PMSM)speed control system,reduce the cost and improve the environmental applicability of the speed control system.In order to solve the problems of the traditional sliding mode observer(SMO)PMSM vector speed control system about the chattering and the dynamic and static performance,the improved sliding mode observer with deadbeat current grey predictive(ISMO-DCGP)control strategy is proposed which can improve the quality of the SMO speed control system.Firstly,the mathematical model of PMSM is established.According to the principle of SMO and vector speed control strategy,the SMO-PMSM speed control system has been built.Based on Matlab/Simulink simulation result,it is found that there is a significant error between the actual values and SMO estimates about speed estimation and rotor electrical angle,The system operation chattering is obvious,and the overshoot is appeared in the process of speed change when the load is switched.In order to improve the performance of the speed regulation system,the ISMO-DCGP control strategy is proposed.Secondly,based on the traditional SMO vector speed control strategy,the ISMO-DCGP control strategy is proposed.In order to reduce the system chattering,based on the variable structure control method of quasi-sliding mode,the boundary-adjustable saturation switching function is introduced to reduce the SMO estimation error and the running chatter.The parameter identification link is established to reduce the estimation error of the phase-locked loop of the motor parameter change.In the double closed-loop vector speed control system,the traditional PI regulator is replaced by the deadbeat current prediction to ensure that the motor speed is stably switched without overshoot.By introducing gray predictive control,the current state is directly fed back to the control link,which greatly improves the dynamic response of the system and ensures that the switching of the motor speed is fast and stable during load switching.The simulation results show that the ISMO-DCGP control strategy can effectively reduce the chattering of the system and improve the accuracy of the observer and the dynamic and static performance of the speed control system.Finally,The SMO-PMSM speed control platform and motor operation test platform are designed,the experimental studies were carried out under different frequency assignments and load switching.Relying on Fuji IPM intelligent power module to design three-phase inverter main circuit and corresponding isolation controlcircuit,TMS320F28335 is used as the speed control system control core to control PMSM operation.Combined with the detection device in the laboratory’s motor power experimental platform,the configuration software is designed through the S7-200 SMART and MCGS human-computer interaction interface,which can detect the running status of the speed control system.Based on the experimental results,it is found that the speed control system runs smoothly,the speed running chattering is small,the observer estimation error is small,and the load switching process is stable,which verifies the feasibility of the scheme.