Research On Sensorless Control Of Permanent Magent Synchronous Motor Base On Sliding-mode Observer

Permanent magnet synchronous motor(PMSM)is easy to maintain and reliable,it has the characteristics of small size and simple structure,and it is widely used in the field of ac speed regulation.Traditional PMSM’s estimation of rotor speed and location is limited under high temperature,excessive humidity and high dust concentration,which affect the correct judgment of the system operation.In this paper,we study the sensorless technique not only solve the above problems,but also cut the system chattering,the system can recover faster when the parameters,the external environment and the input physical quantity mutate,it’s make the system robustness stronger.Firstly,this paper introduces the development status of PMSM and compares the traditional mechanical sensors and the advanced non-sensor control strategies;Then the mathematical models of permanent magnet synchronous motor based on three coordinate systems are established,analy the basic principle of motor vector control and select id = 0 control strategy.Secondly,in view of the traditional way of chattering problem,this paper adopts sigmoid function as switching function to improve sliding mode observer,through simulation and experiment verification,the chattering phenomenon is obviously weakened and the estimation accuracy is improved.at the same time.increase a negative potential observer after low pass filter,the anti-emf of the measurement noise is filtered by kalman filter,and the anti-emf observation value is more accurate than that of the anti-potential observer.;In order to simplify the rotor speed and position angle estimation,Phase-locked loop(PLL)technology is adopted to further improve the performance of sliding mode observer.In this paper,the simulation model of the motor is built in the MATLAB/Simulink environment,and the simulation results show the effectiveness of the improved algorithm.Finally,on the basis of previous research,put forward with tanh function as the control function,and compared with the sigmoid function,through theoretical analysis and simulation experiment,the correctness of the result is verified.