Research On Sensorless Control Strategy For Permanent Magnet Synchronous Motor Based On Sliding Mode Observer

In recent years,with the rapid development of power electronics technology and automatic control theory,the use of permanent magnet synchronous motor(PMSM)has become increasingly widespread,and it has been applied in the fields of electric vehicles,appliances,and new energy.PMSM sensorless speed control system based on sliding mode observer can achieve good speed control of the motor,and has been widely used.However,the sensorless PMSM Sliding mode control still has problems such as chattering and insufficient precision of sliding mode observer.In this paper,PMSM vector control system is taken as the research object,and a novel non-singular terminal sliding mode observer,a non-linear extended state observer,and a fractional order non-singular terminal supertwist speed sliding mode controller are studied.Firstly,the principle and structure of PMSM are studied,and its mathematical models in different coordinate systems are established using coordinate transformation.A position sensorless vector control scheme for PMSM based on sliding mode observer is designed.Secondly,a novel non-singular terminal sliding mode observer design method is proposed to address the chattering problem of sliding mode observers in traditional sensorless control for detecting back electromotive force,which improves the estimation accuracy of back electromotive force.To further reduce the chattering problem of position and speed estimation,a tangent function phase-locked loop observer is proposed,which is combined with a novel non-singular terminal sliding mode observer,Improved the convergence speed of the system,reduced chattering,and reduced errors in system estimation.To solve the chattering problem in traditional speed sliding mode control,a fractional order non-singular terminal supertwist sliding mode control method is presented.In order to improve the anti-disturbance performance of the system,a non-linear extended state observer is used to estimate the system disturbance,and it is used for feed-forward compensation.A fractional order non-singular terminal supertwist sliding mode control and a non-linear extended state observer composite speed control strategy are designed.Based on the improved sliding mode observer,a PMSM double closed-loop speed control system is constructed,which reduces the chattering and enhances the robustness of the system.Finally,in the Matlab/Simulink environment,the fractional-order non-singular terminal supertwist sliding mode controller,the non-linear extended state observer and the improved sliding mode observer are modeled,and the simulation of PMSM sensorless control system based on composite sliding mode control is completed.The simulation results show that,compared with the traditional control methods,the method designed in this paper can effectively reduce system chattering,converge faster and achieve good control results.