A Research On State Estimation Of Speed Sensorless And Control Strategy For Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)has been widely used in commercial,industrial and military fields due to its stable operation,small size,light weight and high-power density.However,with the widening of its application,the mechanical sensors used to measure the speed and rotor position are easily interfered by the surrounding environment.In order to solve this problem and reduce the cost,sensorless technology has become a research hotspot.In addition,the estimation of speed and rotor position by sensorless technology is a process of gradual convergence.In order to ensure that the speed control system has good dynamic performance in this case,higher requirements are imposed on the control strategy.Therefore,this paper takes PMSM as the research object,and focuses on its speed estimation strategy and high-performance control strategy.Firstly,aiming at the slow convergence rate of the difference between the outputs of the reference model and the adjustable model in the model reference adaptive system(MRAS),and the poor robustness of the PI adaptive mechanism in it,an Super-Twisting algorithm-based adaptive observer(STA-AO)is proposed for the speed estimation of PMSM in this paper.Based on the structure of MRAS,a corrective feedback loop is added to STA-AO,which can accelerate the convergence rate of the difference between the outputs of the reference model and the adjustable model.Then the estimated speed and rotor position can converge to their actual values more quickly.Moreover,the Super-Twisting algorithm is introduced into the adaptive observer to improve the robustness of the observer.Secondly,aiming at the problem that the dynamic performance of the speed control system is worse under the condition of sensorless,an improved non-singular terminal sliding mode composite speed controller based on disturbance observer is proposed.Compared with the traditional terminal sliding mode controller and PI controller,the improved non-singular terminal sliding mode controller can let the speed control system have better dynamic performance on the premise that the STA-AO estimates the speed.Furthermore,the disturbance observer can observe and compensate the load disturbance,then the system still has good disturbance rejection performance on the premise of a small signal function gain.The contradiction between sliding mode chatting and disturbance rejection performance has been alleviated.Finally,some simulation tests are carried out between the traditional method and the method proposed in this paper with MATLAB/Simulink simulation platform.The simulation results prove the advantages of the proposed method.Further,some relevant experiments are implemented with a PMSM controlled by a TMS320F28335,which verify the effectiveness of the proposed method.