Research On Sensorless Control Of Permanent Magnet Synchronous Motor Based On Novel Sliding Mode Observer

Permanent Magnet Synchronous Motor(PMSM)control technology has matured and has become a mainstream trend in the development and application of AC motors.It can realize motion control in various occasions such as high-speed and high-precision drive,high efficiency and low power consumption system,fast response control.Motion control in various occasions.In order to obtain better control performance,a reasonable control strategy needs to be adopted.However,no matter which control strategy is based on,it is very important to obtain the PMSM speed and rotor position information.Due to the many drawbacks of obtaining the speed and rotor position through mechanical sensors,the study of sensorless technology has important practical significance.The research in this thesis is based on the control algorithm of a novel sliding mode observer to obtain the motor speed and rotor position information.First of all,this article introduces the equations of voltage and flux linkage in the natural coordinate system of PMSM,and decoupling PMSM to simplify the design process.This thesis selects the id=0 vector control strategy for the research object of surface-mounted permanent magnet synchronous motor.The basic principles of sliding mode variable structure control are discussed,and the reasons and effects of chattering caused are analyzed,and the strategy of suppressing chattering at this stage is explained.Then,this thesis selects the stationary coordinate system of PMSM to build the current observation equation of the traditional sliding mode observer.Aiming at the problems of serious system chattering and low estimation accuracy,based on sliding mode control theory,starting from the "Quasi-Sliding Mode" and"Boundary Layer" ideas,this thesis designs a novel sliding mode observer based on piecewise composite functions.It can effectively reduce system chattering caused by discontinuous functions,and build a novel observer model on the MATLAB/Simulink simulation platform,and compare and analyze the results with traditional sliding mode observations,verifying the superiority of the novel sliding mode observer.On this basis,improve the filtering part,the cut-off frequency can change in real time with the speed to improve the adaptability of the system,and add a modified back EMF filter to form a secondary filter structure to perform secondary filtering of the observed back EMF,aiming to observe the back-EMF smoothly.The electromotive force waveform improves the anti-interference ability and observation accuracy of the system.Finally,an Hardware platform which based on YXDSP-F28335A is built,which based on the above-mentioned theory and simulation analysis,sensorless control of PMSM are completed.And the comparison and analysis of the experimental results verified that the novel sliding mode observer designed in this thesis can observe the speed and rotor position information well,and is feasible and reliable.