Research On Sensorless Control Strategy Of Pernament Magnet Synchrnous Motor

Permanent magnet synchronous motor(PMSM)is widely used in industrial manufacturing,high precision CNC machine tools,aerospace and electric vehicles in recent years due to its advantages of low loss,high efficiency and high power factor.The traditional speed control system of PMSM mostly adopts PI control,because it has the advantages of simple principle and convenient adjustment.However,PI control does not show superior control performance for complex systems such as PMSM.In order to achieve high reliability and high control performance in complex working environments,it is important to obtain accurate rotor position and speed signals.The traditional method to obtain the rotor position and speed signal is to add mechanical sensors.This method is simple and convenient,but it has the disadvantages of increasing system cost,increasing system volume and may not work under the influence of surrounding environment.Therefore,in view of the above two problems,this paper takes surface permanent magnet synchronous motor(SPMSM)as the research object,and carries out the research on high-performance speed control and sensorless control of PMSM,which has certain practical application value.Firstly,this paper introduces the structure classification,the mathematical models,coordinate transformation principle and the space vector pulse width modulation(SVPWM)technology of PMSM.Using the vector control of_di(28)0 and establish integrated model of vector control system.Secondly,the sliding model control(SMC)is proposed to replace the traditional PI control in motor speed control.Analyze the traditional constant speed reaching law,point out the shortcomings of the traditional reaching law.Based on the traditional reaching law,a novel reaching law is proposed,which can not only effectively suppress the chattering phenomenon but also can further improve the reaching speed,thus solving the contradiction existing in the traditional reaching law.A sliding mode speed controller based on the novel reaching law is constructed and applied to the sliding mode speed control system of PMSM.Finally,the sliding mode observer(SMO)algorithm is used to estimate the rotor position information of PMSM.The continuous function,two-stage filtering,adaptive back-EMF observer and phase-locked loop algorithm are proposed to improve the observer.The traditional sliding mode observer and the improved observer simulation model of PMSM are built respectively.It can be found from the simulation results that the improved sliding mode observer can more accurately observe the rotor speed and position.The correctness of the improved strategy is verified.