Research On Hybrid Sensorless Control Strategy Of Permanent Magnet Synchronous Motor In Full Speed Range

Permanent magnet synchronous motor(PMSM)is widely used in industrial field due to the great advantages of simple structure,high efficiency,and small size.The traditional PMSM control system uses position sensors to obtain the information of motor rotor position and speed,the use of position sensor will increase the volume and cost of motor control system,and the accuracy of position sensor will decline in bad operating environment,which will affect the stability of motor control system.Therefore,the research on sensorless control technology of PMSM has important practical significance.This paper studies the sensorless control technology of PMSM in the full speed range,The specific research contents and main results obtained are as follows:(1)Analyse the researching status.The research significance and research status of sensorless control of PMSM are introduced.According to the PMSM speed range,the motor operation stage is divided into medium-high-speed operation stage and low-speed stage.The classification and control principles of PMSM sensorless control strategies in different operation stages are introduced in detail.(2)Research on Vector Control Strategy of PMSM.The classification and basic structure of PMSM are introduced.the mathematical models of PMSM in different coordinate systems are deduced according to the principle of coordinate transformation.We detailed elaborate the vector control principle and SVPWM algorithm of PMSM.(3)Design of improved sliding mode observer(SMO).In the stage of high-speed operation of PMSM,the SMO method is used to realize the position sensorless control?The principle of sliding mode observer of PMSM is introduced in detail,the causes of chattering in the traditional SMO are expounded.Aiming at the chattering problem of traditional sliding mode observer,an improved SMO is proposed.The specific improvement strategy: The sinusoidal saturation function is used to replace the traditional symbolic function as the switching function,and fuzzy control rules are designed to adaptively adjust the boundary layer of sinusoidal saturation function.Finally,a new variable exponential power reaching law is used to replace the traditional constant velocity reaching law,which effectively reduces the chattering of the SMO system.In order to further enhance the anti-disturbance performance of the control system,a new sliding mode speed controller is designed to replace the PI regulator of the traditional speed loop.the effectiveness of the improved SMO and the new sliding mode speed controllerv is verified by the simulation model.(4)Optimization of the pulsating high-frequency voltage injection method.In the low-speed operation stage of PMSM,the pulsating high-frequency voltage injection method is used to realize the position sensorless control.The basic principle of pulsating high-frequency voltage injection method and the rotor initial position detection method are introduced in detail.Aiming at the influence of the dead time effect for inverter on pulsating high-frequency voltage injection method,the second order generalized integrator(SOGI)is used to optimize it,which effectively suppresses the harmonic interference and improves the estimation accuracy of the control algorithm.The hysteresis switching method is used to switch the sliding mode observer method and the pulsating high-frequency voltage injection method,the sensorless full speed range control of PMSM is realized.The effectiveness of the optimized pulsating high-frequency voltage injection method and the hysteresis switching method is verified by simulation experiments.(5)Verifying the control algorithm through experiments.The hardware design and software design of the experimental platform of PMSM control system are introduced,the effectiveness of two sensorless control algorithms and the hysteresis switching method are verified on the experimental platform.