Research On Position Sensorless Control Of PMSM Based On Active Disturbance Rejection Sliding Mode

With the continuous development of rare earth permanent magnet materials,microprocessor technology and automatic control theory,permanent magnet synchronous motor has been widely used in various fields.However,the PMSM control system often works in a complex environment,and the traditional PI control is very susceptible to disturbances,which seriously affects the system control accuracy.At the same time,using mechanical sensors to obtain rotor position information,not only increases manufacturing costs,but also limits the use of the system to a certain extent.Therefore,this paper will study PMSM controllers and position observers based on sliding mode control theory and give disturbance compensation at the same time,to achieve PMSM control requirements under complex working conditions.The specific research content and the main results are as follows:(1)Analyzing the research status and mathematical modeling.This paper elaborates the existing PMSM control strategy,speed loop control technology and position sensorless control technology,and regards the vector control as the control strategy;on this basis,the mathematical models of the PMSM under different coordinate systems is set,and the principle of the vector control and the realization process of SVPWM are introduced at the same time.(2)Proposing a new sliding mode reaching law and switching function.This paper analyzes the causes and effects of chattering in sliding mode control,and then improves the traditional sliding mode structure;proposing a new approaching law makes the sliding mode system have a faster approaching rate when it is far away from the sliding mode surface.At the same time,it can ensure the stability of the system reaching the sliding mode surface.Through simulation,the effectiveness of the proposed reaching law is verified;in order to avoid chattering caused by the discontinuity of the switching function at the zero point,a new type of continuous switching function is proposed.(3)Establishing PMSM double sliding mode position sensorless control system.On the basis of the proposed new reaching law and switching function,the integral sliding mode surface is introduced,and the mathematical models of the sliding mode controller and the sliding mode observer are deducted respectively;in order to eliminate the high-frequency noise and ripple components in the estimate of back EMF,a back EMF observer is added to the sliding mode observer to filter its estimate;aiming at the phenomenon that the rotor position extracted by using the arc-tangent function will amplify the chattering error,a normalized phase-locked loop is designed to extract the rotor position information,the estimation accuracy of which can be effectively improved.And the effectiveness of the control method is verified by simulation.(4)Introducing the active disturbance rejection control into the sliding mode control system to realize disturbance compensation.According to the characteristics of the active disturbance rejection control that can observe the internal and external disturbances,this paper proposes a sliding mode control method based on active disturbance rejection;this method uses the extended state observer to observe and compensates the observations to the system,which will be fed back to the sliding mode control system,so as to eliminate the influence of disturbance error.The simulation results show that active disturbance rejection sliding mode control can effectively improve the control accuracy of the system.(5)Verifying the control algorithm through experiments.By building a PMSM experimental platform with TMS320F28335 as the main control chip,and designing the corresponding control program for experimental analysis,the experimental results verify the feasibility of the proposed algorithm.