Research On Sensorless Control Of Permanent Magnet Synchronous Motor Based On Fractional MRAS

Permanent magnet synchronous motor(PMSM)has been widely used in industrial applications due to its high efficiency,low inertia and high torque-inertia ratio.Compared with using the speed sensor to obtain the rotor speed,the advantage of using the speed sensorless technology is to help save costs and enhance the reliability of the system.Therefore,the sensorless control technology is one of the research hotspots in recent years.The unique advantage of fractional order calculus is that it has good memory characteristics,and the use of fractional order control can improve the performance of the system to a certain extent.This paper takes surface-mounted PMSM as the object,and expands the research content of PMSM sensorless control based on fractional order theory.The main research contents of this article are as follows:(1)This article researched the mathematical model of PMSM in three different coordinate systems,introduced the main principles of SVPWM technology,built the simulation module of SVPWM algorithm and the PI control model of PMSM based on stator current,which was the fractional order of subsequent PMSM The simulation of the control method laid the foundation.(2)In order to solve the problem of low speed control accuracy of PMSM under the traditional model reference adaptive system(MRAS),this paper proposed a speed control scheme for fractional order MRAS.First,established a surface-mounted PMSM current mathematical model,on this basis,fractional order calculus was introduced,and the fractional order Lyapunov stability theory was applied to transform the traditional integer order adaptive law into a fractional order adaptive law,the exact expression of the fractional order adaptive law with respect to the speed information was deduced to identify the speed of the motor.(3)Aiming at the chattering problem generated during the PMSM speed tracking process,this paper proposed a fractional sliding mode variable structure MRAS control.The theory of adaptive sliding mode variable structure was improved,and the output errors of the reference model and the adjustable model were used to construct a fractional sliding mode surface,in order to improve the switching control rate,replaced the switching function with a saturation function with continuity,finally the Lyapunov stability theory was used to prove that thePMSM system was stable under the new fractional sliding mode variable structure MRAS,thereby identifying the speed of the motor.(4)Aiming at the above two different algorithms,simulation experiments were carried out under three different working conditions of no-load starting,sudden rotation of speed and added load to verify the feasibility of the algorithm.Simulation results show that,compared with the traditional integer-order adaptive law,under the new fractional-order adaptive law,the motor speed response is faster,the speed fluctuation is smaller when the load is added,and the speed can be stabilized faster when the speed is abrupt Compared with integer order sliding mode variable structure MRAS,under fractional order sliding mode variable structure MRAS,when adding load and speed changes,the speed chatter is smaller and the tracking accuracy is improved.