Research On Sensorless Control Method Of Six-Phase Permanent Magnet Synchronous Motor

Six-phase permanent magnet synchronous motor has superior performance in power density,operation reliability,adaptability to working conditions,steady-state accuracy and other aspects,and can well adapt to the needs of high power and high reliability AC drive control system.It has a very broad application prospect in the fields of ship propulsion system,light rail and electric vehicle drive system.The positionless sensing control of the motor has the advantages of low cost,low electromagnetic compatibility requirements and small installation space,which can effectively enhance the adaptability of the speed regulation system to extreme environments.Therefore,the research on the position-free control method of the six-phase permanent magnet synchronous motor can expand the fault tolerance and application range of the six-phase permanent magnet synchronous motor.In this paper,a 30° phase shift six-phase permanent magnet synchronous motor is taken as the research object,and the position-free sensor control algorithm in the system of six-phase permanent magnet synchronous motor is studied.Firstly,in order to solve the inherent high frequency chattering problem of traditional sliding mode observer and reduce the influence of load on speed estimation error,a super-twisting sliding mode observer based on rotating coordinate system is designed.The current error dynamic equation is used to construct the Lyapunov function to analyze the stability of the system,and a new expression of speed estimation is derived.For the phase lag caused by observation delay and sampling delay in the position-free sensor control system,the phase compensation is carried out by the d-axis current loop output to reduce the Angle estimation error in the observer.The proposed super-twisting sliding mode observer and phase compensation are verified by simulation,and the simulation results under stable and transient conditions are analyzed respectively to prove the effectiveness and feasibility of the proposed method.Secondly,a closed-loop speed control method based on model reference adaptive control was proposed to solve the problem of poor speed following when the six-phase permanent magnet synchronous motor system without position sensor was disturbed by load,which is used in the positionless control system of the six-phase permanent magnet synchronous motor based on super-twisting sliding mode observer.When designing the reference model,the speed and speed acceleration of the six-phase permanent magnet synchronous motor were set as state variables,and the influence of current loop on the control system was considered.The reference model was designed as a second-order system.The adaptive rate of model reference adaptive control is designed by using Popov hyperstability theory,and the tracking errors of motor speed and speed acceleration are used as input to dynamically adjust the parameters in the controller,so as to improve the dynamic response ability of motor under loading and speed change conditions.Simulation results show that the model reference adaptive control strategy has good control effect on the response speed and overshoot of the positionless control system.Finally,an experimental platform is built for the six-phase permanent magnet synchronous motor speed control system,and the software implementation process is analyzed in detail.Experimental verification is carried out for the proposed control algorithm to verify the effectiveness and digital realization of the proposed control algorithm without position sensing.