Application Of Fuzzy And Sliding Mode Variable Structure Control In Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor(PMSM)has been widely used in production and life.Position sensorless technology not only saves the cost of position sensor,but also has better environmental adaptability.Now it is still an important research direction of many experts and scholars.The sensorless observation algorithm based on sliding mode observer has good robustness and not much dependence on motor parameters.Aiming at the buffeting problem of the traditional sliding mode observer and the problem of running at low speed and zero speed,this paper studies the sliding mode control algorithm based on the low voltage 56 V permanent magnet synchronous motor used in aviation.Firstly,the traditional sliding mode observer algorithm is used to calculate the rotor position and speed through the inverse tangent function,which verifies the robustness and convergence of the observer,but also needs to be improved.Aiming at the root of buffeting,a series of comparative simulation experiments are carried out in this paper,from the amplitude of steady buffeting to the velocity of dynamic response.(1)The method of smoothing the switching function using sigmoid function is put forward,and its observation effect on the motor speed in steady state operation is verified in the simulation experiment.(2)The Kalman filter is used to filter the high frequency harmonics in the back EMF,and the gain coefficient is adjusted by linear fitting to achieve the best filtering effect.(3)The position of rotor is obtained by phase-locked loop in real time and the parameter selection is analyzed.(4)In order to improve the dynamic performance of the sliding mode observer and reduce the overshoot of the speed step,the speed error is introduced into the fuzzy algorithm to dynamically adjust the gain of the sliding mode observer.In addition,the open loop start-up research of rotating current vector is carried out.This enables the rotor to have good robustness and load capacity from zero speed.The feasibility of the theoretical algorithm is verified by simulation.Through the feasibility verification of the self-designed hardware and software platform,it is obtained that the motor can operate in the optimal state under various running conditions.