Research On Sensorless Control Of Controllable Excitation Linear Synchronous Motor

The paper,"Research on the Controllable Excitation Linear Synchronous Motor Position Sensorless Control" was supported by the National Natural Science Foundation of China"Controlled Excitation Linear Synchronous Motor Magnetic Levitation Feed Platform Operation Mechanism and Control Strategy Research?51575363?".The main content of the research is to realize the control of the controllable excitation linear synchronous motor without using the position sensor.The main research contents of the paper are as follows:?1?Research on the structure and operation mechanism of controllable excitation linear synchronous motor.Starting from the model of the rotating electrical machine,the differences in the composition and working principle of the linear motor and the rotating electrical machine are compared and analyzed.On this basis,the mathematical model of the controllable excitation linear synchronous motor is established under the d-q synchronous rotating coordinate system and the ?? rotating coordinate system,respectively.?2?Research on the control strategy of the controllable excitation linear synchronous motor feed subsystem.The more mature control strategies in the linear speed control system mainly include VF control,vector control and direct thrust control.VF control has poor dynamic performance and low control accuracy,especially when the load changes suddenly,the dynamic performance is worse,so it is not used in linear servo systems.Direct thrust control is to control the basic voltage vector and zero vector to switch according to the predetermined stator flux linkage amplitude,so there will be problems of torque and flux ripple.Vector control is to simulate the AC motor as a DC motor,so that the AC motor has the same speed control performance as the DC motor.In order to make the linear motor get the maximum torque,vector control with id=0 is adopted.?3?The speed observer of controllable excitation linear synchronous motor adopts the design of extended Kalman filter observer.The principle of Kalman filtering is introduced,and then Kalman filtering algorithm is derived.Due to the nonlinearity of the motor control system,the linear Kalman filter is extended to the nonlinear field,and the extended Kalman filter algorithm is used.In order to realize the digital realization of the speed observer,the continuous state equation of the system is discretized.Build a simulation model of CELSM speed observer based on extended Kalman filter algorithm,and compare the speed observer speed with the actual motor speed to verify the feasibility of speed observer.?4?The speed observer of the controllable excitation linear synchronous motor adopts the design of H_? extended Kalman filter observer.For the case where the prior information x₀?R_k and Q_k of the system are unknown,the prediction accuracy of the system state will be affected by the value of Q_k if using the extended Kalman filter algorithm.Using H_?filtering,the estimation error of the filter is still minimal under harsh conditions.Establish a simulation model to verify the robustness of H_? filtering.