Research On DB-FC Servo Control System Of SRM With Variable-Flux Based On Sliding Mode Variable Structure

Switched reluctance motor has many advantages such as low cost,strong reliability,flexible operation,etc.,and gradually emerges in precise speed regulation and speed regulation occasions with harsh environment.But at the same time,its application range is limited due to problems such as difficulty in motor modeling,poor adaptability of control strategy,large output pulsation,and large system noise.For high-precision servo control,reducing the torque ripple of the control system and improving the robustness of the control strategy are current key research projects.Because the direct torque control is less dependent on the switched reluctance motor model and can effectively suppress the torque ripple,this paper starts from the operating principle and mathematical model of the motor,a high-precision servo control system of the SRM is established on the basis of traditional DTC.Finally,MATLAB/Simulink is used as a simulation environment to test and analyze the results of the improved control system.Based on the traditional DTC algorithm,this paper improves the system performance in two ways,combining the high precision,low pulsation and strong robustness of the servo control system:Aiming at the problems of large torque ripple and large stator current in traditional DTC system,Deadbeat-Flux control is introduced,and a Variable-Flux DTC strategy based on Deadbeat-Flux theory is proposed.The strategy combines the motor flux data,and different values of flux and selection methods of flux change angle are given for different operation stages.In addition,this paper also combines the space voltage vector circle with the rotor position angle,re-divides the sector space,and optimizes the design of the motor starting algorithm.For the problems of large error in motor modeling,poor anti-interference ability and poor dynamic and static performance of traditional PD position controller,a sliding mode position controller is introduced,and the sliding mode is redesigned according to the operating characteristics of the servo system,which improves the traditional exponential approach law.To further improve the accuracy and anti-interference ability of the servo system,a load observer is constructed.Based on the above two improvements,this paper puts forward a control idea that combines sliding mode position controller with Deadbeat-Flux theory,and establishes a Variable-Flux DTC system based on improved reaching law sliding mode variable structure.The simulation results show that the improved system can significantly reduce the motor current,improve problems such as low motor efficiency and large copper consumption of the motor,and has better dynamic and static performance and stronger robustness.