Research On Control Strategy Of Brushless DC Motor Based On Sliding Mode Variable Structure

The brushless DC motor not only maintains the good characteristics of DC motor,also uses electronic commutation instead of traditional mechanical commutation.It has the advantages of simple structure,fast response,convenient maintenance,stable and reliable performance,so it is widely used in electric vehicles,aerospace,medical devices and other fields.At the same time,with the rapid development of electronic control technology,motor permanent magnet materials and electronic components,the brushless DC motor control system with high speed regulation performance has become one of the current research hotspots at home and abroad.However,due to the characteristics of torque ripple and nonlinear system,some classic and commonly used control strategies cannot meet the high-performance control effect,which limits its application in high-precision control situations.Therefore,intelligent advanced control strategies are urgently needed.This paper makes an in-depth study of the above problems,mainly completes the following contents:Firstly,according to the working characteristics of the brushless DC motor,the mathematical model of the motor is derived by formula derivation,including three-phase voltage equation and electromagnetic torque equation,and this paper analyzed the speed regulation method of the brushless DC motor.Secondly,there is a brief introduction about fuzzy control and sliding mode control.Aiming at the shortcomings of chattering of sliding mode variable structure control in brushless DC motor control,this paper improves the sliding mode variable structure algorithm,proposes a combination algorithm of adaptive fuzzy sliding mode control,and designs an adaptive fuzzy sliding mode controller in Brushless DC motor control system.Then,the simulation model of brushless DC motor control system is built in MATLAB/Simulink by using the designed adaptive fuzzy sliding mode controller,and this paper performs off-line simulation analysis on the ordinary sliding mode control strategy and the adaptive fuzzy sliding mode control strategy respectively.The analysis results show that the improved strategy can obtain better speed regulation performance,improve control accuracy,stability,anti-interference and effectively suppress the generation of torque ripple.Finally,this paper introduces the dSPACE real-time simulation system.The hardware in the loop real-time simulation verification is carried out based on the above brushless DC motor control system.Using dSPACE hardware system and software system to complete the construction of real-time simulation model and conduct real-time hardware-in-the-loop simulation analysis.The experimental results show that the improved control strategy is consistent with the theoretical analysis,it is also proves that the improved control strategy is feasible and effective.