Study On The Optimal Design And Control Strategy Of BLDCM For Electric Bicycles

With the continuous development of society,the transportation is also undergoing rapid changes.The production of a large number of cars leads to excessive emissions of sulfur dioxide and carbon dioxide.How to solve the pollution problems caused by the transportation industry is a hot topic today.Electric bicycles,as one of China's major transportation vehicles,use clean electrical energy,which effectively suppresses traffic pollution.Permanent magnet brushless DC motor(Permanent magnet brushless DC motor)has become the main motor of electric bicycles due to its characteristics such as not easy to damage and superior performance.The research on BLDCM is of great significance.In view of the characteristics of electric bicycles that require stable climbing and stable driving on rough roads,the following performance of BLDCM needs to be improved:(1)Ontology design not only needs to meet national standards,but also needs a wider constant power speed regulation and meet the requirements of high efficiency and low loss;(2)A new control method is used to replace the traditional proportional integral control(PI)and proportional integral derivative control(PID),to achieve accurate speed tracking performance and strong robust performance to deal with the sudden load problem when climbing.This article first introduces the research status of BLDCM at home and abroad,explains the basic structure of BLDCM,and builds a mathematical model of BLDCM.Then,a theory of practical target design method combined with traditional design method is proposed to derive the main parameters of BLDCM,and a three-phase 12/8 pole BLDCM is designed.With the help of the finite element analysis software JMAG,the electromagnetic analysis and research of the motor are conducted to verify the rationality of the design method.Finally,the traditional PI and PID double closed-loop speed control system cannot meet the increasingly high performance requirements of the electric bicycle industry,and a fractional order sliding mode controller(Fractional Order Sliding Mode Controller)is designed.The controller not only constructs the fractional sliding mode surface using the characteristics of slow change of fractional order calculus(Fractional Order Calculus)and memory characteristics,but also designs the control law in combination with the improved fractional order reaching law,so that the entire control system has excellent Speed tracking and strong robustness.Simulink in MATLAB is used to simulate BLDCM's traditional control method and fractional sliding mode control method,and the results are compared.It is verified that the fractional sliding mode control method can make the BLDCM control system have strong robustness and superior speed.Track performance,and finally build a complete experimental platform to verify the feasibility of the theory in physical control.