Research On Control System Of EV Hub Motor Based On Sliding Mode Variable Structure

With the rapid development of electric vehicles,there are various drive forms of pure electric vehicles.The wheel hub motor greatly releases the space of electric vehicle chassis and improves the motor drive efficiency.In order to improve the response speed and robustness of the electric vehicle hub motor control system,this thesis has studied the hub motor sliding mode variable structure control algorithm.The main contents are divided into the following aspects:(1)This thesis analyzed the research status of electric vehicles at home and abroad as well as the advantages and disadvantages of different drive forms.On this basis,the research direction was clarified as the research of rotational speed control of hub motor.The principle of sliding mode variable structure control and improvement direction were analyzed.(2)In this thesis,the hub motor drive electric vehicle model is built in Simulink environment,and the motor speed requirement for the whole vehicle driving is obtained.In order to study the brushless DC motor control algorithm,a mathematical model of the brushless DC motor applicable to different load cases was established.(3)In this thesis,the control algorithm of brushless DC motor control algorithm based on sliding-mode variable structure was designed by using integral sliding-mode surface,exponential convergence law and load estimation value.The swarm intelligence optimization algorithm was improved by introducing strategies such as adaptive weights and dynamic changes in the sparrow population composition.The sliding mode variable structure controller was optimized by the improved sparrow search algorithm.In simulations and bench tests,the optimized sliding-mode variable structure controller responded faster and was more robust compared with PI control.