The Drive System Reserach Of Brushless DC Motor In The Electric Car

High efficiency with low pollution can be achieved by the use of the electric drive system for electric vehicles. At the same time the use and development of non-oil resources can be improved as well as the future development direction of electric vehicles promoted. With the features such as small size, high efficiency, reliable performance, wide speed range and low noise characteristics and so on, the brushless DC motor has been widely applied and developed among the electric vehicles.Aiming at the design requirements for electric vehicle drive system, the brushless DC motor with Position sensorless is used as the drive motor of the electric vehicle on the basis of the analysis of the development of electric vehicles and drive systems at home and abroad. Futher discussion and research of structural features such as working principle, control strategy of brushless DC motors is developed and some relevant foreign publications is refered to, the extended Kalman filter algorithm (EKF) is used for the position and speed estimate of the brushless DC motor. It is limited by the advantages, disadvantages and applications of the existing position sensorless detect technology. There are no parameters "adaptive" tuning function based on traditional PID control algorithm in the actual speed control process when the regulator parameters is called to change accordingly to adjust the characteristic changes of the controlled object. Therefore a PID controller based on RBF neural network design method is proposed on the basis of traditional PID controller. And then a simulation model of the brushless DC motor electric vehicle drive system is established in MATLAB. Through the analysis of motor speed, torque, current, estimated speed and position of the simulation results, the feasibility and correctness of the control algorithm is verified. The electric vehicle motor drive control system design based on STM32F407is completed and a detailed description about the design on its hardware and software parts is carried out.Through the whole article, the study is put forward for the control method of the position sensorless brushless DC motor as an electric vehicle drive motor and the rotor position estimation. Combined with the RBF neural network algorithm and the extended Kalman filter algorithm (EKF), the demands of the task is achieved.