Investigation Of Electric Driving System Of Two-wheel Driving Electric Vehicle Based On Permanent Magnet Brushless DC Motor

Electric vehicles, as one of the ways to solve the energy crisis and the future of the automotive industry, has been concerned and researched by enterprises and research institutions at home and abroad. The wheel drive electric vehicle, with its excellent control performance and the special structure and its wide application, will receive more attention. Based on the research of the brushless DC motor drive system of electric vehicle, this article will include the detail as bellow.Firstly, based on the electric vehicle, electric drive system and electric differential at home and abroad, for the drive system of the two-wheel drive electric vehicle, this paper designs the outer rotor permanent brushless DC motor, analyzes the motor in electromagnetic field and experiments on it. Secondly, control system of motor based on the DSP2812 chip is designed, and the article analyzes deeply the rotor position detection circuit, phase current sensing circuit, driving circuit, isolation circuit, over-current protection circuit and the waveform of the speed of the control system of the motor, the output waveform of the Hall sensor, and the control system of motor is proved to be stable. Thirdly, after the research of absolute encoder, the article proposes the design of the absolute position sensor of steering wheel based on the photoelectric switch, analyzes deeply of the hardware and software of the sensor and manufactures and tests the sample. Finally, based on the research of the Ackermann model and the measure of the relationship of steering wheel position sensor signal and the speed of internal and external wheels, the article designs the differential control system based on the speed control, and manufactures and tests the sample. By analyzes the speed of each wheel when the electric vehicle is turning, proved the feasibility of electric differential system.