Research And Design Of Control System Of Brushless DC Motors Used In Electric Vehicle

With the development of economy, science and technology, energy crisis and environmental pollution problems have become prominent problem. The traditional internal combustion engine vehicles not only demand huge number of energy, but also bring the serious environmental pollution. For solving the energy and environmental problems, electric vehicles have opened up a new field of transportation.The electrical car is the development direction of the automobile industry, so the electric vehicle motor drive system research is very essential. Brushless DC motor drive system performs particularly prominent in running efficiency and speed regulation with advantages of simple structure, convenient maintenance and low noise, which made it more widely used in the field of electric vehicles. Compared to the domestic electric vehicle industry, foreign mechanical and electrical control system are more popular, which limited the development of domestic technology and made the users under a high price, so the study of Brushless DC motor driving system has a broad market prospect and practical value.The novel driving system is designed, of which is the main researched object of this paper, the brushless DC motor, which makes the motor running smoothly with less fluctuation and noise. Firstly, motor's basic structure and the operating mode is analyzed in this paper. Then, combined with electric vehicle motor performance index and application scope, the simulation model of Brushless DC motor control system was established in MATLAB simulation platform which is based on the mathematical model of the motor and control theory. In the vector control mode,combined with the fuzzy PID control algorithm and SVPWM modulation, the optimal method is determined after comparing and analysing the simulation result,which also provide a theoretical basis for the subsequent design of hardware.According to the performance parameters of the control system, the hardware circuit design, software system design and the PCB of motor controller is accomplished with the use of American TI company's TMS320F2812 DSP chip as themain control chip. The hardware circuit contains power circuit, data processing circuit, drive circuit, inverter circuit, voltage and current sampling circuit, position detection circuit, isolation circuit, input and output control circuit. The software part mainly includes the main program, the current interrupt program, the position interrupt program and the fault interrupt program. Eventually, after completing the debugging of control system, experimental results obtained with the simulation result,which verifies the design scheme is feasible in this paper.