Design And Simulation Of Brushless DC Motor Drive System For Electric Vehicle Based On DSP

With the progress of technology and the increase of number for automobile,traditional vehicle that driven by an engine is facing increasingly severe problems, suchas energy depletion, environmental pollution and so on. These problems make itsdevelopment is limited on a certain. Electric vehicle, with several energy sources and nopollution, is a kind of new energy vehicle, which would be the mainstream developmentdirection of automobile industry in the future. As the core of electric vehicle, the designof motor drive control system will affect power performance and driving range ofelectric vehicle directly. Brushless DC motor is the deal choice of drive motor forelectric vehicle, because of simple structure, high running efficiency, no loss ofexcitation, perfect speed control performance, larger starting torque, etc.In the thesis, motor drive control system for electric vehicle is the research object.Brushless DC motor drive control system is designed based on DSP and simulated bydifferent control strategies. The main research content is as follows:To begin with, the structure and operating principle of brushless DC motor issimply introduced. Then, the control strategy that speed current double closed-loop ofmotor control system is formulated.What’s more, the hardware circuit and software program of brushless DC motorcontrol system are analyzed and designed. DSP peripheral circuit, signal detection andmodulation circuit, fault alarm circuit and signal isolation circuit, power drive circuit,communication circuit are designed with its core that special DSP chip ofTMS320LF2407A for motor control based on hardware architecture of the wholesystem. At the same time, software design is simply introduced according to modularstructure thought, including software structure, main program module, interruptsubroutine module and control algorithm. Then, the flow chart of every program is designed.Thirdly, aiming at the shortage that using traditional method of mathematicalmodeling for brushless DC motor is complex, brushless DC motor with bond graphmethod is modeled based on analyzing its physical model. When analyzing the bondgraph model, the thesis does not deduct the state function but changes the bond graphinto block graph according to simple corresponding relationship. Then the block graphis changed into simulation model of Simulink and motor controller is modeled. Thefinal simulation model of brushless DC motor control system is modeled by motormodel and controller model.Finally, the design of fuzzy adaptive PI controller is detailedly expounded. In viewof the shortage that parameters in fuzzy PI controller lack self-adjusting ability, particleswarm optimization is used to optimize quantitative factors and ratio factors of thefuzzy PI controller. Brushless DC motor control system is simulated by three differentstrategies in MATLAB/Simulink. The simulation result shows that the strategy thatfuzzy PI control based on particle swarm optimization owns better robustness, dynamicand static performance compared with PI control and general fuzzy PI control.Therefore, fuzzy PI control based on particle swarm optimization possesses certainreference significance for the intelligent control of brushless DC motor.