Research On BLDC Motor Control System For Electric Vehicle

Electric Vehicle (EV) has no population. It can supply with several kinds of energy. Also its energy efficient is high. These advantages solved the problems such as energy, population and road capacity that made by traditional vehicle. EV technology has become the researching focus. The research of EV technology in our country has just begun. All the key technology has to be solved. Motor and its control technology is one of the most important technologies that must be solved firstly.Firstly this paper introduced the status quo of EV investigation and development. Compared with several type of motors which used for EV, it can be found that the permanent magnetic brushless DC motor is one of the best drive motors for EV and this motor has good foreground. Then the problem existed for the BLDC control is showed including position detection, current measurement and control, energy feedback and field weakening. In the second chapter the theory and math model of BLDC is introduced, and then the problems existed is analyzed separately, and rational project is proposed. Then the hardware and software of the motor control system are introduced in the third and fourth chapters separately. On the basis of the foregoing chapters, in the fifth chapter some experiments results are given and also the results analysis is included.The main works and conclusions in this paper are as follows:(1) According to the EV characteristic and requirement, BLDC control system based on TMS320LF2407A is designed. A HEV that equipped this motor control system is checked and accepted by EV expert group of the 863 plans in the first period.(2) The energy feedback theory for the PM BLDC motor control system is analyzed and many experiments are made. The energy feedback is realized and a lot of experiment data are gained. It lays a foundation for late research.(3) The current sample mode and control technology for PM BLDC are analyzed and also many experiments are made.(4) The possibility of PM BLDC field weakening is analyzed, and some experiments were made. It showed that field weakening for general PM BLDC is limited to a strait range. This motor structure must be designed again in order to satisfy the EV requirement.