Realization And Optimization Of Electric Vehicles Drive Systems

Along with the increasing problem of energy and environment, many countries have paid more and more attention to the development of electric vehicles. It is the only way to make the car industry in our country stronger and more competitive by investigating and developing independently high-powered electric vehicles.Motor drive system is one of the key sections of electric vehicles. The dissertation discusses some problems that induction motor is used for drive motor of electric vehicles, analyses mathematical model of induction motor and the rotor-flux-oriented vector control arithmetic, studies the influence of rotor time constant Tr for the direction of rotor flux and control performance in detailed, and adopts the correctional method based on temperature model for rotor time constant in the experiments. The dissertation has a simulation of direct-rotor-flux-oriented vector control. The results indicate that the control method has the rapid respond, no over respond, as well as the good abilities of restraining load disturbing, good static characteristic and dynamic characteristic. The results of simulation also provide some reference data for the application of model reference adaptive arithmetic in the drive of electric vehicles.On the base of the induction motor drive system for electric vehicles designed by project team, the dissertation designs a new induction motor drive system for electric vehicles. And the dissertation introduces the designs of hardware and software. At last, the experimental studies and road examination prove that the drive system not only has more logical structure, better reliability and stability, but also has improved performance.At the same time, because the system adopts optical encoder to measure speed of motor, it easily disturbed by electromagnetism, and result in bad aseismatic ability, bad reliability, and bad stability, which directly affect the ruggedization and needless maintenance performance of induction motor, and greatly reduce the reliability when the induction motor is used in electric vehicles. That is the fateful and feeble part. The dissertation discusses the sensorless vector control for the sake of deleting optical encoder. The dissertation thinks that speed estimate based model reference adaptive systems of induction motor is fit for electric vehicles, and makes some academic analysis and simulation studies which proves that the method can estimate well the speed of motor in wide range with low speed and high reliability. It can satisfies the...