Drive And Control Systems Of Electric Vehicles Using Induction Motor

As one of the new energy source green vehicles, the electric vehicle can not only alleviate the dependence on oil for vehicle but also reduce atmospheric pollution which caused by oil chemical combustion. The power source of battery electric vehicle is derived from battery and it is a kind of efficient and zero-pollution vehicles. The power source of hybrid electric vehicle, whose technology is the most mature currently, is derived from battery and oil. So in the development of new energy vehicles, there must be hybrid electric vehicle. For these reasons, the research of battery electric vehicle and hybrid electric vehicle is of great significance.Compared with permanent magnet synchronous motor, induction motor does not rely on rare earths, so the induction motor is chosen for the drive motor in battery electric vehicle and series hybrid electric vehicle. The drive motor is controlled by PWM converter for which the rotor flux-oriented vector control method is used. Based on the mathematical model of induction motor and the principle of vector control, the parameters of regulators in vector control system are tuned and the vector control system is validated by simulation in MATLAB/Simulink. Then the system structures and control structures of power systems for these two kinds of electric vehicles are designed. The power system of battery electric vehicle is made up of battery and bidirectional DC/DC converter. And the double closed-loop control structure which is composed of inductance current inner loop and dc-link voltage outer loop is used for bidirectional DC/DC converter. The series hybrid electric vehicle is made up of self-excited induction generator and PWM inverter. And the generator terminal voltage-oriented vector control structure which is composed of three closed-loops is used for PWM inverter.To verify the correctness of the designed systems and its control methods, the accelerating and decelerating status of these two kinds of electric vehicles are simulated and analysed. The results show that the power system can ensure the electric vehicles working normally. In addition, the batttery electric vehicles can absorb kinetic energy during the decelerating-speed process with battery, so it improves the utilization rate of energy.The experiment platforms of two kinds of electric vehicles are established and the floating-point DSP embedded controllers are used for programming. By comparing the execution time of floating-point DSP and fixed-point DSP, the advantages of floating-point DSP are validated. Moreover, the accelerating and decelerating status of two kinds of electric vehicles are tested. The test results are consistent with the simulation results. All these verify the feasibility and validity of the platform and control method.