The Research On A Bidirectional Converter System In The Hybrid Energy Storage Electric Vehicle

Along with the atmospheric pollution and energy crisis is more and more serious, the development of Electric Vehicle(sEVS) become the focus that many countries pay attention to increasingly.It becomes a hotspot to research the good startup/accelerating performance, efficient energy recycling and the One Time Traveling Mileage increasing of EVS. Ultra capacitor is a kind of physical power supply, which is well known for its prominent characteristics of large unit power, fast charging and discharging, high efficiency and long recycling life. Compared to ultra capacitor, the battery is well known for its large unit energy. The main and the auxiliary hybrid energies storage system that is made up of the battery (main energy) and the ultra capacitor (auxiliary energy) can exert respective advantages fully to improve the performance of EVS. It is a key to control the flow of energy reasonably and the distribution of power effectively with modern power conversion technology in the system, which can exert advantages of the system.Considering the work characteristic of the main and the auxiliary hybrid energies storage system, this paper selects the current two-quadrant converter and designs its main parameters. The parallel-power-MOSFET method adopted in the main circuit reduces the noisiness and increases the power density. In order to decrease the switching loss and increase the efficiency of the converter, a new snubber blueprint with soft-switching is presented based on the characteristic that ultra capacitor can be charged and discharged fast, and the circuit structure of a passive and low lossless snubber is designed, then the system mode and simulation analysis are also carried through. The ZCS and ZVS of main switches which reduce the switching loss of the bi-directional converter are realized.In order to adjust the converter quickly and communicate with the Electric Vehicle system conveniently, a multifunctional controller that adopts TMS320 LF2407A DSP of TI is designed. The control arithmetic is designed by software programming and it can be upgraded and expanded easily. The control system realizes digital closed-loop control of the current, the judge and display of malfunctions and to protect the system once there are abnormal cases. The digital...