Research And Realize On The On-board Quick-charge Technology For Electric Vehile

As the energy and environmental issues are becoming more and more serious,energy-saving electric vehicles has become one of the automotive industry developmentmain directions. The existing electric vehicle charging technology which has long chargingtime and the problem of low efficiency restricts the development of electric vehicles. So itis very important to develop a suitable fast charging technology for the electric vehicles.This paper starts with the introduction of the electrochemical principle of lead-acidbattery, and then analyzes the related parameters change characteristics and the polarizationduring the battery charging process. And finally find the reason that hinders the rapidbattery charging. Combined with Maas Law, a positive and negative pulse charging methodthrough changing the width of the positive pulse is proposed. The paper chooses thepositive and negative pulse width. This paper uses fuzzy control to achieve battery chargingcombined with the discrete feature and the nonlinear feature of the battery. The input,output, membership functions and fuzzy control rules of the fuzzy controller were set. Thepaper builds a simulation model of battery charging, compares the simulation results, andthen analyzes the advantages of fuzzy control. The charging system of battery is designed.Half-bridge switching power supply topologies and bidirectional DC-DC circuit arecombined in the main circuit to achieve positive and negative pulse charging. Theparameter of the main circuit components are calculated and chosen. The buffer circuit ofthe IGBT switch and the High-frequency transformer are designed. The control circuitrealizes detection and control when charging Battery. The control circuit includes the MCUPIC18F4520, IGBT driver circuit, the temperature sampling circuit and the voltage andcurrent sampling circuit. The related software is developed. The entire main program, A/Dconversion subroutine, PWM control subroutine，fuzzy realization and discharge controlsubroutine are introduced in detail.The rapid battery charging technology is explored in this paper. The proposedcharging method for electric vehicle can significantly reduce the time and have muchsmaller damage to the battery life. And the main circuit and control circuit of the chargingdevice are designed to provide theoretical basis for the development of efficient rapid CarCharger.