Application research of an electric vehicle DC fast charger in smart grids

Abstract

Popularization of charging station promotes wide applications of electric vehicle (EV). With the increase in the number of charging station, the problem of grid pollution becomes worse and worse. To improve the utilization rate of EV, the charging hours must be decreased. At present, most EVs start charging instantaneously under almost rated power of the charger. Large-scale EVs charging without adjustment will impact the smart grids. The capability of smart grids will restrict the number of charging station; furthermore, it will affect applications of EV. To solve the above problem, it is necessary to design a smart charger, as an important part of charging station, with unit power factor and with the function of fast charging. This article proposes a novel unit power factor DC fast charger for EV charging stations. This DC fast charger includes two modules: the input module is three-phase PWM rectifier and the output module is the phase-shift full-bridge converter. The two modules are controlled by only one DSP - TMS320F2812, which has abundant outside interfaces, to improve cooperating ability of two converters and the dynamic response of the charger. A prototype of 10 kW Charger is constructed. The experimental results show that the novel DC fast charger has excellent electrical characteristics, and it can be applied to the EV charging stations in smart grids.