Bi-directional DC/DC Converter For Hybrid Electrical Vehicle

As the combination of internal combustion(IC) vehicles and electric vehicles,Hybrid electric vehicles(HEV) can lead to significant improvements in vehicle performance,energy utilization efficiency, drive distance and polluting emissions.Hybrid electric vehicle has been thought as the most promising research direction of all clean cars.Many developed countries including USA,Japan and some Europe countries ale making great efforts to develop hybrid electric vehicles.In our country,hybrid electric vehicles have been listed as one of the important projects. Therefore,it is very important to study the key technologies of HEV . As the major key techniques ,Bi-directional DC/DC converter plays an important role in interface circuit and energy recycle of HEV.Therefore,studying the Bi-directional DC/DC converter which can recycle energy is of great significance.For high power DC/DC converter applications, combining the cascade converter with the Push-pull/full-bridge converter, a novel high power cascade DC/DC converter is presented in this paper. This converter with transformer-isolated is cascaded by a boost converter and a push-pull converter, and the output uses diodes rectifier bridge rectification. By introducing an energy feedback circuit of a coupled inductor, all the switches achieve soft-switching. This paper emphasis on analyzing the operation principle of the proposed DC-DC converter in boost mode, the control strategy, and the achieve of soft-switching.According to the application of the novel bi-directional DC/DC converter in the hybrid electrical vehicle(HEV) energy management system, theoretical analysis of the operating principle, commutation process and soft switching conditions of this converter topology in the Boost and Buck operating mode, have been made in the paper.On the basis, a prototype is designed, and the experiment results are in accord with theoretical analysis.