An Optimized Design Of EV On-board Charger With Wide Operating Range

Recently,the research of on-board charger(OBC)applied to electric vehicles(EVs)has received extensive attention.This paper proposes an improved method for OBCs operating with a wide range of output voltage and transfer power.It regulates the input voltage of the DC-DC converter along with the output voltage.By adopting this,the efficiency can be improved and kept at a high level with a simple control strategy.An OBC consists of an AC-DC converter and a DC-DC converter.In this paper,the operating principle of dual active bridge(DAB)is introduced,including two control strategies-phase-shift control and PWM plus phase shift control.On the basis of the operating characteristic and loss analysis of DAB,a new method is proposed.Compared with the traditional method,the input voltage of DC-DC converter is not constant but can be regulated.By regulating the input voltage along with the output voltage of DAB,DAB can operate at an optimized condition.Simulink model is built to verify the feasibility.Besides,this paper analyzes the modulation method and the operating principle of bidirectional full-bridge PFC.In terms of software design,the detailed processes of small signal modeling and controller design are introduced.The rationality of control parameters are demonstrated by simulation results.According to theoretical analysis,3.3kW experimental platforms of DAB and a 3.3kW experimental platform of PFC are built to demonstrate the validity and the advantages of the proposed system.