| The electric vehicle is more efficient and greener so that it is widely used worldwide.The EV battery charger is an important part of EV systems.Bidirectional chargers could reduce the impact to the grid of renewable energy systems.In this way,bidirectional chargers are widely researched nowadays.In this paper,some key points of bidirectional EV battery chargers are surveyed.The appropriate topologies are selected with improved control loop and control strategy to improve system performance.Bidirectional chargers have two stages included AC-DC converter and DC-DC converter.Firstly,the principle of bidirectional H-bridge totem pole AC-DC(PFC)converter and the model of system is analyzed.After the control loop is designed,to improve ripple of input current,LCL filter is used with active damping or passive damping.Finally,the proposed dual current feedback as active damping and mixed damping in this paper are used to improve transient performance.The proposed methods in this paper add damping resistor in series with grid inductor to eliminate overshoot.On the other hand,the operating principle of dual active bridge(DAB)under different control strategies are analyzed in this paper.Then particle swarm optimization(PSO)algorithm is used to improve TPS control strategy to optimize efficiency of system.Based on the analysis,the prototypes of PFC and DAB are built and used to verify the feasibility of the scheme and the proposed approaches in this paper. |
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