Topology And Control For A Four-port Converter

With the increasingly severe energy crisis and environmental pollution problems, renewableenergy power system has become one of the important solving measures. A typical renewable energypower system usually contains generating, storage and consumer element. In order to overcome theshortcomings of the conventional multi-converter structure, the multi-port converter is presented as anovel and effective power electronics solution.A novel full-bridge four-port converter (FBFPC) was selected as the research target. Its topologystructure and control strategy were analyzed in detail. By reusing the bridge switches, FBFPCimproves the simplicity and power density of the topology. Single stage conversion between everytwo ports and ZVS of all primary switches were achieved to improve the overall efficiency. Centralcontrol was adopted to provide better dynamic performance and higher reliability with the eliminationof the complex communication devices.Topology of FBFPC was analyzed in detail, including five essential power flow paths and threepossible working states which were named as dual input, dual output and single input single output.Operation modes were analysed quantitatively. Voltage relationship between ports, bias current andZVS range were also introduced. A novel energy management strategy based on parallel competitionwas designed in order to overcome the defect of the tranditional “if” logic，and winning logic forFBFPC was introduced. Small-signal model was built to design the corresponding compensatingnetwork. Key parameters of FBFPC were chosen carefully, and a500W prototype was built.Experimental results verify the correctness and validity of the proposed converter and control strategy.