A Structure-Integrated Partially-Isolated Three-Port DC-DC Converter for Renewable Power Systems

In renewable power systems, a three-port converter is preferable to multiple two-port converters because it offers the advantages of simple structure, high efficiency and low cost. In this paper, a structure-integrated partially-isolated three-port converter is proposed. This converter has compact structure, flexible power transfer path, and the different power transfer modes can be implemented by the developed phase-shifted PWM modulation strategy. Meanwhile, the proposed converter features high voltage gain, exhibits simple parameter design, avoids voltage spikes caused by leakage inductance, and achieves zero-voltage switching (ZVS) of all switches, which makes it more practical and attractive in practical applications. The topology derivation, power transfer modes, operation principle and parameter design are thoroughly analyzed. Finally, a simulation model is built and tested on PSIM 9.1, and the simulation results validate the effectiveness and correctness of the proposed partially-isolated three-port converter.