A bidirectional resonant CLLC converter combining three-level characteristic and bipolar DC structure

In order to meet the efficient and convenient usage requirements for bidirectional DC-DC converters in some fields such as DC microgrids and vehicle power conversion systems, a bidirectional resonant CLLC converter combining three-level characteristic and bipolar DC structure is used and analyzed in this paper. A three-level topology is adopted in the resonant CLLC converter, which can achieve stable and wider range voltage regulation through the frequency adjustment combined with duty cycle and phase shift modulation, and can also increase the flexibility of control strategy. The application of bipolar DC structure enables this resonant CLLC converter to have multi-port on one side, and the method of using two interleaved inductors combined with synchronous rectification enables the output voltage of the converter to maintain a certain balance. In this paper, the voltage gains and running states of the three-level regulation method are analyzed, and then these operation modes and the bipolar DC voltage balance effect of the converter under synchronous rectification control are verified by the experiment results. A topology combining three-level characteristics and bipolar DC structure based on a bidirectional resonant CLLC converter is analyzed in this paper to improve the voltage regulation range of the converter system. One side of this converter is a three-level structure, and the voltage can be adjusted by controlling the duty cycle and phase shift of the switches. The other side of the converter is a bipolar structure, which enables the converter to have dual ports and a wider output voltage range. image