A Series Resonant Three-Port DC-DC Converter With Decoupling Function and Magnetic Integration

In this article, a new resonant three-port dc-dc converter with dual half bridges plus one full bridge is proposed, which can realize bidirectional power flow between each port. The resonant capacitor has three functions in the circuit: the resonant capacitor can improve the magnetic bias of half bridge converter, and therefore, the transformer saturation can be avoided; the resonant capacitor is introduced to make the inductor current close to sine wave, so that the eddy current loss of the transformer can be reduced; by setting the resonant frequency of one of the three ports equal to the switching frequency, the mutual interference between the other two ports can be reduced, so that the hardware decoupling effect is achieved. First, the operation principle of the three-port converter is analyzed. Second, the steady-state model of the converter is established, and the power transmission characteristics and soft-switching characteristics are analyzed. Third, the cause of the power coupling between ports is analyzed and the hardware decoupling method is proposed. Finally, the number of magnetic elements is reduced through magnetic integration, and the correctness of the theoretical analysis is verified by simulation and prototype experiments.