A Hybrid Modulation Strategy for Parameter Deviation of Three-Port Isolated Resonant DC/DC Converter

The isolated three-port resonant DC-DC converters (TPRC) are a promising solution for energy routers to integrate renewable energy sources and energy storage units into DC microgrids. However, the TPRC is sensitive to parameter deviation caused by the deviation of the leakage inductance on a multi-winding transformer (MWT) and multiple resonant component tolerance. To eliminate the impacts on power flow control and voltage gain characteristics caused by parameter deviation, the impact mechanism is analyzed. On this basis, a hybrid modulation strategy combining phase-shift with first harmonic-synchronized PWM (PS+FHS-PWM) is proposed. Under the resonant parameter deviation, adjusting the phase shift angle can restore the original voltage gain characteristic. Then, flexible power flow and decoupling between ports have been realized. Furthermore, an online phase-shift adjustment method is proposed to enable adaptive regulation according to different power transmission modes. Finally, an 8kW experimental prototype is constructed to validate the correctness of the impact mechanism analysis and the effectiveness of the proposed hybrid modulation strategy.