Multi-resonant three-port DC-DC converter with power decoupling under resonant parameter deviations

This article proposes a multi-resonant three-port DC-DC converter (MRTPC) that can achieve power decoupling in the presence of deviations in the parameters of the resonant elements. The MRTPC consists of a four-element resonant tank (FERT), a three-element resonant tank (TERT), and an LC resonant tank (LCRT). Due to the fact that the FERT can be configured with first and third resonant frequencies (RF), it can transmit the energy of the fundamental and third harmonic components. By reasonably setting the RFs of the FERT, TERT, and LCRT, decoupling control of primary and tertiary energy transmission can be achieved. Due to the characteristics of the FERT, TERT and LCRT at different frequencies, decoupling the transmission of the power of the primary and tertiary frequency components can be achieved even when there is a certain deviation in the parameters of the resonant elements of the FERT. This feature can effectively reduce the cost of selecting resonant elements. To improve the efficiency of the MRTPC, an optimized triple-phase-shift modulation strategy (OTPSMS) is proposed to minimize the root mean square value of the resonant current (RMSRC). For the nonlinear problem of minimizing the RMSRC, the KKT condition is used for the optimization solution. Finally, an experimental prototype with a power level of 1 kW is built to verify the theoretical correctness of the MRTPC and its OTPSMS.