Input-Series-Output-Parallel System with Integrated Quasi-Two-Stage Buck-LC Converters Achieving Nature Input-Voltage Sharing

In high-input voltage applications, input-series-output-parallel (ISOP) converter system is frequently implemented due to its inherent advantages in voltage and current distribution characteristics. This paper proposes an ISOP converter system based the integrated quasi-two-stage Buck-LC (IQBLC) module, combining a front-stage Buck circuit for wide-range voltage adjustment and a rear-stage LC resonant circuit operating as an isolated DC transformer (DCX) at unity gain. The modified two-stage cascaded architecture enables the Buck circuit to achieve partial power processing characteristics, thereby facilitating high-efficiency across a wide voltage range. In the proposed converter system, both input-voltage sharing (IVS) and output-current sharing (OCS) can be naturally realized by applying common-duty-ratio control to all modules in the ISOP system. Furthermore, the topology maintains good IVS and OCS performance even under parameter mismatches among the modules. Finally, a simulation model was constructed on the PLECS platform to validate the feasibility of the proposed topology in naturally achieving IVS/OCS.