An Interleaved Control Strategy for Input-Series Output-Parallel System with Three-Level Boost Converter+Full-Bridge LLC Converter

LLC resonant converters are known for their advantages such as soft switching technology, high power density, and high efficiency. In order to achieve wide gain range under wide input voltage, reduce the voltage stress on the switching devices, and ensure that the output voltage is stable, this paper proposes an input-series and output-parallel (ISOP) system composed of a three-level boost (TLB) converter and a full-bridge LLC (FB-LLC) resonant converter in cascade. The three-level boost converter provides high voltage conversion capability for output voltage regulation. The LLC resonant converter achieves ZVS (Zero Voltage Switching) and ZCS (Zero Current Switching) within the full load range, then reducing switching losses and improving system efficiency. In order to improve the dynamic response of the system, this paper adopts an interleaved control strategy. By employing dual-loop pulse phase-shift control in the three-level boost converter and switch interleaving control in the LLC resonant converter, the output voltage ripple can be reduced, and the stability and response speed of the system can be enhanced. Finally, the feasibility of the ISOP system under interleaved control is verified through Simulink simulations.