Decentralized control strategy for input-series-output-parallel modular LLC resonant DC/DC converters

This paper presents an input-series-output-parallel LLC resonant converter suitable for high input voltage applications. A decentralized control strategy is proposed and analyzed so that each module is self-contained, thus improving the flexibility and reliability. The power sharing including input voltage sharing and output current sharing can be achieved only by sensing the output voltage and current of each module. A 1.25kW two-module experimental prototype with 600V input 50V output is fabricated to verify the configuration and the control strategy. An efficiency of 96% is obtained without optimization.