Hot-swappable modular converter system control for heterogeneous batteries and ESS

Abstract

This study proposes a modular bidirectional converter system for hot-swappable energy storage systems (ESSs). The proposed modular converter has a four-leg interleaved structure, and therefore it can reduce input current ripples and is suitable for secondary cells. Moreover, if any of the legs fails, hot-swap is available through phase control inside the converter. The modular converter uses an independently controllable battery as an input power source, allowing the charge and discharge control according to each stated of charge (SOC). The output voltage of the converter circumvents the module in the event of a high-voltage output control and a fault (exchange due to battery life, repair of converter) through the cascade-type bypass, thereby enabling continuous operation. The hot-swap operation of the proposed modular ESS converter system and the charge and discharge control algorithm according to battery SOC are verified by experiment.