Parallel operation of three-phase bi-directional isolated interleaved DC-DC converters for battery test system

In this paper, parallel control method of two 2.5 kW three-phase bi-directional isolated interleaved dc-dc converters for the battery test system is discussed. The battery test system consists of battery modules, two three-phase bi-directional isolated interleaved dc-dc converters and three-phase inverter. In discharge mode, energy from battery is delivered to grid and energy is delivered to battery from grid in charge mode. To get decent phase margin and magnitude at crossover frequency, type 3 controller is used for voltage controller. Average current sharing control method is used for maintaining each three-phase dc-dc converter current equal. By using this method, unbalance factor is improved to 1% from 8%. Two 2.5 kW three-phase bidirectional dc-dc converter prototypes are built and the proposed methods are verified through experiments.