Modular battery energy storage system based on one integrated primary multi-secondaries transformer and its independent control strategy

In order to solve the inconsistency of the battery pack in the traditional battery energy storage system, a new type of battery module energy storage system topology and control strategy based on flexible grouping is proposed--Modular Battery Energy Storage System Based on One integrated Primary multi-secondaries transformer. Different from commonly used full-power control mode, the part-power control mode is adopted in this paper. The current flowing through the switches is the difference of each battery module current and the average current of all battery modules. By applying part-power control method, the system volume, cost and loss will be effectively reduced. Based on the dual active bridge converter and one integrated primary multi-secondaries transformer, phase shifting control strategy is implemented to control part of the charging and discharging current of each battery module independently, which makes each battery module work under the best condition and helps in improving the energy utilization. Based on analyses of the data of the passenger car battery after 3 years of actual operation, Simulation results show the correctness and superiority of this topology and its control method.