Automatic Current Sharing of Input-Parallel Output parallel Dual Active Bridge Converters with Coupled Inductors

Input-parallel output-parallel Dual Active Bridge converters are suitable for high current application with bidirectional power flow. However, parameter mismatch causes the current imbalance among the parallel modules, which leads to imbalanced loss dissipation and decreases the system capacity. This paper proposes an automatic current-sharing method for input-parallel output-parallel Dual Active Bridge converters using coupled inductors without using any current sensors or digital algorithm. The current-sharing method is analyzed in detail to derive the quantitative relation between current-sharing performance and the coupled inductance. Design consideration of the coupled inductor is also presented to show its easy implementation. Experimental results verified that the current-sharing is achieved both at steady and dynamic operations. The overall efficiency of the IPOP converter is also increased by returning part of the parallel module at light load.