Double three-phase Dual Active Bridge converter for high frequency high current applications

In a world of growing need for efficient energy conversion and distributed generation, Dual Active Bridge (DAB) converters represent a prominent converter topology given its soft switching properties and the low number of components, which allow the converter to be highly compact. Depending on the operating voltages and the transferred power, large circulating currents may occur. Parallel connection of converters is a good option in high current applications in order to adapt the converters to the use of standard semiconductors. Interleaving techniques provide, to both sides of the DAB converter, the reduction of the current ripple and the increase of its frequency. As a consequence the filters associated to the converter may be reduced. This paper introduces a new topology of DAB (named DABD3) which has a double three-phase connection in the low voltage (LV) high current side of the converter. This topology allows Zero Current Switching (ZCS) in the high voltage (HV) side switches. It has the same number of switches with the same blocking voltage of a parallel association of three single phase DAB converters. However, it presents lower ripple in the DC bus current and lower switched current in the LV side, which reduces the losses of the whole system.