Multi Leg Biderctional Dc/ Dc Converter

Abstract

The success of electric vehicles (EVs) depends greatly on a battery size, cost, lifetime, and capacity. The battery capacity of EVs has to contain enough energy to allow EV users to drive, at least, the minimum distance of ICE vehicles. However, even with very efficient EVs and combining all the available highly efficient EV technologies, the battery capacity still needs to be large. Thus, one alternative to reduce the battery size isto improve the charging infrastructure by implementing sufficient public/private fast-charging locations, which will increase significantly the EV driving range with relatively low battery capacities. However, this kind of infrastructure requires charging with higher current capability, due to the high power levels involved in the fast-charging process. In this project a bidirectional dc/dc converter with six inverter legs connected to a three-phase output is analyzed. The converter is similar to a three-phase Dual-Active-Bridge (DAB) converter with more inverter legs in parallel. These additional inverter legs increase the converter current capability, without affecting the DAB main characteristics, preserving similar modulation techniques and DAB advantages. An accurate study about the proposed topology is carried out and simulations results are presented for validating the theoretical analysis.