THE PARALLEL CONNECTION OF PHASE-SHIFTED FULL-BRIDGE DC-DC CONVERTERS

When designing a high-power dc-dc converter for an Electrical Vehicle (EV) the main objectives are high efficiency, high reliability and low costs. Achieving high efficiency for wide load and high reliability for a dc-dc converter by using a single power module may be extremely difficult if the efficiency at light load must be very high and redundancy is required. Very often, the solution is to divide the total power over several power modules operating in parallel. When the dc-dc converters are operated in parallel, the load sharing can be a severe issue if no active current sharing is implemented. In this paper, several current sharing techniques are investigated and a new current sharing method for parallel connection of Phase-Shifted Full-Bridge (PSFB) converters is proposed. The new control solution is also implemented on a prototype to validate the simulations with experimental results.