A high-performance V6 converter for fuel cell power conditioning system

A power conditioning system that includes a DC-DC converter and a DC-AC inverter tends to draw both high frequency switching and low-frequency load current ripples at the input. Such ripple currents may shorten fuel cell life span and worsen the fuel efficiency. The most obvious impact is it tends to reduce the fuel cell output capacity because the fuel cell controller trips under instantaneous over-current condition. In this paper, a high performance fuel cell power conditioning system is presented to show superior efficiency and high-frequency ripple current elimination using a multiphase DC-DC converter and low-frequency ripple current elimination using a multiple loop control technique. The proposed power conditioning system has been designed, built, and verified with both computer simulation and hardware experiment using a proton exchange membrane fuel cell. Test results show the entire high-performance fuel cell power conditioning system not only achieves high efficiency of 97% for individual power conversion stages but also eliminates the current ripple going back to fuel cell with a cost effective control design.