A comparison of the series-parallel compensation type DC-DC converters using both a fuel cell and a battery

This paper describes the comparison of two proposed circuits in terms of the efficiency. Series-parallel compensation type DC-DC converters have been proposed for hybrid power supplies using both fuel cell and battery. The output voltage is controlled by a series converter that regulates only the differential voltage between the fuel cell voltage and the output voltage. Although the load condition is changed, the variation of the fuel cell current is suppressed by a battery through operation of the parallel converter. The experimental results confirmed that the proposed circuit could achieve maximum efficiency point of 98.8% and 99.1% in the small differential voltage region, respectively. In addition, the loss distribution of the each proposed circuit is clarified by the loss analysis. As a result, it is confirmed that the optimizing of the reactor is required in order to improve the efficiency of the proposed circuit.