Development of a 200 W converter for phosphoric acid fuel cells

Fuel cells (FCs) have the advantage that they can be used in remote telecommunication sites with no grid connectivity as the majority of telecommunication equipment operates from a DC voltage supply. Like any other fuel cell, the phosphoric acid fuel cell (PAFC) output power is highly unregulated leading to a drastic drop in the output voltage with changing load value. Therefore,various DC¿DC converter topologies with a wide range of input voltages can be used to regulate the fuel cell voltage to a required DC load. An interleaved synchronous buck converter intended for efficiently stepping down the energy generated by a PAFC was developed. The design is based on the Texas Instruments (former National Semiconductor) LM5119 IC. A LM5119 evaluation board was redesigned to meet the requirements for the application.