Declining fossil fuels and their destructive effects on the environment, has made it necessary to select a suitable, inexpensive, and clean fuel replacement. Fuel cells are most adaptable choices where fossil fuels are used for producing electrical energy, specially at high powers. Similar to batteries, fuel cells are electrochemical devices that convert chemical energy produced from a chemical reaction to electrical energy. Unlike internal combustion engines, conversion of energy in fuel cells is direct conversion of chemical energy to electrical energy and therefore is very efficient. The side products of this conversion are vapour and heat. The generated water and heat can be used for regenerating electricity in a fuel cell system in order to further increase efficiency. In some fuel cells, the efficiency can be increased to about 85 percent. Recently, fuel cells are used as electrical sources for traortation, power plants, factories, military applications, etc. However, V-I characteristic of fuel cells stack shows low voltage output of fuel cells and severe drop of its voltage due to increased load current. Therefore, in order to connect fuel cells to AC and DC loads, an interface circuit is needed to increase and regulate its output voltage. Till now, a number of current and voltage source switching converters are designed and implemented for fuel cells. But generally, important features like decreasing volume, weight, price, and also low frequency current ripple at the output is neglected. Current source converters are obviously suitable choices since the fuel cell efficiency are decreased due to its output frequency current ripple. Soft switching in converters decreases switching dissipation and thus increases efficiency. In addition, increasing switching frequency will lead to smaller circuit volume. Experimental results of the proposed current source converter justify analytical analysis and simulation results.
