A hybrid DC-DC converter for fuel cells powered laptop computers

In this paper a hybrid dc-dc converter for a fuel cell powered laptop computer is proposed. In the proposed system the ac-dc adapter, the fuel cell and its components are assumed to be packaged into one external unit. The purpose of the hybrid dc-dc converter is to suitably control the energy flow from fuel cell, battery and supercapacitor to enable all day computing. A design example is presented to appropriately size the fuel cell stack, Li-Ion battery and supercapacitor modules required for a typical electrical load on a laptop computer. Analysis, design and control aspects of the hybrid dc-dc converter are presented to meet performance requirements. Simulation results verify the performance of the system under various input and output power conditions. Experimental results obtained with the prototype system employing a 30 W fuel cell show that the hybrid converter is capable of successfully interfacing the internal dc-link with the multi-input power source. The source switching between the fuel cell and battery is seamless from the dc-link standpoint as the voltage remains stable regardless of the employed source.