High Step-Up Converter with Low Voltage Stress for Fuel Cell Applications

High step-up DC-DC converters are considered as main components of some low-voltage and low-power fuel cell power system applications. A new DC-DC converter topology based on a two-stage switched capacitor-switched inductor multiplier is proposed in this paper. In comparison with other conventional and high step-up DC-DC converters, the proposed converter topology provides higher voltage gain and lower switch voltage stresses for the duty cycles in the range of 0.6 or higher, which is the common duty cycle range of high step-up DC-DC converters. The proposed converter consists of a novel combination of switched capacitors and switched inductors methods which lead to the reduced number of required switches and their duty cycles. The theoretical analysis is confirmed by simulation results in MATLAB/Simulink software environment results. A 100 W laboratory prototype of the proposed converter is implemented to investigate and validate the analytical and simulation results. The prototype DC-DC converter is designed and implemented to be used for a commercial 100 W PEM fuel cell stack power system.