Ripple current reduction using multi-dimensional sliding mode control for fuel cell DC to DC converter applications

Since a fuel cell power system provides a low voltage output, in the most fuel cell vehicle and its stationary power applications, a step up boost DC/DC converter is required. In this paper, it is presented a design principle of sliding mode control for the current fed full bridge boost DC/DC converter with two different power sources, PEMFC(Proton Exchange Membrane Fuel Cell), and Ultra-Capacitor(UC)systems. Details of the sliding mode controller for the converters were derived and designed with a simple PEMFC and UC model. The proposed control scheme is based on the concept of multi-dimensional sliding mode to provide the desired shifts between phases with the help of an adaptive function for the hysteresis loop in switching elements. The ripple reduction effect in this design is demonstrated by simulation for the DC/DC converter systems under several load conditions.