On the design and the efficiency of coupled step-up dc-dc converters

Step-up dc-dc converters are being extensively studied due to the diffusion of battery powered, renewable energy, traction systems and electrical power systems applications. Coupled-inductor step-up topology can be efficient when high step-up gains are required. The paper investigates the dependence of the efficiency on design parameters for a bidirectional dc-dc converter. The sliding mode control technique has been selected for controlling the dc-dc bidirectional converter, due to its intrinsic robustness against the uncertainties and disturbances. Analytical models evaluate the power losses thus allowing to calculate the converter efficiency and to make the sensitivity analysis versus the design parameters. Spice numerical simulations, performed with respect to a simple test system, allow to verify the suitability of the proposed modeling and to capture important parasitic phenomena.