Abstract:
The thesis presents the design and implementation of DC-DC converters with improved
step-up/step-down conversion ratio and reduced voltage stress. Firstly, a high step-down
buck converter (HSDBuC) is proposed to produce a lower output voltage at a sufficiently
higher duty ratio compared to the conventional buck converter (CBuC). The step-down
voltage conversion ratio is modified by a series-parallel transition of two identical
capacitors of a switch-capacitor cell. The cell consists of two parallel switches and two
cross-connected identical capacitors. These identical capacitors are charged in series
and discharged in parallel by producing a lower output voltage compared to CBuC at the
same duty ratio. The modified voltage conversion ratio reduces the ripples in inductor
currents and output voltage. The proposed HSDBuC utilizes a dual winding coupled
inductor to further reduce the ripples in inductor currents and output voltage. The voltage
and current stresses of the semiconductor devices employed in HSDBuC are less.
