Analysis of a soft-switching technique for isolated time-sharing multiple-input converters

This paper explores the feasibility of active clamping techniques in isolated time-sharing multiple-input converters. Additional losses caused by energy transfer into the input switches from the leakage inductance in the isolating coupled-inductor are addressed with a common active clamping leg for all input legs. An active clamping technique is applied to isolated time-sharing multiple-input converters to minimize the additional switching losses, and the paper also conducts an operational analysis of a dual-input isolated single ended primary inductor converter (2IISEPIC) with the active clamping technique. Zero-voltage-switching can be achieved on the first-turned-on input leg and the active clamping leg with proper driving strategy and circuit parameter settings. Discussions on the effect of the active clamping technique to a multiple-input converter and the components stresses of the 2IISEPIC with the active clamping technique have also been made to assist in the design of time-sharing multiple-input converters. A prototype of the 2IISEPIC with the active clamping technique is built for efficiency and stresses verification, and it is showed that 94% efficiency is achievable at 200W output power and the component stresses are significantly reduced, especially the voltage stresses on input switches. An absolute 6 % improvement over the efficiency of the same circuit without soft-switching techniques is observed.