Switch input supply: a load adaptive soft-switching cell usable in all bridge DC-DC and DC-AC converters

This paper proposes a soft-switching cell, based on the concept of input voltage cancellation or switching input supply, performed with a resonant commutated pole at the input of any bridge converter. The proposed auxiliary switching cell permits soft switching in all bridge topologies (half bridge, full bridge and 3-phase), in any load conditions, even with hi-directional input current. A simple control circuit, sampling the input current of the bridge converter, enables the adaptive operation of the soft switching cell, minimizing the circuit power losses.