Experimental verification of an improved soft-switching cascade boost converter

A soft switching cascade DC-DC boost converter is proposed in this paper. The proposed cascade single-switch converter has a higher step-up voltage gain and a wider turn-of period compared to classical boost converters, which tend to have a problem of narrow turn-of periods at higher output voltages. To reduce the switching losses, an auxiliary circuit was also added to the converter. It has a simple structure with only one main switch, one auxiliary switch and the minimum number of diodes. The proposed soft switching method enables the main switch to turn on at zero-voltage-transition (ZVT) and turn off at zero-voltage-switching (ZVS). Furthermore, the auxiliary switch and diodes are soft-switched thanks to this method. All semiconductor components operate under soft-switching, safe from any additional voltage and current stresses. The study presents the design considerations for the proposed converter, along with principle operations of the topology in a single switching period. Finally, experimental results, which were obtained on a laboratory prototype rated at 300 W, are also presented in the paper. The results show that the proposed cascade boost converter can be operated successfully in soft-switching operation for a variety of input voltages and a relatively wider load range, even at higher voltage outputs.