General method of reducing switching voltage stress without extra voltage-loop control for related switching-capacitor high-gain converters

High-gain converters have been used on many occasions as interfaces for multiple energy conversions. Among these converters, a family of switching-capacitor high-gain converters is widely used due to its low cost, small volume, low loss, spontaneous capacitor voltages balance, and spontaneous inductor currents average. However, one or more of the switches in these converters suffer from the issue of withstanding higher voltage stresses than the other switches, which may limit the applications of these converters at high voltages. To solve this issue, a general method for reducing the switching voltage stresses for this high-gain converter family is proposed. This method can improve many kinds of high-gain converters, which can reduce the switching voltage stresses. Based on this method, a two-phase low-stress high-gain converter is proposed. The voltage stresses of all the switches in the proposed converter do not exceed half of the output voltage of the converter. Then, based on the proposed converter feature, a control method is proposed that can make the proposed converter have the automatic capacitor voltage balancing characteristic without an extra voltage-loop control. Finally, the proposed method is verified by prototype experiments.