Control methods to achieve soft-transition of gains for a variable (n/m)X converter

摘要

Switched capacitor based converters derived from the original Dickson converter have a huge potential in meeting high power density and high efficiency demands of the power electronics industry. Originally, this type of converters offered high efficiency only at fixed voltage gains. Recently, a variant of the Dickson converter, termed as the (n/m)X converter has been proposed. The (n/m)X converter can achieve variable and fractional gains without compromising its efficiency. But, higher peak input transient current during transition from one gain level to another may lead to overvoltage stress across individual devices when compared to the fixed-gain switched capacitor converters. This is a limiting factor as the power level is increased. In this paper, two control methods are proposed to reduce/eliminate this peak current transient occurring during gain transition from one level to another. The overvoltage transient across individual switches is also eliminated. Experimental results from a 1-kW prototype validate the proposed methods.