Analysis and design of high power density resonant switched-capacitor converters

Abstract

This thesis is motivated by the desire for power electronics designers to create power electronic converters that have high energy density (are very small) and high efficiency (few losses). Switched-capacitor (SC) topologies that utilize the high energy density of capacitors are a candidate for fulfilling these two criteria. However, there are inherent limitations in conventional switched capacitor converters where a designer is required to make a trade-off between efficiency and capacitor energy density utilization. One way to overcome this obstacle is to utilize resonance in a SC converter. This work proposes a resonant, voltage step-up Dickson SC converter. A single inductor is utilized to achieve zero current switching of all transistors, which allows for high switching frequency and high conversion efficiency. A split-phase control scheme is used in order to eliminate the current transients associated with the Dickson SC converter and the resultant power loss. Employing these techniques, a Dickson SC converter prototype is implemented with GaN transistors. The converter is able to achieve high power density while maintaining high efficiency because of the control techniques that are employed.