Design and Analysis of a Quasi-Parallel Regulated Switched-Capacitor Converter
In this research, a method to regulate switched-capacitor converters (SCC) by utilizing a regulated magnetic converter in a quasi-parallel configuration is proposed, analyzed, and experimentally verified for a telecommunication power supply application. The proposed quasi-parallel regulated switched-capacitor converter (SCC) has the advantages of high efficiency, high conversion rations, and high power density typical of unregulated switched-capacitor converter while achieving both line and load regulation. The magnetics required for the regulating converter are greatly reduced in cost and physical size due to the low voltages, high switching frequency, and partial power property of the regulating converter. This research analyzes the small-signal behavior of SCC and proposes an averaged small-signal circuit model for reduced-order models of SCC. The small-signal circuit model of SCC is then utilized to provide analysis of the proposed converter. The analysis demonstrated that besides the benefit of inherent feedback due to the quasi-parallel configuration, the control strategy for the proposed converter can be designed in the same fashion as typical PWM converters either as buck or boost converters. Datacenter power consumption makes up two percent of United States electricity consumption or 80TWhr. Roughly half of this energy is spent on cooling or lost in power conversion. Further, as data centers try to maximize compaction, the need for small and highly efficient power supplies is enhanced. Telecom power supplies often rely on large and lossy transformers to achieve large conversion ratios or to provide isolation. By utilizing a quasi-parallel regulated switched-capacitor converter, the magnetics can be removed while achieving high efficiency and power density. A 120W prototype of the proposed converter is built for a 48V to 12V telecom power supply and achieves efficiencies of 94% at 50% rated power and 93% at the full rated power. The proposed converter is shown to achieve desired load regulation and limited line regulation. The converter is experimentally shown to operate from 36V to 52V. Improvements in the efficiency, power density, and implementation of the proposed converter are included with the concluding remarks at the end of this thesis.