Capacitive-Based Isolated 1:1 Resonant Switched Capacitor DC-DC Converter

Isolation is required in many power electronics applications, such as data center power supplies, telecom supplies, electrical vehicle on board chargers, or dc microgrids. The isolation is provided using the inductive power transfer concept, implemented using the magnetic transformer. The magnetic elements add significantly to the total volume, weight, and losses of the system, decreasing its power density. Energy processing through capacitors increases the efficiency and power density by leveraging the higher energy density of capacitors. In order to decrease the system weight and loss, this article presents a novel dc-dc capacitive-based isolated, resonant switched capacitor, highly efficient, fixed gain (DCx) converter as a replacement for the transformer as the isolation element. Converter switches and resonant capacitor have the dual role of delivering the differential mode energy while providing CM isolation. The proposed converter modulation makes it inherently suitable for interleaved operation in multicell architectures, e.g., input series, output parallel, because no additional CM circulating current is generated between cells. A 100 V, 200 W GaN-based hardware prototype is built to validate the proposed resonant switched-capacitor converter, reaching an efficiency of 97.5% at full load and 98.9% at light load with a gain variation of 2.9% at full load.