High-Power-Density GaN-Based Single-Phase Online Uninterruptible Power Supply Danish Shahzad, Nauman Zaffar*, Khurram K. Afridi Department of Electrical and Computer Engineering Cornell University Ithaca, New York, USA ds2358@cornell.edu, afridi@cornell.edu *Lahore University of Management Sciences Lahore, Pakistan

Abstract— This paper introduces a new topology suitable for a high-power-density single-phase online uninterruptible power supply (UPS) with a common neutral between its input and output ac ports while avoiding a split dc bus. The proposed topology enables high power density by utilizing half-bridge switch structures compatible with MHz-frequency operation. High efficiency is maintained in this converter by achieving soft-switching in rectifier stage with a boundary conduction mode control strategy. A comprehensive design methodology is developed to optimize the design of this converter. A 1-kVA prototype online UPS based on the proposed topology that utilizes GaN transistors and operates at switching frequencies up to 2 MHz is built and tested. The prototyped UPS achieves a power density of 26.4 W/in3.

 LINK:https://www.semanticscholar.org/paper/High-Power-Density-GaN-Based-Single-Phase-Online-Shahzad-Zaffar/4423c3c34e093b91970248d1de813d8db2016d91