High-gain DC-DC converters for high-power PV applications: Performance assessment

Abstract

Conventional non-isolated DC-DC converters provide limited practical gains at high duty cycles due to their parasitic losses. Such trend is not suitable for renewables grid integration due to the high required gain, while isolated DC-DC converters utilize costly and lossy high-frequency transformers with limited power capability. Alternatively, connecting conventional DC-DC converters in different combinations can provide higher gains, up to MVDC levels in PV applications, while maintaining adequate efficiency margin through design optimizations. This paper addresses cascaded and/or series connection of DC-DC converter modules as a solution to the high gain requirement, and provides a performance assessment based on Cuk and Single-Ended Primary Inductor Converter (SEPIC) topologies. Theoretical analyses are performed, and their trends are experimentally-verified by lab-scale prototypes. � 2018 IEEE.