Analysis and synthesis of an active resonant snubber for high-power IGBT converters

[摘要] ENGLISH ABSTRACT:This thesis describes the study of two soft-switching inverter topologies that are well suited tohigh-power applications. For the first topology, namely an active resonant turn-off snubber,the existing theory is expanded with a detailed study into operation strategies and topologyprotection.This is followed by an investigation into the second topology, which is a combined snubberthat reduces both turn-off and turn-on losses. The investigation involves a detailed analysis ofthe losses in the snubber components and main devices, as well as a study into the effects ofparasitic components and diode reverse recovery on the operation of the snubber. Based on thistheory a snubber optimisation procedure is also developed. Possible operation strategies andprotection techniques were also evaluated for this topology. Single-phase experimental inverterswere used to verify the basic operation theory and switching loss prediction for both topologies.The thesis is concluded by the design and construction of a practical soft-switching threephaseinverter. After implementation the experimental inverter is used for theory verification.

[发布机构] Stellenbosch University