TY - CPAPER AB - Achieving DC fault tolerance in modularmultilevel converters requires the use of a significantnumber sub-modules which are capable of generatinga negative voltage. This results in an increase in thenumber of IGBT devices in the current path, resultingin an increase in conduction losses within the converter.This paper introduces a thyristor augmented multilevelstructure called a Power-Group, offering both negativevoltage capability as well as a low conduction loss state,which can be used to construct high efficiency DC faulttolerant converters. When combined with the AlternateArm Converter topology the power-group concept hasbeen found to result in a converter topology that exhibitsvery low power-losses, high quality AC and DC currentwaveforms, while also achieving DC fault tolerance. AU - Judge,PD AU - Merlin,MMC AU - Green,TC AU - Trainer,DR AU - Vershinin,K PY - 2016/// TI - The augmented trapezoidal alternate arm converter: a power-group augmented DC fault tolerant voltage source converter UR - http://hdl.handle.net/10044/1/43291 ER -