A Novel Eight-Channel Grid-Connected Three Phase Converter

Abstract

In order to improve power quality to reduce harmonics in ac mains, traditional three phase grid-connected converter was usually working at high switching frequency mode, which caused system’s low conversion efficiency and restricted its application in high power conversion. This paper studied an eight-channel threephase converter based on space vector modulation (SVM) plus phase shift control strategy in which its main circuit was composed of two groups multipulse converters with the same structure by parallel connection at DC side and series at AC side. This novel converter can output sine wave with very little harmonic content at AC side under three times the fundamental frequency switching mode, thus the high quality of grid current can be obtained with very small filter used at grid side. A 50kW eight-channel grid-connected three phase inverter prototype is developed, experiment results show that the multipulse three phase converter has the advantages of high quality grid current, low switching frequency, good transient performance and system reliability.