Comparing an Unbalance Compensating Converter with and without a Neutral Connection

Abstract: Voltage unbalances in low voltage grids have a renewed interest due to the massive deployment of single-phase grid-coupled PV inverters. Three-phase converters have the potential to compensate voltage unbalance, but commonly only have three legs. The goal of this paper is to theoretically compare unbalance compensation with or without a neutral connection, independent of the technology used for that neutral connection. It will determine how loads can be compensated and what the influence on the grid losses is. The results show that a converter with a neutral connection offers some distinct advantages and is able to compensate unbalance completely. But also the common three-phase converter has potential. The results are crucial in the decision whether or not to include a neutral connection to an unbalance compensating converter.status: publishe