Experimental Measurements of Four Parallel-Connected Three-Phase Inverters of Railway Auxiliary Converters

In this paper, experimental measurements of four parallel-connected three-phase inverters of railway auxiliary converters were carried out. The purpose of this measurement was to verify the ability of parallel co-operation of four three- phase inverters connected to a common three-phase bus, verifying the starting sequence of the inverters and power sharing by individual converters. The converters were powered by a common high voltage AC source and the outputs were intercon- nected to form a common three-phase network. The ability to uniform power sharing was tested during 15 kW and 137 kW motor acceleration. The results showed that all inverters were able to synchronize and connect to the common bus and stable operate in parallel connection. Furthermore, the power sharing was uniform and stable under these conditions.