Transformer-less local grid based 11 kV SCHB multilevel converter for renewable energy systems

Due to the variable nature of renewable energy resources and power demand by the consumers, it is difficult to operate a power system installed with only one type of renewable energy resource. The local grid based renewable generation may be the only solution to overcome this problem. In this regard, an 11 kV Series Connected H-Bridge (SCHB) multilevel Voltage Source Converter (VSC) is proposed, which is the transformer less, cost effective solution to interface the renewable generation system to the local grid directly. This paper presents the design, simulation and analysis of a Five Level (5L)-SCHB and an Eleven Level (11L)-SCHB VSC for an 11 kV local grid based renewable energy systems. The performance, cost, modulation scheme and harmonic spectra of the converter are the bases for analysis.