Modeling and analysis of single phase multi string five level inverter for distributed energy resources

The main objective of this paper is to study a five level multi string converter topology for distributed energy resources based DC-AC conversion system. The modeling and analysis of multi string multi-level converter has not been presented anywhere else before. This paper proposes the Karnaugh mapping technique (which was rarely used in power electronic converters) for modeling the multi string five level converter. The proposed method can also be extended to `n´ level converter. This paper also proposes the double Fourier series analysis to determine the expressions for modulation signals with particular reference to five level design. This paper also compares the switching losses between cascaded and multi string multi-level inverters. The studied multi-level inverter topology offers strong advantages such as less switching losses, improved output voltage waveforms, lower EMI and lower THD.