Design and Mathematical Evaluation of a New Multilevel Inverter Topology with Less Circuit Components for Solar and Wind Energy Conversion Systems

Multi level inverters are capable of synthesizing a near sinusoidal voltage at its terminals from multiple dc sources. The quality of synthesized output waveform depends on the parameters like number of voltage sources/capacitors, components employed in the inverter and modulation technique used to control the inverter. In this paper a multilevel inverter topology with reduced switch count has been designed. It can be used for interfacing wind and solar energy conversion systems to conventional grid. The topology has been mathematically evaluated against the similar topologies in the literature in the aspects of number of IGBTS required, driver circuits required and diodes required. The terminal voltage and the voltage THD of the inverter has been tested with two modulation schemes, they are Sinusoidal-Multicarrier Pulse Width Modulation (S-MPWM) and Nearest level Modulation Scheme (NLM). The observation concluded that even though the output THD of the inverter is high When NLM is used, the switching losses are greatly reduced. The simulations are carried out using MATLAB SIMULINK software package and the results are verified with a NLM controlled prototyp