A Novel Higher Level Symmetrical and Asymmetrical Multilevel Inverter for Solar Energy Environment.

In this paper, a higher level symmetrical and asymmetrical multilevel inverter (MLI) with reduced device count is proposed for renewable energy systems. Multilevel inverters are recently gaining importance in renewable energy systems and other DC to AC conversion applications due to reducing voltage stress, low total harmonic distortion (THD) and high-quality output as compared to classical inverters. This paper present a basic cell unit of reduced device count (RDC) MLI with six switching devices is proposed. The topology has advantages of reduced device count over existing topologies for the same number of output levels, thus improving operating efficiency and reliability. Upon cascading two such basic cells with 12 devices synthesizes a 49 level output with an estimated THD of 1.63%. The other advantages accrued due to reduced device count are a reduction in switch driver circuits, less number of required dc voltage sources, less installation space and reduction in cost. The major benefit of the proposed topology is that it can deliver power from an asymmetrical source to load even under sudden variation in environmental conditions. The proposed MLI topology is simulated in MATLAB/Simulink environment and a laboratory prototype is developed and tested in the lab. The control paradigm is developed as the Simulink model, which is interfaced with dSPACE DS-1104 for generating control pulses to drive switches of proposed MLI topology. The experimental results validate the concept and paradigm of the proposed MLI topology. [ABSTRACT FROM AUTHOR]