Design and Control of An Asymmetrical Cascaded Compact Module Multilevel Inverter for PV System

Abstract

High-penetration of renewable sources and wide application of electric drives has increased the research effort in power converter technology. Multilevel inverters (MLIs) are the well-known power converters that are suitable alternative to the traditional three-level inverters for power quality improvement in different applications. Nevertheless need of more number of switches and dc sources are the shortcoming in conventional MLIs. To address this issue, this paper presents an asymmetric compact module MLI using fewer switch count and less number of dc sources. In addition, the proposed MLI has low standing voltage and less loss as compared to few state-of-art MLI topologies. The developed module can be cascaded further to increase the number of levels. Using $\boldsymbol{n}$ such modules, $16\boldsymbol{n}+1$ level output can be obtained. Selective harmonic elimination (SHE) PWM technique is analyzed to verify the operation of a 17-level MLI. MATLAB/SIMULINK platform is used for extensive simulation under different conditions such as at different modulation indices, change in frequency and load dynamic conditions. The theoretical and simulated findings are further validated experimentally on a prototype developed in the laboratory.