In Press

Abstract

Electricity demand is continuously increasing due to dependency of industrial, commercial and residential users on advance technology. To address this issue is the prime need of time. Modern trend is to harvest energy from renewable sources such as wind, PV etc, which is environmental friendly and economical comparatively. However, as Renewable-Energy- Sources (RES) are sprinkled in small scale by the nature, so usually it is difficult to get a scalable amount of energy. Furthermore, the power quality is much affected due to varying nature of these RES sources. To get maximum efficiency and reliable operation from RES, different inverter topologies are presented. This paper highlights four types of Multilevel-invertertopologies commonly used for smoother, reliable and efficient operation of renewable energy sources (RES) in medium and high power applications. These are NeutrallPoint-Clamped-(NPC) or also called Diode-Clamped MultiiLevel-Inverter(DCMLI), Flying-Capacitor(FCMLI), Cascaded-Inverterr(CMLI) and a Hybrid/ Mixed MultiiLevel-Inverter topology(HMLI/MMLI). Each topology when used with renewable energy sources has its own features with corresponding advantages and disadvantages. This review is based on controlling methodologies, Total-Harmonic-Distortion (THD), construction complexity and components need for the respective topology. Multi-level-inverter (MLI) has the advantage of extinguishing the need of passive filtering at the grid side, and hence efficiency of the grid and cost minimization can be achieved.