Comprehensive Review of Switched-Capacitor Boost Single-Source Nine-Level Inverters

Penetration of renewable sources into the grid demands new inverter configurations to improve the quality of voltage and current. In such application, multilevel inverters (MLIs) are booming due to their advantages of reduced harmonics and staircase output voltage pattern. Reduced switch and reduced source based topologies have been developed for different applications. However, switched-capacitor (SC) topologies are beneficial in reducing switch count as well as the source count while providing boosted output from a dc source. From 5-level, 7-level too much higher level SC type MLI topologies have been researched in recent years. In this work, 9-level topologies are extensively reviewed as it reduced the harmonics efficiently and on the other hand fewer components can be utilized to produce a required multilevel boosted output. A 9-level SC type MLI can produce two-time gain and four-times gain output efficiently. The 9-level MLIs with two-time gain, i.e., dual-boost SC MLI (SC-DMLI) and the other with four times gain capability, i.e., quadruple-boost SC MLI (SC-QMLI) are reviewed critically in this work. A comparison among these topologies is also illustrated. Simulation results of selected SC-DMLI and SC-QMLI are presented at the end for verification.