Study of Switched Inductor Based Z-Source Cascaded H-Bridge Multilevel Inverter

P. Satheesh Kumar, Dr. S. P. Natarajan, Dr. Alamelu Nachiappan, Dr. B. Shanthi

This paper proposes a Switched Inductor-Z-Source Cascaded H-Bridge Multilevel Inverter (SL-ZS-CHB-MLI). This proposed topology has wide applications in ac- ac, dc- ac, dc- dc, dc- ac power conversion. This topology is made up of numerous basic units. The number of basic unit required is based on the formula (n-1)/2, where n is the number of levels. Each basic unit in the proposed SL-ZS-CHB-MLI topology are developed by a Z-Source (ZS) network comprising switched inductor cells, and a H-Bridge cell. The proposed topology has high output voltage boosting capability due to the presence of switched inductor cells, which further reduces ripple contents in the input current. It is also having the advantage of lower voltage stress across capacitors. The proposed topology exhibits high output voltage boosting capability with lower THD. The principle of operation of shoot through and non-shoot through states of the SL-ZS-CHB-MLI is elucidated in detail with equivalent circuit diagrams. Capacitor voltages for each basic unit in the 11-level proposed topology have been presented. The Harmonic analysis of the proposed topology for 5, 7, 9 and 11 level output voltages is presented with simulated results obtained from MATLAB software.