Control of Seven Level Cascaded H-Bridge Inverter by Hybrid SPWM Technique

Multilevel inverter technology has emerged recently as a very important alternative in the area of high power energy control. Number of topologies have been introduced and widely used in drive applications. Among these topologies, the cascaded H-Bridge inverter is used in this paper because of its advantages over other topologies. Different control techniques are available to control these inverter such as selective harmonics elimination (SHE), space vector modulation (SVM), sinusoidal pulse width modulation (SPWM), etc. The SPWM control techniques is categorized as phase shifted SPWM technique and level shifted SPWM such as phase opposition disposition(POD), in phase disposition (IPD), alternate phase opposition disposition (A POD) techniques. This paper presents a control of seven level cascaded H-Bridge inverter by Hybrid SPWM (Combination of phase shifted and level shifted) technique. In this paper special attention is given to the THD at the output of the inverter using hybrid SPWM technique. Simulation results using PSIM software and its hardware implementation and results are presented and discussed together.