Analysis and Simulation of Three Phase Modified Hybrid Cascaded Multilevel Inverter for Induction Motor

Abstract

The power converters are used to modify one form of electrical energy to another. The class of power converter that produce AC power from DC power is known as inverter. Due to high THD and losses, the conventional two level inverters are not suitable for high power applications. So multilevel inverters have drawn tremendous importance in power industries. This dissertation presents different Cascaded H-Bridge inverters. A single phase 5-levels hybrid MLI is implemented by incorporating half-bridge and full-bridge inverter. It is further extended to implement single phase 7 levels hybrid MLI. This also presents single DC source seven level CHB inverter. It uses single DC input while changing other DC source with a capacitor as energy storing element. Then a three phase modified hybrid cascaded multilevel inverter is suggested incorporating standard three leg inverter with H-bridge cells. The switching scheme with multicarrier level shifted SPWM is implemented to produce different possible levels. This MLI is implemented to run an induction motor load. In addition, a second order LC filter is designed to reduce the THD below 5% as per standard IEEE-519. Simulations have been performed using MATLAB to study different topologies, voltage levels, modulation scheme and THD. Finally, the possibilities of future works are addressed.