Comparative study of diode clamp and H-bridge cascade multilevel inverter

Abstract

This paper presents a comparative study of diode clamp and H-bridge cascade multilevel inverter. Multilevel inverters have begun to demand higher power equipment, which now reaches the megawatt level. There are several topologies that are used in the industry today. They are the Diode-clamped Inverter (neutral-point clamped), Capacitor Clamped (flying capacitor), and H-Bridge Cascade Inverter. Multilevel inverters offer several advantages when compared to the conventional bridge inverter in terms of its ability to reduce voltage stress, lower switching frequency, small distortion and etc. In this paper concept of Diode Clamped and H-Bridge Cascade multilevel inverter are first reviewed. Subsequently control technique of multilevel inverter and circuit development are discussed. Finally simulation results of 3, 5, 7 and 9 level Diode Clamped and H-Bridge Cascade are discussed. For the result, according to the computer simulated result via PSIM software, the nine levels H-Bridge Cascade multilevel inverter has the lowest total harmonic distortion (THD) compared to the diode clamp multilevel inverter.