Seven Level Modified Cascaded Inverter for Induction Motor Drive Applications

Abstract

In this paper, an H-bridge inverter topology with reduced switch count technique is introduced. This technique reduces the number of controlled switches used in conventional multilevel inverter. To establish a single phase system, the proposed multilevel inverter requires one H-bridge and a multi conversion cell. A multi conversion cell consists of three equal voltage sources with three controlled switches and three diodes. In conventional method, twelve controlled switches are used to obtain seven levels. Due to involvement of twelve switches the harmonics, switching losses, cost and total harmonic distortion are increased. This proposed topology also increases the level to seven with only seven controlled switches. It dramatically reduces the complexity of control circuit, cost, lower order harmonics and thus effectively reduces total harmonic distortion.

Keywords: Cascaded Multilevel Inverter, H-bridge Inverter, Total Harmonic Distortion, Sinusoidal Pulse Width Modulation, Insulated Gate Bipolar Transistor