Multilevel inverters are suitable for high voltage and high power applications due to their ability to synthesize waveforms with better harmonic spectrum and reduced filter requirements. Three phase multilevel inverter fed induction motor drive is designed, employing Cascaded H-Bridge multilevel inverter. The inverter consists of series-connected halfbridge modules to generate the multilevel waveform and a simple H-bridge module, acting as a polarity generator. This topology, features many advantages when compared with the conventional multilevel inverters which include stability, simple control, reduced number of DC voltage sources and less devices count and also maintains a constant voltage at the output side irrespective of the load variations. The phase opposition disposition (POD) pulse-width modulation technique is employed to control the inverter. The inverter can then be connected to feed motor drives, which introduces a reduction in the THD of machine currents. The performance study of induction motor drive is carried out with MATLAB/SIMULINK. Hardware is implemented using TMS320F28335 digital signal processor.

Keywords : Multilevel Inverter, Control Schemes, Motor Drive.