Performance Investigation of Different Modulation Schemes for an 11-level NPC Inverter Fed Induction Motor Drive

The neutral point clamped (NPC) inverter is the most prevalent topology among all the multilevel converter topologies because of its good power quality and high efficiency. For past few decades, NPC inverter is popularly being used in industrial motor drive applications. The modulation strategies have a significant impact on the power efficiency of inverter fed motor drive systems. This paper presents a comparative study on the performances of a three phase 11-level NPC fed induction motor for several common pulse width modulation (PWM) based multilevel converter modulation schemes using MATLAB/ Simulink. This study includes the results of line voltage and current profiles of an inverter, total harmonic distortion characteristics, power loss performance of NPC as well as induction motor’s torque and speed profiles. The main aim of this paper is to explore different recently developed modulation strategies to determine a suitable one to ensure high efficiency of an NPC converter fed induction motor drive system.