An Efficient Modulation Strategy for Modular Multilevel Cascaded Inverter Used in Solar PV Fed Induction Motor Drive Systems

In this research work, a new modulation technique is proposed to control the switching of a 3-phase modular multilevel converter (MMC) based solar photovoltaic (PV) fed induction motor (IM) drive system. Multilevel inverters (MLIs) are gaining popularity in the industry as medium-voltage and high-power electronic power conversion solutions. Different multilevel inverter topologies have grown in prominence in recent years, owing to a variety of advantages, particularly in induction motor driving systems. Inverter switching strategies are critical for improving power quality. In this paper, a new switching method for a 5-level MMC is proposed that ensures high power quality, improves speed and torque performance, and reduces total harmonic distortion (THD) in the voltage and current waveforms of the stator of a PV-based IM. The practicality of this modulation method is demonstrated by comparing its performance to that of several existing popular switching strategies. The design, implementation, and comparisons are done by using MATLAB/Simulink simulation. A laboratory-scale prototype is developed and tested to evaluate the performance of the proposed switching technique.