Modified Switching PWM Method to Reduce the THD and Power Loss of NPC Inverters

Minimizing total harmonic distortion (THD) and mitigating switching power loss because of high frequency switching in a solar photovoltaic (PV) fed multilevel inverter (MLI) based grid-tied system is always considered as a research challenge. The THD and power loss of MLI determine the power quality of MLI which are influenced by the pulse width modulation (PWM) method. Yet, conventional PWM techniques for multilevel inverters (MLI) encounter challenges concerning increased total harmonic distortion (THD) and power loss issues. This research endeavor introduces a novel level shifted carrier-based PWM approach to mitigate total harmonic distortion (THD) and minimize power loss in neutral point clamped (NPC) inverters. Apart from these, thermal analysis results for the proposed PWM method are provided in this work. The proposed PWM method is tested in an NPC inverter-based grid-tied PV system. The system is modeled and simulated in MATLAB/Simulink and PLECS software platforms as well as reduced scale experimental test is also conducted to validate the simulation analysis.