A Novel PWM Strategy with an Efficient Closed Loop Control Technique for Grid-Connected Three Level NPC Converter

This paper embodies a novel Pulse Width Modulation (PWM) strategy with an advanced closed-loop control technique for grid-connected three-level Neutral Point Clamped (NPC) converters. The proposed method efficiently adjusts the power factor to meet grid demands, supporting unity, lagging, or leading power factors. It achieves significant reductions in voltage and current Total Harmonic Distortion (THD), with voltage THD at 20.92% and current THD at 1.64%, both complying with the Institute of Electrical and Electronics Engineers (IEEE)-519 standard. These improvements are due to modifications in the modulating signal and carrier waveform. The method also demonstrates stable THD performance across varying switching frequencies and modulation indices. Simulation results validate the proposed approach, showing better THD performance than conventional PWM techniques such as Sinusoidal PWM (SPWM), Third Harmonic PWM (THPWM), Triangular PWM (TRPWM), and Bus-Clamping PWM (BCPWM). This work demonstrates the potential of the proposed method to enhance the performance of NPC converters in grid-connected systems, ensuring improved power quality and robust control.