A New Modulation Index Control (MIC) Technique for Reducing THD for Photovoltaic Applications

This paper proposes a new technique to enhance the inverter output wave quality by introducing a new technique that optimizes the inverter modulation index and it is the so-called Modulation Index Controller (MIC). Therefore, the MIC technique ensures optimum dc-link voltage which results in modulating the inverter output Total Harmonic Distortion (THD). In addition, extracting the maximum PV power by controlling directly the PV load without controlling the duty cycle of the conventional DC-DC converters. This paper presents a three-level Neutral-Point-Clamped (3L-NPC) multilevel
inverter interfaced Photovoltaic energy conversion system to generate output voltage with low total harmonic distortion via Buck-boost converter which regulates the DC-Link voltage by increasing the modulation index to reduce Total Harmonic Distortion (THD). The system is modeled using MATLAB/SIMULINK. Moreover, the system has been experienced when using MIC technique and without using MIC technique. The simulation and experimental results proved that the overall proposed system including Direct Power MPPT and MIC control decline the total harmonic distortion and enhancing the overall system efficiency.