A Multilevel Inverter for Grid-Connected Photovoltaic Systems using Improved Moth Flame Optimization

Abstract

In recent days, Renewable energy is rapidly growing, with solar energy being the most researched due to its sustainability, efficiency, and global adoption. Traditional approaches for grid-connected Photovoltaic (PV) systems have faced several challenges which include high Total Harmonic Distortion (THD) and low efficiency. Therefore, this research proposes five level Neutral Point Clamped (NPC)inverter optimized by Improved Moth Flame Optimization (IMFO) for grid connected PV systems. Initially, PV generator converts the absorbed sunlight into electrical energy where, multiple solar cells are connected in series and parallel to generate required DC power. Next, a Direct Current to Direct Current buck converter (DC-DC) with Incremental Conductance Maximum Power Point Tracking (IC-MPPT) method is employed where, IC MPPT is used for extracting the maximum power from PV generator and DC-DC buck converter for stabilising varying DC voltage. Further, Proportional Integral (PI) controller is employed for regulating DC voltage and controls Alternating Current (AC) power injection into grid by adjusting inverter switching patterns. To enhance the performance of PI, a IMFO is employed which optimized the parameters of PI controller. This obtained stable DC power is converted into AC power by the five level NPC inverter. Finally, an Inductor Capacitor (LC) filter is employed which filters the remaining harmonics and pure AC power is integrated in to grid. The proposed IMFO achieved better results in terms of K_p (0.0250) and K_i (0.0085) and THD (0.25) which attained very low THD when compared to existing Genetic Algorithm (GA).