A Comprehensive Survey on Harmonic Elimination in Multilevel Inverters Using Optimization Techniques for Power Quality Improvement

Abstract

Background: Renewable energy sources offer sustainable solutions, but the conversion of DC energy into AC energy, commonly used in electrical devices necessitates inverters. Multilevel inverters have gained favor over conventional two-level inverters in high-power, mediumvoltage industrial and renewable energy applications due to their high switching frequency capabilities and ability to produce low-harmonic distortion voltage, ensuring superior power quality. Aims: This study focuses on addressing the adverse effects of harmonics in electrical systems and investigates methods to eliminate them in multilevel inverters. Methods: This study summarized current research works on traditional and advanced harmonic removal optimization strategies in multilevel inverters to highlight the limitations, objectives, THD%, and summary of existing works. Moreover, this study applies selective harmonic elimination techniques in 7-level and 15-level inverters using PSO and IPSO optimization algorithms to minimize THD and enhance inverter performance. Results: The study summarizes current research on harmonic removal strategies in multilevel inverters, revealing the prevalent use of MATLAB/Simulink in research endeavors. Various modulation and optimization techniques have been explored to achieve low THD in the output waveform, aligning with IEEE 519 standards for power system harmonic distortion. Furthermore, the comparative analysis part highlights increasing THD improvement with higher inverter levels. The 15-level inverter stands out, achieving 6.75% THD with PSO and 4.12% with improved PSO, meeting IEEE 519's THD limit. Conclusion: The study underscores the importance of ongoing research in this field to advance harmonic reduction strategies, making multilevel inverters even more attractive for a wide range of applications.