Fuzzy Logic Controller-Based Non-Isolated Single-Phase Half-Bridge Unified Power Quality Conditioner for Ripple Elimination

The integration of renewable energy sources and sensitive electronic loads into power systems necessitates reliable solutions for enhancing power quality. The versatile Unified Power Quality Conditioner (UPQC) addresses issues such as voltage dips, spikes, flicker, harmonics, and interruptions. However, UPQC performance is hampered by direct current (DC) voltage ripples, especially in non-isolated single-phase half-bridge systems. This study introduces a suppression technique to mitigate the effects of DC voltage ripple and examines its impact on circuit efficiency. Part one explores the causes of DC voltage ripple in non-isolated single-phase half-bridge UPQCs, including harmonic distortions, imbalanced load conditions, and power electronic component characteristics. Ripple influences the DC-link voltage, leading to unstable UPQC operation, reduced compensation performance, and increased losses. To address these challenges, a comprehensive suppression strategy is developed, combining robust control algorithms with enhanced filtering and optimized passive components. This method actively reduces DC voltage ripple, ensuring stability and consistent performance under varying conditions. Extensive computational modeling and experimental validation demonstrate significant reductions in DC voltage ripple and improved current and voltage waveforms at the point of common coupling (PCC). The proposed suppression technique enhances UPQC adaptability, ensuring stable and reliable operation even under extreme conditions.