Browsing by Author "Rapporteur/ CHEBABHI Ali"

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    Control of parallel voltage source inverters, circulating current elimination and output power quality improvement
    (2025) Redaoui Mohammed; Ibrir Tarek; Rapporteur/ CHEBABHI Ali
    This thesis presents a comprehensive control strategy for parallel three-phase inverters operating in standalone mode, specifically addressing the critical issue of circulating current elimination under challenging operating conditions. The research focuses on developing robust control methods to manage circulating currents that arise between parallel inverters when subjected to unbalanced output inductive filters and unequal output current demands. The primary challenge addressed in this work stems from the inherent mismatch in output inductances and unequal output current demands, which create differential voltage drops across parallel inverter branches. These mismatches lead to unwanted circulating currents that reduce system efficiency, increase component stress, and compromise the overall reliability of the parallel inverter configuration. A novel control method was developed and implemented to actively suppress circulating currents while maintaining balanced three-phase output voltages and currents. The proposed control scheme incorporates advanced super twisting output current regulations and modified pulse-width modulation (PWM) patterns based on inverter output voltage reference adjustments using the regulation of the circulating current with zero via PI controller that account for filter imbalances and unequal output current demands. Extensive simulation studies were conducted to evaluate the effectiveness of the proposed control method. The results demonstrate significant reduction in circulating currents and improvement in parallel inverter’s output current quality under various operating scenarios, including unbalanced output inductive filters and unequal output current demands. The control system successfully maintains proper output currents among parallel inverters while ensuring stable operation and improved power quality. This work provides valuable insights for the design and control of parallel inverter systems in standalone applications, particularly in renewable energy systems, uninterruptible power supplies, and distributed generation systems where reliable operation under varying conditions is essential.