Abstract
Due to rapid development of High-power Electronics Technology, Flexible Alternating Current Transmission System (FACTS), based on High-Power Electronic Circuits, can offer an opportunity to enhance controllability, stability, and power transfer capability of the existing system. It has becomes an important topic in the Smart Grid roadmap world wild. Among all FACTS, Unified Power Flow Controllers (UPFCs) seem to be the most comprehensive and provide the greatest flexibility with multiple control functions simultaneously. The aim of this thesis is to develop hardware implementations of a small laboratory-scale UPFCs. The rating of this three-phase UPFCs is 110 V, and 1kVA. The power circuit consists of a shunt voltage sourced converter (VSC) and a series VSC. By proper switches reconfigurations, this UPFC can also provide shunt compensations or series compensations independently. The dynamical model of the UPFC under the synchronous reference frame will be described first. The inner/outer two-loop decoupled control strategy is studied later. The inner loop control is designed for the VSI current command tracking while the outer loop control is designed different commands following. The proposed control configuration has been validated under Simulink simulations and hardware laboratory implementations. Experimental works on various operating conditions have been conducted to verify the effectiveness of the proposed control strategy.