Comparative experimental evaluation of three-wire SAPF control strategies for power quality improvement

Filtering plays a vital role in maintaining power quality in three-phase systems, and Shunt Active Power Filters (SAPF) have emerged as the preferred solution in modern applications. In order to compare the performance outcomes of PI, PR, and PI-PR controllers, a laboratory implementation of Direct Current Control (DCC) will be presented in this study. Traditional PI control methods have limitations in eliminating high harmonics in line currents and harmonics at the DC link of an SAPF. In contrast, the PR control method offers significant advantages by nullifying DC link harmonics and providing superior performance and accuracy compared to conventional control and DC link voltage control methods. This improvement is evident in terms of power quality enhancement and cost-effectiveness for SAPF systems since it lowers operating costs, enhances voltage stability, and decreases harmonic distortion. Furthermore, a proposed PR-PI strategy introduces a modernized control structure with an enhanced capability to compensate for low-order harmonics. The suggested control method demonstrates the ability to maintain a low Total Harmonic Distortion (THD) in the injected current, even when abnormal grid conditions arise, in contrast to PI and PR controllers. Additionally, it delivers reduced overshoot and settling time, along with a smaller steady-state error. The effectiveness of these three control methods, DCCPI, DCC-PR, and DCC-PI-PR, was demonstrated through simulation and experimental results, emphasizing their respective performances in improving power quality.