A single-phase unified power quality conditioner with an enhanced repetitive controller
This paper proposes a robust and flexible control strategy for a single-phase unified power quality conditioner (S-UPQC) to solve the power quality problem due to the distorted input supply voltage and the nonlinear load. In order to enhance the performance of the series and shunt active power filters (APFs) in S-UPQC, an advanced current and voltage control schemes are introduced based on the modified repetitive controller (RCs) connected with a proportional-integral (PI) controller. Unlike the conventional control scheme for the series and shunt APFs, the proposed scheme is implemented without any harmonic extractor. Furthermore, the dynamic performance is improved significantly due to the reduced delay time of the RC, and the computation time is also reduced. The effectiveness of the proposed control schemes for the S-UPQC is validated through simulation.