A novel negative feedback phase locked loop-based reference current generation technique for shunt active power filter.

• A novel improved negative feedback PLL (NFPLL)-modified synchronous reference frame (MSRF)-based control circuit is proposed for shunt active power filter (SAPF). • The performance of the proposed NFPLL-MSRF scheme under different source and load conditions has been deeply analyzed through a series of simulation-based experiments. • A detailed performance comparison of the proposed NFPLL-MSRF scheme with conventional approaches is presented. • The performance of the proposed control technique is validated using OPAL-RT 4510 real-time digital simulator platform. The use of nonlinear devices introduces current and voltage harmonics into power distribution networks. The presence of harmonics, an undesirable power quality issue, causes transformer overheating, malfunctioning of sensitive loads, power losses, and significantly reduced distribution system efficiency. Therefore, harmonics mitigation in power systems has become absolutely essential and is widely addressed, utilizing shunt active power filters (SAPFs) around the globe. The performance of SAPF in generating adequate compensating current depends on the working of three control loops used for the purpose of reference current generation, dc-link voltage control, and switching pulse generation. The existing approaches for reference current generation suffer from inherent complexity and the inability to extract positive sequence signals required for obtaining synchronizing angle during source disturbance conditions. Therefore, this paper proposes a novel negative feedback phase-locked loop-based modified synchronous reference frame technique to overcome the drawback of the existing approaches. The effectiveness of the proposed approach is investigated under ideal and non-ideal grid voltage conditions with different load perturbations. The proposed control strategy is first tested using a number of simulation-based experiments and, thereafter, validated using OPAL-RT 4510 real-time digital simulator. Compared to other existing approaches, the proposed technique has offered improved results in terms of reduced total harmonics distortion. [ABSTRACT FROM AUTHOR]