Abstract
The rapid proliferation of grid-connected wind energy conversion systems (WECS) has exacerbated power quality issues, predominantly harmonic distortion induced by non-linear switching in power electronic converters. To address this challenge and ensure strict adherence to grid compliance codes such as IEEE-519, this paper proposes an optimized control strategy for a three-phase Shunt Active Power Filter (SAPF) integrated at the Point of Common Coupling (PCC) of a Doubly Fed Induction Generator (DFIG)-based wind turbine system. The proposed scheme combines an enhanced Synchronous Reference Frame (SRF) extraction method with an adaptive Fractional-Order Proportional-Integral (FOPI) current controller whose gains are dynamically tuned via an improved Particle Swarm Optimization (IPSO) algorithm. A comprehensive simulation framework was developed in MATLAB/Simulink and validated using a hardware-in-the-loop (HIL) experimental setup. Under varying wind velocities and fluctuating non-linear load conditions, the uncompensated system exhibited a total harmonic distortion (THD) of 12.84% in grid currents. Implementation of the proposed IPSO-FOPI-driven SAPF dramatically suppressed the THD to 1.76%, while concurrently stabilizing the DC-link voltage with minimal overshoot and restoring the system displacement power factor to 0.998. The comparative analysis confirms the superior dynamic tracking, robustness, and harmonic elimination capabilities of the proposed architecture over conventional PI and standard resonant control topologies.
