Performance improvement of single-phase PLLs under adverse grid conditions: An FIR filtering-based approach

Abstract With ever-increasing power quality problems in power systems, which are mainly attributable to the proliferation of nonlinear power electronics-based loads and also the high penetration of renewable energy sources in the utility grid, more advanced phase-locked loops (PLLs) for the synchronization of power converters and/or extraction of fundamental parameters of the grid voltage are needed. To this end, using a finite-impulse-response filter, which includes an arbitrary number of filter modules, is proposed in this paper. The design procedure for the proposed filter is explained in detail, and its effectiveness is investigated by applying it to a well-known single-phase PLL, the enhanced PLL (EPLL), and performing some comparative simulation and experimental tests. The obtained results demonstrate that the proposed filter can significantly enhance the filtering capability of the EPLL while preserving a fast dynamic behavior.