Phase-locked loop tuning with step-wise inertia control for frequency support of PMSG wind turbine systems

The rapid global increase in wind turbine (WT) penetration necessitates compliance with grid codes for effective frequency control and stability. This study focuses on the integration of a phase-locked loop (PLL) tuning method with a step-wise inertia control to support frequency regulation in Permanent Manet Synchronous Generator (PMSG) WT systems. The proposed approach addresses the challenge of providing inertia support through power electronics in type-3 WT systems, which lack inherent inertia due to their decoupling from the grid. By modeling the dynamic inertia of the PMSG WT system and optimizing the PLL control, the study aims to enhance grid frequency response during disturbances. The research involves simulation and experimental validations to show the effectiveness of the coordinated control strategy, focusing on performance metrics such as the minimum grid frequency F n a d i r and the rate of change of frequency (ROCOF). The findings highlight the importance of PLL bandwidth selection in balancing inertia emulation and frequency tracking accuracy, proposing guidelines for optimal PLL design to improve WT system inertia and overall grid stability.