Inertia Evaluation and Optimal Design for PMSG-Based Wind Turbines With df/dt Control

Abstract

The df/dt control is widely used for permanent magnet synchronous generator (PMSG)-based wind turbines (WTs) to achieve inertial response. However, existing studies have only used df/dt control coefficients to characterize the inertia of WTs, which leads to inaccurate inertia evaluation and unsatisfactory design of control parameters. To deal with it, this article presents an inertia evaluation and optimal design of PMSG-based WTs, by considering the multiloop control dynamics. Firstly, the magnitude-phase motion model is established and the equivalent inertia in the form of a transfer function is derived. Then, the influence of multiloop controllers and wind speed on equivalent inertia is explored, and the critical factors are revealed. Furthermore, considering the inertia support requirements and the stable operation of the WTs, the inertia control parameters are optimally designed. Finally, the analysis and design are validated by experiments.