Collaborative Design of Multiloop Controllers for DFIG-Based Wind Turbines to Optimize Inertia Characteristics

Controller parameter optimization-based inertia provision methods for wind turbines (WTs) have received much attention, due to their economy and convenience. However, the existing methods fail to consider the effect of multiple controllers on the magnitude-phase characteristics of inertia, which may cause a short support time of WT's inertia response and even deteriorate the system frequency dynamics. To cope with it, this article proposes a collaborative design of multiloop controllers for doubly-fed induction generator (DFIG)-based WTs to optimize inertia characteristics. First, the magnitude-phase characteristics of WT's inertia and their effect on system frequency are analyzed. Then, based on the Sobol' sensitivity analysis method, the dominant influences affecting the magnitude and phase of WTs’ inertia are revealed, respectively. On this basis, a collaborative design method of multiloop controllers is proposed from the perspective of the magnitude-phase characteristics optimization of WT's inertia, which can support system frequency effectively while satisfying constraints of stability as well as rotor kinetic energy. Finally, the analysis and the proposed design method are verified by hardware-in-loop experiments.