Complex-Valued Sliding-Mode Control for DFIG Synchronization to Non-Ideal Grids

• Published in: IFAC-PapersOnLine Vol. 56; no. 2; pp. 2746 - 2752
• Main Authors: Susperregui, Ana, Martínez, M. Itsaso, Tapia-Otaegui, Gerardo, Solsona, Jorge A., Jorge, Sebastián Gómez, Busada, Claudio A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2023
• Subjects: Complex variables; harmonics; induction generators; renewable energy systems; robustness; sliding-mode control; synchronization; voltage imbalances; wind; sliding-mode control; harmonics; robustness; induction generators; synchronization; Complex variables; renewable energy systems; voltage imbalances; wind
• ISSN: 2405-8963; 2405-8963
• DOI: 10.1016/j.ifacol.2023.10.1372

Even if the electrical grid is subject to constrained disturbances, doubly-fed induction generator (DFIG)-based wind turbines should be able to synchronize their stator voltage with that of the grid to ensure a smooth connection to the electric power system. In order to face the synchronization task under simultaneously unbalanced and harmonically distorted grid voltages, a complex-valued sliding-mode control (SMC) algorithm, naturally chatter-free and phase-locked loop (PLL)-independent, is proposed. By accomplishing a stationary reference frame-based design, decomposition into positive- and negative-sequences and harmonic components is not required. The finite-time convergence of such algorithm is analytically demonstrated when subject to both parametric and unmodeled uncertainties, as well as disturbances. Simulation over a 2-MW DFIG model has been carried out in order to validate the performance and robustness of the suggested control structure under unbalanced and harmonically distorted grid voltage, variable speed wind profile, substantial parameter deviations and grid frequency variation.