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

A. SUSPERREGUI; M. ITSASO MARTÍNEZ; G. TAPIA-OTAEGUI; J. SOLSONA; S. GÓMEZ JORGE; C. BUSADA

Congreso; 22nd. IFAC World Congress; 2023

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 phaselocked loop (PLL)-independent, is proposed. By accomplishing a stationary reference framebased 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.