Adaptive RSC Control through Rotor Currents Dynamics Linearization for WT Coupled DFIG

This paper deals with an adaptive rotor side converter (RSC) control through linearization of rotor currents dynamics for wind turbine (WT) coupled doubly fed induction generator (DFIG). The WT coupled DFIG is interfaced to the grid. The control comprises of feedback control and unique state observer. The dynamics of rotor currents in synchronously rotating dq reference frame, are linearized to obtain the feedback control design. The unique state observer is designed to estimate the system unique states. Moreover, these states are established to include the disturbances due to sudden change in wind speeds, coupling terms between d and q axes and system nonlinearities. The adaptive RSC control is framed to effectively obtain unity power factor in the stator and also to acquire maximum power from the WT. In addition, the control of grid side converter is designed to regulate the DC link voltage and to compensate the unbalanced and nonlinear loads. The simulated performance of the system is presented for varying wind speeds and nonlinear unbalanced loads to show the effectiveness of the control algorithms. Moreover, a prototype is developed in the laboratory to validate its steady state and dynamic behaviors.