Power-current controller based sliding mode control for DFIG-wind energy conversion system

Abstract

This study presents an overall sliding mode control scheme for stator power-current control, grid power-current control and dc-link voltage regulation to operate a doubly-fed induction generator (DFIG) based wind energy conversion system. At the generator rotor side, the stator power control is achieved through controlling the rotor currents. The rotor current state model is carried out from the stator and the rotor equations of the generator under the condition of stator voltage alignment. At the grid side, a cascade control loop is applied for the dc-link voltage regulation and the power transfer using grid and dc-link modelling. The structure of the sliding mode control law, combination of compensating, sliding and integral terms, enhances the tracking performance and the robustness to uncertainties. The proposed control strategy is validated using an experimental DFIG wind turbine system and the results are provided to demonstrate the capabilities of the proposed control system in tracking and control under different operating conditions and robustness to uncertainties.