Integral sliding mode control for back-to-back converter of DFIG wind turbine system

Abstract

In this study, an integral sliding mode control approach for controlling the power electronics converters of a doubly-fed induction generator (DFIG) wind turbine system is presented. The power electronics interface consists of back-to-back converters. The rotor side converter regulates the active and reactive powers at the DFIG stator through controlling the stator currents. The stator current dynamics, with respect to the rotor voltages, is developed from the conventional equations of the DFIG model. In this control configuration, the knowledge about the rotor currents is not required, which reduces the use of the current measurement sensors. The grid side converter ensures constant dc-link voltage while transferring the power from the DFIG rotor to the grid. The proposed control approach uses a composition of sliding mode and integral parts to improve the overall performance and robustness against parametric variations and uncertainties. A lab-scale DFIG wind turbine system is used to investigate the proposed control approach efficiency under various operating conditions. The experimental results show the effectiveness of the proposed control approach in achieving control objectives to operate the DFIG wind turbine system.

Keywords

• asynchronous generators
• power generation control
• rotors
• power convertors
• variable structure systems
• stators
• wind turbines
• integral sliding mode control
• power electronics converters
• induction generator wind turbine system
• power electronics interface
• active powers
• reactive powers
• dfig stator
• stator currents
• stator current dynamics
• rotor voltages
• dfig model
• control configuration
• rotor currents
• current measurement sensors
• dfig rotor
• lab-scale dfig wind turbine system
• control approach efficiency
• control objectives