Conventional and adaptive second-order sliding mode control of a wind energy conversion system

Abstract

In this chapter, an adaptive second-order sliding mode technique is exploited to optimise the efficiency of a variable-speed wind turbine. A revisited form of a recently proposed adaptation algorithm is proposed to deal with the characteristics and control requirements of the wind energy conversion system (WECS), particularly model uncertainties and fastly varying disturbances due to gusty wind effects. The revisited algorithm enhances the reactivity of the adaptation strategy against fast varying uncertainties. The proposed approach is successfully used to control a Doubly-Fed Induction Generator (DFIG) based wind turbine topology proving its suitability for this application area. The design and convergence analysis of the adaptive controller are developed considering a reduced-order model of the DFIG. However, the performance of the closed-loop system are extensively assessed through computer simulations made also over a full-order realistic model of the WECS under study.