LPV controllers for a DFIG in a microgrid under unbalanced conditions

Abstract

State-space controllers have been central to modern control theory and are often preferred over classical controllers such as PI and lag-lead controllers. This is because they offer flexibility in design, such as being to simultaneously incorporate performance and robustness requirements, and have a solid mathematical foundation. Recently, doubly-fed induction generators (DFIGs) for wind turbines have been modeled as linear parameter varying (LPV) systems, a special class of time-varying linear state-space systems, for which LPV state-space controllers can be designed. The LPV controllers have been introduced for DFIG mainly because of their novelty and that they can offer the typical advantages that come with state-space controllers. In this paper, LPV controllers have been designed using linear matrix inequality (LMI) techniques and their performance is studied via simulation on a DFIG connected to a microgrid. The study shows that LPV controller for DFIG can significantly improve system performance under unbalanced conditions.