A Novel Contribution to Control a Wind Turbine System for Power Quality Improvement in Electrical Networks

Abstract

The typical control strategy for wind energy conversion systems (WECS) is the maximum power coefficient tracking method. However, this method limits the participation of wind turbines in power quality improvement in the network. To overcome this limitation, this paper presents, in the first step, a new methodology that derives the power coefficient that permits to expand the role of WECS based on doubly-fed induction generators, to load balancing and reactive power support to the grid. The proposed method allows the WECS to provide active power to the grid under better conditions compared to the typical control method. However, in case multilevel converters are used for grid connection of wind turbines, the application of the proposed method may imply the accentuation of the inherent problem of dc capacitor-voltage imbalance of these converters, leading to jeopardize their operation. For this reason, in the second step, a predictive control algorithm capable of simultaneously improving the power quality in power grids and ensuring reliable operation of the associated converter is proposed. The simulation and experimental results are presented.