DYNAMIC MODELING, CONTROL AND ADAPTIVE ENVELOPE PROTECTION SYSTEM FOR HORIZONTAL AXIS WIND TURBINES


Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Havacılık ve Uzay Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2018

Öğrenci: MUSTAFA ŞAHİN

Danışman: İLKAY YAVRUCUK

Özet:

In this thesis study, a wind turbine envelope protection system is introduced to protect turbines throughout the below and above rated regions. The proposed protection system, which is based on a neural network, adapts to various turbines and operational conditions. It can keep the turbine within pre-defined envelope limits whenever a safe operation is about to be violated. The avoidance is realized by control limiting technique applied to the blade pitch controller output, thereby adjusting the blade pitch angle. To achieve the purpose, a horizontal axis wind turbine (HAWT) dynamic (simulation) model based on Blade Element Momentum (BEM) theory is developed using MATLAB and Simulink programs. It is named as MS (Mustafa Sahin) Bladed simulation model. The MS Bladed model includes important aerodynamic corrections and particular coordinate systems etc. for a more realistic turbine behavior. It is validated using experimental data or program/model performance predictions of various turbines belong to National Renewable Energy Laboratory, or NREL. Eventually, NREL 5 MW wind turbine is adopted in the MS Bladed model. Baseline controllers such as generator torque and collective blade pitch controllers are designed for NREL 5MW turbine, and then their simulations are evaluated. Afterward, the proposed protection system is designed and added on to the controlled MS Bladed model for NREL 5 MW turbine. Thrust force is selected as the pre-defined envelope limit. Simulations under normal turbulent winds with different mean values have shown that the newly proposed system shows a promising capability to keep the 5 MW turbine within the pre-defined thrust limit throughout the below and above rated regions. In this thesis study, three example cases under normal turbulent winds with mean values of 8, 11 and 15 m/s are given to show the effectivity of the proposed algorithm.