Değişken Hızlı Rüzgâr Türbinlerinin Rüzgâr Sensörsüz Maksimum Güç İzleme Tabanlı Doğrusal Olmayan ve Tam Uyarlamalı Denetimi

Abstract

Abstract The aim of this project is to implement an analytical Maximum Power Tracking (MPT) based nonlinear and adaptive control of a Variable Speed Wind Turbine (VSWT) system without utilization of wind sensor and a priori knowledge of DHRT system parameters. When MPT based control of VSWT systems is the case, two important processes come into prominence. These are instantaneously determination and tracking of MPT point. It is necessary to use analytical methods to determine MGİ point accurately, but measurement of wind speed and apriori knowledge of turbine and/or generator parameters are required in all of these methods. Analytical methods proposed in literature are Tip Speed Ratio (TSR), Optimal Torque Control (OTC) and Power Signal Feedback (PSF) based MPT methods. TSR requires a wind sensor and exact model knowledge of the turbine. OTC and PSF require torque constant of the generator and exact model knowledge of the turbine. Torque constant varies with time depending on magnetic saturation in the steady state, and depending on imperfect decoupling in the transient. Wind sensor produces an output from a single measurement point, thus the mean value of wind speed effecting on blades of the turbine cannot be measured. Therefore, MPT is (not accurately but) approximately done by these methods in application. Besides, it should not be ignored that wind sensors used in VSWT systems decrease reliability. Instantaneous tracking of MPT point requires a closed loop control. Linear approaches such as ProportionalIntegral (PI) and linearization methods that system parameters are used in their designs constitute important drawbacks because of the reason mentioned above. With linear controllers, general control performance deteriorates and MPT point is tracked with a certain error. In control of nonlinear systems, the highest performance is achieved with nonlinear controllers. Consequently, an analytical MPT method based nonlinear and adaptive control of a VSWT system is carried out without utilization of wind sensor and priori knowledge of VSWT system parameters except for the turbine inertia, in this project. The inertia does not vary with time depending operation conditions, so its use is not a drawback. In the project, wind turbine emulator is obtained by driving an Induction Machine (IM) with rotor field oriented vector control. As generator, Permanent Magnet Synchronous Machine (PMSM) is used. In addition, a conventional VSWT system is implemented with TSR based MPT method and optimally designed PI controllers in order to compare the proposed system to the classical one. In case of a 10% error in wind speed measurement and a %10 perturbation in turbine parameters, %14.63 more energy is extracted by the proposed system compared to the classical one. Design of back to back converter, design of current and voltage measurement circuits, heatsink temperatures, DC link voltage spikes, and power factor at grid side meet the performance criterions given in the project proposal. This work has been financially supported by The Scientific and Technological Research Council of Turkey (TUBİTAK) in the context of 114E159 numbered research project. We would like to thank TUBITAK for funding this project work.