scholarly journals Nonlinear Optimal-Based Vibration Control of a Wind Turbine Tower Using Hybrid vs. Magnetorheological Tuned Vibration Absorber

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5145
Author(s):  
Paweł Martynowicz

This paper presents an implementation of a nonlinear optimal-based wind turbine tower vibration control method. An NREL 5.0 MW tower-nacelle model equipped with a hybrid tuned vibration absorber (HTVA) is analysed against the model equipped with a magnetorheological TVA (MRTVA). For control purposes, a 3 kN active actuator in parallel with a passive TVA is used in the HTVA system, while an MR damper is built in the MRTVA instead of a viscous damper, as in a standard TVA. All actuator force constraints are embedded in the implemented nonlinear control techniques. By employing the Pontryagin maximum principle, the nonlinear optimal HTVA control proposition was derived along with its simplified revisions to avoid a high computational load during real-time control. The advantage of HTVA over MRTVA in vibration attenuation is evident within the first tower bending frequency neighbourhood, with HTVA also requiring less working space. Using the appropriate optimisation fields enabled an 8-fold reduction of HTVA energy demand along with a (further) 29% reduction of its working space while maintaining a significant advantage of HTVA over the passive TVA. The obtained results are encouraging for the assumed mass ratio and actuator force limitations, proving the effectiveness and validity of the proposed approaches.

2016 ◽  
Vol 64 (2) ◽  
pp. 347-359 ◽  
Author(s):  
P. Martynowicz

Abstract Wind turbine tower dynamic stress is related to the fatigue wear and reliability of the whole wind turbine structure. This paper deals with the problem of tower vibration control using a specially designed and built laboratory model. The considered wind turbine tower-nacelle model consists of a vertically arranged stiff rod (representing the tower), and a system of steel plates (representing nacelle and turbine assemblies) fixed at its top. The horizontally aligned tuned vibration absorber (TVA) with magnetorheological (MR) damper is located also at the top of the rod (in nacelle system). Force excitation sources applied horizontally to the tower itself and to the nacelle were both considered. The MR damper real-time control algorithms, including ground hook control and its modification, sliding mode control, linear and nonlinear (cubic and square root) damping, and adaptive solutions are compared to the open-loop case with various constant MR damper input current values and system without MR TVA (i.e., MR TVA in “locked” state). Comprehensive experimental analyses and their results are presented.


2015 ◽  
Vol 23 (20) ◽  
pp. 3468-3489 ◽  
Author(s):  
Paweł Martynowicz

Wind turbine tower dynamic load is related to the fatigue and reliability of the structure. This paper deals with the problem of tower vibration control using specially designed and built numerical and laboratory model. The regarded wind turbine tower-nacelle model consists of vertically arranged stiff rod (representing the tower), and a stiff body fixed at its top representing nacelle assembly that is equipped with horizontally aligned tuned vibration absorber (TVA) with magnetorheological (MR) damper. To model tower-nacelle dynamics, Comsol Multiphysics finite element method environment was used. For time and frequency domain numerical analyses (including first and second bending modes of vibration) of system with TVA and MR damper models, MATLAB/Simulink environment was used with Comsol Multiphysics tower-nacelle model embedded. Force excitation sources applied horizontally to the nacelle, and to the tower itself were both considered. The MR damper real-time control algorithms, including ground hook control and its modification, sliding mode control, linear and nonlinear (cubic and square root) damping, and adaptive solutions are compared to the open-loop case with various constant MR damper input current values and system without MRTVA (i.e. MRTVA in ‘locked’ state). Comprehensive numerical analyses results are presented along with Vensys 82 full-scale tower-nacelle model validation. Finally, preliminary results of laboratory tests are included.


Author(s):  
P Bonello ◽  
K H Groves

An adaptive tuned vibration absorber (ATVA) can retune itself in response to a time-varying excitation frequency, enabling effective vibration attenuation over a range of frequencies. For a wide tuning range the ATVA is best realized through the use of a beam-like structure whose mechanical properties can be adapted through servo-actuation. This is readily achieved either by repositioning the beam supports (‘moveable-supports ATVA’) or by repositioning attached masses (‘moveable-masses ATVA’), with the former design being more commonly used, despite its relative constructional complexity. No research to date has addressed the fact that the effective mass of such devices varies as they are retuned, thereby causing a variation in their attenuation capacity. This article derives both the tuned frequency and effective mass characteristics of such ATVAs through a unified non-dimensional modal-based analysis that enables the designer to quantify the expected performance for any given application. The analysis reveals that the moveable-masses concept offers significantly superior vibration attenuation. Motivated by this analysis, a novel ATVA with actuator-incorporated moveable masses is proposed, which has the additional advantage of constructional simplicity. Experimental results from a demonstrator correlate reasonably well with the theory, and vibration control tests with logic-based feedback control demonstrate the efficacy of the device.


Author(s):  
Hamid Khakpour Nejadkhaki ◽  
John F. Hall ◽  
Minghui Zheng ◽  
Teng Wu

A platform for the engineering design, performance, and control of an adaptive wind turbine blade is presented. This environment includes a simulation model, integrative design tool, and control framework. The authors are currently developing a novel blade with an adaptive twist angle distribution (TAD). The TAD influences the aerodynamic loads and thus, system dynamics. The modeling platform facilitates the use of an integrative design tool that establishes the TAD in relation to wind speed. The outcome of this design enables the transformation of the TAD during operation. Still, a robust control method is required to realize the benefits of the adaptive TAD. Moreover, simulation of the TAD is computationally expensive. It also requires a unique approach for both partial and full-load operation. A framework is currently being developed to relate the TAD to the wind turbine and its components. Understanding the relationship between the TAD and the dynamic system is crucial in the establishment of real-time control. This capability is necessary to improve wind capture and reduce system loads. In the current state of development, the platform is capable of maximizing wind capture during partial-load operation. However, the control tasks related to Region 3 and load mitigation are more complex. Our framework will require high-fidelity modeling and reduced-order models that support real-time control. The paper outlines the components of this framework that is being developed. The proposed platform will facilitate expansion and the use of these required modeling techniques. A case study of a 20 kW system is presented based upon the partial-load operation. The study demonstrates how the platform is used to design and control the blade. A low-dimensional aerodynamic model characterizes the blade performance. This interacts with the simulation model to predict the power production. The design tool establishes actuator locations and stiffness properties required for the blade shape to achieve a range of TAD configurations. A supervisory control model is implemented and used to demonstrate how the simulation model blade performs in the case study.


2012 ◽  
Vol 594-597 ◽  
pp. 738-741 ◽  
Author(s):  
Yin Duan ◽  
Xing Hong Liu ◽  
Xiao Lin Chang

Main factors of the temperature control and crack prevention in arch dams are summarized. The Space-time Dynamic Control method in pipe cooling process and the Temperature Real-time Control and Decision Database System are introduced to help for temperature real-time control and rapid analysis. Successful application of these new techniques in the construction of Dagangshan arch dam indicates that the proposed method are of significant effectiveness on the temperature control and crack prevention, and have good application prospect in practical project.


Sign in / Sign up

Export Citation Format

Share Document