Abstract:Only one wind field model loading the transmission tower or the tower-line system was investigated in the previous studies, while the influence of two different wind field models was not considered. In addition, only one sample of the wind speed random process was used in the past numerical simulations, and the multiple dynamic response statistical analysis should be carried out. In this paper, statistical analysis of the wind-induced dynamic response of single towers and the transmission tower-line system is … Show more
“…To achieve a greater reduction in the jitter, similar yaw system models as those used in the present study were investigated [33][34][35] by using the passive flutter suppression (PFS) method, with yaw vibration and low-speed buffeting discussed. The PFS technique was executed through methods, such as the structural stiffness adjustment design, friction torque matching, and driving-torque size adjustment, etc., and analyzed by using the finite element method.…”
Section: Focus On Different Knowledge Pointsmentioning
confidence: 99%
“…Whether it is a tower mode or cabin mode, there is no subdivision here, but it is arranged in numerical order. The comparison is based on the PFS method, using the finite element method in reference [34,35], and the additional motor drive design, using the iterative algorithm in the present study, by directly analyzing the eigenvalues in Formula ( 12). It can be seen that, compared with the PFS system based on the finite element analysis [35], the dynamic system with active control in this study generally reduces the frequency of each order modal, which means that the vibration becomes gentle and even tends to stabilize.…”
Section: Focus On Different Knowledge Pointsmentioning
confidence: 99%
“…In the traditional jitter control method, a performance balance method between worm gear self-locking and yaw braking mechanisms was also used to achieve limited LSJ suppression [32], which is a local and passive suppression method. The characteristics of this passive suppression method include stiffness adjustment design, finite element analysis method, and linear LSJ amplitude suppression based on the assumption of a constant yaw rate [33][34][35]. However, the active dynamic control method adopted in the present study not only achieves amplitude suppression, but also frequency suppression, and it can directly handle nonlinear systems, which has a positive significance for engineering applications.…”
Aiming at the nonlinear low-speed-jitter (LSJ) vibration suppression for a yaw system of a megawatt wind turbine, a kinematics mechanism of the yaw system is investigated from the perspective of tribology, and a kinematics model of the yaw system based on an equilibrium position is established. On the basis of the dynamic modeling of the yaw system, a nonlinear mathematical model of the LSJ system is deduced. Based on the two lead motors’ driving of the conventional yaw motion, an innovative design with a special installation of two auxiliary motors for yaw transmission is carried out, which is integrated with a matching centralized lubrication system (CLS). Based on open-loop proportional-derivative (PD) control and the iterative learning control methods of the time-varying continuous system, the stability control and jitter amplitude suppression of the yaw system are realized by using a combined driving torque provided by the lead and auxiliary gears. From the stability and convergence of the time-domain response and the convergence of the iterative error, the effectiveness of the iterative learning control method with the PD-based regulation is verified, and its advantages for engineering applications are shown based on the algorithm solver improvement. The feasibility of the physical realization and engineering application of the control methodology is verified by using controller-hardware-in-the-loop (C-HITL) simulation technology.
“…To achieve a greater reduction in the jitter, similar yaw system models as those used in the present study were investigated [33][34][35] by using the passive flutter suppression (PFS) method, with yaw vibration and low-speed buffeting discussed. The PFS technique was executed through methods, such as the structural stiffness adjustment design, friction torque matching, and driving-torque size adjustment, etc., and analyzed by using the finite element method.…”
Section: Focus On Different Knowledge Pointsmentioning
confidence: 99%
“…Whether it is a tower mode or cabin mode, there is no subdivision here, but it is arranged in numerical order. The comparison is based on the PFS method, using the finite element method in reference [34,35], and the additional motor drive design, using the iterative algorithm in the present study, by directly analyzing the eigenvalues in Formula ( 12). It can be seen that, compared with the PFS system based on the finite element analysis [35], the dynamic system with active control in this study generally reduces the frequency of each order modal, which means that the vibration becomes gentle and even tends to stabilize.…”
Section: Focus On Different Knowledge Pointsmentioning
confidence: 99%
“…In the traditional jitter control method, a performance balance method between worm gear self-locking and yaw braking mechanisms was also used to achieve limited LSJ suppression [32], which is a local and passive suppression method. The characteristics of this passive suppression method include stiffness adjustment design, finite element analysis method, and linear LSJ amplitude suppression based on the assumption of a constant yaw rate [33][34][35]. However, the active dynamic control method adopted in the present study not only achieves amplitude suppression, but also frequency suppression, and it can directly handle nonlinear systems, which has a positive significance for engineering applications.…”
Aiming at the nonlinear low-speed-jitter (LSJ) vibration suppression for a yaw system of a megawatt wind turbine, a kinematics mechanism of the yaw system is investigated from the perspective of tribology, and a kinematics model of the yaw system based on an equilibrium position is established. On the basis of the dynamic modeling of the yaw system, a nonlinear mathematical model of the LSJ system is deduced. Based on the two lead motors’ driving of the conventional yaw motion, an innovative design with a special installation of two auxiliary motors for yaw transmission is carried out, which is integrated with a matching centralized lubrication system (CLS). Based on open-loop proportional-derivative (PD) control and the iterative learning control methods of the time-varying continuous system, the stability control and jitter amplitude suppression of the yaw system are realized by using a combined driving torque provided by the lead and auxiliary gears. From the stability and convergence of the time-domain response and the convergence of the iterative error, the effectiveness of the iterative learning control method with the PD-based regulation is verified, and its advantages for engineering applications are shown based on the algorithm solver improvement. The feasibility of the physical realization and engineering application of the control methodology is verified by using controller-hardware-in-the-loop (C-HITL) simulation technology.
“…The works by Singh et al [2011a], Singh et al [2011b], Walls and Bendell [1987], Mignolet and Spanos [1989], Ho and Xie [1998], Billinton and Wangdee [2007] Sohn et al [2000], Fugate et al [2001], , , Owen et al [2001] Omenzetter andBrownjohn [2006], Carden and Brownjohn [2008], Zheng and Mita [2008], Drignei [2011], Bao et al [2013], Yao and Pakzad [2013], Goyal and Pabla [2016], Hu and Mahadevan [2017], Datteo et al [2018], Zhang et al [2018], Wang et al [2021], Samaras et al [1985] and Hu and Mahadevan [2017] employed Time Series models (i.e. AR, ARMA, among others) in the context of structural engineering and Time-dependent Reliability Analysis.…”
This chapter presents conceptual and computational comparisons between EOLE (Expansion Optimal Linear Estimation) and AR (Auto-Regressive) models to represent stochastic processes in the context of time-dependent reliability analysis. Even though expansion techniques, such as EOLE, are appropriate for problems where the properties of the stochastic process are explicitly known, such information is rarely available in practical situations. On the other hand, time series models, such as AR, are widely employed to represent stochastic processes from real time monitoring or available historical data. For this reason, here we compare EOLE and AR in the context of time-dependent reliability analysis. We first demonstrate how AR models can be calibrated to represent a given stochastic process with known properties. It is then demonstrated that similar results for time-dependent reliability can be obtained using the two approaches. This is an important contribution from both conceptual and practical reasons, since it demonstrates that existing AR models (and likely other types of time series models) can be directly employed for time-dependent reliability analysis, without the need to first obtain an equivalent EOLE model.
“…At the same time, the introduction of appropriate statistical parameters is helpful to analyze the distribution law of the wind-induced displacement response of structures and then take effective measures and methods to reduce the displacement vibration. Zhang et al [30] established the finite element model of the transmission tower-line system by ANSYS software, and they statistically analyzed the wind-induced dynamic response.…”
Wind tunnel tests and numerical simulations are the mainstream methods to study the wind-induced vibration of structures. However, few articles use statistical parameters to point out the differences and errors of these two research methods in exploring the wind-induced response of membrane structures. The displacement vibration of a saddle membrane structure under the action of wind load is studied by wind tunnel tests and numerical simulation, and statistical parameters (mean, range, skewness, and kurtosis) are introduced to analyze and compare the displacement data. The most unfavorable wind direction angle is 0° (arching direction). The error between experiment and simulation is less than 10%. The probability density curve has a good coincidence degree. Both the test and simulation show a certain skewed distribution, indicating that the wind-induced vibration of the membrane does not obey the Gaussian distribution. The displacement response obtained by the test has good stability, while the simulated displacement response has strong discreteness. The difference between the two research methods is quantitatively given by introducing statistical parameters, which is helpful to improve the shortcomings of wind tunnel tests and numerical simulations.
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