Integrated Power Control Analysis of DFIG Wind Turbines Considering Structural Flexibility

2011 ◽  
Author(s):  
Qiong-zhong Chen ◽  
Olivier Bru¨ls
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Simulation Software ◽  
Prototype Model ◽  
Structural Flexibility ◽  
Control Analysis ◽  
Lumped Mass ◽  
Power Extraction ◽  
Flexible Multibody ◽  
And Control

Doubly-fed induction generators (DFIGs) are commonly used in variable-speed wind turbines for more power extraction. Unlike previous research on DFIG wind turbines, which typically uses an equivalent lumped mass model of the drive train dynamics, but does not include detailed aerodynamic/mechanical representations, this paper investigates on the modelling and control of DFIG wind turbines by following a systematic approach based on a flexible multibody simulation software. The wind turbine structure, generator and control subsystem models are modularly developed for the S4WT package (Samcef for Wind Turbines), which is a user interface for the analysis of wind turbines. An extension of the finite element method is available in the flexible multibody dynamics solver, for the representation of the non-mechanical components, i.e., the generator and the control system, so that the coupled mechatronic system is simulated in a strongly coupled way. This integrated approach is less intricate and more robust than approaches based on an external DLL or co-simulation methods. The objective of this work is to analyze the control-generator-structure interactions in a wind turbine system. The power optimization control is elaborated in detail. A 2MW DFIG wind turbine prototype model is presented for validation. Dynamic analysis including the control effects and the influence of the structural flexibility is provided in an overall range.

scholarly journals Virtual Prototyping of a Low-Height Lifting System for Offshore Wind Turbine Installation

2020 ◽  
Author(s):  
Jiafeng Xu ◽  
Behfar Ataei ◽  
Karl Henning Halse ◽  
Hans Petter Hildre ◽  
Egil Tennfjord Mikalsen
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Simulation Software ◽  
Economic Feasibility ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
General Arrangement ◽  
Lifting System ◽  
And Control ◽  
Offshore Crane

Abstract Due to the ever higher demands from the energy market, the quantity, dimension and power capacity of newly installed offshore wind turbines are continuously increasing. In terms of logistical management, economic feasibility and engineering difficulty, the traditional installation methods, predominantly represented by using Jack-up vessel and offshore cranes, will hit their limitations soon in the future. Offshore turbines have a relatively fixed geometric profile and physical characteristics: a slender cylindrical tower with huge blades attached on the top end. In this work, we exploited these features and designed a low-height lifting system for deploying wind turbine onto a floating spar platform. The low-height lifting system lifts the wind turbine with wires attached to the bottom of the tower, and keeps the balance of the tower with extra tug lines on the mid-section. The wires and tug lines are controlled by an active 6DOF compensation system. The low-height lifting system removes the necessity of a huge offshore crane onboard and can scale well to even larger wind turbines. The design is virtual prototyped in the simulator of Offshore Simulator Centre using FATHOM simulation software. Different design configurations are discussed in terms of the general arrangement, system dimensions and control methods.

scholarly journals A Surface Ice Module for Wind Turbine Dynamic Response Simulation Using FAST

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Bingbin Yu ◽  
Dale G. Karr ◽  
Huimin Song ◽  
Senu Sirnivas
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Structural Response ◽  
Simulation Software ◽  
Offshore Wind ◽  
Foundation Soil ◽  
Offshore Wind Turbines ◽  
Ice Failure ◽  
Lock In

Developing offshore wind energy has become more and more serious worldwide in recent years. Many of the promising offshore wind farm locations are in cold regions that may have ice cover during wintertime. The challenge of possible ice loads on offshore wind turbines raises the demand of modeling capacity of dynamic wind turbine response under the joint action of ice, wind, wave, and current. The simulation software FAST is an open source computer-aided engineering (CAE) package maintained by the National Renewable Energy Laboratory. In this paper, a new module of FAST for assessing the dynamic response of offshore wind turbines subjected to ice forcing is presented. In the ice module, several models are presented which involve both prescribed forcing and coupled response. For conditions in which the ice forcing is essentially decoupled from the structural response, ice forces are established from existing models for brittle and ductile ice failure. For conditions in which the ice failure and the structural response are coupled, such as lock-in conditions, a rate-dependent ice model is described, which is developed in conjunction with a new modularization framework for FAST. In this paper, analytical ice mechanics models are presented that incorporate ice floe forcing, deformation, and failure. For lower speeds, forces slowly build until the ice strength is reached and ice fails resulting in a quasi-static condition. For intermediate speeds, the ice failure can be coupled with the structural response and resulting in coinciding periods of the ice failure and the structural response. A third regime occurs at high speeds of encounter in which brittle fracturing of the ice feature occurs in a random pattern, which results in a random vibration excitation of the structure. An example wind turbine response is simulated under ice loading of each of the presented models. This module adds to FAST the capabilities for analyzing the response of wind turbines subjected to forces resulting from ice impact on the turbine support structure. The conditions considered in this module are specifically addressed in the International Organization for Standardization (ISO) standard 19906:2010 for arctic offshore structures design consideration. Special consideration of lock-in vibrations is required due to the detrimental effects of such response with regard to fatigue and foundation/soil response. The use of FAST for transient, time domain simulation with the new ice module is well suited for such analyses.

Study on a global control strategy for rotation speed with different work states in variable-speed constant-frequency wind turbines

2011 ◽  
Vol 225 (7) ◽  
pp. 968-976 ◽  
Author(s):  
G Zheng ◽  
H Xu ◽  
X Wang ◽  
J Zou
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Control Strategy ◽  
Control Strategies ◽  
Stable Operation ◽  
Constant Frequency ◽  
Global Control ◽  
Control Rules ◽  
The Individual ◽  
And Control

This paper studies the operation of wind turbines in terms of three phases: start-up phase, power-generation phase, and shutdown phase. Relationships between the operational phase and control rules for the speed of rotation are derived for each of these phases. Taking into account the characteristics of the control strategies in the different operational phases, a global control strategy is designed to ensure the stable operation of the wind turbine in all phases. The results of simulations are presented that indicate that the proposed algorithm can control the individual phases when considered in isolation and also when they are considered in combination. Thus, a global control strategy for a wind turbine that is based on a single algorithm is presented which could have significant implications on the control and use of wind turbines.

scholarly journals On mooring line tension and fatigue prediction for offshore vertical axis wind turbines: A comparison of lumped mass and quasi-static approaches

2018 ◽  
Vol 42 (2) ◽  
pp. 97-107 ◽  
Author(s):  
D Cevasco ◽  
M Collu ◽  
CM Rizzo ◽  
M Hall
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Line Tension ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Mooring Line ◽  
Offshore Wind Turbine ◽  
Vertical Axis Wind Turbine ◽  
Lumped Mass ◽  
Vertical Axis Wind Turbines

Despite several potential advantages, relatively few studies and design support tools have been developed for floating vertical axis wind turbines. Due to the substantial aerodynamics differences, the analyses of vertical axis wind turbine on floating structures cannot be easily extended from what have been already done for horizontal axis wind turbines. Therefore, the main aim of the present work is to compare the dynamic response of the floating offshore wind turbine system adopting two different mooring dynamics approaches. Two versions of the in-house aero-hydro-mooring coupled model of dynamics for floating vertical axis wind turbine (FloVAWT) have been used, employing a mooring quasi-static model, which solves the equations using an energetic approach, and a modified version of floating vertical axis wind turbine, which instead couples with the lumped mass mooring line model MoorDyn. The results, in terms of mooring line tension, fatigue and response in frequency have been obtained and analysed, based on a 5 MW Darrieus type rotor supported by the OC4-DeepCwind semisubmersible.

Efficient Transient Analysis of the High-Speed Stage of a Wind Turbine Gearbox by Advanced Model Reduction Techniques and Memory-Effective Discretization

2015 ◽  
Author(s):  
Tommaso Tamarozzi ◽  
Bart Blockmans ◽  
Wim Desmet
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
High Speed ◽  
Dynamic Effects ◽  
Wind Turbine Gearbox ◽  
Premature Failure ◽  
Efficient Simulation ◽  
Model Complex ◽  
Non Linear ◽  
Flexible Multibody

Modern wind turbines are designed to cope with their increased size and capacity. One of the most expensive components of these machines is the gearbox. Its design is more complex than a mere upscaling exercise from predecessors. The stress levels experienced by the different gear stages, the dynamic effects induced by their size and the unparalleled loads transmitted are some of the challenges that design engineers face. Moreover, unexpected events that load the wind turbines such as voltage dips, wind gusts or emergency breaking are expected to be major contributors to the premature failure of these gearboxes. The lack of engineering experience at this scale calls for accurate and efficient simulation tools thereby enabling reliable gearbox design. Standard lumped-parameters models or rigid multibody approaches do not provide a sufficient level of details to study the dynamic effects induced by e.g. gear design modifications (micro-geometry) or to analyze local stress concentrations. More advanced numerical tools are available such as flexible multibody or non-linear FE and allow to model complex contact interactions including all the relevant dynamic effects. Unfortunately the level of mesh refinement needed for an accurate analysis causes these simulations to be computationally expensive with time scales of several weeks to perform a single full rotation of a gear pair. This work introduces a novel efficient simulation tool for dynamic analysis of transmissions. This tool adopts a flexible multibody paradigm but incorporates several advanced features that allows to run simulations up to two orders of magnitudes faster as compared to non-linear FE with the same level of accuracy. A unique non-linear parametric model order reduction technique is used to develop a simulation strategy that is quasi mesh-independent allowing the usage of very fine FE meshes. Finally, in order to limit the memory consumption, a technique is developed to be able to finely mesh only a few of the gears teeth while the remaining gears are coarsely meshed. The main novelty of this approach lies in the possibility to perform full gear rotations without losing spatial resolution as compared to a finely meshed gear. After an accuracy check performed with a sample pair of helical gears, the framework is used to simulate the high speed stage of a three-stage wind turbine gearbox. The combined efficiency and accuracy of the approach is demonstrated by performing a dynamic stress analysis of the high-speed stage with and without a tip-relief modification. Accuracy of the results, simulation time, and memory usage are assessed.

Decentralised Control Design for Load Mitigation in Horizontal Axis Wind Turbines (HAWTS)

2011 ◽  
Author(s):  
Fredrik Sandquist ◽  
Geir Moe ◽  
Olimpo Anaya-Lara
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Direct Method ◽  
Modeling And Control ◽  
Energy Capture ◽  
Pitch Control ◽  
Operating Region ◽  
Horizontal Axis Wind Turbines ◽  
Decentralised Control ◽  
And Control

In modern MW-size machines it has become a common practice to introduce controllers that provide active damping of turbine components to reduce blade, tower and drive-train loads, whilst optimising energy capture. However, as wind turbines become larger and more flexible, these controllers have to be designed with great care as the coupling between flexible modes increases and so does the potential to destabilise the turbine. The most direct method to address the above issues has been to exploit the pitch control capabilities. Individual Pitch Control (IPC) has been proposed many times over the last few years for load mitigation. Bearing this in mind, this paper investigates two different approaches to design a controller to pitch each blade individually in the wind turbine operating region III. The first one is a decentralised control algorithm and the second one is an H∞ loop shaping design. A controllability analysis of the wind turbine is also included in the paper. The investigation is conducted based on the NREL 5MW benchmark wind turbine. Turbine modeling and control is conducted in FAST and Simulink.

Dynamics Simulation for Horizontal-Axis Wind Turbines

2011 ◽  
Vol 382 ◽  
pp. 129-132
Author(s):  
Xu Ning Mao ◽  
Ji Shun Li ◽  
Yi Liu
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Simulation Software ◽  
Horizontal Axis ◽  
Dynamics Simulation ◽  
Operating Characteristics ◽  
Horizontal Axis Wind Turbines ◽  
Dynamic Operating ◽  
Mechanical Dynamics ◽  
Turbine Design

In this study, the dynamic characteristics of three-blade horizontal¬-axis wind turbines were simulated, based on the aerodynamic software AeroDyn, wind turbine design software FAST and mechanical dynamics simulation software ADAMS. AeroDyn and FAST are Interface codes for ADAMS. As the pre-processor of ADAMS, FAST code helps to build wind turbine model as well as constrains ,while AeroDyn code applies wind field data to the model. At last the model was imported into ADAMS to be simulated. In this way, the dynamic operating characteristics of three-blade horizontal¬-axis wind turbines can be obtained. And the load-time curves of the blade roots can also be gotten. Results show that the method adopted is feasible and reliable.

scholarly journals Control Algorithm for Parallel Connected Offshore Wind Turbine Generators

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4670
Author(s):  
Emir Omerdic ◽  
Jakub Osmic ◽  
Cathal O’Donnell ◽  
Edin Omerdic
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Wind Turbines ◽  
Control Algorithm ◽  
Low Frequency ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Power Extraction ◽  
Turbine Generators ◽  
Wind Turbine Generators

A control algorithm for Parallel Connected Offshore Wind Turbines with permanent magnet synchronous Generators (PCOWTG) is presented in this paper. The algorithm estimates the optimal collective speed of turbines based on the estimated mechanical power of wind turbines without direct measurement of wind speed. In the proposed topology of the wind farm, direct-drive Wind Turbine Generators (WTG) is connected to variable low-frequency AC Collection Grids (ACCG) without the use of individual power converters. The ACCG is connected to a variable low-frequency offshore AC transmission grid using a step-up transformer. In order to achieve optimum wind power extraction, the collective speed of the WTGs is controlled by a single onshore Back to Back converter (B2B). The voltage control system of the B2B converter adjusts voltage by keeping a constant Volt/Hz ratio, ensuring constant magnetic flux of electromagnetic devices regardless of changing system frequency. With the use of PI pitch compensators, wind power extraction for each wind turbine is limited within rated WTG power limits. Lack of load damping in offshore wind parks can result in oscillatory instability of PCOWTG. In this paper, damping torque is increased using P pitch controllers at each WTG that work in parallel with PI pitch compensators.

CFD and Control Analysis of a Smart Hybrid Vertical Axis Wind Turbine

2018 ◽  
Author(s):  
Arian Hosseini ◽  
Navid Goudarzi
Keyword(s):  
Wind Turbine ◽  
Vertical Axis ◽  
Power Coefficient ◽  
Control Analysis ◽  
Vertical Axis Wind Turbine ◽  
Aerodynamic Properties ◽  
Switch Mechanism ◽  
Electro Magnetic ◽  
Operational Range ◽  
And Control

Wind energy has become a dominant source of renewable energy during the past decade. Current hybrid wind turbines are primarily designed and manufactured based on a combination of aerodynamic properties for both Darrieus and Savonius turbines. In this work, the aerodynamic performance characteristics of a smart vertical axis wind turbine (VAWT) with an electro-magnetic switch mechanism for dis-/engagement mechanism is studied analytically and numerically. The proposed novel VAWT offers a high start-up torque by a Savonius turbine and high power coefficient values by a Darrieus turbine. The switch mechanism can further improve the system efficiency by running the turbines together or independently. The proposed hybrid VAWT was modeled as a combined Savonius-type Bach turbine and a 3-bladed H-Darrieus turbine. The hybrid turbine has a self-startup feature and reaches a coefficient of power (Cp) of over 40%. The turbine is also estimated to cover a wide operational range up to TSR 6. The follow on research phases of the project include studying the proposed smart VAWT experimentally and validating the results with those obtained through computational analysis.

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