Electromagnetomechanical Coupled Vibration Analysis of a Direct-Drive Off-Shore Wind Turbine Generator

In large direct-drive off-shore wind turbine generators one challenge is to engineer the system to function securely with an air gap length of about a thousandth of the outer rotor diameter. Compared to the large diameter of the generator rotor, the rolling element bearings can only be constructed with a relatively limited size. This makes it challenging to design appropriate constructions able to transmit the large applied magnetic forces encountered in the air gap of direct drive wind turbine generators. Currently, this challenge is met by designing stiff heavy rotors that are able to withstand the forces in the air gap. Incorporating flexibility into the design of the rotor structure can lead to a lighter less expensive rotor. In order to be able to do this the magnetomechanical coupling in the air gap and its effect on the structural dynamics need to be taken into account when predicting the intended flexibility. This paper introduces an approach for a multiphysical modal analysis that makes it possible to predict the dynamics of the strongly coupled magnetomechanical system. The new method is validated using measurements of a simple lab setup. It is then applied to a single-bearing design direct-drive wind turbine generator rotor to calculate the changes of the structural dynamics caused by the electromagnetomechanical coupling.

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Computer Simulation and Design of the Control System for a Wind Turbine Generator

Journal of Mechanical Design ◽

10.1115/1.3254706 ◽

1980 ◽

Vol 102 (1) ◽

pp. 14-18

Author(s):

H. Sambar ◽

V. Pavelic ◽

R. J. Warner

Keyword(s):

Control System ◽

Wind Turbine ◽

Hydraulic System ◽

Load Condition ◽

Turbine Generator ◽

Wind Turbine Generator ◽

Turbine Generators ◽

Wind Turbine Generators ◽

Control Concept ◽

New Generation

This project is a part of an overall study aimed at producing a new generation of wind turbine generators. The wind turbine generator proposed is a horizontal axis machine with three blades operating downwind. A hydraulic system actuates mechanical linkages to control blade pitch during operation. The blade pitch control concept provides active control of rotor rpm above the rated wind speed and during no load condition. The lowering of blade and tower loads while providing the capability for well tuned rotor control are its primary features. A hydraulic system, designed to control the pitch of the blades of a wind turbine generator, is simulated on the digital computer using the Runge-Kutta method. The control system subroutine is coupled with the aerodynamic subroutines of the blades to represent the model for the wind turbine generator. The response of the simulated wind turbine to a real wind case is shown to agree with the desired response.

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Fault diagnosis of wind turbine generator bearings using fast spectral correlation

Wind Engineering ◽

10.1177/0309524x211046381 ◽

2021 ◽

pp. 0309524X2110463

Author(s):

Jin Xu ◽

Xian Ding ◽

Jiuhua Wang ◽

Junjie Zheng

Keyword(s):

Wind Turbine ◽

High Speed ◽

Computational Cost ◽

Turbine Generator ◽

Spectral Correlation ◽

Wind Turbine Gearbox ◽

Wind Turbine Generator ◽

Turbine Generators ◽

Wind Turbine Generators ◽

Diagnosis Accuracy

Bearings are the critical parts that support the rotating of rotor of wind turbine generators. Due to high speed revolution and affected by potential misalignment between rotor and the high speed shaft in wind turbine gearbox, the fault ratio in wind turbine generator bearings is high. Once the bearings fail, it will cause gap eccentricity, even rub, or sweeping chamber between rotor and stator. Under fault conditions, the vibration signals from rotating machinery exhibits distinct second cyclostationarity. In the light of this, the fast spectral correlation based method is applied to the fault extraction of bearings in wind turbine generators. Through converting conventional correlation into summation algorithm, the computational cost is reduced largely, meanwhile, the diagnosis accuracy is guaranteed. The effectiveness of the method in this paper is verified by two fault cases from on-site wind turbines.

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Augmenting the signal processing–based mitigation techniques for removing wind turbine and radar interference

Wind Engineering ◽

10.1177/0309524x20948543 ◽

2020 ◽

pp. 0309524X2094854

Author(s):

Ashish Sharma ◽

V Chintala

Keyword(s):

Signal Processing ◽

Wind Turbine ◽

Traffic Control ◽

Radar Signal ◽

Turbine Generator ◽

Wind Turbine Generator ◽

Turbine Generators ◽

Wind Turbine Generators ◽

Doppler Techniques ◽

Mitigation Techniques

The interference between wind turbine generators and radar is now being considered as one of the major deterrents towards seeking clearance for new wind energy project. The windfarm developers have to seek clearance from Civil Air Traffic Control and Defence Department certifying that the windfarms will not create interference with radars. The tower of wind turbine generator along with blades presents a large radar cross section to radars, thus creating static clutter; moreover, rotation of wind turbine generator blades creates Doppler ambiguities which confuse radar operators. Many radar designers have proposed mitigation techniques to overcome this issue; however, each technique has its own limitation. The study takes a two-pronged approach to address the issue of wind turbine generator static clutter due to tower and blades and the resolution of Doppler ambiguities through signal processing–based mitigation techniques. In addition, the study also suggests the use of micro-Doppler techniques for signature identification of wind turbine generator blades for eliminating their effect during the radar signal processing. The article presents a step-by-step mitigation technique to resolve the wind turbine generator and radar interference issue.

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Dynamic Response of a Lightweight Stator Structure for a Large Diameter Direct-Drive Wind Turbine Generator

Mechanisms and Machine Science - Proceedings of the 10th International Conference on Rotor Dynamics – IFToMM ◽

10.1007/978-3-319-99272-3_35 ◽

2018 ◽

pp. 503-517

Author(s):

Charles Nutakor ◽

Scott Semken ◽

Janne Heikkinen ◽

Jussi Sopanen ◽

Aki Mikkola

Keyword(s):

Dynamic Response ◽

Wind Turbine ◽

Large Diameter ◽

Direct Drive ◽

Turbine Generator ◽

Wind Turbine Generator

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Research on the Faults due to Bearing-Gear Mismatching in Gearbox of Wind Turbine Generator

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.889-890.537 ◽

2014 ◽

Vol 889-890 ◽

pp. 537-541

Author(s):

Cheng Zhi Zeng ◽

De Yao Tang ◽

Yi Gao

Keyword(s):

Wind Turbine ◽

Design Method ◽

Planetary Gear ◽

Turbine Generator ◽

Wind Turbine Generator ◽

Turbine Generators ◽

Wind Turbine Generators ◽

Matching Design ◽

Planetary Gear System ◽

Doubly Fed

In order to lower down the fault rate of bearings and gears, tighten up the mechanical components safety and lengthen their lifetime, a new design method [ has occurred by matching bearings with gears. Whereas, this methodology is based on the simple transmission system, and it seems not applicable in more complicated transmission systems, such as gearboxes in doubly-fed wind turbine generators, which really need to be further studied, and thats where the topic of this article lies. By doing research on the bearing-gear matching design of planetary gear system in gearbox of wind turbine generator, equations are worked out. Succeedingly, by verifying the data from simulating experiments and on-site cases, it turns out that the spectrum characteristics of those two kinds of data match with each other correctly, and as a consequence, the new matching design is thus proved to be available.

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Vibration and noise studies on wind turbine generator for reduction of vibrations and noise

World Journal of Engineering ◽

10.1108/wje-09-2019-0275 ◽

2020 ◽

Vol 17 (1) ◽

pp. 134-143

Author(s):

Ramakrishna Shinagam ◽

Guntaka Ajay ◽

Lokanadham Patta ◽

Anand Siva Gandam

Keyword(s):

Wind Turbine ◽

Natural Frequency ◽

Vibration Velocity ◽

Rotational Axis ◽

Turbine Generator ◽

Content Type ◽

Steel Coil ◽

Wind Turbine Generator ◽

Turbine Generators ◽

Wind Turbine Generators

Purpose Wind power is the one of best natural resources to meet the demands of electricity in India. In this regard, one of engineering college in Visakhapatnam has procured wind turbine generators of 200 kWp and got these installed on the rooftop of the college buildings for research and power generation. After starting the mills, huge vibrations were experienced by the staff and students in the laboratories and classrooms. So, the purpose of this paper is to carry out vibration and noise studies on wind turbine generator to identify the problem for high vibrations and suggest a novel method for vibration reduction. Design/methodology/approach Experimental vibration and natural frequency investigations are carried when wind velocity around 6.0 m/s using frequency analyzer, impact hammer, condenser microphone and accelerometer. An attempt is made to reduce the vibration and noise level of wind turbine generator by inserting a steel coil spring of 300 mm length having 20 turns in series with turnbuckle D shackle assembly, which is used to connect the wind turbine generator to the hook mounted on slab. Findings A high vibration velocity of 9.9 mm/s was observed on at base frame of wind turbine generator. The natural frequencies of hook and slab are observed in between 15 to 20 Hz from the natural frequency test. A high noise of 94.67 dBA is observed at a distance of 1 m from the base of wind turbine generator along the rotational axis of rotor. After modification to the baseline, WTG the vibration and noise levels are reduced to 4.8 mm/sec and 77.76 dBA, respectively. Originality/value This is the first time to study the huge vibrations generated in wind turbine generators installed on the rooftop of the college. Developed a novel methodology to reduce the vibrations by inserting a steel coil springs in turnbuckle D shackle assembly of wind turbine generators. After modification, wind turbine generator are running successfully without any high vibrations.

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Fabrication of a Scaled MgB2 Racetrack Demonstrator Pole for a 10-MW Direct-Drive Wind Turbine Generator

IEEE Transactions on Applied Superconductivity ◽

10.1109/tasc.2018.2815027 ◽

2018 ◽

Vol 28 (4) ◽

pp. 1-5 ◽

Cited By ~ 6

Author(s):

Niklas Magnusson ◽

Jan Christian Eliassen ◽

Asger Bech Abrahamsen ◽

Svein Magne Helleso ◽

Magne Runde ◽

...

Keyword(s):

Wind Turbine ◽

Direct Drive ◽

Turbine Generator ◽

Wind Turbine Generator

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Coupled Electromagnetic and Lattice Structure Optimization for the Rotor and Stator of Large Electric Machines

10.1115/power2021-62625 ◽

2021 ◽

Author(s):

Austin C. Hayes ◽

Gregory L. Whiting

Keyword(s):

Wind Turbine ◽

Lattice Structure ◽

Electric Machines ◽

Force Density ◽

Direct Drive ◽

Element Analysis ◽

Electromagnetic Design ◽

Turbine Generators ◽

Wind Turbine Generators ◽

Structural Mass

Abstract Permanent magnet direct drive (PMDD) electric machines are advantageous due to higher efficiencies and lower maintenance concerns. For wind turbine generators, especially offshore turbines, this is advantageous to geared machines and is currently implemented by manufacturers such as GE, Siemens and Enercon. By nature, a direct drive machine must be larger than its geared counterpart in order to output the same power. As a result, the structural mass is larger and makes the machine prohibitively large. However, the structural mass and electromagnetic design is coupled and the electromagnetic criteria are an important consideration in the structural design. In this analysis, the electromagnetic design of a 5 MW PMDD generator was coupled to a triply periodic minimal surface (TPMS) lattice generator through means of an evolutionary algorithm. Finite element analysis (FEA) was used to determine the radial, torsional, and axial deformations under simulated wind turbine generator loading conditions subject to critical deflection criteria. Lattice functional grading was completed with the FEA deflection data in order to further optimize the structural mass. For the 5 MW test case, functional graded TPMS support structures maintained stiffness for a generator with a 32% higher force density with inactive mass 4% lower than baseline. This study suggests functional grading of TPMS lattice structures for wind turbine generators has the potential at significant mass savings.

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