Effects of gear modifications on the dynamic characteristics of wind turbine gearbox considering elastic support of the gearbox

Shuaishuai Wang,Caichao Zhu,Chaosheng Song,Huachao Liu,Jianjun Tan,Houyi Bai 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.3

The reliability and service life of wind turbines are directly influenced by the dynamic performance of the gearbox under the timevarying wind loads. The control of vibration behavior is essential for the achievement of a 20-year service life. We developed a rigidflexible coupled dynamic model for a wind turbine gearbox. The planet carrier, the housing, and the bedplate are modelled as flexibilities while other components are assumed as rigid bodies. The actual three points elastic supporting are considered and a strip based mesh model is used to represent the engagement of the gear pairs. The effects of gear tooth modifications on the dynamics were investigated. Finally, we conducted a dynamic test for the wind turbine gearbox in the wind field. Results showed that the contact characteristics of gear pairs were improved significantly; the peak-to-peak value of transmission error of each gear pair was reduced; the amplitudes of the vibration acceleration and the structural noise of the wind turbine gearbox were lowered after suitable tooth modification.

풍력발전기용 피치 기어박스 가속수명시험에 관한 연구

이용범(Young-Bum Lee),이기천(Gi-Chun Lee),최병오(Byoung-Oh, Choi) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

Wind turbine, which is attracting part of the renewable energy and is researching continuously, is going to be large size for high efficiency. There is a pitch system to control the blade position to match with angle of the blade to make good efficiency in the wind turbine system. The wind turbine is focusing on the reliability improvement because working environment effect is bigger than any other points and specially, the reliability improvement of the pitch gear box is required by the customer because it is the key component of the wind turbine. Because of this, the establishment of criteria for pitch gearbox is required to make the methods of assessment because pitch gearbox is the part of the wind turbine closely related with ensuring the reliability. So, this study did the failure analysis of the pitch gearbox system, which is consisted with 6 or 9 sets of pitch gearboxes through researching and analyzing the site conditions. Also this study designed the life test method based on the failure analysis and working condition of the pitch gearbox. To design the accelerated life test of the pitch gearbox, this study have been considered the torque, lubrication condition, and frequency of use and etc. Finally, this selected the torque as the acceleration factor which is affected mainly to the system and also, the test equipment was developed based on the requirements of the life and performance test.

Evaluating the influence of a high-fidelity generator model on the gearbox dynamic responses of wind turbines

Yunpeng Zhou,Chengwu Lee 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.12

This study evaluates the influence of a high-fidelity generator model on the dynamic responses of the gears and bearings of a 1 MW wind turbine. Fully coupled aeroelasticservo-control numerical models with simplified and high-fidelity generators of the wind turbine are established. The numerical models are then verified through comparisons with another software in terms of natural characteristics and dynamic responses in the time domain. Dynamic analyses of the numerical models of the wind turbine are conducted under several environmental conditions. The external dynamic load excitation and internal load effects of the gearbox of the wind turbine numerical models with the simplified and high-fidelity generators are compared. The long-term fatigue damage of the gears and bearings of the two numerical models is also calculated and compared. Results show that the high-fidelity generator model increases the gearbox’s external and internal load fluctuations due to power grid and generator control effects. The high-fidelity generator model results in higher fatigue damage of the gears and bearings in the gearbox in comparison with the fatigue damage in the simplified generator model. This study provides a crucial basis for the design and dynamic analysis of wind turbine gearboxes.

10MW급 해상풍력발전기 드라이브 트레인을 위한 마그네틱 기어의 속도별 설계 및 출력밀도 특성분석

김찬호(Chan-Ho Kim),김용재(Yong-Jae Kim) 대한전기학회 2015 전기학회논문지 Vol.64 No.12

The diameter of the rotor of 2MW wind turbine is being developed by a number of companies with more than 80m, reliability and economic efficiency of the wind power generator has been improved. The need for large-scale wind turbine with excellent economy has been attracting attention because the new orders and the location of the wind turbine market has reached a limit. Technology development for enlargement of wind turbine is possible not only the improvement of energy efficiency but also reduce the construction costs per unit capacity. However, mechanical gearboxes used in wind generators have problems of wear, damage, need for lubrication oil and maintenance. Therefore, we want to configure the gearbox of a large-scale wind turbine using a magnetic gear in order to solve these problems of mechanical gearbox.

A Novel Vibration Model for Explanation of the Frequency Features in Multistage Wind Turbine Gearboxes Considering the Effects of Inter-stage Meshing Frequency Modulation

Yanyan Nie,Fangyi Li,Liming Wang,Jianfeng Li,Yanle Li,Mingshuai Sun,Mengyao Wang,Guoyan Li 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.1

As a kind of green energy, wind energy has become cost-competitive mainstream energy in the world. The gearbox is one of the most important and vulnerable components in the wind turbine (WT), which suffers a high failure rate and downtime. It is of great significance to the condition monitoring and fault diagnosis of the WT gearbox. However, in the multistage WT gearbox, the vibrations generated from different stages are coupled, which leads to a complex vibration spectral structure and brings difficulties in condition monitoring and fault diagnosis. Aiming to understand the vibration frequency features of multistage WT gearboxes, a novel phenomenological vibration model is established and the spectral structure is deduced by using the Fourier series analysis. In the vibration model, the phenomenon of inter-stage meshing frequency modulation (ISMFM) is considered, which is clearly proposed for the first time. The theoretical derivations are validated by both simulation and engineering tests using a 2.0 MW industrial WT gearbox. The results show that under healthy conditions, in addition to the meshing frequencies and their harmonics of each stage, there are also ISMFM sidebands in the vibration spectrum of the multistage WT gearbox, and the amplitude of the sidebands will change with the health status of the gearbox. The findings are not only applicable to the WT gearbox studied in this paper, but also to other similar multistage gearbox systems, which can provide a priori spectral structure for a multistage gear transmission system to assist its condition monitoring and fault diagnosis.

풍력 발전기용 증속기의 유연 핀이 수명에 미치는 영향 연구

박영준(Young-Jun Park),이근호(Geun-Ho Lee),남용윤(Yong-Yun Nam),김정길(Jeong-Kil Kim) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.9

풍력발전기용 증속기의 유성기어열에서 한단 지지 캐리어에 유연 핀을 적용하여 유성 축과 유연핀의 변형에 의한 자기 정렬 효과가 증속기 유성기어열의 수명에 미치는 영향에 대한 연구를 수행하였다. 유성기어열의 하중 분배 효과를 분석하기 위하여 오일러 이론과 상용 프로그램을 이용하였다. 풍력발전기용 증속기에 한단 지지 캐리어와 유연 핀이 사용됨에 따라 유성기어의 미스얼라인먼트, 치면 하중분포 계수 및 요구수명이 만족할 만한 성능 향상을 가져왔으며, 특히 요구수명에 있어서 증속기가 요구하는 20 년 보증 수명을 만족하는 것으로 확인되었다. An overhung mounted carrier with flexible pins is applied to the planetary gear train of a wind turbine gearbox to investigate the influence of the self-aligning effect by means of the deflection of the planet spindle and the flexible pin on the lifetime of the planet gear for a wind turbine gearbox. To analyze the load distribution of planet gears, both Euler theory and commercial software are employed. By applying an overhung mounted carrier with flexible pins in the wind turbine gearbox, we can improve the misalignment performance, face load factor, and service life of the planet gears. In particular, it was confirmed that a service life of more than 20 years could be realized for wind turbine gearboxes by applying a flexible pin to the overhung mounted carrier.

Finite element structural analysis of wind turbine gearbox considering tooth contact of internal gear system

조진래,임오강,박노길,Min-Ho Park,Dae-Suk Shin,정기용 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.7

Gearbox for wind turbine must be designed to have the sufficient structural strength to sustain the extreme torque and forces transferred from rotor blades. Traditionally, the structural analysis of gearbox has been made using the simplified FEM models in which the contacts between gear teeth are replaced with the equivalent forces acting on the gear shafts, because the consideration of the detailed internal gear transmission system requires a huge number of degrees of freedom. But, the traditional method can neither accurately reflect the gear transmission forces, nor is it preferable for the dynamic analysis. In order to solve these problems, a structural analysis method considering the tooth contact of internal gear system is introduced in this paper. The actual tooth contact between a pair of gears is modeled with spring elements and the spring constants are determined through the stiffness analysis of gear teeth. The current analysis technique is justified through the comparison with the simplified gear system model and applied to the structural analysis of a 2-stage differential-type gearbox for wind turbine.

풍력발전기용 Yaw gearbox의 가속 수명시험에 관한 연구

이용범,이기천,이종직,임신열 사단법인 유공압건설기계학회 2024 드라이브·컨트롤 Vol.21 No.1

The yaw gearbox is a key device in a wind power generator that improves power generation efficiency by rotating hundreds of tons (400 to 600 tons) of nacelle so that the blade reaches 90 degrees in the wind direction. Recently, installation sites have been advancing from land to sea as they have become super-large at (8-12) MW to increase the economic feasibility of wind power generators and utilize excellent wind resources, and the target life of large wind power generators is 25 to 30 years. The yaw gearbox of 6 to 12 sets is installed in a very complex place inside the nacelle on the tower with parallels, and it is important to secure the reliability of the yaw gearbox because if a failure occurs after installation, it costs tens to hundreds of times the price of a newproduct to restore. In this study, equivalent loads were calculated by analyzing failure mode and field data, accelerated life test conditions were established, and a test device was constructed to perform the accelerated life tests and performance tests to ensure the reliability of the gearbox.

A Study of a Novel Wind Turbine Concept with Power Split Gearbox

Liu, Qian,Appunn, Rudiger,Hameyer, Kay Journal of International Conference on Electrical 2013 Journal of international Conference on Electrical Vol.2 No.4

This paper focuses on the design and control of a new concept for wind turbines with a planetary gearbox to realize a power split. This concept, where the generated wind power is split into two parts, is to increase the utilization of the wind power and may be particularly suitable for large scale off-shore wind turbines. In order to reduce the cost of the power electronic devices, a synchronous generator, which is driven by the planetary gear, is directly connected to the power grid without electronic converter. A servo drive, which functions as the control actuator, is connected to the power grid by a power electronic converter. With small scale power electronic device, the current harmonics can also be reduced. The speed of the main shaft is controlled to track the optimal tip speed ratio. Meanwhile the speed of the synchronous generator is controlled to stay at the synchronous speed. The minimum rated power of the servo motor and the converter, is studied and discussed in this paper. Different variants of the wind turbine with a planetary gear are also compared. The controller for optimal tip speed ratio and synchronous speed tracking is given.

누적손상이론을 이용한 풍력증속기의 가속수명시험법 개발

손기수(Son, Ki-Su),곽희성(Kwak, Hee-Sung),강창훈(Kang, Change-Hoon),조준행(Cho, Jun-Haeng) 한국신재생에너지학회 2005 한국신재생에너지학회 학술대회논문집 Vol.2005 No.11

This study was performed to develop accelerated life test method of the wind-turbine gearbox using accumulated damage theory that used to model the fatigue of parts that receive variable load. The accumulated damage theory was introduced, and the estimation of life and calculation of accelerated life test time was illustrated. As the actual application example, accelerated life test method of the gearbox was described. Life distribution of the wind-turbine gearbox was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 140,600 hours and 99% reliability for one test sample According to the accumulated damage theory, because test time can shorten in case increase test load, test time could be reduced by 1.2 years when we put the load 1.2 times of rated load than 0.93 times of rated load that is equivalent load calculated by load spectrum of the wind turbine. This time, acceleration coefficient was 21.3. This accelerated test method was used to develop accelerated test method of gear reducer, gear and bearing as well as the industrial gearbox and it is considered to be applied comprehensively to mechanical parts the fatigue of which is happened by load or pressure etc.