电网扰动下双馈风电机组传动链扭振疲劳寿命损耗研究

Due to the fast electrical control with the grid disturbance, the flexible drive train of wind turbine generator system (WTGS) will result in the long time torsional vibration, and the traditional method could not be used the on-line monitoring and quantify assessment on the torsional fatigue life expenditure of the drive train. Regarding to the drive train torsional fatigue resulted from the electromagnetic torque dynamical fluctuation of the doubly fed induction generator (DFIG), the dynamics modeling, shaft key parameters identification and torsional fatigue life expenditure assessment of the WTGS drive-train are investigated in this proposal. Firstly, the proposal will establish the multi-body drive-train dynamics models by including the key components flexibility, and will obtain the effects on the drive-train torsional vibration from the DFIG electrical control. Then, by introducing the equivalent parameters from the effects of the electrical control and by considering the time-varying characteristics of the drive-train shaft parameters, the proposal will investigate the methods on the extraction and on-line identification for the drive-train equivalent key parameters, and get the dynamic responses of the drive-train key components torsional vibration for the WTGS under the different grid disturbances. Finally, based on the nonlinear fatigue damage cumulative theory, the proposal will establish the models of the torsional fatigue expenditure and the lifetime prediction, which can reflect the cumulative effects on the different life cycles and the different electromagnetic torques. Furthermore, the proposal will present the on-line assessment and the active control strategies of the drive train torsional fatigue life expenditure by using the proposed characteristics on the electromagnetic torque with the torsional stress. The proposal achievements will have the important practical and academic significance to improve the WTGS operational safety and the connected-grid stability, which also could provide the scientific basis to the improved health monitoring and the life management for the WTGS.

由于电网扰动下的快速电气控制，风电机组柔性结构的传动链轴系极易造成持续扭振，现有方法难以在线监测和准确评估其扭振疲劳寿命的损耗。项目围绕双馈发电机电磁转矩动态变化引起的传动链扭振疲劳问题，开展风电机组传动链动力学建模、传动链关键参数辨识、扭振疲劳寿命损耗评估及控制研究。项目建立计及关键部件柔性的多自由度传动链模型，探索双馈发电机控制对传动链扭振影响规律；引入电气控制影响等效参数，考虑轴系参数时变性，研究传动链等效关键参数的提取和在线辨识方法，获取电网扰动下风电机组传动链关键部件扭振的动态响应；应用非线性疲劳累积损耗理论，建立能反映不同寿命周期和不同电磁转矩累积作用的扭振疲劳损耗计算及寿命预测模型，提出基于电磁转矩-扭应力疲劳特性的传动链扭振疲劳寿命损耗在线评估及主动控制策略。研究成果对提高风电机组运行安全及系统稳定性具有重要意义和学术价值，为完善风电机组健康状态评估和寿命管理提供科学依据。

双馈风电机组柔性传动链在电网扰动及其快速电气控制作用下极易造成持续扭振，其寿命疲劳损耗的检测与评估日益受到业内重视。项目围绕双馈风电机组电磁转矩动态变化引起的传动链扭振疲劳问题，主要开展了传动链动力学建模、关键参数辨识、扭振疲劳寿命损耗评估及机组稳定性分析与主动控制4个方面的研究。①建立了考虑齿轮箱、轴承等关键部件柔性的传动链三维实体有限元模型与双馈机组电气系统模型相联合的机电耦合模型，开展了宽频率范围内各关键部件模态分析，获取了关键部件扭振频率分布，揭示了主轴应力分布和扭振特性。②针对传动链等效参数时变难以辨识的问题，提出了基于改进粒子群算法的双馈风电机组传统链机-电参数辨识方法。③针对传动链轴承实时剩余寿命难以预测问题，建立了轴承性能退化模型，提出了基于逆高斯分布的实时剩余寿命预测方法，实现了实时剩余寿命预测。针对风电传动链电气部件-变流器的可靠性与疲劳寿命损耗，提出了计及电网扰动与故障穿越累积效应的多时间尺度寿命评估模型，获取了其寿命分布规律。基于以上评估方法，最终建立了考虑实时扭振状态信息，基于电磁转矩高、低频特性的风电机组传动链寿命评估模型，研究了电网故障扰动下传动链短期疲劳损伤和长期累积疲劳寿命，发现了电磁转矩的高、低频特性与传动链扭振的耦合关系和传递规律，预测了传动链的不同周期下的寿命。④针对机网交互作用下风电机组稳定性问题，设计了电网常见振荡的快速检测与主动保护方法，建立了传统矢量和虚拟同步两种控制策略下的双馈机组阻抗模型，发现了虚拟同步控制下双馈机组具有更强的机网友好性，并提出了锁相环参数自适应的电网友好型主动控制策略。在此基础上，引入等效阻尼、刚度，以及序电流等，提出了基于电气阻尼-刚度协调控制的扭振主动抑制策略，并进行了寿命评估验证。项目成果对提高风电机组传动链运行可靠性、优化风电机组控制策略、提升风电机组健康状态评估及寿命管理水平具有重要的学术价值和现实意义。