风力发电机组传动链动力学建模与仿真分析

依据德国劳氏船级社2010年发布的"风力发电机组传动系统动力学认证分析标准"(即GL 2010标准),以多体动力学仿真软件SIMPACK为仿真平台建立某型风力发电机组传动链多柔体动力学仿真模型,通过频域分析得到传动链的固有频率及能量分布图,并绘制二维坎贝尔图确定潜在共振点,通过时域仿真分析对潜在共振点进行验证,最终确定危险共振点,该文为风力发电机组传动链动力学建模与仿真提供了一种新方法,为传动链的稳定性和可靠性设计及动力学优化设计提供了理论参考。     

风力发电机组传动链振动特性研究及试验

建立风力发电机组主传动链振动特性全实物仿真分析模型。模型包括叶片、轮毂、主轴、齿轮箱、连轴器和发电机等,其中叶片、轮毂、主轴、齿轮箱内的行星架、各级旋转轴等以超单元模型的型式导入总模型。根据风力机设计参数计算得到风力机的激励频率,分别在切入、额定和切出的3种动平衡状态基础上计算风力机运行时的特征频率,并结合激励频率和特征频率绘制坎贝尔图及能量分布图,找出风力机的潜在共振点,最后对风力机进行时域扫频分析,结合三维坎贝尔图、傅里叶变换对潜在共振点进行排除或确认。分析结果表明:该款自主设计的风力发电机组具有良好的振动特性,可避免共振,并得到试验结果的验证。     

风电机组传动链柔性建模及电网故障响应特性研究

针对风电机组动态特性研究中传动链模型过于简化及对电网故障动态响应特性不足或缺失的问题。综合考虑风电机组传动链各部分的惯量、旋转阻尼、刚度特性等,采用弹簧阻尼质量建模方法,建立风电机组柔性传动链模型,分析说明柔性传动链的二阶欠阻尼系统本质及在电网故障过程中可能存在的扭矩振荡问题。首次考虑传动链柔性特性进行风电机组电网故障动态响应特性系统仿真研究,仿真结果验证理论分析的正确性。并在1.5 MW大容量风电机组上进行现场试验研究,试验结果有力支持了理论分析和仿真结果。     

计及齿轮全柔性的风电机组传动链有限元建模及扭振特性分析

大功率风电机组传动链关键部件柔性直接影响机组扭振特性及疲劳寿命,提出考虑齿轮柔性与啮合柔性的传动链有限元建模及扭振特性分析。首先,基于实际双馈风电机组传动链结构、材料属性与几何参数,考虑齿轮箱内齿轮柔性与齿轮啮合柔性,结合叶片、轮毂、主轴和发电机转子,建立风电机组传动链多柔体有限元模型。其次,基于有限元模态分析理论,提出一种基于矢量位移云图筛选扭振频率的分析方法,获取计及齿轮全柔性影响的风电机组中、低频范围的扭振模态,并与不同传动链模型结果进行比较,验证该文所建模型的有效性。最后,分别分析不同齿轮柔性和齿轮啮合柔性对传动链扭振频率和模态的影响。结果表明,该文所建模型不仅能反映传动链扭振固有的低频频率,而且能反映弯扭耦合产生的中频扭振频率,且相比齿轮啮合柔性,齿轮柔性系数影响传动链高频扭振特性明显。     

传动链模型对风机低电压穿越能力的影响

电网电压跌落故障时风电机组应能保持与电网连接并向系统不间断供电,根据风电机组在暂态过程中的表现提出低电压穿越(LVRT)要求。考虑传动轴扭转柔性因素,应用等效质量法,建立了变速恒频风电系统传动链的一质量块等效模型和二质量块等效模型。当发生电网电压跌落故障时,对采用不同传动链模型的风电系统进行仿真比较及理论分析。     

考虑风电机组传动链疲劳载荷的常态化惯量响应方法

风电机组参与系统惯量响应能够提高频率稳定性，但其传动链的疲劳载荷会显著增加不利于长时间稳定运行。为使风电机组能够进行常态化惯量响应，提出考虑传动链疲劳载荷的惯量控制方法，首先根据风电机组动力学特征建立其状态空间方程，再推导调频控制量与传动链扭矩波动的关系，通过疲劳载荷最小化和惯量响应出力范围约束实时求解风电机组功率参考值，通过每个积分步长上的功率调节同时实现疲劳载荷最小化和惯量响应能力的最大化，最后通过仿真对提出的方法进行验证。     

随机风载荷对双馈风电机组轴系扭振响应分析

考虑到风电机组柔性传动链在风速持续扰动中易产生机组扭振,研究随机风载荷作用下双馈风电机组扭振响应、扭振传递规律及关键部件的影响程度。首先,考虑叶片、齿轮箱和发电机等关键部件,采用集中质量法,建立双馈风电机组传动链等效3质量块模型。其次,基于小信号分析法对柔性传动链的扭振模态、扭振频率及参与因子进行分析,获取其模态振型图。最后,基于Simulink软件平台,建立考虑随机风载荷作用和传动链柔性的双馈风电机组时域仿真模型,仿真分析在亚同步、超同步工况下的机组轴系扭振响应,并与理想风载荷作用效果进行比较。结果表明:与理想风载荷相比,随机风载荷作用对机组传动链轴系扭振响应影响明显,且在超同步或亚同步运行时,影响扭振的关键部件为发电机转子。     

冲击载荷下风电机组传动链的振动响应及控制研究

针对极限载荷引起的风电机组功率不稳定问题,对机组传动链在冲击载荷作用下的振动特性及减振控制方法进行研究。以冲击载荷为激励,利用达朗贝尔原理建立传动链的动力学模型,通过多体动力学模型的对比验证,讨论传动链结构参数与其振动响应间的影响关系。在此基础上基于PID控制原理设计被动与主动两种减振方法,并将其应用于某1.5 MW水平轴风电机组模型中。结果表明:相比于结构阻尼系数的影响,轴系刚度系数对传动链冲击振动的影响更明显;在采用两种减振措施后,低速轴上的振动幅值均显著衰减;其中,采用主动减振方法时的减振效果优于被动方法,它在可降低振动幅值1/3的同时增强传动链抑制随机风载荷波动的抗干扰性能。     

基于状态反馈的双馈风电机组传动链动态扭转载荷控制

针对恒转矩控制时传动链阻尼小、扭转载荷大会降低机组传动链上关键部件使用寿命的问题,设计基于状态反馈的传动链动态扭转载荷控制器,使等效在轴上的发电机转速更好地跟踪风轮转速,从而减小低速轴扭矩,实现传动链的动态扭转载荷控制。利用FAST和Matlab/Simulink软件对机组模型和控制器进行联合仿真,结果表明所提出的方法能有效降低双馈风电机组传动链的动态扭转载荷。     

主蒸汽压力变化对机组煤耗率的影响分析

主蒸汽压力是机组实际运行中必须密切监视和调节的主要参数之一,在机组实际运行中会不可避免的偏离设计值,从而影响机组的发电标准煤耗率,影响机组的热经济性和安全性.在火电厂热经济性统一物理模型和数学模型的基础上,根据多元扰动下的热力系统能效分析模型得到主汽压变化对煤耗率影响的计算模型,并以某电厂660 MW机组为例进行验证,并计算了此机组不同工况下主汽压变化对机组煤耗的影响,并绘制成图,对其规律进行了分析.此计算模型得到的计算结果误差较小,足以满足工程实际的需要.     

Comparative study on transient stability analysis of wind turbine generator system using different drive train models

A huge number of wind generators are going to be connected with the existing network in the near future. Therefore it is necessary to analyse the transient stability of power systems, including wind turbine generator systems (WTGS). It has already been reported that one-mass or lumped model of wind turbine system is insufficient to analyse the transient behaviour of WTGS. It has also been reported that for the precise transient analysis of WTGS, a six-mass drive train model is needed. The reduced order models (three-mass and two-mass) have also been adopted so far for transient behaviour analysis. But the transient stability analysis of using six-mass, three-mass and two-mass drive train models has not been reported sufficiently so far in the literature. The authors have conducted an analysis using these methods. First, a detailed transformation procedure is presented from six-mass drive train model to two-mass model, which can be used in the analysis of transient stability simulation with sufficient accuracy. It is then determined which drive train model is appropriate for transient stability analysis of grid-connected WTGS. The effects of drive train parameters (such as inertia constant, spring constant and damping constant) on stability are examined using the above mentioned types of drive train models. Moreover, different types of symmetrical and asymmetrical faults at different wind generator power levels are considered in the simulation analyses with and without considering damping constants in six-mass, three-mass and two-mass shaft models. Considering the simulation results, it can be concluded that two-mass shaft model is sufficient for the transient stability analysis of WTGS.     

Low voltage ride through capability enhancement of wind turbine generator system during network disturbance

The energy capacitor system (ECS), composed of power electronic devices and electric double layer capacitor to enhance the low voltage ride through (LVRT) capability of fixed speed wind turbine generator system (WTGS) during network disturbance, is discussed. Control scheme of ECS is based on a sinusoidal pulse width modulation voltage source converter and DC?DC buck/boost converter composed of insulated gate bipolar transistors. Two-mass drive train model of WTGS is adopted because the drive train system modelling has great influence on the characteristics of wind generator system during network fault. Extensive analysis of symmetrical fault is performed with different voltage dip magnitudes and different time durations. Permanent fault because of unsuccessful reclosing is also analysed, which is one of the salient features of this study. A real grid code defined in the power system is considered and LVRT characteristic of WTGS is analysed. Finally, it is concluded that ECS (20 MW) can significantly enhance the LVRT capability of grid connected WTGS (50 MW) during network disturbance, where simulations have been carried out by using PSCAD/EMTDC.     

水冷柴油机工程车用取力口功率拓展

BFM1015系列水冷柴油机工程车在关重件结构不变的前提下,通过在飞轮壳与曲轴箱结合面之间增加传动箱,实现了功率的倍增。计算分析表明,增加的取力口传动系对轴系的扭振无明显影响,且结构紧凑简单,可靠性高,现已批量投入市场。     

Review on wind turbines with focus on drive train system dynamics

The strong growth within the wind technology market, underpinned by policy goals around the world, has highlighted the demand for advanced engineering analysis to improve wind turbine (WT) design, both in terms of reliability and design of larger turbines. This paper presents a review of the latest research that has been carried out in modeling and analysis of load transmission in WT drive train systems and their components. Common failure roots are elaborated, and probable hypotheses are presented. A modeling approach is derived by classification into engineering, mathematical and computational models with a focus on gearbox modeling efforts. Precise understanding of drive train system dynamics and load transmission is necessary for a cost efficient and robust system design to enhance reliability and reduce the maintenance costs. Design optimization of WTs and their subsystems will make future WTs more attractive compared with fossil and nuclear power plants, and it is therefore an important issue for a more sustainable environment. Copyright © 2014 John Wiley & Sons, Ltd.     

Drive train dynamics assessment and speed controller design in variable speed wind turbines

This paper deals with the speed controller design in DFIG based wind turbines, and investigates stability and performance of the drive train dynamics against different control strategies. It is shown that speed controller design based on the single mass drive train model may result in unstable mechanical modes, because it ignores the dynamics of the flexible shaft. Then, another control approach, known as feedforward compensation of the shaft torsional torque, is examined. It is shown that this control method results in poorly damped oscillations of torsional torque and turbine speed during the transient conditions. The open loop transfer function from the electromagnetic torque to the generator speed contains a dual quadratic function representing the dynamics of flexible shaft. The dual quadratic function comprises resonant and anti-resonant frequencies that greatly affect the stability of the drive train dynamics. Next, a step-by-step procedure for designing the speed controller based on the two-mass drive train model is proposed. The proposed speed controller provides stable closed loop system, zero tracking error, low-frequency disturbance rejection, and open-loop gain attenuation at the resonant frequency. At the end, performance of the proposed controller is investigated by the time domain simulations.     

船用汽轮机直驱式容积控制执行机构仿真及试验

In order to make the actuator of marine turbine miniaturization and integration,as well as to have a better vibration and noise performance,a new actuator has been proposed based on direct drive volume control in this paper and a simulation model has be established with AMESim.The static and dynamic performances and effectiveness have been studied and verified.Simulation and experiment results show that the dynamic response time of simulation model is longer than actual actuator because the worst conditions in the volumetric efficiency of the pump,the throttling loss of valve and the pipeline resistance are considered in the model.However,the simulation result has enough accuracy in view of the difference between simulation result and experiment result being 0.07%,without considering the dead zone,hysteresis and saturation limit of electric elements such as motor and displacement sensor.     

A novel power splitting drive train for variable speed wind power generators

In this paper a novel electrically controlled power splitting drive train for variable speed wind turbines is presented. A variable speed wind turbine has many advantages, mainly it can increase the power yield from the wind, alleviate the load peak in the electrical-mechanical drive train, and posses a long life time, also, it can offer the possibility to store the briefly timely wind-conditioned power fluctuations in the wind rotor, in which the rotary masses are used as storages of kinetic energy, consequently, the variable speed wind turbines are utilized in the wind power industry widely. In this work, on the basis of a planetary transmission a new kind of drive train for the variable speed wind turbines is proposed. The new drive train consists of wind rotor, three-shafted planetary gear set, generator and servo motor. The wind rotor is coupled with the planet carrier of the planetary transmission, the generator is connected with the ring gear through an adjustment gear pair, and the servo motor is fixed to the sun gear. By controlling the electromagnetic torque or speed of the servo motor, the variable speed operation of the wind rotor and the constant speed operation of the generator are realized, therefore, the generator can be coupled with the grid directly. At the nominal operation point, about 80% of the rotor power flow through the generator directly and 20% through the servo motor and a small power electronics system into the grid. As a result, the disadvantages in the traditional wind turbines, e.g. high price of power electronics system, much power loss, strong reaction from the grid and large crash load in the drive train will be avoided.     

齿轮箱弹性支撑对风电机组性能的影响

齿轮箱弹性支撑是风力发电机组的一个很重要的部件,对风力发电机组的动态特性有重要影响。文章通过在Simpack软件中建立风力发电机组传动链的模型,研究弹性支撑对传动链频率的影响。获得弹性支撑对传动链频率的影响关系曲线图。根据风力发电机组坎贝尔图和弹性支撑的强度要求可以得出弹性支撑最低要求刚度,用于弹性支撑的选型．     

1.5MW低风速风力发电机组主传动系统设计及动力学分析

低风速风力发电机组具有广阔的市场前景,其主传动系统的设计和分析是整个风机研发的关键技术之一。通过对风机各种传动系统结构形式的分析、对比和优化,设计了适于1.5 MW低风速风力发电机组的最佳传动方案,即内置式主轴、二级行星加一级平行轴齿轮传动的结构形式。采用多体动力学软件SIMPACK建立了该风机主传动系统的精确模型,找出系统的固有频率及激振源,并进行共振分析;对共振危险点进行时域仿真,根据仿真结果研究振动对风机系统的影响。最后根据系统的动态特性分析结果,验证所设计的主传动系统的可靠性。     

基于改进自抗扰控制的双馈式风电机组传动系统扭振抑制策略

抑制风电机组传动系统的扭振,对于降低系统疲劳载荷、提高机组寿命具有重要意义。文章通过直接控制传动系统的扭角来抑制系统扭振,考虑非线性不确定因素,从功率的角度建立扭角数学模型。由两质量块模型得到功率和扭角的正相关关系,在此基础上,提出一种扭角参考值给定方法。采用改进的自抗扰控制策略补偿传动系统的未知扰动,将系统线性化,并通过非线性状态误差反馈将扭角给定值转化为功率给定值,进而抑制系统扭振。改进自抗扰控制参数调节简单,对扰动补偿更精确,提高了控制器的性能。仿真结果表明,所提出的抑制策略可以明显减小传动系统在阶跃风况和湍流风况下的扭振。