摘要
可靠性是度量产品质量的重要指标。努力提高产品的质量可靠性,不仅可以防止故障和事故的发生,尤其是灾难性事故的发生,而且可以避免产品开发时频繁的“事后更改”现象,从而缩短开发周期、节约开发成本、降低维修费用和其他由于可靠性不高而产生的附加费用。因此,可靠性成为各国科研机构和学者致力研究的重点和热点。随着风力发电机特别是大中型风力发电机容量的增加,为实现其优异的性能,其结构越来越复杂,从而带来的主要问题之一是故障率提高。因此对风力发电机而言,在设计时,除了要考虑其功能性、工艺性、时间性和经济性外,还必须考虑其可靠性。本文以动量理论、叶素理论、片条理论为基础,给出了风力机气动性能计算方法,并结合实际情况计算出了1.0兆瓦变桨距风力发电机塔架的所受载荷。通过有限元方法对塔架做了静态分析和动态特性分析。
风力机叶片可靠性分析部分介绍了风力机叶片在挥舞方向上的疲劳载荷下可靠度分析方法。疲劳载荷下可靠度分析方法考虑了风速的分布,疲劳载荷的长期分布,叶根部的S ? N曲线和材料的分散性等情况,应用一次二阶矩的分析方法得到叶根在挥舞方向上的疲劳可靠度。
可靠性估计部分在目前利用Bayes方法进行模糊可靠性分析研究的基础上,提出了比较完整的模糊Bayes可靠性预测的方法。并通过实际的算例计算了风力发电机的模糊可靠度的估计区间。
本文通过塔架静态分析结果得出塔架高度和应力的关系,由塔架动态分析结果得出基础刚度和一阶频率的关系,以及塔架的低阶固有频率避开了风力发电机的额定工作频率。验证了采用模糊Bayes方法来计算风力发电机模糊可靠度是可行的。
Reliability is a measure of an important indicator of product quality. It can prevent breakdowns and accidents, especially the occurrence of catastrophic accidents through improving the quality of the product reliability. Thus, it can save development costs, reduce maintenance costs and other additional costs arising due to reliability is not high. Therefore, the reliability is increasingly becoming research focus and hot spots for national research institutions and scholars. With the ncreasing of wind turbine, its structure is designed more complex in order to achieve its excellent performance.Thus, the failure rate in the design is improved due to the more complex structure.In the terms of wind turbine, it not only considers the functionality, process, timeliness and economy, but also must consider its reliability in the design.
In this paper, the method calculating the aerodynamic performance of wind turbines are given based on momentum theory, blade element theory and strip theory.And the loads of the 1.0 MW variable pitch wind turbine tower under actual situation is calculated. The static analysis and dynamic characteristic analysis of tower are analysed through the finite element method.
The section of the wind turbine reliability analysis introduces the method for evaluation the reliability of the wind turbine blade against fatigue load. The first order reliability method is applied to perform a reliability analysis of the wind turbine blade.
A fairly complete fuzzy Bayes reliability of forecasting methods are introduced based on Bayes method in the current use of fuzzy reliability analysis. And through practical example of wind turbines is calculated estimates of fuzzy reliability interval.
In this paper, the relationship between tower height and stress is obtained through the result static analysis of tower. And the relationship between foundation stiffness and a first order frequency as well as the tower's low-level natural frequency avoids wind turbine rated operating frequency are obtained through the result of dynamic analysis of tower. Verified the feasibility of using fuzzy Bayes method to calculate the fuzzy reliability of wind turbine.
引文
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