考虑不同时间尺度的风电变流器功率模块可靠性评估模型

考虑到变风速运行下风电变流器功率模块的结温波动既受到风速的影响,同时也存在由换流引起的基频结温波动。为了综合衡量这两个时间尺度下结温波动对变流器可靠性的影响,提出考虑不同时间尺度下结温波动特点的可靠性评估模型。针对受风速影响较大的长时间尺度结温波动,根据FIDES可靠性评估导则,引入热应力因子和温度循环因子对不同风速均值、风速湍流强度运行状态下的可靠性影响进行评估。针对由换流引起的短时间尺度下的基频结温波动,采用多状态概率评估思想将风速大小进行概率划分,并基于功率模块失效机理评估不同风速对功率模块故障率的贡献。最后,以某风场变流器为例,对其可靠性进行评估,并分析设计参数对可靠性的影响。文中结论对于制定检修计划,提高功率模块设计可靠度提供了依据。

Multi-time Scales Reliability Evaluation Model of Power Modules in Wind Power Converter

Under variable wind speeds operation , the power modules of wind power converters suffered different time-scales of junction temperature variations;the long-term junction temperature variation caused by series changed wind speed time , as well as the short-term fundamental frequency junction temperature variation caused by working commu-tation.In order to generally estimate the reliability effect of long-term and short-term junction temperature , a multi-time scales reliability evaluation model has been developed in this paper .As with long-term junction temperature vari-ation, thermal factor and thermal cycling factors have been introduced based on FIDES guide and the effect of wind speed and wind turbulence have been evaluated .As with short-term junction temperature variation , multi-states evalu-ation philosophy has been adopted , and the wind speed distribution has been allotted to address the different effects to power module reliability .Finally , taking a real field wind power converter as example , the reliability has been as-sessed and the effects of design parameters have been analyzed .The achievement of the research would prove useful reference for the enhancement of wind power converter reliability .