考虑输入变量随机性的换流变压器铁心模态频率计算及其方差分析

Modal Frequency Calculation of the Converter Transformer's Core Considering the Randomness of Input Variables and Analysis of Variance

当结构的某一模态频率与其受迫力的频率相接近时,会引起结构的共振,因此需科学地计算结构的模态频率;文中以一换流变压器铁心为研究对象进行模态仿真,考虑铁心材料属性和边界条件这些输入变量的随机不确定性,经中心合成设计抽样法获得其输入变量的样本集,再通过响应曲面模型建立起各阶模态频率与各输入变量间的函数表达式,用该函数代替铁心模态频率仿真结果,通过蒙特卡罗模拟法获得各阶模态频率的统计参数,以及其概率灵敏度分析,并对该响应曲面模型函数进行方差分析。

When a certain modal frequency of the structure is close to the driving force＇s frequency, the structural resonance will happen. It is necessary to scientifically calculate the modal frequency of the structure. With a converter transformer core as the research object of the modal simulation, considering the random uncertainty of the core＇s material properties and the boundary condition, a sample set of the input variables was obtained by using of the central composite design method. The response surface model was chosen to establish the function expression between modal frequencies and input variables, which is used as a surrogate of the modal frequency simulation result of the core. Monte-Carlo method was used to obtain the statistical characteristic of the modal frequency, and probability sensitivity analysis was performed, and the variance analysis for the response surface model function was done.