【摘要】 随着大量非线性负荷接入电网,电力变压器铁心更加频繁地工作在谐波、直流偏磁等非标准磁化条件下,传统磁滞模型由于缺少对材料磁化物理机理的深入研究,导致在模拟实际工况下铁心材料磁特性时精度受到限制。本文基于磁光克尔效应磁畴动态观测仪,观察了电工钢片在外磁场磁化过程中磁畴畴壁运动变化,从磁化过程中磁畴运动机理出发,建立了包含有多个磁畴能量的物理模型,并基于总磁能局部最小化原理得到磁畴的磁化状态公式,求得磁畴体积以及磁矩方向的变化。通过测量数据拟合模型参数后,得到电工钢片交变磁化下一系列磁滞回环,并与实验测得结果进行了对比分析,证明该模型能够有效的模拟交变磁化下的磁滞曲线。本文研究结果为进一步实现实际工况下电工设备铁心材料复杂磁特性物理模型的研究打下基础。更多还原

【Abstract】 As a large number of nonlinear loads are connected to the electric grid, the transformer core works in the harmonic, DC bias and other non-standard magnetized conditions more frequently.Due to the lack of in-depth study on the physical mechanism of magnetization of the material, the traditional hysteresis models are reported to have limited modeling accuracy for the magnetic properties of core material running under the actual working conditions. In this paper, based on magneto-optic Kerr effect magnetic domain dynamic viewer, the domain wall movements of the electrical steel sheet during the process of magnetization were observed. A physical model that contains multiple domain energy was established based on the mechanism of magnetic domain movement in the process of magnetization. Further, the formula of domain magnetization state was obtained by means of the local minimization principle of the total magnetic energy, and the change of volume of magnetic domain and the direction of the magnetic moment were computed. By fitting the measuring data into model parameters, a series of hysteresis loops of electrical steel sheet under alternating magnetization were obtained, and by comparing with the experimental results, it is proved that the model can effectively simulate the magnetic hysteresis curves in the alternating magnetization. The research results in this paper lay a foundation for further research in the physical model of ferro-materials in electrical equipment under complex magnetic properties for actual conditions.更多还原