纳米晶铁芯的介观高频饱和机理与双尺度耦合建模方法

With the development of modern power system, the mathematical modeling problems of nanocrystalline core under high frequency saturation condition is becoming more and more serious due to lacks of fundamental research. Therefore, the key scientific issues associated with high frequency saturation mechanism of nanocrystalline core in mesoscopic scale is focused, as to explore the coupled modeling method based on the correlation characteristics between mesostructure and macroscopic soft magnetic properties. In allusion to two kinds of high frequency magnetic field, "dynamic saturation field" and "static saturation field", the magnetic torque movement rule of nanocrystal and residual amorphous phase is revealed, followed by the influence mechanism of volume fractions of different residual amorphous phase on non-uniform magnetization. Both the topology of magnetic circuit and the calculation method of magnetic permeance within a single domain are proposed, as to establish the equivalent magnetic circuit model in mesoscopic scale. The macroscopic distributed parameter magnetic circuit model of anocrystalline core is established after the research of macro-working points changing mechanism for nanocrystalline core under high frequency saturation condition is proposed. According to the coupling transmission theory, the collaborative working interface between mesoscopic scale and macroscopic scale is studied, then the coupled model of nanocrystalline core in dual-scale is established. The proposed research of this project meets the application requirements of nanocrystalline soft magnetic materials to develop high frequency electromagnetic equipments, the achievements of which will enrich the theoretical foundation and analytical methodology for equivalent modeling of nanocrystalline core under high frequency saturation condition, with both theoretical significance and application potentials.

随着现代电网的发展，纳米晶铁芯在高频饱和工况下的建模问题由于缺乏基础研究而变得越来越突出。本项目从纳米晶铁芯的介观高频饱和机理入手，探寻基于介观结构与宏观软磁性能关联特性的耦合建模方法。针对"动态饱和"和"静态饱和"两种高频磁场，分析纳米晶粒与残余非晶相的磁化磁矩进动规律，研究不同残余非晶相体积分数对非均匀磁化的影响机制，提出单磁畴介观结构的磁路拓扑和磁导计算方法，据此建立介观尺度等效磁路模型；研究两种高频饱和磁场激励下的纳米晶铁芯宏观工作点变化机理，建立宏观分布参数磁路模型；基于介观与宏观变量的耦合传递，研究双尺度间的协同工作界面连接方法，建立纳米晶铁芯双尺度耦合模型。本项目研究适应纳米磁材料在新型高频电磁装备发展的应用需求，其研究结果将丰富高频饱和工况下纳米晶铁芯等效建模的理论基础和分析方法，具有重要的理论意义和应用价值。

纳米晶铁芯在高频饱和工况下的建模问题由于缺乏基础研究而显得愈加突出。本项目旨在从纳米晶铁芯的介观高频饱和机理入手，探寻基于介观结构与宏观软磁性能关联特性的耦合建模方法，解决高频饱和条件下纳米晶软磁合金建模问题，促进纳米新材料在电力系统中的应用。研究内容分为以下三个方面：介观高频饱和机理、磁特性试验和双尺度耦合建模。基于纳米晶铁芯微磁学建模的理论基础，构建了介观尺度下的微磁学仿真模型。首先，针对“静态磁场”，研究了合金磁化与反磁化的两个动态过程，且均以磁矩旋转及磁畴壁位移为主导机制。其次，针对“动态饱和”与“静态饱和”两种高频饱和磁场，分别研究了纳米晶粒与残余非晶相的磁化磁矩进动规律，获得了频率和直流偏磁对合金高频饱和特性的影响机制，包括当直流偏磁为零且交变场强度一定时，复数磁导率随着频率的变化规律；以及当外加交变场保持不变时，外加偏置磁场对复数磁导率的影响。分别从宏观和介观角度揭示了频率对合金磁化速率的影响。根据爱泼斯坦测试法，针对纳米晶、非晶和铁氧体三种不同材料的磁芯开展了宏观高频磁特性试验，得到了三种材料在不同频率范围内的高频基本磁化曲线。结果表明，随着频率的不断升高，饱和磁感应强度有所下降，但纳米晶合金下降最慢，其宏观高频磁性能优于其它两种材料。基于介观与宏观变量的耦合传递，研究双尺度间的协同工作界面连接方法，为建立纳米晶铁芯双尺度耦合模型提供了理论基础。本项目的研究结果可进一步丰富纳米晶铁芯特殊工况下等效建模的基础理论、分析方法与创新技术，具有重要的理论意义和应用价值。