机械应力下取向硅钢片动态损耗特性测量与模拟OA

The grain-oriented(GO)silicon steel sheets,which constitute the core of a power transformer,are inevitably subjected to stress during processing,stacking,and operation.The mechanical stress affects the dynamic loss characteristics of the GO silicon steel sheets.Therefore,it is necessary to conduct relevant research on the dynamic loss characteristics of GO silicon steel sheets under mechanical stress. The existing problems of the dynamic loss model of GO silicon steel sheets under stress can be summarized as follows.Firstly,the current models have a good applicability in simulating the dynamic loss of non-oriented silicon steel sheets under stress.Still,they have poor applicability to GO electrical steel sheets.Secondly,the parameter identification depends on the experimental values measured under a particular stress,which is likely to lead to overfitting.As a result,the errors of the calculated loss under a specific stress are minor,but the errors are substantial under other stresses.Thirdly,it is also necessary to study the stress dependence of eddy current loss and residual loss. Therefore,this paper proposes a dynamic loss model considering the stress effect for GO silicon steel sheets.A measurement platform is set up.The magnetic properties and dynamic loss characteristics of soft magnetic materials under mechanical stress are measured,as well as the static hysteresis and dynamic loss characteristics of GO silicon steel sheets.Based on the energetic model,taking into account the stress-induced additional energy,the magnetic field strength under stress can be expressed as the superposition of the magnetic field strength without stress and the stress-induced additional magnetic field strength.The stress-induced additional magnetic field strength accounts for the effects of the same stress on different magnetic densities and the nonlinear effects of stress.Therefore,the static hysteresis model,which considers stress,can simulate the static hysteresis loss of GO silicon steel sheets under various stresses.The electrical conductivity only depends on the composition of the material itself.Thus,the influence of stress on the eddy current loss of GO silicon steel sheets can be ignored.Subsequently,considering that stress changes the structure of magnetic domains within GO silicon steel sheets,the relationship between the residual loss parameter V0 and the stress is analyzed.Accordingly,the residual loss under different stresses can be calculated,and the dynamic loss of GO silicon steel sheets under different stresses can be obtained. Experimental verification indicates that the dynamic loss errors of the GO silicon steel sheets with two different grades are both within 10%,which verifies the effectiveness and applicability of the proposed model.The proposed model does not exhibit easy overfitting problems in parameter identification and can accurately calculate the dynamic losses of GO silicon steel sheets under various stresses.