Analytical Loss Model for Magnetic Cores Based on Vector Magnetic Circuit Theory

Abstract

Currently, some empirical formula methods, such as the Steinmetz equation, have been widely used in calculating high-frequency magnetic core loss. Although these methods may provide satisfactory accuracy under some certain conditions, they not only cannot present clear physical interpretation and fail to account for the origin and variation of losses, but also offer much lower accuracy for wide operation ranges. In this article, a new analytical model is proposed for the first time to predict core loss by the new vector magnetic circuit theory. In addition to reluctance, two new components, i.e., magductance and hysteretance are proposed in the vector magnetic circuit, which are used to describe the eddy-current loss and the hysteresis loss, respectively. Thus, the clear physical significance is available with the proposed loss model. Given the geometrical and physical parameters of cores, the loss can be predicted. Furthermore, the uneven distribution of magnetic flux inside the magnetic core is characterized by parallel vector magnetic circuits. By comparing with the available empirical formulas, it has been proven that the proposed analytical model not only offers clear physical concepts, but also has much higher accuracy.