Iron-loss Calculation of Inductors Considering Non-uniform Flux Density Conditions

Abstract

Owing to the significant advances made in the field of power semiconductor devices, such as SiC and GaN, the switching frequency of power converters has been increased. Thus, the volume of passive components such as filter inductors and transformers can be reduced. However, the reduction in the heat-dissipation surface area of inductors results in a considerable increase in temperature, which is a constraint for increasing the power density of power converters. To prevent these problems, the iron-loss evaluation of inductors is one of the most important issues in realizing high-power-density converters. This paper presents an accurate iron-loss calculation method for inductors considering the non-uniformity of the flux-density distribution in the magnetic core. First, it is verified that the non-uniformity of the flux-density distribution in the core results in the deviation of the iron-loss measurement even when the same magnetic material is used in the core and when the inductor is excited under the same excitation condition. Next, the procedure to obtain the iron-loss data, which describes the relationship between the iron loss and excitation condition more precisely, is introduced. Finally, a method to accurately calculate the iron loss in an inductor using electromagnetic simulation and more precise iron-loss data is introduced. method is verified using a toroidal core and a UU core under sine voltage condition and rectangular voltage condition.