Measuring the Magnetic Characteristics of Soft Magnetic Materials for Non-Sinusoidal Periodic Excitations

This article deals with the modeling of the characteristics of soft magnetic materials which are exposed to magnetic fields that show a non-sinusoidal but periodic time course. Like materials are very often used in the field of energy conversion, e.g., in electrical machines or transformers, and are typically characterized by their initial magnetization curve and loss data obtained for a sinusoidal change of the flux density defined by its magnitude and frequency. Based on the available data empirical equations were developed for estimating the losses associated with an arbitrary periodic change of the magnetization state in the materials. However, at present available techniques usually only allow for a coarse approximation of the losses in ferromagnetic materials. This article is about the comparison of measurement results and state-of-the-art modeling of the iron losses for non-sinusoidal but periodic flux density characteristics. It covers the design and control of the measurement setup and common specimen shapes, a detailed description of the usually applied modeling strategy, and a comparison of measurement results and empirically estimated iron losses for selected non-sinusoidal periodic excitations.