A measurement method for the characterization of the ferromagnetic bottom layer of cookware used in domestic induction heating

Design-oriented modeling approaches, such as finite element analyses (FEA), rely on accurate material data. However, manufacturers rarely provide the necessary data for cookware used in domestic induction heating. Due to the multi-layered structure of the cookware bottom, conventional measurement methods for the characterization of magnetic material are not applicable without great effort in preparation of suited material specimen. This contribution proposes a novel measurement method that allows determining the electromagnetic properties of the ferromagnetic bottom layer of cookware. The proposed measurement method is based on the minimization of deviation between measurement and simulation data in dependence of material properties. By characterization of the ferromagnetic bottom layer of a material specimen made from multiple layers, the feasibility of the method is shown. The results presented for the magnetic material characterization are validated using Epstein frame measurements. It is shown that the deviation between the magnetization curve determined with the proposed method and the tip of the hysteresis curve measured using the Epstein frame is approximately 3 %. To validate the results presented for the specific electrical resistance, a microhmmeter is used. The relative error between both measurements is approximately 16 %.