Electromagnetic Modeling and Analysis of Multimaterial Cookware for Domestic Induction Heating

The performance of induction cooktops (inductor and electronic power converter) is closely related to the inductive properties of the cookware used. Traditionally, they are designed to work optimally with fully ferromagnetic cookware. However, multimaterial cookware with a bottom surface composed of a ferromagnetic material and small pieces of aluminum are nowadays more commonly used. Designing cooktops to also work optimally with this cookwares requires identifying the equivalent parameters,
$R_{\text {eq}}$
and
$L_{\text {eq}}$
, obtained from the electromagnetic models of the inductor-load system. Modeling multimaterial cookware, with a large number of inserts, complicates the model design and increases its computational cost. This work presents an equivalent model for multimaterial loads that allows the evaluation of the inductor performance and obtaining the equivalent parameters quickly and accurately. The multimaterial cookware is modeled as a disk of uniform material with equivalent electromagnetic properties,
$\mu _{\text {r,eq}}$
and
$\sigma _{\text {eq}}$
, which depend on the properties of each material and the proportion of area they occupy. The equivalent model has been validated by electromagnetic simulation using a FEA tool and by experimental results. Finally, based on the results obtained, an analysis has been carried out to evaluate the importance of design factors such as the choice of the cookware base material and the size, arrangement, and number of inserts.