Nonplanar Overlapped Inductors Applied to Domestic Induction Heating Appliances

Domestic induction heating appliances are evolving from surfaces with three to five fixed cooking areas to flexible cooking zones. These are able to adapt to a number of vessels of any size and shape by using multiple coils. Some state-of-the-art induction systems make use of overlapped inductors in two layers, which combine the high efficiency of large inductors with the high flexibility of small adjacent coils. The main drawback of this concept is the unequal distance between different coils and the vessel, which implies that each coil presents a different impedance depending on its layer. This paper presents an induction system conformed by nonplanar inductors. These inductors are designed in such a way that they can be assembled in overlapping structures, while preserving equivalence among them, i.e., they all present the same impedance. This paper includes the finite-element method modeling of the nonplanar coil, an analysis on the an experimental verification.