Nonplanar Overlapped Inductors Applied to Domestic Induction Heating Appliances

Abstract

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 non-planar 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. The paper includes the FEM modeling of the non-planar coil, an analysis on the conductor's losses and an experimental verification.

Induction Heating of Two Magnetically Independent Loads With a Single Transmitter

“…The design process goes as follows. In order to be able to deliver 3000 W with near constant PR t , the system must have a global resonance at higher frequency than receiver resonance and the equivalent resistance needs to satisfy V 2 o,rms /R eq > 3000 W at global resonance [16], where V o,rms is the inverter output rms voltage. The half-bridge inverter uses a small DC bus capacitor, so its output voltage will essentially modulate the rectified mains voltage: V o,rms = √ 2/πV mains,rms .…”

“…Whereas previous coupled inductor systems in [12], [14], [16], [18] actively feed all inductors, the proposed system's receiver will not have an internal power source or external cables. Therefore, its only means to heat the top load will be the magnetic coupling with the inductor of a conventional induction heating cooktop.…”

Printed Circuit Board Coils of Multitrack Litz Structure for 3.3-kW Inductive Power Transfer System

“…The more usual and popular WPT technology at short-medium distances is the Inductive Power Transmission (IPT) whose key elements are the transmitter and receiver coils, together with the flux concentrator, [1], [2]. Among the most relevant applications at short distances the following can be mentioned: the implementation for induction heating, [3], [4], wireless power supply for medical implants, [5], [6], and static or dynamic charging of electric vehicles, [7], [8], [9].…”

Proposal and Challenge of Halbach Array Type Induction Coil for Cooktop Applications

“…Further, since the inductance can be reduced by frequency increase, the amount of coil used can be reduced. In addition, a multi IH-coil structure in which large number of small-diameter IH-coil are arranged has been proposed in order to deal with the pot layout-free system [20]- [27]. A technology aimed at cost reduction by PCB coil structure has also been reported [28].…”