Topology Study for an Inductive Power Transmitter for Cordless Kitchen Appliances

In a conventional kitchen an appliance may require over 2.4kW of power during normal operation. In a cordless kitchen the used appliances are cordless, so this power needs to be transferred over a distance of at least 4cm, at high efficiency. Therefore an inductive power system needs to be installed with an inductive power transmitter below the table countertop and an inductive power receiver inside the appliance. Next to the inductive power system the cordless appliance is also equipped with a communication channel. There are many transmitter topologies which can satisfy the functional requirements (like amount of power transferred, high efficiency, etc.) of the inductive power system. But satisfying the non-functional requirements (like EMI) most often takes several design iterations. Presently, a transmitter based on a series resonance principle will be the first choice of the designer because it is relatively simple to understand and can satisfy the functional requirements of the system easily. The aim of the paper is to describe the present choice for the transmitter and to explain a new transmitter topology that can intrinsically minimize the problems associated with the present choice. The paper proceeds with a brief introduction about the cordless kitchen concept, in section I. Section II gives the description and analysis of the presently used topology in the system. The requirements of a new transmitter topology are explained in section III and a new transmitter topology along with its analysis, is proposed in Section IV. Section V explains the experimental measurements and gives the comparison between the present and the proposed topologies. The conclusion is stated in section VI.