Impedance d'un four a induction : definition, theorie et calcul

Abstract

The problem evoked here originates in concerns about optimal control of induction heating devices. There seems to be two separated topics there : analysis of the furnace system proper (leading to the knowledge of how its impedance changes in time) and control of the alimentation system (using such an impedance characteristic as data). This conceptual separation of the problem into two parts has obvious advantages, but depends on a workable definition of the concept of impedance. The aim of this paper is thus to give a variational formulation of the eddy-currents computation problem, from which such a definition can be derived. Next we examine how the computation of the impedance can be simplified in the case of actual induction heating devices, where skin-effect is often present.