Rigorous Electromagnetic Analysis of Domestic Induction Heating Appliances

In this paper the developed analytical electromagnetic model of induction heating system is presented. The model was built up assuming equivalent electric and magnetic currents flowing in each planar element of the typical structure used for an induction heating system: the load disk represents the pan steel bottom, the copper inductor, and ferrite flux conveyor. A system of integral equations system was then obtained enforcing the boundary conditions on each element of the structure for the electric and magnetic fields, produced by the equivalent currents. The numerical solution of the system is a matrix equation with a known voltage vector in the left-hand side, and product of impedance coefficients matrix and unknown electric and magnetic currents vector in the right-hand side. Since the feeding voltage is known, and impedance coefficients are calculated using of geometry and material parameters, currents vector can be also calculated. Thus, the whole model is solved and it gives a detailed picture of currents distribution in the system, which in its turn allows to analyze heating process in the load. Each step of developing of the model was verified by appropriate experimental measurements. Achieved results give a possibility to analyze and develop improvements to increase efficiency, safety and to reduce the cost.