Inductio Heating

Inductio Heating

Induction heating is comprised of three basic factors: electromagnetic induction, the skin effect, and heat transfer. The fundamental theory of IH, however, is similar to that of a transformer. Elec- tromagnetic induction and the skin effect are described in this section. Figure 3-1 illustrates a very basic system, consisting of inductive heating coils and current, to explain electromagnetic induc- tion and the skin effect. Figure 3-1-a shows the simplest form of a transformer, where the second- ary current is in direct proportion to the primary current according to the turn ratio. The primary and secondary losses are caused by the resistance of windings and the link coefficient between the two circuits is 1. Magnetic current leakage is ignored here.

When the coil of the secondary is turned only once and short-circuited, there is a substantial heat loss due to the increased load current (secondary current). This is demonstrated in Figure 3-1-b. Figure 3-1-c shows a system where the energy supplied from the source is of the same amount as the combined loss of the primary and secondary. In these figures, the inductive coil of the primary has many turns while the secondary is turned only once and short-circuited. The inductive heating coil and the load are insulated from each other by a small aperture. The next phase of the skin effect occurring under high frequency is presented in Section 3-2.
As the primary purpose of induction heating is to maximize the heat energy generated in the sec- ondary, the aperture of the inductive heating coil is designed to be as small as possible and the secondary is made with a substance featuring low resistance and high permeability. Nonferrous metals undermine energy efficiency because of their properties of high resistance and low perme- ability......

Induction Heating System Topology.pdf

Induction Heating.pdf