RESONANCE INVERTER FOR INDUCTION HEATING WITH STABILIZATION OF THE LOAD POWER

Abstract

This paper presents voltage source inverter for induction heating applications, which is char- acterized by the power control based on of fixed-frequency. Induction heating is an important enabling tech- nology. Induction heating technology is nowadays the heating technology of choice in many applications due to its advantages regarding efficiency, fast heating, safety and accurate control. The output power stage of the proposed converter consists of a single-phase voltage inverter using four IGBTs. The power control is achieved by varying the shape of the voltage up applied to the resonant circuit. This power control strategy allows the inverter to work close to the resonance frequency for all output-power levels. The control princi- ples of the pro-posed method are described in detail and its validity is verified through simulated results. The inverter system is designed and the simulation is done using Matlab. The simulation results of are presented. The process of load power stabilization is demonstrated when both active and full load resistance changes. The output current has a sinusoidal form, the harmonic distortion factor of which is less than 2%. With this circuit, an important improvement of the inverter efficiency is expected at high-frequency working condi- tions.