Automatic frequency control of an induction furnace

Abstract

The development of an automatic frequency control system for a miniature high frequency induction furnace is described. A background study into the fields of induction-heating, resonance, power electronic resonant converters and phase locked-loops are performed with relevance to this research. An analysis of the resonant load circuit is performed by means of a combination of measurement and numerical simulations. The study of the load behavior and power source is used as a :001 to aid effective implementation of the automatic frequency control system. This Jimulation data is used to detenninc the operating frequency range of the RLL system. A background study is performed in whieh several frequency-control schemes for power electronic converters are investigated. A brief summary, in which the basic requirements for a frequency control system with regards to this research are presented. Two revisions of the Automatic Frequency Control system (RLL) were implemented, on the induction furnace. Experimental results on both systems (Revl and Rev2), illustrating the necessity for frequency control are also presented. Future suggestions for optimizing the loop performance are presented. Further steps in the developmental process of the miniature high frequencj induction furnace are also discussed.