High-frequency induction heater - has ferrite annular core and winding which produces eddy currents at frequency of power-MOSFET switched resonant DC-AC converter

摘要

The high-frequency section, comprising a Class-E power converter and a ferrite-cored inductor with an air gap into which the workpiece is introduced, is supplied from 220 V mains (2,3) via an interference suppression filter (1), a bridge rectifier (4), a harmonic filter (5) and a galvanic-isolation flux converter (6) with power MOSFETs (29, 30). The pole faces of the air gap are coated with heat-reflecting paste. The power converter is of resonant-circuit type. USE/ADVANTAGE - Esp. for surface hardening of small workpieces. Power in kW region is used more efficiently, and water cooling is superfluous.