INDUCTION HEATING APPARATUS UTILIZING OUTPUT ENERGY FOR POWERING SWITCHING OPERATION

摘要

"Induction Heating Apparatus Utilizing Output Energy for Powering Switching Operation" An induction heating apparatus comprises a rectifier (2) for rectifying A voltage from an AC mains supply, a resonance circuit formed by an induction heating coil (4) and a capacitor (4), a semiconductor switching device (6) connected in circuit with the resonance circuit to the output of the rectifier, a diode (7) coupled in anti-parallel relationship with the switching device (6), and a circuit (17; 117, 118) for driving the switching device into conduction at a controlled frequency. Further provided is a transformer (14) which derives a low frequency energy from the AC mains supply (1). A second coil (9) is electromagnetically coupled with the heating coil (4) for deriving a high-frequency energy. The low- and high-frequency energies are coupled by diodes (10, 11, 15, 16; 132, 133) to the driving circuit to provide power neccesary to effect the conduction of the switching device.