Abstract
This paper presents the description and analysis of a half-bridge IGBT inverter suitable for heating ferromagnetic materials at high-frequency. The series-parallel scheme is adopted and, an optimum mode of operation is selected which results in a maximum current gain and practically no voltage spikes in the devices at turn-off. Using the state variable approach, the inverter system circuit model was analyzed including the effect of branch stray inductances and snubber components.
The actual performance was tested on a 50-150kHz prototype rated at 6kW. The developed hybrid inverter is characterized by its simplicity of design and operation, yet is versatile in performance. Experimental evidence is presented to confirm the validity of the inverter system model.
Also, an analytical model for the long billet-short coil induction heating geometry is briefly described. The resulting expressions for the induction heating load parameters are obtained in the form of rapidly converging series. The theoretical results obtained have been experimentally verified.
