Converter for Inductive Billet Heating on Extrusion Plants

This converter design is a parallel resonant circuit converter with transistor technology.

This converter design was developed in-house in the year 1999 to control a billet heating system with four coil sections.
The goal of this development was to apply a so-called temperature wedge to the billet being heated, in order to heat the end of the billet facing the extrusion die more intensely.

Until then, this temperature wedge was applied by switching off the individual coil section with a time delay, as the existing technology did not allow for continuous power control of the individual coil section.

The prototype we developed in 1999 was put into operation shortly after commissioning in three-shift production at a then-German manufacturer of aluminum extrusion profiles and is still in operation today. It was the pioneer for a new generation of billet heating.

The converter can be equipped with HSG technology.

Advantages:

• Continuous power control of individual coil sections
• Wear-free, without high current contactors
• Gentle handling of the resonant circuit capacitors, no short-circuit current load

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