Optimised Control for High Frequency Induction Heating Power Sources

The increasing demand for high frequency induction-heating generator technology has a significant impact on cost. The motivation for this research was to realise a robust high frequency generator design with the use of standard low-cost power semiconductor devices, whilst maintaining adequate reliability and control. This paper presents a robust control circuit for high frequency induction-heating power sources, applied to ferrous and non-ferrous metal loads (Q>10). The circuit operates by virtue of the well known swept frequency control (SFC) technique, allowing for the regulation of the output power delivered to the induction heating load. An innovative feature of this control circuit is its ability to continuously monitor the load phase angle whilst maintaining zero voltage switching (ZVS) of the high frequency power converter semiconductors over the entire operating range.