Power control of induction heating inverse power supply

This paper has proposed an improved pulse frequency modulation (PFM) method aiming at the problem of low modulation precision, and insensitive reaction as for the power control of induction heating power supply. This method has combined the PFM control and the digital constant angle phase-lock control. In this paper, digital phase-lock control method is designed to constrict the phase angle and the analysis and deduction of the instable condition is conducted based on the PIC18F4520 and CD4046. The comparative experiments based on the designed model machine are conducted, the results of which has shown that the designed model machine of improved PFM power control method has achieved to improve the control precision and reliability of series resonance induction heating inverse power working at weak inductance states.