Automatic variable frequency asymmetrical control of half-bridge series resonant inverters for low-cost domestic induction cooking

This paper presents a digital implementation of power control for induction cooking appliances with domestic low-cost vessels. The proposed control strategy is based on the asymmetrical duty-cycle with automatic switching-frequency tracking control employing a digital phase locked-loop (DPLL) control on high performance microcontroller. With the use of a phase locked-loop control, this method ensures the zero voltage switching (ZVS) operation under load parameter variation and power control at any power levels. Experimental results have shown that the proposed control method can reach the minimum output power at 15% of the rated value.