Induction heating cooking appliances are powered by a single-phase utility AC whose frequency and phase may change depending upon geographical and operating conditions. This information is required to compute important operational parameters of the resonant converter as well as to comply with harmonic emissions standards. This paper presents a digital circuit that provides in real-time information about the frequency and phase of the full-wave rectified voltage of a half-bridge series-resonant inverter for induction-heated cooking appliances. The proposed technique and its digital implementation is detailed. Simulations are performed to confirm the validity of the proposed technique and, finally, the digital circuit is implemented in a system-on-chip (SoC), and the technique is experimentally verified in a prototype.
