Asymmetrical control with phase lock loop for induction cooking appliances

This paper presents an asymmetrical control with phase lock loop for series resonant inverters. This control strategy is used in full-bridge topologies for induction cookers. The operating frequency is automatically tracked to maintain a small constant lagging phase angle when load parameters change. The switching loss is minimized by operating the IGBT in the zero voltage resonance modes. The output power can be adjusted by using asymmetrical voltage cancellation control which is regulated with a PWM duty cycle control strategy.