The widespread adoption of induction heating in diverse applications, owing to its non-contact and efficient heat generation characteristics, is evident in domestic cooking and various industrial processes like welding, annealing, melting, and surface hardening. This paper delves into the realm of induction cooking, focusing on multiple loads powered by suitable converters and controlled through effective techniques. The proposed configuration centers on a 3-leg full-bridge resonant inverter, enabling the simultaneous heating of three distinct material vessels with independent power control for each load. Operating the three induction heating loads at their respective resonant frequencies allows for the simultaneous heating of vessels made of iron, steel, and aluminum. An asymmetric duty cycle control technique is employed to regulate the output power independently for each load. Frequency parameters for this application span from 20-30 kHz for low frequency to 100-500 kHz for high frequency, with a power ratio of 70% for low frequency and 30% for high frequency. This configuration facilitates simultaneous and independent control of different frequency currents, incorporating zero voltage switching (ZVS) operation. The 3-leg full-bridge resonant inverter configuration consists of three legs within a single full-bridge inverter, each operating at different frequencies: low, medium, and high. Controlled by an asymmetric duty cycle technique, each inverter is associated with a load resonant circuit comprising three series resonant circuits for low, medium, and high frequencies. This setup enables independent control of currents at different frequencies, allowing for desired power ratios through duty-ratio control. This proposed configuration streamlines the design and control processes while accommodating high-power applications. Although the inverter output combines three frequencies, each load only allows its respective resonant frequency current. Zero voltage switching is achieved for the switching devices in each inverter leg during higher duty-ratio instants. The output power is predominantly composed of the low-frequency component, minimizing switching losses for the low-frequency inverter leg. The design and simulation of the 3-leg full-bridge resonant inverter configuration are conducted using MATLAB/Simulink, showcasing its feasibility and effectiveness in the context of induction cooking applications.

Power converters, Induction heating, 3-leg full-bridge resonant inverter, Induction cooking, Different material vessels, independent power control, Resonant frequencies, Asymmetric duty cycle control.