Hybrid Resonant Inverter Fed Induction Heating Using Fuzzy Logic Based PWM

The inverters are commonly used for medium power induction heating applications. In the process of induction cooking, a disc of metal is surrounded by a copper coil through which an alternating current is made to flow. The disc has a finite diameter and thickness. It is placed at a given distance from the coil and concentric to it. Secondary current is induced in the disc and this induced current circulates around the outer surface of the disc resulting heating effect. The switching is done at various frequencies to get energy efficient heating. In this paper switching is done using fuzzy logic controller to get the energy efficient heating. The fuzzy logic controller uses the error and the rate of change of error as input and the frequency is fed as output to maintain at the required temperature. The hardware system is developed and fabricated. The fuzzy logic controller is designed and simulated in MATLAB to get the switching frequency. In this paper a inverter where both series and parallel resonant circuits are used for an induction cooking-range with two hot zones. In order to minimize losses, switching is made at zero current crossover (ZCS). Keywords-Induction Heating, Fuzzy Logic Controller, Hybrid Resonant Inverter, switching, cooking appliance.