Efficiency Maximization for Half-Bridge LC Converter through Automatic Dead Time Tuning

Induction heating (IH) is becoming the preferred technology for domestic cooktop market. This kind of systems offer a higher efficiency than the standard solutions: electric and gas stove. IH operating condition can vary grandly making it difficult for the power converter to maintain soft switching operating mode. The required dead time for operating zero voltage switching (ZVS) condition, changes too, due to the different load conditions. In this paper a new method for automatic dead-time compensation is presented. Using this new method, soft switching is achieved for every load conditions even under worst case. This allows the converter to always operate in ZVS mode. The main benefits of it are improved effective SOA and efficiency. The method does not require any additional external components since current sensing functions are already implemented for power management purposes. Experimental measurements performed on a commercial Induction cooktop, with ON Semiconductor IGBTs, demonstrate the effectiveness of this method and its robustness with regard to component variations.