Soft switching inverter with resonance tracking control using quasi variable capacitor

Induction heating (IH) appliances are widely used for industrial appliances and home electronics because IH has a lot of merits. Recently, wireless power transfer attracts attention as a promising industry. As for wireless power transfer, inductance is changed in accordance with power transmission distance or surrounding environment. Similarly as for IH, inductance and resistance as equivalent circuit parameters is changed in accordance with heating temperature. For this reason, a transmission efficiency and a heating efficiency is lowered with changing these parameters. Therefore the power supply for these applications with resonance tracking control is proposed in this study. The feature of this power supply is the ability to track resonance at constant frequency. In this paper, an analytical study of the proposed power supply is performed and the results derived from analysis are presented.