Input Voltage Selection Method of Half-Bridge Series Resonant Inverter for All-Metal Induction Heating Application Using High Turn-numbered Coil

Abstract

All-metal induction heating (IH) systems have been presented to heat both ferromagnetic and non-ferromagnetic pots using dual resonant frequencies. They are designed for heating the ferromagnetic pots using a first-harmonic operation mode (FHOM) and for heating the non-ferromagnetic pots using a third-harmonic operation mode (THOM). The all-metal IH systems employing the dual resonant frequencies consist of an IH inverter and a power factor correction (PFC) circuit to transfer the desired power to the pots by increasing the input voltage of the IH inverter. In this paper, the input voltage is designed to obtain an efficiency-optimized operating point. To obtain the appropriate input voltage, power loss analyses are conducted using the first harmonic approximation (FHA). Based on the analysis results, the input voltage of the IH inverter can be selected to improve the power conversion efficiency of the IH inverter. A 2-kW half-bridge series resonant inverter prototype is implemented to verify the effectiveness of the proposed design by heating the ferromagnetic pots using the FHOM with 2-kW transfer power and by heating the non-ferromagnetic pots using the THOM with 1-kW transfer power.