An improved LLC resonant inverter for induction heating applications

This paper proposes a LLC resonant load configuration of a half bridge inverter for induction heating applications. The proposed topology, based on the series-parallel half-bridge resonant inverter is described. It can operate with zero-voltage switching (ZVS). At the resonant frequency, the secondary current is amplified over the heating coil with small switching angle, which keeps the reactive power low and permits heating with small current through the resonant inductor and the transformer. The operation and control principle of the proposed high frequency inverter are described and verified through simulated and experimental results.