EMI improvements using the switching frequency modulation in a resonant inverter for domestic induction heating appliances

In this paper the spread-spectrum technique is applied to a resonant half-bridge inverter for domestic induction heating in order to improve the electromagnetic interference (EMI). This technique has been successfully applied in switching mode power supplies (SMPS). Two different switching frequency modulation strategies are tested and the influence of different modulation parameters is analysed. Both simulation and experimental test bench including inverter and measuring instrumentation are presented. The simulated instruments and detectors are based on homodyne receiver. Finally experimental measures are compared with simulation results.