Line-Frequency Noise Suppressor to Reduce Audible Noise in Induction Heating Systems

Abstract

Induction heating (IH) technology is widely used in domestic applications due to its high heating efficiency and environmentally friendly operations. Heating performance for high-power operations with weakly magnetic-coupled vessels has improved user convenience. However, those require high-power operation of resonant inverters, which induces large resonant current, resulting in audible noises caused by the line frequency. This paper proposed an IH system operating with a line-frequency noise suppressor (LNS) to attenuate the audible noise of the line frequency. The LNS handles only partial power, offering a cost advantage and an alternative solution to reduce the audible noise. The proposed IH system employing the LNS is experimentally verified with a 1.8 kW half-bridge IH inverter and LNS circuit prototypes.