High Frequency Soft Switching Dual Mode Resonant Converter with SW/PDM Control for Improved Efficiency of Domestic IH Applications

Blessy. C. Kayyalath; Teena Jacob

Abstract: Domestic Induction Heating (IH) systems are based on a dc-link resonant converter which supplies high frequency currents (20-100 kHz) to an inductor, which heats up the pan. In resonant converters, maximum output power and efficiency occurs at the resonant frequency, and the switching frequency is increased to reduce the output power. It results in increased switching losses and lower efficiency in the low-medium-output power range. Thus class-D/DE dual-mode-operation resonant converter is proposed to achieve higher efficiency in a wide output power range. In such converters, resonant capacitors are replaced with electromechanical relays in order to change the operation mode. Class-D half bridge converter with square wave( SW) control is used in the high output power range, whereas class-DE half-bridge converter with pulse density modulation (PDM) is used in the low to medium output power range. The combination of these operation modes achieves high efficiency levels in a wider range of output power levels. The dual-mode resonant converter is simulated using MATLAB/SIMULINK. Class D/DE dual mode resonant converter operation is a cost-effective procedure for the entire improved efficiency of the cooking process.

Keywords: induction heating (IH), resonant converter, square wave control (SW), pulse density modulation (PDM)