A simple multi‐frequency multiload independent power control using pulse density modulation scheme for cooking applications

Abstract

Induction heating applications aided by power electronic control have become very attractive in the recent past. For cooking applications, power electronics circuits need to feed power to multi loads with a suitable control technique. The induction heating system requires a superlative converter topology and independent control to deliver power to multi loads. The main idea of this research work is to develop a dual-frequency half-bridge series resonant high-frequency inverter feeding power for multi loads independently. A pulse density modulation (PDM) control technique is used to control the output power independently. The inverter simultaneously powers both loads with constant switching frequency. The proposed system is simulated in MATLAB/Simulink and thermal analysis is carried out in COMSOL multi-physics software. A 1 kW prototype experimental set up is developed to feed power to dual load with the switching frequencies of 20 and 80 kHz for load 1 and load 2, respectively. The experimental results are provided to validate the system performance for various duty cycles of the PDM signal. The simulation and experimental results are in good agreement. The efficient power control is accomplished by varying the density of the switching pulses.