Phase Shift-Controlled Dual-Frequency Multi-Load Converter with Independent Power Control for Induction Cooking Applications

Abstract

Induction heating (IH) applications, assisted with converter topology and their control, have become very attractive in recent years. Independent power control for any induction cooking application with simple converter topology, multi-load handling capacity, and a control technique is still a research hot spot. This paper focuses on developing the dual-frequency converter for delivering power to two loads independently. The switching frequencies of the converter for loads 1 and 2 are selected as 20 and 80 kHz, respectively, and the inverter is operated by multiplexing two switching frequencies. The independent power control is performed using a phase shift control scheme and validated in real-time using a PIC16F877A microcontroller. The prototype of 1 kW is developed and load 1 is operated with 550 W and load 2 is operated with 270 W output power. The independent power control is verified for various values of the control angle (ϕ) and it is noticed that the efficiency is 91% at 0∘ and it is above 80% for other values of ϕ. The thermal model of the proposed system is studied using COMSOL multiphysics software and the experimental image is recorded using a FLIR thermal imager. It is noted that the temperature rise in the load is 78 ∘C and 38.5 ∘C for loads 1 and 2, respectively, at time t = 180 s.