A comparison of asymmetrical control strategies for domestic induction cooking applications with low-quality factor loads

Abstract

This paper presents a comparison of two control strategies between the fixed-frequency method and the variablefrequency method for output power control of a full-bridge resonant inverter in domestic induction cooking to address an issue of the distorted load current due to low-quality-factor load. The control strategies are based on the asymmetrical control using positive half-cycle control while operating under zerovoltage-switching (ZVS) and non-zero-voltage-switching (NON-ZVS) conditions. Load characteristics of different types of cooking materials are analyzed. The variable-frequency method can improve the inverter efficiency over all ranges of power compared with the fixed-frequency method due to reduction of the switching losses in the devices of inverter. The functionality and benefits of the proposed control strategies are verified through the experimental results.