Improved power quality buck-boost converter fed LLC resonant converter for induction heater

This paper deals with power factor corrected (PFC) buck-boost converter fed half bridge LLC resonant induction heater (IH) for domestic induction applications. The front end buck-boost PFC converter regulates the DC link voltage to a lower value than a conventional boost converter while maintaining improved power quality at universal input mains. PFC converter switch current stress is controlled by operating buck boost converter in CICM (Continuous Inductor Current Mode) using classical internal current loop and outer voltage loop approach. The LLC induction DC-AC inverter fed from PFC buck-boost converter converts DC to high frequency (25 kHz) voltage suitable for domestic heating. A 2 kW buck-boost PFC converter with LLC-IH load is designed and simulated using MATLAB.