Pulse density modulated zero current soft-switching series resonant high frequency inverter for consumer induction-heated roller

This paper presents the voltage source type half bridge lossless auxiliary inductor assisted series resonant high frequency inverter for induction heated fixing roller in copy machines. This high-frequency inverter treated here can completely achieve zero current soft switching (ZCS) commutation for wide power regulation range under its constant frequency pulse density modulation (PDM) scheme. Its transient and steady state operating principle is originally presented for a constant frequency PDM control strategy under a ZCS operation commutation, together with its output effective power regulation characteristics-based on the PDM. The experimental operating performances of this ZCS-PDM high frequency inverter using IGBTs are illustrated as compared with computer simulation ones. Its power losses and actual efficiency are evaluated and discussed on the basis of simulation and experimental results