Performance verification of a novel soft switching three-phase utility frequency AC to high frequency AC direct power converter with PFC function for industrial IH applications

This paper presents performance characteristics of a novel soft switching three-phase utility frequency AC (UFAC) to high frequency AC (HFAC) direct power converter with PFC function for industrial induction heating (IH) applications. The proposed "simple three-phase system" consists of a single-phase UFAC to HFAC direct converter unit in each phase, three-phase low pass filter and three-phase IH load. This power converter can regulate the output power under a condition of the constant frequency zero voltage soft switching (ZVS) commutation principle on the basis of unique asymmetrical PWM control scheme. In this paper, high frequency IH output and utility AC current characteristics of three-phase direct converter supposed 5kW class IH system are demonstrated and evaluated from computer aided simulation with PSEVI software. Furthermore, basic performance analysis of the single-phase converter unit is evaluated from an experimental point of view.