Investigation of Passive LC Filter in the Induction Heating System with High Frquency Power Supply

An investigation of voltage harmonics and high-frequency conductive interference generated by an induction installation powered by a high-frequency transistor power supply VGT series was carried out. Previous studies have shown the presence of even and odd harmonics, which indicates the need for conducted interference filters. An analysis of various filters given in the literature has been carried out, which has shown that passive filters have some advantages and can be effectively used in this particular case. Based on the analysis of harmonics and critical frequencies in these power supplies, a passive LC filter was designed and installed, which made it possible to eliminate even harmonics and significantly reduce odd harmonics. Problems of already existing background RF interference in the industrial electrical network 220/380 V, to which the power supply was connected, are shown. In this regard, there is an ambiguity in estimating the efficiency of the LC filter for high-frequency voltage components. The results of measurements and calculations showed that if an induction heater with the transistor power supply is connected to the “ideal“ network, then the highfrequency interference would not exceed the standard values.