Design and Analysis of EMI and RFI Suppressor for High Frequency Full Bridge Resonant Inverter Fitted Induction Heater

This paper presents the design and analysis of EMI and RFI suppressor using PSIM for full-bridge resonant inverter based induction heating equipment. With the growing use of high frequency inverters in induction heating equipment, the problem of injected harmonics becomes critical. These harmonics require the connection of low pass filters between the inverter and the power supply network. The design is according to the harmonics standards that determine the level of current harmonics injected into the power supply network. To reduce the radiated and conducted interference from electronic equipment to moderate level United States and international standards for EMI-RFI have been established. FCC Docket 20780 is the document which serves as the guide in the United States. Internationally acknowledged document is the West Germany Verband Deutscher Elecktronotechniker (VDE) safety standards. So it is clear that both the FCC and VDE standards exclude subassemblies from agreement to the rules; rather, the final equipment i.e. the switching power supply must abide by the EMI-RFI specification. The input filter of the switching power supply is matched with the power supply when connected with passive loads. The characteristics and suppression capabilities may drastically change when used to power active high frequency electronic circuits. In this paper an attempt is made by the authors to introduce the reader with the conducted RFI problem. Some methods are also suggested by the authors to reduce the interference problem both for the application in a power supply system of high frequency resonant full bridge inverter fitted induction heating equipment. Also a simulated analytical comparison has been made between two induction heating equipment’s including and excluding the EMI and RFI suppressor.