IGBT high frequency operation

IGBT (insulated gate bipolar transistor) devices have been designed into low frequency (<20 kHz) power controls for many types of equipment. This equipment includes: high voltage applications such as 120 V to 440 V motor controls; AC power line conditioning; and automotive ignition systems. It can be quite disconcerting to have an IGBT power control design that generates radio frequency interference (RFI) at RF power levels to penetrate nearby electronic systems. These RF oscillations affect the reliability of the IGBT if they become self-sustaining. The cause of the RF oscillations is due to the IGBT design and to the IGBT driver circuit. IGBT simulation models and actual lab test results suggest that IGBT models may not accurately compute the IGBT's RF characteristics. Methods to minimize RF oscillations for IGBT power designs include careful PCB layout and gate driver design.