Influence of parasitic elements on radiated emissions of a boost converter

A highly detailed evaluation of the influence of parasitic elements, e.g. semiconductor inductances and heat sink capacitances, on radio frequency noise of a power electronic circuit is presented, using measurements in time domain. Fast switching semiconductors trigger oscillations during the switching process, that are critical under electromagnetic interference (EMI) considerations. Separate equivalent resonant circuits for the turn-on and turn-off process of a semiconductor in a boost converter topology are derived, representing the most critical oscillation circuits. The discrete semiconductor packages TO220, DPak, and TO247-4 are investigated and compared. The derived results are verified by measurements of the radiated far field in a semi anechoic chamber.