Comprehensive AC Performance Analysis of Ceramic Capacitors for DC Link Usage

The paper explains the needs for using of an additional DC link capacitor closely to fast switching semiconductor and derives design rules for it. Results of the shown study on X7R, X6S, X7T and CeraLink capacitors help to choose correct capacitor for DC link usage, to be able to design switching cell properly. Cs and ESR of capacitors were measured and compared to typical datasheet values, and completed with large amplitude measurements (iac=1A) for different DC-voltages, frequencies and higher temperatures (RT/80 deg C /125 deg C). Design rules are proved empirically implying corrected capacitance values of used capacitors.