Switching Behavior of IGBTs in Phase Shift Full Bridge ZVT DC/DC Converter

摘要

New “high speed” generations of IGBTs (e.g. Infineon’s high speed ‘IGBT_H3’) have alreadybeen recognized as a cost-effective alternative to superjunction MOSFETs in zero voltagetransition (ZVT) phase shift full bridge (PS FB) high voltage (HV) to low voltage (LV) DC/DCconverter for hybrid and electric vehicles. In converter designs with superjunction MOSFETs,external resonant inductors and capacitive snubbers are recommended measures toincrease the efficiency. In this paper, the same efficiency improvement methods areanalyzed in a converter design with high speed ‘IGBT_H3’. The effect of such additionalcomponents on the switching losses of IGBTs and overall converter efficiency is discussedbased on experimental results from a prototype converter. It is shown that such measuresare affecting IGBT’s switching dynamics in a way that switching losses are not reduced astheoretically expected. The consequence is that the best performance of the IGBT_H3 isachieved when minimum amount of external components is applied, which is a great benefitin terms of converter’s cost and complexity.