Challenges in Using the Latest Generation of IGBTs in Traction Converters

• Published in: EPE Journal Vol. 15; no. 4; pp. 13 - 18
• Main Authors: Bakran, Mark M., Eckel, Hans-Günter, Helsper, Martin, Nagel, Andreas
• Format: Journal Article
• Language: English
• Published: Routledge 01.12.2005
• Subjects: Device applications; IGBT; Traction
• ISSN: 0939-8368; 2376-9319
• DOI: 10.1080/09398368.2005.11463599

The voltage class 6.5kV was the last step to now cover completely the whole range of voltages for traction starting with 1.7kV and 3.3kV. This lead to the general introduction of the IGBT across the whole power range of traction. In first IGBT generations the Non Punch Through design dominated here. The latest generation of IGBTs feature characteristics like field-stop design or trench design. Thus high cosmic ray withstand capability can be combined with low VCesat. For the high-power high-voltage application as used in traction, the introduction of the field stop leads to a significant change in the switching behavior compared to the conventional NPT-design. It will be shown how the IGBT and diode turn-off characteristics change and how sensitive it is to parasitic circuit characteristics. Especially in high-power circuits with relatively large stray inductances, this is a device and application challenge. Further more it will be shown that the IGBT overvoltage during turn-off transients can be controlled only by using a highly dynamic gate driver. Since no active control ofthe diode turn-offis possible, the peak-voltage must be limited by appropriate circuit and device design. For new generations of IGBT and diode, this behavior should be considered carefully by the semiconductor development.