Clamping system for series connected IGBTs to avoid transient breakdown voltages

Authors

  • Masoomeh Boloorian Technical University of Denmark Elektrovej 325 2800 Lyngby
  • Tonny W. Rasmussen Technical University of Denmark Elektrovej 325 2800 Lyngby
  • Walid Z. El-Khatib Technical University of Denmark Elektrovej 325 2800 Lyngby

DOI:

https://doi.org/10.5324/nordis.v0i24.2295

Abstract

IGBTs (Insulated Gate Bipolar Transistor) can be used for power DC-DC converters at higher voltages. A series connection is needed due to the blocking
capability limit of 6500V. The voltage must be shared among the IGBTs both dynamic when switching and blocking mode. A non-synchronized switching creates transient voltage that might damage the IGBT. The non-synchronized switching comes from different delays in the gate drivers and deviation in the IGBT parameters. This paper investigates in theory and practice a solution
contains of clamp circuit, dynamic and static circuit. Turning on process of the stack of three IGBTs are in focus in a buck converter design. An operating
voltage closer to the IGBT limit is used in order to press the system. For the simulations (Pspice) and experimental tests, fast IGBTs (1200V /30A IXYH40N120C3) are used to show the good dynamic of the chosen solution. The Lab tests also show that because of the deviation in parameters preadjustment of the gate signals is needed. The experimental tests have been carried out in different clamp voltage to finally have clamp voltage close to
the blocking voltage of the IGBTs and maximum 2A as output current. Examples of wave forms for voltages are given and discussed.

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Published

2017-09-04