Fast high-voltage, high-current switching using stacked IGBTs

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Fast high-voltage, high-current switching using
stacked IGBTs

• By Zarir Ghasemi
• Supervisor Prof. S. J. Macgregor
• Institute for Energy and Environment
• University of Strathclyde
• Glasgow

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Pulsed Power System with Examples of System
Components
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Comparison of solid-state switching devices
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An X2 Non-Inverting Blumlein Cable Generator
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Problems associated with stacking IGBTs

• Signal synchronisation
• Signal isolation (Magnetic or Optical )
• Voltage sharing (Passive or Active snubbers)
• Current sharing
• Stack configuration
• Diagnostic
• Protection

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Photograph of 5?5 IGBT stack with voltage and
current ratings of 2.5 kV and 250 A,
respectively.
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Voltage across the device and output pulse for
two 1.2 kV IGBTs
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Photograph of 10 kV, 400 A stack of IGBT modules
consisting of 10?5 1.2 kV IGBTs.
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Photograph of 10 kV, 400 A stack of IGBT modules,
optically triggered
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Photograph of 3 kV, 2 kA Marx generator
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Conclusion

• The IGBT was determined to be the preferred
  device for stacking
• IGBTs can handle a peak current of five times
  their normal rating during short-pulse
  conducting, if they are driven by fast gate
  pulses.
• The dual degradation of the collector-emitter
  voltage exists in some of available IGBT devices.
• A prototype stack at voltage and current ratings
  of 10 kV and 400 A, with a voltage fall-time of
  about 45 ns was successfully tested.
• An optically-coupled stack of IGBTs with voltage
  and current ratings of 10 kV and 400 A was built
  and operated in a generator, used for Pulsed
  Electric Field (PEF) inactivation of
  microorganisms.
• A modular Marx generator, having an output
  voltage rating of 3 kV and a peak current rating
  of 2 kA, was designed and evaluated.