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

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
1
Pulsed Power System with
Examples of System Components
Intermediate
Energy Store
PFN
Coaxial Cable,
Stripline
Switch
Semiconductor Device,
Spark Gap
Load
Plasma Drill,
Treatment Cell
HV
PowerSupply
2
Comparison of solid-state
switching devices
Voltage
Rating
Current
Rating
Speed
Thyristor
High
High
Low
GTO
High
High
Low
MOSFET
Low
Low
High
MCT
High
Medium
Medium
MAGT
Medium
High
High
SIT
Medium
Medium
High
IGBT
Medium
Medium
High
Availability
Readily
available
Medium
Readily
available
Special order
only
Special order
only
Special order
only
Readily
available
Cost
Low
Medium
Low
High
High
High
Low
3
An X2 Non-Inverting Blumlein
Cable Generator
OUTPUT
CHARGING
HV ELEMENT
b
a
CABLE 1
c
d
CABLE 2
SWITCH
4
Problems associated with
stacking IGBTs
•
•
•
•
•
•
•
Signal synchronisation
Signal isolation (Magnetic or Optical )
Voltage sharing (Passive or Active snubbers)
Current sharing
Stack configuration
Diagnostic
Protection
5
Photograph of 55 IGBT stack with voltage and
current ratings of 2.5 kV and 250 A, respectively.
6
Voltage across the device and output pulse for
two 1.2 kV IGBTs
7
Photograph of 10 kV, 400 A stack of IGBT modules
consisting of 105 1.2 kV IGBTs.
8
Photograph of 10 kV, 400 A stack of IGBT modules,
optically triggered
Over-voltage
protection circuit
9
Photograph of 3 kV, 2 kA Marx
generator
10
Conclusion
• The IGBT was determined to be the preferred device for stacking
• IGBT’s 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.
11