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Introducing the hybrid unipolar bipolar field effect transistor : the HUBFET
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Donnellan, Benedict T. (2013) Introducing the hybrid unipolar bipolar field effect transistor : the HUBFET. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b2689330~S1
Abstract
Modern commercial aircraft are becoming increasingly dependent on electrical
power. More and more of the systems traditionally powered by hydraulics or
pneumatics are being migrated to run on electricity. One consequence of the
move towards electrical power is the increase in the storage capacity of the bat-
teries used to supplement the power generation. The increase in battery size
increases the maximum stress that a short circuit failure can put on the power
distribution system. Although such failures are extremely rare, the fail safe
switches in the distribution system must be capable of handling extremely high
energy short circuits and turning off the power to protect the electrical systems
from damage. Traditionally aircraft have used electromechanical relays in this
role. However, they are large, heavy and slow to switch. As the potential power
level is increased, the slow switching becomes more of a problem. The solution is
a semiconductor switch. An IGBT can handle the high short circuit currents and
switches fast enough to prevent short circuits damaging key systems. However,
the inherent voltage drop in the forward current path significantly reduces its
efficiency during nominal operation. A power MOSFET would be considerably
more efficient than an IGBT during nominal operation. However, during high
current surges, the ohmic behaviour of the switch leads to extremely high power
loss and thermal failure. In this thesis a solution to this problem is presented.
A new class of semiconductor device is proposed that has the highly efficient
low current performance of the power MOSFET and the high current handling
capability of the IGBT. The device has been named the Hybrid Unipolar Bipolar
Field Effect Transistor or HUBFET. The HUBFET operates in unipolar mode,
like a MOSFET, at low currents and in bipolar mode, like an IGBT, at high
currents. The structure of the HUBFET is a merging of the MOSFET and
IGBT. It is a vertical device with a traditional MOS gate structure, however
the backside consists of alternating regions of both N-type and P-type doping.
Through simulation the key on-state characteristics of the HUBFET have been
shown. Fabricated test modules have been tested to validate the simulations and
to show how the HUBFET can dynamically transistion from unipolar to bipolar
mode during a short circuit event. Following the proof of concept the pattern of
implants on the backside of the device that give the HUBFET its characteristic
were investigated and potential improvements to the design were identified.
Item Type: | Thesis (PhD) | ||||
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Subjects: | T Technology > TK Electrical engineering. Electronics Nuclear engineering T Technology > TL Motor vehicles. Aeronautics. Astronautics |
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Library of Congress Subject Headings (LCSH): | Metal oxide semiconductor field-effect transistors, Field-effect transistors, Airplanes -- Electric equipment, Airplanes -- Electronic equipment, Semiconductor switches | ||||
Official Date: | February 2013 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | School of Engineering | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Mawby, P. A. (Philip A.); Jennings, M. R. | ||||
Extent: | xv, 236 leaves : illustrations. | ||||
Language: | eng |
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