IEEE Electrification Magazine - December 2014 - 2

AbOUT THIS ISSUe

More Electric
Aircraft-A Reality
By Bulent Sarlioglu

VER THE LAST FEW DECADES, THERE HAS BEEN TREMENdous progress in the efforts to move toward More Electric
Aircraft (MEA). Many subsystems that previously ran
using hydraulic, mechanical, and pneumatic systems have been
fully or partially replaced with electrical systems. One of the drastic
changes in some commercial transport aircraft has been the elimination of the integrated drive generator (IDG). The IDG had been
used to change the variable speed of the jet engine to constant
speed via mechanical means. This system provided constant frequency and constant voltage to the aircraft bus. In some of the most
recent commercial transport aircraft, including the Boeing 787 and
Airbus A380, the main engine generator is directly coupled to the jet
engine via a gearbox. Hence, the frequency of the electrical power in
the aircraft's power busses is proportional to the engine speed. The
frequency variation range at the engine generator output is set to a
desired value depending on the variation of the engine speed, e.g.,
between 350 and 800 Hz, depending on the engine design. The ac
voltage produced by the generator is regulated at a fixed value, such
as 115 or 230 Vac, using a generator-control unit. This paves the way
for a constant-voltage and variable-frequency power bus. Hence,
many current loads that have run at a constant 400 Hz in the traditional aircraft with IDGs would
now require additional provisions
One of the drastic
to convert power from one form to
changes in some
another, i.e., ac-dc and dc-ac.
commercial transport
Another example of the
expanding use of electrical sysaircraft has been the
tems is the elimination of the use
elimination of the
of bleed air for environmental conintegrated drive
trol systems. Environmental congenerator.
trol systems are used to achieve
passenger comfort by regulating
the cabin temperature and pressure. Bleed air had been obtained from one of the compressor stages
of the main engine; however, in the Boeing 787, instead of tapping

O

Digital Object Identifier 10.1109/MELE.2014.2375471
Date of publication: 9 February 2015

2

I E E E E l e c t r i f i cati o n M agaz ine / december 2014

EDITORIAL BOARD
Saifur Rahman
Editor-in-Chief
Virginia Tech
Virginia, USA
srahman@vt.edu
Iqbal Husain
Editor, Electric Vehicles
North Carolina State
University
North Carolina, USA
ihusain2@ncsu.edu
Eduard Muljadi
Coeditor, Electric Vehicles
NREL: Wind Research
Colorado, USA
eduard.muljadi@nrel.gov
Herb Ginn
Editor, Electric Ships
Universitiy of
South Carolina
South Carolina, USA
ginnhl@cec.sc.edu
Robert Cuzner
Coeditor, Electric Ships
DRS Power and Control
Technologies
Wisconsin, USA
RobertMCuzner@drs.
com
Eduardo Pilo de la
Fuente
Editor, Electric Trains
EPRail Research
and Consulting
Spain
eduardo.pilo@eprail.com
Jose Conrado Martinez
Coeditor, Electric Trains
Directcion de Estrategia
y Desarrollo
Spain
jcmartinez@adif.es
Bulent Sarlioglu
Editor, Electric Planes
University of
Wisconsin-Madison
Madison, USA
bulent@engr.wisc.edu

Mohammad
Shahidehpour
Editor, Off-Grid
Illinois Institute
of Technology
Chicago, USA
ms@iit.edu
Steve Pullins
Coeditor, Off-Grid
Horizon Energy Group
Tennessee, USA
spullins@horizonenergy
group.com
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Digital Object Identifier 10.1109/MELE.2014.2378371
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Table of Contents for the Digital Edition of IEEE Electrification Magazine - December 2014
