IEEE Electrification Magazine - December 2017 - 63

Moving toward
the MEA involves
increasing the
electrical power
generation and
distribution
capability of the
aircraft to supply
most of the loads.

emissions from the transportation
sector. On the other hand, indepen-
dent of climate policy actions, the
projections are that fossil fuel
reserves will become exhausted
within the next 50 years. If a more
sustainable future is to be achiev-
ed, the issues of greenhouse emis-
sions and energy security must be
addressed. One long-term solution
may well lie in both the adoption of
current best technologies and in the
development of more advanced tech-
nologies, in all sectors of transporta-
tion (International Energy Agency
2009). A shift toward more efficient
modes of transport, including the
more electric aircraft (MEA), are not merely needed, but
are required.

MEA
In conventional aircraft, engines generate power from fuel.
The bulk of the power is used for propulsion; the remain-
der is transformed to hydraulic, pneumatic, mechanical,
and electrical power to supply different loads in the aircraft
(Wheeler and Bozhko 2014, Boglietti et al. 2009). Pneumatic
power is used for the environmental control system (ECS)
and wing anti-icing. Hydraulic energy is used to power
flight controls and landing gears. Mechanical systems are
driven by mechanical power through gearboxes. Electrical

power is used for lighting, avionics,
and commercial loads. Moving toward
the MEA involves increasing the elec-
trical power generation and distribu-
tion capability of the aircraft to supply
most of the loads. This shift toward
electricity rests on the development
of power electronics (PE). It is this
enabling technology that can contrib-
ute to high-efficiency improvements
in the aircraft, based on distinctive
features such as high power capability
and controllability.
PE technology is paving the way
toward the more electric engine and
more electric loads in the aircraft. The
engines of the MEA will be started
with an inbuilt starter/generator instead of high-pressure
air (Moir and Seabridge 2011). The vanes to control airflow
to the engine central core will be driven by PE converters.
PE will enable fuel pumps to run at their optimum speed
in accordance with prevailing operating conditions (Moir
and Seabridge 2011). This will significantly reduce wasted
pumping energy. A large part of the aircraft loads, which
run on pneumatic or hydraulic energy, will be controlled
by PE converters, leading to further increase in efficiency
(Moir and Seabridge 2011). These include ECS and wing
anti-icing. Pressurization will be performed by electrically
powered compressors. Most hydraulic and pneumatic
actuators will be replaced by electromechanical actuators

Fan
Controllers

Gen

Power
Distribution and
Conversion

Flight Control
Actuators

Gen

Power
Electronics
Cooling
Systems

Avionics-IFE
Gen

Power
Distribution and
Conversion

Electric
Brakes
WIPS
Cabin Air
Compressor
Electric-Driven
Hydraulic
Pumps

Figure 1. The Boeing 787 has a total of 1 MW of PE loads (Karimi 2007). GEN: generator; IFE: inflight entertainment; WIPS: wing ice-protection
system.

IEEE Elec trific ation Magazine / D EC EM BE R 2 0 1 7

Table of Contents for the Digital Edition of IEEE Electrification Magazine - December 2017