ANSYS Advantage • Volume II, Issue 4, 2008
ANSOFT: ELECTROMECHANICAL
www.ansys.com
27
Electric Motors
Advanced by
“Ultra” Power Storage
Electromechanical simulation tools aid in the design flow
of hybrid–electric systems.
By John M. Miller, Vice President Advanced Transportation, Maxwell Technologies, Inc., California, U.S.A.
Marius Rosu, Group Leader Simplorer Modeling, Ansoft LLC
In the energy storage industry,
electric double-layer capacitors are
becoming widely accepted both in
stand-alone applications and in com-
bination with batteries. Also known as
ultracapacitors, these devices com-
bine a relatively vast electrode surface
area with a molecular-scale charge
separation distance, providing capaci-
tances that are several orders of
magnitude higher than more common
electrostatic or electrolytic capacitors.
As the technical and economic
benefits of
these power-dense
components become more widely
understood, there is increased interest
in the active combination of ultra-
capacitors as electrical storage
elements with energy-optimized bat-
teries, such as nickel metal-hydride
and lithium-ion, as the means to offer
reliable energy storage over wide
temperature and operational limits.
Computer simulation of ultra-
capacitors and advanced batteries
is becoming more widespread as
the engineering community becomes
better attuned to global climate
change and the subsequent demand
for more efficient energy storage
systems. Examples of ultracapacitors
working in combination with advanced
batteries continue to proliferate, primarily
in the electric and hybrid–electric
commercial transportation segments
such as transit buses and trains. In
such systems, brushless DC (BLDC)
motors and their component power
electronics play a significant role in
increasing the overall system efficiency.
These motors supplement the output of
the internal combustion engine when
extra power is needed. They are also
used to start the engine, as opposed to
the conventional starter and solenoid
method.
When designing a variabl