Aerospace & Defense Technology - October 2022 - 21

Cockpit avionics, which typically rely on 28-volt systems, may only require
power conditioning from a local electrical bus or battery.
The Royal Air Force's venerable Typhoon fighter aircraft will be replaced by
the Tempest, a 6th generation combat aircraft expected to enter service in the
mid-2030s. (Image: BAE Systems)
approach driving greater consideration of DC-DC power distribution
and conversion strategies in aircraft design.
Power electronics are designed with attention to diverse factors
such as magnetics, discrete components, expected performance,
and thermal efficiency, helping developers define and
address design problems earlier. This strategy also supports the
increasing need for design scalability - reducing costs and
accelerating timelines in an environment anticipating greater
power needs across a spectrum of flight-qualified applications.
These factors point to a more holistic approach raising in
importance as well, recognising the enabling characteristics of
DC-DC power conversion and distribution technologies.
Voltage conversion and power conditioning are required
when power is distributed as DC, however these factors vary
with specific power applications onboard the aircraft. One
design may deliver a chosen voltage and then convert it up or
down at the device; another may adjust a power level before
it is distributed to its intended application. In choosing a
path, designers must not only consider the aircraft and its role
in flight operations, but also factors such as lifecycle, required
reliability, scalability, system weight trade-off, and more.
Because of these complexities, as well as continued rapid evoAerospace
& Defense Technology, October 2022
lution of power demands for aerospace applications, a building
block strategy proves useful. Developers can accelerate
development with proven, modular designs that can be
sourced for both performance and scalability.
DC Power Distribution Designs
Individual areas of an aircraft may only require power conditioning
from a local electrical bus or battery. Cockpit avionics
provide an example, typically relying on 28-volt systems.
These systems, contained within a specific area of the aircraft,
provide an example of power requirements that may only
require power conditioning. Alternatively, designs may opt to
centrally convert and distribute 28 VDC to specific systems
and areas onboard. Because of the cable weight associated
with wide distribution of power, it is the smaller, simpler
architectures that are ideal candidates for this approach.
Redundancy and manageable degradation of performance can
be built-in. For military airframes, these values are critical to
improving safety and survivability.
As a design tactic, increased voltage offers a functional
trade-off against cable weight. This can be illustrated using a
primary, 540-volt distribution supported by a localized secmobilityengineeringtech.com
21
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Aerospace & Defense Technology - October 2022

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