IEEE Electrification Magazine - June 2015 - 3

ship have not been realized. However,
the tangential advances in process
controls and development of smart
motor controllers have led to increasing automation of the ship's electrical
system and hull mechanical equipment, which is reducing the manning requirements for ship operation.
The most significant opportunity
enabled by power electronic conversion, however, is the integrated
power system (IPS), which provides
electric power to the entire ship (propulsion, ship service, and hull
mechanical equipment) in an integrated fashion.
An IPS enables shipboard electrical
loads, such as pumps and lighting, to
be powered from the same electrical
source as the propulsion system (i.e.,
the electric drive), eliminating the
need for separate power generation
capabilities for ship service distribution. The anticipated benefits of IPS
include fewer prime movers, improved
fuel savings, flexibility in locating
prime movers, and improved survivability. The implementation of IPS into
new ship designs has enabled the allelectric ship, with integrated electric
propulsion and electric weapons, and
has motivated the development of
what is, effectively, a dc microgrid in a
shipboard environment, with its attendant opportunities and challenges.
All of these shipboard electrification
developments in the naval shipbuilding industry have led to significant
changes to the American Bureau of
Shipping Naval Vessel Rules and have
spawned the development of new IEEE
standards with a futuristic view of fully
automated, highly survivable, medium-voltage dc (MVdc) IPS. It is not a
stretch to state that the technologies
and hardware being developed for
shipboard electrification are now leading the way to fully integrated
microgrids, particularly in the areas of
energy storage management and distribution system protection.

An article in the March 2015 issue of
connection of power electronics to a
IEEE Electrification Magazine, "Advanced
grid, is much lower in the shipboard
Control Solutions for Operating Isolatelectrical system than in most other
ed Power Systems," by H. Vasconcelos,
applications. These effects must be
C. Moreira, A. Madureira, J.P. Lopes, and
mitigated through additional filters
V. Miranda, points out the challenges of
and enclosures, which inevitably lead
operating isolated microgrids due to
to increased size, weight, and heat in
small system inertia. Those challenges
an environment where those attriare not only present in shipboard
butes often come at a premium.
power systems but are compounded
Moreover, with the increased connecby the small physical size limitations
tion of power electronics to this soft
relative to the installed power of the
electrical system comes new chalall-electric ship. Under normal condilenges and paradigms for electrical
tions, the ship is actually an isolated
system protection.
microgrid with its own distributed
In this special issue, we have includenergy resources. These resources
ed a total of seven articles (five features
must be managed in an integrated
and two columns) covering a diverse set
fashion to ensure that the ship accomof topics on naval power systems, voltplishes its mission or
age regulation, the imreaches its destination
pact of energy storage,
The tangential
under myriad scenaridc system protection,
advances in process
os that can occur.
and standards. We
The electrical disopen this issue with
controls and
tribution voltage is efthe article "Naval Powdevelopment of smart
fectively "soft" so that
er Systems," which
motor controllers have
transients associated
provides a compreled to increasing
with bringing on
hensive overview of
large loads, such as
the challenges facing
automation of the
pumps or propulsion
naval shipboard power
ship electrical system
motors, are closely
systems, including the
and hull mechanical
coupled to the generultimate goal of the
equipment.
ation system perforMVdc shipboard IPS.
mance and stability.
The articles that folAt the same time, the
low address some key
density of electrical equipment on a
aspects in achieving that goal. While
ship and the proximity to ground pothese articles may seem primarily fotential at all times is more severe in a
cused on naval systems, they apply to
ship than in most other applications.
the improvement of efficiency and reliAs a result, the vast majority of the
ability of all shipboard and marine
electrical distribution, in most cases,
power systems. The naval systems lie
is ungrounded. Often an electrical
at the forefront because of more strinfeed has a ground fault, but the elecgent requirements in space and pertrical system must continue to operformance. We hope that you enjoy the
ate without degradation. While the
overview of the interesting and chalshipboard soft grid and the need to
lenging engineering problems that
distribute both generational and enerthey describe. If you would like to subgy storage sources demand an inmit an article or if you want a specific
creased application of power electopic to be addressed in future issues,
tronics, the tolerance of poor power
please contact us at electrification@
quality and electromagnetic interferieee.org.
ence, the by-products of large-scale

IEEE Electrific ation Magazine / J UNE 2 0 1 5

Table of Contents for the Digital Edition of IEEE Electrification Magazine - June 2015