Home' Asia Pacific Defence Reporter : APDR October 2015 Contents Unlike lead acid cells, which can develop a ‘memory’,
Li-Ion cells don’t. Li -Ions are maintenance free in normal
operation, do not consume distilled water, require no
cooling water systems and do not release gas therefore
eliminating the need for battery ventilation systems,
hydrogen monitoring, hydrogen elimination systems
and battery compartment flushing systems. This saves
space and reduces hotel loads. Ten-year life cycles can
be expected from these batteries.
The French, Germans and Japanese have all been
working on submarine Li-Ions for some time now.
The European’s have both got to the point of having
integrated test sites, although it appears the Japanese
will beat the Europeans in having Li Ion’s at sea. It
remains to be seen, however, what the capability aim
point of each contender’s solution is.
Inclusion of Li-Ions on Australia’s future submarine is
an almost given and will attach low project risk.
DCNS, TKMS and the Japanese will all use permanent
magnet (PM) motors in their SEA 1000 offerings. PM
motors differ from standard DC motors by replacing
rotor coils, which require electrical excitation (and
therefore energy), with rare-earth permanent magnets.
They deliver high torque at low RPM that allows for
the use of large diameter propellers turning at low
RPM. This facilitates high propulsive efficiency and a
reduction in the potential for propeller cavitation noise.
TKMS will offer a 6+ MW Siemens PermasynTM
motor for its concept design.
The Permasyn is the result of the totality of Siemen’s
experience in a wide range of motor applications. It has
an ingenious bell shaped rotor that permits the stator
switching electronics to be housed inside the bell,
thereby allowing the motor to occupy a much smaller
space than its French and Japanese equivalents.
The 6+ MW Permasyn motor will have up to 18
inverter modules with half of them powered from
different sources. These inverters control the stator
current phase, magnitude and curve shape which
permits efficient and seamless operation over the
motor’s full speed range, including astern. If any of
the invertor modules fail the motor will keep running; it
will even run (albeit poorly) on one module. The motor
design has large thermal reserves that only requires
ventilation/cooling at high speed, making the motor
quieter and more efficient in the crucial low speed
range likely within an operational area.
The housings of the motor are available in
A comparison of a Permasyn and French Magtronic
motor using available public domain figures
is instructive as to the Permasyn’s efficiency. A
published UDT paper reveals the efficiency of the 3.3
MW Scorpene motor to be 2% less than the similar
generation 4 MW Type 214 Permasyn at high speed
and 7% less at all-important low speeds. This is
significant in the context of an entire patrol.
The Permasyn has been under development since
the early eighties with ten 2 MW variants and ten 4
MW variants at sea.
Design work has already started on the SEA 1000
Permasyn. From a risk perspective, the project involves
complexity and uncertainty, but is being conducted by a
very experienced team. With respect to that experience
the company has built a 6 MW submarine DC motor
(i.e. non PM) for the Argentinian TR1700 program and
recently supplied 11 MW PM motors to Australia for
the RAN’s LHDs. The company has also produced 100
MW motors for commercial application. Additionally,
the Permasyn team in Berlin has already up-scaled their
motor twice, once from a one MW surface ship motor
to a two MW Type 212 motor and a second time from
a two MW motor to a four MW Type 214 motor. When
considering these factors, the project risk must be
assessed as low edging towards medium.
The French have designed and developed a 7 MW
PM motor for the Brazilian nuclear submarine program;
it was delivered this year to form part of the program’s
propulsion land based test site. Little is known about it,
but it is unlikely to possess some of the beneficial and
patented features of the Permasyn described above.
Noting it exists but has not yet been to sea, it would
justify a project risk characterisation of low.
The intentions of the Japanese with respect to SEA
1000 are unknown. They have a 5.9 MW Fuji Electric
PM Motor on the Soryu class, and whilst it comes
under the power rating of the DCNS and TKMS
solutions, its inclusion in their SEA 1000 solution
would ensure minimal project risk.
AN IMPRESSIVE SYSTEM
Unfortunately, whilst DCNS and the Japanese were
approached with a view to having this article detail all
three contenders’ wares, both declined to participate
in an objective comparison. As such this article
predominantly showcases the likely TKMS SEA 1000
concept design submarine propulsiwon chain.
The TKMS submarine propulsion chain comprises
tightly coupled and well matched components totally
integrated into an Integrated Platform Management
System for primary control, with local control for
backup. The system has been developed and enhanced
across four decades and is likely reliable, compact,
efficient and have low signatures. Some changes will
be required to meet the needs of a larger TKMS SEA
1000 submarine, but the risks associated with the
changes have been shown to be relatively low in nature
and well worth accepting. ¢
DISCLOSURE: Rex Patrick has visited DCNS, MHI/KHI, Navantia and SAAB
Kockums submarine yards in the past 18 months. This month he travelled to MTU,
Siemens and TKMS in Germany as a guest of the German-Australian Chamber of
Industry and Commerce.
Figure 2 – Siemens PermasynTM Motor
44 Asia Pacific Defence Reporter OCT 2015
17/09/2015 5:20 pm
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