US010141854B1
(12) United States Patent
( 10) Patent No.: US 10 , 141,854 B1
(45) Date of Patent:
Nov . 27, 2018
Butler et al.
(54 ) ISOLATED POWER SUPPLY SYSTEM AND
References Cited
U . S . PATENT DOCUMENTS
(56 )
METHOD FOR AN UNDERSEA
COMMUNICATION CABLE
6 ,611,443 B2 8/2003 Gaudreau
2004 /0130215 A1* 7 /2004 Muramatsu ......... B60L 11/ 1811
( 71) Applicant: Diversified Technologies, Inc.,
Bedford , MA (US)
307/69
(72) Inventors : Neal R . Butler , Acton , MA (US ); Noah
H . Silverman , Cambridge, MA (US );
FOREIGN PATENT DOCUMENTS
Kevin Vaughan , Bedford, MA (US)
(73 ) Assignee: Diversified Technologies, Inc .,
* cited by examiner
Bedford , MA (US )
Subject to any disclaimer, the term of this
( * ) Notice: patent
is extended or adjusted under 35
U . S .C . 154 (b ) by 0 days .
(21) Appl. No.: 15 /689,521
( 22) Filed :
Primary Examiner — Jue Zhang
(74) Attorney, Agent, or Firm — Iandiorio Teska &
Coleman , LLP
(57)
ABSTRACT
An isolated power supply system for an undersea commu
Aug. 29 , 2017
(51) Int . CI.
HO2M 3 /335
( 2006 .01)
HO2M 1 /088
H04B 3 /54
( 2006 .01)
HO2M 1/32
( 2007.01)
( 2006 . 01)
2002153061 A * 5 /2002
JP
nication cable includes one or more power converters each
including input circuitry responsive to an input current from
a communication cable power conductor and in series with
the communication cable power conductor of the undersea
communication cable . One or more outputs are electrically
( 2006 .01 )
HO2M 1 /00
(52) U . S . CI.
CPC ....... HO2M 3 /33569 (2013 .01) ; HO2M 1 /088
(2013 .01) ; HO2M 1 /32 ( 2013 .01) ; H04B 3/54
isolated from the communication cable power conductor. A
controller is coupled to each of the one or more power
converters . The controller is configured to control the opera
tion of the one ormore power converters to provide the one
( 2013.01 ); HO2M 2001 /008 (2013 .01)
or more outputs coupled to an external load located on a
(58 ) Field of Classification Search
CPC .... HO2M 3 / 33569; HO2M 1 /088 ; HO2M 1 / 32 ;
HO2M 2001/008 ; H04B 3 /54
branch off of the undersea communication cable .
See application file for complete search history .
42 Claims, 9 Drawing Sheets
Undersea Communication Cable
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Sheet 9 of 9
US 10,141,854 B1
Providing one more power converters each including
input circuitry responsive to input current from an
undersea communication cable power conductor.
500
Providing one or more outputs electrically isolated
from the communication power conductor .
502
Controlling the operation of the one or more power
converters to output the one or more outputs coupled
to an external load located off a branch of the undersea
communication cable .
504
FIG . 10
US 10 , 141,854 B1
ISOLATED POWER SUPPLY SYSTEM AND
programmable output current, and a desired regulated DC
METHOD FOR AN UNDERSEA
COMMUNICATION CABLE
converters may include a plurality of sections configured to
FIELD OF THE INVENTION
power conductor between the sections . The controller may
The subject invention relates to an isolated power supply
system and method for an undersea communication cable .
BACKGROUND OF THE INVENTION
Intercontinental undersea communication cables may be
used to transmit high speed digital signals over low loss fiber
optics. Repeaters are needed at various intervals to amplify
current. The input circuitry of each of the one or more power
divide the input voltage from the communication cable
be coupled to the input circuitry of each of the one or more
power converters by magnetic isolation . The controller may
be configured to control the operation of the input circuitry
of each of the one or more power converters by pulse width
10 modulation . The one or more outputs may be electrically
isolated from the communication cable power conductor by
an isolation transformer. The input circuitry for each of the
one or more converters may include a modulated converter
followed by an inverter. The inverter may be configured to
and restore attenuated light signals . The repeaters are elec - 15 drive a transformer primary circuit including an isolation
tronic devices which require power. The repeaters are typi-
transformer, the transformer core , and a capacitor to allow
used to excite laser amplifiers embedded in the individual
may include a square wave inverter. The transformer core
cally a plurality of light emitting diodes ( LEDs ) which are
optical fibers . More complex repeaters , which receive the
switches of the inverter to open at low currents . The inverter
may be gapped to allow switches of the inverter to close at
light pulses, convert the light pulses to electrical signals and 20 zero voltage . The input circuitry of each of the one or more
retransmit optical pulses , may also be needed due to the power converters may include a bypass capacitor. The
accumulated dispersion of the very long undersea commu
modulator converter may include one or more controllable
nication cables.
switches and the inverter includes one or more controllable
To deliver power to the repeaters , high voltage , low
switches . The controller may be coupled to the one or more
current DC power sources e . g ., # 15 kV , 1 A , are placed at 25 controllable switches of the inverter, an arbitrary and
each end of the undersea communication cable . This power
dynamically changing external load impedance located on
is carried to all the repeaters by a single communication the branch of the undersea communication cable , the con
power conductor. The repeaters are connected in series such troller configured to measure the input current communica
tion cable power conductor, a regulated DC voltage output
to sea ground varies significantly along the cable , from a 30 by the modulated converter, a desired regulated DC output
very high positive voltage at the positive end, falling at each
voltage , a desired regulated DC current, and an external load
repeater, turning negative, and falling to a maximum nega - impedance and configured to determine and adjust the duty
that source current flows through the repeaters . The voltage
tive voltage at the negative end. The repeaters are electricycle of switching of the controllable switches of the modu
cally isolated from sea ground and are powered by current lated converter and the inverter such that the desired regu
flowing from one end of the cable to the other without regard 35 lated DC output voltage and /or the desired regulated DC
current is provided to the external load impedance . The
to the voltage to sea ground .
There is often a need to create a branch from the undersea
switching of the controllable switches by the controller may
branched and the relative voltage to sea water at any
bi- polar transistors (IGBTs), field effect transistor controlled
communication cable so communication between more than
include pulse width modulation . The controllable switches
two points may obtained without requiring completely sepa - of the modulated converter and the inverter may include one
rate cables . Powering the repeaters in a branch can be 40 or more of: field effect transistors , silicon carbide metal
problematic since the main power conductor cannot be oxide , field effect transistors (MOSFETs ), insulated gate
particular point is unknown variable or not at all defined . In Thyristors (MCTs), gate runoff Thyristors (GTO ), and power
addition , it may be desired to supply power to nearby Darlingtons . The system may include a voltage regulator
external load which may have an arbitrary and dynamically 45 coupled to the one or more power converters and the
changing resistance or power, such as undersea devices ,
equipment, and the like, not related to the typical main
controller configured to provide power to the one or more
power converters and the controller. The one or more power
converters may include a plurality of power converters . The
function of the undersea communication cable.
branching unit may be housed in a pressure vessel. The input
SUMMARY OF INVENTION
50 circuitry and each of the one or more power converters may
include an isolated variable DC -DC transformer circuit. The
In one aspect, an isolated power supply system for an controller may be configured to control the operation of the
undersea communication cable is featured . The system
variable DC -DC transformer circuit to provide current lim
includes one or more power converters each including input iting. The controller may be configured to control the
circuitry responsive to an input current from a communica - 55 operation of the variable DC -DC transformer circuit to
tion cable power conductor and in series with the commu- provide the output current. The controller may be configured
nication cable power conductor of the undersea communi
to control the operation of the variable DC -DC transformer
cation cable . One or more outputs are electrically isolated
circuit to provide voltage limiting . The controller may be
from the communication cable power conductor. A control-
configured to control the operation of the variable DC -DC
ler is coupled to each of the one or more power converters . 60 transformer circuit to provide the output voltage . The iso
The controller is configured to control the operation of the
lated DC -DC transformer circuit may include a program
one or more power converters to provide the one or more
mable voltage regulator . The controller may be configured to
outputs coupled to an external load located on a branch off control the operation of the isolated DC -DC transformer
circuit to provide power to the branch off the undersea
of the undersea communication cable .
In one embodiment, the one or more outputs may include 65 communication cable . The controller may be configured to
one or more of: an output voltage , a programmable output control the operation of the isolated DC -DC transformer
voltage, a regulated DC output voltage, an output current, a
circuit to provide power to a load off the undersea commu
US 10 ,141, 854 B1
nication cable . The system may include a fault protection
FIG . 1 is a schematic block diagram showing one example
circuit coupled to the communication cable power conductor
of a conventional system to deliver power to repeaters
and the isolated DC -DC transformer circuit configured to
located on an intercontinental undersea communication
bypass fault current around the input circuitry of one or more cable ;
power converters . The system may include an output voltage 5 FIG . 2 is a schematic block diagram showing in further
clamp coupled to the isolated DC -DC transformer circuit detail one example of the undersea communication cable
and the communication cable power conductor configured to
in FIG . 1 ;
limit the output voltage to a maximum desired output shown
FIG . 3 is a schematic block diagram showing one embodi
voltage . The output voltage clamp may include a control ment
of the isolated power supply system for an undersea
lable switch and a diode. The maximum desired output
communication cable of this invention used to create a
voltage may be about 10 V when the controller is not 10 branch
off of an undersea communication cable ;
energized . The input circuitry may include a current divider
FIG . 4 is a schematic block diagram showing one example
and the isolated DC -DC transformer circuit configured to
of the primary components of the isolated power supply
direct a fraction of the input current to the isolated DC - DC
system for an undersea communication cable shown in FIG .
transformer circuit. The current divider may be configured 15 3 ;
as a boost regulator including one or more of a diode, an
FIG . 5 shows a three - dimensional view of one example of
coupled between the communication cable power conductor
inductor, a controllable switch , and an isolated gate driver a prototype of the isolated power supply system 100 for an
undersea communication cable shown in FIGS. 2 - 4 ;
circuitry and the one or more outputs by pulse width
FIG . 6 is a circuit diagram showing in further detail one
modulation . The controller may be configured to provide a 20 example of the input circuitry of the one or more power
large DC ripple current for toning.
converters shown in FIGS. 4 -5 ;
In another aspect, a method for providing isolated power
FIG . 7 is a schematic block diagram showing in further
from a current carrying undersea communication cable to a
detail the primary components of isolated power supply
branch located off the undersea communication cable is system for an undersea communication cable shown in one
featured . The method includes providing one or more power 25 or more of FIGS 3 - 6
converters each including input circuitry responsive to input
FIG . 8 is a circuit diagram showing primary components
current from an undersea communication cable power con
of
another embodiment of the input circuitry of the one or
ductor , providing one or more outputs electrically isolated more
power converters shown in one or more of FIGS. 3 - 7 ;
circuit . The controller may be configured to control the input
from the communication power conductor, and controlling
FIG . 9 is a flowchart depicting one example of the
the operation of the one or more power converters to output
the one ormore outputs coupled to an external load located 30 primary steps of the isolated power supply method shown in
one or more of FIGS. 3 -7 ; and
off a branch of the undersea communication cable .
FIG . 10 is a flowchart depicting another example of the
In another embodiment, the controllingmay include con
trolling the operation of the variable DC -DC transformer primary steps of the isolated power supply method shown in
circuit to provide current limiting . The controlling may one or more of FIGS. 3 - 8 .
include controlling the operation of the variable DC -DC 35
DETAILED DESCRIPTION OF THE
transformer circuit to provide the output current . The con
INVENTION
trolling may include controlling the operation of the variable
DC -DC transformer circuit to provide voltage limiting . The
controlling may include controlling the operation of the
Aside from the preferred embodiment or embodiments
voltage. The controlling may include controlling the opera -
ments and of being practiced or being carried out in various
tion of the isolated DC -DC transformer circuit to provide
power
to the branch off the undersea communication cable .
The controlling may include controlling the operation of the
ways . Thus, it is to be understood that the invention is not
limited in its application to the details of construction and
the arrangements of components set forth in the following
variable DC -DC transformer circuit to provide the output 40 disclosed below , this invention is capable of other embodi
isolated DC -DC transformer circuit to provide power to a 45 description or illustrated in the drawings. If only one
load off the undersea communication cable . The method
embodiment is described herein , the claims hereof are not to
may include providing a fault protection circuit coupled to
be
to that embodiment.Moreover, the claims hereof
the communication cable power conductor and the isolated are limited
not to be read restrictively unless there is clear and
DC - DC transformer circuit configured to bypass fault cur
convincing evidence manifesting a certain exclusion , restric
rent around the input circuitry of one or more power 50 tion
, or disclaimer.
converters . The method may include providing an output
As discussed in the Background section above , conven
voltage clamp coupled to the isolated DC -DC transformer
tional system 10 , FIG . 1 , provides power to remotely located
circuit and the communication cable power conductor con repeater
stations 12 located at intervals along undersea
figured to limit the output voltage to a maximum desired
output voltage. The input circuitry may include a current
communication cable 14 , typically in inaccessible locations
Other objects , features and advantages will occur to those
located repeater stations 12 are typically spliced into under
sea communication cable 14 at the various repeater stations
divider coupled between the communication cable power 55 undersea . Power may be supplied to repeaters 12 by estab
conductor and the isolated DC - DC transformer circuit con - lishing a current flow through high voltage undersea com
figured to direct a fraction of the input current to the isolated munication cable 14 by connecting high voltage, low current
DC - DC transformer circuit. The controlling may include DC power supply 16 , e . g ., + 15 kV , 1 A , ofone polarity at one
controlling the input circuitry and the one or more outputs by
end of undersea communication cable 14 and high voltage
60 power supply 18 of opposite polarity at the other end of
pulse width modulation .
undersea communication cable 14 as shown. The individual,
BRIEF DESCRIPTION OF THE SEVERAL
low - voltage , low current power supplies 20 for remotely
VIEWS OF THE DRAWINGS
skilled in the art from the following description of a pre - 65 a shown . The necessary operating voltage at each remotely
ferred embodiment and the accompanying drawings, in
located repeater station 12 is developed by the voltage drops
which :
obtained across equivalent input resistances 22 of each
US 10 , 141,854 B1
successive power supply 12 . The total power to be supplied
to the system includes of the sum of the wattages developed
at each power supply 20 and in each segment of cable
undersea communication cable 14 . External load 120 typi
cally has an arbitrary and dynamically changing load imped
ance .
from a very high positive voltage at end 24 , falls steadily to
middle 26 , turns negative and continues to fall to a maxi
converter 116 as shown and is configured to control the
operation of power converter 114 and/or power converter
have it sustain damage without risk of a ground fault. See ,
e .g., U . S . Pat .No. 6 ,611,443 , by one or more of the inventors
output voltage , a regulated DC output voltage , an output
current, a programmable output current, and a regulated DC
resistance . The voltage level across high voltage undersea
Isolated power supply system 100 , FIG . 4 , also includes
communication cable 14 varies significantly to sea ground , 5 controller 130 coupled to power converter 114 and / or power
116 such that power converter 114 and/ or power converter
mum negative voltage at end 28 . Such a design stresses the
116
provides the one or more outputs 126 and/ or 128 . In one
cable insulation at its extremities and makes very difficult
or 10 example
w
, the one or more outputs 126 and /or 128 preferably
virtually impossible at most locations to breach the cable or
include one or more of an output voltage , a programmable
hereof and the Assignee hereof, incorporated by reference
current. In one example the output voltage , Vout- 262, may
herein .
15 be a voltage in the range of about 0 to 2 kV or higher and
Intercontinental undersea communication cable 14 may
the output current, lour- 264 , may be a current in the range
be utilized to transmit high speed digital signals over low
loss fiber optic fibers enclosed in undersea communication
of about 0 .1 A to about 5 A . Preferably the output voltage
and output current are provided to external load 120 located
on branch 132 off of undersea communication cable 14 .
cable 14 , e . g ., fiber optic fibers 38 , FIG . 2 , where like parts
have been given like numbers, enclosed in undersea com - 20 In one design , controller 130 may be a processor, such as
munication cable 14 as shown . In one example , repeaters 12 , a peripheral interface controller (PIC ) microprocessor or
FIG . 1 may be utilized to amplify and restore attenuated
light signals. Power may be delivered to repeaters 12 by high
voltage , low current DC power supplies 24 , 28 and power
supplies 20 as discussed above with reference to FIG . 1 , and 25
similar type processor. In other designs, controller 130 may
include or be configured as one or more processors , an
application - specific integrated circuit (ASIC ), firmware ,
hardware , and/ or software ( including firmware , resident
is typically carried to repeaters 12 by a single communica -
software , micro -code, and the like ) or a combination of both
tion cable power conductor, e . g ., communication cable
power conductor 40 , FIG . 2 , enclosed in undersea commu-
hardware and software that may all generally be referred to
herein as a " controller ” , “ module " , " engine " or " system ”
nication cable 14 . In one example , repeaters 12 are electri-
which may be part of controller 130 and isolated power
cally isolated from sea ground and are powered by the 30 supply system 100 . Computer program code for the pro
current flowing in communication cable power conductor 40 grams for carrying out the instructions or operation of one or
from one end of the undersea communication cable 14 to the
more embodiments of the isolated power supply system 100
other without regard to voltage to sea ground . There is often
for an undersea communication cable and controller 130 of
a need to create a branch from undersea communication
this invention may be written in any combination of one or
may be obtained without requiring completely separate
cables. Powering repeaters 12 in a branch can be problem atic since themain power conductor cannot be breached and
programming language , e . g ., C + + , Smalltalk , Java , and the
like, or conventional procedural programming languages ,
such as the “ C ” programming language or similar program
cable 14 so communication between more than two points 35 more programming languages, including an object oriented
the relative voltage to seawater at any particular point is
ming languages or in assembly code.
may have an arbitrary and dynamically changing resistance
ductor 40 , e . g ., by isolation transformer 150 . Isolated power
unknown , variable or not defined . Moreover, it may be 40 Preferably , the one or more outputs 126 and /or 128 are
desirable to supply power to a nearby external load which
electrically isolated from communication cable power con
or power such as undersea devices , equipment, and the like ,
supply system 100 also preferably includes main electronics
not related to the typical main function of the undersea
communication cable .
board 136 , e .g ., a printed circuit board or similar type
45 electronics board that includes at least power converter 114
There is shown in FIG . 3 , where like parts have been
given like numbers, one embodiment of the isolated power
and /or power converter 116 and controller 130 thereon and
is coupled to transformer 150 . Isolated power supply system
supply system 100 for an undersea communication cable ,
100 also preferably includes secondary electronics board
such as undersea communication cable 14 . In this example ,
152, e . g ., a printed circuit board or similar type electronics
unlike conventional power supplies 20 which are not iso - 50 board , coupled to transformer 150 as shown . In one design ,
lated from undersea communication cable 14 , isolated
secondary electronics board 152 preferably includes rectifier
power supply system 100 for an undersea communication
indicated at 102, as discussed in detail below . Isolated power
been given like numbers , shows a one example of a proto
nication cable 14 , as shown, e. g .between positive input 122
mounted to the printed circuit board as shown .
also includes one or more outputs , e . g ., output 126 and /or
116 are each preferably configured to control current or
cable is isolated from undersea communication cable 14 as
154 , filter 156 and clamp 158 . FIG . 5 , where like parts have
type of one embodiment of isolated power supply system
supply system 100 includes one or more power converters, 55 100 with power converter 114 , power converter 116 , and
e . g ., power converter 114 , FIG . 4 , and/ or power converter
controller 130 shown mounted on main electronics board
116 , each including input circuitry 118 in series with com 136 and coupled to isolation transformer 150 and secondary
munication cable power conductor 40 of undersea commuelectronics board 152 with rectifier 154 and filter 152
and negative input 124 . Isolated power supply system 100 60
Power converter 114 , FIGS. 3 -5 , and/ or power converter
output 128 , in this example, positive and negative , respec -
voltage with input circuitry 118 to provide one or more
tively, as shown , and each electrically isolated from com
outputs 126 and/or 128 . In one example, input circuitry 118
munication cable power conductor 40 , e . g ., by isolation
of power converter 114 and /or power converter 116 provides
transformer 150 as shown, and preferably coupled to exter - 65 a regulated DC voltage and then chops it into AC . The AC
nal load 120 , FIGS. 3 and 4 , such as undersea devices ,
goes through isolation transformer 150 for isolation and is
equipment, and the like , located on branch 132 off of rectified by rectifier 154 and filtered by filter 156 to produce
US 10 , 141, 854 B1
the desired regulated DC output, e .g., Vout- 262 and /or
lour - 264, FIG . 4 , at the one or more outputs 126 , 128 .
Clamp 158 preferably coupled to one ormore output 126 ,
128 ensures that communication cable power conductor 40
In one example, controller 130 , FIG . 6 , coupled to con
trollable switches 170 of modulated converter 140 and
controllable switches 160, 162 of inverter 142 is preferably
configured to provide the DC voltage VR- 146 .
is discharged for worker safety. Clamp circuit 129 coupled 5 FIG . 7 , where like parts have been given like numbers,
in further detail one embodiment of the various
to input 122 preferably diverts surge current around power shows
components of system 100 . In this example, system 100
converter 114 and /or power converter 116 during a cable
includes two identical power converters 114 , 116
fault (discussed in further detail below ). One common event preferably
each
with
input circuitry 118 and sections configured as
may be a fishing boat snagging undersea communication 10 modulated converter
and inverter 142 , e .g., as discussed
cable 14 and damaging the insulation which may result in a above with reference140
to
FIG . 6 , power supply or voltage
power supply short to sea ground. The transient current from
regulator
271
,
FIG
.
7
,
e
.
g
.
a 5 V power supply which are all
this event can be as large 750 A . Therefore , everything preferably controlled by ,controller
130 . Controller 130 is
powered by undersea communication cable 14 needs to
preferably responsive to the input voltage A -232 from power
survive these transients so that repairs to the damaged 15
ged 15 converter 114 , e. g ., Viv - 144 , FIG . 6 , input voltage B - 234 ,
FIG . 7 , from power converter 116 , e .g ., Vi - 144 , input
section allow the cable to continue to operate .
In one design , input circuitry 118 of each power converter
114 and/ or power converter 116 preferably includes a plu rality of sections, e. g ., section 140 , FIG . 6 , where like parts
current 234 , e .g., Iin - 250 , and output current 238 , e.g.,
I - 252 . As discussed above , modulated converter 140
produces the output voltage , e .g ., a regulated DC voltage or
have been given like numbers, and section 142 , which are 20 a programmable output voltage, Vr-146 . Controller 130
preferably configured to divide input voltage, Vin - 144 , from
may also be responsive to an arbitrary and dynamically
140 , 142 . In one design , section 140 may be configured as
branch off the undersea communication cable 110 , FIG . 1 .
a modulated converter, e . g ., a pulse width modulator or
In operation , as power converter 114 , FIGS. 4 - 7 , and
communication cable power conductor 40 between sections
changing external load impedance 220 located on 132
similar type modulator to provide regulated DC voltage 25 power converter 116 are powered by a current source , e . g .,
VR- 146 . In one example , modulated converter 140 prefer-
regulator 270, modulated converter 140 , FIG . 6 , preferably
ably includes one or more controllable switches, e . g ., con
trollable switch 170 , such as a silicon carbide metal oxide
provides regulated DC voltage , VR - 146 , which is then fed to
inverter 142 . Each inverter 142, one for power converter
field effect transistors MOSFETs or similar type controllable
114 , FIG . 4 , and one of power converter 116 drives primary
switch , coupled to controller 130 as shown such that modu - 30 winding 192 , 194 respectively on isolation transformer 150 .
lated converter 140 provides regulated DC voltage VR - 146 .
Voltage sharing between power converter 114 and power
In this example , modulated converter 140 also preferably
converter 116 may be enforced by shared transformer core
176 , FIGS. 4 and 6 . Modulated converters 140 , FIG . 6 , of
includes diode 172 and capacitor 174 .
In one example , section 142 may be a configured as an
power converter 114 and power converter 116 are preferably
VR- 146 . In one example , inverter 142 may be a square wave
Preferably, power converters 114 , 116 are driven together
inverter or similar type inverter and preferably includes one
or more controllable switches, e.g ., controllable switches
160 and 162 which may be a silicon carbide metal oxide
field effect transistors (MOSFETs ) or similar type control- 40
vided by controller 130 and controllable switches 160 , 162,
and 172 . The duty factor of the PWM is preferably used to
regulate each of power converters 114 , 116 . Input voltage ,
inverter or chopper responsive to the regulated voltage , 35 wound on the same core 176 to ensure voltage sharing .
from a single Pulse Width Modulation (PWM ) output pro
lable switches . Controllable switches 160 , 162 are coupled
to controller 130 as shown to drive transformer primary
Viv - 144 , is preferably shared between power converter 114
and power converter 116 , which each may be 1200 V power
circuit 166 which preferably includes isolation transformer
converters which can be utilized up to 2400 V , but preferably
162 . In one design , controller 130 may be coupled to
minimizes the voltage isolation needed between the power
150 , core 176 and capacitor 168 configured such that con clamped to about 1500 V . Preferably controller 130 and
trollable switches 160 , 162 may open at low voltages , e . g ., 45 voltage regulator 271, FIG . 7 , are located between power
a voltage or bias voltage across controllable switches 160 ,
converters 114 , 116 as shown. Such a design preferably
modulated converter 140 and inverter 142 by magnetically
isolated gate drives.
converters 114 , 116 and controller 130 .
In one design , controller 30 , FIG . 6 , is preferably coupled
Transformer core 176 , FIGS . 4 and 6 , of isolation trans - 50 to controllable switches 160, 162 and 170 and an arbitrary
former 150 is preferably gapped to allow controllable
switches 160, 162, FIG . 6 , of inverter 142 to close at
approximately zero voltage . The core gap , typically formed
and dynamically changing external load impedance 130
located on branch 132 off of undersea communication cable
12 , FIGS. 3 and 4 , as shown. In this example , controller 130 ,
by inserting a spacer less than about 1 mm thickness FIG . 6 , is preferably configured to measure input current,
primary magnetizing current. This current forces the trans - regulated DC output voltage, VR - 146 , regulated DC output
former voltage to the opposite rail when one of the half voltages 126 , 128 , Vout- 262 , the desired regulated DC
bridge drive transistors 160, 162 open . The voltage across current, LOUT- 264 and the external load resistance of external
the other transistor is forced to zero , greatly reducing the load 120 . In this example, controller 130 is preferably
60 configured to adjust the duty cycle of switching of the
switching loss.
One or more outputs 126 , 128 are preferably actively controllable switches 160 and 162 of inverter 142 and
clamped by clamp 158, FIG . 4 , to a small voltage when an
controllable switch 170 of modulated converter, such that
input is not powered on . During handling and testing before the one or more outputs 126 , 128 provide the desired
between the two core sections, increases the transformer 55 Iv - 250 , of communication cable power conductor 40 , the
installation , it is preferable to have the output voltage be regulated voltage , Vout- 262 , or the desired regulated DC
held low . This allows testing of interconnections without the 65 current discussed above to external load 220 .
possibility of generating hazardous voltage during factory
and shipboard testing.
Preferably , input circuitry 118 of power converter 114
and /or power converter 116 includes bypass capacitor 190
US 10 , 141, 854 B1
configured to localize power supply transients to minimize
10
initially carries the full cable fault current from communi
interference with other electronics .
cation cable power conductor 40 and limits the voltage to
Field Effect Transistors (MOSFETs), Insulated Gate Bipolar
a safe value .
Preferably, system 100, FIGS. 3 - 6 , is housed in a pressure approximately twice the maximum nominal voltage, e. g .,
vessel which may be sealed and filled with oil, pressurized
about 1 , 200 V to about 2 ,400 V , or higher or lower voltages
air, or nitrogen for electrical insulation and heat transfer. 5 as known by those skilled in the art. Zener diode 242 may
Preferably, controllable switches 160, 162 and 170 may
not necessarily carry the fault current for the entire duration
include Field Effect Transistors (FETs ), silicon Metal Oxide
of a fault event and may not necessarily limit the voltage to
Transistors (IGBTs ), field effect transistor controlled Thy .
In one example , input circuitry 118 preferably includes
ristors (MCTS ) Gate Run Off Thyristors (GTOs ), and Power 10 fault protection circuit 240 coupled to isolated DC -DC
Darlingtons.
transformer circuit 200 and communication cable power
In one embodiment, isolated power supply system 100 for
an undersea communication cable may include power con -
conductor 40 configured to limit the input voltage to a
maximum desired input voltage . In one design , input cir
verter 114 and /or power converter 116 each with input cuitry 118 may include input filter 256 preferably includes
circuitry 118 , FIG . 8 , where like parts have been given like 15 inductor 246 , diode 248 and capacitor 250 . Input filter 256
numbers . In this example , input circuitry 118 preferably
preferably limits the rate of rise of the voltage on switching
includes isolated variable DC - DC transformer circuit 200 . In
device 252 so that all voltage remains at safe levels until
one design , isolated variable DC -DC transformer circuit 200
controller 130 can turn on switching device 252. Switching
isolated gate driver circuit 210 , isolation transformer 150 ,
a fault event.
and 224 and diode 226 coupled in the exemplarily configu -
ate during the cable fault and turns switching device 252 off
preferably includes switching device 202 , isolated gate
device 252 may be several devices in parallel and is pref
driver circuit 204 , capacitor 206 , switching device 208 , 20 erably rated to carry the full cable current for the duration of
capacitor 212 , diode 216 , inductor 218 , capacitors 220 , 222 ,
Preferably , fault protection circuit 240 continues to oper
ration as shown . Switching devices 202 and 208 may be when the fault current has reduced to the normal operating
MOSFETs or similar type switching devices as discussed 25 current.
above. Isolated gate drive circuits 204 and 210 may be any
Isolated DC -DC transformer circuit 200 of input circuitry
of several commercially available isolated gate driver cir cuits (e . g ., UCC 21520 available from Texas Instruments,
118 preferably includes rectifier circuit 154 as discussed
above with reference to FIG . 4 which in this example
Dallas Tex . ) which can directly drive power transistors with
includes diode 216 , FIG . 8 , capacitors 220 , 222 , and diode
acceptable delays and can stand off the DC voltages up to 30 226 . Isolated variable DC -DC transformer circuit 200 also
1500 Volts for more than 25 years .
preferably includes filter 156 as discussed above with ref
In one design , controller 130 preferably controls the
operation of isolated DC -DC transformer circuit 200 to
provide current limiting . Controller 130 may also control the
erence to FIG . 4 which in this example preferably includes
i nductor 218 and capacitor 224 .
Input circuitry 118 preferably include output voltage
operation of variable DC -DC transformer circuit to provide 35 clamp 158 as discussed above with reference to FIG . 4 . In
output current I_ our- 264, e . g ., a regulated DC current or a
this example , output voltage clamp 158 , FIG . 8 , preferably
programmable output current. Controller 130 may also be
configured to control the operation of variable DC -DC
transformer circuit 200 to provide voltage limiting. Control
includes resistor 300, switching device 302 , e.g ., a MOSFET
or similar type switching device, and isolated gate driver
circuit 304 . Preferably, output voltage clamp 158 is config
ler 130 may also control the operation of variable DC -DC 40 ured such that the maximum desired output voltage , VOUT
transformer circuit 200 to provide output voltage, Vour
262, is about 10 V when controller 130 is not energized .
output voltage .
circuit 200 of input circuitry 118 may include current divider
or voltage regulator 270 , e .g ., as discussed above with
262, e . g ., a regulated DC output voltage or a programmable
In one design , controller 130 is configured to control the
In one example, isolated variable DC -DC transformer
operation of isolated DC -DC transformer circuit 200 to 45 reference to FIG . 7 , which is preferably coupled between
provide power to branch 132 , FIGS. 3 and 4 , located off
communication cable power conductor 50 and isolated DC
undersea communication cable 14 or provide power to load
DC transformer circuit 200 , FIG . 8 , as shown. In one design ,
130 , of an arbitrary and dynamically changing impedance .
current divider or voltage regulator 270 may be program
In one design , input circuitry 118, FIGS. 3 -8 ,may include mable and preferably includes one or more of inductor diode
fault protection circuit 240 , FIG . 8 , coupled to communica - 50 272 , inductor 274 , switching device 276 , e . g ., a MOSFET or
tion cable power conductor 40 and isolated DC -DC trans former circuit 200 as shown configured to bypass fault
current around input circuitry 118 of power converter 114
and/ or power converter 116 . Fault protection circuit 240
similar type device , capacitor 278 and isolated gate driver
circuit 280. Voltage regulator 270 is preferably configured to
direct a fraction of the input current from communication
cable power conductor 40 to isolated DC -DC transformer
device 252, e .g ., a MOSFET or similar type switching
device , and optional isolated gate driver circuit 254 . Cable
fault current can be in either direction . When the fault
current is reversed of normal polarity, diode 244 conducts
regulator 270 is configured as a boost regulator as shown .
Preferably , power converter 114 and/ or power converter
116 , shown in one or more of FIGS. 4 - 8 , each with input
circuitry 118, are connected in series with communication
preferably includes Zener diode 242, diode 244, switching 55 circuit 200 . In one design , the current divider or voltage
the full current with a voltage drop until current reverses to 60 cable power conductor 40 .
the normal polarity . Diode 248 disconnects the power cir -
In one exemplarily operation of isolated power supply
cuitry while the current is reversed. Although in this
system 100 , FIGS. 3 -8 , for an undersea communication
example , diode 244 is shown in parallel with Zener diode cable, a nominal 1 A current flows between positive input
242, this is for exemplary purposes only , as diode 244 may
122, FIG . 8 , and negative input 124 . Controller 130 controls
be placed directly across of the chain of conductors . Zener 65 the state of transistors 252 , 276 , 202 , 208 , and 302 using
diode 242 is preferably a voltage limiting device , e . g ., a
isolated gate driver circuits 254 , 280 , 204 , 210 , and 304 ,
metal oxide varistor (MOV ) or similar type device which
respectively . Both power circuits are identical and prefer
US 10 , 141, 854 B1
ably have the same control signals . Controller 130 is pref
erably powered by voltage regulator 271 designed to tolerate
the cable fault current. At start-up , either isolated gate driver
circuit 254 or isolated gate driver circuit 280 includes
12
turns ratio of isolation transformer 150 . Preferably inductor
218 and capacitor 224 form filter 156 , as discussed above ,
e .g., an output ripple filter. The transformer ratio of isolation
transformer 150 is preferably selected to determine the
circuitry to turn on its associated switching device ( switch - 5 maximum output voltage and current provided at outputs
ing device 252, switching device 276 , respectively in the
126 , 128 . Isolated gate driver circuit 304 is preferably
absence of gate power. This allows cable current to flow
designed so that switching device 302 of output voltage
through voltage regulator 270 at start-up . The normal idle
clamp 158 is turned on unless controller 130 actively turns
state of switching device 276 is continuously on providing
it off. This is preferably used for safety during installation
a minimum voltage drop to communication cable power 10 and testing of system 100 .
conductor 40.
Once the controller 130 is active , controller 130 turns
Typically, system 100 utilizes two power stages , one
connected to positive input 122 of the control section and
switching device 276 on for minimum idle voltage drop and
one connected to negative 124 , e . g ., as shown in FIG . 4 .
power consumption . When controller 130 receives a request
Preferably, the current from communication cable power
for output voltage or current to be provided at outputs 126 , 15 conductor 40 flows through the series connected power
128 , controller 130 turns switching device 252 off and
switching device 302 off and begins PWM of switching
converter 114 and / or power converter 116 and control 130 as
shown . In this example , inductor 274 is preferably wound
device 276 and operates switching devices 202 and 208 as
with two separate coils and isolation transformer 150 has
a square wave inverter 330 driving primary 350 of isolation two separate primary windings, e.g., primary windings 192 ,
transformer 150 . The PWM action of switching device 276 20 194 .
sends cable current to capacitor 278 for some fraction of the
Preferably, isolated gate driver circuit 254 turns on
time. This fraction of time is preferably variable and allows switching device 252 when the input voltage exceeds a
the output current at outputs 126 , 128 to be any desired threshold or increases too rapidly and may also be held on
fraction of the line current of communication cable power by controller 130 . This allows rapid activation and con
conductor 40 from zero to about 1 A . Inductor 274 prefer - 25 trolled release of fault protection circuit 240 . Isolated gate
ably controls the rate of change of current into switching
driver circuit 280 , 204 , and 210 may any of several com
device 276 and diode 272 . Although in this example, voltage
mercially available isolated gate driver circuits ( e .g ., UCC
regulator 270 as discussed above is the same as a classic
21520 available from Texas Instruments , Dallas Tex.) which
boost converter , in this example , voltage regulator 270
can directly drive power transistors with acceptable delays
functions to steer a fraction of the current from communi- 30 and can stand off the DC voltages up to 1500 Volts for more
cation cable power conductor 40 into capacitor 278 . The than 25 years . Isolated gate driver circuit 304 is preferably
duty factor of switching device 276 changes slowly to avoid
the only isolated gate driver circuit which needs to withstand
transient problems. If the load current suddenly drops, the
the voltage on communication cable power conductor 40 to
switch 252 needs turn on quickly to avoid an overvoltage
sea ground 380 . Preferably , isolated gate driver circuit 304
condition . The maximum voltage on capacitor 278 is deter- 35 is a fiber optic coupled phototransistor which keeps clamp
mined by the voltage rating of the switching devices . The
switching device 302 turned off under control of the con
voltage on capacitor 278 times the cable current is the input
power for each power circuit.
Preferably the voltage across capacitor 278 is converted to
AC by the switching devices 202 and 208 functioning as a 40
troller 130 . Communication between the controller 130 and
chopper which excites primary winding 350 of isolation
transformer 150 . Capacitors 206 and 212 preferably resonate
with the leakage inductance of isolation transformer 150 so
that switching devices 202 and 208 turn off at nearly zero
current. The magnetizing inductance of isolation trans - 45
former 150 may be controlled by a core gap so that the
magnetizing current can charge and discharge the output
capacitance of switching device 202 and 208 . This allows
switching devices 202 and 208 to turn on at zero voltage
Switching at zero voltage and zero current is a well -known 50
the shore may be via a local fiber optic signal link from the
repeater electronics housed in the same pressure vessel. The
output section discussed above preferably delivers output
voltage and current feedback information to controller 130
by an optical fiber or transformer isolated link .
Although the configuration of inductor 246 , capacitor
250 , switching device 252 , and diode 248 of fault protection
circuit 240 have the same configuration as inductor 274 ,
capacitor 278 , switching device 276 and diode 272 of
voltage regulator 270 these circuits never operate at the
same time. Switching device 252 is preferably a high current
device capable of carrying cable fault transients of up to 750
A . Switching device 276 is preferably a low current device
technique to minimize switching losses.
Preferably isolation transformer 150 isolates the primary
optimized for switching efficiency at the normal cable
current of approximately 1 A . Similarly, diode 248 and diode
circuit , e. g., fault protection circuit 140 , voltage regulator
244 are preferably high current diodes and diodes 272, 216 ,
270 and inverter 330 of isolated variable DC -DC trans and 226 are low current, low switching loss diodes .
former circuit 200 , which is at the voltage of communication 55 FIG . 9 shows one exemplary flowchart of the operation of
cable power conductor 40, e. g., as high as about 15 kV, from
controller 130 of isolated power supply system 100 and the
sea ground 380 . The secondary circuit including part of
method thereof. In this example , sufficient cable current
isolated variable DC -DC transformer circuit 200 as shown
from communication cable power conductor 40, FIG . 7 ,
cation cable power conductor 40. In one design , diodes 216 ,
analog - to -digital conversion (ADC ) 406 , PWM 408, timer
be approximately the voltage on capacitor 278 times the
no , indicated at 422, step 420 is repeated . If yes , indicated
coupled to secondary winding 352 of isolation transformer powers voltage regulator 271 which wakes controller 130
150, rectifier 154, filter 156 , and output voltage clamp 158 60 and voltage regulator 271 provides voltage to controller 130 ,
as discussed above is referenced to sea ground 380 and
step 400 , FIG . 9 . One exemplarily configuration of control
insulated from the components connected to the communi - ler 130 includes one or more of ports 402, clock 404 ,
226 , and capacitors 220 , 222 form a full wave voltage
410 , interrupts 412 , and Universal Asynchronous Receiver/
65 Transmitter (UART) 414 . A determination is made whether
doubler.
The DC output voltage provided at outputs 126 , 128 may
or not the input current is above the threshold , step 420 . If
US 10 ,141,854 B1
14
SET BYPASS _MODE = ' u ',
13
at 424 , bypass state 426 is initiated . Bypass state preferably
includes turning off a control loop , indicated at 428 , deter
mining if the input is shorted , indicated at 430 , determining
SET _ OUTPUT_ CLAMP = ' V ',
CLEAR OUTPUT_ CLAMP= ' w ' ,
if whether or not inverter 330 , FIG . 9 , functioning as a
chopper is off , indicated at 432 , and determining whether or 5
not output voltage clamp 158 , FIG . 8 , is off , indicated at 434 ,
FIG . 9 . If a clamp is needed , step 450 , then a clamp state 452
is provided and bypass command 454 is provided . If bypass
state 426 is not required , then run transition 462 is initiated .
Run transition 462 preferably resets the integrator, indicated 10
at 464. The integrator is preferably part of the PID control
loop and may be implemented using software on controller
SET _ RUN _MODE = 'x ',
GET MODE = ' y ' ,
GET VIN = 'z ',
GET IIN = ' A ',
GET_ VOUT = ' B ',
GET _ IOUT = ' C ' ,
SET _ V _ RAMP = D ',
SET _ I_RAMP =“ E ',
GET
_ V _RAMP = F ',
130 and determines whether or not the input current can run
GET
_ I_ RAMP = ' G '
above the threshold , indicated 466 . If yes, indicated at 468,
"
a
z
”
and “ A -G ” are exemplary implementations of a test
a run state 470 is provided and the main chopper or inverter 15 communication
protocol where each command is preferably
330, FIG . 8 , is turned on , indicated at 472, the control loop
is turned on indicated at 474 . and a ramp to the output set
matched to a character sent over serial to controller 130 . For
point is achieved , indicated at 476 . Once in the run state , a
example , to set the input voltage , the character “ h ” is sent to
indicated at 482 . Steps 450 , 454, 460, 480, and 482 are
preferably commands received by controller 130 over serial.
In one example , the method for providing isolated power
controller 130 would respond with a value .
Major commands:
report output voltage and current
determination is made whether or not bypass state 426 is controller 130 followed by the requested value , or to query
needed , indicated at 480 , or if clamp state 452 is needed , 20 VOUT, the value “ B ” would be sent to controller 130 and
from a current carrying undersea communication cable to a
report internal voltages , currents , temperature
branch located off the undersea communication cable 25
ramp output voltage at rate to final voltage
includes providing one or more power converters each
ramp output current at rate to final current
including input circuitry responsive to input current from an
enter bypass mode (disable converter )
undersea communication cable power conductor, step 500,
FIG . 10 , providing one or more outputs electrically isolated
from the communication power conductor, step 502 , and 30
When active :
read voltage and current
update PWM (Pulse Width Modulator) duty factor as
controlling the operation of the one or more power convert -
needed to minimize difference between output voltage or
ers to output the one ormore outputs coupled to an external
current and commanded value
load located off a branch of the undersea communication
If output voltage is greater than limit, enter shutdown
cable , step 504 .
mode , send status
For enablement purposes only , the following code portion 35 decode and execute input commands as received
is provided which can be executed by controller 130 to carry
out the primary steps and /or functions of the controller 130
discussed above with reference to one or more of FIGS. 3 -8
and recited in the claimshereof. Other equivalent algorithms
and code can be designed by a software engineer and/or 40
programmer skilled in the art using the information provided
herein .
pseudocode for power supply
45 some drawings and not in others , this is for convenience
only as each feature may be combined with any or all of the
other features in accordance with the invention. The words
" including ” , " comprising ” , “ having" , and "with ” as used
wait for line current to reach threshold
wait for command
Complete Command list :
herein are to be interpreted broadly and comprehensively
GET _ VIN _ SET = ' a ',
GET_ IOUT_ SET = ' b ',
GET_ VOUT_ SET = ' c ',
50 and are not limited to any physical interconnection . More
over , any embodiments disclosed in the subject application
are not to be taken as the only possible embodiments . Other
GET _ OUTPUT_ INT= ' e ',
SET _ IOUT =' f',
SET_ VOUT = 'g ',
SET_ VIN = 'h ',
SET_ VIN _ KP = "i',
SET_ VIN _ KI= 'j',
SET _ VOUT_ KP = 'k ',
SET _ VOUT_ KI= '1',
SET_ IOUT_ KP = “ m ',
SET JOUT_ KI= ' n ',
GET_ VIN _ KP = " o ',
GET VIN _ KI= ' p ',
GET_ VOUT_KP = ?q ’,
GET _ VOUT_ KI= * r',
GET_ IOUT_ KP = ' s ',
GET _ IOUT_KI= 't ,
repeat loop
Interrupts :
command byte received
Byte transmitted
ramp timer
ADC conversion complete
Although specific features of the invention are shown in
on processor power up reset :
set bypass mode ( disables converter )
If input current drops below threshold , enter shutdown
mode
embodiments will occur to those skilled in the art and are
within the following claims.
55
In addition , any amendment presented during the pros
ecution of the patent application for this patent is not a
disclaimer of any claim element presented in the application
as filed : those skilled in the art cannot reasonably be
expected to draft a claim that would literally encompass all
60 possible equivalents , many equivalents will be unforesee
able at the time of the amendment and are beyond a fair
interpretation of what is to be surrendered ( if anything ), the
rationale underlying the amendment may bear no more than
a tangential relation to many equivalents , and /or there are
65 many other reasons the applicant cannot be expected to
describe certain insubstantial substitutes for any claim ele
ment amended .
US 10 , 141, 854 B1
15
16
12 . The system of claim 3 in which the output voltage
What is claimed is:
1 . An isolated power supply system for an undersea clamp includes a controllable switch and a diode .
communication cable comprising :
13. The system of claim 12 in which the maximum desired
one or more power converters each including input cir- output voltage is about 10 V when the controller is not
cuitry including a modulated converter including one or 5 energized .
more controllable switches followed by an inverter
14 . The system of claim 3 in which the input circuitry
including one or more controllable switches responsive
to an input current from a communication cable power
conductor and in series with the communication cable
includes a current divider coupled between the communi
cation cable power conductor and the isolated DC -DC
transformer circuit configured to direct a fraction of the
power conductor of the undersea communication cable ; 10 input current to the isolated DC -DC transformer circuit .
one or more outputs electrically isolated from the com -
15 . The system of claim 3 in which the current divider is
configured as a boost regulator including one or more of a
diode , an inductor, a controllable switch , and an isolated gate
munication cable power conductor; and
a controller coupled to each of the one or more power
converters, the controller configured to control the
driver circuit .
operation of the one or more power converters to 15 16 . The system of claim 3 in which the controller is
provide the one ormore outputs coupled to an external configured to control the input circuitry and the one ormore
load located on a branch off of the undersea commu - outputs by pulse width modulation .
nication cable , the controller coupled to the one ormore
17. The system of claim 3 in which the controller is
on the branch of the undersea communication cable, the
each of the one or more power converters includes a
controllable switches of the inverter, an arbitrary and
configured to provide a large DC ripple current for toning .
dynamically changing external load impedance located 20 18 . The system of claim 1 in which the input circuitry of
controller configured to measure the input current com - plurality of sections configured to divide the input voltage
munication cable power conductor, a regulated DC
from the communication cable power conductor between the
voltage output by the modulated converter, a desired
sections.
regulated DC output voltage , a desired regulated DC 25 19 . The system of claim 1 in which the controller is
current, and an external load impedance and configured
coupled to the input circuitry of each of the one or more
to determine and adjust the duty cycle of switching of power converters by magnetic isolation .
the controllable switches of the modulated converter
20 . The system of claim 1 in which the controller is
and the inverter such that the desired regulated DC
configured to control the operation of the input circuitry of
output voltage and /or the desired regulated DC current 30 each of the one or more power converters by pulse width
is provided to the external load impedance .
modulation .
2 . The system of claim 1 in which the one or more outputs
21 . The system of claim 1 in which the one or more
includes one or more of: an output voltage, a programmable
outputs are electrically isolated from the communication
output voltage , a regulated DC output voltage , an output
cable power conductor by an isolation transformer.
current, a programmable output current, and a desired regu - 35
22 . The system of claim 1 in which the input circuitry of
each of the one or more power converters includes a bypass
3 . The system of claim 2 in which the input circuitry and
capacitor.
each of the one or more power converters includes an
23 . The system of claim 1 in which the switching of the
controllable switches by the controller includes pulse width
isolated variable DC -DC transformer circuit.
4 . The system of claim 3 in which the controller is 40 modulation .
lated DC current .
configured to control the operation of the variable DC -DC
transformer circuit to provide current limiting .
24 . The system of claim 1 further including a voltage
regulator coupled to the one or more power converters and
5 . The system of claim 3 in which the controller is
configured to control the operation of the variable DC -DC
the controller configured to provide power to the one or
more power converters and the controller.
45 25 . The system of claim 1 in which the one or more power
transformer circuit to provide the output current .
6 . The system of claim 3 in which the controller is
configured to control the operation of the variable DC -DC
transformer circuit to provide voltage limiting .
converters includes a plurality of power converters .
26 . The system of claim 1 in which the branching unit is
housed in a pressure vessel.
7 . The system of claim 6 in which the controller is
27 . The system of claim 1 further including a fault
configured to control the operation of the variable DC -DC 50 protection circuit coupled to the communication cable power
conductor and the isolated DC - DC transformer circuit con
transformer circuit to provide the output voltage .
8 . The system of claim 3 in which the isolated DC -DC
figured to bypass fault current around the input circuitry of
transformer circuit includes a programmable voltage regu
one or more power converters.
lator .
28 . The system of claim 1 in which the inverter is
9 . The system of claim 3 in which the controller is 55 configured to drive transformer primary circuit including an
configured to control the operation of the isolated DC -DC
isolation transformer, the transformer core, and a capacitor
transformer circuit to provide power to the branch off the
undersea communication cable .
to allow switches of the inverter to open at low currents.
29 . The system of claim 28 in which the inverter includes
10 . The system of claim 3 in which the controller is
a square wave inverter .
configured to control the operation of the isolated DC -DC 60 30 . The system of claim 28 in which the transformer core
transformer circuit to provide power to a load off the
undersea communication cable .
is gapped to allow switches of the inverter to close at zero
voltage .
11 . The system of claim 3 further including an output
voltage clamp coupled to the isolated DC -DC transformer
31 . The system of claim 1 in which the controllable
switches of the modulated converter and the inverter
figured to limit the output voltage to a maximum desired
output voltage .
carbide metal oxide , field effect transistors (MOSFETs),
insulated gate bi- polar transistors ( IGBTs ), field effect tran
circuit and the communication cable power conductor con - 65 includes one or more of : field effect transistors , silicon
US 10 , 141, 854 B1
17
sistor controlled Thyristors (MCTs), gate runoff Thyristors
18
36 . The method of claim 32 in which the controlling
(GTO ), and power Darlingtons .
includes controlling the operation of the variable DC -DC
32 . A method for providing isolated power from a current transformer circuit to provide the output voltage .
carrying undersea communication cable to a branch located
37. The method of claim 32 in which the controlling
off the undersea communication cable , the method comprissa- 55 :includes
controlling the operation of the isolated DC -DC
ing:
transformer
circuit to provide power to the branch off the
providing one or more power converters each including
undersea communication cable .
input circuitry responsive to input current from an
undersea communication cable power conductor ;
providing one or more outputs electrically isolated from
the communication power conductor ; and
controlling the operation of the one or more power
38 . The method of claim 32 in which the controlling
includes controlling the operation of the isolated DC - DC
transformer circuit to provide power to a load off the
undersea communication cable .
converters to output the one or more outputs coupled to
an external load located off a branch of the undersea
communication cable by measuring an input current
39 . Themethod of claim 32 further including providing a
fault protection circuit coupled to the communication cable
15 power conductor and the isolated DC -DC transformer circuit
communication cable power conductor a regulated DC 15
voltage output by a modulated converter, a desired configured to bypass fault current around the input circuitry
regulated DC output voltage, a desired regulated DC
current, and an external load impedance and determin -
ing and adjusting the duty cycle of switching of con
of one or more power converters .
40 . The method of claim 32 further including providing an
output voltage clamp coupled to the isolated DC -DC trans
trollable switches of a modulated converter and an 20 former circuit and the communication cable power conduc
inverter such that the desired regulated DC output
voltage and/ or the desired regulated DC current is
provided to the external load impedance .
tor configured to limit the output voltage to a maximum
desired output voltage .
41. The method of claim 32 in which the input circuitry
33 . The method of claim 32 in which the controlling
includes a current divider coupled between the communi
including controlling the operation of the variable DC -DC 25 cation cable power conductor and the isolated DC - DC
transformer circuit to provide current limiting.
transformer circuit configured to direct a fraction of the
34 . The method of claim 32 in which the controlling input
current to the isolated DC -DC transformer circuit .
includes controlling the operation of the variable DC -DC
transformer circuit to provide the output current.
35 . The method of claim 32 in which the controlling
includes controlling the operation of the variable DC -DC
transformer circuit to provide voltage limiting .
42. The method of claim 32 in which the controlling
30 includes controlling the input circuitry and the one or more
outputs by pulse width modulation .
*
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