SUBMARINE POWER DISTRIBUTION BY SMART DC MICROGRID

UDT 2020Peter Rampen – Principal Research Engineer E&A

22 m, 77 / 85 mt

2x 22 kW electric propulsion

speed: 7.8 / 3 kts

DC ON SUBMARINE IN 1889

PAST

2

613 batteries (50 kg each, 30 mt total)

only shore charging

range 400 nmi (@ 3 kts)

“Edison DC”

AGENDA

3

1. LIMITATION OF CURRENT DC SYSTEMS

2. SMART DC TECHNOLOGY

3. SUBMARINE SMART DC SOLUTIONS

4. TRADE OFF REVIEW

5. CONCLUSIONS

large variable voltage large currents

DC motors

very large circuit breakers

all aux. loads on AC

“Edison DC+” (some solid state

converters)

Batteries determine DC voltage:

all equipment rated for voltage range:

current rating at min. voltage

means 2x larger

WALRUS CLASS POWER

NOW

4

M

G

G

switc

hboa

rd

M G

M G

lead acid lead acid

400Vac50Hz

115Vac400Hz

250..600Vdc

large variable voltage large currents

large DC circuit breakers

some large loads on DC

many others at AC or 24Vdc

2-split system for reliability not ideal

TODAY

NOW

5

MPM

G

G

pro

pu

lsio

n s

wit

chb

oa

rd

400Vac50Hz

24Vdc

ma

in s

witc

hb

oa

rd

250...600Vdclead acid lead acid

400Vac50Hz

24Vdc

250...600Vdc

250..600Vdcaft zone fwd zone

Batteries determine DC voltage:

all equipment rated for voltage range:

current rating at min. voltage

means 2x larger

DC ON COMMERCIAL SURFACE VESSELS

NOW

6

M M M

Fast charging shore connection

450kW

Overnight charging connection

20kWESS290kWh

M

≈ 500-800V

NC

NO

24V

BT50kW

1300rpm

Prop 170kW 700rpm

(100kW@1000rpm –

1min)

8kW 8kW

HVAC3kW

Prop 270kW 700rpm

(100kW@1000rpm –

1min)

protection by fuses

batteries direct on DC bus

(determine voltage level)

DC ON COMMERCIAL SURFACE VESSELS

NOW

7

protection by fuses

batteries via DC chopper

Short-circuit

energy stored in

capacitors

batteries

e-machines

low inductance and resistance

no good standard for calculation

very high & short current (arc flash)

DC PROTECTION

NOW

8

short circuit protection challenging with DC

fuses: less predictable behavior, relative slow

mechanical: large, relative slow, very special made

energy stored in capacitors, batteries and electric machines, while “grid” has low impedance: so

very high short circuits and arc flashes

for high reliable system requires 2-split system

most consumers AC supplied large grid converter

floating DC bus voltage 2x oversized and special converter

LIMITS OF TODAY DC SYSTEMS

NOW

9

AGENDA

10

1. LIMITATION OF CURRENT DC SYSTEMS

2. SMART DC TECHNOLOGY

3. SUBMARINE SMART DC SOLUTIONS

4. TRADE OFF REVIEW

5. CONCLUSIONS

converter rated for voltage difference

(similar to AC autotransformer):

example:

1000Vdc bus

battery voltage: 900…1100V

converter power rating: 10% of battery

power

practical cost saving is lower because

of more complex topology

much higher efficiency

PARTIAL POWER CONVERTER

11

Edison's missing link

large size reduction

high efficiency (larger then normal grid

converter)

by resonance converter using soft-

switching

HIGH-FREQUENCY DC TRANSFORMERS

12

low level droop control

droop line based on device type and priority

secondary control

by configurating connections on

section/zone level

on/off (consumers, sources and prosumers)

based on power availability and priority

balance demand vs production

congestion management

tertiary control

optimize power system for operational

objective (fuel efficiency, performance, ect.)

CONTROL

13

physical layer

2nd layersecondary control

1st layerprimary control

3rd layertertiary control

electrical network: V

engine G

speed contro l

Batterypack

BMSvolt.

contr.

M

Power Management System(PMS)

Propulsion control system

(PCS)

speed contr.

Energy Management System(EMS)

sub-grid

volt contr.

volt contr.

AGENDA

14

1. LIMITATION OF CURRENT DC SYSTEMS

2. SMART DC TECHNOLOGY

3. SUBMARINE SMART DC SOLUTIONS

4. TRADE OFF REVIEW

5. CONCLUSIONS

zonal ring distribution

protection by SiC based SSCB’s

fix bus voltage

connect batteries with (partial rated) converters

primary control by voltage droop

secondary control by priority (on/off, limitation)

realizes

always two supply routes

system size reduction

very low short-circuit currents

PROPOSAL

15

MPM

G ADP

SSC

B

SSC

B

SSCB SSCB

SSCB SSCB

SSC

BSS

CB

zon

e 2

au

xili

ari

es

SSC

BSS

CB

zon

e 1

au

xili

ari

es

SSC

BSS

CB

zon

e 3

au

xili

ari

es

ESS

ESS

G

AIP

SSCB

SSCB

SSC

B

SSC

B

ESS

SSC

BS

SCB

SSC

B

ESS

SSC

B

constrains

all connections should be active:

no large current steps or inrush currents

low voltage drop on cables

non active consumers on separate grid (via

“power gateway”)

PROPOSAL CONT.

16

MPM

G ADP

SSC

B

SSC

B

SSCB SSCB

SSCB SSCB

SSC

BSS

CB

zon

e 2

au

xili

ari

es

SSC

BSS

CB

zon

e 1

au

xili

ari

es

SSC

BSS

CB

zon

e 3

au

xili

ari

es

ESS

ESS

G

AIP

SSCB

SSCB

SSC

B

SSC

B

ESS

SSC

BS

SCB

SSC

B

ESS

SSC

B

AGENDA

17

1. LIMITATION OF CURRENT DC SYSTEMS

2. SMART DC TECHNOLOGY

3. SUBMARINE SMART DC SOLUTIONS

4. TRADE OFF REVIEW

5. CONCLUSIONS

high safety level - low short circuit currents

high availability – zonal ring (always two routes), decentralized power generation and storage

reduction of volume – new semiconductors enabling hf converters, no AC grid, system rating

based on average power level

efficient system

smart - full control and monitoring

WHAT IT BRINGS

18

AGENDA

19

1. LIMITATION OF CURRENT DC SYSTEMS

2. SMART DC TECHNOLOGY

3. SUBMARINE SMART DC SOLUTIONS

4. TRADE OFF REVIEW

5. CONCLUSIONS

Smart DC microgrid technology makes submarines grids:

smaller

safer

more efficient

smart

Not “off-the shelve” available today

However can be realized today

CONCLUSIONS

20

THANK YOU FOR YOUR ATTENTION

QUESTIONS?

21

ASD TUG 2810