Why Diesel Electric Propulsion ?

System alternatives.

Technical features

Why Diesel Electric Propulsion?

IGBT = Insulated Gate Bipolar Transistors

TYPICAL ARGUMENTS:

� Fuel SavingsOffshore: 25 - 40% reduction!

� Reduced maintenance costMore on board maintenance

� SafetyRedundant Propulsion with FP Azimuths

� DesignImproved design due to DEP

What makes diesel-electric propulsion attractive?

Indications that diesel electric propulsion is more favourable :

• Operation modes with low load during longer periods• Large on board electrical load• Dynamic positioning• High demands for low noise and vibrations• High demands for manoeuvrability• High demands for redundancy and availability• Etc.

Choice of propulsion systemfor a vessel

“The hull and propeller type is chosen on basis of the needed hydro-dynamic efficiency”

“The propulsion system is chosen on the basis of the the operational profile (or special demands) to the vessel”

Lips: Shaft and rudder (CP)

Schottel: Hub Azimuth (FP)

FP = Fixed Pitch

CP = Controll. Pitch

Choice of propulsor

Conventional Controllable Pitch Propeller (CPP)� Typical for Diesel mechanical propulsion system

� High ratings� Low cost (?)

Schottel: Tunnel thr.(FP)

Aquamaster: Azimuth (FP)

Contra rotating

Schottel: Azimuth (FP)

Twin Propeller

FP = Fixed Pitch

CP = Controll. Pitch

� Also with Diesel electric Propulsion

� Hybrid Diesel electric Propulsion

Schottel: Tunnel thr.(FP)

Aquamaster: Azimuth (FP)

Contra rotating

Schottel: Azimuth (FP)

Twin Propeller

FP = Fixed Pitch

CP = Controll. Pitch

Choice of propulsor

Azimuth Thruster(s)� Typical for Diesel Electric Propulsion system

� Controllable or fixed pitch

� With or without nozzle

� Contra rotating, Duo propeller

� POD

Reduced Fuel Consumption

Specific Fuel Consumption:

� High load on running dieselsImproved SFC

160,0

170,0

180,0

190,0

200,0

210,0

220,0

230,0

240,0

250,0

260,0

270,0

280,0

290,0

300,0

310,0

320,0

330,0

340,0

350,0

360,0

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

effekt (kW)

Sp

es

ifik

t fo

rbru

k (

g/k

Wh

)

12M32C/600rpm 1xCAT 3508BTA 2xCAT 3508BTA

Reduced Fuel Consumption

Propeller Efficiency:

� Optimum Propeller Efficiency with speed control

Reduced Fuel Consumption

Savings:

Losses:

Typically 10 - 12 % from shaft to shaft.

� Drastically improved propeller efficiency at low load!� Equal or better propeller efficiency at high load!CPP contra FP?

� Improved Specific fuel consumption (?)

Total:

� Typical ROV vessel: 25 - 40% reduction compared to conventional systems!!

� Coast guard vessels ??

Diesel mechanical propulsionTwin screw, CP conventional propellers

Diesel engine

Generator set

Gear with clutch

Generator

Propeller (CP)

Tunnel thruster (CP)

Y/DStarter

Y/DStarter

Diesel electric propulsionTwin screw – FP azimuth thruster

�GPA Generator Power Adaptation

�Power Management (PMA 300)

�Integrated Automasjon

�Thrustercontrol

�Short circuit analysis

•Harmonic analysis

Diesel electric propulsionTypical single line diagram

Diesel engine

Generator

Main Switchboard

Transformer

(12 pulse)

Frequency converter

Propulsion motor

Propeller (FP)

Tunnel thruster (FP)

Hybrid PropulsionAn golden compromise?

HYBRID PROPULSIONSingle screw - System layout

Hybrid PropulsionTwin Screw, CP propellers

HYBRID PROPULSIONTwin Screw - System layout

AzimuthThruster2200 kW

Motor

5300 kW

Stern Thruster883 kW

Shaft Generator

Bow Thruster2200 kW

SternThruster883 kW

Shaft Generator

Motor

5300 kW

Winch

Winch

Vessels suited fordiesel electric propulsion

Offshore vessels

Research vessels

Navy/ Coast guard vessels

MASTERDRIVESWater Cooled Frequency Converter

6 Pulse and 12 Pulse operation

Voltage: Power: Width:690 V 1200 kW 1840 mm

800 kW 1540 mm630 kW 1540 mm

440 V 710 kW 1840 mm630 kW 1540 mm

Additional 300 mm for internal cooling unit

Standard Height 2100 mmDepth 640 mm

The unit is the most compact on the market!

MASTERDRIVESParts of a Frequency Converter

Rectifier

Inverter

Output

Capacitors

Transformer

Generator Power Adaptation System

GPA GPA

GPA GPA GPA GPA

Main Switchboard

Generators

Conv. Transformer

Freq. Converter

Propulsion Motor

Generator Power Adaptation System

GPA

Uf

Next generator

M

G

GPA - The ultra fast dynamic load limtation system.

The system adapts and limits the propulsion power according to the actual available generator capacity.

The GPA is not a part of the PMS (Power Management System)

P

t [ms]

170 ms

Pre-charge Circuit

The pre-charge circuit limits the in-rush current on start-up to a minimum by pre-charging both the convertertransformer and the capacitors.

Pre-Charge Contactor

Pre-Charge Reaktor

Converter Transformer

Frequency Converter

Line Side Rectifier

Inverter on the Motor Side

Propeller Drive Motor

D

y d

Non heavy consumer

...as a Non Heavy Consumer

Frequency Converter Propulsion System...

GPA System (Generator Power Adaptation)- fast acting monitoring and control system

- no more power consumption than available from the highest loaded generator

- no generator is overloaded

- possible to run the propulsion on one small generator

Pre-Charge Circuit

- converter transformer and DC-voltage capacitor bank- via the auxiliary supply.- main circuit breaker can be closed without any in-rush current.

- in-rush free current start-up

Power Consumption Only- takes active power (kW) only from the main supply

(and some excitation current for the converter transformer if present)

Type of Frequency ConverterHarmonic feedback

6-pulse rectifier 12-pulse rectifier Active Front End

6-pulse rectifierCurrent harmonic feedback

Single 6-pulse Diode Rectifier Brigde

Transistor Inverter Brigde(IGBT - Insulated Gate Bipolar Transistors)

12-pulse RectifierCurrent harmonic feedback

Double 6-pulse Diode Rectifier Brigde

Transistor Inverter Brigde(IGBT - Insulated Gate Bipolar Transistors)

Active Front EndCurrent harmonic feedback

Transistor Rectifier Brigde

Transistor Inverter Brigde(IGBT - Insulated Gate Bipolar Transistors)

”Back to Back”

Quasi 24-pulse rectifierCurrent harmonic feedback

Optimal when:

+30°

12-pulse -7,5° +7,5°

+30°

12-pulse

24-pulse

Pload= 50% Pload= 50%

Additional phaseshift betweentransformersgive 24-pulse feedback

Harmonic Voltage LevelTypical Calculated Values

0 %

2 %

4 %

6 %

8 %

10 %

12 %

14 %

5 7 11 13 17 19 23 25

6-pulse

12-pulse

AFE

Harm

onic

Voltage

Level

Harmonic Order

System solutionHarmonic feedback

Typical THD:

•6-pulse: 16+%

•12-pulse: 7-8%

•q24-pulse: 3-5%

•q36-pulse: low

For FurtherImprovement:

•230 / 450V Filters