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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