hybrid electric drive evaluation for cg 47 class guided missile cruisers

Hybrid Electric Drive Evaluation forCG 47 Class Guided Missile Cruisers& Dwight Alexander, David Rummler, Aydin Mohtashamian, George Robinson, Mohamad Zahzah,

Christopher T. Farr, and Gregory E. Poole

AbstractThe hybrid electric drive (HED) topology has been studied and reported on for application to the

DDG 51 class guided missile destroyers. The Navy tasked an industry team comprised of Northrop

Grumman and L-3 Power Paragon to complete a sizing and concept study to apply the HED conceptto the CG 47 class guided missile cruisers. This paper reports on the results of this study, including

system architecture and sizing, impact on fuel use and emissions and technical hurdles. Additionally,

key component developments are reported, including an electric machine topology and sizing study

completed by Curtiss Wright Electro-Mechanical Division.

IntroductionNumerous studies have been reported defining

and assessing a hybrid electric drive (HED)

modification to the existing DDG 51 propulsion

and power generation plant (Doyle and Clayton

2006; McCoy et al. 2007; Castles and Bendre

2009). The principal motivation is reducing fuel

consumption. The Navy tasked an industry team

comprised of Northrop Grumman and L-3

Power Paragon to examine the merits of these

HED concepts applied to the CG 47 class guided

missile cruisers. As shown in Figure 1, the HED

topology considered interconnects the present

mechanical drive propulsion system to the ship’s

service electrical power system. Similar to a

DDG 51, the CG 47 class engineering plant is

comprised of four LM2500 propulsion

turbines (two per shaft) and three Alison

(now Rolls-Royce) gas turbine generator

(GTG) sets.

The interconnection is achieved by attaching a

suitably sized electric machine (electric rotating

machine [ERM]) to the propulsion train and

connecting the electric machine to the ship’s

service power bus via a bidirectional power con-

verter. This topology allows propelling the ship

using ship’s service power and generating ship’s

service power derived from the propulsion tur-

bines. This interconnection allows securing

propulsion turbines at ship’s low speeds (o15

knots) in an electric propulsion mode and secur-

ing one of the two normally operating GTGs

when not in electric propulsion mode. This

optimizes utilization of the available propulsion

turbines and ensures they operate at a better fuel

consumption point. Two basic topologies exist

to tie the ship’s propulsion and power generation

systems together. The first couples the ERM to

the ship’s propulsion shaft, either directly or via

a dedicated gear. The second couples the ERM

into the existing main reduction gear (MRG)

that transforms the high-speed propulsion tur-

bine output to the desired low-speed propulsion

shaft requirements. Our study focused on the

latter topology, which was assessed as being an

easier retrofit.

The HED system can be designed to operate in

two distinct modes:

T E C H N I C A L P A P E R

& 2010, American Society of Naval Engineers

DOI: 10.1111/j.1559-3584.2010.00269.x

2010 #2 &67

&Propulsion—ship’s electric power is used to

propel the ship via an electric motor coupled

in to the existing ship’s drive train. This mode

requires an electric motor and associated

motor drive.

&Power generation—ship’s electrical power is

generated by the ERM mechanically driven by

the existing ship’s propulsion train. This

system requires the electric motor operate as a

generator and a power converter to synthesize

the ship’s 450 V, 60 Hz, three-phase power.

To operate in both modes requires the power

converter be ‘‘bidirectional,’’ functioning as both

a variable frequency drive and constant voltage,

constant frequency inverter.

HEDSystemSizingTwo fundamental constraints limit the HED

system rating: (1) available electric power to

support propulsion mode and (2) physical space

constraints within the existing ship’s engineering

spaces.

For this study, we assumed the ship’s electrical

power demand to be the 24-hour average load,

defined by the Navy as approximately 2,600 kW.

There are three 2,500 kW GTGs installed and

standard operating criteria assumes only two

GTGs are available. The total power generation

capacity is, then, 5,000 kW. Limiting the GTG

loading to 90% rated output leaves 4,500 kW

available for power generation. Removing the

24-hour average ship’s load results in 1,900 kW

total power available for ship’s propulsion.

Figure 2 illustrates the ship’s speed versus total

propulsion power at 15 knots and lower. As can

be seen, 1,900 kW equates to a ship’s speed

slightly over 9 knots.

However, though available electric power limits

the HED size to around 1,900 kW (950 kW per

shaft), there is one additional consideration. In

addition to saving fuel by securing the LM2500

propulsion turbines at low ship’s speeds, fuel

savings can be achieved at higher ship’s speeds

by using power generated by the HED system to

PowerConverter

MainReduc-

tionGear

LM2500Gas Turbine Module


Electric Motor/Generator

New

Modified

GasTurbineModule

GeneratorGas

TurbineModule

Generator

GasTurbineModule

Generator

Ship’sLoads

MainReduc-

tionGear



PowerConverter

PropulsionPower Generation

Figure 1: HybridElectric Drive Inter-connects MechanicalPropulsion withElectrical PowerGeneration

NAVAL ENGINEERS JOURNAL68 & 2010 #2

Hybrid Electric Drive Evaluation for CG 47 Guided Missile Cruisers

secure one of the two GTG sets. To allow this

mode, the HED system must generate the equiv-

alent power of a single GTG, approximately

2,500 kW (1,250 per shaft). Finally, the Navy

desired to maintain commonality with a DDG

51 solution whose GTGs are rated at 3,000 kW.

Therefore, we decided on an HED system

size of approximately 3,000 kW (1,500 kW

per shaft).

Fuel Savings andEmissionsReductionsBased on the limitation to operate the system in

propulsion mode at 9 knots and below and using

the HED system in power generation mode at 10

knots and above, fuel consumption could be

calculated given the typical annual ship’s steam-

ing profile and propulsion plant operating

configurations. Figure 3 shows the annual oper-

ating profile for the CG 47 class. The ship spends

approximately 35% of its annual operating

hours at 9 knots or less.

The Navy provided data defining the propul-

sion plant-operating mode as a percentage oper-

ating time at the defined speed points. The

propulsion plant is operated in three distinct

configurations:

&Four engine (4E)—all four LM2500 propul-

sion turbines (PT) on line. This mode is used

for both high ship’s speeds and for certain

operating scenarios where having all four PTs

on line is prudent.

&Two engine (2E)—one PT per shaft is on line.

&Trail shaft (TS)—one PTon line with the other

shaft in ‘‘trail’’ (‘‘free-wheeling’’). This is a fuel

economy configuration.

We made a number of assumptions on operating

modes using an HED system:

&No changes in percentage of annual operating

hours the propulsion plant is in 4E configura-

tion.

&Hybrid operation replaces TS mode.

&Electric plant ship’s service loads are constant

at the 24-hour value, which limits hybrid pro-

pulsion at 9 knots and less.

Using these assumptions and supplied data, an-

nual fuel consumption was calculated and

compared with the baseline annual fuel

consumption (Figure 4).

These results show an annual fuel consumption

reduction from approximately 88,000 barrels to

about 67,000 barrels. This equates to a 24% re-

duction leading to a US$3.3M savings based on

the Navy-supplied burdened fuel cost of $153/

barrel. If the system is not sized large enough to

allow securing an operating GTG, then the fuel

savings are reduced considerably. An annual

savings of only 11,000 barrels (US$1.6M) is

achieved operating the system only in propulsion

mode only below 10 knots.

A side effect of reduced fuel consumption is a

reduction of gas turbine engine emissions. Table

1 summarizes the propulsion turbine emissions

reductions. The incremental increase in GTG

turbine emissions was not characterized because

this information was not available.

Propulsion InterfaceBased on previous studies and a ship check, we

focused on interfacing the HED electric machine

with the existing MRG. This gear is a typical

double-helical, locked train, articulated double

reduction gear assembly, as shown in Figure 5.

Figure 2: CG 47Propulsion PowerRequirements at LowShip’s Speeds

NAVAL ENGINEERS JOURNAL 2010 #2 &69

Three basic connection configurations were

explored:

&Variant 1 (high-speed shaft)—ERM would

rotate at the same speed as the propulsion

turbine (�1,200–3,600 rpm).

&Variant 2 (intermediate shaft)—ERM rotates

at the speed following the first reduction

(�500–1,500 rpm).

&Variant 3 (power take off [PTO] gear)—an

additional gear is attached to the MRG, which

increases the speed allowing a higher speed

ERM. We chose a PTO providing a speed

range of �2,700–8,000 rpm.

Because the ERM size is inversely proportional

to operating speed, the highest speed connection

is preferred, subject to other limitations. The

high-speed shaft connection was dismissed due

to the complexity of MRG modifications re-

quired to allow declutching the ERM from the

PT. Both the intermediate shaft and PTO con-

nections are considered viable. Further studies

are required to make a down select.

Based on existing engineering plant space con-

straints, the available envelope for the ERM was

determined as:

&High-speed and intermediate shaft ‘‘Direct

Connect’’—the ERM is axially aligned with

the respective MRG shafting. There is a

bulkhead approximately 7 ft either aft

(STBD) or forward (PORT) of the MRG

casing. For intermediate shaft connection,

approximately 77 in. is available; the high-

speed shaft connect allows approximately

110 in.

-

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

8 9 10 11 13 15 17 19 21 FP

Fu

el C

on

sum

pti

on

(BB

L p

er Y

ear)

Ship's Speed (knots)

CG 47 Annual Fuel UseHED Propulsion + PDSS

Standard CG 47

HED Prop + PDSS Mode

Figure 4: CG 47 Annual Fuel Consumption

Figure 3: CG 47 Typical Annual Speed/Time Profile

NAVAL ENGINEERS JOURNAL70& 2010 #2


&PTO ‘‘Offset’’ connection—approximately

110 in. is available. This configuration

allows placing the ERM offset from the axial

line of either the high-speed or intermediate

shafts.

All configurations had an approximately 75 in.

diameter limitation.

Power ConverterThe HED power electronics converter provides

the electrical interface between the ship’s service

60 Hz distribution bus and the propulsion

connected motor/generator. Figure 6 illustrates

the basic power converter topology and power

flow. The HED power converter supports the

two main modes:

&propulsion with power flows 1A and 1B,

&power generation with power flows 2B and

2A.

Two HED system operating modes require four

Power Converter operating modes working in

conjunction with the ship’s Machinery Control

System (MCS):

&1. Sub-mode 1A—pull 60 Hz ship’s service

power and rectify to DC

&draw real and reactive power as allowed by

the MCS,

&operate in power factor mode to minimized

line currents if MCS directed,

& rectify 60-Hz ship’s service power while

meeting MIL-STD-1399 power quality for

reflected harmonics,

& regulate internal converter DC bus to

specified value,

& safely disconnect from the ship’s service bus

for any internal converter faults.

&2. Sub-mode 1B—invert DC bus and drive

motor at required speed and power

& generate variable frequency and voltage

output waveform to control HED motor

as directed by MCS,

&produce motor waveform quality to meet

allowable vibrations into the shaft,

&provide seamless pickup and release of

HED motor,

&provide torque-limiting control to prevent

shaft or reduction gear damage.

&3. Sub-mode 2A—provide 60 Hz power to

ship’s service bus

& generate 450 V, 60 Hz ship’s service power

meeting MIL-STD-1399 Section 300A

requirements,

&provide real and reactive power as directed

by MCS,

TABLE 1: Propulsion Turbine Emissions

CG 47 Emissions

Total NOx

(tons/year)

Total CO

(tons/year)

THC

(tons/year)

Total CO2

(tons/year)

Without hybrid 67 140 10 25,342With hybrid 59 92 6 20,988Reduction 8 48 4 4,354

12% 34% 40% 17%

ShaftOutput

PT InputHigh Speed

Shaft

IntermediateShaft

Figure 5: TypicalMain Reduction GearConfiguration


& emulate GTG interface performance (over-

load and droop performance),

& go online and offline as directed by MCS

and synchronize to energized 60 Hz bus as

directed,

& provide fault current to enable shipboard

circuit breaker coordination,

& safely disconnect from the ship service bus

for any internal converter faults.

&4. Sub-mode 2B—rectify variable frequency

generator output and deliver DC power to

output inverter

& pull power from the propulsion system as

requested by the MCS,

& rectify the variable frequency generator

output and regulate the internal DC bus,

& provide seamless pickup and release of the

HED generator,

& provide torque-limiting control to prevent

shaft or gearbox damage.

The bidirectional power converter mechanical

packaging concept is shown in Figure 7 and

includes all the modular power modules and

required filters and controls. Other key features

and characteristics of the HED power

converter:

& two back-to-back connected bidirectional

inverter modules;

& ability to interface with any motor technology

(induction, permanent magnet, wound-field

synchronous);

& IGBT-based inverter modules use PWM to

convert AC power to DC power and DC to

AC;

& integral filters and algorithms to meet power

quality and noise requirements;

&modular design allowing power module par-

alleling covering 750–3,000 kW power range;

&modular power module design enables low-

cost development and easy maintenance, low

life cycle and reduced costs;

& each inverter module provides built in control,

communication to MCS or other systems,

startup/shutdown, and protection functions;

& control and operation of associated mechani-

cal clutch and circuit breaker supervision;

& circulating water cooling to remove waste

heat.

HEDElectricMachineA study was conducted to examine alternatives

for the ERM that could be used to suit the de-

fined HED connection variants. As previously

described, three connection variants were

defined that have different speed and torque in-

terfaces with the MRG. In addition to speed, the

three variants have differing envelope restric-

tions, which are driven by the location of the

ERM relative to the MRG. Table 2 provides a

list of the key requirements that drive the ERM

design.

Rotational speed range and envelope limitations

are key drivers in selecting pole numbers for the

machines. Envelopes with larger diameter to

length (D/L) aspect ratios can accommodate

slower speed high pole count machines while

high-speed low pole count machines are more

suited to envelopes with smaller D/L ratios.

The combination of speed and number of poles

defines the power converter operating frequency

InverterModule

InverterModule

Bi-Directional Power Converter

DC

Bus1B 2B 1A 2A

450 V60 Hz

VariableFrequency/

Voltage

M/G

ElectricMachine

Ship’sPower

Figure 6: Hybrid Electric Drive PowerConverter Block Diagram and InterconnectSchematic

NAVAL ENGINEERS JOURNAL72 &2010 #2


in both motoring and generating mode. For this

study, an upper bound of approximately 400 Hz

was imposed to maintain stator core losses to

manageable levels while at full speed in generat-

ing mode. Thus, the resulting maximum pole

numbers for each variant can be established

from equation (1) as 12, 32, and 6 for variants

1 through 3 respectfully.

P ¼ 120f

Nð1Þ

where f is the frequency and N is speed.

Selecting pole numbers is also driven by the

technology being considered. In general, the

desire to reduce machine weight and outer di-

ameter pushes the designs toward high pole

counts. However, this is not desirable for induc-

tion machines (IMs) as larger pole counts result

in reduced power factor performance. Other

technologies such as round rotor, wound field

(WF) machines require lower pole counts to al-

low for adequate peripheral spacing for rotor

winding slots. Table 3 summarizes the machine

technologies considered for each variant and the

pole count selected.

The motor candidates considered included (1)

AC synchronous machines WF and permanent

magnet (PM) and (2) AC asynchronous IMs.

Both radial and embedded PM machines were

considered and both salient and round rotor

machines were considered in the

WF category.

PM MACHINES

PM machines offer benefits including increased

efficiency (no rotor ohmic losses), near unity

power factor operation, and no external rotor

excitation. However, PM machine output volt-

age varies linearly with rotational speed.

Therefore, the power converter must manage

the 3 to 1 speed/voltage range while in generat-

ing mode. An alternative operating scenario

is to inject demagnetizing current to force con-

stant terminal voltage over the speed range.

This mode of operation will decrease machine

efficiency and may result in an increase in

machine size or drive magnet material

selection.

PM machines generate open-circuit voltage and

stator core losses when rotating and nonener-

gized. A clutch must be incorporated to

mechanically isolate the machine from the sys-

tem to avoid these losses and to eliminate the

flow of stator current in the event of an internal

fault.

WF MACHINES

WF machines are a robust, well-proven technol-

ogy. The WF machine allows for performance

optimization across the load and speed range via

adjustable field control. However, the WF re-

quires excitation power supplied by either an

integral rotating exciter or static exciter power

supply with slip rings and brushes. Both excita-

Figure 7: Concep-tual Hybrid ElectricDrive Power Con-verter MechanicalPackage

TABLE 2: Electric Machine Requirements

Speed Range Variant 1 1,200–3,600 rpmVariant 2 500–1,500 rpmVariant 3 2,700–8,000 rpm

Power 1,500 kW (over speed range)Voltage 450 VAC (constant, if possible)Maximum diameter 75 in.Maximum length Variant 1 110 in.

Variant 2 77 in.Variant 3 110 in.


tion options increase overall system footprint

and complexity. The round rotor WF machines

typically have a larger diameter than a PM or IM

due to their low pole counts. Power factors can

approach unity throughout the load and speed

range by controlling the rotor field excitation.

IMs

Similar to WF machines, the IM is a well-proven

and robust technology. Simple rotor construc-

tion results in the lowest risk technology

available. The IM, however, will operate at

lower power factors than either the PM and WF

alternatives, because field excitation is provided

as additional stator current from the power con-

verter. This additional stator current and the

rotor ohmic losses results in lower efficiency

compared with the other topologies. The induc-

tion motor has a distinct advantage, however,

due to the capability to line start from ship’s

service power in a casualty mode (bypass the

power converter).

MACHINE DIMENSIONS AND WEIGHTS

In general, all machines considered make use of

radially ventilated air-cooling technology. This is

a simple and well-proven cooling approach that

offers low technical risk and good power density.

In most cases the machine dimensions fall within

the envelope requirements as given in Table 2. If

required, stator water cooling can be imple-

mented to either reduce the machine size or

increase the power capacity within the existing

envelope. Figure 8 shows a cross-section of the

induction motor concept developed for Variant

2 conditions.

Table 4 reports on the dimensions and weights

for each of the concepts defined in Table 3. As

can be seen, the higher speed variants are

generally lighter due to the reduced torque

requirements. Comparing topologies within

variant categories shows the lightest machines

are PM followed by induction. WF machine

weights are the greatest due to low pole

counts (large radial builds) and the need for an

exciter. IMs are heavier than PM machines

primarily due to the lower pole counts

necessary to maintain acceptable power

factor performance.

The dimension that falls closest to the envelope

restriction is the length of the Variant 2 concepts.

As can be seen in Figure 8, the concepts include

an integral clutch and quill shaft. The quill shaft

minimizes the shaft length required to include

TABLE 3: Motor Generator Topologies Considered

Variant

Wound Field (WF) Permanent Magnet (PM) Induction

Salient Pole Round Rotor Surface Embedded Squirrel Cage

1 6 Pole 8 Pole Note 3 12 Pole 6 Pole2 10 Pole Note 2 Note 4 24 Pole 12 Pole3 Note 1 6 Pole 6 Pole Note 1 4 Pole

Notes:1. Surface speeds too high for practical application of this topology.2. High pole count of Variant 2 not optimal for space needs of round rotor field winding arrangement.3. Surface PM requires banding at Variant 1 and Variant 3 speeds.4. Surface PM considered less power dense than embedded design.

Figure 8: InductionMachine Concept forVariant 2

NAVAL ENGINEERS JOURNAL74 &2010 #2


the necessary isolation from the MRG over an

in-line approach.

MACHINE COST COMPARISON

Table 5 provides a comparison of normalized

rough-order-of-magnitude (ROM) cost of the

various machine designs. The costs were esti-

mated using actual material and labor costs of

similar naval hardware components. Costs were

scaled based on differences in size, quantity, and

estimated manufacturing effort. All portions of

the electric machine are included in the cost for

comparison including any unique auxiliary

equipment. For example, the air-to-water heat

exchanger cost is included in all machine costs.

Additionally, the cost of the voltage regulator is

included in the WF machine costs for an equita-

ble comparison. The costs have been normalized

to the lowest cost machine to facilitate this com-

parison.

In reviewing the normalized ROM costs in Table

5, the following observations should be noted:

&The Variant 3, IM was the lowest cost because

it was the simplest technology and the smallest

of all the machines. Therefore, the material

and manufacturing costs were the lowest.

&The WF machines are the most

expensive because of the increased machine

complexity, higher material costs, and higher

manufacturing costs.

The PM machines for Variant 1 and Variant 2

are competitive in price with the corresponding

IM. The higher material cost of the permanent

magnets and the increased manufacturing

costs associated with magnet handling and

installation are offset by the smaller size

of the machine. The smaller size results in

lower costs for the remainder of the machine

components.

SummaryThis paper reported on a Navy sponsored

feasibility and benefit study to examine incor-

porating an HED on the CG 47 class of guided

missile surface combatants. Fuel savings equal-

ing approximately 24% appear achievable,

which equates to an annual savings of US$3.3M

per ship based on a burdened fuel cost of

US$153/barrel. To obtain the maximum fuel

TABLE 4: Motor Dimensions and Weights

Variant

Wound Field (WF) Permanent Magnet (PM) Induction

Salient Pole Round Rotor Surface Embedded Squirrel Cage

1 L 5 74 in. L 5 94 in. L 5 46 in. L 5 61 in.H 5 60 in. H 5 91 in. H 5 56 in. H 5 55 in.W 5 56 in. W 5 69 in. W 5 52 in. W 5 51 in.

Wt 5 16k lbs Wt 5 26k lbs Wt 5 11k lbs Wt 5 16k lbs2 L 5 84 in. L 5 77 in. L 5 78 in.

H 5 80 in. H 5 65 in. H 5 79 in.W 5 76 in. W 5 61 in. W 5 75 in.

Wt 5 25k lbs Wt 5 15k lbs Wt 5 21k lbs3 L 5 93 in. L 5 50 in. L 5 65 in.

H 5 76 in. H 5 47 in. H 5 44 in.W 5 54 in. W 5 43 in. W 5 40 in.

Wt 5 18k lbs Wt 5 10k lbs Wt 5 12k lbs

TABLE 5: Summary of Machine ROM Costs (Normalized)

Variant

Wound Field (WF) Permanent Magnet (PM)

InductionSalient Pole Round Rotor Embedded

1 1.31 1.57 1.09 1.122 1.58 N/A 1.23 1.313 N/A 1.40 N/A 1.00


savings benefit, the systems needs to be bidirec-

tional—allowing both propulsion and power

generation modes. The HED system must be

sized at approximately 1.5 MW per shaft, which

allows securing one of the two operating GTGs

in the power generation mode. A modular, bidi-

rectional power converter is recommended

based on two back-to-back inverter modules.

A power converter module rated at approxi-

mately 800 kW is suggested, with multiple

power converters paralleled to obtain the

final power rating. The electric machine study

indicates both the PM and IM are viable

candidates based on cost, size, and weight. If

feasible, an IM provides the lowest cost alterna-

tive without the drawbacks of a fixed-field PM

machine. However, the hybrid drive solution is

technically viable with either electric machine

technology.

ReferencesCastles, G. and A. Bendre, ‘‘Economic benefits of hybrid

drive propulsion for naval ships.’’ IEEE Electric Ship

Technologies Symposium, April 20–22, 2009, Baltimore,

MD.

Doyle, T. and D. Clayton, ‘‘Propulsion cross-connect on

DDG-51,’’ ASNE Advanced Naval Propulsion Sympo-

sium, October 2006, Arlington, VA.

McCoy, T., J. Zgliczynski, N.W. Johanson, F.A. Puhn, and

T.W. Martin ‘‘Hybrid electric drive for DDG-51 class

destroyers.’’ ANSE 2007 Symposium, ‘‘Fuel Tank to Tar-

get: Building the Electric Fighting Ship,’’ June 25–26,

2007, Arlington, VA.

AuthorBiographiesCDR Dwight Alexander, USN (ret), PE, cur-

rently works for Northrop Grumman Marine

Systems located in Sunnyvale, California and is

the Program Manager for Advanced Electrical

Power System Development. In this capacity, he

has overseen numerous development programs

including hybrid electric drive and high tem-

perature superconducting motors and

generators. Prior to Northrop Grumman, CDR

Alexander served 27 years in the US Navy in

both the enlisted and officer ranks, retiring in

1999. He was an engineering duty officer quali-

fied in submarines with assignments including

tours at Naval Shipyards, Naval Sea Systems

Command, and numerous at-sea billets. He

holds a BSEE degree from the University of

Texas at Austin, MSEE and Professional Degree

of Electrical Engineer from the Naval Postgrad-

uate School. He is a registered professional

engineer in California and Texas and currently

resides outside of Houston, Texas.

Mr. David Rummler currently works for North-

rop Grumman Marine Systems and is based in

Arlington, Virginia. He is the Systems Engineer

Manager for Advanced Launcher Development

Program. He received a MSSE, Systems

Engineering & Analysis, from the Naval Post-

graduate School (NPS). Mr. Rummler was one of

the first two civilians to graduate from NPS’s

Systems Engineering and Analysis Program. He

was also awarded an MIT PD-21 certificate

based on MIT’s System Design and Management

Program. Mr. Rummler attended Northeastern

University, obtaining a BSME and is currently

completing a MSME focused on robotics-

mechatronics at Santa Clara University.

Mr. Rummler has served as a systems engineer in

propulsion and power generation development,

including CG(X)/DD(X) IPS architecture trade

studies and analysis, LHD-8 machinery plant

integration, JMAC/SSC hovercraft concepts, and

technology development programs for submar-

ine and carrier advanced naval propulsion and

power generation systems. His prior experience

included marine systems engineer/program

manager for the US Navy DDG 51 Aegis Class

Destroyer program.

Mr. Aydin Mohtashamian is currently a Program

Manager at L3 Power Systems Group (PSG)

located in Anaheim, California. At L3, Mr.

Mohtashamian has led PSG’s Medium Voltage

Power Conversion and Hybrid Electric Drive

development programs. Before joining PSG, Mr.

Mohtashamian worked for Worley Parsons as a

project engineer, managing various power dis-

tribution and other oil and gas projects. Mr.

Mohtashamian completed over eight years in the

US Army, leaving as a captain. While developing

his skills in program management, he earned a

NAVAL ENGINEERS JOURNAL76& 2010 #2


number of military honors including the Legion

of Merit, Bronze Star, Meritorious Service Me-

dal, and Army Commendation Medal. Mr.

Mohtashamian recently completed his Project

Management Professional (PMP) certification

and received a Project Management Certificate

from the University of California, Los Angeles.

A Lean Six Sigma Black Belt, he holds a

Bachelor of Science degree in nuclear engineer-

ing from West Point and a Master’s Degree in

systems engineering management from Texas

A&M University.

Mr. George Robinson, PE, is a principal project

engineer with L3 Power Systems Group (PSG),

responsible for coordinating and developing

special-purpose motor drives and power con-

verters. Currently, he is developing medium

voltage power converters and power control

concepts to support the NGIPS roadmap. He is

active in developing standards for shipboard

power electronics and has participated on In-

stitute of Electrical and Electronic Engineers

(IEEE) P1662 and P1709 medium voltage

standards working groups. He started his en-

gineering career with General Dynamics

designing and testing autopilot and inertial

guidance systems with strapped down acceler-

ometers and gyros for Standard Missile and

other various US Navy missile programs. Mr.

Robinson is a senior member of IEEE and

earned a Bachelor of Science degree in electrical

engineering from the University of Utah and a

Master of Business Administration degree from

California State University at Fullerton. He is

also a registered Professional Engineer in

California.

Mr. Mohammad Zahzah is a Business Develop-

ment Manager with L3 Power Systems Group

(PSG). In addition to 12 years of teaching

experience in the Electrical Engineering Depart-

ment of California State University at Long

Beach, Mr. Zahzah, as a Program Manager,

designed and developed analog and digital servo

control systems (PID) for magnetically levitated

bearings and motion control systems for speeds

up to 95,000 RPM. Mr. Zahzah, as a Project

Lead/Team Leader, led the effort to design the

control system on the C-17 air cargo transport.

He designed and developed analog and digital

servo control systems (PID) for magnetically

levitated bearings and motion control systems

for speeds up to 95,000 RPM. He designed servo

control block diagrams and system models.

Mr. Zahzah holds a B.S. and an M.S. in

Electrical Engineering (Control Systems) from

California State University at Long Beach, and

has completed his Ph.D. coursework at the

University of California at Irvine (UCI).

Mr Zahzah has published two textbooks and

eight technical papers.

Mr. Christopher T. Farr is presently the Manager

of Electrical Engineering at Curtiss-Wright

EMD. He is responsible for the electrical design

of motors and generators for both commercial

and military applications.

Mr. Gregory E. Poole is presently Senior

Mechanical Engineer at Curtiss-Wright EMD,

a position he has held since 2000. Prior to

joining Curtiss-Wright EMD, he served as a

Navy Nuclear Engineer submarine officer in

the US Navy.


hybrid electric drive evaluation for cg 47 class guided missile cruisers

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