1. Modular Multi-Mode Power Supplies for Naval Power Systems
John Herbst, Joe Beno, Hamid Ouroua, Robert Hebner, Scott Pish, Jon Hahne
University of Texas at Austin Center for Electromechanics
ASNE Day 2015
March 3 – 5, Arlington, VA

2. Presentation Overview
Rotating Electric Machines for Naval Applications
Modular Multi-Mode Power Supplies (M3PS)
Combat Hybrid Power Supply (CHPS)
Compensated Pulsed Alternators
Conclusions

3. Rotating Electric Machines for Naval Applications
Rotating electric machines are a critical element of every naval vessel in service today
Rotating electric machines address a broad range of naval applications:
Simple electric motor driven loads
Prime/auxiliary power generation
Emerging high speed generation
Propulsion
Induction, WF synchronous, PM
EMALS pulsed power system
Specialized rotating electric machines are already an important part of the US Navy’s toolbox
Providing robust, reliable solutions for critical mission loads

4. M3PS Concept
Modular system of high performance rotating electric machines combining inertial energy storage with continuous and pulsed power capabilities
Builds on successful EMALS concept
Provide stand-alone solutions or can be integrated into hybrid systems as part of an Energy Magazine
Scalable systems to meet range of applications
Fully integrated topology to maximize energy and power density

5. Flywheel Topologies Non-Integrated Topology
• Larger than other topologies, but
may have most simple assembly
• Maximum use of conventional M/G
systems and technology
• Flexible / adaptive design
• Power generation outside of vacuum
• Requires shaft seal and coupling
Partially-Integrated Topology
• Smaller and more efficient than non-
integrated
• Good use of available M/G technology,
but integration required
• Good design adaptability
• Favors use of PM generator
• Heat generation on rotor requires
careful engineering
Fully-Integrated Topology
• Most compact system
• Special purpose flywheel system
• Favors use of PM generator
• Heat generation on rotor requires
special engineering
• Rotating magnets at large radius
• Uses arbor or magnetic bearings to
match rotor growth

6. Combat Hybrid Power Supply

7. Combat Hybrid Propulsion System (CHPS)
Dual use flywheel energy storage
“Inside-out” arbor-less technology
Continuous duty and pulse loads for offensive and defensive systems
Rotor assembly and material property matching key for life requirements
Demonstrated
Assembly of multi-pole magnetic rotor subassembly
Assembly of full scale, liquid cooled stator
Static torque, voltage, and cooling testing
Full scale magnetic bearing under static load with simulated rotor growth
Combat Hybrid Power Systems (CHPS) Flywheel
5-10 MW (peak), 4.5 MW (cont.), 7 kW-h
CHPS
Component
Verification S S

8. CHPS-A Machine

9. CHPS-A Performance Add composite rings to increase energy storage
Upgrade design for higher peak/continuous power

10. Complete CHPS Flywheel System
Lab Bearing Amplifiers
Flywheel
Rectifier
Assembly
Lab Safety Disconnect
Converter
Transformer

11. CHPS-N Characteristics (evolving)
Multifunction machine
Services multiple loads that require intermittent electric power
UPS
Dark start
Power quality improvement
Small size
Fits through a 26”- diameter hatch
Advanced technologies for performance enhancement
High speed machine technology
Advanced composite banding
Innovative heat transfer techniques
Novel bearings
Shock load mitigation
Advanced materials
Low loss / High temperature

12. Compensated Pulsed Alternators

13. Compensated Pulsed Alternators
Conceived at University of Texas in late ’70s
Original application was laser power supply for Lawrence Livermore inertial confinement fusion program
Wound field synchronous generator with compensating windings or eddy current shields
Low impedance
High airgap flux densities
Gigawatts for milliseconds
Capable of directly driving large pulsed loads
Demonstrated synchronized discharge of parallel machines
Megamp Output
Current Pulses

14. Armature Compensation
Use image currents in compensating winding or conductive eddy current shield to contain magnetic fields from armature output currents
Minimizes internal impedance
Multiple topologies and compensation techniques
Iron core, air core, rotating field, rotating armature, single- or multiphase
Active, passive, selective passive
External excitation or self excitation

15. Compensation Techniques
Active compensation features a compensating winding in series with the armature winding
Sharp pulse with fast rise time
Passive compensation uses a conductive eddy current shield
Essentially sinusoidal output pulse
Selective passive compensation uses a shorted compensating winding rotated azimuthally relative to the main armature winding
Can be tailored for a variety of output pulse shapes

16. PA Development History

17. Latest PA Designs
Latest PA designs are air core machines without compensation
Highest power density
Self-excited system
“Seed” current injected into rotating field winding
Resultant armature output is rectified and fed back onto the field winding
Armature output is switched into load when peak field current is achieved

18. 2004 Internal Design Study

19. Additional PA Benefits
System can be designed to minimize transient loading on ship power system
Take advantage of operation over wide speed range to buffer supply
System stores energy for multiple high energy pulses
Stored energy available to support other transient loads or to provide active filtering

20. Technology Comparison
12 MJ Capacitor Bank
Acknowledge Age of caps
Mention switches on compulsator
Need motor/generator for flywheel
22 MJ
Compulsator
480 MJ
Flywheel

21. Summary/Conclusions
Rotating electric machines are already being used to address critical mission loads for the US Navy
Modular Multi-Mode Power Supplies (M3PS) are a family of advanced rotating machines that can effectively address a wide range of Navy applications
M3PS concepts offer improved energy & power density relative to alternative pulsed power systems
M3PS concepts can also provide additional support for the ship power system when not being used for their primary mission load