Flywheel Storage for Lunar Colonization

Flywheel Storage for Lunar Colonization

University of Idaho Department of Electrical and Computer Engineering

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Purpose Statement

To establish the scientific and technical merit, and feasibility, of using flywheel energy storage systems in support of human colonization and exploration of the lunar surface

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Flywheel Storage for Lunar Colonization

• Machine Topology Evaluation• Power Electronics and Control• Construction of Test Apparatus

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Flywheel Storage for Lunar Colonization

Machine Topology EvaluationIan Higginson

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Research Objectives• Evaluate technical merit and feasibility

of:

Electrical energy transfer machinery that minimizes iron idling losses

Extreme temperature electronics to manage energy transfer and storage

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1. No slip rings/commutators2. Significant idling iron loss reduction3. Low volume

High torque per volume High torque per mass

Flywheel Criteria

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• Synchronous Reluctance• Field Regulated Reluctance• Iron-on-rotor PM;

Ironless statorIron rotor

• Ironless PM (Halbach array)

Machine Topologies

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Torque per Unit Volume• Synchronous Reluctance: 34.16

kNm/m3

• Field Regulated: 35.52 kNm/m3

• Iron-on-rotor PM: 27.18 kNm/m3

• Ironless PM: 25.33 kNm/m3

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• Prepare Phase 2 Proposal• Formalize force density equations• Verify analytical data• Prototype low idle iron loss machine• Develop equations for torque per unit

mass

Goals

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Power Electronics for Lunar Flywheels

Power Electronics and ControlChristopher Douglas

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Research Objectives• Evaluate technical merit and

feasibility of:

Electrical energy transfer machinery that minimizes iron idling losses

Extreme temperature electronics to manage energy transfer and storage

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• Operate over extreme temperature range

• Reduce excess mass• Increase energy/power density• Develop control method for flywheel

Purposes

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• Extreme thermal & radiation environment Phase I involves thermal problems -190C to +125C 336 hours of Lunar night/day Radiation exposure

• Heat transfer mechanisms Conduction Radiation

Lunar Environment

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Semiconductor Technologies• Silicon on Insulator

Commercial Ratings HTANFET• 90V, 1A• Rated -55C to +225C

Cycle Testing -195C to +85C• Silicon Germanium HBT – Research

Data 50V, 2A Cycle Testing -195C to 25C Cycle Testing 25C to 300C 14

Application

• Heated or cooled enclosure Added mass Lost energy

• Temperature division multiplexing (TDM) Range dependent

electronics Strategic layout of

electronics• Stacked MOSFET

topology15

Deflux Control

• Rotor defluxing method Decaying sinusoidal current (θr)

• Parameters Decay rates Frequency of defluxing current

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Defluxing - Stator

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Future Goals• Prepare phase II proposal• Acquire models for power

electronics• Develop control system for lab

prototype• Deflux spinning rotor• Investigate:

Temperature division multiplexingStacked MOSFET topologyHeat transfer in vacuum

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The University of Idaho

Construction of Test ApparatusTimothy Hildebrandt, Bryan Hyde,

Josh Ulrich, Kord Hubbard

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Synchronous Reluctance Machine• Purchase Machine

High Quality Bearings Controlled Environment

• Characterize Losses Low Friction Machine

• Power Electronics Lunar Environment Adaptability to Machine

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Power Loss Characterization• Present:

Armature resistance Brush drop losses Interpole winding resistance

• Future: Iron losses• Difficult to measure

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Preliminary Iron Losses• Constant Speed• Vary Gen. Field Current

0 1.667 3.333 5 6.667 8.333 10236

236.5

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237.5

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238.5

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239.5

240Iron Losses in Synchronous Generator

Field Current (Aac)

Pow

er L

oss (

W)

PFEloss

IfAC

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Power Inverter • Used for defluxing

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Future Goals• Prepare for Phase II Proposal• Purchase/Characterize machine• Develop testing strategy• Measure iron losses accurately• Define lunar power requirements

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• April – Sep.: Prepare Phase 2 Proposal• April 30th: Formalize force density equations• May 1st: Begin verification of analytical data• May 15th: Parameterize defluxing method• May – Aug: Investigate TDM scheme• June 1st: Construct flywheel prototype

2010 Timeline for Future Work

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• June: Construct prototype electronics system

• June – July: Develop testing strategies• June – Aug: Collect data at Boeing• June – Aug: Characterize machine• June – Sept: Investigate switch device

models• June – Aug: Develop torque per mass

eq’s.

2010 Timeline for Future Work

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2010 Timeline for Future Work

• Aug: Prepare testing environment• Aug: Design of power electronic

system• Aug – Sept: Document results• Sept: Submit Phase 2 Proposal• Sept: Measure losses accurately

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The University of Idaho

Discussion

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