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/commutators

2.Significant idling iron loss reduction

3. 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 topology

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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

237

237.5

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238.5

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239.5

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Iron Losses in Synchronous Generator

Field Current (Aac)

Po

wer

Lo

ss (

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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