1

HydroFly: Flywheel

Gavin AboNate StoutNathan Thomas

Background

•The flywheel is a mechanical energy storage device

–Once up to speed very little energy is required to

maintain desired speed

•Small draw on AMPS

Background Continued

• Flywheels were used during the industrial revolution to smooth out

torque pulses in mechanical systems

– We will use it in a similar fashion to smooth out voltage sags on

the AMPS

Voltage Sags• Drop in RMS voltage

– Typically last from 1/2 cycle to a minute

– Caused by actions on the system that have large current draws

• Motors starting

• Transformers energizing

• Pulsed load switching

• Electrical faults

2

Why Sags Are Bad

• Voltage sags have adverse affects on sensitive loads

– Sags can cause loads to shutdown

• Loss of use

• Loss of Data

• Loss of production time

Navy

• Survivability of Naval ships in battle situations

– In battle situations voltage sags can occur due

to various reasons, causing critical systems to

go offline

• Flywheel voltage sag detection devices could be used to help

protect these critical systems

Education

• The flywheel energy storage system may be implemented into future

power classes at the University of Idaho for educational purposes

– Power quality classes

– System protection classes

– Transient analysis classes

Main Objective

• Implement the design by Satish Samineni– Be able to correct for up to 33% voltage sags

on AMPS

3

• We will focus on– Induction motor controller– Programming of the DC link– Synchronizing to AMPS– Protection circuitry

• We will not do:– Design of DC link– Design of Induction motor controller

Block Diagram

Switching PWM• A triangle wave reference is

applied to a signal

– Compared

– Triangle high: logic 0

– Signal high: logic 1

– Applied to all 3 phases

4

Block Diagram Series Transformer Diagram

Flywheel energy

A

CB

storage system

Synchronization & Protection• Use a phase lock loop to monitor and regulate phase• Add any additional protection needed xθ( ) 2sinθ( ):= yθ( ) sinθ( ):= zθ( ) xθ( ) yθ( )+:=

10 5 0 5 104

3

2

1

0

1

2

3

4

xθ( )

yθ( )

zθ( )

θ

In phase Out of phase

a θ( ) xθ 75deg⋅+( ) y θ( )+:=

10 5 0 5 104

3

2

1

0

1

2

3

4

xθ 75deg⋅+( )

y θ( )

a θ( )

θ θ, θ,

5

BudgetFlywheel Budget

Item PriceInduction Motor Controller $350DC link $4,0003-phase transformer (500VA) $125Design Poster/Report Binding* $15Project Display Costs* $35Miscellaneous $300

Total $4,825

*Shared costs between the two groups

Time Schedule

1/31/2005

2/28/2005

3/28/2005

4/25/2005

5/23/2005

6/20/2005

7/18/2005

8/15/2005

9/12/2005

10/10/2005

11/7/2005

12/5/2005

1/2/2006

Initial Design for Prototypes

Project Brief ings (w eekly - Semester 1)

Ordering Voltage Inverters and Buck Converter

Design Review

Interface Components to Fuel Cell

Implement simulation for Flyw heel System

Demonstrate Working Prototype

Project Report and Notebook Due (Semester 1)

Summer Break

Project Brief ings (w eekly - Semester 2)

Interface Fuel Cell Components to AMPS

Interface Components to Flyw heel

Revise Voltage Control System

Interface Flyw heel to AMPS

Finalize Protection Circuitry

Complete/Debug Interfacing to AMPS

Final Product Demonstration/Release/Final Report

Questions?

www.ece.uidaho.edu/hydrofly