Wave EnergyConversion

Team: Andrew CameronBrent MacLeanHelen McDonaldSteve McDonaldNicholas Smith

Supervisors: Dr. Robert BauerDr. Larry Hughes

Richard RachalsSponsor:

The Project

Objective• To design and build a working scaled model of a 100W

wave energy converter.

Design Requirements• Scalability• Serviceability• Simplicity• Mean power output of at least 100W• Cost less than $1,000.00• Resilient to adverse weather conditions

The Design

Dynamic Buoy

Stationary Shaft(stator) Linear Generator

and Alignment System are housed within the buoy.

Removable TopCap

Presentation Outline

• Construction of Reciprocating Inducting Point Absorber (RIPA)

• Shape Testing• Design and Testing of Linear Generator• Mathematical Model• Concluding Remarks

Construction

RIPA - Construction

Design• Prototype• Proof of Concept• Main

Components• Shaft• Pod• Buoy

Shaft

PodBuoy

RIPA - Construction

Construction Characteristics• Inexpensive• Low or non-corrosive materials• Non-magnetic materials• Simplistic (University Resources)

Primary Element• Linear Generator: Coils & Magnets

RIPA - Construction

Shaft Assembly• Linear Generator Stator• Support Shaft

Upper SupportShaft

LinearGeneratorStator

Lower Support Shaft

RIPA - Construction

Linear Generator Stator• Stainless Steel Shaft• 510 turns of 30 AWG Magnet Wire per coil• Epoxy coated

RIPA – Construction

Pod Components

Magnet Sleeve Assembly Alignment System

AlignmentSupportRing

YokeAssemblies

RIPA - Construction

Pod Assembly

Threaded Rods

Set Screws

RIPA - Construction

Buoy Assembly

Buoy Internal Structure

Upper Core

LowerCore

Top Cap

RubberFoam

RIPA - Construction Overall Assembly

Shape Testing

Buoy Shape Considerations

Choose shape based on• Lowest Damping Ratio• Closest Natural Frequency

to Desired Range

Verify Mathematical Model

Justify Assumptions

Drop Test

• Dropped Shapes from set height

• Measured Vertical Displacement

• Characterized • natural frequency • damping ratio

• Verified Mathematical Model

Experimental Correlation

Cylinder1 Curve Fit

0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.2000

1.4000

1.6000

0.0000 0.1000 0.2000 0.3000 0.4000 0.5000 0.6000 0.7000 0.8000 0.9000 1.0000

Time (s)

No

rmali

zed

Dis

pla

cem

en

t

Experimental Results Second Order Response Model Results

Damping Ratio Variation

Damping Ratio vs. Mass

0.000

0.100

0.200

0.300

0.400

0.500

0.600

0.700

0.143 0.193 0.243 0.293

Mass (Kg)

Dam

pin

g R

atio

Sphere Cone Cylinder Teardrop Airfoil

Natural Frequency Variation

Natural Frequency Vs. Mass

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

0.143 0.193 0.243 0.293

Mass (g)

Nat

ura

l F

req

uen

cy (

rad

/s)

Sphere Cone Cylinder Teardrop Airfoil

DOMINANT FREQUENCIES

Desired Range

Fourier Amplitude vs. FrequencyFor a Buoy at 44.35° by 64.29° in a Depth of 12 Meters of Sea Water

0

2

4

6

8

10

12

14

16

18

20

0 10 20 30 40 50 60 70 80 90 100

Frequency (Hz)

Fo

uri

er

Am

plitu

de (

dB

)

Shape Conclusions

• Original Testing Results• Cylinder

• Revised Testing • Cone

• Mishap During Manufacturing of Second Shape

Linear Generator

Linear Generator Design Goal

• produce a linear generator capable of functioning in multiple wave heights

• accomplished by the use of annular (ring-shaped) magnets and the orientation of the magnets

Linear Generator Testing Part 1Predicted Value for Magnetic Flux

Magnet Flux Rating

=1.21Tesla

inner

inner

B =.351 1.21T

B =0.42T

=1.543ratioA

11 100% 35.1%

1.54innerA

Linear Generator Testing Part 1Drop Testing For Determination of Flux

• Initial drop testing was performed to try to quantify the amount of flux interacting with coils

• Single magnet dropped at fixed heights for constant velocity

• 100 turns of copper• Attached to oscilloscope to obtain

a reading for maximum voltage

Linear Generator Testing Part 1Actual Value for Magnetic Flux

• From the drop testing, peak voltage is determined

• Velocity, length of coil, and number of turns are known and constant

VB

Lnv

Average Magnetic Flux = 0.46T

0.46 0.42100% 8.7%

.42

Matlab Validation

Drop Testing With Pod

• Same type of testing as with single magnet

• Only one velocity could be tested

Average Magnetic Flux:

B=0.51T

Mathematical Model

RIPA In Action

Mathematical Modeling

• MatLab Simulink• Invaluable tool to build

a model

• Fundamental formulas implemented• Built up simulator starting

with first principles• Specialized simulators

for specific tests

Model Verification

• Simulated lab conditions to ensure that the model accurately predicts results

• Model validated using multiple test situations• Step Input simulation

to characterize buoy shape dynamics• Drop test simulation

to characterize magnet interaction

Model Verification

• Voltage comparison

Extrapolated Results

• Simulator used to determine requirements to meet project goal of 100W

Extrapolated Results

• Magnet strength and scale not changed• Buoy dimensions changed• Electrical characteristics modified• Larger amplitude wave input

• Requires more coils to accommodate longer stroke

• Longer period waves

Closing Remarks

Extrapolations

• Wave Input• 0.5 m amplitude, 1.5 sec period

• Device Configuration• 16 inch buoy diameter• 500 turns per coil with reduced impedance• 50 coils• 9 sets of magnets

• Average Output• 100W

Cost

• Material Changes• Magnets• Fiberglass• Inner core Material

Cost (CND)

841.25$

152.90$

143.16$

54.00$

137.94$ 1,329.24$

TotalInner Core

Total

ShaftTotal

BuoyTotal

PartBudget

Linear Generator

Alignment SystemTotal

Total

Design Requirements

• Requirements Met• Scalability• Serviceability• Simplicity• Mean power output of 100W

• Requirements Not Met• Cost less than $1,000.00• Resilient to adverse weather conditions

Thank You

• Sponsor• Mr. Richard Rachals

• Supervisors• Dr. Robert Bauer• Dr. Larry Hughes

• Technicians• Angus Macpherson• Peter Jones• Greg Jollimore• Stuart Carr• Brian Liekens

• Outside Resource• Dr. Timothy Little

• Mechanical Engineering Department

QUESTIONS???