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???
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