Marine Wave Power Generation

Marine Wave PowerGeneration

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AcknowledgementsWe would like to thank the following groups that help made this project possibleLaurie Rynanen and the group at FABMAR METALSMartin Sprockets Canadian BearingsEngineering Department at Lakehead University

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Pre ProjectAll three of us had our first choice in Power Systems for our Degree Project.Couple of ideas presented to Dr. UddinFinally selected Wave Power GenerationTurned out to be Mechanical heavy but we still enjoyed and learned a lot along the process

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What is Wave-GenerationEnergy produced on or near surface of oceans wavesEnergy is transmitted through WavesIn this case, the transmission medium is waterApplications:Desalination PlantsPower GeneratorsWater Pumps

-Light is a wave-What makes our project unique is that to date there are only a handful of experimental wave generator plants in operation around the world.4

Canadian ConnectionNatural Resources Canada Report

190 potential tidal power sites have been identified with total combined estimated capacity of 42,000 MW.

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Conceptual DesignsFairly large number of conceptual designs Attenuator Type

-From 1855 to 1973 there were already 340 patents for different concepts were filed in the UK aloneAttenuator type floats device moves along with the parallel wave. These types of device capture energy relative motion of the two moving objects as the wave passes them.This type is designed to absorb energy from up and down motion through the water surface. Here buoyant movement through mounted permanent magnets.6

Pelamis wave generatorConnected sections flex and bend as waves pass, generating electricity

ThePelamis Wave Energy Converteris a technology that uses the motion ofocean surface waves to create electricity. The machine is made up of connected sections which flex and bend as waves pass; it is this motion which is used to generate electricity.The machine, which was rated at 750kW, was the world's first offshorewave powermachine to generate electricity into the grid system.7

Current ModelsPoint Absorber Type

There are a fairly large number of concept designs for capturing wave energy. The most popular of these are usually designs based around the attenuator type or the point absorber type. 8

CETOOnly Wave-energy technology that is:Fully Submerged.Generates electricityDesalinates water.

Named after Greek Ocean Goddess

Submerged buoys are moved by the ocean swell, driving pumps that pressurize seawater delivered ashore by a subsea pipeline. Once onshore, the high-pressure seawater is used to drive hydro-electric turbines, generating electricity.9

SustainabilityEnergy demand will only grow

Need to utilize green energy sooner than laterWave energy is becoming more and more feasibleSustainability in earth resources can be achieved with wave power generation

The world needs sources of energy that have low carbon demands, and wet renewables represent a significant resource. All renewable energy systems impose changes to the environment which need to be balanced against the potential to deliver very significant quantities of low carbon energy. 10

Design GoalsCreate a design similar to attenuator typeAvoid the use of hydraulic oil in power transfer Absorb horizontal energy from wave as well as vertical energy Design Power Electronic circuit to control output electrical PowerUse of a PM DC generator to avoid having to supply field current

Design Block Diagram

Absorb vertical wave energy

Absorb horizontal Wave energy

Change in to rotational energy

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Alternated to electrical energy

Wave

Mechanical DesignDesign heavily relied on Archimedes PrincipleAny body immersed in a fluid is subject to an upward force equal to the displaced weight of the fluidTorque induced between two floating bodies by changes in height Changes in height not always same amplitudeMust work with varying wave heights

Archemedes principle : any body immersed in a fluid is subject to an upwards force

By having two objects floating in relation to each other a torque between the two objects could be induced into a shaft on one of the objects as the height relation between the two objects changed13

Mechanical Design A float is connected to a Primary shaft on the generating unitAs float moves in relation to unit the shaft will turn through a partial arcA secondary shaft is coupled to the primary shaft and will turn the opposite direction to the primarys Both the primary and secondary shafts are connected to a main shaft through ratcheting hub assemblies

Mechanical DesignThe hub mechanisms only transmit power in one direction and slip in the other direction

The Hubs will allow the main shaft to always rotate the same direction while power is being transmitted to itIf there is a float connected to other side of unit the power may be doubled

Mechanical Power CalculationsCalculations for 100W with unit exposed to a sine wave at 1Hz with a height to lift the float from rest to 100mm.Length of arm = 200mm

Mechanical Power CalculationsTorque required for 50W:

Force required from water:

Mass required:

Volume of water displaced:Calculations show the generating units and floats need a mass of 12.13kg and displace 0.1213 to develop the required power

Unit Stability The center of gravity of each unit needed to be carefully calculatedA center of gravity placed in the wrong position could cause the unit to flip overA center of gravity properly placed could create a very strong righting lever to help the unit rollTo help with calculating stability a MATLAB program was created

Unit Stability

Unit Stability The Program allows for changes in physical parameters of the unitWidth, height, mass, height of center of gravity Allows for changing the list angle of the unitProgram displays the buoyancy point with a red X, center of gravity with a blue X and displays the righting lever acting on the unitIn this program a negative righting lever shows the unit trying to right itself and a positive value will mean it will capsize

Gearing Design Spur gears from Martin Sprockets were chosenRatings for gears were only given in HP/100rpm so conversions were done to check for the allowable torque The generator selected for the project had a Ke= 0.0706 V/rad/S If we wanted the generator to supply 24V at a full power of 100W the final = 339.9 rad/sThe gearing ratios were all selected to help raise the 2.1 rad/s to this value

Mechanical Design End View

Mechanical Design Top View

The general operation of this DC-DC converter is that the required Load voltage and the input voltage dictates the duty cycle for the switching of the MOSFET to charge the inductor to step up thevoltage.Electrical Circuit Design

Electrical Circuit DesignBoost Converter DesignDuty Cycle

Electrical Circuit DesignInductor calculation:@ 10W@ 100WBased on this these values and available parts an inductor value of 154H was chosen.

Electrical Circuit DesignCapacitor calculation:@ 10W@ 100WWe have chosen 1000F capacitor for this circuit to help dampen any input power fluctuations from the waves.

Electrical Circuit DesignLT Spice Simulation:

@ 10W

Electrical Circuit Design

@ 100W

Electrical Circuit Design

Electrical Circuit DesignOnce the desired output power is calculated, the controller calculates what the desired output voltage is for that power and this value becomes the set point.The load voltage is then sampled and compared to the set point and an error value is calculated. This error value is then fed into a PID control program written into the controller and it determines what the control output should be.

Electrical Circuit DesignThe PWM signal out of this controller is only at a value of 0 to 3.3V so a MOSFET driver was required to drive the IRF540N MOSFET chosen for this project. microcontroller needed to be high impedance to protect it, so after the voltage dividers, the signals were fed into op-amp(LMC 6482) that were supplied by the 3.3V regulator build into the Teensy controller. This prevented any dangerous voltage spikes that may occur from reaching the Teensy by just clipping the signal.

Electrical Circuit Design

Deviations from DesignPrototype was not constructed exactly as designed Major deviations wereUsing belts and pulleys instead of gears for transmitting power to main gearThe overall dimensions of unit are larger The mass of the prototype was over calculated values by 106%Only one working side was constructed

Test ResultsSome test results of the unit

Test Results The results from the tests were poor while under loadThe cause of this was the V-belts slipping when exposed to a loadMany of the best results were in earlier tests as the belts began slipping more as the time went onAverage power output while powering a load was around 5WThis was only for one side so it may be considered to be double if both sides were working

Test Results

SafetyElectrical system safetyBased on our calculated results combined with a safety factor we decided on 2.5A fuses for the output to the load and from the supply battery.

Floating object safetyNavigation Protection Act (NPA)Navigation Protection Program (NPP)

Project CostsTotal amount spent on project -$1600Major expenses were: Gearbox - $348Pulleys and bearings - $250Microcontrollers -$100Tools for construction -$200

Economic Cost and Profitability Analysis

Economic Cost and Profitability AnalysisScalingNew Cost recovery period is

With Archimedes` principle of floating bodies, we can increase the scale of our project with the increase in mass and volume of displacement while still utilizing the same original model. 41

Questions?