Slide 110/21/2008
Union College
Design and Implementation of a Micro-Wind Turbine for the Union
College CampusKevin Donovan and Malysa Cheng
Advisors: Professors John Spinelli and Richard Wilk
ECE 498 Presentation
19 March 2009
Slide 210/21/2008
Union College
Project Goals
Design and manufacture a micro-wind turbine to generate electricity for an on-campus application
Generate a useable amount of electric powerDemonstrate turbine in a visible location on campusEvaluate Union College’s potential for wind power generation
Slide 310/21/2008
Union College
Wind Speeds at Union
Wind speeds are not desirable for wind power generation
Most wind speeds occur at 1 mph
Most high speeds occur at 3 mph
High gusts up to 56 mph
-% of the time speed is at 5 mph
Slide 410/21/2008
Union College
Shows seasonal fluctuations in wind speeds
Summer season is least desirable
Winter Season better for wind turbine
performance
Wind Speeds at Union
Slide 510/21/2008
Union College
Wind Tunnel Testing
Clocking IssuesNeeded 2nd
Generation Models
Too much resistance with torque setup
Successfully completed rotations
Final design based off 2nd gen models
Slide 610/21/2008
Union College
Hybrid VAWT
Darriues Wind TurbinesNot self-starting
Uses drag and lift forcesHighest VAWT Efficiency
Savonius Wind TurbinesSelf Starting
Uses drag forcesLower efficiency
Slide 710/21/2008
Union College
Gear Ratio
Expect approximately 100 RPMs from wind turbine
Beveled gear set• Expensive• Not easy to switch
out
Chain and sprocket• Cheaper• Easy to switch out
sprocket sizes
Timing Belt• Cheaper• Easier to switch out
Less noise than chains
V Belt• Cheaper• Easier to switch out• Less noise than
chains• Less resistance
Slide 810/21/2008
Union College
Electrical System
Alternator Rectifier Battery Bank Inverter Load DC-DC
Converter
Slide 910/21/2008
Union College
Electrical System
Wind Torque
AC DC Storage
AC Outlet
Alternator Rectifier Battery Bank Inverter Load DC-DC
Converter
Slide 1010/21/2008
Union College
Electrical System
Wind Torque
AC DC Storage
AC Outlet
• Design Goals• Safely charge battery• Broaden range of usable wind speeds• Maximize system efficiency• Synchronized data acquisition
Alternator Rectifier Battery Bank Inverter Load DC-DC
Converter
Slide 1110/21/2008
Union College
Electrical System
Wind Torque
AC DC Storage
AC Outlet
• Design Goals• Safely charge battery• Broaden range of usable wind speeds• Maximize system efficiency• Synchronized data acquisition
Alternator Rectifier Battery Bank Inverter Load DC-DC
Converter
Slide 1210/21/2008
Union College
Generator Selection
Wind
Torque AC DC Stor
age AC Outlet
Design Considerations Generators vs. Alternators Starting Torque Direct-Drive vs. Gear-Drive Power Curves
Conclusions Alternators can produce three phase AC
More efficient Allows for control over rectification
Low starting torque was critical Single step gear
Unavoidable given project magnitude and region’s average wind speeds
Needed higher voltages at lower speeds
Source: Gin Long Permanent Magnet GeneratorsSite: http://www.ginlong.com
Slide 1310/21/2008
Union College
Generator Selection
Wind
Torque AC DC Stor
age AC Outlet
Decision WindBlue DC-540
Three phase AC Rewound stator provides higher voltages at lower RPMs
12 V at 150 RPM Low starting torque
Source: Wind Blue PowerSite: http://www.windbluepower.com/
0 50 100 150 200 250 3000
5
10
15
20
25
Voltage vs. RPMs
RPMs
Vo
lta
ge
(V
)
180 200 220 240 260 280 3000
0.5
1
1.5
2
Current vs. Torque
Torque (oz-in)
Cu
rre
nt
(A)
Slide 1410/21/2008
Union College
Alternator Testing
• DC motor used to drive alternator• Required heavy-duty power source
• Power in, torque, RPM, and power out data collected
• Used to create current, voltage, and efficiency curves
Slide 1510/21/2008
Union College
Rectification
Wind
Torque AC DC Stor
age AC Outlet
Design Considerations Three-phase AC output from alternator Heat dissipation
Decision Three-phase full-wave bridge rectifier Large heat sink can easily dissipate expected
power levels
Source: Lessons in Electronic CircuitsSite: http://www.ibiblio.org/kuphaldt/electricCircuits/Semi/03269.png
Source: Wind Blue PowerSite: http://www.windbluepower.com/
Slide 1610/21/2008
Union College
DC-DC Converter
Wind
Torque AC DC Stor
age AC Outlet
Design ConsiderationsWind speed is not constant
Alternator will output varying amounts of power Union’s average wind speeds are low but not always
Battery bank requires different current ratings Depends upon depth of discharge
Consistent overcharging of battery bank leads to premature failure Charging voltage needs to stay within .7 V of the nominal battery voltage
Voltage regulation is critical
Slide 1710/21/2008
Union College
DC-DC Converter
OptionsLinear voltage regulator
Simpler design Input must be at least 3 V above output voltage Low efficiency
Switch-mode power converter Various topologies for outputs above or below inputs High efficient More complex
DecisionBuck/Boost switch-mode converter
Raises or lowers input voltage to obtain desired output Controlled by altering switch duty cycle
Wind
Torque AC DC Stor
age AC Outlet
Slide 1810/21/2008
Union College
DC-DC Converter
Basic Topology
Vin Vout
Vin Vout Vin Vout
D
DVV InOut
1 D
DII InOut
1
where D is duty cycle
On State Off State
Wind
Torque AC DC Stor
age AC Outlet
Slide 1910/21/2008
Union College
DC-DC Converter
Continuous Conduction Mode Discontinuous Conduction Modevs.
Wind
Torque AC DC Stor
age AC Outlet
Source: Wiki CommonsSite: http://en.wikipedia.org/wiki/Buck%E2%80%93boost_converter
Slide 2010/21/2008
Union College
DC-DC Converter
Goals• Operate in continuous conduction mode• Maintain a low output voltage ripple• Effectively regulate voltages between 9-15V to a nominal 12.5V
Design
LS
In
If
DVL
CS
Out
Vf
DIC
Where fs is the switching frequency IL is the inductor current ripple VC is the capacitor voltage ripple
MultiSim buck/boost schematic
Wind
Torque AC DC Stor
age AC Outlet
Slide 2110/21/2008
Union College
Simulated Results
Slide 2210/21/2008
Union College
Implementation
• Switching frequency is limited by BASIC STAMP 2px PWMPAL coprocessor– Duty cycle is controllable only up to 2kHz
• Inductor series resistance is a serious limiting factor• Trouble driving power MOSFET
– Transistor capacitance slows turn-off time, limiting effective duty cycle– Driver ICs may increase performance
• NS754410, used as a voltage-controlled switch, also exhibits slow shut off time• Current implementation only allows for output voltage adjustment up to +/-while
still operating in continuous conduction mode
Slide 2310/21/2008
Union College
Battery Selection
Wind
Torque AC DC Stor
age AC Outlet
Design Considerations Charging safety Batteries may be thoroughly discharged over lifecycle Temperature
Decision 37Ah Sealed AGM battery Robust to deep discharging Superior cold weather performance Cheaper than gel cell battery with
comparable performance
Source: MK BatterySite: http://www.mkbattery.com/
Slide 2410/21/2008
Union College
Inverter Selection
Wind
Torque AC DC Stor
age AC Outlet
Design Considerations Will determine power output quality Sine Wave vs. Modified Sine Wave vs.
Square Wave 12v DC input, 120V 60Hz output
Decision AIMS 300W pure sine wave inverter
Cost was comparable to modified sine wave inverter
Will allow for more diverse loads 90% efficient
Source: AIMS PowerSite: http://www.aimscorp.net/
Slide 2510/21/2008
Union College
Load Selection
Wind
Torque AC DC Stor
age AC Outlet
Design Considerations Contribute to campus in some way Promote sustainability at Union Relatively low power consumption
Decision Programmable LED sign
Draws 1A at 120V 60Hz
Slide 2610/21/2008
Union College
Datalogging
Design Requirements• Synchronized sensing of wind speed, turbine RPMs, and charging voltage• External storage for ease of use and large amounts of data• Microcontroller-based
Implementation with the BASIC Stamp 2px• NRG #40 anemometer outputs a frequency proportional to
wind speed• Tested in wind tunnel, • Accurate within 1 MPH
• Hall effect transistor used to sense turbine rotations• Successfully implemented in tested against strobe tachometer• Results were comparable
• Voltage sensing capability through operational amplifier circuit and A/D converter
• Memory-stick datalogger successfully records data into a text file for importation into Excel
Source: ParallaxSite: http://www.Parallax.com
Slide 2710/21/2008
Union College
Continuing Development
• Buck/boost converter implementation– Investigating better switch drivers– Inductors with lower series resistance
• Integration with final micro-turbine prototype• Demonstration on campus
Slide 2810/21/2008
Union College
Budget
Mechanical Cost
Darrieus
Wooden Skeleton 20.00
Top/Bottom Sheet 273.06
Lexan Sheet 17.48
Shaft 84.91
Savonius
Ribs 26.02
Blades 101.70
Other
Nuts and Bolts 30.00
Mounting/Gearing 125.00
Electrical Cost
Alternator 239.00
Rectifier with Heat Sink 14.00
Passive Components Supplied by EE Dept.
Board of Education Supplied by EE Dept.
BASIC Stamp 2ps Supplied by EE Dept.
PWMPAL 29.99
Anemometer 160.00
Hall Effect Transistor 4.99
3/8” Magnet .79
AGM Deep Cycle Battery 73.66
Pure Sine Wave Inverter 134.00
LED Sign Supplied by Facilities
Total
$1363.10
Slide 2910/21/2008
Union College
References
• Kassakian, John. Principles of Power Electronics. Reading, MA: Addison-Wesley, 1991
• Ang, Simon. Power Switching-Converters. New York: Marcel Dekker, 1995
• Lessons in Electronic Circuits, http://www.ibiblio.org/kuphaldt/electricCircuits/Semi/03269.png
• WindBlue Power, http://www.windbluepower.com/• Source: Wiki Commons, http://en.wikipedia.org/wiki/Buck
%E2%80%93boost_converter• MK Battery, http://www.mkbattery.com/• Gin Long Permanent Magnet Generators, http://www.ginlong.com• AIMS Power, http://www.aimscorp.net/• Parallax, http://www.Parallax.com
Slide 3010/21/2008
Union College
Questions?
