Iowa State University
Wind Turbine Energy Conversion
System Design and Integration
Project Plan
Project Number
May10-17
Team Members
Brandon Janssen
Kenny Thelen
Hassan Burawi
Elsammani Ahmed
Advisor
Dr. Venkataramana Ajjarapu
Client
ISU Department of Electrical and Computer Engineering
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DISCLAIMER: This document was developed as a part of the requirements of an
Electrical and Computer engineering course at Iowa State University, Ames, Iowa. This
document does not constitute a professional engineering design or a professional land
surveying document. Although the information is intended to be accurate, the
associated students, faculty, and Iowa State University make no claims, promises, or
guarantees about the accuracy, completeness, quality, or adequacy of the information.
The user of this document shall ensure that any such use does not violate any laws with
regard to professional licensing and certification requirements. This use includes any
work resulting from this student-prepared document that is required to be under the
responsible charge of a licensed engineer or surveyor. This document is copyrighted by
the students who produced this document and the associated faculty advisors. No part
may be reproduced without the written permission of the Senior Design course
coordinator.
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Contents
Executive Summary ..................................................................................................................... 5
Problem Statement ....................................................................................................................... 5
Operating Environment .............................................................................................................. 6
Intended Users and Uses ............................................................................................................ 6
Expected End Product and Deliverables .................................................................................. 6
Requirements ................................................................................................................................ 7
Functional requirements ......................................................................................................... 7
Non-functional requirements ................................................................................................. 7
Market Survey .............................................................................................................................. 7
Resources and Schedule .............................................................................................................. 8
Parts ............................................................................................................................................ 8
Hours.......................................................................................................................................... 8
Schedule ..................................................................................................................................... 9
Design .......................................................................................................................................... 10
Conceptual Sketch/Update Block Diagram ....................................................................... 10
Conceptual Sketch Figure 1 ............................................................................................... 10
Wind Turbine .......................................................................................................................... 11
Inverter..................................................................................................................................... 11
Controls.................................................................................................................................... 12
Interface ................................................................................................................................... 12
DC Sensors .............................................................................................................................. 13
RPM Sensor ............................................................................................................................. 13
RPM Sensor Circuit Schematic ......................................................................................... 14
Three Situations of Concern.................................................................................................. 16
Implementation .......................................................................................................................... 17
Interface ................................................................................................................................... 17
DC Sensors .............................................................................................................................. 19
RPM Sensor ............................................................................................................................. 20
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Power Supply .......................................................................................................................... 20
Three-Phase Induction Motor ............................................................................................... 21
Press-fit Precision Metal Bellows Couplings: ..................................................................... 21
Load .......................................................................................................................................... 22
Testing ......................................................................................................................................... 23
Interface ................................................................................................................................... 23
DC Sensors .............................................................................................................................. 23
RPM Sensor ............................................................................................................................. 23
Complete System .................................................................................................................... 24
Power vs. Speed ...................................................................................................................... 24
Conclusion .................................................................................................................................. 25
Operation Manual ...................................................................................................................... 26
Appendix ..................................................................................................................................... 29
LEM LA 55-P Current Transducer ....................................................................................... 29
NI 6008 USB............................................................................................................................. 30
Outback GTFX2524 Inverter ................................................................................................. 31
Southwest Windpower Air X 400 ........................................................................................ 32
Display Setup .......................................................................................................................... 33
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Executive Summary
With renewable energy becoming an increasingly popular source for our changing
energy and environmental needs, Iowa State University must do its’ part. To show the
universities commitment in conserving and minimizing impact on global climate
change, Iowa State University does it’s part in wind energy research.
Our team plans to assist in the design and implementation of this wind turbine system,
as well develop it as an educational tool for the university. Dr. Ajjarapu wishes to use
the wind turbine purchased by the previous team and simulate an actual wind powered
environment inside the lab. This will include designing sensors for the system, a user
interface, as well as a means to protect the system while utilizing the maximum amount
of wind.
Unfortunately, our team lost a member this semester: Luke Lehman. He received a Coop offer from OPPD and we wish him the best.
Problem Statement
This is a continuation project. The ongoing project involved the design of a wind
turbine energy conversion system that can be integrated to electrical power grid in the
Coover hall power lab. The generator is rated around 400W. The wind turbine was to
be installed on the side of Coover hall, but upon further investigation, the budget
would not allow this to happen. All the protection and control aspects of the conversion
system become part of the design.
The extension of the project was to include supplying a standalone load in conjunction
with grid supply. After the previous team left, it was discovered that many portions of
the project were not left behind, and some were either unnecessary or did not work as
intended. The user interface designed by the previous team was lost, the charge control
that was designed to protect the batteries was insufficient, and the AC sensors did not
function properly. It was left to our team to redo many of these mistakes and
unfortunate miscommunications for our own project.
Another major point of concern is the wind turbines internal controls. We wish to
control the way the turbine operates ourselves, to maximize the use of this project. The
internal control that is our biggest concern is the regulation mode of the turbine, which
completely shuts the turbine off when the battery bank is full. We wish to work around
this control and implement our own.
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Operating Environment
The wind turbine and control system are no longer intended for outside use, so all
prototypes designed will only be designed for indoor operation. Although our designs
will not include outdoor use, we wish them to expandable and easy enough to modify
to do so.
All components purchased by the previous team will be placed inside and with close
proximity to the wind turbine, so transmission infrastructure will be minimal.
Intended Users and Uses
Intended Users:
The wind turbine system will primarily be used by Dr. Ajjarapu as well as his research
assistants. It may also be used in future Senior Design projects so it must be
expandable.
Intended Uses:
The system will be used to simulate wind powered generation. It will be used to study
the implementation of small wind turbines and the characteristics the turbine shows
during operation. This system also simulates a situation where the turbine requires a
battery bank as a backup energy source and the issues that come with that requirement.
Expected End Product and Deliverables
Wind turbine power for standalone load
The wind turbine (complete with control systems) will be able to operate a standalone
load of our choosing (such as an induction motor or resistive load)
Wind power simulation
The wind turbine will be driven by an outside source that is easily controlled. This will
be a 3-phase induction motor coupled to the drive shaft of the turbine. A stable and
useable test-bed for the turbine will be the result.
Speed, Current, and Voltage Measurements
Various measurements will be made and displayed through a user interface.
Utilization of Wind Power
Some of the wind turbines internal controls will be turned off and replaced with our
own means. These new controls will still allow the system to operate safely but more
efficiently.
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Requirements
Functional requirements
FR01 The turbine will generate a 24V DC output.
FR02 The turbine will generate a 400W peak output.
FR03 Wind power will be simulated by driving the turbine by some other mechanical
means.
FR04 The wind turbine will not turn off when the battery bank is full, instead, the
wind power that is available will be utilized the best it can.
FR05 The turbine will power a AC stand-alone load by means of an inverter
FR06 A user interface will control the wind turbine output and display of various
system measurements (current, voltage, turbine speed, etc.)
FR07 Various sensors will assist in displaying battery current, turbine current, turbine
speed, system voltage, and power levels.
Non-functional requirements
NFR01 All wiring and electrical work complies with university and state electrical
codes and regulations
NFR02 Battery bank is in controlled temperature and stable environment
NFR03 The battery bank is properly protected from over and under-charging
Market Survey
In today’s world, the need for alternative, environmentally friendly energy generation
has never been greater. The Department of Energy (DOE) has set plans and taken the
initiative to have wind energy account for 20% of total energy generation or 300GW by
capacity in the United States by 2030. This would cause a huge increase in demand for
more efficient wind turbine designs to maximize energy generation while minimizing
losses.
Small scale wind farms are also becoming more popular. Although most systems today
are “off-grid” types systems, demand is growing for “on-grid” systems that will allow
the user to give energy back to the grid and use the grid as backup.
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Resources and Schedule
Parts
It was important that we kept to our allotted $250 budget for this project, since the
previous team needed additional funds for the cost of the turbine, inverter, and battery
bank. Following is a breakdown of part costs:
Item
Cost
Coupling
$112
Current Transducer
$21
Stop Switch
$16
Display Materials
$15
Kikusui Power Supply
$0
3-phase AC Motor
$0
Total
$164
Hours
Here is a breakdown of hours spent by percentage of each member.
Hours
23%
22%
28%
Brandon
Kenny
27%
Hassan
Elsammani
Hours Breakdown
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Schedule
The following is the work schedule followed for the second semester of our project.
Work Schedule
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Design
Conceptual Sketch/Update Block Diagram
Conceptual Sketch Figure 1
This is the original concept sketch for the first semester. To illustrate the changes the
project went through, it can be compared to an update block diagram below.
Update Block Diagram
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Wind Turbine
The previous team chose to purchase a wind turbine made for this type of application.
The wind turbine is an Air X 400 W unit.
The Air X 400 unit is designed primarily as a means to charge a battery bank which may
be used to power electrical devices. This project wishes to emphasize it as a primary
source of energy, with a backup battery source. This means there are features of the
turbine that are useful, but several that can be seen as detrimental to our design project:
Battery Bank Requirement
The turbine requires a battery bank to function. This is not entirely undesired but may
be an issue. Instead of power being directly used from the turbine, it is supplemented
by the battery bank which is charged by the turbine.
Regulation Mode
The turbine can sense the voltage level of the battery bank. When this voltage level is
too high (the batter bank is fully charged), the turbine enters a regulation mode. This
mode cuts the output of the turbine until the voltage of the battery bank reaches a lower
level. This is undesirable, given that we wish to make use of the wind whenever is
available, not just when the battery bank needs charging. Thankfully, this mode can
effectively be turned off my manually setting the voltage at which the turbine enters
regulation mode to one that is so high that there is no concern that it will be reached.
This is done by using a DC power supply connected to the leads of the turbine and
turning a potentiometer on the casing.
Controllability
The controls that allow the turbine to function, such as the voltage regulation system,
reside inside the casing. This removes the ability to control certain aspects of the
turbine that may be useful to the project. The casing cannot be opened and details or
schematic of the controls cannot be obtained from the manufacturer.
Inverter
The previous group also chose an inverter for their project. It as an Outback GTFX2425.
This inverter will be used to transform the DC power from the wind turbine to useable
120 VAC power to connect with the grid at Coover Hall or a standalone load within
Coover Hall. It is important to note that this is a hybrid inverter that is capable of both
these scenarios. It does not require an outside 60 Hz reference signal if it’s not
connected to the grid. Many inverters are strictly on or off grid.
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Controls
The previous team designed a charge controller for the wind turbine system. The
controller trips a relay on the other side of the inverter when the battery voltage reaches
too low of a level. Our team found this to be unnecessary because of the inverter’s
internal control that automatically cuts off the load once the batteries reach 21 volts. So
this controller has been removed without any consequence to the system’s
requirements.
Interface
The previous team had design a full interface for use with this project. Originally, our
plans were to expand upon interface, but when the semester began it was discovered
that the team had not left the interface with anyone, even our advisor Dr. Ajjarapu. So
it was necessary that we started from scratch.
The user interface is designed within LabVIEW. This gave us a gradual learning curve
so that we could have it operational quickly. The NI-6008 DAQ is used to bring in
readings from various sensors. The interface not only has to display measurements, but
also control the output of an adjustable power supply. Luckily, a library of LabVIEW
functions were provided for our power supply so design for this portion was minimal.
The design of the input portion of the display was done by implementing tasks in
LabVIEW’s block diagram editor. Each channel that was read from the DAQ was
designated to get the appropriate reading. Some of these readings require
mathematical manipulation to be correct. The values are then displayed using gauges
on the front panel.
Interface Front Panel
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DC Sensors
The DC current of turbine and battery are measured using 2 DC current transducers.
Both are of the same type made by LEM (LA 55-P). The DC current transducer is rated
at ±70A. It uses a galvanic isolation technology in which the high current being
measured is not in contact with the electronic circuit outputting the low current. This
model of DC current transducer also has low power consumption with its terminal
connected to ±15V and can handle up to 8-gauge wire. When used to measure a 50 A
current, The current transducer produces a 50 mA as an output signal, operating at
1:1000 ratio between input and output currents.
LA 55-P Current Transducer
RPM Sensor
The RPM sensor became a requirement of this project as of the second semester. This
means all design, testing, and implementation had to be done within a short time
period. At first the RPM was intended to be designed as a standalone unit that would
calculate and transmit an RPM value to a PC using a microcontroller and RS- 232
standards. Through group and advisor discussion this solution was discovered to be
too complex for our needs and resources (mainly time).
The general design was then switch to a simple pulse generator feeding into the built-in
counter of the NI-6008 DAQ. This solution is less accurate and is more limited on
maximum RPM measurements. Since our turbine will reach a max speed of
approximately 2000 RPM, and will only require an estimated RPM value, these
drawbacks are acceptable.
The RPM sensor is design in separate hardware and software components:
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Hardware
Two infrared LEDs are used to generate the pulse signal required for the DAQ counter.
This is a simple design that is popular in proximity sensing among other things. A
comparator circuit is used as the receiver and a directly powered LED as the
transmitter. The two LEDs are positioned next to each other. When a reflective surface
is in front them, a voltage drop is induced upon the receiver LED. The comparator
circuit then enters the ON state and outputs a voltage depending on the Vcc used. A
load with a LED is at the output to provide a visual reference for testing.
The circuit diagram is given below, with actual resistor values used. An LM 358
operational amplifier was used for its’ good output voltage swing of 0V DC to Vcc-1.5V
DC. The 0V output is important for the counter inside the DAQ to work properly. A
Vcc of 5V DC is used.
RPM Sensor Circuit Schematic
Software
The counter of the DAQ counts the falling edges it receives from the input signal. The
processing of the RPM value is all done within LabVIEW. The counter of the DAQ is
continuously sampled in LabVIEW and is reset every 3 seconds. The number that is
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read from the counter is divided by the elapsed time to result in a frequency. This is
then multiplied by 60, resulting in the RPM.
Due to rapid variations in the calculated RPM value seen during testing, a simple
averaging method is used on the output to achieve a smoother and more readable
display. This is done by filling an array with 20 values and displaying the average of
them. This same method was used in other portions of the display that suffered from
noisy signals from the DAQ. Although it results in an output that is slower to react to
rapid changes, it is satisfactory to our project needs.
RPM Sensor Block Diagram
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Three Situations of Concern
As said before, the wind turbine has a built in charge controller that effectively turns off
the turbine once the battery bank reaches a certain voltage. This means that if there is
available wind, it cannot be use to supply a load because the battery bank is full. To
illustrate what exactly this means, we have outline three situations where we would
rather have the turbine keep running rather than shut off. In all these cases, we
consider the battery bank completely full so we do not wish to charge it.
Wind Power=Load
In this case, when available turbine power is equal to the load demand, we would most
definitely want to utilize the wind power that is available. All the power produced by
the turbine will supply the load, with none of it left to charge the battery. According to
basic KCL principles, all of the power will flow into the load.
Wind Power<Load
The same applies to the situation where wind power is less than the load. According to
KCL, all of the available wind power will flow to the load, with the remainder needed
coming from the battery bank.
Wind Power>Load
This is the case where outside action is needed. If wind power is greater than the load,
than the remaining current will flow into the battery bank, which is full as we stated
earlier. If no action is taken, the battery bank will be damaged from overcharging.
What can be done, is a simulated version of pitch control.
In larger turbines, the pitch of the blades may be adjusted to change the output of the
turbine to an extent. In our case, we are driving the turbine with an induction motor to
simulate wind power, so we may also simulate pitch control by adjusting the speed at
which we spin the turbine.
All these situations make the case for removing the regulation mode from the turbine
and using our own control to simulate pitch control. Regulation mode has effectively
been removed by adjusting its turn-on voltage to one which is higher than we actually
wish the batteries to reach, which is about 27V.
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Implementation
Interface
There were three different functions we wanted to accomplish with the interface. The
first function was to monitor the voltages, currents, power, and the RPM of the turbine
rotor. This was done by using the output signals from a DAQ. The DAQ we choose to
use was the NI USB-6008. It allowed us to input the voltages from the sensors into
LabVIEW.
In LabVIEW, we were able to modify the readings from the sensors to view the actual
values of voltage and current. The modifications were multiplying the voltage readings
by 4.9, and the current readings by 10. Because the values we were reading were DC, to
find the power we simply multiplied the calculated voltages and currents. The block
diagram for this part of the interface is below. The RPM part of LabVIEW was discussed
in the sensor part of this document.
Voltage, Current, and Power Readings
The next function was to control the three phase power supply that was used to control
the motor to drive the turbine. The PC communicates with the power supply through a
GPIB-USB cable. A LabVIEW library was provided to us by Zhongjian Kang. We
utilized two functions of this library. They were the ones that turned the output of the
power supply on and off and adjusted the voltage and frequency. We used the concept
of VF control to vary the speed of the motor. This is where voltage and frequency are
kept at a constant ratio, which results in a constant torque output as the speed of the
motor changes. Since we need to stay with the ratio of 220 Volts to 50 Hertz, the
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function was modified so that both the voltage and frequency were set by a single
input. The block diagram for the controls is pictured below.
Power Supply Control
The third function was the charge control. The charge control was done by if loops. The
first loop would compare the battery voltage to a given value, in our cases 27. If the
battery voltage is lower than 27 volts, the voltage supply would operate at the voltage
the user set. If the battery voltage was equal to or higher than 27 volts then it would
check the current. The current was compared to zero. If the current was positive, this
means the current was flowing out of the battery. Thus the voltage supply would
operate at the voltage the user set. If the current was negative, LabVIEW would subtract
a calculated amount of the voltage. This would lower the turbine output to a level at
which the current would begin to flow out of the batteries. The charge control is
pictured below
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DC Sensors
To measure the output current of the transducer a correction was made on the
connections of the previous design team’s work to get the right measurements of
currents. A 100 Ω resistor connected to the ground terminal of the current transducer
instead of a connection to current transducer terminals. The voltage across the resistor is
measured and then connected using a NI DAQ 6008 to the interface which displays
current values outputted by both turbine and battery. The transducer was soldered to a
PCB along with the resistor. A copy of data sheet with all the specification of LEM
current transducer is added to the appendix section.
DC Transducer Connections
A simple voltage divider is used to monitor the voltage of the system. It uses a 100 and
390 kilo ohm resistor. This ratio cannot directly be used in our calculations however,
due to the smaller than ideal internal resistance of the DAQ.
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RPM Sensor
The designed circuit was put together on a bread board for testing and then soldered to
a PCB. When this was tested several bad connections were found and fixed, but too
many problems were found near the completion of the project, and the more reliable
bread board circuit was used in final implementation.
RPM Sensor PCB
Power Supply
A Kikusui PCR-6000W 3-phase power supply was used to power the 3-phase induction
motor driving the turbine. The power supply is rated at 6000W and has an adjustable
voltage and frequency. Facilities modifications were needed to power the supply, as it
needed a 220 VAC source.
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Three-Phase Induction Motor
In order to simulate wind in the lab with the use of our wind turbine, we are using a
three phase induction motor connected to the turbine with the help of press-fit precision
metal bellows couplings. The motor is a basic three-phase induction SIEBER motor type
LS7/T. It is delta connected with a 0.37 kW rated power and 1.7 A rated current at 50
Hz. The motor operates at a maximum rated speed of 2800 rpm and has a power factor
of 0.8 cos φ. The motor also operates at a nominal output torque of 2N and a peak
output torque of 10N.
Motor coupled with turbine
Press-fit Precision Metal Bellows Couplings:
The press-fit couplings are used to connect the three phase induction motor with the
wind turbine. The couplings are model BK5 that are backlash-free and torsionally stiff
due to frictionally clamped connection and axial pretension of the tapered press-fit
segment. They are easy to mount and dismount and can be separated, as well
electrically and thermally insulated and have vibration damping properties. The
couplings are able to withstand a temperature range of -30 to 120°C (3.6 F to 270F) and
speeds ranging up to 10,000 rpm. In order to be easily mounted to the shaft of the
induction motor and the turbine, the coupling hub has been taped with a D2 bored of
0.625” and a size 18 thread.
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Load
To provide a load to the system, four 75W incandescent light bulbs were connected in
parallel after the inverter. A base load of 150W is always connected, with two
additional increments of 75W controlled by light switches available as well. This
provides a means to demonstrate the operation of the system as well as give another
visual reference of the power produced.
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Testing
Interface
To test if the set up would work to view the readings from the sensors, we hooked the
DAQ to voltage supplies. The voltage supplies were set to values we expected to obtain
from the turbine. This proved that our set up would work.
As soon as the sensors were complete, we hooked up the turbine and the batteries with
the sensors to begin testing. We found that the values of the measured voltages were
not correct. This was caused by the internal resistance of the DAQ not being a desirably
large value like a regular voltmeter would be. This caused some current leakage into
the DAQ which through our readings off. This was an easy fix. We simply measured
the actual number we would expect with a multimeter and figured out the ratio needed
for LabVIEW to display a proper value. We changed the values for the modifications to
multiply by 7.926.
We then used the coupling to hook the turbine to the motor to test the motor controls.
We ran into a problem. We were unable to run the motor or get readings. We found that
the motor controls needed to be in a separate loop. This caused another problem. The
charge control is part of the motor controls but needs values of the battery current and
voltage. Since the values were in the other loop, LabVIEW only allows that value in that
loop till it is ended. This put an end to a software solution. The only solution that time
would permit was to do this function manually.
DC Sensors
With the turbine and batteries connected, and the turbine coupled to the 3-phase motor
an analog current sensor and the two current transducers were used to measure the
output of the turbine. The DC sensors were connected to the DAQ and the
measurements were verified in LabVIEW. When the analog sensor and LabVIEW
values were compared, we found them to be close enough for peace of mind.
RPM Sensor
The hardware and software design of the RPM sensor were first tested separately, and
then as one system. The hardware was tested using an oscilloscope and multimeter to
test the output of the receiver when reflective surfaces were passed in front of the LEDs.
The software was tested by connecting the DAQ to a signal generator set at various
frequencies and verifying the results within LabVIEW. This is where problems were
discovered concerning the readability of the display. These problems occur due to the
method used when calculating a frequency from a binary counter. There is a spike in
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calculated frequency when the elapsed time used for calculation is reset, as well as
variations between iterations in the counter. These problems were addressed within the
software resulting in a much smoother display.
Complete System
After each portion was completed separately, everything was assembled and tested as a
whole. Most of the bugs that came up dealt with the interface within LabVIEW. When
the separate portions were joined together changes had to be made to ensure they did
not interfere with each other. These dealt mostly with loop placement in the block
diagram and separating the power supply control from the sensor measurements.
We then proceeded to test the voltage and frequency inputs to the power supply and
the resulting power output and RPM of the turbine.
Power vs. Speed
Our team thought it would be useful to test the turbines full range of use. A Power vs
Wind Speed curve was given to us by the manufacturer, and we wished to see how they
matched up. We also needed to check what settings for the drive motor were needed
for specific power output. Below are a comparison between the provided power curve
and the one we made through testing.
400
350
Power (Watts)
300
250
200
150
100
50
0
0
500
1000
1500
2000
Speed (RPM)
Measured Curve
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Supplied Curve
It is important to note that there might not be a linear relation between wind speed and
the RPM of the turbine. This can only be tested by attaching the blades to turbine,
installing it outside, and measuring RPM and wind speed simultaneously.
Conclusion
In the beginning of this project, we had very high hopes. There were a lot of different
aspects we hoped to expand upon from the previous group, and a lot of interesting
ideas we wanted to implement. Unfortunately, due to the budget constraints halting
the installation of the turbine outside, and the loss of much of the previous teams work,
many of these ideas were not realized. However, we are happy that we have provided
a more professional and useable test-bed for the turbine, as well as a RPM sensor that
may be used for a plethora of different projects in the future. Our only shortcoming
that we expected to deliver upon was the full utilization of available wind power.
Throughout this semester, many different solutions for this problem were brought up,
but each of them failed to accomplish what we wanted. The final idea of simulating
pitch control through the software interface is one that we are confident will work, but
bugs in the design of the control as well as time constraints on designing and testing it
have made it impossible to complete. All of this being said, our group wishes to thank
Zhongjian Kang, Lee Harker, and Dr. Ajjarapu for all their help and support throughout
the project.
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Operation Manual
492 Project Title: Wind Turbine System Design and Integration
Team: Brandon Janssen, Luke Lehman, Kenneth Thelen, Hassan Burawi, Elsammani
Ahmed
Advisor: Dr. Ajjarapu
Author: Stephen Copeland
Objective:
The high-level objective of this project is to implement a way of producing
energy from a renewable wind source which can then be integrated into the Iowa State
University power grid. This will be achieved by adding various sensors and a user
interface so that the energy being produced can be monitored accurately.
Functional Requirements:

Turbine will output a DC voltage of 24VDC

Turbine’s output is 400W

Inverter supplies AC power to a load

Sensors are connected to a data acquisition device (DAQ), and displayed on a
LabVIEW interface

Wind power is simulated with a motor coupled with the turbine

An adjustable power supply is used to vary motor’s input to turbine
Implementation:
So far the implementation of the wind turbine system includes an adjustable
power supply, ac motor, coupling to the turbine and motor, DC voltage and current
sensors, an RPM sensor, a GPIB –USB connector, USB NI DAQ connector for interfacing
with Labview software, a battery bank, outback inverter, and AC load in the form of
four light bulbs. The ac motor is attached to the turbine in order to produce the needed
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energy to power the light bulbs after the signal is passed through the outback inverter.
As the energy is being transferred from the motor to the load, DC voltage and current
sensors along with the RPM sensor placed next to the coupling ensure that the signal is
not going to harm any of the connected components. Labview is used to obtain the
reading from the various sensors in order to act as a user interface which allows an
operator to optimize power production from the turbine itself.
Setup:

Couple AC motor and turbine on an adjustable table so that proper leveling of
the connection is possible

Wrap the coupling with electrical tape leaving a small portion visible to reflect
light to the RPM sensor

Position the RPM sensor next to the coupling

Connect the turbine to a stop switch in parallel

Connect a current sensor in series with the stop switch

Connect a 2 x 12V battery bank in series

Connect a current sensor in series with the positive terminal of the battery bank

Connect a voltage sensor (voltage divider with 100K ohms and 390K ohms) in
parallel with the battery bank

Connect DAQ USB across 100K ohm resistor

Connect an outback inverter in parallel with the voltage sensor

Connect a switch between the voltage sensor and the positive terminal of the
inverter

Connect the load (light bulbs) to the inverter

Connect RPM sensor to a 5V DC power supply

Connect 15V DC power supplies to current sensors

Connect power supply to 220V plug-in on wall

Plug DAQ-USB and GPIB-USB into the computer

Turn on power supply

Open Labview interface
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
Assign the proper address to the GPIB as 1

Ensure that output of the power supply is off

Adjust voltage and frequency of power supply using the LabVIEW interface
until desired RPM or power output is reached
Testing Observed:
During the time that I was able to spend with the design team I was unable to
observe any successful testing due to an issue with the computers within the lab.
However, the group assures me that they have successfully carried out tests during
which the system was able to generate the power required to turn a load of four light
bulbs on.
Critique:
Strengths:


The system is able to transmit power from the generator to the load.
The sensors allow for ease of control over the entire system.
Weaknesses:

Not able to implement system in real world conditions.
While the system is not able to be placed on the roof of Coover, it has still met all
of the requirements according to the group. Through the use of the various sensors and
interfaces they have achieved a reliable user interface, the coupling of the motor and
turbine has been successfully implemented, and through the adjustment of a power
supply the system is capable of supplying power to an AC load. Plan for further
research on the system include the use of the designed interface and to simulate varying
wind speeds over time to better understand its effect on the a load.
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Appendix
LEM LA 55-P Current Transducer
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NI 6008 USB
Specifications:






8 analog inputs (12-bit, 10 kS/s)
2 analog outputs (12-bit, 150 S/s); 12 digital I/O; 32-bit counter
Bus-powered for high mobility; built-in signal connectivity
OEM version available
Compatible with LabVIEW, LabWindows/CVI, and Measurement Studio for
Visual Studio .NET
NI-DAQmx driver software and NI LabVIEW SignalExpress LE interactive datalogging software
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Outback GTFX2524 Inverter
Nominal DC Input
24 VDC
Continuous Power Rating
2500 VA
AC Voltage/Frequency
120 VAC 60 Hz
Continuous AC RMS Output
20.8 Amps AC
Idle Power
6-20 Watts
Typical Efficiency
92%
Total Harmonic Distortion
2-5%
Output Voltage Regulation
± 2%
Maximum Output Voltage
50 amps AC RMS
AC Overload Capability
Surge
6000 VA
5 seconds
4800 VA
30 minutes
3200 VA
AC Input Current Max
60 amps AC
AC Input Voltage/Frequency
80-150 VAC 58-62 Hz
DC Input Range
21-34 VDC
Weight
56 lbs
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Southwest Windpower Air X 400
Rotor Diameter
46 in.
Weight
13 lb
Start-Up Wind Speed
8 mph
Voltage
24 VDC
Rated Power
400 watts at 28 mph
Turbine controller
Micro-processor based smart internal regulator
Body
Cast aluminum
Blades
3-Carbon fiber composite
Overspeed Protection
Electronic torque control
Kilowatt Hours/Month
38 kWh/mo at 12 mph
Survival Wind Speed
110 mph
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Display Load Setup
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