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University of Portland
School of Engineering
5000 N. Willamette Blvd.
Portland, OR 97203-5798
Phone 503 943 7314
Fax 503 943 7316
Functional Specifications
Project Surf Scoter: Fluorescent
Lamp Electronic Ballast
Contributors:
McGuire, Lance
Nelson, Sam
Ortiz, Sam
Stone, Jordan
Approvals
Name
√
Dr. Ward
Mr. Fant
Date
Name
√
Date
Dr. Hoffbeck
Insert checkmark (√) next to name when approved.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
FUNCTIONAL SPECIFICATIONS
PROJECT SURF SCOTER
REV. 1.0
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Revision History
Rev.
0.9
0.95
0.96
1.0
Date
09/21/07
09/28/07
10/03/07
10/05/07
UNIVERSITY OF PORTLAND
Author
J. Stone
J. Stone
L. McGuire
J. Stone
Reason for Changes
Initial draft
Second draft
Third draft
Final Revision
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CONTACT: J. STONE
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Table of Contents
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Summary.......................................................................................................................
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Introduction ..................................................................................................................
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PROJECT SURF SCOTER
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Background .................................................................................................................. 3
Requirements ............................................................................................................... 4
Overview ..................................................................................................................................................4
Physical Specifications............................................................................................................................4
General .............................................................................................................................................4
Design Structure...............................................................................................................................5
Weight ...............................................................................................................................................5
Wiring ................................................................................................................................................5
Dimensions .......................................................................................................................................5
Environmental Specifications .................................................................................................................5
General .............................................................................................................................................5
Temperature .....................................................................................................................................5
Relative Humidity .............................................................................................................................6
Altitude ..............................................................................................................................................6
Hardware Specifications .........................................................................................................................6
System Hardware ............................................................................................................................6
Power Supply ............................................................................................................................6
Peripheral Devices ....................................................................................................................6
Cables........................................................................................................................................7
Output Power ............................................................................................................................7
Circuit Board ..............................................................................................................................7
Board Hardware ...............................................................................................................................7
EMI Filter ...................................................................................................................................7
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Rectifier......................................................................................................................................7
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PFC ............................................................................................................................................7
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Inverter .......................................................................................................................................
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FUNCTIONAL SPECIFICATIONS
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Microcontroller ...........................................................................................................................8
Conclusions ................................................................................................................. 9
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CONTACT: J. STONE
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List of Figures.
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Figure 1. Block Diagram of.Surf Scoter Product...........................................................................................3
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FUNCTIONAL SPECIFICATIONS
PROJECT SURF SCOTER
UNIVERSITY OF PORTLAND
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List of Tables .
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Table 1. Physical Specifications
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Table 2. Environmental Specifications
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Table 3. System Hardware Specifications ....................................................................................................6
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
FUNCTIONAL SPECIFICATIONS
PROJECT SURF SCOTER
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Summary
The goal of Surf Scoter is to design and build an electronic ballast for a fluorescent tube
light. Fluorescent lights are much more efficient than traditional incandescent lights, as
they consume about ten times less power. Incandescent lights waste energy by
converting more of their consumed power into heat, while fluorescents achieve higher
efficiency by converting a greater percentage of consumed power into light.
The challenge concerning a fluorescent tube lamps is the higher voltage and frequency
required to achieve high efficiency. While incandescent bulbs operate at a standard
residential voltage and frequency of 120V and 60Hz, respectively, fluorescent lights
operating at maximum efficiency require voltages between 200 and 300V and frequencies
ranging in the tens of kHz. An electronic ballast must be used to regulate the electricity
delivered to the lamp because of these constraints.
A ballast is a device that controls the voltage, current and optionally frequency of power
driving a lamp. An electronic ballast uses solid-state electronic circuitry to achieve the
necessary conditions.
This document is a functional specification of an electronic ballast. It provides numerical
goals for parameters of the project and a basic outline of the components of which the
ballast circuit will consist.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
FUNCTIONAL SPECIFICATIONS
PROJECT SURF SCOTER
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Introduction
This document is intended for the faculty and senior Electrical Engineering students of the
School of Engineering at the University of Portland, as well as the industry representative
overseeing this project. A general introduction to fluorescent lamps and electronic ballasts
is first presented in this document, followed by a detailed description of the functionality of
the electronic ballast which will be designed and built. The basic blocks of circuitry that will
be required are also outlined.
Not contained in this document are the details of the circuitry or the connections to be
made between the components of this product, as these elements have not yet been
designed. In some areas, however, possible options for circuit design are given.
The rest of this document contains a background of fluorescent lamps and electronic
ballasts, an overview and the physical, environmental, hardware and software
specifications of the project. This document ends with a conclusion.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
FUNCTIONAL SPECIFICATIONS
PROJECT SURF SCOTER
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Background
An electronic ballast is an apparatus that controls the current flow into a circuit. In this
case, the circuit is a fluorescent lamp. There are various types of ballasts, but the
electronic ballast increases the input frequency (typically 60 Hz in the United States) to a
much higher frequency in the range of 10 to 40 kHz. Not only does this eliminate the
flickering that is typical of fluorescent lighting but also increases the efficiency of the lamp.
An electronic ballast can be as simple as a resistor and inductor, but the ballast that will be
used here will be made of more complicated solid-state devices.
The type of electronic ballast that will be used works by increasing the frequency and
amplitude of the input voltage for the initial ionization of the gas within the lamp. Once the
arc inside the lamp is started, the amplitude of the input voltage is decreased to a nonzero constant value to maintain the arc.
The electronic circuitry that will be used can be broken up into several functional blocks, as
shown in Figure 1. First, the standard 120V, 60Hz line power will enter an
electromagnetic interference filter. A rectifier then converts the AC signal into DC and a
Power Factor Correction (PFC) element will eliminate any reactive power consumption
introduced by the circuit or lamp. Next, an inverter will convert the DC power into AC
power of the desired voltage, current and frequency to operate the lamp. This inverter will
be controlled by a microcontroller to achieve the desired output power.
The circuitry in this product will be contained in a case incorporating a safety-switch so that
the input voltage cannot be applied unless the case is closed, making the circuitry
inaccessible to any humans. The fluorescent lamp itself will also be encased so that
particles or chemicals will not cause harm should the circuit or tube malfunction during
testing.
Fuse
EMI Filter
Rectifier/PFC
Inverter
Lamp
120V, 60Hz
Microcontroller
Figure 1. Block Diagram of Surf Scoter Product
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
FUNCTIONAL SPECIFICATIONS
PROJECT SURF SCOTER
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Requirements
Overview
This product converts single phase, 120V, 60Hz electricity into a signal that can be used to
power a fluorescent lamp. Any electricity customer, whether illuminating their residence or
business, will benefit from the high efficiency of fluorescent lights, but will require additional
components (such as this ballast) for these lights to achieve a high level of efficiency.
Power from a 120V, 60Hz, single phase line will enter the circuitry of this product. After
passing through the ballast, power will be at a frequency of approximately 20kHz and a
voltage between 200 and 300V, depending on the performance of the lamp. Internally,
this product will contain solid-state electronic circuitry and a microcontroller. The functional
blocks of this circuitry is shown in Figure 1 and discussed in the “Hardware” section of this
chapter.
Physical Specifications
Table 1 contains a list of the physical specifications and their required values.
Table 1. Physical Specifications
Requirement
Value
Design Structure
Plexiglass box
Weight
Wiring
<10 lb. (ballast only)
Leads color coded to
ANSI standard
Dimensions
5 ft x 1ft x 1 ft
General
The entire project, including lamp and lamp housing, will be enclosed in a Plexiglass box
to ensure that no particle or chemical component of the lamp would injure a person should
the lamp malfunction. Additionally, this container will open and close on a hinge and will
incorporate a safety-switch that will disengage power when the container is opened,
ensuring safety from electrocution.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
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Design Structure
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. for the project will be made of Plexiglass, a transparent substance stronger
The enclosure
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than glass. .It is also impact and electrically resistant to a high degree, in case of an
electrical problem or rupture in the lamp. The casing will also help prevent mercury
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contamination should the lamp break.
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Weight
The electronic ballast itself will weigh no more than ten pounds.
Wiring
The electrical wiring of project Surf Scoter will conform to ANSI standards.
Dimensions
Project Surf Scoter will be contained in a Plexiglass box with a volume of 5ft x 1ft x 1ft.
This includes the ballast, lamp and lamp housing.
Environmental Specifications
Table 2 contains a list of the environmental specifications and their required values.
Table 2. Environmental Specifications
Requirement
General
Value
Temperature
Standard Room
Operation
10-40 degrees C
Relative Humidity
No condensation
Altitude
0-8000 ft.
General
Ballast should be able to operate in a room at standard room temperature with little
condensation from relative humidity.
Temperature
Ballast should withstand standard temperature of 10 to 40 degrees Celsius.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
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Relative Humidity
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. not be required to operate in conditions where there is condensation or
The ballast will
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high relative humidity.
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Altitude
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The circuit should be operable at up to 8000 feet in altitude.
Hardware Specifications
This section covers the power supply and hardware specification for project Surf
Scoter.
The hardware is the nexus of the project. The lamp will only turn on if the hardware is
properly designed and configured. These are the specifications for the hardware that
define the standards used in designing the electronic ballast.
Table 3. System Hardware Specifications
Requirement
Power Supply
Peripheral Devices
Cables
Output Power
Circuit Board
Value
120V @ 60Hz
4’ T8 Lamp
Luminaire
Input power
Output power
Capable of
lighting the lamp
High Quality
System Hardware
Power Supply
The ballast design will require an AC supply of 120V at 60Hz, single phase, as provided
by a standard electrical outlet.
Peripheral Devices
A single fluorescent lamp will be operated by the ballast. The model that will be used is a
four foot T8 lamp, which is commonly used in commercial applications. The lamp will be
supported by a luminaire purchased from a manufacturer or retailer.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
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Cables
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The ballast and lamp will require a cable to deliver the input power from an electrical outlet
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to the circuit and another cable to deliver the output power from the ballast to the lamp.
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Output Power
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The power provided by the ballast will be sufficient to light the lamp used in the project.
This includes the appropriate starting conditions and the conditions necessary for long
term operation of the lamp.
Circuit Board
A high quality circuit board will be used for this project, ideally with the internal ballast
connections being soldered into place. This board will minimize unintended resistances
and capacitances across the circuit.
Board Hardware
The project will use a standard PC (printed circuit) board, single-sided for lowest cost.
EMI Filter
The electromagnetic interference (EMI) filter is used to block ballast-generated noise from
being transmitted back onto the power lines. This filter may be active or passive, and will
be designed according to needs as this project is developed.
Rectifier
The full-wave rectifier converts the AC source to a DC voltage supply. The rectifier for this
project will likely utilize four diodes and a capacitor in a bridge formation. The rectifier will
need to be able to handle the input of 120V at 60Hz and convert it to a steady DC source.
It will also need input and output impedances controlled to not interfere with the overall
operation of the circuit.
PFC
This unit is used to correct for low power factor present in the input power and introduced
by the EMI filter. Depending on the quality of power (ratio of reactive power to real power)
this could involve the use of simple capacitors or more complex elements such as Buck,
Boost, or Buck-Boost converters. Power Factor Correction can be implemented before or
after rectification and whichever order is found to be more efficient will be used.
Inverter
The inverter converts DC to AC at the desired frequency in order to control the voltage
across the fluorescent lamp’s electrodes. This project will utilize solid state circuitry for this
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CONTACT: J. STONE
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component. This element will need to output the necessary voltage and frequency with
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duty cycle controlled by the microcontroller.
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Microcontroller
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. will be used to adjust the output frequency to achieve maximum power
A microcontroller
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PROJECT SURF SCOTER
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efficiency and light output from the lamp. This is done via pulse-width modulation control
of the inverter. The microcontroller will need to be powered via a DC-to-DC converter to
meet the smaller voltages required by the microcontroller.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE
FUNCTIONAL SPECIFICATIONS
PROJECT SURF SCOTER
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Conclusions
This document has covered requirements of the electronic ballast design. It has presented the
physical makeup of the project and also the environment in which it will be expected to perform. This
document also discussed the electronic parts of which the project will be comprised. This document
has presented the requirements that will be achieved in developing this project.
UNIVERSITY OF PORTLAND
SCHOOL OF ENGINEERING
CONTACT: J. STONE