Download A Proposal to Interface the Avista SR

Hydrogen Fuel Cell and Flywheel Interfacing with AMPS
March 11, 2005
Group 1 (Fuel Cell)
Group 2 (Flywheel)
Adam Lint
[email protected]
Gavin Abo
[email protected]
Chris Cockrell
[email protected]
Nate Stout
[email protected]
Daniel Hubbard
[email protected]
Nathan Thomas
[email protected]
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A Proposal to Interface the Avista SR-12 PEM
Hydrogen Fuel Cell to the Analog Model Power System.
1. Abstract
Electrical Engineering students are in need of a method to test and explore alternative energy
sources such as Proton Exchange Membrane (PEM) fuel cells. The University of Idaho has
acquired an Avista SR-12 500 Watt fuel cell. It is desired that this fuel cell be interfaced with
the existing Analog Model Power System (AMPS) located in the basement of the Buchanan
Engineering Laboratory. Accomplishing this would require voltage regulation for the output of
the fuel cell and conversion of this DC voltage to three phase AC voltage. In addition, control
algorithms must be designed to monitor power levels and provide a graphical interface from
which students can gather data. This interfacing process will require careful design and must
meet the specifications outlined in this report.
2. Background
2.1 Significance of the Project
In the mid 1990’s, the University of Idaho acquired the Analog Model Power System (AMPS)
from Idaho Power [1]. The AMPS is located in the basement of the Buchanan Engineering
Laboratory on the university’s campus in Moscow, Idaho. The purpose of the AMPS is to
provide insight into the workings of a power transmission and distribution system. The main
source of power is from the utility (Avista), and currently a generator is interfaced with the
AMPS to provide additional power to the system when needed. In addition to the generator, the
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UI has obtained an Avista SR-12 500W fuel cell from Genesis Fueltech [2]. This fuel cell
represents one of many alternative energy sources available in the 21st century, so it would be a
valuable learning tool if students were able to model it as an energy source on the AMPS. For
this reason, our Senior Design team has decided to complete the task of interfacing the fuel cell
to the model power system.
2.2 The Need for the Interface Design (why can’t we just hook it up?)
Because the fuel cell has a DC output that ranges from 23-43 volts DC [2], a design must be
implemented that would make it compatible with the model power system. In order for the fuel
cell’s output to be useful for providing power to the model power system, it must first be
regulated and then inverted to a three-phase 120 volt AC output. In addition, to prevent the fuel
cell from consuming power, current must only be allowed to flow out of the fuel cell. Lastly, the
implemented design must ensure that the maximum load attached to the fuel cell does not draw
more current than what the fuel cell is capable of providing.
2.3 The Importance of the Interface Design (The theory behind the need)
Interfacing the fuel cell with the model power system is an important and necessary process.
Much care will need to be exercised in the design of the interface components to ensure a safe,
efficient, and useful design. Conservation of energy within DC to DC converters is important
because of the constraints on the input and the specific output requirements [3]. In addition,
special care must be exercised to make sure current is not allowed to flow into the fuel cell. This
would damage the cells and lead to expensive repairs or replacement of parts. Users of the fuel
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cell will also need to be able to take accurate measurements to ensure that proper power flow is
being obtained.
2.4 Accomplishing the Interface Design
In order to provide a steady DC output from the fuel cell, a DC to DC converter must be
designed. This converter will need to be capable of handling a wide range of input voltages.
After a steady DC output is obtained, this signal must be inverted to 120V 3-phase AC pure-sine
voltage. Inverting this voltage will require a pure-sine power converter capable of handling the
maximum power available from the fuel cell. Controls that display the output voltage and other
desired data must be implemented using a microprocessor.
3. Problem Statement
An alternative source of energy is desired for power output to the AMPS. The Avista SR-12
500W fuel cell has been chosen for this task. The fuel cell will be interfaced with the AMPS to
provide power flow into the system. Future ECE students should be able to use this alternative
energy source for educational and research purposes involving power transmission and
distribution.
4. Objectives
The objective is to interface an Avista SR-12 hydrogen fuel cell with the University of Idaho
ECE department’s Analog Model Power System (AMPS) in a manner that will enable students to
explore and modify our design. Our team will create a three-phase AC voltage from the DC
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output of the fuel cell and input this AC voltage into the AMPS. In addition, a graphical
interface will be included for researching and experimenting with the design.
5. Scope
This project will be limited to providing power to the AMPS and providing a graphical user
interface for providing measured data. Power quality and capacity will not be explored in this
project. Protection circuitry is important to protect the fuel cell from surges on the system. The
pre-manufactured hardware used for interfacing will contain built-in protection circuitry, thus
additional protection is out of the scope of this project.
6. Methods
6.1. Regulating the fuel cell output voltage
The DC voltage from the fuel cell varies from 23V to 43V. For this reason, it needs to be
regulated to a steady 12V. This will be accomplished by constructing a DC to DC Buck
converter. Alternatively, a Buck-Boost converter could replace the Buck converter making it
possible to obtain a 24V output. Either converter will need to accept a wide range of input
voltages and output a steady signal with no more than  1V error. These converters should be
able to handle 500 Watts peak power.
6.2. Inverting the DC signal
The regulated DC signal needs to be transformed to a 120V 3-phase AC signal. This will be
accomplished by purchasing a 3-phase sine wave AC inverter. An alternative method would be
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to purchase a single-phase inverter and a phase converter. Either inverter should be rated at
500W peak power input.
6.3. Interfacing
Once the regulator and inverter have been separately constructed, they will need to be interfaced
to the fuel cell, to each other, and to the model power system. This will require that the working
prototype for the DC to DC converter be transferred to a printed circuit board and mounted on a
panel to be interfaced to the inverter in an neat and organized fashion. This panel will then be
used to fully interface the fuel cell to the model power system.
6.4. Graphical Interface
To provide useful information for ECE students performing experiments a microcontroller will
be programmed to display power output and voltage levels to an LCD display. Special circuitry
will be constructed to accurately perform these measurements.
7. Time Schedule
Project Schedule
Design Proposal
Project Briefing
Finalize Initial Design
Demonstrate a Working Prototype
Project Report and Notebook
Revise Voltage Control System
Finalize Protection Circuitry
Complete Interfacing to AMPS
Final Product Demonstration/Release
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Due Date
3/1/2005
3/7/2005
3/14/2005
4/25/2005
5/9/2005
10/1/2005
11/15/2005
11/30/2005
12/9/2005
8. Budget
Item
Printed Circuit Boards
DC/DC Converter
DC/AC Converter
Microcontroller
Compiler
Services
Manhours (Labor costs):
Other Equipment:
Hydrogen
Design Poster/Report Binding
Estimated Costs
$450
$50
$300
$250
$250
$200
???
$500
Total
$2,000
9. Conclusion
Upon completion of this project, Electrical Engineering students will have a valuable tool at their
disposal. These students will be able to research and experiment with a new form of energy
generation. With the fuel cell interfaced as a power source, this project will also enhance the
capabilities of the model power system. In addition, new findings will be thoroughly
documented and explained in order to further improve and enhance understanding of the fuel cell
and the AMPS. Further enhancement and addition of features will be left up to future students
since only the basic functions of the system are feasible for the short amount of time our group
will be spending on this project. This however, will inspire new ideas for future senior design
projects and will ensure that the AMPS remains a useful and dynamic research tool for the ECE
department.
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10. Personnel and Credentials
Adam Lint, ECE Student, Power Engineering Emphasis, University of Idaho.
Coursework includes the following: Circuits I, II; Electronics I, II; Digital Logic;
Microcontrollers; Energy Systems I,II; Engineering Statics/Dynamics/Fluid Mechanics; Signals
and Systems I, II; Electromagnetics; Power Electronics.
Chris Cockrell, ECE Student, University of Idaho.
Coursework includes the following: Circuits I, II; Electronics I; Digital Logic; Microcontrollers;
Energy Systems I,II; Engineering Statics/Dynamics/Thermodynamics; Signals and Systems I, II;
VLSI Design; Information and Coding Theory.
Dan Hubbard, ECE Student, Digital/Analog Electronics Design Emphasis, University of Idaho.
Coursework includes the following: Circuits I, II; Electronics I, II; Digital Logic;
Microcontrollers; Energy Systems I; Engineering Statics/Dynamics; Signals and Systems I;
VLSI Design; Digital Systems Engineering; Electromagnetics.
11. Supporting Research Materials
[1]
User’s Guide for the UI Analog Model Power System. (2002). Moscow, ID: University
of Idaho ECE Department.
[2]
Fletcher, Nathan J. (2004). Avista SR-12 PEM Hydrogen Fuel Cell, Moscow, ID 2004.
Moscow, ID: University of Idaho ECE Department.
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[3]
Bruemmer, Joel E., Williams, Fitch R., & Schmitz, Gregory V. Efficient Design in a DC
to DC Converter Unit, Cleveland, OH, 2002 (Project Report E-13499). Cleveland, OH:
National Aeronautics and Space Administration John H. Glenn Research Center at Lewis
Field.
Addition Material for possible incorporation into the time schedule:
regulator (working prototype): April 15
inverter (working prototype): April 15
interfacing:
regulator to inverter: 4/20
prototypes to fuel cell (for demonstration and testing) 4/25
graphical interface: 10/1
prototypes to final designs: 11/15
mount on panel: 11/15
full interface: 11/30/05
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