Project Proposal
Hardware-in-the-Loop Testbed
ECE 4901 – Senior Design I
Fall 2013
ECE Project Members:
Ken Gobin
Aaron Eaddy
Douglas Pence
Faculty Advisor: Sung Yeul Park
Summary:
This project is aimed at developing a proof-of-concept multifunctional diagnostic testbed
for potential use in batteries, fuel cells and electronic energy storage devices. This testbed will
allow dynamic diagnostic monitoring through a digital interface with a microcontroller. A
sensor circuit will relay useful diagnostic data related to the electronic storage device being
monitored to a computer where the data can be read and analyzed with ease. The original
concept will be built around the charging and simultaneous testing of one battery, but will have
the capabilities to be expanded in the future for multiple batteries.
Background:
Batteries are widely used in many power applications such as hybrid/electric vehicles and
mobile electronics. Many of these power applications have become an integral part of society
and in some cases are necessities to carry out daily routines. Societies dependence on these
devices really boils down to societies dependence on batteries.
A battery is an energy storage device. A battery consists of electrochemical cells that
have the ability to store and convert chemical energy into electrical energy. There are many
different types of batteries some of which are single-use and others which can be reused by recharging them. Most of the electronic devices and vehicles that are used today use rechargeable
batteries. Even though these batteries can be used multiple times they eventually loose their
usefulness.
Our design project will focus on monitoring the battery during it’s charging. With this
proof-of-concept design further research can be done to possibly improve batteries and their
lifespan.
The task at hand is to create a hardware-in-the-loop testbed that will be able to monitor
the battery’s state of health, state of charge, remaining useful life, voltage, current, and
temperature. The monitoring system will focus on one battery to start, but will have expansion
capabilities.
Requirements:
The output of our design will be the battery’s voltage, current, temperature, state of
health, state of charge, and remaining useful life. To obtain these we will use the setup outlined
below:
The system composes of the following:




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Battery charger
Microcontroller
o Matlab/Simulink Embedded coder
Sensor circuit
Battery
Computer
Battery Charger
A previous senior design team designed the battery charger that we will be using. In their
design a 12V lead acid battery was used. The battery charging systems works using a solar panel
as the input. The solar panel voltage is rated to be 24 - 48V. They used a buck converter to step
down the voltage to meet the requirement of a 12V output for the battery.
The battery charger has multiple stages for the charging algorithm. In the first stage a
small amount of constant current is used to initiate the charging on the battery, the battery is
assumed to be fully depleted to begin with. When there is enough charge the battery is then
supplied with a higher amount of constant current. The next stage is the over voltage stage where
a constant voltage of approximately 14.6V is supplied to the battery. Once the current of the
battery drops there is a constant voltage supplied at 12.5V to maintain a fully charge battery and
prevent any discharge.
For our use we will be removing the solar panel input and using a power supply. Below is a flow
chart of the battery charger we will be using.
Microcontroller
For this project, we will be using the Texas Instruments DSP F28335 flash memory
capable microcontroller. This microcontroller has the capability for six (6) separate data/address
lines, up to 59 general purpose inputs/outputs and analog to digital conversion. The flash
memory capable version is important so that we may consistently re-write our model coding onto
the microchip as needed during the design process without compromising on flexibility and
efficiency. To implement the coding changes, we will be interfacing with the microcontroller
through a USB connection from a computer. On the computer we will be using MATLAB,
Simulink and Code Composer Studio as the software processing and interface. These programs
will allow us to implement any design requirements we choose.
Sensor Circuit
For this project, the most important part of the battery charger is the sensing circuit.
Currently, it is only capable of sensing voltage and current from one battery at a time, but our
work looks to make the current system expandable to accommodate multiple cells. The voltage
sensing circuit uses a voltage divider to measure a voltage manageable for the ADC. Then it is
fed through an Op-amp because the ADC needs the signal to be amplified on the way in. The
current sensor uses a chip ammeter to read the current on the output of the battery, also using an
Op-Amp to amplify the current coming out of the sensing circuit into the ADC. Capacitors are
placed strategically throughout the circuits to eradicate any signal noise caused by external
sources. Temperature is an important measurement that needs to be made, and the existing circuit
has ambient temperature sensing capabilities. We are looking to expand upon that capability and
add surface mounting thermistors to the charger so we can read the temperature at the surface of
the battery while it is charging. There are both an input group of sensors and an output pair of
sensors to measure both the current and voltage coming into the sensing circuit from the source,
and leaving out of the battery charger.
Project phases, timing, and milestones:
Oct
Nov
Dec
Research Item
Jan
3
4
1
2
Schematics + Part List
PCB Layout
Prototype Design
Parts Order
PCB Order
Board Assembly
Hardware
Functions
Board Testing
Algorithm
Power Test
Revision
Budget:
Total Budget
$1,000
Current Expenditure Estimate
 TI F28335 DSP
 Sensing Circuit
 Miscellaneous
-$129.36
-$350.00
-$50.00
Budget Surplus Estimate
$470.64
3
4
1
Feb
Mar
Apr
Project collaborators:
Aaron Eaddy
Team Member
aaron.eaddy@uconn.edu
Ken Gobin
Team Member
ken.gobin@uconn.edu
Douglas Pence
Team Member
Douglas.pence@uconn.edu
Sung Yeul Park
Team Advisor/Sponsor
supark@engr.uconn.edu