Transcript presentation

Illini Formula Electric Data Acquisition System
Tanmay Adya
Anthony Herwaldt
Neal Sarraf
December 8th, 2015
ECE 445 Fall 2015
Team 7
TA: Zitao Liao
The Team
Tanmay Adya
Anthony
Herwaldt
Neal Sarraf
University of Illinois
University of Illinois
University of Illinois
B.S. Electrical Engineering
B.S. Electrical Engineering
B.S. Electrical Engineering
Hoeft Technology &
Management Program
Specialization in Signal
Processing
Hoeft Technology &
Management Program
Introduction
Illini Formula
Electric Team
The Illini Formula Electric team is a student-run
organization on campus that engineers and
operates a fully electric vehicle.
The Team
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
Team builds vehicle throughout Fall and some of
Spring semesters
Competes in two competitions each year:
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Formula Hybrid – New Hampshire, April / May
Formula Electric – Lincoln, NE, June
The Competition
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The team must design, build, and race an openwheel, single-seat racecar
Special emphasis is put on drive train innovation
as well as fuel efficiency in a high-performance
application
University of
Illinois
The Problem
Availability, yet inaccessibility
of valuable data
Need for live, remote visual
performance monitoring of
vehicle
Desire to improve the team’s
technical and performance
strength in competitions
Objectives
Solution
To create a data
acquisition system that
would be able to
wirelessly transmit
critical operational data
from the car in real time
Data Acquisition
Our goal for the semester was to create a system that would tap into
key data sources, extract the key information, and transmit it to the
team remotely from the car such that it could be utilized effectively.
Battery
Management
System
Speed
Sensing
Engine Torque
and RPM
Other Fault
and Safety
Information
Design Methodology
Define Metrics to be
Found through Sensors
Select / Integrate
Microcontroller
with Sensors
Build a Wireless
Transmission
System
Integrate all
Components of
Design
Original Design
Sensors
No longer
required current
sensor since
data was
available from
BMS
Hall Effect
Hall Effect
sensor module
removed,
velocity info
obtained from
ECU
Processor
Design
Modifications
Eliminated
processing unit
on receiver end,
data read
through serial
terminal
Testing
Basic Requirements
Tolerance Analysis

Successful operation of system relies on
stable power supply and proper current
‒
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‒
Mbed requires 4.5–14 V DC, 11mA
Xbee requires 2.8–3.4 V, 215 mA
CAN Bus requires 3.3 V, 85–100
mA
Technical Need
All in all, this requires a
power supply that can source
5V DC and 3.3V DC with
current load of 1.811A on the
5V and 315mA on the 3.3 V
lines
Buck Converter will need to
source 3.3V, and provide
5+/- .25 VDC and 3.3 +/.25 VDC
Utilize TPS54383 Dual 3-A
converter to convert 12
VDXC on car to 5 VDC and
3.3 VDC
Adequate voltage supply
within threshold of
operation + current to
power all components
Utilize lab equipment to
test threshold value
Use multimeter in parallel
with power supply to
validate voltage range and
add constant current load
Let run for one hour -> if
multimeter is within voltage
range with 2A, test passes
Buck Converter
TPS54383
Chip Description

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Dual output, non-synchronous stepdown buck converters
Capable of supporting 3 A output
applications that operate from a 4.5
to 28V
Output voltage between 0.8 V and
90% of the input voltage
Buck Derivation 1
Inductor
Buck Derivation 1
Inductor Derivation
Data Sheet
fsw = 250kHz
VIN(MAX) = 13.2 V
ILRIP(max) = 30% of 2A output
Dmin = 40.1% min
Equation
𝐿𝑚𝑖𝑛 ≈
VIN(MAX) − VOUT
𝐼𝐿𝑅𝐼𝑃(𝑚𝑎𝑥)
1
∗ 𝐷𝑚𝑖𝑛 ∗
𝑓𝑠𝑤
𝑳𝒎𝒊𝒏 = 21.92 μH ≈
22 μH
Desired Outcome
We desired an output
voltage of 5V
VOUT = 5 [V]
Buck Derivation 2
Schottky Diode
Buck Derivation 2
Inductor Derivation
Data Sheet
Internal compensation has a
resonance of fRES = 3kHz
VIN = 13.2V
Equation
𝐶𝑜𝑢𝑡 ≈
1
4 ∗ π2 ∗ 𝑓𝑅𝐸𝑆
Desired Outcome
2
∗𝐿
V 𝐵𝑅 𝑅 𝑚𝑖𝑛 ≥ 1.2 ∗ 𝑉𝐼𝑁
𝑽 𝑩𝑹 𝑹 𝒎𝒊𝒏 ≥ 𝟏𝟓. 𝟖𝟒 𝑽
20 V breakdown
Keeping in mind that
L = 22 μH
COUT = 128 μF
Buck Derivation 2
Final PCB
Final PCB: Parts
Mbed Microcontroller
ECU MCP2551 CAN Module
BMS MCP2551 CAN Module
Buck Converter
Xbee Transmitter
Final Design
Before: Schematic
After: PCB Layout
Broken Inductor
Requirements &
Verification (1)
Requirement
Verification
Points
1. Engine Control Unit (ECU) CAN bus
module properly interfaces with the ECU
CAN bus.
1. Compare ECU data from the processing unit with
data gathered from IFE’s ECU configuration software
installed on their laptop. Data must match within 5%
error.
15
2. Battery Management System (BMS) CAN
data module properly interfaces with the
BMS CAN bus.
2. Compare the data gathered by the processing unit
from the BMS CAN data connection with the serial
data gathered through IFE’s laptop. Data matches
within 5% error.
15
3. a) Processing unit successfully interacts
with wireless transmitter module and can
transmit serial data.
3. a) Run test program on processing unit that
transmits the serial message “Test” to ensure
message is successfully sent.
30
b) Processing unit can filter incoming data
and send the critical data to the transmitter
module.
b). Monitor the serial terminal on the receiver and
ensure that the streaming data is not scrolling
through at a speed too fast to read.
Requirements &
Verification (2)
Requirement
Verification
Points
4. a) Place a digital multimeter in parallel with the
source and test if it reads 5V +/- 0.25V.
4. Buck Converter power source will supply a
5 +/- 0.25V and source 2 +/- 0 .25A current.
5. a) Transmitter effectively transmits data
more than 70m.
b) Serial data containing car data (engine
temperature, RPM, torque, battery current,
battery voltage, speed, and warnings) can
be successfully sent from transmitter to
receiver within 5% error.
b). Add microcontroller, MCP2551 CAN chips, and
Xbee module as load to power supply and check
output voltage (5V +/- 0.25V) and current levels (2
+/- 0.25A).
10
5. a) Measure a distance of >70m from transmitter
and send simple serial data from transmitter to
receiver. Send a message of ‘Test’ and check that
receiver obtained correct message.
30
b) Cross check data gathered from the processing
unit via USB serial connection with data gathered
from the processing unit via wireless transmitter and
ensure that data matches within 5% error.
Software Diagram
CAN Network
MCP2551 CAN
Transceiver Chip
Description
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Drives CAN interface for
ECU and BMS data
collection
Operates on speeds up to
1 Mb/s
CANH and CANL to CAN
Bus
Digital transmit data (TXD)
and receiver data (RXD) to
microcontroller serial pins
Transceiver Chip Image
Battery Management
System
Description

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Gathers voltage and temperature data from 78 high-discharge batteries, fault information
Monitors current going in and out of battery pack
Transmits this data through CAN bus to mbed
BMS Image Example
[2] Elithion CAN Specs
Sample BMS Data
Engine Control
Unit
Description
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Battery powered AC motor
controller
Gathers many data points on
motor operation and control
Transmits pre-set TPDOs
(Transmit Process Data Objects)
in CANOpen
Current method: physical cable
access from ECU to
configuration laptop
DB-9 serial connection to ECU
CAN Bus
Our method: CAN breakout
board, CANH & CANL to mbed
ECU Image
[1] SKPang Electronics
DB-9 Connector
MCP2551 CAN
Transceiver
Sample ECU Data
Wrong data type/endian format
Wireless Transmitter
& Receiver
 Transmission distance of ~70m
 Serial data transmission
 Xbee wireless transmitter and receiver
 Maximum rated distance: 1 mile
 Baud rate: 9600 bps (default)
 Verified 70m transmission w/ obstacles
 Future work: receiver GUI
Box Design (1)
Design Constraints
1) Overall the design of the box needs to
be designed with a material that is sturdy
but extremely heat resistant
2) The material must be see-through
based on the preference of the IFE team
3) The box must be mounted on a generic
plate so that the plate can be mounted to
the car properly instead of the box
4) Attempt to have connectors attached
to box on the side instead of connecting
the circuitry entirely on the inside of the
box
5) Have the box’s materials and all
connectors weather resistant
Initial High-Level Design
Box Design (2)
Our Box: Different Viewpoints
Key Points
 Ports were made for wires such as CAN High and Low, and the DB9 Connector
and Mini USB and the wireless antenna to transmit data
 Polycarbonate material makes the box sturdy and both heat and water resistant
 Modular-mountable box that can be mounted in multiple locations on the car
Conclusions &
Future Work
Given that our project was successful in many regards, we recognize that there are several
lessons to be learned and areas to improve our deliverable in the future for IFE.
Project Takeaways
Conclusions
Future Work
 Live data is being read from the
Battery Management System and the
Engine Drive
 Graphical User Interface can be
further improved to filter data from
BMS and ED in more simple manner
 The circuit has been integrated with
the car’s design and can be mounted
if needed
 Improved Box Design more fit to the
car’s design and restraints
Sustainable Project for IFE Success
Our team has learned much during the semester and appreciates the generous time,
resources, and consideration in furthering our education and understanding of engineering.
Special Thanks
 Teaching Assistant
 Zitao Liao
 Illini Formula Electric Team
 Matthew Fedderson
 James Butler
 Michael Kabbes
 Senior Design Staff
Questions?
References
 [1] "CAN-Bus Breakout Board." SK Pang Electronics. SK Pang
Electronics. 06 Dec. 2015. <http://skpang.co.uk/catalog/canbusbreakout-board-p-754.html>.
 [2] "Elithion Lithiumate Manual - Controller CAN Specs." Elithion.
Elithion. 06 Dec. 2015. <http://lithiumate.elithion.com/php/
controller_can_specs.php>.