Design Solutions
IPFW Electric Vehicle
Sponsored by: National Science Foundation
Advisors: Abdullah Eroglu, Hosni Abu-Mulaweh, Hossein Oloomi
Team Members: Mitchell Eilerman, Leandra Lee, Charles McIntosh, Josh
Weaver, Andres Cobos, Austin Swihart
March 19, 2015
Project Overview

Electrically powered vehicle with solar recharge

Uses data and equipment from previous senior design projects

Bipolar DC-DC converter with four quadrant topology

Solar Panel

Mini-Baja frame
Project Overview

Project’s Final Goals:

Reach speed of 10 mph in 15 seconds time

Achieve Driver Controlled Speed

Design Cooling System

Provide information display

Stay within $1000 budget
Project Diagram
Battery
Arduino
Solar
Panel
Battery
Motor
Heat
Dissipation
Transmission
DC-DC
Converter
Subsystems

DC-DC Converter

Control System

Cooling System

Charging System
DC-DC Converter Concepts

Decoupling capacitors

Decoupling capacitors and shielding

Decoupling capacitors, shielding, separate Arduino from MOSFET drivers,
and reduce the length of the wires
Concept 1: Decoupling capacitors
Advantages:
 Drastically reduces switching noise

Relatively simple design
Disadvantages:
 Consume more space
 High Cost
+24 V
+15 V
+15V
Converter
+9 V
+9V
Converter
+5 V
+5V
Converter
Concept 2: Decoupling capacitors & shielding
Advantages:

Least expensive solution

No relocation of components
Wires
Disadvantages:

Consumes space

System more unwieldy
Arduino
microcontroller
Concept 3: Decoupling capacitors, shielding, separate
Arduino from MOSFET drivers, and reduce the length of the
wires
Advantages:

Less affected by interference from MOSFET drivers

May be placed closer to any needed sensors
MOSFET drivers
Disadvantages:

There may not be space

Longer wires cause additional power loss

Longer wires introduce additional noise
Arduino
microcontroller
Control System Concepts

Pedal press linear with speed

Pedal press linear with voltage

Two-state system: acceleration and constant speed
Concept 1:Pedal press linear with speed
Advantages:

More accurate control of speed

Pedal scheme relatively easy to learn
Disadvantages:

Significant testing required
Concept 2: Pedal press linear with voltage
Advantages:

Control code already designed for application
Disadvantages:

Harder for driver to control vehicle speed
Concept 3: Two-state system:
Acceleration and constant speed
Advantages:

Accelerates at set rate

Easier to maintain speed
Disadvantages:

Cannot directly control acceleration

Steep learning curve
Cooling system

Forced convection by use of fans

Radiator with a water jacket

Fin and fan combination
Concept 1: Forced convection by use of fans
Advantages:

Simple and easily implemented

Reliable, low maintenance and inexpensive

Can affect a large area of components

Free convection changed to forced convection

Can remove variable amount of heat
Disadvantages:

Relies on the ambient air
Concept 2: Radiator with a water jacket
Advantages:

High capacity for heat removal

More easily controlled
Disadvantages:

Components will require a partial disassembly to maintain

Potential safety issues

Requires large amount of energy from batteries

More complicated and more maintenance
Concept 3: Fin and Fan combination
Advantages:

Low maintenance

Localized heat removal

Low cost
Disadvantages:

Relies on ambient air temperature
Charging System Concepts

Use existing 48V booster

Replace booster with 24V booster

Include AC option with either of the previous ideas
Concept 1: Use Existing 48V booster
Advantages:

No additional purchasing of parts

Allows batteries to reach peak voltage
Disadvantages:

The charge time of the batteries will be increased

Power will be lost

System is dependent on light available
Concept 2: Replace booster with 24V booster
Advantages:

Higher efficiency

Charges the batteries faster
Disadvantages:

Purchase of a new booster is necessary

System is dependent on light available
Concept 3: Include AC option with either
of the previous ideas
Advantages:

Charges more quickly if an AC power source available.

Can be charged without light source.
Disadvantages:

No longer solely dependent on solar energy

Control system must be developed

Additional space is needed for the system
Cross’s Matrix - DC-DC Converter
Co
st
Ea
se
Si of D
ze
es
ig
n
Sa
fe
t
Re y
li a
bi
lit
y
DC-DC Converter
Cost
x
9
1
9
9
Ease of Design
1
x
1
9
9
Size
9
9
x
9
9
Safety
Reliability
1
1
1
x
1
1
1
1
9
x
0.12 0.20 0.04 0.36 0.28
Cross’s Matrix - Control System
Ea
se
Sa of D
fe
e
ty si g
n
M
ai
nt
Re ena
li a nc
bi e
lit
y
Control System
Ease of Design x
9
9
9
Safety
1
x
1
4
Maintenance
1
9
x
9
Reliability
1
4
1
x
0.05 0.38 0.19 0.38
Cross’s Matrix - Cooling System
Co
st
Ea
se
Ae of D
st
e
he si g
Si
n
z e ti cs
W
ei
gh
Sa t
fe
t
M y
ai
nt
Re ena
li a nc
bi e
lit
y
Cooling System
x
9
1
1
9
9
4
9
Ease of Design 1
x
1
1
4
9
1
9
Aesthetics 9
9
x
9
9
9
9
9
Size 9
Weight 1
9
1
x
9
9
9
9
4
1
1
x
9
1
9
Safety 1
1
1
1
1
x
1
1
Maintenance 4
9
1
1
9
9
x
9
Reliability 1
1
1
1
1
9
1
x
Cost
0.09 0.15 0.03 0.05 0.15 0.23 0.09 0.20
Cross’s Matrix - Charging System
Co
st
Ea
se
Sa of D
fe
e
ty si g
n
M
ai
nt
Re ena
li a nc
bi e
lit
y
Charging System
Cost
x
9
4
9
9
Ease of Design
1
x
4
4
9
Safety
4
4
x
1
4
Maintenance
Reliability
1
4
9
x
9
1
1
4
1
x
0.08 0.20 0.23 0.16 0.34
Design Decisions
Engineer
Decision
Factors
ne
a
Li r w
ne /
S
a
Ac r w pe e
ce / V d
l.
o
Pr lta
of ge
ile
Control System
Li
Decision
Factors
De
co
Sh upl
ie ing
l
Di d in Ca
pa
st g
an
ci
to
ce
rs
Ar
du
in
o
DC-DC Converter
Engineer
Andres 3.6
3.3
3.1
Andres 2.8
3.3
3.1
Charles 2.7
3.3
3.3
Austin 3.0
3.0
2.0
Mitch 3.4
3.0
2.6
Charles 2.8
3.6
2.6
Leandra 3.1
2.3
3.2
Mitch 2.4
Josh 3.0
3.2
3.0
3.6
3.3
Weighted Scores
3.23 3.20 3.00
Weighted Scores
2.85 3.17 2.87
Design Decisions (cont.)
Decision
Factors
Engineer
Ex
i
Fi
n
s
Fa & F
ns an
s
W
at
er
Ja
ck
et
Decision
Factors
Charging System
st
24 ing
V 48
Op Bo V B
tio ost oo
st
na er
er
lA
C
So
ur
ce
Cooling System
Engineer
Austin 2.9
2.5
2.9
Andres 3.6
3.5
2.4
Leandra 3.8
3.2
2.5
Charles 3.0
2.7
3.2
Josh 2.9
2.7
2.8
Mitch 3.3
3.0
3.2
Weighted Scores
3.20 2.80 2.73
Weighted Scores
3.31 3.08 2.92
Final Design Decision
Primary Concept
Secondary Concept
Control System
Pedal press linear with voltage
Pedal press linear with speed
DC-DC Converter
Decoupling Capacitors between sources
Shielding wires leading to Arduino
Cooling System
Fins and fans
Water jacket
Charging System
48 V booster
24 V booster
Questions?