Micro Electric Urban Vehicle

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Micro Electric Urban VehicleTest
PlatformFinal Presentation

• Students
• Kyle Dieter
• Spencer Leeds
• Nate Mills
• Advisors
• Dr. Huggins
• Mr. Gutschlag

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May 5, 2009
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Outline

• Problem Statement
• Multi-Year Product Overview
• Phase 1 Goals
• Drive Model
• Battery Discussion
• Motor Discussion
• Controller Discussion
• Platform Discussion
• Data Acquisition
• Vehicle Test Data
• Phase 1 Conclusions
• Further Developmental Goals

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MEUV Problem Statement

• As energy costs and concerns for the environment
  rise due to the constantly increasing use of
  fossil fuels, there has been a push towards
  alternative energy sources and products with a
  low carbon footprint. Carbon emissions and the
  nation's dependence on dwindling fossil fuels can
  be drastically reduced by shifting towards more
  efficient or renewable energy sources for
  transportation.
• Current Issues
• Concerns for the environment
• Carbon emissions
• Inefficient fuel consumption
• Dwindling fossil fuels
• Rising gas prices
• Dependence on foreign oil
• Untapped potential market

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Multi-Year Project Overview

• The Electrical and Computer Engineering
  Department at Bradley University has launched a
  multi-year project to design a commercially
  viable urban electric vehicle with a low carbon
  footprint. The vehicle will be ultra compact,
  lightweight, and street legal. This final
  vehicle will strive to solve these issues by
  having
• Zero carbon emissions with the use of a
  stationary battery array charged by photovoltaic
  solar panels and/or wind power generators
• Speed capabilities of up to 65 mph
• Fully optimized regenerative braking
• Fully optimized battery system capable of
  reliable daily use while powering all additional
  auxiliary systems

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Phase 1 Goals

• Design and implement a prototype electric vehicle
  test
• platform for testing with the following
• specifications
• Maximum speed of 25 mph
• Curb weight of 800 to 1800 lbs
• Implement regenerative braking
• Research
• Create drive model
• Determine vehicle properties
• Select optimal components for test platform
• Battery
• DC-Motor
• Control electronics
• Acquire and display data from the motor
  controller and sensors
• Analyze and evaluate drive model

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System Block Diagram
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Drive Model

• Weight, Trip Length, Stops, Max Velocity, and
  Acceleration Time can be varied
• Calculates Energy, Power, Torque, and Wheel Speed
• Used to evaluate motor and battery technology

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Drive Model
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Drive Model
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Battery

• Which battery is the best for this EV?
• Lead-Acid
• Nickel-Metal-Hydride
• Lithium-Ion

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Battery Lead-Acid

• Advantages
• Inexpensive, simple to manufacture.
• Mature, understood technology.
• Capable of high discharge rates.
• High power-to-weight ratio.

• Disadvantages
• Low-energy density.
• Weight
• Limited number of full discharges.
• Full discharges can reduce capacity
  significantly.
• Lead content environmentally unfriendly.

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Battery Lithium-Ion

• Advantages
• Extremely light.
• Large energy density.
• No memory.
• Environmentally friendly.

• Disadvantages
• Unstable.
• Can lose 50 of capacity in 1 year.
• Known to fail after only 3 years.
• Very high cost.

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Battery Lithium-Ion

• Most popular battery for small applications.
• Used in many up and coming EVs.
• Chevrolet Volt
• Tesla Roadster

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Source http//www.techfeed.ca
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Battery - NiMH

• Advantages
• Environmentally friendly safe to dispose. Easy
  to recycle.
• High number of discharge cycles.
• High energy density.
• Can be stored at charged state without losing
  capacity.
• Weight.

• Disadvantages
• Limited discharge current.
• Complex charger needed.
• Cost.

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Battery - NiMH

• Most often used battery in commercial hybrids.
• Toyota Prius
• Honda Insight
• Honda Civic Hybrid
• Ford Escape Hybrid
• Used in commercial EVs.
• GM EV1
• Honda EV Plus
• Ford Ranger EV

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Battery - Comparison
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Source Pesaran, Ahmad. Battery Choices for
Different Plug-in HEV Configurations
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Battery - Comparison
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Source Pesaran, Ahmad. Battery Choices for
Different Plug-in HEV Configurations
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Battery - Selection

• NiMH
• Weight.
• Environmentally friendly.
• High number of discharge cycles.
• Good middle ground between cost and weight.
• 48V packs.
• Problems
• Extremely difficult to purchase in small
  quantities.

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Battery - Selection

• Lead-Acid
• Readily available.
• Cost.
• Testing purposes.
• Optimize Test Platform

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Motor

• Which motor is the best for this EV?
• 3 Phase AC Induction
• Permanent Magnet DC
• Series-Wound Brushed DC
• Separately-Excited Brushed DC

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3 Phase AC Induction

• Pros
• Very high efficiency
• Very high RPM
• Long power band
• Smooth Torque
• Easy reversing and regenerative braking

• Cons
• Very expensive motor and controller
• Power inversion circuitry needed

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Permanent Magnet DC

• Pros
• Very high efficiency
• Compact pancake design cuts down on weight and
  frees up space

• Cons
• Expensive motor and controller for electric
  vehicle applications

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Series-Wound Brushed DC

• Pros
• Very high low end torque making them very
  suitable for large vehicles and fast acceleration
• Can be overloaded many times without damage
• Good price to power ratio

• Cons
• Regenerative braking is difficult, inefficient,
  and dangerous
• Brushes require maintenance or replacement
• Not as efficient as other motor types

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Separately-Excited Brushed DC

• Pros
• More efficient than Series-Wound Brushed motors
• High RPM range, low end torque, and top speed
• Easy reversing and regenerative braking

• Cons
• Brushes require maintenance or replacement

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Motor

• DD Separately Excited
• Model ES-10E-33
• 8 HP Continuous
• 6.7 Diameter
• 11 Length
• 56 lbs
• 7/8 x 2 Shaft
• 3/16 Keyway

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Controller

• Alltrax DCX600
• 24-48V Battery Input
• 600 Amp Limit for 2 minutes
• 30 Amp Field Winding Limit
• Standby current lt 35mA
• Drives motor to 17 peak HP
• 18 kHz Operating Frequency
• -25 C to 75 C Operating Temperature
• 95 C shutdown

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Controller

• User Inputs
• Key switch
• Reverse Mode
• Throttle
• Throttle Options
• Resistive 0-5 k?
• or 5k-0 ?
• 0-5 V or 6-10 V
• Programmable via RS232 Communication Port using
  PC

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Controller Software

• ControllerPro Adjustable Parameters
• Throttle acceleration / deceleration ramp rate
• Throttle curve profile (linear, progressive,
  S-Curve)
• Max Armature current limit (0-100)
• Brake current limit (0-100)

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Controller Software

• Under / Over voltage shutdown
• Top Speed (0-100)
• Half Speed Reverse
• High Pedal Disable
• Plug Brake

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Motor Modeling Why?

• To get a better sense of the motors
  characteristics.
• Will be useful for regenerative braking.
• Helpful for designing a controller if necessary.
• Will be used by future groups.

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Motor and Controller Testing
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Motor and Controller Testing
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Motor and Controller Test Data
Input Voltage (V) Throttle () Armature Frequency (kHz) Average Armature Voltage (V) Armature Duty Cycle () Average Field Winding Voltage (V) Field Winding Duty Cycle () Shaft Velocity (RPM) Field Winding Current (A) Armature Current (A)
36 0 0 0 0 10.5 30 0 7.8 0
36 25 18.08 7 21.9 7.4 23 536 5.9 6.3
36 50 18.08 16.2 46.18 4.9 15.7 1516 4.1 10.5
36 75 18.08 25.4 70.8 3.7 11.5 3010 3.1 13.5
36 100 18.08 36 100 4.1 10.9 4480 2.9 13.2
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Motor and Controller Test Data
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Motor and Controller Test Data
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Vehicle Platform - Go Karts

• Minimum Load Capacity of 300 lbs
• Space to Mount Four Lead Acid Batteries
• Space for Data Acquisition System

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Vehicle Platform - Go Karts

• 4170 Vector Go Kart from American Sportworks
• Curb Weight 310 lbs
• Maximum Load 300 lbs
• Dimensions
• 72L x 46W x 49H

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Data Acquisition
Data Acquisition
Battery Voltage Motor Controller
Battery Current Motor Controller
Charge left on Battery Calculation
Controller Temperature Motor Controller
Motor RPM Calculation
Wheel RPM Sensor
Velocity Calculation
Acceleration Calculation
Input Controller Current Motor Controller
Motor Torque Calculation
Motor Power Calculation
Throttle Position Motor Controller
Output Controller Current Motor Controller
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Data Acquisition Controller

• Controller Data
• Throttle Position
• Controller Temperature
• Battery Voltage
• Output Current
• Battery Current
• Error Flags

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Data Acquisition Cycle Analyst

• The Cycle Analyst has can display and log many
  parameters such as
• Instantaneous Power Statistics
• Voltage in volts
• Current in Amps
• Power in Watts
• Travel Statistics
• Current speed in km or miles per hour
• Distance traveled and time

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Data Acquisition Cycle Analyst

• Regenerative Braking Statistics
• Max forward and regenerative current
• Energy use in Watt-hours per km or mile
• Percent of extra range gained from regenerative
  braking
• Battery Statistics
• Net energy consumption in Amp-Hours which can be
  used as a fuel gauge
• Net power consumption in Watt-Hours
• Voltage sag on the battery
• Charge/discharge cycles of battery life
• Total amp-hours delivered in battery life

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Data Acquisition

• Vehicle Test Display
• Combines Controller and Cycle Analyst Data
• Displays Data on Laptop for the Driver during a
  Vehicle Test

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Vehicle Test

• Collect Data to Verify Drive Model
• Vary Acceleration Time
• Vary Number of Stops
• Vary Trip Length
• Measure Battery Life
• Observe and Record Regenerative Braking

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Initial Vehicle Test

• First test data

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Initial Vehicle Test
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Initial Vehicle Test
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Vehicle Test Failures

• Battery bulged and cracked possibly due to
• Low quality or defective batteries
• Excessive brake
• current
• Excessive
• discharge current

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Further Vehicle Tests

• Run longer tests
• Safely operate test batteries
• Verify regenerative braking with Cycle Analyst
• Follow drive model

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Phase 1 Conclusions

• Created Drive Model
• Researched and selected components appropriate
  for Test Platform
• Successfully implemented Test Platform
• Found evidence of Regenerative Braking during
  Vehicle Test
• MEUVie

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Further Development

• Improve accuracy of Drive Model
• Construct custom battery solution
• Design model for auxiliary systems
• Design carbon emission free charging system

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Special Thanks

• Dr. Huggins for helping us with defining and
  meeting our goals
• Mr. Gutschlag for helping us with testing and
  modeling of components
• Mr. Mattus for mounting multiple vehicle
  components
• Mr. Schmidt for helping us with hardware
  construction and modification

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References

• Battery Chemistries. Battery University. 2003.
  lthttp//www.batteryuniversity.com/gt
• Most of Us Still Drive to Work Alone. US
  Census Bureau. Public Information Office. June
  13, 2007. lthttp//www.census.gov/Press-Release/www
  /releases/archives/american_community_survey_acs/0
  10230.htmlgt

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Questions?
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Motor Modeling

• To get a better sense of the motors
  characteristics.
• A good learning experience.

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Motor Modeling - Rf

• Small voltage applied through the field winding.
• Vs8.93v
• If8.9A (ammeter)
• Using Ohms Law

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Motor Modeling - Ra

• Apply a voltage across the armature until the
  shaft begins to turn, then back the voltage off
  until the shaft stops.
• This is to prevent the back EMF.
• Vs1.26V
• Ia15.5A (ammeter)
• Using Ohms Law

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Motor Modeling Test Data

• Motor in shunt for data collecting.
• Data to be used to find
• KTTorque Constant
• TS.F.Static Friction
• bViscous Friction Coefficient

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Motor Modeling Test Data
Voltage (V) Armature Current (A) Shaft Velocity (RPM) Shaft Velocity (rad/s) Field Current (A) Armature Resistance (O)
24.2 23 2762 289.09 N/A N/A
24 21.5 2827 295.89 N/A N/A
1.26 15.5 0 0 N/A 0.08129
1.35 15.8 N/A N/A N/A 0.08544
1.3 16.5 N/A N/A N/A 0.07879
24 8 1428 149.46 14 N/A
24 8.1 1438 150.51 13.7 N/A
36 9.7 2017 211.11 18.7 N/A
36 9.3 2044 213.94 18.1 N/A
36 8.5 2048 214.36 17.6 N/A
48 9 2591 271.19 22 N/A
12 6 937 98.07 6.5 N/A
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Motor Modeling Calculations - KT

• Data taken from Vs½Vrated24V
• Ia8.1A Ra.081O
• ?s150.59rad/sec
• Using KVL
• -VsIaRaEa-VsIaRaKE?s0

Torque Constant
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Motor Modeling TS.F. and b

• Storques Tdeveloped-TS.F.-b?sKTIa-TS.F.-b?s0
• One equation, two unknowns. 2 data points.
• Vs12v RPM937 ?s98.07rad/sec Ia6A
• Vs24v RPM1438 ?s150.51rad/sec Ia8.1A
• _at_12v
• (.155)(6)-TS.F.-b(98.07)0
• TS.F.(.155)(6)-b(98.07)
• _at_24v
• (.155)(8.1)-TS.F.-b(1438)0
• (.155)(8.1)-(.155)(6)-b(98.07)-b(1438)0
• b.000243 (Nm)/(rad/sec)
• TS.F.(.155)(6)-(.000243)(98.07)
• TS.F..906177 Nm

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Motor Modeling
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Controller - Simulated Load Testing

• Power resistors simulated loaded motor
• Observe any controller feedback.
• Attempt to record Output Current on Controller

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Vehicle Platform - Go Karts
70 CC Go-Kart Model XT70GK Dimension
60"x38"x45" Weight 172 lbs
150 CC Double Seat Go-Kart Model XT150GK2R
Dimension 96 "x55.2"x58" Weight 386 lbs
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Data Acquisition Controller

• Controller Log File

TimeStamp, ThrottlePos, DiodeTemp, BatteryVoltage, OutputCurrent, BatteryCurrent, ErrorFlags
02/10/09 092735.948 100, 27.1, 18.1, 0.0, 0.0, 0x25
02/10/09 092736.950 100, 27.1, 17.9, 0.0, 0.0, 0x25
02/10/09 092737.951 100, 27.6, 18.0, 0.0, 0.0, 0x35
02/10/09 092738.952 100, 27.1, 17.9, 0.0, 0.0, 0x25
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Drive Model
Curb Weight (kg) Total Weight (kg) Trip Length (km) Stops Maximum Velocity (m/s) Average Velocity (m/s) Acceleration Time (s) Acceleration (m/s²)
350 500 40 0 18 17.9757 6 3
Kinetic Energy with 0 Loss (kJ) Steady State Energy with 5 Loss (kJ) Steady State Energy with 10 Loss (kJ) Steady State Energy with 20 Loss (kJ) Total Kinetic Energy with 5 Loss (kJ) Total Kinetic Energy with 10 Loss (kJ) Total Kinetic Energy with 20 Loss (kJ) Steady State Power with 5 Loss (kW)
81 4.039065 8.07813 16.15626 89.089065 97.17813 113.35626 0.0018225
Steady State Power with 10 Loss (kW) Steady State Power with 20 Loss (kW) Peak Power (kW) Force (N) Torque (N m) Motor Power (kW) Avg. Wheel Speed (rpm) Wheel Radius (m)
0.003645 0.00729 27 1500 375 26.96355 686.9694 0.25
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