Download Shauntice Diaz Chris Chadman Vanessa Baltacioglu

EV-EMCU
Electric Vehicle - Economy
Mode Control Unit
Shauntice Diaz
Chris Chadman
Vanessa Baltacioglu
Group 4
Goals & Objectives
• Extend range by implementing economy-mode
• Minimize power usage by attenuating
acceleration to an optimum value
• Use several microcontrollers to allow data
recording, vehicle safety, and to calculate
optimum power usage
• Take in user’s inputs such as current, State of
charge, RPMs, MPH, temperature, and
acceleration
• USB storage or SD card
• Intelligent driving system
• DOT Approved
Specifications & Requirements
• To increase range by 5-10%
• 12V auxiliary power supply
• 144V vehicle power supply
• 7 electrical sensors
• 5v power supply for microcontrollers
• Data recording for 90 minutes
• C language
Overall Block Diagram
Physics
• Relate Electric Power to Mechanical Power
• Find Minimum Acceleration for Economy Mode
• Minimize Electric Power Loss through Heat by Limiting
Current / Acceleration
• Find Power Needed for Acceleration
Pin = VIin = 220.46v + 0.87v3 + vma + vmg*SIN(θ)
Pr
Pa
• Current as a Function of Acceleration and Velocity
I = [220.46v + 34.32v2 + 13,789v*sinθ + 1406va] / V
• Max Current ~ 350 A; Attenuate Potentiometer as % of I
• Test Values
Physics
Physics
 C 
t  H

 H *I 
• Peukert’s Law:
t = Time of Discharge
H = Rated discharge Time (hrs)
C = Rated Capacity @
Discharge Time t
I = Discharge Current
K = Peukert’s Constant
K
Peukert's Law
10.00
9.00
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Hours
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Amps
Physics
• Internal Battery Resistance
▫ EV12A- AGM; Ri = 3.2mΩ
▫ Full Power VI = 144V*350A = 50.4
kW
▫ Power Loss @ 350A = 4.7 kW;
9.5%
▫ Temperature Effects
Sensors
• Speed
▫ 0 to 70 miles per
hour
▫ Pulse Width
Modulation
• RPM
▫ 0 to 5000
Revolutions Per
Minute
▫ Pulse Width
Modulation
• Current
▫ -500 to 500 Amps
▫ Analog
• State Of Charge
▫ 10.5volts – 13. 2
Volts ( 0 to 100%)
▫ Analog
• Battery Temperature
▫ -40 ̊C to 60 ̊C
▫ Analog
• Potentiometer
▫ 0-12Volts
▫ Analog
• Accelerometer
▫ ± 2g’s (horizontal)
▫ Analog
Speed Sensor
• ’94 Transmission, ’04 Vehicle
• Electrical Sensor added PWM
• Measured from Transmission or Rear Diff (ABS)
RPM sensor
• Measured from motor using Hall Effect
• Recommend by NetGain
• Operates under 12V(DC) power supply
• 2.2K integrated resistor
• Pulse width modulated output 5.5 mA
Current sensor
• Hall Effect current sensor
• From EV source recommended by NetGain
• Series connection to 144V system
• Measures the range of ±500 Amps
• Output signal of 1.5 to 4.5 Volts
• Linearly related
State of Charge
• PakTrakr 600EV
• Measures current, SOC, and battery Temp
• RS-232 output
• Expensive
Accelerometer
• Dimensions
Engineering
• Had specs that met
the requirements
• Simple design
• ±2g to the velocity
plane of the vehicle
• Internal 3.3v
voltage regulator
• Output in volts
[XOUT – (VCC / 2)] / sensitivity =
acceleration in the x direction
Potentiometer
• 0-12v controlled by
user
• Step down to 0-5v
• Previously installed
• Controls the motor
controller
• Will adjust output of
potbox according to
power microcontroller
Microcontroller
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PIC16F886 Microchip Technologies
28 Pin DIP
14 10 bit A/D Converters
2 8 bit Timers
2 Analog Comparators
2 Output 10bit PWM
Designed for Intelligent
Driving System
Development Board
• 28 Pin LIN Demo
Board, Microchip
Technologies
• For Use with Most
28 Pin DIP PIC
MCU’s
• Programmed with
PICkit 2
Micorcontroller
Programmer
Sensor Microcontroller
• 5 analog inputs
(current, accelerometer,
potentiometer,
Temperature, and state
of Charge )
• Two PWM (speed,
rpm)
• Reset
• Heartbeat
• 7 outputs to power and
data microcontrollers
Power Controller
• 7 inputs from sensor
microcontroller
• Heartbeat
• Computes optimum
acceleration
▫ Test Data
▫ Peukert’s Law
▫ Battery Resistance
• Outputs to safety
microcontroller
Safety Microcontroller
• 3 Inputs: Potentiometer,
Power MCU, and Reset
• 3 Outputs: Motor
controller, WDT, and Data
• Acts like typical a
comparator
• Prevents runaway
acceleration
Data Microcontroller
• 7 inputs from sensor
controller
• 1 from Power, 1 from
safety
• 1 Reset,1 heartbeat
• 1 Output from
USBwiz to
microcontroller
▫ 3 ways
 UART
 I2C
 SPI
Data Microcontroller:
USBWiz
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Fully assembled and tested
2 USB and SD connectors
Single 3.3 V regulator
Ready for 32 Khz crystal
Complete ‘C’ source code
library
Support fat file system
Easy connection with PIC and
AVR
40 to 50 mA, power
consumption
5v tolerant I/O pins
-40 °C to + 85°C temperature
operation range
Lead free.
WatchDog Timer
• Used to monitor and
minimize errors
• Timeout period and reset
period
• Two types
▫ Hardware (external)
▫ Software (internal)
Internal Watchdog Timer
• Positives
▫ Cost is essentially
zero
▫ Can save debugging
information
▫ Convenient
▫ Can modify timeout
▫ Can vary less with
temperature
• Negatives
▫ Almost all can be
disabled by software
External Watchdog Timer
• Positives
▫ Cant be disable
accidentally
▫ Separate clock source
▫ Min/Max timeout
period
▫ Reset can connect to
other system
▫ Timeout period is
adjustable
• Negatives
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Cost
Timeout period varies
One I/O line
Timeout must be
calculated (both high
and low speed)
Our decision
• External
• Capacitor adjustable
▫ Voltage monitoring
▫ 1.565v to 5v
▫ Watchdog timeout
▫ 700ms to 70s
(100pF to 100nF
capacitor)
▫ Reset timeout
▫ Preset, or 0.5 ms
to 5s by
capacitor
Original Goals & Specifications
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Solar assisted EV conversion
Range of 60+ miles
User friendly display (touch screen)
DOT approved
Wireless applications
Regenerative braking
Power steering
Changes From Original Design
• Batteries
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12 12v swap for 24 6v (cost $2400)
Battery weight from 1074 to 1488 pounds (38.5% increase)
Not much engineering design required
Main benefit would be longer battery life
• Touch Screen Display
▫ Lost computer engineering student in our group who was
working on this part
• Solar Panels
▫ Tecta America (who installs solar roof panels) advised us
against using solar panels
▫ Not enough surface area to produce enough energy to be
worthwhile
Budget
• Electric truck from Tecta America - FREE
Eagle PCB - $50
• Microcontrollers – QTY 10 @ $2 each = $20
• Development board – $40
• Op-amps – QTY 20 @ $0.38 = $8.00
• USBWIZ - $50
• Speed Sensor – $49
• RPM sensor – $99
• Hall Effect current sensor – $49
• PakTrakr 600 EV sensor (Battery Temp and S.O.C.) – $150
• Extra PakTrakr remote - $70
• Accelerometer – $23
• WatchDog Timer – QTY 15 @ $1.56 = $24
• Soldering Iron with station (Amazon) – $50
• Breadboard Kit (Amazon) – $25
• Waterproof box – TBA (with final dimensions)
Miscellaneous (wiring, bolts, tax, shipping, etc) - $100
Total Estimate: $807
• Old total : $3500 (with batteries and touch screen display)
Progress
Research
75
Design
75
40
Order
5
Build
10
Test
0
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40
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60
Percentage
70
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90
100