ev-emcu electric vehicle - economy mode control unit
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
EV-EMCUEV-EMCUElectric Vehicle - Economy Electric Vehicle - Economy
Mode Control UnitMode Control Unit
Shauntice DiazChris 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 VelocityI = [220.46v + 34.32v2 + 13,789v*sinθ + 1406va] / V
• Max Current ~ 350 A; Attenuate Potentiometer as % of I• Test Values
Physics
Physics•Peukert’s Law:
t = Time of DischargeH = Rated discharge Time (hrs)C = Rated Capacity @
Discharge Time tI = Discharge CurrentK = Peukert’s Constant
K
IH
CHt
*
Peukert's Law
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270
Amps
Ho
urs
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 NC to 60 NC▫ 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•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
• 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 ▫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
•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
▫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) - $100Total Estimate: $807
• Old total : $3500 (with batteries and touch screen display)
Progress