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EV-EMCU Electric Vehicle - Economy Mode Control Unit

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

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EV-EMCU Electric Vehicle - Economy Mode Control Unit

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  1. EV-EMCUElectric Vehicle - Economy Mode Control Unit Shauntice DiazChris ChadmanVanessa Baltacioglu Group 4

  2. 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

  3. 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

  4. Overall Block Diagram

  5. 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

  6. Physics

  7. Physics • 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

  8. 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

  9. Sensors • 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 • 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

  10. Speed Sensor • ’94 Transmission, ’04 Vehicle • Electrical Sensor added PWM • Measured from Transmission or Rear Diff (ABS)

  11. 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

  12. 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

  13. State of Charge • PakTrakr 600EV • Measures current, SOC, and battery Temp • RS-232 output • Expensive

  14. 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

  15. 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

  16. 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 Microcontroller

  17. 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

  18. 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

  19. Power Controller • 7 inputs from sensor microcontroller • Heartbeat • Computes optimum acceleration • Test Data • Peukert’s Law • Battery Resistance • Outputs to safety microcontroller

  20. Safety Microcontroller • 3 Inputs: Potentiometer, Power MCU, and Reset • 3 Outputs: Motor controller, WDT, and Data • Acts like typical a comparator • Prevents runaway acceleration

  21. 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

  22. 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.

  23. WatchDog Timer • Used to monitor and minimize errors • Timeout period and reset period • Two types • Hardware (external) • Software (internal)

  24. Internal Watchdog Timer • Negatives • Almost all can be disabled by software • Positives • Cost is essentially zero • Can save debugging information • Convenient • Can modify timeout • Can vary less with temperature

  25. External Watchdog Timer • Negatives • Cost • Timeout period varies • One I/O line • Timeout must be calculated (both high and low speed) • Positives • Cant be disable accidentally • Separate clock source • Min/Max timeout period • Reset can connect to other system • Timeout period is adjustable

  26. 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

  27. Original Goals & Specifications • Solar assisted EV conversion • Range of 60+ miles • User friendly display (touch screen) • DOT approved • Wireless applications • Regenerative braking • Power steering

  28. 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

  29. Budget • Electric truck from Tecta America - FREEEagle 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)

  30. Progress

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