ECE 390 Independent Study Formula Electric Vehicle John Gehrig - - PowerPoint PPT Presentation

ECE 390 Independent Study

Formula Electric Vehicle

John Gehrig Fall 2015

Project Overview

• Fomula Hybrid Vehicle Competition

– Full Electric Vehicle – Cooperation Mechanical Engineering Department

• Deliver Tractive System

– High Voltage Battery – Low Voltage Battery – System Wiring – Electric Motor

Objectives

• Provide Framework for CAN Communication

– PACMAN Computer – Embedded Software/Hardware

• Improve on 2015 Design Efforts
• System Documentation

– AMS Boards – PACMAN – Pack Wiring – CAN Bus

Design Requirements

• Formula SAE Hybrid Rules 2016

–

http://www.formula-hybrid.org/wp-content/uploads/2016-Formula-Hybrid-Rules-Rev-0.pdf

• Lafayette 2015 Statement of Work

–

http://sites.lafayette.edu/ece492-sp15/files/2015/02/LFEV-Y3-2015-01-20.pdf

System Overivew

JGB HUFF DYNOMOMETER CAN ISOLATO R SCPI USB

TCP / IP

REMOTE COMPUTER

REST API

PACMAN

AMS 1 AMS 7

BATTERY PACK RACK MOUNTED COMPUTER MAGNA POWER SUPPLY

CAN ISOLATOR

MOTOR CONTROLLER SYSTEM CAN BUS SCPI RS232

CAN Communication

CAN Communication

PACMAN Hardware

• Pack Mangement

Computer System

• Isolated Power
• Control Software

– Charge Control – AMS Communication – CAN Communication

• Hardware Watchdog

Past PACMAN Hardware

• No CAN Bus
• Linux Kernel 2.6.36

– SocketCAN (2.6.25) – Complicated

• Power Consumption
• High Cost

– $238 Board – $50+ BOB

PACMAN Software

• Atmel AVR Microcontroller

– Low Power – Integrated CAN Communication – Open Source Toolchain – Atmel Software Framework

• Real Time Operating System (AtomThreads)
• Focus on Hardware Abstraction Layer

PACMAN Software

• GNU Make
• GCC (Atmel AVR Port)

– Arduino Toolchain – Distribution Repositories – Build From Scratch

• Documented with Doxygen
• VirtualBox Build Environment

Software Organization

• Atmel ASF
• Exhuberent Ctags
• AVRDude
• Library Support
• Mercurial Repository

– Atlassian BitBucket – Facebook

RTOS Task Control

/** * @brief Task Description Structure */ typedef struct { ATOM_TCB *tcb_ptr; uint8_t priority; void (*entry_point)(uint32_t); void (*init_func)(uint32_t); uint32_t entry_param; void *stack_top; uint32_t stack_size; } ATOM_TASK; // GUI and user input task {&task_gui_tcb, 16, task_gui, task_gui_init, 0, &task_gui_stack[TASK_GUI_SIZE-1], TASK_GUI_SIZE},

GPIO Control

/** * @brief GPIO Pin Data Structure */ typedef struct { volatile uint8_t* port; volatile uint8_t* ddr; volatile uint8_t* pin; uint8_t pin_num; } GPIO_PIN; /** * @brief GPIO Pin Digital Output */ static inline void pinWrite(GPIO_PIN pin, uint8_t value) { *pin.port = (*pin.port & ~_BV(pin.pin_num)) | (value << pin.pin_num); }

AMS API

// Clear AMS Bypass Mode void ams_reset_bypass(uint8_t addr) { unsigned char msg[2] = { (addr << 1), // device address (write mode) RESET_BY, // device command }; // take mutex, wait until available atomMutexGet(&i2c_mutex, 0); // send data on i2c bus TWI_Start_Transceiver_With_Data(&msg[0], sizeof(msg)); // release mutex atomMutexPut(&i2c_mutex); }

State of Charge Algorithm

• How can battery SOC be measured?
• Coulomb Counter

– Initial Condition must be ACCURATE – Unstable system (measurement error)

• Voltage Model

– Noisy, requires low pass filter – Susceptible to transient current spikes

State of Charge Algorithm

• Mixed Mode Charge Estimation Algorithm

– Stable System – Requires NO initial condition – Fast transient response – Low Noise

• IEEE Paper (2009)

– Control Theory

Codeca, F.; Savaresi, S.M.; Manzoni, V., "The mix estimation algorithm for battery State-of-Charge estimator- Analysis of the sensitivity to measurement errors.," in Decision and Control, 2009 held jointly with the 2009 28th Chinese Control Conference. CDC/CCC 2009. Proceedings of the 48th IEEE Conference on , vol., no., pp.8083-8088, 15-18 Dec. 2009

State of Charge Algorithm

State of Charge Algorithm

State of Charge Algorithm

LifePO4 Datasheet Simulink Model (Lookup Table) Simulink Results Sample Model Response

AMS

• No, the AMS Firmware wasnt fixed…

– Incorrect Bypass Timeout – One Monolithic File ~1000 lines – Power Consumption

• Modularization of Code Base
• Watchdog Sleep

– Reduces Power Consumption (< 50 %) – Watchdog Timer Ticks Every ¼ Second

AMS Software

• Changed TIMER1 to WDT

– TIMER1 does not run in sleep mode

• All I2C calls are function based
• VirtualBox Build Environment

– Repeatable, Consistent – PicKit3 Doesn't work in latest MPLAB Version

• Optimizer Issues?

AMS Software

int main(void){ // initialize the slave PIC, enable interrupts setup(); // enable global and peripheral interrupts INTCONbits.PEIE = 1; INTCONbits.GIE = 1; // save power while waiting for interrupts while(1) { // place PIC in sleep mode SLEEP(); // WDT wakeup occured, handle event_wdt(); } return 0; }

AMS Verification

• Automate AMS Testing

– 28+ AMS Boards – Time Saving – Machine Shop

• Thorough Verification
• Validate Software
• Arduino Controlled

– Easy to Build – Simple, Low Cost

AMS Test Port

EV 3.7.10 AMS Test Port

A break-out test connector must be provided inside the accumulator enclosure for AMS voltage testing. This port allows testing of the AMS by substituting a test box voltage for a measured cell voltage. Currently Design is Incompliant

Pack Wiring & Cabling

• Reduce Wiring Complexity
• Replace Screw Terminals
• Specify Connector Pinouts
• Buy Proper Wires, Cables
• Simply Wiring Diagram

Deutsch DT Connectors

• Huff Dynomometer
• Waterproof
• Strain Relief
• Ease of Assembly
• Professional
• Industry Standard

LFEV Pack Connectors

GLV CONNECTOR

1 – CANH (YELLOW) 6 – CANL (GREEN) 2 - GND(BLACK) 5 - +12V (RED) 3 - RSVD (BROWN) 4 – RSVD (WHITE)

SAFETY LOOP CONNECTOR

1 – GND (BLACK) 4 – +24V (RED) 2 – SLOOP_A (WHITE) 3 – SLOOP_B (BROWN)

AMS/I2C CONNECTOR

1 – RST_NEG (PACK-) 6 – RST_POS 2 – SDA_HV 5 – SCL_HV 3 – SVDD (+5V) 4 – SVSS (PACK-)

LFEV Pack Connectors

20 Gage Wire

Demonstration System

• 3D CAD Model

– Creo Parametric – AutoCAD

• Laser Cut Acrylic

– New Laser Cutter

• Battery Pack Model
• Bench Power Supply

Demonstration System

QUESTIONS

&

COMMENTS