System for Motor Control in a Solar Powered Electric Race Car Jay Oatts Duncan Thompson Pavel Rybakov Alex Jenkins Ed Kfir Monday December 13, 2010 Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Project Overview Design motor controlling system and driver vitals display for solar-powered race car to participate in 2011 World Solar Challenge in Australia Modular and mostly generic design for efficient portability of some or all of the project to the final solar racer and integrating with other electronics systems present Expected cost of replication for Solar Jackets is approximately $550 Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Technical Objectives (Proposed) Design test bench and implement safety mechanisms Test functionality of motor controller and motor (donated items) Operate motor controller via single-board computer program and discrete controls Output vital data from motor controller to driver via LCD screen Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Actual Design Test rig confirmed operation (or failure) of donated parts (motors and controllers) Safety mechanisms in place to reduce risk Operation of motor in discrete (human interface) and serial (computer interface) confirmed Program written to continuously monitor controller for status and vital information to be displayed onto LCD screen Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Modular Design Lots of interconnections! Break things down As much as possible Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Modular Design Power Source Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Modular Design Power Source Motor Controller Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Modular Design Power Source Motor Controller Motor Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Modular Design Power Source Motor Controller Motor Discrete Controls Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Modular Design Power Source Motor Controller Motor Discrete Controls SBC Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Modular Design Power Source Motor Controller Motor Discrete Controls SBC Driver Display Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Actual Design Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Power Source - Batteries 8 x 12V series connection 96V effective Wiring – AWG-4 Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Power Source - Fuse 250V / 150A rated fuse and holder Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Power Source – Main Power Cutoff 48V/96V blowout 1000A Keyed access Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Power Source – Power Relay Contactor – 900V / 500A (cont.) / 2000A (cutoff) Power Resistor – 100Ω/200W Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Motor Controller - Connections Battery Terminals Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Motor Controller - Connections Battery Terminals Motor 3-Phase Power Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Motor Controller - Connections Battery Terminals Motor 3-Phase Power Motor Sense (15 pin) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Motor Controller - Connections Battery Terminals Motor 3-Phase Power Motor Sense (15 pin) Discrete/Serial Controls (25 pin) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Motor Controller - Connections Battery Terminals Motor 3-Phase Power Motor Sense (15 pin) Discrete/Serial Controls (25 pin) Fan Power Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Motor Controller - Connections Battery Terminals Motor 3-Phase Power Motor Sense (15 pin) Discrete/Serial Controls (25 pin) Fan Power Fans (2 x 24V) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Brushless Electric Motor 3 phase cables connect to attract rotating permanent magnet in sequence Controller sends power to phases relative to desired speed/torque (commutator) Motor sense cable sends information back to controller (Hall effect sensors, temp sensor, connection sense) Mount for support/stability Solar Jackets – Motor Controller GroupECE 4007L01 – ws3 Above: NGM electric motor attached to plate mount with wiring harness for phase cables and motor sense cable.

Motor Controller - Communication Split from 25 pin controls cable Serial-USB for computer Hyperterminal program Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discrete Controls - Switches Enable – Master controller enable (must be on to operate) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discrete Controls - Switches Enable – Master controller enable (must be on to operate) Throttle Enable – Phase current enable (drops to zero when disabled, but regen still operational) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discrete Controls - Switches Enable – Master controller enable (must be on to operate) Throttle Enable – Phase current enable (drops to zero when disabled, but regen still operational) Direction Switch – Forward or Reverse Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discrete Controls – Output Signals Brake (Regen) Light – Activates anytime the controller is regenerating power back to batteries (Phase current negative) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discrete Controls – Output Signals Brake (Regen) Light – Activates anytime the controller is regenerating power back to batteries (Phase current negative) Reverse Light – Activates when reverse switch set Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discrete Controls – Output Signals Brake (Regen) Light – Activates anytime the controller is regenerating power back to batteries (Phase current negative) Reverse Light – Activates when reverse switch set Speed Pulse – State change every two consecutive commutations – Unused in our design, but could be useful to analyze on an oscilloscope Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discrete Controls – Pedals Throttle – Analog input (potentiometer for now) to scale throttle from 0-5V Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discrete Controls – Pedals Throttle – Analog input (potentiometer for now) to scale throttle from 0-5V Regenerative Braking – Same as throttle, but scales amount of regeneration to batteries from motor Solar Jackets – Motor Controller GroupECE 4007L01 – ws3 Note: The potentiometer design used in our design can be scaled for use with pedals. The controls require a 3 lead (vdd, gnd,wiper) configuration that is common to electric potentiometer foot pedals.

Discrete Controls – Pedals Throttle – Analog input (potentiometer for now) to scale throttle from 0-5V Regenerative Braking – Same as throttle, but scales amount of regeneration to batteries from motor Air Gap – NGM thought they could do this, but apparently backed out after the control cable was designed Solar Jackets – Motor Controller GroupECE 4007L01 – ws3 Note: The potentiometer design used in our design can be scaled for use with pedals. The controls require a 3 lead (vdd, gnd,wiper) configuration that is common to electric potentiometer foot pedals.

Single Board Computer (SBC) - External Serial connection to laptop on COM1 for loading and viewing programs Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Single Board Computer (SBC) - External Serial connection to laptop on COM1 for loading and viewing programs 10/100 Ethernet port could also be used Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Single Board Computer (SBC) - External Serial connection to laptop on COM1 for loading and viewing programs 10/100 Ethernet port could also be used SBC external power source, 5V Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Single Board Computer (SBC) - External Serial connection to laptop on COM1 for loading and viewing programs 10/100 Ethernet port could also be used SBC external power source, 5V Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Single Board Computer (SBC) - Internal Serial connection to motor controller via discrete controls box on COM2 expansion Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Single Board Computer (SBC) - Internal Serial connection to motor controller via discrete controls box on COM2 expansion Connection to LCD screen and cruise control switches with Digital Input/Output (DIO) pins Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Communication and Programming USB to Serial – Connects to COM1 on SBC C code compiled in Cygwin – Unix environment for Windows – Additional compiler installed specifically for ARM processor on SBC Transferred to SBC with Hyperterminal – Run binary executable on SBC Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Console Program Displays information received from motor controller every second Can turn off this mode for smoother LCD functionality Roundabout debugging system using print statements in various sections of code for testing Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

LCD & Cruise Control Potential display choice Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Driver LCD Display Potential display choice Advantages – Cheap! – Our example is already in easily modifiable code – Many colors and backlighting options – Low power (about 150uA) Disadvantages – Small (128x64px ) – Additional graphics will have to be hard coded Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Driver LCD Display Display parameters – Battery supply voltage Range 96V – 100% to 50V – 0% Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Driver LCD Display Display parameters – Battery supply voltage Range 96V – 100% to 50V – 0% – Throttle/Regen Current Range from 0A (middle) to +/- 25A Above = throttling, below = regenerating Values will need to be higher once load tested Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Driver LCD Display Display parameters – Direction (Forward or reverse) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Driver LCD Display Display parameters – Direction (Forward or reverse) – Cruise Control (On or Off) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Driver LCD Display Display parameters – Direction (Forward or reverse) – Cruise Control (On or Off) – Speed (Calculated from RPM and wheel size) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Driver LCD Display Display parameters – Direction (Forward or reverse) – Cruise Control (On or Off) – Speed (Calculated from RPM and wheel size) – Temperatures (Motor/ Motor Controller) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Driver LCD Display Display parameters – Direction (Forward or reverse) – Cruise Control (On or Off) – Speed (Calculated from RPM and wheel size) – Temperatures (Motor/ Motor Controller) – Fault Codes (Hexadecimal, match to motor controller manual) Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Cruise Control Cruise Enable Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Cruise Control Cruise Enable Modify speed – Hold up to throttle – Hold down to decelerate Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Acceptance Testing Confirmation of functional motor controller – Connect to 60V power supply at minimal current, measure input/output pin voltages (+5V for signal lines, +24V for fan) Full controls and motor connection – Communication with motor controller, motor rotation, discrete controls operational, fans connected, 866dHz measured rotation (866 RPM) Battery array connection (full power operation) – Torque vs. speed control testing, safety systems operational, 96.3V measured battery power, 200mA full speed (no-load) current draw Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Acceptance Testing Confirmation of programmable motor control with SBC – All motor controller vitals viewable and updated on per second basis Confirmation of functional LCD screen controlled by SBC – Vitals displayed to user-friendly screen that will replace external computer in car Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Existing Issues Cruise Control – Framework works correctly, but motor controller prevents change from serial to discrete or discrete to serial control while coasting – Mostly defeats the point of cruise control since a cruise speed cannot be set or cancelled while moving (however, motor controller can be disabled by brake for safety) – Should be possible since it has been done by other teams using the same controller Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Existing Issues Recurring Faults (Register 3, Fault 0x4) – “Motor has reached maximum throttle or regen current for the current speed” Most likely an incorrect EEPROM register setting that is limiting maximum current, but the culprit has not been found Causing max RPM/speed to top out at 866 RPM/46mph Could be an issue with the motor (internal short, etc.) Testing with rebuilt motor essential Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Existing Issues Recurring Faults (Register 4, Fault 0x80) – “When in discrete speed control, target regen current is greater than limit set by regen input” Very similar to previous fault Most likely due to the same or similar problem (register setting issue or internal motor problem) Fault occurs most often at low speed as motor jerks between throttle and regen, even though discrete regen is turned off Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Bottom Line Did we do everything we proposed? – Yes Is it exactly as proposed? – No, but very close Is it race ready? – Absolutely not Therefore… Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Future Work Resolve existing issues with faults and cruise control Communicate with telemetry and solar power tracking modules over RS-485 multi-drop network Add load testing functionality to test rig Design air gap controller Optimize program for efficient LCD use and serial communication to minimize excess current draw Move necessary components to solar racer Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Discussion / Demo Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Motor Controller Interface Cable Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Detailed Full System Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Program Flow Chart Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Motor Controller Serial Syntax Commands (same as discrete + program/operate mode + hard reset) – XX! Queries – XX? (RAM) – XX> (EEPROM) Assignments – XX=# (RAM) – XX<# (EEPROM) (*Must be in programming mode) Note: XX implies register hexadecimal number for RAM/EEPROM or command number. # implies decimal value to be assigned to the register Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

LCD Specs 128x64 pixels (8x21 characters) SPI Interface Power Supply: V Current Draw: 150uA typical Operating Range: -20 C to 70 C Backlighting: 5-40mA Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

SBC Specs 200 MHz ARM9 CPU 32 MB SDRAM / 32 MB NAND Flash 10/100 Ethernet port 2x USB 2.0 ports 2x Serial COM ports 20 DIO lines Linux OS Solar Jackets – Motor Controller GroupECE 4007L01 – ws3

Cost Analysis PartApproximate Price Littelfuse Slo-Blo Fuse$35 Fuse Holder$55 Kilovac EV-200 Series Contactor$80 Power Resistor$12 Curtis/Albright Battery Disconnect Switch (with recommended extra contacts for 12V line) $90 ($120) 24V Brushless Fan (x2)$20 CPC Fan Connection Plug (and 2 connector pins)$5 TS-7250 SBC (with full duplex RS-485)$150 ($165) AWG-4 Cable (and terminal connectors)$50 TOTAL SUGGESTED COST$542 Solar Jackets – Motor Controller GroupECE 4007L01 – ws3