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System for Motor Control in a Solar Powered Electric Race Car
Jay OattsDuncan Thompson
Pavel RybakovAlex Jenkins
Ed Kfir
Monday November 1, 2010
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Project Overview
• Design motor controlling system for solar-powered race car to participate in 2011 World Solar Challenge in Australia
• Modular design for efficient portability to solar racer and integration with full electronics system
• Expected cost of replication for Solar Jackets is approximately $550
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Technical Objectives
• 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 Group ECE 4007L01 – ws3
Current Status
• Test bench construction complete• Motor controller and motor functional (only
one of each)• Operation in discrete (human interface) and
serial (computer interface) confirmed• Safety systems installed• Semi-full systems test passed (SBC and LCD
excluded)
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Modular Design
• Power Source• Motor Controller
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Modular Design
• Power Source• Motor Controller• Motor
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Modular Design
• Power Source• Motor Controller• Motor• Discrete Controls
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Modular Design
• Power Source• Motor Controller• Motor• Discrete Controls• SBC
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Modular Design
• Power Source• Motor Controller• Motor• Discrete Controls• SBC• Driver Display
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Power Source - Batteries
• 8 x 12V series connection
• 96V effective• Wiring – AWG-4
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Power Source - Fuse
• 250V / 150A rated fuse and holder
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Power Source – Main Power Cutoff
• 48V/96V blowout• 1000A• Keyed access
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Power Source – Power Relay
• Contactor– 900V / 500A
(cont.) / 2000A (cutoff)
• Power Resistor– 100Ω/200W
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Motor Controller - Connections
• Battery Terminals
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Motor Controller - Connections
• Battery Terminals• Motor 3-Phase Power
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Motor Controller - Connections
• Battery Terminals• Motor 3-Phase Power• Motor Sense (15 pin)
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Motor Controller - Connections
• Battery Terminals• Motor 3-Phase Power• Motor Sense (15 pin)• Discrete/Serial
Controls (25 pin)
Solar Jackets – Motor Controller Group ECE 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 Group ECE 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 Group ECE 4007L01 – ws3
Motor Controller - Communication• Split from 25 pin controls cable • Serial-USB for computer • Hyperterminal program• 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)
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Note: XX implies register hexadecimal number for RAM/EEPROM or command number. # implies decimal value to be assigned to the register
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 Group ECE 4007L01 – ws3
Discrete Controls - Switches
• Enable– Master controller enable
(must be on to operate)
Solar Jackets – Motor Controller Group ECE 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 Group ECE 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 Group ECE 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 Group ECE 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 (as long as motor is currently rotating forward)
Solar Jackets – Motor Controller Group ECE 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 (as long as motor is currently rotating forward)
• Speed Pulse– State change every two
consecutive commutations
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Discrete Controls – Pedals
• Throttle– Analog input
(potentiometer for now) to scale throttle from 0-5V
Solar Jackets – Motor Controller Group ECE 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 Group ECE 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
• Air Gap – Mentioned in manual, but
ultimately unused
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Single Board Computer (SBC)
• Serial interface cable connects to serial port in place of laptop
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Single Board Computer (SBC)
• Serial interface cable connects to serial port in place of laptop
• 1x 10/100 Ethernet, 2x USB2.0
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Single Board Computer (SBC)
• Serial interface cable connects to serial port in place of laptop
• 1x 10/100 Ethernet, 2x USB2.0• Boots Linux in about 3 seconds• RS-485 multi-drop network for
communication with solar cell switching power supplies
• Connects and operates LCD driver display
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Driver Display• Potential display choice• Connects to SBC on
either SPI or I2C bus• LED backlighting• Many colors available• Affordable for basic
testing• Nothing purchased yet
and open to feedback
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
F R Cruise Control
Speed: 55 mph @ 1200 RPMRegen: 0% 100%
Power Supply: 96.3V / 20.2AMotor Temp: 30°CController Temp: 25°C
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, 870dHz measured rotation (1740 RPM estimated)
• 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 Group ECE 4007L01 – ws3
Current Issues - Motor• Motor pole count
– Total number of poles not listed in any manuals– Needed to confirm speed calculation from motor
controller • Torque (phase current) control spiking
– Without load, current spikes at turn on to reach max speed and then levels out to nominal current draw
– Need to load motor to further test current range
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Current Issues - Controls• Regenerative braking lights
– Signal every time negative current is recognized by the motor controller (regeneration)
– Not an effective sign of actually braking (light can trigger without regen being applied)
• Throttle/Regen potentiometers (sensitivity)– Current max measured at about half of potentiometer max range– Motor controller registers can modify range and deadband
settings to optimize• LCD screen choice
– Need to decide on LCD screen so information can be viewed continuously from program
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Upcoming Milestones• Basic single board computer I/O
– November 5, 2010• Basic functional LCD user interface
– November 12, 2010• System logic programmed
– November 19, 2010• Automatic programmed motor control
– December 1, 2010
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Discussion• Regenerative braking lights• Torque control spiking (need to load test)• Throttle/Regen potentiometers (sensitivity)• LCD screen decision• Motor pole count
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Brake Lights
Reverse Lights
Motor Controller Interface Cable
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
Detailed Full System
Solar Jackets – Motor Controller Group ECE 4007L01 – ws3
NGM-EV-C200-092
Motor Controller
Cooling Fans
AMP Series 1 CPC 11-4
SC-M150-008
Axial Flux, Permanent Magnet,
DC Brushless Electric Motor
Phase Leads (AWG 4 Wire)
ABC
Motor Communication
Link
DB-15
8 x 12 V Car Battery Series
Array
96 V Effective
120VAC Charger
Wheel(Load)
Linux On-Board Computer
+ve
Power bus(AWG 4 Wire)
-ve
Vehicle Control Signals(DB-25)
Throttle Pedal
User InterfaceLCD Screen
RS-232
SpeedSupply Voltage
Motor TemperatureBrake Regeneration
RPMsDirection
Control Interface
Cable
Switches-Controller Enable-Throttle Enable
-Forward/Reverse Toggle
Cruise Control Buttons-Set
-Accel-Decel-Coast
RS-232
Brake Pedal
Reverse Lights
Brake Lights
Cost AnalysisPart Approximate 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 Group ECE 4007L01 – ws3
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