1. REMC Team Presentation
Nathan Paddock, CEO
Mark Edmonson, CFO
Dr. Brown, Advisor
Dr. Zavodney, Customer

2. Outline
• Mission Statement/Project Goals
• Start of Semester Project Status
• Redesign
• Competition
• Testing
• Next Steps
• Conclusion

3. History
• 2014 Shell Eco Marathon (SEM) mandates student-
designed Motor Controllers
• 2013-14 HEEV team designs two motor controllers
• V 1.0
• Used Allegro MOSFET driver, proved unreliable
• V1.1
• Tried custom-making MOSFET driver, proved
unreliable

4. Sting

5. Sting Electrical System

6. Present State

7. History
• 2014 Shell Eco Marathon (SEM) mandates student-
designed Motor Controllers
• 2013-14 HEEV team designs two motor controllers
• V 1.0
• Used Allegro MOSFET driver, proved unreliable
• V1.1
• Tried custom-making MOSFET driver, proved
unreliable

8. REMC Mission
• Design a reliable motor controller for Sting,
Cedarville’s all-electric prototype vehicle, which
will be entered in the 2015 Shell Eco Marathon. The
motor controller must be designed for at least 85%
efficiency and must protect itself and the other
electrical components in the system from
dangerous conditions that might exist during the
race.

9. DC Motor Theory
• Rarmature sets current
• Current controls motor
torque
• Motor torque spins wheels

10. System Diagram

11. Suspected Problems
• Transient Over-voltages
• Transient Over-currents
• Excessive Switching losses in MOSFETs
• Improper feedback control

12. Parasitic Capacitance and Inductance
• Parasitic Capacitance occurs when two traces are
too close together
• Parasitic Inductance happens when the traces
form inductance loops

13. Control System
• Feedback Control Loop
• Data gathering
• Current tasks:
• Currently deciphering code
• Adjusting code to V1.0

14. Feedback Control Loop

15. Control System
• Data gathering
• Store data on chip for
analysis
• Send data to ground
station

16. Control System
• Current tasks:
• Currently deciphering code
• Adjusting code to V1.0

17. Control System
• Feedback Control Loop
• Data gathering
• Current tasks:
• Currently deciphering code
• Adjusting code to V1.0
• Move from Advanced Waveform
Extension (AWeX) to normal output
Net V1.0 Pin V1.1 Pin
M_RESET PA7 PA7
M_PWM PA6 PC5
M_FAULT PA5 PA5
MOTOR_TEMP PA4 PA4
THROTTLE PA2 PA2
MANUAL_SWITCH PA1 PA1
2.5V_REF PA0 PA0
BATT_VOLTAGE PB3 PB3
C_FAULT PB2 PB2
CURRENT PB1 PB1
TEMP_BOARD PB0 PB0
MC_TX PC3 PC3
MC_RX PC2 PC2
C_FAULT_EN PC1 PC1
USB_D+ PD7 PD7
USB_D- PD6 PD6
SPARE_1 PD3 PD3
SPARE_2 PD5 PD5
SPARE_3 PA3 PA3
SPARE_4 PD4 PD4
STATUS_LED PD2 PD2
SPARE_LED1 PD1 PD1
SPARE_LED2 PD0 PD0
SPARE_OUT PC4

18. • No useful schematics
• Add 12v to 5v DC/DC Converter
• Suspect EMI Problems
Board Layout

19. Power Stage
Nathan Paddock, CEO

20. Outline
• Responsibilities
• Progress
• Power Stage
• Goals/Deadlines

21. Responsibilities/Progress
• Plan of Action
• Background Research
• Reverse Engineering
• Version 1.0 Prototype Board
• New Components
• Expected Results

22. System Block Diagram

23. Power Stage
• Input
• Driver
• MOSFETs
• Output

24. Allegro A3946 Half-Bridge Controller

25. Allegro A3946 Half-Bridge Controller
http://www.powerguru.org/the-half-bridge-circuit-revealed/

26. N-Channel MOSFETs
• STB35N65M5
• Extremely low on-resistance
• Excellent switching performance
• High dv/dt capability
• Superior power density
• Outstanding efficiency

27. Driver and MOSFET Board Layout

28. Prototype Board

29. Power Stage Schematic

30. Important Components

31. Boot Cap and Gate Resistors
• Boot Cap Formula: CBOOT = (QGATE × 20 )/ VBOOT
• Purpose
• Duty Cycle Adjustment
• PWM Frequency
• Voltage Drop Across MOSFET gate
• Gate Resistors

32. Driver Datasheet CBOOT and Gate Res.

33. Suspected Problems/Issues
• Voltage Transients
• Gate Resistors
• Back EMF: From motor, causes overheating
• Creepage Distance: Can introduce noise

34. Creepage/Clearance

35. Deadlines
• Populate Prototype Board by end of Fall semester
• Redesigned PCB fabricated by 1 March
• In-vehicle testing by 15 March
• Competition April 9th

36. Conclusion
• Mission Statement
• History/Problems Encountered
• Control System: progress/suspected issues/goals
• Board Layout: progress/suspected issues/goals
• Power System: progress/suspected issues/goals
• Prototype Board

37. • Questions?