Early Power Point during development work for the designing winning UTA Formula Hybrid open-wheel

1. Batteries
UTA F11 Hybrid Preliminary Design Presentation and Concepts

2. Batteries
UTA F11 Hybrid Preliminary Design Presentation and Concepts

3. Batteries
UTA F11 Hybrid Preliminary Design PresentationUTA F11 Hybrid Preliminary Design Presentation and Concepts
by
Tobias Overdiek
June 29, 2010

4. by
Tobias Overdiek
June 29, 2010
Special thanks to Chad Molyet, ViKram Nair, Siddarth Kashyap
Attravanam, Jp Merkel, Dan Molkers, Dr. Robert Woods and the
UTA Formula SAE Team
Batteries
UTA F11 Hybrid Preliminary Design Presentation and Concepts

5. Batteries

6. • Static Events
• Presentation 100
• Engineering Design 200
• Dynamic Events
• Acceleration – Electric 75
• Acceleration – Unrestricted 75
• Autocross 150
• Endurance 400
• Total Points 1000
Competition
Competition Points

8. Rear Drive Motor

10. Rear Motor
• Chain Drive 3.4:1 to 4:1 reduction
• Preferably a 100Nm Motor
• Motor will run as a generator driven by the
engine when under 25-30% load to help
recharger the batteries.

11. Top Mounted Motor

12. Side Mounted Motor

13. Side Mounted Motor

14. -20
0
20
40
60
80
100
120
0 20 40 60 80 100
PowerOutput(%)
Throttle Actuation (%)
Throttle Actuation vs. Rear Motor/Engine
Engine
Motor Generating
Motor under Power

15. 0
20
40
60
80
100
120
140
160
180
200
0 20 40 60 80 100
PowerOutput(%)
Throttle Actuation (%)
Throttle Actuation acting on all Drives
- Hybrid Mode -
Rear Axle Combine
Front Axle - Unattenuated
Front Attenuated

16. Important Considerations
• While the clutch is engaged, or during a shift,
the rear motor generation needs to be
disabled to allow smooth shifting. If not, the
car will brake on the rear axle while letting
your foot of the gas. Even though shifting
takes only a fraction of a second, during hard
cornering the car could kick into oversteer due
to a miss shift or driver error.

17. Important Considerations
• While in Electric Exclusive Mode during the
electric acceleration event, the throttle
response gets normalized to a linear response,
for both front and rear motors.
• The brake pedal will always override throttle
on the electric motors. This way during hard
cornering, using the engine to transfer weight
is permissible while left foot braking.

18. Front Wheel Motors

19. Front Wheel Motors
• Brushless DC Motors
• 3.5:1 to 4:1 Planetary Gear Transmission built
into the upright/hub
• Motors in the range of 35-50Nm
• New lighter 4 Piston Caliper (2.1lb)
• Transmission weight: 10lb
Motor Weight: 6-11lb

20. Kit Brushless DC Motors
Parker K Series

21. Kit Brushless DC Motors
Parker K Series
• The frameless kit motors are ideal solutions
for machine designs that require high
performance in small spaces. The kit motors
approach allow for direct integration with a
mechanical transmission device, eliminating
parts that add size and compliance. The use of
frameless kit motors result in a smaller more
reliable motor package.

22. Kit Brushless DC Motors
Parker K Series
• Reduced mechanical complexity
• High performance in a compact package
• Improved dynamic response and settling
• Minimum motor size per application space
• Low cogging for smooth operation
• Low inertia for high acceleration

23. Kit Brushless DC Motors
Parker K Series - Features
• Pre-installed Integral Commutation Board with Hall
Effects is prealigned for easy assembly. Motor and
feedback as integrated unit.
• Rare Earth Magnets provide high flux in a small
volume, high resistance to thermal demagnetizing
• Machined Grooves to securely lock magnets to rotor
and ensures optimized radial location.
• Class H Insulation for high temperature operation (up
to 155ºC) meeting UL approved requirements.
• High Density Copper Winding for low thermal
resistance and consistent performance across all
motors.

55. 0
500
1000
1500
2000
2500
3000
3500
4000
0 20 40 60 80 100 120 140 160 180 200
HeatLoss(W)
Motor Output Torque (Nm)
Heat Loss vs. Torque of various Motors
06210 at TP
03014 at TP
04512 at TP
06211 at TP
06212 at TP

56. 0
500
1000
1500
2000
2500
3000
3500
4000
0 50 100 150 200 250
HeatLoss(W)
Torque generated at Wheel (Nm)
Heat Loss vs. Torque of various Motors
06210 geared
1.840 : 1
03014 geared
2.727 : 1
04512 geared
2.727 : 1
06211 geared
1.840 : 1
06212 DD

59. Batteries

61. Battery Rules
• $6000 price tag limit
• 400V limit
• Accumulator capacity must not exceed
4,449 Wh
• No cooling vents are permitted with the
excepting of vents to disperse H2 gas created
while charging lead acid batteries

62. Battery Rules
• All high voltage equipment must be fully
enclosed and shut off from inside the
enclosure by a contactor.

63. A123 Batteries
• 26650
mjUltra Electrode
2000 W/kg
• 20Ah Prismatic Cell
mjHD Electrode
5200 W/kg

64. Power Available vs. Weight

65. 20Ah Prismatic 3.3V Cell
• 480g per cell (1.06lb)
• 2500W of power per cell
• 40 cells x 2500W = 100,000W @ 132V
• 100kW is equivalent to 135hp
• Capable of providing 750-800A
• After thermal and transmission loses at peak
torque, these batteries could support 60-70hp
of mechanical power at the wheels

67. Electrical Cooling Circuit

69. Battery Cooling Suggestion
• 40 Batteries
• 42lb Battery Weight
• 10.7lb of Coolant
• 4.8L of Coolant

71. Battery Cooling Suggestion
• 40 Batteries
• 42lb Battery Weight
• 8.1lb of Coolant
• 3.6L of Coolant

73. Battery Cooling Suggestion

74. A123 Battery Pack

75. A123 Battery Pack

77. Controls

79. HV Controls
• One Individual Kelly Controller per motor
• One contactor per motor

80. HV Controls
• Kelly Controller
- manages all regenerative braking power
circuits
- weight: 7lb
- 400A for 60sec
- 200A Continuous
- $999.00

81. Computers
• Supervisory Computer
– runs dash screen
– Supervision of entire electrical system and engine
– Controls safety features and backup systems
– Data logging
• Control Computer
– manages AWD system, and throttle attenuation

82. Supervisory Computer
• Monitors Current and RPM for all three
motors through CAN/RS232 BUS
• Monitors Electronic Cooling system
temperature – controls pump
• Monitors battery state of charge transmitted
by BMS
• Monitors Engine RPM, Temperature.
• Monitors Throttle, Brake, Steering Angle
through BUS from control computer

83. Supervisory Computer
• Can log any of the listed inputs when needed.
• Extra analog ports should be kept available for
future systems

84. Supervisory Computer
• Controls all motor contactors in parallel with
safety kill circuits.
– Will deactuate motors in case of partial system
failure of system overload.
• Controls amount of charging required to keep
batteries at safe level of charge
• Alert driver of any abnormalities and will
automatically manage/compensate power
train unless manually overwritten

85. Control Computer
• The Purpose of the Control Computer is to
supervise various inputs and attenuate the
electric motors according to torque
requirements and virtually differentiate wheel
speeds throughout power range.

86. Control Computer
• Inputs used for managing the AWD system for
this years competition include:

87. Control Computer
• Inputs used for managing the AWD system this
years competition include:
– 1x Steering Angle Sensor
– 1x Rear Axle Speed Sensor (signal of rear electric
motor)
– 1x Brake Potentiometer
– 1x Throttle Sensor (TPS)
– 1x Torque Bias Control Knob

89. Control Protocol
• Steering angle sensor will reference
Ackermann curve for approximant
differentiation and virtual turning radius.
• Slip angle bias due to lateral acceleration can
be estimated by steering angle related to a
certain speed.

92. Control Protocol
y = 0.0002x2 + 0.2x + 5
y = -0.0002x2 + 0.2x - 5
-50
-40
-30
-20
-10
0
10
20
30
40
50
-150 -100 -50 0 50 100 150
WheelAngle
Steering Wheel Angle
Ackermann induced by Steering Angle
R Wheel θ0
L Wheel θ0
Poly. (R Wheel θ0)
Poly. (L Wheel θ0)

93. Control Protocol
Torque Bias Knob will act as a multiplier
If the car understeers, increase the amount of
torque bias to the outside wheel
If the car oversteers, increase the amount of
torque bias onto the inside wheel
The Amount of Torque Bias will be calculated
the same for acceleration and deceleration

96. Overall Concept