BatteriesUTA F11 Hybrid Preliminary Design Presentation and Concepts

BatteriesUTA F11 Hybrid Preliminary Design Presentation and Concepts

BatteriesUTA F11 Hybrid Preliminary Design PresentationUTA F11 Hybrid Preliminary Design Presentation and Concepts

byTobias OverdiekJune 29, 2010

byTobias OverdiekJune 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

BatteriesUTA F11 Hybrid Preliminary Design Presentation and Concepts

Batteries

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

CompetitionCompetition Points

Rear Drive Motor

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.

Top Mounted Motor

Side Mounted Motor

Side Mounted Motor

0 10 20 30 40 50 60 70 80 90 100

-20

0

20

40

60

80

100

120Throttle Actuation vs. Rear Motor/Engine

EngineMotor GeneratingMotor under Power

Throttle Actuation (%)

Pow

er O

utpu

t (%

)

0 10 20 30 40 50 60 70 80 90 1000

20

40

60

80

100

120

140

160

180

200

Throttle Actuation acting on all Drives- Hybrid Mode -

Rear Axle CombineFront Axle - UnattenuatedFront Attenuated

Throttle Actuation (%)

Pow

er O

utpu

t (%

)

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.

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.

Front Wheel Motors

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

Kit Brushless DC MotorsParker K Series

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.

Kit Brushless DC MotorsParker 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

Kit Brushless DC MotorsParker 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.

0 20 40 60 80 100 120 140 160 180 2000

500

1000

1500

2000

2500

3000

3500

4000

Heat Loss vs. Torque of various Motors

06210 at TP 03014 at TP04512 at TP06211 at TP06212 at TP

Motor Output Torque (Nm)

Heat

Loss

(W)

0 50 100 150 200 2500

500

1000

1500

2000

2500

3000

3500

4000

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

Torque generated at Wheel (Nm)

Heat

Loss

(W)

Batteries

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

Battery Rules

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

A123 Batteries

• 26650 mjUltra Electrode2000 W/kg

• 20Ah Prismatic Cell mjHD Electrode5200 W/kg

Power Available vs. Weight

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

Electrical Cooling Circuit

Battery Cooling Suggestion

• 40 Batteries• 42lb Battery Weight• 10.7lb of Coolant• 4.8L of Coolant

Battery Cooling Suggestion

• 40 Batteries• 42lb Battery Weight• 8.1lb of Coolant• 3.6L of Coolant

Battery Cooling Suggestion

A123 Battery Pack

A123 Battery Pack

Controls

HV Controls

• One Individual Kelly Controller per motor• One contactor per motor

HV Controls

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

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

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

Supervisory Computer

• Can log any of the listed inputs when needed.• Extra analog ports should be kept available for

future systems

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

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.

Control Computer

• Inputs used for managing the AWD system for this years competition include:

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

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.

Control Protocol

-150 -100 -50 0 50 100 150

-50

-40

-30

-20

-10

0

10

20

30

40

50

f(x) = − 0.000222222222222222 x² + 0.2 x − 5

f(x) = 0.000222222222222222 x² + 0.2 x + 5

Ackermann induced by Steering Angle

R Wheel θ0Polynomial (R Wheel θ0)L Wheel θ0Polynomial (L Wheel θ0)

Steering Wheel Angle

Whe

el A

ngle

Control Protocol

Torque Bias Knob will act as a multiplierIf the car understeers, increase the amount of torque bias to the outside wheelIf 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

Overall Concept