Electrical PresentationJordan Morris (MASc)

Eric Evenchick (BASc)

UWAFT Vehicle Powertrain

2.4 L LE9

E85

GK

N 9

.59

:1

Battery

Charger

Fuel

Tank

TM4 105 kW

Motor (Front)

A123 18.9 kWh

ESS

TM4 105 kW

Motor (Rear)

GK

N 7

.47

:1

TM4 105 kW

Generator

2:1

Be

lt D

rive

Electric Hybrid

Mechanical

ConnectionElectrical

Connection

Single-Speed

Gear ReductionFuel

Connection

Legend

Component Specification

Engine: GM

2.4L LE9 Flex

Fuel

Peak

Efficiency37%

Peak Power131 kW @

5800 rpm

Peak Torque230 Nm @

5000 rpm

ESS: A123

Systems Inc.

7 Module,

15s3p

Voltage 340 V

Energy 18.9 KWh

Peak Power 177 kW

Motor/

Generator:

TM4 MOTIVE

Peak/Cont.

Power105 – 54 kW

Peak/ Cont.

Torque180 – 70 Nm

Voltage

Range320 – 450 V

Final Drives:

GKN Driveline

Front Ratio 7.47:1

Rear Ratio 9.59:1

Charger:

Brusa NL513

Peak Power 3.3 kW

Typical

Efficiency93%

UWAFT VTS

Metric Design Target Requirement Actual

0-60mph (s) 9.5 11.5 6.8

50-70mph (s) 8.0 10 3.1

Top Speed (km/h) NA 120 151

60-0mph (m) 43.7 54.8 50

Vehicle Mass (kg) <2250 2250 2078

Vehicle Range (km) 322 322 400

EV Range (km) NA NA 42

Fuel Consumption (L/100km) 7.12 NA 4.34

WTW GTG Emissions (g GHG/km) 204 NA 169.3

Criteria Emissions T2 B5 T2 B5 T2 B5

General Fuse/Wire SelectionFuse Selection Considerations:

• Nominal Operating Current• Ambient Temperature• Overload Conditions and Opening

Times• Available Short Circuit Current• Melting Integral• Pulse and Inrush Characteristics• Characteristics of Protected Equipment• Physical Size• Standard Requirements

Wire Selection Considerations:

• Ensure wires are compatible with SAE J1127 and J1128 standard

• Peak Current Draw• Wire Length• Ambient Temperature

Wire Margins:

In General: Fuse is selected based on component characteristicsWire is selected based on fuse characteristics

• For LV systems:• For HV system cables selected

based on manufacturer recommendations

Fuse De-Rating Example (Generator)

Fuse De-Rating Calculations

• Typical under hood temperature can reach 100OC• Inside distribution box can reach 60OC• for motor is 169A

Derating Factor Symbol Value

Max Permissible Current 𝐼𝑏 180

Rated Current for Given Fuse 𝐼𝑛 225

Ambient Temperature 𝑘𝑇 0.8

Thermal Correction Factor 𝑘𝑒 ~1

Cooling Air Correction Factor 𝑘𝑣 1

Frequency Correction Factor 𝑘𝑓 ~1

Correction for High Altitude 𝑘𝑎 1

I2T Analysis Front Cooling Loop• Includes pump and fan• Fuse Rating = 20 A• Lightning pulse characteristic• Melting I2T = 520 A2S• Pulse I2T = 227.40768• Based on these calculations fuse was replaced

with 25 A fuse to limit nuisance fuse blows

ComponentPulse Peak

(A)0.5t (s) I2T

Rated Fuse (A) Melting I2T

% of Melting Condition

Fuse cycle Life1

Generator 12V 1 0.3 0.216 10 115 0.19 >100,000

Front Motor 12V 1 0.3 0.216 10 115 0.19 >100,000

Rear Motor 12V 1 0.3 0.216 10 115 0.19 >100,000

Front Cooling Loop 28.1 0.4 227.407 25 1080 21.06 >100,000

Clutch 15 0.2 32.4 15 340 9.53 >100,000

AC Compressor 12V 9 0.15 8.748 10 115 7.61 >100,000

BMS 12V 9.5 0.5 32.49 15 340 9.56 >100,000

Rear Cooling Loop 22 0.35 121.968 20 520 23.46 10k - 100k

DCDC Fan 4 0.2 2.304 5 26 8.86 >100,000DCDC LV Side N/A N/A N/A N/A N/A N/A N/A

GKN Park Lock 35 0.25 220.5 30 1510 14.60 >100,000

HVIL Supply 1.5 0.5 0.81 5 26 3.12 >100,000Dampers 3 0.15 0.972 5 26 3.74 >100,000

Fuse Cycle Life UWAFT Added Components

1. http://www.littelfuse.com/~/media/electronics/product_catalogs/littelfuse_fuse_catalog.pdf.pdf page 15

Load Accommodation and EfficiencyLoad Type Peak (UWAFT added) Load (A)

Nominal LV Load 52

Nominal LV Load with PHCC 152

Peak LV Load 113

Peak LV Load with PHCC 233

• GM APM connects 18.9 kWh HV battery to 480 Wh LV battery

• Additional loads are only activated when required• Pre-heated catalytic converter runs

less than 5 minutes

LV Parasitic Current

• Stock GM system has low parasitic draw, but must crank engine• UWAFT has higher current draw, but no LV engine crank• Why so high? Still running rapid prototyping tools

• For production remove controllers and development tools

System Stock UWAFT

Parasitic Current Draw (mA) 50 200

2 week Energy Drain (Ah) 16.8 67.2

12V Battery Capacity (Ah) 40 40

Vehicle No-Start Battery Voltage (V)

10.5 9.5

Time to No Start (weeks) 4.75 1.2

HV Bus Voltage/Current Ripple• Portion of drive cycle, stop and go traffic with CAN data• Max speed = 60 km/h• Max battery current = 115 A• Max battery power = 38 kW

HV Bus Voltage/Current Ripple: 40s window

MeasuredParameter

Sampling Rate

Peak-to-peakripple

Voltage 100 kHz 1

Current 10 kHz 8

Battery Current Draw

Battery Voltage

• Voltage measurements taken with ETAS HV sensors connected to HV Test port in rear distribution box

• Current measurements taken with hall effect sensor connected to ETAS LV sensors

HV Bus Voltage/Current Ripple: 400 ms window

• 200 Hz low pass filter shows ripple low frequency ripple of ~60 Hz on DC bus

• This ripple can be attributed to long and short term transients from battery

Battery Voltage

Battery Current

HV Bus Voltage/Current Ripple: 4ms window

• 1 kHz low pass filter shows 1.5 kHz ripple, likely a result of electric motor frequency

• Unfiltered component shows pulses at 38 kHz which agrees with 2 inverters switching between 16 and 20 kHz each

Battery Voltage

HV Bus Voltage/Current Ripple

Summary

No apparent resonance issues• TM4 input filters with X & Y capacitors limit resonance &

EMI/EMC issues

No resonance found in simulations• Year 2 simulations show gain = 1.3 around 4-5 kHz

Based on these findings, UWAFT decided no design changes were necessary

HV Bus Charge and Discharge Times

HV Bus Charge

HV Bus Discharge

• No engine start: motors are readily available, key-on to start time < 2 seconds

• At key off contactors opens and TM4 inverters discharge HV bus

• Bus capacitance = 1.875 mF

HV Safety and ServiceabilityE-Stops LED Indicators

HV Warning Labels

Safe Vehicle Servicing

HV Safety and Serviceability: Fault Detection

Challenge: Cable Routing

Challenge: Relay Control/Wiring

Front Relay Board Rear Relay Board

Generator Rear Traction Motor

Front Traction Motor BMS

Front Cooling Loop Rear Cooling Loop

Clutch DCDC Fan

HVAC Park Lock

HVIL1 HVIL Power

HVIL2 HVIL3

• Each relay requires a digital output pin• To reduce wiring and free up pins on controller, CAN controlled

relay boards were implemented• Based on Freescale S08D microcontroller

UWAFT Added Relay Components

Knowledge Transfer

Access to ToolsPartnership with Altium. Provides on-demand licenses for UWAFT team members

Central Repository New students can access all EcoCAR and EcoCAR2 documents

Mentorship Program Pairs new students with senior members

Safety TrainingAll students get basic high-voltage training before working on the car

QUESTIONS