2019 Formula Hybrid Electrical System Form 2 (ESF-2

2019 Formula Hybrid ESF-2 (Rev 1) i

2019 Formula Hybrid Electrical System Form 2 (ESF-2)

INTRODUCTION

The goal of the ESF is to ensure that vehicles are as safe as possible, and that they comply with the Formula-Hybrid completion rules. The ESF is divided into fourteen main sections:

1. System Overview 2. Operating Voltage 3. Safety Circuit 4. TSMP 5. Cables & Fusing 6. Motors 7. Isolation & Insulation 8. IMD 9. AMS 10. Accumulator & Container 11. Pre-Charge & Discharge 12. Torque Control 13. GLV 14. Charger

A clear, concise ESF will help you to build a better car. It will also help you to pass tech testing as most common tech problems can be addressed before the car reaches the track.

IMPORTANT INSTRUCTIONS AND REQUIREMENTS Read carefully!

1. Every part of this ESF must be filled with content. If a section is not relevant to your vehicle, mark it as “N/A” and describe briefly why not.

2. Please leave the written instructions in place and add your responses below them. 3. All figures and tables must be included. An ESF with incomplete tables or figures will be

rejected. 4. The maximum length of a complete ESF is 100 pages. 5. Note that many fields ask for information that was submitted in your ESF-1. This information

must be reentered – in some cases will be different than what was entered in ESF-1, which is OK.

6. Submit this document in Word format – do not convert it to PDF! Submit to: http://formula-hybrid.com/uploads/

http://formula-hybrid.com/uploads/

2019 Formula Hybrid ESF-2 (Rev 1) ii

ESF-2 REVIEW PROCESS Feedback on your ESF occurs through both your team’s Google Doc and the FH ticket system at: http://formula-hybrid.com/level2/support/ Your ESF will be reviewed by a team of “section reviewers” - experts in specific areas of the FH rules. Reviewers will add comments coded with “//” for an informational comment, or “!!!” indicating that more information is needed, or that a concern is raised, for example: // This diagram is well done. A suggestion in future would be to … !!! We have a concern regarding your accumulator construction - how did you calculate required fuse capacity? No action is required for informational (//) comments. (!!!) comments require action - either by responding to the comment in the Google doc, or opening a rules ticket (and adding a response, e.g., “See FH Ticket 1234 for resolution”. When a (!!!) comment is resolved, you or the inspector involved may indicate this with a final comment: // RESOLVED // If you have not received a response to a critical Google doc question, please open a follow-up ticket at: http://formula-hybrid.com/level2/support/

The ESF2 is a tool which was created to improve the probability that your vehicle will pass the electrical inspections on its first try. It is up to you and your team to follow up on all open items.

http://formula-hybrid.com/level2/support/

http://formula-hybrid.com/level2/support/

2019 Formula Hybrid ESF-2 (Rev 1) iii

TITLE PAGE

Please include team logo, car picture, etc..

University Name: Lafayette College

Team Name: Lafayette Motorsports

Car Number: 204 Main Team Contact for ESF related questions:

Name: Hayden Dodge

e-mail: [email protected]

2019 Formula Hybrid ESF-2 (Rev 1) iv

Table of Contents

INTRODUCTION ............................................................................................................................ i

TITLE PAGE ...................................................................................................................... iii

I List of Figures ............................................................................................................ vi

II List of Tables ............................................................................................................. vii

III List of Abbreviations ............................................................................................... viii

Vehicle Overview ........................................................................................... 1

Operating Voltage .......................................................................................... 7

Safety Circuit .................................................................................................. 8

3.1 Shutdown Circuit ................................................................................................................. 8 3.2 Shutdown System Interlocks ............................................................................................. 12

Indicator Operation ...................................................................................... 13

4.1 Tractive System Active Lamp (TSAL) ............................................................................... 13 4.2 Safety Systems OK Lamp (SSOK) ................................................................................... 14 4.3 Ready-To-Drive-Sound (RTDS) ........................................................................................ 14

TSMP ............................................................................................................. 16

5.1 Tractive System Measurement Points (TSMP) ................................................................. 16

Cables & Fusing ........................................................................................... 17

6.1 Fusing & Overcurrent Protection ....................................................................................... 17 6.2 Component Fusing ............................................................................................................ 17 6.3 System Wire Tables .......................................................................................................... 19

Motors ........................................................................................................... 20

7.1 Motor(s) ............................................................................................................................. 20 7.2 Motor Controller ................................................................................................................ 20

Isolation & Insulation .................................................................................. 22

8.1 Separation of Tractive System and Grounded Low Voltage System ................................ 22 8.2 Grounding System ............................................................................................................ 23 8.3 Conductive Panel Grounding ............................................................................................ 23 8.4 Isolation ............................................................................................................................. 23 8.5 Conduit .............................................................................................................................. 24

2019 Formula Hybrid ESF-2 (Rev 1) v

8.6 Shielded dual-insulated cable ........................................................................................... 25 8.7 Firewall(s) ......................................................................................................................... 25 Description/materials ................................................................................................................... 25

Printed Circuit Boards ................................................................................. 27

IMD ............................................................................................................. 28

10.1 IMD ................................................................................................................................... 28 10.2 Reset / Latching for IMD and AMS ................................................................................... 29

AMS ........................................................................................................... 31

11.1 Accumulator Management System (AMS) ........................................................................ 31

Accumulator and Container .................................................................... 33

12.1 Accumulator Pack ............................................................................................................. 33 12.2 Cell description ................................................................................................................. 34 12.3 Cell configuration .............................................................................................................. 34 12.4 Segment Maintenance Disconnect ................................................................................... 35 12.5 Lithium-Ion Pouch Cells .................................................................................................... 35 12.6 Cell temperature monitoring .............................................................................................. 36 12.7 Accumulator Isolation Relays (AIR) .................................................................................. 36 12.8 Accumulator wiring, cables, current calculations .............................................................. 37 12.9 Accumulator indicator ....................................................................................................... 38 12.10 Accumulator Container/Housing .................................................................................... 38 12.11 HV Disconnect (HVD) .................................................................................................... 40

Pre-charge / Discharge ............................................................................ 42

13.1 Pre-Charge circuitry .......................................................................................................... 42 13.2 Discharge circuitry ............................................................................................................ 45

Torque Control .......................................................................................... 50

14.1 Accelerator Actuator / Throttle Position Sensor ................................................................ 50 14.2 Accelerator / throttle position encoder error check ........................................................... 51

GLV ............................................................................................................ 53

15.1 GLV System Data ............................................................................................................. 53

Charger ...................................................................................................... 54

16.1 Charging ........................................................................................................................... 54

Appendices ............................................................................................... 57

2019 Formula Hybrid ESF-2 (Rev 1) vi List of Figures

I List of Figures Figure 1 - Electrical System Block Diagram ...................................................................................... 3 Figure 2 - Drawing showing the vehicle from the top, side, and front ............................................... 4 Figure 3 - Locations of major TS components .................................................................................. 5 Figure 4 - TS Wiring Schematic ........................................................................................................ 6 Figure 5 - TS High Level Diagram ..................................................................................................... 6 Figure 6 - Safety Shutdown Circuit Schematic .................................................................................. 8 Figure 7 - Location of Shutdown Circuit Components ..................................................................... 11 Figure 8 - Shutdown State Diagram (if non-standard) ..................................................................... 12 Figure 9 - Tractive System Active Lamp (TSAL) Powering Circuitry ............................................... 13 Figure 10 - Ready To Drive Sound Control Circuitry ....................................................................... 14 Figure 11 - TSI Drive State Diagram ............................................................................................... 15 Figure 12 - TS and GLV separation in Accumulator Packs ............................................................. 22 Figure 13 - Team Designed PCB Layout ........................................................................................ 23 Figure 14 - Firewall Locations ......................................................................................................... 26 Figure 15 - TSI PCB ........................................................................................................................ 27 Figure 16 - IMD Relay on TSI PCB ................................................................................................. 28 Figure 17 - IMD Fault Light Driving Circuitry ................................................................................... 29 Figure 18 - TS Bus Bar between Cells ............................................................................................ 37 Figure 19 - High Voltage Indicator ................................................................................................... 38 Figure 20 - Accumulator Container Details ..................................................................................... 40 Figure 21 - HVD Accumulator Pack Locations ................................................................................ 41 Figure 22 - Pre-charge Circuit ......................................................................................................... 42 Figure 23 - Pre-charge Circuit Voltage, Current, & Power Analysis ................................................ 44 Figure 24 - Discharge Circuit ........................................................................................................... 45 Figure 25 - Discharge Circuit Voltage, Current, & Power Analysis ................................................. 47 Figure 26 - Discharge Resistor Drawing ......................................................................................... 48 Figure 27 - TSI Throttle Isolation Circuit .......................................................................................... 51 Figure 28 - Throttle Plausibility Circuit ............................................................................................. 52 Figure 29 - Charging Circuit with fusing – SegMan Schematic ....................................................... 55

Must be hyperlinked!

2019 Formula Hybrid ESF-2 (Rev 1) vii List of Tables

II List of Tables Table 1- General Electrical System Parameters ............................................................................... 7 Table 2 - Switches & devices in the shutdown circuit ........................................................................ 9 Table 3 - Shutdown circuit Current Draw ........................................................................................ 10 Table 4 - TSMP Resistor Data ........................................................................................................ 16 Table 5 - Fuse Table ....................................................................................................................... 17 Table 6 - Component Fuse Ratings ................................................................................................ 18 Table 7 - System Wire Table ........................................................................................................... 19 Table 8 - Motor Data ....................................................................................................................... 20 Table 9 - Motor Controller Data ....................................................................................................... 21 Table 10 - Purchased Components ................................................................................................. 23 Table 11 - List of Containers with TS and GLV wiring ..................................................................... 24 Table 12 - Insulating Materials ........................................................................................................ 24 Table 13 - Conduit Data .................................................................................................................. 24 Table 14 - Shielded Dual Insulated Cable Data .............................................................................. 25 Table 15 - PCB Spacings ................................................................................................................ 27 Table 16 - Parameters of the IMD ................................................................................................... 28 Table 17 - AMS Data ....................................................................................................................... 31 Table 18 - Main accumulator pack parameters ............................................................................... 33 Table 19 - Main cell specification .................................................................................................... 34 Table 20 - SMD Data ....................................................................................................................... 35 Table 21 - Cell Temperature Monitoring .......................................................................................... 36 Table 22 - AIR data ......................................................................................................................... 37 Table 23 - Data for the pre-charge resistor ..................................................................................... 44 Table 24 - Data of the pre-charge relay .......................................................................................... 45 Table 25 - Discharge Resistor data ................................................................................................. 47 Table 26 - Throttle Position encoder data ....................................................................................... 50 Table 27 - GLV System Data .......................................................................................................... 53 Table 28 - Charger data .................................................................................................................. 56

Must be hyperlinked!

2019 Formula Hybrid ESF-2 (Rev 1) viii List of Abbreviations

III List of Abbreviations AIR Accumulator Isolation Relay AMS Accumulator Management System BOTS Brake Over-Travel Switch BRB Big Red Button CellMan Cell Manager FH Rules Formula Hybrid Rule GLV Grounded Low-Voltage GLVMS Grounded Low Voltage Master Switch. IMD Insulation Monitoring Device MC Motor Controller PackMan Pack Manager RTDS Ready To Drive Sound SegMan Segment Manager SMD Segment Maintenance Disconnect SSOK Safety Systems OK TS Tractive System TSAL Tractive System Active Light TSI Tractive System Interface TSMP Tractive System Measurement Point TSMS Tractive System Master Switch. TSV Tractive System Voltage (V)SCADA (Vehicular) Supervisory Control and Data Acquisition (Add additional abbreviations or acronyms specific to your diagrams or schematics)

2019 Formula Hybrid ESF-2 (Rev 1) 1 Vehicle Overview

Vehicle Overview Person primarily responsible for this section:

Name: David Sadvary

e-mail: [email protected] Check the appropriate boxes: Vehicle is New (built on an entirely new frame)

New, but built on a pre-existing frame Updated from a previous year vehicle

Architecture

Hybrid

Series

Parallel

Hybrid in Progress (HIP1)

Electric-only

Drive

Front wheel

Rear wheel

All-wheel

Regenerative braking

Front wheels

Rear wheels

None

1 HIP does not need to be declared prior to the competition. If unsure, check “Hybrid”


NARRATIVE OVERVIEW Provide a brief, concise description of the vehicles main electrical systems including tractive system, accumulator, hybrid type (series or parallel) and method of mechanical coupling to wheels. Describe any innovative or unusual aspects of the design. The tractive system operates nominally on 90 VDC provided by two removable battery packs for a total capacity of 60 Ah. Each pack contains fourteen 3.2V LiFeMnPO4 cells in series monitored by an in-house accumulator management system featuring active cell balancing between each segment of seven cells. The tractive system interface (TSI) provides an interface between GLV and TS components including management of drive states, TS pre-charge and discharge, throttle error checking, control of the cooling system, variety sensors, and the insulation monitoring device. A single Emrax 208 DC permanent magnet motor is driven by an Emsiso emDrive 500 motor controller. Power from the motor is delivered through a drive belt to the drivetrain where it is then distributed through a Drexler Formula Student Limited Slip differential to a CV axle in each half shaft. The Vehicular Supervisory Control and Data Acquisition system is cable of communicating with all electrical subsystem for unified data collection and real time analysis. Include the following figures:

• Figure 1 – an electrical system block diagram showing all major parts associated with the tractive-system. (Not detailed wiring).

• Figure 2 – Drawings or photographs showing the vehicle from the front, top, and side

• Figure 3 – A wiring diagram superimposed on a top view of the vehicle showing the locations of all major TS components and the routing of TS wiring.

• Figure 4 -- A complete TSV wiring schematic per FH Rule EV13.2.1 showing connections between all TS components.

This should include:

o Accumulator Cells o AIRs o SMDs o Fuses o Wire Gauges o Motor controller o Motor o Pre-charge and discharge circuits o AMD o IMD o Charging port


o Any other TS connections.

IMPORTANT NOTICE When pasting drawings and schematics into the provided boxes, be

certain that the graphics in the files are at a high enough resolution that the smallest details can be examined by enlarging the files.

Figure 1 - Electrical System Block Diagram


Figure 2 - Drawing showing the vehicle from the top, side, and front


Figure 3 - Locations of major TS components (PDF)

https://sites.lafayette.edu/motorsports/files/2019/03/TS-Wiring-Overlay-Views.pdf#page=1




Figure 4 - TS Wiring Schematic (PDF)

Figure 5 - TS High Level Diagram

(PDF)

https://sites.lafayette.edu/motorsports/files/2019/02/Car_2019_v3.04.pdf

https://sites.lafayette.edu/motorsports/files/2019/02/TSHighLevel.pdf

https://sites.lafayette.edu/motorsports/files/2019/02/Car_2019_v3.04.pdf

https://sites.lafayette.edu/motorsports/files/2019/02/TSHighLevel.pdf

2019 Formula Hybrid ESF-2 (Rev 1) 7 Operating Voltage

Operating Voltage Person primarily responsible for this section:

Name: Katherine Lee

e-mail: [email protected] Fill in the following table:

Item Data

Nominal Tractive System Voltage (TSVnom) 89.6 VDC

Maximum Tractive System Voltage (TSVmax) 100.0 VDC

Control System Voltage / Grounded Low Voltage system (GLV) 24.0 VDC

Table 1- General Electrical System Parameters

2019 Formula Hybrid ESF-2 (Rev 1) 8 Safety Circuit

Safety Circuit Person primarily responsible for this section:

Name: Max McFarlane


3.1 Shutdown Circuit

Include a schematic of the shutdown circuit for your vehicle including all major components in the loop

Figure 6 - Safety Shutdown Circuit Schematic (PDF)

Describe the method of operation of your shutdown circuit, including the master switches, shut down buttons, brake over-travel switch, etc. Also complete the following table The GLV Master Switch and BRB’s shutdown the entire system. The IMD, AMS, and SCADA systems all control relays capable of breaking the safety loop. The brake over-travel switch also breaks the safety loop when switched. When the safety loop is broken, current is stopped from energizing the AIRs and the TS is discharged. The Master Reset pushbutton must be pressed while there are no system faults to latch the Master Reset relay and allows the safety loop to continue to be closed. The Master Reset relay will remain closed unless the safety loop is broken by a device that occurs prior to Master Reset. Since the Master Reset pushbutton is not accessible by the driver, any fault that breaks the safety loop before the Master Reset is non-driver resettable. After the Master Reset, the cockpit safety switches must be closed by the driver. This includes resetting the Cockpit BRB and pressing Cockpit Reset pushbutton. When the Cockpit Reset

https://sites.lafayette.edu/motorsports/files/2019/02/Safety-Loop_v5.pdf

https://sites.lafayette.edu/motorsports/files/2019/02/Safety-Loop_v5.pdf


pushbutton is pressed, the Cockpit Reset relay is closed. The Cockpit BRB and Cockpit Reset pushbutton are the only safety loop elements that are driver accessible. The TSV Master Switch is the last switch before power is provided to the AIRs and the discharge relay. Various points of the safety loop are monitored by the VSCADA system. This allows for technicians to quickly identify breaks in the safety loop during debugging.

Part

Function (Momentary, Normally Open or Normally Closed)

Grounded Low Voltage Master Switch (GLVMS)

Normally Open, Latching Switch

Shutdown buttons (BRB) Normally Closed

Insulation Monitoring Device (IMD) Normally Open

Accumulator Management System Relay (AMS Relay)

Normally Open

Brake over-travel switch (BOTS) Normally Closed

SCADA Relay Normally Closed (reconfigurable)

Master Reset Pushbutton Normally Open, Momentary

Master Reset Relay Normally Open

Cockpit Reset Pushbutton Normally Open, Momentary

Cockpit Reset Relay Normally Open

Tractive System Master Switch (TSMS) Normally Open, Latching Switch

Interlocks (if used) N/A

Table 2 - Switches & devices in the shutdown circuit

Describe wiring and additional circuitry controlling AIRs. Write a functional description of operation When the TSMS is closed and the rest of the safety loop is closed, 24 V will be present between the AIRs+ and AIRs-. This will open the discharge relay and close the AIRs allow TSV outside the accumulator packs. The current requirements of the safety loop while running the AIRs is below in Table 3 - Shutdown circuit Current Draw.


Note: The AIRs require a 1.6 A pick up current in order to close the main contactor. The total peaking current for the safety loop is 6.91 A.

Total Number of AIRs: 4

Coil holding current per AIR: 0.10 A

Current drawn by other components wired in parallel with the AIRs. 0.60 A

Total current in shutdown loop: 1.00 A

Table 3 - Shutdown circuit Current Draw

Provide CAD-renderings showing the shutdown circuit parts. Mark the parts in the renderings


Figure 7 - Location of Shutdown Circuit Components


If your shutdown state diagram differs from the one in the Formula Hybrid rules, provide a copy of your state diagram (commented as necessary). N/A

Figure 8 - Shutdown State Diagram (if non-standard)

3.2 Shutdown System Interlocks (If used) describe the functioning and circuitry of the Shutdown System Interlocks. Describe wiring, provide schematics. N/A

2019 Formula Hybrid ESF-2 (Rev 1) 13 Indicator Operation

Indicator Operation Person primarily responsible for this section:

Name: Katherine Lee


4.1 Tractive System Active Lamp (TSAL) Describe the tractive system active lamp components and method of operation. Describe location and wiring, provide schematics. See EV9.1. The TSAL will be connected to the TS via the TSI. Once the AIRs are closed, the TSI will have TS voltage present. The voltage will pass through an isolated DC-DC converter on the TSI PCB to provide power to the TSAL lamps as shown in Figure XXX below. The DC-DC converter has an input operating range from 16 V to 160 V. The TSAL light will turn off when the TS voltage is below 16 V and turn on when the TSAL light is above 16 V. The TSAL will also flash at a rate of 2-3 Hz.

Figure 9 - Tractive System Active Lamp (TSAL) Powering Circuitry

(PDF)

Describe the Safety Systems OK Lamp components and method of operation. Describe location and wiring, provide schematics. See EV9.3 The SSOK Lamps are amber and comply with DOT FMVSS 108. They are mounted on the left and right side panels attached to the frame behind the drivers head. See figure X. The SSOK are powered by a 24V supply from the Safety Loop. Detailing of the safety loop wiring can be seen in Figure 6 - Safety Shutdown Circuit Schematic.

https://sites.lafayette.edu/motorsports/files/2019/03/TSI_schematic_0326-1.pdf#page=2



4.2 Safety Systems OK Lamp (SSOK) Describe the Safety Systems OK Lamp components and method of operation. Describe location and wiring, provide schematics. See EV9.3 The SSOK lamps are wiring into the safety loop. See Figure 6 - Safety Shutdown Circuit Schematic for their location in the startup sequence. These lamps are powered from 24V in the safety loop. The SSOK light will only be illuminated if there is GLV power, there are no faults in the system, and the Master Reset pushbutton has been pressed. If a fault occurs, the Master Reset pushbutton must be pushed again to re-illuminate the SSOK lamps. See Figure 7 - Location of Shutdown Circuit Components for the location of the SSOK lamps on the vehicle.

4.3 Ready-To-Drive-Sound (RTDS) Describe your design for the RTDS system. See EV9.2. The Ready-to-Drive-Sound is controlled by a microprocessor on the TSI board. When the conditions for entering drive mode are met, the microprocessor will play the ready to drive sound for a duration of 2 seconds as the vehicle enters drive mode.

Figure 10 - Ready To Drive Sound Control Circuitry

(PDF)




Figure 11 - TSI Drive State Diagram (PDF)

https://sites.lafayette.edu/motorsports/files/2019/03/DSFSM.pdf

https://sites.lafayette.edu/motorsports/files/2019/03/DSFSM.pdf

2019 Formula Hybrid ESF-2 (Rev 1) 16 TSMP

TSMP Person primarily responsible for this section:

Name: Tianyu Zhu


5.1 Tractive System Measurement Points (TSMP)

The TSMP must comply with FH Rule EV10.3. Describe the TSMP housing and location. Describe TSMP electrical connection point. The TSMPs are located on the high voltage side of the TSI enclosure. The GLV ground mounting point is also located on the high voltage side of the TSI enclosure. The TSMPs are shrouded 4 mm banana jacks that accept shrouded (sheathed) banana plugs with non-retractable shrouds. The TSMPs connect to the TSV positive and negative terminals incoming to the TSI enclosure through 10 kΩ current limiting resistors. The TSI Enclosure Wiring diagram shows the TSMPs in detail. (PDF)

TSMP Output Protection Resistor Value 10 kΩ

Resistor Voltage Rating 460 V

Resistor Power Rating 5 W

Table 4 - TSMP Resistor Data

https://sites.lafayette.edu/motorsports/files/2019/03/TSI-Enclosure-Wiring-Rev1.0.pdf

2019 Formula Hybrid ESF-2 (Rev 1) 17 Cables & Fusing

Cables & Fusing Person primarily responsible for this section:

Name: Drew Carleton


6.1 Fusing & Overcurrent Protection List data for Primary TS and GLV fuses (or circuit breakers) and cross-reference to schematic.

Mfg.

Fuse Part

Number

Cont. Rating

(A)

DC Voltage Rating

DC Interrupt Rating (A) Schematic reference-designators (ref-des)

TE Connectivity

W28-XQ1A-15

15 A 32 VDC 1 kA @ 32 VDC

GLV Battery Circuit Breaker (Figure 6 - Safety Shutdown Circuit Schematic)

TE Connectivity

W28-XQ1A-8 8 A 32 VDC 1 kA @ 32

VDC

GLV Subsystem Circuit Breaker (Figure 6 - Safety Shutdown Circuit Schematic)

Littelfuse Inc.

0477002.MXP 2 A 400

VDC 1500 A F1, F2 in TSI Enclosure (PDF)

Merson A3T300 300 A 160

VDC 50,000 AIC Main TS Fuse (Figure 5 - TS High Level Diagram)

Littlefuse Inc.

0326025.MXP 25 A 250

VDC 600 A @ 125 VDC

Fuse protecting balancing an charging circuitry

Table 5 - Fuse Table

6.2 Component Fusing List data sheet max fuse rating for each major component (e.g., motor controller, dc-dc converter, etc.) Ensure that the rating of the fuse used is ≤ the maximum value for the component

Component

Max Fuse Rating per data sheet

(A)

Conductor (Table 7

line number)

Installed Fuse

Rating (A) Fuse Part Number Notes



Table 6 - Component Fuse Ratings


6.3 System Wire Tables List wires and cables used in the Tractive System and the GLV system – (wires protected by a fuse of 1 A or less may be omitted.) Cable capacity is the value from FH Rules Appendix E (Wire Current Capacity).

Mfg. Part Number

Size AWG / mm2 Insulation Type Voltage Rating

Temp. Rating (C)

Current capacity

(A) 1

IEWC EXRAD2/0-XLEOBS 2/0 Irradiated cross-linked elastomer

600 V -70 to 150 300

2 WTW WT16-4 16 PVC 60 V -55 to 80 20 3 Prestolite 152077 20 HDPE 60 V -60 to 125 10 4 Olflex 221809 18 PVC 1000 V -25 to 90 14 5 Olflex 221612 16 PVC 1000 V -25 to 90 20 6 General Cable/Carol Brand C2410A.41.10 12 PVC 300 V -20 to 80 40 7 Southwire E46194 12 PVC 300 V -50 to 105 40 8 9

10 11 12 13 14 15 16

Table 7 - System Wire Table

(Add additional lines as required)

2019 Formula Hybrid ESF-2 (Rev 1) 20 Motors

Motors Person primarily responsible for this section:

Name: Hayden Dodge


7.1 Motor(s) Describe the motor(s) used. Copy and Paste additional tables if multiple motor types are used

Manufacturer and Model: Emrax Innovative E-Motors, EMRAX 208 Low Voltage

Motor type (PM, Induction, DC Brush) PM

Number of motors of this type used 1

Nominal motor voltage (Vrms l-l or Vdc) 125 VDC (maximum)

Nominal / Peak motor current (A or A/phase) Nom: 400 Arms / Peak: 800 Arms

Nominal / Peak motor power Nom: 20-32 kW / Peak: 80 kW

Motor wiring – conductor Table 7 Line Number:

Table 8 - Motor Data (datasheet)

Provide calculations for currents and voltages. State how this relates to the choice of cables and connectors used. The maximum voltage of the TS system is 100 VDC. The TS 2/0 AWG cable is rated to 600 VDC. The accumulators are fused at 300 A. The maximum current capacity of the TS 2/0 AWG cable is 300 A.

7.2 Motor Controller Describe the motor controller(s) used. Copy and Paste additional tables if multiple motor controller types are used.

https://sites.lafayette.edu/motorsports/files/2018/12/user_manual_for_emrax_motors.pdf

2019 Formula Hybrid ESF-2 (Rev 1) 21 Motors

Manufacturer Emsiso

Model Number emDrive 500

Number of controllers of this type used: 1

Maximum Input voltage: 125 VDC

Nominal Input Current (A) 0-800 A

Output voltage (Vac l-l or Vdc) 125 VDC

Isolation voltage rating between GLV (power supply or control inputs) and TS connections

250 V

Is the accelerator galvanically isolated from the Tractive System per EV3.5.7 & EV5.1?

Yes / No

Table 9 - Motor Controller Data (further motor controller documentation can be found here)

If the answer to the last question is NO, how do you intend to comply with EV3.5 (an external isolator is acceptable). N/A Provide calculations for currents and voltages. State how this relates to the choice of cables and connectors used. The maximum voltage of the TS system is 100 VDC. The TS 2/0 AWG cable is rated to 600 VDC. The accumulators are fused at 300 A. The maximum current capacity of the TS 2/0 AWG cable is 300 A.

https://sites.lafayette.edu/motorsports/motor-controller/

2019 Formula Hybrid ESF-2 (Rev 1) 22 Isolation & Insulation

Isolation & Insulation Person primarily responsible for this section:

Name: Drew Carleton


8.1 Separation of Tractive System and Grounded Low Voltage System Describe how the TS and GLV systems are physically separated (EV5.3). Add CAD drawings or photographs illustrating TS and GLV segregation in key areas of the electrical system. TSV is separated from GLV in the accumulator container by Garolite sheets. The cells are contained in a Garolite box. GLV is contained in the region shown to the right. The only wires that enter the TSV Garolite box from the GLV region are control wires for the AIRs and a two wired isolated-SPI interface. The SPI interface is galvanically isolated on the TSV and GLV side by transformers. The AIR control wiring is separated from TSV by routing the cables and securing with cable ties so that the minimum distance between GLV and TSV will be achieved.

Figure 12 - TS and GLV separation in Accumulator Packs

GLV region TSV region

(in Garolite Box)


8.2 Grounding System

Describe how you keep the resistances between accessible components below the required levels as defined in FH Rules EV8.1. If wire is used for ground bonding, state the AWG or mm2 of the wire. To ensure that we will have proper grounding to the chassis, we will be using 12 AWG wire for distributing the chassis ground. Each subsystem (TSV, TSI, Motor Controller, Cooling, GLV/VSCADA) will have its conductive components (such as the enclosure, shielded cables, conductive connectors, etc) connected to GLV ground using 12 AWG cables.

8.3 Conductive Panel Grounding If carbon fiber or coated conductive panels are used in your design, describe the fabrication methods used to ensure point to point resistances that comply with EV8.1.2. Describe results of

Figure 13 - Team Designed PCB Layout

List all purchased components that have connections to both TS and GLV

Component

TS/GLV Isolation

(V) Link to Document

Describing Isolation Notes

Table 10 - Purchased Components

8.4 Isolation Provide a list of containers that have TS and GLV wiring in them. If a barrier is used rather than spacing, identify barrier material used (reference Table 12 - Insulating Materials).

Container Name

Segregation by Spacing (Y or N)

How is Spacing

maintained

Actual Measured

Spacing mm Alt – Barrier Material P/N

Notes


Accumulator Container Y & N

barrier & cable routing

Unknown Garolite Pack is still be constructed. Unable to measure separation distance.

TSI Enclosure N Barrier N/A Garolite

Table 11 - List of Containers with TS and GLV wiring

List all insulating barrier materials used to meet the requirements of EV2.4.3 or EV5.4

Insulating Material / Part

Number

UL Recognized

(Y / N)

Rated Temperature

ºC Thickness

mm Notes

Garolite G-10 N 130 (265 ºF)

1.5875 (1/16 in)

Table 12 - Insulating Materials

8.5 Conduit List different types of conduit used in the design. Specify location and if manufacturer’s standard fittings are used. Note Virtual Accumulator Housing FH Rules EV2.12 requires METALLIC type LFMC. Describe how the conduit is anchored if standard fittings are not used. No conduit is used.

Conduit Type MFR

Part Number

Diameter Inch or

mm

Standard Fittings (Y or N) Location / Use

Table 13 - Conduit Data


Is all conduit contained within the vehicle Surface Envelope per EV3.1.6? (Y or N). Does all conduit comply with EV3.2? (Y or N).

8.6 Shielded dual-insulated cable If Shielded, dual-insulated cable per EV3.2.5(a) used in the vehicle, provide specifications and where used:

MFR Part

Number

Cross Section mm2

Shield grounded at

both ends (Y or N) Location / Use

IEWC

EXRAD2/0-XLEOBS

70 Y All external TS wiring between accumulator containers, TSI enclosure, Motor Controller, and Motor (Figure 3 - Locations of major TS components)

Table 14 - Shielded Dual Insulated Cable Data

8.7 Firewall(s) Description/materials Describe the concept, layer structure and the materials used for the firewalls. Describe how all firewall requirements in FH Rules T4.5 are satisfied. Show how the low resistance connection to chassis ground is achieved. The firewall is made from 1.5mm thick aluminum sheets mechanically bolted to steel mounting tabs welded to the frame. Each sheet is connected with one another with fire resistant tape to fully insulate the cockpit from all T4.5.1 components. The firewalls immediately shielding the cockpit are going to be mounted immediately outside of the tube structure in order to properly mount the vehicles seat and securely fasten the drivers harness without breaking the firewalls isolation. Furthermore, the accumulator packs are going to be completely isolated with side accumulator firewalls depicted in the side pods in Figure x. The main roll hoop height has been increased from previous year’s frame design. A higher main roll hoop ensures that the firewall is extended upwards behind the driver to a height where a straight line cannot be drawn between 150mm below the top of the tallest driver’s helmet and the electronic components behind the driver ensuring compliancy with T4.5.1. The chassis is connected to GLV ground using a 12 AWG cable. Since the firewalls and mechanical fasteners are conducting, the firewalls will be electrically connected to the chassis and thus grounded.


Position in car Provide CAD-rendering or photographs showing the location of the firewall(s).

Figure 14 - Firewall Locations

2019 Formula Hybrid ESF-2 (Rev 1) 27 Printed Circuit Boards

Printed Circuit Boards Person primarily responsible for this section:

Name: Katherine Lee

e-mail: [email protected] List all electrical circuit boards designed by team that contain TS and GLV voltage in the following table.

Device / PCB

TS Voltage Present

(V)

Minimum Spacing

mm

Thru Air of Over Surface Notes

TSI 96 10.160 OS

Table 15 - PCB Spacings

Add a figure (board layout drawing) for each team-designed PCB showing that spacings comply with EV5.5.

Figure 15 - TSI PCB

(PDF)

https://sites.lafayette.edu/motorsports/files/2019/03/TSI-2019-0304-PCB-layout1.pdf

https://sites.lafayette.edu/motorsports/files/2019/03/TSI-2019-0304-PCB-layout1.pdf

2019 Formula Hybrid ESF-2 (Rev 1) 28 IMD

IMD Person primarily responsible for this section:

Name: Katherine Lee


10.1 IMD Describe the IMD used and use a table for the common operation parameters, like supply voltage, temperature, etc. Describe how the IMD indicator light is wired. Complete the following table.

MFR / Model Bender IR155-3204

Set response value: 100 kΩ (1024 Ω/Volt)

Table 16 - Parameters of the IMD

Describe IMD wiring with schematics. The IMD is connected directly to the HV source within the TSI. It has 3 connections to GLV ground as well as one connection to the 24 V GLV. One connection goes to the IMD relay which is normally open. This relay has control over the safety loop. The last connection is the IMD_PWM signal from the microcontroller in the TSI. Refer to the TSI wiring diagram (PDF) for details regarding the IMD wiring.

Figure 16 - IMD Relay on TSI PCB

(PDF)





Figure 17 - IMD Fault Light Driving Circuitry

(PDF)

10.2 Reset / Latching for IMD and AMS Describe the functioning and circuitry of the latching/reset system for a tripped IMD or AMS. Describe wiring, provide schematics. The IMD will open the IMD relay to break the safety loop when an IMD fault is detected. When the OKHS (IMD High Side Status Output) signal is not producing the normal 24V during safe usage, the relay will open and will close once the IMD status returns to normal after rectifying the IMD fault. The AMS system will close the AMS relay when the reset conditions are met. This can be done automatically when the AMS detects this or by a non-drives in the battery pack interface. Even though the AMS fault is cleared and the relay is reset, the safety loop will not close and energize the AIRs until the Reset buttons are pushed. When the AMS, IMD or any other break prior to the Master Reset pushbutton breaks the safety loop, two reset buttons must be pushed to re-engage the AIRs. The Master Reset pushbutton is on the outside of the car and is not accessible by the driver. Thus an AMS or IMD fault will require a non-driver to re-energize the safety loop. After the Master Reset button has been pressed, the Cockpit Reset button must be pressed. The Cockpit Reset button is accessible by the driver. Pressing each reset energizes its relay that maintains the safety loop as long as long as the safety loop is unbroken prior to the relay. Refer to the safety loop diagram in Figure 6 - Safety Shutdown Circuit Schematic for a schematic of the wiring for the reset buttons.




See Figure 16 - IMD Relay on TSI PCB in Section 10.1 for more details about the IMD relay. (PDF) See the PackMan schematic for details about the AMS relay. (PDF) For more details about the reset relays, see the GLV Breakout Board schematic. (PDF)


https://sites.lafayette.edu/motorsports/files/2019/03/pacman_schematic.pdf

https://sites.lafayette.edu/motorsports/files/2019/03/GLV_BoB_rev4-1.pdf

2019 Formula Hybrid ESF-2 (Rev 1) 31 AMS

AMS Person primarily responsible for this section:

Name: Hayden Dodge


11.1 Accumulator Management System (AMS)

Manufacturer Lafayette College

Model Number TBD: Made In House

Number of AMSs 2

Upper cell voltage trip* 3.8 V

Lower cell voltage trip* 2.8 V

Temperature trip* 60 °C

Table 17 - AMS Data

*These trip points are reconfigurable in the AMS software and may change with additional testing on the packs.

• Describe how the AMS meets the requirements of EV2.11.

• Describe other relevant AMS operation parameters.

• Describe how many cells are monitored by each AMS board, the configuration of the cells,

the configuration of the boards and how AMS communications wiring is protected and

isolated.

• Describe how the AMS opens the AIRs if an error is detected

• Indicate in the AMS system the location of the isolation between TS and GLV

The Tractive System is powered by two accumulator packs each monitored by its own AMS system. Each AMS is made of three types of subsystems: the Pack Manager, PackMan; the

2019 Formula Hybrid ESF-2 (Rev 1) 32 AMS

Segment Manager, SegMan; and the Cell Manager, CellMan. (Note: Plural of CellMan is CellMen. Similar plural forms are used for the other AMS management boards.) The main AMS software is run on the PackMan board. The PackMan is responsible for all AMS functionality which includes:

• collecting cell temperatures, voltages, and discharge currents from the SegMen and CellMen,

• collecting the high voltage path discharge current

• controlling the AMS relay in the Safety Loop,

• determining State of Charge (SoC) on a cell, segment, and pack level,

• determining State of Health (SoH) of individual cells,

• determining when to actively balance cells within a segment,

• controlling the state of the charge port relay,

• interfacing with subsystems outside of the packs through the CAN bus,

• managing the user interface on the accumulator pack.

The PackMan is the only AMS board that contains a microprocessor. The PackMan microprocessor contains a watchdog timer that will reset the microprocessor when not fed. The SegMan is the isolated controller for an accumulator segment. The SegMan communicates with PackMan over an isolated SPI connection. The CellMan is mounted on top of each cell. The CellMan is mounted on top of bus bars which are the main current path. Each CellMan is able to measure the cell’s voltage, temperature, and the amount of current discharging from each cell. Additionally, the CellMan contains the transformer and power electronics needed to actively discharge a cell. Additionally, the CellMan contains a jumper that can be removed to allow the AMS system to be tested according to

2019 Formula Hybrid ESF-2 (Rev 1) 33 Accumulator and Container

Accumulator and Container Person primarily responsible for this section:

Name: Hayden Dodge


12.1 Accumulator Pack Provide a narrative design of the accumulator system and complete the following table. The accumulator system is comprised of two accumulator packs wired in series. The data in Table 18 - Main accumulator pack parameters is for one accumulator pack. Each pack has two segments of 7 cells. Each pack features active cell balancing for each segment. This allows one cell to be discharge and the energy redistributed among all cells in the segment. Cell balancing occurs on each segment independently.

Maximum Voltage (during charging): 56.0 VDC

Nominal Voltage: 44.8 VDC

Total number of cells: 14

Cell arrangement (x in series / y in parallel): 14 / 0

Are packs commercial or team constructed? Commercial / Team

Total Capacity (per FH Rules Appendix A2): 2.68 kWh

Maximum Segment Capacity 4.84 MJ

Number of Accumulator Segments 2 segments per pack

Table 18 - Main accumulator pack parameters

Describe how pack capacity is calculated. Provide calculation at 2C (0.5 hour) rate. How is capacity derived from manufacturer’s data? If so, include discharge data or graph here. Include Peukert calculation if used (See FH Rules Appendix A) Show your segment energy calculations. The segment energy is calculated as: 2 This includes an 80% derating for available traction energy


𝑉𝑉𝑉𝑉𝑉𝑉𝑉𝑉 𝑥𝑥 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 𝐴𝐴𝐴𝐴 (2𝐶𝐶 𝑟𝑟𝑟𝑟𝑟𝑟𝐶𝐶) 𝑥𝑥 𝑁𝑁𝑁𝑁𝑉𝑉𝑁𝑁𝐶𝐶𝑟𝑟 𝑉𝑉𝑜𝑜 𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶𝐶 𝑥𝑥 3.6 (𝑘𝑘𝑘𝑘)

(Note: The 80% factor is not applied for this calculation.)

12.2 Cell description Describe the cell type used and the chemistry and complete the following table. Cell Manufacturer AA Portable Power Corp.

Model Number LFP-G60

Cell type (prismatic, cylindrical, pouch, etc.) Yes / No

Are these pouch cells Yes / No

Cell nominal capacity at 2C (0.5 hour) rate: 50.3 Ah

Data sheet nominal capacity 60 Ah at 1C rate

Maximum Voltage (during charging): 3.8 V

Nominal Voltage (data sheet value): 3.2 V

Minimum Voltage (AMS setting): 2.8 V

Maximum Cell Temperature (charging - AMS setting) 60 °C

Maximum Cell Temperature (discharging - AMS setting) 60 °C

Cell chemistry: LiFeMnPO4

Table 19 - Main cell specification

IMPORTANT: Show your calculations here for 2C nominal AH capacity if the data sheet uses a different discharge rate. Refer to FH rules Appendix A

12.3 Cell configuration Describe cell configuration, show schematics, cover additional parts like internal cell fuses etc. Describe configuration: e.g., N cells in parallel then M packs in series, or N cells in series then M strings in series. There are two packs in series. Each pack contains two segments in series. Each segment contains 7 cells in series. This leads to a 60Ah 89.6 V nominal accumulator system. Does the accumulator combine individual cells in parallel without cell fuses? Yes / No


If Yes, explain how EV2.6.3 is satisfied.

12.4 Segment Maintenance Disconnect Describe segment maintenance disconnect (SMD) device, locations, ratings etc. There are 4 segments contained within two accumulator packs. The packs are separated by the HVD which forms a 3rd SMD. There is a SMD within each pack separating the two segments within each pack. The internal pack SMD is described in Table 20 - SMD Data. See Figure 5 - TS High Level Diagram for the location of the internal pack SMDs described below.

Is HVD used as an SMD? Yes / No

Number of SMD Devices / Number of Segments 2 / 4

SMD MFR and Model

Anderson Power Products Powerpole 180 Plated Bus Bar Contact Powerpole 180

SMD Rated Voltage (if applicable) 600 V

SMD Rated Current (if applicable) 350 A

Segment Energy (6 MJ max3) MJ

Segment Energy Discharge Rate (Ref FH Rules Appendix A) C

Table 20 - SMD Data

*Note the internal SMD should not be removed while current is flowing. The hot plugging current rating is 75A.

12.5 Lithium-Ion Pouch Cells The vehicle accumulator uses individual pouch cells. Yes No Note that designing an accumulator system utilizing pouch cells is a substantial engineering undertaking which may be avoided by using prismatic or cylindrical cells. If your team has designed your accumulator system using individual Lithium-Ion pouch cells, include drawings, photographs and calculations demonstrating compliance with all sections of rule

3 Note Segment energy = rated AH x nominal voltage. The 80% derating is NOT applied for this calculation.


EV11. If your system has been issued a variance to EV11 by the Formula Hybrid rules committee, include the required documentation from the cell manufacturer along with a copy of the variance.

12.6 Cell temperature monitoring Describe how the temperature of the cells is monitored, where the temperature sensors are placed, how many cells are monitored, etc. Show a map of the physical layout. Provide schematics for team-built electronics. The CellMan is responsible for making temperature measurements of the cells. There is one CellMan on every cell. A request for temperature measurement will be issued by the PackMan through the isolated SPI interface to a specified SegMan. The SegMan will then issue a command over a connection to the CellMan. The interface between SegMan and CellMen is a proprietary two wire connection by Linear Technology in their LTC6804 (SegMan chip) and LT8584 (CellMan chip).

Number of Cells with Temperature Monitoring 28

Total Number of Cells 28

Percentage Monitored (𝑉𝑉𝑉𝑉𝑉𝑉𝑚𝑚𝑟𝑟𝑉𝑉𝑟𝑟𝐶𝐶𝑚𝑚 / 𝑟𝑟𝑉𝑉𝑟𝑟𝑟𝑟𝐶𝐶) 100%

Percentage Required by FH Rules: Table 11 30%

If each sensor monitors multiple cells, state how many: N/A

Table 21 - Cell Temperature Monitoring

12.7 Accumulator Isolation Relays (AIR)

Describe the number of AIRs used and their locations. Also complete the following table.

Manufacturer Gigavac

Model Number GX14CB

Contact arraignment: Single Pole Single Throw Normally Open

Continuous DC current rating: 350 A

Overload DC current rating: 1000 A for 85 sec

Maximum operation voltage (contactor): 800 VDC


Maximum operation voltage (coil): 32 VDC

Nominal coil voltage: 24 VDC

Normal Load switching: Make and break up to 600 A

Table 22 - AIR data

12.8 Accumulator wiring, cables, current calculations

Describe internal wiring with schematics if appropriate. Provide calculations for currents and voltages and show data regarding the cables and connectors used. Discuss maximum expected current, whether DC or AC, and duration Compare the maximum values to nominal currents Cells are connected with aluminum bus bar made in house. All bus bars have the cross sectional area and thus the same current carrying capacity.

Figure 18 - TS Bus Bar between Cells

Areacross_section = 0.2 in * 0.87 in = 0.174 in2 = 112 x 10-6 m2

Length = 2.75 in = 0.06985 m ρ = 2.80 x 10-8 ohm * m for aluminum

R = 1.75 x 10-5 ohms R/l = 0.251 ohms / km


This resistivity is similar to 2/0 AWG wire which is sufficient for carrying 300 A continuously.

12.9 Accumulator indicator

If accumulator container is removable, describe the voltage indicator, including indicating voltage range The high voltage indicator LED will be illuminated when the car side of the AIRs on the pack has voltage of at least 18 VDC. The high voltage indicator LED should be off when less than 18 VDC is present.

Figure 19 - High Voltage Indicator

12.10 Accumulator Container/Housing

Describe the design of the accumulator container. Include the housing material specifications and construction methods. Include data sheets for insulating materials. Include information documenting compliance with UL94-V0, FAR25 or equivalent. The accumulator container is framed in 80/20 aluminum extrusion with HDPE panel inserts forming the main container. If the housing is made of conductive material, include information on how the poles of the accumulators are insulated and/or separated from the housing, and describe where and how the container is grounded to the chassis. Include additional photographs if required, to illustrate compliance with rule EV2.4. Show how the cells are mounted, use CAD-Renderings, sketches or photographs showing compliance with FH Rule EV2.4.7.


The accumulator container is framed by 80/20 aluminum extrusion. The bottom surface of the container is a ¼” Garolite sheet inserted into the T-slot of the 80/20 aluminum extrusion. All side panels of the container are ¼” HDPE sheets. The top of the enclosure contains two region with ¼” aluminum sheets and a hinged HDPE door. The aluminum sheet are used for ensuring that there is proper chassis grounding with connectors and metallic fasteners used on the connector. The cells are mechanically secured by being inserted into a HDPE slotted base. Each cell slides vertically into place. When the lid is secured in place by toggle clamps, the lid will push on the Garolite lid that provides 100% enclosure of the cells. Inside this Garolite box, the two segments of 7 cells are contained. They are separated by Garolite divider. The narrow volume that extends along the length of the containers is the GLV region. All GLV components and wiring is contained in this region except for the AIR and isolated SPI cabling. There are two GLV cables that extend to control the AIRs. Additionally, there are two cables that extend in the cell container that are isolated by transformers on the TS and GLV side of the cable.

HDPE Lid

Garolite Lid

HDPE Cell Base

AIRs

GLV region

TSV region


Figure 20 - Accumulator Container Details

12.11 HV Disconnect (HVD)

Describe your design for the HVD and how it is operated, wiring, and location. Describe how your design meets all requirements for EV2.9.

HDPE Lid

Force from the HDPE lid is transferred through the Garolite box to the top of the cells.

HDPE Cell Base

Segment A Segment B

Segment Divider

GLV region

TSV region


The HVD is an Amphenol PowerLok connector, PL28W-301-70 and PL00W-301-10D10. It is operated by manually by pressing the unlocking tab and unplugging the connector from its receptacle. It can maintain its disconnected state as long as it is not connected to the receptacle. This can be secured easily by zip tie to the frame. The HVD is fitted by simply pressing the cable into place. The HVD can be removed within 10 seconds of ready to race conditions without the assistance of tools. There are HVDs located on both ends of the accumulators as well as in between the two accumulator packs. Removing as HVD will break the series connection required for current to flow through the accumulators. Thus if disconnected, it will de-energize the TSAL and TSMPs.

s

Figure 21 - HVD Accumulator Pack Locations

HVDs

2019 Formula Hybrid ESF-2 (Rev 1) 42 Pre-charge / Discharge

Pre-charge / Discharge Person primarily responsible for this section:

Name: Hayden Dodge


13.1 Pre-Charge circuitry Describe your design for the pre-charge circuitry. Describe wiring, connectors and cables used.

• Include a schematic of the pre-charge circuit • Include a plot of calculated TS Voltage vs. time • Include a plot of calculated Current vs. time • Include a plot of resistor power vs time.

The Pre-charge circuit consists of a pre-charge relay, a pre-charge resistance, and a high voltage comparator circuit on the TSI board. The pre-charge relay used is a Gigavac GX14CB, the same relay that is utilized in the battery packs for AIRs. In order to be compliant with EV6.1.7 and EV2.10.7 concurrently, the resistive load is split into two pre-charge resistors connected in series. Since a smaller gauge wire is used, the wire must be protected by current limiting resistors on both side in the event one end were to come loose. This achieves protection without the use of fusing which is prohibited in the pre-charge circuit. When the high voltage comparator measures the voltage on the motor controller side of the pre-charge circuit to be 95% of the voltage on the AIRs side, the pre-charge relay is closed creating a low impedance path for the TS path. This is above the 90% requirement set in EV2.10.1.

Figure 22 - Pre-charge Circuit (PDF)





Figure 23 - Pre-charge Circuit Voltage, Current, & Power Analysis

Assumed 100 VDC TS Voltage for analysis above Power is dissapated by two resistors in series.

Provide the following information:

Resistor Type: KAL25FB25R0 Wirewound chassis mount

Resistance: 25 Ω

Continuous power rating: 25 W

Overload power rating: 125 W for 5 sec

Voltage rating: ? VDC

Table 23 - Data for the pre-charge resistor

Relay MFR & Type: Gigavac GX14CB

Contact arrangement: (e.g. SPDT) SPST-NO

Continuous DC contact current: 350 A


Contact voltage rating: 800 Vdc

Table 24 - Data of the pre-charge relay

13.2 Discharge circuitry Describe your concept for the discharge circuitry. Describe wiring, connectors and cables used.

• Include a schematic of the discharge circuit • Include a plot of calculated TS Voltage vs. time • Include a plot of calculated “Discharge current” vs. time • Include a plot of resistor power vs time.

The Discharge circuit consists of a discharge relay, two discharge resistors, a current sensor, and two fuses. The components are connected by wires, aluminum bus bars with ring terminals, screws, and nuts. The 2/0 TSV cables are used to supply high voltage to this circuit through the bus bar ring terminals. The relay control connections and resistors are connected with 16-22 AWG gauge wires. The bus bar and ring terminals are connected with M5 sized bolts.

Figure 24 - Discharge Circuit (PDF)





Figure 25 - Discharge Circuit Voltage, Current, & Power Analysis

Assumed 100 VDC TS Voltage for analysis above Power is dissapated by two resistors in series.

Provide the following information:

Resistor Type: HS50 50R F Wirewound

Resistance: 50 Ω

Continuous power rating: 50 W

Overload power rating: 663 W for 5 sec (See Note1)

Voltage rating: 1250 V

Maximum expected current: 1 A

Average current: ~ 0.2 A

(during first 5 seconds from full TS voltage)

Table 25 - Discharge Resistor data (two resistor are in parallel in the discharge circuit)


Note 1: Calculated maximum energy impulse for 150° C temperature rise. This is a safe impulse assumption because the abient temperature is aproxiamately 25° C and the resistors will become damaged when it reaches 200° C thus allowing a 25° C factor of safety. Further we can assume adiabatic conditions for the transient analysis.

Figure 26 - Discharge Resistor Drawing

D = 14.2 mm E = 49.1 mm Areacross_section = Semicircle + Rectangle = π(D/2)^2/2 + D(D/2) = 180 mm2

Volume = Areacross_section* E = 180 mm2 * 49.1 mm = 8840 mm3 = 8.84 cm3 The volumetric heat capacity of most solids ranges from 2 to 4 J*cm-3*K-1. The resistor is likely made of aluminum and copper along with some insulator. Assume a uniform specific heat of 2.5 J*cm-3*K-1 to be conservative. (Cp,v = 2.5 J*cm-3*K-1) Heat Capacity of Resistor = Cp,v * Volume = 22.1 J*K-1 Energy for temperature change = Heat Capacity of Resistor * Temperature Change

= 22.1 J*K-1 * 150 K = 3,315 J For a temperature increase of 150° C, the resistor must gain 3,315 J adiabatically. So an estimate of overload power for a single pre-charge resistor is

3,315 W for 1 sec, 1,658 W for 2 sec,


1,105 W for 3 sec, or 663.0 W for 5 sec.

2019 Formula Hybrid ESF-2 (Rev 1) 50 Torque Control

Torque Control Person primarily responsible for this section:

Name: Hayden Dodge


14.1 Accelerator Actuator / Throttle Position Sensor Describe the accelerator actuator and throttle position sensor(s) used, describe additional circuitry used to check or condition the signal going to the motor controller. Describe wiring, cables and connectors used. Provide schematics and a description of the method of operation of any team-built signal conditioning electronics. Explain how your design meets all of the requirements of FH Rules IC1.6 and EV3.5.

Actuator / Encoder manufacturer The Sensor Connection

Model Number LPPS-050 50mm stroke

Encoder type (e.g.Potentiometer): Potentiometer

Output: 0 to 100% of excitation voltage

Is motor controller accelerator signal isolated from TSV?

Yes / No

If no, how will you satisfy rule EV3.5? Yes but additional isolation is achieved on the TSI board

Table 26 - Throttle Position encoder data


Figure 27 - TSI Throttle Isolation Circuit

(PDF)

14.2 Accelerator / throttle position encoder error check Describe how the system reacts if an error (e.g. short circuit or open circuit or equivalent) is detected. Describe circuitry used to check or condition the signal going to the motor controller. Describe how failures (e.g. Implausibility, short circuit, open circuit etc.) are detected and how the system reacts if an error is detected. State how you comply with EV3.5.4. The throttle position sensor consists of two 5k ohm potentiometers. They are mechanically linked in parallel and will actuate over the same range. The pedal is mechanically limited to 90% of the potentiometer travel range for open/short detection. The first pot (APPS1) is biased from 5-10 volts and the second pot (APPS2) is biased from 0-5 volts. In order to detect open/short circuit conditions APPS2 is passed through a window comparator with a valid range of 0.25-4.75, similarly, APPS1 has the 5 volt bias removed and is passed through a window comparator with the same range. In order to detect throttle plausibility, the biased APPS1 and APPS2 signals are passed through a differential amplifier. The output of the diff-amp is then passed through a window comparator with valid range of 4.5-5.5 volts. This range tolerates up to a 10% difference between APPS1 and APPS2. All of the comparator outputs are tied to a NAND gate. If all comparators have logic high outputs the NAND gate sets the throttle plausibility signal low, allowing the throttle signal from APPS2 to pass through an isolator and then be sent to the motor controller.




Figure 28 - Throttle Plausibility Circuit (PDF)



2019 Formula Hybrid ESF-2 (Rev 1) 53 GLV

GLV Person primarily responsible for this section:

Name: Max McFarlane


15.1 GLV System Data Provide a brief description of the GLV system and complete the following table The GLV system is comprised of a single 24V LiFePO4 battery, the safety loop, and VSCADA. The battery provides 24 VDC to all low voltage electrical systems. The safety loop assures all systems are functioning properly before opening the AIRs and allowing high voltage from the accumulators. The safety loop is also the shutdown circuit for the vehicle. The display of VSCADA is mounted externally on the GLV enclosure. This display screen allows for touch screen input for display options of collected data.

GLV System Voltage (Same as Table 1) 24 V

GLV Main Fuse Rating 15 A

Is a Li-Ion GLV battery used? Yes / No

If Yes, is a firewall provided per T4.5.1? Yes / No

Is a dc-dc converter used from TSV? Yes / No

Is the GLV system grounded to chassis? Yes / No

Does the design comply with all requirements of EV4? Yes / No

Table 27 - GLV System Data

2019 Formula Hybrid ESF-2 (Rev 1) 54 Charger

Charger Person primarily responsible for this section:

Name: Hayden Dodge


16.1 Charging Describe how the accumulator will be charged. How will the charger be connected? How is the accumulator to be supervised during charging? Include a diagram showing how the charging circuit is fused. The charging relay is on the Segment Manager Board (SegMan). The relay is controller by the Pack Manager Board (PackMan) through an isolated-SPI connection to SegMan. The SegMan detected when a charger is inserted into the Anderson PowerPole connector by detecting a shorted jumper in the charger. This allows the PackMan to make a decision to close the charge relay and begin charging. While charging, the PackMan will monitor cell voltages and temperatures and will open the charge relay if an overvoltage or over temperature occurs. Additionally, the PackMan will determine if any cell in segment has great state of charge (SoC) than any other cell. In this case, the PackMan coordinate active discharging of the cell with greater SoC and will re-distribute the charge across the whole segment. The charge relay can be opened to allows for SoC balancing to occur for greater cell capacity. When charging is complete, the charge relay will be opened.


Figure 29 - Charging Circuit with fusing – SegMan Schematic (PDF)

Note: Our charging circuit does not currently have any fusing. We are working to put in appropriate fusing on both sides of the charge port. Complete the table

Charger Manufacturer MEAN WELL

Model Number HLG-480H-30A

Maximum charging power: 0.480 kW

Mains Isolation Yes / No

UL Certification If “no”, fill in the line below.

Yes / No

https://sites.lafayette.edu/motorsports/files/2019/03/SegMan_sch-2.pdf

https://sites.lafayette.edu/motorsports/files/2019/03/SegMan_sch-2.pdf


Do you have a waiver from the FH rules committee? If “yes”, attach printout of the waiver.

Yes / No

Maximum charging voltage: 30 V

Maximum charging current: 16 A

Interface with accumulator (e.g. CAN, relay etc.) relay

Input voltage: 90-305 VAC

(single phase)

Input current: 5 A

Table 28 - Charger data

2019 Formula Hybrid ESF-2 (Rev 1) 57 Appendices

Appendices Include only highly-relevant data. A link to a web document in the ESF text is often more convenient for the reviewer. The specification section of the accumulator data sheet, and sections used for determining accumulator capacity (FH Rules Appendix A) should be included here.

2019 Formula Hybrid Electrical System Form 2 (ESF-2

Documents