Timeline:

• Requirements/Considerations - 4/7/2025

• Component Selection - 4/12/2025

• Initial Schematic - 4/16/2025

• Initial Layout - 4/23/2025

• Rev. A Ordered - 4/26/2025

• Firmware/Testing - idk

  • Active Precharge Testing w/ Bulk Cap next workday

  • All enable out, precharge ready inputs and sense inputs work

Description/Purpose

controls the vehicle…

Requirements

• Contactor Control

  • Array/Array Precharge → BPS Leader (in BB)

    • Separate board sends isolated, LV signals with comparison values (taps) for precharge resistor

  • Motor/Motor Precharge → VCU (in PDE)

    • Separate board sends isolated, LV signals with comparison values (taps) for precharge resistor

  • Fail open - AND gate between software/hardware comparison

    • Hardware - current op-amp comparison

    • Software - isolated ADC

    • Precharge threshold at 91%, lower threshold of 81% for hysteresis

• Integration with driver controls

  • Motor Control

    • Bridge between CarCAN & MotorCAN

    • Translate pedal state, gear state to drive commands

      • Pedal board on CarCAN, display on CarCAN

    • Moore FSM for motor control, regen, cruise

      • VCU will run this FSM

  • Regen

    • What to expect from driver?

      • Selection of regen amount

        • Based on empirical testing

        • As a function of current speed/conditions

      • Regen at setpoint (ideally 100%) when accelerator/brake aren’t pressed

      • At low speeds → will not regen, driver must brake mechanically

        • Send display message when regen is ineffective (need testing data)

      • When brake is pressed - keep regen enabled? will just be less effective since no line lock

    • What edge cases + how to handle?

      • BPS close to charging temp threshold → depends on current

      • SoC too high - 95% (dependent on conditions)

      • Messages BPS ↔︎ VCU

        • BPS sends regen_disable message, if VCU doesn’t ACK, BPS trip

          • VCU sends global regen_state message, if regen_state still on after BPS sends disable + delay, BPS trip

        • If we continue regen past a certain point (97%), BPS sends regen_disable → must wait for SoC <95% to regen again

  • Ignition Sequence

    • Off, Motor, Array states

    • Controls Leader waits until IGN switch is back to OFF state before broadcasting array or motor

      • Prevents starting in motor/array state

  • Debugging

    • For both BPS Leader and VCU - ESP32 connected to LSOM UART for necessary debug messages

    • Wifi for connection - test with actual enclosures for signal

• Electrical

  • LSOM - what peripherals/pins needed?

    • two CANs

    • UART

    • GPIO

      • Motor Drive

      • Motor Sense

      • Motor Precharge Drive

      • Motor Precharge Sense

      • Motor Precharge Ready

  • Additional ICs/circuits for anything?

    • On precharge boards (2x) isolated ADCs

• Mechanical

  • Packaging

    • small

    • more square is better - spread out around LSOM

    • black, gold plated, high def silks

    • no monkey bullshit

    • Power Distribution Enclosure (PDE)

    • sizing/space??

  • Connections

    • CarCAN In/Out, MotorCAN Out (terminating end)

    • Signals from precharge board

      • Two ADC outputs

      • Signal from hardware comparator output

      • 12V - use 12V tolerant ICs

      • one connector on board

    • Two contactor 4 pin

      • drive+, drive-, sense+, sense-

Application Note

how does this board integrate with others + any harnessing/bringup considerations. anyone should be able to read this and integrate this board into the electrical system

Context

Location of the board: Power Distribution Enclosure (vertically behind driver)

Connection List

Main

Schematics

every subsheet here

Circuit Components

all uniques (non-passives) in BOM + rationale for selection

Layout

PCB

3D Model

Firmware

Drivers

High-Level (Block Diagram)

Test Plan

1. Solder on connectors

2. Verify components are properly soldered

   1. blinky for every led one at a time

   2. enable disable contactor signal

   3. able to read adc

3. Test RPP

   1. input 0-32v to test full range of RPP

   2. 0-22v UV (theres no UV lockout, just testing it)

      1. yeah nothing happens

   3. 22-29 operating

   4. 29+ OV

4. Test ESP

   1. power over usb and test flashing

      1. ravi flashed a blinky

   2. test bluetooth (to be developed by dylan )

   3. send uart over esp and bluetooth (to be developed by dylan)

      1. uart broken out through logic analyzer connector

5. Test contactors

   1. open and close contactors, monitor sense signals

   2. simulate precharge thresholds

   3. simulate precharge thresholds using precharge board (perhaps also bomb board)

6. send receive CAN

   1. get dummy board to send controls can messages

   2. send car state and contactor messages

   3. FSM works for simulated can messages

   4. integrate FSM and precharge firmware

7. testbench testing

   1. connect to moco interface

   2. connect to moco as well

   3. motor spin

Meetings: