Modules:

• charger_controller

  • uses mcp2515’s driver to send charging messages

    • methods:

      • charger_controller_init

      • charger_controller_activate

      • charger_controller_deactivate

  • charger_contoller_fault_monitor (merged into charger_controller)

    • registers can rx callbacks to find faults.

    • in case of a fault, broadcasts it to the rest of the car.

• charger_control_pilot_monitor

  • when PWM_READING_REQUEST is raised, it will use PWM to do a reading for max current.

  • raises a PWM_READING event with the max current reading.

• charger_connection_sense

  • sets up the interrupt for when the charger gets powered from AC.

  • raises a CHARGER_CONNECTED, CHARGER_DISCONNECTED, event when the interrupt triggers.

• permission_resolver

  • once the charger connects, it sends a permission request to centre console, here’s two cases:

    • centre console will grant permission

      • it starts the begin_charge_fsm

    • centre console won’t grant permission

      • charger does nothing, and waits for a disconnect and connect.

• begin_charge_fsm

  • it begins PWM reading by raising a PWM_READING_REQUEST

  • then it will wait for MAX_CURRENT_AVAILABLE

  • then it will set the state of the control pilot

  • then it activates charger_controller and charging begins.

• stop_charge_fsm

  • it will stop the charger_controller

  • it will set the control pilot pin

  • it will broadcast a CHARGER_DISCONNECTED CAN message. So centre console can allow for power state transitions.

• battery_voltage_monitor

  • repeatedly receives CAN_(battery_voltage)

  • if more than a threshold, begins the stop_charge_fsm

Incoming CAN Messages:

Outgoing CAN Messages:

Operation Mode:

1. The BMS sends operating information (Message 1) to charger at fixed interval of 1s. After receiving the message, the charger will work under the Voltage and Current in Message. If the Message is not received within 5s, it will enter into communication error state and stop charging.

CAN Communication

• Speed: 250Kbps

Addresses

Messages

Message 1:

This is the message we send to the charger.

Sender: 0xF4 → BMS

Receiver: 0xE5 → Charger Control System

Rest of the Message: 0x1806

• Priority: 6

• R: 0

• DP: 0 (fixed)

• PF: 6

Message 2

This is the status message charger sends to us.

Sender: 0xE5 CCS

Receiver: 0x50

CAN Communication

MCP2515 is responsible for sending and receiving CAN messages.

SAE J1772 Standard Notes

J1772 Plug Pinout

Control Pilot PWM

Circuit:

Proximity Pin (PP) or Proximity Detection

page 18 of standard:

Proximity Sense:

GPIO Address: PA7

Design Options:

• periodic ADC running always

• periodic ADC only activated when the charger is powered (PB1)

Charging Operation:

• car should be in park not neutral

  • we can either be in a undervoltage state, or neutral

• we’re also charging from solar

• need to have a threshold for opening the solar relays

• that threshold is not necessarily the overvoltage fault

  • cells are 95% charged

• whenever solar closed, battery has to be closed

• we should always make sure

• motor controllers must not be connected

• when car’s in parking, mci should disconnect

  • unless we’re not in an “undervoltage charge state” and we’re in “park” we should be able to charge

  • there needs to be continuous communication between BMS and the charger to taper the charging.

  • for MVP we keep it simple “two states”

• once charging done:

  • tell evse by setting the switch

  • tell charger to stop

  • open the relay

• shouldn’t go to neutral or drive again, unless we pull out the charger

After charging:

• bms needs to send a taper message

• bms needs to send a fully charged message

• talk to liam

Richard’s Notes

Notes on Charger CAN Comm:

Receiving Data:

·      Every second from BMS with CAN ID 1806E5F4

·      8 bytes of Voltage and Current requested

·      If no valid CAN message, charger stops charging until valid CAN message received

Sending Data:

·      Sends CAN message every second with Voltage, Current, and status information

·      Source Address - BMS – 2244(0xF4)

Stats & Errors:

·      Sends 2 messages, one to BMS and one to CCS

·      Output Voltage and Current (2 Bytes each)

·      Ex: if Byte = 1234 corresponds to 123.4V

·      Status Flags (Byte 5) 

·      Each status takes a bit (uses 5/8 bits)

Pre-Charging Safety Requirements:

·      All Status Flags are 0

·      Received valid CAN message from BMS (or CCS) 5 seconds or earlier

Controlled Relays & Hardware