Rev 3(5.2)

Owned by Yuchen Lin
Last updated: Jul 25, 2024
1 min read

Context:

Our team currently find a strong need for a PDB.

  • Simplify the wiring by a significant amount.

However, when testing the older revision of the PDB, we observed some issues with the previous iteration.

RCA:
The previous tests have indicated the root of the spark is from the current sensing side, not the actual power line. Wolfgang suggests it might caused by shorting the board. But need to redesign it due to upgraded spec.

Goal:

  • Further, simplify the PDB

  • respec the whole system based on the current spec

    • Unprotected:

      • 48V 3A max

    • Protected

      • Drivetrain (Step down to 24V)

        • 48V 20A

      • Arm (Step down to 24V)

        • A2 + A3

          • 48V 10A

        • rest 48V 20A

      • Science (TBD)

        • 48V 10A

      • Sensor (TBD)

        • 48V 3A

The team does not have strong confidence that the customized Buck will work 100% without a doubt based on the current testing. Therefore, the current plan is to change the connector of the Buck Converter and make it interchangeable with the OFF THE SHELF solution.

Request for change:

  • Reduce the number of voltage-sensing and current-sensing

    • Voltage sensing is only implemented with High-value electronics

    • Current sensing is only with high load application

    • assume the buck does not overvoltage, or Undervoltage and lead to device failure

  • Include plug-in Fuse (reduce the need for current sensing)

  • Include rail fault detection

    • open HIGH LOAD Or HIGH-VALUE rail if short is detected

  • Include 12V rail in the current system

  • Include ESTOP and 48V RELAY in the system

  • INPUT FUSE MUST BE REPLACEABLE

  • Replace the screw terminal with one can take the higher gauge

  • User define jumper

    • Power via USB or power supply when programming

    • Enable arm system or science system

    • Enable current sensing for the rail(if there is a fault in current sensing, can disable the circuit and continue using PDB)

  • Reduce the impact of the inrush current on the ESTOP

Summary:

 

 

 

PDB_ARCH_REV5_2.drawio(2).png

 

The current research has indicated that all our motors are best suited for 24V power, not 48V.

 

The focus of the new revision of PDB is to update the power side, not the controller side. Maybe it could be beneficial to support UART + CAN just as a backup. The POE Method for the router needs to be evaluated since an ethernet splitter might be beneficial.