I am looking for a peer review for a design I am working on to switch the power (no-load) between a 16S battery (67.2V) and an ESC (Electronic Speed Controller).

I have come up with the following schematic, which switches the negative supply between the battery terminal and ESC (the positive is permanently connected) and includes a pre-charge circuit...







The design needs to be able to handle 300A DC, but the MOSFETs will only be turned on/off under no-load conditions.

The gate commands will be controlled by an STM32L031K6 MCU

For the PCB, I have designed a control board and a power board. The power board will be 8 layers and all layers will use 4oz copper (with vias).

Links to datasheets are below...

Gate drivers:
https://www.ti.com/lit/ds/symlink/ucc27511a.pdf

Main power MOSFETS (3 in parallel):
https://www.infineon.com/assets/row...49/infineon-iaut300n08s5n012-datasheet-en.pdf

Pre-charge MOSFET:
https://www.st.com/resource/en/datasheet/stp80nf10.pdf

Pre-charge resistor (10R 50W):
https://www.vishay.com/docs/50050/lto50.pdf

MCU:
https://www.st.com/en/microcontrollers-microprocessors/stm32l031k6.html

 

What is the purpose of the "PRECHARGE" inputs.

 

What is the purpose of the "PRECHARGE" inputs.

The ESC has bulk capacitors.
If you connect a Dc source to such large capacitance it draws huge current. The current is limited only by the resistance of the leads/connectors etc because the capacitor initially appears as a short circuit until it begins to charge. The pre charge circuit uses a series resistor to limit the current whilst the capacitors charge. It’s a technique commonly used with voltage source inverters such as EVs etc