Does device power supply/power from aircraft need to rely on running PSDK?

There is no need to run PSDK. As long as the hardware is connected and the specified pins meet our agreed level status, power can be drawn from the aircraft.

For Flycart 30, the default output voltage of the air suspension interface is about 1.2V. You need to call the high power output interface in PSDK to obtain 60V voltage normally. (The hardware pins and the pins in the code do not need to be changed. Just pay attention to the call of DjiPowerManagement_ApplyHighPowerSync interface.)

For reference:

https://developer.dji.com/doc/payload-sdk-tutorial/cn/quick-start/drone-port.html

https://developer.dji.com/doc/payload-sdk-tutorial/cn/function-set/basic-function/power-management.html