Hi,
we had several ODrive v3.6 56Vs that burned out in May, with the problem being DRV_FAULT error:
In [1]: dump_errors(odrv0)
system: no error
axis0
axis: Error(s):
AxisError.MOTOR_FAILED
motor: Error(s):
MotorError.DRV_FAULT
DRV fault: metadata not loaded
sensorless_estimator: no error
encoder: no error
controller: no error
axis1
axis: Error(s):
AxisError.MOTOR_FAILED
motor: Error(s):
MotorError.DRV_FAULT
DRV fault: none
sensorless_estimator: no error
encoder: no error
controller: no error
This is a persistent error, which can’t be cleared, does not disappear upon power cycling, but disappears if the DRV8301 chips are changed with new.
It might not be a ODrive at fault here. The motors attached to the ODrive are 300W hub motors for traction use (think e-scooter type of motors). However, our model is optimised for torque and has an in-built 4.3:1 reductor. Thus, even at modest speeds, the motors have significant bEMF, on the order of maybe 5-7 Vrms.
What we suspect is the following: the users might try to move the rover while it is completely unpowered. This turns the wheels, and creates bEMF voltage, and that one gets rectified and flows into the power supply rails of the ODrive through the body diodes of the MOSFETs. From there, it flows to the entire rover. We’ve seen some LEDs of the rover light up when we move the rover by hand with the power completely shut down. But we ourselves haven’t caused any breakage by doing that.
My question is: is it possible that this usage scenario can cause the destruction of the DRV chips?