Hello,
We have developed a BLDC driver around the DRV8306 IC to drive a BLDC motor. The datasheet of the motor is attached and the schematic of our PCB is attached.
The issue we are experiencing is that during no load testing, the motor current ramps up exponentally and trips our current protection which then disables the motor. According to the motor datasheet, the no-load current should be around 6A, but our measurements show that the current reaches up to 80A and then trips the protection. The measurement of the total current flowing into the driver is measured on the shunt R30 and is attached below.
We think that the time interval between the current transition from its minimum value to its maximum value is related to the transition of one hall segment. Each time the rotor is in a new hall segment the current transition repeats.
We think that the current measurement resembles the saturation of the magnetic core, and hence the rapid increase in current, however we cannot find an explanation as to why this is happening at no-load.
We are looking for any kind of advice that could help us overcome this issue.
Thanks,
Samo Smodiš
