Dear Sir,
We use a DRV10983 IC in our motor driver unit for driving a maxon motor. The assembled unit is finally for a drone application. The units work fine in ground but in cases with Drone Rotor Thrust above 10%, multiple units fail to start at random times (Drone and the motor units are fed from the same battery supplies through DC-DC converters). We had implemented a data logging that reads from the DRV10983 registers to see what is the driver status when the failure occurs. The following are the major observations:
1. The external PWM command from a micro-controller is received properly at all times through the I2C communication during the issue.
2. The internal speed command registers (0 - 511) also follow the required speed command during the issue
3. The supply Vcc to DRV10983 IC also is present throughout the duration of the issue
4. No faults - neither status nor lock - is recorded during the issue.
5. For some reason the motor current draw is near zero (~0.01 A)
6. Also, the speed registers which record the actual speed shows sub 500 RPM values, with no actual real world rotation observed
7. Once the Drone Rotor Thrust is brought down below (30% - 10%), the motors resume operation automatically
Kindly shed some light as in how else can the Driver IC not draw current or drive the motor in a non-fault condition
1. The figure titled 'Normal Turn-ON Operation Current' shows the current values recorded from driver current registers when the motors start operation normally
2. The figure titled 'Failure to Start Current' show the current behavior recorded from driver current registers when the motors fail to start under drone rotor thrust 45% till horizontal axis value of 397 and;
beyond that is when drone thrust is brought down to 30% and motors resume operation
Thank You,
Jain James