Hello,
I have been trying to utilize the DRV10983EVM to drive a BLDC motor, and have had very little success. I followed the tuning guide provided by TI (SLOU395D) to obtain the motor parameters, which are as follows:
Rm = 3.1 ohms (phase-phase resistance = 6.2 ohms)
BEMF Constant = 207mV/Hz.
When I input these numbers into the GUI, I am able to get the motor to control with the "closed loop disable" box checked, but once I uncheck that box, the motor spins up to an insanely high speed, regardless of the position of the potentiometer or the speed command sent via I2C.
I then started playing with a few of the settings to see if I could get it to work, and discovered that changing the BEMF constant to 161mV/Hz allowed me to control the motor speed, both with the potentiometer and with I2C commands. During alignment and the open-loop startup portion, the eval board draws ~100mA. The only problem at this point is that once it enters closed loop, the drive current to the eval board drops to under 10mA. Once I put a load on the motor shaft, the motor stalls when the current gets to ~30-50mA.
I am looking at utilizing this motor driver to replace some existing circuitry on one of our products, and the existing circuit draws closer to 80-100mA during normal operation. When I load the motor on this circuit, the current draw increases to ~500mA before the motor stalls, and the motor has significantly more torque.
Additionally, when I set the number of poles on the display tab of the GUI to 4 (the number of poles on the motor I am running, the speed displayed is many times the actual rotation speed of the motor.
Any suggestions?
