Part Number:DRV10970
Hello,
I am interested in using the DRV10970 for speed control of a BLDC motor with hall effect sensors (Maxon part # 339267). I should note here that my eventual goal is to use the DRV10970 for position control, but first I intend to get the speed control loop working properly.
It is my understanding that the DRV10970 is an open loop device that simply maps the user-provided PWM input on pin 19 to the PWM outputs that are sent to the bridge. It also provides a tachometer output on the FG pin. So at a high level, the user has access to the control input (PWM input pin) and the system output (FG tachometer output pin), but it is the user's responsibility to close the loop (by using a control algorithm implemented on a microcontroller, for example) so that a target speed can be maintained under varying load conditions. Is all of my understanding here correct?
If I am understanding things correctly, I intend to use a PI or PID control law to close the speed loop. I have read that for speed control in BLDC motors it is advisable to have an inner current control loop surrounded by an outer speed control loop. Does the DRV10970 already provide this inner current control loop?
Can you provide any guidance on how to choose or tune the gains, sampling frequency, control update frequency, or any other pertinent parameters for the PI/PID speed controller?
Thanks in advance,
Dustin