Dear Community
I have developed a BLDC motor drive with a senorles BACKEMF control using a DRV10983 IC.
It uses sensor less control no halls used. If I look at the motors hall effects that are not used on the DRV10983 Chip My issue is that the speed is drifting hunting from 199.9Hz 200Hz 200.1Hz .
There are is 4 hall pulses per revolution so RPM = 200 x60 /4 = 3000 RPM
ON a blown up zoomed in graph with low pass filters the speed is gradually hunting between 2998.5RPM and 3000RPM and 3001.5RPM as speed drift.
I know this is a tiny tiny speed variance of only +/-0.05% of target speed of 3000 rpm but
The instrument the motor turns has an optical measurement system and the rpm drift is hunting the readings slightly
To see what I mean please click this link its a post I made on the DRV10983 Forum
http://e2e.ti.com/support/motor-drivers/f/38/t/860404
my question to BLDC experts / Users Can a sensored Hall effect with STEVAL SPIN3201 Kit improve the speed stability to say +/- 0.25 RPM or better.
Can a good PI Speed control with hall effects decrease the RPM drift to a smaller amount.
Or is +/- 1.5RPM in 3000 RPM the best speed stability achievable in sensored or sensorless
control.
Sorry this post was previously posed in the wrong section its more viable in this Motor Driver ICS and boards section.
Thanks for reading any advice would br really appriciated.
