You are here

Will voltage offset on phase cause tracking to get wrong position?

2 posts / 0 new
Last post
TechAUmNu
Offline
Last seen: 1 day 20 hours ago
VESC Free
Joined: 2017-09-22 01:27
Posts: 575
Will voltage offset on phase cause tracking to get wrong position?

I am working on custom board based on VESC6 for 200A+, but it is not managing to track the motor position properly. 

The board has 10k pull down resistors on the mosfet gates which I think are causing a voltage offset on the phases.

This means the absolute voltage on each phase does not go below 0 when the motor is free running. So I tried turning the motor with a drill and the BEMF plot looks nice but the tracking oscillates between 45 and 65 degrees.

 

TechAUmNu
Offline
Last seen: 1 day 20 hours ago
VESC Free
Joined: 2017-09-22 01:27
Posts: 575

Removed the resistors and still have the same problem, it won't even track when the main supply is turned off and just turning motor by hand, even though the adc inputs are very good.