Hi Everyone,
I have a question I hope someone can shed light on for me. I have a pretty good high-level understanding of motor control. One thing I've wondered for a long time, though, is why do they typically use sigma-delta converters for the current sense portion. This would be from phase motors such as BLDC and AC Induction.
Consider Avago Tech's solution from their website: http://www.avagotech.com/pages/en/industrial/motor_control/ . The "Phase Current Sense" block suggest several amplifiers build from sigma-deltas and then a stand alone sigma-delta block without any digital filter stage. What is the advantage of using that over, for instance, just a straight SAR converter. The SAR converter would give the true value without another filter block.
I've seen this basic block diagram from several suppliers, but I've never figured out the driving benefit.
Does anyone know why sigma-deltas are preferred for motor drive current sense?
I have a question I hope someone can shed light on for me. I have a pretty good high-level understanding of motor control. One thing I've wondered for a long time, though, is why do they typically use sigma-delta converters for the current sense portion. This would be from phase motors such as BLDC and AC Induction.
Consider Avago Tech's solution from their website: http://www.avagotech.com/pages/en/industrial/motor_control/ . The "Phase Current Sense" block suggest several amplifiers build from sigma-deltas and then a stand alone sigma-delta block without any digital filter stage. What is the advantage of using that over, for instance, just a straight SAR converter. The SAR converter would give the true value without another filter block.
I've seen this basic block diagram from several suppliers, but I've never figured out the driving benefit.
Does anyone know why sigma-deltas are preferred for motor drive current sense?