Ok, here we go again with my lack of knowledge on digital control, so pardon me if it looks I'm just waving hands in the blind (I'm not blind but I'm italian and waving hands is pretty much a genetic feature).
I have a Controller block which provides the torque (T) value to be applied to a BLDC motor. Now T needs to be converted into current (I) for each of the three phases of the motor according to the actual angular position, provided by an absolute encoder.
The chain of the Controller+Converter ia updating a new value at f KHz. Now, within my period 1/f I need to *regulate* the current with an error max of x% FSR and we thought about having a delta-sigma modulation driving an half H-bridge (class D amplifier) with some lpf before goint on the motor coil.
Now, how can I estimate the frequency for my regulation loop? and the level of the quanitzer? Which are the parameters I need to play with? Would I need to simulate the motor as well or can I leave with an open loop analysis?
Any pointer is appreciated (even to books if you deem not worth discussibg before I get a proper education on the subject!)