I am currently working with torque control of a BLDC motor. Hall effect sensors are used to determine the position of rotor(permanent magnet). The stator is energized by 3-phase current. Depending upon the signals recieved from the hall effeect sensors,particular stator coils are energized (commutation ). I am not clear why the position of rotor needs to be determined to keep the motor running. Need some help.
On Wed, 10 Jan 2007 22:21:24 -0800, Vaithy Has Frothed:
-- Pierre Salinger Memorial Hook, Line & Sinker, June 2004 COOSN-266-06-25794
I'm no expert on brushless motors, but the general idea is to energise each of the three coils in the correct timing and sequence to push/pull the rotor in the required direction. If your timing is out, the motor will not run reliably at the required speed and in fact may even be pulled backwards. The hall sensors allow your controlling software to know the exact position of the rotor so that you know when to energise the next coil in the sequence. In other words, the rate at which you energise the coils determines the speed of the rotor, but without the hall effect sensor's position feedback there'd be no way of knowing where the rotor is and which coil to energise next. Hope this helps a little.
... TDF
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