Control of motor by MOSFET (by hassan)
Is it possible to help from the experts? I want to control the motor of a forward and backward direction at a speed of 10 hz via two keys.
Please help. Six control outputs and the coil for clarification.
(no subject) (by Ziggy)
The schematic is OK.
The problem is to implement an algorithm to get the motor to run with reasonable torque.
I assume the motor is a brushless, sensorless DC motor.
Such motors typically require a predefined starting point along with back emf sensing.
At any point in time only two of the three windings are energised in a predefined sequence.
Initially the motor is brought into a known position by energising only two predetermined windings.
This is followed by the next pair of windings being energised so that the rotor starts to move ( there are six valid combinations of energising windings for a full 360 degree turn of the shaft.)
Back emf builds up with shaft speed and depending on how well the BEMF sensing circuitry works the motor may be switched from a slow ... very slow acceleration regime untill BEMF sensing works ok to full synchronised switching , synchronised to motor rotor speed.
Starting and direction changes are a problem without hall sensors.
as MGP pointed out.. a hard thing to tune and get to run well .