Due to the fact that the sampling period of the control system is exactly the minimum width of the PWM pulses, the value of the sampling period determines in a significant manner the behaviour of the drive.
For the asynchronous motor of 2,2 kW rated power, the command with sampling period 100 ms, for hF = 0,05 Wb and ht = 1 Nm, determines the point of the stator flux to have the trajectory plotted in figure 6.
We notice the movement of this point following the directions of the stator voltage.
For the same values of the hysterezis of the two controllers, but with the sampling period of 500 ms, the point of the stator flux phasor describes the trajectory plotted in figure 7.
We notice that, due to the small commutation frequency, the preset hysterezis on the modulus of the stator flux can not be achieved anymore.
