According to the Hall sensor signals uC[m=3]
, the inactive (open) leg is choossen
as well as the two legs that apply the DC voltage to two terminals of the machine,
and therefore let a current flow through the corresponding phases of the machine
to obtain a current space phasor perpendicular to the rotor's magnetic field.
Of course due to the block commutation the angle between rotor position and current space phasor
varies in the range [±90° - 30°, ±90° + 30°]
.
Setting the input pwm = true
chooses the position of the current space phasor as +90°
, whereas
setting the input pwm = false
results in a position of the current space phasor as -90°
w.r.t. the rotor position.
Applying a pwm signal (as for a brushed DC machine) to the input pwm
offers the possibility to set the mean voltage applied to the phases choosen according to the Hall signals.