
7-16 Power Electronics and Motor Drives
As mentioned earlier, operation in all four quadrants of the torque versus speed plane is a requirement
for many applications. Given the symmetric shape of the inductance prole with respect to the aligned
rotor position, one can expect that for a given conduction band at a constant speed, current waveforms
during motoring and generating should be a mirror image of each other. However, one should note that
the back-EMF during generation acts as a voltage source resulting in an increase of phase current even
aer a phase is shut down. is may cause some complications in terms of stability at high spee