
6-16 Power Electronics and Motor Drives
6.4.2 Computation under Load (SPM Motor)
Figure 6.19b shows the torque behavior versus rotor position of the SPM motor fed by q-axis current
only, while d-axis current is zero. Solid line refers to the Maxwell stress tensor computation. e circles
refer to the torque computation (6.18). e dashed line refers to the torque computation T
dq
, given by
(6.19). As expected, the behavior of T
dq
is smooth and close to the average torque.
6.4.3 Computation under Load (IPM Motor)
Similar results are found when an IPM motor is considered, as the IPM motor shown in Figure 6.1c. e
nominal current is xed to Î
n
=