Experimental assessment of a permanent-magnet synchronous motor representation including Q-axis saturation

The authors have concentrated their attention upon inclusion of the saturation of L_q as a function of I_q, in the belief that this represents the major influence of saturation upon performance. Thus, computations for a current-fed machine using measured values of parameters showed that q-axis saturation produced 30% reduction in torque at rated current with optimum β. On the other hand, it was clearly shown that q-axis saturation had no effect on maximum speed as β approaches 180° with constant current, since q-axis flux falls towards zero in this region. The authors present the results of an experimental investigation and compare accurately measured performance with computed predictions including q-axis saturation