Extended MTPA with cross coupling inductances for electrically excited synchronous motors

Electrically excited synchronous motors (EESM) are designed to have high power density for electric vehicle (EV) applications. Thus, severe nonlinearity is observed during high torque operation. The nonlinearity associated with core saturation is modeled by incorporating the cross coupling inductances which also behave nonlinearly. The analytic torque equation with the cross coupling inductances yielded good results that matched well with FEM data and experimental data. Further, an extended maximum torque per ampere (MTPA) method was proposed for the EESM model with cross coupling inductances.