Improved physics-based permanent magnet synchronous machine model obtained from field computation

The physics-based phase variable model of permanent magnet synchronous machines is developed for the simulation study of machine control. The parameters of the physics-based phase variable model, inductances and flux linkages are calculated from the solutions of nonlinear FE computation covering a complete AC cycle to consider the geometry details, the rotor position, the armature currents, and the magnetization nonlinearity. In the previously developed model, the impact of the armature currents on inductances is ignored considering the fact that field of PM machines is dominated by permanent magnets. In the improved model, presented in this paper, the variation of inductances with the armature currents is evaluated and added to meet the demand from those control applications which require highly accurate inductances. In this paper, three issues associated with the development of the improved model are presented. First is the method used to describe the inductances variation with the armature currents. L(thetas, i
_d
, i
_q
) is used instead of L(thetas, i
_a
, i
_b
, i
_c
) ; the reasons are thoroughly explained. Second is the verification of the improved model, given by the comparison of the improved model with the FE model. Third is the comparison between the previous model and the improved model, clarifying the validity of each model from the application point of view.