Wide Frequency Band Equivalent Circuit of Interior Permanent Magnet Motor for Static State and Frequency Response Evaluation Based on the Equivalent Circuit

Aiming to evaluate and compare the performance of Interior Permanent Magnet (IPM) motors in a wide frequency range extending from low to switching frequency bands, wide frequency band equivalent circuits were constructed for stator assemblies and IPM motors to evaluate their static state. These equivalent circuits were introduced by combining the electrical equivalent circuit derived from the magnetic circuit with that of the armature winding and magnetic cores. The impedance and the input power of the armature winding terminals were calculated based on the derived equivalent circuit, and the measurements were compared. The results clarified that the leakage inductance caused by the magnetomotive force due to iron loss should be considered, which is not considered in the excitation circuit of conventional equivalent circuits of transformers and induction machines, along with the impedance associated with the capacitance between the armature winding and stator core. In addition, the equivalent circuit of the rotor portion should consider the capacitance between the magnet and rotor core.