An analytical calculation model for inductances of multi-unit PMSM with concentrated windings

To be suited for low speed high power application, a multi-unit topology permanent magnet synchronous motor (PMSM) was proposed to be used in superpower electric propulsion since it offers comparatively high output power, good fault-tolerant ability, and requires comparatively low single driver output power. The traditional three-phase control strategy can be simplified and used in this kind of motor. The inductance components of the multi-unit PMSM with concentrated coil fractional pitch double layer windings are different from the traditional three phase PMSM. The mutual inductances of the different phases are also not the same. This paper presents an analytical model for calculating the self inductance and mutual inductance components of multi-unit topology PMSM by first using winding function method to obtain the winding configuration and by setting up an armature reaction flux model to present the magnetic flux circuits of the motor, with the circuit theory. From the magnetic flux circuits, the self inductances and the mutual inductances of the multi-unit PMSM can be determined. A comparison of the analytical calculating results with FEM calculations show that the analytical calculation model is validated.