A simple analytical approach to model saturation in surface mounted permanent magnet synchronous motors

This paper presents a simple approach to account for saturation and its effects, based on varying effective air-gap length of an analytical model of surface-mounted permanent-magnet (PM) synchronous motor (SMPMSM). Firstly, the real structure of the machine is modeled with two concentric regions and the magnetic potential vectors are analytically calculated by solving the Maxwell´s equations. Then, the magnetic saturation of the iron parts is modeled by solving the Ampere law on a mean flux line. And finally, the saturated load operation is calculated by considering an equivalent no-load operation with a fictitious PM having a residual magnetic flux density that creates the same magnetomotive force (MMF) as the one created by both real PM and stator MMF. The analysis results are supported by experimental measurements and 2D FEA.