Time-Stepping Simulation of Synchronous Reluctance Motors Using a Nonlinear Reluctance Network Method

We present a nonlinear reluctance network approach for the computation of the electromotive force (EMF) waveforms of synchronous reluctance motors (SynRM) with a massive rotor or a flux barrier rotor. We model all ferromagnetic parts of the machine by nonlinear reluctances in order to take the saturation into account. The model of the motor consists of three reluctance networks: of the stator, of the rotor, and of the air gap. The originality of the work lies in the automatic computation of the topology and of the reluctance values of the reluctance network. The computation models the air gap for any relative position of the rotor and the stator; thus, the movement of the rotor can be taken into account. For any saturation level, a comparison with time-stepping finite-element results shows good agreement for the EMF fundamental, the mean torque, and the EMF and torque harmonics of order lower than the slotting ones. For a normal saturation level, the reluctance network models also accurately compute the slotting harmonics.