Modeling and simulation of Switched Reluctance Motor for electric vehicle inside SOLIDWORKS using MotorWizard by EMWorks

A switched reluctance motor (SRM) is a rotating electric machine where both stator and rotor have salient poles (Figure 1). The stator winding comprises a set of coils, each of which is wound on one pole. FEM and CAD modeling of SRM are important because they save effort, time and money. The modeling and simulation start by a CAD design of an electrical machine. Later, the CAD geometry will be combined with numerical simulation using MotorWizard. In this article two-dimensional FEM is used to analyze the proposed motor. The 2D solution approximation is considered because of its capability to give fast and very close results compared to a real motor case. The static torque results obtained by MotorWizard will be compared to the measurement data published in ref [2].

Figure 1 - SRM geometry: a) 3D model b) 2D model

Figures 2a) and 2b) show the equipotential contours of the magnetic potential A which are equivalent to the magnetic flux lines (All current is assumed to flow perpendicular to the cross section) respectively in the case of the unaligned and the aligned position. The plots demonstrate a discontinuity in the flux lines because of the high magnetic reluctance in this position (large air gap) in the first case while they are following the ferromagnetic path from stator to rotor components without discontinuity (small air gap). Figure 3 shows the magnetic flux density in the case of the aligned position. The uniform air gap is modeled as a separate body (thin ring) which leads to deeper study of this critical zone.

Figure 2 - Magnetic potential equipotential contours: a) in the unaligned position b) in the aligned position

Figure 3 - Magnetic flux density in the aligned position

The plot of equipotential contours of A is attached to a cross section view of the motor 3D model in Figure 4. A comparison of the torque results is elaborated in Figure 5. The measurement data published in ref [1] shows a maximum value of 0.0349 Nm at 16 deg, While the torque computed by MotorWizard and the one given by ref [1] have peak values of 0.03 and 0.029 respectively. This small gap can be justified by the end effect which is neglected in 2D simulation.