Comparative Study of a Novel Symmetrical and Asymmetrical Interior Permanent Magnet Synchronous Machine for EVs Application

Based on symmetry the Interior Permanent Magnet (PM) synchronous machines are divided into symmetrical and asymmetrical designs. The asymmetrical design is better due to the asymmetrical flux barriers in the rotor, which control the leakage flux and convert it into useful flux. This paper compares two novel designs, symmetrical (IPM-I) and asymmetrical (AIPM-I). Both have the same stator and rotor parameters, the same volume of PMs, and three-phase distributed windings. The IPM-I and AIPM-I have a spoke and delta shape PMs configuration but only changes in the flux barriers. The flux barriers in the IPM-I are symmetrical while in AIPM-I are asymmetrical due to control of the leakage flux in the symmetrical design. compared the dynamic performances of the load and no-load conditions and concluded that the asymmetrical design torque (6.78 Nm) is greater than the symmetrical one (6.41 Nm). Also, comparing the efficiency and loss maps of both the designs, and concluded that the asymmetric design has greater efficiency (95.41%) than the symmetric design (94%). Copper and iron-loss maps are also compared which are almost the same.