Electromagnetic Performance Analysis and Verification of a New Flux-Intensifying Permanent Magnet Brushless Motor With Two-Layer Segmented Permanent Magnets

Permanent magnet brushless (PMBL) motors have been widely applied in electric vehicles, since they inherently offer high efficiency, high power density, and free maintenance. However, because of the existing problem of uncontrollable flux, their constant-power speed range is relatively narrow. In order to gain a wide speed range, by employing the new concept of the flux-intensifying effect, a new flux-intensifying PMBL (FI-PMBL) motor is proposed in this paper. The proposed motor is innovatively designed, where the topology of two-layer segmented PMs and non-uniform air gap are adopted to make the corresponding d-axis inductance L-d become greater than the q-axis inductance L-q, which is far different from the conventional interior PM motor. By using the finite-element methods, the electromagnetic performances of the proposed motor are evaluated in detail. Simulation results show that the proposed motor possesses preferable flux-weakening capability and wide speed range. In addition, the experimental results of the FI-PMBL prototype are given to verify the performances of the motor.