Interior Permanent Magnet Synchronous Machines (IPMSM) attracts researcher’s attentions, due to their high efficiency, high torque and power density. Burring permanent magnet inside the rotor core increases mechanical robustness of the rotor construction at high speeds, compared to the surface permanent magnet synchronous machines (SPMSM). Therefore, IPMSM is suitable candidate for high-speed applications. One of the key desirable properties of IPMSM machines, which is essential in many applications such as electric vehicles, is its good flux-weakening capability. This property is related to the machines ability to deliver constant power over a wide range of speeds, without over sizing the converter or the machine. The aim of this thesis is to design an IPEM motor with higher speed operating capability and better flux-weakening capability. The thesis consists of two parts of rotor shape and stator winding designs. In the field of rotor shape design, some authors proposed segmented magnet for IPMSM. In these motors, the iron bridges between PM segments increases d-axis inductance (Ld), which in turn increases the flux-weakening capability of the machine. However, each iron bridge shortens its adjacent PM segments’ flux, which decreases the total magnet's flux (?m) in air-gap. Decreasing ?m results in decreasing the electromagnetic torque. This research presents appropriate positions and dimensions of these magnet-segmentations and iron-bridges to achieve a high d-axis inductance while losing minimum permanent magnet fluxes. In the field of stator winding design, many authors have used fractional-slot concentrated windings in SPMSM, in order to improve motor performance at high speeds. However, it is not common to use fractional-slot concentrated windings for IPMSM, due to the possible increase of torque pulsation. In the second part of this thesis, a fractional-slot is designed for an IPM machine to increase the machine inductance, which improves the flux-weakening capability of the machine. First, the concept of concentrated windings is introduced. Then, a detailed analysis is presented which explains the potential of fractional-slot concentrated winding in IMPSM flux-weakening. Then, the criteria for choosing the optimum slot/pole combination are described. An interior PM 12slot/10pole prototype with concentrated windings has been designed. Simulation results verifies that a very wide speed range of constant power operation can be achieved in this method while achieving machines eff Keywords: Flux-weakening, Interior permanent magnet synchronous machines, Fractional-slot concentrated winding, Rotor shape design, Segmented magnet.
