Design of a high power-low voltage multiphase permanent magnet flux switching machine for automotive applications

This work presents the design of a multiphase flux switching permanent magnet (FSPM) motor for automotive applications. The use of a 12 slot/10 pole combination, configured as a six phase machine is shown. Working within the constraints imposed by the available DC voltage (48 V) and the maximum excitation current (300 A rms), two different winding configurations are considered. The first configuration is a conventional star arrangement with six phases, whereas the second configuration arranges the connections to form an electrically independent pair of three phase delta-connected windings. The delta configuration is shown to produce higher output torque and wider field weakening operation region than the star configuration at the system voltages employed in the study. The efficiency of each of the two configurations at different operating points is presented. The differences between the two configurations have been investigated in terms of the torque density, current density, and output power. In addition, the ability to resist demagnetization has been analyzed for both configurations. A simple comparison with some other topologies is also introduced, which indicates that the multiphase configuration shows the potential for higher torque density than 3-phase radial flux machines already used in existing automotive applications. Finite element (FE) analysis was used to validate the design for the given excitation current. Different key performance parameters including the output torque, terminal voltages, flux linkages, and efficiency are introduced and discussed in the context of each winding configuration.