Analysis and design of V-spoke ferrite interior permanent magnet machine for traction applications

Due to the low residual flux density of ferrite magnets, flux-focusing and multi-layer configurations have been deployed to harness both the permanent magnet torque and reluctance torque. Here, a new configuration featuring a V-spoke rotor structure embracing a combined configuration of the conventional V- and spoke-shaped interior permanent magnet (IPM) machines is proposed for its superior torque density over equivalent counterparts. The magnetic open-circuit characteristic of the V-spoke machine is first analysed and compared with that of the equivalent V- and spoke-shaped machines. Then finite element analysis (FEA) simulations are performed for on-load conditions to confirm the superior performance of the proposed design. The frozen permeability method is carried out to provide further insights into the torque production mechanism. Operating efficiency, torque profiles and power-speed performance are also be investigated and evaluated to confirm the utility of the proposed ferrite machine design.