Quantitative comparison of flux-modulated interior permanent magnet machines with distributed windings and concentrated windings

Low speed flux-modulated permanent magnet machines (FMPMs) which are based on 'magnetic-gearing effect' have attracted increasing attention due to their high torque capability and simple structure. In order to assess the potentials of FMPMs in the application of low-speed direct-drive, two flux-modulated interior PM machines with distributed windings and concentrated windings are quantitatively compared by using finite element method. The results demonstrate that the machine with distributed windings can offer higher peak electromagnetic torques and lower torque ripples. Moreover, the machine with distributed windings also present stronger flux-weakening capability and lower power losses. The results also indicates that the magnetic saturation problem should be paid full attention when design flux-modulated interior PM machine with concentrated windings. If this problem can be well solved, the performance of machine with concentrated windings may be improved.