Fractional-Slot PMSMs with One Coil Parallel Branches Made Phases: Topological Characterization and Circulating Harmonic Currents Rejection

The paper deals with fractional-slot permanent magnet synchronous machines(FSPMSMs) equipped with phases made up of one coil parallel branches, with emphasis on theirfaculty to reject the harmonic currents circulating in the loops yielded by the phase parallel branches.These exhibit attractive potentialities, especially their enhanced open-circuit fault tolerance capability.Furthermore, these topologies are suitably-adapted for low-voltage power supply that makes themviable candidates for possible integration in the 42V automotive technology. This potentiality isfurther highlighted in battery electric vehicles where the passenger safety is greatly improved in caseof accidents thanks to the reduction of the DC bus voltage. The study is initiated by a star ofslots-based topological characterization of the FSPMSMs that make it possible the arrangement of thearmature phases according to one coil parallel branches, considering the cases of odd and even num-ber of phases, arranged in double and single layer slots. Then, the star of slots approach is extendedto the investigation of the back-EMF harmonics in order to check the possible circulating harmoniccurrents.