Torque Characteristics of SPM-FS Machines With Functional-Contour Salient Pole Rotors Considering Manufacturing Error

To suppress high cogging torque and torque ripple of stator-permanent magnet flux-switching (SPM-FS) machines, three functional-contour salient pole rotors (FSPRs) are proposed and designed, where the rotor tooth top contours conform to <italic>y</italic> = <italic>k</italic>|<italic>x</italic>|, <italic>y</italic> = <italic>ax</italic><sup>2</sup>, and <italic>y</italic> = <italic>A</italic>cos(<italic>bx</italic>) respectively. Firstly, with the help of finite element analysis, optimal geometrical parameters of FSPRs are obtained with minimum torque ripple. Then, the torque ripple suppression rates at unit torque loss of these FSPRs are analyzed by comparing with the initial values from output torque, torque ripple, and cogging torque. Further, considering that the functional-contours of salient pole rotors are easily affected by manufacturing errors, rotor single-tooth three-points model and stator inner circle deviation model are established on the typical manufacturing errors in both stator and rotor. A finite manufacturing error combination is obtained by Latin Hypercube Sampling, based on which the manufacturing error sensitivity of three FSPRs is discussed. Finally, prototypes with three FSPRs and initial rotor are tested to verify the cogging torque suppression capability of three FSPRs. Also, the manufacturing error analysis provides a reference for robustness design and industrial application of SPM-FS machines employing the FSPRs.