Performance Evaluation of Sinusoidal-Flux Reluctance Machine for Improving Power Density with Reduced Torque and Input-Current Ripples

Reluctance machines are attractive for vehicle propulsion for being free from the permanent magnets, although conventional reluctance machines, such as the synchronous reluctance machine (SynRM) and the switched reluctance machine (SRM), suffer from low power density or large input-current and torque ripples. To solve these problems, a recent study has proposed the sinusoidal-flux reluctance machine, which is operated with the sinusoidal phase flux waveform. This preceding study has confirmed the operating principle of this machine, although little information has been provided on the performance compared to the existing reluctance machines. The purpose of this study is to elucidate the benefits of the sinusoidal-flux reluctance machine compared to SynRM and SRM. This study experimentally tested the performance of the sinusoidal-flux reluctance machine, SynRM, and SRM, designed under the conditions of the same stator core and the same rotor outer diameter. The experiment revealed that the sinusoidal-flux reluctance machine can reduce the peak flux compared to the SynRM with smaller toque and input-current ripples than the SRM, suggesting that the sinusoidal-flux reluctance machine is promising for vehicle propulsion.