Radial forces and vibration analysis in an external‐rotor switched reluctance machine

In external‐rotor electric machine configurations, the rotor can be the major source of noise. This study analyses the distribution and the effects of radial forces and vibration in a 6/10 external‐rotor switched reluctance motor designed for an E‐bike application. The distribution of the electromagnetic force vector depends on the switching sequence, the geometry of the motor and the direction of rotation. Therefore, the effect of the switching strategy on the rotor radial force waveform has been analysed. It is shown that adjusting the turn‐on angle can reduce the high rate of change of radial force waveform at the pole corners. The effect of switching angles on the reduction of rotor vibration has also been examined.