Mathematical Current Derivation for Acoustic Noise Reduction in Switched Reluctance Motors

This article presents the mathematical derivation of the current waveform that flattens the radial-force sum in switched reluctance motors. The proposed current waveform is mathematically derived, thus no numerical computation is required. Additionally, the proposed current waveform contains the phase shifts of the harmonic components. The proposed current makes the radial-force sum flat, in addition to reducing the torque ripple and the current rms value compared to previously proposed waveforms. The mathematical derivation of the proposed method imposes a negative part of the current, hence current flipping is introduced. Since the proposed method is mathematically derived, it is applicable to various switched reluctance motors. The proposed method was validated by finite element analysis and was experimentally verified on an 18/12 switched reluctance motor designed as a generator for hybrid vehicle applications.