Optimum excitation of switched reluctance motors

The paper demonstrates, using an example switched reluctance motor (SRM), excitation waveforms that are optimised in terms of least RMS current for a given mean torque. Two classes of waveform are described: least-current and smooth-torque. The least current waveforms neglect torque ripple, whilst the smooth-torque waveforms eliminate torque ripple. The new classes of waveform are contrasted with the conventional single-pulse and chopping waveforms. Of particular importance is the medium speed smooth-torque, waveform that has a lower RMS current and a similar peak current to its chopping counter part. Thus it is possible to increase the mean torque produced by the SRM and simultaneously smooth its torque production, without increasing the electronics VA rating