Influence of motor design and feed-current waveform on torque ripple in brushless DC drives

A general relation for the instantaneous torque developed by a convertor-fed synchronous motor for known phase current waveform and the field flux distribution is formulated. The influence of these quantities, together with other parameters such as phase number, on torque ripple is discussed with the aid of tabulated predictions for a number of typical cases. Techniques for the achievement of low values of torque ripple are outlined.