A balanced commutator for switched reluctance motors to reduce torque ripple

A method of computing the reference currents for current tracking feedback control, called a balanced commutator, is presented. For a given motor, this commutator reduces the peaks and the rates of change of the reference currents. Although primarily intended for lower-speed direct-drive applications, the commutator design allows accurate current tracking, and therefore reduced torque ripple, over a reasonably wide range of operating speeds. Three motor models, (analytical, numerical, and measured) are considered. Issues relating commutation schemes to amplifier requirements are addressed by simulating simple analytical models of the electrical dynamics. To reveal the interplay between motor design and commutator output, torque models produced by numerical field calculations are considered. To demonstrate the practical benefits and limitations of the method, a balanced commutator based on measured motor data is implemented, and torque ripple reduction is quantified in a laboratory experiment.<
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