The McGill/MIT direct drive motor project

Abstract

A direct drive electromagnetic motor and associated controller have been designed and constructed to improve upon the torque-to-mass ratio and torque accuracy of previous designs. The goals are a torque/mass of 10 N m/kg and a torque ripple of less than 1% at full-scale torque. The motor design is a 3-phase synchronous motor, with an axial airgap and identically wound armatures. Both armatures are water cooled to increase the allowable current density. A table-based microprocessor controller shapes the current profiles in the phases to correct for torque ripple.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>