Abstract

Brushless DC- and AC-permanent-magnet motors controlled by powerful micro-controller electronics have opened up a significant share of the small motor market in the last years. Based on the mechanical low cost construction of single-phase motor the paper presents electronic drive concepts to improve the performance and for special applications also the lifetime of brushless motors. The tangential and radial forces acting on the rotor are controlled by special phase current curves to reduce the torque ripple and to avoid expendable machinery parts like ball or sliding bearings.