A Novel “Pseudo” Direct-Drive Brushless Permanent Magnet Machine

Abstract

For low-speed electrical machine applications, it is usually weight/size and cost effective to employ a high-speed machine together with a mechanical gearbox. However, the disadvantages associated with magnetic gearboxes can be overcome by mechanically and magnetically integrating a magnetic gear and a permanent magnet brushless machine, to create a ldquopseudordquo direct-drive machine. It is shown that a torque density in excess of 60 kNm/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> can then be achieved, at a power factor in excess of 0.9.