Novel permanent magnet machines using Halbach cylinders

This paper describes various permanent magnet machines using Halbach cylinders (arrays), from using pre-magnetised anisotropic magnet segments having varying magnetisation orientations, to those moulded as bonded isotropic or anisotropic NdFeB ring magnets, which are subsequently impulse magnetised using a magnetisation fixture which produces a sinusoidal MMF distribution. Three possible magnetisation fixture designs are described. Various Halbach cylinder machine topologies are then reviewed, including radial and axial field, slotted and slotless, rotary and linear (tubular and planar) permanent magnet machines with and without rotor and/or stator back-irons. The paper also reviews their typical applications, ranging from integrated motor and generator in flywheel applications, linear motors with ultra high acceleration, ultra high speed motors, multi-axis rollers, high performance servo drives, to passive magnetic bearings and magnet powder alignment system