Permanent magnet modules and rotors

A permanent magnet module for a permanent magnet rotor, the permanent magnet rotor comprising a rotor rim and a plurality of permanent magnet modules arranged on the outer or inner circumference of the rotor rim, the permanent magnet module extending generally along an axial direction and being of substantially constant axial-cross section, the permanent magnet module comprising:

• a base adapted to be fixed to the rotor rim and a central magnet structure, the central magnet structure comprising a central magnet support structure and one or more permanent magnets adjoined to the central magnet support structure,
• wherein the base and the central magnet structure comprise a plurality of radial holes, each hole of the base aligned with each hole of the central magnet structure, respectively, and wherein the central magnet structure is fixed to the base by a plurality of bolts inserted in the radial holes,
• wherein the central magnet structure is adapted so that, upon deformation as a result of the bolts being inserted in the radial holes to fix the central magnet structure to the base, at least a portion of a first and a second surface of each permanent magnet are substantially in conforming contact with a surface of the base and with a surface of the central magnet support structure, respectively.