Electromagnetic Design and Assembly Analysis of a Halbach Rotor Magnetic Gear for a Marine Hydrokinetic Application

This paper presents the design and analysis of the second stage of a 5kW multistage magnetically geared generator for a marine hydrokinetic generator application. In order to reduce the field harmonics and maximize the torque density, a Halbach rotor typology is utilized. A key feature of the presented magnetic gear (MG) design is the unique magnet arrangement that enables the inner and outer Halbach rotor magnets to be more easily assembled, even with dimensional tolerance inaccuracies. The presented Halbach magnet rotor typology makes use of the internal magnet forces to retain the magnets in position, the presented design also helps with the assembly process. The 3-D finite element analysis (FEA) calculated torque and active region torque density for the design is 227 N.m and 276.5 N.m/L respectively. The experimental assembly is presented.