Optimisation of magnetic gears for large wind turbines

An analytical model for the prediction of the magnetic field distribution in the airgaps and permanent magnet (PM) regions of a large radial magnetic gear (MG) is presented. The model is employed for the optimisation of a MG for a large wind turbine. Due to its size, the MG consists of a number of identical circumferential sections, and it is shown, that the number of sections could have a significant effect on the torque transmission capability and the active mass of the MG. It is also shown that design parameters, such as the gear ratio, direction of magnetisation and the pole-arc to pole-pitch ratio of the PMs can have significant effects on the performance of the MG.