Application of magnetic power-split device / CVT to variable speed wind turbine for wind power generation

Abstract

For high power generation of future offshore wind turbine application, size and cost were the big challenge that must be overcome. Furthermore, the weight of lubrication system and the dimension of the mechanical gearbox must be taken into consideration. To overcome these problems, a new topology approach for wind power generation without mechanical gear is presented. Using magnetic gear coupled mechanically and magnetically with permanent magnet synchronous generator, even under low wind conditions often found inland, and without mechanical gear, the high speed can be reached with this topology. For these, two original ideas have been presented. The first one, deals with magnetic gear generator which contains two rotors, the input rotor and the output rotor. The mechanical energy extracted from the wind turbine is transferred to the input rotor, which is transmitted magnetically to the output rotor. The permanent magnet of the output rotor interacts with the stator windings to produce electromagnetic torque. Thus, the power captured by the wind turbine is transmitted to the grid by the stator winding. The second idea is the use of power-split magnetic gear. The power transmitted to the grid is split between the generated power by the permanent magnetic synchronous generator and the power produced or consumed by the magnetic gear generator. Thus, the dimension of the nacelle will be reduced and the mechanical gear box can be reduced or omitted. Computer simulation results are given to verify the validity of the proposed machine. It appears that the disadvantages associated to future offshore wind turbine can be surmounted using magnetic gear generator.