Design and Analysis of a Permanent Magnetic Bearing for Vertical Axis Small Wind Turbine

An interest toward zero frictional losses for small wind turbine is gaining popularity because of a considerable portion of the energy is lost due to friction in the ball bearing. The concept of levitation caused by repulsion of opposite pole in the permanent magnet reduced the friction between the stator and wind turbine rotor, so that the net power output of the turbine increases. The problem associated with usage of this kind of Passive magnetic bearing is its low load carrying capacity and low stiffness. To improve the load carrying capacity and stiffness, numerical simulation has been done for four different configurations. It is found that the stiffness is improved by stacking the magnet in the special combination of different radial cum axial direction of magnetization. The best configuration based on this analysis is fabricated and tested in the vertical axis wind turbine.