Study of Passive Magnetic Bearings for Vertical-Axis Wind Turbines

The increasing world energy demand as well as the necessity of environmental clean developments has turned the industry attention to improvements in renewable energy. In this context, wind power plants present technological advantages as an excellent source of clean energy. The current vertical-axis wind turbines are going to be a novel energy supplier in urban centers due to both low-cost and low-impact architectural design. Moreover, they have good performance even in the presence of turbulent winds. A magnetic suspension can greatly improve the performance, expanding the operating points to very low wind velocities. Active magnetic bearings present limiting factors such as power consumption and complexity of the system, due to sensors, power electronic circuits and the control system. In other way, passive techniques, which use permanent magnets and/or superconductors, can be alternatives in some applications. This paper presents a contribution to the design of passive magnetic bearings for vertical-axis wind turbines. Finite element simulations and experimental data will be presented.