Dynamic investigation of 650 W roof-top horizontal wind turbine rotor system supported by radial permanent magnet bearings

Abstract The present work focuses on the rotor dynamic properties of a 650 W roof-top horizontal axis windturbine (HAWT) rotor supported by radial permanent magnet bearings (PMBs). Radial PMBs were designed and optimized concerning the rotor of a wind turbine for maximum stiffness. Initially, a generalized design and optimization process for multi-ring radial PMBs (MrRPMBs) with a radial air gap is presented to get the maximized force and stiffness per magnet volume. The proposed mathematical model is validated using the Finite Element (FE) analysis tool Ansys for chosen rotor dimensions. Then, the same optimization technique was extended for HAWT rotor bearings to extract the optimized multi-ring radial bearing parameters. The dynamic investigation is performed to study the effect of bearing parameters on the rotor-bearing modal frequency and dynamic amplitude of a rotor. Firstly, the dynamic investigation was performed for the conventional deep groove ball bearings (DGBs) supported rotor, considering the effect of bearing span length. Secondly, the dynamic response was analyzed for the rotor system through a hybrid bearing set (HBS) by replacing DGB with PMB. Finally, DGBs are completely replaced by radial PMBs. FEanalysis was performed using the Ansys workbench rotor dynamic tool for all the bearing combinations.