Model approach for electromagnetically excited mechanical vibrations in direct-drive wind turbines

Abstract

In this paper a multi-physical modelling approach for calculating parasitic magnetic force excitations in wind turbine generators is presented. These parasitic excitations are dependent on the magnetic field distribution in the air gap and the air gap geometric shape, which is dependent on the external loads of the wind turbine. With this methodology mechanical multibody simulation is coupled with electromagnetic field calculation by means of finite-element calculation. First the general methodology and the calculation of the air gap width distribution is presented and subsequently the electromagnetic field and force calculation is explained.