Long-term stable magnetorheological fluid brake for application in wind turbines

In this article, a novel brake for application in wind turbines developed with the focus on long-term stability is proposed. The brake, whose transmission of power is based on magnetorheological fluids, is designed for fail-safe operation under industrial standards. The long-term stability performance over a lifetime of up to 20 years can be ensured by the use of a Taylor-vortex flow in idle mode that causes a mixing effect for preventing particle separation. Beside a detailed description of the design, long-term measurements with requirements for use in wind turbines emulating a timely reduced aging of the magnetorheological fluid will be presented by applying Hardware-in-the-Loop simulations. The results show an outstanding torque performance over an emulated lifetime of 20 years of use in wind turbines that outpaces the capability of conventional brakes whose power transmission is based on dry friction.