Design of a permanent magnet-biased reluctance valve actuator with integrated eddy current damping

Abstract

In hydraulic control valves, fast-switching electromagnetic actuators are commonly applied. A low-power, passive holding force is obtained by including a biasing permanent magnet. Meanwhile, valve lifetime improvements require impact velocities close to soft-landing. As an alternative to position control, this paper proposes to integrate passive eddy current damping into the valve actuator. Alternative solutions to generate sufficient eddy currents are explored, including inserting conductive materials at locations of high magnetic field gradient, and short-circuiting the actuation coil. Impact velocities are reduced by 24.7% to 1.62m/s, while respecting the limited transition time.