Design and Analysis of a New Type of Electromagnetic Damper With Increased Energy Density

Eddy current dampers, or electromagnetic dampers, have advantages of no mechanical contact, high reliability, and stability, but require a relatively large volume and mass to attain a given amount of damping. In this paper, we present the design and analysis of a new type of eddy current damper with remarkably high efficiency and compactness. Instead of orienting the magnetic field in a uniform direction, we split the magnetic field into multiple ones with alternating directions so as to reduce the electrical resistance of the eddy current loops and increase the damping force and damping coefficient. In this paper, an analytical model based on the electromagnetic theory for this type of eddy current damper is proposed, and a finite-element analysis (FEA) is carried out to predict the magnetic field and current density. Experimental results agree well with the analytical model and FEA predictions. We demonstrate that the proposed eddy current damper achieves a damping density $(Ns/mm3)$ and a dimensionless damping constant as much as 3–5 times as those in the literature. The dependence of damping on velocity and frequency is also examined.