Study of a Semi Active Electromagnetic Regenerative Suspension

The main objective of this work is the theoretical and numerical study of a device that allows recovering energy from an automobile suspension. In place of the viscous damper, which dissipates the kinetic energy of the vehicle due to rough roads or more marked obstacles, an electromagnetic damper performs the functions of the viscous shock absorber with a recovery of electric energy. The damper has permanent magnets and its working is based on the electromagnetic induction. The used ferromagnetic material is the Supermendur, which has very good ferromagnetic properties, but is expensive and difficult to found, so that the choice of different material is useful to reduce the costs. The mathematical model describes the operation of the damper, restoring the values of the electrical and mechanical magnitudes versus the relative speed between the stem and the stator. Several finite element analyses, conducted in ANSYS Workbench Magnetostatic, confirm both the magnetic field and flux values obtained through the theoretical analysis. A calculation example of the energy recovery is done considering an electric minicar transiting on a bumpy road (IRI=3); the recovered power has a total value of 280W about; at last a comparison with similar devices proves the excellent quality of the design also if the comparison should be done with uniformity of the parameters.