Feasibility Study of Passive Electromagnetic Damping Systems

A linear displacement electromagnetic machine is proposed to be used as a passive structural damper. The electromagnetic damper extracts the kinetic energy imparted into the structure by wind or seismic disturbances by transforming it into electricity and induces a force that opposes the movement produced by the disturbance. It is shown that the force-velocity relationship of the electromagnetic damper approximates that of an ideal dashpot with a time delay caused by the circuit reactance. A feasibility analysis is presented to demonstrate the physical and economical viability of the electromagnetic damper as a structural device. The proposed device presents several advantages over current passive structural dampers, among which are: energy dissipation external to the device; possible operation as a semiactive damper by modifying the circuit impedance; and possible operation as an actuator by reversing the energy flow direction.