Modeling of a passive dI/dt limiter

The authors introduce a composite magnetic device which can be used as a rate of current change (dI/dt) limiter. This device can be designed to have a low inductance at currents below a certain threshold level, and a much higher inductance at currents above this threshold. A simplified model of this device is used as the basis for the derivation of a set of performance equations. The results obtained from the simple model are compared to simulations performed with a finite-element package, and to a simpler analytical hyperbolic model. The models are in good agreement if the number of segments becomes large. Although the dI/dt limiter considered has only a single winding turn, additional design flexibility may be had by treating the number of turns as a variable