A novel method for mitigating the capacitor switching-on transients

There are two major switch-on transient phenomena of the capacitor: one is the transient over-voltage and the other is the inrush current. The transients will shorten the lifetime of the capacitor and furthermore they will damage the contactors of the switching device. In this paper, a novel method for mitigating the capacitor switch-on transients is developed. The operation principle of the proposed limiter can be classified into the restrictive mode and the freewheeling mode. During the restrictive mode, the proposed limiter provides high impedance at the instant of switching on to restrain the capacitor switch-on transients. During the freewheeling mode, the voltage across the capacitor is nearly to the voltage source so that it is not necessary to increase the capacitor´s voltage rating. Experiments and simulations are carried out to demonstrate the feasibility of the proposed circuit in this paper.