Analytical Formula to Estimate the Maximum Inrush Current

Abstract

This letter presents an analytical formula to predict the peak inrush current for a nonlinear inductor in series with a resistor. The formula is developed using nonlinear circuit analysis and its accuracy is verified by comparing the calculated peak inrush current to those obtained through time-domain simulations. The formula is very useful to estimate the impact of damping resistors on the transformer inrush current.