A Design Model of Core Snubber for EAST NBI

A transformer type iron core snubber, as a protective device against the stray capacitance during the breakdown in EAST, is analyzed in detail. Three kinds of topology are presented. Then with the analysis for equivalent circuit, the ranges of three key parameters, i.e., secondary side resistance, leakage inductance and snubber inductance, are determined. By considering the saturation of the magnetic material, a design principle is also presented. A nearly 1:10 core snubber is tested. It is proved that a high permeability core with secondary resistor can restrain the discharge current effectively.