Size Reduction of a DC Link Choke Using Saturation Gap and Biasing with Permanent Magnets

This document describes the design procedure of permanent magnet biased DC inductors using the Saturation-gap technique [1]. This biasing configuration can provide a 50% reduction in either the core volume or the number of turns, while meeting its current and inductance requirements. A design example on a 20A 1mH iron laminations DC choke is presented. MEC simulations and empirical measurements on a physical unit were performed. Experimental results show a 50% reduction of the core volume is achieved. The total volume reduction of the inductor is 37%.