Improvements of Voltage Distribution in Inductor Windings by Additive Manufacturing

Abstract

Higher switching frequencies and faster switching speeds in power electronics were realized as a result of using wide bandgap (SiC, GaN) devices. Higher <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{dV}/\text{dt}$</tex> across an inductor can cause higher voltage stress and less uniform voltage distribution across its turns. Thus, inductor winding insulation can be at risk in medium or high voltage applications under high <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{dV}/\text{dt}$</tex> . In this work, additive manufacturing is utilized to fabricate the inductor winding and optimize the parasitics. In this way the voltage stress is distributed more evenly across the inductor winding. A <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$20 \text{kV}$</tex> inductor is developed to showcase the proposed approach. Experimental results show that the peak voltage stress between inductor turns has reduced by over 10%. Also, the maximum voltage stress difference between inductor turns has reduced 67%.