Design of a Multilayer PCB Bus for Medium Voltage DC Converters

In this work, the design of a planar PCB-based power bus for operation at 6 kV is presented. A previous reported bus which reduced electromagnetic interference (EMI) was redesigned to allow use of Wolfspeed's 10 kV XHV-6 and XHV-9 modules. A design method to control the peak electric field (E-field) in high field strength regions was then used to ensure the field strength in air and the PCB dielectric remain within an acceptable range. Using this method, adding a 1mm negative offset between the +/- DC power plane and MID conductor provided a 13% reduction in field strength alone with no other changes. Other optimization steps were taken to further reduce peak fields. The field strength in air was most efficiently controlled adding and external core to what would typically be the outermost layers of the PCB.