Influences of Parasitic Capacitances in Wide Bandwidth Rogowski Coils for Commutation Current Measurement

This paper focuses on the capacitive coupling of PCB integrated Rogowski coils for commutation current measurement. It investigates the cause and the influence of parasitic capacitances on the measurement signal. It discusses the advantages of a differential winding arrangement and the reasons why shielding is not an option in this application. The parasitic capacitance of three different winding arrangements are measured and compared to a Rogowski coil approach with minimized parasitic capacitance. On the base of sensor prototypes, the influence on the measurement is investigated in a pulsed current source.