PCB Rogowski Coil Array With Discrete Electrostatic Shielding for Current Measurement of Paralleled Chips in Power Devices

A printed circuit board (PCB) Rogowski coil array is capable of measuring the currents of the paralleled chips inside power devices; the operating status and failure behavior of power devices may thus be monitored. The conventional continuous electrostatic shielding provides immunity to capacitive coupling interference for the PCB Rogowski coil array but fails to suppress inductive coupling interference. Equivalent circuit models of the PCB Rogowski coil array with continuous electrostatic shielding are established and the influence mechanism of the inductive coupling interference on the Rogowski coil array is analyzed in this article. The symmetry of the inductive coupling interference components is discovered in the waveforms from the PCB Rogowski coil array with continuous electrostatic shielding. This article proposes a discrete electrostatic shielding structure for the PCB Rogowski coil array, which is validated through switching experiments to have immunity against both capacitive and inductive coupling interference. The PCB Rogowski coil array with discrete electrostatic shielding proposed in this article can be used for research works on paralleled chips of power devices, thus providing a foundation for condition monitoring and design optimization of power devices.