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

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 behaviour of power devices may be thus 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 paper. The symmetry of the inductive coupling interference components is discovered in the waveforms from the PCB Rogowski coil array with continuous electrostatic shielding. This paper proposes a discrete electrostatic shielding structure for the PCB Rogowski coil array, which is validated through switching experiments to have the immunity against both capacitive and inductive coupling interference. The PCB Rogowski coil array with discrete electrostatic shielding proposed in this paper can be used for researches on paralleled chips of power devices, thus providing a foundation for condition monitoring and design optimization of power devices.