Frequency Characteristics Analysis of Improved Square PCB Rogowski Coil Used in Press-Pack IGBT

Printed circuit board Rogowski coil (PCB RC) has been generally applied in conditions of fast switching speed like power electronic devices, where the chips are arranged very close to each other. For Press-Pack IGBT (Insulted Gate Bipolar Transistor), the square Rogowski coil is very suitable to fit the shape of pedestal because the space is limit to be embedded in and the size of Rogowski coil is desired to be smaller. However, the measurement accuracy of traditional square Rogowski coil is not good enough since the wiring is not uniform, which causes big error when the chip current gathers at the corners of pedestal. In this paper, the improved square PCB RC is proposed to make the mutual inductance inside the chip more evenly, thus the measurement accuracy is improved significantly. The variation of coil parameters with frequency is also studied through simulation and experiment. The improved square Rogowski coil satisfies the accuracy and bandwidth demand of Press-Pack IGBT and is very suitable to be used in.