Impact of Turns Number of Square PCB Rogowski Coil for Measuring Chip Current of Press-Pack IGBT

Printed circuit board Rogowski coil (PCB RC) has been widely applied in conditions of fast switching speed like power electronic devices, which brings great challenges to the bandwidth of the current sensor. Usually, the bandwidth of PCB RC can be greatly improved by decreasing the number of turns. However, the negative effect is the measurement accuracy will be reduced as well when the turns number increases. In this paper, the turns number of square PCB RC used in Press-Pack IGBT (Insulted Gate Bipolar Transistor) is studied in detail, which considers the bandwidth and the measurement accuracy at the same time. The calculation and simulation results show that both the measurement accuracy and bandwidth are less sensitive as the turns number increase, thus PCB RC with more turns is a good idea to enhance the signal-to-noise ratio. The effectiveness of square PCB RC with 40 turns is verified by the double pulse test results compared to the commercial current sensor.