Bandwidth Compensation Method for Rogowski Coil for the SIC MOSFET

Compared with Si based devices of the same grade, the SiC MOSFET has a higher switching frequency, and its speed can reach ns level in the switching transient process. Therefore, current measuring devices with higher bandwidth should be selected for its transient current measurement. Currently, the bandwidth of commercial Rogowski coil is only 30 MHz, which cannot meet the switching frequency of the SiC MOSFET, resulting in inaccurate measurement results. In order to solve the problem of accurate measurement of transient high equivalent bandwidth current in the SiC MOSFET switching, a high frequency bandwidth compensation method for low bandwidth Rogowski coils is proposed in this paper. Based on the analysis of deconvolution theory, the error correction curve of Rogowski coil is obtained on the experimental platform of measurement reference system, and then the high frequency compensation is realized for the bandwidth of Rogowski coil. Finally, the experimental verification is completed on the double-pulse test platform. Experimental results show that the method proposed in this paper can effectively improve the measurement accuracy and the available frequency range of Rogowski coil.