A Method for Increasing the Bandwidth of Rogowski Coils Without Changing Their Size

According to published papers on Rogowski coils, the sensitivity of Rogowski coils can be increased by using high-density turns and multilayer turns. Low-density turns can increase the bandwidth of the coil but can also reduce the anti-interference ability of the coil. The shielding layer can also increase the anti-interference ability of Rogowski coils. However, for Rogowski coils with high-density turns, using a shielding layer or multilayer turns will reduce their measurement bandwidth. To increase the application flexibility of a Rogowski coil, this article proposes a method capable of increasing the bandwidth without sacrificing size, sensitivity, anti-interference, and measurement accuracy. In this method, coils are segmented without reducing the number of turns, and the induced voltage of the segmented coils is output through the voltage followers and joined together by an adder. Seventeen Rogowski coils are wound by an automatic coil winding machine. These 17 coils consist of single-layer coils, double-layer coils, coils without a shielding layer, and coils with a shielding layer. The method is verified for use with Rogowski coils when measuring the sinusoidal current and the turn-on/off pulse current of an high voltage-insulated gate bipolar transistor (HV-IGBT) collector. The measurement errors of this method and the error compensation method are also explored both theoretically and experimentally.