High Precision Wide Bandwidth DC Current Transducer Based on the Platiše Flux Sensor

Abstract

In the last decade, we observed a noticeable increase in direct-current systems (DC), particularly in solar power generation, grid storage systems, and electric mobility. Some of these systems may require high-voltage isolation and peak currents in excess of kA. The existing standard compact and lower cost current sensing solutions hardly ever achieve an overall measurement uncertainty below 1% mainly due to offsets and hysteresis; their typical bandwidth is about 250 kHz, and they may also be noisy. This article presents a new method of isolated DC and AC current measurement based on a single gapless core and the innovative Platiše Flux Sensor. After verification in a mixed-signal simulator, the method was implemented in a functional prototype of a DC current transducer (CT) and thoroughly tested in a reference setup. The performance tests showed a low offset and hysteresis, a bandwidth in the MHz range, low power consumption, and low noise operation. Furthermore, the low current transducer achieved a typical uncertainty of less than 0.2% and a linearity of less than 200 ppm, which indicates an overall superior performance compared to representative comparable CTs based on alternative technologies. In addition to the areas of application mentioned above, the new type of DC-CT can be used for general purpose metering, measurement instrumentation, and high power DC and AC systems.

Why Should We Test the Wideband Transformation Accuracy of Inductive Current Transformers?

“…However, to fully evaluate its accuracy, the behavior in the rated conditions should be first analyzed in detail [4]. Therefore, many research activities are focused on developing the methods and conditions and measuring setups to perform the wideband accuracy tests [8][9][10][11][12][13]. Until now, the new standards IEC and IEEE have not been developed yet.…”