Digital Frequency Response-Based Optically Isolated Wire-Wound Hall Current Sensor Scheme for Sinusoidal Current Waveform Measurement

Abstract

The increasing requirement for reliable power demands robust protection with excellent waveform sensors. The presence of nonlinear elements in the modern-day loads brings challenges in sensing the current waveform, which is different from the conventional sinusoids. This research article proposes a novel current waveform sensing philosophy with the help of five numbers of series-connected wire-wound Hall current sensors. Signal conditioning circuits and their mathematical expressions are also discussed here to estimate the current waveform with 9.6% ± 2.4% linearity and 2.1%/A ± 1.3%/A sensitivity. The sensing technology senses the current waveform with a root mean square error (RMSE) value of 0.2. Apart from sensing the typical sinusoidal current waveform, the proposed sensing philosophy also senses the impulse and switching current waveforms with RMSE values 2.7 and 0.65, respectively. These results have a broad scope of improvement by implementing more wire-wound Hall current sensors in series. Digital output features and the optical link between the sensor and receiver offer necessary isolation to the microcontroller against harmful transients and other waveform distortions. The experimental verification and required data analytics confirm the applicability of the sensor with substantial accuracy, sensitivity, and linearity.