A Novel Nonintrusive Self-Powered Current Sensor With Time-Division Operation

With the development of power electronics converters in power grid, real-time current monitoring, covering both ac current and high frequency harmonics, is important. Nonintrusive current sensing has become a promising solution due to its advantages of portable installation and noninterference with equipment operation. However, current sensors rely on external power supplies, limiting their large-scale application. Nonintrusive, compact and self-powered current sensor becomes a future trend for flexible sensor deployment within the constrained space of power converters. The principle of electromagnetic induction can be employed both for current sensing and energy harvesting. This article proposes a novel dual-coil-single-magnetic core module to realize a self-powered nonintrusive current sensor. Due to different energy and bandwidth requirements for energy harvesting and signal sensing, dual coils with time-division operation strategy are adopted. The designed prototype achieved an output power of 8.18 mW under magnetic field of 50 Hz/300 mu T. Wideband current sensing is verified from 50 Hz to 500 kHz with sensitivity of 0.996 mV/A, which is comparable with commercial product. The proposed dual-coil-single-magnetic core module achieves self-powering and wideband current sensing in nonintrusive applications.