Power Supply Based on Inductive Harvesting From Structural Currents

Abstract

Monitoring infrastructure offers functional optimisation, lower maintenance cost, security, stability and data analysis benefits. Sensor nodes require some level of energy autonomy for reliable and cost-effective operation, and energy harvesting methods have been developed in the last two decades for this purpose. Here, a power supply that collects, stores and delivers regulated power from the stray magnetic field of currentcarrying structures is presented. In cm-scale structures the skin effect concentrates current at edges at frequencies even below 1 kHz. A coil-core inductive transducer is designed. A fluxfunnelling soft magnetic core shape is used, multiplying power density by the square of funnelling ratio. A power management circuit combining reactance cancellation, voltage doubling, rectification, super-capacitor storage and switched inductor voltage boosting and regulation is introduced. The power supply is characterised in house and on a full-size industrial setup, demonstrating a power reception density of 0.36 mW/cm 3 , 0.54 mW/cm 3 and 0.73 mW/cm 3 from a 25 A RMS structural current at 360 Hz, 500 Hz and 800 Hz respectively, corresponding to the frequency range of aircraft currents. The regulated output is tested under various loads and cold starting is demonstrated. The introduced method may enable power autonomy to wireless sensors deployed in current-carrying infrastructure.

Application of Automatic Motor Control System Based on Sensor Technology

“…Inductive sensor is mainly used to detect objects with metal properties. It is characterized by high repeatability, high positioning accuracy, high action frequency, convenient installation, applicable to various environments, and can be widely used in industrial production [11]. It is mainly composed of LC high-frequency oscillation, signal processing, and switch amplification circuits, as shown in Figure 2.…”

Inductive Power Line Harvester With Flux Guidance for Self-Powered Sensors

“…Based on the study presented in Section 2 as well as on analysis, simulation and experimental results of [17,19,22,23,28], a clip-on, wrap around inductive energy harvesting transducer was fabricated. The longer semi-cylindrical core was implemented using a 0.5 mm thick Ni-Fe alloy sheet, with 80%…”

“…inside and outside the conductor respectively. The 300 Hz, 500 Hz and 800 Hz values were selected in correspondence to aircraft sensing use cases, in which the operating frequency of power lines lies in the 360 Hz to 800 Hz range [26,27]. The skin effect is visible in the grayscale current density field at 500 Hz and, more pronounced, at 800 Hz.…”

“…the body return current path of vehicles including aircraft) have been studied in [17,19,21]. A power supply including power management and supercapacitor intermediate storage based on this method, and developed for an industry-defined aircraft use case, was demonstrated in [22] and a further study of magnetic funnelling on a similar device was reported in [23]. A prototype of around 100 cm 3 developed for railway applications was demonstrated to provide 40 mW at 250 mm distance from a 200 A, 50 Hz emulated railway structural current in [24].…”

Autonomous Electrical Current Monitoring System for Aircraft

“…Aircraft sensor systems powered by heat [26][27][28][29], vibration [30], flow [31], static charge [32] and by inductive coupling to the electrical power network [33][34][35][36] have been considered. Inductive power transfer methods [37,38] have also been implemented.…”