Magnetic component and core specialist TCT of France has collaborated with Belgian semiconductor company e-peas to develop a self-powered AC current sensor using TCT’s magnetic core as an energy harvester based on inductance.
The innovative device not only measures and transmits current and energy flowing through a main AC wire but also operates self-sufficiently by harnessing the electric energy radiated by the AC cable. By combining the Rogowski coil with e-peas’ energy harvesting power management integrated circuit, the sensor generates sufficient energy to measure and transmit its data to a local hub via a LoRawan connection, making it maintenance-free and easy to install.
The set up utilizes a compact TCT current generator, plus an e-peas AEM30940 power management IC. Through induction, the current generator extracts energy from an AC electrical cable. The AEM30940 and accompanying rectifier circuitry then converts this into DC current to power humidity, temperature and light sensor devices, as well as a wireless transceiver.
E-peas, which stands for “electronic portable energy autonomous systems” specializes in providing semiconductor-based ambient energy managers and microcontrollers for energy harvesting and processing solutions designed to give infinite battery life to wireless devices.
Energy harvesting thanks to the magnetic field on a power conductor
TCT’s energy harvesting is based on a circular electromagnetic harvester around a cable. The current flowing through a conductor creates a magnetic flux in the core. A secondary winding placed around the core transforms this flux variation into a voltage and/or current that can be used as a power source. The type of winding, the size of the core and the material are chosen and adapted according to the requested power and the current range in the power conductor.
Recent progress in integrated circuit consumption, driven by the needs of the Internet of Things (IoT), offers new perspectives, the company notes. Previously, energy harvesting was negligible compared to circuit consumption. Today, new generations of components make it possible to consider energy harvesting to significantly improve the energy efficiency of an application or to simply eliminate the use of batteries in certain devices such as wireless IoT sensors. Applications include measurement of instantaneous current, temperature, humidity and other parameters.
TCT – Tores Composants Technologies – manufactures an extensive range of wound passive components and magnetic cores. Located in Sauvigny-les-Bois in central France, it began in 1970 as the magnetic core department of what is now ArcelorMittal.
Today, it operates as an independent company designing and manufacturing magnetic solutions for energy, power conversion and transportation as part of France’s Socomec group, a billion-dollar manufacturer of electrical equipment and energy products. TCT has more than 60 employees and annual turnover of about EUR 10 million. For more info, see www.tct.fr and www.e-peas.com.
