Theoretical model of an energy-harvesting temperature sensor device using magnetic moment change

Digitalisation and the incorporation of IT in industries have been gaining increasing interest. With Industry 4.0 and Cyber-Physical Systems on the rise, there is a growing focus on integrating digital twins—requiring an accurate and efficient physical sensor system. The authors propose a novel temperature sensor device that has the potential to solve several crucial concerns when considering digital twin applications with conventional temperature sensors. The proposed device utilises the magnetic moment change accompanying magnetic phase transitions and electromagnetic induction to measure the temperature of a magnetic material while generating electricity through energy harvesting. A mathematical model is formulated for the sensing scheme of the proposed device as a theoretical framework to quantitatively analyse the performance of the proposed device as a temperature sensor for digital twin applications. Furthermore, an experimental investigation of the relationship between the temperature of a magnetic material and the electromotive force induced in a solenoid was conducted to confirm the model’s validity. The results and model demonstrate a strong temperature dependency on the induced electromotive force, especially at temperature regions surrounding the phase transition temperature—revealing the importance of critical parameters to consider when designing devices. Graphical overview of the proposed device. (a) Scheme of the temperature dependency of probe magnetisation. (b) Scheme of utilising electromagnetic induction as a means of measuring magnetisation change. • A novel temperature sensor device using magnetic moment change has been proposed. • A mathematical model representing the sensing scheme of the proposed device has been formulated. • Experimentations on electromagnetic induction shows strong temperature dependency of voltage.