Comments on 'An Effective Power Improving Method of Magnetic Field Energy Harvesters Using a Series-Connected Capacitor for Wireless Sensors in Smart Grids'

In the paper 'An Effective Power Improving Method of Magnetic Field Energy Harvesters Using a Series-Connected Capacitor for Wireless Sensors in Smart Grids' by Y. Li et al. (IEEE Trans. Power Electron., vol. 39, no. 7, Jul. 2024), enhancement of magnetic energy harvester (MEH) performance by adding a series-connected capacitor was discussed. It was shown that the optimal (in terms of harvested MEH power) capacitance value is inversely proportional to the load resistance value. Yet, some functional properties could have been missed out due to adoption of high-permeability ungapped core (without calling into doubt the validity of presented results). Moreover, optimal transfer window length was not obtained. Consequently, the purpose of this comment is two-fold: demonstrating some operational details not highlighted in [1] and complementing it by providing analytical expressions for optimal transfer window length and corresponding harvesting potential of the MEH. Experimental results validate the complementary comments.