Optimal Configuration of Single-Layer Domino-Coils With Uniform Spacing for Online Monitoring Equipment in Smart Grid

Domino-coils wireless power transfer (WPT) technology has emerged as an effective means of ensuring reliable power supply for online monitoring equipment in smart grid. Nonetheless, it encounters persistent challenges when integrating domino-coils into composite insulators, notably the issues of large coil size and low power transmission efficiency (PTE) over medium and long distances. In response, this article constructs a T equivalent model of domino-coils WPT system to deduce the optimal efficiency condition for any number of coils. Specifically, it is determined that PTE is maximized when the current ratio of nonadjacent coils equals the mutual inductance ratio of adjacent coils. Building upon this insight and considering practical constraints such as coil volume and transmission distance, an optimization model is formulated for single-layer domino-coils with uniform spacing under the optimal efficiency condition and given output power specification, which is subsequently determined using a particle swarm algorithm. Experimental validation is conducted utilizing a seven-coil system experiment platform, achieving an output power of 12.23 W and a PTE of 85.94% at a transmission distance of 50 cm. These findings demonstrate significant enhancements in PTE, coil volume reduction, and ease of integration into thin and uniformly distributed insulator.