Soft magnetic-core coupler suitable for low-frequency band power-line communication

Abstract

In this study, we implemented inductive couplers suitable for low-bandwidth powerline communication and conducted a transmission experiment on a power line of 900m length. The nanocrystalline and ferrite was used as soft magnetic core materials for implementing the toroidal core type and cut-core type couplers. Since the magnetic flux density distribution of the toroidal core is concentrated in the core and the influence of the leakage magnetic flux can be ignored, the insertion loss in the bandwidth range is small. However, in the cut core, the insertion loss in the low-frequency region largely occurs due to the leakage magnetic flux through the air gap. In order to compensate the large insertion loss in the low frequency region for the cut core, the inductance of the core was varied by adjusting the turns ratio of the coupler. We confirmed that when the broadband inductive coupler has a winding ratio of 3:10 or 5:10 and is applied to a narrow band power line communication system, it can communicate at a distance of at least 900 m with a data rate of 9.6 kbps.