Feasibility study of ubiquitous sensor networks by inductively coupled PLC over PV power systems

Simple and low-cost PLC will be required to play a role in the Internet-of-Things (IoT) market such as ubiquitous wireless sensor networks. From the viewpoints of temporal connectivity and obtaining high SNR and stable channels, inductive coupling techniques for the kHz band PLC have been proposed in this paper. The results of three feasibility studies using a photovoltaic power system installed in our laboratory have been described. First, an inductive coupler is applied to the DC powerline channel, because it forms a low impedance loop circuit. It was proved that the DC power-line provided a high SNR channel, so that the simple modulation technique was enough to realize the ubiquitous PLC networks. The second topic is the contactless power supply using the same ferrite core as the PLC coupler. It has been shown that the proposed circuit could supply power of 35mW at the maximum to a wireless sensor node. The third topic is an application of the 1-wire PLC system to aerial cables. A suitable coupling method has been proposed to provide a low signal attenuation channel. The noise characteristic peculiar to photovoltaic (PV) power-line is also pointed out, that is the amount of noise on a sunny day with cloud occasionally exceeded that on a cloudless sunny day.