Recently, maintenance applications around power lines have been actively studied. These applications usually supply power through magnetic energy harvesting(MEH) to devices around the power line. The magnetic field energy harvesting method has many advantages compared to other energy harvesting methods, but has a problem of low power density due to saturation of the magnetic material. In particular, in the power line environment, it is important to overcome the saturation phenomenon of the magnetic material, which is the cause of the low power density in a wide current range.
In this paper, we propose a design methodology to harvest maximized output power by considering the saturation effect. To consider magnetic saturation, the output power model and the saturable magnetizing inductance model based on magnetizing current were comprehensively analyzed. Additionally, the critical point of saturation for the maximum harvested power was analyzed by considering different primary side current conditions. In addition, from a practical point of view, we analyzed problems such as the temperature rise of the magnetic material, the wide current range of the primary side, and the influence of the power line due to the installation of the harvester.
With the proposed design methodology, the accuracy and efficiency of the output model were verified with experimental results compared to the conventional model. To consider the real environment, a 150 kW class of AC resistor load bank was implemented to control the primary current from 0 to 100 A with power frequency of 60 Hz. Experimental results show that the proposed method can harvest an average power of 14.32 W on 70 A power line, which is an increase of 39.8 % compared with the conventional design method.