Output characteristics in direct-link wave power generating system considering place of installation

Recently, from the viewpoint of environmental conservation, renewable energy technologies such as wind and solar have attracted significant attention around the world. In particular, wave power is a remarkable energy resource for island nations such as Japan. The energy density of wave power is higher than some other renewable energy sources such as wind and solar. However, conventional wave power generating systems are low efficiency and low power, and their facilities are too large relative to their output power. In this research, a new mechanism that converts wave power into electricity is proposed. It is referred to as a “direct-link” mechanism and consists of a buoy, rack, and pinion. Because of its simple load transfer path, it is expected that the energy conversion efficiency will be higher than that of a conventional wave power conversion system. Surface permanent magnet synchronous generators for the proposed system are designed with different stack lengths considering their installation location. The electrical output characteristics considering the appearance probabilities of waves in Shionomisaki and Habu are calculated using a dynamic simulation. It is shown that the conversion efficiency of the proposed system is remarkably improved over that of a conventional system.