Experimental Study on Performance Assessment of Hydraulic Power Take-off System in Centipede Wave Energy Converter Considering Caspian Sea Wave Characteristics

Abstract

Considering the characteristics of the Caspian Sea waves, using a centipede wave energy converter might lead to satisfactory performance. The present paper introduced a pilot wave energy converter (WEC) called IRWEC2. Moreover, the performance of the hydraulic power take-off (PTO) system developed for the WEC was assessed experimentally in the wave tank of Babol Noshirvani University of Technology (BNUT). The Simcenter Amesim software was used so as to design the hydraulic PTO system and to initially evaluate the system performance. For two separate buoys were used, different series and parallel configurations were employed for the separate hydraulic cylinders connected to each buoy to achieve the optimum performance of the PTO system. The characteristics of input wave, resistant load, and flow control valve opening were defined as the most important parameters affecting the converter performance. Accordingly, the maximum value of generator output was obtained based on the certain values of these parameters. To validate the processes defined, the simulation results obtained through the Simcenter Amesim software were compared to the experimental ones and a good agreement was found. According to the results, the maximum power of the PTO system was 46 watts (for laboratory scale), which is related to the parallel configuration. In this case, the efficiency of the PTO system was 23%. Moreover, the output of the generator increased by about 12% compared to the case where only one buoy was used.