Abstract: Wave energy converter (WEC) includes an energy harvesting system and a power take-off (PTO). The PTO of a floating WEC is the key that converts wave energy into other forms. A set of hydraulic PTO, which is designed for the floating WECs, includes hydraulic cylinders，hydraulic motors, a pressure-maintaining energy storage system, a hydraulic control system and a generator. The hydraulic control system adopts a special “hydraulic self-control system” to control the hydraulic system to release energy under the maximum pressure, or to storage energy under the minimum pressure. During experiments, the maximum pressure is enhanced to 23 MPa, the minimum one to 9 MPa. Comparison between the new hydraulic system and the previous one, quite a few experiments’ data show that the new has evidently improved in efficiency and reliability. The result has great significance in the research and development of WEC prototype.

Key words: Conversion efficiency, Hydraulic control, Hydraulic power take-off, Second transfers