振荡浮子是当下波浪能发电装置中的一种典型形式,其能量俘获装置的设计及水动力学分析是波浪能开发利用技术中的一项关键技术。振荡浮子波能发电装置采用液压机构驱动发电机作为PTO系统,研究通过水工物理模型试验的方法,以浮子的水动力性能为主要内容,讨论了浮子在波浪场作用下的运动状态,以及考虑PTO后浮子的运动特性。通过两者对比,得出了振荡浮子在液压式非线性PTO作用下运动性能,为该类装置的实用化设计提供了参考依据。

Oscillating buoy device,also known as point absorber,is a kind of typical wave energy converter(WEC)that has been widely developed.The advantage of the device is obvious for its simple structure and less cost.In the process of research and development of oscillating buoy,the design and hydrodynamic analysis of the part of energy absorbing structure is one of the key technical problems.The purpose of this paper is to find out the hydrodynamic performance of the oscillating buoys under the action of both wave and power take-off(PTO)system,with an emphasis on PTO effects on the motion of buoys.The oscillating buoy WEC introduced in the paper is equipped with four gyro-shaped absorbers and a hydraulic PTO system driving the generator.By the means of physical model experiment,the time history curves of the buoy motion in different regular waves and under the cominbed wave-PTO effect are given.Compared with the buoy motions without PTO effect,the movement amplitude,speed of buoys with a non-linear hydraulic PTO system decrease to about half.It means that PTO system makes a damping effect on the movement of buoy.The primary stage and second stage in the energy conversion of oscillating buoy WEC are involved in the research.It is found that the system pressure fluctuates with the wave motion and cannot be kept at a stable level.As a result,the energy output of the device is unstable and periodically repetitive,which leads to small capture width and low conversion efficiency.Therefore,a energy storage system such as accumulators with relevant control strategy is recommended to be applied into the hydraulic system in the second stage of the energy conversion.The results of the physical model experiment offer valuable suggestions to the practical design of this type of WEC.