Studies on Variable Liquid-Column Oscillator for High Efficiency Floating Wave Energy Conversion System

J. Ocean Eng. Technol. 2009;23(5):15-24.

Yang Dong-Soon,Cho Byung-Hak

Green Growth Laboratory KEPRI,Green Growth Laboratory KEPRI

가변 수주진동장치를 이용한 고효율 파력발전에 관한 연구

양동순,조병학

한전 전력연구원 녹색성장연구소,한전 전력연구원 녹색성장연구소

Keywords: Wave energy conversion, Variable liquid column oscillator, Control law

핵심용어: 파력발전, 가변수주진동기, 제어법칙

Abstract

The results of a simulation study of variable liquid column oscillations in U-tanks with a novel control scheme are presented. The configuration under investigation is analogous to that of the tuned liquid-column damper used to suppress oscillatory motion in large structures like tall buildings and cargo ships. However, by virtue of an adequate controller, the response of amplitude of the U-tanks becomes larger in a desired frequency range. The motion of wave energy conversion system equipped with a variable liquid column oscillator is described by a series of nonlinear differential equations. The equations describe the motion of body under ocean wave excitation, and the motion of liquid with an air-spring effect caused by the compression and expansion of air in vertical liquid columns and air chambers. It is shown that the effect of the air-spring has a vital role to maintain the natural frequency of oscillation in the system to synchronize with the frequency of the ocean wave, thus the system provides the most effective mode for energy extraction from the ocean.