Predication of Ocean Wave Height for Ocean Wave Energy Conversion System

Abstract

Ocean wave height is one of the critical factors to decide the efficiency of the ocean wave energy conversion system. Usually, only when the resonate occurs between the ocean wave height (ocean wave speed in the vertical direction) and ocean wave energy conversion system, can the conversion efficiency from ocean wave energy into electric energy be maximized. Therefore, this paper proposes two predication methods to predict the future ocean wave height in 1.5–2.5 s. Firstly, the data fitting of real ocean wave height is achieved by the polynomial method, which is beneficial to the predication of ocean wave height. Secondly, the models of the moving average (MA) predication method and auto regressive (AR) predication method are presented by the time series analysis process. Lastly, after the predication of ocean wave height by the MA method and AR method, and compared with the data fitting result of real ocean wave height, it can be found that the AR method is more accurate for the predication of ocean wave height. In addition, the predication results also indicated that the error between the predication value and true value in the future 2.5 s is considered acceptable, which provides enough time to optimize the operation process of the ocean wave energy conversion system by a suitable control method.

Electric Power Flow Control in Double Three-Phase Machines without Shift between Magnetic Axes

“…Furthermore, wave energy conversion systems are applications in which the proposed technique of a quasi-transformer operating mode can be utilized. Specifically, the issue of oscillatory power from the waves, which is present in a certain number of power take-off systems [32], can be addressed through the suggested topology and control. Energy transfer between windings contributes to the reduction of these oscillations.…”