A dynamic model for control purposes of a wave energy power plant buoyancy system

In order to obtain a control system for a wave energy power plant a linear dynamic model of the buoyancy system is presented. The plant ¿Wave Dragon¿ is a floating device using the potential energy in overtopping waves to produce power. A water reservoir is placed on top of the Wave Dragon, and hydro turbines lead the water to the sea producing electrical power. It is important to control the level, heal and trim of the reservoir in order to maximize the power production in consideration of the wave height; here the amount of overtopping water and the amount of potential energy is conflicting. It is possible to control the level, the heel and the trim of the Wave Dragon through pressure adjustments in air chambers. The pressures in the air chambers may be individually controlled by an air fan through an array of valves. The paper presents a linearized model for control purposes describing the dynamics from the air inlet to the level, heel and trim.