Power Production Efficiency Improvement of a Point Absorber Type Wave Energy Converter by Model Predictive Control

Abstract

This paper numerically investigates motion and power production characteristics of a point absorber type wave energy converter (WEC) using a model predictive control (MPC). The MPC is able to maximize power production while handling hard constraints, such as maximum motion, control force and so on. Motion and power production characteristics of the MPC were compared with two conventional control methods, the approximate complex-conjugate control with considering the copper loss (ACL) and the resistive loading control (RLC), under the sea condition of Japanese typical joint probability distribution based on a 21-year high-resolution hindcast dataset. From the numerical simulation, it was found that motion and power production characteristics of the MPC were comparable to these of the ACL if the wave height was low enough not to activate the MPC's constraints. As the wave height increased, the two conventional control methods, excluding the MPC, couldn't keep the WEC's motion constraint. Moreover, the sea conditions in which the WEC with the MPC can operate as the power production mode was broadened compared with the two conventional control methods. Through the numerical simulations, it can be said that the WEC with the MPC is feasible in the sea condition around Japanese coast.