Wave Excitation Force Estimator Using Kalman Filtering Approach for Point Absorber Wave Energy Converters Under Different Modeling and Operation Scenarios

Abstract

In this research, one of the most important research questions that influence the effectiveness of the used control strategies in heaving wave energy converters (WECs) is addressed. A nonlinear extended Kalman filter (EKF) based state estimator to estimate the wave excitation force and heave velocity in real-time is proposed. A holistic nonlinear model involving both the mechanical and electrical sides of the WEC system is used. The proposed estimator was compared with a simpler linear Kalman filter (KF) estimator under varying sea state environment and electric loading conditions. Generally, both estimators produced "statistically" good estimates, however, the EKF estimators outperformed its counterpart in both the estimation accuracy and maintaining low incident energy drop.