Advanced Maximum Power Control Algorithm Based on a Hydraulic System for Floating Wave Energy Converters

An integrated analysis is required to evaluate the performance of control algorithms used in power take-off (PTO) systems for floating wave energy converters (FWECs). However, research on PTO systems based on the existing hydraulic device has mainly focused on the input power generation performance rather than on obtaining maximum power through hydraulic device-based electrical load control. The power generation performance is analyzed based on the control variables of the existing torque control algorithm (TCA); however, the amount of power generation for each control variable changes significantly based on the cycle of wave excitation moments. This paper proposes a control algorithm to obtain the maximum power by modeling a hydraulic-device-based integrated FWEC. It also proposes a TCA that can obtain the maximum power regardless of the period of wave excitation moment. The proposed TCA continuously monitors the power generation output and changes the PTO damping coefficient in the direction in which the power generation output can be increased. The proposed TCA increased the output power generation by up to 18% compared to each PTO damping coefficient of the conventional TCA. Thus, the proposed method results in higher power generation regardless of the wave excitation moment cycle and performs better than the existing torque control algorithm.