Floating wind farms (FOWF) are one of the main forms of wind energy utilization in the deep-sea areas. This study proposes a multi-objective reposition control approach for floating wind farms. Firstly, an imperial wake model of floating wind turbines is constructed considering the effects of wind and wave conditions. A nonlinear model of a catenary mooring line is subsequently constructed. Furthermore, a multi-objective location optimization method is proposed that allows for the tradeoff between the maximum power of the farm and the minimum drift distance of the turbines accounting for the time-varying wind speed and direction. The results of the proposed approach are then compared with those of traditional methods. The findings indicate that time-varying changes in wind have a significant influence on the optimal position of turbines. It can decrease the maximum drift distance by approximately 7 % when considering temporal variations in wind. Furthermore, the proposed reposition control maintains almost the same power output of the wind farm while reducing the total offset distance from the equilibrium point of turbines by approximately 11 %. The impact of mooring orientation, natural length, turbine spacing, and wave speed on the control performance are also elucidated.

Power prediction is a fundamental research topic in wind industry. Offshore wind power prediction mostly relies on either data-driven or physics-based approaches. Few approaches combine physical knowledge and operational data. Nevertheless, there is significant potential for complementarity between these two approaches. In this study, a physics-based Gaussian wake model for wind farms is first constructed, and parameters of the empirical wake model are optimally identified by Particle Swarm Optimization algorithm based on the actual operational data. A purely data-driven power prediction method is constructed through K-means clustering and parallel weighting Long Short-Term Memory with empirical mode decomposition. Based on these methods, an innovative fusion approach combining the physics-based wake model with the data-driven method is constructed using symbolic regression. Taking the real measured data from an offshore wind farm in Jiangsu, China, as a case study, the results show that the accuracy of the proposed approach is 21.67 % higher than that of the data-driven approach and 35.17 % higher than that of the physics-based approach. These results confirm the superiority of the physics-data fusion approach for wind farm power prediction.