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Undesired motions in Floating Offshore Wind Turbines (FOWT) lead to reduction of system efficiency, the system’s lifespan, wind and wave energy mitigation and increment of stress on the system and maintenance costs. In this article, a new barge platform structure for a FOWT has been proposed with the objective of reducing these undesired platform motions. The newly proposed barge structure aims to reduce the tower displacements and platform’s oscillations, particularly in rotational movements. This is achieved by installing Oscillating Water Columns (OWC) within the barge to oppose the oscillatory motion of the waves. Response Amplitude Operator (RAO) is used to predict the motions of the system exposed to different wave frequencies. From the RAOs analysis, the system’s performance has been evaluated for representative regular wave periods. Simulations using numerical tools show the positive impact of the added OWCs on the system’s stability. The results prove that the proposed platform presents better performance by decreasing the oscillations for the given range of wave frequencies, compared to the traditional barge platform.

In this article, a new strategy for switching control has been proposed with the aim of reducing oscillations in floating offshore wind turbines. Such oscillations lead to a shortage in the system’s efficiency, lifespan and harvesting capability of wind and wave energies. In order to study the decreasing of undesired oscillations in the system, particularly in pitch and top tower fore-aft movements, a square-shaped platform barge equipped with four symmetric oscillating water columns has been considered. The oscillating water columns’ air flux valves allow to operate the air columns so that to control the barge movements caused by oscillatory motion of the waves. In order to design the control scheme, response amplitude operators have been used to evaluate the performance of the system for a range of wave frequency profiles. These response amplitude operators analysis makes it possible to implement a switching control strategy to adequately regulate the valves opening/closing transition. The obtained results show that the proposed controlled oscillating water column-based barge present a better performance compared to the traditional barge one. In the case study with the period of 10 s, the results indicate the significant oscillation reduction for the controlled oscillating water column-based system compared to the standard barge system by 30.8% in pitch angle and 25% in fore-aft displacement.

The implementation and integration of new methods and control techniques to floating offshore wind turbines (FOWTs) have the potential to significantly improve its structural response. This paper discusses the idea of integrating oscillating water columns (OWCs) into the barge platform of the FOWT to transform it into a multi-purpose platform for harnessing both wind and wave energies. Moreover, the OWCs will be operated in order to help stabilize the FOWT platform by means of an airflow control strategy used to reduce the platform pitch and tower top fore-aft displacement. This objective is achieved by a proposed complementary airflow control strategy to control the valves within the OWCs. The comparative study between a standard FOWT and the proposed OWC-based FOWT shows an improvement in the platform’s stability.