Influence of tidal turbine control on performance and loads

Tidal stream turbines (TST) are subject to large unsteady hydrodynamic loads which will result in fatigue of components and potentially failure. Control algorithms, if used effectively, have the ability reduce these without affecting overall performance. To examine effect control strategy on performance loads, experimental tests were carried out using a 1:15 scale TST combined wave–current facility. Loose stiff speed controllers developed implemented, addition torque control, tested for range tip-speed-ratios fixed inflow velocity. The additionally under regular, irregular focused wave conditions. Through time frequency-domain analysis, it is demonstrated that looser controllers, through larger variations, induce variations streamwise forces (rotor thrust root bending moment), but smaller torque. Similarly, extremes recorded controllers. Mean values hence turbine found be unchanged. It noted cases do not significantly affect forces; likely wave-induced velocities dominating resulting blade angles-of-attack. Additionally, some rotational significant amplification mechanical vibrations observed. These results highlight complexities associated with controller choice; considering trade-offs potential resonance, varying depending flow Proper appreciation considerations vital as we move towards commercial arrays devices must controlled optimally maximise whilst minimising loading O&M costs.