An Output Power Interval Control Strategy Based on Pseudo-Tip-Speed Ratio and Adaptive Genetic Algorithm for Variable-Pitch Tidal Stream Turbine

Abstract

Power extraction has become a critical consideration in tidal stream turbine (TST) systems. In practice, the lumped disturbances under varying tidal current conditions may deteriorate the maximum power point tracking (MPPT) performance and cumulate fatigue damage over-rated power. Besides, the conventional pitch controllers are sensitive to parameter uncertainties of the nonlinear TST system. In this paper, a novel output power internal control strategy based on pseudo-tip-speed ratio and adaptive genetic algorithm (PTSR-AGA) is proposed to improve the anti-interference ability and reliability. The proposed control scheme consists of two parts. The first part proposes the PTSR method for MPPT to predict the TST’s operating point which contributes reducing the logical errors assigned to swell disturbances. The second part designed an AGA for the optimization of the pitch controller to conduct its angle delay. A reduced pitch control strategy is applied to the preprocessing of the pitch controller to reduce the mechanical wear over the rated power. The comparative simulation results validate the TST system can obtain a higher power efficiency of energy capture and a smoother power output with the proposed control strategies at full range of tidal current speed.

Fault-Tolerant Control of Tidal Stream Turbines: Non-Singular Fast Terminal Sliding Mode and Adaptive Robust Method

“…The proposed ANFTSMC method is evaluated below the rated tidal current speed and the results are compared with fuzzy adaptative backstepping control (FABC) , active disturbance rejection control (ADRC) [1], integral sliding mode control (ISMC) [56], and non-singular fast terminal sliding mode control (NFTSMC) [22]. Then, a comparison of variable pitch control methods, including gain scheduling proportional integral derivative (GSPID) [57], ISMC, and pseudo-tip-speed ratio and adaptive genetic algorithm (PTSRAGA) [58], are considered. The effectiveness of the proposed ANFTSMC-ARC method above the rated tidal velocity was evaluated by comparing the ANFTSMC-ARC method with the FABC-GSPID, ISMC-ISMC, and ADRC-PTSRAGA methods by combining MPPT with pitch control.…”