Performance enhancement of an impulse turbine for OWC using grouped grey wolf optimizer based controller

This work deals with unsteady analysis and control of a bi-directional impulse turbine equipped in oscillating water column (OWC) wave energy converter (WEC). The Unsteady Reynolds-averaged Navier-Stokes equations (URANS) were solved to get the turbine characteristics and the maximum efficiency tracking for different axial velocities. The grouped grey wolf optimization (GGWO) algorithm finds the optimal gains of proportional-integral-derivative (PID) controllers of a permanent magnet synchronous generator (PMSG), such that a maximum efficiency tracking can be achieved. The URANS analysis show that the best efficiency point (BEP) occurs at a flow coefficient of 1.25. The GGWO based controller increases efficiency by 61.5% and 4% compared to the uncontrolled and conventionally controlled case, respectively and limits the peak-to-average power ratio by 38.6% compared to the uncontrolled case. [Display omitted] •With URANS analysis of the turbine, BEP occurs at Φ = 1.25, due to compensation between incidence and tip leakage losses.•The GGWO algorithm is applied for the BEP tracking of an impulse turbine working under regular and irregular sea states.•Results show that GGWO works with the minimum tracking error when compared to GA, PSO, AIPSO and GWO.•The GGWO based controller maximized the efficiency by 61.5% and 4% compared to uncontrolled and typically controlled case.•The GGWO based controller limits the peak-to-average power ratio by 38.6% compared to uncontrolled case.