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. © 2019 Elsevier Ltd