Abstract: In order to improve the energy capture efficiency of the wave energy converter,an optimal control scheme is proposed,which based on the double self-tuning second-order integrator（DSSOGI）frequency-locked loop and improved whale algorithm. Seeking the optimal load of the wave power system through the frequency domain response analysis of the hydrodynamic model,introducing the DSSOGI frequency-locked loop structure to measure the wave frequency in real time,the extended Kalman filter is used to estimate the wave main frequency,which can accelerate the dynamic response performance of structural frequency tracking of the frequency-locked loop. When the wave period changes,the wave frequency,the corresponding float speed and displacement after filtering is measured online by the above composite structure. The nonlinear hydrodynamic parameters are determined by using boundary element method software. Combining the improved whale optimization algorithm to find the optimal load of the system and controlling the linear power generation device,the capture efficiency is improved. The simulation results show that the proposed control scheme effectively improves the nonlinear problem of hydrodynamic parameters and increases the system output power.