Abstract: In order to reduce the influence of wave non-smooth characteristics on the energy absorption of direct-drive wave power system,the ridge detection and variational nonlinear chirp mode decomposition is proposed as the control scheme. Using the short-time Fourier transform method to analyze the wave excitation force,the initial frequency is set combined with the ridge detection;using the variational nonlinear chirp mode decomposition method to separate the wave excitation force,obtain several mode components and extract their instantaneous frequencies. Through calculating the energy content of each mode component to determine the dominant component,the damping of the power output device is dynamically adjusted according to its instantaneous frequency to build a model of the direct-drive wave power generation system. Results of the simulation demonstrate that this proposal provides better energy absorption capability and more average power output,thus effectively increasing the power absorption performance of the direct-drive wave power system.