Analytical Research of Buoy Motion and Power Response of the Floating-Type Double-Hinged Wave Energy Converter

The floating-type double-hinged wave energy converter (WEC) is developed to realize the conversion of wave energy. Based on the linear wave theory and wave-body coupled interaction, the nonlinear coupled equations of the heaving-pitching motions for the buoys are established. Under the condition of entirely linear PTO (power take-off system), the analytical solutions of pitching angles are deduced. Then the amplitude-frequency response characteristics of pitching motion and transfer power are discussed. When the collision chocks are installed in the hydraulic PTO, the time-domain changing laws of pitching angles and angular velocity are calculated by using numerical methods. The results show that the coupling effects are significant for the heaving-pitching motion. With the realistic hydraulic PTO, the average transfer power is about 11.5% lower than that of entirely linear PTO, and pitching motions of buoys show the complex periodic characteristics with wave period.