Design and analysis of a bidirectional rack and pinion Wave Energy Converter (WEC)

Ocean wave energy is becoming very popular among all the current renewable energy sources because of its cleanliness, availability, high power density and pollution free nature. Many wave energy converters have been designed and analyzed with various power take off systems like air turbines, hydroelectric components, and slider crank. In this thesis, the easiest and most effective method of using rack and pinion type power take off system, is discussed and the performance of the whole system is analyzed. The bidirectional motion of the pinion is converted into unidirectional motion by applying ratcheting method. This increases the overall efficiency of the system. A wave energy converter containing buoy and a mechanical motion rectifier (MMR) based rack and pinion are proposed to be designed and simulated in MATLAB Simulink environment. This system mainly consists of a buoy that is semi-submerged into the water. The ocean waves exert force on the submerged buoy. The up and down movement of the buoy is then converted into unidirectional rotation by rack and pinion mechanism. Through a gear box this rotational motion drives the generator to produce electricity. The control strategy keeps the generator’s velocity and wave excitation force in resonance. Here, a time domain system analysis method is applied for solving the equation that describes the relationship between the buoy motion and hydrodynamic forces in both cases of regular wave and irregular waves. The simulation results for the regular and irregular ocean waves are presented and compared with other state-of-the-art power take off systems