Consideration on how to decide the optimal control force of a PA-WEC for maximizing its electric power generation in irregular waves

This paper describes an analytical solution on the optimal control force for maximizing power generation of Point Absorber Wave Energy Converter (PA-WEC) in irregular waves. The response and optimum control force on a PA-WEC in regular waves achiving a maximum electric power generation has been already developed taking into account the energy loss in the electric circuit in frequency domain and in regular waves. On the other hand, in irregular waves, to obtain the best control force in timely has been difficult, because the control force act on the instantaneous power generation rate and the whole later heaving response of the PA-WEC. This means that whether the decided control force is the best or not is difficult to judge. Actually, in the previous researches, the researchers applied a lot of way to decide the control force. But the generated electric power in irregular waves ratio to the expected generated power obtained from the wave spectrum is up to almost from 0.3 to 0.7. This paper presents an analytical solution of the control force parameter for maximizing the generated electric power in irregular waves on a PA-WEC in time domain. Then, numerical studies are carried based on the proposed method. From these results, it is shown that the proposed method achieves the generated electric power to the expected generated power obtained from the wave spectrum