Investigation on PTO control of a Combined Axisymmetric Buoy-WEC(CAB-WEC)

Fankai Kong, Weiming Su, Hengxu Liu, Maurizio Collu, Zi Lin, Hailong Chen, Xiongbo Zheng

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)
8 Downloads (Pure)


The Combined Axisymmetric Buoy (CAB), a vertical axisymmetric buoy, has the potential to deliver a high energy absorption power. Considering the CAB-Wave Energy Converters (WEC), in order to achieve higher efficiency, the Power Take Off (PTO) systems, which converts the float motion into energy output, needs to be properly controlled. In this paper, a PTO control method for a CAB-WEC under irregular wave conditions is proposed. Based on the semi-analytical solution obtained in the time domain, a numerical optimization is carried out. The optimal PTO damping coefficients under different wave conditions are obtained, by considering the parameter defined as “capture width ratio”. The expression of the optimal PTO damping coefficient in the frequency domain is derived by an analytical method. Based on the semi-analytical solution of time domain dynamic characteristics and analytical method, a comparison between frequency domain optimization and time domain optimization is presented. In general, the two approaches arrive to very similar conclusions, even if with the time domain methodology a slightly higher capture width ratio is achieved. The experimental results have been used to validate the time domain optimization method and the variation in optimal average capture width ratio results.
Original languageEnglish
Article number106245
JournalOcean Engineering
Early online date8 Aug 2019
Publication statusPublished - 15 Sept 2019
Externally publishedYes


Dive into the research topics of 'Investigation on PTO control of a Combined Axisymmetric Buoy-WEC(CAB-WEC)'. Together they form a unique fingerprint.

Cite this