From Springer Nature via Jisc Publications RouterHistory: received 2020-12-06, registration 2021-04-16, accepted 2021-04-16, pub-print 2021-05, pub-electronic 2021-05-10, online 2021-05-10Publication status: PublishedFunder: H2020 European Research Council (); Grant(s): Marinet2 Project M4WW (no 1179)Abstract: It is desirable to control pitch motion of semi-submersible wind platforms to reduce turbine hub acceleration and increase structural fatigue life. This is achieved by balancing the moment on the platform due to heave float excitation by generating a differential internal head of water between the floats though a pump. This is demonstrated with an experimentally validated linear diffraction-radiation-drag model of an idealised platform. Different scales of platform are considered corresponding to 5, 10 and 20 MW turbines. The pitch angles and hub accelerations generally reduce as scales increase. Pumping reduces hub accelerations by up to about 40% for larger sea states. The power required for pumping would be small with a hybrid pump also operating as a turbine to store energy for the pumping operation. Without storage the power requirement is still small relative to the turbine capacity except for very high wind speeds
