Control of an open-loop hydraulic offshore wind turbine using a variable-area orifice

• Published in: Volume 9: Ocean Renewable Energy
• Main Authors: Buhagiar, Daniel, Sant, Tonio, Bugeja, Marvin K., 34th International Conference on Ocean, Offshore and Arctic Engineering
• Format: Conference Object
• Language: English
• Published: American Society of Mechanical Engineers (ASME) 2015
• Subjects: Wind turbines; Electric generators; Nozzles; Hydraulic engineering > Equipment and supplies; Nozzle; The Nozzle; Arctic
• Online Access: https://www.um.edu.mt/library/oar//handle/123456789/18792; https://doi.org/10.1115/OMAE2015-41388

The research work disclosed in this publication is partly funded by the Malta Government Scholarship Scheme. The viability of offshore wind turbines is presently affected by a number of technical issues pertaining to the gearbox and power electronic components. Current work is considering the possibility of replacing the generator, gearbox and electrical transmission with a hydraulic system. Efficiency of the hydraulic transmission is around 90% for the selected geometries, which is comparable to the 94% expected for conventional wind turbines. A rotor-driven pump pressurises seawater that is transmitted across a large pipeline to a centralised generator platform. Hydroelectric energy conversion takes place in Pelton turbine. However, unlike conventional hydro-energy plants, the head available at the nozzle entry is highly unsteady. Adequate active control at the nozzle is therefore crucial in maintaining a fixed line pressure and an optimum Pelton turbine operation at synchronous speed. This paper presents a novel control scheme that is based on the combination of proportional feedback control and feed forward compensation on a variable area nozzle. Transient domain simulation results are presented for a Pelton wheel supplied by sea water from an offshore wind turbine-driven pump across a 10 km pipeline. peer-reviewed