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Cerimagic, Remzija


PROJECT TITLE:Development and Optimization of Mechanical Topology for Digital Displacement Units      

PhD period: 2015.09.01 - 2018.08.31. (has been prolonged till 2019.08.31)
Section: Fluid Power and Mechatronic Systems
Research Programme: Fluid Power in Wind and Wave Energy 
Supervisor: Torben Ole Andersen
Co-Supervisor: Per Johansen
Contact information

Collaborators: Institute of Machine Design and Hydraulic Drives, Johannes Kepler Universität (JKU), Austria, Austrian Center of Competence in Mechatronics (ACCM), Austria, Bosch Rexroth A/S (BR), Denmark/Germany, Vestas Wind Systems A/S (VWS), Denmark and Wave Star A/S (WS), Denmark.
Funding: DSF Grant.


Typically, the power transmission in wind turbines is carried out by a mechanical gearbox connected to an electric generator, which again is connected to the electric grid. The size of the wind turbines are increasing steadily due to technological advancement within the field. When using a mechanical gearbox to transfer the power, friction and wear occurs in the gear box. Due to the still increasing size of wind turbines the mechanical gearbox topology is pushed to the limit by the increasing demands in reliability, efficiency and power density.

Due to recent technological advancements in fluid power it is expected that fluid power based transmission topologies soon constitutes a competitive alternative to the classic wind turbine configuration with the mechanical gearbox. It is envisioned that the power ranges of wind turbines may be stretch additionally by use fluid power based transmission topologies. The fluid power transmission is based on the digital displacement technology (DDT). As a consequence of using DDT the mechanical gearbox is eliminated along with the power electronic converter.

The major objective of the research project is to investigate the digital displacement technology and its use for high-power hydrostatic transmission in both wind turbines and in wave energy converters. The displacement is to be varied by enabling or disabling individual pressure chambers. The flow in and out of the individual pressure chambers are to be controlled by electrically actuated fast switching valves. This PhD-project deals with one of five work packages, which are to be carried out in the research project. This work package deals with development of digital displacement units where design, analysis and optimization of efficiency and reliability of tribological interfaces in the digital displacement units are in focus.


Publications in journals and conference papers may be found at VBN.