Modelling, control and frequency domain analysis of a tidal current conversion system with onshore converters

Abstract

I would like to thank my supervisor Dr. Jonathan Shek for his close supervision, informative discussions, understanding of the problems I faced and advice throughout my PhD research. Also, I would like to thank my second supervisor, Markus Mueller, for the opportunity and the support to study and carry out research at the University of Edinburgh. His guidance and support at the initial, and at the same time difficult, stages of the PhD were crucial for the progress of the research. In addition, I would like to thank Andritz Hydro Hammerfest for the financial support as well as the information, data and advice received regarding my research. My research was also financially supported by the Institute for Energy Systems of the University of Edinburgh. Finally, I would like to thank all my friends and colleagues for the discussions we had, the different perspectives they gave me to approach problems and most importantly by making my everyday life during the last four years enjoyable.

Modelling and simulation of tidal energy generation system: a systematic literature review

“…It is very important to mention that a continuous submarine operation needs the tidal system to work reliably with the high availability of tides because various locations of tidal currents can offer a huge amount of energy density which might lead to very high power. This implies that the strategic reduction of site visits is brought to a low, as tidal devices are often mounted in places with powerful tidal currents with high flow speeds [8]. Also, another advantage of tidal generation is that it is linked to tidal networks which present energy transport in close proximity to shore and offshore substations and huge voltage hence, submarine transport will not be necessary.…”

“…It is therefore proposed that tidal power developers can be utilized to widen the accessibility of their systems by transferring the power electronics from the nacelle (hub, rotor, gearbox, generator, inverters, hydraulics, and bearings) to the shore. This will also limit site visitations since the frequency of power converter failures may be higher depending on the data gotten from the onshore wind turbines [8]. Hence, the tides speeds variations of tides sources are causing problems for the current power grid.…”

An Active FTC Strategy Using Generalized Proportional Integral Observers Applied to Five-Phase PMSG based Tidal Current Energy Conversion Systems

“…Tidal current energy has predominant advantages relative to other types of renewable energies, such as predictability, high power density, and energy continuity at almost all times, which significantly facilitates controller designs and grid connection [1]. Nevertheless, the power generation equipment, the so called tidal current turbine, is always vulnerable to harsh marine conditions that pose daunting challenges for maintenance [2]. As a result, the exploration of advanced solutions with high fault tolerance has become a main objective to practitioners and theoreticians.…”

Assessment of pulsating torque mitigation control strategy through tidal turbine emulation

“…According to [7, 8], the frequency converter, the blades and the pitch system are among the components in a renewable energy system that have both high failure rates and longer downtime for repair. Assuming that horizontal‐axis tidal current systems will have similar reliability data to wind turbine systems, the frequency converter problem was addressed in [9] by using onshore converters connected to the generator through long subsea cables. The fatigue torque mitigation (FTM) control strategy using the speed controller was first presented in [2] together with an ultimate torque reduction method for peak load reduction.…”