Project

To transfer energy from collected offshore wind farms over a long distance, HVDC transmission is preferred over HVAC in terms of efficiency and economy. Several multi-stage configurations have been proposed in the literature. However, the multi-stage configuration generally results in a large size due to a large number of conversion stages, relatively high cost, and low efficiency and power density. Also, the independent control of several converters and communication among the sources make the system complex. To overcome these disadvantages, multi-port modular DC/DC topologies have been suggested. Multiport converters are highly non-linear MIMO systems with many control variables. Also, the coupling between the control variables makes modeling and control system design complicated. Despite such complexity, advanced control techniques have not been comprehensively studied. Moreover, most controller design work on multiport converters has not considered the uncertainties of the converter model. In this Ph.D. study, a robust controller is implemented for multi-port modular DC/DC converter for offshore wind farms application.

HVDC offshore wind farms with MVDC power collection have recently aroused researchers' interest as these systems offer lower losses and fabrication expenses. Numerous potential MVDC converters could be used in the power collection stage of offshore wind farms; however, when it comes to the technology level, these DC/DC converters are still immature since no substantial studies concerning their control exist. Thus, this Ph.D. project aims to address the research gap to enhance the performance as well as the efficiency of an MVDC converter. The novel switching and control technique proposed in this project together with the significant features of wide bandgap switches provide the condition based on which the MVDC converter could operate at higher switching frequencies than what is already possible. Hence, the controlled MVDC converter will be smaller in size and lighter in weight compared to the conventional ones which reduces the LCOE and provides better possibilities for modularity.

Turkey is one of the fastest-growing energy markets in the world, with an annual 8% increase in energy demand. By the end of 2018, the total installed capacity and electricity production of Turkey was 88.5 GW and 300.7 TWh, respectively. Nowadays, more than 70% of all electricity production is supplied by fossil resources, and almost 30% of all electricity production comes from renewables, mainly hydro, while wind constitutes only 6.6% of the total electricity mix.

The wind and solar energy rate in total consumption are planned to be increased by at least 30% in the coming five years according to the 2023 vision plan of Turkey. However, due to the intermittent nature of wind energy, large-scale wind power integration may pose some serious challenges to Turkey's power system. Therefore, planning analysis and designing efforts are required to ensure the smooth, secure and reliable operation of Turkey's power system and electricity markets considering large-scale wind power integration. WindFlag aims to solve relevant challenges of large scale OWPP deployment and integration into the Turkish grid, such as extreme weak-grid situations, islanding conditions, and large harmonics and resonances.

An CETPartnership project with the aim to enhance shared mooring system design for floating offshore wind farms.