DC Microgrids for offshore applications
R&D Focus Areas:
Electricity, Energy systems integration
Lead Organisation:
Griffith University
Partners:
University of Tasmania, Optimal Group Australia, pitt&sherry
Status:
Completed
Start date:
September 2020
Completion date:
June 2024
Key contacts:
Professor Evan Gray; e.gray@griffith.edu.au
Funding:
Blue Economy CRC
Project summary description:
Photovoltaics, batteries, supercapacitors, electrolysers and fuel cells are all natively DC. DC power is common in marine settings. Networking these components into a microgrid using high-efficiency DC–DC converters is logical, but problematic in practice, and few suitable DC–DC converters are available commercially. Most microgrids are presently AC coupled with grid connection, therefore, involving multiple AC-DC conversions and issues of frequency synchronisation and voltage stabilisation.
This project addressed the barriers to setting up pure-DC microgrids and created a pure-DC hydrogen microgrid at 10 kW scale for experiments aiming to understand and resolve issues including transient response and control of the DC bus voltage. The microgrid includes physical batteries (22.5 kWh Li-ion), programmable emulators for PV, wind and wave generators, which can be driven by data sampled for a selected geographic location. A programmable source and load emulate a hydrogen fuel cell and an electrolyser, with hydrogen storage simulated in software. A programmable electronic load allows load profiles for many situations to be applied, based on real load data. The generators, battery and loads are connected to the DC bus with off-the-shelf DC/DC converters.
The microgrid is operational, based on simple linear droop controls that employ the battery, electrolyser and fuel cell to maintain the DC bus voltage in a specified range in the face of varying supply of renewable energies and varying demand.
Related publications and key links:
Waqas Hassan et al., Stability Assessment of Renewable Energy-Based DC Microgrids for Offshore Applications, 4th International Conference on Smart Power & Internet Energy Systems (SPIES) (2022), DOI: 10.1109/SPIES55999.2022.10081994
Alamgir Hossain et al., Small-signal Stability Analysis of Offshore DC Microgrids, IEEE International Conference on Energy Technologies for Future Grids (ETFG) (2023), DOI: 10.1109/ETFG55873.2023.10407730.
Alamgir Hossain et al., Comparative Study of Different Controllers for Offshore DC Microgrids, IEEE Fifth International Conference on DC Microgrids (ICDCM) (2023), DOI: 10.1109/ICDCM54452.2023.10433595.
Higher degree studies supported:
One PhD student at Griffith University and one at University of Tasmania.
Reviewed: August 2024