Electrical and Electronic Engineering Research Collection
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- PublicationInclusive Teaching & Learning Case Studies in Engineering, Architecture & Affiliated Disciplines(UCD Access & Lifelong Learning, 2021-10-14)Diversity and inclusion are core to UCD values. We seek to attract students from a wide range of social and economic backgrounds and students who reflect the true diversity of the country. And as a global university, UCD attracts international students from over 100 countries. This diversity enriches our campus, and the experience of our students. The University's strategy 2020-2024 'Rising to the Future' also recognises the importance of inclusion and diversity, in seeking to "provide an inclusive educational experience that defines international best practice and prepares our graduates to thrive in present and future societies." However, an inclusive educational experience will not be achieved by simply creating diversity in the student body. It requires that we adjust our approach in everything we do to support and encourage our students’ success. We have clearly articulated in our strategy, and further emphasised in our Education and Student Success strategy, that our goal is to "equip all our educators with the tools and resources required to embed Universal Design for Learning on an institution-wide basis".
33 - PublicationXGboost-based Method for Seizure Detection in Mouse Models of Epilepsy(IEEE, 2020-12-05)Epilepsy is a chronic neurological disease which affects over 50 million people worldwide [1], caused by the disruption of the finely tuned inhibitory and excitatory balance in brain networks, manifesting clinically as seizures. Electroencephalographic (EEG) monitoring in rodent disease models of epilepsy is critical in the understanding of disease mechanisms and the development of anti-seizure drugs. However, the visual annotation of EEG traces is time-consuming, and is complicated by different models and seizure types. Automated annotation systems can help to solve these problems by reducing expert annotation time and increasing the throughput and reliability of seizure quantification. As machine learning is becoming increasingly popular for modelling sequential signals such as EEG, several researchers have tried machine learning to detect seizures in EEG traces from mouse models of epilepsy. Most existing work [2], [3] can only detect seizures in single mouse models of epilepsy and research on multiple mouse models has been limited to-date.
15 - PublicationAutomated Filter Selection for Suppression of Gibbs Ringing Artefacts in MRI(Elsevier, 2022-11)Gibbs ringing creates artefacts in magnetic resonance images that can mislead clinicians. Reconstruction algorithms attempt to suppress Gibbs ringing, or an additional ringing suppression algorithm may be applied post reconstruction. Novel reconstruction algorithms are often compared with filtered Fourier reconstruction, but the choices of filters and filter parameters can be arbitrary and sub-optimal. Evaluation of different reconstruction and post-processing algorithms is difficult to automate or subjective: many metrics have been used in the literature. In this paper, we evaluate twelve of those metrics and demonstrate that none of them are fit for purpose. We propose a novel metric and demonstrate its efficacy in 1D and 2D simulations. We use our new metric to optimise and compare 17 smoothing filters for suppression of Gibbs artefacts. We examine the transfer functions of the optimised filters, with counter-intuitive results regarding the highest-performing filters. Our results will simplify and improve the comparison of novel MRI reconstruction and post-processing algorithms, and lead to the automation of ringing suppression in MRI. They also apply more generally to other applications in which data is captured in the Fourier domain.
9 - PublicationGrid-Forming Dynamic Stability under Large Fault Events – Application to 100% Inverter-based Irish Power System(Taylor & Francis, 2022)System stability is investigated for a future Irish grid consisting entirely of GFMIs under three-phase fault conditions with the inverters placed at existing locations for large-scale conventional generation. Electromagnetic transient (EMT) simulations showed that a 100% GFMI system, employing either droop control (or virtual synchronous machine), dispatchable virtual oscillator control, or a mix of both, under a combination of virtual impedance (VI) and scaling current saturation limiting control, is robust against 3-phase faults, with consistent performance being achieved, despite variations in fault location or inverter control methods. Freezing GFMIs virtual angular speed during the fault, for both VI and current scaling approaches, system transient stability is greatly enhanced. Time domain simulations also show that when active or reactive current prioritisation current saturation controls are applied that GFMIs can introduce large, high-frequency resonance oscillations, but a scaling-down current saturation approach can help to mitigate such problems by generating smoother current references.
103 - PublicationVoltage Dip Induced Frequency Dips for Power Systems with High Shares of Wind Energy(IEEE, 2022-06-29)In order to limit drivetrain mechanical stress, wind turbine generators typically implement a delayed active power recovery following a voltage dip, which may result in a substantial reduction in system frequency, if many wind farms adopt a similar strategy, due to the resulting generation-demand imbalance. Therefore, based on a modified IEEE 39-bus system, the impact of active and reactive current priority strategies, and various reactive current loop controls for wind turbine generators on voltage dip induced frequency dips (VDIFDs) are examined. The effectiveness of local voltage control with reactive current priority is validated. In addition, if synchronous-based generation is displaced by grid-forming converters (GFMs), the frequency dips are less severe and the post-fault frequency recovers more quickly. However, due to reduced overcurrent capability, the GFM virtual angle control must be carefully designed to avoid transient instability, by, for example, reducing the droop gain. Finally, if DC-link voltage control and maximum power point tracking control for the grid-side and machine-side converters are switched (to simplify fault ride through implementation) care is needed to avoid large post-fault over-frequency transients for VDIFD events.
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