Browsing by Author "Ibrahim, Kingsley"

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    Design feasability of the electrical network for turboelectric aircraft propulsion.
    (2020-01) Ibrahim, Kingsley; Sampath, Suresh; Nalianda, Devaiah
    The motivation for this research is the need for safer and more environmentally friendly air transport system. Electrical propulsion systems have been identified as a potential method for improving aircraft performance going forward. The implementation of electrical drive trains for future aircraft propulsion comes with many challenges, due to the novelty and scale of the intended deployments. Major technological advancements and research are ongoing at system and component level to meet this ambition. However, the feasibility aspects of these studies have focused more on the engine side than on the electrical aspects, especially with regards to system reliability and stability. These have been considered in the earlier proposed sizing methods, using assumed fault and transient current magnitudes. Such assumption implies that the control and protection systems, may not properly handle abnormal operational scenarios. The aim of this research is to establish a procedure for sizing components of an electric propulsion system considering reliability and stability. The major objective is to properly quantify the operating parameters in non-steady state operations, like transients and fault scenarios, and establish that components are operating within their thermal limits at all operational stages. The contribution of this work is the development of a method that incorporates stability and reliability in the sizing process of electrical propulsion networks. The practicality of the proposed methods has also been validated experimentally, using a test facility set up for this study. The impact of this work is the reduction of the design uncertainties, resulting from assumed fault and transient characteristics of an electrical propulsion system. The results show that the assumptions in earlier researches do not suffice for the investigated architectures. A considerable mass penalty is incurred, with the power electronic devices having to be sized for slightly higher than the maximum transient currents.
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    Optimal voltage and current selection for turboelectric aircraft propulsion networks
    (IEEE, 2020-06-23) Ibrahim, Kingsley; Sampath, Suresh; Nalianda, Devaiah
    Deploying electrical systems for aircraft propulsion have been identified as a potential solution, for reducing the environmental impact of the increasing air transport usage. However, the implementation of this system needs to be done at a suitable voltage and current combination. The aim of this work is to propose a clear procedure, for deriving a suitable voltage and current for an electrical propulsion system, based on the aircraft dimensions and thrust requirement. The approach presented, considers feasibility and minimum mass as boundary and target respectively. The results show that the fan configuration and thrust requirement directly influence the choice of optimal voltage and current. This is due to the varied impact on device sizes and overall propulsion system performance. Major drivers of the selected voltage and current are the loading coefficient, speed and torque requirement of the fan. The knowledge of these is a requirement to arrive at an optimal voltage for the propulsion system
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    Voltage synchronisation for hybrid-electric aircraft propulsion systems
    (Cambridge University Press, 2021-07-22) Ibrahim, Kingsley; Sampath, Suresh; Nalianda, Devaiah
    Increasing demand for commercial air travel is projected to have additional environmental impact through increased emissions from fuel burn. This has necessitated the improvement of aircraft propulsion technologies and proposal of new concepts to mitigate this impact. The hybrid-electric aircraft propulsion system has been identified as a potential method to achieve this improvement. However, there are many challenges to overcome. One such challenges is the combination of electrical power sources and the best strategy to manage the power available in the propulsion system. Earlier methods reviewed did not quantify the mass and efficiency penalties incurred by each method, especially at system level. This work compares three power management approaches on the basis of feasibility, mass and efficiency. The focus is on voltage synchronisation and adaptation to the load rating. The three methods are the regulated rectification, the generator field flux variation and the buck-boost. This comparison was made using the propulsion system of the propulsive fuselage aircraft concept as the reference electrical configuration. Based on the findings, the generator field flux variation approach appeared to be the most promising, based on a balance of feasibility, mass and efficiency, for a 2.6MW system.