/library/oar/handle/123456789/5677 2025-12-29T13:54:16Z 2025-12-29T13:54:16Z /library/oar/handle/123456789/127800 2024-10-24T08:26:55Z 2024-01-01T00:00:00Z

Title: Improved EPS functionality for AC-coupled battery storage systems Abstract: With the growing demand for installations of renewable energy systems (RES), the integration of photovoltaic (PV) systems with energy storage systems (ESS) has become essential for maintaining grid stability and ensuring reliable power supply. This project addresses a critical limitation in AC-coupled ESS configurations, which traditionally do not allow PV generation during grid failures, thereby relying solely on stored battery energy. This project proposes a solution that introduces a controller to enable PV generation in emergency power supply (EPS) mode, enhancing system resilience and efficiency. The research begins with a comprehensive analysis of AC and DC coupling ESS configurations, highlighting the advantages and limitations of each. A software simulation was developed to compare the already established frequency shifting method with the proposed controller-based solution. The controller, designed and implemented as part of this project, enables communication between the PV inverter and battery inverter as well as controlling the PV inverter maximum power generation. This ensures seamless PV generation during grid outages. Practical tests confirmed that the new system configuration significantly improves power capability and stability in EPS mode. The controller not only allows for the use of PV inverters with higher power capacities than battery inverters but also supports retrofit applications, making it a versatile solution for various installations. Additionally, the project explored future enhancements, including improved communication protocols and expanded functionality to support demand response operations. This innovative approach offers a robust solution to enhance the functionality and reliability of residential and commercial AC-coupled ESS, paving the way for more resilient and sustainable energy systems. Description: B.Eng. (Hons)(Melit.)

2024-01-01T00:00:00Z /library/oar/handle/123456789/127798 2024-10-24T08:26:07Z 2024-01-01T00:00:00Z

Title: The design and building of sodium-ion battery for home energy storage Abstract: This thesis focuses on the design and construction of home energy storage systems using sodium-ion battery technology. As global emphasis shifts towards sustainable energy solutions and the integration of renewable energy sources, the demand for efficient and reliable energy storage has escalated. Sodium-ion batteries, recognized for their affordability and favourable electrochemical properties, present a viable alternative to traditional lithium-ion systems due to the abundance and cost-effectiveness of sodium. As well as its superior performance especially in terms of safety. This research explores various aspects of sodium-ion technology, including battery design, system integration, and performance evaluation within home energy settings. The objectives include a comprehensive literature review of existing energy storage technologies, a detailed examination of sodium-ion battery properties, and the development of a home energy storage system prototype. The methodology involves designing the battery architecture and integrating it with existing home systems, followed by extensive testing to assess performance, reliability, and scalability. The findings aim to contribute to the advancement of sustainable energy technologies by providing insights into the application of sodium-ion batteries in home energy storage, aligning with global efforts in climate change mitigation and energy sustainability. Description: B.Eng. (Hons)(Melit.)

2024-01-01T00:00:00Z /library/oar/handle/123456789/127797 2024-10-24T08:25:21Z 2024-01-01T00:00:00Z

Title: Integration of battery energy storage in the Maltese LV network Abstract: Historically, electricity distribution relied solely on centralized sources with no integration of alternative energy sources. However, the surge in renewable energy adoption, particularly from wind and solar, demands innovative solutions to uphold network reliability and efficiency. This dissertation delves into the integration of battery energy storage systems (BESSs) into low voltage networks to navigate these evolving challenges. The objectives of this study encompass a comprehensive understanding of energy storage concepts, simulations of feeder systems with integrated energy storage, placement, and capacity sizing of BESS units. Moreover, it aims to provide an analysis of diverse discharge modes and assess the impact on network power flow dynamics. The findings highlight the effectiveness of peak shaving support in providing support over load following mode. This results in improved power quality and voltage stability along the feeder, while continually maintaining optimal discharge levels to prevent degradation of the BESS. Moreover, selecting battery technologies tailored for peak shaving, offer compelling advantages over those optimized for load following, primarily due to reduced operating flexibility requirements. Furthermore, the integration of BESSs results in a comprehensive enhancement in network performance, curbing energy wastage and maximizing solar energy utilization, thereby fostering sustainability and elevating power quality standards within the feeder infrastructure. Description: B.Eng. (Hons)(Melit.)

2024-01-01T00:00:00Z /library/oar/handle/123456789/127796 2024-10-24T08:18:57Z 2024-01-01T00:00:00Z

Title: A solid-state smart transformer Abstract: The Smart Transformer (ST) is a transformer built around power electronic converters (PEC). Due to its improved controllability, besides performing the fundamental task of stepping up and down line frequency voltages, the ST can provide a number on ancillary services to satisfy the evolving needs of the grid. The ST can improve integration of distributed generation (DG) and renewable energy sources (RES) to reduce carbon emissions. Additionally, power quality at both transmission and distribution levels can be improved. This dissertation revolves around the control of a LV/LV Back-to-Back (B2B) inverter in SIMULINK®, using PLECS®. The first section of the dissertation is a review of existing literature on the topic, followed by the design and implementation of the converter in the SIMULINK® model. This involves design of the LCL filters to attenuate harmonic emissions from the converter and design of the relevant current and voltage control loops. Finally, a number of case studies based on load current and line voltage profiles measured on a LV feeder were performed to assess the line and load regulation of the designed converter. From the case studies it was determined that the ST has excellent performance in both line and load regulation. When the load power was varied, the converter was able to maintain a nominal voltage of 230VRMS during steady-state operation. The transient performance of the ST lead to momentary over and under voltages when subjected to sudden load power changes. However, due to the design of the control, these lasted no more than 0.3s. In the line regulation case studies, one can observe that the ST, unlike a conventional power transformer (CPT), is able to completely decouple the power network feeding the transformer from the load being fed by it. Although the RMS grid voltage was varied, the load voltage remained unchanged. This proves the decoupling effect that a ST can have, due to the presence of a DC link. The results show that a ST is able to greatly improve power quality. Due to the potential of the ST concept, more research into the field is warranted to explore the full capability of such a device. Description: B.Eng. (Hons)(Melit.)

2024-01-01T00:00:00Z