https://www.um.edu.mt/library/oar/handle/123456789/16863 2026-04-28T21:15:11Z https://www.um.edu.mt/library/oar/handle/123456789/145725 Title: Residential battery storage technologies : comparative review of lithium-ion chemistries, sodium-ion alternatives, and integration with photovoltaic systems Authors: Mahrouch, Assia; Caruana, Cedric; Raute, Reiko Abstract: The adoption of Residential Battery Energy Storage Systems combined with Photovoltaic technologies is increasing as households pursue energy independence, cost reduction, and improved grid resilience. This paper provides a comparative review of Lithium-ion and Sodium-ion batteries in residential Photovoltaic applications, focusing on electrochemical performance, degradation behavior, safety, and system integration. While Lithium-ion batteries are commonly used because of their high energy density and established supply chain, whereas sodium-ion batteries are attracting interest as a safer and more cost-effective option, particularly suited for operation in moderate temperature environments. The paper also examines system-level considerations, including inverter configurations, charge/discharge control, and safety mechanisms. Special attention is given to Emergency Power Supply functionality, which enables backup power during grid outages through intelligent system coordination. Standards and certification frameworks relevant to battery deployment are reviewed, highlighting regulatory challenges. The paper concludes by discussing future research in battery chemistry, system design, and policy support, highlighting the need for scalable, safe, and effective home-based energy storage systems. 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/145724 Title: Performance testing of the hybrid inverter drive in a practical application Authors: Raute, Reiko; Caruana, Cedric Abstract: Recently, the Hybrid Inverter Drive (HID) has been developed that automatically goes into to bypass operation when the motor is operating at the grid frequency. The grid voltage synchronization algorithm facilitates a seamless switchover between inverter and direct grid-connected bypass mode without impacting the running motor operation. This technology targets to increase the energy efficiency of electric drive systems applications that require to use variable speed operation at certain times, but also operate at grid frequency for considerable durations. This paper presents the results of the HID operating in a real application. The paper shows the anticipated energy savings of the considered application and use of the HID. Additionally, it illustrates that employing the HID not only conserves electrical energy but also reduces grid current harmonic distortion, thereby enhancing grid power quality. 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/145723 Title: Instantaneous temperature estimation during short time overload operation of an IGBT Authors: Xuereb, Justin; Raute, Reiko; Micallef, Alexander Abstract: In certain applications, such as motor soft starters, power electronic devices are required to operate only for brief durations. In low-cost product designs, the smallest component sizes are selected and temporarily overloaded during short intervals to minimize component costs and sizes. This paper delves into the current overload performance of an IGBT over a 2-second period. While the temperature of the die rises rapidly, the case temperature increase is delayed due to its thermal impedance, avoiding the possibility of a direct die temperature measurement from the case. This study utilizes the emitter PN junction of the IGBT for detecting the die temperature. The paper will provide a summary of the laboratory setup and experimental results to validate the testing methodology. 2025-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/145721 Title: Permanent magnet motor systems and methods Abstract: The present disclosure, in some embodiments, thereof relates to a motor system including a permanent magnet rotor and, more particularly, but not exclusively, to a system where the stator is configured to receive multiphase electrical power from either an inverter or an electrical grid. 2025-01-01T00:00:00Z