Thahab, Ahmed Toman
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Capacitor current analysis of a three-level neutral point clamped converter under unbalanced loading conditions Thahab, Riyadh Toman; Al-Mhana, Tahani Hamodi; Thahab, Ahmed Toman
International Journal of Electrical and Computer Engineering (IJECE) Vol 13, No 6: December 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v13i6.pp6156-6173

Abstract

A neutral point clamped (NPC) converter is considered a forefront in industrial applications. Supplying a typically balanced stand-alone load is one of those applications. However, the loading may become unbalanced which can impact the capacitors’ current and voltage ripple. In this work, an approach is proposed that analyze the capacitor current under unbalanced loading. The proposed method is based on a combination of two-dimensional Fourier series and symmetrical components. Since, two-dimensional Fourier series sectorize the spectrum into harmonics that are either defined by multiples of, fundamental, carrier or both frequencies, the method derives the Fourier coefficients for each sector, corresponding to a sequence current. Therefore, based on the presented approach, each harmonic amplitude in the spectrum sector is defined by three Fourier coefficients reflecting zero, positive and negative sequence current. The capacitor current spectrum is obtained by vector summing sequence coefficients. The method is tested on unbalanced load conditions with (out) a ground path. Results verify feasibility of the proposed method in deriving Fourier coefficients of capacitor currents that accurately reflects the loading status of the NPC. This is vital for converter design in terms of proper sizing of DC capacitor and can help in avoiding components failure.
Real-time lecture's micro-quality assessment for diabetic students based on IoTs and real-time cloud computing technologies Al-Muttairi, Alaa Imran; Abdul-Rahaim, Laith Ali; Thahab, Ahmed Toman
Bulletin of Electrical Engineering and Informatics Vol 12, No 6: December 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eei.v12i6.5641

Abstract

Students with diabetes mellitus require more academic attention, intensive flow up, and a moderate temperature environment during classes. In this paper, the learning process for those students is improved by using the internet of things (IoTs) and cloud computing technologies. The proposed system improves lecture quality using lecture micro quality which is based on lecture time segmentation. Therefore, the designed system provides each student with a microcontroller-based node to collect information about his understanding status in a real-time fashion. Based on this information, the system provides the lecturer with real-time statistical calculations about vital parameters such as the understanding status of each student, the level of the classroom's understanding ratio, and the total number of students who did not understand the topic which is being explained. The designed system is practically tested in a real classroom environment. The implemented system is practically tested in a real classroom environment and the obtained results showed up an improvement in lecture quality due to the real-time feedback which informed the lecturer to adapt the learning technique.