The working principle of the proposed topologies are theoretically demonstrated, numerically verified, and experimentally validated through an in-house experimental setup.
Ahmed Mohamed Salem Ali
Ph.d.-kandidat
Ahmed Mohamed Salem Ali fra Fakultet for teknologi og realfag ved UiA disputerer for ph.d.-graden med avhandlingen «Multilevel Inverters with Reduced Component Count for Energy Systems» mandag 18. oktober 2021.
Han har fulgt doktorgradsprogrammet ved Fakultet for teknologi og realfag ved UiA, med spesialisering i ingeniørvitenskap, vitenskapelig område fornybar energi.
Multilevel inverters (MLIs) have gained increasing interest for advanced energy-conversion systems with a wide range of voltage levels, due to their attractive features of low harmonic contents, low dv/dt stress, low filtering requirements, low switching frequency, low electromagnetic interference (EMI), and employing low-rated semiconductor devices for producing high voltages.
Further, some MLIs have a modularity feature, facilitating voltage and current scalability with high redundancy in switching states, allowing for fault-tolerant operations.
The mentioned features are directly related to the number of generated voltage levels.
However, enlarging level count renders challenges of requiring massive component counts, including DC sources, capacitors, power diodes, switches, inductors, and transformers.
The high count of components negatively affects the size, cost, efficiency, lifespan, reliability, complexity of MLI-based energy conversion systems.
Thus, proposing novel MLIs, which can enlarge the voltage level number with a low component count, is currently one of the most attractive topics in this research theme.
In this dissertation, four three-phase topologies are proposed to mitigate the aforementioned shortcomings.
Two transformerless topologies are proposed for low- and medium voltage applications, while two transformer-based topologies are intended for medium- and high-voltage applications.
The proposed topologies have the key features of being capacitor-, diode-free, and low counts of DC sources, switches, and transformers.
Further, three of them have a high modularity degree, allowing for higher voltage operations without increasing the voltage stress across the switches.
The working principle of the proposed topologies are theoretically demonstrated, numerically verified, and experimentally validated through an in-house experimental setup.
The effectiveness of the proposed topologies is proven through detailed comparative studies regarding component counts and voltage ratings.
Prøveforelesning og disputas finner sted digitalt i konferanseprogrammet Zoom (lenke under).
Disputasen blir ledet av professor Andreas Prinz, Fakultet for teknologi og realfag, Universitetet i Agder.
Oppgitt emne for prøveforelesning: «Modular Multilevel Converter: Principles, Topology Variations and Application Areas»
Tittel på avhandling: «Multilevel Inverters with Reduced Component Count for Energy Systems»
Søk etter avhandlingen i AURA - Agder University Research Archive, som er et digitalt arkiv for vitenskapelige artikler, avhandlinger og masteroppgaver fra ansatte og studenter ved Universitetet i Agder. AURA blir jevnlig oppdatert.
Paper VI is excluded from the thesis until it is published.
Kandidaten: Ahmed Mohamed Salem Ali (1989, Luxor, Egypt) Bachelorgrad (2012 ) og mastergrad (2016) i «Electrical Engineering» fra Aswan University, Egypt. I perioden 2013 – 2016 arbeidet han i flere funksjoner ved Aswan-universitetet – som instruktør og assisterende foreleser, og som forskningsassistent ved Aswan Power Electronics Applications Research Center (APEARC) i samme periode – 2013 -2016.
Førsteopponent: Førsteamanuensis Dujic Drazen, Power Electronics Laboratory EPFL (École polytechnique fédérale de Lausanne), Sveits
Annenopponent: Seniorforsker Salvatore D’Arco, Avdeling:for energisystemer, SINTEF Energi AS
Bedømmelseskomitéen er ledet av førsteamanuensis Martin Choux, Institutt for ingeniørvitenskap, Universitetet i Agder
Veiledere i doktorgradsarbeidet var professor van Khang Huynh, UiA (hovedveileder) og professor Kjell Gunnar Robbersmyr, UiA (medveileder)
Disputasleder inviterer til spørsmål ex auditorio i innledningen i disputasen, med tidsfrister. Det er en forutsetning at opponenten har lest avhandlingen. Disputasleders e-post er tilgjengelig i chat-funksjonen under disputasen. Spørsmål om ex auditorio kan sendes til disputasleder Andreas Prinz på e-post andreas.prinz@uia.no