Fredrik Bajers Vej 5
Postboks 159 9100 Aalborg
Telefon: 9940 9940
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03.07.2017 kl. 13.00 - 16.00
Hammam Abdelaal Hammam Soliman, Department of Energy Technology, will defend the thesis "Condition Monitoring of Capacitors for DC-link Application in Power Electronic Converters".
Condition Monitoring of Capacitors for DC-link Application in Power Electronic Converters
Hammam Abdelaal Hammam Soliman
Professor Frede Blaabjerg
Associate Professor Xiongfei Wang
Associate Professor Deszo Sera, Dept. of Energy Technology, Aalborg University (Chairman)
Dr. J.J Liu, Xian Jiaotong University, China
Dr. Suresh Perinpanayagam, University of Cranfield, UK
Power electronic circuits are used in variety of applications ranging from small power supplies in computers to more specialized applications such as; satellite, airplane, medical equipment and different war-machines. In all of these applications, static power converters are an essential subsystem whose failure leads to the imminent and total stoppage of the equipment. DC-link capacitor is commonly used in all of these equipment as smoothening energy element of the converters. As a fact, in power electronics conversion systems, a single capacitor or a capacitor bank is usually used as dc-link filter. The system may be malfunction if one or more capacitor reaches end-of-life. Since failure of a single element may lead to collapse of the entire system, it is needed to develop some kind of mechanism, which will alert the operator in advance for predictive maintenance before failure, such mechanism is known as "Condition Monitoring".
Recently, the condition monitoring of dc-link capacitors to estimate their health status have been attracted by the academic research. Industry applications require more reliable power electronics products with preventive maintenances. Therefore, an in-depth analysis of prior-art condition monitoring methods (advantages, shortcomings) have been done from the following aspects: a) end-of-life indicator (e.g. C, ESR); b) how to estimate the indicator (e.g. sense current, voltage); c) algorithm to obtain the value of the indicator (online or offline); d) accuracy study and sensitivity analysis; e) hardware and software realization (reliability, cost, and complexity of the additional software algorithm and hardware circuits). From analyzing the prior-art methods it was found that, the existing capacitor condition monitoring methods suffer from either increased hardware cost or low estimation accuracy, being the challenges to be adopted in industry applications. Therefore, new development in condition monitoring technology with software solutions without extra hardware will reduce the cost, and therefore could be more promising for industry applications.
This project develops new method using an Artificial Neural Network (ANN) algorithm in order to monitor the change of the electrical parameters of electrolytic capacitors for dc-link application under stressed conditions. The application of the method is condition monitoring of capacitors under field operation in power electronic systems in order to apply predictive maintenance. The software based method is proposed in order to solve the existing issues of the prior-art research.
The ANN method estimates the end-of-life indicator (e.g. capacitance) using only the input terminal and output terminal information of the power converter, which are readily available from the feedback signals of existing digital controller. The trained ANN is implemented with the Digital Signal Processor (DSP) which normally exists for control purposes. In order to investigate the proposed method under different conditions, the ANN condition monitoring method is applied on dc-link capacitor in a Front-End diode bridge converter. Moreover, the impact of training data quality and amount on the ANN accuracy are studied. An error analysis under different dc-link capacitance values, different level of capacitance reduction with respect to the initial value under different loading conditions is also given.
Department of Energy Technology
Pontoppidanstræde 111, auditorium
15.08.2017 kl. 08.00 - 18.08.2017 kl. 18.00
From 15-18 August 2017, the 29th Congress of Nordic Historians will take place at Aalborg Congress & Culture Centre, Denmark. The main organisers are the Centre for History at the Department for Culture and Global Studies at Aalborg University, the Danish Historical Society and the Nordic Committee for Historians.
18.08.2017 kl. 13.00 - 16.00
Klinisk Institut, Aalborg Universitet og Aalborg Universitetshospital har den glæde at invitere til ph.d.-forsvar ved læge Lasse Jørgensen Cehofski, Øjenafdelingen, Aalborg Universitetshospital, som forsvarer ph.d.-afhandlingen: The Retinal Protein Profile in Experimental Branch Retinal Vein Occlusion - Interventions With an Intravitreal Anti-VEGF Agent and a Corticosteroid Implant
18.08.2017 kl. 13.00 - 16.00
Anitha Asamoah, Department of Chemistry and Bioscience, will defend her thesis on "Assessment of the Contamination Level of Persistent Organic Pollutants in Breast Milk of Ghanaian Women from a Polluted Area in Accra"
18.08.2017 kl. 13.00 - 16.00
18.08.2017 kl. 13.00 - 17.00
Maciej Plocharski will defend his ph.d. thesis: "Sulcal Morphology Analysis from MRI Data for Classification of Alzheimer’s Disease"
20.08.2017 kl. 18.00 - 22.08.2017 kl. 16.00
These are extraordinary times. Unprecedented and sustained tourism growth has transformed many cities across Europe while rural and regional areas remain unsure how they can better leverage the massive growth at their doorstep. The tourism industry is undergoing restructuring, new stakeholders are emerging, landscapes of power are shifting, and lines of responsibilities are being redrawn.
21.08.2017 kl. 13.00 - 16.00
21.08.2017 kl. 13.00 - 17.00
Steffan Wittrup Christensen will defend his Ph.D. thesis on "Neck pain – Sensory and motor effects during shoulder movements"
22.08.2017 kl. 08.00 - 24.08.2017 kl. 16.00
For the first time the Nordic Laser Materials Processing Conference is to be held in Aalborg and it is a great pleasure to invite laser scientists and industrial representatives to the 16th NOLAMP conference. We will do our best to make it an inspiring conference for researchers, industry and product developers and manufactures in the laser community.
22.08.2017 kl. 13.00 - 16.00
Farshad Badie will defend his thesis "A Theoretical Model for Meaning Construction through Constructivist Concept Learning - A Conceptual, Terminological, Logical and Semantic Study within Human-Human-Machine Interaction".
23.08.2017 kl. 09.00 - 24.08.2017 kl. 16.00
This PhD course is scheduled to follow up on the two day Tourism Education Futures Initiative (TEFI) Conference “Building our stories: Co-creating tourism futures in research and practice” (20-22 August 2017).
23.08.2017 kl. 10.00 - 15.00
Invitation to a research symposium on "Knees in the Balance - New Results in Knee Osteoarthritis Research"
24.08.2017 kl. 17.00 - 19.00
Hvordan kan ÆSTETISKE LÆREPROCESSER og KUNSTINTEGRERENDE PÆDAGOGIK åbne for nye måder at lære på? Mød kreativitetsforsker Julie Borup Jensen, der sammen med praktikere vil præsentere nye måder at lære på.
28.08.2017 kl. 09.00 - 29.08.2017 kl. 16.30
På Aalborg Universitet holdes hvert år sidst i august konferencen Trafikdage hvor 300 deltagere præsenterer forskningsresultater, analyser samt praktiske erfaringer fra transportsektoren. Deltagerne er både forskere & praktikere, men også politikere og presse – fordi det er vigtigt at understøtte dialog og udbygge netværk.
28.08.2017 kl. 13.00 - 16.00
Title of the thesis: Dwelling in Mundane Mobility: Caravanning in Denmark.