Volume 13, number 1, 2019. Print version and published papers:

AWARENESS OF DEMAND-SIDE MANAGEMENT PRACTICES AMONG STAFF OF AN EDUCATIONAL INSTITUTION

Emmanuel Asuming FRIMPONG, Elvis TWUMASI, Department of Electrical and Electronic Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, eafrimpong.soe@knust.edu.gh, elvistwumasi@gmail.com

Keywords: energy conservation, energy efficiency, energy wastage

Abstract: Awareness of demand-side management practices among staff of educational institutions is critical for energy savings. This paper presents the results of a survey to determine the extent to which staff of the Kwame Nkrumah University of Science and Technology are aware of measures for energy efficiency and also assess their preparedness to support efforts towards reducing energy wastage. Questionnaires were administered to Senior members, Senior staff and Junior staff of the institution. The questionnaires were designed to collect data on their level of energy efficiency awareness in the use of refrigerators, airconditioners, light bulbs and electronic devices. The extent to which staff are engaged in energy saving activities and their preparedness to get involved in energy saving activities were also determined. The analysis of the collected data was done using the Statistical Package for Social Sciences (SPSS) software. Analysis of responses received show that more than seventy-seven percent of staff are ignorant of the fact that keeping refrigerators close to walls resulted in energy wastage. About fifty-seven percent of them are aware of the fact that when airconditioners are not cleaned regularly, much energy is wasted. Almost eighty-five percent of staff indicated awareness of the fact that keeping electronic devices on standby for long periods could be a source of significant energy wastage. Over eighty-three percent of staff indicated that they had been switching light bulbs off when there is adequate illumination from the sun so as to conserve energy. About thirty-six percent of staff are already engaged in at least one form of energy conservation. Lastly, over 94% of them expressed willingness to take part in energy saving activities.

OPTIMIZED SPACE-VECTOR-MODULATED QUASI Z-SOURCE NPC INVERTER FOR SOLAR PV APPLICATION

Francis EFFAH¹, Philip OKYERE¹, Patrick WHEELER², Alan WATSON² , Jon CLARE², ¹ Kwame Nkrumah University of Scince and Technology, Kumasi, Ghana, ²University of Nottingham, Nottingham, UK, fbeffah.coe@knust.edu.gh

Keywords: buck-boost, single-stage, neutral point clamped, space vector modulation

Abstract: An optimized space vector modulation technique for controlling a quasi Z-source NPC inverter for solar photovoltaic application is presented in this paper. The presented algorithm optimizes the number of switching transitions over a switching cycle by modifying the placement of the shoot-through states in some of the sub-triangles of the space vector diagram of a conventional neutral point clamped inverter. This approach leads to a reduction in the total losses of the quasi Z-source inverter by reducing the switching losses. The presented concepts are expected to be cheaper than existing methods because a reduction in losses will lead to the use of smaller and cheaper heat sinks in practical implementation. In this paper, the effectiveness of the proposed optimized space vector modulation technique has been demonstrated through simulations in SABER®.

DIAGNOSIS OF BEARING DEFECTS BY ANFIS IN THE INDUCTION MOTOR

Nabil TALBI¹ , Abderrezak METATLA¹ , Toufik SEBBAGH¹ , NadirBOUTASSETA², Mohamed HASSAN², ¹Department of Mechanical Engineering, Faculty of Technology, Université 20 août 1955 Skikda BP 26 Road of El hadaiek, Skikda, Algeria, ²Research Center in Industrial Technologies CRTI, P.O.Box 64, Cheraga, Algeria, n.talbi@ univ-skikda.dz, a.metatla@ univ-skikda.dz, t.sebbagh@ univ-skikda.dz, boutasseta@gmail.com, moha82.hassani@hotmail.fr² Research Center in Industrial Technologies CRTI, P.O.Box 64, Cheraga, Algeria, n.talbi@ univ-skikda.dz, a.metatla@ univ-skikda.dz, t.sebbagh@ univ-skikda.dz, boutasseta@gmail.com, moha82.hassani@hotmail.fr

Keywords: fault diagnosis, ANFIS, parameter extraction, induction motor, fault classification

Abstract: In this paper, we developed a robust technique for fault classification in the induction motor, which was used by the Adaptive Network Reference Information System (ANFIS). A robustness and precision test of the proposed method was performed on a small database. To speed up the response and minimize the calculation time, the most sensitive indicators have been used to ensure the learning of the classifier. The database used was carried out at the University of Case Western, this database has two modes of healthy operation and with rolling defects located side coupling. The objective of the technique used in this paper is to extract the indicators and to test them to select the most sensitive to the apparition of defects. The obtained results show the effectiveness and sensitivity of the proposed approach to identify the nature of the defect even at the birth stage.

OPTIMIZATION AND CONTROL STRATEGY OF MULTI-SOURCE SYSTEM USING GENETIC ALGORITHM

Amina GABOUR, Samia BENZAHIOUL, Abbderrezak METATLA, Toufik SEBBAGH, LGMM Laboratory, Université 20 Aout 1955 – Skikda, Algeria, a.gabour@univ-skikda.dz, sbenzahioul@univ-skikda.dz, a.metatla@univ-skikda.dz, t.sebbagh@univ-skikda.dz

Keywords: multi-source system, optimization, control, GA

Abstract:The aim of this paper is to design the sizing and optimization of multi-source system PV/Diesel/Battery, whereat the power management algorithm is applied to feed load in Algeria where the GA method is used to find the best configuration of the system and for sizing purpose of the components, based on the minimum total cost of the system (STC) subject to renewable energy fraction (FR).Thus, the results show the impact of RF on the STC in addition to the choice of the best configuration and the most adequate one.

THREE-LEVEL INDIRECT MATRIX CONVERTER WITH TWO SERIES Z-SOURCE NETWORKS

Francis Boafo EFFAH¹, Philip OKYERE¹, Mubarak Sani ELLIS¹, Patrick WHEELER², Alan WATSON²,Jon CLARE², Joseph OJO³, ¹Kwame Nkrumah University of Science and Technology, Kumasi, Ghana, ²University of Nottingham, UK, ³Tennessee Technological University Cookeville, USA. fbeffah.coe@knust.edu.gh

Keywords: series Z-source, cascaded Z-source, partial shoot-through, virtual space vector modulation

Abstract: In previous articles, the concept of series Z-source network has been extended to conventional indirect matrix converter to raise the voltage gain to unity and beyond. In this paper, this idea is modified and applied to a three-level indirect matrix converter. Two series Z-source networks are placed on the virtual dc-link between a rectifier and a neutral point clamped inverter on the positive and negative dc rails. Partial shoot-through states are used for voltage boosting. The series Z-source capacitor voltages and starting current stresses are reduced. A virtual space vector PWM method has been developed to ensure voltage boost ability of the converter. Simulation results from SABER are used to demonstrate the superiority of the proposed converter over the existing topology.

LIMITS OF EXPOSURE TO ELECTROMAGNETIC FIELDS – A REVIEW OF STANDARDS AND REGULATIONS

Mihaela ȘTEȚ, Technical University of Cluj-Napoca, Romania, Mihaela.Stet@cunbm.utcluj.ro

Keywords: regulations, electromagnetic exposure, standards, radiofrequency

Abstract: Identification of risks and potential effects of exposure to electromagnetic fields has aroused the interest of researchers in various fields to reduce or even eliminate them. However, the problems they raise, also, determined the need to regulate the exposure limits, thus establishing a series of regulations at the level of different states, of some national and international standards. The paper presents a comparative analysis of several national and international regulations regarding the exposure limits for the general public and for different working environments.