Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021188
D. Gospodinova, M. Neznakomova
There are two approaches to give textile fibers nutraceutical properties: microencapsulation, which is the final step in the textile finishing process for traditional textile fibers, and the addition of specific additives during the fiberization process. In the present manuscript, in order to produce mats with wellness benefits, two types of solutions containing Aloe vera were added to an aqueous solution of PVA (polyvinyl alcohol) and electrospun to produce nanofibers. The procedure was carried out using the same electrical conditions for pure PVA solution fiberization potential. The diameter, defect count, and coverage areas of the resultant fibres are all measured. The Well Ness product was discovered to be microencapsulated within the bulk of the resulting fibers.
{"title":"Investigation of the Effect of Polymer Solution Electrospinning System Parameters on the Nanofibers Morphology","authors":"D. Gospodinova, M. Neznakomova","doi":"10.1109/BulEF56479.2022.10021188","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021188","url":null,"abstract":"There are two approaches to give textile fibers nutraceutical properties: microencapsulation, which is the final step in the textile finishing process for traditional textile fibers, and the addition of specific additives during the fiberization process. In the present manuscript, in order to produce mats with wellness benefits, two types of solutions containing Aloe vera were added to an aqueous solution of PVA (polyvinyl alcohol) and electrospun to produce nanofibers. The procedure was carried out using the same electrical conditions for pure PVA solution fiberization potential. The diameter, defect count, and coverage areas of the resultant fibres are all measured. The Well Ness product was discovered to be microencapsulated within the bulk of the resulting fibers.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130934453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021198
V. Dimitrov
The paper proposes the implementation of a high degree of automation in electric vehicles. The developed method uses PLC, sensors providing the required information and a database with pre-recorded characteristics. Various examinations of a frequency controlled asynchronous electrical drive are described and the obtained characteristics are digitized. They can be recorded as a database in the PLC and can be used for real time control of the vehicles. During operation, the information received from the sensors can be compared with these pre-recorded characteristics and the optimal control mode selected. If a deviation occurs, a fault (failure or malfunction) could be identified immediately, and a signal sent. The proposed method provides a quick response to changes in load, increased energy efficiency and reduced current and torque ripples.
{"title":"Experimental research of asynchronous drives and digitization of the characteristics","authors":"V. Dimitrov","doi":"10.1109/BulEF56479.2022.10021198","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021198","url":null,"abstract":"The paper proposes the implementation of a high degree of automation in electric vehicles. The developed method uses PLC, sensors providing the required information and a database with pre-recorded characteristics. Various examinations of a frequency controlled asynchronous electrical drive are described and the obtained characteristics are digitized. They can be recorded as a database in the PLC and can be used for real time control of the vehicles. During operation, the information received from the sensors can be compared with these pre-recorded characteristics and the optimal control mode selected. If a deviation occurs, a fault (failure or malfunction) could be identified immediately, and a signal sent. The proposed method provides a quick response to changes in load, increased energy efficiency and reduced current and torque ripples.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128736584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021200
I. Angelov
The actual average values of the impedance of traction networks operated in Bulgaria are used in the work. Impedance values are measured during controlled short-circuits in different feeder zones. Based on a computer model, the traction network reactions during a short-circuit are checked. A physical model was developed for simulating short-circuits in traction nets at different distances from the traction substation and the used voltage and current transformers.
{"title":"Physical Model of AC Traction Networks for Simulating Emergency Modes","authors":"I. Angelov","doi":"10.1109/BulEF56479.2022.10021200","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021200","url":null,"abstract":"The actual average values of the impedance of traction networks operated in Bulgaria are used in the work. Impedance values are measured during controlled short-circuits in different feeder zones. Based on a computer model, the traction network reactions during a short-circuit are checked. A physical model was developed for simulating short-circuits in traction nets at different distances from the traction substation and the used voltage and current transformers.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"46 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127996271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021190
V. Mladenov, V. Chobanov, Verzhinia Ivanova
Business models are an integral part of any innovation and change in how certain economic activities and relationships are carried out. Business models are of use of already existing or improved product/services, definition of market participant roles or even when a new project is planning. Driven by the energy transformation (change in both energy production and consumption behavior), a solution is proposed for the challenges that strives to enable DSO to procure flexibility services (intentional change in production/consumption at and for a certain period of time in a specific location against remuneration).
{"title":"DSO flexibility services Business Model Canvas","authors":"V. Mladenov, V. Chobanov, Verzhinia Ivanova","doi":"10.1109/BulEF56479.2022.10021190","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021190","url":null,"abstract":"Business models are an integral part of any innovation and change in how certain economic activities and relationships are carried out. Business models are of use of already existing or improved product/services, definition of market participant roles or even when a new project is planning. Driven by the energy transformation (change in both energy production and consumption behavior), a solution is proposed for the challenges that strives to enable DSO to procure flexibility services (intentional change in production/consumption at and for a certain period of time in a specific location against remuneration).","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129149156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021168
D. Pavlov, Dilyan Ivanov
In order to save electrical energy, in the last ten years, LED lighting fixtures have replaced the fluorescent lighting fixtures used for indoor lighting, especially those in educational and administrative buildings. The LED illuminators have the same overall dimensions and luminous flux as the replaced ones, but with significantly less consumed power. Often, reducing lighting costs leads to neglecting some of the others qualitative and quantitative indicators of light sources, such as color rendering, light distribution curve, pulsations, etc. In this report, the possibilities for the reconstruction of existing lighting arrangements will be considered, and quantitative and qualitative indicators in these laboratories will be measured.
{"title":"Methods to Improve Quantitative and Qualitative Indicators of Lighting in Classrooms","authors":"D. Pavlov, Dilyan Ivanov","doi":"10.1109/BulEF56479.2022.10021168","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021168","url":null,"abstract":"In order to save electrical energy, in the last ten years, LED lighting fixtures have replaced the fluorescent lighting fixtures used for indoor lighting, especially those in educational and administrative buildings. The LED illuminators have the same overall dimensions and luminous flux as the replaced ones, but with significantly less consumed power. Often, reducing lighting costs leads to neglecting some of the others qualitative and quantitative indicators of light sources, such as color rendering, light distribution curve, pulsations, etc. In this report, the possibilities for the reconstruction of existing lighting arrangements will be considered, and quantitative and qualitative indicators in these laboratories will be measured.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131057599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021148
Kamen Vasilev, Valentin Kolev, Iva Draganova-Zlateva
This report examines the possibilities of using the infrastructure of the Transmission System Operator (ESO) and, in particular, the step-down substations in the transmission electricity network for powering charging stations for electric vehicles.
{"title":"Concept for building and managing a national infrastructure of charging stations for electric cars near substations, part of the electricity transmission network of Bulgaria","authors":"Kamen Vasilev, Valentin Kolev, Iva Draganova-Zlateva","doi":"10.1109/BulEF56479.2022.10021148","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021148","url":null,"abstract":"This report examines the possibilities of using the infrastructure of the Transmission System Operator (ESO) and, in particular, the step-down substations in the transmission electricity network for powering charging stations for electric vehicles.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132695612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021183
Anelia I. Tzanova, A. Zahariev, N. Kaloyanov, K. Ruskova
This article presents the results of the process of biomethanization and joint biodegradation of manure from cows (reference sample), a mixture of the same manure and household waste of fruit-vegetable origin (peelings), as well as a mixture of the manure and bismuth complex of p-toluenesulfonic acid. The samples are incubated at 34.5 degrees Celsius, under nitrogen atmosphere, during 30 days, periodically measuring the volume of biogas and the percentage of methane. From the results obtained, one can see that during entire period of the experiment, the mixture containing cow manure and household waste of fruit-vegetable origin produce the largest amount of biogas, compared to the other two samples. However, regarding the methane content in all samples, its amount in this mixture is the least. During the measurement period, mixture containing the complex $[mathbf{Bi}_{6}mathbf{O}_{6}(mathbf{OH})_{3}](mathbf{C}_{7}mathbf{H}_{7}mathbf{SO}_{3})_{{3}}$ always show a larger amount of biogas produced, compared to the reference sample. It is noteworthy that the biogas produced by this sample always depicts the highest percentage of methane, compared to other two samples.
{"title":"Influence of novel $boldsymbol{[Bi_{6}O_{6}(OH)_{3}]({C}_{7}H_{7}SO_{3})3}$ complex on the biogas production","authors":"Anelia I. Tzanova, A. Zahariev, N. Kaloyanov, K. Ruskova","doi":"10.1109/BulEF56479.2022.10021183","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021183","url":null,"abstract":"This article presents the results of the process of biomethanization and joint biodegradation of manure from cows (reference sample), a mixture of the same manure and household waste of fruit-vegetable origin (peelings), as well as a mixture of the manure and bismuth complex of p-toluenesulfonic acid. The samples are incubated at 34.5 degrees Celsius, under nitrogen atmosphere, during 30 days, periodically measuring the volume of biogas and the percentage of methane. From the results obtained, one can see that during entire period of the experiment, the mixture containing cow manure and household waste of fruit-vegetable origin produce the largest amount of biogas, compared to the other two samples. However, regarding the methane content in all samples, its amount in this mixture is the least. During the measurement period, mixture containing the complex $[mathbf{Bi}_{6}mathbf{O}_{6}(mathbf{OH})_{3}](mathbf{C}_{7}mathbf{H}_{7}mathbf{SO}_{3})_{{3}}$ always show a larger amount of biogas produced, compared to the reference sample. It is noteworthy that the biogas produced by this sample always depicts the highest percentage of methane, compared to other two samples.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123774310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021173
T. Totev, B. Ignatov, Vasil Radenkov
One of the technical solutions for the reduction of CO2 emissions in the atmosphere is its capturing and geological storage which leads to numerous problems. One of the major issues associated with that solution is the significant energy cost of the CO2 separation process. This paper assesses the possibility of oxy-fuel integration for a CCGT plant which leads to a composition of only CO2, O2 and water vapors as well as a lack of N2 in the outlet flue gas, resulting in a significant reduction of the required energy for CO2 geological storage.
{"title":"Oxy-fuel combustion in CCGT","authors":"T. Totev, B. Ignatov, Vasil Radenkov","doi":"10.1109/BulEF56479.2022.10021173","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021173","url":null,"abstract":"One of the technical solutions for the reduction of CO2 emissions in the atmosphere is its capturing and geological storage which leads to numerous problems. One of the major issues associated with that solution is the significant energy cost of the CO2 separation process. This paper assesses the possibility of oxy-fuel integration for a CCGT plant which leads to a composition of only CO2, O2 and water vapors as well as a lack of N2 in the outlet flue gas, resulting in a significant reduction of the required energy for CO2 geological storage.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"350 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116501708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021192
M. Todorova, I. Marinova, V. Mateev
The subject of this paper is an investigation of the mechanical stress in rotational coaxial magnetic gear, caused by magnetic torque. The magnets, utilized in the construction of the gear, are Alnico, ferrite, Samarium-Cobalt and Neodymium Iron Boron magnets. Their compressive stress value is evaluated and compared with material strength values for all four types of the magnets. The compressive strengths of one magnet's segments of the outer rotor of the magnetic gear are also evaluated. Ansys Maxwell is used for modelling of magnetic torque of the gear under investigation.
{"title":"Permanent Magnet's Mechanical Strength in Rotational Magnetic Gears","authors":"M. Todorova, I. Marinova, V. Mateev","doi":"10.1109/BulEF56479.2022.10021192","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021192","url":null,"abstract":"The subject of this paper is an investigation of the mechanical stress in rotational coaxial magnetic gear, caused by magnetic torque. The magnets, utilized in the construction of the gear, are Alnico, ferrite, Samarium-Cobalt and Neodymium Iron Boron magnets. Their compressive stress value is evaluated and compared with material strength values for all four types of the magnets. The compressive strengths of one magnet's segments of the outer rotor of the magnetic gear are also evaluated. Ansys Maxwell is used for modelling of magnetic torque of the gear under investigation.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128869794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.1109/BulEF56479.2022.10021162
V. Totev, V. Gueorgiev
Pulse - width modulation has been established as the most widely utilized algorithm in methods of control of electric drives, regardless of their application. It can be easily performed in scalar control to regulate angular velocity. Whenever precise positioning or precise displacement/ precise rotation is required, pulse -width modulation is employed by utilization of vector control (field - oriented control). Generally, the most commonly used practice of vector control is to transform electrical quantities in d-q plane by Clarke's and Park's transformation, which are then compared with the respective desired torque or speed inputs by PI controllers and further transformed back by the inverse transformations. However, with utilization of space vector modulation, transformations can be reduced, voltage utilization can be improved. In this paper a comparison between different types of space vector modulation for electric vehicle's application is presented. Comparison is done on the basis of simulation results which are verified by a laboratory stand, comprised of permanent magnet synchronous motors.
{"title":"Comparison of different types of space vector modulation for electric vehicle's application","authors":"V. Totev, V. Gueorgiev","doi":"10.1109/BulEF56479.2022.10021162","DOIUrl":"https://doi.org/10.1109/BulEF56479.2022.10021162","url":null,"abstract":"Pulse - width modulation has been established as the most widely utilized algorithm in methods of control of electric drives, regardless of their application. It can be easily performed in scalar control to regulate angular velocity. Whenever precise positioning or precise displacement/ precise rotation is required, pulse -width modulation is employed by utilization of vector control (field - oriented control). Generally, the most commonly used practice of vector control is to transform electrical quantities in d-q plane by Clarke's and Park's transformation, which are then compared with the respective desired torque or speed inputs by PI controllers and further transformed back by the inverse transformations. However, with utilization of space vector modulation, transformations can be reduced, voltage utilization can be improved. In this paper a comparison between different types of space vector modulation for electric vehicle's application is presented. Comparison is done on the basis of simulation results which are verified by a laboratory stand, comprised of permanent magnet synchronous motors.","PeriodicalId":375606,"journal":{"name":"2022 14th Electrical Engineering Faculty Conference (BulEF)","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132749419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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