1.
Ivanova, Y.; Ivanov, S.
Dv/Dt Control through the Gate of a Field-Effect Transistor in Forward-Mode Converters Conference
2021, ISBN: 9781665440615.
Abstract | Links | BibTeX | Етикети: e, ee
@conference{Ivanova2021,
title = {Dv/Dt Control through the Gate of a Field-Effect Transistor in Forward-Mode Converters},
author = {Y. Ivanova and S. Ivanov},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114125968\&doi=10.1109%2fELECTRONICA52725.2021.9513730\&partnerID=40\&md5=ca046cc88e447a9e5653b1b7543a7aba},
doi = {10.1109/ELECTRONICA52725.2021.9513730},
isbn = {9781665440615},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {12th National Conference with International Participation, ELECTRONICA 2021 - Proceedings},
abstract = {An important condition for increasing the efficiency of pulse converters is the reduction of active power losses on switch transistors during transients. In addition to reducing the duration of the on and off times, it is necessary to reduce the amplitude values of the currents and voltages of the switch transistor. This paper presents a study of the transients in the control of a forward pulsed voltage stabilizer. A comparative analysis was made between control of the switch transistor with a conventional and with an active driver with feedback on the derivative of drain voltage. The electromagnetic compatibility of the pulse converter is improved by reducing the maximum values of currents and voltages as well as the duration of the transients. © 2021 IEEE.},
keywords = {e, ee},
pubstate = {published},
tppubtype = {conference}
}
An important condition for increasing the efficiency of pulse converters is the reduction of active power losses on switch transistors during transients. In addition to reducing the duration of the on and off times, it is necessary to reduce the amplitude values of the currents and voltages of the switch transistor. This paper presents a study of the transients in the control of a forward pulsed voltage stabilizer. A comparative analysis was made between control of the switch transistor with a conventional and with an active driver with feedback on the derivative of drain voltage. The electromagnetic compatibility of the pulse converter is improved by reducing the maximum values of currents and voltages as well as the duration of the transients. © 2021 IEEE.
2.
Yatchev, I.; Balabozov, I.; Hinov, K.; Hadzhiev, I.; Gueorgiev, V.
Influence of the shape of the input pulses on the characteristics of hybrid electromagnetic system with magnetic flux modulation Journal Article
In: Electrical Engineering and Electromechanics, no. 3, pp. 3-7, 2021, ISSN: 2074272X.
Abstract | Links | BibTeX | Етикети: ee
@article{Yatchev20213,
title = {Influence of the shape of the input pulses on the characteristics of hybrid electromagnetic system with magnetic flux modulation},
author = {I. Yatchev and I. Balabozov and K. Hinov and I. Hadzhiev and V. Gueorgiev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85120031146\&doi=10.20998%2f2074-272X.2021.3.01\&partnerID=40\&md5=fbf80aed5fb98c92c128f67e55cd745a},
doi = {10.20998/2074-272X.2021.3.01},
issn = {2074272X},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Electrical Engineering and Electromechanics},
number = {3},
pages = {3-7},
abstract = {Introduction. Nowadays, the accelerated development of materials and technologies and the finding of new ones is a prerequisite for the improvement of well-known electromagnetic constructions used in various devices, as well as for the development of new ones. New construction of hybrid electromagnetic system with magnetic flux modulation (HEMSMM) is studied. The construction is composed of: ferromagnetic frame with air gaps, input and output coils and permanent magnets. Two input coils connected to the pulsed power supply are used to change the path of the generated by the permanent magnets constant magnetic flux. Input pulses with different shapes are applied to the input coils and signals in the output coils are obtained and compared. The main purpose of the work is to find the shape of the input pulses which leads to higher output power in comparison with the other shapes. Methods. Finite element method and COMSOL software is used for computer modelling of the proposed construction, where coupled electromagnetic field \textendash electric circuit analysis is carried out. Results. A mathematical and numerical 3D model of new HEMSMM construction is realised and studied. The model allows to calculate and compare power efficiency of the studied device, when input pulses with different shapes are applied. Practical value. The developed computer model enables the study of the HEMSMM and other electromagnetic devices at different operating modes. It can be further improved and used in the search for optimal parameters of a particular electromagnetic device. References 13, table 1, figures 13. © I. Yatchev, I. Balabozov, K. Hinov, I. Hadzhiev, V. Gueorgiev.},
keywords = {ee},
pubstate = {published},
tppubtype = {article}
}
Introduction. Nowadays, the accelerated development of materials and technologies and the finding of new ones is a prerequisite for the improvement of well-known electromagnetic constructions used in various devices, as well as for the development of new ones. New construction of hybrid electromagnetic system with magnetic flux modulation (HEMSMM) is studied. The construction is composed of: ferromagnetic frame with air gaps, input and output coils and permanent magnets. Two input coils connected to the pulsed power supply are used to change the path of the generated by the permanent magnets constant magnetic flux. Input pulses with different shapes are applied to the input coils and signals in the output coils are obtained and compared. The main purpose of the work is to find the shape of the input pulses which leads to higher output power in comparison with the other shapes. Methods. Finite element method and COMSOL software is used for computer modelling of the proposed construction, where coupled electromagnetic field – electric circuit analysis is carried out. Results. A mathematical and numerical 3D model of new HEMSMM construction is realised and studied. The model allows to calculate and compare power efficiency of the studied device, when input pulses with different shapes are applied. Practical value. The developed computer model enables the study of the HEMSMM and other electromagnetic devices at different operating modes. It can be further improved and used in the search for optimal parameters of a particular electromagnetic device. References 13, table 1, figures 13. © I. Yatchev, I. Balabozov, K. Hinov, I. Hadzhiev, V. Gueorgiev.
3.
Ivanov, S. C.; Ivanova, Y. N.
Optimization of switching performance of power MOSFET with active driver with dv/dt feedback Conference
2021, ISBN: 9781665435826.
Abstract | Links | BibTeX | Етикети: e, ee
@conference{Ivanov2021,
title = {Optimization of switching performance of power MOSFET with active driver with dv/dt feedback},
author = {S. C. Ivanov and Y. N. Ivanova},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114912001\&doi=10.1109%2fELMA52514.2021.9503078\&partnerID=40\&md5=e0e4c86858ded19b24128a2dafcd4726},
doi = {10.1109/ELMA52514.2021.9503078},
isbn = {9781665435826},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {2021 17th Conference on Electrical Machines, Drives and Power Systems, ELMA 2021 - Proceedings},
abstract = {Using an active driver with feedback on a derivative of drain voltage dv/dt to reduce high-order harmonic frequencies and reduce active losses in MOSFET control is researched and analyzed in this paper. Studies have been performed in the control of R-L load and supply voltage 12V. A comparison is made between the exponential change of the current through the load in controlling with a standard driver and change of current when driving with active driver. The article found that the active driver reduces the active power losses on the transistor. The studied active driver is suitable for control of DC-DC converters operating by the method of pulse-width modulation. © 2021 IEEE.},
keywords = {e, ee},
pubstate = {published},
tppubtype = {conference}
}
Using an active driver with feedback on a derivative of drain voltage dv/dt to reduce high-order harmonic frequencies and reduce active losses in MOSFET control is researched and analyzed in this paper. Studies have been performed in the control of R-L load and supply voltage 12V. A comparison is made between the exponential change of the current through the load in controlling with a standard driver and change of current when driving with active driver. The article found that the active driver reduces the active power losses on the transistor. The studied active driver is suitable for control of DC-DC converters operating by the method of pulse-width modulation. © 2021 IEEE.
4.
Stoykova, E.; Nazarova, D.; Nenchev, M.; Deneva, M.
Modelling of transmission for a stack of two Fizeau wedges with matched parameters Conference
vol. 11783, 2021, ISSN: 0277786X.
Abstract | Links | BibTeX | Етикети: ee
@conference{Stoykova2021,
title = {Modelling of transmission for a stack of two Fizeau wedges with matched parameters},
author = {E. Stoykova and D. Nazarova and M. Nenchev and M. Deneva},
editor = {Frenner K. Bodermann B.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85109592789\&doi=10.1117%2f12.2592651\&partnerID=40\&md5=53be8a2777af7cbbb17f256de6506254},
doi = {10.1117/12.2592651},
issn = {0277786X},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Proceedings of SPIE - The International Society for Optical Engineering},
volume = {11783},
abstract = {A conventional Fizeau wedge (FW) is built of two flat reflecting surfaces inclined at a small angle. They form a gap with linearly increasing thickness normally to the wedge ridge. Such FWs with apex angles of 5-100 microradians and 5-1000 micrometers thickness find application in optical metrology, spectroscopy and laser spectral control. The apex angle, the reflection coefficients and the refractive index in the gap form a unique interference pattern on both FW's sides. To benefit from a large free spectral range of thin wedges and high spectral resolution of thick wedges, recently we proposed a stack of two FWs with matched parameters. Matching provides the same change of the resonant wavelength at the same lateral displacement of both wedges. The aim of this study is to develop a technique for calculation of the resultant transmission of the stack of two matched wedges at plane wave illumination that is based on determination of the number and optical path differences of the rays leaving the stack at a given point on its rear surface. Only rays with non-negligible contribution as an amplitude are taken into account. Numerical simulation and experimental verification are provided. © 2021 SPIE.},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
A conventional Fizeau wedge (FW) is built of two flat reflecting surfaces inclined at a small angle. They form a gap with linearly increasing thickness normally to the wedge ridge. Such FWs with apex angles of 5-100 microradians and 5-1000 micrometers thickness find application in optical metrology, spectroscopy and laser spectral control. The apex angle, the reflection coefficients and the refractive index in the gap form a unique interference pattern on both FW's sides. To benefit from a large free spectral range of thin wedges and high spectral resolution of thick wedges, recently we proposed a stack of two FWs with matched parameters. Matching provides the same change of the resonant wavelength at the same lateral displacement of both wedges. The aim of this study is to develop a technique for calculation of the resultant transmission of the stack of two matched wedges at plane wave illumination that is based on determination of the number and optical path differences of the rays leaving the stack at a given point on its rear surface. Only rays with non-negligible contribution as an amplitude are taken into account. Numerical simulation and experimental verification are provided. © 2021 SPIE.
5.
Deneva, M.; Nenchev, M.
vol. 1859, no. 1, 2021, ISSN: 17426588.
Abstract | Links | BibTeX | Етикети: ee
@conference{Deneva2021,
title = {Integrated interference wedged structures as a basis for creating compact light beam splitters with improved parameters},
author = {M. Deneva and M. Nenchev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104248048\&doi=10.1088%2f1742-6596%2f1859%2f1%2f012020\&partnerID=40\&md5=5c5b544b0508486cc138f722415119d5},
doi = {10.1088/1742-6596/1859/1/012020},
issn = {17426588},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Journal of Physics: Conference Series},
volume = {1859},
number = {1},
abstract = {Based on the idea of combining in one plate and in a puzzle-type of properly designed parts of planar sheet-like interference wedged structures (IWS), including the composed interference wedged structure (CIWS) developed by us, we show the possibility of realizing new integrated light beam splitters (for laser beams) that have useful competitive properties. Using our theoretical approach for analysis of IWS, simulations and test experiments, we show that such optimized splitters ensure a smooth splitting in an increased linear variation range of the transmission T (from ~ 80-95% to 5%) and reflection (R = 1-T), in combination with a large working range (linear splitting by sliding to more than ~15-20 mm). The low slope of the transmission variation permits one to split beams of diameter 3-5 mm; focusing the beam increases this range to more than ~15 mm. The control is performed by sliding the splitter in its plane (dimensions ~ 5×2×0.1 cm3) thus conserving the direction of the formed beams. No specific polarization is required and the use is possible of high-power laser beams. A suitable practical realization is the use of a mask technology for sequential deposition of necessary layers in integrated circuits. © 2021 Published under licence by IOP Publishing Ltd.},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
Based on the idea of combining in one plate and in a puzzle-type of properly designed parts of planar sheet-like interference wedged structures (IWS), including the composed interference wedged structure (CIWS) developed by us, we show the possibility of realizing new integrated light beam splitters (for laser beams) that have useful competitive properties. Using our theoretical approach for analysis of IWS, simulations and test experiments, we show that such optimized splitters ensure a smooth splitting in an increased linear variation range of the transmission T (from ~ 80-95% to 5%) and reflection (R = 1-T), in combination with a large working range (linear splitting by sliding to more than ~15-20 mm). The low slope of the transmission variation permits one to split beams of diameter 3-5 mm; focusing the beam increases this range to more than ~15 mm. The control is performed by sliding the splitter in its plane (dimensions ~ 5×2×0.1 cm3) thus conserving the direction of the formed beams. No specific polarization is required and the use is possible of high-power laser beams. A suitable practical realization is the use of a mask technology for sequential deposition of necessary layers in integrated circuits. © 2021 Published under licence by IOP Publishing Ltd.
6.
Nenchev, M.; Deneva, M.; Marinova, M.
vol. 1859, no. 1, 2021, ISSN: 17426588.
Abstract | Links | BibTeX | Етикети: cst, ee
@conference{Nenchev2021,
title = {Competitive light beam splitters based on complex interference wedged structures that use low-reflectivity components (Fresnel reflection)},
author = {M. Nenchev and M. Deneva and M. Marinova},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104268254\&doi=10.1088%2f1742-6596%2f1859%2f1%2f012021\&partnerID=40\&md5=4f64ec553e7218abb7f9e286fda2d476},
doi = {10.1088/1742-6596/1859/1/012021},
issn = {17426588},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Journal of Physics: Conference Series},
volume = {1859},
number = {1},
abstract = {We demonstrate that interference wedge structures suitably composed of wedged purely glass elements using Fresnel reflection only can be effectively employed for realization of competitive light beam splitters and filters (especially for high-power laser beams). The theoretical analysis, simulation and experimental testing show that for appropriately chosen parameters and for a suitably composed interference complex such structures can achieve a controlled variable transmission in a wide range (99%-~30%) and reflection from ~2% to ~70%. The traditional realization of purely glass splitters ensures no more than ~20% reflectivity. The splitters proposed are very compact sheet-like elements (e.g., 5×3×0.2 cm) and the splitting is implemented by sliding in the splitter's plane. Thus, the propagation direction of the formed beams is preserved. The incident beam on the purely glass splitter (no dielectric or metallic mirrors) can be of high power and the influence of the air humidity is strongly reduced; also, cleaning the filter surfaces presents no difficulties. A single splitter can work in a wide range of wavelengths (IR, visible) without polarization dependence for incident angles up to ~20°. © 2021 Published under licence by IOP Publishing Ltd.},
keywords = {cst, ee},
pubstate = {published},
tppubtype = {conference}
}
We demonstrate that interference wedge structures suitably composed of wedged purely glass elements using Fresnel reflection only can be effectively employed for realization of competitive light beam splitters and filters (especially for high-power laser beams). The theoretical analysis, simulation and experimental testing show that for appropriately chosen parameters and for a suitably composed interference complex such structures can achieve a controlled variable transmission in a wide range (99%-~30%) and reflection from ~2% to ~70%. The traditional realization of purely glass splitters ensures no more than ~20% reflectivity. The splitters proposed are very compact sheet-like elements (e.g., 5×3×0.2 cm) and the splitting is implemented by sliding in the splitter's plane. Thus, the propagation direction of the formed beams is preserved. The incident beam on the purely glass splitter (no dielectric or metallic mirrors) can be of high power and the influence of the air humidity is strongly reduced; also, cleaning the filter surfaces presents no difficulties. A single splitter can work in a wide range of wavelengths (IR, visible) without polarization dependence for incident angles up to ~20°. © 2021 Published under licence by IOP Publishing Ltd.
7.
Raychev, R.; Georgiev, N.
Study of linear generators with and without rotating permanent magnets in their stator windings Conference
2021, ISBN: 9781665435826.
Abstract | Links | BibTeX | Етикети: ee
@conference{Raychev2021,
title = {Study of linear generators with and without rotating permanent magnets in their stator windings},
author = {R. Raychev and N. Georgiev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85114954776\&doi=10.1109%2fELMA52514.2021.9503053\&partnerID=40\&md5=b7169ba77bb6f9f83b10b70d9a3dc5a0},
doi = {10.1109/ELMA52514.2021.9503053},
isbn = {9781665435826},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {2021 17th Conference on Electrical Machines, Drives and Power Systems, ELMA 2021 - Proceedings},
abstract = {The paper examines linear generators with and without rotating magnets in their stator windings. A three-dimensional model in dynamic mode has been synthesized with the help of ANSYS R19.1. The influence of the dimensions of the permanent magnets in the double sided translators on the electrical parameters of the generators has also been analyzed. Experimental studies of the generators have been performed to prove the accuracy of the simulation model. © 2021 IEEE.},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
The paper examines linear generators with and without rotating magnets in their stator windings. A three-dimensional model in dynamic mode has been synthesized with the help of ANSYS R19.1. The influence of the dimensions of the permanent magnets in the double sided translators on the electrical parameters of the generators has also been analyzed. Experimental studies of the generators have been performed to prove the accuracy of the simulation model. © 2021 IEEE.
8.
Stefanov, S B; Georgiev, A P
vol. 878, no. 1, Institute of Physics Publishing, 2020, ISSN: 17578981, (cited By 0).
Abstract | Links | BibTeX | Етикети: ee
@conference{Stefanov2020,
title = {Study of the technical and economic efficiency and the possibilities for the construction of photovoltaic power plant above the roof structures of transformer power substations 20/0,4 kV and their service areas},
author = {S B Stefanov and A P Georgiev},
editor = {Shakev Ahmed N S Nikolov V. Petrov M.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088985813\&doi=10.1088%2f1757-899X%2f878%2f1%2f012014\&partnerID=40\&md5=1ea1205e4217af8b5d69ffd6abddff64},
doi = {10.1088/1757-899X/878/1/012014},
issn = {17578981},
year = {2020},
date = {2020-01-01},
journal = {IOP Conference Series: Materials Science and Engineering},
volume = {878},
number = {1},
publisher = {Institute of Physics Publishing},
abstract = {This report examines the possibility of constructing photovoltaic systems above concrete complete transformer posts to the medium voltage distribution networks. It has been analysed what capacities could be built depending on the size of the concrete facilities and their service areas, and what would be their economic and electricity efficiency. The main results of the analyses made show that this idea is not devoid of economic and electricity logic. © 2020 IOP Publishing Ltd. All rights reserved.},
note = {cited By 0},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
This report examines the possibility of constructing photovoltaic systems above concrete complete transformer posts to the medium voltage distribution networks. It has been analysed what capacities could be built depending on the size of the concrete facilities and their service areas, and what would be their economic and electricity efficiency. The main results of the analyses made show that this idea is not devoid of economic and electricity logic. © 2020 IOP Publishing Ltd. All rights reserved.
9.
Popov, R; Paunkov, N; Rangelova, V; Georgiev, A
Study of hybrid thermal system with photovoltaic panels using virtual instruments Journal Article
In: Renewable Energy, vol. 154, pp. 1053-1064, 2020, ISSN: 09601481, (cited By 2).
Abstract | Links | BibTeX | Етикети: ee
@article{Popov20201053,
title = {Study of hybrid thermal system with photovoltaic panels using virtual instruments},
author = {R Popov and N Paunkov and V Rangelova and A Georgiev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082117517\&doi=10.1016%2fj.renene.2020.03.024\&partnerID=40\&md5=7087a9defab273b1e11a4602fbe66fed},
doi = {10.1016/j.renene.2020.03.024},
issn = {09601481},
year = {2020},
date = {2020-01-01},
journal = {Renewable Energy},
volume = {154},
pages = {1053-1064},
publisher = {Elsevier Ltd},
abstract = {In this paper, а novel set of virtual instruments has been developed and approved. It allows for providing on-line or off-line uncertainty calculations and statistical hypothesis testing. A novel instrument “Expansion card” has been developed in our laboratory. Several tests were performed to check the performance of some hybrid heating installation components. For this purpose, a hybrid solar thermal system, combined with photovoltaic panels has been designed and constructed by the authors. The system consists of two basic subsystems: thermal part and electrical part. Both are equipped with measuring devices to form a complex virtual test instrument. The aim of the tests was to characterize the energy efficiency of a low-cost PV/T panel construction and to check the proper operation of the developed virtual instrument tools. The tests showed that there was poor thermal contact between the pipe and the backside of the cell's plate. That lead to the modification of the PV/T panel's construction. It was also found that at higher temperatures, the heat exchange in the PV/T panel deteriorates and its energy output is better. So the parallel connection should be preferable for PV/T panel heat exchangers. © 2020 Elsevier Ltd},
note = {cited By 2},
keywords = {ee},
pubstate = {published},
tppubtype = {article}
}
In this paper, а novel set of virtual instruments has been developed and approved. It allows for providing on-line or off-line uncertainty calculations and statistical hypothesis testing. A novel instrument “Expansion card” has been developed in our laboratory. Several tests were performed to check the performance of some hybrid heating installation components. For this purpose, a hybrid solar thermal system, combined with photovoltaic panels has been designed and constructed by the authors. The system consists of two basic subsystems: thermal part and electrical part. Both are equipped with measuring devices to form a complex virtual test instrument. The aim of the tests was to characterize the energy efficiency of a low-cost PV/T panel construction and to check the proper operation of the developed virtual instrument tools. The tests showed that there was poor thermal contact between the pipe and the backside of the cell's plate. That lead to the modification of the PV/T panel's construction. It was also found that at higher temperatures, the heat exchange in the PV/T panel deteriorates and its energy output is better. So the parallel connection should be preferable for PV/T panel heat exchangers. © 2020 Elsevier Ltd
10.
Georgiev, N P; Raychev, R P
Study of a linear generator with permanent magnets converting sea wave energy into electricity Conference
vol. 878, no. 1, Institute of Physics Publishing, 2020, ISSN: 17578981, (cited By 0).
Abstract | Links | BibTeX | Етикети: ee
@conference{Georgiev2020,
title = {Study of a linear generator with permanent magnets converting sea wave energy into electricity},
author = {N P Georgiev and R P Raychev},
editor = {Shakev Ahmed N S Nikolov V. Petrov M.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088978330\&doi=10.1088%2f1757-899X%2f878%2f1%2f012019\&partnerID=40\&md5=740abc5e961300166b7bcf22d017ca08},
doi = {10.1088/1757-899X/878/1/012019},
issn = {17578981},
year = {2020},
date = {2020-01-01},
journal = {IOP Conference Series: Materials Science and Engineering},
volume = {878},
number = {1},
publisher = {Institute of Physics Publishing},
abstract = {This paper studies the output electrical parameters of a linear generator with permanent magnets without an iron core for three types of electrical connection of its windings. Software simulations have been performed by means of ANSYS 2019 R1 and FEMM, and experimental studies of the linear generator have been carried out. A model has been obtained, which simulates the operation of the generator under study with good level of precision. The optimal scheme of connecting the generator windings, which is suitable for practical realization, has been determined. © 2020 IOP Publishing Ltd. All rights reserved.},
note = {cited By 0},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
This paper studies the output electrical parameters of a linear generator with permanent magnets without an iron core for three types of electrical connection of its windings. Software simulations have been performed by means of ANSYS 2019 R1 and FEMM, and experimental studies of the linear generator have been carried out. A model has been obtained, which simulates the operation of the generator under study with good level of precision. The optimal scheme of connecting the generator windings, which is suitable for practical realization, has been determined. © 2020 IOP Publishing Ltd. All rights reserved.
11.
Georgiev, N P; Raychev, R P
Study of four-spring electromagnetic harvesters Conference
vol. 878, no. 1, Institute of Physics Publishing, 2020, ISSN: 17578981, (cited By 0).
Abstract | Links | BibTeX | Етикети: ee
@conference{Georgiev2020b,
title = {Study of four-spring electromagnetic harvesters},
author = {N P Georgiev and R P Raychev},
editor = {Shakev Ahmed N S Nikolov V. Petrov M.},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85088971393\&doi=10.1088%2f1757-899X%2f878%2f1%2f012018\&partnerID=40\&md5=e340f149434d0edd10eecabf2cc81613},
doi = {10.1088/1757-899X/878/1/012018},
issn = {17578981},
year = {2020},
date = {2020-01-01},
journal = {IOP Conference Series: Materials Science and Engineering},
volume = {878},
number = {1},
publisher = {Institute of Physics Publishing},
abstract = {The article considers electromagnetic harvesters, consisting of a metal plate, fixed on four springs at their lower end, and having 2 or 4 magnets. A coil is located above the magnets. Modeling by ANSYS has been done, and the horizontal deviation of the mechanical system has been obtained. With the help of FEMM, the magnetic field of the electromagnetic harvesters has been modeled and their electromotive force has been determined. Experimental studies have been performed to verify the modeling. The influence of the construction parameters on the output electric features of the studied harvesters has been considered. © 2020 IOP Publishing Ltd. All rights reserved.},
note = {cited By 0},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
The article considers electromagnetic harvesters, consisting of a metal plate, fixed on four springs at their lower end, and having 2 or 4 magnets. A coil is located above the magnets. Modeling by ANSYS has been done, and the horizontal deviation of the mechanical system has been obtained. With the help of FEMM, the magnetic field of the electromagnetic harvesters has been modeled and their electromotive force has been determined. Experimental studies have been performed to verify the modeling. The influence of the construction parameters on the output electric features of the studied harvesters has been considered. © 2020 IOP Publishing Ltd. All rights reserved.
12.
Georgiev, N; Raychev, R
Study of two- And four- spring electromagnetic harvesters Conference
Institute of Electrical and Electronics Engineers Inc., 2020, ISBN: 9781728143460, (cited By 0).
Abstract | Links | BibTeX | Етикети: ee
@conference{Georgiev2020c,
title = {Study of two- And four- spring electromagnetic harvesters},
author = {N Georgiev and R Raychev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091344219\&doi=10.1109%2fSIELA49118.2020.9167100\&partnerID=40\&md5=e5ab81ce321bbbead735f04a13c38237},
doi = {10.1109/SIELA49118.2020.9167100},
isbn = {9781728143460},
year = {2020},
date = {2020-01-01},
journal = {2020 21st International Symposium on Electrical Apparatus and Technologies, SIELA 2020 - Proceedings},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
abstract = {The paper presents a study of two- and four- spring electromagnetic harvesters, consisting of П-shaped plates with 4 magnets mounted on two or four springs, rigidly fixed at their low ends. A coil is placed between the magnets. Modeling by means of ANSYS has been performed and the horizontal deviation of the mechanical system has been obtained. The magnetic fields of the electromagnetic harvesters have been modeled by means of FEMM. Their electromotive forces (e.m.f.) and power have been defined. Experiments for validating the models have been conducted. © 2020 IEEE.},
note = {cited By 0},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
The paper presents a study of two- and four- spring electromagnetic harvesters, consisting of П-shaped plates with 4 magnets mounted on two or four springs, rigidly fixed at their low ends. A coil is placed between the magnets. Modeling by means of ANSYS has been performed and the horizontal deviation of the mechanical system has been obtained. The magnetic fields of the electromagnetic harvesters have been modeled by means of FEMM. Their electromotive forces (e.m.f.) and power have been defined. Experiments for validating the models have been conducted. © 2020 IEEE.
13.
Georgiev, N; Raychev, R
Study of a linear generator, converting sea wave energy into electricity Conference
Institute of Electrical and Electronics Engineers Inc., 2020, ISBN: 9781728143460, (cited By 0).
Abstract | Links | BibTeX | Етикети: ee
@conference{Georgiev2020d,
title = {Study of a linear generator, converting sea wave energy into electricity},
author = {N Georgiev and R Raychev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091341043\&doi=10.1109%2fSIELA49118.2020.9167118\&partnerID=40\&md5=8277d9c843273e3b08d49d1851bc6295},
doi = {10.1109/SIELA49118.2020.9167118},
isbn = {9781728143460},
year = {2020},
date = {2020-01-01},
journal = {2020 21st International Symposium on Electrical Apparatus and Technologies, SIELA 2020 - Proceedings},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
abstract = {This paper presents a study of the influence on the electrical parameters of a linear generator with permanent magnets and no iron core, exerted by the number of its windings, connected in series, the number of their turns and the dimensions of the air gap between the magnets and the windings. Program simulations with ANSYS 2019 R1 and FEMM 4.2 have been performed and experimental studies of the linear generator have been carried out. The obtained model with good accuracy simulates the operation of the studied generator. When the construction is optimized, the electrical parameters of the generator significantly improve. © 2020 IEEE.},
note = {cited By 0},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
This paper presents a study of the influence on the electrical parameters of a linear generator with permanent magnets and no iron core, exerted by the number of its windings, connected in series, the number of their turns and the dimensions of the air gap between the magnets and the windings. Program simulations with ANSYS 2019 R1 and FEMM 4.2 have been performed and experimental studies of the linear generator have been carried out. The obtained model with good accuracy simulates the operation of the studied generator. When the construction is optimized, the electrical parameters of the generator significantly improve. © 2020 IEEE.
14.
Georgiev, N; Raychev, R
Study of a coupled piezo-electromagnetic harvester Conference
Institute of Electrical and Electronics Engineers Inc., 2020, ISBN: 9781728143460, (cited By 0).
Abstract | Links | BibTeX | Етикети: ee
@conference{Georgiev2020e,
title = {Study of a coupled piezo-electromagnetic harvester},
author = {N Georgiev and R Raychev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091335801\&doi=10.1109%2fSIELA49118.2020.9167094\&partnerID=40\&md5=601b88f1cac01603f1de951e46a2c80a},
doi = {10.1109/SIELA49118.2020.9167094},
isbn = {9781728143460},
year = {2020},
date = {2020-01-01},
journal = {2020 21st International Symposium on Electrical Apparatus and Technologies, SIELA 2020 - Proceedings},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
abstract = {The paper presents a study of a coupled piezoelectromagnetic harvester, consisting of a piezo-harvester and an attached to it electromagnetic harvester. Modeling in ANSYS has been performed, by means of which the horizontal deviation of the mechanical system has been obtained and the accumulated charge on the electrodes of the piezo-harvester has been calculated. The magnetic field of the electromagnetic harvester has been modeled with the help of FEMM and its electromotive force (e.m.f.) has been defined. Equivalent circuits have been drawn and experiments for validation of the developed models have been conducted. © 2020 IEEE.},
note = {cited By 0},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
The paper presents a study of a coupled piezoelectromagnetic harvester, consisting of a piezo-harvester and an attached to it electromagnetic harvester. Modeling in ANSYS has been performed, by means of which the horizontal deviation of the mechanical system has been obtained and the accumulated charge on the electrodes of the piezo-harvester has been calculated. The magnetic field of the electromagnetic harvester has been modeled with the help of FEMM and its electromotive force (e.m.f.) has been defined. Equivalent circuits have been drawn and experiments for validation of the developed models have been conducted. © 2020 IEEE.
15.
Hadzhiev, I; Malamov, D; Balabozov, I; Yatchev, I
Institute of Electrical and Electronics Engineers Inc., 2020, ISBN: 9781728143460, (cited By 0).
Abstract | Links | BibTeX | Етикети: ee
@conference{Hadzhiev2020b,
title = {Study of operational parameters of a capacitor bank with detuned reactor for power factor correction in a low voltage network},
author = {I Hadzhiev and D Malamov and I Balabozov and I Yatchev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091335433\&doi=10.1109%2fSIELA49118.2020.9167141\&partnerID=40\&md5=1defa7590a62d53c66b437f1d411fbb5},
doi = {10.1109/SIELA49118.2020.9167141},
isbn = {9781728143460},
year = {2020},
date = {2020-01-01},
journal = {2020 21st International Symposium on Electrical Apparatus and Technologies, SIELA 2020 - Proceedings},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
abstract = {The paper presents the results from a study of a capacitor bank with detuned reactor for power factor correction in a three-phase low voltage network. The effect of the high harmonics in the network, as well as the influence of the inductance of the detuned reactor on the operational parameters of the three-phase capacitor bank have been studied by means of a computer model, synthesized in Matlab/Simulink. The parameters of the network have been taken into account. The studies have been performed at the following values of capacitive power of the capacitor bank: 10kVAr, 30kVAr, 50kVAr and 60kVAr. Conclusions have been made and recommendations given concerning the choice of a detuned reactor for power factor correction devices. © 2020 IEEE.},
note = {cited By 0},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
The paper presents the results from a study of a capacitor bank with detuned reactor for power factor correction in a three-phase low voltage network. The effect of the high harmonics in the network, as well as the influence of the inductance of the detuned reactor on the operational parameters of the three-phase capacitor bank have been studied by means of a computer model, synthesized in Matlab/Simulink. The parameters of the network have been taken into account. The studies have been performed at the following values of capacitive power of the capacitor bank: 10kVAr, 30kVAr, 50kVAr and 60kVAr. Conclusions have been made and recommendations given concerning the choice of a detuned reactor for power factor correction devices. © 2020 IEEE.
16.
Balabozov, I; Tomov, D; Yatchev, I; Hadzhiev, I; Brauer, H
Institute of Electrical and Electronics Engineers Inc., 2020, ISBN: 9781728143460, (cited By 1).
Abstract | Links | BibTeX | Етикети: ee
@conference{Balabozov2020,
title = {Experimental study of the influence of some parameters on the characteristics of hybrid electromagnetic system with magnetic flux modulation},
author = {I Balabozov and D Tomov and I Yatchev and I Hadzhiev and H Brauer},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85091340158\&doi=10.1109%2fSIELA49118.2020.9167093\&partnerID=40\&md5=d6ea773ae39188b7376d75d8048c11a2},
doi = {10.1109/SIELA49118.2020.9167093},
isbn = {9781728143460},
year = {2020},
date = {2020-01-01},
journal = {2020 21st International Symposium on Electrical Apparatus and Technologies, SIELA 2020 - Proceedings},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
abstract = {Experimental study of a prototype of hybrid electromagnetic system with magnetic flux modulation is carried out with specially assembled control and measurement circuits. Also, software algorithm and computer graphical interface for controlling of the system and for visualisation of the achieved results have been developed. Results are obtained for the current through the coils and for the changes of the magnetic flux. Two different measurement sensors are used in order to verify the accuracy of the results for the current through the coils, © 2020 IEEE.},
note = {cited By 1},
keywords = {ee},
pubstate = {published},
tppubtype = {conference}
}
Experimental study of a prototype of hybrid electromagnetic system with magnetic flux modulation is carried out with specially assembled control and measurement circuits. Also, software algorithm and computer graphical interface for controlling of the system and for visualisation of the achieved results have been developed. Results are obtained for the current through the coils and for the changes of the magnetic flux. Two different measurement sensors are used in order to verify the accuracy of the results for the current through the coils, © 2020 IEEE.
17.
Malamov, D; Hadzhiev, I; Zlatanova, V; Terzieva, S; Georgiev, A
Analysis of a wind farm with SCIG integrated into a high power system Journal Article
In: COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 39, no. 3, pp. 637-645, 2020, ISSN: 03321649, (cited By 0).
Abstract | Links | BibTeX | Етикети: ee
@article{Malamov2020637,
title = {Analysis of a wind farm with SCIG integrated into a high power system},
author = {D Malamov and I Hadzhiev and V Zlatanova and S Terzieva and A Georgiev},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85082410859\&doi=10.1108%2fCOMPEL-10-2019-0383\&partnerID=40\&md5=a13e5bb044ea5694729ee9dbc38ea4f8},
doi = {10.1108/COMPEL-10-2019-0383},
issn = {03321649},
year = {2020},
date = {2020-01-01},
journal = {COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering},
volume = {39},
number = {3},
pages = {637-645},
publisher = {Emerald Group Publishing Ltd.},
abstract = {Purpose: The aim of this paper is a steady-state analysis of the basic electrical characteristics of a wind farm with squirrel-cage induction generators (SCIG), integrated into a high power system. The SCIG are connected to the system by means of a step-up substation 21/115 kV, realized by cable lines. Design/methodology/approach: The analyses have been done with the help of a computer model, developed in MATLAB/Simulink. Findings: Results have been obtained, concerning the influence of the SCIG on the active and reactive power, on the power factor and the voltage deviation in the cases of only one generator operating, all generators operating and disabled generators. Practical implications: The analysis has been carried out for an operating wind farm in the power system. The obtained results are applicable for optimizing and managing the modes of operation of the wind farm. Originality/value: A mathematical model for studying the electrical parameters of an SCIG integrated into a high power system has been described. A computer model in MATLAB/Simulink has been synthesized. Numerical results have been obtained, concerning the dependence of the active power, the reactive power, the power factor and the voltage deviation on the shaft torque of the wind farms with SCIG. © 2020, Emerald Publishing Limited.},
note = {cited By 0},
keywords = {ee},
pubstate = {published},
tppubtype = {article}
}
Purpose: The aim of this paper is a steady-state analysis of the basic electrical characteristics of a wind farm with squirrel-cage induction generators (SCIG), integrated into a high power system. The SCIG are connected to the system by means of a step-up substation 21/115 kV, realized by cable lines. Design/methodology/approach: The analyses have been done with the help of a computer model, developed in MATLAB/Simulink. Findings: Results have been obtained, concerning the influence of the SCIG on the active and reactive power, on the power factor and the voltage deviation in the cases of only one generator operating, all generators operating and disabled generators. Practical implications: The analysis has been carried out for an operating wind farm in the power system. The obtained results are applicable for optimizing and managing the modes of operation of the wind farm. Originality/value: A mathematical model for studying the electrical parameters of an SCIG integrated into a high power system has been described. A computer model in MATLAB/Simulink has been synthesized. Numerical results have been obtained, concerning the dependence of the active power, the reactive power, the power factor and the voltage deviation on the shaft torque of the wind farms with SCIG. © 2020, Emerald Publishing Limited.
18.
Ivanov, S C; Ivanova, Y N
Reducing Energy Losses in Realising MOSFET Control by an Active du/dt Feedback Driver Conference
Institute of Electrical and Electronics Engineers Inc., 2020, ISBN: 9781728103624, (cited By 0).
Abstract | Links | BibTeX | Етикети: e, ee
@conference{Ivanov2020b,
title = {Reducing Energy Losses in Realising MOSFET Control by an Active du/dt Feedback Driver},
author = {S C Ivanov and Y N Ivanova},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099539049\&doi=10.1109%2fEEAE49144.2020.9279094\&partnerID=40\&md5=25bd0f89a2349680c3101fea86e033bc},
doi = {10.1109/EEAE49144.2020.9279094},
isbn = {9781728103624},
year = {2020},
date = {2020-01-01},
journal = {2020 7th International Conference on Energy Efficiency and Agricultural Engineering, EE and AE 2020 - Proceedings},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
abstract = {The paper presents a method and a device for active control of power transistors, operating in a switch mode. The achieved goals are related to reduction of the dynamic energy losses when controlling the key elements. The driver circuitry limits the electromagnetic radiation, eliminates the need of using RC protection groups and increases the operational reliability of power transistors. An analytical model of the studied driver scheme has been made and results from the conducted experimental studies during the MOSFET control have been given. A comparison with a commonly used driver scheme has been drawn up. © 2020 IEEE.},
note = {cited By 0},
keywords = {e, ee},
pubstate = {published},
tppubtype = {conference}
}
The paper presents a method and a device for active control of power transistors, operating in a switch mode. The achieved goals are related to reduction of the dynamic energy losses when controlling the key elements. The driver circuitry limits the electromagnetic radiation, eliminates the need of using RC protection groups and increases the operational reliability of power transistors. An analytical model of the studied driver scheme has been made and results from the conducted experimental studies during the MOSFET control have been given. A comparison with a commonly used driver scheme has been drawn up. © 2020 IEEE.
19.
Ivanova, Y; Ivanov, S; Vasileva, E; Nyagolov, D
Control of impulse converter with reverse energy transmission with active driver circuit Conference
Institute of Electrical and Electronics Engineers Inc., 2020, ISBN: 9781728175317, (cited By 0).
Abstract | Links | BibTeX | Етикети: e, ee
@conference{Ivanova2020b,
title = {Control of impulse converter with reverse energy transmission with active driver circuit},
author = {Y Ivanova and S Ivanov and E Vasileva and D Nyagolov},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099883323\&doi=10.1109%2fELECTRONICA50406.2020.9305097\&partnerID=40\&md5=57dadb2206fb3d6dc10bce3cb678c6b8},
doi = {10.1109/ELECTRONICA50406.2020.9305097},
isbn = {9781728175317},
year = {2020},
date = {2020-01-01},
journal = {11th National Conference with International Participation, ELECTRONICA 2020 - Proceedings},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
abstract = {This paper presents research of an active driver circuit with dv/dt feedback, included in the control system of a converter with reverse power transmission. A comparative analysis of the transients in the power circuit when controlling the power transistor with conventional and active driver is made. The impact of the active driver circuit on the frequency and attenuation of the resonant processes during the switching of the power transistor has been researched. Conclusions are made about the power losses, the amplitude values of the voltages and the electromagnetic radiation of the converter. © 2020 IEEE.},
note = {cited By 0},
keywords = {e, ee},
pubstate = {published},
tppubtype = {conference}
}
This paper presents research of an active driver circuit with dv/dt feedback, included in the control system of a converter with reverse power transmission. A comparative analysis of the transients in the power circuit when controlling the power transistor with conventional and active driver is made. The impact of the active driver circuit on the frequency and attenuation of the resonant processes during the switching of the power transistor has been researched. Conclusions are made about the power losses, the amplitude values of the voltages and the electromagnetic radiation of the converter. © 2020 IEEE.
20.
Ivanov, S. C.; Ivanova, Y. N.
Research of the Impact of the Active Driver Circuit with a dv/dt Feedback on the Speed of a DC Motor Conference
Institute of Electrical and Electronics Engineers Inc., 2020, ISBN: 9781728103624, (cited By 0).
Abstract | Links | BibTeX | Етикети: e, ee
@conference{Ivanov2020,
title = {Research of the Impact of the Active Driver Circuit with a dv/dt Feedback on the Speed of a DC Motor},
author = {S. C. Ivanov and Y. N. Ivanova},
url = {https://www.scopus.com/inward/record.uri?eid=2-s2.0-85099549013\&doi=10.1109%2fEEAE49144.2020.9279016\&partnerID=40\&md5=e81f11c93647e6f7160d8d48c169695f},
doi = {10.1109/EEAE49144.2020.9279016},
isbn = {9781728103624},
year = {2020},
date = {2020-01-01},
urldate = {2020-01-01},
journal = {2020 7th International Conference on Energy Efficiency and Agricultural Engineering, EE and AE 2020 - Proceedings},
publisher = {Institute of Electrical and Electronics Engineers Inc.},
abstract = {The main purpose of the present paper is to study the influence of an active driver with a feedback on the voltage derivative on both the speed and the average current value when performing pulse control of a DC motor. Studies with a conventional driver have also been carried out. A comparative analysis of the obtained experimental results has been made. An analysis of the harmonic composition of the voltage applied to the motor armature when controlling the motor by both the active and the conventional driver has been made. The change in the rotational speed of the motor, as well as in the average value of the current through the armature winding as a function of the pulse duty cycle has been studied experimentally. For comparison between the two drivers, oscillograms and results in tabular form are presented. © 2020 IEEE.},
note = {cited By 0},
keywords = {e, ee},
pubstate = {published},
tppubtype = {conference}
}
The main purpose of the present paper is to study the influence of an active driver with a feedback on the voltage derivative on both the speed and the average current value when performing pulse control of a DC motor. Studies with a conventional driver have also been carried out. A comparative analysis of the obtained experimental results has been made. An analysis of the harmonic composition of the voltage applied to the motor armature when controlling the motor by both the active and the conventional driver has been made. The change in the rotational speed of the motor, as well as in the average value of the current through the armature winding as a function of the pulse duty cycle has been studied experimentally. For comparison between the two drivers, oscillograms and results in tabular form are presented. © 2020 IEEE.