Beno Klopcic - Academia.edu (original) (raw)

Papers by Beno Klopcic

Sensors

Simple, low-cost methods for sensing volatile organic compounds that leave no trace and do not ha... more Simple, low-cost methods for sensing volatile organic compounds that leave no trace and do not have a detrimental effect on the environment are able to protect communities from the impacts of contaminants in water supplies. This paper reports the development of a portable, autonomous, Internet of Things (IoT) electrochemical sensor for detecting formaldehyde in tap water. The sensor is assembled from electronics, i.e., a custom-designed sensor platform and developed HCHO detection system based on Ni(OH)2–Ni nanowires (NWs) and synthetic-paper-based, screen-printed electrodes (pSPEs). The sensor platform, consisting of the IoT technology, a Wi-Fi communication system, and a miniaturized potentiostat can be easily connected to the Ni(OH)2–Ni NWs and pSPEs via a three-terminal electrode. The custom-made sensor, which has a detection capability of 0.8 µM/24 ppb, was tested for an amperometric determination of the HCHO in deionized (DI) and tap-water-based alkaline electrolytes. This pro...

V prispevku so predstavljeni rezultati dinamicne analize srednjefrekvencnega sistema za uporovno ... more V prispevku so predstavljeni rezultati dinamicne analize srednjefrekvencnega sistema za uporovno tockasto varjenje. Sistem za tockasto varjenje sestavljajo pretvornik, enofazni transformator in polnovalni usmernik na izhodu. Polnovalni usmernik je izveden z dvema diodama, ki sta prikljuceni na sekundarni navitji transformatorja. Transformator je vzbujan z napetostjo, ki jo na principu pulzno sirinske modulacije generira pretvornik. V ustaljenem stanju v nekaterih primerih prihaja do nezaželenih tokovnih konic v primarnem toku transformatorja. Z numericno analizo je bilo ugotovljeno, da so vzrok za nastanek tokovnih konic nesimetricna konstrukcija sekundarnih navitij transformatorja in neenaki karakteristiki diod v izhodnem usmerniku, kar lahko povzroca mocno elektricno nesimetricnost sistema. Nezaželeni pojav lahko odpravimo s pasivnim ukrepom, in sicer s pravilno namestitvijo skrbno izbranih diod v izhodnem usmerniku. Zaradi ucinkovitega vodnega hlajenja varilnega sistema smo predpostavili temperaturno neodvisnost parametrov izhodnega usmernika in transformatorja v delovnem obmocju.

V clanku je obravnavana poenostavljena metoda upostevanja dinamicnih histereznih izgub v modelu e... more V clanku je obravnavana poenostavljena metoda upostevanja dinamicnih histereznih izgub v modelu enofaznega transformatorja. Magnetno nelinearna karakteristika železnega jedra je upostevana v obliki tabele, vpliv histereze pa je zajet s premikanjem omenjene karakteristike v levo in desno. Poleg vpliva histereznih izgub je v modelu transformatorja upostevan tudi vpliv vrtincnih izgub. Podana je primedava izmerjenih in izracunanih tokov, in sicer tako za primer brez kot tudi z upostevanjem vrtincnih izgub.

Povzetek. V članku so predstavljene tri metode za detekcijo nasičenja železnega jedra transformat... more Povzetek. V članku so predstavljene tri metode za detekcijo nasičenja železnega jedra transformatorja. Vse tri metode so razvite na enofaznem varilnem transformatorju, uporabljenem v sistemu za uporovno točkasto varjenje z enosmernim tokom. Prva in druga metoda (metoda I in metoda II) temeljita na lastnosti, da se v področju nasičenja zmanjša naklon magnetno nelinearne karakteristike, oziroma na zmanjšanju dinamične induktivnosti, medtem ko tretja metoda (metoda III) temelji na zmanjšanju razmerja med magnetnima poljema znotraj in zunaj transformatorja pri nasičenju transformatorja.

Vacuum, 1990

linear for the low-temperature peak and nonlinear for the hightemperature one. The logarithm of t... more linear for the low-temperature peak and nonlinear for the hightemperature one. The logarithm of the reaction rate of the ethylene oligomerization changed linearly with the activation energy of the high-temperature desorption peak. It is suggcsted that only the high-temperature desorption peak measures the surface acidity of zeolite samples. The estimated heat of adsorption of ammonia resulting from the relationship between the heat of adsorption measured calorimetrically and the temperature of the desorption maximum measured by TPD 2 was 125 k J/mole. Such values of the heat of adsorption characterize the strong acidic sites in zeolites. References

Materiali in tehnologije, 2021

Mechanical resonance is the property of a mechanical system that responds to the oscillations com... more Mechanical resonance is the property of a mechanical system that responds to the oscillations coming from the outside of the observed system. The response amplitude of the system is the highest when the frequency of the oscillations matches the system's natural frequency (its resonance frequency). It is known that resonance can cause swaying motions and even catastrophic failure in improperly constructed structures. The phenomenon is known as resonance disaster. Sonic energy enters the system through excitation and is dissipated through damping. Damping can be internal (within the material) or external (mounting of an object). Six retrieved stems of hip endoprostheses were studied. For each of them sonograms were made, showing very distinctive and narrow resonance curves with one major resonance peak followed by several higher harmonic peaks. Simulation of endoprostheses standing waves was also performed resulting in the demonstration of various standing wave modes depending on the observed frequency. Results clearly show that, due to the geometry and the used material, the observed endoprostheses have very distinctive sonic resonance characteristics. The resonance is excited by the sound coming from outside (or inside) of the human body. The energy of resonance movement of the endoprosthesis is dissipated through the endoprosthesis-bone interface. A long-term exposure to the resonance oscillations might contribute to other causes of aseptic loosening of endoprostheses. Keywords: femoral part of hip endoprosthesis, vibration analysis, resonance, aseptic loosening Mehanska resonanca je lastnost sistema, ki se odziva na zvo~na nihanja, izvirajo~a iz zunanjosti opazovanega sistema. Amplituda odziva sistema je najve~ja,~e se frekvenca nihanj ujema z naravno frekvenco sistema (njegova resonan~na frekvenca). Znano je, da lahko resonanca povzro~i zvijanje sistema ali celo poru{itev pri nepravilno na~rtovanih konstrukcijah. Pojav je znan kot resonan~na katastrofa. Zvo~na energija vstopi v sistem z vzbujanjem in se disipira z du{enjem. Du{enje nihanja je lahko notranje (znotraj sistema) ali zunanje (vpetje-namestitev sistema). [tudirali smo {est stegneni~nih delov endoprotez kolka. Za vsakega od njih so bili narejeni sonogrami, ki prikazujejo zelo izrazite in ozke resonan~ne krivulje z enim glavnim resonan~nim vrhom, ki mu sledi ve~vi{je-harmonskih vrhov. Izvedena je bila tudi simulacija stoje~ih valov, ki so pokazale razli~ne na~ine stojnega valovanja in sicer glede na opazovano frekvenco. Rezultati jasno ka`ejo, da imajo endoproteze zaradi geometrije in uporabljenega materiala zelo izra`eno zvo~no resonanco. Resonanco vzbuja zvok, ki prihaja od zunaj (ali znotraj)~love{kega telesa. Energija resonan~nega gibanja endoproteze se disipira preko spoja endoproteza-kost. Stalna izpostavljenost resonan~nim nihanjem {e dodatno prispeva k asepti~nemu omajanju endoprotez. Klju~ne besede: stegneni~ni del proteze kolka, vibracijska analiza, resonanca, asepti~no popu{~anje

Przegląd Elektrotechniczny, 2011

This paper deals with the saturation in magnetic core of a multi-winding transformer which suppli... more This paper deals with the saturation in magnetic core of a multi-winding transformer which supplies nonlinear passive load. Such systems are often a part of DC-DC converters. In order to investigate the saturation phenomenon in multi-winding transformers, a laboratory transformer was build. Analysis of time responses measured during different experiments performed on the transformer was used to explain the phenomenon in the terms of physics. It represents theoretical background for prevention of magnetic core saturation in systems with multi-winding transformers. Streszczenie. W artykule rozwazono nasycenie rdzenia magnetycznego transformatora wielouzwojeniowego z nieliniowym pasywnym obciązeniem. Taki uklad wystepuje czesto w przeksztaltnikach staloprądowych. W celu przebadania zjawiska nasycenia zbudowano transformator laboratoryjny. Analizy przebiegow czasowych mierzonych podczas roznych eksperymentow pozwalaly na wyjaśnienie fizycznej natury zjawiska, co, z kolei, jest podstawą ...

Journal of Magnetism and Magnetic Materials, 2008

... The numbers of turns, the resistances and the leakage inductances of both the primary and two... more ... The numbers of turns, the resistances and the leakage inductances of both the primary and two secondary WT's windings are denoted by N 1 , N 2 and N 3 , R 1 , R 2 and R 3 , and L σ 1 , L σ 2 and L σ 3 , respectively. ... R L and L L are the resistance and inductance of the load. ...

IEEE Transactions on Magnetics, 2014

IEEE Transactions on Magnetics, 2014

ABSTRACT The proposed paper deals with a nonlinear dynamic model of a welding transformer, where ... more ABSTRACT The proposed paper deals with a nonlinear dynamic model of a welding transformer, where the effects of hysteresis losses are accounted for by the simplified method and by the inverse form of the Jiles–Atherton hysteresis model. Both models have been modified in such a way that they can be used when the magnetically nonlinear characteristic of the entire device is determined experimentally. The aforementioned characteristics are given in the form of approximation polynomials. For defining magnetically nonlinear characteristic and both the Jiles–Atherton hysteresis model and the simplified model, an optimization procedure based on the differential evolution is applied for obtaining the parameters of applied approximation polynomials. The main goal of this paper is to evaluate both discussed models regarding their suitability to be included into dynamic model of a welding transformer used in the optimization of the entire resistance spot welding system. The evaluation focuses on achieved accuracy and computational effort required to implement the discussed models.

IEEE Transactions on Magnetics, 2012

IEEE Transactions on Magnetics, 2012

IEEE Transactions on Magnetics, 2010

This paper deals with the analytically described iron core model of a midfrequency resistance spo... more This paper deals with the analytically described iron core model of a midfrequency resistance spot welding transformer. This model considers eddy currents, hysteresis, and the saturation effect in a laminated iron core. The proposed model is simple, based on parameters that can be obtained from a data sheet, and is easy to integrate into the circuit model of the transformer. It is applicable for the design of control algorithms, as well as a rough optimization of lamination thickness, air gap width, and sizing the transformer's core.

IEEE Transactions on Magnetics, 2010

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 2011

PurposeSo far the proposed analytical methods for calculation of copper losses are rather simplif... more PurposeSo far the proposed analytical methods for calculation of copper losses are rather simplified and do not include the time component in the basic partial differential equations, which describe current density distribution. Moreover, when the physical parameters of the transformer (wire dimensions) are out of the certain range, the current density distribution approaches infinity. The purpose of this paper is to offer a generally applicable analytical method. The main goal of the proposed modification of the solution to the current density is improvement of the accuracy and stability of the analytical results.Design/methodology/approachThis paper deals with the calculation of copper losses with various methods, which are based on a time‐dependent electromagnetic field. Analytical method is based on Maxwell equations and Helmholtz equation. Numerical calculation is performed with finite element method (FEM).FindingsAnalytical method is a very accurate and it gives results, which...

Proceedings of 14th International Power Electronics and Motion Control Conference EPE-PEMC 2010, 2010

ABSTRACT This paper deals with the control improvement of a middle-frequency resistance spot weld... more ABSTRACT This paper deals with the control improvement of a middle-frequency resistance spot welding system. This is achieved by a combined closed-loop control of the welding current and closed-loop control of the iron core saturation level. The proposed control assures a very short rise time of the welding current and the best possible utilization of the transformer iron core.

V prispevku so predstavljeni rezultati dinamicne analize srednjefrekvencnega sistema za uporovno ... more V prispevku so predstavljeni rezultati dinamicne analize srednjefrekvencnega sistema za uporovno tockasto varjenje. Sistem za tockasto varjenje sestavljajo pretvornik, enofazni transformator in polnovalni usmernik na izhodu. Polnovalni usmernik je izveden z dvema diodama, ki sta prikljuceni na sekundarni navitji transformatorja. Transformator je vzbujan z napetostjo, ki jo na principu pulzno sirinske modulacije generira pretvornik. V ustaljenem stanju v nekaterih primerih prihaja do nezaželenih tokovnih konic v primarnem toku transformatorja. Z numericno analizo je bilo ugotovljeno, da so vzrok za nastanek tokovnih konic nesimetricna konstrukcija sekundarnih navitij transformatorja in neenaki karakteristiki diod v izhodnem usmerniku, kar lahko povzroca mocno elektricno nesimetricnost sistema. Nezaželeni pojav lahko odpravimo s pasivnim ukrepom, in sicer s pravilno namestitvijo skrbno izbranih diod v izhodnem usmerniku. Zaradi ucinkovitega vodnega hlajenja varilnega sistema smo predp...

Przegląd Elektrotechniczny, 2012

This paper describes a tester, which is developed to detect the right connection of the stator co... more This paper describes a tester, which is developed to detect the right connection of the stator coils and direction of field rotation. The tester detects the magnetic flux density distribution in the air gap. Stator coils of synchronous machine (SM) without rotor are supplied by three-phase sinusoidal voltages. The corresponding magnetic field distribution is measured by analogue or bipolar digital Hall probes mounted on printed circuit board, which are placed near to each stator tooth. The proposed principle of testing has been proven with numerical analysis (FEM), analytical equations and experiment. Streszczenie. W artykule opisano tester dla detekcji prawidlowości polączenia uzwojenia stojana i kierunku wirowania pola. Tester bada rozklad indukcji magnetycznej w szczelinie powietrznej. Cewki stojana silnika synchronicznego zasila sie, przy usunietym wirniku, trojfazowym napieciem sinusoidalnym i dokonuje pomiaru indukcji magnetycznej czujnikami Halla. Idea tego testu zostala potw...

Przegląd Elektrotechniczny, 2011

This paper describes a thermal analysis of the half-bridge IGBT power module, which is mounted to... more This paper describes a thermal analysis of the half-bridge IGBT power module, which is mounted to the heat sink. Power dissipation of semiconductor devices gradually heats the power module up to the certain temperature. The main objective of this research is to calculate and verify the temperature rise of the system for different cases of power dissipation and forced cooling conditions. Temperature rise in the case when power dissipation achieves its maximum can be predicted. Several solutions are proposed: analytical, numerical (finite element methods) and experimental. Streszczenie. Artykul opisuje analize cieplną polmostkowych modulow mocy IGBT zamontowanych do urządzen grzejnych. Dyssypacja mocy urządzen polprzewodnikowych stopniowo nagrzewa modul mocy do pewnej temperatury. Glownym Selene tych badan jest obliczenie i weryfikacja wzrostu temperatury roznych systemow dyssypacji energii i wymuszonych warunkow chlodzenia. Wzrost temperatury w przypadku kiedy dyssypacja energii osią...

The invention relates to a semiconductor assembly (500) for connection to a transformer winding (... more The invention relates to a semiconductor assembly (500) for connection to a transformer winding (132, 133; 408, 409), in particular a welding transformer winding, wherein a particular disc-shaped semiconductor device (501) between two contact plates (502), said at least one contact plate (502 ) can be acted upon on its (the semiconductor device 501) side away with a cooling fluid. The invention further relates to a transformer assembly (100; 600), in particular welding transformer arrangement with a primary winding (132; 408) and a secondary winding (133; 409) with downstream output rectifier arrangement (604), the output rectifier assembly (604) at least one (as a rectifier assembly 500 includes) formed semiconductor device with a rectifier diode (501).

Sensors

Simple, low-cost methods for sensing volatile organic compounds that leave no trace and do not ha... more Simple, low-cost methods for sensing volatile organic compounds that leave no trace and do not have a detrimental effect on the environment are able to protect communities from the impacts of contaminants in water supplies. This paper reports the development of a portable, autonomous, Internet of Things (IoT) electrochemical sensor for detecting formaldehyde in tap water. The sensor is assembled from electronics, i.e., a custom-designed sensor platform and developed HCHO detection system based on Ni(OH)2–Ni nanowires (NWs) and synthetic-paper-based, screen-printed electrodes (pSPEs). The sensor platform, consisting of the IoT technology, a Wi-Fi communication system, and a miniaturized potentiostat can be easily connected to the Ni(OH)2–Ni NWs and pSPEs via a three-terminal electrode. The custom-made sensor, which has a detection capability of 0.8 µM/24 ppb, was tested for an amperometric determination of the HCHO in deionized (DI) and tap-water-based alkaline electrolytes. This pro...

V prispevku so predstavljeni rezultati dinamicne analize srednjefrekvencnega sistema za uporovno ... more V prispevku so predstavljeni rezultati dinamicne analize srednjefrekvencnega sistema za uporovno tockasto varjenje. Sistem za tockasto varjenje sestavljajo pretvornik, enofazni transformator in polnovalni usmernik na izhodu. Polnovalni usmernik je izveden z dvema diodama, ki sta prikljuceni na sekundarni navitji transformatorja. Transformator je vzbujan z napetostjo, ki jo na principu pulzno sirinske modulacije generira pretvornik. V ustaljenem stanju v nekaterih primerih prihaja do nezaželenih tokovnih konic v primarnem toku transformatorja. Z numericno analizo je bilo ugotovljeno, da so vzrok za nastanek tokovnih konic nesimetricna konstrukcija sekundarnih navitij transformatorja in neenaki karakteristiki diod v izhodnem usmerniku, kar lahko povzroca mocno elektricno nesimetricnost sistema. Nezaželeni pojav lahko odpravimo s pasivnim ukrepom, in sicer s pravilno namestitvijo skrbno izbranih diod v izhodnem usmerniku. Zaradi ucinkovitega vodnega hlajenja varilnega sistema smo predpostavili temperaturno neodvisnost parametrov izhodnega usmernika in transformatorja v delovnem obmocju.

V clanku je obravnavana poenostavljena metoda upostevanja dinamicnih histereznih izgub v modelu e... more V clanku je obravnavana poenostavljena metoda upostevanja dinamicnih histereznih izgub v modelu enofaznega transformatorja. Magnetno nelinearna karakteristika železnega jedra je upostevana v obliki tabele, vpliv histereze pa je zajet s premikanjem omenjene karakteristike v levo in desno. Poleg vpliva histereznih izgub je v modelu transformatorja upostevan tudi vpliv vrtincnih izgub. Podana je primedava izmerjenih in izracunanih tokov, in sicer tako za primer brez kot tudi z upostevanjem vrtincnih izgub.

Povzetek. V članku so predstavljene tri metode za detekcijo nasičenja železnega jedra transformat... more Povzetek. V članku so predstavljene tri metode za detekcijo nasičenja železnega jedra transformatorja. Vse tri metode so razvite na enofaznem varilnem transformatorju, uporabljenem v sistemu za uporovno točkasto varjenje z enosmernim tokom. Prva in druga metoda (metoda I in metoda II) temeljita na lastnosti, da se v področju nasičenja zmanjša naklon magnetno nelinearne karakteristike, oziroma na zmanjšanju dinamične induktivnosti, medtem ko tretja metoda (metoda III) temelji na zmanjšanju razmerja med magnetnima poljema znotraj in zunaj transformatorja pri nasičenju transformatorja.

Vacuum, 1990

linear for the low-temperature peak and nonlinear for the hightemperature one. The logarithm of t... more linear for the low-temperature peak and nonlinear for the hightemperature one. The logarithm of the reaction rate of the ethylene oligomerization changed linearly with the activation energy of the high-temperature desorption peak. It is suggcsted that only the high-temperature desorption peak measures the surface acidity of zeolite samples. The estimated heat of adsorption of ammonia resulting from the relationship between the heat of adsorption measured calorimetrically and the temperature of the desorption maximum measured by TPD 2 was 125 k J/mole. Such values of the heat of adsorption characterize the strong acidic sites in zeolites. References

Materiali in tehnologije, 2021

Mechanical resonance is the property of a mechanical system that responds to the oscillations com... more Mechanical resonance is the property of a mechanical system that responds to the oscillations coming from the outside of the observed system. The response amplitude of the system is the highest when the frequency of the oscillations matches the system's natural frequency (its resonance frequency). It is known that resonance can cause swaying motions and even catastrophic failure in improperly constructed structures. The phenomenon is known as resonance disaster. Sonic energy enters the system through excitation and is dissipated through damping. Damping can be internal (within the material) or external (mounting of an object). Six retrieved stems of hip endoprostheses were studied. For each of them sonograms were made, showing very distinctive and narrow resonance curves with one major resonance peak followed by several higher harmonic peaks. Simulation of endoprostheses standing waves was also performed resulting in the demonstration of various standing wave modes depending on the observed frequency. Results clearly show that, due to the geometry and the used material, the observed endoprostheses have very distinctive sonic resonance characteristics. The resonance is excited by the sound coming from outside (or inside) of the human body. The energy of resonance movement of the endoprosthesis is dissipated through the endoprosthesis-bone interface. A long-term exposure to the resonance oscillations might contribute to other causes of aseptic loosening of endoprostheses. Keywords: femoral part of hip endoprosthesis, vibration analysis, resonance, aseptic loosening Mehanska resonanca je lastnost sistema, ki se odziva na zvo~na nihanja, izvirajo~a iz zunanjosti opazovanega sistema. Amplituda odziva sistema je najve~ja,~e se frekvenca nihanj ujema z naravno frekvenco sistema (njegova resonan~na frekvenca). Znano je, da lahko resonanca povzro~i zvijanje sistema ali celo poru{itev pri nepravilno na~rtovanih konstrukcijah. Pojav je znan kot resonan~na katastrofa. Zvo~na energija vstopi v sistem z vzbujanjem in se disipira z du{enjem. Du{enje nihanja je lahko notranje (znotraj sistema) ali zunanje (vpetje-namestitev sistema). [tudirali smo {est stegneni~nih delov endoprotez kolka. Za vsakega od njih so bili narejeni sonogrami, ki prikazujejo zelo izrazite in ozke resonan~ne krivulje z enim glavnim resonan~nim vrhom, ki mu sledi ve~vi{je-harmonskih vrhov. Izvedena je bila tudi simulacija stoje~ih valov, ki so pokazale razli~ne na~ine stojnega valovanja in sicer glede na opazovano frekvenco. Rezultati jasno ka`ejo, da imajo endoproteze zaradi geometrije in uporabljenega materiala zelo izra`eno zvo~no resonanco. Resonanco vzbuja zvok, ki prihaja od zunaj (ali znotraj)~love{kega telesa. Energija resonan~nega gibanja endoproteze se disipira preko spoja endoproteza-kost. Stalna izpostavljenost resonan~nim nihanjem {e dodatno prispeva k asepti~nemu omajanju endoprotez. Klju~ne besede: stegneni~ni del proteze kolka, vibracijska analiza, resonanca, asepti~no popu{~anje

Przegląd Elektrotechniczny, 2011

This paper deals with the saturation in magnetic core of a multi-winding transformer which suppli... more This paper deals with the saturation in magnetic core of a multi-winding transformer which supplies nonlinear passive load. Such systems are often a part of DC-DC converters. In order to investigate the saturation phenomenon in multi-winding transformers, a laboratory transformer was build. Analysis of time responses measured during different experiments performed on the transformer was used to explain the phenomenon in the terms of physics. It represents theoretical background for prevention of magnetic core saturation in systems with multi-winding transformers. Streszczenie. W artykule rozwazono nasycenie rdzenia magnetycznego transformatora wielouzwojeniowego z nieliniowym pasywnym obciązeniem. Taki uklad wystepuje czesto w przeksztaltnikach staloprądowych. W celu przebadania zjawiska nasycenia zbudowano transformator laboratoryjny. Analizy przebiegow czasowych mierzonych podczas roznych eksperymentow pozwalaly na wyjaśnienie fizycznej natury zjawiska, co, z kolei, jest podstawą ...

Journal of Magnetism and Magnetic Materials, 2008

... The numbers of turns, the resistances and the leakage inductances of both the primary and two... more ... The numbers of turns, the resistances and the leakage inductances of both the primary and two secondary WT's windings are denoted by N 1 , N 2 and N 3 , R 1 , R 2 and R 3 , and L σ 1 , L σ 2 and L σ 3 , respectively. ... R L and L L are the resistance and inductance of the load. ...

IEEE Transactions on Magnetics, 2014

IEEE Transactions on Magnetics, 2014

ABSTRACT The proposed paper deals with a nonlinear dynamic model of a welding transformer, where ... more ABSTRACT The proposed paper deals with a nonlinear dynamic model of a welding transformer, where the effects of hysteresis losses are accounted for by the simplified method and by the inverse form of the Jiles–Atherton hysteresis model. Both models have been modified in such a way that they can be used when the magnetically nonlinear characteristic of the entire device is determined experimentally. The aforementioned characteristics are given in the form of approximation polynomials. For defining magnetically nonlinear characteristic and both the Jiles–Atherton hysteresis model and the simplified model, an optimization procedure based on the differential evolution is applied for obtaining the parameters of applied approximation polynomials. The main goal of this paper is to evaluate both discussed models regarding their suitability to be included into dynamic model of a welding transformer used in the optimization of the entire resistance spot welding system. The evaluation focuses on achieved accuracy and computational effort required to implement the discussed models.

IEEE Transactions on Magnetics, 2012

IEEE Transactions on Magnetics, 2012

IEEE Transactions on Magnetics, 2010

This paper deals with the analytically described iron core model of a midfrequency resistance spo... more This paper deals with the analytically described iron core model of a midfrequency resistance spot welding transformer. This model considers eddy currents, hysteresis, and the saturation effect in a laminated iron core. The proposed model is simple, based on parameters that can be obtained from a data sheet, and is easy to integrate into the circuit model of the transformer. It is applicable for the design of control algorithms, as well as a rough optimization of lamination thickness, air gap width, and sizing the transformer's core.

IEEE Transactions on Magnetics, 2010

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 2011

PurposeSo far the proposed analytical methods for calculation of copper losses are rather simplif... more PurposeSo far the proposed analytical methods for calculation of copper losses are rather simplified and do not include the time component in the basic partial differential equations, which describe current density distribution. Moreover, when the physical parameters of the transformer (wire dimensions) are out of the certain range, the current density distribution approaches infinity. The purpose of this paper is to offer a generally applicable analytical method. The main goal of the proposed modification of the solution to the current density is improvement of the accuracy and stability of the analytical results.Design/methodology/approachThis paper deals with the calculation of copper losses with various methods, which are based on a time‐dependent electromagnetic field. Analytical method is based on Maxwell equations and Helmholtz equation. Numerical calculation is performed with finite element method (FEM).FindingsAnalytical method is a very accurate and it gives results, which...

Proceedings of 14th International Power Electronics and Motion Control Conference EPE-PEMC 2010, 2010

ABSTRACT This paper deals with the control improvement of a middle-frequency resistance spot weld... more ABSTRACT This paper deals with the control improvement of a middle-frequency resistance spot welding system. This is achieved by a combined closed-loop control of the welding current and closed-loop control of the iron core saturation level. The proposed control assures a very short rise time of the welding current and the best possible utilization of the transformer iron core.

V prispevku so predstavljeni rezultati dinamicne analize srednjefrekvencnega sistema za uporovno ... more V prispevku so predstavljeni rezultati dinamicne analize srednjefrekvencnega sistema za uporovno tockasto varjenje. Sistem za tockasto varjenje sestavljajo pretvornik, enofazni transformator in polnovalni usmernik na izhodu. Polnovalni usmernik je izveden z dvema diodama, ki sta prikljuceni na sekundarni navitji transformatorja. Transformator je vzbujan z napetostjo, ki jo na principu pulzno sirinske modulacije generira pretvornik. V ustaljenem stanju v nekaterih primerih prihaja do nezaželenih tokovnih konic v primarnem toku transformatorja. Z numericno analizo je bilo ugotovljeno, da so vzrok za nastanek tokovnih konic nesimetricna konstrukcija sekundarnih navitij transformatorja in neenaki karakteristiki diod v izhodnem usmerniku, kar lahko povzroca mocno elektricno nesimetricnost sistema. Nezaželeni pojav lahko odpravimo s pasivnim ukrepom, in sicer s pravilno namestitvijo skrbno izbranih diod v izhodnem usmerniku. Zaradi ucinkovitega vodnega hlajenja varilnega sistema smo predp...

Przegląd Elektrotechniczny, 2012

This paper describes a tester, which is developed to detect the right connection of the stator co... more This paper describes a tester, which is developed to detect the right connection of the stator coils and direction of field rotation. The tester detects the magnetic flux density distribution in the air gap. Stator coils of synchronous machine (SM) without rotor are supplied by three-phase sinusoidal voltages. The corresponding magnetic field distribution is measured by analogue or bipolar digital Hall probes mounted on printed circuit board, which are placed near to each stator tooth. The proposed principle of testing has been proven with numerical analysis (FEM), analytical equations and experiment. Streszczenie. W artykule opisano tester dla detekcji prawidlowości polączenia uzwojenia stojana i kierunku wirowania pola. Tester bada rozklad indukcji magnetycznej w szczelinie powietrznej. Cewki stojana silnika synchronicznego zasila sie, przy usunietym wirniku, trojfazowym napieciem sinusoidalnym i dokonuje pomiaru indukcji magnetycznej czujnikami Halla. Idea tego testu zostala potw...

Przegląd Elektrotechniczny, 2011

This paper describes a thermal analysis of the half-bridge IGBT power module, which is mounted to... more This paper describes a thermal analysis of the half-bridge IGBT power module, which is mounted to the heat sink. Power dissipation of semiconductor devices gradually heats the power module up to the certain temperature. The main objective of this research is to calculate and verify the temperature rise of the system for different cases of power dissipation and forced cooling conditions. Temperature rise in the case when power dissipation achieves its maximum can be predicted. Several solutions are proposed: analytical, numerical (finite element methods) and experimental. Streszczenie. Artykul opisuje analize cieplną polmostkowych modulow mocy IGBT zamontowanych do urządzen grzejnych. Dyssypacja mocy urządzen polprzewodnikowych stopniowo nagrzewa modul mocy do pewnej temperatury. Glownym Selene tych badan jest obliczenie i weryfikacja wzrostu temperatury roznych systemow dyssypacji energii i wymuszonych warunkow chlodzenia. Wzrost temperatury w przypadku kiedy dyssypacja energii osią...

The invention relates to a semiconductor assembly (500) for connection to a transformer winding (... more The invention relates to a semiconductor assembly (500) for connection to a transformer winding (132, 133; 408, 409), in particular a welding transformer winding, wherein a particular disc-shaped semiconductor device (501) between two contact plates (502), said at least one contact plate (502 ) can be acted upon on its (the semiconductor device 501) side away with a cooling fluid. The invention further relates to a transformer assembly (100; 600), in particular welding transformer arrangement with a primary winding (132; 408) and a secondary winding (133; 409) with downstream output rectifier arrangement (604), the output rectifier assembly (604) at least one (as a rectifier assembly 500 includes) formed semiconductor device with a rectifier diode (501).