SI24125A - A deviceand a method for esthablishing saturation of magnetic cores of transformators - Google Patents

A deviceand a method for esthablishing saturation of magnetic cores of transformators Download PDF

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SI24125A
SI24125A SI201200202A SI201200202A SI24125A SI 24125 A SI24125 A SI 24125A SI 201200202 A SI201200202 A SI 201200202A SI 201200202 A SI201200202 A SI 201200202A SI 24125 A SI24125 A SI 24125A
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bridge
saturation
magnetic
core
measuring
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SI201200202A
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SI24125B (en
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Petrun Martin
Klopčič Beno
Dolinar Drago
Štumberger Gorazd
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Robert Bosch Gmbh
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Priority claimed from DE201310009588 external-priority patent/DE102013009588A1/en
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Publication of SI24125B publication Critical patent/SI24125B/en

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Abstract

Metoda za določanje nasičenja magnetnega jedra transformatorja temelji na merilnem mostičku s tuljavo. Na podlagi inducirane napetosti v tuljavi merilnega mostička lahko določimo stanje nasičenja jedra transformatorja. Z umerjenim mostičkom enostavno in neposredno dobimo informacijo o tem, kakšna je gostota magnetnega polja v jedru. Z merilnim mostičkom lahko merimo lokalna ali globalna nasičenja. Mostiček je zelo prilagodljiv in enostaven. Dobro deluje tudi okolici z velikim elektromagnetnim onesnaženjem.The method for determining the saturation of the magnetic core of a transformer is based on a measuring bridge with a coil. Based on the induced voltage in the measuring bridge coil, the saturation state of the transformer core can be determined. With a calibrated bridge, we can easily and directly obtain information about the density of the magnetic field in the core. Local or global saturations can be measured with a measuring bridge. The bridge is very flexible and easy. It also works well in areas with high electromagnetic pollution.

Description

NAPRAVA IN METODA ZA UGOTAVLJANJE NASIČENJA MAGNETNIH JEDER TRANSFORMATORJEVAPPARATUS AND METHOD FOR DETERMINING THE SITUATION OF MAGNETIC TRANSFORMERS

PODROČJE TEHNIKETECHNICAL FIELD

Elektrotehnika; DC-DC pretvorniki; transformatorji; jedra transformatorjevElectrical engineering; DC-DC converters; transformers; transformer cores

TEHNIČNI PROBLEMTECHNICAL PROBLEM

Tehnični problem, ki ga rešuje predmet izuma, je detekcija nasičenje magnetnih jeder transformatorjev, prednostno v DC-DC pretvornikih. Poznavalcem tega področja je znano, da nasičenje magnetnega jedra povzroča velike tokovne konice, kar lahko privede do nepravilnega delovanja, varnostnega izklopa ali celo uničenja naprave. Nadalje vzroki, ki pripomorejo k pojavu nasičenja magnetnega jedra, kot so npr. nesimetrična zgradba, variacije komponent, ipd.A technical problem solved by the object of the invention is the detection of the saturation of the magnetic cores of transformers, preferably in DC-DC converters. Those skilled in the art are aware that saturation of the magnetic core causes large current peaks, which can lead to malfunctioning, safety shutdown or even destruction of the device. Further, causes that contribute to the occurrence of magnetic core saturation, such as asymmetric structure, component variations, etc.

STANJE TEHNIKEBACKGROUND OF THE INVENTION

Pojav nasičenja magnetnih jeder je problematičen predvsem v DC-DC pretvornikih. Povzročitelji nasičenja so lahko nelinearne polprevodniške komponente in nesimetrična zgradba transformatorja [članek Gorazd]. Z ustreznim merilnikom in metodo lahko nasičenje preprečimo in zagotovimo boljše delovanje naprave ter večje izkoristke materiala. Obstoječe merilne metode in merilniki za ugotavljanje nasičenja temeljijo na:The occurrence of magnetic core saturation is problematic especially in DC-DC converters. The saturation agents can be nonlinear semiconductor components and an asymmetric transformer structure [Gorazd article]. With a suitable meter and method, saturation can be prevented and the device will be able to function better and material to be used more efficiently. Existing saturation and measurement methods are based on:

• merjenju magnetilnega toka naprave, ki v nasičenju hitro narašča (USPT 5942134) • v zračno režo vgrajenim merilnikom magnetnega pretoka, ki meri magnetno gostoto v zračni reži (USPT 6532161 B2) • meritvi sekundarnega toka in matematičnega modela transformatorja (US 2005/0140352• Measuring the magnetic flux of a fast-growing device in saturation (USPT 5942134) • An integrated magnetic flux meter measuring the magnetic density in the air gap (USPT 6532161 B2) in the air gap • Measuring the secondary current and mathematical model of the transformer (US 2005/0140352

Al) • dodatnem transverzanem navitju (US 4439822) • dodatnem jedru (US3611330)Al) • additional transverse winding (US 4439822) • additional core (US3611330)

Poznavalcem področja je znano, da so najpreprostejše metode, ki temeljijo na integriranju pritisnjene ali inducirane napetosti v jedru. Glavna pomanjkljivost teh metod je, da moramo za določitev gostote magnetnega pretoka napetost integrirati. Pri integriranju pa razni pogreški meritev, preostala napetost operacijskega ojačevalnika, motnje, ipd. privedejo do napačnega rezultata in takšne metode so v večini primerov neuporabne.Those of skill in the art will be aware that the simplest methods based on integrating pressured or induced stress in the core are the simplest. The main disadvantage of these methods is that in order to determine the magnetic flux density, the voltage must be integrated. When integrating, there are various measurement errors, residual voltage of the operational amplifier, disturbances, etc. they lead to an incorrect result and in most cases such methods are useless.

Pomanjkljivosti metod, ki temeljijo na določanju magnetilnega toka, nastanejo v splošnem zaradi odštevanja sekundarnih in primarnih tokov, kjer je razlika zelo majhna. Zaradi pogreškov merilnikov, diskretizacije signalov in možnih motenj je težko pravilno določiti magnetilni tok. Potrebni so zelo dobri merilniki.The disadvantages of methods based on magnetic flux determination are generally due to the subtraction of secondary and primary currents, where the difference is very small. Due to meter errors, signal discretization, and possible interference, it is difficult to determine the magnetic flux correctly. Very good gauges are required.

Metode z vgrajenimi senzorji magnetnega polja so drage in se slabo obnesejo pri veliki onesnaženosti okolice z motnjami. Ob nehomogenem magnetnem polju v jedru moramo prav tako vedeti točko lokalnega nasičenja.Methods with built-in magnetic field sensors are expensive and poorly handled in the event of high environmental pollution. Given the inhomogeneous magnetic field in the nucleus, we also need to know the local saturation point.

Metode na osnovi matematičnih modelov pa zahtevajo razvoj dobrega modela, ki mora biti izredno natančen. Prav tako zahtevajo veliko računsko moč in natančne merilnike. Slabost je tudi odzivnost.Methods based on mathematical models, however, require the development of a good model, which must be extremely accurate. They also require high computing power and precise meters. Responsiveness is also a disadvantage.

V splošnem je težava detekcije nasičenja težavna, saj se veličine v področju nasičenja zelo hitro spreminjajo, kar zahteva zelo gosto vzorčenje signalov ter takojšen odziv sistema za preprečevanje nasičenja.In general, the problem of saturation detection is difficult because the magnitudes in the saturation field change very quickly, which requires very dense sampling of signals and an immediate response of the saturation suppression system.

OPIS NOVE REŠITVEDESCRIPTION OF THE NEW SOLUTION

Zgoraj predstavljeni tehnični problem Naprava in metoda za ugotavljanje nasičenja magnetnih jeder transformatorjev rešuje z enostavnim ugotavljanjem nasičenja s pomočjo merilnega mostiča (101) z merilno tuljavo (102). Mostič sestoji prednostno iz magnetno dobro prevodnega in električno slabo prevodnega materiala (posledično manj vrtinčnih tokov, ki bi lahko negativno vplivali na delovanje), lahko pa tudi iz drugega materiala. Mostič je prednostno polkrožne oblike z enakomerno razporejenim navitjem po celotni dolžini mostiča (111), lahko pa tudi drugih oblik in konfiguracij, npr. (112). Oblika, velikost ter parametri mostiča in tuljave so odvisni od dimenzij transformatorja ter mesta ugotavljanja nasičenja. Pomembni parametri mostiča, ki se lahko spreminjajo glede na specifični primer, so presek mostiča Λ (121), njegova srednja dolžina /t (122) ter material mostiča, saj le ti določajo magnetno upornost mostiča po enačbi (1), kjer sta μο permeabilnost praznega prostora ter μι relativna permeabilnost materiala mostiča. Pomembni parameter merilne tuljave (102) je število ovojev Nt (123), saj vpliva na vrednost inducirane napetosti v merilni tuljavi «jt po enačbi (2), “u = d<t>, dl (2) kjer je Φι magnetni pretok skozi merilni mostič in tuljavo.The technical problem presented above The solution and method for determining the saturation of the magnetic cores of transformers is solved by simple determination of saturation by means of a measuring bridge (101) with a measuring coil (102). The bridge consists preferably of magnetically well conductive and electrically poorly conductive material (consequently fewer eddy currents which could adversely affect the operation) but also of other material. The bridge is preferably of semicircular shape with evenly spaced winding along the entire length of the bridge (111), but may also be of other shapes and configurations, e.g. (112). The shape, size and parameters of the bridge and the coil depend on the dimensions of the transformer and the location of the saturation. Important parameters of a bridge that can vary depending on the specific case are the cross-section of the bridge 121 (121), its mean length / t (122) and the material of the bridge, since these determine the magnetic resistance of the bridge according to equation (1), where μο is permeability blank space and μι relative permeability of the bridge material. An important parameter of the measuring coil (102) is the number of envelopes N t (123), since it affects the value of the induced voltage in the measuring coil «j t by equation (2),“ u = d <t>, dl (2) where Φι is magnetic flow through the measuring bridge and the coil.

Princip delovanja mostiča je razložen s pomočjo slike 2. Na sliki 2 je prikazan tipični transformator s tremi navitji za uporabo v DC-DC pretvornikih. Mostič prislonimo na jedro transformatorja (201), ki je lahko poljubne oblike in konfiguracije. Ko se jedro pod mostičem (202) približuje nasičenju, jedru začne hitro naraščati magnetna upornost. Zaradi manjše magnetne upornosti merilnega mostiča nad jedrom (203) se vedno več magnetnega pretoka (204) začne sklepati preko mostiča mimo jedra (205). Posledično začne inducirana napetost v navitjuThe principle of operation of the bridge is explained by means of Figure 2. Figure 2 shows a typical transformer with three windings for use in DC-DC converters. We attach the bridge to the transformer core (201), which can be of any shape and configuration. As the nucleus under the bridge (202) approaches saturation, the magnetic resistance increases rapidly. Due to the lower magnetic resistance of the measuring bridge above the core (203), more and more magnetic flux (204) begins to contract over the bridge past the core (205). As a result, the induced voltage in the winding starts

mostiča (206) strmo naraščati. Na podlagi hitrega naraščanja inducirane napetosti v merilni tuljavi (208) lahko sklepamo na nasičenje jedra pod merilnim mostičem.the bridge (206) rises steeply. Based on the rapid increase of the induced voltage in the measuring coil (208), we can deduce the saturation of the core under the measuring bridge.

Tipična oblika inducirane napetosti v merilni tuljavi ko zaide jedro v nasičenje, je prikazana na sliki 301. Iz odziva inducirane napetosti v navitju (301) mostiča lahko sklepamo na stanje nasičenosti v magnetnem jedru pod mostičem, ko inducirana napetost hitro naraste oz. pade. Na sliki 301 je razvidno, da se v vsaki polperiodi napajanja pojavita dve tipični konici, (310) in (311). Ko gre jedro v nasičenje, se inducirana napetost poveča in nastane napetostna konica (310), ko pa posledično preklopimo napajalno napetost pa se zaradi hitrega upada magnetnega pretoka skozi merilni mostič pojavi napetostna konica nasprotne polaritete (311). Slednja ne predstavlja stanja nasičenja. Tako dobimo dve napetostni konici, na začetku polperiode (311) ter na koncu polperiode (310). Zato za nedvoumno določitev pravilne konice in točke nasičenja potrebujemo še dodaten indikator za izbiro napetostne konice na koncu polperiode (310), ki ga lahko dobimo na več načinov, prednostno z dodatnim merilnim ovojem (210) v katerem izmerimo inducirano napetost (211), ki jo povzroča magnetni pretok v jedru. Oblika te inducirane napetosti je prikazana na (302). Z integriranjem te inducirane napetosti dobimo približen potek gostote magnetnega polja v jedru (303). Nato lahko z logičnim vezjem enostavno določimo pravilen pulz, npr. omogočimo delovanje detekcije nasičenja ko je izpolnjen pogoj (3) δΑ>θ P) in dobimo (304). Sedaj lahko enostavno določimo točko nasičenja ko je izpolnjen pogoj (3) in ko inducirana napetost (301) doseže želeno vrednost, npr. (320) ali (321). Namesto inducirane napetosti v dodatnem ovoju lahko dodaten pogoj določimo tudi kako drugače, npr. merimo pritisnjeno napetost. Pravilen pulz lahko določimo tudi na drugačne načine, kot je npr. polariteta pulza in odvod pulza v merilni tuljavi, z uporabo nevronskih mrež, ipd.A typical form of induced voltage in a measuring coil when the nucleus enters saturation is shown in Fig. 301. From the induced voltage response in the coil winding (301), we can deduce the saturation state in the magnetic core under the bridge when the induced voltage rapidly increases or decreases. it falls. Figure 301 shows that two typical peaks occur in each power half-life, (310) and (311). When the nucleus goes into saturation, the induced voltage increases and a voltage spike (310) is formed, and when the supply voltage is subsequently switched, a voltage spike of opposite polarity (311) appears due to the rapid decrease of the magnetic flux through the measuring bridge. The latter does not represent a state of saturation. Thus, two voltage peaks are obtained, at the beginning of the half-period (311) and at the end of the half-period (310). Therefore, for the unambiguous determination of the correct tip and the saturation point, we need an additional indicator to select the voltage tip at the end of the half-period (310), which can be obtained in several ways, preferably with an additional measuring envelope (210) in which to measure the induced voltage (211), which it is caused by magnetic flux in the nucleus. The form of this induced voltage is shown in (302). By integrating this induced voltage, we obtain an approximate course of the magnetic field density in the nucleus (303). We can then easily determine the correct pulse using a logic circuit, e.g. enable saturation detection to operate when condition (3) δΑ> θ P) is fulfilled and obtain (304). It is now easy to determine the saturation point when condition (3) is satisfied and when the induced voltage (301) reaches the desired value, e.g. (320) or (321). Instead of the induced voltage in the additional sheath, the additional condition can also be determined otherwise, e.g. we measure the voltage applied. The correct pulse can also be determined in other ways, such as. pulse polarity and pulse discharge in a measuring coil, using neural networks, etc.

Z umeritvijo mostiča za določene delovne pogoje (npr. za določeno pritisnjeno napetost transformatorja izmerjeni inducirani napetosti na mostiču določimo gostoto magnetnega polja v jedru), lahko jedro preklapljamo tudi med poljubnimi maksimalnimi gostotami magnetnega polja v jedru (±2?sat), npr med 331 ali med 332.By calibrating the bridge for certain operating conditions (for example, for the specified transformer pressured measured induced voltage at the bridge, determine the magnetic field density in the nucleus), the nucleus can also switch between arbitrary maximum magnetic field densities in the nucleus (± 2? Sat ), eg between 331 or between 332.

• · · ·• · · ·

V primeru homogenega magnetnega polja v jedru zadostuje en mostiček za ugotavljanje nasičenja jedra. Magnetno polje v jedru transformatorja pa je lahko tudi nehomogeno in posledično se nasičenje jedra pojavlja lokalno in celo v različnih trenutkih. Vzrok temu je lahko konstrukcijske narave (nesimetrično porazdeljena navitja transformatorja, ipd.). V tem primeru lahko za ugotavljanje nasičenj uporabimo poljubno število mostičev. Mostič lahko uporabimo tudi za iskanje mesta nasičenja.In the case of a homogeneous magnetic field in the nucleus, a single bridge is sufficient to determine the saturation of the nucleus. However, the magnetic field in the transformer core may also be inhomogeneous and as a result, the saturation of the core occurs locally and even at different times. This may be due to structural nature (asymmetrically distributed transformer windings, etc.). In this case, any number of bridges can be used to determine saturation. We can also use the bridge to find the saturation point.

Prednosti mostiča so enostavnost in prilagodljivost, saj lahko s presekom (121), dolžino mostiča (122) in ovoji merilne tuljave (123) poljubno prilagodimo mostič za določen primer. Detekcija nasičenja prav tako ni računsko zahtevna. Nasičenje lahko ugotavljamo tako v prostem teku, kot na obremenjenem transformatorju. V nasprotju z ostalimi metodami lahko ugotavljamo lokalna in globalna nasičenja jedra. Prednost je tudi ta, da z umeritvijo mostiča sami določamo točko nasičenja in imamo informacijo o tem s kako velikim nasičenjem imamo opravka.The advantages of the bridge are its simplicity and flexibility, as the cross section (121), the length of the bridge (122) and the coils of the measuring coil (123) can be adjusted to suit the specific situation. Saturation detection is also not computationally demanding. Saturation can be detected both at idle and on the transformer. Unlike other methods, local and global kernel saturation can be determined. The advantage is that by calibrating the bridge, we determine the saturation point ourselves and have information about how much saturation we have to deal with.

Claims (4)

PATENTNI ZAHTEVKIPATENT APPLICATIONS 1. Postopek za ugotavljanje nasičenja magnetnih jeder s pomočjo merilnega mostiča s tuljavo, označenega po tem, da mostič (101) prislonimo na jedro transformatorja (201), ki je lahko poljubne oblike in konfiguracije, pri čemer ko se jedro pod mostičem (202) približuje nasičenju, jedru začne hitro naraščati magnetna upornost, nadalje pri čemer se zaradi manjše magnetne upornosti merilnega mostiča nad jedrom (203) vedno več magnetnega pretoka (204) začne sklepati preko mostiča mimo jedra (205) in posledično začne inducirana napetost v navitju mostiča (206) strmo naraščati ter končno na podlagi hitrega naraščanja inducirane napetosti v merilni tuljavi (208) lahko sklepamo na nasičenje jedra pod merilnim mostičem.A method for determining the saturation of magnetic cores by means of a measuring bridge with a coil, characterized in that the bridge (101) is restrained on the transformer core (201), which can be of any shape and configuration, with the core below the bridge (202) approaching saturation, the magnetic resistivity begins to increase rapidly, and further, due to the lower magnetic resistance of the measuring bridge above the core (203), more and more magnetic flux (204) begins to conclude across the bridge past the core (205) and consequently the induced voltage in the winding of the bridge (205) begins. 206) increase steeply, and finally, based on the rapid rise of the induced voltage in the measuring coil (208), we can deduce the saturation of the nucleus under the measuring bridge. 2. Postopek po zahtevku 1, označen po tem, da se na podlagi inducirane napetosti v navitju merilnega mostiča in dodatnega kriterija določi nasičenje jedra transformatorja tako, da ko gre jedro v nasičenje, se inducirana napetost poveča in nastane napetostna konica (310) , ko pa posledično preklopimo napajalno napetost pa se zaradi hitrega upada magnetnega pretoka skozi merilni mostič pojavi napetostna konica nasprotne polaritete (311) , pri čemer slednja ne predstavlja stanja nasičenja in tako dobimo dve napetostni konici, na začetku polperiode (311) ter na koncu polperiode (310).Method according to claim 1, characterized in that the saturation of the transformer core is determined on the basis of the induced voltage in the winding of the measuring bridge and an additional criterion such that when the core goes into saturation, the induced voltage is increased and a voltage tip (310) is formed when consequently, we switch the supply voltage, and due to the rapid decrease of the magnetic flux through the measuring bridge, a voltage pole of opposite polarity (311) appears, the latter not representing the state of saturation, thus two voltage peaks are obtained, at the beginning of the half-period (311) and at the end of the half-period (310 ). 3. Naprava za ugotavljanje nasičenja magnetnih jeder s pomočjo merilnega mostiča, označena po tem, da na podlagi inducirane napetosti v navitju merilnega mostiča določi nasičenje enosmerno komponento magnetnega polja v jedru in jo s pomočjo vodenja pretvornika za generacijo pulzno širinsko modulirane napajalne napetosti primarnega navitja prednostno odpravi, lahko pa tudi prilagodi na želeno vrednost.3. A device for determining the saturation of magnetic cores by means of a measuring bridge, characterized in that, based on the induced voltage in the winding of the measuring bridge, it determines the saturation of the unidirectional component of the magnetic field in the nucleus and, by guiding the converter for generating pulse width modulated supply voltage of the primary winding can also be adjusted to the desired value. 4. Naprava po zahtevku 4, označena po tem, da mostič sestoji prednostno iz magnetno dobro prevodnega in električno slabo prevodnega materiala (posledično manj vrtinčnih tokov, ki bi lahko negativno vplivali na delovanje), nadalje, da je prednostno polkrožne • « oblike z enakomerno razporejenim navitjem po celotni dolžini mostiča (111), ter so oblika, velikost ter parametri mostiča in tuljave so odvisni od dimenzij transformatorja ter mesta ugotavljanja nasičenja, pri čemer so pomembni parametri mostiča, ki se lahko spreminjajo glede na specifični primer, so presek mostiča At (121), njegova srednja dolžina /t (122) ter material mostiča.Apparatus according to claim 4, characterized in that the bridge consists preferably of magnetically well conductive and electrically poorly conductive material (consequently less eddy currents which could adversely affect the operation), further that it is preferably semicircular the spaced windings along the entire length of the bridge (111) and the shape, size and parameters of the bridge and the coil depend on the dimensions of the transformer and the saturation point, with important bridge parameters that may vary depending on the specific case being the cross section of bridge A t (121), its mean length / t (122), and the bridge material.
SI201200202A 2012-06-14 2012-06-14 A deviceand a method for esthablishing saturation of magnetic cores of transformators SI24125B (en)

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SI201200202A SI24125B (en) 2012-06-14 2012-06-14 A deviceand a method for esthablishing saturation of magnetic cores of transformators
DE201310009587 DE102013009587A1 (en) 2012-06-14 2013-06-07 Measuring device for detecting saturation of magnetic core of transformer in direct current static converter, has measuring coil detecting induced voltage, arranged at measuring bridge and formed as winding distributed over bridge length
DE201310009588 DE102013009588A1 (en) 2012-06-14 2013-06-07 Welding transformer for use in direct current-resistance point weld system, has iron core provided with iron core segments, primary winding provided with primary winding coils, and secondary windings provided with secondary winding coils
CN201310313394.1A CN103811156B (en) 2012-06-14 2013-06-14 Transformer and the method for setting winding
CN201310310747.2A CN103777156B (en) 2012-06-14 2013-06-14 The device and method being saturated for determining the magnetic core of transformer

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SI24125B SI24125B (en) 2022-04-29

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