DK156353B - ENGINE WITH CONTROLLED MAGNETIC FLUID DENSITY - Google Patents

Description

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DK 156353 BDK 156353 B

Den foreliggende opfindelse angâr en motor med kontrolleret drej-ningsmoment af den i US-patentskrift 4.063.135 angivne art.The present invention relates to a controlled torque motor of the kind disclosed in U.S. Patent 4,063,135.

I den nævnte US-patentskrift 4.063.135 beskrives en elektromotor/ som har en betydelig bedre virkningsgrad end de hidtil almindelige. I 5 hovedtrækkene virker motoren ved tilvejebringelse af et System, i hvil-ket den magnetiske fluxtæthed i statoren holdes pâ et xnaksimalt niveau, medens str0mmen i rotoren ogsâ holdes pâ en h0j vserdi under fuld be-lastning. Fluxtætheden i statoren reguleres ved hjælp af en kondensa-tor, som er forbundet i sérié med hovedstatorviklingen, og som har en 10 sâdan værdi, at den deri lagrede spænding i forbindelse med indgangs-spændingen bevirker periodisk overskridelse af statorkernens mætnings-flux med det résultat, at kernen periodisk skifter ikke-lineært fra en umættet til en mættet tilstand og tilbage igen. Kondensatoren virker til begrænsning af den mængde energi, som kan overf0res til rotoren, 15 selv nâr rotoren har meget lav impedans, med det résultat at rotor-str0mmen ogsâ kan holdes pâ en maksimal værdi. Fortrinsvis er en hjælpevikling forbundet i parallel med hovedviklingen og kondensatoren til tilvejebringelse af det njJdvendige drejefelt til igangsætning af en enfasemotor og desuden til tilvejebringelse af et betydeligt st0rre 20 igangsætningsmoment af motoren.The aforementioned U.S. Patent 4,063,135 discloses an electric motor / which has a significantly better efficiency than the previous ones. In the 5 main features, the motor operates by providing a System in which the magnetic flux density in the stator is kept at a maximum level, while the current in the rotor is also maintained at a high value under full load. The flux density in the stator is controlled by means of a capacitor connected in series with the main stator winding and having such a value that the voltage stored therein in connection with the input voltage causes periodic excess of the saturation flux of the stator core with the result. , that the kernel periodically shifts nonlinearly from an unsaturated to a saturated state and back again. The capacitor acts to limit the amount of energy that can be transferred to the rotor, even when the rotor has very low impedance, with the result that the rotor current can also be kept at a maximum value. Preferably, an auxiliary winding is connected in parallel with the main winding and the capacitor to provide the necessary turning field for starting a single-phase motor and, moreover, for providing a substantially greater starting torque of the motor.

Selv om motoren har vist sig at være yderst tilfredsstillende, har det vist sig, at der kan opnâs endnu h0jere virkningsgrader, hvis der med en vikling frembringes en formagnetisering, som varierer den effek-tive mængde af magnetisk materiale, som er disponibelt for motorens ho-25 vedvikling, i overensstemmelse med netbetingelserne, bêlastningsbetin-gelserne eller andre 0nskede betingelser. Ved variering af den effective mængde magnetisk materiale, som er disponibel, kan statorens magnetiske tab og kobbertab, som udg0r en betydelig og ukontrollerbar del af det samlede tab i en kendt motor, bringes til at variere i afhængig-30 hed af motorbelastningen. Med andre ord, hvis motoren if01ge den foreliggende opfindelse I0ber i tomgang, g0res den effektivt disponible mængde magnetisk materiale meget lille, sâ at statorens magnetiske tab og kobbertab er yderst smâ. Det effektivt disponible magnetiske materiale er imidlertid tilstrækkeligt til frembringelse af forn0den kraft 35 til drift af motoren i tomgang. Nâr motorens belastes, for0ges raængden - 2 -Although the motor has been found to be highly satisfactory, it has been found that even higher efficiencies can be obtained if a winding produces a magnetization which varies the effective amount of magnetic material available to the motor's head. -25 winding, in accordance with the grid conditions, loading conditions or other desired conditions. By varying the effective amount of magnetic material available, the stator's magnetic loss and copper loss, which constitute a significant and uncontrollable portion of the total loss in a known motor, can be caused to vary depending on the motor load. In other words, if the motor according to the present invention is idling, the effective amount of magnetic material available is made very small, so that the stator's magnetic loss and copper loss are extremely small. However, the efficiently available magnetic material is sufficient to produce the required force 35 to operate the engine at idle. When the engine is loaded, the amount increases - 2 -

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af disponibelt magnetisk materiale sâ meget, at der stadig frerabringes tilstrækkelig energi. Naturligvis for0ges motorens indre tab under den-ne bêlastningsperiode, men kan stadigvæk være mindre end det ville være tilfældet, hvis motoren var under fuld bêlastning. Da tabene bringes 5 til at variere med motorbelastningen, og da en motor sjældent drives under fuld belastning hele tiden, formindskes de gennemsnitlige indre tab betydeligt, og virkningsgraden for0ges. Resultatet er en motor, som er fuldt tilfredsstillende under aile belastningsbetingelser, men som forbruger betydelig mindre elektrisk energi end kendte motorer, som har 10 hovedsagelig samme tab, hvad enten de 10ber i tomgang eller ved fuld belastning.of available magnetic material to such an extent that sufficient energy is still generated. Of course, the engine's internal loss is increased during this load period, but may still be less than would be the case if the engine was under full load. Since the losses are caused to vary with the motor load and since a motor is rarely operated under full load all the time, the average internal losses are significantly reduced and the efficiency is increased. The result is a motor that is fully satisfactory under all load conditions, but which consumes significantly less electrical energy than known motors, which have 10 essentially the same losses, either at idle or full load.

Reguleringen af den effektivt disponible maangde magnetisk materiale i motoren opnâs if01ge opfindelsen ved at udforme elektromotoren af den i indledningen til krav 1 angivne art sâledes, som det er angivet i 15 kravets kendetegnende del. Herved opnâs, at styreviklingen, nâr den er str0mf0rende, bevirker delvis mætning af statorkernen, hvilket medf0rer formindsket permeabilitet, der vil hâve samme virkning som hvis stator-kernens raagnetiske tværsnitsareal var blevet formindsket.Denne reduk-tion af det magnetiske tværsnitsareal formindsker kernens permeabilitet 20 med det résultat, at spændingen over motoren ligeledes reduceres. Der-ved formindskes ogsâ spændingen over kondensatoren, da str0mmen til en-hver tid mâ være en sâdan, at aile spændinger i kredsl0bet tilsammen bliver nul. For mindskelsen af kondensatorspændingen medf0rer en til-svarende formindskelse af den i kondensatoren oplagrede energi som f01-25 ge af ligningen:The regulation of the efficiently available amount of magnetic material in the motor is achieved according to the invention by designing the electric motor of the kind specified in the preamble of claim 1 as stated in the characterizing part of the claim. This results in the fact that the control winding, when live, causes partial saturation of the stator core, resulting in diminished permeability which would have the same effect as if the static cross-sectional area of the stator core had been reduced.This reduction of the magnetic cross sectional area of the stator core. with the result that the voltage across the motor is also reduced. This also reduces the voltage across the capacitor, since the current must at all times be such that all the voltages in the circuit together become zero. For the reduction of the capacitor voltage, a corresponding decrease in the energy stored in the capacitor results as a factor of 25-25 of the equation:

, 2 E = J5CV, 2 E = J5CV

hvor E = den oplagrede energi, 30 C = kondensatorens kapacitet, og V = kondensatorens spænding.where E = the stored energy, 30 C = capacitor capacity, and V = capacitor voltage.

Den energi, som nu 10ber i motoren under hver halvperiode, er stærkt formindsket, og motortabene formindskes tilsvarende.The energy that now exits in the engine during each half-period is greatly reduced and the engine losses are reduced accordingly.

35 . Hvis str0mmen i styreviklingen g0res til en funktion af en motor- - 3 -35. If the current in the control winding is made to function of a motor - 3 -

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tilstand, fx. belastningstilstanden, kan motoren bringes til at arbejde ved et meget effektivt punkt for aile belastningsbetingelser. Hvis sâ-ledes motoren ikke er belastet, kan styrestr0mmen g0res h0j med det résultat, at kernens effektive tværsnitsareal er lille, sâ at den cirku-5 lerende energi og de tilsvarende tab ligeledes er smà. Efterhânden som belastningen tiltager, kan styrestr0mmen bringes til at aftage med det résultat, at motorens energiomsætningsevne forages til det forn0dne niveau til drift af den for0gede belastning. Styrestr0mmen kan naturlig-vis g0res afhængig af andre motorbetingelser, som fx. netspænding eller 10 hastighed eller en hvilken som helst 0nsket kombination af motorbetingelser eller andre 0nskede ydre betingelser.condition, e.g. the load condition, the engine can be made to operate at a very effective point for all load conditions. If the motor is not loaded, the control current can be made high with the result that the effective cross-sectional area of the core is small, so that the circulating energy and the corresponding losses are also small. As the load increases, the control current can be reduced with the result that the engine's energy conversion capacity is reduced to the required level to operate the increased load. The control current can of course be made dependent on other engine conditions, e.g. mains voltage or speed or any desired combination of motor conditions or other desired external conditions.

Den foreliggende opfindelse har derfor til formai at tilvejebringe en elektromotor, som arbejder meget effektivt.Therefore, the present invention aims to provide an electric motor which operates very efficiently.

Et andet formâl for opfindelsen er at tilvejebringe en elektromo-15 tor, ved hvilken den overf0rte energi og dermed de indre tab bringes til at variere i afhængighed af de til motoren stillede krav.Another object of the invention is to provide an electromotor by which the transferred energy and thus the internal losses are caused to vary according to the requirements of the motor.

Opfindelsen er nasrmere forklaret i det f01gende under henvisning til tegningen, pâ hvilken 20 fig. 1 viser et koblingsdiagram for en forenklet udf0relse af motoren if01ge opfindelsen, fig. 2 et koblingsdiagram for en anden udf0relsesform, fig. 3 et koblingsdiagram for en yderligere udf0relsesform, fig. 4 et koblingsdiagram for endnu en udf0relsesform, ved 25 hvilken systemet virker i afhængighed af motorens omdrejningstal, og fig. 5 et koblingsdiagram for en udf0relsesform, ved hvilket systemet virker i afhængighed af ændringer i netstr0mmen.BRIEF DESCRIPTION OF THE DRAWINGS The invention is explained in more detail below with reference to the drawing, in which: FIG. 1 shows a circuit diagram for a simplified embodiment of the motor according to the invention; FIG. 2 is a circuit diagram of another embodiment; FIG. 3 is a circuit diagram of a further embodiment; FIG. 4 shows a circuit diagram for yet another embodiment, in which the system operates in dependence on the engine speed, and FIG. 5 is a circuit diagram of an embodiment in which the system operates in response to changes in the mains current.

3030

Fig. 1 viser i skematisk form en forenklet udf0relsesform for den foreliggende opfindelse. 10 betegner en vekselstr0minduktionsmotor med kortslutningsrotor. Motoren har en stator 12 af magnetisk materiale og en kortslutningsrotor 14. Statoren er vist udf0rt med fire polben 16, 35 18, 20 og 22, men det ville forstâs, at der ogsâ kan være anbragt flereFIG. 1 is a schematic representation of a simplified embodiment of the present invention. 10 represents a short-circuit alternating current induction motor. The motor has a stator 12 of magnetic material and a short-circuit rotor 14. The stator is shown to be constructed with four poles 16, 35 18, 20 and 22, but it will be understood that several may also be arranged

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- 4 - eller færre polben. Det vil ogsâ forstâs, at den viste form af polstyk-kerne kun er skematisk. Der er ikke gjort noget fors0g pâ at gengive den optimale fysiske udformning af motoren·- 4 - or fewer pole legs. It will also be understood that the shape of the pole pieces shown is only schematic. No attempt has been made to reproduce the optimum physical design of the engine ·

Motorens statorvikling 24 er viklet pâ polerne 16 og 20 og er for-5 bundet med indgangsklemmer 26 over en seriekondensator 28. Kondensato-ren beh0ver ikke at hâve nogen bestemt værdi, men dens kapacitet mâ være stor nok til opretholdelse af en kapacitiv effektfaktor i serie-forbindelsen af kondensatoren og viklingen 24 under motorens normale drift. Pâ polbenene 18 og 22 er viklet en hjælpevikling 30, som er for-10 bundet i parallel med viklingen 24 og kondensatoren 28. Viklingen 30 har fortrinsvis betydelig st0rre selvinduktion og impedans end viklingen 24. Den kan fx. hâve betydelig flere vindinger af tyndere trâd. Kondensatoren 28 er shuntet med en startkondensator 32 ved hjælp af en centrifugalafbryder 34.The motor stator winding 24 is wound on poles 16 and 20 and is connected to input terminals 26 over a series capacitor 28. The capacitor need not have any definite value, but its capacity must be large enough to maintain a capacitive power factor in series -connection of the capacitor and winding 24 during normal operation of the motor. On the pole legs 18 and 22 there is wound an auxiliary winding 30 which is connected in parallel with the winding 24 and the capacitor 28. The winding 30 preferably has considerably greater self-induction and impedance than the winding 24. It can, for example. have significantly more windings of thinner strands. Capacitor 28 is shunted with a starting capacitor 32 by means of a centrifugal switch 34.

15 Pâ statorkemen er viklet en styrevikling 36, som kan tils luttes til en styrestr0mkilde gennem klemmer 38. Som det vil ses, er styre-viklingen 36 viklet sâledes pâ statorkernen 12, at de af motorviklin-gerne frembragt fluxe udligner hinanden med hensyn til vekselstr0ms-flux, og at der ikke frembringes nogen vekselspænding i styreviklingen 20 36. Det vil forstâs, at anbringelsen af viklingen 36*s spoler som vist i fig. 1 kun er skematisk, og at der i praksis kan anvendes en hvilken som helst egnet viklingsteknik.15 On the stator core is a control winding 36 which can be connected to a control current source through terminals 38. As can be seen, the control winding 36 is wound on the stator core 12 so that the flux produced by the motor windings equalize with respect to alternating currents. flux, and that no alternating voltage is produced in the control winding 20 36. It will be understood that the arrangement of the coils 36 * s coils as shown in FIG. 1 is only schematic and in practice any suitable winding technique may be used.

Den principielle virkemâde af den i fig. 1 viste motor er beskre-vet i det indledningsvis nævnte US-patentskrift. Nâr der tilf0res vek-25 selspænding til klemmerne 26, begynder kondensatoren 28 at oplades, og der 10ber en str0m gennem viklingen 24. Ligeledes 10ber der str0m gennem viklingen 30, faseforskudt i forhold til den hovedsagelig kapaci-tive str0m i viklingen 24, sâledes at der frembringes et drejefelt, der sætter rotoren 14 i omdrejning. Pâ dette tidspunkt frembringes en væ-30 sentlig del af drivkraften ved hjælp af viklingen 30, eftersom hoved-viklingen 24 og kondensatoren 28 ikke endnu er kommet i deres normale driftstilstand. Efterhânden som rotorens omdrejningshastighed og den reaktive elektromotoriske kraft tiltager, bliver viklingen 24's effek-tive selvinduktion en sâdan, at viklingen 24 sammen med kondensatoren 35 28 kommer i driftstilstand. Med andre ord, fluxen fra viklingen 24 gen-The principal operation of the embodiment shown in FIG. 1 is disclosed in the U.S. Patent. When alternating voltage is applied to terminals 26, capacitor 28 begins to charge, and a current flows through the winding 24. Likewise, current flows through the winding 30, phase shifted relative to the substantially capacitive current in the winding 24, so that a pivot field is produced which turns the rotor 14 in rotation. At this point, a substantial part of the driving force is generated by the winding 30, since the main winding 24 and the capacitor 28 are not yet in their normal operating state. As the rotor speed of rotation and the reactive electromotive force increase, the effective self-induction of the winding 24 becomes such that the winding 24, together with the capacitor 35 28, enters the operating state. In other words, the flux from the winding 24

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- 5 - nem det tilh0rende magnetiske materiale bliver tilstraekkelig stor til at muligg0re drift af apparatet i driftstilstanden, dvs. kondensatoren 28 vil periodisk oplades, aflades og genoplades i modsat retning, hvor-ved det til viklingen 24 h0rende magnetiske materiale skifter fra umæt-5 tet til maettet tilstand under opretholdelse af en temmelig stor gennem-snitlig fluxtæthed.- 5 - the magnetic material associated with it becomes sufficiently large to permit operation of the apparatus in the operating state, i. the capacitor 28 will periodically charge, discharge and recharge in the opposite direction, whereby the magnetic material of the winding 24 shifts from unsaturated to saturated state while maintaining a fairly high average flux density.

Viklingen 36 benyttes til regulering af det effektive tværsnits-areal af det til viklingen 24 h0rende magnetiske materiale og dermed til regulering af dette magnetiske materiales permeabilitet. Som det 10 uden videre vil kunne ses, vil der ved indf0ring af en forholdsvis stor jævnstr0m i viklingen 36 gennem klemmerne 38 frembringes en forholdsvis stor magnetisk flux i kernen 12. Denne flux har samme virkning, som hvis mængden af magnetisk materiale i kernen 12 blev fysisk formind-sket, dvs. materialets permeabilitet formindskes ligesom selvinduktio-15 nen af viklingen 24 og mængden af energi, som kan oplagres deri. Fak-tisk kippes kernen 12's hysteresesl0jfe over, og dens areal formindskes med det résultat, at viklingen 24's selvinduktion formindskes. Spændin-gen over kondensatoren 28 indstiller sig automatisk til kompensering af den lavere spænding over den nu formindskede selvinduktion af viklingen 20 24. Dette sker, fordi summen af indgangsspaendingen plus spaandingen over viklingen 24 plus spaandingen over kondensatoren 28 plus spændingsfaldet over den samlede modstand i kredsl0bet mâ være lig nul. F01gelig vil spændingen over kondensatoren ved fald i spaendingen over viklingen 24 aftage tilsvarende for at holde sl0jfesummen pâ nul. Kondensatoren tje-25 ner naturligvis ogsâ til begrænsning af str0mmen og forhindrer en over-brænding af viklingen 24. De lavere spændinger i kondensatoren og in-duktoren betyder, at der 10ber mindre energi gennem systeraet, hvilket resulterer i en lavere str0mstyrke. Som f01ge heraf formindskes stato-rens kobbertab.The winding 36 is used to control the effective cross-sectional area of the magnetic material belonging to the winding 24 and thus to control the permeability of this magnetic material. As can be readily seen, by introducing a relatively large direct current into the winding 36 through the terminals 38, a relatively large magnetic flux is produced in the core 12. This flux has the same effect as if the amount of magnetic material in the core 12 were physically diminished, ie. the permeability of the material is reduced as is the self-inductance of the winding 24 and the amount of energy which can be stored therein. In fact, the hysteresis loop of the core 12 is tilted over, and its area is reduced with the result that the self-induction of the winding 24 is reduced. The voltage across capacitor 28 automatically adjusts to compensate for the lower voltage over the now diminished self-induction of winding 20 24. This is because the sum of the input voltage plus voltage across winding 24 plus voltage across capacitor 28 plus voltage drop across the total resistance of the circuit must be equal to zero. Accordingly, when the voltage across the coil 24 decreases, the voltage across the capacitor decreases correspondingly to keep the loop sum at zero. The capacitor, of course, also serves to limit the current and prevents over-winding of the coil 24. The lower voltages in the capacitor and inductor mean that less energy is transmitted through the system, resulting in a lower current. As a result, the copper loss of the stator is reduced.

30 Den energi som kan overf0res uander drift af motoren med h0j sty- restr0m, er naturligvis fuldt tilstraakkelig til at drive motoren i tom-gang. Tabene i motoren vil være pâ et absolut minimum i denne drifts-tilstand. Nâr motoren skal drive en belastning, kan str0mmen i styre-viklingen 36 formindskes, hvorved det effektive tværsnitsareal af ker-35 nen 12's magnetiske materiale for0ges tillige med permeabiliteten og - 6 -The energy that can be transferred during operation of the motor with high control current is, of course, fully sufficient to operate the motor at idle speed. The losses in the engine will be at an absolute minimum in this operating condition. When the motor is to drive a load, the current in the control winding 36 can be reduced, thereby increasing the effective cross-sectional area of the magnetic material of the core 12 along with the permeability and - 6 -

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motorens energioverf0ringsevne. De indre tab vil kun optræde i den tid, hvor motorens effektive st0rrelse for0ges til dækning af det forjzigede behov. Motorens gennemsnitstab er âbenbart betydeligt lavere end tabene i en gængs raotor, som mâ udformes med henblik pâ maksimal kapacitet, 5 selv i tomgang, hvorfor den ogsâ har næsten maksimale tab ved dette punkt.the motor's energy transfer ability. The internal losses will only occur during the time when the effective size of the engine is increased to meet the pre-emptive needs. The engine average loss is obviously significantly lower than the losses in a conventional rotor which must be designed for maximum capacity, 5 even at idle, so it also has almost maximum losses at this point.

Som det uden videre vil forstas, kan styrestr0mmen tilf0res til klemmerne 38 pâ talrige forskellige mâder. De 0vrige figurer pâ tegnin-gen anskueligg0r forskellige mâder, pâ hvilke dette kan udf0res, selvom 10 det vil forstâs, at mange andre rauligheder ligeledes er tilfredsstil-lende.As will be readily understood, the control current can be supplied to terminals 38 in numerous different ways. The other figures in the drawings show different ways in which this can be carried out, although it will be understood that many other possibilities are also satisfactory.

Fig. 2 anskueligg0r en af de enkleste og mest effektive mâder til tilvejebringelse af en styrestr0m til viklingen 36. I denne figur er anvendt sammen henvisningsbetegnelser for samme dele som i fig. 1. Pâ 15 statorkernen er der yderligere anbragt en tilbagekoblingsvikling 40 til frembringelse af en spænding, som er proportional med den af raotoren frembragte reaktive elektromotoriske kraft. Tilbagekoblingsviklingen 40 er forbundet med styreviklingen 36 ved hjaelp af en diode 42, og hele dette kredsl0b er forbundet mellem klemskruerne 26 ved hjælp af en af-20 bryder 44, som er koblet med centrifugalafbryderen 34. Afbryderen 44 er ikke n0dvendig, men kan være gavnlig ved at udskyde virkningen af sty-rekredsl0bet, indtil motoren er kommet op i omdrejningstal efter igang-sætningen. Af denne grund er afbryderen 44 vist i âben stilling, medens afbryderen 34 er vist i lukket stilling. Nâr f0rst motoren er kommet op 25 i omdrejningstal vil afbryderen 34 naturligvis âbnes og afbryderen 44 sluttes.FIG. 2 illustrates one of the simplest and most efficient ways of providing a control current for the winding 36. In this figure, reference numerals for the same parts as in FIG. 1. On the stator core, a feedback winding 40 is further arranged to produce a voltage which is proportional to the reactive electromotive force produced by the rotor. The feedback winding 40 is connected to the control winding 36 by means of a diode 42, and this whole circuit is connected between the terminal screws 26 by means of a switch 44, which is coupled to the centrifugal switch 34. The switch 44 is not necessary, but may be beneficial. by delaying the effect of the control circuit until the engine has reached rpm after commissioning. For this reason, the switch 44 is shown in the open position, while the switch 34 is shown in the closed position. Of course, once the engine has reached 25 rpm, the switch 34 will open and the switch 44 will close.

Antages det, at raotoren 10ber med foreskrevet omdrejningstal i tomgang, vil den i viklingen 40 frembragte spænding overstige indgangs-netspændingen, hvorfor der ved hver anden halvperiode vil I0be en jævn-30 str0m i styreviklingen 36, sâ at der frembringes en magnetisk jævn-str0msflux i statorkernen. Som ovenfor nævnt, vil denne styreflux med-f0re en formindskelse af kernens permeabilitet og en tilsvarende for-mindskelse af motorens indre tab. Antages det nu, at motoren belastes delvis, vil den hâve tendens til at gâ ned i omdrejningstal, hvorved 35 den reaktive elektromotoriske kraft formindskes. Dette bevirker, at der - 7 -Assuming that the rotor 10ber at the prescribed speed at idle, the voltage produced in the winding 40 will exceed the input mains voltage, so that at every second half-period a direct current in the control winding 36 will be generated to produce a magnetic DC current flux. in the stator core. As mentioned above, this control flux will result in a decrease in core permeability and a corresponding decrease in engine internal loss. Assuming that the motor is partially loaded, it will tend to go down in rpm, thereby reducing the reactive electromotive force. This causes - 7 -

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induceres en lavere spænding i viklingen 40, sâ at str0mmen gennera di-oden 42 og viklingen 36 aftager. Den resulterende formindskelse af sty-reflux i statorkernen vil frigive mere af kernematerialet til brug for motorens hovedkredsl0b, kernens permeabilitet stiger, og den af motoren 5 overf0rte energi tiltager, sâledes at belastningen drives ved det 0n-skede oindrejningstal. Efterhânden soin belastningen for0ges til fuld be-lastning, vil styrestr0mmen aftage til nul, sâ at ait det magnetiske materiale i statorkernen er disponibelt til brug for motorens hoved-kredsl0b.a lower voltage is induced in the winding 40 so that the current generates the diode 42 and the winding 36 decreases. The resulting decrease in control reflux in the stator core will release more of the core material for use on the main circuit of the motor, the core permeability increases, and the energy transmitted by the motor 5 increases, so that the load is driven at the desired speed. As the load is increased to full load, the control current will decrease to zero so that the magnetic material in the stator core is available for use on the motor's main circuit.

10 Som. f01ge af den store forskelligartethed af motorst0rrelser og motorkonstruktioner kan der ikke angives nogle specielle paramétré for det i fig. 2 viste styrekredsl0b. Imidlertid b0r antallet af vindinger i styreviklingen for en given motor almindeligvis være et sâdant, at der fremkoramer en stabil tilbagekoblingsdrift uden svingningstilstande, 15 sâledes som det uden videre vil forstâs.10 Som. Due to the great diversity of engine sizes and engine designs, no special parameters can be specified for the one shown in FIG. 2. However, the number of turns in the control winding for a given engine should generally be such that it produces a stable feedback operation without oscillation states, as will be readily understood.

Fig. 3 viser en udf0relsesform, ved hvilken der anvendes en ens-retterbro, sâ at der f0res en udglattet jævnstr0m gennera styreviklingen 36. I denne figur er anvendt samme henvisningsbetegnelser for samme de-le som i fig. 1 og 2. Mellem indgangsklemmerne 26 er forbundet en ens-20 retterbro 46, der frembringer en spænding, som er modsat den spænding, som frembringes af en ensretterbro, der er koblet rrted udgangen fra til-bagekoblingsviklingen 40, og som omfatter dioder 48 og 50 samt et mid-terudtag 52. Om 0nskes, kan der ogsâ anvendes filterkondensatorer 54 og 56. Der er anbragt modstande 58 og 60 for at g0re ensretterbroerne le-25 dende, Hvis den i viklingen 40 inducerede spænding er lig med indgangs-spændingen, vil det ses, at der ikke 10ber nogen str0m i styreviklingen 36. Hvis imidlertid disse to spændinger ikke er i balance, vil der 10be en str0m i styreviklingen 36, sâledes at der frembringes en styreflux i statorkernen. Dette styresystem bevirker, at den i tilbagekoblingsvik-30 lingen inducerede spænding holdes lig med indgangsspændingen, uanset netspændingen eller belastningsændringer. Hvis derfor denne motor er udformet til opnâelse af denne balance ved fuld belastning, vil enhver afvigelse enten af nettilstanden eller belastningstilstanden bevirke, at der 10ber en styrestr0m i styreviklingen 36, sâ at systemet bringes 35 tilbage til balance. Hvis fx. belastningen fjernes fra motoren, vil ro- - 8 -FIG. 3 shows an embodiment in which a rectifier bridge is used so that a smoothed DC current is generated through the control winding 36. In this figure the same reference numerals are used for the same part as in fig. 1 and 2. Between the input terminals 26 is connected a rectifier bridge 46 which produces a voltage which is opposite to the voltage produced by a rectifier bridge coupled to the output of the feedback winding 40 and comprising diodes 48 and 50 and a center outlet 52. If desired, filter capacitors 54 and 56 may also be used. Resistors 58 and 60 are provided to conduct the rectifier bridges. If the voltage induced in the winding 40 is equal to the input voltage, it will be seen that there is no current in the control winding 36. If, however, these two voltages are not in balance, 10 will be a current in the control winding 36, so that a control flux is generated in the stator core. This control system causes the voltage induced in the feedback winding to be equal to the input voltage, regardless of the mains voltage or load changes. Therefore, if this motor is designed to achieve this balance at full load, any deviation from either the grid state or the load state will cause a control current in the control winding 36 to bring the system back to balance. If e.g. the load is removed from the engine, the - 8 -

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toren 10be hurtigere og derved forage tilbagekoblingsspændingen. Der 10ber sâ en str0m i styreviklingen, hvorved statorkernens perraeabilitet formindskes tillige med den af systemet overf0rte energi, sâledes at de indre tab formindskes pâ den ovenfor beskrevne mâde. Om 0nskes, kan det 5 i fig. 3 viste kredsl0b være forsynet med en diode 42 som den i fig. 2 viste. Hvis dioden er polet i retning af str0mmens for10b fra viklingen 40 til ensretterbroen 46, vil styrekredsl0bet reagere pâ ændringer i belastningen pâ samme mâde som beskrevet under henvisning til fig. 2.the torque 10be faster, thereby lowering the feedback voltage. There is a current in the control winding, thereby reducing the permeability of the stator core along with the energy transmitted by the system, so as to reduce the internal losses in the manner described above. If desired, the 5 of FIG. 3 is provided with a diode 42 such as that of FIG. 2. If the diode is poled in the direction of the current 10b from the winding 40 to the rectifier bridge 46, the control circuit will respond to changes in the load in the same manner as described with reference to FIG. 2nd

Hvis dioden pôles i den modsatte retning, vil styrekredsl0bet reagere 10 pâ ændringer i netspændingen.If the diode is polished in the opposite direction, the control circuit will respond 10 to changes in the mains voltage.

Fig. 4 viser en udf0relsesform for opfindelsen, hvor der tilf0res str0m til styreviklingen 36 ved hjælp af en styrestr0msgenerator 62, som drives af en aksel, der pâ sin side drives af rotoren 14. Systemet reagerer sâledes pâ motorens omdrejningstal, idet styrestr0mgeneratoren 15 62 er udformet til frembringelse af en str0m, som aftager med formind- skelse af motorens omdrejningstal.FIG. 4 shows an embodiment of the invention in which power is applied to the control winding 36 by means of a control current generator 62, which is driven by a shaft which is in turn driven by the rotor 14. The system thus responds to the engine speed, the control current generator 15 62 being designed to generating a current which decreases with decreasing engine rpm.

Fig. 5 viser en modifikation, der reagerer pâ ændringer i net-str0mmen. I denne udf0relsesform er styreviklingen 36 forbundet i sérié med hjælpeviklingen 30. En anden styrevikling 66, som er polet i modsat 20 retning af viklingen 36 er forbundet mellem indgangsklemmerne 26 i sérié med en str0mbegrænsningsmodstand 68. Str0mmen gennem viklingen 66 frembringer en f0rste fluxkomposant i statorkernen, medens str0mmen gennem viklingen 36 frembringer en modsat rettet anden fluxkomposant. Viklingerne er sâledes valgt, at den af viklingen 36 frembragte flux-25 komposant er den overvejende ved tomgang, og at der optræder en hoved-sagelig jævnstr0msagtig styreflux i statorkernen, sâ at kernens permea-bilitet er lav. Efterhânden som motoren belastes og begynder at falde i omdrejningstal, optager hjælpeviklingen 30 mere str0m, sâ at den af viklingen 36 frembragte fluxkomposant tiltager og den samlede styreflux 30 i kernen aftager, hvorved der kan overf0res mere energi. Nâr motor-belastningen kommer pâ pâ sin fastsatte værdi, kan de af viklingerne 36 og 66 frembragte fluxkomposanter blive lige store, sâledes at motoren opnâr sin maksimale energioverf0ringstilstand.FIG. Figure 5 shows a modification that responds to changes in grid current. In this embodiment, the control winding 36 is connected in series with the auxiliary winding 30. Another control winding 66 which is poled in the opposite direction of the winding 36 is connected between the input terminals 26 in series with a current limiting resistor 68. The current through the winding 66 produces a first flux component in the while the current through the winding 36 produces an opposite directed second flux component. The windings are chosen such that the flux-25 component produced by the winding 36 is the predominant at idle, and that a substantially direct current-like control flux occurs in the stator core, so that the core permeability is low. As the motor is loaded and starts to decrease in rpm, the auxiliary winding 30 absorbs more current, so that the flux component generated by the winding 36 decreases and the total control flux 30 in the core decreases, allowing more energy to be transferred. When the motor load reaches its set value, the flux components produced by the windings 36 and 66 can become equal, so that the motor achieves its maximum energy transfer state.

Det vil forstâs af den ovenstâende beskrivelse, at der kan anven-35 des en hvilken som helst 0nsket mâde til afledning af styrestr0mmen fra - 9 -It will be appreciated from the foregoing description that any desired means can be used to derive the control current from - 9 -

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en hvilken som helst 0nsket kilde i forbindelse med den foreliggende opfindelse. Selvom. der er beskrevet en énfaseraotor, vil det forstâs, at den foreliggende opfindelse lige sa vel kan benyttes i forbindelse med trefase- eller flerfasemotorer. Det vil ligeledes forstâs, at, selvom 5 opfindelsen er beskrevet i forbindelse med en induktionsmotor med kort-slutningsrotor, er den ikke begraanset dertil. Det vil endvidere for-stâs, at styrestr^mmen ikke beh0ver at være jævnstr0m, men ogsâ kan vaere vekselstr0m eller kan vaare pulserende med modulation osv. De viste og beskrevne kredsl0b er sâledes kun eksempler og begrænser pâ ingen 10 mâde opfindelsens omfang.any desired source in connection with the present invention. Though. When a single-phase rotor is disclosed, it will be understood that the present invention may equally well be used in connection with three-phase or multi-phase motors. It will also be understood that, although the invention is described in connection with a short-circuit rotor induction motor, it is not limited thereto. It will further be understood that the control current need not be direct current but may also be alternating current or may be pulsating with modulation, etc. The circuits shown and described are thus only examples and in no way limit the scope of the invention.

Claims (6)

1. Elektromotor med en stator (12) af magnetisk materiale og med et antal poler (16/ 18, 20, 22), en rotor (14), en pâ statoren viklet ho-vedstatorvikling (24), sorti i sérié med en kondensator (28) er forbundet med en indgang (26) til tilslutning til en vekselspændingskilde, og 5 med mindst ên pâ statoren viklet fluxstyrevikling (36), kende-t e g n e t ved, at styreviklingen (36) frembringer en styreflux i de samme fluxveje som hovedviklingen, og at den er tilsluttet en styre-str0mkilde (38, 40, 62), hvis udgangsst0rrelse er afhaengig af en given driftstilstand af motoren.1. Electric motor with a stator (12) of magnetic material and with a plurality of poles (16/18, 20, 22), a rotor (14), a main stator winding (24) wound on the stator, in series with a capacitor (28) is connected to an input (26) for connecting to an AC voltage source, and 5 with at least one flux control winding (36) wound on the stator, characterized in that the control winding (36) produces a control flux in the same flux paths as the main winding. and that it is connected to a control power source (38, 40, 62) whose output size depends on a given operating state of the motor. 2. Elektromotor if01ge krav 1, kendetegnet ved, at str0m- kilden (38, 40, 62), til hvilken fluxstyreviklingen er koblet, udg0res af en spændingsgenerator, som er indrettet til frembringelse af en spænding, som er proportional med motorens reaktive elektromotoriske kraft.2. Electric motor according to claim 1, characterized in that the current source (38, 40, 62) to which the flux control winding is coupled is constituted by a voltage generator adapted to produce a voltage which is proportional to the reactive electric motor power of the motor. . 3. Elektromotor if01ge krav 2, kendetegnet ved, at spæn- dingsgeneratoren omfatter en pâ statoren viklet tilbagekoblingsvikling (40).3. Electric motor according to claim 2, characterized in that the voltage generator comprises a feedback winding wound on the stator (40). 4. Elektromotor if01ge krav 3, kendetegnet ved, at der mellem fluxstyreviklingen (36) og tilbagekoblingsviklingen (40) er ind- 20 skudt en ensretter (42).Electric motor according to claim 3, characterized in that a rectifier (42) is inserted between the flux control winding (36) and the feedback winding (40). 5. Elektromotor if01ge krav 1, kendetegnet ved, at den med fluxstyreviklingen (36) forbundne styrestr^mkilde omfatter en i afhæn-gighed af motorens omdrejningstal virkende str0mgenerator.Electric motor according to claim 1, characterized in that the control current source connected to the flux control winding (36) comprises a current generator acting in dependence on the engine speed. 6. Elektromotor if01ge ethvert af kravene 1 - 5, kendeteg-25 net ved, at der pâ statoren (12) er viklet en yderligere fluxstyre- vikling (66) til frembringelse af en fluxstyrekomposant i modsat ret-ning af den ved den f0rste styrevikling. (36) frembragte. 30An electric motor according to any one of claims 1 to 5, characterized in that an additional flux control winding (66) is produced on the stator (12) to produce a flux control component in the opposite direction of the first control winding. . (36). 30