US2395881A - Controlled peaking trasformer - Google Patents

Description

March 5, 1946 H. KLEMPERER 2,395,831

CONTROLLED PEAKING TRANSFORMER Filed Aug. 2, 1940 4 Sheets-Sheet 1 Fuel.

VOLTAGE 0N con. 3

LEG 4. SATURATION Flux OF LEG 4/ LUX Timoueu com M108 3 0.0. BIAS S m6 ISM-URAT'ON FLUX FLUXmROUGH%/ Fk'ruam-lou lux 0F Lee 4 Con. 7 or LEG 4- I TOTAL. VOLTAGE AcRoss Cons 7 no8 INVENTOR.

HANs' KLEMPERER,

1 B SZM Q I QGBIASMILUAMPERES Y ANQULAR DISPLACEMENT Or MAGNET E TY.

SATURATION F'Lux or L56 4 Vo LTAG E o F Con. 7AM!) 5 u PEAK VOLTAGE fllLovoLTs.

March 5, 1946. KLEMPERER 2,395,881

CONTROLLED PEAKING TRANSFORMER Filed Aug. 2, 1940 4 Sheets-Sheet 2 FIG. 5.

FIG. 6b iii;

22 F'le.7.

2 Jamal: l

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March 5, 1946. H. KLEMPERER CONTROLLED PEAKING TRANSFORMER Filed Aug. 2. 1940 4 Sheets-Sheet 3 HUN 7/////// numu 'NVENTOR HANS KLEMPERER,

March 5, 1946. H. KLEMPERER CONTROLLED PEAKING TRANSFORMER Filed Aug. 2, 1940 4 Sheets-Sheet 4 FIG."

d 1"6 FIG. 12. 90 FIG. l3.

, I TOTAL VOLTAGE n f AcRoss Cows I a VOLTAGE oF 601154962 INVENTOR. HANS KLEMPERER,

Patented Mar. 5, 1946 UNITED STATES PATENT OFFICE CONTROLLED PEAKING TRANSFORMER Hans Klemperer, Belmont, Mass, assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation of Delaware Application August 2, 1940, Serial No. 349,785 (Cl. 171 119) 3 Claims.

This invention relates to controlled peaking transformers in which alternating voltages of sine wave form are converted into peaked waves of controllable magnitude. Heretofore, the control of the magnitude of the peaking output waves of such transformers has required a considerabl amount of control power.

An object of this invention is to produce a peaking transformer .in which the magnitude of the peaked output voltage may be varied through a wide range in response to a relatively small controlling factor.

Another object of this invention is to produce such variation by using small direct currents.

A still further object of this invention is to produce such variation by the use of movable magnetic means.

The foregoing and other objects of this invention will be best understood from the following description of exemplifications thereof, reference being had to the accompanying drawings wherein: I

Fig. 1 is a diagrammatic representation of a peaking transformer embodying my invention;

Figs. 2, 2a, 3, 3a, and 4 are curves representing the mode of operation of the arrangement shown in Fig. 1;

Fig. 5 is a diagrammatic representation of a modification of the arrangement shown in Fig. 1;

Figs. 6, 6a, and 6b are curves representing the mode of operation of the arrangement shown in Fig.

Fig. 7 is a diagrammatic representation of a circuit in which the embodiment illustrated in Fig. 1 may be used;

Fig. 8 is a representation of a modified form of my invention using a movablemagnetic control means;

Fig. 9 represents another embodiment of my invention in which motor driven movable magnet control means are utilized;

Fig. 10 is a top view of the device shown in Fig. 9;

Fig. 11 is a representation of a still further embodiment of my invention; and

Figs. 12, 13, and 13a ar curves illustrating the mode of operation of the embodiment shown in Fig. 11. t

The embodiment shown in Fig. 1 consists of a core member I made of suitable magnetic material such a iron. Said core is provided with a central leg 2 upon which the input winding 3 is wound. The winding 3 is adapted to be energized from some suitable source of alteinating current usually of substantially sine wave form. On one side of the central leg 2 is located a saturable leg 4 preferably made of a material of high magnetic permeability such as Permalloy steel. The saturable leg 4 is made with two side leg portions 5 and 6 upon which output coil l and 8 respectively are wound. The peaked output voltages are generated in these coils l and 8, which, in the arrangement shown in Fig. 1, are connected in series. In order to introduce saturating flux, 9, leg 9 is provided extending from between the leg portions 5 and 6 to the central portion of the central leg 2. .A coil I0 is wound upon the leg 9 and is adapted to be supplied with direct current for the purpose of introducing sufficient direct current flux into the leg portions 5 and 6 to saturate them. The leg 9 is also preferably surrounded by a short-circuited loop II which tends to keep alternating flux out of the leg 9. A pair of side legs l2 and I3 connect the outer ends of the leg portions 5 and 6 to- I the outer ends of the central leg 2 and extend beyond said central leg to a lower leg I4 which is adapted to carry the alternating current leakage flux. The lower leg I 4 is provided with an air gap I5 which introduces magnetic resistance into the magnetic circuit of which the leg I4 is a part, and also serves to prevent the leg [4 from becoming saturated.

The operation of such an arrangement as is shown in Fig. 1 may be understood more clearly by referring to the curves in Figs. 2, 2a, 3, 3a, and 4. In these figures, a represents voltage applied to the exciting or input coil 3; b and 0 represent the positive and negative values of flux at which the leg 4 and its side leg portions 5 and 6 become saturated. Figs. 2 and 2a represent the operation without any appreciable direct currents supplied to the coil [0. Under these conditions, the magnetomotive force applied to the leg 4, represented by d varies about the zero flux axis and lags the voltage a by substantially degrees. Since the flux in the legs 5 and 5 changes only as the magnetomotive force d causes said flux to pass between the two saturating values, voltages are generated in the coils 1 and 8 only during this period. Furthermore, the voltages which are generated in these coils are in phase. Therefore, in Fig. 2a the voltage which is generated in each of the coils l and 8 is represented by h and since these two coils are in series, the total output voltage across these coils may be represented by i which is double h. If the coil I0 is supplied with sufficient direct current to impress upon the leg 5 a bia magnetomotive force represented by j in Fig. 3 and to impress a bias magnetomotive force on leg 0 as represented by g in Fig. 3, the total output voltage i is substantially decreased as represented in Fig. 3a. Under these conditions, the alternating magnetomotive force d5 which is applied by the coil 3 to the leg 5 varies about the bias 1 as an axis and lags the voltage a by substantially 90 degrees as before. The alternatingv magnetomotive force d6 applied to the leg 8 by the coil 3 varies about the bias 9 as an axis and likewise lags the voltage a by substantially 90 degrees. Under these conditions, the flux e! of the leg 5 which passes through the coil 1 is advanced in phase and the flux e8 of the leg 6 which passes through the coil 8 is delayed in phase.

Therefore, as shown in Fig. 3a, th voltages h! and k8 generated in the coils l and 8 respectively are no longer in phase but are delayed and advanced respectively to the same degree as the fluxes which generate them. Therefore the total output voltage i which still is the sum of the voltages of the coils i and 8 is reduced considerably in amplitude, with a somewhat increased width. However, in most applications to which such peaking transformers are put, the amplitude of the peaked output wave is the significant or controlling factor and therefore the widening of the voltage peak is non-objectionable.

It will be seen from the foregoing that by properly selecting the constants of the system, a relatively small value of direct current supplied to the coil Hiwill vary the magnitude of the peaked output voltage wave to a comparatively great degree. For example, the controlling characteristics of such a system may be represented in Fig. 4 in which milliamperes of direct current bias supplied to the coil in may be plotted along the horizontal axis and the peakoutput voltage in kilovolts may be plotted along the vertical axis. The resultant variations may be represented by the curve It in Fig. 4. Of course, it is to be understood that the comparative values as represented in Fig. 4 may be varied over very wide limits by properly selecting the constants of the system as shown in Fig. 1.

Instead of connecting the coils l and 8 so that their voltages add, these coils can be connected so that their voltages oppose each other as represented in Fig. 5. In such an arrangement, when no direct current is supplied to the coil in, the voltages of the coils 1 and 8 are equal and opposite, and the output voltage haszero amplitude. When the coil I0 is supplied with direct current, the separation as represented in Figs. 6, 6a, and 6b ensues. In these figures, the reference numerals'have the same significance as in Figs. 2-4. As previously explained, the voltages h! and 728 are no longer in phase with each other, but are displaced to a degree which by proper design may be that as represented in Fig. 6a. The output voltage from the coils l and 8 under these conditions, consists of a succession of such peaked alternations as is represented in Fig. 6a. If it is desired to have each impulse uni-directional, a rectifying bridge l6 may be connected to the output of the coils 1 and 8 as represented in Fig. 5. Under these conditions, the two voltage peaks of the alternation represented in Fig. 6a are made uni-directional, giving the resulting output impulse as represented in Fig. 61 Under these conditions, the voltage appearing at the output of the rectifying bridge l8 consists of a succession of such double peaked impulses as shown in Fig. 6b.

The peaked output voltage of this invention may be applied to any desired use. One of these uses is in connection with the control of an electrical space discharge tube. Such an application is represented in Fig. 7 in which electronic tube I1 is shown provided with an anode II and a cathode l8, preferably of thermionic type. The tube is provided with a control grid 20 which permits a discharge to start between the cathode and anode, when the grid is supplied with a starting voltage impulse. The tube is adapted to be supplied with alternating current from a pair of terminals 2| and 23. The terminal 2| is connected through a load 22 to the anode IS. The terminal 23 is connected directly to the cathode ID. The peaked output voltage of the coils I and I is connected between the cathode l9 andthe grid 20. It is usually desirable in such instances to control the phase at which the igniting impulse is supplied to the igniting electrode. For this reason, a controllable phase shift device 24 of any suitable type is energized from the terminals 2| and 23 and has its output connected to the energizing coil 3 of the peaking transformer. As previously indicated, the amount of direct current power necessary for controlling the output of such a peaking transformer is relatively slight, and may be supplied in the arrangement shown in Fig. 7 from a thermocouple 25. The device 25, in some instances, may consist of a photo-electric cell or any other desired source of direct current.

The system illustrated in Fig. 7 operates as described in Fig. 1 so as to supply peaked voltages to the grid 20. In absence of energization of the coil in from the thermocouple 25, the amplitude of the peak voltage thus supplied is suflicient to initiate the discharge during each conducting half cycle of the alternate voltage applying to the tube H. The point at which this firing voltage impulse is supplied to the electrode 20 is determined by the setting of the phase shift device 24. If, however, the thermocouple 25 is heated so as to operate the coil III with direct current, the output voltage of the coils I and 8 is reduced to such an extent that it is no longer suflicient in magniture to ignite the tube l1 and thus the tube stops conducting current. It will be seen therefore, that the tube I! which may deliver large amounts of power to the load 22, can be energized and deenergized at will by the relatively small amount 01 energy delivered from the thermocouple 25.

Instead of utilizing direct current for supplying the saturating magnetomotive force, such saturating magnetomotive force can be supplied and controlled in other ways. For example, a movable magnet may be utilized for this purpose as illustrated in Fig. 8. In this figure, where the elements are identical with those shown in Fig. 1, the same reference numerals are applied thereto. In Fig. 8 the central leg of Fig. l is replaced by a pair of pole pieces 26 and 21 between which an armature 28 is rotatably mounted. The armature is made in the form of a permanent magnet although if desired, it could be in the form of an electromagnet. A short circuited turn 29 corresponding to the short circuited turn ll of Fig. l is provided on one of the pole pieces. The armature 28 is mounted upon a rotatable shaft 10 provided "with some suitable means for rotating it such as a crank 3!.

The operation of the arrangement shown in Fig. 8 is identical with that described in connection with Figs. 1-4. However, in connection with Fig. 8, the magnetomotive force which is supplied as a bias to the legs 5 and 6 varies with the angular relationship between the pole pieces 28 and 21 and the armatur 28. Thus the operation of the device shown in Fig. 8 with the armature 28 in line with the pole pieces can be between the pole pieces 26 and 21.

21 can be represented by Figs. 2 and 2a in which,

an increase in the amplitude of the output voltageis secured. Fig. 4 also can represent the operating characteristics of the arrangement shown in Fig. 8 if the angular displacement from vertical position of the magnetic armature 28 is plotted along the horizontal axis.

Instead of utilizing a single movable magnet' as shown in Fig. 8 a plurality of movable mag- I nets can be utilized as illustrated in Figs. 9 and 10. Here likewise, where elements are identical with those in Fig. 8, the same reference numeral are applied; In Figs. 9 and 10, the single movable magnet of Fig. 8 is replaced by a plurality of magnets 32 mounted on a wheel 33 which is rotatably supported on a shaft 34. The shaft may be rotated by any suitable means which preferably consists'of a synchronous motor 35.

If the arrangement shown in Figs. 9 and 10 applied, for example, to a system as shown in Fig. 7, the synchronous motor 35 can be driven from the same source of alternating current as that which energizes the coil 3. Under these conditions, the constants of the system and the number of magnets 32 can be so selected that during each cycle, one of the magnets 32 passes These can be so adjusted that they are in alignment during each conducting half cycle applied to the tube ll.

Under these conditions, the amplitude of the output voltage of the coils 1 and 8 is maintained at a reduced value so that the tube i1 does not fire. In order to cause the tube I1 to fire the magnets 32 are made removable. Therefore, as one of the magnets 32 is removed, the tube II will fire and conduct current during the'cycle corresponding to the removed magnet. By properly selecting magnets 32 for removal, any desired sequence of operationof the tube I! or any other device controlled by the coils I and 8 may be produced.

If, instead of having the voltage of the coils I and 8 add, the arrangement of these coils as represented in Fig. is utilized, the opposite effect is produced, namely the tube i1 fires whenever one of the magnets 32 is in alignment with its associated pole pieces and the tube is prevented from firing merely by removing one or more of the magnets 32.

In some cases, it may not be desirable to have each of the elements 32 in itself a permanent magnet, but rather a magnetic armature member. Under these conditions a D. C. exciting coil 36 can be mounted on on of the pole pieces 21 and the usual short circuited loop 31 may be mounted on the other pole piece 25. The operation under these conditions will be exactly the same a if the members 32 were themselves permanent magnets. A similar variation could be introduced into Fig. 8.

Another mode of operation of the arrangement shown in Fig. 9 could be to have the coil 36 excited with a sufficient magnitude of current to produce an initial saturation of the legs 5 and 6 so as to produce an initial phase displacement between the voltages of coils l and 8. If, under these conditions, the members 32 are in the form of permanent magnets polarized so as to. oppose the magnetization of the coil 36, each of the magnets 32 as it comes into alignment with the poles 26 and 21 will cancel the magnetomotive force of the coil 38 and eliminate the initial phase displacement between said voltages. Here, likewise, as each magnet 32 comes into alignment with the pole pieces 26 and 21, the amplitude of the output voltage across the coils 1 and 8 will be increased and as said magnet passes out of such alignment the amplitud of the output voltage will be decreased.

The relative values of the maximum and minimum amplitudes of output voltage of peaking transformers constructed in accordance with my invention may be increased by utilizing somewhat more complex forms thereof. Anhrrangement of this kind is shown in Fig. 11. Here likewise, where elements are identical with those shown in Fig. 1, the same reference numerals are applied. In Fig. 11 the central direct current bias leg is replaced by a central leg 38 subdivided at its upper end into three smaller legs 39, 40. and M. The legs 33, 40, and 4| may be provided with short circuited rings 42, 43, and 44 respectively. The saturable leg 4 is subdivided into four sections, 45, 46, 41 and 48 instead of the two sections of Fig. 1. In Fig. 11, the saturable leg sections 45-43 are provided with coils 49, 50, 5| and 52 respectively. The D. C. saturating coil Ill is placed upon the main leg 38.

The operation of the device shown in Fig. 11 may be best understood by referring to Figs. l2, l3, and 13a. Here likewise, the same reference letters are applied as in the case of Figs. 2 and 3a, where the purves are identical. In Fig. 12 m represents the voltage of one of the coils 45-52. Therefore the total voltage 1: across all of the coils 45-52 is four times the value m. In Fig. 13

p, r, s, and t represent the bias magnetomotive forces on legs 46, 45, 48, and 4! respectively. Due to the fact that the resultant magnetomotive forces applied to the legs 4548 respectively vary about the bias fluxes pt as axes, the voltages generated in the coils 49-52 are displaced in phase with respect to each other as explained in connection with Fig. l. Thisrelative displacement between these voltages is represented in Fig. 13a. The summation of these displaced voltages' is also represented in Fig. 13a by n. A comparison of the peak amplitude of the voltages of Figs. 12 and 13a shows that in the arrangement of Fig. 11 a greater change in the amplitude of the output voltage is obtainable by this arrangement than by the previously described embodiments.

Of course, it is to be understood that this invention is not limited to the particular details as described above as many equivalents will sugest themselves to those skilled in the art. For example, instead of utilizing direct current for the saturating magnetomotive force, alternating currents of various kinds could be utilized in particular embodiments. Also, different features of each embodiment could be incorporated into each of the other embodiments. Various other applications of the principles enunciated herein could be utilized by persons skilled in the art. It is accordingly desired that the appended claims be given a broad interpretation commensurate with the scope of the invention within the art.

What is claimed is:

1. A peaking transformer system comprising a magnetic core having primary and secondary portions spaced from each other, said secondary portion being divided into a plurality of separate parts and being more readily saturable than said primary portion, a primary winding on said primary portion, means for exciting said primary winding with a periodically varying voltage to set up a periodically varying primary flux, said core having a leakage path portion to bypass a portion of said primary flux away from said secondary portion, a separate 5800131181? winding CD11 on ferent directions in diflerent secondary parts.

with respect to the varying flux set up in said secondary parts by said primary winding, and a short-circuited turn on said bias flux leg to impede the passage of primary flux through said bias said primary volta e being sufllcient to cause saturation of said secondary portion.

2. A peaking transformer system comprising a magnetic core having primary and secondary portions spaced from each other, said secondary portion being divided into a plurality of separate parts and being more readily saturable than said primary portion, a primary winding on said primary portion, means for exciting said primary winding with a periodically varying voltage to set up a periodically varying primary flux, said core having a leakage path portion to bypass a portion of said primary .iiux away from said secondary portion, a separate secondary winding coil on each of said secondary parts, said secondary coils being connected in series, the resultant voltage of said secondary coils being impressed upon a common load device, said core also having a bias flux leg for passing a unidirectional bias flux in different directions in different secondary parts with respect to the varying flux set up in and secondary parts by said primary winding, said bias flux leg being subdivided at one end into a plurality oi sub-legs, each of said sub-legs extending to a point intermediate two of said separate secondary parts, said primary voltage being suflicient to cause saturation of said secondary portion.

3. A peaking transformer system comprising a magnetic core having primary and secondary portions spaced from each other, said secondary portion being divided into a plurality of separate parts and being more readily saturable than said primary portion, a primary winding on said primary portion, means for exciting said primary winding with a periodically varying voltage to set up a periodically varying primar flux, said core having a leakage path portion to bypass a portion of said primary flux away from said secondary portion, a separate secondary winding coil on each 01 said secondary parts, said secondary coils being connected in series, the resultant voltage of said secondary coils being impressed upon a common load device, said core also having a bias flux leg excited by a coil supplied with direct current for passing a unidirectional bias flux through said secondary parts, a short-circuited turn on said bias flux leg to impede the passage of primary flux through said bias leg, said primary voltage being sufllcient to cause saturation of said secondary portion, of said primary winding and said coil on said bias flux leg, one sending flux all in the same direction through said separate secondary parts and the other sendin flux in diiferent directions through said separate secondary parts.

HANS KLEMPERER.

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