USRE20391E

USRE20391E - Electric valve converting system

Info

Publication number: USRE20391E
Authority: US
Publication date: 1937-06-01

Description

June 1, 1937- c. A. sABBAH ELECTRIC VALVE CONVERTING SYSTEM Original Filed May 5, 1953 Fig. 2.

Inventor: i Camil A. Sabbah,

His Attorney.

i Reissued June l, 1937 y *Re 'I UNITED STATES PATENT OFFICE ELECTRIC VALVE CONVERTING SYSTEM lOriginal No. 1,961,080, dated May 29, 1934, Serial No. 669,553, May. 5, 1933. Application for reissue May 23, 1936, Serial No. 81,547

17 Claims.

This invention relates to electric valve converting systems and more particularly to such systems suitable -for transmitting energy between direct 60 with one terminal of the high voltage circuit. It

is to be understood'that the terms "low voltage and high voltage do not imply any absolute values but only the relative values of the voltages In case the electric` valves I1-22, inc., are of current circuits of diiIerent voltages. of the two direct current circuits. The system Heretofore, there have been proposed numerthus in eiect becomes a direct current autotranss ous electric valve converting systems for transformer in which the full windings of the reactor mitting energy between direct and alternating device comprise the high voltage windings and current circuits, independent alternating current the portions included between the alternating f circuits of the same or different frequencies, or current terminals and the common terminal of lo direct current circuits of diiTerent voltages. Apthe low voltage direct current circuit comprise lo paratus of this latter type have, in general, comthe secondary windings, or vice versa. prised separate inverting apparatus and rectify- For a better understanding of the invention, ing apparatus coupled through a common .altertogether with other and further objects thereof,

nating cunent circuit. In such an apparatus, the reference is had to the following description takenergy passing from one direct current circuit to en in connection with the accompanying drawing l5 the other, ilows through two independent groups and its scope will be pointed out in the appended o! valves so that the kv-a. rating of the equipclaims. In the drawing Fig. 1 illustrates a conment as a whole is substantially greater than the verting system embodying the invention for transkv-a. transmitted between the two direct current mitting energy between two direct current cir- 2 circuits,- cuits of different voltages, while Fig. 2 shows a 20 It is an object of the invention to provide a new modied form of the invention which is suitable and improved electric valve converting system for supplying in addition an alternating current for transmitting energy between two direct curload circuit. rent circuits of different voltages which will over-A Referring .now more particularly to Fig. 1 of u come the above-mentioned disadvantages of the the drawing, there is illustrated an arrangement arrangements of the prior art, and which will be embodying my invention for transferring energy simple and reliable in operation. between a relatively high voltage `direct current I.It is another object of the invention to provide circuit Ill-I I and a relatively low voltage direct an improved electric valve converting system for current circuit I I-I2, having a common terminal transmitting energy between direct current cir- II. This system includes an electric valve concuits of dierent voltages in which the kv-a. ratverting apparatus comprising a reactance deing of the equipment asa whole will not substanvice I3 having a three-legged magnetic core tially exceed the kv-a. of the energy transmitted member, the several branches of which carry inbetween the circuits. ductive windings Il, I5 and I6. 'Corresponding n -`In accordance with one form of the invention terminals of the windings I4, I5 and I6 are con- 35 illustrated in Fig'.l 2,'an electric valve converting nected to the direct current terminal Ill through apparatus of the type disclosed in United States a group of electric valves I1, I8 and I9, while the Letters Patent No. 1,907,589 granted May 9, 1933 other terminals of these windings are connected isused. That patent discloses a valve converting to the direct current terminal I I through a group 40 apparatus for transmitting energy between diof valves 20, 2| and 22, respectively. Each of the 40 rect and alternating current circuits and comseveral electric valves I1-22, inc., is provided with 'prising a multi-legged reactor, the several an anode, a cathode and a control grid, .and may branches of which carry inductive windings, corbe of any of the several types well known in the responding lterminals being connected to one side art, although it is preferred to use valves of the 5 of= the direct current circuit through one group gaseous or vapor electric discharge type. Each 45 of;y valves and to the other side of the direct curof the windings I4, I5 and .I6 is provided with rent circuit through a second group of valves. an intermediate terminal, these terminals divid- The alternating current circuit is connected to ing the several windings into portionshaving the th'e electrical midpoints of the several inductive same turn ratio. The intermediate terminals windings. In the present invention, illustrated of the windings Il, I5 and I6 are connected to 50 in Figs. l and 2, intermediate terminals of the the several phase terminals of a three phase Y- several inductive windings of the reactor 'are connected inductive network 23, the electrical connected directly together or to the phase terneutral of whichis connected' to the direct current minals of. a polyphase alternating current netterminal I2 through a smoothing reactor 24.

5;, work. The common connection of the inter- However in certain cases the inductive network 23 55 mediate terminals or the neutral point of the may be omitted and the intermediate terminals inductive networkv forms one terminal of the of the windings I I, I5 and I6 connected together low voltage direct. current circuit while the other to form one terminal I2 ofthe direct current terminal of the low voltage circuit is common circuit.

current cannot be, commutated between them, under certain operating conditions, by the grid circuits alone, and it is. necessary to connect the capacitors 25, 25 and 21 in circuit with the windings I4, I5 and I5, respectively, either across the full windings, as illustrated, or across portions thereof. In order to render the several electric valves I1-22, inc., conductive in the proper sequence, their grids are connected to their re'spective cathodes through current limiting resistors. I

2B and appropriate phase windings of the secondary .network 230i a grid transformer, the primary Inetwork 30 of which is connected toan alternating current-circuit 3| of any suitable frequency.

The general principles of operation of the above described converting apparatus per se will be well understood by .those skilled in the art. However, in accordance with the invention as illustrated in Fig. 1 it will be apparent that the phase relation between the grid excitation of the valvesA I1, I3, I9 and valves 20, 2|, 22, energized through the phase windings 29 and 30 is such that the valves in the lower group become conductive in advance of the 4corresponding valves of the upper group.` While the arrangement shown in `Fig. 1 provides a phase angie of 120 between the time that the lower valves become conductive and the time that the corresponding upper valves become conductive other angles just greater than 0`and slightly less thanV 180 may be employed.

In brief, neglecting the leakage reactancepf the device I3, the several windings Il, I5 and I5 serve tomaintain the total magnetomotive force and that of each of the arms of the magnetic core structure I3 at a constant value. In order to satisfy this condition, and the condition that all currentsflowing from one side of the direct current circuit must equal those ilowing-to the other side (neglecting the auxiliary direct current circuit II-I2) it has been demonstrated both analytically and experimentally that each of the several electric valves is conductive for 120 electrical degrees of each cycle, thefvalves becoming conductive in a predetermined sequence at a frequency equal to that of the alternating current circuit 3|, from which the grids of the several electric valves are controlled. In case the inductive network 23 is not connected to an independent source of electromotiye force, the leakage reactance of the reactance device I3 and the inductive network '23 will tend to cause the current in the System to be slightly lagging with respect to the alternating electromotive force of the network 23.

In operation the electromotive forces of the windings are in 'the proper direction to assist commutation and eiIect a transfer of. load current between the valves. This may be accomplished, as is well understood by those skilled in the art, by connecting the capacitors 25, 25 and 21 across the windings Il, I5 and I6, respectively.

'I'he function performed in the operation oi',- the system by the three-legged core structure I3, the windings Il, I5, I5 and the associated capacitors 25, 25 and 21 perhaps will' be clarinedby the following example of one cycle of operation of the valves associated with one leg of the core structure. In the arrangement shown, the grid excitation supplied to the valves I1 and 20 is such that the valve 2liis conductive'for but meanwhile the valve I1 is nonconductive. In order to supply energy to the valve 20, the capacitor 25, having been charged to a certain the gaseous or vapor electric discharge type, the

potential by previous operation, now discharges into the winding I4 so as to supply current to the Y anode of the valve 20. At the end of the conductivity ofthe va1ve'2II, the valve I1- becomes conductive and the .valve 2li now is nonconductive. Thus the current transmitted -by the valve I1 serves. to store energy in the capacitor 25 during the period of conductivity of this valve. At the end of the period of conductivity of the valve I1, the current is' transferred from this valve to the valve I8 and during the conductivity of the valve I8. the valves I1 and 2li both remain nonconductive. During the period when neither of the valves I1 and 20 is conductive, 'the capacitor 25 discharges into the transformer winding in order to maintain the required magnetomotive. force on this transformerl winding, and in doing so it reverses its polarity so that it has the proper capacitors 25, 25 and 21 not only provide commutating potentials to cause the transfer. of current between the valves I1, IB and I5, but also operate as energy storage devices to supply current to the anodes of the valves 2li, 2| and 22.

An alternating electromotive `force may be drawn from the intermediate terminals of the windings I4, I5 and I5. In'addition, however, it has been shown both experimentally and analytically that a unidirectional component of. voltage exists between the electrical neutral of the network 23 and the terminals III and I Iv and that the magnitude of this unidirectional voltage bears a relation to the voltage of the direct current circuit Ill-II dependent on the number of turns of the lower portions of' the windings I 4, I5 and I5 to that of the whole windings. An alternating electromotive force also exists In the windings of the inductive network23 and` this electromotive force may be utilized in an independent alternating current circuit, if desired. This alternating component may be suppressed from the low voltage direct current.l

circuit II-I2 by means of the series reactor 2l or any other suitable iilter circuit. In case the network 23 is omitted, the operation of the remainder of the system is substantially the same. the `alternating components of voltage appearing across the inductive windings I4, I5, and Il andthe reactor 2l. Thus, in eil'ect, theabovedescribed lapparatus comprises a direct current autotransformer, by means of which energy may be transmitted between a relatively high voltage direct current circuit and a relatively low voltage direct current circuit, either of which may be the supply circuit. The power transfer between the circuits may be varied by varying the phase relation of potentials applied to the -grids of the phase converting apparatus by means'of which 4 certain economy in the capacitors may be secured. In this ilgure, two converting apparatus A and'Beach similar to the converting apparatus of Fig. 1 and each having its corresponding elements similarly numbered with the subscripis a and b to identify the converting apparatus of which it is a part, are combined to form a double three' phase converting system With such an arrangement, the electrical neutrals oi.' the networks 23a and 23h are interconnected through an interphase transformer 32, the electrical midpoint of which is connected to the direct current terminal -I2 through the current smoothing reactor 2l. In this arrangement, a single commutating capacitor 33 may be connected across the interphase transformer 32 to provide the necessary commutating electromotive force. In this arrangement, the capacitor` 33 operates at a third harmonic frequency which enables a considerable reduction in its size and cost. In the system of Fig. 2 also, the networks 23a and 23h are illustrated as comprising primary networks of an output transformer, the secondary*V network 3l of which is connected to an alternating current load circuit 35. In this manner, energy may be supplied from a high voltage direct current circuit to a low voltage di-rect current, or lvice versa, and at the .same time energy may be supplied to anlalternating current circuit from .the same apparatus.

' While the preferred embodiments of the invention, asat present, considered, have been described, it will-be obvious to those skilled in the art that various changes and modications may be-made without departing from the invention. and we therefore aim in the appended claims to cover all such changes and modiilcations as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. An electric valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct current circuit, said circuits having a common terminal, an electric valve converting apparatus connected across said high voltage circuit andincluding a plurality of inductive windings provided with' intermediate terminals, said intermediate terminals being interconnected to form the other terminal of said low voltage circuit.

2. An electric valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct current circuit, said circuits having a common terminal, an

`electric valve converting apparatus connected across said high voltage circuit and including a plurality of inductive windings provided with intermediate terminals, and an inductive network interconnecting said intermediate terminals and provided with an electrical neutral forming the other terminal of said low voltage circuit; v 3. An electric valve converting system' comprising a relatively ,high voltage direct current circuit, a relatively low voltage direct current circuit, said circuits havinga common terminal, a plurality of pairs of electric valves, a reactance deviceirovided with a plurality of windings, said valves and windings being connected to form a plurality of paths across said high voltage circuit, each including one of said windings and one of said pairs of valves, a connection between intermediate terminals ofv said windings, forming the other terminal of said low voltage circuit, and means for rendering said valves conductive in a predetermined sequence.

4. An electric'valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct current eircuit, saidV circuits having a common terminal, a polyphase reactance device comprising an n-legged core structure having a winding on each leg, a pair of groups of electricvalves, each connecting corresponding terminals of said windings to one side of said high voltage circuit, each of said windings being provided with an intermediate terminal, a plurality of other windings connected to form an n-phase winding system in terconnecting said intermediate terminals and provided withan electrical neutral forming the other terminal of said low voltage circuit, and means for rendering said valves conductive in a predetermined sequence.

5. An electric valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct current circuit, said circuits having a common terminal, a polyphase reactance device comprising an n-legged core structure having a winding on each leg, a pair of groups of electric valves, each connecting corresponding terminals of said windings to one side f said high voltage circuit, each of said windings being provided with an intermediate terminal, a commutating capacitor connected in circuit with each of said windings, a connection between said intermediatey terminals forming the other terminal, of said low voltage circuit, and means for rendering said valves conductive in a predetermined sequence.

`(i. An electric valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct current circuit, said circuits having a common terminal, a polyphase reactance device comprising an vrl-legged core structure having a winding on each leg, a pair of groups of electric valves, each connecting corresponding terminals of said windings to one side of said high voltage circuit, each ofsaid windings being provided with an intermediate terminal, a commutating capacitor connected in circuit with each of saidV windings, an n-phase inductive network interconnecting said intermediate terminals and provided with an electrical neutral forming the other terminal of said low voltage circuit, and means for rendering said valves conductive in a predetermined sequence.

'1. An electric valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct current circuit, said` circuits having a common terminal, an electric valve inverting apparatus connected across said high voltage circuit and including a plurality of inductive windings provided with intermediate terminals, a plurality of other inductive windings connected to form a winding system interconnecting said intermediate terminals, said winding system having an electrical neutral forming the` other terminal of said low voltage circuit, and an alternating current load circuit including said winding system.

8. An electric valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct current circuit, said circuits having a common terminal,

apolyphase reactance .-device comprising -au n-legged core structure having a winding on each leg, a pair of groups of electric valves, each connecting corresponding terminals of said windings to one side of said high voltage circuit, each of saidwindings being provided with an intermediate terminal, a plurality of other windings connected to form an n-phase winding system interconnecting said intermediate terminals and provided with an electrical neutral forming the other terminal oi' said low voltage circuit.' an alsaid winding system, and means for rendering said valves conductive in a predetermined sequence.

9. An electric valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct' current circuit, said circuits having a common terminal,

- a pair of polyphase reactance devices each comprising an n-legged core structure having a winding on each leg, a pair of groups of electric valves, each connecting corresponding terminals of said windings to one side of said high voltage circuit, each of said windings being provided with an intermediate terminal, and IL-phase inductive network interconnecting the intermediate terminals of the windings of each of said reactance devices and provided with an electrical neutral, an interphase inductive winding interconnecting said neutrals and itself provided with an electrical neutral forming the other terminal of said low voltage circuit, and means for rendering said valves conductive in a predetermined sequence.

10. An electric valve converting system comprising a relatively high voltage direct current circuit, a relatively low voltage direct current circuit, said circuits having a common terminal, a pair of polyphase reactance devices each comprising an n-legged core structure having a wind. ing on each leg, a pair of groups of electric valves, each connecting corresponding terminals of said windings to one side of said high voltage circuit, each of said windings being provided with an intermediate terminal, an n-phase inductive network interconnecting the intermediate terminals of the windings of each of said reactance devices and provided with an electrical neutral, an interphase inductive winding interconnecting said neutrals and itself provided with an electrical neutral forming the other terminal of said low voltage circuit, a commtating capacitor connected across said interphase inductive winding, and means for rendering said valves conductive in a predetermined sequence.

11. An electric valve converting system comprising a direct current input circuit,`a direct current output circuit, a' polyphase reactance device comprising an n`1egged core structure having at least on'e winding on each leg, a group of valves interconnecting said reactance device with said input circuit, a second group 'of valves interconnecting said reactance device with said" output circuit, and means for controlling the conductivity of said valves. Y

12. An electric valve converting system comprising a direct current input circuit, a direct current output circuit, a polyphase reactance device comprising an n-legged core structure having at least one winding on'each leg, a capacitor for each leg connected across at least a portion of `said winding, a group of electric discharge valves interconnecting said reactance device with said' input circuit, a second group of valves interconnecting said reactance device with said output circuit, and means i'or controlling the conductivity ofsaidvalves. n

13. An electric valve converting system comprising direct current `input and output circuits, one of said circuits having a constant potential characteristic and the other having a constant 20,891 Vternating current Aload circuit energized from current characteristic, an energy storage and transfer device including a plurality of capacitors connected in parallel to a plurality 0i' inductive windings, a plurality of electric valves interconnecting said circuits with said device, and means for controlling the conductivities of said valves.

14. An electric valve converting system comprising a constant potential direct current circuit, a constant current direct current circuit, a polyphase reactance device comprising an nq legged core structure having a winding on each leg, a group of electric discharge valves interconnecting said reactance device with said constant potential circuit, a capacitor for each leg of said reactance device and connectedv across that portion of the winding associated with said constant potential circuit, a second group of electric discharge valves interconnectingsaid reactance device with said constant current circuit, and means for controlling the conductivity of said valves.

15. An electric valve converting system for l transmitting energy between two circuits, one of said circuits being a direct current circuit, a polyphase reactance device comprising an n-legged core structure having at least one winding on each leg,. a capacitor for each leg being connectedacross at least a portion of said winding, a group ot electric discharge valves interconnecting said reactance device with one of said circuits, a second group of electric discharge valves interconnecting said reactance device with the other of said circuits, and means for controlling the ,said circuits, an energy storage and transfer device interconnecting said groups of valves, said device comprising an n-legged core structure having a winding on each leg and a capacitor forv each winding, said capacitors each being con- I nected in parallelwith a portion oi' the respective windings, and means for controlling the conductivities oi said valves.

17.- An electric valve converting system for transmitting energy between a constant potential circuit'and a constant current circuit comprising an energy storage andtransfer device having an n-legged core structure provided with a capacitor and at least one inductive winding for each leg.

said capacitors each being connected in parallel with a portion of its associated inductive winding, a group of controlled electric i discharge valves connected between said energy transfer device and one of said circuits for controlling the flow of energy to be storedin said device, a second group ofcontrolled electric discharge valves connected between said energy transfer device and said other circuit for controlling the iiow of energy from said device, and means for controlling the conductivities of said valves.

GENERAL ELECTRIC COMPANY. Assignee of Cami! A. Sabbah, Deceased. By CHARLES E. TULLAR.

Vice President.