US2026771A - Electron discharge device control system - Google Patents

Description

Jam 7, 193 c BRYNHILDSEN ETAL ELECTRON DISCHARGE DEVICE CONTROL SYSTEM Flled Nov 25, 1953 Patented Jan. 7, 1936 UNITED STATEfi A'E'ENT FFIQE ELECTRON DISCHARGE DEVICE CONTROL SYSTEM Application November 25, 1933, Serial No. 699,660 In Germany December 17, 132

19 Claims.

This invention relates in general to the control of electric current converting systems employing electron discharge devices and more particularly to voltage regulating means for a plurality of converting units in series connection.

Electron discharge devices are frequently utilized in electric current converting systems such as rectifying, inverting, f equency changing and direct current voltage converting systems When a system of the above character is to operate directly at very high voltages there is a danger of faulty operation of the electron discharge de vice, and it is therefore frequently preferred to utilize a plurality of converting units connected in series instead of a single unit to reduce the danger of disturbances within the system. To regulate the output voltage of such a system over a considerable range it is then generally necessary to provide each converting unit with separate regulating means, thereby rendering the installation complicated and expensive. By controlling the operation of some of the converting units so as to cause such units to operate alternately in conjunction with and in opposition to the remaining units, the voltage of the system may be regulated by simpler and less expensive means. Some of the units then transmit energy in one direction or the other units may retransmit a portion of such energy in the opposite dition.

It is therefore among the objects of the present invention to provide a current converting system employing a plurality of serially connected electron discharge devices in which energy may be transmitted simultaneously in both directions of flow.

Another object of the present invention is to provide a current converting system employing a plurality of serially connected electron discharge devices in which some of the devices transfer energy in one direction from a source and other devices may return a portion of such energy to the source.

Another object of the present invention is to provide a current converting system employing a plurality of serially connected electron discharge devices in which the output voltages of some of the devices may oppose the output voltages of the other devices.

Another object of the present invention is to provide a current converting system employing a plurality of serially connected electron discharge devices in which the output voltages of some of the devices may be reversed.

Objects and advantages other than those above ignates an alternating current supply line energized at any desired voltage of any frequency and having any nLLnber of phases, herein represented as a three phase line. It is assumed that energy is to be converted between line 6 and a direct current line I, 8. Line 6 is accordingly connected with the primary winding 9 of a transformer having a secondary winding I l comprising a plurality of phase displaced portions connected in star to form a neutral point connected with conductor l. The different phase portions of winding ii are severally connected with the anodes E2 of a vapor type electron discharge device l3 having a cathode l4 and hereinafter designated as rectifier 13 for the sake of brevity.

Cathode M is connected with the neutral point of another secondary winding it in inductive relation either with winding 9 or with a separate winding ii to form therewith a second transformer unit. Winding I! may be energized from any suitable source of alternating current and is preferably connected with line 6, although it will be understood that the sources energizing windings 9 and I! may be entirely independent. Although transformers 9, H and [6, ll have been represented as being similar in their connections, such transformers may be connected in different manner and the voltages of windings i l and 16 need not be in any particular relation except that the range of regulation obtainable is dependent upon such relation. The different portions of winding l are severally connected with the anodes E8 of a second rectifier I9 having a cathode 2! connected with conductor 8. Rectifiers l3 and is are thus operatively connected in series across line '1, 8 with a current smoothing reactor 22 connected in the line if so desired.

Windings 9 and l! are preferably connected with line 6 through a circuit breaker 23 provided with sets of contacts for the connection of line 8 with the auxiliary circuits of rectifiers l3 and 9. The auxiliary contacts of circuit breaker 23 connect line 5 with the coil of a time delay relay Z l operable to connect line 55 with the ignition and excitation transformers 26 and 21 supplying ignition and excitation currents to rectifiers l3 and I9. Rectifier i3 is provided with an ignition anode 28 and with excitation anodes 29 which are connected with transformer 26 in any suitable well known manner to cause striking of an arc within rectifier i3 and continued excitation of such arc upon energization of transformer 26. Rectifier I9 is likewise provided with an ignition anode 3i and excitation anodes 52 connected with transformer 2?.

Rectifier i9 is further provided with a plurality of control electrodes 33 severally controlling the attachment of the arc to the different anodes of rectifier 59. Each control electrode 33 is connected through resistors as at 35 and 36 with the negative terminal of a suitable source of direct current such as a direct current generator 31. The negative terminal of generator 3'? is also connected with cathode 21! through a resistor 38 and contacts 39 of a relay 4| while the positive terminal thereof is connected with cathode 2! through a second resistor d2. Resistors 38 and 42 thus constitute a voltage divider whereby the potentials of the terminals of generator 3? are maintained in invariable relation with the potential of cathode 2!.

The shaft of generator 3'5 drives the brush 43 of a distributor 35 provided with a plurality of conductive segments. Alternate segments of distributor 3d are severally connected with the different control electrodes 33 through resistors 35, each segment also being connected with the adjacent idle segment through a capacitor i! in parallel with a resistor 46. The capacitor is provided for the purpose of preventing arcing at the segments while the resistor permits discharge of the capacitor between successive revolutions of the brush 53. Brush i3 is connected with the positive terminal of generator 3? through contacts 38 of relay 5i the coil of which is energized from a current transformer 49 inserted in the connection between line5 and windings 9 and I7. Operation of relay M in response to the magnitude of the current of current transformer 49 causes the connection of brush it with generator 37 to be opened and causes cathode iii to be directly connected with the positive terminal of generator 3? through contacts 5! of relay 4|. Current transformer 49 is short circuited by means of contacts 52 of circuit breaker 23 when the main contacts of such circuit breaker are 'open to avoid undesired operation of relay ll in response to surges resulting from switching operations of circuit breaker 23.

Brush 45 and generator 57: are rotated at synchronous speed by means of a synchronous motor 53 having an armature 5t energized from line 5 and having a plurality of field windings 55, 5'7 and 58. Such field windings are short circuited during starting operation of the motor through the contacts of a relay 59 which also controls the circuit of the shunt field winding of generator 31. The coil of relay 55 is connected in series with a rheostat 6! in the excitation circuit of rectifier l 9, whereby rheostat H is energized with substantially uniform direct current, a portion of such current fiowing through windings 56, 51 and 58 during synchronous operation of motor 53. Rheostat 5! is adjustable to permit obtaining any desired distribution of current between windings 56, 57: and 58 and therefore any desired angular relation between the field structure of the motor and the rotating magnetic field of the armature. A resistor 62 may be connected in parallel with the coil of relay 59 and rheostat 6| to limit the voltage surges resulting therein from the operation of relay 59.

The operation of the system will now be considered assuming first that line 6 is energized and that line I, 8 is to be energized at a voltage 5 gradually increasing from zero to the maximum value thereof. Closure of circuit breaker 23 causes transformers 9, II and Hi, I? to be energized. Armature 54 of motor 53 is then energized through the auxiliary contacts of circuit breaker 10 23. Windings 56, 57 and 58 being short circuited through the contacts of relay 59, motor 53 operates as an induction motor and reaches a speed closely approaching the synchronous speed thereof. After a predetermined time delay, relay 24 closes the contacts thereof to cause energization of transformers 26 and 21, whereby an arc is struck and is maintained in each of rectifiers l3 and #9 by the ignition and are maintaining circuits operating in a well known manner. When the fiow of current through transformer 21 reaches the full value thereof, such current causes operation of relay 59 which removes the short circuit of windings 56, 57 and 58 and completes the circuit of the field winding of generator 3? 25 thereby permitting self excitation of such generator. Motor 53 at that time is operating in synchronism with the voltage of line 6, the relative position of the field windings with respect to the rotating magnetic field of the motor being determined by the adjustment of rheostat 6i The potentials of the terminals of generator 31 being fixed with respect to the potential of cathode 2| by means of resistors 38 and 42, control electrodes 33 receive, from the negative 35 terminal of generator 37, a potential which is negative with respect to the potential of cathode 2i. Brush #3 then sequentially impresses, on the several control electrodes, a potential from generator 37 which is positive with respect to the 40 potential of cathode 2| to release the sequential fiow of current through the anodes associated with the control electrodes.

At the time of closure of circuit breaker 23, rheostat 6! is adjusted in such manner that each control electrode 33 is positively energized in the portion of the voltage cycle during which the associated anode receives a negative voltage from winding 56 to thereby introduce, in line I, 8, a negative voltage opposing the positive voltage introduced therein by rectifier 53 operating in the well known uncontrolled manner. If the negative voltage introduced by winding l6 and rectifier l 9 is at least equal to the positive voltage introduced by winding H and rectifier I3, the 55 resulting voltage impressed on line 1, 8 is equal to zero or is even negative and line i, 8 receives no current.

Movement of rheostat 65 in the one direction causes the field structure of motor 53 and brush 3 to be given an increasing lead with respect to the rotating magnetic field inducted by winding 54 to thereby advance the moment at which each control electrode is energized during the voltage cycle of line 6. The negative terminal voltage of winding l6 and rectifier !9 then becomes lower, as is well known, and when such voltage is lower than the voltage of winding II and rectifier I 3 a current flow is established from conductor 1 through rectifiers l3 and ii! to conductor 8. Such current fiow occurs at a voltage which is the difference of the average voltages of rectifier I3 and rectifier I9. During such operation rectifier I 3 converts energy from line 6 to line 7, 8 while rectifier He acts as a direct current inverter to return a portion of such energy from line I, 8 to line 6. The balance of the energy is then utilized in current consuming devices (not shown) connected with line 1, 8. Continued movement of rheostat 6| causes continued advance of the times of energization of the control electrodes and a gradual decrease of the voltage of rectifier l9 to zero. Line I, 8 then receives energy only from rectifier E3, the flow of current through rectifier l9 then occurring without transfer of energy between the two lines. The times of energization of control. electrodes 33 may then be further advanced whereby the output voltage of rectifier l9 gradually increases positively from zero, each control electrode then being positively energized when the associated anode receives a positive voltage from winding l6. Rectifier 19 then no longer operates as an inverter but cooperates with rectifier [3 in rectifying alternating current received from line 6. The times of energization of control electrodes 33 may be advanced to such extent that each control electrode becomes positive when the associated anode becomes positive with respect to the anode carrying current at the time considered. Rectifier I9 then delivers current at the maximum output voltage thereof and further advance of the times of energization of control electrodes 33 is without efi'ect on the operation of the rectifier. The voltage of line i, 3 is then at a maximum value equal to the sum of the voltages of rectifiers l3 and I9.

By reversing the motion of rheostat iii the voltage of line I, 8 may be again reduced to zero by first gradually reducing the voltage of rectifier l to zero and thereafter reversing and increasing the voltage of such rectifier. Further reverse movement of rheostat 52 will cause control electrodes 33 to become positive to release the flow of flow of current through the as sociated anodes to thereby impress on line 7, 8 a negative voltage greater than the positive volage of rectifier I3. If line i, 8 is connected with loads or with sources operable to impress thereon a reverse voltage, rectifier l9 may then receive energy from line i, 8 and convert such energy into alternating current supplied to line 6, a portion of such energy being returned at a lower voltage to line i, 8 by means of rectifier 13.

When rectifier i9 is operated at a voltage opposing that of rectifier 13, a certain amount of energy is therefore circulated between the two rectifiers, thereby causing losses in the circuit thereof. Such losses are, however of reduced importance when compared to the advantage of simplification of the control system, especially when a large range of regulation is required only during short periods of time.

Upon occurrence of a disturbance such as a short circuit in line 1, 8, current transformer is energizes the coil of relay ii with an increased amount of current and causes such relay to operate to disconnect brush 43 from generator Bl. Control electrodes 33 are then constantly maintained at a potential which is negative with respect to the potential of cathode 26 by the full amount of the voltage of generator 3'! as a result of the opening of contacts 39 and closure of contacts 5!. The flow or current is thereby caused to be extinguished in rectifier iii and therefore also in rectifier i3 and in line i, 8.

From the above description of the operation of the system it will be apparent that serially connected rectifiers l3 and is are operable to cause simultaneous transfer of energy in both directions between lines 6 and l, 8. Line I, 8 then receives energy from line 6 through rectifier l3,

and rectifier I9 is operable to cause the fiow of energy therethrough from line i, back to line 6. The control means for rectifier 19 are operable to cause the voltage impressed by rectifier E9 on line i, 8 to oppose the voltage impressed on, such line by rectifier Hi. The voltage of rectifier It may be regulated and reversed by means of rheostat 6| motor 53, distributor 44 and control electrodes Upon occurrence of abnormal conditions within the system the control electrodes of rectifier iii are negatively energized to cause interruption of the flow of current through both rectifiers.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. In an electric current converting system, an electric current line, a plurality of electron discharge devices serially connected across said line, a second electric current line connected with said devices, and means controlling one of said devices to cause simultaneous transfer of energy through said devices in both directions between said lines.

2. In an electric current converting system, an electric current line, a plurality of electron discharge devices serially connected across said line, a second electric current line connected with said devices and operable to supply current through one oi said. devices to the first said line, and means operable to control another of said devices for causing flow of energy therethrough from the first said line to the second said line.

3. In an electric current converting system, an electric current line, a plurality of electron discharge devices serially connected across said line,

a second electric current line connected with said devices for transferring energy therethrough to the first said line, and means operable to control one of said devices for causing flow of energy therethrough from the first said line to the second said line.

4-. In an electric current converting system, an electric current line, an electron discharge device, a second electron discharge device, means for connecting said discharge devices with said line, a second electric current line, means for o eratively connecting said devices serially across the second said line to cause transfer of energy from the first said line to the second said line, and means controlling the second said discharge device operable to cause transfer of energy therethrough from the second said line to the first said line.

5. In an electric current converting system, an electric current line, an electron discharge device, a second electron discharge device, means for conncctin said discharge devices with said line, a second electric current line, means for operatively connecting said devices serially across the second said line to cause impression of voltage thereon, and means controlling the second said discharge device and operable to cause the voltage impressed on the second said line by the second said discharge device to oppose the vo1tage impressed thereon by the first said discharge device.

6. In an electric current converting system, an electric current line, an electron discharge de vice, a second electron discharge device, means for connecting said discharge devices with said line, a second electric current line, means for operatively connecting said devices serially across the second said line to cause impression of voltage thereon, means controlling the second said discharge device and operable to cause the voltage impressed on the second said line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device, and means controlling the last said means to regulate the voltage impressed on the second said line by the second said discharge device.

7. In an electric current converting system, an electric current line, an electron discharge device, a second electron discharge device, means for connecting said discharge devices with said line, a second electric current line, means for operatively connecting said devices serially across the second said line to cause impression of voltage thereon, means controlling the second said discharge device and operable to cause the voltage impressed on the second said line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device, and means controlling the last said means to cause reversal of the voltage impressed on the second said line by the second said discharge device.

8. In an electric current converting system,

an electric current line, an electron discharge device, a second electron discharge device, means for connecting said discharge devices with said line, a second electric current line, means for operatively connecting said devices serially across the second said line to cause impression of voltage thereon, means controlling the second said discharge device and operable to cause the voltage impressed on the second said line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device. and means controlling the last said means and operative to regulate and reverse the voltage impressed on the second said line by the second said discharge device.

9. In an electric current converting system, an electric current line, an electron discharge device, a second electron discharge device, means for connecting said discharge devices with said line, a second electric current line, means for cperatively connecting said devices serially across the second said line to cause transfer of energy from the first said line to the second said line, means controlling the second said discharge device and operable to cause transfer of energy therethrough from the second said line to the first said line, and means responsive to abnormal. conditions in the system and controlling the operation of the second said discharge device to cause interruption of the flow of current between said lines.

10. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated with a control electrode and a cathode, means for connecting said discharge devices With said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct ourrent line, and means controlling said control electrode and operable to cause transfer of energy from said direct current line back to said alternating current line through the second said discharge device.

11. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated With acontrol electrode and a cathode, means for connecting said discharge devices With said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct current line, means controlling said control electrode and operable to cause transfer of energy from said direct current line back to said alternating current line through the second said discharge device, and means controlling the last said means to regulate the flow of energy through the second said discharge device.

12. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated with a control electrode and a cathode, means for connecting said discharge devices with said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct current line, means controlling said control electrode and operable to cause transfer of energy from said direct current line back to said alternating current line through the second said discharge device, and means controlling the last said means to cause reversal of the flow of energy through the second said discharge device.

13. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated with a control electrode and a cathode, means for connecting said discharge devices With said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct current line, means controlling said control electrode and operable to cause transfer of energy from said direct current line back to said alternating current line through the second said discharge device, and means controlling the last said means to regulate and reverse the fiow of energy through the second said discharge device.

14. In" an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated with a control electrode and a cathode, means for connecting said discharge devices with said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct current line, and means controlling said control electrode and operable to cause the voltage impressed on said direct current line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device.

15. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated with a control electrode and a cathode, means for connecting said discharge devices With said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct current line, means controlling said control electrode and operable to cause the voltage impressed on said direct current line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device, and means controlling the last said means to regulate the voltage impressed on said direct current line by the second said discharge device.

16. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated with a control electrode and a cathode, means for connecting said discharge devices with said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct current line, means controlling said control electrode and operable to cause the voltage impressed on said direct current line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device, and means controlling the last said means to cause reversal of the voltage impressed on said direct current line by the second said discharge device.

1'7. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated With a control electrode and a cathode, means for connecting said discharge devices with said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line tosaid direct current line, means controlling said control electrode and operable to cause the voltage impressed on said direct current line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device, and means controlling the last said means to regulate and reverse the voltage impressed on said direct current line by the second said discharge device.

13. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated with a control electrode and a cathode, means for connecting said discharge devices with said line, a direct current line, means for operatively connecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct current line, means controlling said control electrode and operable to cause the voltage impressed on said direct current line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device, and means responsive to abnormal conditions in the system controlling said control electrode to cause interruption of the flow of current between said lines. 19. In an electric current rectifying system, an alternating current line, an electron discharge device, a second electron discharge device having an anode associated with a control electrode and a cathode, means for connecting said discharge devices with said line, a direct current line, means for operativelyconnecting said discharge devices serially across said direct current line and operative to cause supply of current from said alternating current line to said direct current line, means controllin said control electrode and operable to cause the voltage impressed on said direct current line by the second said discharge device to oppose the voltage impressed thereon by the first said discharge device, and means responsive to flow of excessive current between said lines to cause said control electrode to become constantly negatively energized with respect to said cathode to cause interruption of the flow of current through both said discharge devices.

CHRISTEN BRYNHILDSEN. ERWIN KERN.

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