Parallel thyristors switching matrices

Claim 2

In a high-voltage solid-state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in at least first and second parallel paths for conducting current between opposite main electrodes of the matrix, each of said paths including at least two of said thyristors in series; b. means for connecting a juncture of adjoining thyristors in said path to a juncture of adjoining thyristors in said second path; c. a resistor-inductor subcircuit; d. means for simultaneously triggering selected ones of said thyristors into conduction while forward voltage is impressed on the matrix; e. means including said selected thyristors and said resistorinductor subcircuit for forming between said electrodes a circuit which conducts the initial current that will flow through the matrix when said selected thyristors are turned on and which limits the magnitude of said initial current, said subcircuit being effective in said circuit to initially absorb and subsequently dissipate energy and to maintain sufficient voltage across the remaining thyristors of the matrix to ensure that they will commence conducting when subsequently triggered; and f. means for triggering all of said remaining thyristors shortly after said selected thyristors are triggered, whereupon each of said first and second paths can conduct its proper share of the total current flowing through the matrix.

Claim 3

In a high voltage solid state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in at least first and second parallel paths for conducting current between opposite main electrodes of the matrix, each of said paths including at least one of said thyristors; b. a saturable core inductor serially connected in said first path; c. said inductor being shunted by a resistor in series with a diode which is poled in opposition to the thyristor in said first path; d. first means adapted for triggering the thyristor in said first path into conduction; e. whereby, when the thyristor in said firSt path is turned on, the magnitude of current flowing in said first path is limited, transient current oscillations are suppressed, and sufficient voltage is maintained across the thyristor in said second path to ensure its conduction when subsequently triggered; and f. second means adapted for triggering the thyristor in said second path after the thyristor in said first path is triggered, whereupon each of said first and second paths can conduct a portion of the total current flowing through the matrix.

Claim 4

In a high voltage solid state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in at least first and second parallel paths for conducting current between opposite main electrodes of the matrix, each of said paths including at least one of said thyristors; b. a saturable core inductor serially connected in said first path; c. said inductor being shunted by a resistor in series with a diode which is poled in opposition to the thyristor in said first path; d. first means adapted for triggering the thyristor in said first path into conduction; e. whereby, when the thyristor in said firSt path is turned on, the magnitude of current flowing in said first path is limited, transient current oscillations are suppressed, and sufficient voltage is maintained across the thyristor in said second path to ensure its conduction when subsequently triggered; and f. second means adapted for triggering the thyristor in said second path after the thyristor in said first path is triggered, whereupon each of said first and second paths can conduct a portion of the total current flowing through the matrix.

Claim 5

The switching matrix as specified in claim 2 wherein a current balancing element is connected in said second path.

Claim 6

The switching matrix as specified in claim 3 wherein first and second paths are paralleled by a third current conducting path comprising at least one thyristor and another current balancing element and wherein said second means is adapted for triggering the thyristor in said third path substantially simultaneously with the thyristor in said second path.

Claim 7

The switching matrix as specified in claim 4 wherein each of said current balancing elements comprises an inductor which is shunted by a resistance element, and wherein the inductors in the respective paths are selected so that when all three paths are conducting and the inductor in the first path is saturated, each of said paths will conduct a predetermined share of the total current flowing through the matrix.

Claim 8

In a high-voltage solid-state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in at least first, second and third parallel paths for conducting current between opposite main electrodes of the matrix, each of said paths including at least two of said thyristors in series; b. a saturable core inductor connected in series with the two thyristors in said first path; c. said inductor being shunted by a resistor in series with a diode which is poled in opposition to the thyristors in said first path; d. at least two current balancing elements serially connected in said second and third paths, respectively; e. first means adapted for substantially simultaneously triggering the thyristors in said first path into conduction; f. whereby, when the thyristors in said first path are turned on, the magnitude of current flowing in said first path is limited, transient current oscillations are suppressed, and sufficient voltage is maintained across the thyristors in said second path and said third path to ensure that they will conduct when subsequently triggered; and g. second means adapted for substantially simultaneously triggering the thyristors in said second and third paths into conduction after the thyristors in said first path are triggered, whereupon each of said first, second and third paths conducts current between said main electrodes.

Claim 9

In a high-voltage solid-state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in at least first, second and third parallel paths for conducting current between opposite main electrodes of the matrix, each of said paths including at least two of said thyristors in series; b. a saturable core inductor connected in series with the two thyristors in said first path; c. said inductor being shunted by a resistor in series with a diode which is poled in opposition to the thyristors in said first path; d. at least two current balancing elements serially connected in said second and third paths, respectively; e. first means adapted for substantially simultaneously triggering the thyristors in said first path into conduction; f. whereby, when the thyristors in said first path are turned on, the magnitude of current flowing in said first path is limited, transient current oscillations are suppressed, and sufficient voltage is maintained across the thyristors in said second path and said third path to ensure that they will conduct when subsequently triggered; and g. second means adapted for substantially simultaneously triggering the thyristors in said second and third paths into conduction after the thyristors in said first path are triggered, whereupon each of said first, second and third paths conducts current between said main electrodes.

Claim 10

The switching matrix as specified in claim 6 wherein each of said current balancing elements comprises an inductor, and wherein resistance elements are provided in shunt with each of said current balancing inductors.

Claim 11

The switching matrix as specified in claim 7 wherein said saturable core inductor is disposed between the two thyristors in said first path, and wherein a resistance means is connected between the first-mentioned resistor and a juncture of adjoining thyristors in said second path, and wherein another resistance means is connected between said first-mentioned resistor and a juncture of adjoining thyristors in said third path.

Claim 12

The switching matrix as specified in claim 8 wherein the inductors in the respective paths are selected so that when all three paths are conducting and the inductor in the first path is saturated, each of said paths will conduct a predetermined share of the total current flowing through the matrix.

Claim 13

In a high-voltage solid-state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in first and second parallel paths for conducting load current between opposiTe main electrodes of the matrix, each of said paths including at least two of said thyristors in series; b. a resistor-inductor subcircuit connected between a juncture of adjoining thyristors in said first path and a corresponding juncture of adjoining thyristors in second path; c. first means operative to trigger one of said two thyristors in said first path and substantially simultaneously to trigger one of said two thyristors in said second path, said simultaneously triggered thyristors and said subcircuit being interconnected to form between said electrodes a circuit which conducts the initial current that flows through the matrix when said simultaneously triggered thyristors are turned on and which limits the magnitude of said initial current, said subcircuit being effective in said circuit to initially absorb and subsequently dissipate energy and to maintain sufficient voltage across the remaining thyristors of the matrix to ensure that they will commence conducting when subsequently triggered; and d. second means operative to trigger said remaining thyristors in unison after said first means operates, whereupon each of said first and second paths can conduct its proper share of the total current flowing through the matrix.

Claim 14

In a high-voltage solid-state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in first and second parallel paths for conducting load current between opposiTe main electrodes of the matrix, each of said paths including at least two of said thyristors in series; b. a resistor-inductor subcircuit connected between a juncture of adjoining thyristors in said first path and a corresponding juncture of adjoining thyristors in second path; c. first means operative to trigger one of said two thyristors in said first path and substantially simultaneously to trigger one of said two thyristors in said second path, said simultaneously triggered thyristors and said subcircuit being interconnected to form between said electrodes a circuit which conducts the initial current that flows through the matrix when said simultaneously triggered thyristors are turned on and which limits the magnitude of said initial current, said subcircuit being effective in said circuit to initially absorb and subsequently dissipate energy and to maintain sufficient voltage across the remaining thyristors of the matrix to ensure that they will commence conducting when subsequently triggered; and d. second means operative to trigger said remaining thyristors in unison after said first means operates, whereupon each of said first and second paths can conduct its proper share of the total current flowing through the matrix.

Claim 15

The switching matrix as specified in claim 10 wherein said resistor-inductor subcircuit comprises a resistor in series with an inductor.

Claim 16

The switching matrix as specified in claim 11 wherein said inductor has a saturable core.

Claim 17

The switching matrix as specified in claim 12 wherein each of said paths additionally comprises a current balancing inductor and a resistor in parallel therewith.

Claim 18

The switching matrix as claimed in claim 12 wherein said main electrodes are adapted to be connected to an alternating voltage electric power system and wherein during one cycle of said voltage said first means operates prior to said second means whereas during the next successive cycle said second means operates prior to said first means.

Claim 19

The switching matrix as specified in claim 14 wherein each of said paths additionally comprises a current balancing inductor and a resistor in parallel therewith.

Claim 20

In a high-voltage solid-state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in first and second parallel paths for conducting load current between opposite main electrodes of the matrix, each of said paths comprising a first thyristor serially connected to a second thyristor at a first point, a third thyristor serially connected to said second thyristor at a second point, and a fourth thyristor serially connected to said third thyristor at a third point; b. a resistor-inductor subcircuit connected between the first point in the first path and the first point in the second path; c. means for connecting the second point in the first path to the second point in the second path; d. another resistor-inductor subcircuit connected between the third point in the first path and the third point in the second path; e. first means operative for substantially simultaneously triggering said first and third thyristors in the first path and said second and fourth thyristors in said second path; f. second means operative to trigger, substantially in unison, said first and third thyristors in the second path and said second and fourth thyristors in the first path after said first means operates.

Claim 21

In a high-voltage solid-state electric valve, a high-current switching matrix comprising: a. a plurality of thyristors connected in first and second parallel paths for conducting load current between opposite main electrodes of the matrix, each of said paths comprising a first thyristor serially connected to a second thyristor at a first point, a third thyristor serially connected to said second thyristor at a second point, and a fourth thyristor serially connected to said third thyristor at a third point; b. a resistor-inductor subcircuit connected between the first point in the first path and the first point in the second path; c. means for connecting the second point in the first path to the second point in the second path; d. another resistor-inductor subcircuit connected between the third point in the first path and the third point in the second path; e. first means operative for substantially simultaneously triggering said first and third thyristors in the first path and said second and fourth thyristors in said second path; f. second means operative to trigger, substantially in unison, said first and third thyristors in the second path and said second and fourth thyristors in the first path after said first means operates.

Claim 22

The switching matrix as specified in claim 16 wherein each of said resistor-inductor subcircuits comprises a resistor in series with an inductor.

Claim 23

The switching matrix as specified in claim 17 wherein each inductor has a saturable core.

Claim 24

The switching matrix as specified in claim 18 wherein said saturable core inductors share a common core.

Claim 25

The switching matrix as specified in claim 18 wherein said main electrodes are adapted to be connected to an alternating voltage electric power system and wherein during one cycle of said voltage sAid first means operates prior to said second means whereas during the next successive cycle said second means operates prior to said first means.

Claim 26

The switching matrix as specified in claim 20 wherein said saturable core inductors share a common core.

Claim 27

The switching matrix as specified in claim 21 wherein current balancing inductors are provided in each of said paths and wherein resistors are provided in shunt with each of said current balancing inductors.