Power converter apparatus and silicon controlled rectifier switching circuit therefor

Claim 2

A converter for converting a d.c. input voltage to an a.c. or d.c. output voltage comprising input terminals adapted to be connected to receive said input voltage and output terminals adapted to connect said output voltage to a load, at least one programmed current switch connected between said input and output terminals, said switch being responsive to control signals to switch the current applied to said load whereby to provide a pulse width modulated voltage to said load, said programmed current switch including a series pass silicon controlled rectifier, an inductor in series with said series pass silicon controlled rectifier, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said series pass silicon controlled rectifier to extinguish the rectifier and provide current in excess of said load current, uni-directional current control means connected to conduct current in excess of load current from the output terminals to the input terminals of said converter and means for conducting load current after turn-off of said series pass silicon controlled rectifier.

Claim 3

A converter as in claim 1 wherein said means for back biasing said silicon controlled rectifier comprises a series branch including a commutating silicon controlled rectifier, an inductor and a capacitor.

Claim 4

A converter as in claim 2 including means for resetting said commutating silicon controlled rectifier.

Claim 5

A converter as in claim 3 wherein said resetting means includes a silicon controlled rectifier.

Claim 6

A converter comprising an output transformer having a primary winding with first and second terminals and a center tap terminal, said center tap terminal adapted to be connected to one terminal of an associated d.c. power source having one and another terminal, a programmed current switch having a terminal connected to one terminal of the primary winding and another terminal adapted to be connected to the another terminal of said d.c. power source and a rectifier having one terminal connected to the other terminal of said primary winding and another terminal adapted to be connected to said d.c. power source, said program current switch including a series pass silicon controlled rectifier connected to said d.c. power source and adapted to be turned on to conduct current between said transformer primary center tap and said first terminal, an inductor in series with said silicon controlled rectifier connected to the one terminal, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said silicon controlled rectifier to extinguish the silicon controlled rectifier and provide current in excess of the load current and stop the conduction of current through said silicon controlled rectifier, and a diode connected across said silicon controlled rectifier and inductor to conduct said excess current, said rectifier serving to alternately conduct current between said transformer primary center tap and the second terminal.

Claim 7

A converter comprising an output transformer having a primary winding with first and second terminals and a center tap terminal, said center tap terminal adapted to be connected to one terminal of an associated d.c. power source having one and another terminal, a programmed current switch having a terminal connected to one terminal of the primary winding and another terminal adapted to be connected to the another terminal of said d.c. power source and a rectifier having one terminal connected to the other terminal of said primary winding and another terminal adapted to be connected to said d.c. power source, said program current switch including a series pass silicon controlled rectifier connected to said d.c. power source and adapted to be turned on to conduct current between said transformer primary center tap and said first terminal, an inductor in series with said silicon controlled rectifier connected to the one terminal, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said silicon controlled rectifier to extinguish the silicon controlled rectifier and provide current in excess of the load current and stop the conduction of current through said silicon controlled rectifier, and a diode connected across said silicon controlled rectifier and inductor to conduct said excess current, said rectifier serving to alternately conduct current between said transformer primary center tap and the second terminal.

Claim 8

A converter comprising a plurality of circuits each including an output transformer having a primary winding with first and second terminals and a center tap terminal and a secondary winding, said center tap terminal adapted to be connected to one terminal of an associated d.c. power source, a programmed current switch having a terminal connected to one terminal of the primary winding and another terminal adapted to be connected to the other terminal of said d.c. power source and a rectifier having one terminal connected to the other terminal of said primary winding and another terminal adapted to be connected to the other terminal of said d.c. power soUrce, said program current switch including a series pass silicon controlled rectifier adapted to be turned on to conduct current between said transformer primary center tap and said one terminal, an inductor in series with said silicon controlled rectifier, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said silicon controlled rectifier to extinguish the silicon controlled rectifier and stop the conduction of current through said silicon controlled rectifier, said rectifier serving to alternately conduct current between said transformer primary center tap and the other terminal, said center tap terminals of said transformers being connected to one another and said another terminal of said programmed current switch and of said rectifier being connected to one another and to said other terminal of said d.c. power source, said secondary windings being interconnected to supply output power.

Claim 9

A converter comprising a plurality of circuits each including an output transformer having a primary winding with first and second terminals and a center tap terminal and a secondary winding, said center tap terminal adapted to be connected to one terminal of an associated d.c. power source, a programmed current switch having a terminal connected to one terminal of the primary winding and another terminal adapted to be connected to the other terminal of said d.c. power source and a rectifier having one terminal connected to the other terminal of said primary winding and another terminal adapted to be connected to the other terminal of said d.c. power soUrce, said program current switch including a series pass silicon controlled rectifier adapted to be turned on to conduct current between said transformer primary center tap and said one terminal, an inductor in series with said silicon controlled rectifier, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said silicon controlled rectifier to extinguish the silicon controlled rectifier and stop the conduction of current through said silicon controlled rectifier, said rectifier serving to alternately conduct current between said transformer primary center tap and the other terminal, said center tap terminals of said transformers being connected to one another and said another terminal of said programmed current switch and of said rectifier being connected to one another and to said other terminal of said d.c. power source, said secondary windings being interconnected to supply output power.

Claim 10

A converter as in claim 5 including uni-directional current control means connected to conduct excess load currents from said one transformer primary terminal to the another terminal of said d.c. power source.

Claim 11

A converter comprising an output transformer having a primary winding having a center tap and first and second terminals, said center tap terminal being adapted to be connected to one terminal of a d.c. power source, first and second programmed current switch means having one terminal connected to said first transformer terminal and a second terminal adapted to be connected to said d.c. source, second programmed current switch means having one terminal connected to the second transformer terminal and a second terminal adapted to be connected to said d.c. source, first and second diode means connected in parallel with said second and first programmed switch means respectively to alternately provide current paths for said first and second programmed switches, said programmed switches comprising a series pass silicon controlled rectifier, an inductor in series with said series pass silicon controlled rectifier, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said series pass controlled rectifier to extinguish it and provide current in excess of the load current and uni-directional current control means connected to conduct excess load currents from said output terminals to the input terminals of said converter.

Claim 12

A converter comprising an output transformer having a primary winding having a center tap and first and second terminals, said center tap terminal being adapted to be connected to one terminal of a d.c. power source, first and second programmed current switch means having one terminal connected to said first transformer terminal and a second terminal adapted to be connected to said d.c. source, second programmed current switch means having one terminal connected to the second transformer terminal and a second terminal adapted to be connected to said d.c. source, first and second diode means connected in parallel with said second and first programmed switch means respectively to alternately provide current paths for said first and second programmed switches, said programmed switches comprising a series pass silicon controlled rectifier, an inductor in series with said series pass silicon controlled rectifier, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said series pass controlled rectifier to extinguish it and provide current in excess of the load current and uni-directional current control means connected to conduct excess load currents from said output terminals to the input terminals of said converter.

Claim 13

A converter comprising first and second input terminals, a programmed current switch connected between said first input terminal and an output load terminal, and a second programmed current switch connected between the second input terminal and said output load terminal, said first and second programmed current switches each including a series pass silicon controlled rectifier, an inductor in series with said series pass silicon controlled rectifier, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said series pass silicon controlled rectifier to extinguish it and provide current in excess of said load current, first and second unidirectional current control means connected across said first and second switches to conduct current in excess of load currents from the output of each switch to the input terminals, and first and second means for conducting load currents after turn-off of said series pass silicon controlled rectifiers connected between the input terminal of said first and second programmed current switches and the output terminal of said second and first programmed current switches respectively.

Claim 14

A converter comprising first and second input terminals, a programmed current switch connected between said first input terminal and an output load terminal, and a second programmed current switch connected between the second input terminal and said output load terminal, said first and second programmed current switches each including a series pass silicon controlled rectifier, an inductor in series with said series pass silicon controlled rectifier, means responsive to a turn-off signal connected across said silicon controlled rectifier for applying a high back bias voltage to said series pass silicon controlled rectifier to extinguish it and provide current in excess of said load current, first and second unidirectional current control means connected across said first and second switches to conduct current in excess of load currents from the output of each switch to the input terminals, and first and second means for conducting load currents after turn-off of said series pass silicon controlled rectifiers connected between the input terminal of said first and second programmed current switches and the output terminal of said second and first programmed current switches respectively.

Claim 15

A converter as in claim 9 wherein said means for back biasing said silicon controlled rectifier comprises a series branch including a commutating silicon controlled rectifier, an inductor and a capacitor.

Claim 16

A converter as in claim 10 including means for resetting said commutating silicon controlled recTifier.

Claim 17

A converter as in claim 11 wherein said resetting means includes a silicon controlled rectifier.

Claim 18

A converter as in claim 12 including means for controlling the di/dt turn-on and means for controlling dv/dt upon reapplication of forward voltage to said silicon controlled rectifiers.

Claim 19

A converter as in claim 9 including a transformer connected between the load and the output terminals of said programmed current switches.

Claim 20

A converter as in claim 14 wherein said transformer comprises an autotransformer.

Claim 21

Apparatus comprising at least first and second converters each comprising first and second input terminals, a programmed current switch having first and second terminals connected between said first input terminal and an output load terminal respectively, and a second programmed current switch having first and second terminals connected between the second input terminal and said output load terminal, said first and second programmed current switches including a series pass silicon controlled rectifier, an inductor in series with said series pass silicon controlled rectifier, means responsive to a turn-off signal connected across said series pass silicon controlled rectifier for applying a high back bias voltage to said series pass silicon controlled rectifier to extinguish it and provide current in excess of load current, first and second uni-directional current control means connected across said first and second programmed current switches to conduct current in excess of load currents from the output of the switches to the input, and first and second means for conducting load currents after turn-off of said series pass silicon controlled rectifiers connected between the first terminal of said first and second programmed current switches and the second terminal of said second and first programmed current switches respectively, and a load connected between the output load terminal of said first and second converters.

Claim 22

Apparatus comprising at least first and second converters each comprising first and second input terminals, a programmed current switch having first and second terminals connected between said first input terminal and an output load terminal respectively, and a second programmed current switch having first and second terminals connected between the second input terminal and said output load terminal, said first and second programmed current switches including a series pass silicon controlled rectifier, an inductor in series with said series pass silicon controlled rectifier, means responsive to a turn-off signal connected across said series pass silicon controlled rectifier for applying a high back bias voltage to said series pass silicon controlled rectifier to extinguish it and provide current in excess of load current, first and second uni-directional current control means connected across said first and second programmed current switches to conduct current in excess of load currents from the output of the switches to the input, and first and second means for conducting load currents after turn-off of said series pass silicon controlled rectifiers connected between the first terminal of said first and second programmed current switches and the second terminal of said second and first programmed current switches respectively, and a load connected between the output load terminal of said first and second converters.

Claim 23

A converter as in claim 16 including a transformer connected between the load and the second terminal of the programmed current switches of each of said converters.

Claim 24

A converter as in claim 17 wherein said transformer comprises an autotransformer.

Claim 25

Apparatus as in claim 12 including means for receiving said d.c. input voltage and integrating the voltage, comparison means for comparing said voltage with a reference voltage corresponding to the desired output and provide a control signal and means responsive to the control signal for generating firing voltages for said silicon controlled rectifiers to provide a desired output voltage.

Claim 26

Apparatus as in claim 4 including means for receiving said d.c. input voltage and integrating the voltage, comparison means for comparing said voltage with a reference voltage corresponding to the desired output and provide a control signal and means responsive to the control signal for generating firing voltages for said silicon controlled rectifiers to provide a desired output voltage.