US3621373A — Transient-free solid-state power contactor

Claim 1

Independent Claim 306 words

A power contactor for controlling the application of an alternating current power source between an input terminal and an output terminal comprising a silicon controlled rectifier member comprising an anode electrode and cathode electrode and a control electrode, means for applying said power source across the anodeto-cathode junction of said rectifier element, means for detecting the zero crossovers of said power source, means receiving the output from said zero-crossing detection means and being responsive to successive ones of the positive-going zero crossovers of said power source to initiate a ramplike control signal having essentially linear voltage rise between substantially zero volts and a predetermined maximum control voltage magnitude, said maximum control voltage magnitude being attained at the time occurrence of negative going zero crossovers of said power source, means for generating a selectively variable reference voltage, said reference voltage varying between a predetermined maximum voltage in excess of said maximum control voltage to a substantially zero voltage level during the time period defined by successive ones of the positive going halfcycles of said power source, current impulse generating means, said current impulse generating means receiving said reference and control voltages as respective inputs thereto and being adapted to generate an impulse at those times during successive ones of the positive half-cycles of said power source when said reference voltage falls to a value less than that of said control voltage, and means responsive to said current impulses for gating said silicon controlled rectifier element into conduction at the time occurrence of successive ones of said current impulses, whereby the conduction angle of said silicon controlled rectifier is progressively decreased during the time occurrence of successive ones of the positive half-cycles of said power source and predetermined greater portions of the successive ones of the positive half-cycles of said power source are switched to said output terminal.

Claim 2

Dependent Claim 306 words

A power contactor for controlling the application of an alternating current power source between an input terminal and an output terminal comprising a silicon controlled rectifier member comprising an anode electrode and cathode electrode and a control electrode, means for applying said power source across the anodeto-cathode junction of said rectifier element, means for detecting the zero crossovers of said power source, means receiving the output from said zero-crossing detection means and being responsive to successive ones of the positive-going zero crossovers of said power source to initiate a ramplike control signal having essentially linear voltage rise between substantially zero volts and a predetermined maximum control voltage magnitude, said maximum control voltage magnitude being attained at the time occurrence of negative going zero crossovers of said power source, means for generating a selectively variable reference voltage, said reference voltage varying between a predetermined maximum voltage in excess of said maximum control voltage to a substantially zero voltage level during the time period defined by successive ones of the positive going halfcycles of said power source, current impulse generating means, said current impulse generating means receiving said reference and control voltages as respective inputs thereto and being adapted to generate an impulse at those times during successive ones of the positive half-cycles of said power source when said reference voltage falls to a value less than that of said control voltage, and means responsive to said current impulses for gating said silicon controlled rectifier element into conduction at the time occurrence of successive ones of said current impulses, whereby the conduction angle of said silicon controlled rectifier is progressively decreased during the time occurrence of successive ones of the positive half-cycles of said power source and predetermined greater portions of the successive ones of the positive half-cycles of said power source are switched to said output terminal.

Claim 3

Dependent Claim 92 words

Means as defined in claim 1 wherein said current impulse generating means comprises a differential amplifier to which said reference and control voltages are applied as respective first and second inputs, said differential amplifier being adapted to switch from a first saturation voltage level to a second and oppositely polarized saturation voltage level when said control voltage input crosses over the instantaneous magnitude of reference voltage input applied thereto, and output means associated with said differential amplifier to generate a current impulse in response to said aforedefined differential amplifier input voltage crossover.

Claim 4

Dependent Claim 80 words

Means as defined in claim 2 wherein the current impulse output from said differential amplifier output means is supplied as triggering input to a blocking oscillator, the output from said blocking oscillator comprising a pulse of predetermined width the time occurrence of which is coincident with that of said current impulse, the output from said blocking oscillator being applied between the control and cathode electrode of said silicon controlled rectifier to comprise a gating impulse for said silicon controlled rectifier.

Claim 5

Dependent Claim 55 words

Means as defined in claim 3 wherein said reference voltage generation means comprises a capacitor the voltage across which comprises said reference voltage, a reference voltage source the magnitude of which comprises said maximum reference voltage magnitude, and means for selectively applying said reference voltage source through resistive means to charge and discharge said capacitor.

Claim 6

Dependent Claim 228 words

Means as defined in claim 3 wherein said reference voltage generation means comprises a reference source voltage the magnitude of which exceeds said maximum control voltage magnitude, a transistor switching means, a reference voltage output terminal, said reference voltage source being connected through the emitter-collector junction of said transistor switching means to said output terminal, RC time constant means, said reference voltage source being additionally connected through said RC time constant means to said reference to said reference voltage output terminal, means for applying first and second logic voltage levels to the base electrode of said transistor switching means, said transistor means being responsive to a first one of said logic voltage levels to render said transistor switching means conductive to effect a low impedance path between said reference voltage source and said reference voltage output terminal, said transistor switching means being responsive to the second one of said logic voltage levels to render said transistor switching means nonconductive whereby the voltage on said reference voltage output terminal varies between a maximum value defined by said reference voltage source and a value substantially equal to zero volts at a rate determined by said RC time constant means, said first logic voltage level being effected in response to an ''''OFF'''' command being initiated, and said second logic voltage level being effected in response to an ''''ON'''' command being initiated.

Claim 7

Dependent Claim 291 words

A multiphase power contractor for control switching of a multiphase power source between multiphase input terminals and respective primary windings of a muhtiphase power transformer primary winding comprising a plurality of switching control means each of which is associated with one of said power source input lines; each of said switching control means comprising a silicon controlled rectifier element serially connected between the associated one of said power source input lines and associated one of said power transformer primary windings, a plurality of switching control means respective ones of which are associated with the silicon controlled rectifier in each of said lines, each of said plurality of switching control means comprising means responsive to successive ones of the positive going zero crossovers of the applied power source phase to initiate a ramplike control signal varying between substantially zero volts and a predetermined maximum control voltage magnitude at the duration of the ensuing half-cycle of the applied power source phase, a source of reference voltage variable between a maximum reference voltage in excess of said maximum control voltage level during the time period defined by successive one of the positive going half-cycles of the applied power source phase, current impulse generating means receiving said control and reference voltages and being responsive thereto to generate a current impulse during successive ones of the positive half-cycles of said applied power source phase when said reference voltage falls beneath said control voltage; said source of reference voltage comprising a a common reference voltage source generating means the Output of which is applied to each of said plurality of switching control means, and the cathode-to-anode junction of each said silicon controlled rectifier element being shunted with an oppositely polarized one of a plurality of diode members.

Claim 8

Dependent Claim 291 words

A multiphase power contractor for control switching of a multiphase power source between multiphase input terminals and respective primary windings of a muhtiphase power transformer primary winding comprising a plurality of switching control means each of which is associated with one of said power source input lines; each of said switching control means comprising a silicon controlled rectifier element serially connected between the associated one of said power source input lines and associated one of said power transformer primary windings, a plurality of switching control means respective ones of which are associated with the silicon controlled rectifier in each of said lines, each of said plurality of switching control means comprising means responsive to successive ones of the positive going zero crossovers of the applied power source phase to initiate a ramplike control signal varying between substantially zero volts and a predetermined maximum control voltage magnitude at the duration of the ensuing half-cycle of the applied power source phase, a source of reference voltage variable between a maximum reference voltage in excess of said maximum control voltage level during the time period defined by successive one of the positive going half-cycles of the applied power source phase, current impulse generating means receiving said control and reference voltages and being responsive thereto to generate a current impulse during successive ones of the positive half-cycles of said applied power source phase when said reference voltage falls beneath said control voltage; said source of reference voltage comprising a a common reference voltage source generating means the Output of which is applied to each of said plurality of switching control means, and the cathode-to-anode junction of each said silicon controlled rectifier element being shunted with an oppositely polarized one of a plurality of diode members.

Claim 9

Dependent Claim 73 words

Means as defined in claim 6 further comprising a resistive member through which said reference voltage is serially applied in common to said plurality of switching control means and a capacitor through with the reference voltage as applied through said resistive member is shunted to system ground, whereby high-frequency transients appearing on the output of said reference voltage generating means are rendered ineffective in initiating a gating influence on said silicon controlled rectifier.

Claim 10

Dependent Claim 55 words

Means as defined in claim 6 wherein said reference voltage generation means comprises a capacitor the voltage across which comprises said reference voltage, a reference voltage source the magnitude of which comprises said maximum reference voltage magnitude, and means for selectively applying said reference voltage source through resistive means to charge and discharge said capacitor.

Claim 11

Dependent Claim 226 words

Means as defined in claim 6 wherein said reference voltage generation means comprises a reference source voltage the magnitude of which exceeds said maximum control voltage magnitude, a transistor switching means, a reference voltage output terminal, said reference voltage source being connected through the emitter-collector junction of said transistor switching means to said output terminal, RC time constant means, said reference voltage source being additionally connected through said RC time constant means to said reference voltage output terminal, means for applying first and second logic voltage levels to the base electrode of said transistor switching means, said transistor switching means being responsive to a first one of said logic voltage levels to render said transistor switching means conductive to effect a low impedance path between said reference voltage source and said reference voltage output terminal, said transistor switching means being responsive to the second one of said logic voltage levels to render said transistor switching means nonconductive whereby the voltage on said reference voltage output terminal varies between a maximum value defined by said reference voltage source and a value substantially equal to zero volts at a rate determined by said RC time constant means, said first logic voltage level being effected in response to an ''''OFF'''' command being initiated, and said second logic voltage level being effected in response to an ''''ON'''' command being initiated.

Claim 12

Dependent Claim 93 words

Means as defined in claim 7 wherein said current impulse generating means comprise a differential amplifier to which said reference and control voltages are applied as respective first and second inputs, said differential amplifier being adapted to switch from a first saturation voltage level to a second and oppositely polarized saturation voltage level when said control voltage input crosses over the instantaneous magnitude of the reference voltage input applied thereto, and output means associated with said differential amplifier to generate a current impulse in response to said aforedefined differential amplifier input voltage crossover.

Claim 13

Dependent Claim 81 words

Means as defined in claim 8 wherein said current impulse generating means comprise a differential amplifier to which said reference and control voltages are applied as respective first and second inputs, said differential amplifier being adapted to switch from a first saturation voltage level to a second and oppositely polarized saturation voltage level when said control voltage input crosses over the instantaneous magnitude of the reference voltage input applied thereto, and output means associated with said differential amplifier input voltage crossover.

Claim 14

Dependent Claim 93 words

Means as defined in claim 9 wherein said current impulse generating means comprises a differential amplifier to which said reference and coNtrol voltages are applied as respective first and second inputs, said differential amplifier being adapted to switch from a first saturation voltage level to a second and oppositely polarized saturation voltage level when said control voltage input crosses over the instantaneous magnitude of the reference voltage input applied thereto, and output means associated with said differential amplifier to generate a current impulse in response to said aforedefined differential amplifier input voltage crossover.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1974-11-15	1975-05-17	1975-11-16	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1978-11-15	1979-05-17	1979-11-16	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1982-11-15	1983-05-17	1983-11-16	$7700.00	Window Closed / Lapsed

Transient-free solid-state power contactor

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