Zero-crossover SCR power supply regulator
AssigneeUnisys Corporation
InventorPaul Hinckley
Life of this patent
Estimating the term…
Abstract
A circuit for regulating the output of a DC power supply that substantially eliminates turn-on transients induced by the switching of a silicon-controlled rectifier (SCR). A zero-crossover detector senses the AC voltage waveform of an applied power source and provides a trigger signal at the zero-crossing point. The trigger signal is applied to cause induction of the SCR's and raise the output voltage when the power supply output drops below a regulated value, and is interrupted so as to inhibit conduction of the SCR's and decrease the output voltage when the power supply output exceeds the regulated value.
Claims11
A regulator circuit for a power supply including a silicon-controlled rectifier for developing a substantially constant transient-free DC voltate from an applied AC voltage source, comprising:
- zero-crossover circuit means responsive to cyclical variations of said AC voltage source for providing a signal indicative of the zero-crossing of one phase of said applied AC voltage source,
- switching means responsive to said zero-crossing signal and coupled to initiate conduction of said silicon-controlled rectifier substantially coincident with said zero-crossing of said applied AC voltage source,
- control logic means responsive to a DC reference potential representative of said developed DC voltage and coupled to provide an output signal to said switching means for suppressing said zero-crossing signal and thereby inhibiting conduction of said silicon-controlled rectifier when said developed DC voltage exceeds a predetermined potential and for triggering conduction of said silicon-controlled rectifier when said developed DC voltage has a value less than said predetermined potential,
- said zero-crossover circuit means further comprising:
- (1) means responsive to a transition from a first polarity of said applied AC voltage source to an opposing polarity for providing a current corresponding to at least a portion of said applied AC voltage source,
- (2) means responsive to said current corresponding to said AC voltage source for providing a pulsed signal of a predetermined polarity,
- (3) means for providing a first reference bias potential,
- (4) logic circuit means responsive to a predetermined algebraic difference of said pulsed signal and said reference bias potential for providing an output signal synchronous with said AC voltage source,
- (5) differentiating circuit means responsive to said synchronous signal for providing a differentiated output signal to further logic circuit means, and
- (6) means for providing a second reference bias potential,
- said further logic circuit means responsive to a predetermined algebraic difference of said differentiated output signal and said second reference bias potential for producing a logic signal output indicative of said zero-crossing of said one phase of said applied AC voltage source.
A zero-crossover control circuit for a polyphase power supply providing a regulated DC output voltage, comprising:
- means responsive to a transition from a first polarity of an applied AC voltage source to an opposing polarity for providing a current corresponding to at least a portion of said applied AC voltage source,
- means responsive to said current corresponding to said AC voltage source for providing a pulsed signal of a predetermined polarity,
- means for providing a first reference bias potential,
- logic circuit means responsive to a predetermined algebraic difference of said pulsed signal and said reference bias potential for providing an output signal synchronous with said AC voltage source,
- differentiating circuit means responsive to said synchronous output signal for providing a differentiated output signal to further logic circuit means, and
- means for providing a second reference bias potential,
- said further logic circuit means responsive to a predetermined algebraic difference of said differentiated output signal and said second reference bias potential for producing a logic signal output indicative of said zero-crossing of said one phase of said applied AC voltage source.
Dependencies are inferred from the claim text.