Buck-boost pulse-width-modulated line regulator

Claim 2

An AC voltage regulator for producing a predetermined magnitude AC output voltage, said regulator having input terminals for receiving an AC voltage to be regulated and output terminals to which a load is to be connected for receiving the regulator output voltage, saId regulator comprising: a transformer, having a primary winding series-connected between one terminal of the regulator input and an output terminal and having a center-tapped secondary winding, said center-tap connected to said one regulator input terminal, means for comparing the voltage at the regulator output terminals with a predetermined reference signal and for producing complementary pulse-width modulated error signals in response to said comparison which includes means for producing a square wave signal, a generator responsive to said square wave signal for producing a sawtooth voltage, a comparator for comparing said reference to said sawtooth waveform and for changing its condition in accordance therewith, and a flip-flop which is set by the comparator output and reset by the square wave signal, and complementary switch means, responsive to said pulse-width modulated error signals, a respective one of said switch means connected to a point on each side of the center tap of the secondary winding for alternately switching each said point of said secondary to a common potential point of said regulator, each connected portion of said secondary winding between a said respective point and the center tap providing a respective buck or boost voltage to said primary winding determined by the pulse widths of the error signals applied to said complementary switch means to produce a voltage correction signal across the transformer primary and to provide said predetermined output voltage to the regulator output terminals.

Claim 3

Apparatus as described in claim 1 wherein said means for developing a square wave signal is an astable multivibrator.

Claim 4

An AC voltage regulator for producing predetermined magnitude AC output voltage, said regulator having input terminals for receiving an AC voltage to be regulated and output terminals to which a load is to be connected for receiving the regulator output voltage, said regulator comprising: a transformer, having a primary winding series-connected between one terminal of the regulator input and an output terminal and having a center-tapped secondary winding, said center-tap connected to said one regulator input terminal, means for comparing the voltage at the regulator output terminals with a predetermined reference signal and for producing pulse-width modulated error signals which includes means for producing a square wave signal, a comparator for comparing said reference to said output voltage, a phase shifter, responsive to said square wave signal and comparator output, for phase shifting said signal in accordance with the magnitude of said comparator output, and a flip-flop which is set by said square wave signal and reset by said phase shifted signal, and complementary switch means, responsive to said pulse-width modulated error signals, a respective one of said switch means connected to a point on each side of the center tap of the secondary winding for alternately switching each said point of said secondary to a common potential point of said regulator, each connected portion of said secondary winding between a said respective point and the center tap providing a respective buck or boost voltage to said primary winding determined by the pulse widths of the error signals applied to said complementary switch means to produce a voltage correction signal across the transformer primary and provide said predetermined output voltage to the regulator output terminals.

Claim 5

An AC voltage regulator for producing predetermined magnitude AC output voltage, said regulator having input terminals for receiving an AC voltage to be regulated and output terminals to which a load is to be connected for receiving the regulator output voltage, said regulator comprising: a transformer, having a primary winding series-connected between one terminal of the regulator input and an output terminal and having a center-tapped secondary winding, said center-tap connected to said one regulator input terminal, means for comparing the voltage at the regulator output terminals with a predetermined reference signal and for producing pulse-width modulated error signals which includes means for producing a square wave signal, a comparator for comparing said reference to said output voltage, a phase shifter, responsive to said square wave signal and comparator output, for phase shifting said signal in accordance with the magnitude of said comparator output, and a flip-flop which is set by said square wave signal and reset by said phase shifted signal, and complementary switch means, responsive to said pulse-width modulated error signals, a respective one of said switch means connected to a point on each side of the center tap of the secondary winding for alternately switching each said point of said secondary to a common potential point of said regulator, each connected portion of said secondary winding between a said respective point and the center tap providing a respective buck or boost voltage to said primary winding determined by the pulse widths of the error signals applied to said complementary switch means to produce a voltage correction signal across the transformer primary and provide said predetermined output voltage to the regulator output terminals.

Claim 6

Apparatus as described in claim 3 wherein said reference is a DC source and said output voltage is connected to means for converting said output to a DC signal representing the magnitude of said output voltage to which said comparator is responsive.

Claim 7

An AC voltage regulator for producing a predetermined magnitude AC output voltage, said regulator having input terminals for receiving an AC voltage to be regulated and output terminals to which a load is to be connected for receiving the regulator output voltage, said regulatOr comprising: a transformer, having a primary winding series-connected connected between one terminal of the regulator input and an output terminal and having a center-tapped secondary winding, said center-tap connected to said one regulator input terminal, means for comparing the voltage at the regulator output terminals with a predetermined reference signal and for producing complementary pulse-width modulated error signals in response to said comparison, complementary switch means comprising a pair of diode bridges each of which is switched by a respective transistor responsive to said pulse-width modulated error signals, a respective one of said switch means connected to a point on each side of the center tap of the secondary winding for alternately switching each said point of said secondary to a common potential point of said regulator, each connected portion of said secondary winding between a said respective point and the center tap providing a respective buck or boost voltage to said primary winding determined by the pulse widths of the error signals applied to said complementary switch means to produce a voltage correction signal across the transformer primary and provide said predetermined output voltage to the regulator output terminals, transformer means having a full wave rectifier in the secondary thereof for controlling the conduction of a transistor, and means for driving said transformer means including means for converting said pulse-width modulated error signals to trilevel pulse-width modulated signals wherein said means includes means for phase-shifting said pulse-width modulated signal a predetermined amount, means responsive to said phase-shifted signal for inverting said signal, and means for summing said inverted signal with said original pulse-width modulated signal to produce a trilevel pulse-width modulated signal.

Claim 8

An AC voltage regulator for producing a predetermined magnitude AC output voltage, said regulator having input terminals for receiving an AC voltage to be regulated and output terminals to which a load is to be connected for receiving the regulator output voltage, said regulatOr comprising: a transformer, having a primary winding series-connected connected between one terminal of the regulator input and an output terminal and having a center-tapped secondary winding, said center-tap connected to said one regulator input terminal, means for comparing the voltage at the regulator output terminals with a predetermined reference signal and for producing complementary pulse-width modulated error signals in response to said comparison, complementary switch means comprising a pair of diode bridges each of which is switched by a respective transistor responsive to said pulse-width modulated error signals, a respective one of said switch means connected to a point on each side of the center tap of the secondary winding for alternately switching each said point of said secondary to a common potential point of said regulator, each connected portion of said secondary winding between a said respective point and the center tap providing a respective buck or boost voltage to said primary winding determined by the pulse widths of the error signals applied to said complementary switch means to produce a voltage correction signal across the transformer primary and provide said predetermined output voltage to the regulator output terminals, transformer means having a full wave rectifier in the secondary thereof for controlling the conduction of a transistor, and means for driving said transformer means including means for converting said pulse-width modulated error signals to trilevel pulse-width modulated signals wherein said means includes means for phase-shifting said pulse-width modulated signal a predetermined amount, means responsive to said phase-shifted signal for inverting said signal, and means for summing said inverted signal with said original pulse-width modulated signal to produce a trilevel pulse-width modulated signal.