Showing papers on "Voltage regulation published in 1972"

Switching regulator sweep starting protection circuit

Abstract: An overload protection system for a switching power supply includes a variable rate and variable pulse duration drive source for operating the switching transistor. Upon turn-on of the power supply, the switching transistor is driven with low repetition rate pulses having a predetermined time duration. The rate is gradually increased to a normal operating rate to minimize turnon transients. Load sensing circuitry is used in conjunction with the variable rate drive source to cause the drive source to operate at the low rate in the event that an overload is applied to the power supply, and to turn off the drive source if the overload persists. Circuitry for providing automatic reset following an overload is employed. A feedback circuit is used to vary the duration of the drive pulses to provide automatic voltage regulation.

Dc-to-dc converter having soft start and other regulation features employing priority of pulse feedback

Abstract: There is disclosed a dc-to-dc converter provided with dual-mode current and voltage regulation and a "soft" start characteristic in which a digital-type feedback control is obtained based upon the relative priority of the arrival of the respective feedback pulses at the driving circuit for the converter transistors. In addition, a shut-down circuit checks both of two redundant feedback circuits for the absence of feedback pulses for a prescribed time before triggering shutdown. Either of the two redundant feedback circuits is individually capable of regulating the output voltage or the output current if the output load is balanced. With a high impedance unbalanced load, the voltage regulator on the output lead that tends to experience high voltage takes control and limits the maximum output voltage.

Voltage control of an a.c. drive system during motor starting

Abstract: Method and apparatus for providing adequate breakaway torque for the a-c motors being started in a system in which a source of adjustable voltage a-c electric power such as an inverter supplies electric power to the motors being started. The output voltage of the source is substantially increased in a non-abrupt manner for an initial predetermined starting period to provide adequate break-away torque, the voltage thereafter being reduced to a level corresponding to a predetermined desired constant ratio relative to output frequency.

High and low voltage regulating circuit

Abstract: A circuit is provided in which current pulses through a first semi-conductor device and through one winding of a transformer generate high voltage and low voltage pulses in two other windings. Rectifiers are connected to the latter two windings to produce high direct voltage and low direct voltage. A semi-conductor control device is connected to the high voltage rectifier circuit to respond to changes in the high voltage and is connected to the control device to adjust its output impedance as necessary to cause the amplitude of pulses applied to the transformer to increase when the high direct voltage tends to drop, thereby keeping the high voltage constant. However, in order to keep the magnitude of the low direct voltage from changing in response to changes in the pulse amplitude, the control semi-conductor is connected to the low voltage rectifier circuit to provide a compensating direct voltage.

Automatic voltage regulator with optical feedback

Abstract: An automatic voltage regulator employing an optical feedback system, in which a luminous element, whose intensity varies in response to the variation in a regulated voltage, illuminates a photosensitive element which generates a feedback signal responsive to intensity of light. More precise voltage regulation is possible. Furthermore, a "soft-start" circuit is provided which can arbitrarily select a rising time of a regulated voltage to a predetermined magnitude, starting always from a predetermined phase angle of the voltage.

Supply system having short-circuit voltage regulation

Abstract: A first thyristor switch is turned on to supply charging current to the storage member until it is charged to a high predetermined or regulated voltage. When this voltage is reached, the first switch is turned off, and a second thyristor switch, connected across the storage member, is turned on to short-circuit the supply system. A voltage-limiting circuit keeps the voltage across the second switch to a value well below the high regulated voltage of the storage member.

Voltage regulating system for vehicle generators

Abstract: A voltage regulating system for vehicle generators of the type in which a voltage across the terminals of a battery is detected to thereby effect on-off control of the field current of an alternator for charging the battery in accordance with the detected voltage. The voltage regulating system includes a voltage control circuit for detecting the terminal voltage of the battery to effect on-off control of the field current, the on-off control action of said voltage control circuit having a hysteresis characteristic, and an astable multivibrator circuit connected to said voltage control circuit, whereby the duration of flow of the field current is always limited to less than one oscillation period of said multivibrator circuit, thereby effectively preventing oscillation from being caused in said voltage control circuit.

Circuit for converting dc voltage into three-phase voltage

Abstract: A circuit for converting a DC voltage or a three-phase voltage of variable or constant frequency into a three-phase voltage of a constant other frequency utilizes an intermediate circuit frequency converter. The converter comprises two three-phase thyristor inverters, connected in parallel at the input side. The three-phase outputs of the one three-phase thyristor inverters are connected together via voltage divider chokes. The taps of the voltage divider chokes provide the three outputs of the converter.

Monitoring apparatus for preventing spark-overs at a high voltage installation

Abstract: A monitoring apparatus for preventing a spark-over at a high voltage installation for corona electrodes comprising a high-frequency voltage source and a high voltage transformer, the secondary winding of which is coupled through the agency of a high voltage cascade with the corona electrode. The high-frequency voltage source is connected via a power amplifier, which starting from a certain value of its output current exhibits current limiting and decreasing output voltage characteristics, with the primary winding of the high voltage transformer. A comparator has its inputs coupled with the input and output respectively of the power amplifier and in the event the output voltage of the power amplifier is smaller than its input voltage interrupts the current circuit to the corona electrode through the agency of a cutoff mechanism.

Adjustable high voltage power supply with output polarity switching

Abstract: There is provided a high voltage power supply utilizing a high leakage reactance transformer connected to a voltage doubler which has a capability of reversing its output voltage. The power supply is of a type which may be used at several different input frequencies. There is provided an inexpensive low voltage switch connected to the secondary winding of the transformer and to ground. The low voltage switch is used to switch from one number of turns to another number of turns on the secondary winding depending on the frequency of the input signal.

Micro-miniature high efficiency power supply

Abstract: A micro-miniaturized high efficiency power supply utilizing the principle of open loop voltage regulation. The circuit employs full-wave rectification at the input followed by filtering, preregulation, inverter isolation and final saturated series regulation with noise suppression and energy storage filters at appropriate strategic places. A hold up circuit initially supplies power to control circuitry. When a pre-regulator attains a predetermined value the hold up circuit is turned off and a pre-regulator then supplies power to the control circuitry.

Load balancing voltage regulator

Abstract: A voltage regulator is disclosed which includes circuitry therein which may be interconnected with other regulators for machines operating in parallel to provide interaction between the coupled regulators to increase the output of the lower generating machine to match the higher output machine. The regulator includes a voltage sensing network whose output controls a power transistor in series with the field excitation to inversely regulate the field excitation in accordance with the output voltage of the generator. Each regulator further includes a voltage divider network connected between the field excitations of each regulator which network is responsive to the presence of greater excitation in the other regulators to vary the voltage sensing network in the one regulator to increase field excitation to achieve load balance.

Low voltage appliance protector

Abstract: A method and apparatus for disconnecting a load from a power source when the voltage from the power source falls below a first predetermined level and for reconnecting the load to the power source when the voltage rises above a second predetermined level. The voltage of the power source is constantly sensed and when the voltage falls below a first predetermined level a switch means, which is connected between the power source and the load, is opened, thereby disconnecting the load from the power source. An auxiliary coil is placed in series with the load so that, when a load drawing an initially large current is connected to the power source, the increased current through the auxiliary coil produces a magnetic force to hold the switch means closed even though a voltage below the first predetermined level is sensed. In this manner, false disconnection of the load from the power source is prevented.

Multiple input voltage source power supply

Abstract: A power supply for supplying a predetermined d.c. output voltage notwithstanding its connection to external a.c. voltage sources of different voltage magnitudes operates in either a full wave rectifying or diode ridge rectifying mode to accommodate the different source voltage. A zener diode senses the source voltage magnitude and a mode control voltage controls a switching circuit for establishing the power supply in the proper rectifying mode.

Synthesis of optimal regulator for synchronous machine

Abstract: A procedure for the synthesis of a self-adaptive near-optimal controller for small perturbations, subject to a quadratic performance index, of a synchronous generator connected to an infinite busbar is described. The performance of the system with this controller is compared with those having proportional and derivative voltage regulators. The optimal controller extends the stable operating region of the system at low active-power levels, increases the magnitudes of perturbations for which the actual nonlinear system is stable, improves the transient response and reduces the steady-state deviations for a step change in the infinite-busbar voltage.

Compensation equipment for fluctuations in a.c. source voltage

Abstract: An AC voltage regulator which detects the instantaneous supply voltage in a phase shifter and compares it with the reference voltage by a comparator circuit so that in response to the output signals from the comparator, the firing angle of the thyristors connected to a supply voltage circuit may be controlled in order to maintain constant the effective load current.

Electrical power monitor

Abstract: In a monitor for determining the real electrical power being delivered by a 3-phase source to a load, each phase voltage and a voltage which is proportional to and in phase with the corresponding line current are coupled to separate balanced detectors Each detector provides a DC voltage which is proportional to the real power being delivered by its corresponding phase The DC voltages from the balanced detectors are connected in series and the resulting sum voltage is coupled to a plurality of voltage comparators Each voltage comparator provides a signal when the sum voltage exceeds a predetermined magnitude and each of the voltage comparators is set to respond to a different sum voltage magnitude Since the sum voltage is proportional to the real power being delivered by the source, within the range of voltage magnitudes set, the output signals of the voltage comparators provide a measure of the power being delivered by the 3-phase source A binary output means, such as a relay, is controlled by each comparator

Vector addition sine wave power control using single inverter and return of energy to inverter source

Abstract: An alternating current power supply control circuit utilizing a single sine wave inverter having a sine wave output which is derived from a DC source which presents a constant voltage to a load, is coupled to an unregulated AC supply voltage to add or subtract therefrom an incremental voltage required for regulation of the AC supply voltage. Unwanted or excess energy in the inverter is returned to the DC source to conserve power and prevent voltage build up in the inverter. The resultant output voltage which, if desired, may be converted by rectification to DC is compared with a desired voltage reference to generate an error signal to control the relative phase of the sine wave output of the inverter with respect to the phase of the supply voltage to achieve a regulated power supply.

Output voltage adjusting circuit

Abstract: A circuit connectible to an integrated circuit fixed voltage D.C. regulator for providing an adjustable value of output voltage to a load, especially a load consisting of an incandescent lamp.

Low harmonic telephone ringing generator

Abstract: A ringing generator for telephone communication systems having output voltage and frequency regulation. A pair of transistor amplifiers in connection with a plural winding output transformer convert battery voltage to a sinusoidal ringing signal, a feedback signal being derived from a further winding of the output transformer providing output voltage regulation. A further pair of transistors provide variable shunting of the signal applied to the transistor amplifiers for current limiting control.

Power supply utilizing improved voltage regulation

Abstract: A high efficiency, AC-to-DC power supply is provided in which a preregulator circuit including a rectifier bridge is coupled to an AC supply input. Two switching rectifiers, one in each of two arms of the bridge, are controlled by a preregulator control circuit for regulating the turn on time of the bridge and thus the DC output level thereof. An inverter circuit is coupled to the output of the bridge for converting the DC output therefrom to an AC signal with a frequency substantially higher than the AC supply input and with an amplitude dependent on the DC output level of the bridge. The output of the inverter circuit is coupled by a transformer to a rectifier circuit for developing a DC output dependent on the amplitude of the AC signal from the inverter circuit. A flux sensing circuit is coupled to the transformer for developing a feedback control signal dependent on the transformer flux density. The preregulator control circuit includes means responsive to this feedback control signal for controlling the turn on time of the switching rectifiers to thereby control the DC level at the bridge output and maintain a constant flux density in the transformer. In addition, the power supply includes means responsive to the load current for controlling the gain of the feedback loop to maintain a stable loop with fast response time.

High voltage resonant testing circuit

Abstract: A transformer has two secondary windings, a high voltage secondary connected across a capacitive load being tested, and a low voltage secondary connected across a variable reactor which is tuned to resonance with the capacitive load. A voltage regulator in the transformer primary winding circuit is utilized to raise the voltage across the capacitive load to the test value after resonance has been achieved. The variable reactor can be replaced by a fixed reactor and a second voltage regulator.

Hybrid power system modules

Abstract: Loadflow computer arrangements include a modularized analog network simulator which includes modular circuits representing power system generators and loads, as well as buses and lines. The modular generator circuit generator is constrained by scheduled generator electrical power and voltage magnitude values, and the modular load circuit is constrained by scheduled load power values. The modular bus, line, generator and load circuits are interconnected to simulate the power system and operate to force currents and voltages to satisfy current and voltage laws to provide the bus voltage solution.

Mechanically variable modular high reactivity power inductor for high a. c. voltage resonant testing of capacitive loads

Abstract: A mechanically variable high reactivity power inductor is described for high A.C. voltage testing capacitive loads, such as high voltage electrical power transmission cables, large capacitors, or groups of capacitors, and transmission and generation equipment.

Circuitry for converting ac power to regulated dc power

Abstract: Control circuits for gating silicon controlled rectifiers (SCR''s) to provide a direct current (DC) output which may be used to energize and control DC motors and to supply DC energy for other uses such as electric welding. Feedback regulating means are provided for maintaining a preselected current and/or voltage output at the load irrespective of changing load conditions. In the preferred form of the invention, three SCR''s and three control circuits are used to provide separately controlled, rectification of each phase of a three phase alternating current source. A selected percentage of the positive portion of each input cycle in each phase is gated to the load through the SCR''s as required to provide a predetermined current and/or voltage output. Feed-back regulation changes the firing angle of the SCR''s in each phase as required to maintain the selected current and/or voltage output. The control circuits are isolated from the load and synchronized with the source by transformer coupling. When the three phase control is employed to power a DC motor, a fourth single phase circuit is used to provide full wave rectified voltage and current to the field winding of the motor. Means are provided for simultaneously adjusting the current and voltage output of the three phase and single phase circuits as required to change the speed and torque output of the DC motor. SCR switching means are provided for reversing the polarity of the applied voltage on the field winding to reverse the direction of motor rotation.

Voltage level control for d. c.-to-d. c. converter

Abstract: A D.C.-to-D.C. converter that employs a current switch chopper with the collectors of two switching transistors feeding opposite ends of a primary of a step up transformer. The transformer has a secondary which resonantly feeds back voltage to the bases of the two switching transistors for converting the voltage from D.C. to A.C. and includes floating comparator means sensing the voltage at the collectors of these transistors to regulate the magnitude of the voltage by comparing that voltage with a reference voltage and then readjusting the current supplied to the floating emitters of the two switching transistors by a third transistor.

Network reclosing relay

Abstract: A static protective relay comprises a reclosing unit for controlling a circuit breaker which when closed couples a primary feeder or a source of supply of a three-phase power distribution system to an alternating current secondary network through a network transformer. The reclosing unit senses when a voltage corresponding to the transformer voltage minus the network voltage is within a prescribed angular displacement range with respect to the network voltage and when its magnitude with respect to the network voltage is within a prescribed magnitude range. Upon the coincidence of both conditions, a reclose signal is provided to the network protector to cause it to connect the transformer to the network.

Threshold circuit for tone-ringer

Abstract: The present invention relates to a threshold circuit for connection between the terminals of a power-supply and a load - particularly a tone-ringer for use in a station-set of a telephone or like data-transmission system. The circuit is used to switch between a dummy load and a main load - such as a tone-ringer - wherein the dummy load normally takes lesser current draw than the main load. Therefore, for a given power-supply impedance, the voltage drop across the power-supply lines will increase and in conventional circuits this reduces the voltage level below the threshold, causing parasitic oscillation. The present invention eliminates this problem by providing hysteresis in the threshold voltage by use of a positive feedback network, so that the dummy load will not be switched in again until the power-supply voltage is considerably less than the original threshold voltage level.

Dielectric system for a high voltage power transmission cable and termination

Abstract: A high voltage power transmission system includes a power transmission cable having an improved dielectric system. The dielectric system is formed of two or more concentric sections each separated by thin conductive layers and each section carrying predetermined precentages of the total applied potential. In addition there is provided an improved termination for the high voltage power transmission cable including a resistive system selected to divide the applied voltage into the preselected voltage levels.

Pulsed power supply system for neutron well logging

Abstract: A variable D. C. power supply and a variable A. C. power supply are coupled onto the upper end of a single conductor cable at the earth''s surface and from the lower end of said cable to a well logging instrument. The A. C. voltage is used to provide filament power for the ion source accelerator tube. The D. C. voltage is used to provide power to fixed D. C. loads maintained constant by regulators once a threshold is reached. The D. C. voltage is raised above the threshold to control the pulsed acceleration voltage and hence neutron output by first feeding into a unijunction relaxation oscillator in combination with an SCR output which output is transformer coupled into a voltage multiplier circuit. An antilatch feature is provided for the SCR by transformer coupling the pulses on the SCR anode back to the base of a transistor in series with the cathode of the SCR. Two outputs of the voltage multiplier circuit are connected to the cathode and anode, respectively, of an ion source accelerator tube, the cathode being connected through a resistor to retard the ripple pulsing of the cathode to allow ionization of the accelerator tube.