Showing papers on "Voltage regulation published in 1980"

Calculation of Energy Losses in a Distribution System

Abstract: A new method for evaluating energy and capacity losses on a distribution feeder in a rigorous manner is presented. Typical daily load shapes are integrated with a load flow procedure to produce an energy model. The performance of a feeder is analyzed by a three-phase load flow program capable of modeling the different load component characteristics as well as imbalance in loading and system configuration. The system configuration can be any combination of single, two and three-phase circuits as required, up to the capacity of the program. The effects of neutral and ground return paths are included. The load flow program utilitizes a new approach to load modeling that recognizes the key load components and their voltage sensitive characteristics.

Solid State Transformer Concept Development.

Abstract: : This report describes an effort made to determine the feasibility of developing a circuit using power semiconductor devices to duplicate the function of the power transformer A circuit concept has been developed which duplicates the primary function of voltage stepup/stepdown but does not demonstrate the DC isolation characteristic of normal transformers Several characteristics of the circuit appear very attractive, such as increased voltage regulation and relatively high efficiency (Author)

Electric motor and transformer load sensing technique

Abstract: A Faraday rotator optical sensor in combination with optical fiber transmission means is employed to monitor overload current conditions in a high voltage electrical load and transmit this information to a low voltage signal processing circuit while providing desired isolation between the high voltage load and the low voltage signal processing circuit.

Long life cardiac pacer with switching power

Abstract: A switching power delivery means for use with a relatively low voltage power source, adapted to be used in conjunction with a converter for providing a raised voltage supply to a load, wherein the load is characterized by having a first circuit portion which is voltage sensitive and draws a low current, and a second circuit portion which draws a high current and is relatively insensitive to supply deviations, comprising a switching circuit alternately connecting said respective circuit portions through respective converters to the supply so that the voltage sensitive circuit is not affected by the loading of the high current circuit.

A solid state transformer

Abstract: This paper describes a solid state step up/down transformer system which also provides AC output voltage regulation. It uses PWM AC power switching to achieve high efficiences and uses no large inductive components. Its performance has been verified by extensive computer simulation of the entire system and breadboard testing of several of the key circuits.

A Static Alternative to the Transformer On-Load Tap-Changer

Abstract: An alternative approach to the conventional on-load tap-change voltage control is described. The proposed solution involves the use of in-phase booster transformers and phase-angle controlled thyristor switching. Any specified range of continuous voltage variation can be achieved and the response is practically instantaneous. Computed and experimental results are presented, illustrating typical voltage and current waveforms as well as their harmonic content.

D-C Power supply for providing non-interruptible d-c voltage

Abstract: To maintain a continuous non-interruptible d-c operating voltage for powering a load, where the operating voltage is produced from a-c line voltage subject to failure or low voltage transients, the required operating voltage is provided by two rechargeable batteries which are alternately connected to the load. While one battery supplies the d-c power to the load, the other battery is being charged by a battery charger which is driven by the a-c line voltage. As the active battery slowly discharges and the d-c operating voltage drops to a predetermined threshold level, the battery connections are automatically switched, the charged battery being connected to the load while the discharged battery is coupled to the battery charger for recharging. The connections to and from the batteries include SCR's which receive gating pulses only when a battery switch is to occur. No continuous gating signal is needed. In the event of an a-c power outage or failure, the d-c operating voltage applied to the load will not be interrupted, nor will a momentary drop occur during the transition from one battery to the other. Moreover, by cycling each battery through its charge-discharge curve the battery's ampere-hour capacity is maintained.

Switching regulated pulse width modulated push-pull converter

Abstract: A switching regulated push pull converter which includes voltage and current feedback loops to provide a highly regulated output voltage throughout a 100 percent load range. This circuit also provides a semi-regulated auxiliary output voltage which can be loaded beyond 100 percent of its load range with no minimum load requirement on the highly regulated output voltage. A direct current drive circuit for the push-pull power switches provides a transformerless proportional drive and means are provided to compensate for transformer asymmetry.

Multiple voltage x-ray switching system

Abstract: X-ray pulses at two different photon energy levels are produced with an x-ray tube that has an adjustable resistor element in a circuit that connects the anode and filament of the tube to a high voltage supply. Two bias voltage supplies are connected in additive fashion between a control grid element of the tube and its filament to enable control of voltage drop and current through the tube. Switch means are provided to selectively shunt either or both bias voltage supplies in a repeatable order to thereby alter the bias voltage on the control grid and enable producing x-ray pulses having energies corresponding with the voltage drop and current through the tube at a selected bias voltage in accordance with the load line on the anode characteristic curve plot of the tube as determined by the value of the adjustable resistor element.

Apparatus for charging rechargeable battery

Abstract: A rechargeable battery is supplied with a charging voltage from a charging voltage source and exhibits a charging voltage characteristic having a peak shortly before the rechargeable battery reaches a fully charged state. A resistor voltage dividing circuit having a plurality of voltage output terminals is connected to both terminals of the rechargeable battery. A voltage memory device is provided for storing a predetermined voltage based on a voltage supplied from the voltage dividing circuit corresponding to the peak point of the charging voltage characteristic and comparison is made of the other output voltage obtained from the voltage dividing circuit after the peak point is passed and the stored voltage in the voltage memory device and a supply of a charging power from the charging voltage source to the rechargeable battery is interrupted when the difference between these voltages becomes zero.

Uninterruptible power supply with load regulation of standby voltage source

Abstract: An uninterruptible power supply utilizes a controlled ferroresonant regulator to derive a regulated DC voltage from a primary AC source. A reserve source of DC power is coupled to the output through a DC voltage regulator which is activated when the DC output voltage of the power supply drops below a predetermined threshold.

Simplified power factor controller for induction motor

Abstract: In the past duty cycle control for power optimization of induction motors has been accomplished with a series-inserted, phase triggered thyristor and a motor voltage-current phase angle measuring control circuit. These type of systems are undesirably complex and costly. In the instant invention power optimization is effected by utilization of a control voltage generated by the freewheeling induction motor (20) on line (16) during non-conduction periods of a series-inserted thyristor (60). The thyristor (60) firing angle is varied by the control voltage augmenting to a varying degree the charging rate of a capacitor (44) which triggers the thyristor (60). Under increased mechanical load, the freewheeling induction motor (20) control voltage decreases, the decreased control voltage accelerating the charging rate of the capacitor (44) and thus causing the thyristor (60) to conduct at a reduced firing angle so more power per cycle is delivered to the motor (20). The reverse effect occurs when the mechanical load is decreased. Therefore, the instant invention is a simpler and less costly control circuit to optimize the power factor of an induction motor.

Electronic kilowatthour meter

Abstract: An electronic meter is disclosed, for measuring functions such as power and energy of an alternating current and voltage. For measuring electrical energy, the meter includes an analog integrator for computing the integral of the voltage and of the current over a selected period of the voltage waveform. Means including a digital microprocessor and a comparison circuit are provided for generating a voltage level equal to the magnitude of the current integral or the voltage integral. In this manner, the microprocessor determines the value of the voltage or current integral. Since the integral of a sinusoidal waveform is related to its amplitude and to the power factor, the microprocessor can make a computation of energy from the values of the voltage and current integrals.

Time responsive variable voltage power supply

Abstract: A variable voltage power supply includes a switching device through which line AC current is passed in response to the time during which a level setting voltage is applied to a control circuit for the switching device. During the duration of the level setting signal, periodic electrical signals are applied to a counter which is cyclicly incremented and decremented between predetermined lower and upper count limits until the level setting signal is terminated. The count is used as a measure of time into each half cycle of the line AC voltage at which the switch device is closed, the switch device being opened in response to the zero voltage crossing at the end of each half cycle of the AC voltage.

Phase controlled voltage reducing circuit having line voltage compensation

Abstract: A voltage reducing circuit device for reducing the RMS value of an incoming AC voltage is disclosed herein. This device is especially suitable for reducing line voltage applied to a load requiring lower voltage. In a preferred embodiment, the device is one which allows a domestic made 115 VAC small heating apparatus, such as a hair dryer, to be used in foreign countries where the 230 VAC service is available. In any case, the device is one which is relatively insensitive to fluctuations in line voltage and to changes in frequency.

Reference voltage generator circuit

Abstract: A reference voltage generator circuit which can operate stably irrespective of variations in a power supply voltage and in threshold voltage of transistors employed is disclosed. The reference voltage generator circuit comprises means for dividing a power supply voltage to produce at least one internal voltage, first means responsive to an internal voltage from the dividing means for producing a first output signal having such a response characteristic that the first output signal is increased in value in response to voltage difference between the internal voltage applied thereto and the threshold voltage. second means responsive to an internal voltage from the dividing means for producing a second output signal having such a response characteristic that the second output signal is decreased in value in response to voltage difference between the internal voltage applied thereto and the threshold voltage and means averaging the first and the second output signal thereby to generate a constant value of reference voltage.

Automatic reset current cut-off for an electrostatic precipitator power supply

Abstract: An automatic electronic reset current cut-off protection circuit for electrostatic precipitator air cleaner power supplies of the type utilizing a ferroresonant transformer having a primary winding, a secondary winding for producing relatively high voltage and a tertiary winding for producing a relatively low voltage. The circuit operates to inhibit power supply operation in the event of an overload in the ionizer or collector cell by sensing a voltage derived from the high voltage and comparing the sense voltage with a fixed reference. When the sense voltage falls below a predetermined value, current through the transformer primary is inhibited for a predetermined time. Current flow is automatically reinstated and the circuit will cyclically cause the power supply to shut down until the fault has cleared. The reference voltage is derived from the tertiary winding voltage resulting in increased sensitivity of the circuit to short duration overload conditions.

Voltage regulation circuit for a solar cell charging system

Abstract: A voltage regulation circuit includes an active integrator circuit which generates an output signal representing the time integral of the error between the voltage across a load and a reference voltage. The integrator circuit output is connected to a series of voltage comparators (each having hysteresis) each of which controls one of a series of separate switch elements each controlling a proportion of the total current flow from a source to the load.

Active power supply ripple filter

Abstract: An active power supply ripple filter with low noise and low power dissipation characteristics, which tracks the voltage of the power source with low voltage drop and high current capability. The circuit consists of a control transistor connected between one terminal of a power source and one terminal of a load, a reference circuit which tracks the supply voltage, a low pass filter which filters the reference voltage and an amplifier for driving the control transistor in response to the filtered reference voltage and a feedback voltage from the load. The circuit minimizes the voltage drop across the control transistor as well as minimizing the capacitance values required for the filter capacitors.

Source voltage drop detecting circuit

Abstract: A voltage drop detection circuit provides an accurate indication of battery voltage in an apparatus subject to large fluctuations in load current regardless of the battery internal resistance. The detection circuit periodically induces an increase in load current so as to reproduce the maximum load current drawn by the apparatus, and the resulting battery terminal voltage is compared to a fixed reference. The detection circuit finds particular utility in apparatus designed to use a variety of battery types.

Apparatus for automatic regulation of AC power

Abstract: A closed loop phase control circuit. The circuit senses the temperature of a load circuit. It also senses the line voltage on each line of a multi-phase system. The sensed line voltage is full-wave rectified. Comparators for each phase compare an input signal indicative of the temperature of the load circuit with the full-wave rectified line voltage in the corresponding phase and develops an output signal when the full-wave rectified line voltage exceeds the input signal indicative of the temperature of the load circuit. Ultimately, triacs, which are in series with the load for each phase, respond to the existence of an output signal from the corresponding comparators and to a pulse from a timer and conduct in response thereto. When a triac conducts, line current is delivered to its corresponding load resistance. In this way, the time for delivery of line current (and line voltage) to the load resistance varies in accordance with the temperature of the load. Therefore, power to the load resistance is regulated in accordance with the thermal condition of the load resistance. A set point temperature at the load is thereby maintained.

Power supply and deflection circuit with raster size compensation

Abstract: A deflection generator periodically applies a trace voltage to a deflection winding to produce scanning current and periodically generates a retrace pulse voltage across the deflection winding. A supply voltage source develops the trace voltage and also provides energy to circuits, such as a high voltage circuit, coupled to windings of a flyback transformer. The high voltage circuit develops an ultor accelerating potential from the retrace pulse voltage developed across the high voltage winding of the flyback transformer. A controllable switch such as an SCR is coupled to the source and to a secondary winding of the flyback transformer. The trace voltage and energy transfer is regulated by controlling the conduction time of the SCR. The high voltage and other load circuits draw load current from the source through the flyback transformer secondary winding during retrace, resulting in high voltage retrace pulse duration and amplitude variation with variations in load current. To maintain a constant raster width, the conduction time of the SCR is varied such that the trace voltage magnitude varies in the same sense as the retrace pulse voltage amplitude variations.

Voltage control circuit responsive to FET propagation time

Abstract: An electronic timepiece contains a supply voltage source which provides a supply voltage controlled in accordance with temperature, whereby power consumption is reduced by supplying the timepiece circuit with only the amplitude of supply voltage required at any particular operating temperature. Voltage control is performed in accordance with variations in propagation times of circuit elements with temperature, as determined by variations in the frequency of a ring oscillator circuit.

Multiphase voltage monitor

Abstract: A monitor for a polyphase power line continuously compares the voltage on each phase of the power line with reference voltages that are selected percentages above and below the average of the power line voltages to detect voltage unbalance and with fixed voltages to detect high or low voltage conditions. The monitor is also responsive to phase sequence.

Steady-State Characteristics of a Current-Source Inverter/Double-Wound Synchronous Machine System for AC Power Supply

Abstract: A detailed steady-state analysis of a novel dc-to-ac conversion system used as an ac power source in dc electric railway coaches is presented. This system consists of a current-source inverter, a double-wound synchronous machine, a position sensor, and a control circuit. An equivalent circuit convenient for predicting the steady-state behavior of the system is first derived. Based on this equivalent circuit, the output voltage waveforms are then examined. It is shown that the voltage waveforms are nearly sinusoidal except that narrow spikes are superposed on them during commutation of the thyristors. As to armature reaction in the double-wound synchronous machine, it is shown that a remarkable direct reaction appears which affects the voltage regulation of the system. Finally, a method for keeping the output voltage and frequency constant is discussed.

Power generation control system for vehicle generator

Abstract: A power generation control system (2) for a vehicle generator comprises a generator (1) including an armature coil (3), an exciting coil (4) and a rectifier (5) for rectifying the AC output of the armature coil, a battery (10), and a voltage control device (6), (7) for controlling the activation of the generator in accordance with the terminal voltage of the battery. This power generation control system further comprises an abnormal voltage detector circuit (8) for detecting the voltage generated across the armature coil and cutting off the current flowing in the exciting coil when said voltage exceeds a predetermined value. The abnormal voltage detector circuit has the function to hold this forcible stoppage of power generation.

Pulse burst regulated d.c. power supply apparatus and method

Abstract: A power supply which serves as a power converter from a relatively low primary direct current energy source, to a generally higher value of secondary direct current power for application to an electric load element. The secondary power is voltage regulated. Regulation is provided by limiting the number of electric pulses of primary power produced by the converter to not more than the least total number of such pulses necessary to maintain the secondary voltage at its preferred average d.c. voltage level.

Dynamic load for testing regulated power supplies

Abstract: A dynamic load for testing regulated power supplies comprises a pass transistor or transistors which are controlled by current or voltage regulating means operates under current regulation for loading a voltage regulated power supply and under voltage regulation for loading a current regulated power supply. Only a small bias voltage is required to keep the pass transistor in conduction when the terminal voltage of the power supply under test is programmed to zero output voltage. Otherwise the power required for the dynamic load power supply comes from the power supply under test. Programming the dynamic load power supply provides a complete range of loads to the power supply under test. Additionally, feedback from the power supply under test to the dynamic load power supply can cause the latter to simulate a fixed resistor load. The dynamic load power supply replaces a wide range of the conventional power resistors used for regulated power supply testing.

Voltage level detector for battery charger control circuit

Abstract: A voltage level detector for controlling a battery charger, includes a power supply circuit adapted to be coupled to a battery during charging thereof, a first voltage regulator for providing a supply voltage for the detector, the first voltage regulator being coupled to receive power from the power supply circuit, a second voltage regulator for providing a stable source of reference voltage, the second voltage regulator being coupled to receive power from the detector supply voltage, a voltage comparator having one input thereof coupled to the stable reference voltage source, circuitry for coupling the battery to the other input of the voltage comparator, the circuit for coupling being adapted to coupled a proportion of the battery voltage which proportion equals the stable reference voltage when the battery voltage reaches a predetermined maximum level, and control circuitry responsive to the output of the voltage comparator for controlling the charging of the battery in response to the battery voltage reaching the maximum desired level

Reference voltage generating circuit in a DC power supply

Abstract: A reference voltage generating circuit in a DC power supply includes a differential amplifier for detecting a difference voltage between a reference voltage and the output voltage, and a voltage control circuit which is responsive to an output signal from the differential amplifier so as to control the DC power supply output voltage to limit the difference between the output voltage and the reference voltage to zero. More specifically, the reference voltage generating circuit includes a reference voltage source, a first variable resistor connected in parallel with the reference voltage source, a second variable resistor connected to the negative side of the reference voltage source, a third variable resistor connected to the positive side of the reference voltage source, and a switching circuit for connecting a movable contact piece of the first variable resistor to either the second or third variable resistors, or to neither of them. A predetermined voltage of a magnitude greater than, equal to or less than a rated value can be delivered as a reference voltage at the movable contact piece of the first variable resistor by selecting from a plurality of preadjusted voltage divider circuits using a single selection operation.