Showing papers on "Voltage regulation published in 1981"

Microprocessor controlled voltage regulating transformer

Abstract: A voltage regulating transformer utilizing a microprocessor and a versatile multipurpose set of hardware modules and software modules it is described. A standard tap changing mechanism is driven in response to an analog control signal to change the output voltage of the transformer in response to digitally sampled values of voltage and current which have been transformed from the time domain to the frequency domain through a software program using Fourier transform techniques. The output current is also transformed and digitally processed to determine the power factor and the direction of power flow through the transformer. By inserting the digital values of the line characteristics to the load, line drop compensation is provided for. The difference in voltage across the input and output transformers is transformed to a digital signal and internally processed to provide an indication of the position of the tap changing mechanism without relying upon mechanical devices. The various software and hardware modules are designed so as to be readily utilizable in other electrical distribution controls.

The Effects of Distribution Voltage Reduction on Power and Energy Consumption

Abstract: Voltage reduction is a practice which has long been used by electric power companies during emergencies to reduce peak demand. Since 1973, some have suggested that it can also be an effective energy conservation method. Others disagree. The purposes of this paper are to: 1) present what is known about the effects of voltage reductions on real power, reactive power, and energy, for individual and composite loads; 2) discuss the problems associated with conservation voltage reduction proposals; and 3) suggest promising approaches for further study. Tests were conducted to determine the real and reactive power dependencies on voltage of a three-phase 5 hp induction motor. The following conclusions are derived from the information presented in this paper. 1) Appliances, motors, and feeders generally show initial reductions of power consumption at reduced voltage, but little reliable information concerning energy exists. 2) Because of the lack of hard evidence and the problems associated with conservation voltage reduction programs, it would be premature for any regulatory agency to mandate such programs at the present time.

Generation Rescheduling and Load Shedding to Alleviate Line Overloads-System Studies

Abstract: A basic mathematical model to describe the problem of line overload alleviation has been developed in a companion paper. Algorithms for solving the modeland suitable for incorporation in the Newton-Raphson and decoupled load flow programs are also described. In this paper, the effectiveness of the proposed techniques is examined using a six bus model of the Saskatchewan Power Corporation system, and the IEEE 14, 30 and 57-bus test systems. A single pass of generation rescheduling and load shedding has been found to be adequate for alleviating line overloads in almost all the systems studied. Computational time of each pass of these techniques is approximately 1/2 to 3/4th of the computational time required for the initial load flow. Storage requirements are slightly more than the requirements of the load flow technique used. The proposed techniques identify and determine the existence of a physically realizable operating condition to alleviate the line overload condition. The techniques appear attractive for security and reliability studies, and for operational planning

Current rating verification system

Abstract: Method and apparatus for verifying the load rating of an active alternating current distribution circuit at a power outlet. The load rating of the distribution circuit is verified by measuring the change in line voltage at the power outlet as different loads are applied. The no-load line voltage is factored out by summing an analog signal derived from the no-load line voltage with a reference voltage to produce a null balance. When the distribution circuit is loaded by a programmed load or by the load of an external appliance such as a resistance heater, the loaded circuit waveform is transformed and rectified to produce a relatively low amplitude no-load direct current waveform. The transformed, loaded circuit waveform and the null balance waveform are summed, amplified and measured. The amplified sum corresponds exactly with the drop in line voltage across the distribution circuit at the power outlet. The value of the measured change is then compared with the specifications of the National Electrical Code to determine the electrical quality of the distribution circuit. Because this value is independent with respect to wire size, wire type or load current, the tester can be used to set an external flag indicating that the voltage drop is greater than the code limit.

Method and apparatus for automatic voltage reduction control

Abstract: Automatic voltage reduction is provided by a voltage regulator by monitoring utility load currents and comparing the load currents to a predetermined current value. When the predetermined current value is exceeded, the voltage input to the voltage regulator control is increased by a fixed predetermined amount causing the voltage regulator output to decrease. One embodiment of the automatic voltage reduction control circuit utilizes a current transformer for receiving a signal from a utility line in proportion to the amount of line load current. The current signal is compared to a predetermined current value by means of a differential amplifier to determine when the predetermined current is exceeded. The differential amplifier output then operates a relay to connect an auxiliary voltage source in series with the sensing transformer within the voltage regulator control unit.

Electrostatic spray gun apparatus

Abstract: A hand-manipulable electrostatic spray gun is disclosed which is one requiring no electric cable attached to it. Within the hand-manipulable spray gun an air turbine is driven at high speed in the order of 60,000 rpm and drives directly an alternator to generate an alternating voltage in the order of 50 volts at about 1000 Hz. The output of this alternator is supplied to a step-up transformer to achieve a secondary voltage in the order of 2500 volts. From here, it is supplied to a long chain series voltage multiplier to increase the voltage thereof to one in the order of 55-80 kilovolts. The combination of a relatively small transformer and small capacitance establishes a direct voltage output from the voltage multiplier which has an alternating voltage ripple in excess of fifteen percent. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.

Voltage Stresses Produced by Aperiodic and Oscillating System Overvoltages in Transformer Windings

Abstract: This paper investigates the internal voltages produced by various types of system overvoltages with special consideration to part winding resonance phenomena19297 which can result in very high voltage stress but may not be: adequately considered in design and test practice A case of oscillating voltage excitation is reported which caused the failure of a generator step-up transformer due to internal resonance According to theoretical considerations, internal oscillation and resonance voltages depend on the damping of the excitation voltage and of the windings For a 500 kV single phase generator step-up transformer, it is demonstrated that favorable damping characteristics of the windings can reduce to a large extent the risk of excessive internal voltages

Voltage level monitoring and indicating apparatus

Abstract: A voltage level monitoring and indicating apparatus (10) including a voltage-to-frequency converter (12), an input conditioning circuit (16) that shifts voltage signals received from different voltage sources to the same input level for the converter (12) which then produces a proportional output frequency signal, a microprocessor (40) which is software programmed to produce voltage level data in response to the output frequency signal from converter (12), and a display (42) which displays a range of numbers in response to the voltage level data. Prior apparatus are not state-of-the-art microprocessor based and require different designs when coupled to different voltage sources. The present invention is microprocessor based and has the same input conditioning circuit that can be coupled to different voltage sources for use principally to indicate voltage levels of batteries on electric fork lift trucks.

Voltage source for ion current measurement in an internal combustion engine

Abstract: A voltage source for measurement of pressure fluctuations in internal combustion engine cylinders by current detected between the electrodes of the sparkplug after the spark has died down, is derived from the ignition voltage. A capacitor can be charged to a voltage of a few hundred volts for this purpose in various ways, and either a positive or a negative measurement voltage can be provided with respect to ground across a measuring resistor for further processing. Very few additional components are required. It is possible to provide a voltage that is continuously available for the convenience of timing the measurement and for the capability of making the measurement and all of the cylinders of the engine.

Voltage current converter circuit

Abstract: A linear voltage-current converter circuit having a simplified circuit structure and operable over a wide voltage range is disclosed. The circuit comprises a first transistor having a drain connected to a power voltage through a first load element, a second and a third transistor having drains connected to the power voltage through a second load element, means for supplying gates of the first and second transistor with voltage signal, means responsive to a voltage difference at drains of the first and second transistors for controlling a gate voltage of the third transistor so as to reduce the voltage difference to zero, an output transistor, and means for supplying a gate of the output transistor with the same voltage as the gate voltage of the third transistor.

Regulated substrate bias generator for random access memory

Abstract: An improved substrate bias generator is disclosed for use in a capacitive charge storage integrated circuit memory device having an external voltage supply. The generator comprises means for generating first and second timing signals, charge pumping means disposed for pumping positive charge from the substrate of the integrated circuit memory device in response to the first and second timing signals. Removal of the positive charge from the substrate polarizes the substrate at a negative potential, which is the generated bias voltage. A voltage regulation means is disposed between the output of the charge pumping means (i.e., the substrate) and the means for generating the timing signals. The voltage regulation means provides a reference potential that regulates the amount of charge pumped from the substrate as a function of the magnitude of the generated bias voltage. The voltage regulation means includes a voltage clamp circuit that is disposed for clamping the generated bias voltage to a limited negative value; a modulator circuit means disposed at the output of the voltage regulation means; and, a generator circuit means disposed at the output of the modulator circuit means for supplying the reference potential in response to the output voltage from the clamp circuit means as modified by the modulator circuit means.

Dynamic MESFET logic with voltage level shift circuit

Abstract: GaAs digital electronics uses mainly depletion mode MESFET technology. In typical circuits, negative voltage logic input signals are required while the output voltage is positive. To connect gates, level shifters are needed to shift the positive voltage output signals such that they become suitable for the input to the next gate. A capacitor is used which performs the level shifting. As the charge leaks off the capacitor, the voltage level has to be readjusted periodically, leading to a "dynamic" circuit. A method for self-biasing of the capacitor for readjustment of the voltage level is taught.

Wide bandwidth high voltage regulator and modulator

Abstract: A combined high voltage power supply regulator and modulator which may be used with, for example, voltage tuned microwave devices The circuit is characterized by a capacitively coupled variable impedance comprising fast acting semiconductor devices which are disposed in the low voltage return leg of the power supply to facilitate biasing The variable impedance is controlled by a feedback signal to remove unwanted power supply ripple and may also be controlled by a wide variety of modulation signals to produce a modulated voltage for application to the voltage tuned microwave device

Precision setting of currents and reference voltages

Abstract: A precision voltage and current source for use, for example, in a transceiver for a carrier-sense multiple access communications network using collision detection wherein the use of one or more precise threshold voltages is required. The threshold voltage(s) is (are) created by a current source which pulls a current through a precise resistive load to yield a precise voltage. A power supply with regulated voltage drives the current source. A feedback voltage from the current source, proportional to the output current of the source, is compared with a reference zener diode voltage; the difference, or error, voltage controls the regulator to drive the regulated power supply voltage in the direction which drives the error voltage to zero. The precise resistive load is preferably formed of two resistors in series. A first threshold voltage is developed across one resistor, corresponding to the average signal level required for receiving signals on the network. A second threshold voltage is developed across the series pair of resistors, corresponding to the minimum average signal level which would be produced by a collision.

Power circuit for electronic timepiece

Abstract: A power circuit for an electronic timepiece having a liquid crystal display includes a voltage regulation circuit, a voltage reduction circuit and a voltage booster circuit. In normal operation the voltage reduction circuit operates to drive the timekeeping circuits and extend battery life. When battery voltage drops due to heavy load, such as an alarm or lamp, the voltage regulation circuit and booster circuits operate to drive the timekeeping circuits and liquid crystal display respectively. The same transistors operate in the voltage reduction and booster circuits.

Static VAR generation for transmission line compensation

Abstract: There is provided a static VAR generator having voltage regulation in combination with the capability to damp subsynchronous resonance should it occur. A novel method for controlling subsynchronous resonance is provided by monitoring the frequency of the electrical generating system and controlling the insertion of compensating inductance in response to disturbances that may result in voltage and frequency pulsations.

Supply voltage sense amplifier

Abstract: A temperature-compensated reference voltage circuit includes a transistor having a positive temperature coefficient of current. A circuit for establishing a predetermined current in the positive-temperature-coefficient-of-current transistor is connected to that transistor. A predetermined resistance serially connects the positive-temperature-coefficient-of-current transistor with a transistor having negative temperature coefficient of base-to-emitter voltage. The temperature-compensated reference voltage is established between the transistors. The temperature-compensated reference voltage circuit is particularly useful in a supply voltage sense amplifier circuit for thermal printhead drive transistors or other load elements. The sense amplifier circuit includes a circuit for comparing the reference voltage and a supply voltage. An output is adapted to be connected to a load for receiving the supply voltage. A circuit is connected to receive an input from the comparing circuit, and to said output, for enabling the output when the supply voltage is equal or greater than the reference voltage.

Effects of reduced voltage on the operation and efficiency of electric loads. Final report

Abstract: This two-volume report (Volume 2 is the Appendix) for RP1419-1 describes the efficiency of important power system loads as a function of voltage. RP1419 is divided into two phases: quantifying the energy consumption of electric load components as a function of supply voltage and providing a means for predicting energy changes as a function of voltage at the circuit level. In the first phase, a wide variety of loads have been tested at seven input voltages ranging from 100/200 to 126/252 volts (120/240-volt base). At each voltage level, equipment was required to provide identical outputs where appropriate (lighting equipment excluded). Furthermore, the effects of loading were considered. For loads without a well-quantified measure of output, such as electric ranges, appropriate measurable output quantities were developed. Subjective evaluation of performance was made if changes were obvious. To define proper test procedures and accuracy requirements, detailed test specifications were then prepared for each load component including the appropriate dependent and independent parameters to be monitored during the tests. Air conditioning equipment, heating equipment, and distribution transformers were tested by outside subcontractors because these items required highly specialized and elaborate test facilities. The complete set of test specifications and procedures is included inmore » this report.Utilizing the results gathered thus far in RP1419, a methodology has been proposed to estimate distribution system efficiency as it relates to the operating voltage level. This methodology will be developed and verified in Phase II.« less

Local Voltage Oscillation in Interleaved Transformer Windings

Abstract: In this paper, local voltage oscillation of each turn within sections of interleaved transformer winding are discussed. Because of interlacing of turns, each turn within a pair of sections of the winding has initial voltage distributions quite different from final voltage distributions. This difference brings about local oscillation when a steep impulse voltage enters the winding.

Power control circuit for induction motore

Abstract: A control circuit 3 for an induction motor 2 detects the voltage applied across the motor winding and the current flowing therethrough. The supply power and the feedback power are determined from the detected voltage and current and are supplied to a computing unit whose output controls a voltage regulator such that the voltage applied across the motor winding results in a fixed, predetermined ratio between the effective and apparent powers to maximize the motor efficiency and to minimize the motor's power consumption regardless of variations in the line voltage and fluctuations in the motor load.

Power supply for repetitive discharge apparatus

Abstract: A power supply for repetitive discharge apparatus such as a laser comprises an unregulated DC source, a primary storage capacitor, a discharge capacitor forming part of the apparatus and an energy feedback circuit between the discharge and storage capacitors operative to return to the storage capacitor energy greater than that required for a predetermined charge level on the discharge capacitor. A switch responsive to the voltage on the discharge capacitor operates a divert excess charging current into resonant charging elements in the feedback circuit for return to the primary storage capacitor. Transfer of the excess charging energy is accomplished nondissipatively to provide highly efficient cycle by cycle voltage regulation.

Monolithic voltage divider

Abstract: A voltage divider circuit is provided which can be fabricated as a portion of a monolithic integrated circuit without requiring any external capacitors. The voltage divider circuit has a pair of capacitors which are alternately switched between series connection and parallel connection to divide an input supply voltage. The voltage divider circuit can thereby provide a second supply voltage of one half the input supply voltage.

Integrating analog to digital converter having offset error compensation

Abstract: An integrating analog to digital converter having a switching circuit for selecting any one of an analog input voltage, a first reference voltage, or an analog ground voltage; an intermediate voltage selected by the switching circuit and the intermediate voltage generated by the intermediate voltage generating circuit; and a comparator for producing a signal to control the operation of the switching circuit and the voltage level produced by the intermediate voltage generating circuit according to the results of a comparison between the output signal from the integration circuit and a second reference voltage.

Temperature compensated voltage regulator for photovoltaic charging systems

Abstract: A voltage regulator (10) for use in photovaltaic (12) charging of storage batteries (14) includes a temperature compensated reference voltage (18). The circuitry of the invention permits fixed temperature coefficient and variable temperature coefficient temperature compensated regulation.

DC Power supply for an air filter

Abstract: Air filtering apparatus includes a filter cell having ionizing and collecting structure, a high voltage power supply and control unit for supplying a high voltage to the filter cell, a separate low voltage power supply unit for supplying operating power to the high voltage power supply unit and a separate probe unit for monitoring the flow of air within a duct in which the filter cell is installed. The high voltage power supply and control unit includes an output transistor in series with a primary winding of a step-up transformer and controlled by an oscillator circuit which is operative to control and limit the output voltage and current and also the current through the output transistor. The probe unit includes a pair of thermistors and a bridge circuit and operates to provide a signal which is independent of variables other than air flow velocity. A modified apparatus is also disclosed, arranged for portable use and arranged for energization from a standard power line with no separate low voltage supply.

Counter controlled pulse width modulated inverter

Abstract: A voltage source inverter has a main circuit with a switching device to which is connected a DC power source through a load, and a control circuit for controlling the on-off operation of the switching device. The control circuit includes a function generator for outputting a first signal representative of the voltage-time-integration value in correspondence with the phase of the load voltage, a time counter for outputting a second signal representative of total time of the integrated time of the period during which the DC voltage is applied to the load, and a comparator for comparing the first signal with the second signal. The output of the comparator controls the on-off operation of the switching device through a logic circuit and supplies a pulse-width-modulated AC voltage to the load.

A New AC Voltage Regulator Using Thyristors

Abstract: A new ac voltage regulator is proposed which employs thyristors as switching elements in the secondary of a power autotransformer.

Under-load switching device particularly adapted for voltage regulation and balance

Abstract: An under-load switching device particularly adapted for use with a transformer having voltage taps for voltage regulation and for balancing the phase voltages in a multi-phase AC power system includes a pair of rotary tap selectors connected in parallel to the voltage taps, and a pair of switches for alternately connecting the tap selectors to an AC line, such that load current flows through only one tap selector and an associated switch at a time. A control unit monitors the voltage on the AC line, determines the tap required to be selected to compensate for voltage variations, causes the tap selector which is not carrying load current to select the required tap, and operates the switches at a zero-current point to transfer the AC line to the selected tap.

Power supply for low-voltage load

Abstract: A power supply operating at high frequencies for energizing a low-voltage lamp and the like loads, utilizes an autotransformer in series with a switching device. The series combination receives a voltage, greater than the voltage required for load operation, from commercial power mains. The load is tapped down upon the autotransformer, with the load current magnitude being controlled by variation of the percentage of time during which the switching device is in the conductive condition, during a power supply cycle interval; the conductive time is adjusted responsive to the current sensed to be flowing through the transformer and hence through the load.

Dual voltage supply system for vehicle - produces high charging volts for battery and constant volts for lights

Abstract: The supply system has a shared control unit (10) connected in parallel with the stable loads (7,7a) to the vehicle generator (1). The stable loads are insensitive to fluctuations in their supply voltage. The control unit has a first output supply line producing a constant voltage for those unstable loads such as lamps (11) which are sensitive to fluctuations in their supply voltage. A second output supply line (12) carries twice the generator's voltage and is connected to the vehicle starter battery (5a) in order to charge it. The control unit contains a static inverter supplied from the vehicle's normal supply and with a transformer at its output. The transformer has windings for producing the constant voltage and the charging voltage for the battery. The constant voltage is controlled by a semiconductor device.