Showing papers on "Voltage regulator published in 1985"

Volt/Var Control on Distribution Systems with Lateral Branches Using Shunt Capacitors and Voltage Regulators Part I: The Overall Problem

Abstract: In this paper (Part I) and two companion papers (Part II and Part III) the problem of volt/var control on general radial distribution systems is formulated, simplified and solved. The objective is to minimize the peak power and energy losses while keeping the voltage within specified limits under varying load conditions. The decision variables to be optimally determined are (i) the locations, sizes and the real-time control of the specified number of ON/OFF switched and fixed capacitors and (ii) the locations and real-time control of the minimum number of voltage regulators. It is shown in this paper (Part I) that the regulator (volt) and the capacitor (var) problem may be treated as two decoupled problems. Part II of this set of three papers, conjoined with Part 1. provides the analytical tools by which optimal solutions for both problems may be determined. Application of the theory to representative radial systems is shown in Part III whhich also illustrates the economic benefits and numerical results achievable through both regulation and compensation schemes.

Volt/Var Control on Distribution Systems with Lateral Branches Using Shunt Capacitors and Voltage Regulators Part III: The Numerical Results

Abstract: In this paper, the numerical results obtained through the application of the optimal design and control schemes of the capacitor and voltage regulator problems (which are formulated and solved on an analytical basis in the previous paper, Parts I and II) are demonstrated on a thirty-bus test system with six lateral branches. The results are discussed in order to demonstrate the applicability of the theory and the bases underlying the modeling of the overall problem.

Microcomputer controlled electronic alternator for vehicles

Abstract: A microprocessor-based electronic voltage regulation system for controlling the charging of the battery in a vehicle. The conventional voltage regulator is eliminated and the intelligence of the microprocessor already present on the vehicle for controlling engine operation is used to regulate the output of the alternator. The battery temperature signal from a temperature transducer and a battery voltage signal from a sense line connected directly to the positive terminal of the battery are supplied to the microprocessor through an analog-to-digital converter. The microprocessor is programmed to ascertain from the battery temperature signal the desired set point voltage based upon an inverse first order relationship between battery temperature and desired battery voltage with preset maximum and minimum voltage set point levels. Energization of the field windings is controlled in accordance with a comparison between the desired set point voltage and the battery voltage signal on the battery sense line and is implemented in response to a control signal from the microprocessor by a solid-state power switching circuit which interfaces with the alternator field windings. In addition, the microprocessor is provided with additional feedback information relating to various driving conditions, such as vehicle deceleration, throttle position, engine RPM, and elapsed time since ignition, and is further programmed to modify the desired voltage set point or modify engine RPM in accordance with such driving conditions. Overcurrent protection for the logic circuitry and improved diagnostic capabilities are also provided.

Power supply for body implant and method of use

Abstract: An implanted blood pump system is described wherein power for driving the pump is provided by a transcutaneous transformer having an external primary winding and an implanted secondary winding. Control of the driving voltage to the pump is provided by an implanted shunt regulator. Voltage applied to the primary winding is controlled in accordance with the power factor sensed in the primary winding.

Direct current power control on selectable voltage step-up and step-down

Abstract: A DC power circuit for converting an input DC voltage into a predetermined output DC voltage includes a first switching device for switching a DC input voltage, an inductance device connected to an output terminal of the first switching device, a second switching device connected to an output terminal of the inductance device for switching an output from the inductance device, a driver circuit for comparing the output DC voltage with a first reference voltage to drive the first and second switching devices in accordance with the comparison, and a control circuit for comparing the input DC voltage with a second reference voltage to enable the driver circuit to selectively drive either the first or second switching device in accordance with the comparison. The control circuit primes or enables the second switching device to thereby step up the input DC voltage to produce a resultant output voltage from the inductance device when the input DC voltage is lower than the second reference voltage, and primes or enables the first switching device to thereby step down the input DC voltage to produce the resultant output voltage from the inductance device when the input DC voltage is higher than the second reference voltage.

Electric wheelchair with improved control circuit

Abstract: The electric wheelchair includes a battery pack (A), a right drive motor (B), a left drive motor (C), and a control circuit for controlling the amount of power supplied from the battery to the left and right control motors A speed potentiometer (24) and a direction potentiometer (26) are connected with a joystick (22) for producing a selected vehicle speed signal and a selected vehicle direction signal, respectively A right speed control circuit (E) and a left speed control circuit (F) receive the selected vehicle speed and direction signals and control the right and left motors in accordance with them Each speed control circuit includes a reference signal circuit (90) which receives the selected vehicle speed and direction signals and produces a reference signal whose magnitude varies with the speed selected for its motor The voltage and current across the armature of the motor are detected as measures of the motors actual speed A comparing circuit (92) compares the actual speed as determined by the armature voltage and current with the selected speed as denoted by their reference signal Specifically, it subtractively combines the armature voltage and the reference signal to produce a first difference signal Further, it subtractively combines the first difference signal with the armature current signal to produce a speed error reference signal The speed error reference signal controls a variable power regulator (94) which varies the amount of power supplied to the motor in a manner which tends to cause the actual and selected speeds to match

Volt/Var Control on Distribution Systems with Lateral Branches Using Shunt Capacitors and Voltage Regulators Part II: The Solution Method

Abstract: In this paper the optimal solutions of the following two decoupled problems are given on the basis of the model presented in Part I:(i) The capacitor (var) problem: determination of the locations, sizes and the real-time control of n ON/OFF switched and fixed shunt capacitors, (ii) The regulator (volt) problem: determination of the locations and real-time control of minimum number of voltage regulators. The objective in both problems is to minimize the peak power and the energy losses and to provide smooth voltage profile along the distribution system with lateral branches. For the first time, the nonlinear costs of installation of the capacitors are incorporated into the capacitor problem.

Generator voltage regulating system

Abstract: A voltage regulator for regulating the output voltage of a diode-rectified alternating current generator that supplies the electrical loads on a motor vehicle including the storage battery. The voltage regulator has an up-down counter which is incremented when the output voltage of the generator is below a desired regulated value and is decremented when the output voltage of the generator is above the desired regulating value. The magnitude of the count in the counter is repeatedly sampled and used to determine the on time of a semiconductor switch that is connected in series with the field winding to thereby control the duty cycle of the field voltage pulses. The counter is incremented at a lower rate when the speed of the engine that drives the generator is below a predetermined speed than it is when the speed of the engine is above the predetermined speed. When the generator is not rotating, the up-count of the counter is limited to a predetermined value that provides a minimum field voltage duty cycle. The system is capable of sensing either battery voltage or rectifier output voltage and is controlled to automatically switch between battery voltage and rectifier voltage under certain operating conditions.

Automatic voltage regulator means providing a dual low power responsive and output-voltage-controlling regulator signal particularly for a plural source battery powered system

Abstract: In an exemplary embodiment, a battery conditioning system monitors battery conditioning and includes a memory for storing data based thereon; for example, data may be stored representative of available battery capacity as measured during a deep discharge cycle. With a microprocessor monitoring battery operation of a portable unit, a measure of remaining battery capacity can be calculated and displayed. Where the microprocessor is permanently secured to the battery so as to receive operating power therefrom during storage and handling, the performance of a given battery in actual use can be accurately judged since the battery system can itself maintain a count of accumulated hours of use and other relevant parameters. Where an embodiment includes a main battery and a backup battery, the voltage of each may be individually measured, and each may be conditioned. Battery capacity of each may be measured. In a unique low voltage sensing circuit applicable to power sources generally, an automatic voltage regulator may itself sense a low power condition without requiring additional precision components. As an example only, such detected low power condition may be utilized to effect switch over to a backup battery or other auxiliary power supply.

A low voltage power source power inverter for an electroluminescent device

Abstract: A power inverter for an electroluminescent device is disclosed which enables the electroluminescent device to be powered from a low voltage DC power source. Switching transistors convert the low voltage DC power to low voltage AC power which is subsequently increased and coupled to a resonant circuit including the electroluminescent device. Current in the resonant circuit is sampled, referenced to half the low voltage DC power, and coupled back in phase to an amplifier and switching transistors to create an oscillator which oscillates at a frequency determined by the resonant circuit.

Power control system for a semiconductor laser

Abstract: In an optical recording system employing a semiconductor diode laser and having both read and write capabilities, the laser power must be carefully controlled at both the appropriate level for reading and at a different level for writing. Typically, a continuous read beam is emitted by the laser while pulses at the higher write power level are generated. The laser power control loop of the present disclosure maintains both the read and write output power of the laser within predetermined limits. A light sensing diode is used to determine laser output power, which is then used to operate the control circuit by adjusting the read and write current supplied to the laser. The output of the sensing diode voltage is passed through a read/write switch which is controlled by write pulses, which also control the laser. In read mode a DC signal is sent to a quad comparator circuit for read power control. In write mode a pulsed signal is sent to a sample and hold circuit which output goes through an amplifier to another quad comparator circuit for write power control.

Alternator load control system

Abstract: A load control system for controlling the field current of an alternating current generator and the idle speed control system for the engine that drives the generator. A voltage regulator senses the output voltage of the generator and controls field current by causing a semiconductor switch connected in series with the field winding to switch on and off in accordance with the magnitude of the sensed voltage. The voltage regulator is controlled to operate in a conventional manner when engine speed is higher than engine idle speed. When engine speed is in an idle speed range the duty cycle or on time of the semiconductor is controlled such that consecutive occurring on times are gradually increased to gradually increase field current when the output voltage of the generator is below a desired regulated value. The system operates to actuate an engine idle speed control system to increase the amount of fuel-air mixture supplied to the engine when the on times of the semiconductor switch are being gradually increased. In the event that engine speed decreases by a predetermined amount when the engine is operating in the idle speed range the on time or duty cycle of the semiconductor switch is reduced to a minimum to prevent engine stall.

Closed loop thermal printer for maintaining constant printing energy

Abstract: A system and method are disclosed for automatically detecting any change in average printhead resistance due to continued usage of the printhead and for automatically correcting for such resistance change in order to maintain constant printing energy. In a preferred embodiment of the invention a voltage regulator is turned off during a test mode of operation to test or measure each of the thermal elements in a thermal printhead. When the voltage regulator is turned off a constant current is sequentially allowed to flow through each of the thermal elements. The flow of constant current through an element develops a sense voltage which has an amplitude proportional to the resistance of the element being measured. The sense voltages for the elements are sequentially converted into digital signals by an analog-to-digital converter, summed together and averaged in order to develop an average printhead resistance. Each subsequent average printhead resistance after an initial average printhead resistance is compared against the initial average printhead resistance to determine whether a change in average printhead resistance has occurred. In response to a change in average printhead resistance, a processor maintains constant printing energy during a printing mode of operation by changing the pulse width of the printing pulse and/or by developing a voltage which is used to fine tune the voltage regulator to change the head voltage accordingly.

CMOS temperature insensitive voltage reference

Abstract: A temperature insensitive voltage reference is described which can advantageously be implemented using standard CMOS processing techniques. A pair of parasitic bipolar transistors are coupled with appropriate resistors to produce a voltage with a temperature coefficient that is equal in value but of opposite polarity to a zener diode voltage-temperature coefficient. This voltage is then combined with a zener diode voltage to yield the desired output reference voltage.

Power supplies with magnetic amplifier voltage regulation

Abstract: A power supply including a saturable reactor voltage regulator using a core formed of relatively inexpensive magnetically soft material with a B-H loop which is poor in squareness. The reset point of the saturable reactor core is established by a clamping circuit, including a transistor switch and diode in series, which effectively clamps a short circuit across the reactor winding when the core reaches a desired reset point on its B-H loop. The proper time of actuation of the clamping circuit is selected by a control circuit which includes a comparator for generating a control signal for actuating the switch whenever an error voltage derived from the output voltage exceeds the voltage level of a triangular wave developed by integrating a replica of the input pulsations to the magnetic amplifier structure. The saturable reactor is driven to saturation at a time during positive pulsations related to the position of the reset point. In one embodiment, the clamping circuit is connected directly across the reactor winding, while in a second embodiment, the clamping circuit is connected across a secondary reactor winding. A bias winding for the reactor may be provided to shift the B-H loop of the core to the right to increase the range of adjustment.

Volt/Var Control on Distribution Systems with Lateral Branches Using Switched Capacitors and Voltage Regulators Part III: The Numerical Results

Abstract: In this paper (Part I) and two companion papers (Part II and Part III) the problem of volt/var control on general radial distribution systems is formulated, simplified and solved. The objective is to minimize the peak power and energy losses while keeping the voltage within specified limits under varying load conditions. The decision variables to be optimally determined are (i) the locations, sizes and the real-time control of the specified number of ON/OFF switched and fixed capacitors and (ii) the locations and real-time control of the minimum number of voltage regulators. It is shown in this paper (Part I) that the regulator (volt) and the capacitor (var) problem may be treated as two decoupled problems. Part II of this set of three papers, conjoined with part I, provides the analytical tools by which optimal solutions for both problems may be determined. Application of the theory to representative radial systems is shown in Part III which also illustrates the ecomonic benefits and numerical results achievable through both regulation and compensation schemes.

Inverter type X-ray apparatus

Abstract: Disclosed is an inverter type X-ray apparatus comprising a DC-DC converter for converting a DC voltage into a different DC voltage, an inverter for inverting an output voltage of the DC-DC converter into an AC voltage, a high voltage transformer for transforming an output voltage of the inverter into a higher voltage, a rectifier for converting an AC output voltage of the transformer into a DC voltage, and an X-ray tube to which an output voltage of the rectifier is applied. In the apparatus, the DC-DC converter includes a reactor, a switching element and a capacitor which are interconnected so that the DC-DC converter can generate an output voltage higher or lower than an input voltage.

Optimal Design Strategy of Switching Converters Employing Current in jected Control

Abstract: This paper analyzes a buck/boost regulator employing current-injected control (CIC). It reveals the complex interactions between the dc loop and the current-injected loop and underlines the fundamental principle that governs the loop gain determination. Three commonly used compensation techniques are compared. The integral and lead/lag compensation are shown to be most desirable for performance optimization and stability.

Current surge limited power supply

Abstract: An inrush current limited power supply includes a regulator with a capacitor coupled across its input terminals. If voltage to be regulated is suddenly applied by a switch to the input terminals of the regulator, an undesirably large current surge occurs as the capacitor charges. The magnitude of the current surge is limited by a surge limiting resistor coupled in series with the switch. This limits the surge current, but undesirably causes power dissipation in the resistor during normal operation. The channel of a FET is connected across the resistor. The FET has a conductivity which is low when the gate-to-source voltage is low, for preventing large inrush current immediately after turn-on. A control voltage generator generates a control voltage by rectifying an alternating voltage, and it is coupled to the gate and source of the FET. In one embodiment, the control voltage generator is referenced to an input terminal of the regulator. In another embodiment it is referenced to output terminal. The alternating voltage may be generated by an oscillator, or it may be derived from operation of a switching regulator.

Power supply for providing plural dc voltages.

Abstract: A DC power supply capable of providing a number of output voltages, including a balanced positive and negative voltage supply for integrated circuit applications, includes a transformer having primary and secondary windings. A diode bridge rectifier circuit is connected across the secondary winding end terminals for providing a DC output voltage of one polarity with respect to ground. Another DC output voltage of opposite polarity is developed by AC coupling a voltage multiplier circuit between one of the secondary winding terminals and ground. DC regulator circuits are included for regulation of the DC output voltages under load conditions.

Power control for heated windshields

Abstract: The specification discloses a vehicle electrical control system capable of switching the alternator output between a uniform standard voltage and a uniform higher voltage. The control system includes a supplemental voltage regulator and a switching circuit for selectively switching the supplemental regulator into the system to regulate the conventional voltage regulator. Preferably, the control system further includes a timing circuit for powering a plurality of electrically heated windows in a timed sequence.

Engine idling load control means

Abstract: An automobile engine having a device for increasing the inkage air in idle operation when a load is applied to the engine from equipments associate with the engine. An alternator driven by the engine has a voltage regulator which controls the alternator output in response to a load condition on the alternator by controlling the field current. A control unit is provided to restrict an increase in the field current when an electric load is turned on for a time period required for having the engine output increased.

Substrate bias generator with power supply control means to sequence application of bias and power to prevent CMOS SCR latch-up

Abstract: A bias generator circuit includes a first high voltage for biasing a N-well region and a second delayed and lower voltage biasing a source region of a P-channel field-effect transistor so as to increase latch-up immunity. The generator circuit includes a high voltage generator and a multiplier circuit responsive to a power supply voltage for generating a first voltage level for biasing the N-well region. A delay network is responsive to the first voltage for generating a delay voltage. A level detection circuit is responsive to the delay voltage and the power supply voltage for generating a control signal when the delayed voltage reaches a predetermined level. A control device is responsive to the control signal for generating a second voltage for biasing the source region of the P-channel field-effect transistor. The second voltage level is delayed and lower than the first voltage level so that the PN junction is reverse biased to increase latch-up immunity.

Tap switching protection circuit

Abstract: A protection circuit is provided for a tap switching line voltage regulator of the type which selectively switches in one of a predetermined number of taps on a winding of a transformer. The selective switching of the taps is controlled in response to the sensed load voltage to provide a regulated voltage to a load in the presence of a varying input line voltage. The tap switching line voltage regulator in response to the sensed load voltage controls the conductive state of a solid state series switching element in each of the switched tap lines. The protection circuit provides current limiting inductors in series with each of the solid state switching elements with all the inductors being wound on a common magnetic core. When switching from one tap to another tap, the tap switching line volage regulator in response to the sensed voltage operates to select an adjacent tap to the tap currently selected. Thus, tap switching proceeds in a sequential fashion up and down along the taps. The series inductors are wound on the common magnetic core such that the direction of the windings alternates between adjacent taps. Accordingly, the protection circuit provides a current limiting impedance to circulating currents that is four times the impedance to normal load currents. Accordingly, the circulating current caused by leading or lagging power factor operation is limited to prevent damage to the solid state switching elements.

AC to DC converter with voltage regulation

Abstract: An arrangement for converting AC input power to DC power at a reference voltage including an output filter capacitor which is connected to the input AC line when the output voltage is less than or equal to the desired reference voltage and when the input AC voltage is less than a predetermined threshold. In this manner, charging pulses are generated twice during each half cycle of rectified AC power.

Anticipatory feedback technique for pulse width modulated power supply

Abstract: A pulse width modulated inverter system includes a comparator for comparing an output voltage with the sum of a reference voltage and a maximum allowable ripple voltage. The comparator further includes an input from the ripple current in a filter capacitor to determine when to switch between two DC voltage buses such that the maximum allowable ripple voltage will not be exceeded. The ripple voltage is constrained such that when the current is switched to maintain the ripple voltage within the set limits, the pulse width modulation frequency is maintained at a desired frequency.

Safety temperature circuit including zero crossing detector

Abstract: A temperature control apparatus has a first comparator circuit for comparing the voltage corresponding to thermal data provided by a thermal sensor with a first reference voltage generated in synchronism with the zero crossings of an AC power source. The first comparator circuit generates a pulsative output voltage which is synchronous with the zero crossings of the AC power source. This output voltage causes a second reference voltage to be applied to a second comparator circuit in the form of a pulsative voltage. The second comparator circuit compares the thermal data voltage with the second reference voltage and generates a pulse signal. This pulse signal drives a trigger circuit which triggers a thyristor connected to an electric heater.

Quiescent current reduction in low dropout voltage regulators

Abstract: An IC voltage regulator having a low dropout voltage is disclosed. A pass transistor driver is described in which the regulator quiescent current is reduced to a very small value.

High frequency high voltage power supply preventing simultaneous transistor conduction

Abstract: A push-pull current-fed parallel resonant oscillator includes a parallel resonant LC tank circuit with one end coupled to one terminal of a DC current source via a serially connected first diode and first switching transistor and the other end of the tank circuit coupled to said one terminal via a serially connected second diode and second switching transistor. Respective capacitors (17, 21) shunt the series connections. The tank circuit inductor includes the primary of a transformer whose secondary is part of the transistor drive circuit. The circuit parameters are chosen to provide a duty cycle less than 50% and a high voltage gain of the AC tank voltage. The transistors are controlled to delay the turn-off time of the on-transistor thereby allowing a negative voltage to develop on the opposite capacitor which in turn delays turn-off of its parallel connected transistor so as to provide a dead-time (Δt 2 ) during the switching interval in which both transistors are simultaneously off. The oscillator voltage gain is dependent on the circuit parameters and the load.

Apparatus for measuring characteristics of electronic devices

Abstract: An electronic device measurement apparatus measures a characteristic of an electronic device under test (DUT) by applying a sine-wave voltage to the DUT, detecting the voltage across the DUT as well as the current flowing through the DUT and displaying a characteristic curve in accordance with the detected voltage and current. The sine-wave voltage is generated in phase with an AC line voltage but the amplitude thereof is independent of the line voltage, and consequently the circuits in the measurement apparatus are not affected by variations in phase and amplitude in the line. Moreover, the generated sine-wave voltage is symmetrical, whereby display distortion is substantially eliminated. A voltage limiter and a current limiter are provided for limiting the voltage and current to be applied to the DUT to values determined by a display window, for protecting a current detecting resistor and a voltage divider connected to the DUT.