scispace - formally typeset
Search or ask a question

Showing papers on "Voltage regulation published in 1987"


Journal ArticleDOI
TL;DR: In this article, a new control technique based on dead beat control theory to obtain a nearly sinusoidal PWM inverter output voltage is described, which inherently provides very good voltage regulation, phase positioning, and compensation for load disturbances and nonlinear loads.
Abstract: A new control technique based on dead beat control theory to obtain a nearly sinusoidal PWM inverter output voltage is described. The closed-loop digital feedback system measures the output and controls the inverter switches to generate the required pulsewidth-modulated (PWM) pattern to produce low total harmonic distortion (THD) sinusoidal output voltage. This scheme inherently provides very good voltage regulation, phase positioning, and compensation for load disturbances and nonlinear loads. A theoretical analysis, computer simulation, and experimental results for a single-phase bridge inverter controlled by an Intel 8086 microprocessor-based system is presented.

313 citations


Patent
Christopher P. Henze1
13 Oct 1987
TL;DR: In this article, a digital proportional-integral (PI) controller is used to adjust the gain of a current program loop to regulate the output voltage of an A.C. to D.C power conditioner.
Abstract: An A.C. to D.C. power conditioner, which draws sinusoidal input current utilizes digital proportional-integral control to provide output voltage regulation by adjusting the gain of a current program loop. The current program loop controls the state of a power switch to force the instantaneous average current in an inductor to follow the instantaneous rectified line voltage. Variable hysteresis control provides noise immunity by increasing the ripple current in an iron-cored filter inductor when the instantaneous input voltage is high. Digital proportional-integral (PI) control provides output voltage regulation by adjusting, in discrete steps, the gain of the current program loop. A multiplying digital-to-analog converter serves as an interface between the voltage regulation loop and the current program loop. The sampling rate of the PI controller is determined by the input line frequency, which allows good transient response to be obtained. The current program loop forces the current drawn by the power conditioner to follow the input A.C. line voltage, thereby electronically emulating a resistor.

135 citations


Journal ArticleDOI
TL;DR: In this article, a new method for minimizing transmission line losses and improving voltage profile in a given system by adjusting control variables, i.e., tap position of transformers and reactive power injection of VAR sources, is presented.
Abstract: This paper presents a new method for minimizing transmission line losses and improving voltage profile in a given system by adjusting control variables, i.e., tap position of transformers and reactive power injection of VAR sources. Transmission losses are considered as a function of voltage increments. The control variables and voltage increments are related by a modified Jacobian matrix. Linear Programming (LP) is used to calculate the voltage increments which minimize the transmission losses, and the adjustments of control variables are obtained by a modified Jacobian matrix. Since this method does not need any matrix inversion, it will save computational time and memory space.

101 citations


Journal ArticleDOI
TL;DR: In this article, an approach to modeling, analysis, and design of slow distributed voltage control schemes is proposed, in particular, a dynamical voltage model governed by the under load tap-changing transformers as control tools is studied.
Abstract: In this paper, an approach to modeling, analysis, and design of slow distributed voltage control schemes is proposed. In particular, a dynamical voltage model governed by the under load tap-changing transformers as control tools is studied. Rigorous conditions are derived to predict when the LTC based scheme may be poorly coordinated and not able to maintain voltages within the limits. The proposition is that nonconvergence of LTC control scheme is one of the causes of a systemwide voltage collapse.

85 citations


Patent
17 Nov 1987
TL;DR: In this paper, a low-dropout voltage regulator with a switched redundant input, which has low dropout voltage before, during, and after a switch to the redundant input is presented.
Abstract: A low dropout voltage regulator with a switched redundant input, which has low dropout voltage before, during, and after a switch to the redundant input. In a preferred embodiment, the inventive voltage regulator includes two transistors that are controlled by the output of an error amplifier, and redundant input voltage sources. A first one of the transistors conducts when a first input voltage is greater than a second input voltage. The other transistor conducts when the second input voltage exceeds the first input voltage. When both input voltages are have substantially equal magnitude, both transistors conduct. In a preferred embodiment, one input voltage is supplied by a battery, and the other is supplied by a storage capacitor charged by the battery. When the battery fails, the storage capacitor will discharge, thus serving as a time-varying redundant voltage source in the event of battery failure.

74 citations


Patent
28 Jul 1987
TL;DR: In this paper, a switching converter in which current mode voltage regulation is implemented includes circuitry to add ramp compensation to the sensed current signal at light load and reduce or disable this ramp signal compensation at heavy load 257, 258, 259, 260.
Abstract: A switching converter in which current mode voltage regulation is implemented includes circuitry to add ramp compensation to the sensed current signal at light load and reduce or disable this ramp signal compensation at heavy load 257, 258, 259, 260. This load dependent ramp signal improves the stability of the converter and maintains its inherent current limit performace over a wide range of loading.

73 citations


Journal ArticleDOI
TL;DR: In this article, the analysis and design of a 580 kHz switching regulator incorporating a series-resonant converter is described, where on-off control is used in the feedback loop of the regulator to achieve regulation of the output voltage.
Abstract: The analysis and design of a 580 kHz switching regulator incorporating a series-resonant converter is described. On-off control is used in the feedback loop of the regulator to achieve regulation of the output voltage. An easy-to-use graphical method of analysis of transient currents is introduced as a tool for the analysis and design of the regulator. The 40W regulator circuit which has been built shows exceptionally good transient load regulation and high efficiency.

70 citations


Patent
01 May 1987
TL;DR: In this paper, the authors present a technique for continuous, simultaneous monitoring of the insulation quality of one or more pieces of high voltage ac electrical equipment, while the equipment is in service and connected to its normal high voltage source.
Abstract: The present invention teaches a technique and provides for apparatus eminently useful for the continuous, simultaneous monitoring of the insulation quality of one or more pieces of high voltage ac electrical equipment, while the equipment is in service and connected to its normal high voltage source The technique or method of the instant invention involves comparing a voltage, developed across a capacitive shunt at the capacitance tap of a transformer or bushing so equipped with a reference voltage taken from a voltage transformer or potential device connected to the same high voltage source The effecting of the instant technique requires only a minimal amount of relatively inexpensive attendant centralized control equipment and is simply and easily placed into practice by, for example, such a centralized control unit which automatically computes and displays or prints the insulation power factor and/or capacitance, either continuously or at regular intervals for each piece of said ac electrical equipment being monitored by means of the instant invention such that, for example, alarms are sounded and contacts close when the power factor for any such piece being so monitored reaches preset limits In addition, said central control unit may also make temperature corrections, compute averages, and indicate short-term and long-term trends

60 citations


Patent
29 Jul 1987
TL;DR: In this paper, a self-oscillating power converter utilizes a MOSFET power transistor switch with its output electrode coupled to a tuned network that operatively limits the voltage waveform across the power switch to periodic unipolar pulses.
Abstract: A self-oscillating power converter utilizes a MOSFET power transistor switch with its output electrode coupled to a tuned network that operatively limits the voltage waveform across the power switch to periodic unipolar pulses. The transistor switch may be operated at a high radio frequency so that its drain to gate interelectrode capacitance is sufficient to comprise the sole oscillatory sustaining feedback path of the converter. A reactive network which is inductive at the operating frequency couples the gate to source electrodes of the transistor switch and includes a variable capacitance as a means of adjusting the overall reactance, and hence the converter's switching frequency in order to provide voltage regulation. A resonant rectifier includes a tuned circuit to shape the voltage waveform across the rectifying diodes as a time inverse of the power switch waveform. The input resistance of the rectifier is controlled so that it is invariant to frequency change within the switching frequency range of the converter but inversely proportional to the load resistance.

58 citations


Journal ArticleDOI
D. M. Lauria1
TL;DR: In this article, the authors present the results of field tests conducted on the Northeast Utilities (NU) distribution system in Connecticut to measure changes in energy consumption resulting from voltage reduction.
Abstract: This paper presents the results of field tests conducted on the Northeast Utilities (NU) distribution system in Connecticut to measure changes in energy consumption resulting from voltage reduction. The economies of achieving a permanent voltage reduction by compressing existing state voltage limits to a narrower band is also examined. Although the field tests indicate that there are energy savings associated with voltage reduction, it is uneconomical to achieve voltage reduction on the NU system by compressing existing voltage limits. The use of existing line drop compensation controls is identified as a practical method of achieving voltage reduction without changing existing voltage limits.

50 citations


Patent
16 Dec 1987
TL;DR: In this article, the authors present a reverse phase-controlled dimming of an a.c.-powered load by switching power to the load on and off during each half cycle.
Abstract: Reverse phase-controlled dimming of an a.c.-powered load is accomplished by switching power to the load on and off during each half cycle. In one embodiment of the present invention, power is switched on when line voltage is substantially equal to load voltage and off at a selected time later in the half cycle or at any time that the voltage across the switch exceeds a predetermined value. Preferably, switching is accomplished with a pair of field effect transistors. The load preferably includes a capacitor from load hot to neutral. The present circuit permits quiet dimming of incandescent lamp loads without the need for complex circuitry. It is particularly well adapted for dimming low voltage lamps using a solid state transformer.

Patent
Hung-Cheng Hsieh1
17 Nov 1987
TL;DR: In this paper, a voltage level sensing circuit is proposed to hold the components of the integrated circuit in a defined state when the power supply voltage level drops below a predetermined voltage. But, the voltage level level sensing circuits can be coupled with a power-on reset circuit to generate a reset signal not only when the voltage is first supplied to the circuit, but also when the level temporarily falls below a selected value.
Abstract: A power supply voltage level sensing circuit on an integrated circuit generates a reset signal that holds the components of the integrated circuit in a defined state when the power supply voltage level drops below a predetermined voltage. The reset signal is released when the power supply voltage level returns to above the predetermined voltage. The voltage level sensing circuit is comprised of two inverters and a filter circuit. The inverters start to conduct at different power supply voltage levels and have different trigger point characteristics. The power supply voltage level sensing circuit may be coupled with a power-on reset circuit to create a voltage sensing power-on reset circuit which generates a reset signal not only when the power supply voltage is first supplied to the circuit, but also when the power supply voltage level temporarily falls below a selected value.

Patent
12 Jun 1987
TL;DR: In this paper, a biological tissue stimulator is disclosed having an adjustable high voltage power supply, which is coupled to a battery producing a high voltage signal to be supplied to an output circuit for supplying an electrical stimulation signal of a predetermined current amplitude.
Abstract: A biological tissue stimulator is disclosed having an adjustable high voltage power supply. The high voltage power supply is coupled to a battery producing a high voltage signal to be supplied to an output circuit for supplying an electrical stimulation signal of a predetermined current amplitude. An electrode is coupled to the electrical stimulation pulse and is adapted to be coupled to the biological tissue to deliver the electrical stimulation signal to the biological tissue. An adjustment mechanism is coupled to the output stage and to the adjustable high voltage power supply for comparing the amplitude of the high voltage signal to the amplitude of the voltage drop across the biological load and adjusting the amplitude of the high voltage signal dependent upon the result of that comparison. The adjustment mechanism adjusts the amplitude of the high voltage signal to minimize the difference in the amplitude between the high voltage signal and the voltage drop across the biological load thereby maximizing the energy efficiency of the biological tissue stimulator.

Patent
23 Dec 1987
TL;DR: In this paper, an inventive oscillator, inter alia, is disclosed which can be used to generate a frequency modulated control signal or a pulsewidth modulated controller signal for application to a switching means in a switching power supply.
Abstract: An inventive oscillator, inter alia, is disclosed which can be used to generate a frequency modulated control signal or a pulsewidth modulated control signal for application to a switching means in a switching power supply. The output voltage of a power supply is used to control the magnitude of a high bias voltage and a low bias voltage applied to a plus terminal of a voltage comparator, wherein when the output of the voltage comparator is high, the high bias voltage is applied to the plus terminal, and when the output of the voltage comparator is low, the low bias voltage is applied to the plus terminal. A capacitor, coupled to the output of the voltage comparator via a resistor, is coupled between the minus terminal of the voltage comparator and a ground so that when the output of the voltage comparator is high the capacitor charges. When the voltage across the capacitor exceeds that of the high bias voltage, the output of the voltage comparator goes low, discharging the capacitor until the voltage across the capacitor reaches the low bias voltage now applied to the plus terminal of the voltage comparator. The output of the voltage comparator then goes high, and the cycle repeats, thus generating a squarewave output corresponding to the output voltage of the power supply.

Patent
18 Apr 1987
TL;DR: In this paper, a control circuit for a power conversion apparatus, e.g., inverter and cycloconverter, which produces sinusoidal alternating current (AC) power through multiple switching operations of switching devices within a cycle and supplies the power to a load is described.
Abstract: A control circuit for a power conversion apparatus, e.g., inverter and cycloconverter, which produces sinusoidal alternating current (AC) power through multiple switching operations of switching devices within a cycle and supplies the power to a load. The control circuit includes a current control minor loop for controlling the instantaneous value of the output current of the power conversion apparatus in compliance with a current reference value which is determined as the sum of the load current component determined basing on the detected value of load current, and the modification current component produced by a voltage controller to current error of output line voltage of said power conversion apparatus with respect of a sinusoidal voltage reference, whereby the output voltage of the power conversion apparatus is controlled accurately to have less distortion against harmonics of the load.


Patent
23 Oct 1987
TL;DR: In this article, a DC link variable speed constant frequency power system is provided with a voltage boost circuit connected to receive voltage from a pair of DC link conductors and to supply voltage to an auxiliary supply bus.
Abstract: A DC link variable speed constant frequency power system is provided with a voltage boost circuit connected to receive voltage from a pair of DC link conductors and to supply voltage to an auxiliary supply bus. During normal system operation, the voltage boost circuit transfers the DC link voltage to the auxiliary supply bus. When a system fault occurs, such that the DC link voltage is reduced, the voltage boost circuit is activated to boost the reduced DC link voltage level and supply that boosted voltage level to the auxiliary supply bus.

Patent
24 Dec 1987
TL;DR: An EEPROM constructed in accordance with their invention includes a voltage multiplier for generating an erase voltage and a voltage regulator circuit for controlling the magnitude of the erase voltage as discussed by the authors, which includes a capacitive voltage divider for providing a first voltage proportional to the erasure voltage.
Abstract: An EEPROM constructed in accordance with our invention includes a voltage multiplier for generating an erase voltage and a voltage regulator circuit for controlling the magnitude of the erase voltage. The voltage regulator circuit includes a capacitive voltage divider for providing a first voltage proportional to the erase voltage, a reference voltage lead for providing a reference voltage and a control circuit for controlling the voltage multipler circuit so that if the first voltage is less than the reference voltage, the voltage multiplier circuit will increase the erase voltage, but if the first voltage is greater than the reference voltage, the voltage multiplier will not continue to increase the erase voltage. The voltage multiplier includes novel capacitors and transistors constructed using standard EEPROM processing to withstand high voltages without breaking down.

Patent
06 Oct 1987
TL;DR: In this paper, a voltage reduction unit for reducing the voltage supplied to a lighting element to a prescribed value and maintaining the prescribed voltage across the lighting element independently of the current flowing through it is introduced.
Abstract: A voltage reduction unit for reducing the voltage supplied to a lighting element to a prescribed value and for maintaining the prescribed voltage across the lighting element independently of the current flowing through it A lighting element is connected in series with a current switch, and the current switch is controlled by a voltage/current control unit which monitors the lighting element for changes and voltage and current characteristics The voltage/current control unit comprises a differentiator circuit for detecting a slope of an AC voltage waveform and a comparator circuit for detecting a prescribed voltage on the waveform The voltage/current control unit allows current to flow through the lighting element when both a first prescribed voltage and a prescribed voltage slope of the voltage waveform is detected, and it inhibits current flow through the lighting element when a second prescribed voltage is detected A signaling circuit receives signals from the comparator circuit and the differentiator circuit, and it communicates switching signals to the current switch for rendering the current switch conductive when signals representing the prescribed voltage and slope of the voltage waveform occur When the comparator detects the second prescribed voltage, it emits a second signal, and the signaling unit, in turn, communicates a signal for turning off the current switch

Journal ArticleDOI
TL;DR: In this article, the authors discuss the developments in control strategies for static compensators using programmable high speed digital controllers, including symmetrical firing angle control to eliminate the even harmonics in the current spectrum and hence, reduce the cost of filtering, and synchronization of the controller to the phase-locked-loop firing circuit to compensate for frequency variations.
Abstract: The purpose of this paper is to discuss the developments in control strategies for static compensators using programmable high speed digital controllers. Individual phase control of static compensators has been used in the past for balancing and power factor correction of arc furnace and single phase railway loads. With the advancements in programmable high speed controllers based on microprocessor technology, more complex computations can be accurately performed for the additional purpose of regulating and balancing the voltage feeding such loads. Other developments that will be discussed are the use of symmetrical firing angle control to eliminate the even harmonics in the current spectrum and hence, reduce the cost of filtering, and the synchronization of the controller to the phase-locked-loop firing circuit to compensate for frequency variations. The results of simulator studies will be presented.

Journal ArticleDOI
TL;DR: In this paper, a load management system that combines the existing substation solid-state recording with voltage regulation capability was tested using the substation's load tap changer, a new patent-pending power line communications technique, and a voltage-step load control receiver.
Abstract: South Carolina Electric and Gas is currently performing direct load control communications over power lines without using a power line carrier. This is the result of testing a load management system that combines the existing substation solid-state recording with voltage regulation capability. Using the solid-state recorder's extended control functions, the existing substation tap changer, a new patent-pending power line communications technique, and a patented voltage-step load control receiver, the system extends normal two-way communication between the utility operations and the substation with a one-way power line link to virtually any load. By varying the voltage level slightly, the system digitizes up to 32 different load control messages. The new voltage-step communication technique uses the substation's load tap changer to communicate one-way with the receivers over existing power lines. South Carolina Electric and Gas and the manufacturer have been performing a two-phase test of the load control system. Phase one testing showed that the percentage of successful load control message reception was 98%. Phase two testing is still in progress. Results to date show no deterioration of reception or equipment. Conclusions thus far are that the load management system is compatible with all installed utility equipment, and offers reliable direct load control.

Patent
21 Sep 1987
TL;DR: In this paper, a watthour meter with a Mark-Space oscillator and an amplitude modulator is used to calculate the energy consumption of a wye-connected load.
Abstract: A watthour meter, preferably for a wye connected load, includes a current transformer for sensing the load current, a resistive voltage divider network for sensing the line voltage, and a measuring circuit for calculating the AC electrical energy consumption of the load based on the sensed load current and line voltage. The load consumption calculations are performed using a Mark-Space oscillator and amplitude modulator in the watt transducer chip. Reduced voltage from the resistive voltage divider network is fed into the input junction of the Mark-Space oscillator. A feedback resistor is connected from the output junction to the input junction of the oscillator. The feedback resistor and the voltage divider network are mounted on the same thermally conductive substrate so that each are subject to the same thermal effects. Thus, any change, due to thermal effects, in the current through the voltage divider network seen at the input junction to the Mark-Space oscillator are compensated by a current change through the feedback line due to thermal effects on the feedback resistor. The watthour meter also includes a electronic register that receives the load consumption information from the watt transducer chip. The register is electrically isolated from the watt transducer chip and, therefore, from the voltage divider network, by an opto-isolator to reduce the possibility of electrical shock at the register. Power is provided to the watt transducer chip and the electronic register from the split secondary coils of a power transformer.

Patent
31 Aug 1987
TL;DR: In this paper, a voltage source (negative impedance) which is controlled by the output voltage and is supplied from the solar module is used instead of a regulating resistor, which consumes energy.
Abstract: This regulator increases the output power of photovoltaic modules exactly to that output voltage (battery charging voltage) which is just required even when the solar radiation is weak, and at the same time keeps the solar module very close to the characteristic point of maximum energy yield (Maximum Power Tracking, MPT). Inflating of the number of solar cells is superfluous, that is to say 20-30% of the investment costs are saved. Use of a single, very simple circuit results in: MPT plus charging regulator with overload protection and deep-discharge protection - without any reductions in efficiency, which can be 100% in the case of full solar radiation and approximately 98% in the case of weak solar radiation. The trick is to reverse the principle of the voltage-reducing in-phase regulator: a voltage source (negative impedance) which is controlled by the output voltage and is supplied from the solar module is used instead of a regulating resistor, which consumes energy. The voltage from said solar module, which is controlled automatically, is added to the module voltage. The circuit is generally suitable for any variable DC voltage source, for achieving constant (or controlled) output voltages at high efficiency and at low cost.

Journal ArticleDOI
01 Sep 1987
TL;DR: In this paper, a 3-phase self-excited induction generator coupled with a force-commutated rectifier is presented, where the rectifier was switched in such a way that its input current fundamental component was advanced with respect to the corresponding voltage, producing a capacitive characteristic.
Abstract: The paper presents a new DC energy generation system based on a 3-phase self-excited induction generator coupled to a force-commutated rectifier. This rectifier is switched in such a way that its input current fundamental component is advanced with respect to the corresponding voltage, producing a capacitive characteristic on its terminals. This characteristic helps the self-excitation and improves the direct output voltage regulation, with respect to load variation, to the range of 1 to 2%, for some firing angle. Also, this capacitive effect greatly increases the output power limit, and allows the system to supply a constant direct output voltage over a reasonably wide range of rotor speed variation. The steady-state performance of the system is analysed based on a simplified mathematical model, which is validated experimentally. A study on the influence of the smoothing reactor size is presented and it is shown that the system can operate properly even without this reactor, if there is no limit for current ripple in the load.

Patent
Hori Ryoichi1, Kiyoo Itoh1, Etoh Jun1
03 Jun 1987
TL;DR: In this article, a voltage limiter is coupled to a supply voltage providing a predetermined limited voltage, and a driver is coupled between the supply voltage and the capacitance load, and is controlled by the output pulses of the pulse generator.
Abstract: In order to drive a capacitance load at a high speed without an undesirably large increase in the circuit size, a driving arrangement is provided to charge the capacitance load in accordance with a limited voltage. A voltage limiter is coupled to a supply voltage providing a predetermined limited voltage. A pulse generator is coupled to receive the limited voltage and to provide output pulses which are, in turn, limited in accordance with the output voltage of the voltage limiter. A driver is coupled between the supply voltage and the capacitance load, and is controlled by the output pulses of the pulse generator. In this way, the capacitance load is charged through the driver in accordance with the limited voltage. Since the voltage limiter is not arranged along a series connection between the driver and the capacitance load, the internal equivalent resistance of the voltage limiter does not detrimentally influence the resistance along the series connection.

Patent
01 Jul 1987
TL;DR: In this article, the average potential of which component part (s) does not differ substantially from the high voltage is calculated for an X-ray tube high voltage supply and the total filament circuit may be approximately on the high cathode voltage and no severe requirements for insulation need to be fulfilled.
Abstract: In a circuit arrangement for producing high voltages by means of a voltage multiplier with rectifiers and capacitors and fed from an alternating current source in which circuit arrangement, a low amplitude voltage lying at the high voltage level is produced by the ripple voltage across one or more of the component parts of the voltage multiplier, the average potential of which component part (s) does not differ substantially from the high voltage. In the case of an X-ray tube high voltage supply the total filament circuit may be approximately on the high cathode voltage and no severe requirements for insulation need to be fulfilled. The ripple voltage may be used to produce other small amplitude voltages lying at a high voltage level.

Patent
27 Nov 1987
TL;DR: In this paper, a monolithic integrated circuit generates a programmable time delay under control of a digital word, which is generated by comparing a ramp signal to a threshold determined by the value of the digital word.
Abstract: A monolithic integrated circuit generates a programmable time delay under control of a digital word. The delay is generated by comparing a ramp signal to a threshold determined by the value of the digital word and appears as a time difference between a trigger pulse and a pulse generated when the value of the ramp voltage equals the value of the threshold voltage. The ramp voltage is generated by a simple resistance/capacitance charging circuit whose time constant can be adjusted by the user. The threshold voltage is set by a digital-to-analog converter (DAC) and resistor circuit which converts the digital control word into a variable voltage. In order to stabilize the device against changes in temperature and power supply variations, a voltage coupling circuit forces the threshold voltage to track changes in the ramp voltage caused by temperature and power supply variations. The coupling circuit obviates the need for precision voltage sources or current mirrors conventionally used to compensate for temperature and power supply changes. Without the need for the latter devices, the integrated circuit can be easily and inexpensively fabricated of transistors of a single bipolar type.

Patent
15 May 1987
TL;DR: In this paper, a three-phase autotransformer and a 3-phase full-wave rectifier are applied to the usual motor vehicle electrical system of the low DC voltage type.
Abstract: A high DC voltage power supply includes a three-phase autotransformer and a three-phase full-wave rectifier applied to the usual motor vehicle electrical system of the low DC voltage type. The low three-phase AC voltage of the usual system is transformed by the autotransformer to obtain a high three-phase AC voltage which is then rectified by the rectifier to provide a high DC voltage. The load energized by the high DC voltage is ungrounded to reduce the voltage available for inadvertent discharge from either load terminal to ground. Switching apparatus is provided for selectively applying the low three-phase AC voltage to the autotransformer only when it is desired to energize the load thereby avoiding at all other times the energy losses that would otherwise be associated with energization of the autotransformer. In one embodiment, the load is a windshield heater element and the autotransformer has multiple sets of input taps to provide deice and defog modes of operation, respectively. The tapping of the autotransformer on the input or primary side yields efficiencies in the construction and operation of the autotransformer. The engine driven generator of the vehicle electrical system is excited from a voltage source independent of the low three-phase AC voltage put out by the generator, at least during any period that the generator is overloaded, thereby to prevent a degenerative collapse in the generator output voltage.

Patent
Robert C. Huntington1
12 Jan 1987
TL;DR: A voltage divider comprising a plurality of series connected CMOS FETs (52, (54), (56), (58), located in P-regions, is used to establish an operating voltage as mentioned in this paper.
Abstract: A voltage translator circuit to reduce a supply voltage to a lower, predetermined, relatively constant and unconditionnally stable operating voltage without the use of external components. A voltage divider comprising a plurality of series connected CMOS FETs (52), (54), (56), (58), located in P-regions, is used to establish an operating voltage. Additional CMOS FETs (60), (62), used to supply the load current and control the no-load voltage.

Patent
10 Jun 1987
TL;DR: In this paper, the authors proposed a band-gap voltage reference having reduced output voltage noise, including the optimization of transistor area ratios as used in the bandgap device, the selection of multiple transistors in the Vbe, the section of the current range for the band gap device, resistive loads to provide minimum load noise and selective signal filtering before the output amplifier.
Abstract: A band-gap voltage reference having reduced output voltage noise. The invention embraces several novel concepts, including the optimization of transistor area ratios as used in the band-gap device, the selection of multiple transistors in the Vbe, the section of the current range for the band-gap device, resistive loads to provide minimum load noise and selective signal filtering before the output amplifier. The resulting device according to the present invention exhibits lower output voltage noise than previous band-gap voltage references, without sacrificing other important voltage reference parameters, such as line regulation, load regulation, temperature coefficient, and stability.