Abstract: A power controller for selectively coupling the voltage from a primary power source to a power output terminal or coupling the voltage from a battery backup input terminal to the power output terminal includes circuitry for receiving a reset or isolation signal. After receipt of the isolation signal when the primary power source is above a first threshold voltage, the primary power source and the backup battery source will be isolated from the output power terminal on the next occurrence of the removal of the voltage from the primary power source.

Abstract: A cooking appliance adapted for energization by a standard domestic household power supply employs a power control arrangement which accommodates electric resistive heating units designed for operation at a maximum RMS voltage level less than the RMS voltage level of the output power signal of the domestic power supply. The power control system couples power pulses from the external power supply to the heating unit at one of a plurality of available pulse repetition rates, each repetition rate establishing a corresponding RMS voltage level for application of power to the heating unit. The repetition rate associated with the maximum user selectable power setting for the appliance is effective to apply an RMS voltage level to the heating unit which corresponds to the voltage level for which the heating unit was designed. When a heating unit is turned from Off to On the power control system overdrives the unit at full supply voltage for a brief transient heat up period to rapidly heat the unit to its radiant temperature. The duration of this heat up period is controlled as a function of the elapsed time since the unit was last turned Off.

Abstract: A method is presented for finding the optimum LC combination for power factor compensation at linear loads in the presence of voltage source harmonics while the total voltamperes of the compensator capacitor and reactor is constrained. The end product is displayed in graph form where for any given compensator voltampere rating or cost, the maximum possible power factor and corresponding LC combination can be found. Examples are included showing that the cost of such an LC compensator may be less than that of a purely capacitive optimum compensator achieving the same power factor.

Abstract: A method and capacitor control apparatus for controlling the power factor and voltage on an electrical distribution line based on the power factor on the line subject to a voltage override control. Hysteresis above an undervoltage limit and below an overvoltage limit prevent undesired oscillation in switching the capacitor controls to and from the distribution line.

Abstract: A digitally synthesized source of “phantom” power for calibrating electrical power and energy meters is described. Independent sources of voltage, current, and phase angle are programmable between 0 and 240 V, 0 and 5 A, and 0 and 360 deg, respectively. The accuracy of the active and reactive power is estimated to be within ±100 ppm of the full-scale apparent power (volt-amperes).

Abstract: This paper presents the experimental results of stabilization of a model power transmission system by using a Superconducting Magnet Energy Storage (SMES). The SMES, which was composed of two sets of GTO (Gate Turn Off thyristor) power converters and a superconducting coil, is capable of controlling active power (P) and reactive power (Q) simultaneously in four quadrants by changing the firing angles of power converters. The model power transmission system was designed to simulate the behavior of a real scale long distance bulk power transmission system with voltage of 500 kV, capacity of 2000 MVA and length of 280 km. In this study, we have experimented power system stabilizing control by applying P-Q simultaneous control ability of SMES. From the results of experiment it was demonstrated that stabilizing effect by means of SMES is very significant.

Abstract: In devices for the inductive heating and keeping-warm of a workpiece by means of a plurality of inductors, a capacitor being connected in parallel with each inductor, both are fed by a power inverter, which is supplied from a common fully controllable rectifier. Each power inverter is connected via a smoothing choke in each case to the d.c. voltage output of the common rectifier and each power converter is controlled only by the assigned load oscillating circuit by voltage comparison between the actual voltage and the setpoint voltage, independently of the other power inverters and without influencing the other power inverters. The a.c. output voltage can be changed only in the case of one or a few of the power inverters by changing the respective inverter firing angle. For proportionally changing all the power inverter output voltages, this is achieved by changing the rectifier output voltage. It is expedient if the rectifier is in each case influenced in dependence on the coil with the smallest voltage.

Abstract: PURPOSE: To provide a measure against the situation where AC output voltage or reactive power output can not be increased only through control at the side of power inverter, by increasing DC voltage at the side of power rectifier. CONSTITUTION: Power fed from an AC system 1 is rectified through a transformer 2 and an external commutated rectifier 3, then inverted through a self- commutated power inverter 13 and fed through a transformer 14 to an AC system 15. Voltage and current of the AC system 15 are detected respectively through transformers 19, 20, then active and reactive powers are operated and compared with set values. Thereafter, control angle θ and phase ψ are varied by an operating unit 40 through a reactive power operating unit 21 and a constant power controller 38 so as to control the power inverter 13. When the capacity of the power inverter reaches to its limit, the phase ψ reaches a lower limit which is lower than a referential value ψ m , and thereby a limiter 52 produces an output which is added to DC voltage setting value E ref of the rectifier 3. Consequently, DC voltage of the rectifier 3 increases. COPYRIGHT: (C)1988,JPO&Japio

Abstract: A subscriber power controller (7), which regulates a voltage supply for an Integrated Services Digital Network (ISDN). The power controller and the ISDN must be protected from low input voltage and low input power. The invention provides low voltage and low power detection circuits as part of the power controller. A low voltage detection circuit (12) which generates a first detection signal is formed of a comparator with hysteresis (24, Fig. 3) and an ECL output stage (26, Fig. 3). A low power detection circuit (22) which provides a second detection signal is formed of a comparator with hysteresis (43, Fig. 4) and an output stage (44, Fig. 4). The first detection signal is used to disable the power controller and the second detection signal is used to disable high power functions of the ISDN.

Abstract: PURPOSE: To stably supply the voltage of a power system by comparing an average value of all the average values of voltages, each at each of a plurality of ground points of the system with a set voltage, and controlling the tap switching of an on-load tap changing transformer by the compared result. CONSTITUTION: The end voltages of the loads 3a, 3b in a power system are input to an input converter 12, and digitally converted voltages are input to a voltage regulating relay 13. The relay 13 calculates a time average voltage within a predetermined time for each input load terminal voltage, and then calculates an average value (whole average voltage) of all the time average voltages. The obtained whole average voltage is compared with a preset voltage, and if the whole average voltage is larger than the set voltage, a down command for executing the tap change for reducing the voltage with respect to an on-load tap changing transformer 9 is output, while if the while average voltage is lower than the set voltage, a rise command signal is output. COPYRIGHT: (C)1988,JPO&Japio

Abstract: This paper introduces a new ac Uninterruptible Power Supply (UPS) that has high efficiency, ac-input voltage regulation, and continuity of output power during any type of commercial ac-input power disturbance. These features are achieved in this UPS without the ac line-frequency energy storage components utilized in other UPSs to maintain output continuity during an ac-input power failure.

Abstract: A power feeding apparatus which is used in a high-frequency heater or the like, is further power-convert­ed by a transformer after the power provided by the power supply such as commercial power supply or the like has been converted into the high-frequency power by a transducer including a semiconductor, feeds the converted power into the load having the unidirectional electrical current characteristics of magnetron or the like. The generating voltage is dropped so that the stable power may be fed without the corona discharge and the arc discharge to be caused, the insulating withstand voltage between the wind­ings of the transformer, the pulling of the wirings, and the insulating withstand voltage may be reduced.

Abstract: An apparatus for increasing the power conversion efficiency of electronic amplifiers into both resistive and reactive loads by means of power supply driver bias level switching. The apparatus employs a multi-level direct current voltage supply to provide multi-level biasing to output power devices. Comparator circuits continuously monitor the output voltage and compare it with the direct current multi-level bias voltage of the bias power supply. In accordance with load voltage demands, a switching circuit associated with each comparator selectively connects one of the direct current multi-level power supply voltage to the power amplifying element of the amplifier whereby the minimum voltage of the available multi-level power supply voltage sufficient to maintain operation as a class B amplifier is applied across the output driver.

Abstract: A method of voltage compensation for an air/fuel ratio sensor as may be used in the exhaust system of a fuel injected internal combustion engine. The method comprises the steps of storing the design supply voltage in a look-up table, measuring the real time supply voltage and calculating a binary fraction value from the ratio of the present or real time supply voltage value and the design supply voltage value. The predetermined design threshold voltage value of the sensor is stored and then it is multiplied by the binary fraction value to get a real time threshold voltage value. The voltage output of the sensor is measured and compared with the real time threshold voltage value. In response to the comparison, a control signal is generated indicating whether or not the air/fuel mixture is lean.

Abstract: A high voltage power driven circuit for producing variable power pulses is responsive to a fixed low amplitude voltage input pulse train for determining the timing of the variable pulses, and to a variable control voltage power source for determining the power level of the pulse. In one embodiment the circuit is used in conjunction with associated circuits for transmitting an apodized and focussed beam of coherent ultrasound from an ultrasonic transducer array.

Abstract: A cathode ray tube beam deflection system operable in slew and random stroke and periodic raster display modes provides automatic power supply voltage switching (l6, l8) to maintain linear operation and high efficiency. Control of automatic switching is obtained by continuously monitoring yoke voltage, yoke current, and deflection voltage, a power supply voltage being switched to a voltage of higher magnitude to provide a higher deflection rate when the yoke voltage exceeds a predetermined level at a predetermined current polarity and returned to a power supply voltage of lower magnitude when the higher deflection rate is no longer required.

Abstract: A current-comparator technique for obtaining an instrument for accurate high voltage power measurements at very low power factors is described. The quadrature component of the load current is automatically balanced in the current comparator against a quadrature current obtained from a slave supply, thereby reducing the stringent high accuracy requirement of the instrument when used for measuring power at a very low power factors. The current-comparator-based instrument according to the present invention has an estimated accuracy with respect to its readings of better than 3 percent at 0.001 power factor, 1 percent at 0.005 power factor and 0.5 percent at 0.01 power factor and higher. It features an internal high-voltage active-divider and displays to indicate source voltage, current, power factor and reactance of the load, in addition to the power.

Abstract: In order for any failure of the power supply unit for two read-write memories which are operable in parallel, not to result in irreversible damage to data, two parallel power supply circuits are provided for the operation of the memories. Each power supply circuit is capable of supplying the operating current of one of the memories and the standby current of the remaining memory. Each of the power supply circuits in the power supply is buffered with capacitors in such a manner that, upon a fault in one of the power supply circuits, the output voltage, as soon as the capacitive buffer declines from a normal operating voltage to a threshold voltage and to a minimum operating voltage, data secure current reducing steps are taken. The capacitive circuits and threshold voltages are selected such that the period of time the voltage takes to decline from the threshold to the minimum operating voltage is longer than the time required to complete the present read-write operation and to save the relevant data into the memory. One of the memories is then put into standby mode by a monitoring device as the output voltage declines to the threshold voltage leaving only one active memory which can be operated from one of the two memory power supply circuits.

Abstract: A wall box mounted remotely operated voltage module utilizing a low voltage DC control signal which is remotely generated. A power semi conductor device is triggered to deliver a predetermined amount of power from the source of AC electrical power to a load. The AC electrical power is rectified and transformed to produce a low voltage rectified DC signal. A comparator generates a triggering signal to the power semi conductor utilizing the low voltage rectified DC signal and remotely generated low voltage DC control signal as imputs. The comparator also serves as a compensator for changes in the voltage of the AC electrical power from the source.

Abstract: This paper presents 1.8GHz low power and low voltage prescaler IC using silicon ECL technology. Its power supply voltage is 3.0v typically and power dissipation is 38mW. This performance is achieved by high optimization of circuit design technology using accurate circuit simulation.

Abstract: PURPOSE: To contrive the energy saving of electric power, by a method wherein switching operation is controlled by setting and switching the value of a voltage, outputted to a load, so that it is changed from a rated voltage to a low voltage sequentially while detecting the operating condition of the load. CONSTITUTION: An electronic computer system, employing a switching power source device, is constituted of a CPU 1, a clock oscillator 2, a logical operation circuit unit 3, a memory 4, a power source device 5, control wires 12, 13 and the like. The value of a voltage, outputted to a load, is set and switched so that it is changed from a rated voltage, for example, to a low voltage sequentially while detecting the operating condition of the load by a voltage setting and switching means. The value of the set voltage is compared with the value of the voltage, outputted to the load, and switching operation is controlled by a control means so that the value of outputted voltage becomes the value of the set voltage. According to this method, the voltage, outputted to the load, is controlled so as to become the lowest voltage which can operate the load normally whereby the energy saving of electric power may be contrived. COPYRIGHT: (C)1989,JPO&Japio

Abstract: A general approach to modeling and synthesis of harmonic-free power conversion systems is presented. The desired power conversion is achieved by controlling the transfer ratio of a time-varying network which couples the load to the source. Applying this method, harmonic-free volt-amperes reactive (var) power generation can be achieved by systems which do not include any storage elements. On the other hand this approach is suitable for simple modeling of existing efficient var compensators and power conversion circuits.

Abstract: A current-comparator technique for obtaining a wattmeter for accurate high voltage power measurements at very low power factors is described. The quadrature component of the load cturrent is automatically balanced in the current comparator against a quadrature current obtained from a slave supply, thereby reducing the stringent high accuracy requirement of the wattmeter when used for measuring power at very low power factors. The current-comparator-based wattmeter has an estimated accuracy with respect to its readings of better than 3 percent at 0.001 power Factor, 1 percent at 0.005 power factor, and 0.5 percent at 0.01 power factor and higher. It features an internal high-voltage active-divider and displays to indicate source voltage, current, power factor, and reactance of the load, in addition to the power.

Abstract: PURPOSE: To compensate a voltage variation together with a waveform distortion and a flicker by interposing, in series with an adding polarity, a compensation power source for always generating a compensating voltage in response to the variation in the voltage of a power source of a system side between the system side power source and a load. CONSTITUTION: A compensation power source 10 for always generating a compensating voltage VH in response to the variation in the voltage VS of a system side power source 1 is interposed in series with an adding polarity between the power source 1 and a load 7. The power source 10 rectifies by a rectifier 2 the power source voltage CVS to charge a capacitor 3 having a large capacity and opens/closes an inverter 4 by a signal responsive to the variation in the voltage VS output from a controller 8, thereby generating a voltage V 1 . The voltage V 1 is applied to the primary side of a coupling transformer 5, the voltage VH is generated from its secondary side, added to the voltage VS as a voltage VL, and applied to the load 7. Thus, the variation in the voltage having large varying width, and the variation in the voltage having a small varying width, such as a waveform distortion, a flicker or the like can be compensated. COPYRIGHT: (C)1989,JPO&Japio

Abstract: In this paper an attempt is made to formulate potential problems in the operation of large electric power systems under the changing strategies currently taking place. The system operates at the conditions for which it was not originally designed and the control actions are needed to compensate for this factor. If the normal operating conditions are such that large reactive power is transferred over the large distances, any unplanned event (line, generator, load outage) could lead the system to severe voltage problems. Control means for preventing this from happening are illustrated on two system examples.