Abstract: A power-factor correction system for reactive power control and concomitant power factor correction adapted to cooperate with a line supplying power at a given line voltage from a power generator to an inductive load via a given path, includes a reactive power compensating device in shunt with the line supplying power, and is adapted to be connected in shunt with the inductive load. The reactive power compensating device, in turn, includes a fixed capacitance and a voltage applying circuit delivering a voltage of continuously variable magnitude in a stepless manner to the fixed capacitance in response to any change in lagging reactive power consumed by the load, so as to correct the magnitude of the power factor in the line supplying power to the inductive load to a sensed optimum correction value, as a result of the power compensating device generating thereacross a resulting compensating reactive power in proportion to the square of the voltage of variable magnitude delivered to the fixed capacitance so as to at least partly off-set the lagging reactive power, whereby power factor correction is optimized, yet does not produce any transient. The power-factor correction system is further capable of regulating the magnitude of the compensating reactive power to achieve optimization for line voltages having waveforms deformed from a sinusoid of the fundamental frequency and for non-linear loads. The system is also arranged to prevent destructive series resonance between a transmission line and the fixed capacitance.

Abstract: In an electrostatic precipitator system powered by a primary power source, the power supply has a converter and a high voltage device. The converter can be coupled to the primary power source for producing a converter voltage with a different frequency content. The high voltage device is driven by the converter, producing from its converted voltage a high voltage. This high voltage is influenced by the different frequency content, having at least one frequency component at a predetermined low frequency which is sized to promote efficient precipitation.

Abstract: A system for calibrating active/reactive power and energy meters under sinusoidal conditions using a current comparator bridge is described. Measurement can be made at any power factor from zero lag through unity to zero lead, positive or negative power, at 100 to 120 V, 1 to 5 A, and 50 or 60 Hz. The system features a digital oscillator, a thermal rms ac/dc voltage comparator, an automatically compensated capacitor for producing an accurate and stable reactive component, and a microcomputer for control and data reduction. The systematic uncertainty of the calibration system is estimated to be not more than 15 parts per million (ppm).

Abstract: Low power for a radio transmitter is indicated by an output power detector voltage falling below a low power reference voltage derived from an existing power control circuit.

Abstract: PURPOSE:To prevent overload applied to a fuel cell by detecting d.c. side voltage of a converter which converts D.C. power of a fuel cell to A.C. power, and suppressing increase of active power of the converter when the D.C. voltage dropped below setting voltage. CONSTITUTION:The D.C. output power of a fuel cell 5 is converted to A.C. power with a D/A converter 10, and supplied to a power line. Active power Pa and reactive power Qa are compared with setting values Ps and Qs and the converter 10 is controlled through a controller 14. Output voltage Va of the fuel cell 5 is detected with a detector 18 and compared with setting voltage Vs with a comparator 19. When output voltage dropped below setting voltage, a signal is inputted into an active power comparator 11 through a lower limit controller 21 and output to power line is controlled. Overload applied to the fuel cell 5 which is caused by quicker electricity output response than control response of fuel or air of the fuel cell is effectively prevented.

Abstract: As power levels of spacecraft rise to the 50 to 100 kW range, it becomes apparent that low voltage (28 V) dc power distribution and management systems will not operate efficiently at these higher power levels The concept of transforming a solar array voltage at 150 V dc into a 1000 V ac distribution system operating at 20 kHz is examined The transformation is accomplished with series-resonant inverter by using a rotary transformer to isolate the solar array from the spacecraft The power can then be distributed in any desired method such as three phase delta to delta The distribution voltage can be easily transformed to any desired load voltage and operating frequency The reasons for the voltage limitations on the solar array due to plasma interactions and the many advantages of a high voltage, high frequency at distribution system are discussed

Abstract: Two different set voltages are respectively compared with a power source voltage. When the smaller set voltage which is close to a minimum operating voltage of an arithmetic circuit coincides with the power source voltage, a clock signal generator, and hence the arithmetic circuit are stopped. When the power source voltage increases to coincide with the larger set voltage after the clock signal generator is stopped, the clock signal generator and hence the arithmetic circuit are restarted.

Abstract: This paper describes a device suitable to control the output of several converters, each voltage regulated and parallel operating with forced load sharing, so that, when failure occurs, it becomes possible to identify and shut-down the failed unit without affecting to other parallel connected units. Undervoltage and overvoltage supervision is garanted by the device to avoid output voltage changes dangerous for the supplied equipment. The supervision device has been designed by taking in to account the use of last power transistor on the power circuit. Beacause of that, the device includes a pulse by pulse control of power transistor integrity to cut-off as possible the failed unit. Besides, the device is able to control the transistor peak collector current to shut-down the power transistor, with an automatic reset function, during output short-circuits or overloads. The device described has been utilized in the transistorized buck/boost converters and rectifiers for low power system for telecommunication plants [3].

Abstract: @ Apparatus for detecting, in advance, by a desired length of time, the imminent failure of electric output power provided by an electric power supply due to the reduction or loss of input power. The magnitude of the voltage on an energy storage reservoir capacitor is monitored for deriving a voltage signal proportional to the rate of change thereof. The rate of change voltage (Vc) is multiplied (35) by a voltage (VWT) proportional to a desired early warning time interval and this product is added to a voltage (Vm) proportional to a minimum vlaue of voltage on the capacitor, thus representing an amount of stored energy sufficient to sustain normal output power for a desired time interval. The voltage derived by the adding means is compared (38) with the voltage on the energy storage capacitor for signalling imminent power supply failure when the compared voltages are equal.

Abstract: PURPOSE: To perform an impulse voltage testing between phases and poles avoiding the application of excessive voltage to a ground insulation part by using an impulse voltage generator with a voltage dividing means. CONSTITUTION: A metal body 4a of a sample appliance 4 used always grounded is insulated from the ground through an insulation device 10. The metal body 4a is connected to an intermediate potential tap (m) of a voltage dividing means 11 provided in parallel on an impulse voltage generator 1. Then, one of conductors intended for application of a voltage is connected to a high voltage terminal of the generator 1 and the other grounded. As a result, a specified impulse voltage is applied between the phases or poles of the appliance 4. At this point, a voltage reduced by a voltage supported by the insulation device 10 is applied to the ground insulation part of the appliance 4. Thus, by adjusting the position of the intermediate potential tap (m), an impulse voltage testing can be done between the phases and poles avoiding the application of excessive voltage to the ground insulation part. COPYRIGHT: (C)1985,JPO&Japio

Abstract: An analysis is presented of voltage transients resulting from a short circuiting accident in a telecommunications DC power distribution system. Two typical sorts of DC distribution systems, bus-cable and radial-cable methods, are modeled and numerically analyzed. Main results are as follows: (1) DC distribution system models, which can simulate voltage transients waveforms accurately, are obtained. (2) A radial-cable method is desirable for limiting voltage transients. (3) Installing capacitors at a distribution board is effective to limit voltage transients.

Abstract: A further improvement of the method of generating three-phase stepped voltage waveforms is described. The proposed system consists of a three-phase inverter that is transformerless, a triple-frequency single-phase inverter with a transformer, and three power semiconductor switches that link the two inverters. The voltage waveform obtained has a total harmonic distortion of 7·99%, and the predominant harmonics are the 17th and 19th. This method makes possible a reduction in the size and weight of equipment for producing an uninterrupted power supply with reduced harmonic distortion. The theoretical results are verified by an experimental Bet up using power transistors with a rating of 450 V and 30 A.

Abstract: The paper presents the comparative study of some methods of power factor control and harmonic reduction of single phase converters. The comparison is done on the basis of power factor, dominant harmonics in source current, distortion factor, RMS line current, reactive power, second harmonic in load voltage and load voltage ripple factor. The data presented can be usefully employed in selecting a suitable scheme for a particular application.

Abstract: The potential of a new adaptive control for reactive power sources is investigated. In the large disturbance regimes, the adaptive signals supplement the nominal, thyristor activated, reactors and capacitors in manipulating the network voltage. Convergence of the scheme, and its relationship to the inherent system nonlinearities is considered.

Abstract: Solar generators, fuel cells and similar DC voltage sources have a current / voltage characteristic, is on a point ( "Maximum Power Point" MPP) distinguished by the fact that there can be taken from the DC voltage source, the maximum power. In an arrangement in which the DC power source 1 via a controllable power transformer, for. B. a interposing CTs 2 feeds a load 3, the optimum operating point is set automatically in that the transducer, a desired value U Takes as a result of the barge, the power output of the DC voltage source, the reference value U Is the sign of the power change is negative, then the target value is opposite to the sign of the additional setpoint changed. Characterized that the current operating point is in each case corrected to the optimum operating point according to a finite number of setpoint changes is achieved. Since the sign of the power change is detected by evaluating the time derivative of the Leistungsistwertes (differentiator 17) Storgrosenamplitude AU can be made very small ', so that the operation of the consumer is not impaired.

Abstract: PURPOSE:To obtain a controller capable of stably operating even in a low speed range by detecting the power factor of the output of an inverter and correcting the set voltage value by a detection signal. CONSTITUTION:The power factor of the output of an inverter 5 is detected by a power factor sensor 15, the output of a voltage pattern generator 9 and hence the set voltage value is corrected by a correcting circuit 16, and the peak value of the sinusoidal wave is controlled so that the output voltage of the inverter 5 becomes substantially set value. Since the output voltage of the inverter tends to increase as the power factor is deteriorated, the output of the generator 9 and hence the voltage set value decreases by the correcting circuit 16, thereby controlling the output voltage of the inverter substantially constantly irrespective of the power factor.

Abstract: A new integrated high voltage power PNP (I C ? 600mA) has allowed to implement a very low drop (0.6V) voltage regulator withstanding ± 80V transients. A trimmed (± 2%) reference makes possible a precise "power on/off reset".