Abstract: In an apparatus for parallel operation of plural uninterruptable power source devices, each power source device includes at least one of an operation mode monitor for a logic operation on the output of the AC input monitoring circuit of each of the uninterruptable power source devices to feed the result thereof as a mode controlling signal to the mode controller, a parallel synchronizing signal generator for a logic operation on the output of an oscillating circuit which drives the invertor in each of the uninterruptable power source devices and, on detection of abnormality in the AC input, feeds the result thereof as a trigger pulse to the oscillating circuit, and a synchronization monitor for a logic operation on the output from the oscillating circuit in each of the uninterruptable power source devices and, when the differences between the phase of the output from the oscillating circuit of one of the triport uninterruptable power source devices and that from the oscillating circuits of remaining triport u

Abstract: A switching power source comprising a pair of output terminals, a first switch element, a reactor and a filter which are connected to each other in series between one of the terminals of an input DC power source and one of the output terminals; a second switch element connected between a connecting node for the reactor and the filter and the other terminal of the input DC power source; and means for causing energy stored in the reactor to be fed back for regeneration to the input DC power source when the switch elements are turned off, wheein the switching power source is characterized by that the first and second switch elements are alternatively actuated for ON-OFF actions at a prescribed time ratio.

Abstract: A switching power source device provides a desired AC/DC output by producing a pulse width-modulated waveform through ON-OFF control of a pair or pairs of switching elements connected in series with an input power source, eliminating high-frequency components of the pulse width-modulated waveform with a smoothing choke. The switching power source device is configured so that the input power source will not be short-circuited and consequently suffer a voltage and/or current surge, even when both switching elements in the pair assume the ON status at the same time by dividing the smoothing choke into two portions. The two portions of the smoothing choke are connected in series with the input power source when the switching elements in the pair assume the ON status at the same time.

Abstract: A ferroresonant three-phase constant AC voltage transformer comprising three transformer iron cores with one for each corresponding input supply phase, primary windings and secondary windings formed on each of the transformer iron cores, series reactance components or reactors connected in series, with the primary windings, automatic voltage regulating means for controlling secondary output voltages generated at the secondary windings to a predetermined target value, compensating windings formed so as to be inductively coupled to each of the series reactance components or reactors, and means for connecting the compensating windings in series with each other to form a closed loop circuit. The secondary output voltages are theoretically kept in balanced condition even when the loads or the primary input voltages or both are unbalanced.

Abstract: Primary and secondary windings of each transformer in a three-phase system each form a pair of independent windings, the first winding of each of the primary and secondary pairs formed on the iron core of one of the transformers and the second winding of each of the primary and secondary pairs formed on the iron core of the transformer adjacent thereto are connected in series to each other. These serially connected windings are regarded as one phase winding respectively, and they are connected to each other in either a delta connection or a Y connection. A variation in the voltage phase caused by a change in the load current of one of the system outputs has an influence not only on the phase of the voltage at that output but also on the phase of the voltages on the outputs adjacent thereto and consequently enables the deviation in the phase difference between the output phase voltages due to loss of balance of the load to be decreased to about one half.

Abstract: An AC voltage regulator includes an output voltage sensing and regulating device having a suitable filter characteristic to attenuate AC components therein occurring in the frequency ranges corresponding to the almost periodic oscillations or abnormal oscillations, or high frequency components of distorted waves which appear in the AC output voltage and are causes for such abnormal oscillations. The AC voltage regulator does not need to use a dummy load to suppress almost periodic oscillations even when the load is extremely small. The output voltage of the AC voltage regulator is free from abnormal oscillation components such as almost periodic oscillations and low frequency oscillations.

Abstract: A power source using high-frequency phase control possessing an ability to cause the transfer of electric power between a power source side and a load side to be made through a high-frequency transformer and to effect control of the output voltage by subjecting the power source side and the load side circuits to on-off control with a certain phase difference. This power source can be used as an uninterruptible power source, a device for controlled drive of a motor, a DC constant-voltage power source, or a constant-current device, for example.

Abstract: An uninterruptible polyphase AC power supply equalizes an electric power taken out from a polyphase AC power source, even if unbalanced load is connected to output.

Abstract: A constant voltage regulator involving a feedback loop by which frequency dependence may be eliminated and at the same time, hunting phenomenon in case of low load can be suppressed without inserting a dummy resistance or a reactor in its circuit, whereby high reliability may be compatible with low cost.The constant voltage regulator comprises a linear reactor and a resonance capacitor connected in series to an input power source, and a variable reactor connected in parallel with said resonance capacitor and involves a feedback loop, a saturable reactor being used as said variable reactor, and current flowing through said saturable reactor being subjected to feedback control in response to load or output voltage.

Abstract: A power conversion device of simple configuration for a solar cell which permits the solar cell to be connected to the commercial power source and enables the maximum electric power corresponding to the amount of incident sunlight to be drawn from the solar cell.A power conversion device for a solar cell of this invention comprises a voltage controlled oscillator capable of generating oscillation with a frequency which is the function of the dc output voltage of said solar cell, an inverter controlled based on the output frequency of said voltage controlled oscillator to receive the dc output current of said solar cell and convert said dc output current into an alternating current, and an inductor serving to connect the ac output from said inverter to a commercial power source.

Abstract: An uninterruptible ac power supply permits parallel operation between a commercial ac line and an inverter unit, greatly simplifies the monitoring of the commercial ac line and minimizes the transient of output voltage during the switching of mode. The uninterruptible ac power supply is comprised of an iron core divided with magnetic shunts into three sections and has an output winding, a winding for a commercial ac line and a winding for an inverter unit, one each wound on the aforementioned three sections of the iron core, the said three windings so disposed that the output winding is wound on one terminal section and the windings for the commercial ac line and the inverter unit are wound on the remaining two sections.