Abstract: A power supply system is operable to harvest power at low and high line currents. A current transformer is arranged to couple to a power transmission line. A current sensor which may be a Rogowski coil is arranged to couple to the power transmission line. Branches of power supply circuitry are connected to a plurality of secondary windings of the current transformer. A control circuit selects one of the branches of power supply circuitry, depending on sensed magnitude of line current, to provide electrical power to an output capacitor. Sufficient stored energy is also provided for performing a backup of operating parameters when the line current reduces to zero.

Abstract: The present disclosure provides a circuit for balancing voltages of battery packs to be connected in parallel, comprising: IN-side switches and OUT-side switches; a DC-DC converter with an IN terminal connected to the IN-side switches and an OUT terminal connected to the OUT-side switches; and a controller to operate an IN-side switch to connect a Vmax battery pack to the IN terminal, operate an OUT-side switch to connect a Vmin battery pack to the OUT terminal, and activate the DC-DC converter to transfer energy from the Vmin battery pack to the Vmin battery pack. The controller responds to an IN terminal voltage being sufficiently close to a voltage of a first battery pack by operating an IN-side switch to connect the first pack to the IN terminal, and responds to an OUT terminal voltage being sufficiently close to a voltage of a second battery pack by operating an OUT-side switch to connect the second battery pack to the OUT terminal.

Abstract: A resonant core power supply includes a core with excitation, resonant, and load windings where the resonant winding is coupled to a tank circuit and a controller manipulates the phase, amplitude and waveform of an excitation signal applied to the excitation winding.

Abstract: A ferroresonant transformer system has a core, a shunt, first and second input windings, an inverter winding, a tank winding, a resonant capacitor, an output capacitor, and a plurality of switches. The tank winding defines a plurality of switch tap locations and at least two output tap locations. The resonant capacitor is connected across at least a portion of the tank winding. Each switch is operatively connectable between one of the switch tap locations and the resonant capacitor. Each output terminal is operatively connected to one of the at least two output tap locations.

Abstract: A magnetic core is provided. The magnetic core includes a plurality of magnetic core units each having at least one non-shared magnetic core part that is not shared with the neighboring magnetic core unit, wherein a reluctance of the shared magnetic core part is smaller than the reluctance of a non-shared magnetic core part of the magnetic core units, and directions of a direct current magnetic flux in the shared magnetic core part of the neighboring two magnetic core units are opposite.

Abstract: An integrated inductor apparatus integrated to be a plurality of inductors is provided. The integrated inductor apparatus includes inductor windings to form inductors and includes at least two windows each having at least one of the inductor windings disposed therein and magnetic core units, each having a closed geometrical structure to form one of the at least two windows, wherein two of the neighboring magnetic core units have a shared magnetic core part. The magnetic core units comprise at least two kinds of material having different magnetic permeability corresponding to different sections of the magnetic core units, wherein the reluctance of the shared magnetic core part is smaller than the reluctance of a non-shared magnetic core part of the magnetic core units.

Abstract: A converter circuit, comprising: a supply node and an output node of the converter circuit, a half-bridge arrangement coupled to the supply node and including a pair of electronic switches alternatively switchable between conductive and non-conductive states with a drive node therebetween, a transformer with a primary winding driven by the drive node and a secondary winding including two portions with a center tap node coupled to the output node of the converter circuit and an inductive component. The inductive component including two magnetically coupled winding halves with a respective center tap node, the inductive component being coupled to the ends of the secondary winding of the transformer with the respective center tap node coupled to the output node of the converter circuit.

Abstract: A ferroresonant transformer system has a core, a shunt, first and second input windings, an inverter winding, a tank winding, a resonant capacitor, an output capacitor, and a plurality of switches. The tank winding defines a plurality of switch tap locations and at least two output tap locations. The resonant capacitor is connected across at least a portion of the tank winding. Each switch is operatively connectable between one of the switch tap locations and the resonant capacitor. Each output terminal is operatively connected to one of the at least two output tap locations.

Abstract: A method for manufacturing a heavy-current transformer with at least one primary winding and at least one secondary winding with surfaces for contacting connects first inner surfaces of the at least one secondary winding with an I-beam of electrically conductive material of the heavy-current transformer with a first soldering material at a first, higher melting temperature, and subsequently at least one contact plate of electrically conductive material is soldered with exterior surfaces of the at least one secondary winding with a second soldering material at a second melting temperature that is lower as compared to the first melting temperature.

Abstract: A lighting device includes a ferroresonant transformer that receives an alternating current (AC) power signal and outputs an output power signal. The lighting device further includes a rectifier coupled to the ferroresonant transformer. The rectifier rectifies the output power signal from the ferroresonant transformer and generates a rectified power signal. The lighting device also includes a dc-to-dc converter coupled to the rectifier, wherein the dc-to-dc converter receives the rectified power signal and generates a regulated power signal.

Abstract: A self-powered power sensor (SPPS) measures electrical parameter measurements at points of interest, such as circuit breakers, machines, and the like. The SPPS which comprises of components that may require corrections, such as the errors induced by, but not limited to, the use of a split core mounted around a current carrier, and hence calibration coefficients are provided based on test, measurements and/or calculations respective of the devices. These coefficients may be stored in a database for retrieval when calibration of measurements received from a measuring device. In one embodiment at least one of the calibration coefficients is stored on SPPS.

Abstract: A LED retrofit lamp for replacement of fluorescent lamp or tube driven by fluorescent ballast is provided. The retrofit lamp is compatible with the fluorescent ballast that requires the presence of a barrier for striking an arc voltage. The present invention provides a strike barrier—a controllable barrier that does not allow current conduction until a threshold voltage is reached. When a current above the threshold voltage passes through the strike barrier, the circuit latches and allows conduction at normal voltage. The present invention also provides a circuit that replicates the cathode heater resistance of a fluorescent lamp to rapid start and programmed start ballast.

Abstract: A method and an apparatus for a shunt measurement are provided. In one embodiment a measurement unit includes an input for a source device, the source device configured to provide a first analog voltage level to be measured in a first operating mode of the source device and a second analog voltage level to be measured in a second operating mode of the source device, a control input configured to detect the operating mode of the source device and an input stage configured to minimize a reaction time of the measurement unit after a change of the operating mode of the source device.

Abstract: In some embodiments, an exemplary inventive device of the instant invention is a reactor which includes at least the following: a core, including: at least one leg, including: a first lamination, where the first lamination is made from a high permeability material, where the high permeability material has a magnetic permeability that is at least 1000 times greater than the permeability of air; a second lamination, where second lamination is made from the high permeability material; a bracket, where the bracket is configured to secure the first lamination and the second lamination in a spatial arrangement to have a space between each other; and a plurality of blocks made from a low permeability material, where the low permeability material has the magnetic permeability that is less than 100 times the permeability of air.

Abstract: Method and apparatus for power conversion. In one embodiment, the method comprises operating a resonant converter in a ring mode comprising (i) holding a plurality of switches of the resonant converter in a first switching state throughout a pre-determined number of resonant periods; and (ii) maintaining the plurality of switches in the first switching state for a fraction of a subsequent resonant period until an amount of energy has been transferred through the resonant converter to achieve a pre-determined output power from the resonant converter.

Abstract: An analog open-loop self-oscillating boost converter is provided including: an output terminal for supplying an output voltage bus; an input terminal for receiving variable input power; a varactor positioned in series with the input terminal; and an oscillating network having an inductor, a resistor and a capacitor in a parallel orientation, the oscillating network connected to a semiconductor device and the varactor.

Abstract: An electrical system includes a transformer structured to be selectively coupled to an AC source that provides a main AC voltage, the transformer having a number of sets of primary windings and a number of sets of secondary windings, and a charging module structured to generate a magnetizing AC voltage. The charging module is structured to selectively provide the magnetizing AC voltage to: (i) one of the number of sets primary windings, or (ii) one of the number of sets secondary windings. The magnetizing AC voltage is such that responsive to the magnetizing AC voltage being provided to one of the number of sets of primary windings or one of the number of sets of secondary windings, one or more of the number of sets of primary windings will be magnetized in a manner wherein a flux of the one or more of the number of primary windings is in phase with the main AC voltage provided from the AC source.

Abstract: An isolated boost power converter comprises a magnetically permeable multi-legged core (102) comprising first and second outer legs (132; 136) and a center leg (134) having an air gap (138) arranged therein. A boost inductor (Lboost) is wound around the center leg (134) or the first and second outer legs (132; 136) of the magnetically permeable multi-legged core (102). The boost inductor (Lboost) is electrically coupled between an input terminal (104) of the boost converter and a transistor driver (106) to be alternatingly charged and discharged with magnetic energy. A first and second series connected secondary transformer windings (SW1; SW2) with a center-tap (116) arranged in-between are wound around the first and second outer legs (132; 136), respectively, of the magnetically permeable multi-legged core (102).

Abstract: A battery system utilizes a plurality of transformers interconnected with the battery cells. The transformers each have at least one transformer core operable for magnetization in at least a first magnetic state with a magnetic flux in a first direction and a second magnetic state with a magnetic flux in a second direction. The transformer cores retain the first magnetic state and the second magnetic state without current flow through said plurality of transformers. Circuitry is utilized for switching a selected transformer core between the first and second magnetic states to sense voltage and/or balance particular cells or particular banks of cells.

Abstract: A medium voltage adjustable frequency drive includes an input isolation transformer having a three-phase input and a three-phase output, a converter having a three-phase input electrically connected to the three-phase output of the input isolation transformer and an output providing a direct current bus, an inverter having an input electrically connected to the output of the converter and a three-phase output, and a pre-charge circuit. The pre-charge circuit includes a ferro-resonant transformer circuit having a primary winding structured to input a low voltage and a secondary winding structured to output a medium voltage and provide a constant current source. The pre-charge circuit also includes a medium voltage diode bridge having an input receiving the medium voltage from the secondary winding of the ferro-resonant transformer circuit and an output structured to provide the constant current source to the direct current bus.

Abstract: For the purpose of providing a resonant switching power supply device having a wide output voltage variable range by changing its switching frequency, the resonance circuit thereof comprises a switching transformer, a first resonance section connected in series with the switching transformer, and a second resonance section connected in parallel with the switching transformer, wherein the resonance frequency characteristic in the case that the DC load current is large is formed using the series-connected devices of the first resonance section, and the resonance frequency characteristic in the case that the DC load current is small is formed using the first resonance section, the second resonance capacitor of the second resonance section and the switching transformer.

Abstract: A filter uses a special autotransformer that has a ferromagnetic core with a plurality of legs and flux return bars. A first coil is located on one leg, and a second coil is located on the same leg, but spaced from the first coil. The first coil and at least part of the second coil are connected in series to receive distorted alternating current and at least that part of the second coil is connected to an output terminal. Between the coils and extending at least part of the way from the first leg to an adjacent leg is a magnetic shunt assembly to divert part of the flux generated in the first coil by the alternating current so that that part does not link with the second coil. An air gap is located to link with the second coil to create an inductor in that coil by flux in the second coil, and a capacitor is connected across the second coil to tune it to the fundamental frequency of the alternating current and substantially reduce harmonics in that current.

Abstract: A method of designing a high power factor integrated ferroresonant constant current source includes the steps of providing an input coil disposed about a ferromagnetic core and to be coupled to an AC voltage source. An output coil is to be coupled to a load. A control coil is coupled to a switch for regulating current output of the constant current source. A first capacitor coil is inductively coupled to the output coil and coupled to a capacitor to provide a first resonant sub-circuit having maximum gain, and a second capacitor coil is inductively coupled to the control coil and coupled to a capacitor to provide a second resonant sub-circuit to control resonant gain. A flux density (BPRI) is selected for a portion of the core around the input coils that is substantially lower than the flux density BCAP of a portion of the core around the capacitor coils.

Abstract: A controlled ferroresonant constant current source includes a ferromagnetic core accommodating the below-mentioned inductors. An input coil is to be connected to an alternating voltage source. An output coil is inductively coupled to the input coil, and is to be connected to a load. A control coil is inductively coupled to the output coil, and is to be connected to a switch for regulating the current output of the constant current source. A first capacitor coil is inductively coupled to the output coil, and is to be connected to a capacitor to provide a first resonant sub-circuit having maximum gain. A second capacitor coil is inductively coupled to the control inductor, and is to be connected to the capacitor to provide a second resonant sub-circuit to control resonant gain.

Abstract: A distribution series capacitor control system is provided with a sub-harmonic detection module connected to an input signal and operable to detect the presence of at least two distinct types of sub-harmonic content in the input signal. A logical signal processor is electrically connected to the sub-harmonic detection module, and operates to independently determine the existence of self-excitation during induction motor starting and ferroresonant phenomena based upon the at least two distinct types of sub-harmonic content, respectively. A system controller is electrically connected to the logical signal processor and operates to eliminate effects of self-excitation during induction motor starting and ferroresonant phenomena on the system.

Abstract: A ferroresonant transformer includes a three-legged magnetic core. The core includes a center leg, and first and second flanking legs. Each of the center and flanking legs have respective first and second longitudinal ends. The first flanking leg is positioned at an opposite side of the center leg relative to the second flanking leg. A first end-connecting portion magnetically couples the first ends of the center and flanking legs, and a second end-connecting portion magnetically couples the second ends of the center and flanking legs. The center leg defines a substantially non-magnetic space, such as an air gap, along a magnetic flux path extending along the center leg from the first end-connecting portion to the second end-connecting portion in order to reduce the total harmonic distortion of the ferroresonant transformer.

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: A power supply is disclosed which comprises a ferroresonant circuit, the ferroresonant circuit including a transformer with a core of magnetic material, a primary winding, a secondary winding, and reactive means coupled with at least one of the windings. The transformer also has at least one bias winding. An alternating voltage is applied to the ferroresonant circuit, the alternating voltage having a frequency that is approximately equal to a resonant frequency of the ferroresonant circuit. An output circuit is coupled to the secondary winding. A signal from the output circuit is applied as a feedback signal to the bias winding to control DC flux bias of the core. In an illustrated embodiment, the means for applying an alternating voltage signal to the ferroresonant circuit includes an oscillator for generating alternating voltage control signals, and a switching circuit responsive to an input power source for generating the alternating voltage signals under control of the oscillator.

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 resonant power converter is disclosed which is constructed on an integrated magnetic core, with primary, secondary and tertiary windings occupying separate legs of the core. The tertiary winding is connected in a resonant circuit and induces a flux in the primary leg that causes the primary winding current to assume the shape of a series of generally sinusoidal pulses. Primary winding switching can thus occur at zero primary current between pulses, thereby eliminating prior interference problems. Furthermore, the converter can be operated in a pulse width modulated mode to accommodate for varying output load levels without the problems of low frequency operation encountered by prior frequency modulated resonant converters.

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 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.

Abstract: An AC line voltage regulator having a voltage sensing circuit for sensing and producing signals representative of the difference between a predetermined voltage level and the line voltage level and a load current sensing circuit for sensing and producing a signal representative of the magnitude of a load current drawn from the regulator. An actuation circuit combines the signals produced by the voltage and current sensing circuits to control the timing of a selectively switchable dispensing circuit which dispenses energy into an oscillatory circuit oscillating at the line voltage frequency and connected between input and output ports of the regulator. The dispensing circuit permits a selectable amount of energy to be dispensed in the oscillatory tank to adjust the line voltage level by adding the energy to either buck or boost the line voltage as determined by the difference signal.

Abstract: A series type ferroresonant regulator is modified by adding a second ferro-capacitor in parallel with the primary winding of the saturating transformer. This arrangement allows the transformer to operate at a much cooler temperature than is possible with a conventional series ferroresonant regulator of the same power rating.

Abstract: A fault detection system for use in power supply systems using ferro-resonant transformers is presented. Current sensing means are used to sense the current flowing in the ferro-resonant circuit associated with operation of the ferro-resonant transformer. A fault detection circuit, powered by its own power supply connected to the primary source of power, monitors the sensed current and signals any significant change therein. A fault condition in any of the secondary circuits of the transformer causes the ferro-resonant current to change, and upon sensing this change, the fault detection circuit disconnects the primary of the transformer from the source of power.

Abstract: The invention is a controlled ferroresonant power supply with an improved feedback circuit resulting in improved output stability. The feedback circuit is responsive to the low voltage secondary output of the power supply to provide a variable output signal to activate the switch which controls the resonant winding circuit. The improved feedback circuit is responsive to the rectified AC low voltage secondary output for only a portion of its frequency period.

Abstract: A stabilization circuit is provided for use with a ferroresonant power supply to maintain a steady output voltage during power line transients, rapid load changes, or no load condition. The stabilization circuit is responsive to the voltage output of the power supply and selectively connects a load across voltage output terminals. Stabilization circuit includes a voltage sensing circuit that enables a timing circuit that activates a switch to place the load across terminals. This stabilizes the power supply, without requiring a continuously dissipative minimum load.

Abstract: A voltage regulator using a saturable transformer comprises a transformer having a primary and secondary windings, an AC power source for supplying the primary winding a fluctuating alternating current, and a rectifier connected to the secondary winding for rectifying an AC voltage derived therefrom to produce a DC output voltage. The transformer includes a core having four legs and two common portions magnetically joining the four legs, and a control winding supplied with DC control bias from a control circuit. The primary and secondary windings are wound on the first and second legs and the control winding is wound on the first and third legs.

Abstract: A generally figure-of-eight transformer core carries first, second and third toroidal windings spaced along its central leg and is formed with magnetic shunts across the gaps between central and outside legs in the planes between windings. A capacitor is connected across the second winding of value so that it coacts with the effective leakage reactances provided by the magnetic shunts so that the output load current provided by the third winding is directly proportional to the input voltage applied across the first winding independently of the load impedance and with low distortion, even in the presence of high harmonic content in the input voltage and a nonlinear load impedance.

Abstract: A rectifier unit for supplying power to a D.C. load including a transformer having a primary, a secondary and a saturable core, the secondary defining an output section and a control section. A ferroresonance control circuit simulates saturation of the transformer core and includes an electronic switch for controlling the degree of simulated core saturation and thereby regulating the rectifier unit output. Rectifier failure alarm circuitry produces a failure alarm in response to a number of rectifier unit malfunctions. The rectifier failure alarm circuitry is coupled to the ferroresonance control circuitry and comprises a rectifier alarm element operable between the first condition wherein a rectifier failure alarm is produced and a second condition. The failure alarm element is operated from its first condition when the electronic switch minimizes the rectifier system output.

Abstract: Shunt regulation for a high-voltage circuit including a ferroresonant transformer has control circuitry associated with a low-voltage control winding on the transformer, the control winding being magnetically coupled with the high-voltage secondary winding thereof. The control circuitry includes a zener diode for clamping peak voltages on the control winding and a sub-circuit including a voltage-divider and a capacitor. An averaged voltage from the divider/capacitor is compared with a reference by a comparator. Both the comparator and the zener diode serve to turn on a transistor connected across the control winding output, thereby allowing current to flow through the control winding, dropping the output voltage thereof. Regulation of the output voltage on the transformer high-voltage secondary results.