Abstract: A leakage transformer is provided. The leakage transformer includes a first plate, a second plate, a plurality of winding pillars, a primary winding, a secondary winding and a plurality of magnetic shunt elements. Each magnetic shunt element is disposed between the two corresponding winding pillars, and there is a gap between every two neighboring magnetic shunt elements. Alternatively, the magnetic shunt element is disposed on the first plate and aligned with the corresponding winding pillar, and there is a gap between the magnetic shunt element and the second plate. A leakage inductance of the leakage transformer is determined by the gap.

Abstract: A current transformer (10) includes a magnetic core, a first primary-side winding, a second primary-side winding, and a first secondary-side winding. The magnetic core includes a first magnetic core structure, a second magnetic core structure, and a third magnetic core structure. The first magnetic core structure is connected to the second magnetic core structure to constitute a first closed magnetic circuit, the first magnetic core structure is connected to the third magnetic core structure to constitute a second closed magnetic circuit, and the first magnetic core structure is a magnetic core structure common to the first closed magnetic circuit and the second closed magnetic circuit.

Abstract: Embodiments described herein are directed to an energy-harvesting circuit configured to harvest energy from a power converter circuit within a switch mode power supply and generate a positive, a negative or a bipolar power supply rail to power load circuitry. The energy-harvesting circuit includes a transformer, a coupling capacitor, a diode and a capacitor. The transformer has a primary winding, a secondary winding and a magnetic core shared therebetween. The primary winding is electrically connected between a drain and a source of a transistor switch connected to the power converter circuit. The coupling capacitor is electrically connected between the drain and the primary winding and configured to provide a reset mechanism for the magnetic core. The anode of the diode is electrically connected to the secondary winding. The capacitor is electrically connected in series with the cathode of the diode and in parallel with the load circuitry.

Abstract: The invention related to an integrated magnetic component for a switched mode power converter. The integrated magnetic component comprises a single magnetic core structure formed by magnetic core elements, wherein at least one of the magnetic core elements is a leg-core-element with a flange and one or more legs are arranged on one side of the flange. The magnetic core elements of the single magnetic core structure are linearly stacked. The integrated magnetic component further comprises an isolating transformer with a higher current transformer winding arranged on at least one leg of the magnetic core elements, a lower current transformer winding arranged on at least one leg of the magnetic core elements and a first filter inductor comprising a first filter winding, arranged on at least one leg of the magnetic core elements. Herein the higher current transformer winding and the filter winding comprise at least an edgewise wound winding part. The invention further relates to a switched mode power converter.

Abstract: Methods and apparatuses, including computer program code are disclosed herein that provide adaptive battery protection. A method includes disabling a timer, when a current drawn by a battery-powered device from a battery is less than or equal to a lower current threshold. When the timer is disabled, the battery may remain connected to the battery-powered device. The method further includes enabling the timer when the current drawn from the battery is greater than the lower current threshold and less than an extended current threshold. When the timer is enabled, the timer may allow the battery to remain connected to the battery-powered device until the timer expires. The method further includes disconnecting the battery when the timer expires or when the current drawn from the battery exceeds the extended current threshold.

Abstract: A single direct current (DC)-DC converter may include a switching part switching an input DC voltage; first and second transforming parts transforming an output of the switching part; a rectifying part rectifying outputs of each of the first and second transforming parts; and an output part filtering and outputting an output of the rectifying part.

Abstract: A high-frequency oscillator includes an electric resonant circuit, and a high-frequency welding system and a method for controlling the frequency uses a high-frequency oscillator, in particular in a high-frequency welding system. The electric resonant circuit includes at least one electronic component having an inductance and at least one capacitor having a capacitance. At least one additional magnetic coil is associated with the electronic component and can electronically influence the inductance of the electronic component.

Abstract: A filter assembly for a high-voltage connector is disclosed. The filter assembly has a first and a second bus bar, a filter circuit disposed on a circuit carrier, a ring core, and a filter housing. Each bus bar has a first terminal section, a second terminal section, and a connecting section between the first terminal section and the second terminal section. The filter circuit, the ring core, and at least a part of the first and second bus bars are disposed in the filter housing. The first and second bus bars extend substantially parallel to each other and through the ring core. The circuit carrier is disposed in a region of the filter housing in which the connecting section of each of the first and second bus bars is accommodated.

Abstract: An insulating component having a first core accommodating section that receives a first magnetic body core, a second core accommodating section that receives a second magnetic body core, and a locking section. The first core accommodating section has two parallel core leg section accommodating sections that individually surround one of at least two leg sections of the first magnetic body core. The second core accommodating section is configured to surround the second magnetic body core. An aperture section is formed in the insulating component between the two parallel core leg section accommodating sections. The locking section is configured to be locked to a bus bar inserted into that aperture section.

Abstract: A magnetoelectric device includes at least one reluctance component, at least one damping capacitor, and a switching circuit. The reluctance component includes a capacitive and inductive magnetic core unit having a loop-shaped first segment and a second segment connected to the first segment, and at least one coil wound around and loosely coupled to the magnetic core unit. The damping capacitor cooperates with the coil to form a resonant circuit. The switching circuit makes and breaks electrical connection between the coil and a DC power source so that an eddy current flowing through the resonant circuit may be generated for storing energy in the damping capacitor.

Abstract: The present disclosure is directed to a system and method for improving reactive current response time in a renewable energy power system connected to a power grid. The method includes providing, via a controller of the power system, a permissive logic relating to the power grid. Another step includes determining, via a controller of the renewable energy power system, a reactive current reference command for the renewable energy power system in response to the permissive logic being satisfied. The method also includes generating, via the controller, a reactive current pulse command for the renewable energy power system. Thus, the controller is configured to determine a total reactive current command by combining the reactive current reference command and the reactive current pulse command. Further, the method includes operating the renewable energy power system based on the total reactive current command so as to improve the current response time.

Abstract: A transformer includes a plurality of high-voltage side coils and a plurality of low-voltage side coils. The high-voltage side coils and the corresponding low-voltage side coils form a plurality of coil groups. A first coil group includes one of the high-voltage side coils and one of the low-voltage side coils wound around a first leg and one of the high-voltage side coils and one of the low-voltage side coils wound around a second leg adjacent to the first leg. A second coil group of the plurality of coil groups includes one of the high-voltage side coils and one of the low-voltage side coils wound around the first leg, and one of the high-voltage side coils and one of the low-voltage side coils wound around the second leg.

Abstract: An inductor apparatus includes an inductor winding, a core defining a magnetic circuit for a magnetic flux generated by a current flowing through the inductor winding, at least one permanent magnet magnetically biasing the core by its permanent magnetization, and a magnetization device operable for adjusting a desired magnetization of the permanent magnet. The at least one permanent magnet is arranged within the magnetic circuit of the magnetic flux generated by the current flowing through the inductor winding. The magnetization device includes a magnetization winding and a circuitry configured to subject the magnetization winding to magnetization current pulses, thereby generating at a location of the permanent magnet a magnetic field which is able to change the permanent magnetization of the permanent magnet.

Abstract: An electromagnetic device may include a magnetic flux core and an opening through the magnetic flux core. A conductor winding may be received in the opening and extend through the magnetic flux core. An electrical current flowing through the conductor winding generates a magnetic field about the conductor winding and a magnetic flux flow about the opening in the magnetic flux core. The electromagnetic device may also include a core flux sensor arrangement to detect a magnetic flux level in the magnetic flux core. The electromagnetic device may additionally include a core flux control system configured to adjust the electrical current flowing through the conductor winding to control the magnetic flux level in the magnetic flux core.

Abstract: A magnetic integration double-ended converter with an integrated function of a transformer and an inductor includes an integrated magnetic member having a magnetic core with three magnetic columns having at least three windings (NP, NS1, NS2) and at least one energy storage air gap, where a primary winding (NP) and a first secondary winding (NS1) are both wound around a first magnetic column or are both wound around a second magnetic column and a third magnetic column, and a second secondary winding (NS2) is wound around the second magnetic column; an inverter circuit with double ends symmetrically working, acting on the primary winding (NP); and a group of synchronous rectifiers (SR1, SR2), gate electrode driving signals of which and gate electrode driving signals of a group of power switch diodes (S1, S2) of the inverter circuit with the double ends symmetrically working complement each other.

Abstract: An isolated power converter that includes, in one embodiment, a first magnetic core having a primary winding and a secondary winding around the first magnetic core. The power converter includes a second magnetic core having a first leg, a second leg coupled to the first leg, and a third leg coupled to the first and second legs, wherein a part of the third leg is equidistant from the first leg and the second leg. The power converter also includes a first winding encircling the first leg, a first end of the first winding coupled to the secondary winding, a second winding encircling the second leg, a first end of the second winding coupled to the secondary winding, and a third winding encircling the third leg, a first end of the third winding coupled to a second end of the first winding and to a second end of the second winding.

Abstract: An apparatus is disclosed for simultaneously measuring the rotational speed and/or direction of a shaft, and providing control power in accordance with the shaft rotation. The apparatus includes a permanent magnet machine (PMM) having a multipole rotor and a stator. The rotor has a plurality of permanent magnet poles and connection to the rotating shaft; the stator includes a winding and electrical connections, so that motion of the rotor with respect to the stator causes a voltage signal at the electrical connections. The apparatus also includes a circuit including a power conversion portion and a speed/direction sensing portion. The circuit receives the voltage signal from the PMM, and simultaneously outputs control power from the power conversion portion and a signal indicating the rotational speed and/or direction of the shaft from the sensing portion.

Abstract: An insulation transformer and a key input circuit having the same are disclosed. The insulation transformer includes: a core having a certain gap; and primary and secondary coils wound on the core. According to the insulation transformer, the operation deficiency of the insulation transformer can be reduced and thus the signal transmission efficiency can be improved. Also, the key input circuit including: an insulation transformer includes a core having a certain gap, and primary and secondary coils wound on the core; a microcomputer connected with the primary coil; and a key input unit connected with the secondary coil and including multiple resistors and switches. According to the key input circuit having the insulation transformer, the reliability of the operation of the key input circuit can be improved and user inconvenience that may be caused by an operation error can be prevented.

Abstract: There are provided an integrated transformer in which a power conversion transformer and an inductor for stabilizing output power by the transformer are integrated into one transformer structure, and a power supply using the same. An integrated transformer according to an aspect of the invention includes: a core part including: first and second supports; and first and second outer legs and a center leg provided between the first and second supports, and magnetically connecting the first and second supports to each other, wherein a cross-section of the first and second outer legs and a cross-section of the center leg have a width of the first support and a width of the second support in a longitudinal direction, respectively, and a width of each of the first and second outer legs exceeds 0.5 times a width of the center leg but does not exceed 2 times the width of the center leg.

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 micro-transformer manufacturing method is provided, which can improve throughput, prevent a crack from entering an insulating film between coils, and manufacture the micro-transformer without using a mask material having a high selection ratio. An insulating film is deposited on the whole face of a semiconductor substrate having an impurity-diffused region. This insulating film is partially removed to form a first opening and a second opening. A primary coil is formed such that a center pad contacts the impurity-diffused region through the first opening. A thin insulating film is deposited on the primary coil. An insulator material having a secondary coil formed thereon is adhered onto the insulating film on the primary coil by adhesive tape. The insulator material is sized to not cover both a pad, connected with the center pad of the primary coil through the impurity-diffused region, and an outer-end pad of the primary coil.

Abstract: In order to reduce the cost of a chopping converter supplying a continuous voltage at the terminals of a load (Z), a circuit with two windings (Lp, Ls) and a single magnetic core is proposed, according to the present invention, which enables the cost and the size of the circuit to be reduced. It is then necessary to add two diodes (D3, D4) to the circuit, but these elements are inexpensive and of small size.

Abstract: In order to reduce the cost of a chopping converter supplying a continuous voltage at the terminals of a load (Z), a circuit with three windings (Lp, Ls1, Ls2) and a single magnetic core is proposed, according to the present invention, which enables the cost and the size of the circuit to be reduced. It is then necessary to add two diodes (D3, D4) to the circuit, but these elements are of low cost and of low size.

Abstract: A wiring arrangement and an appliance for limiting the harmonics of a current supplied to a frequency converter from an AC electricity supply network, which frequency converter can be connected to a three-phase AC electricity supply network, in which frequency converter is an uncontrolled network bridge (10) for rectifying the AC voltage of the AC electricity supply network, a DC intermediate circuit, in which is a filtering capacitor (CDC), and a load bridge (11) provided with power semiconductor switches for forming three-phase AC voltage (U, V, W), and which load bridge can be controlled with pulse-width modulation by means of a control unit, and in which DC intermediate circuit is a choke, in which is a choke part (L1, L2) arranged on both the positive and the negative pole, and in which wiring arrangement is an absorption circuit for limiting the harmonics of the current supplied from the AC electricity supply network, in which the absorption circuit is arranged in the DC intermediate voltage circuit,

Abstract: A switching power supply includes: a first series circuit, connected to both terminals of a direct current power supply Vdc1, in which a primary winding 5a of a transformer T, a reactor L3 and a first switch Q1 are connected in series; a second series circuit, connected to both terminals of the primary winding 5a and the reactor L3, which includes a switch Q2 and a capacitor C3; a smoothing circuit D1, D2, L1, C4; and a control circuit 10 alternately turning on and turning off the switches Q1, Q2. The transformer T includes: a main core 21, formed with a magnetic circuit, on which the primary and secondary windings 5a, 5b are wound with a given gap 23; and a plurality of auxiliary cores 24a, 24b disposed in the given gap 23 with a given distance in a circumferential direction of the primary winding 5a. Further, the reactor L3 is formed of a leakage inductance of the transformer T.

Abstract: Power electronics equipment includes a switching device directing current flow to a load and interrupting the current flowing to the load, a control circuit generating a control signal directing the conduction and non-conduction of the switching device, a driver circuit driving a control terminal of the switching device based on the control signal, and at least one air-cored insulating transformer insulating the control circuit and the driver circuit from each other. Each air-cored insulating transformer includes a primary winding and a secondary winding configured to generate a voltage by a change of interlinkage of a magnetic field. The secondary winding includes a plurality of coils configured such that voltages generated by external magnetic flux intersecting the secondary winding are canceled and a voltage generated by the signal magnetic flux intersecting the secondary winding is increased.

Abstract: An inverter transformer includes: a frame-core shaped substantially square; a plurality of I-cores disposed inside and coupled to the frame-core so as to provide a predetermined leakage inductance; and a plurality of primary and secondary windings provided respectively around the I-cores. The I-cores are divided into first group cores located not adjacent to one another and second group cores located not adjacent to one another but adjacent respectively to the first group cores. Magnetic fluxes generated in the first group cores flow in the same direction, magnetic fluxes generated in the second group cores flow in the same direction that is opposite to the direction of the magnetic fluxes generated in the first group cores, and respective voltages induced at secondary windings provided respectively around the first and second group cores are polarized identical with each other.

Abstract: The switched-mode power supply according to the invention has a power factor correction circuit, which operates on the principle of a current pump and has a first coil (L15) for damping voltage spikes, as well as a second coil (L19) for power factor correction. The two inductances (L15, L19) are in this case connected in series and are arranged on a coil former (SK) and on a common core (CR). In one preferred exemplary embodiment, an E/E ferrite core is used as the core (CR), and a coil former with chambers is used as the coil former (SK), with the windings (W15, W19) of the two inductances (L15, L19) being arranged in different chambers (K1, K3, K4). An empty chamber (K2), which is located in the region of the air gap (AG) in the core (CR), is advantageously arranged between the two inductances. This partially decouples the two inductances by means of the air gap, so that the damping response of the first inductance (L15) is better.

Abstract: An inverter transformer is provided which can turn on a plurality of cold cathode fluorescent lamps (CFLs) with a minimized increase in the number of components, thereby reducing costs. The inverter transformer comprises a plurality of bobbins for windings. The plurality of bobbins each having a secondary winding wound thereon and having a bar-shaped inner core inserted therein are connected to one another for integration, and a primary winding is wound in common on the bobbins connected together. A plurality of inner cores and a rectangular frame-shaped outer core are magnetically coupled with each other with non-magnetic sheets interposed therebetween to provide a predetermined leakage inductance. A plurality of CFLs can be turned on with only one outer core, thereby reducing the number of components, downsizing the device, and reducing the cost.

Abstract: A reactance coil (1) has an annular core (2) on which reactance coils are wound. Said reactance coils (3) are divided up into coil sectors 6 (4) that are separated from each other by means of gaps (5) in the windings. The gaps (5) in the windings reduce reactance coil (3) capacity and the reactance coils (3) have resonances with higher maximum values for impedance and greater bandwidths.

Abstract: In an inverter transformer, since a plurality of secondary windings 2, 2 are wound around a plurality of bar-shaped magnetic cores 3, 3 which are formed independently of each other and electromagnetically coupled to a primary winding 1 with equivalent characteristics, there are obtained a plurality of secondary windings 2, 2 which function independently of each other and are electromagnetically equivalent to each other as well, and an open magnetic circuit structure. It does not happen that the numbers of both the primary and secondary winding increase in proportion to the increase in the number of cold cathode lamps, but only the number of the secondary winding increases while the primary winding is common and does not increase in number.

Abstract: The electrical machine, especially a three-phase generator, has a stationary stator (21); a rotatable rotor having an excitation coil (28), a rotary transformer (29) having a primary winding (30) and a secondary winding (31) on respective soft ferrite cores and magnetically coupled with each other via an air gap (38) and a control circuit (40) for loading the primary winding (30) of the rotary transformer (29) with an alternating current. The control circuit (40) includes an input-side current limiting circuit (46), whereby an integrated temperature control is obtained in cooperation with the soft ferrite cores of the primary and secondary windings according to the Curie effect.

Abstract: A fluorescent lamp ballast utilizes a single a transformer for providing both tank inductance and current mode feedback to the ballast driver circuitry. The transformer has an "EE" core with inductor windings on the center legs and gate windings on one of the outer legs. The center leg is gapped to avoid magnetic core saturation and to adjust inductance to a desired value. Coupling can be adjusted further by gapping one or the other of the outer legs.

Abstract: DC power is converted by an inverter to high-frequency power, which is supplied to the primary winding of a neon transformer. One or more neon tubes are connected in series across the secondary winding of the neon transformer. A saturable reactor is connected across the secondary winding or the neon transformer. The saturable reactor has a characteristic that its magnetic flux is saturated when the output voltage from the secondary winding of the neon transformer increases 1.1 to 2.0 times the rated voltage.

Abstract: An operator controllable transformer having a shunt magnetic path with a control coil is provided. The transformer includes phase control circuitry to control the output of the transformer by phase controlling current flow in the shunt coil, thereby controlling the flux through the shunt magnetic path and the flux coupling with the secondary coil. Power for the control circuitry is derived from the current induced in the shunt coil.

Abstract: The invention provides an electrophoresis system which separates charged chemical substances by means of applying an electrical potential across a buffer solution which includes those chemical substances. The system of the invention includes a power supply and control system which has a wide dynamic range of constant voltage, current and power which may be supplied, and is therefore particularly suited to the needs of the electrophoresis system. In the invention, the power supply includes a flyback topology and a control system which allows an operator to specify a wide range of constant voltage, current or power supply requirements for the electrophoresis system.

Abstract: A transformer having a shunt magnetic path and a shunt coil is provided. The transformer includes control circuitry to control the output of the transformer by controlling current flow in the shunt coil, thereby controlling the flux through the shunt magnetic path and the flux coupling with the secondary coil. The current in the shunt coil is phase-controlled and power for the control circuitry is derived from the current induced in the shunt coil.

Abstract: A dual mold choke is provided to reduce both differential and common mode electromagnetic interference. Ferrite cores are placed around DC power bus bars providing an inductor limiting differential mode noise and creating a choke reducing common mode noise. The use of E-cores provides a simplified mechanical assembly while providing high levels of noise reduction. An air gap between the center legs of the cores prevents saturation of the choke.

Abstract: A two switch, DC/DC converter provides sufficient inductive energy storage at the termination of the "on" period of each switch to alter the charge on the intrinsic and stray capacitance of the combination of switches producing zero voltage across the alternate switch prior to its turn on. A short dead-band between the turn on pulses provided by the control circuit allows time for this transition. Thus the energy stored in the capacitance of the switches is returned to the source and load rather than being dissipated in the switching devices. This greatly improves the efficiency of the converter particularly when operating at high frequency. The unique topology of the converter provides other new and useful characteristics in addition to zero voltage switching capability such as operation as constant frequency with pulse-width-modulation for regulation, quasi-square wave output current, and the ability to integrate the magnetic elements with or without coupling.

Abstract: A power source apparatus includes a transformer having a plurality of paired winding portions of primary and secondary windings wound around cores divided by a gap, a driver, connected to the primary winding of the paired winding portion, for switching energization of the primary winding of the transformer to generate a secondary winding voltage, and a selector for selectively driving one of the plurality of paired winding portions.

Abstract: A two switch, DC/DC converter provides sufficient inductive energy storage at the termination of the "on" period of each switch to alter the charge on the intrinsic and stray capacitance of the combination of switches producing zero voltage across the alternate switch prior to its turn on. A short dead-band between the turn on pulses provided by the control circuit allows time for this transition. Thus the energy stored in the capacitance of the switches is returned to the source and load rather than being dissipated in the switching devices. This greatly improves the efficiency of the converter particularly when operating at high frequency. The unique topology of the converter provides other new and useful characteristics in addition to zero voltage switching capaibility such as operation at constant frequency with pulse-width-modulation for regulation, quasi-square wave output current, and the ability to integrate the magnetic elements with or without coupling.

Abstract: There is provided a low-noise switching power supply for producing a regulated output voltage from an unregulated supply. The power supply includes a main transformer having first, second and third legs. A primary winding associated with a first leg produces an alternating magnetic flux in the core. A load winding associated with a second leg produces the output voltage from the power supply. A control winding is associated with the third leg. The regulated output voltage is compared to a reference voltage and used to operate a control circuit which alternately short circuits the control winding so as to vary the reluctance pass in the transformer and maintain the output voltage at a substantially constant predetermined value. A feedback circuit including a coupling transformer connects the primary coil to the switching circuit to improve regulation and provide a "soft start" capability.

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: Two ferromagnetic cores (11, 12) are provided for a transformer, only one of the cores (11) exhibits an air gap (13) in which a Hall effect element (3) is housed. The current flowing in a conductor (10) can be direct or alternating current and induces in the core (11) a corresponding magnetic field which makes it possible to obtain a signal on the element (3). This signal is amplified by an amplifier (8). The output current from amplifier (8) is applied to a winding wound around both cores (11, 12). For direct current and low frequency current, the winding current is proportional to the current in conductor (10). When the frequency of the current flowing through conductor (10) exceeds a certain value (several kHz), the gain of the amplifier (8) diminishes. A linear relationship between the conductor current and the current in the winding is maintained, however, because the high frequency is transmitted to the winding by the core (12).

Abstract: An AND function gating circuit for A.C. signals comprising several magnetic circuits around a common limb, each circuit having a separate input winding and a single output winding on the common limb. The magnetic flux level in the common limb is greatly increased when all input windings are simultaneously energized by A.C. signals of the same frequency and in phase relative to the output achieved under other input signal conditions.

Abstract: A rotating flux transformer having at least two magnetic cores, each in the form of a torus, with each magnetic core having poloidal and toroidal windings. The need for breaking the torus and bringing out leads from the poloidal winding is eliminated by passing each torus through the core window of the remaining torus, or tori. Each poloidal winding is shorted, with the toroidal winding, or windings, of the other magnetic core or cores, inducing an excitation voltage into each shorted poloidal winding which is 90.degree. out of phase with the voltage applied to the toroidal winding on the same magnetic core.

Abstract: A rotating flux transformer which includes a magnetic core having poloidal primary and secondary windings and toroidal primary and secondary windings. Quadrature flux is produced in the magnetic core by connecting one end of the poloidal primary winding to the center of the toroidal primary winding. The quadrature flux combines vectorially to produce a rotating induction vector in the magnetic core.

Abstract: An electric power apparatus, namely a variable inductor comprising a magnetic core provided with a center limb and two outer limbs all having first and second ends. The first ends are interconnected through a first common point of the magnetic core, and the second ends through a second common point of this core. Two primary windings disposed respectively around the two outer limbs are connected in series and supplied with an alternating current, while two control windings also connected in series are respectively superposed to the two primary windings. The alternating current of the primary windings is rectified through a diode bridge for supplying with direct current the control windings.

Abstract: A control system for driving a variable speed AC motor employing a fixed frequency AC power source, combines pulses representative of a desired slip frequency with pulses of a frequency proportional to the speed of the motor. The combined pulses are employed with a speed command signal to set a threshold which determines the fraction of each cycle of the AC primary power which is fed to the motor. In addition, the speed and slip pulses are employed to direct the AC power to specific ones of the windings of the motor to thereby create a rotating magnetic field in the induction motor. An array of silicon-controlled rectifiers does the actual gating and an SCR protect circuit ensures that transfer of control from one SCR to another is inhibited until all current ceases to flow in an SCR being extinguished. A forced commutation circuit forces the extinction of all current remaining in the last conducting SCR feeding a motor winding at the transfer time from that motor winding to the next.

Abstract: A novel transformer is described for use in a static inverter in association with one or two switching semiconductor devices. The transformer produces an output for control of the associated switching device(s) which changes in sense from conduction aiding to conduction inhibiting as a function of the flux level in the transformer core. The invention is applicable to single loop cores, such as are assembled from two "U" cores. Control is effected by a primary and secondary control winding wound through an aperture pair, the aperture pair being oriented for "neutrality" of the second control winding to the main flux. The aperture pair creates a five branch magnetic path which permits optimizing the control voltage applied to the associated semiconductor devices both to enhance the switching efficiency when the switching device is initially turned on and to reduce stresses on the switching device by precluding transformer saturation when the switching device is turned off.