Abstract: The present application discloses a current equalizing busbar for a converter comprising: a direct current busbar connected to a DC terminal of the converter and positive terminals and negative terminals of respective power modules; and an alternate current busbar connected to AC terminals of the respective power modules and a load; wherein, when the converter operates, a sum of an inductance caused by the DC busbar between the DC terminal and a positive terminal or a negative terminal of a power module and an inductance caused by the AC busbar between the load and an AC terminal of the power module is equal to a sum of an inductance caused by the DC busbar between the DC terminal and positive terminals or negative terminals of other power modules and an inductance caused by the AC busbar between the load and AC terminals of said other power modules.

Abstract: An integrated magnetic device for low harmonics three-phase front-end (1) comprising three magnetic sub-assemblies (30), wherein each magnetic sub-assembly (30) comprises a magnetic core without air-gaps, three or more wound limbs and at least five windings, three current inputs connectable to a three-phase power grid (100), at least nine current outputs, three for each current inputs, said current outputs being galvanically connected to said three current inputs and connectable to a load (200). The integrated magnetic device is designed for a low harmonics three-phase bidirectional front-end and also for AC/DC rectifier and DC/AC power inverters. Its use enables reduction of the harmonics of the currents absorbed or injected to three-phase power line by using only one device which integrates a splitter and an inductor function. Compared to known solutions, cost, material and dimensions of the integrated magnetic device are reduced.

Abstract: Method and apparatus for controlling an apparatus transmitting power between two electricity networks or between an electricity network and a polyphase electric machine), and including low-voltage power cells (C), which include a single-phase input/output connection (IN/OUT). The power cells are arranged into groups (G1-GN, GP1-GPN1, GS1-GSN2, G1??-GN??) such that at least one power cell per each phase of the electricity network or of the electric machine belongs to each group, and the input terminals (IN) of all the power cells belonging to the same group are connected to a common transformer, the transformer including its own separate winding that is galvanically isolated. The controllable power semiconductor switches connected to the input connectors (IN) of all the power cells supplying power to the same transformer are controlled cophasally with a 50% pulse ratio.

Abstract: Embodiments of the present invention provide novel techniques for using multiple 18-pulse rectifier circuits in parallel. In particular, each rectifier circuit may include an autotransformer having 15 inductors coupled in series, joined by 15 nodes interposed between pairs of the inductors. The inductors may be represented as a hexagon in which alternating sides of the hexagon have two and three inductors, respectively. Each rectifier circuit may also include three inputs for three-phase AC power coupled to alternating vertices of the hexagonal representation and nine outputs for AC power coupled between each node that is not a vertex of the hexagonal representation and a respective diode bridge. Outputs of the diode bridges for the rectifier circuits may be coupled to a DC bus. In addition, a means for reducing circulating current between the parallel rectifier circuits and for promoting load sharing between the parallel rectifier circuits is also provided.

Abstract: A 24-pulse composite AC-to-DC converter is a converter using two or more conversion methods in parallel. The converter may include a main rectifier receiving at least a portion of an input AC signal, an autotransformer having an output voltage with lower amplitude than the input AC signal, and a plurality of auxiliary bridge rectifiers, each receiving the output from each leg of the autotransformer. In one embodiment of the invention, the main rectifier may receive a substantial portion of the load current, allowing each of the auxiliary bridge rectifiers to be generally smaller than the main rectifier.

Abstract: Techniques for using multiple 18-pulse rectifier circuits in parallel are described herein. In particular, each rectifier circuit may include an autotransformer having 15 inductors coupled in series, joined by 15 nodes interposed between pairs of the inductors. The inductors may be represented as a hexagon in which alternating sides of the hexagon have two and three inductors, respectively. Each rectifier circuit may also include three inputs for three-phase AC power coupled to alternating vertices of the hexagonal representation and nine outputs for AC power coupled between each node that is not a vertex of the hexagonal representation and a respective diode bridge. Outputs of the diode bridges for the rectifier circuits may be coupled to a DC bus. In addition, a means for reducing circulating current between the parallel rectifier circuits and for promoting load sharing between the parallel rectifier circuits is also provided.

Abstract: Each voltage converting unit outputs a first signal at a first output and second signal at a second output. Each first transforming unit includes a magnetically coupled primary and secondary coil, the first output of each one of the converting units is connected to a primary coil of a different one of the first transforming units, the primary coil of each one of the first transforming units is electrically connected to one secondary coil of another one of the first transforming units. Each second transforming units includes a magnetically coupled primary and a secondary coil, the second output of each one of the voltage converting units is connected to a primary coil of a different one of the second transforming units, the primary coil of each one of the second transforming units is electrically connected to one secondary coil of another one of the second transforming units.

Abstract: Embodiments of the present invention provide novel techniques for using multiple 18-pulse rectifier circuits in parallel. In particular, each rectifier circuit may include an autotransformer having 15 inductors coupled in series, joined by 15 nodes interposed between pairs of the inductors. The inductors may be represented as a hexagon in which alternating sides of the hexagon have two and three inductors, respectively. Each rectifier circuit may also include three inputs for three-phase AC power coupled to alternating vertices of the hexagonal representation and nine outputs for AC power coupled between each node that is not a vertex of the hexagonal representation and a respective diode bridge. Outputs of the diode bridges for the rectifier circuits may be coupled to a DC bus. In addition, a means for reducing circulating current between the parallel rectifier circuits and for promoting load sharing between the parallel rectifier circuits is also provided.

Abstract: The invention relates to the electrical power supply of aircraft and notably of large commercial aircraft. According to the invention, the aircraft is equipped with an AC-DC converter that distributes power over a DC network starting from a three-phase alternating voltage of 230 volts applied to its main inputs (E1, E2, E3). The converter comprises an autotransformer which preferably has nine outputs (A1, A2, A3, B1, B2, etc.) for a nine-phase rectification. These outputs are applied to a rectifier bridge with 18 diodes. When the aircraft is on the ground, the AC power is delivered at 115 volts from a ground generator; it is applied via a three-phase connector (CAUX) to auxiliary inputs (M1, M2, M3) connected to intermediate taps of the three-phase windings forming the AC-DC converter.

Abstract: Various embodiments of multi-phase transformers are disclosed. Exemplary transformer includes primary windings, secondary windings and third windings. Primary windings, secondary windings and third windings may include sub windings coupled to form functions. Primary windings are coupled at ends to form a delta configurations. Secondary windings are coupled to primary windings. Third windings are coupled to primary windings and secondary windings. Secondary windings and the third windings are magnetically coupled to primary windings. The outputs at second ends of third windings are greater than the outputs at the second ends of secondary windings. In some embodiments, the outputs at adjacent second ends of the third windings are substantially equal. In some embodiments, the phase angle difference of outputs at adjacent second ends of third windings are substantially equal. In some embodiments, the phase angle difference of outputs at adjacent second ends of secondary windings are substantial equal.

Abstract: Power conversion systems and methods are provided for driving a plurality of motor loads, in which an autotransformer receives AC input currents and provides a plurality of multiphase outputs at a non-zero phase angle relative to one another, and the individual multiphase outputs are provided to corresponding motor drives with rectifiers to convert the multiphase outputs to DC electrical power, and inverters to convert the DC power to AC to drive corresponding motor loads.

Abstract: A polygon connected three-phase autotransformer using nine windings per phase provides a reduced power rating fifteen-phase power source suitable for 30-pulse AC to DC power converters. The windings are selected and connected in a manner that accommodates zero-sequence currents, such as the third harmonic, and minimizes total kVA rating. When the autotransformer is used to power a 15-phase AC to DC converter its kVA rating is typically less than 51% of the DC load kW. AC line current distortion is negligible and can satisfy the most exacting practical harmonic specifications. Additional isolated windings can provide means for the invention to operate as an efficient double-wound transformer.

Abstract: The invention relates to an autotransformer for transforming a three-phase power supply into a nine-phase power supply, notably for use in a rectifier. The autotransformer is a, step-up or step-down transformer. For a step-down application, the three-phase input terminals E1, E2, E3 are connected to one of the three main windings in delta configuration, mounted on respective magnetic branches M12, M23, M31 of a magnetic circuit. Te main winding B12 of one branch has intermediate taps K1, K?1, K?1 from which auxiliary windings X31, Y23, Z31, mounted on the other branches, start. These auxiliary windings produce, on three output terminals A1, B1, C1, voltages one of which is in phase with the three-phase supply voltage at E1, the other phase-shifted by +40°, and the third by +80°. The number of turns in the auxiliary windings and the position of the intermediate taps are calculated so as to obtain this result.

Abstract: The rectification stage (18) having: an autotransformer (40) for twelve-phase rectification; two rectifiers (50A, 50B) each of which is connected at the input to three separate phases of the autotransformer (40); two interphase inductors (51A, 51B); and a filtration stage (54) which receives at the input the centre points of the two interphase inductors (51A, 51B). The two interphase inductors (51A, 51B) have a common core (52) which defines a magnetic circuit and all the windings of the two interphase inductors (51A, 51B) are wound on this common core for the magnetic coupling thereof.

Abstract: The invention provides a 12-pulse converter comprising an autotransformer having a primary winding connected in a delta configuration and two secondary windings connected in star configurations, the two secondary windings being connected to two rectifier bridges that are enabled to operate in parallel by two interphase chokes, the converter further comprising means for generating an additional magnetic leakage flux in at least one of the interphase chokes so as to incorporate a smoothing choke therein.

Abstract: A polyphase generator for medical diathermy apparatus comprises a ferromagnetic ring core bearing two primary windings each of which has two winding portions positioned diametrically opposite one another. The winding portions in each case are connected in series and are wound such that they create opposing magnetic effect which substantially cancel one another. Two primary windings are positioned substantially at right angles to one another. A plurality of secondary windings are arranged on the core to supply output terminals. A direct current supply may be connected via switching means to induce a resonant signal within the primary windings to generate a polyphase output at the terminals for use in application to electrodes of diathermy apparatus operating in excess of 200 kHz.

Abstract: The invention includes a transformer for converting three-phase AC power to nine-phase AC power. An autotransformer includes three coils, each coil including a plurality of serial windings that together form a polygon. Nine output nodes are provided between adjacent winding pairs, the windings sized and arranged such that adjacent output voltages are separated by 40 degree phase shift and such that output voltage magnitudes are essentially identical. Both step-up and unity gain input node sets are provided wherein, when three phase AC supply lines are linked to the step-up input set the output voltage is stepped up and when the three phase AC supply lines are linked to the unity gain input set the transformer gain is unity. An isolation transformer includes a secondary arranged like the autotransformer configuration described above.

Abstract: Three-phase alternating-current electric energy supplied from a primary power supply is supplied to first and second six-phase transformer-coupled rectifying circuits which are connected in cascade to each other. The first six-phase transformer-coupled rectifying circuit comprises three primary windings connected in delta, and the second six-phase transformer-coupled rectifying circuit comprises three primary windings connected in star, for producing respective output voltages which are .pi./6 out of phase with each other. The first and second six-phase transformer-coupled rectifying circuits, which are connected in cascade to each other, jointly provide a twelve-phase rectifying circuit which produces a reduced harmonic or ripple current in its output energy as compared with a six-phase transformer-coupled rectifying circuit. The two six-phase transformer-coupled rectifying circuits share a voltage applied to the power supply device, and hence may have lower requirements for withstanding a breakdown voltage.

Abstract: In 12-pulse and 18-pulse AC/DC converter systems a single wye connected auto transformer using appropriate segments of voltage from each phase connected in fork fashion is used to develop 6-phase and 9-phase voltages in a symmetrical manner such that inherent compensation is made for the dc converter output voltage to be within 4.2% of that of a 6-pulse converter. Additional design adjustments for step-up or step-down of voltage can be made without compromising the transformer symmetry. An unconnected but closed delta winding provides a path in which third harmonic currents, and multiples thereof can flow.

Abstract: A 12-pulse converter of lower rating and minimal current harmonics is obtained with an auto-connected regular hexagon transformer including a delta winding in its center.

Abstract: A three-phase transformer includes six windings, disposed in three pairs, all of which six windings are serially interconnected. A desired turns ratio between the two windings of each pair establishes a desired phase shift between one three-phase output of the connected windings and a second three-phase output of the windings. These two windings can be used in combination to drive a load, such as an induction motor, such as through a twelve pulse rectifier requiring two three-phase outputs out of phase by 30.degree.. Alternately, one of the three-phase outputs can be used to supply the full load of the motor directly. This is particularly useful in a electric submersible pumping system having a three-phase induction motor which is normally operated by a maintenance intensive twelve-pulse rectifier, which motor needs to be directly driven through a by-pass motor controller when the rectifier is in maintenance.

Abstract: An AC/DC or DC/AC converter includes a single hexagon transformer with each side connected to opposite polarity DC terminals through two pairs of SCR devices gated in sequence synchronously with the frequency of the AC lines, gating in a pair lagging gating of the next SCR device in the adjoining pair, to create a 24-pulse output, while minimizing AC line harmonic contents, especially the 11th and 13th harmonics.

Abstract: In a multiphase AC/DC converter system a single transformer is used having phase shifted tappings drawn from a polygonal succession of long and short windings wherein some of the windings carry only the difference between the outputted currents derived from the tappings.

Abstract: A DC/DC power converter 10 which avoids shoot-through current by employing an energy storage fly-back inductor 27 having two separate primary windings 28 and 29, one for current in each direction. The fly-back inductor 27 is located inside the switching bridge. In addition, a transformer 30 having two separate windings 42 and 44 is also employed. Thus, shoot-through is avoided and an extra switch for pulse width modulation is not required. In addition, the device does not apply a greater voltage than the line voltage to the switches and "holes" in the output current are not created so that less noise is generated by the device.

Abstract: Device for supplying power from a three-phase network to an ozonizer comprising at least two discharge elements (3, 4) having a capacitive character, and comprising two single-phase step-up transformers (1, 2) having air gaps connected in a SCOTT circuit and connected between the three-phase network and said discharge elements (3, 4). The device further comprises a three-phase transformer (8) whose secondary windings (5, 6, 7) are connected between said single-phase transformers (1, 2) and the three-phase network and whose primary windings (9, 10, 11) are star-connected and connected to the three-phase network through a dimmer (12).

Abstract: A rectifier transformer for supplying a predetermined alternating current to a rectifier includes: a transformer having secondary windings (cell windings) connected in a double star in such a manner that common terminal side conductors of the secondary windings are individually drawn out; and an interphase reactor having three iron cores, one of which is provided or each individual phase, primary windings formed by passing the conductors connected to two ends of the individual cell windings through the corresponding iron cores, and secondary windings wound around the corresponding iron cores in such a way that they are inductively coupled to the primary windings, the secondary windings being connected to each other in series so as to form a closed circuit.

Abstract: In a 12-pulse AC/DC converter of the hexagon type the rectifier switches are distributed in three groups for each polarity and for each polarity three coils are joined to the common pole and connected separately to the pairs of rectifier switches of a corresponding group. As a result, the capability of the hexagon is extended to commutation of diodes, instead of controlled rectifier switches, by the effect of such interposed commutation inductance.

Abstract: There is disclosed an alternating current to direct current static converter which includes a three-phase transformer interconnected with two rectifier bridges to produce a twelve-phase connection for direct current output. The twelve-phase connection is provided by coupling input terminals of one of the bridges to corresponding primary input terminals of each of the three phases of the transformer, and coupling input terminals of the other of the bridges to corresponding phase terminals of the secondary of the three-phase transformer. The outputs of the rectifier bridges are then coupled to provide the DC output. The transformer is constructed such that there is a 150 degree phase shift between the primary and secondary voltages of each phase of the three-phase transformer and a 30 degree phase shift between the input voltages to the rectifier bridges.