Abstract: A new converter is disclosed, for reducing current harmonics in three phase AC network, during the conversion of AC to DC for power supplying the high-power electrochemical and other non-linear apparatus.

Abstract: The invention relates to an AC/DC converter circuit (100) and a method for converting N?2 AC supply voltages (U1, U2, U3) into DC voltage. This is achieved by feeding the AC supply voltages to first terminals (a1, a2, a3) of full bridge converters (11, 12, 13), wherein the second terminals (b1, b2, b3) of these rectifiers are coupled to each other. The outputs (d11, d1?, d2, d2?, d3, d3?) of the rectifiers are fed to the DC terminals of intermediate converters (21, 22, 23). The AC terminals (e1, e1?, e2, e2?, e3, e3?) of the intermediate converters are connected to the primary sides of transformers (31, 32, 33), wherein the secondary sides of these transformers are provided to further rectifiers (41, 42, 43). The circuit design allows using MosFETs of limited voltage capability for processing 380 V three-phase AC current, thus achieving a high efficiency.

Abstract: A power converter has a transformer having three primary windings configured to receive respective phases of a three-phase alternating current (AC) input signal in a delta configuration and three secondary windings, each split into two portions, wherein the portions are coupled together in a regular hexagon. The power converter includes a rectifier having a first rectifier path coupled between taps of the secondary windings and a positive output of the power converter and a second rectifier path coupled between taps of the secondary windings and a negative output. One of the secondary windings may be reversed with respect to the other secondary windings. The primary windings may be split with a corresponding secondary winding sandwiched between portions of the primary. One of the paths may have a different inductance than the other path.

Abstract: A control apparatus and a control method for an AC electric motor detect DC bus current plural times at predetermined intervals during first and second predetermined periods and multiply vectors having integrated values of detected values during respective periods as elements by an inverse matrix of a matrix having integrated values during respective periods of sine and cosine functions of output voltage phase of an inverter at the moment that detection is made as elements to thereby estimate reactive and active currents.

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: 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: An AC-DC power converter is composed of AC input, a first rectifying circuit, a second rectifying circuit, a DC-DC converter and a DC output. The DC-DC converter has a DC input. The first rectifying circuit and the second rectifying circuit are connected in parallel between the AC input and the DC input of the DC-DC converter. At least one of the rectifying circuits comprises a phase shifting element that provides a phase shift at the AC line frequency.

Abstract: An AC-DC power converter is composed of AC input, a first rectifying circuit, a second rectifying circuit, a DC-DC converter and a DC output. The DC-DC converter has a DC input. The first rectifying circuit and the second rectifying circuit are connected in parallel between the AC input and the DC input of the DC-DC converter. At least one of the rectifying circuits comprises a phase shifting element that provides a phase shift at the AC line frequency.

Abstract: Three coils, each having several serial windings, have selected windings connected in a delta. Input AC power is applied through outrigger windings at the delta apices. At least two strategically located, direct tap, natural output points are provided at each side of the delta. For 6-phase output, only the six natural output points are required. For 9-phase output, an additional central output terminal connects to each side of the delta through a stub winding. The 6-phase or 9-phase output is passed to a rectifier circuit.

Abstract: A circuit producing power with controlled frequency from a variable frequency power source (14) includes an AC bus (20) connected to the variable frequency power source (14) and a plurality of load circuits, each load circuit including an AC input (24) and an AC output (26), an AC contactor (30) between the input (24) and output (26), a rectifier (32) between the AC contactor (30) and the output (26) and an inverter (34) between the rectifier (32) and the output (26). A method of producing power with controlled frequency is also disclosed.

Abstract: Process and device for supplying an electronic circuit and for supplying a power-demanding facility controlled by this circuit, with electrical energy originating from at least two batteries, the electronic circuit comprising battery switching elements adapted to place these batteries in parallel or in series, the facility being subjected to controlled operating phases. The batteries are connected in series or in parallel as a function of their state with respect to two thresholds and the energy-demanding facility is controlled so as to operate according to two modes as a function of the state of the batteries.

Abstract: In a 12-pulse converter system a 3-phase auto transformer with 4 windings per phase is used to power two 6-pulse converter bridges connected in parallel with a large dc filter capacitor. The transformer rating is typically about 40% of the dc kW load. The voltage ratio is typically 1:1 so that the average dc output of a multi-pulse converter is generally the same as that of a conventional 3-phase bridge rectifier without transformer, however, ac input harmonic currents are greatly reduced. A small single-phase transformer is used to block unwanted circulating currents between the two 6-pulse converters. Where necessary to further reduce high frequency harmonic currents, a 3-phase ac line reactor may be connected in series with the source of ac power.

Abstract: In a multi-pulse converter system a three-phase transformer with tapped wye-connected primary winding and isolated delta-connected secondary winding is used to power two 6-pulse converter bridges connected in series to give 12-pulse operation. The transformer equivalent kVA rating is a fraction, typically less than 60%, of the total dc power. By adjusting the tapping on the wye-connected primary winding the converter dc output voltage is readily adjusted to provide higher or lower dc voltage than is attainable by a three-phase 6-pulse converter. By these means a reliable and versatile 12-pulse converter is obtained which, without additional hardware, gives excellent performance in the face of practical power sources which may incorporate voltage unbalance and pre-existing harmonic voltages.

Abstract: An apparatus provides multiple, phase-shifted power outputs, such as for driving a rectifier circuit of an electronic frequency converter. The apparatus connects to a multi-phase power source having a predetermined number of phases, such as a conventional three-phase alternating current source provided by a public utility. The apparatus causes a first phase shift in response to current flow from the power source through the input of the apparatus. The apparatus also includes an output. The output is responsive to current flow through the input such that the apparatus causes a second phase shift and provides multiple power outputs of different phases in response to the first and second phase shifts. The output of the apparatus includes at least two closed circuit winding groups.

Abstract: A 18-pulse converter system operates without interphase transformer and neutral point on the DC side by providing three rectifier bridges across the DC terminals, one rectifier bridge being coupled with the AC terminals and the two other rectifier bridges being operated at + and -40 degress phase shift, while the rectifier devices are controlled for 40-degree current conduction.

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: A polyphase transformer design is presented in which transformer output pors are accurately constructed in both voltage magnitude and relative phase angle. The design incorporates both main and auxiliary transformers that are used in unison to produce the accurately constructed phasors. The main transformer permits rough phasor adjustment to be made with the auxiliary transform permitting phasor fine tuning. Such a design is particularly suitable in transformer approaches that require output phases that are of a number not evenly divisible by three.

Abstract: A balanced three phase AC power supply for a computer system having unbalanced, variable DC loads. AC to DC converters utilize high power factor correction circuitry to impose a sinusoidal current loading waveshape substantially in phase with the AC voltage. Each AC to DC converter outputs equal DC voltages maintaining a balanced loading on the AC power source. The design and organization of the power supply components make the supply fault tolerant when one phase of AC power or one AC to DC converter is lost due to malfunction or servicing.

Abstract: A high voltage power supply for an x-ray tube operating from a single phase alternating current source and including a phase shifter and/or solid state switch for providing first and second phase signals. Each of these signals or one of them are half-wave rectified. An output combining circuit provides for transformation to a high voltage while at the same time providing for additive combination of the signals from the half-wave rectifiers.

Abstract: A multiphase transformer is provided for converting an input signal having N phases into an output signal having M phases. The transformer includes a plurality of first windings connected together to provide a load for an N phase signal, with each of the first windings having a plurality of take-off points, including tap-off points interior to the ends of the first windings. A mechanism is provided for coupling the input signal to the first windings. A plurality of M output terminals is further provided as is a mechanism for coupling the M output terminals to at least some of the take-off points of the first windings. This mechanism includes a plurality of second windings, with the second windings each electrically coupled between one of the output terminals and one of the tap-off points of the first windings and with each of the second windings magnetically coupled to another of the first windings.