Abstract: An uninterruptible power supply system includes a plurality of uninterruptible power supply devices (U1 to U3) connected in parallel between a commercial AC power supply (70) and a load (71); and a control unit (5) selecting the required number of uninterruptible power supply devices for driving the load (71) from the plurality of uninterruptible power supply devices (U1 to U3), to cause each selected uninterruptible power supply device to be operated and to cause each remaining uninterruptible power supply device to be stopped. This control unit (5) changes the uninterruptible power supply devices to be operated from one to another in a predetermined cycle such that the plurality of uninterruptible power supply devices (U1 to U3) are identical in operation time to one another. Accordingly, the continuous operation time of each of the uninterruptible power supply devices can be shortened, so that failures occurring in each uninterruptible power supply device can be reduced.

Abstract: An inverter apparatus converts a DC power of a capacitor charged via a rectifier circuit connected to a first AC power system into an AC power, and supplies the AC power to a second AC power system. The inverter apparatus includes a discharge circuit, a control circuit, a trigger circuit, a first voltage-sag detection circuit, a control power circuit, and a second voltage-sag detection circuit. When the second voltage-sag detection circuit detects a voltage sag of the control power circuit below a threshold, the trigger circuit generates a discharge command signal for causing the discharge circuit to discharge a charge from the capacitor.

Abstract: Power conversion systems with active front end converters for example motor drives and power generation systems for distributed energy sources are presented with adaptive harmonic minimization for grid-tie converters for minimized or reduced total harmonic distortion in the line current spectrum including the source harmonic current and the grid-tie converter injected current spectrum referred to the line side.

Abstract: A method of controlling an uninterruptible power supply apparatus (UPS) is provided. The UPS apparatus includes at least an AC input voltage, a DC input voltage and a single-phase AC/AC converter. The single-phase AC/AC converter includes an AC inductor, a bus capacitor, a boost arm, a common arm and a buck arm. The method includes steps of: controlling the bus voltage to have a DC component and full-wave rectifying component, and setting a bus voltage parameter K so that the bus voltage approaches to a full-wave rectifying voltage when K approaches to 1, wherein 0?K?1.

Abstract: A control device for a vehicle, the control device including, in a housing that is installed under a floor of the vehicle: a power converter configured of a semiconductor switching circuit; a control unit that controls the output of the power converter so as to supply a required load to a power; a wiring that is connected to the power converter; a voltage detector that detects a voltage applied to the wiring and outputs the detected voltage to the control unit; and a shielding unit that shields radiation noise from the wiring to the voltage detector, wherein the control unit is disposed on a first side of the housing along a traveling direction of the vehicle, the power converter is disposed on a second side of the housing along the traveling direction of the vehicle and the voltage detector is disposed between the power converter and the control unit.

Abstract: The present invention relates to a circuit minimizing standby power in a power adapter with a power-frequency transformer (T1), which includes a sensing circuitry (1), a driving circuitry (2), a switching circuitry (3) and a resistive element (Z). When the sensing circuitry (1) senses a power supply signal of the power-frequency transformer (T1) in work mode, the switching circuitry (3) shorts the resistive element (Z); and when the power-frequency transformer (T1) is in standby mode, the electronic switch (3) is switched off and the resistive element (Z) is coupled to the power-frequency transformer (T1). The circuit attached to the power adapter reduces the standby power consumption very much, and achieves energy-saving effect with low cost.

Abstract: Methods and apparatus are provided for operation of a voltage source inverter. A method of operating a voltage source inverter having an output with multiple voltage phases having a DC voltage level, the method comprising sensing a low output frequency condition; determining a DC voltage offset responsive to the low output frequency condition; and applying the DC voltage offset when operating the voltage source inverter resulting in a change to the DC voltage level of the multiple voltage phases.

Abstract: The performance of a power transducer is improved while efficiently using a power semiconductor also by managing the permissible duty factor of the power semiconductor in the regenerative braking circuit provided in the power transducer. The user is allowed to set, through an operation panel provided on the power transducer, the resistance value of the regenerative braking resistor for thermally consuming the rotational energy generated during motor deceleration. The power transducer performs the steps of: calculating the current which flows in the regenerative braking circuit from the resistance value setting; obtaining the generation loss of the power semiconductor in the regenerative braking circuit with the calculated current value; and determining the permissible duty factor of the power semiconductor from the obtained generation loss.

Abstract: A motor drive circuit has a converter for coupling to an AC voltage source and an inverter coupled to the converter for providing a drive current for a motor. A common mode circulation loop is coupled to the converter and to the inverter, and circulates common mode current from both the converter and the inverter.

Abstract: A circuit 1 for controlling the supply of electrical power to an induction coil 2, in particular to an induction coil 2 for heating a shrink attachment for tools, comprises a rectifier 3, having an input 3a, 3b, 3c for feeding an input power, and a rectifier output. The circuit 1 furthermore comprises an inverter 5 for putting out an AC-voltage, having an input and an inverter output 5a, 5b for connecting the induction coil 2, an intermediary circuit 4 for connecting the rectifier 3 with the inverter 5, and a regulation unit for regulating the power supplied to the induction coil 2. A measurement apparatus 6 for measuring a voltage A2 as an input variable for the regulation unit is connected to the output side of the inverter 5. A respective method for regulating the power supplied to the induction coil 2 comprises a regulation step, in which the current A2 supplied to the induction coil 2 is used as an input variable for the regulation of the power supplied to the induction coil 2.

Abstract: In an inverter generator, having a generator unit driven by an internal combustion engine whose throttle valve is moved by an actuator and generates alternating current, and an inverter that converts converted direct current to alternating current with switching elements to supply to an electrical load, voltage and current supplied to the electrical load is detected, a power factor is calculated from the detected voltage and the current, a power of the load is estimated from the detected current and the calculated power factor. Then a desired speed of the engine is determined based on the estimated power of the load, and the actuator is controlled such that an engine speed becomes equal to the desired engine speed, thereby improving the response of engine speed control.

Abstract: The present invention relates to electricity generating equipment, particularly off-shore generators for generating electricity from tidal streams, marine currents or wave motion. In a generator (101) according to one embodiment, each three-phase set (113) of three coils (109) is connected to a separate rectifier (121), the output of which is subsequently inverted to produce a substantially constant-voltage, constant-frequency AC output, for onward transmission and/or direct connection with the outputs of other similar generators (101), or the grid.

Abstract: The invention discloses a method and system to detect zero current conditions in a buck inductor by monitoring the voltage across the buck inductor. Once zero current and voltage conditions are present, an inverter circuit changes the operational state, i.e. conducting or non-conducting, of the switching transistors driving the lamps to reduce power loss associated with changing the operational state of switching transistors when under a load.

Abstract: This invention relates to a kind of LLC resonant converter for full input voltage range and its control method, and belongs to LLC resonant power conversion field. The technical solution: the current type main tank current sampler test the main tank current signal of the LLC resonant conversion circuit, and its output signal passes a rectifier then to be sent into the main tank energy quantifier connected to it. In the bus voltage range from 5% Vmax to Vmax, the main tank energy quantifier can count the remained LLC resonant main tank energy corresponding to measuring the bus transient voltage, and output a stable energy wave Vo, and if the remained LLC resonant energy falls down to a given energy value, the energy comparator output control signal and the controller controls the electronic switch device turning off, and the corresponding electronic switch gains a ZVS in the next half working period of LLC resonant converter.

Abstract: An apparatus for generating a compensation signal for a power converter where the second harmonic ripple on the voltage bus is substantially removed from the compensation signal. The apparatus comprises a frequency-locked clock generator, a bus voltage data generator, a stack, and a compensation signal generator. The frequency-locked clock is coupled to the power converter voltage bus that contains harmonics of the AC line frequency. The clock generator frequency locks to the second harmonic of the AC line frequency and creates a system clock which is used for the synchronous operations throughout the apparatus. The bus-voltage data generator inputs a power converter scaled-bus voltage, generates bus-voltage data at a sampling rate which is determined by the coupled system clock. The output of the bus-voltage generator is input into a stack.

Abstract: A phase-controlled power supply is disclosed. The power supply includes a power conditioner with an input configured to connect to an external source of electrical power, the power conditioner being configured to provide conditioned power on its output. The power supply also includes a transformer having a primary winding and a secondary winding, and a switching module coupled between the output of the power conditioner and to the primary winding of the transformer. The switching module has two modes of operation and a control signal input configured to accept a first control signal. The switching module includes a switching element configured to connect the power conditioner output to the primary winding of the transformer. The switching module operates in the first mode when the first control signal is in a first state, switching the first switching element at a first frequency and first duty cycle.

Abstract: An inverter controller comprising an AC motor as a load. A rectifying circuit converts AC power from an AC power source into DC power. A smoothing capacitor smoothens a DC voltage from the rectifying circuit. An inverter circuit converts DC power supplied via the smoothing capacitor into a desired frequency. A current detection circuit detects a output current of the inverter circuit. A voltage detection circuit detects a terminal voltage (Vpn) of the smoothing capacitor. A voltage command calculation circuit calculates a voltage command to the AC motor. A speed command calculation circuit calculates a speed command to be used when it is determined that the AC power source is in a power failure state or when the terminal voltage (Vpn) reaches a certain value.

Abstract: An uninterruptible power supply apparatus includes a cooler cooling a converter/chopper circuit and a cooler cooling a PWM inverter. The converter/chopper circuit and the cooler make up one integrated unit. Accordingly, a smaller apparatus can be achieved, compared with a conventional apparatus in which a cooler is provided for each of a converter and a chopper.

Abstract: Primary and secondary coils are provided in the first through section and a coil group is also provided in the second through section. Hence, the surface area over which the coil group extends within a plane which is perpendicular to the through sections is greater than in the case where all of the coils are provided in a single through section. The surface area which is not covered by the magnetic body cores of the platelike members increases. In cases where the surface area of the members is large, the heat radiation characteristic is enhanced. Hence, the cooling efficiency of the transformer improves. In cases where there is a plurality of coil groups which are magnetically coupled to one another in particular, because it is difficult to move the heat produced in the plurality of coil groups through heat conduction, heat transfer, or heat radiation, a heat radiation structure of this kind is effective.

Abstract: A DC/AC converter incorporates at least one Magistor module having a first sp control switch, a second sz control switch and a third sm control switch. An AC source is connected to an input of the at least one Magistor module. A switch controller connected to the first sp control switch, second sz control switch and third sm control switch to and provides pulse width modulation (PWM) activation of the switches for controlled voltage at an output.

Abstract: A soft-start circuit includes a power source, a switch, a capacitor and a regeneration brake circuit. The regeneration brake circuit absorbs a return current. The regeneration brake circuit includes a resistor, a diode and a transistor. The resistor is connected between two poles of the power source via the transistor. The diode is connected between the resistor and the positive pole of the power source via the switch. The capacitor is connected between the negative pole of the diode and the transistor. The switch is connected between the negative pole of the diode and resistor. When the switch turns off, the power charges the capacitor via the resistor and the diode of the regeneration brake circuit. When the switch turns on, the return current turns the transistor on, and the resistor absorbs the return current.

Abstract: A detected DC voltage value estimation mechanism samples detected DC voltage values at specific intervals of a period T, stores detected DC voltage values Vn to Vn?m detected at a present time tn up to a sampling time tn?m which is m sampling cycles (m?1) before the present time tn, and calculates a DC voltage estimation value Vn+1 at a next time tn+1 using the detected DC voltage values Vn to Vn?m, expressing a curve connecting the voltage values Vn to Vn?m by a specific function. An output voltage control into which the DC voltage estimation value Vn+1 is input corrects an output voltage command value and outputs the corrected output voltage command value to a power converter.

Abstract: A hybrid vehicle includes: first and second rotary electric machines; a matrix converter connecting the first and second rotary electric machines to each other to provide AC to AC power conversion between both the rotary electric machines; a battery connected to an electrical path branched off between the matrix converter and the second rotary electric motor; an inverter interposed among the battery, the matrix converter and the second rotary electric machine to convert AC power to DC power and vice versa; and a controller. The controller activates the first rotary electric machine with power fed from the battery and restrains the change in torque output of the second rotary electric machine at the activation of the first rotary electric machine.

Abstract: Methods and apparatus for simulating resistive loads, and facilitating series, parallel, and/or series-parallel connections of multiple loads to draw operating power. Current-to-voltage characteristics of loads are altered in a predetermined manner so as to facilitate a predictable and/or desirable behavior of multiple loads drawing power from a power source. Exemplary loads include LED-based light sources and LED-based lighting units. Altered current-to-voltage characteristics may cause a load to appear as a substantially linear or resistive element to the power source, at least over some operating range. In connections of multiple such loads, the voltage across each load is relatively more predictable. In one example, a series connection of multiple loads with altered current-to-voltage characteristics may be operated from a line voltage without requiring a transformer.

Abstract: Sensor for measuring electrical parameters in a high voltage environment comprising a high voltage side (4) for connection to high voltage conductors, a low voltage side (6) for connection to low voltage power supply and measurement signal control circuitry, a measurement signal circuit (16), and a power supply circuit (14), and at least one isolating transformer (18, 20) for transmission of electrical power supply and/or measurement signals between the low voltage side and the high voltage side. The isolating transformer comprises at least a first and a second transformer core (28), a transformer coil (33) on a circuit board around a branch (27) of the transformer core on the high voltage side and a transformer coil (32) on a circuit board around a branch (29) of the transformer core on the low voltage side, the isolating transformer further comprising an intermediate coil (36) encircling at least one branch of each said at least two transformer cores.

Abstract: Systems and methods for operating a variable speed drive to receive an input AC power at a fixed AC input voltage and frequency and provide an output AC power at a variable voltage and variable frequency. The variable speed drive includes a converter stage to convert the input AC voltage to a boosted DC voltage, a DC link connected to the converter stage to filter and store the boosted DC voltage from the converter stage; and an inverter stage to convert the boosted DC voltage into AC power with variable voltage and the variable frequency. An integral bypass contactor is connected in parallel with the VSD between the AC power source and the AC output power. The integral bypass contactor is arranged to bypass the VSD when the VSD output frequency and voltage are approximately equal with the AC input voltage and frequency.

Abstract: A drive system for operation of a tap changer for voltage regulation of a transformer on load. An electric motor is connectible to a movable part of the tap changer for moving the movable part for carrying out a tap change operation. An electric converter connects an electric power supply to the electric motor. A control arrangement is adapted to control the electric converter for controlling the operation of the motor and by that of the tap changer.

Abstract: A static exciter system (20) for the field winding (17) of a generator (16) which is connected to a grid system via a busbar (19) includes a first device (12, 18, 21) for production of a DC voltage, which is connected to the field winding (17) and together with the field winding (17) form an exciter circuit, as well as a second device (23; 29, C1, . . . , C3) for emission of electrical energy, which second device (23; 29, C1, . . . , C3) briefly feeds additional energy into the exciter circuit when required. An exciter system such as this results in the capability to briefly increase the excitation in a simple, functionally reliable and space-saving manner, by inserting a forward-biased diode (22) into the exciter circuit, and by the capability to connect the second device (23) to the diode (22), in the reverse-bias direction, in order to feed the energy into the exciter circuit.

Abstract: An architecture for a power supply with an integrated UPS control system to which generic batteries may be connected. Such an architecture greatly reduces the overall cost, complexity, size and inefficiency of providing uninterruptible power to a device such as a computer system.

Abstract: A power converter is provided with a rectifying circuit, an inverter circuit, and a common mode filter including a common mode choke coil and a capacitor. The switching frequency of a PWM rectifying circuit is set at three times the switching frequency of a PWM inverter. Alternatively, the resonance frequency of the common mode filter is set at twice the carrier frequency of the rectifying circuit or the PWM inverter circuit or more.

Abstract: Power conversion systems and methods are presented for damping common mode resonance, in which inverter or rectifier switching control signals are selectively modified according to a damping resistance current value computed using a predetermined virtual damping resistance value in parallel with an output or input capacitor and a measured output or input voltage value to mitigate or reduce common mode resonance in the converter.

Abstract: A voltage control rate of an inverter has a DC component and an AC component. This AC component has a frequency which is six times a fundamental frequency of an AC voltage outputted by the inverter. Even when there are not only a fifth-order harmonic component but also a seventh-order harmonic component of a load current, a ratio between the magnitude of the AC component and the DC component can be appropriately set.

Abstract: The invention relates to a method for reducing the idle current requirement of a base frequency clocked supply side converter (1) on idle and with low motor loads, provided with controllable semiconductors (T1,T2,T3,T4, T5,T6), wherein the base frequency clocking of the semiconductor switches (T1,T2,T3,T4,T5,T6) occurs depending on the desired direction of flow of power. A converter (1) for carrying out said method is also disclosed.

Abstract: Provided is a power converter having an inverter (13) wherein capacitors (12) are connected in parallel on a direct current side, and a power supply circuit configured to supply the inverter with a direct current from a power supply (1) and a power storage element (14). A controller using such power converter is also provided for electric rolling stocks. The power supply circuit is provided with a power supply switch (S1) arranged between the power supply and the inverter, a DC-to-DC converter (15A) arranged between the power storage element and the inverter, and a bypass switch (S2) arranged between the power storage element and the inverter.

Abstract: Provided is an AC/AC conversion power supply device including: n(n?2) rectification circuits (D1 to Dn) connected in series with respect to an AC input; n high-frequency switching circuits (SC1 to SCn) respectively connected to outputs of the rectification circuits (D1 to Dn); and n transformers (TR1 to TRn) each having a primary winding connected to the outputs of high-frequency switching circuits (SC1 to SCn). The transformers (TR1 to TRn) have secondary windings connected in parallel to one another through the rectification circuits (D1 to Dn) and an output switching circuit (SW) for converting the outputs into AC current. The high-frequency switching circuits (SC1 to SCn) include delay circuits (C14, R14; C24, R24) which can delay a waveform of the high-frequency switching signal.

Abstract: Systems and methods for improved VSDs are provided. One embodiment relates to an apparatus for common mode and differential mode filtering for motor or compressor bearing protection when operating with VSDs, including conducted EMI/RFI input power mains mitigation. Another embodiment relates to a method to extend the synchronous operation of an Active Converter to the AC mains voltage during complete line dropout. Another embodiment relates to an Active Converter-based Variable Speed Drive system with Improved Full Speed Efficiency.

Abstract: A resonance power generator is provided. The resonance power generator includes an alternating current/direct current (AC/DC) rectifier to rectify an input signal of an alternating voltage and an AC generator to generate an AC signal based on the rectified signal that is output from the AC/DC rectifier. The resonance power generator may also include, for example, a control unit to control a frequency of the AC signal, a filter unit to remove a spurious signal or a harmonic element included in the AC signal, a voltage/current amplifier to amplify the AC signal, and a source resonator to transmit a power to a target resonator.

Abstract: A semiconductor module has switching semiconductor elements connected in parallel to each other and at least a free wheeling semiconductor element reversely connected in parallel to the switching semiconductor elements. The free wheeling semiconductor element is placed between the switching semiconductor elements. At both end parts of the semiconductor elements, each of the switching semiconductor elements is placed. A longitudinal side of each of the switching semiconductor elements and the free wheeling semiconductor element is placed in parallel to a short side of the semiconductor module. An electric-power conversion device has a plurality of arms. Each arm is composed of the semiconductor elements.

Abstract: The present invention provides a power device including a converter part (2) for converting an AC voltage to a DC voltage; an inverter part (3) for converting the DC voltage outputted from the converter part (2) to the AC voltage; and a transformer (4) having an inductance forming a series resonance circuit together with an electrostatic capacity of a load (20) to boost the AC voltage outputted from the inverter part (3). In the power device, an inductance (7) is connected to the output part of the inverter part (3) in parallel with the transformer (4). Thus, in a discharge part 6 provided in the load (20), since when a discharge is not generated, a recovery current is not supplied to a circulating current diode in the inverter part (3), or the quantity of the recovery current is reduced, the heat generation of the circulating current diode can be suppressed without increasing the number of elements of the circulating current diode.

Abstract: A rotating electrical machine control device includes an inverter; a resolver; a unit; a three-phase/two-phase modulation switching unit; and a motor control unit that switches to a two-phase modulation in a specific region where an electric noise given to the resolver by a rotating electrical machine is large, even in a region where the modulation ratio is smaller than the three-phase/two-phase modulation switching boundary.

Abstract: Embodiments of the invention relate to a method and apparatus for a zero voltage processor sleep state. A voltage regulator may be coupled to a processor to provide an operating voltage to the processor. During a transition to a zero voltage power management state for the processor, the operational voltage applied to the processor by the voltage regulator may be reduced to approximately zero while an external voltage is continuously applied to a portion of the processor to save state variables of the processor during the zero voltage management power state.

Abstract: A power supply apparatus includes first and second parallel-connected uninterruptible power supplies (UPSs), each including an AC/DC converter circuit and a DC/AC converter circuit having an input coupled to an output of the AC/DC converter circuit by a DC link, inputs of the AC/DC converter circuits of the first and second UPSs connected in common to an AC source and outputs of the DC/AC converter circuits of the first and second UPSs connected in common to a load. The first and second UPSs are configured to support a test mode wherein the first UPS is test loaded by transferring power from the output of the DC/AC converter circuit of the first UPS to the output of the DC/AC converter circuit of the second UPS. The first UPS may be configured to provide power to the load concurrent with test loading by the second UPS.

Abstract: A converter section converts a three-phase ac input voltage into a dc voltage, and an inverter section converts the dc voltage converted by the converter section into a prescribed three-phase ac output voltage. The converter section converts the three-phase ac input voltage into the dc voltage on the basis of trapezoidal waveform voltage instruction signals from a trapezoidal waveform voltage instruction signal generating part and a carrier signal from a carrier signal generating part. The inverter section converts the dc voltage converted by the converter section 1 into a prescribed three-phase ac output voltage on the basis of an inverter section instruction signal corrected by an instruction signal correcting part. The trapezoidal waveform voltage instruction signal generating part generates sloped regions of the trapezoidal waveform voltage instruction signals by using a prescribed table.

Abstract: System and method for providing isolated power to a component that is also subject a set of RF signals that includes at least a first RF signal having a first RF frequency is provided. There is included providing a DC voltage signal and modulating the DC voltage signal into an isolated power signal using an isolation transformer. The isolated power signal has an intermediate frequency that is higher than 60 Hz and lower than the first RF frequency. There is included supplying the DC voltage signal to the primary winding and obtaining the isolated power signal from the secondary winding; and delivering the isolated power to the component using the isolated power signal.

Abstract: A voltage sag generator device for use in an electrical generator machine such as a wind turbine, connected to an electrical network including one to three parallel transformers connected on one side to the wind turbine via a coupling switch and circuit breakers, and earthed on the other side via circuit breakers and a control switch. The device includes mechanisms for causing short-circuits when the coupling switch and the control switch are actuated in such a way that a voltage sag having the required duration and type is generated, and mechanisms for protecting the transformers during voltage sag generation.

Abstract: A vehicular power converter includes switches and first and second inductive components. The first and second inductive components have substantially adjacent portions and are coupled to the plurality of switches such that when current flows from the plurality of switches and through the first and second inductive components, flux generated by the current flowing through the adjacent portions of the first and second inductive components and located between the adjacent portions is oriented in substantially opposite directions.

Abstract: An induction motor drive includes a plurality of inverters, a changeover switch which changes over outputs of the plurality of inverters to be supplied to one induction motor and a changeover controller which controls the changeover switch on the basis of a failure detection signal of one inverter to change over from the one inverter to another inverter to start the other inverter so that the induction motor is driven. The changeover controller includes a frequency/phase detector which always detects a frequency and a phase of a terminal voltage of the induction motor and a starting frequency/phase setting device which controls a frequency and a phase at starting of the other inverter in accordance with detected values of the frequency/phase detector when the failure signal is inputted.

Abstract: An AC inverter circuit supplies power to multiple lamps in an LCD backlight. Conventional AC power is used as direct input into a full wave rectifier that converts the input from AC to a DC reference voltage. A transformer driver, including a chopper, converts the DC reference voltage to a higher voltage AC which drives a step up transformer to produce a voltage sufficient to drive as many as six fluorescent lamps. The components/circuitry associated with the transformer's primary windings is optically isolated from the rest of the circuit.

Abstract: A variable frequency drive comprises a diode rectifier receiving multiphase AC power from a source and converting the AC power to DC power. An inverter receives DC power and converts the DC power to AC power to drive a load. A link circuit is connected between the diode rectifier and the inverter and comprises a DC bus to provide a relatively fixed DC voltage for the inverter. A bus capacitor is across the bus. A soft charge circuit limits inrush current to the bus capacitor. The soft charge circuit comprises an inductor connected between the source and the link circuit and a switch circuit in the link circuit for selectively providing a semiconverter configuration or a full bridge converter configuration to provide two stage charging of the bus capacitor.

Abstract: A device for transmitting electric power between alternating voltage networks includes converters interconnected by direct current lines and provided each with several six-pulse conversion bridges. The six-pulse conversion bridges of one same converter are capable of being connected to an alternating voltage network associated with the converters via inductances differently phase-shifted. A control unit is provided to energize the valves of the six-pulse conversion bridges. The device is more economical and the converters are interconnected by a plurality of direct current circuits, each direct current circuit being galvanically separated from at least an alternating voltage network.