MXPA96002800A - Asynchronous traction tension and chain reducing device powered under single-phase network that has such dispos - Google Patents

Abstract

The present invention relates to a voltage reducing device, which has at least one pair of single-phase rectifiers (1, 2, 1, 6) in forced commutation, which operate on the secondary windings (3, 4 or 3, 5) of a main transformer T of traction, the emitted power of a continuous network that transits through the main transformer T traction, being the energy recovered on a secondary winding (5) by means of a single-phase rectifier (6) in forced commutation, working as rectifier controlled elevator of voltage, the other single-phase rectifiers (1, 2) in forced switching operate synchronously as a voltage inverter. The present invention also relates to an asynchronous traction chain fed under a single-phase network, which has a voltage reducing device such as that described above.

Description

DEVICE FOR REDUCING TENSION AND ASYNCHRONOUS TRACTION CHAIN SUPPLIED UNDER SINGLE PHASE NETWORK SUCH DEVICE FIELD OF THE INVENTION The present invention relates to asynchronous traction chains fed under single-phase networks, in general, and relates, more particularly, to a voltage reducing device as well as to an asynchronous traction chain fed under a single-phase network, which has such a device.

BACKGROUND OF THE INVENTION According to the known state of the art, the asynchronous traction chains fed under a single-phase network essentially use voltage inverters or drivers that guide the traction motors and single-phase rectifiers in forced switching that distribute an intermediate direct voltage, which serves from voltage source to the inverters. These prior art traction chains allow to standardize the arms of the corrugators or vibrators, as well as the arms of the REF: 22799 rectifiers that are not adjusted to size more than to support the continuous intermediate tension. In certain applications, the traction chains must operate under more supply networks at the same time continuous and alternate, for example under 3000 V supply voltage and in direct current. In such applications, the inverters and rectifiers can not be connected directly to the high DC voltage. A known solution consists in reconfiguring the arms of the rectifiers, so as to obtain a parallel series scratching with the objective of reconstituting, under 3000 V power supply, the same intermediate DC voltage that feeds the traction corrugators under single-phase power. One of the means to put this solution into operation is the use of electromechanical means that allow to switch the power scheme as well as the use of smoothing inductances. It is sometimes possible to replace the inductances with the secondary windings of the single-phase traction transformer. One drawback of these known solutions is the reconstitution of several intermediate tensions. In effect, these intermediate tensions are not all referred to the same potential. By way of example, one of the intermediate voltages is directly connected to the positive terminal of the supply voltage. A direct consequence is that the set of equipment below this intermediate voltage, must be known to withstand an electrical insulation, for example 3000 V, relative to the mass, or, according to the CEI standard, efficiencies of 9500 V, at 50 Hz. This dielectric dimensioning voltage is introduced to oversize the insulators, the running distances but also to increase the thermal resistance of the cooling systems of the semiconductors. In this way, an object of the invention is a voltage reducing device used in an asynchronous traction chain, fed under a single-phase network that does not have the aforementioned drawbacks. The fundamental idea of the voltage reducing device of the invention is not to reconstitute more than a single intermediate continuous voltage. The value of the intermediate DC voltage is equal to approximately half of the input voltage.

- - The intermediate DC voltage is galvanically isolated or not in the supply network. According to the invention, the voltage reducing device is characterized by at least one pair of single-phase rectifiers in forced switching operating on the secondary windings of a main traction transformer, the power emitted from a continuous network that transits through the transformer main traction, being the energy recovered on a secondary winding by means of a single-phase rectifier in forced commutation, which works as a voltage-controlled rectifier, the other single-phase rectifiers in forced commutation operate synchronously in a voltage inverter, the winding being primary of the main transformer T, in open circuit.

BRIEF DESCRIPTION OF THE INVENTION The voltage reducing device of the invention satisfies according to a first preferred embodiment one or more of the following characteristics: a first and a second one-phase rectifiers in forced commutation that feed, respectively, a first and a second secondary windings of a transformer The first and second single-phase rectifiers work synchronously in the full-wave voltage inverter and feed, respectively, the first and second secondary windings of the main traction transformer, and a third single-phase rectifier in forced switching works as voltage-controlled rectifier, and is powered by the third secondary winding of the main traction transformer, - the first, second and third secondary windings of the main traction transformer have the same number of turns. The voltage reducing device of the invention satisfies, according to a preferred embodiment, the characteristic according to which the first and second single-phase rectifiers in forced switching of each of the pairs, are mounted in series, each of the pairs being powered under an input voltage, the first single-phase rectifiers operate synchronously in a voltage inverter and feed the first secondary winding of the main transformer of traction, with which it is associated, and the second single-phase rectifiers in forced commutation operate as rectifier-controlled - , voltage booster, and are fed by the second secondary winding of the main traction transformer, which is associated with it. The voltage reducing device of the invention satisfies, according to any of the preferred embodiments, at least one of the following characteristics: the feeding of the first and second secondary windings of the main transformer 0 of traction, is effected by means of a alternating frequency square voltage, such that the magnetic circuit of the main transformer T is not saturated, the single-phase rectifiers work as recurs controlled elevators of 5 tension, which regulate their direct output voltage to a value a little more than half of the value of the input voltage. Finally, according to another feature, the present invention relates to a traction or asynchronous chain fed under a single-phase network, which has a voltage reducing device as described above. An advantage of the voltage reducing device of the invention is that of not resorting to parallel series scratches.

DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the invention will appear on reading the description of the preferred embodiment of the voltage reducing device, description made in conjunction with the drawings in which: Figure 1 represents a preferred embodiment of the voltage reducing device, with galvanic isolation according to the invention, Figure 2 represents a preferred embodiment of the voltage reducing device, without galvanic isolation according to the invention, Figure 3 represents an extension of the voltage reducing device shown in Figure 2, to a voltage reducing device having six single-phase rectifiers.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 represents a preferred embodiment of the voltage reducing device, with - - Galvanic isolation according to the invention. A first 1 and a second 2 single-phase forced-circuit rectifiers are fed in series under an input voltage E, for example 3000 V 'The first 1 and the second 2 single-phase rectifiers feed, respectively, a first 3 and a second 4 secondary windings of a main transformer T traction. The first and second single-phase rectifiers operate synchronously as an inverter or voltage vibrator. The first and second single-phase rectifiers feed the first and second secondary windings 3, 4 of the main traction transformer, for example, by means of an alternating square voltage, for example, of 3000 V / 2, at a frequency such that the magnetic circuit of the main traction transformer T is not saturated. A third single-phase rectifier 6 in forced switching is fed by the third secondary winding 5 of the main traction transformer T. This third single-phase rectifier 6 functions as a voltage-controlled rectifier according to the same principle as under the single-phase network, and thus regulates its output voltage S to a value a little higher than 3000 V / 2. The main transformer T has a primary winding 7 in open circuit, the primary winding is therefore unusable. In the foregoing, it has been hypothesized that the three sedimentary windings of the main traction transformer have the same number of turns, which is the case, for example, in the field of railway traction. The intermediate DC voltage is galvanically isolated and can be referred to the mass M as a low single phase network. A pilot device (not shown) integrated into the control electronics of the first and second single-phase rectifiers has the function, on the one hand, to balance the voltages between these single-phase rectifiers and, on the other hand, to ensure the absence of direct current in the first and the second secondary windings. This device, integrated into the control electronics of the first and second single-phase rectifiers, is capable of rectifying the variations or discrepancies by acting on the cyclic conduction efficiency of the semiconductors of the first and / or the second single-phase rectifier. The voltage reducing device of the invention, which has a primary winding of the main transformer in open circuit, has the advantage of: reconstituting a single continuous output voltage that can always be referred to the mass, - reconstituting a single voltage with galvanic isolation or without galvanic isolation, - avoid the insulation to the input voltage of the equipment fed by the direct voltage and avoid the use of supplementary inductance smoothing, as is the case in the devices of the prior art. Figure 2 represents a preferred embodiment of the voltage reducing device, without galvanic isolation according to the invention. A first 1 and a second 6 single-phase rectifiers in forced switching, are fed in series under an input voltage E, for example of 3000 V. The first single-phase rectifier 1 in forced switching, has the same function as the first single-phase rectifier described above , in relation to Figure 1. The first single-phase rectifier 1 feeds a first secondary winding 3 of a main traction transformer T. As a reminder, the first single-phase rectifier 1 operates on an oscillator and distributes an alternating square voltage, for example of 3000 V / 2, to the first secondary winding 3 of the main traction transformer. The second single phase rectifier 6 in forced commutation is fed by a second secondary winding 5 of the main transformer T of tension. This second single-phase rectifier 6 operates on a voltage-controlled controlled rectifier according to the same principle as under the single-phase network, and regulates an output voltage S referred to the mass M of a value, for example, a little higher than 3000 V / 2. . The main transformer T has a primary winding 7 in open circuit, the winding is therefore unusable. The pilot device (not shown) of the first single-phase rectifier 1 has the sole function of ensuring the absence of direct current in the first secondary winding.

- - The control device (not shown) of the second single-phase rectifier 6 has the function of regulating the output voltage S. FIG. 3 shows an extension of the voltage reducing device shown in FIG. 2, to a voltage reducing device having six rectifiers monophasic In this Figure 3 there are three pairs of single-phase rectifiers 1, 6 in forced switching, each of the pairs of single-phase rectifiers is fed under an input voltage 3, for example of 3000 V. Each of the first single-phase rectifiers 1 is associated with a first secondary winding 3, and each of the second single-phase rectifiers 6 is associated with a second secondary winding 5. The first single-phase rectifiers 1 each feed a first secondary winding 3, of the same main transformer T of traction. The second single-phase rectifiers 6 all operate in voltage-controlled controlled rectifier, and all regulate the same output voltage S referred to the mass M of a value, for example, a little higher than 3000 V / 2.

The main transformer T has a primary winding 7 in open circuit, the primary winding is therefore unusable. It follows, from one or another of the preferred embodiments described above, that the voltage reducing device of the invention possesses at least one pair of single-phase rectifiers 1, 2 or 1, 6 in forced commutation, operating on the secondary windings. 3, 4 or 3, 5 of a main transformer T, the emitted power of a continuous network transits through the main transformer T, the energy recovered on a secondary winding 5 by means of a single-phase rectifier 6, in Forced switching, which works as a voltage-controlled rectifier, the other single-phase rectifiers 1, 2 in forced switching operate synchronously in voltage inverters. The voltage reducing device of the invention finds particular application, but not exclusively, in the field of railway traction. In this way, the present invention relates to an asynchronous traction chain fed under a single-phase network, which has a voltage reducing device as described above.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates.

Having described the invention as above, the contents of the following are claimed as property:

Claims (8)

1. A voltage reducing device, characterized in that it has the means that do not reconstitute more than a single intermediate continuous voltage.

2. The device according to claim 1, characterized in that the means that have at least one pair of single-phase rectifiers in forced switching, operate on the secondary windings of a main traction transformer, the power produced of a continuous network that transits through the traction main transformer, with the energy recovered on a secondary winding by means of a single-phase rectifier in forced commutation, which works in voltage controlled rectifier rectifier, the other single-phase reducers in forced commutation work synchronously as a voltage inverter, the primary winding of the main transformer in open circuit.

3. The device according to any of claims 1 and 2, characterized in that a first and a second single-phase rectifiers in forced switching feed, respectively, a first and a second secondary windings of a main traction transformer, the first and second single-phase rectifiers they work synchronously as a voltage inverter and feed, respectively, the first and second secondary windings of the main traction transformer, and a third single-phase rectifier in forced switching works as a voltage-controlled controlled rectifier and is powered by the secondary winding of the secondary winding. main traction transformer.

4. The device according to any of claims 1 to 3, characterized in that the first, second and third secondary windings of the main traction transformer have the same number of turns.

5. The device according to any of claims 1 and 2, characterized in that the first and second single-phase rectifiers in forced switching of each of the pairs, is mounted in series, each of the pairs is powered under an input voltage, the first single-phase rectifiers work synchronously in the voltage inverter, and feed the first secondary winding - of the main traction transformer that is associated with it, and the second single phase rectifiers in forced commutation operate as rectifier controlled voltage riser, and are fed by the second secondary winding of the main traction transformer that is associated to it.

6. The device according to any of claims 1 to 3 or 5, characterized in that the supply of the first and second secondary windings of the main traction transformer, is carried out by means of an alternating square frequency voltage, such that the magnetic circuit of the main traction transformer is not saturated.

7. The device according to any one of claims 1 to 3 or 5, characterized in that the single-phase rectifiers work as controlled rectifiers, which regulate their continuous output voltage to a value a little more than half the value of the voltage of entry.

8. The asynchronous traction chain, characterized in that it is fed under a single phase network that has a voltage reducing device according to any of claims 1 to 7.