• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Three-phase transformer (10) for a twelve-phase rectifier including two parallel-phase or series-connected two-phase full-wave rectifiers (3,4), comprising: • a main magnetic core (50) having three columns (51,52,53) connected magnetically in parallel at their ends by two yokes (54, 55), and on each of which are wound: • a pair of primary windings (11, 14, 12, 15, 13, 16) connected in parallel, • two secondary windings ( 21-26), three of the secondary windings (21-23) wound on separate columns being connected in delta to the transformer terminals (31-33) connected to a first three-phase full-wave rectifier (3), the other three secondary windings ( 24-26) being star-connected to the transformer terminals (34-36) connected to the second full-wave three-phase rectifier (4), • an auxiliary core (60) having three magnetically connected columns (61, 62, 63). at their ends by two yokes (64,65) closing the field, on each of the columns being wound one of said pairs of primary windings (11,14; 12, 15; 13, 16), characterized in that the auxiliary core (60) comprises a median magnetic portion (69) connecting the midpoints of each column (61, 62, 63) situated between two primary windings of the same pair (11, 14, 12, 15, 13, 16).
    公开号:FR3033930A1
    申请号:FR1552352
    申请日:2015-03-21
    公开日:2016-09-23
    发明作者:Eric Blein；Jean-Noel Fiorina；Alessandro Zoppo
    申请人:Emerson Network Power Industrial System SAS；
    IPC主号:
    专利说明:

    [0001] TECHNICAL FIELD The invention relates to the field of electrical engineering, and more particularly to power rectifiers. BACKGROUND OF THE INVENTION It relates more specifically to a particular transformer structure used to supply twelve-phase rectifiers. It is more particularly a configuration that reduces the harmonic distortion rate current and with the minimum possible losses. BACKGROUND OF THE INVENTION In general, electric power conversion installations are increasingly demanding in terms of performance. Thus, it is generally required that the converters deliver the most constant voltages or currents possible, while generating on the power supply network, or more generally on the power supply source, the lowest possible harmonic disturbances. .
    [0002] Among the most common converters, rectifier systems are known which are powered by a mains network delivering a three-phase voltage, and which generate a DC voltage, for supplying various loads. A conventional configuration consists of using several three-phase full-wave rectifiers, whose outputs are connected in parallel on a common load, and whose inputs are fed by a transformer delivering voltage systems out of phase by an angle depending on the number of connected rectifiers. parallel. A widespread implementation consists in using thyristor rectifiers forming three-phase Graetz bridges, the outputs of which are connected in parallel to a filtering capacitor, and thus the three-phase inputs are connected to two series of outputs. of a three-phase transformer. More specifically, such a transformer comprises three primary windings and two sets of three secondary windings. A first set of secondary windings is star-connected while the second set is delta-connected, so that the voltage systems generated by these two systems are out of phase by 300. In this way, and with a synchronized control of the two rectifiers, the first harmonics of order 5 and 7 generated by each of the rectifiers compensate for the primary ones, so that the input current of the converter has harmonics whose first rank is order 11.
    [0003] In order to filter the output voltage, and to limit the intensity of the input harmonic currents, it is known to use inductances which can advantageously be implemented in series with the primary windings. In this case, the transformer comprises a first main core, on which are wound the primary windings and the secondary windings, on three separate columns, each corresponding to a phase of the supply voltage. The transformer also includes an auxiliary core including three separate columns, each of which is wound only a primary winding.
    [0004] In order to ensure good magnetic coupling between the primary windings and the two sets of secondary windings, each primary winding is generally composed of a pair of two windings connected in parallel, each of these elementary windings being closely wound with the winding. secondary of one of the series. Therefore, the columns of the inductive core or auxiliary core support primary windings, which are traversed by currents out of phase. It follows that the magnetic flux within the column is not homogeneous, and varies between the upper part and the lower part of the same column. The Applicant has thus found that magnetic leak phenomena occur, with a looping of the magnetic field outside the circuit formed by the secondary core, and in particular through the conductors of the primary windings wound on the inductive core. These phenomena increase losses and are therefore detrimental to the efficiency of the transformer. They also increase the harmonic currents in the secondary windings and to a lesser extent in the primary windings. This phenomenon is all the more marked as the power of the converter is high, and more precisely that the intensity of the current flowing in the windings is high. Indeed, to increase the intensity, it is necessary to use strip conductors which have a large section and a small thickness, to be relatively easily deformable and rollable on the columns of the transformer, as opposed to conductors massive flat type. However, the strips have a large width and extend over a larger portion of the column of the inductive core They are therefore subjected more markedly to parasitic fields as mentioned above. A problem to be solved by the invention is that of limiting the current harmonic distortion rate (THDI), while reducing the losses present at the transformer, while maintaining optimum compactness of the converter. DESCRIPTION OF THE INVENTION To this end, the Applicant has designed a three-phase transformer for a 25-phase rectifier including two full-wave three-phase rectifiers connected in series or in parallel according to the application. This transformer includes a main magnetic core which comprises three columns connected magnetically in parallel at their ends by two yokes. On each of these columns is wound a pair of primary windings connected in parallel, corresponding to one phase of the supply network, as well as two secondary windings. Three of these secondary windings, which are wound on separate columns, are star-connected across the transformer which are connected to a first full-wave rectifier. The other three secondary windings are themselves connected in a triangle across the transformer which are connected to the other rectifier. The transformer also has an auxiliary core (or inductive core) which has three columns magnetically connected at their ends by two magnetic field closing yokes. On each of these columns are wound the two windings of one of the pairs of primary windings corresponding to a phase.
    [0005] According to the invention, this transformer is characterized in that the auxiliary core comprises a median magnetic portion connecting the midpoints of each column located between two primary windings of the same pair. In other words, the invention consists in providing the inductive auxiliary core so that the magnetic fields generated by the two half primary windings are closed independently of each other, in additional portions forming an intermediate bridging of the magnetic circuit of the Inductive core In other words, the transformer according to the invention comprises two magnetically autonomous inductive half-cores, and physically assembled in a single frame. In this way, the magnetic leakage is limited, and it is observed that the losses of the transformer are significantly lower than those observed in a configuration where the characteristic middle portion is absent. These advantages are obtained without increasing the overall size of the transformer, since the characteristic bridging portion is located in a separation zone of the two primary half-windings, which must be sufficiently distant to avoid coupling phenomena between secondary windings on the main nucleus. Advantageously in practice, the secondary windings of the same column 30 are wound on one of the primary windings of the same column, to ensure optimal coupling, while avoiding secondary parasitic coupling. The suppression, or at the very least, the very strong limitation of magnetic leakage at the level of the inductive auxiliary core makes it possible to use conductors for the primary and / or secondary windings that can be realized at the same time. from metal strip, thus allowing the use of the transformer with particularly high intensities. Advantageously, in practice, in order to determine the inductance value, it may be provided that the columns of the auxiliary core comprise air gaps, typically made by the separation between different stacked sections to form the columns of the auxiliary inductive core. Brief description of the figures Embodiment of the invention, as well as the advantages thereof, will emerge from the description of the embodiments which follow, in support of the appended figures in which: FIG. 1 is a simplified electrical diagram showing a continuous reciprocating converter including Fig. 2 is a brief perspective view of a transformer according to the invention; Figs. 3 and 4 are brief perspective views respectively of the main core and the auxiliary core of the transformer of the transformer; FIG. 5 is a sectional view along the plane VV 'of FIG. As already mentioned, and as illustrated in FIG. 1, the invention relates to a transformer 10, forming part of a converter 1 providing an AC-DC conversion. More precisely, the transformer 10 is connected as input to a three-phase voltage source 2. At the output, the transformer 10 is connected to two full-wave three-phase rectifiers 3,4 whose outputs are connected in parallel to a filter capacitor 5 for delivering a DC voltage between the output terminals 6,7. More specifically, the transformer 10 comprises six primary windings 11 - 16, connected in pairs 11,14; 12.15; 13, 16, to one of the phases 201, 202, 203 of the three-phase power source 2. Additionally, the transformer 10 also has six secondary windings 21-26 each coupled with one of the primary windings 11-16. The secondary windings 21 - 26 are divided into two series. The first series of secondary windings 21,22,23 is connected in delta to the terminals 31,32,33 of the transformer so as to deliver a system of compound voltages. The second series of secondary windings 24, 25, 26 are connected to the common point 28 in the star configuration, and connected to the terminals 34, 35, 36 of the transformer to which the second rectifier 4 is connected, so as to deliver a system of voltages. simple. Complementarily, from an electrical point of view, the transformer 10 comprises six input inductors 41-46 each connected on the one hand to a primary winding 11-16, and on the other hand to one of the phases 201, 202, 203 of the source. These primary inductances are formed by the primary windings and the magnetic leak generated by the auxiliary inductive core. The primary windings enclosing both the auxiliary core and the main core, the latter being itself surrounded by the secondary windings, it is the insertion of the auxiliary core between primary and secondary which increases and controls the magnetic leak, and therefore constitutes the primary inductance. The invention relates in particular to the mechanical constitution of the transformer 10, 25 which is particularly illustrated in FIG. 2. More precisely, the transformer 10 comprises a main core 50 and an inductive auxiliary core 60. These two cores 50, 60 receive the windings. 71-76 which form on the one hand the primary windings 11-16 and on the other hand the inductances 41 - 46. The main core also receives the windings 81 - 84, which form the secondary 21 - 26 of the transformer. As shown in Figure 3, the main core 50 has three columns 51,52,53 which receive the windings 71 - 76 and the secondary windings 81 - 86. These three columns 51 - 53 are connected in the upper part and low by portions forming the yokes 54,55. Of course, this core can be produced according to the rules of the art to optimize performance in terms of efficiency, and in particular with regard to the choice of materials used, the laminated constitution, and the assembly of the various elements that form columns and yokes, which may be monolithic or formed by the assembly of separate pieces. Thus, for small powers, it is conceivable to use magnetic circuits type EI namely that the 3 columns and one of the yokes are gathered within a generally E-shaped part, the latter being closed by a unique I-shaped yoke. From a practical point of view, the powers being important, the 3 columns are generally individualized and closed by two yokes.
    [0006] As illustrated in FIG. 4, the secondary nucleus, or inductive nucleus, 60 is also composed of three columns 61, 62, 63, which are magnetically connected by their upper and lower ends by yokes 64, 65 closing the magnetic circuits. The different columns can be made by separate sections 66, 67, between which is defined a gap 68 for adjusting the value of the inductance formed by the winding around the column. The rules of the art are applied to determine the values of these gaps in order to obtain inductance rates, corresponding to short-circuit impedances of the order of 20%, making it possible to obtain a THDI of 25 l. order of 5%. According to the invention, the auxiliary core 60 comprises a part 69 which bridges the midpoints of the columns 61,62,63. This intermediate piece or median core 69 thus defines two distinct zones of the inductive core 60 in which the primary of the transformer dedicated to a given three-phase rectifier will be wound. Thus, as illustrated in FIG. 5, it is observed that the coils 74 are wound around the column 51 of the main core 50 and of the column 61 of the inductive core 60. On the other hand, the winding 84 which constitutes the secondary 24 of the transformer is wound only around the column 51 of the main core 50.
    [0007] The characteristic part 69 of the inductive frame plays an important role in the reduction of magnetic leakage in the auxiliary core 60. More precisely, as mentioned above, the two windings 71, 74 which are wound around respectively the upper portion 91 and the low portion 92 of column 61 are traversed by separate currents. Indeed, the currents flowing through these two windings have harmonic components, and in particular harmonics of rank 5 and 7 which are in phase opposition, because they are generated by the two rectifiers 3,4, which are themselves The magnetic fluxes generated by the currents flowing through these windings are different between the upper part 91 and the lower part 92 of the column 61. The presence of the characteristic part 69 enables the magnetic fluxes generated by the currents flowing through these windings. channeling the leakage flux corresponding to the difference between the magnetic flux present in the high parts 91 and low of the same column. As a result, the neighboring conductors are traversed by a negligible leakage flux, and are therefore the seat of less losses by Joule effect. In addition, the harmonic components in particular of order 5 and 7 are less disturbed, and their cancellation because they are in phase opposition from one winding to the other is more efficient, with an improvement in the harmonic distortion rate while running.
    [0008] Of course, the configuration illustrated in FIG. 4, in which the piece 69 forming the median core is unique could be declined in different versions, and in particular be made by two separate parts, so as to form two magnetically independent half inductive core . It follows from the foregoing that the transformer according to the invention has many advantages, in particular that of significantly reducing the losses associated with the filtering function of the current produced by the incorporation of inductors. Entrance. The reduction of these losses, by channeling the different flows generated by this inductance system, makes it possible to limit the Joule losses within the conductors forming the inductances, and additionally to reduce the harmonic current to the primary current. This performance improvement and performance is achieved by maintaining optimal compactness of the transformer, particularly significant for applications requiring a limited footprint.
    权利要求:
    Claims (1)
    [0001]
    REVENDICATIONS1 /. Three-phase transformer (10) for a twelve-phase rectifier including two parallel-phase or series-connected two-phase full-wave rectifiers (3,4), comprising: a main magnetic core (50) having three columns (51,52,53) magnetically connected to each other; parallel at their ends by two yokes (54,55), and on each of which are wound: 10 - a pair of primary windings (11,14; 12,15; 13,16) connected in parallel, - two windings secondary (21-26), three of the secondary windings (21-23) wound on separate columns being connected in delta to the terminals (31-33) of the transformer connected to a first three-phase full-wave rectifier (3), the other three secondary windings (24-26) being star-connected at the transformer terminals (34-36) connected to the second three-phase full-wave rectifier (4), an auxiliary core (60) having three magnetically connected columns (61, 62, 63) at their ends by two yokes (64, 65) closing the field, on each of the columns being wound one of said pairs of primary windings (11, 14, 12, 15, 13, 16), characterized in that the core auxiliary device (60) comprises a median magnetic portion (69) connecting the midpoints of each column (61, 62, 63) located between two primary windings of the same pair (11, 14, 12, 15, 13, 16). 2 / Transformer according to claim 1 characterized in that each secondary winding of the same column is wound on one of the primary windings of said column. 3 / transformer according to claim 1, characterized in that the primary windings and / or secondary are made from a metal strip. 4 / transformer according to claim 1 characterized in that the columns of the auxiliary core (60) comprise air gaps (68).
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    同族专利:
    公开号 | 公开日
    EP3275004B1|2020-05-06|
    WO2016151225A1|2016-09-29|
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    FR3033930B1|2017-03-10|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    GB1325938A|1971-06-19|1973-08-08|Ferranti Ltd|Electric transformers|
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    法律状态:
    2016-03-29| PLFP| Fee payment|Year of fee payment: 2 |
    2016-09-23| PLSC| Search report ready|Effective date: 20160923 |
    2017-03-27| PLFP| Fee payment|Year of fee payment: 3 |
    2017-12-29| CD| Change of name or company name|Owner name: VERTIV INDUSTRIAL SYSTEMS S.A.S., FR Effective date: 20171128 |
    2018-03-26| PLFP| Fee payment|Year of fee payment: 4 |
    2020-03-25| PLFP| Fee payment|Year of fee payment: 6 |
    2021-03-25| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1552352A|FR3033930B1|2015-03-21|2015-03-21|THREE PHASE TRANSFORMER FOR DODECAPHASE RECTIFIER|FR1552352A| FR3033930B1|2015-03-21|2015-03-21|THREE PHASE TRANSFORMER FOR DODECAPHASE RECTIFIER|
    PCT/FR2016/050614| WO2016151225A1|2015-03-21|2016-03-18|Three-phase transformer for twelve-phase rectifier|
    EP16715028.3A| EP3275004B1|2015-03-21|2016-03-18|Three-phase transformer for twelve-phase rectifier|
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