An arragement of windings of a HV insulation transformer

Description

[0001] The subject of the invention is an arrangement of windings of a HV insulation transformer for power supply devices with multiple outputs whose outputs must be insulated from the primary side and between each other, to withstand very high voltages.

[0002] Multiple outputs power supply devices use various high voltage insulation transformers to provide high voltage galvanic insulation. This allows to isolate each output from the input of the power supply device as well as each output from the other output of the supply device. There are two ways to build a high voltage insulation transformer. One is to insulate the magnetic path of the transformer, by dividing a core into two pieces and introducing an insulation gap between them. The second way consist on using a HV insulated wires. This method creates an opportunity to look at an optimized way of transferring energy between primaries and secondaries in high voltage isolation power supply devices.

[0003] There are known high voltage power supply devices with multiple outputs provided with the separate high voltage insulation transformers where the primary and the secondary windings of a single transformer are wound on the same core and the high voltage insulation is provided by use of the wire insulating material. There are also known solutions, where the windings are wound with low voltage wires and the high voltage insulation is provided by use of the bobbins. There are known pulse transformers having a core composed of a two pieces, insulated between each other with air, resin or another insulating material, usually operating at the resonant frequency to reduce impact of leakage inductance. The known multiple transformers solution for the power supply device creates relatively bulky solutions. The power supply device become quite large and expensive, as every output of the power supply device uses a separate high voltage insulated transformer. In the known pulse power supply devices the controllers sense primary currents to protect the circuit against overload or shorted output. For a few separate transformers, the sensing circuits can be applied to monitor primary currents, which are dependent on secondary currents. There are known designs, where the isolating transformer comprises a single primary and multiple secondary windings, and the sensing circuit measures total primary current without the possibility of monitoring individual secondary currents. In the known versions of the power supply devices with HV insulated transformers having multiple outputs there are separate transformers for each of the outputs, providing galvanic isolation between primaries and secondaries as well as between all of the secondaries. It is essential in high voltage power supply devices to introduce current measurements for protection and/or monitoring on the primary side, since the secondary monitoring must be done at the high voltage site and isolation of the current feedback is expensive and difficult. The known solution with separate transformers for each of the outputs create relatively bulky solutions, so the idea is to use a single HV insulated transformer with multiple outputs, to save space and reduce costs of the power supply device. In typical transformers equipped with a single primary and multiple secondary windings, the current measurement performed on the primary side allows indirect monitoring of total output currents without the information about sharing between the secondary outputs. In this case it is impossible to determine which output is overloaded, because the total primary current could be within the overall load limit of the transformer. It was found that for a certain winding arrangement, the primary measurements allow to determine output current for each output separately. The relevant prior art is presented in the international applications WO2009/138099 (which shows the features of the preamble of claim 1) and WO2005/057769.

[0004] The essence of the invention comprising a secondary winding superimposed on a primary winding forming a pair of windings wound on a transformer core is that at least two pairs of windings are placed on the same one common core in such a way that any windings of each pair of windings are not overlapping the neighboring pair of windings. The primary windings are connected in parallel and each of the primary winding has a current sensor adapted for measuring the current of its respective secondary winding. Preferably each pair of windings has an insulation gap situated between the external surface of the primary windings and the internal surface of the secondary windings. Preferably the gap between the external surface of the primary winding and the internal surface of the secondary winding, an insulation shell is inserted having a shape compatible with the shape of the core.

[0005] Preferably on the outer side of the insulation shell a series of press-fits are placed for positioning the secondary windings exactly in superposition area on the primary windings.

[0006] Preferably the insulation shell is provided with ribs which are distributed radially along the internal side of shell walls on both sides of the shell for proper positioning the core and primary windings.
Alternatively the insulation shell is made in the form of a insulation mesh.
Preferably around the perimeter of the core transformer the four pairs of windings are place uniformly.
Preferably the primary windings and the secondary windings are coated with one or more insulation layers.
Preferably the transformer core is made as a solid ferromagnetic body in the shape of a toroid.
Alternatively the transformer core is made as one body with the insertion of the other magnetic material having different magnetic permittivity in its magnetic path. Alternatively the transformer core is made as a stack of separate ring plates situated one on a top of the other.

[0007] The advantage of the inventive transformer is that it assures the assessment of the individual secondary current of each outputs of the power supply device by sensing the primary current. The use of single common core transformer as opposed to the multiple transformers allows the size reduction of the power supply device.

[0008] transformer windings in an axonometric view, fig. 3 - the second embodiment of the transformer windings in an axonometric view, fig.4 - transformer windings from fig. 3 after detaching a half of the transformer shell.

[0009] The transformer for the power supply device has a magnetic core ring 1, on which at least two separated primary windings 2 are wound. The primary windings are connected in parallel. Each primary winding 2 is equipped with a current sensor 3. Around each of the primary winding 2 a separate secondary winding 4 is wound in such a way that winding 4 is spatially superimposed on the primary winding 2, where a certain distance is present between the external surface of the winding 2 and the internal surface of the winding 4 forming an insulation gap 5 between them.

[0010] The gap 5 can be filled with a potting insulation material assuring the proper insulation level between both windings 2 and 4, which is not shown in the drawing. The primary windings 2 and the secondary windings 4 are forming pairs of windings 6 having one primary and one secondary winding in each pair. All pairs of the windings 6 are distributed uniformly along the perimeter of the core 1 in such a way that the neighboring pairs are not overlapping each other.

[0011] In the second embodiment of the invention an insulation shell 7 made of plastic is inserted in the gap 5. The shell 7 is composed of two halves 7a and 7b and has a shape similar to core 1, thus covers the core 1 except of primary windings terminals leaded out of the shell 7, which is not shown in the drawing. The outer side of the side wall of the shell 7 is provided with a series of press-fits 8 placed on its perimeter in order to position the secondary windings 4 on top of the primary winding 2. The shell 7 is provided with ribs 9 which are distributed radially along both inner sides of the side walls.

[0012] The insulation shell 7 can be realized as mesh construction which is not shown in the drawing. In such a case the press-fits 8 are needless.

[0013] In both embodiments of the invention the primary windings 2 and the secondary windings 4 can be coated with one or more insulation layers. In such embodiment where the primary and the secondary windings are coated with the insulating layer, the gap 5 can be eliminated, which means that the primary and the secondary windings of the pair 6 remain in contact.

[0014] The transformer according to the both embodiments of the invention could be placed in an insulating housing and covered with an insulating cover which is not presented in the drawing. The housing can be made out of a resin by molding and in such a case, the shell can be omitted, because the resin insulation between the windings replaces the shell.

[0015] In the exemplary embodiment of the invention the magnetic core 1 is made as a solid ferromagnetic body in the shape of toroid, but it can be made as one body with the insertions of the other magnetic material having different magnetic permittivity. Also the core 1 could be made of some separate ring plates situated one on the top of the other forming a stack. The number of the pairs of windings in the exemplary embodiment is four, but it may be different on the assumption that the pairs 6 do not overlap each other.

[0016] The principle of operation of the inventive transformer is the following. All the primary windings 2 equipped with current sensors 3 are connected in parallel and driven from an AC source inducing voltages in the secondary windings 4. The sensors 3 measure primary currents which are dependent on the secondary ones, so indirectly the sensors sense secondary currents. Even though all pairs of the windings 6 are placed on the same common core 1, the individual currents flowing through the primary windings 2 are dependent on the currents of their respective secondary windings 4 with negligible impact of the currents of neighboring pairs 6. Each pair of the windings 6 acts like an independent transformer, since the magnetic coupling within each pair of the windings is much higher than between the neighboring pairs, hence the crosstalk between the neighboring windings is negligible. This is a very important feature, which simplifies detection of the overload or short circuit of any individual secondary winding. This is a very essential feature of the transformer operating in HV applications where there is no feedback from the secondaries to the primary controller, which is a part of the supply device.

[0017] In the presented embodiment of the invention the pair of winding 6 is formed such that the secondary windings 4 are placed on top of the primary windings 3 but it is understand to those skilled in the art that the reverse relation between windings is possible. When the secondary windings is placed under the primary windings, the scope of the protection will be the same.

Claims

1. An arrangement of windings of a HV insulated transformer for power supply device comprising a secondary winding (4) superimposed on a primary winding (2) forming a pair of windings (6) wound on a transformer core (1), wherein at least two pairs of windings (6) are placed on the same one common transformer core (1) in such a way that any windings (2, 4) of each pair of windings (6) are not overlapping the windings (2, 4) of the neighboring pair of windings (6) and where the primary windings (2) are connected in parallel, characterized in that each of the primary winding (2) has a current sensor (3) adapted for measuring the current of its respective secondary winding (4).

2. An arrangement according to claim 1, characterized in that each pair of windings (6) has an insulation gap (5) situated between the external surface of the primary windings (2) and the internal surface of the secondary windings (4).

3. An arrangement according to claim 2, characterized in that in the gap (5) between the external surface of the primary winding (2) and the internal surface of the secondary winding (4) an insulation shell (7) is inserted having a shape compatible with the shape of the transformer core (1).

4. An arrangement according to claim 3, characterized in that on the outer side of the insulation shell (7) a series of press-fits (8) are placed for positioning the secondary windings (7) exactly in superposition area on the primary windings (2).

5. An arrangement according to claim 3, characterized in that the shell (7) is provided with ribs (9) which are distributed radially along the internal side of shell walls on both sides of the shell for proper positioning the core (1) and primary windings (2).

6. An arrangement according to claim 3, characterized in that the insulation shell (7) is made in the form of a insulation mesh.

7. An arrangement according to claim 1, characterized in that four pairs of windings (6) are placed uniformly around the perimeter of the transformer core (1).

8. An arrangement according to any of the previous claims, characterized in that the primary windings (2) and the secondary windings (4) are coated with one or more insulation layers.

9. An arrangement according to any of the previous claims, characterized in that the transformer core (1) is made as a solid ferromagnetic body in the shape of a toroid.

10. An arrangement according to claim 9 ; characterized in that the transformer core (1) is made as one body with the insertion of the other magnetic material having different magnetic permittivity in its magnetic path.

11. An arrangement according to claims 1-8, characterized in that the transformer core (1) is made as a stack of separate ring plates situated one on top of the other.

Ansprüche

1. Eine Anordnung von Wicklungen eines Hochspannungsisolierungstransformators für eine Stromversorgungseinrichtung, die aus einer Sekundärwicklung (4), aufgesetzt auf einer Primärwicklung (2) besteht und welche ein Paar von Wicklungen (6), das um einen Transformatorkern (1) gewickelt ist, bilden, wobei mindestens zwei Paare von solchen Wicklungen (6) auf demselben gemeinsamen Transformatorkern (1) in der Weise angeordnet sind, dass keine der Wicklungen (2, 4), die ein Paar bilden (6), die Wicklungen (2, 4) des benachbarten Paares von Wicklungen (6) überlappt, und wobei die Primärwicklungen (2) parallel geschaltet sind, dadurch gekennzeichnet, dass jede der Primärwicklungen (2) einen Stromsensor (3) besitzt, der dazu dient, den Strom in der Sekundärwicklung (4), die mit der ihr entsprechenden Primärwicklung (2) ein Paar darstellt, zu messen.

2. Eine Anordnung von Wicklungen gemäß Anspruch 1, dadurch gekennzeichnet, dass jedes Paar von Wicklungen (6) einen Isolationsspalt (5) besitzt, der sich zwischen der Außenfläche der Primärwicklungen (2) und der Innenfläche der Sekundärwicklungen (4) befindet.

3. Eine Anordnung von Wicklungen gemäß Anspruch 2, dadurch gekennzeichnet, dass sich im Spalt (5) zwischen der Außenfläche der Primärwicklungen (2) und der Innenfläche der Sekundärwicklungen (4) eine Isolationsschale (7) befindet, deren Form an die Form des Transformatorkerns (1) angepasst ist.

4. Eine Anordnung von Wicklungen gemäß Anspruch 3, dadurch gekennzeichnet, dass sich auf der Außenseite der Isolationsschale (7) eine Reihe von Rillen (8) befindet, deren Aufgabe ist, die Position der Sekundärwicklungen (4) exakt zentrisch zu den ihnen entsprechenden Primärwindungen (2) zu bestimmen.

5. Eine Anordnung von Windungen gemäß Anspruch 3, dadurch gekennzeichnet, dass die Isolationsschale (7) mit Rippen (9) versehen ist, die radial entlang der Innenseite der Schalenwände auf beiden Seiten der Schale verteilt sind und der richtigen Positionierung des Kerns (1) und der Primärwindungen (2) dienen.

6. Eine Anordnung von Windungen gemäß Anspruch 3, dadurch gekennzeichnet, dass die Isolationsschale (7) in Form eines Isolationsgewebes ausgeführt ist.

7. Eine Anordnung von Windungen gemäß Anspruch 1, dadurch gekennzeichnet, dass vier Paare von Wicklungen (6) gleichmäßig um den Transformatorkern (1) herum angeordnet sind.

8. Eine Anordnung von Windungen gemäß irgendeinem der vorherigen Ansprüche, dadurch gekennzeichnet, dass die Primärwindungen (2) und die Sekundärwindungen (4) mit einer oder mehreren Isolationsschichten überzogen sind.

9. Eine Anordnung von Windungen gemäß irgendeinem der vorherigen Ansprüche, dadurch gekennzeichnet, dass der Transformatorkern (1) als fester ferromagnetischer Körper in Form eines Torus ausgeführt ist.

10. Eine Anordnung von Windungen gemäß Anspruch 9, dadurch gekennzeichnet, dass der Transformatorkern (1) als ein Stück ausgeführt ist, das aus einem magnetischen Material mit einer anderen Permittivität besteht, welches einen Teil der magnetischen Bahn darstellt.

11. Eine Anordnung von Windungen gemäß den Ansprüchen 1-8, dadurch gekennzeichnet, dass der Transformatorkern (1) als Stapel aus einzelnen magnetischen Ringscheiben, eine über der anderen angeordnet, ausgeführt ist.

Revendications

1. Agencement d'enroulement d'un transformateur d'isolation haute tension utilisé pour l'alimentation électrique comprenant les enroulements secondaires (4) embobinés sur les enroulements primaires (2) et constituant un couple (6) enroulé sur le noyau du transformateur (1), où deux couples au moins de ces enroulements (6) sont placés sur le même noyau du transformateur (1) de manière à ce qu'aucun des enroulements (2, 4) constituant un couple (6) ne chevauche les enroulements (2, 4) du couple adjacent d'enroulements (6) et où les enroulements primaires (2) sont raccordés en parallèle, caractérisé en ce que chaque enroulement primaire (2) possède un détecteur de courant (3) servant à mesurer le courant dans l'enroulement (4) qui constitue le couple avec l'enroulement primaire (2).

2. L'agencement d'enroulement selon la revendication 1, caractérisé en ce que chaque couple d'enroulements (6) possède une coupure d'isolation (5) située entre la surface extérieure des enroulements primaires (2) et la surface intérieure des enroulements secondaires (4).

3. L'agencement d'enroulement selon la revendication 2, caractérisé en ce que dans la coupure d'isolation (5), entre la surface extérieure des enroulements primaires (2) et la surface intérieure des enroulements secondaires (4), est insérée une carapace isolant (7) dont la forme est adaptée à la forme du noyau du transformateur (1).

4. L'agencement d'enroulement selon la revendication 3, caractérisé en ce que sur la surface extérieure de la carapace isolant (7) se trouve une série de rainures (8) destinée à positionner les enroulements secondaires exactement au centre au dessus de leur enroulements correspondants primaires (2).

5. L'agencement d'enroulement selon la revendication 3, caractérisé en ce que la carapace isolant (7) possède des nervures (9) qui sont réparties de façon radiale le long des parois intérieures de la carapace de ses deux côtés qui servent à positionner correctement le noyau (1) des enroulements primaires (2).

6. L'agencement d'enroulement selon la revendication 3, caractérisé en ce que la carapace isolant (7) est faite en grille isolante.

7. L'agencement d'enroulement selon la revendication 1, caractérisé en ce que les quatre couples d'enroulement (6) sont répartis uniformément le long de la circonférence du transformateur (1).

8. L'agencement d'enroulement selon une quelconque des revendications précédentes, caractérisé en ce que les enroulements primaires (2) et les enroulements secondaires (4) sont revêtus d'une ou plus de couches isolantes.

9. L'agencement d'enroulement selon une quelconque des revendications précédentes, caractérisé en ce que le noyau du transformateur (1) est fait en matériau ferromagnétique d'une forme de tor.

10. L'agencement d'enroulement selon la revendication 9, caractérisé en ce que le noyau du transformateur (1) est exécuté comme une seule pièce dont la composition comprend un autre matériau magnétique ayant une autre permittivité, constituant une partie de???

11. L'agencement d'enroulement selon les revendications 1 à 8, caractérisé en ce que le noyau du transformateur (1) est fait comme une pile d'anneaux magnétiques empilés les uns sur les autres.

Drawing