PT99742B

PT99742B - HIGH TENSILE TRANSFORMER FOR A TELEVISION RECEIVER

Info

Publication number: PT99742B
Application number: PT99742A
Authority: PT
Inventors: Walter Goseberg; Wolfgang Reichon; Hans-Werner Sander
Original assignee: Thomson Brandt Gmbh
Priority date: 1990-12-10
Filing date: 1991-12-10
Publication date: 1999-02-26
Also published as: KR100194191B1; TR25836A; DE4039373A1; ES2097823T3; HK1000744A1; FI932627A; MY107209A; HU9301604D0; DE59108593D1; JPH06503448A; CA2098100A1; SG46549A1; JP3280965B2; FI932627A0; EP0561839A1; ZA919724B; HUT64660A; PT99742A; MX9102455A; WO1992010906A1

Abstract

In high-voltage transformers, in particular diode split-transformers, it is generally necessary to reduce as much as possible the size of the arrangement as a whole, for cost and weight reasons. The heat losses during operation of such a high-voltage transformer must further be reduced to such an extent that the temperature rise of the transformer does not enter a temperature range in which other parts of the circuitry of a television receiver are damaged or negatively affected. The object of the invention is to reduce losses in a high-voltage transformer, in particular to minimize electric losses. For that purpose, a practically field-free space is arranged between the primary coil and the high-voltage coil of a high-voltage transformer of the above-mentioned type. The invention has applications in television receivers, in particular high-definition receivers of HDTV standard.

Description

Á presente invenção refere-se a um transformador de alta tensão de acordo com o preâmbulo da reivindicação 1. Um tal transformador e conhecido da patente DE-OS 35 14 308. Tais transformadores geram uma tensão elevada para receptores de televisão, da ordem de grandeza de 25 KV.The present invention relates to a high voltage transformer according to the preamble of claim 1. Such a transformer is known from DE-OS patent 35 14 308. Such transformers generate a high voltage for television receivers, of the order of magnitude 25 KV.

Para com válvulas de imagem maiores, de 16:9 ou com uma diagonal do ecrã de 85 cm, são necessários valores mais elevados de alta tensão, da ordem de grandeza de 35 KV. Os transformadores para uma tao elevada alta tensão apresentam inevitavelmente uma potência de perdas mais elevada dando assim origem â produção de calor muito maior e aumentando as dimensões geométricas necessárias para a dissipação do calor.For larger image valves, 16: 9 or 85 cm diagonal of the screen, higher values of high voltage, in the order of magnitude 35 KV, are required. The transformers for such a high high voltage inevitably have a higher loss power thus giving rise to much greater heat production and increasing the geometric dimensions necessary for heat dissipation.

Um objecto da presente invenção consiste em reduzir a dissipação de potência na transformador com tais transformadores de alta tensão. 0 problema ê resolvido segundo a presente invenção como se especifica na reivindicaçãoAn object of the present invention is to reduce the power dissipation in the transformer with such high voltage transformers. The problem is solved according to the present invention as specified in the claim

1. Outros desenvolvimentos vantajosos da presente invenção sao descritos nas reivindicações secundarias,1. Other advantageous developments of the present invention are described in the secondary claims,

A presente invenção baseia-se em primeiro lugar numa analise de todos os tipos de perdas que aparecem em ligaçao com um tal transformador. Um primeiro tipo de perdas consiste nas perdas no ferro, devidas às inversões do campo magnético do núcleo, correspondentes à area do ciclo de histerese. Tais perdas apenas podem ser reduzidas utilizando materiais de ferro de melhor qualidade. Um segundo tipo de perdas consiste nas perdas no cobre devidas à resistência ohmica do fio e ao efeito de pele. Um terceiro tipo de perdas consiste nas perdas nos díodos rectificadores de alta tensão, isto é, devidas a tensão no sentido directo e à corrente de estado de ligado, à tensão e à corrente no estado de desligado e às perdas de comutaçao do estado de bloqueio para o de condução e viceversa. Um quarto tipo de perdas consiste nas perdas no dielêctrico devidas às correntes de deslocamento no isolante, normalmente feito de resina de vedaçao. No que respeita às perdas dos três primeiros tipos, há limites inferiores devidos, em particular, a motivos tecnológicos e aos componentes disponíveis. A presente invenção concentra-se no quarto tipo de perdas. A realizaçao da presente invenção baseia-se na consideração seguinte. As perdas no dielêctrico aparecem em especial na zona entre o enrolamento primário e o enrolamento secundário ou enrolamento de alta tensão, porque é aí que existem as maiores diferenças de tensão. Portanto, se fosse possível construir com êxito esta zona o mais possível livre de campos electricos, poderiam reduz.ir-se consideravelmente as perdas no dielêctrico. Segundo a presente invenção isso consegue-se simplesmente por uma divisão particularmente vantajosa das tensões de impulsos no enrolamento primário e no enrolamento secundário de modo tal que, na referida zona, os impulsos têm grosseiramente a mesma amplitude e a mesma polaridade no enrolamento primário e no enrolamento secundário. A diferença entre as tensões dos impulsos nos dois enrolamentos e então eliminada praticamente, de modo que, de maneira desejada, obtem-se ura espaço livre de campos electricos e as perdas devidas âs correntes de deslocamentoThe present invention is based primarily on an analysis of all types of losses that appear in connection with such a transformer. A first type of loss consists of losses in iron, due to inversions of the magnetic field of the nucleus, corresponding to the area of the hysteresis cycle. Such losses can only be reduced by using better quality iron materials. A second type of loss consists of losses in copper due to the ohmic resistance of the wire and the skin effect. A third type of loss consists of losses in the high voltage rectifier diodes, that is, due to the voltage in the forward direction and the current of the on state, the voltage and current in the off state and the switching losses of the blocking state. for driving and vice versa. A fourth type of losses consists of losses in the dielectric due to displacement currents in the insulator, normally made of sealing resin. With regard to the losses of the first three types, there are lower limits due, in particular, to technological reasons and the available components. The present invention focuses on the fourth type of losses. The realization of the present invention is based on the following consideration. Losses in the dielectric appear in particular in the area between the primary winding and the secondary winding or high voltage winding, because this is where the greatest voltage differences exist. Therefore, if it were possible to successfully build this zone as free as possible from electric fields, losses in the dielectric could be considerably reduced. According to the present invention, this is achieved simply by a particularly advantageous division of the pulse voltages in the primary winding and the secondary winding in such a way that, in said zone, the pulses have roughly the same amplitude and polarity in the primary winding and in the secondary winding. The difference between the impulse voltages in the two windings is then practically eliminated, so that, in a desired way, a space free of electric fields and losses due to displacement currents are obtained.

no dieléctrico são evitadas tanto quanto possível. Uma vantagem significativa consiste no facto de o espaço livre de campos eléctricos ser conseguido nao por meios do uso de dispositivos adicionais mas sim apenas por uma diposiçao engenhosa das peças que de qualquer modo já sao necessárias. Alem disso, pela redução das correntes de deslocamento no dieléctrico isolante que envolve os enrolamentos, o teor de harmónicas das tensões geradas ê reduzido. Isso conduz a menos ressonâncias naturais que, de outro modo, sao produzidas pelas correntes de deslocamento. A redução de frequências harmónicas^ conduz a uma melhoria da resistência interna e, além disso, a uma redução do ruído acústico produzido pelo transformador. Alem disso, o material que envolve os enrolamentos, de preferência uma resina vesada, fica também sujeito a tensões.on the dielectric are avoided as much as possible. A significant advantage is that the free space of electric fields is achieved not by means of the use of additional devices, but only by an ingenious arrangement of the parts that are in any case necessary. In addition, by reducing the displacement currents in the insulating dielectric that surrounds the windings, the harmonic content of the generated voltages is reduced. This leads to less natural resonances that are otherwise produced by displacement currents. The reduction of harmonic frequencies ^ leads to an improvement of the internal resistance and, in addition, to a reduction of the acoustic noise produced by the transformer. In addition, the material surrounding the windings, preferably a vesicated resin, is also subject to stresses.

A seguir explica-se a presente invenção, com referência aos desenhos anexos, cujas figuras representam:The following is explained the present invention, with reference to the accompanying drawings, whose figures represent:

Fig. 1, a configuração de um a presente invenção;Fig. 1, the configuration of the present invention;

transformador de alta tensão segundo esecond high voltage transformer and

A fig. 2, um diagrama esquemático do transformador segundo a presente invenção.Fig. 2, a schematic diagram of the transformer according to the present invention.

Na descrição, seguinte apenas são levadas em conta as tensões de impulsos efectivas no transformador. As tensões contínuas que aparecem não são consideradas porque elas nao produzem correntes de deslocamento nos dieléctricos e, por conseguinte, nao dão origem a perdas.In the following description, only the actual pulse voltages in the transformer are taken into account. The continuous voltages that appear are not considered because they do not produce displacement currents in the dielectrics and, therefore, do not give rise to losses.

Na fig. 1, o núcleo (7) da bobina, que suporta o enrolamento primário (3) é suportado no núcleo (1) do transformador. 0 enrolamento primário (3) é constituído por seis camadas. 0 fio de ligação para o exterior da camada inferior esta ligado ao terminal (b) com a tensão de serviço UB. 0 fio de ligaçao para o exterior da ultima camada está ligado ao terminal (d) e ao transístor de comutação (13), que e controlado por uma tensão (Z) de comutaçao com a frequên—In fig. 1, the core (7) of the coil, which supports the primary winding (3) is supported on the core (1) of the transformer. The primary winding (3) consists of six layers. The connecting wire to the outside of the lower layer is connected to the terminal (b) with the operating voltage UB. The connecting wire to the outside of the last layer is connected to the terminal (d) and the switching transistor (13), which is controlled by a switching voltage (Z) with the frequency—

cia do sector, no terminal (c). A tensão de impulsos no terminal (b) é zero. A tensão de impulsos no terminal (d) tem o valor total de retorno, isto é + 1 200 V. Portanto, a tensão de impulsos aumenta constantemente de espira para espira, desde o valor zero, no terminal (b), até ao valor máximo, no terminal (d). Isto significa que a tensão de impulsos diminui em cerca de 16% ao longo do comprimento axial da camada superior do enrolamento (3) e a tensão de impulsos na extremidade direita da camada superior tem um valor de + 1000 V. Portanto, esta tensão de impulsos é substancialmente constante ao longo do comprimento axial do núcleo (7) da bobina na camada superior do enrolamento (3) e tem um valor médio de 1 100 V.sector, at terminal (c). The pulse voltage at terminal (b) is zero. The pulse voltage at terminal (d) has the total return value, ie + 1 200 V. Therefore, the pulse voltage constantly increases from loop to loop, from zero, at terminal (b), to the value maximum at terminal (d). This means that the pulse voltage decreases by approximately 16% along the axial length of the upper layer of the winding (3) and the pulse voltage at the right end of the upper layer has a value of + 1000 V. Therefore, this voltage of pulses is substantially constant along the axial length of the core (7) of the coil in the top layer of the winding (3) and has an average value of 1,100 V.

Disposto por cima do núcleo (7) da bobina com o enrolamento primário (3) está o núcleo compartimentado (2) da bobina, que tem um total de 16 células (Ka) a (Kp), separadas por paredes (8), que são preenchidas com enrolamentos parciais (4a) a (4p) do enrolamento secundário de alta tensão (4). 0 fio de ligaçao para o exterior proveniente da camada superior do primeiro enrolamento parcial (4a) esta ligado à terra. Cada um dos fios de ligaçao para o exterior na base de uma célula (K) está acoplado ao ânodo de um diodo rectificador de alta tensão (6), cujos cátodos estão sempre ligados ao fio de ligaçao para o exterior proveniente da extremidade superior do enrolamento parcial seguinte (4). 0 fio de ligaçao para o exterior proveniente da base do enrolamento parcial final (4p) na célula (Kp) forma o terminal de alta tensão (a). 0 processo de bobinagem de todo o enrolamento secundário (4) começa na base da célula (Kp). Como está sempre colocado um diodo (6) entre cada par de células, proporcionamse 15 díodos (6) para um total de 16 células (k) . Uma alta tensão UH de 32 KV existe no terminal (a). Admitidos esses valores, resulta sempre um impulso de + 1 100 V na base de cada célula (K), idêntico para todas as células. Na extremidade superior do enrolamento (4) resulta um impulso de - 1300Arranged above the core (7) of the coil with the primary winding (3) is the compartmentalized core (2) of the coil, which has a total of 16 cells (Ka) to (Kp), separated by walls (8), which they are filled with partial windings (4a) to (4p) of the secondary high voltage winding (4). The outer connecting wire from the top layer of the first partial winding (4a) is connected to earth. Each of the outer connecting wires at the base of a cell (K) is coupled to the anode of a high voltage rectifier diode (6), whose cathodes are always connected to the outer connecting wire from the upper end of the winding following partial term (4). The outer connecting wire from the base of the partial end winding (4p) in the cell (Kp) forms the high voltage terminal (a). The winding process of the entire secondary winding (4) begins at the base of the cell (Kp). As a diode (6) is always placed between each pair of cells, 15 diodes (6) are provided for a total of 16 cells (k). A 32 KV UH high voltage exists at terminal (a). Assuming these values, a + 1 100 V impulse always results at the base of each cell (K), identical for all cells. At the upper end of the winding (4) an impulse of - 1300 results

V.V.

Por conseguinte, estão presentesTherefore, they are present

impulsos com uma amplitude substancialmente constante de + 1 100 V ao longo da camada superior do enrolamento (3). Por outro lado, como atrás se descreveu, existem impulsos de amplitude constante de + 1200 V através do enrolamento de alta tensão (4) na zona associada ao enrolamento 3, isto ê, na zona das extremidades das células. Aparte isso, os impulsos no enrolamento (3) e no enrolamento (4) sao isócronos. Portanto ja nao existe praticamente qualquer diferença de potencial entre os impulsos no enrolamento (3) e os impulsos no enrolamento (4), de modo que resulta um espaço sem campos electricos, como está indicado com as linhas a traceado (F).pulses with a substantially constant amplitude of + 1 100 V along the top layer of the winding (3). On the other hand, as described above, there are pulses of constant amplitude of + 1200 V through the high voltage winding (4) in the zone associated with winding 3, that is, in the zone of the cell ends. Apart from that, the impulses in the winding (3) and the winding (4) are isochronous. Therefore, there is practically no potential difference between the impulses in the winding (3) and the impulses in the winding (4), so that a space without electric fields results, as indicated by the dashed lines (F).

Os impulsos na extremidade superior dos enrolamentos (4) têm de facto uma polaridade negativa nao conveniente para a formaçao do espaço sem campos. Porem os impulsos presentes neste ponto estão suficientemente distantes do enrolamento primário (3) para que nao provoquem já quaisquer correntes de deslocamentos significativos através do isolante.The impulses at the upper end of the windings (4) do in fact have a negative polarity not suitable for the formation of the gap without fields. However, the impulses present at this point are sufficiently distant from the primary winding (3) so that they no longer cause any significant displacement currents through the insulator.

A extremidade superior do primeiro enrolamento (4a) está ligada á terra e portanto nao conduz qualquer tensão de impulso e, por outro lado, a extremidade inferior do enrolamento final (4p), que está ligada â terra através da capacidade da válvula de imagem, também nao conduz qualquer tensão de impulso. As relações das tensões destes dois enrolamentos sao portanto diferentes das dos outros enrolamentos (4b) a (4o). Para também produzir as relações de amplitudes desejadas entre as tensões de impulsos nesta zona, e vantajoso, em contraste com as restantes células, ter apenas metade das bobinas nas células (Ka)e (Kp). 0 enrolamento primário (3) e de preferência enrolado com fio torcido para manter num valor baixo as perdas por efeito de pele.The upper end of the first winding (4a) is connected to earth and therefore does not conduct any impulse voltage and, on the other hand, the lower end of the final winding (4p), which is connected to earth through the capacity of the image valve, it also does not conduct any impulse voltage. The voltage relationships of these two windings are therefore different from those of the other windings (4b) to (4o). To also produce the desired amplitude ratios between the pulse voltages in this zone, it is advantageous, in contrast to the other cells, to have only half the coils in the cells (Ka) and (Kp). The primary winding (3) is preferably wound with twisted yarn to keep skin-effect losses low.

A fig. 2 mostra o esquema do circuito associado com a fig. 1. 0 condensador (14), essencialmente formado pelo ânodo terminal (camada de ânodo) do tubo de imagem (15), está ligado ao terminal (a) que conduz a alta • tensão (UH). 0 diodo (6b) corresponde portanto ao primeiroFig. 2 shows the circuit diagram associated with fig. 1. The condenser (14), essentially formed by the terminal anode (anode layer) of the image tube (15), is connected to the terminal (a) that leads to high voltage (UH). The diode (6b) therefore corresponds to the first

díodo da fig. 1 entre a base da célula (Ka) e o condutor de saída na extremidade superior da célula (Kb) . 0 díodo final (6p) corresponde ao díodo entre a extremidade inferior do enrolamento da célula (Ko) e o fio de ligaçao para o exterior superior da célula final (Kp).diode of fig. 1 between the base of the cell (Ka) and the output conductor at the top end of the cell (Kb). The final diode (6p) corresponds to the diode between the lower end of the cell winding (Ko) and the connecting wire to the upper outside of the final cell (Kp).

Ê também possivel subdividir o enrolamento primário (3) em vários elementos parciais que ficam uns adjacentes aos outros na direcção axial no núcleo (1) e estão cablados em paralelo entre os terminais (b) e (d). Geralmente, a amplitude da camada superior do enrolamento primário (3) varia ao longo do comprimento axial. Isso pode ser levado em conta pelo facto de as células (Ka) a (Ko) serem preenchidas, por conseguinte, de maneira diferente, de modo que os impulsos de cada um dos enrolamentos parciais (4a) a (4p) tenham também correspondentemente amplitudes diferentes nas bases das células. 0 factor de enchimento das células (K) com os enrolamentos parciais (4) diminuiram então da esquerda para a direita dos núcleos das bobinas (7) e (2), tal como sucede com a amplitude dos impulsos na camada superior do enrolamento (3), que diminui, na fig. 1, de + 1 200 V para + 1 000 V.It is also possible to subdivide the primary winding (3) into several partial elements that are adjacent to each other in the axial direction in the core (1) and are wired in parallel between the terminals (b) and (d). Generally, the amplitude of the upper layer of the primary winding (3) varies along the axial length. This can be taken into account by the fact that the cells (Ka) to (Ko) are therefore filled differently, so that the impulses of each of the partial windings (4a) to (4p) also have correspondingly amplitudes different at the bases of cells. The filling factor of the cells (K) with the partial windings (4) then decreased from left to right of the coil cores (7) and (2), as with the amplitude of the pulses in the upper layer of the winding (3 ), which decreases, in fig. 1, from + 1 200 V to + 1 000 V.

Claims

High voltage transformer for a television receiver with a secondary winding (4) arranged above it, whose partial windings (4a) to (4p) are placed in cells (K) of a compartmented coil core

(2) and are connected to each other through diodes (6), characterized in that the primary winding (3) and the secondary winding (4) are subdivided and polarized in such a way that they produce pulses of approximately equal amplitude and polarity in the areas of the windings (3,4) adjacent to each other and because a space almost free of electric fields is formed between the windings (3,4).

Transformer according to claim 1, characterized in that the primary winding (3) is wound in layers, the various layers being situated on top of each other, and the outlet wire (b) of the lower layer is provided to connect the service voltage (UB) and the output wire (d) of the upper layer to be connected to a periodic switch (13).

- 3 ‘

Transformer according to <claim 2, characterized in that the partial windings (4a) to (4p) are polarized in such a way that there is always a positive pulse in the outlet wire from the base of each of the cells (K).

- claim 3, and partial windings

Transformer according to ized by the number of cells (K) (4a) to (4p) being chosen sufficiently large so that the positive pulse at the base of a cell (K) has approximately the same amplitude as the positive pulse in the layer of the primary winding (3).

- 5 ^A transformer according to claim 1, characterized in that always one diode (6) connected by its anode to the base of the outlet edge of a cell (K) and the cathode of each said diode being connected to wire the top layer of the partial winding (4) of the next cell (K).

- 6 ^â -

Transformer in wake up with the claim 1, characterized by the principle winding secondary (4) constitute the terminal (a) what provides the high voltage (UH). _ ?The _ Transformer in wake up with the claim 1, characterized in that the winding primary

(3) be constituted by several partial windings (3a) to (3c), connected in parallel and arranged adjacent to each other in the axial direction of the core (2) of the coil.

- 8 ^A transformer according to claim 1, characterized in that the transformer is designed as transformer with separating diodes.

_ what _

Transformer according to claim 1, characterized in that the cells (K) are filled differently by the partial windings, so that the impulses at the base of each cell are suitable

I '4 approximately the same amplitude as the impulses in the neighboring winding of the primary winding (3).

- Transformer according to claim 1, characterized in that the first (Ka) and the last (Kp) cell are, relative to the other cells (Kb) to (Ko), only half filled with the partial windings (4).

The applicant claims the priority of the German patent application, filed on December 10, 1990, under No. 40 39 373.9.

Lisbon, December 10, 1991.

smcSBuI

RESUME

HIGH VOLTAGE TRANSFORMER FOR A TELEVISION RECEIVER

The invention relates to a high voltage transformer for a television receiver.

For a high voltage transformer, in particular a transformer with separation diodes, it is generally required that the entire device, for reasons of cost and weight, have to be provided as small as possible, having also the thermal losses during the operation of such a high voltage transformer is reduced sufficiently so that the heating of the transformer does not reach temperatures at which other components of the circuit of a television receiver are damaged or suffer disturbing influences.

The object of the invention is to minimize the losses of a high voltage transformer, in particular electrical losses.

According to the invention, this problem is solved for a high voltage transformer of the aforementioned type forming a space (F) between the primary winding (3) and the high voltage winding (4) almost free of electric fields.

The invention has application in television receivers, in particular in television receivers with a high number of lines for the HDTV high definition television standard.