CZ2000524A3 - Circuit arrangement of converter transformer with fill-wave rectifier - Google Patents

Abstract

The solution concerns transformer and two-way wiring rectifiers for power converters with semiconductor switches in particular for the acquisition of higher or very high high voltages. Inverter transformer wiring the two-way rectifier has a secondary winding the individual sections (7) in one branch and a section (8) in the second branch that is in series interconnected in front of the co-ordinated rectifier diodes (5) and (6). Each section (7) in the first branch and each section (8) in the second branch the secondary winding always forms one threaded layer secondary winding, always starting on the same side the secondary coils and ending up the other side when all the winding sections are wound with the same sense. Involvement is also possible modify it for other cases. For example, for converter transformer with one-way rectifier.

Description

(57)

The solution relates to the connection of a transformer and a two-way rectifier in power converters with semiconductor switches, especially intended for obtaining higher or very high voltages. The transformer wiring with the two-way rectifier has the secondary winding of the transformer divided into individual sections (7) in one branch and sections (8) in the other branch, which are connected in series in front of identically connected rectifier diodes (5) and (6). Each section (7) in the first strand and each section (8) in the second strand of the secondary winding each form a threaded layer of secondary winding, starting always on the same side of the secondary coil and ending on the other side thereof. The wiring can also be modified analogously for other cases. For example, for a converter transformer with a one-way rectifier.

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Connection of converter transformer with two-way rectifier

Technical field

The present invention relates to a novel transformer and two-way rectifier circuitry for power converters with semiconductor switches, particularly intended for obtaining higher or very high voltages.

BACKGROUND OF THE INVENTION

Wiring and design of circuits with transformers and rectifiers of power converters operating at medium and higher frequencies and transforming the original supply voltage to a much higher level is associated with problems. Especially when it is necessary to obtain a very high output voltage, together with a relatively high output current. The main difficulties are caused by the internal mutual capacitances and inductances of the individual parts of the high-voltage winding, which at high operating frequencies cause considerable local reactive currents, which in turn cause considerable power losses on the real resistance of these winding parts. This causes a considerable heating of the windings, deteriorating the efficiency of the entire inverter and increases the technical demands on heat dissipation. To date, this has been minimized by several means. The secondary high-voltage coils were designed to have as little intrinsic capacities as possible. So they wound in a cross. A somewhat thicker conductor was used than required in terms of standard current load. Mainly, however, the lower operating frequency of the inverter was used. This, however, proportionally lost the main advantage of the converter, which is the small size of its power transformer.

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These disadvantages of the prior art solutions are avoided by the circuitry according to the invention in that the secondary winding is carried out in two branches. Each of these branches is then further divided into sections with separate outlets. Among the terminals of these 9 9 9 9 9 9 9

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999 999 99 9999 ·· ·· sections, always the end of the previous one and the beginning of the next one, are connected in the same sense by the voltage corresponding to the sub-part of the rectifier, dimensioned for the total voltage of the whole rectifier branch. At the same time, before the beginning of the first section and after the end of the last section, the corresponding parts of the rectifier branch are also included in the same sense. Their second terminals are connected to the output terminals of the inverter, and shielding foils of the end sections can also be connected to them. By proposing the distribution of the entire branch by the rectifier parts, the individual AC voltage and current sections are separated from each other, thereby minimizing their reactive components.

BRIEF DESCRIPTION OF THE DRAWINGS

The circuit according to the invention is shown schematically in FIG. 1 in the accompanying drawing.

DETAILED DESCRIPTION OF THE INVENTION

In the exemplary embodiment, the circuit according to the invention is made such that, on a two-column ferrite transformer core 4, each of its pillars is wound first on the first, first part 1 and second, second part 2 of the primary winding. terminals 3 of the primary winding. On both windings, the lower layers of the shielding foil 9 are laid in isolation, which are connected together, on the one hand to the feedback terminal 12 and to the ground via the feedback resistor Π. Above these layers, the windings of the individual sections 7 and 8 of the first and second branches of the secondary winding are successively wound on the first and second posts. These are always wound in only one layer, starting identically on one side and ending on the other side of the coil of the respective branch. All sections 7 and 8 of both branches of the secondary winding have the same number of turns. The beginnings of the first sections 7 and 8 closest to the respective portions of the primary windings are connected via one of a pair of equally polarized end rectifier diodes 15 and 16 of the first and second branches of the secondary winding respectively to the lower shielding foils 9 and to the feedback terminal 12 and via the feedback resistor 13 to ground. Winding ends of these first sections, first 7 i 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 • 9 9 9 9 9 9 9

999 999 99 9999 99 99 The second 8 branches of the secondary winding are connected to the starts of the subsequent successive winding sections 7 and 8 of the two branches of the secondary winding through the first rectifier diodes 5 and 6 of the first and second branches of the secondary winding. The ends of the second sections 7 and 8 of the first and second branches of the secondary winding are again via the other rectifier diodes 5 and 6 of the first and second branches of the secondary winding to the next starts of the subsequent sections. branches of secondary winding. In this way, the wiring of the starts and ends of each of the subsequent successive sections 7 and 8 and the rectifier diodes 5 and 6 of the two branches of the secondary winding is repeated in sequence only after the wiring of the starts of the last sections. The ends of the last sections 7 and 8 are then connected, via the same direction as the rectifier diodes 5 and 6 to the polarized, terminal rectifier diodes 15 and 16, to the output high voltage terminal 10. Generally, the branches of the secondary windings thus connected must have the winding senses of the sections of the first branch 5 and the second branch 6 interconnected opposite to the parallel connected portions of the primary winding. Comparing resistors 13 can also be connected in parallel to the rectifier diodes 5 and 6 as well as to the end rectifier diodes 15 and 16 of the first and second branches of the secondary winding.

The circuit according to the invention operates as follows. By applying a voltage of one polarity to the connection terminals 3 of the primary winding, voltages of the same magnitude and the same waveform are induced in each section 7 of the first branch of the secondary winding. If, in this half-period, they have just polarity such that the rectifier diodes 5 of this branch are conductive, then all the partial voltages of the sections will be summed and the output high voltage outlets 10 will be the voltage corresponding to their sum. At the same time, in the second branch of the secondary winding, a voltage of opposite polarity is induced on its sections 8 so that the rectifier diodes 6 of the second branch will be non-conductive. Thus, the voltages of the individual sections 8 do not add up and have no effect on the output high voltage outlets. In the next half period of the voltage applied to the connection terminals 3 of the primary winding, its polarity is reversed from the previous one. This also reverses the function of both the branches of the secondary winding, their sections, their rectifiers and the end diodes, and the summation voltage to the output of the high voltage outlet 10 is supplied by the second branch of the secondary winding. Considering that all successive sections are always at the beginning and the end of each section as well as at the same time

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00 0 0 00 0 0 «0 0 0 0 0 0 0 000 00 0 0 0 000 0000 000 000 00 0000 00 00 practically in all their parts, alternating voltages of the same magnitudes and waveforms do not apply practically at all to their operation mutual capacity. The resulting rectifier activity of this circuit is thus identical to that of a conventional two-way rectifier, but without any parasitic capacities. This enables this circuit to operate with very low intrinsic losses even at relatively high operating frequencies, whose upper limits are then limited mainly by the frequency characteristics of the other circuit elements involved. For this connection, it is of course advantageous to use for all, involved in the rectifier diodes 5,6, 15, 16, diodes with avalanche or zener characteristic in the closing region, which provides both its own overvoltage protection of these circuit elements and also uniform distribution of DC potentials which remain on the individual winding sections 7 and 8 of the branches of the secondary winding at a time when the connected diodes are not currently in the conductive mode. However, avalanche diodes have a rather limited power dissipation, which may not be sufficient in all applications. In this case, it is also possible to connect comparing resistors 13 in parallel to the diodes, which support the compensating function of the reverse characteristics of the diodes in terms of power.

Industrial applicability

The circuit according to the invention, which is described by way of example, can also be modified analogously for other cases. For example, for a converter transformer with a one-way rectifier.

Claims (5)

PATENT CLAIMS A converter transformer with a two-way rectifier according to the invention, characterized in that the secondary winding of the transformer is divided into individual sections (7) in one branch and (8) in the other branch, which are connected in series via consecutively connected rectifier diodes. 5) and (6). Wiring according to claim 1, characterized in that each section (7) in the first branch and each section (8) in the second branch of the secondary winding each form a threaded layer of secondary winding starting on the same side of the secondary coil and ending on its second side, when all winding sections are wound in the same sense. Wiring according to items 1 and 2, characterized in that after the last, possibly before the first sections (5) and (6) of the secondary windings in both branches, which are connected to the winding ends of the last sections or to the beginning of the first sections, terminal diodes (15) and (16) that are polarized in the same sense as the rectifier diodes (5) and (6) of the still shielding film (9). Wiring according to Claims 1, 2 and 3, characterized in that comparing resistors (13) are connected in parallel to the rectifier diodes (5), (6), (15) and (16), which preferably have an avalanche shut-off characteristic. . 5. Connection according to claims 1 to 4, characterized in that the branches of the secondary winding are each located on separate parts of the first (1) and second (2) primary windings and each of them on its own transformer core post (4), both parts of the primary winding. the windings are connected in parallel to the connection terminals (3) of the primary winding, while the starts of the first sections of the secondary windings (7) and (8) which are located closest to the primary winding are connected to the terminal via the rectifier diodes (15), (16) (12) for feedback and on the other hand via a feedback resistor (11) to ground when the winding ends of the last sections of the two branches of the secondary windings (7), (8) are connected to the output high-voltage outlet via the rectifier diodes (15), (16) (10).