DE2517118C2 - Feed circuit for a direct current consumer - Google Patents

Description

Mains power. Are depending on the current direction, the thyristors 3a and 3b or 3c and 4a and 4b or 4c in the on state, then the instantaneous value of the load voltage equal to zero, are subject to a positive power current of the thyristor 3a conductive, however, the branches 3b, 3c, 4b, Ac locked , the full DC voltage occurs in the positive direction for the series connection of the two transformer secondary windings, so the load voltage has half the value in relation to a secondary winding. If, on the other hand, branches 3a, 3b, 3c are conductive when the mains current is positive, the direct voltage occurs in the negative direction for the series connection of the two windings, i.e. half the direct voltage in relation to one winding. For clarification, the conductive branches are shown in the following table as a function of the level and polarity of current and voltage. LZ ^ is the DC voltage at the backup capacitor 6.

^ü Ust per
Secondary winding

IL

i - positive not realizable 3 a, 3 b, 3 c
/ = negative 10, 13, 14, 17 4 a, 14, 17

α, 3 b, 15 or 3 a, 16, 3 c 3 a, 16, 15

a, 14, 4 b or 4 a. 4 c, 17 4 a, 4 c, 4 b

12, 11, 16, 15

not feasible

The circuit according to FIG. 2 works analogously, in which the thyristors with the same effect have the same reference numerals as the thyristors in Fig. 1 have and operate in the same way.

1 sheet of drawings

Claims (3)

Claims: it; • Λ.ί 1. Feed circuit for one of a single or multi-phase AC power source through a Transformer-fed direct current consumer with variable current, which has the following characteristics having: - At least two sub-assemblies are provided, each with a voltage wave rectifier with at least two uncontrolled diodes and one in pulsed mode, consisting of at least one forcibly erasable semiconductor valve Contain existing semiconductor controller, which is provided as a compensation semiconductor controller and its output variable composed of a direct component and a sinusoidal component of twice the network frequency is, - a notch filter tuned to twice the mains frequency is provided, - a saturation capacitor is provided, - it is always the one connected to the mains transformer Diode of the full-wave rectifier at least one valve of the semiconductor controller that can be forcibly deleted connected anti-parallel, - There are facilities available by means of which the ignition and extinguishing times of the compulsorily extinguishable Semiconductor valves depending on measured variables, the arrangement of which can be adjusted, according to patent 22 17 023, characterized in that the number of secondary windings (la, \ b) of the transformer (1) is determined by the number of sub-assemblies (5a, 50) that a first connection terminal of each secondary winding is connected to a first alternating current connection . .lme of each sub-assembly is connected, while the second terminal is connected to the second AC terminal of each sub-assembly directly and / or via a partial choke (2a, 2b) of a smoothing device designed as a choke (Fig. 1 and 2) · 2. Feed circuit according to claim 1, characterized in that one sub-assembly (5b) is designed as a four-quadrant controller and a second sub-assembly (5a) is designed as a two-quadrant controller (Fig. 1). 3. Feed circuit according to claim 1, characterized in that both sub-assemblies (5a, 5b) are designed in such a way that the anode of the respective first forced-erasable semiconductor valve (4a or 3a), which the AC connections of each full-wave rectifier (10 to 13 and 14 to 17) of a sub-assembly, via a second automatically erasable semiconductor valve (3c or 4b) with the positive pole and the cathode of the first force erasable semiconductor valve (4a or 3a,} via a third force erasable semiconductor valve (3b or 4c) with the negative pole of the direct current circuit, the connections of one secondary winding (\ a) being connected to the cathodes of the first force-erasable semiconductor valve (4a or 3a) , while the connections of the other secondary winding (\ b) are connected to the anodes of the first force-erasable Semiconductor valves (4a and 3a ^ are connected (F i g. 2). The invention relates to a supply circuit for a direct current consumer according to the preamble of claim 1. From DE-OS 21 59 397 is a so-called _{four-quadrant:} circuit is known which is used when supplying a direct current or direct-voltage load from a single-phase or multi-phase alternating current network, the power factor cos φ should be as close as possible to 1.
It is also known (DE-OS 23 17 0C7) to connect partial arrangements of two-quadrant controllers in series in order to reduce the harmonic content in the alternating current by means of suitable control. Compared to the mentioned prior art, the present invention makes the task of the Reduce the reactive power component of the fundamental oscillation even further and thus the power factor even further closer to the value 1. This object is achieved by the features characterized in claim 1 Advantageous refinements of the invention are characterized in the subclaims The invention is described in more detail using two exemplary embodiments.
It shows F i g. 1 shows a circuit arrangement in which a four-quadrant controller is interconnected with a two-quadrant regulator, 2 shows a circuit arrangement with two identical ones Partial arrangements. In the two figures, parts that are the same or have the same effect are provided with the same reference symbols. On the primary side 1 of a transformer (not shown) AC power supplies AC power in the two secondary windings la, ib. The terminals of these two secondary windings la, Ιό are connected to the AC terminals of sub-arrays 5a, 5b, wherein the first terminals of the two secondary windings on part chokes 2a, 2b, each connected to a first alternating current connection of the subassembly 5a and 5b , while the second connection of the two secondary windings are each led to the second alternating current connection of the two subassemblies 5a, 5b . The sub-arrangement 5a consists of a full-wave rectifier, which consists of four diodes 10-13 arranged in a bridge circuit, the alternating current connections of which can be bridged by two forced-erasable semiconductor valves 3a, 4a connected in anti-parallel to one another. The direct current outputs of the full wave rectifier 10-13 are connected to the plus or minus pole of the direct current circuit, which consists of a direct current consumer 9 to which a backup capacitor 6 and a harmonic filter 7, 8 are connected in parallel. The sub-arrangement 5a designed as a two-quadrant converter is connected in parallel on the DC side to the sub-arrangement 5b, designed as a four-quadrant converter, which is formed from a full-wave rectifier which is connected in a bridge with the aid of the diodes 14-17, with each diode 14, 15, 16, 17 having a forced-erasable semiconductor valve 3c or 4c or 4b or 3b is connected in antiparallel. The arrangement according to FIG. 1 works as follows:
If all thyristor branches are blocked, then each secondary winding is connected to the DC voltage side via the associated chokes and diodes, the instantaneous value of the load voltage, viewed from a secondary winding, has the same level as the DC voltage and the same polarity as the