SU1198706A1 - Twelve-phase non-symmetric compensated a.c.voltage-to- d.c.voltage converter - Google Patents

Description

The invention allows to increase the efficiency and reduce the level of higher harmonics at the input and output of the twelve-phase unbalanced compensated converter of alternating voltage due to the fact that the third 4 and fourth 5 are three-phase, connected windings connected to each other in transformer 1. They are connected to the corresponding inputs of the second pair of rectifier bridges 8, the outputs of which are connected to the output terminals 17, 18 through a two-phase reactor 12 and a three-phase compensating device Line 10 is similar to the first pair of rectifier bridges.

The result is a complete balancing of the current converter. Between the bridges in pairs 7 and 8, the currents are aligned with reactors 11 and 12, and between the pairs of bridges alignment is provided by saturation throttles 13. Full symmetry allows the entire converter to be brought to the maximum possible value of the rectifier current. Due to one-sided switching on of compensating devices and one-sided throttle control, the conversion mode is approaching twenty-four phase. 5p.p.f-ly, 2 ill.

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1198706

The invention relates to a power converter technology and can be used to power graphite rovers and ore-smelting furnaces, electrolysis series and other energy-intensive consumers of direct current.

The purpose of the invention is to increase the efficiency and reduce the level of higher harmonics at the input and output of the converter.

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Fig. 1 shows a twelve-phase unbalanced compensated AC-to-DC converter with the inclusion of saturation throttles in both pairs of rectifier bridges when their control windings are connected in series and connected to the windings of saturation of both bridges to independent DC sources; figure 2 - diagram of the Converter with chokes saturation, included only in the first pair of rectifier bridges.

The converter (Fig. D) contains a transformer 1 with a switching device supplied with a mains winding 2 in each phase, as well as the first 3, second 4, third 5 and fourth 6 valve windings connected to the first 7 and second 8 pairs of rectifier diode bridges, the first 9 'and second 10 three-phase compensating devices in the form of three-phase reactors, shunted by three-phase capacitor banks, the first 11 and second 12 two-phase balancing reactors and saturation throttles 13 with a working winding 14, a control winding 15 and a winding see scheniya 16 and output terminals 17 and 18, between which and the respective pairs of rectifier bridge outputs are included biphasic equalizing reactors 11, 12 and compensating devices 9, 10.

In each rectifier bridge, the working windings 14 of chokes 13 are connected between the point of connection of the corresponding phase of the valve winding with the power electrode of the cathode group valve and the corresponding power electrode of the anode group of the rectifier bridge, and the control winding 15 and the bias winding 16 are connected to terminals 19-24 for connecting sources direct current.

In the device of figure 2 are missing. in the second pair of bridges, saturation throttles with working windings, as well as control and bias windings.

The operation of the Converter is as follows.

When transformer I is connected to the mains by a winding 2, a twelve-phase voltage system is formed on the valve windings 3,4,5 and 6, the rectification of which by the first 7 and second 8 pairs of rectifier bridges creates a constant voltage on the output terminals 17 and 18 of the converter. With the help of compensating devices 9 and 10, ensuring the operation of the associated valves in the artificial switching mode, the reactive power consumed by the converter from the mains is compensated. Two-phase equalization reactors 11 and 12 ensure the normal operation of the valves connected to them in the natural switching mode, as well as the equalization of the rectified current between the rectifier bridges inside each. from pairs of bridges 8 and 7. Due to one-sided throttle control and one-sided activation of compensating devices 9 and 10 into pairs of rectifier bridges 7 and 8, the current load of transformer 1 decreases depending on the capacitor capacitance and throttle control depth by an amount in the range of 0- 15%, with the same amount of rectified current. Due to the fact that the rectifier bridges and reactors are amplified by the current by the same amount, without exceeding the normal current load of the transformer for which it is designed, the rectified current of the converter can be increased by an amount lying in the range of 0-15%, which allows significantly intensify the process. Regulation of the rectifier voltage switching taps from the power winding 2 of the transformer 1 and using saturation throttles 13. In addition, using throttle saturation 13 with working windings 14, control windings 15 and the bias windings 16 align the currents between pairs of bridges 7 and 8. This is provided either by turning on saturation throttles in just one pair of bridges, or

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supplying throttles of saturation of bridge pairs 7 and 8 from independent regulated DC sources., or specifying the difference in bias currents in windings 16 or control in windings 15 in throttles of the pairs of bridges proportional to the unbalance current of bridge pairs 7 and 8. As a result, full balancing is provided current transducer (between bridges in pairs 7 and 8 currents are aligned with reactors 11 and 12, and between pairs of bridges alignment is provided by saturation throttles). Full symmetry allows you to bring the entire converter to the maximum possible value of the rectifier current, which, along with the specified increase in the rectifier current due to one-sided switching on of the compensating devices and control, additionally allows you to increase the efficiency of the process. The presence of two additional valve windings 5 and 6 for the transformer 1 and an additional pair of bridges 8 reduces the level of higher harmonics in the mains current and the rectified voltage of the converter. At the same time, due to one-sided switching on of compensating devices and one-sided throttle control, the conversion mode is approaching twenty-four phase.

Claims (6)

Claim 1. Twelve-phase unbalanced compensated AC / DC converter containing a transformer with one three-phase mains winding equipped with a switching device in each phase, as well as first and second three-phase switched winding windings connected to one another, each of which is connected to the input of one of the two rectifier bridges forming the first pair, and between the first output pin and the common points of connection of the same power electrodes of the anode valves The bridges are connected to a two-phase surge reactor, and a three-phase compensating device, made in the form of a three-phase reactor, shunted by a three-phase capacitor battery, as well as saturation throttles, a working winding of each of them are connected between the second output terminal and the common connection points of the cathode groups of these bridges which are connected between the point of connection of the corresponding phase of the valve winding with the power electrode of the valve of the cathode group and the corresponding power The electrode rod of the anode group is rectifying) 0 th bridge, and the control and bias windings are connected to adjustable DC sources, in order to increase efficiency and reduce the level of higher harmonics at the input and output of the converter, the transformer is additionally equipped with the third and fourth three-phase other winding windings connected opposite to each other, connected to the corresponding inputs of the additionally introduced second pair of rectifier bridges, the output of which is connected to the first and the second output terminals che25 Res additionally entered the reactor and the three-phase two-phase compensating device similarly to the first pair of rectifier bridges, and the number of parallel valves each · 30 valve shoulder of the first and second pairs of rectifier bridges, as well as the cross section of the windings of two-phase and three-phase reactors and converter busbars are larger compared to the nominal „Value by value in range 0-15%. I 2. The transducer of claim 1 of tlichayuschiysya in that the second pair of additional rectifying bridge ⁴⁰ is provided with a saturation Tel'nykh chokes operating winding and the control winding and the displacement of each of which are incorporated similarly windings throttles saturation of the first pair of issue 45 funnel bridges. 3, the Converter according to claim 2, denounced by the fact that the control windings of the throttles of saturation of the second pair of rectifier bridges co5 ° are united in series with the similar windings of saturation throttles of the first pair of rectifier bridges and are connected to a common regulated DC source, and the windings 55 displacements of saturation throttles of the indicated pairs of bridges are connected to independent regulated DC sources, the difference of the currents of which < five . 1198706 6 ryh proportional to the current unbalance of the first and second pairs of rectifier bridges. 4. The converter according to claim 2, which is τι in that the bias windings of the saturation throttles of the second pair of rectifier bridges are connected in series with the similar windings of the saturation throttles of the first pair of rectifier bridges and are connected to a common adjustable . the direct current source, and the control windings of the throttles of saturation of the indicated bridge pairs are connected to independent regulated DC sources, the difference of the currents of which is proportional to the unbalance current of the first and second pairs of rectifier bridges. 5. The transducer of claim 1, about _5: Leech in that the first and second three-phase transformer windings counter valve connected in the forward and reverse triangles, and the third and similar melting chetver10 winding connected in forward and reverse star. 6. The converter according to claim 1, in that the first and second three-phase opposing ventilating windings of the transformer are connected into forward and reverse stars, and the analogous third and fourth windings are connected into forward and reverse squares.