RU158872U1 - HIGH VOLTAGE AUTONOMOUS INVERTER WITH MULTI-PHASE OUTPUT - Google Patents

Abstract

A high-voltage autonomous inverter with a multiphase output, comprising a voltage divider, made in the form of a chain of capacitors connected in series, which is connected to a constant voltage source, each pair of capacitors of this divider forming a converter cell, the first and second conclusions of which are connected to the primary winding of one of the phases of the output transformer, and the control cell includes controllable key elements and a valve circuit of two series-connected diodes, the common point of which is connected to the midpoint of the capacitor chain, characterized in that the extreme terminals of the capacitor chain are connected, respectively, by the first key element to the first output of the converter cell connected to the anode of the first diode of the valve circuit, the second key element to the second output of the converter cell, to to which, using the third key element, the cathode of the second diode of the valve circuit is connected, the conclusions of the converter cell are connected respectively to one of the extreme and the middle terminals of the primary winding of the output transformer, and the fourth key element is connected between the positive terminal of the voltage divider and the second extreme terminal of the specified primary winding of the output transformer.

Description

“The technical field to which the utility model belongs”

The inventive utility model relates to converters of direct current electric power of increased voltage to alternating current. Such converters are designed for electric locomotives powered by a high voltage direct current contact network (12 or 24 kV), for powerful stationary electric drives with 6-12 kV asynchronous motors, and for special electrophysical equipment.

“BACKGROUND OF THE INVENTION” An inverter is known that contains fully controllable valves and a transformer, the windings of which are turned on in the zero circuit and are connected to a constant voltage source of 20 kV [1] and above by means of these valves.

The efficiency of this inverter is achieved due to the fact that gas-discharge lamps with grid control (developed by EES - USA) are used as valves. They are designed to work in hard-set conditions for temperature, load and overvoltage. Therefore, they are not recommended for use in vehicle on-board converters and other high-reliability installations.

Also known is an autonomous inverter of block execution, containing series-connected converter cells, each of which consists of a capacitor, an inverse-diode connected in parallel to it, and an inverter connected to power transistors connected to them, the outputs of which are connected to the load [2].

The disadvantage of such an inverter is that with a high input voltage, a large number of cells in series are required. This is equivalent to a series connection of power switching elements (usually IGB transistors). It is known [3] that they sharply worsen their characteristics when connected in series. Therefore, now autonomous inverters even for a rated voltage of 3 kV for power and auxiliary circuits of electric locomotives and cars [4] are performed on thyristors. Only at relatively low power (up to 250 kW) are IGBT inverters used [5].

As a prototype, you can take a high-voltage autonomous inverter with a multiphase output, containing a voltage divider, made in the form of a chain of connected in series identical capacitors, which is connected to a constant voltage source, and each pair of capacitors of this divider forms a converter cell, the outputs of which are connected to the primary winding of one from the phases of the output transformer, and the control cell includes controllable key elements and a chain of after ovatelnyh diodes, the midpoint of which is connected to a midpoint capacitors chain [6, 7].

The disadvantage of the prototype is that the key elements included in the cells, i.e. IGB-transistors form a purely sequential circuit, in the breakdown of which there is a dull short circuit (short circuit) of a high-voltage source of constant voltage. There are no current limiting elements in this short circuit and the short circuit current reaches a significant value. This makes the inverter unsuitable for critical systems for fault tolerance.

“Disclosure of a utility model”

The technical result of the claimed utility model is to increase the reliability of the inverter in systems that do not allow power interruptions, for example, in 24 kV DC electric locomotives.

To achieve the above technical result, a high-voltage autonomous inverter with a multiphase output is proposed, comprising a voltage divider made in the form of a chain of capacitors connected in series, which is connected to a constant voltage source, with each pair of capacitors of this divider forming a converter cell, the first and second conclusions of which are connected to the primary winding of one of the phases of the output transformer, and as part of the converter cell, controllable cell elements and a valve circuit of two series-connected diodes, the common point of which is connected to the midpoint of the capacitor chain, while the extreme terminals of the capacitor chain are connected, respectively, by the first key element to the first output of the converter cell connected to the anode of the first diode of the valve circuit, the second key element with the second terminal of the converter cell, to which the cathode of the second valve circuit diode is connected using the third key element, the converter terminals th cell are respectively connected to one of the outer and middle pin of the output transformer primary winding, and a fourth key element connected between the positive terminal of the voltage divider and the second end terminal of said output transformer primary winding.

"Brief Description of the Drawings"

The essence of the utility model is illustrated in the drawings, where:

- FIG. 1 is a circuit diagram of an inverter;

- FIG. 2 is a diagram of the output voltage for one phase.

"Implementation of a utility model"

The inverter contains identical converter cells 1A-1E, which are connected in series and this circuit is connected to a constant voltage source 2 of a magnitude. In detail in FIG. 1 shows a diagram of a cell 1A; it contains capacitors 3 and 4, which are part of the input capacitor voltage divider. There are also diodes 5 and 6; their midpoint is connected to the midpoint of the capacitor circuit 3-4. The extreme points of these chains of capacitors 3-4 and diodes 5-6 are interconnected by key elements (CE) 8 and 9, and the diode 5 is connected to the key element 8 through the key element 15.

A transformer 10 is provided at the output of the converter cell; its primary winding consists of sections 11-12 with an exact average of 13. This point is connected via a key element KE 9 to the input terminal “minus” of the capacitor cell. The extreme points of sections 11-12 of the winding by means of key elements 7 and 8 are connected to the plus terminal of the cell.

To the secondary winding 14 connect consumers of alternating current; the number of phases is determined by the number of cells 1. For example, in the circuit of FIG. 1 shows 6 cells 1A-1E, which allows the formation of a 6-phase voltage or two systems of 3-phase voltages. Accordingly, the windings of transformers 10 can be placed on one 6-phase core or on two standard cores [8, 9].

The principle of phase voltage generation is shown in FIG. 2. Suppose that in the initial state the key elements 7, 8, 9, and 15 are turned off, all capacitors 3-4 are charged from source 2 with a voltage of each, where m is the number of cells 1.

When turned on at the time of the key elements 9 and 15, the voltage of the capacitor 4 is applied to the winding section 11; the current closes along the circuit -5-15-11-9-. At the moment, the key element 8 is turned on and the key element 15 is turned off, as a result of which the total voltage of the capacitors 3-4 will be applied to the winding section 11, i.e. The current closes along the circuit -8-11-9-.

At the moment, turn off the key element 8, disconnecting the capacitor 3 from the power circuit of the winding section 11, and turn on the key element 15. Now this winding is under the voltage of the capacitor 4 (circuit -5-15-11-9- By the time the formation of the positive half-wave voltage in winding 14. At this moment, the key element 9 is turned off and the key element 7 is turned on, forming a circuit -7-12-6-. The current is replaced by a current, the magnetic flux in the core of the transformer 10 changes direction and the formation of a negative half-wave voltage starts in the winding 14. phase A, i.e.

Further, in the process of generating the output voltage curve, the key element 9 is turned on at the moment. The total voltage of the capacitors 3 and 4 will be applied to the winding section 12, i.e., and the current of the section (half-winding) 12 is closed along the circuit 3 ₊ -7-12-9 -. At the moment, the key element 9 is turned off, and the winding section 12 feeds the capacitor 3 along the circuit - 7-12-6-. At the moment, the formation of the negative half-wave ends and the formation of the positive half-wave begins again, for which the key element 7 is turned off and the key elements 9 and 15 are turned on. Next, the half-wave formation is repeated as described above from the moment, i.e. from the beginning of the period.

All cells 1A-1E function identically. Their work differs only in phase shift, which allows the generation of a multiphase output voltage. In FIG. 2 shows the formation of phase voltage in cell 1B with a shift relative to the voltage of cell 1A.

The analysis of the diagrams of FIG. 2 shows that during operation of the inverter, the capacitors 3 and 4 are discharged equally, which is a condition for the normal operation of the capacitor divider.

The advantage of this inverter is that sections 11-12 of the transformer windings are connected in series to the IGB transistor circuit, which eliminates the possibility of through breakdown of this circuit and increases the reliability of the inverter.

Information sources

1. Birnbach K.A. High voltage autonomous inverter. RF patent No. 2473163, cl. Н02М 3/15, op. 01/20/2013, company EES (USA);

2. Malakhov A.P. etc. Frequency-controlled electric drive. RF patent No. 2293432, cl. H2P 25/22, op. 02/10/2007, NSTU;

3. Devices of power electronics of railway rolling stock / V.M. Antyukhin, A.A. Bogomyakov, Yu.A. Evseev et al .; under the editorship of Yu.M. Inkova and F.I. Kovaleva - M .: Federal State Budgetary Educational Establishment "Educational and Methodological Center for Education in Railway Transport", 2011. - 471 p.

4. Electric locomotives EP10, EP20. Technical documentation. Electrical equipment. NEVZ;

5. Yatsuk V.G. High voltage voltage converter for passenger cars. RF patent No. 2403667, cl. H02M 7/5387, op. 06/12/2010;

6. Sinyavsky I.V. DC / DC Converter RF patent No. 2345473, cl. Н02М 3/24, op.27.01.2009, VELNII;

7. Pustovetov M.Yu. Theoretical study of the power supply device auxiliary circuits of an electric locomotive. Electronics and electrical equipment of transport. 2015, No. 1, p. 18-20, fig. one;

8. Vasyutinsky S.B. Questions of theory and calculation of transformers. 1970, 442 p.

9. Khnykov A.V. Theory and calculation of multi-winding transformers. 2003, 141 p.

Claims (1)

A high-voltage autonomous inverter with a multiphase output, comprising a voltage divider, made in the form of a chain of capacitors connected in series, which is connected to a constant voltage source, each pair of capacitors of this divider forming a converter cell, the first and second conclusions of which are connected to the primary winding of one of the phases of the output transformer, and the control cell includes controllable key elements and a valve circuit of two series-connected diodes, the common point of which is connected to the midpoint of the capacitor chain, characterized in that the extreme terminals of the capacitor chain are connected, respectively, by the first key element to the first output of the converter cell connected to the anode of the first diode of the valve circuit, the second key element to the second output of the converter cell, to to which, using the third key element, the cathode of the second diode of the valve circuit is connected, the conclusions of the converter cell are connected respectively to one of the extreme and the middle terminals of the primary winding of the output transformer, and the fourth key element is connected between the positive terminal of the voltage divider and the second extreme terminal of the specified primary winding of the output transformer.

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