SU1601720A1 - D.c. to multistage a.c. voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply and electric drive systems. The purpose of the invention is to simplify the device. The converter contains an inverter with a transformer 4, the secondary winding of which has two separate sections. Each section is separated from the midpoint into two equal halves - windings 5.6 and 7.8. The outputs of these windings through the main keys AC 9-14 connected to the output terminals of the Converter. The opposite extreme terminals of the secondary sections of the transformer are connected via additional AC keys 15 and 16. The ratio of the number of turns of the windings 5 (6) and 7 (8) is chosen to be 1: 3. With the appropriate switching algorithm of the primary and secondary switches 9-16 of the alternating current at the load 17, a 9-step voltage (including the zero level) in each half-period can be generated. 2 Il.

Description

Phage. /

I The invention relates to electrical engineering and can be used in systems of secondary power supply and electric drive,

 The purpose of the invention is the simplification of preo- b

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Figure 1 shows the power part of the circuit of the proposed Converter; FIG. 2 shows timing charts that work on

converter

: The converter is connected to a constant voltage source 1 and contains keys 2 and 3 of the inverter, transformer 4, the secondary winding of which is made of two sections. The first section is divided by a branch of the middle point into two halves 5 and 6. The second section is also separated by a tap from the middle point into two half 7 and 8. Conclusions of the first section of the secondary winding through the first group of main currents 9-11 of alternating current connected to the first output terminal of the converter, the terminals of the second section through the second group of primary switches 12-14 of the alternating current are connected to the second output terminal of the converter, and the opposite outputs of the sections are connected by means of additional keys 15 and 16 ac. The keys 9-16 are fully controllable, (control block not shown), the load 17 is connected to the output terminals of the converter.

The ratio of the number of turns of the first section (W 5 + W b) to the number of turns of the second section W 7 + W in is 1: 3. The value of the voltage induced in each of the windings 5 and 6 is equal to Ui, and the induced voltage in each of the windings 7 and 8 is equal to 3 Ui.

Voltage diagrams (Fig. 2), which explain the operation of the circuit, have the following designations: U4 is the voltage on the primary side of the transformer 4 (half-cycle numbers 1-30); Ui7 is a multistage voltage at load 17 (Ui Us is the voltage, respectively, 1–8th levels in the output voltage curve); Ug-Uie are key control voltages 9–16 whose positive level corresponds to the open state of these keys,

The converter works as follows.

in a way.

The zero level in the output voltage curve is generated by shorting the load 17. with keys 11, 12 and 15 or keys 9, 14 and 16.

The windings 5 or 6 of the first section are used to form the first level U i in the output voltage. Winding 5

50

five

connected to load 17 with keys 10, 16 and 14, and winding 6 with keys 10, 12 and 15. The connection order depends on the polarity of the voltage U4 of the transformer and the polarity of the half-cycle of the output voltage of the converter. For example, in the interval (Fig. 2) of the half-period 2 of the voltage U4, the winding 5 is connected to the load by closing (opening) the keys 10.14 and 16. And on the interval of the half-period 3 - the winding 6 by closing the keys 10, 12 and 15.

The second level U2 2 Ui in the output voltage is formed by connecting to the load 17 the entire first section (windings 5 and 6). Such connection is made either by keys 11. 14 and 16, or keys 9, 12 and 15,

To form a third level Uz in the output direction, windings 7 and 8 of the second section are used, which are connected to the load alternately by closing the keys 9, 13 and 16 or the keys 11, 13 and 15. The voltages induced in each of these windings are equal from 3 Ui.

During the formation of the fourth level U4 Ui in the output voltage, the connected in series are connected to the load in accordance with the winding 5 and 8 or the winding 6 and T, respectively, the keys 10 and 13 and 16 or 10, 13 and 15 are closed (Fig.2) .

The voltage level of the fifth level Us 5 Ui is formed from the voltages of the windings 5, 6 and 7 or 5. 6 and 8 by closing the keys 9, 13. 15 or 11, 13. 16. Since these windings are connected in series with this itself and in series with the load, and the ratio of the numbers of turns of these windings is a ratio of 1: 1; 3, then the voltage Us Ui + Ui + 3Ui 5 Ui is formed on the load.

Similarly, the sixth U6, seventh Uy and eighth Us Levels are also formed in the output voltage, with the only difference that only the second section (windings 7 and 8 together) of the second transformer winding is used to form the sixth level. For the formation of the seventh level, the second section and one of the windings are used, either 5. or 6 of the first section, and the entire secondary winding of the transformer is used to form the eighth level. In this case, the values of the voltage levels are respectively equal: ib 6 Ui; UT 7 Ui; Us 8 Ui.

Thus, the proposed converter. Other equal conditions (the number of keys t i, the utilization rate of the transformer secondary winding), allows forming nine levels (including zero) in the output voltage when using a total of eight AC keys.

Claims (1)

Claims of the Inverter DC to multistage alternating voltage containing an inverter with a transformer, the secondary winding of which has two separate sections, each extreme terminal and outlet from the middle 0 the points of each section are connected via a primary AC key to a corresponding output terminal, additional controllable keys and a control unit, so that in order to simplify, two additional AC keys are used, each of which is included between the opposite ends of the secondary sections of the transformer, and the ratio of the number of turns of these sections is equal to 1: 3. one G / Uj t J Г jt / 2 рз t PP n P .n P U13 "% t n n Ppppp Ppppppp ppppppp and. sixteen Ppppp ppppppp A T .n JZLEL n Ppppp Ppppp Fie.2