SU847466A1 - Self-sustained voltage inverter - Google Patents

Description

The invention relates to power static power converters and can be used in electric power installations of various purposes for converting direct current into alternating current.

A single-phase inverter is known, which contains a DC source, the positive pole of which is connected to the DC output of the converter cell on the thyristors through a separation thyristor, and a forced switching node connected to the separation thyristor

A voltage inverter is also known, which contains a thyristor separator at the pole of the converter cell and a switching node 2j.

The disadvantages of these devices are their complexity and the poor shape of the output voltage curve.

A self-contained voltage inverter is known that contains a converter cell on the thyristors, a thyristor switching switching node and separation thyristors, the input terminals of the inverter are connected to the alternating current terminals of the converter cell, the output terminals are connected to the DC outputs through the separation thyristors, and the forced switching node connected to the DC terminals of the converter cell (31.

However, such an inverter produces a rectangular voltage that differs from a sinus voltage. Improving the sinusoidal voltage of the output voltage requires the use of filters, which complicates the inverter.

The purpose of the invention is to improve the output voltage curve and simplify.

The goal is achieved by the fact that an autonomous voltage inverter containing a converter cell on the thyristors, a thyristor forced switching node and separation thyristors.

the output pins of the inverter are connected to the AC output pins of the converter cell, the input pins are connected to the DC terminals through the separation thyristors, and the forced switching node is connected to the DC terminals of the converter cell, provided with additional pins for connecting the intermediate terminals of the power supply, connected through additional separation thyristors with the corresponding DC outputs of the converter cell.

At the same time, the forced switching node is made in the form of a sequential chain formed by a charge thyristor, a throttle and a switching capacitor, and the charge thyristor and a choke are shunted in the opposite direction by a switching thyristor.

Figure 1 is a schematic diagram of a single-phase bridge inverter; Fig. 2 shows timing diagrams of the control voltage and anode current of the power, separation and switching thyristors, as well as the voltage on the load, constructed for the case of a purely active load. The inverter contains main thyristors 1-4 separation thyristors 5 and 6, a DC power supply 7 consisting of two sections, switching node 8 consisting of thyristor charge 9 and throttle 10, switching capacitor I1 and switching thyristor 12. Thyristors 1- 4 shuntiroan1 1 reverse diodes 13-16. AC load 17 is included in the bridge AC diagonal. Additional separation thyristors 18 and 19 are connected between additional input terminal 20 and thyristors 1-4. The inverter works as follows. At time point b (figure 2), the control voltage of the inverter produces control voltage pulses% m. SR-5 unlocking thyristors 1.4, b and 19. As a result, the voltage of one source section is applied to load 17 7 DC power supply. On the time interval t –t in the load 17 and through the thyristors 1,4,5 and 19, a current flows, the value of which is determined by

Claims (3)

the voltage of one section of source 7, At time fc, control voltage pulses are produced, Uvfnp.g 5 unlocking thyristors 6 and 9, as a result of which a full source voltage 7 is applied to load 17. In the time interval in load 17 and in the thyristors 1,4,5 and 6 a current flows, which is determined by the total voltage of source 7, and on the same time interval, the capacitor I1 is charged, which is charged through choke 10 to a voltage approximately equal to double voltage load 17, At time t, you take with momentum control voltage Ujjnp ji thyristor 12, whereby to thyristors 5 and 6 is applied reverse voltage. In the time interval, the thyristors 5 and 6 are turned off, and the capacitor 11 is discharged along the circuit formed by the thyristors 1 and 4 and the load 17. At the time point L as a result of the discharge of the capacitor 11, the thyristors 1,4 and 12 turn off, and at the same time with this, control voltage pulses are generated, -jij, VnpiS .jg unlocking so-christores 1,4,5 and 19, as a result of which the voltage of one source section 7 is applied to the load 17. In the time interval t, -t5 in the load 17 and the thyristors 1,4,5 and 19 current flows, which is determined by the voltage One section of the source 7, and at the same time the charge of the capacitor II occurs up to a voltage approximately equal to the double voltage of the source section 7. At time-fcg, a voltage pulse Uvjnp Q, is produced, which triggers the thyristor 12, resulting in a thyristor 5 and 19, a reverse voltage is applied. In the time interval (, the thyristors 5 and 19 are turned off, and the capacitor 11 is discharged along the circuit formed by thyristors 1 and 4 and the load 17. After the discharge of the capacitor 11 is completed, the thyristors 1.4 and 12 turn off. In the future, the electrical processes in the inverter repeat similarly described (see, figure 2, moments of time. t. - ifo. In addition, figure 2 gives egor of currents on thyristors 1-6 and 18.19, as well as on load 17 (; if, 5 19 ft H The difference in the flow of electrical processes in the inverter during the formation of the reverse half-wave of alternating voltage for It includes that a reverse polarity voltage is applied to the load 17, i.e. the other pair of main thyristors 2 and 3 is working, and also the dp of ensuring uniform loading of the sections of the DC power supply 7 is changed to the reverse order of connecting the sections source, which is achieved by joint operation with main thyristors 2 and 3 and switching thyristors 5 and 6 of additional thyristor 1. The diagrams given in Fig. 2 refer to the case of a purely active load, i.e. to the case when the curves of the change in current and voltage repeat each other. In the event that the load is inductive in nature, the curves of change in current are somewhat different from those shown in the diagram (Fig. 2), however, the nature of the change in voltage across the load remains unchanged. Since the curve of the output voltage of the inverter has a two-step form, the spectral composition of the curve is. The output voltage is improved, and the design of the filters is simplified. In a number of cases, the inverter can be made without filters. Claim 1. An autonomous voltage inverter containing a converter cell on the thyristors, a thyristor forced switching node and separation thyristors, the inverter input terminals being connected to the AC converter terminals, output terminals connected to the DC terminals through the separation thyristors the forced switching node is connected to the DC terminals of the converter cell, characterized in that, in order to improve the output voltage curve and control circuit formulas It is provided with additional input pins for connecting the intermediate terminals of the power source, connected via additional isolation thyristors with the corresponding DC terminals of the converter cell, 2. POP1 inverter, characterized in that the forced switching node is designed as a serial chain formed A thyristor, a choke and a switching capacitor, and the thyristor and a choke are protected in the opposite direction by the switching thyristor. Sources of information taken into account during the examination 1. Japan, No. 52-27337, l. H 02 M 7/515, published. 1977. 2. The patent of Switzerland No. 518645, l. H 02 M 7/48, 1970. 3. For Japan No. 51-12815, l. H 02 M 7/515, published 1976.