SU554600A1 - Three phase inverter - Google Patents

Description

(54) THREE-PHASE INVERTER

In order to simplify the device, the secondary windings of the pulse transformers are connected between the corresponding terminals of the non-transitory current of the tyrnstorny and reverse bridges 3.

FIG. 1 is a schematic diagram of the proposed inverter; in fig. 2 - voltage and current diagrams in the circuit of the proposed inverter are given, illustrating its operation, where Il - Ie are current thyristor control current pulses, power thyristor nanri switching pulses, are the voltage pulses at the inverter output; in fig. 3 is a schematic diagram of an inverter with a series connection of the arms.

The proposed inverter (Fig. 1) contains thyristors 1-6, semiconductor uncontrolled gates 7-12, capacitors 13, 14, generator 15 of rectangular commutation impulses and pulse transformers 16-18. The load is connected between the midpoint of the capacitor connection and the output of the thyristor bridge.

In the initial state, all thyristors are turned on and the voltages between point O and the outputs of bridge A, B, and C are zero. Capacitors 13, 14 are charged up to a voltage equal to half the supply voltage.

At the time point ti, a pulse and a control current are fed to the control electrode circuit of thyristor 1. Turning it on causes a square voltage pulse Ua. (Fig. 2) at output A.

At time t from the generator 15 rectangular pulses of the voltage through the pulse transformer 16 to the circuit between the output of the thyristor bridge A and the input of the uncontrolled bridge A is supplied a rectangular pulse f / Ki-. 16, a phase A load, a capacitor 14, a semiconductor valve 10. When the amplitude of the voltage pulse t / Ki is greater than the voltage of the power source, a reverse voltage sufficient for the thyristor 1 will be applied to the thyristor 1 go off. During the switching of the current of the thyristor 1, the energy in the load will come from a pulse generator.

At a time / g, a control current pulse is applied to the control electrode circuit of thyristor 2. It is turned on to provide a voltage pulse of reverse polarity 6c to output B. The thyristor 2 is also turned off by a square pulse (7k2 reverse polarity at the moment of time). In this case, the shutdown process proceeds in the same way as the thyristor 1 is turned off.

At the time tz, the control current pulse Iz is supplied to the control electrode circuit of thyristor 3. Its switching on ensures the supply of a square voltage pulse t / c to the output of phase C. Switching off

TymerStore 3 is carried out by a UK pulse, at time tz.

At time t, a control current pulse is applied to the control electrode circuit.

thyristor 4, the inclusion of which provides the supply of a voltage pulse f / a of reverse polarity to the output of phase A.

When performing multi-phase high-voltage DC inverters, a series connection of individual single-phase cells 13 is used. FIG. Figure 3 shows the principle of the proposed inverter with the series connection of individual single-phase cells and a common generator of rectangular voltage pulses. In contrast to the described version of the converter with parallel connection of cells, it contains three single-phase transformers for power take-off and is supplemented by

four capacitors. At the same time, the converter contains one common generator of voltage pulses of rectangular shape for different potential cells, which makes it possible to simplify its circuit.

The generator of rectangular voltage pulses for turning off the power thyristors of the inverter during its operation can be performed on the basis of a parallel inverter according to the author's certificate No. 172394 on the thyristors of the TB series.

The inclusion of the secondary windings of the pulse transformers between the output of the thyristor bridge of the inverter and the input of the uncontrolled bridge allows reducing their nominal

power and eliminates the magnetization of the core. At the same time, the valves of the uncontrolled bridge ensure the return of the reactive load power to the power supply circuit and supply voltage pulses to lock

power thyristors, which reduces the total number of gates in the converter.

Claims (3)

1. A. Krogeris et al. “Semiconductor converters of electrical energy, M., "Energie, 1969, pp. 143-154, pp. 156- 158. 2. M.E. Golts et al. “Automated DC electric drives with 5 pulsed converters, Moscow, Energia, 1972, p. 33, fig. 2-12b (prototype). S 3. USSR author's certificate № 276235 M. Kl. NM 5/42, 1969. A lf. P  . Ua i2 i is n ± “-. D- i nn D ir J e Rig.Z