SU124517A1 - Dc to ac converter - Google Patents

Description

DC-to-AC sinewave converters made on semiconductor triodes, operating in key mode with an open state equal to half the switching period, are known. The proposed converter differs from the known converters of this kind in that it is composed of several single-phase or three-phase converters controlled by current pulses shifted one relative to the other by a predetermined angle, and the sinusoidal output voltage is obtained as a result of the transformation of a multiphase voltage system rectangular in the voltage system with a smaller number of phases, which is achieved by connecting the secondary windings of the output transformers in a zigzag.

This makes it possible to obtain a voltage curve that is close to a sinusoidal shape without changing filters and operating irregularly for the semiconductor triodes, resulting in a lower CTOHMOCTJ converter and simplifies its circuitry.

FIG. 1 shows the electrical circuit of the proposed converter with the inclusion of its triodes according to the bridge circuit; FIG. 2 shows a converter circuit when triodes are turned on according to a midpoint circuit; in fig. 3 is a block diagram of a driver for controlling the converters shown in FIG. 1 and 2.

The converter shown in FIG. 1, consists of two three-phase transducers / and 2, controlled and impulse-voltage, shifted one with respect to the other in phase at an angle of 30 el. Each transducer is made on semiconductor triodes operating in key mode with an opening time equal to half the switching period.

A twelve-phase rectangular voltage system, obtained from transducers n 2, is transformed into a three- or six-phase system with a close to sinusoidal with | shape curve for example, no. 124517 2 -

ki, which is achieved by incorporating the secondary windings of the output transformers 5 and 4 into the zigzag.

The converter shown in FIG. 2, contains six single-phase transducers 6-11, two soil formations 6-8 and 9 form a //. The transducers in each soil are controlled by voltage pulses with a shift of 120 ° e. The shift of the control voltages of both groups is 30 el.

The resulting twelve-phase rectangular voltage system is transformed into a three- or six-phase voltage system, which is close to sinusoidal in shape, by connecting the secondary windings 13-18 of the output transformers into a zigzag.

The multiphase voltages that control the transducers are fed to the windings 5 (Fig. 1) or 12 (Fig. 2) from the multiphase autogenerator or through ring non-singular, or triggering circuits from the single-phase autogenerator.

To simplify the ring scaling scheme by reducing the number of cascades, two ring scaling schemes with half as many cascades in each were used, triggered by 180 ° shifted el. voltage from a trigger controlled by an oscillator.

The driver device (Fig. 3) contains: an auto-oscillator 19, a trigger 20 and .circular ring circuits 2 / and 22.

Subject invention

Claims (2)

1.Dc to sinusoidal alternating current converter made on semiconductor triodes operating in a key mode with an open state duration equal to half of the switching period and controlled by a multiphase voltage system received from a multiphase autogenerator or From a single phase through a ring scaling A circuit characterized in that, in order to simplify the converter and obtain a sinusoidal form of alternating current, regardless of its frequency, the converter is composed of several kih single phase or three phase converters controlled by current pulses that are shifted relative to one another by a predetermined angle, and the secondary winding of said output transformer converters are connected in "zigzag. 2. The converter according to Claim 1, characterized in that, in order to simplify the ring scaling circuit by reducing the number of its stages, two ring scaling circuits are used — with half as many cascades in each, triggered by voltages shifted by 180 electrical degrees. LvWVv- 5 1VWWVW1 I-AVWW 13  I-VWS / VV- | 14 n / VWW-o15 rllm / sixteen Vwvwv1 7 IWWWVH 78 Fig 2 + 4