SU1422341A1 - D.c. to three-phase stepped quasisine voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and m. used in secondary power systems. The goal is to reduce the weight and size and increase the QDC. The device contains a single-phase inverter 1 and an output transformer 2, the magnetic core of which is composed of three closed cores whose magnetic cores have a rectangular hysteresis loop with different coercive forces. As a result of alternating reversal of the cores 3-4-5 in the secondary windings 7,10,13-8,11,14-9,12,15, an emf is induced. When the number of turns of the windings is 7.9, 11-14, and the number of turns of the secondary windings 8, 11,, 15, equal to 2 °, three: quasi-sinusoidal voltages are shifted out of phase by 120 at the device output. 2 Il. (L Yu Yu 00 41k. / A

Description

(DUZ.1

i The invention relates to electrical engineering and can be used in secondary power supply systems and electric drives to convert a constant voltage to a three-phase quasi-sinusoidal voltage.

The purpose of the invention is to reduce the weight and size and ejection of efficiency.

FIG. 1 shows a diagram of a pre-converter converter; 2, time diagrams of the voltages, where and, are on the primary winding of the transformer; Ug, U {j, U - transformer. Forms of output voltage, respectively, in phase a, b, c).

The converter (Fig. 1) contains a single-phase inverter 1 and an output transformer 2, the magnetic circuit of which is recruited from three closed (toroidal) cores. The materials of the cores 3-5 are rectangular, the shape of the hysteresis loop, respectively, with the coercive magnet motive force FCJ The primary winding b covers all cores. The secondary windings 7–9 are included in phase a, the windings 10–12 are in phase b, phase c is windings 13–15, respectively, laid on cores 3 - j5 and connected in series, i The device operates as follows.

; When the polarity of voltage Bd changes (moment of time t) applied to the primary winding 6, core 3 begins to re-magnetize; transformer 2, cores 4 and 5 will not be re-magnetized, since the magneto-motive force F generated by the primary winding 6, is equal to the magnetomotive force F, and is insufficient for their magnetization reversal. After the complete reversal of the core 3 at the time t, the magnetically moving force F of the primary winding 6 increases abruptly to. The magnitude F and the layers 4 begin to oscillate. winding 6 t ,, T, / 2) when the voltage of the reverse polarity on the primary winding 6 occurs, a sequential magnetization reversal of the cores 3 - 5 in the opposite direction in the same sequence 3-4-5. c. As a result of alternating magnetic reversal of the cores 3-4-5 in the secondary windings 7,10,13-8,11,14-9,12,15 an emf is induced. So for the scheme of switching on the secondary windings in phases a, b, c

0 (fig, 1) when the number of turns of the windings 7, 9,11-14 is equal to W and the number of turns of the windings 8, 11, 15 is equal to 2W, three quasi-sinusoidal voltages Ua ,, are formed at the output of the converter

5 c (fig. 2), shifted among themselves by the oo phase by 120. The harmonic composition of the voltages Up, V, U. is the number of turns and the wiring scheme in the phases of the secondary windings,

In this case, the magnetization reversal of individual layers and their number in the core of the transformer.

In the proposed device, the weight and dimensions are reduced, and the PCC is reduced due to the elimination of the bias windings.

Claims (1)

Invention Formula A constant voltage converter into a three-phase, step-like quasi-sinusoidal voltage containing a single-phase inverter with a rectangular output voltage, the output of which is connected to the primary winding of the output transformer, the magnetic circuit of which has alternating peremagnetized pits where the secondary windings are different. that, in order to reduce weight and dimensions and increase efficiency, the mentioned sections of the output transformer magnetic circuit are made in the form of closed ikov, covered by a common primary winding, and the number of cores is a multiple of three and is equal to the number of equal duration intervals stepwise modulation of the i half period the output voltage, and the coercive forces of the core materials are different from each other to provide alternating magnetization of the cores. FIG. 2