SU862334A1 - Current regulator - Google Patents

Description

(54) SINGLE-PHASE VOLTAGE CONVERTER

I

This invention relates to the field of electrical engineering and can be used as a single-phase to three-phase voltage converter.

A single-phase-to-three-phase voltage converter is known, which is the prototype of the invention and contains a phase-split bridge, in two adjacent arms of which a capacitor and a resistor are connected, and decoupling amplifiers at output 1.

The deviation of the actual parameters of the phase-splitting bridge from the calculated ones causes the amplitude and phase errors of the output voltage. The first is easily eliminated by adjusting the gain of the decoupling amplifiers, but phase error remains. For this reason, the three-phase voltage at the output of the converter is not symmetrical, i.e. There is no exact conversion.

The aim of the invention is to improve the conversion accuracy by reducing the phase error of the output voltage.

This goal is achieved by the fact that in a single-phase voltage converter

THREE-PHASE

a three-phase bridge containing a phase-splitting bridge, in two adjacent arms of which a capacitor and a resistor are connected, and isolating amplifiers at the output, used one inverting and two non-inverting decoupling amplifiers and introduced three additional resistors, one of which is included in the third shoulder of the phase-splitting bridge and the other two are connected in series and included in the fourth shoulder, with the common connection point for additional resistors of the fourth shoulder

10 and their outermost terminals are connected to the output terminals via inverting and non-inverting decoupling amplifiers, respectively.

FIG. 1 shows a functional 15 converter circuit; in fig. 2a, b, are its vector diagrams constructed for two possible cases of phase error; in fig. Za, b, c - vector diagrams constructed for three possible cases.

20

Claims (1)

The converter contains a phase-separation bridge formed by a capacitor 1 and resistors 2-5. The ends of resistors 4 and 5 and their common point are connected to the output terminals through non-inverting 6 and 7 and inverting 8 isolation switches. The input voltage is supplied to the points A, E of the bridge, the common point of resistors 4 and 5 is denoted by the letter D, and the common point of resistors 2 and 3 is O and is grounded. B is the connection point of resistor 5 and capacitor 1. The values of the resistances of the bridge elements are chosen in the ratio,. The operation of the transducer is visible from the vector diagrams of FIG. 2a, b, at which the ends of the A, B, C, D, E vectors correspond to the potentials of the nodes of the circuit of FIG. 1, denoted by these letters. The vectors A, B, Cd, C, correspond to the ideal case, when there is no phase error, the vectors A, B, C, D, - to the real case. From the diagrams it follows that for both cases the phase error of the vector C Af, to the phase error of the vector B, determined by the error of the circuit consisting of capacitor 1 and resistors 4 and 5. The symmetry of the output voltage can be estimated by the method of symmetric components, this, the error of this converter is much less than the phase error of the prototype. Claims of the Invention A single-phase voltage converter to a three-phase one containing a phase-splitting bridge, in two adjacent arms of which a capacitor and a resistor are included, and isolating amplifiers at the output, characterized in that, in order to increase accuracy, one inverter and two non-inverting isolating amplifiers are used and three additional resistors were introduced, one of which is connected to the third shoulder of the phase-splitting bridge, and the other two are connected in series and included in the fourth shoulder, with the common connection point no additional shoulder fourth resistors and their extreme terminals connected to the output terminals through the non-inverting and inverting amplifiers respectively decoupling. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 253224, cl. H 02 M 5/02, 1969 (prototype). at, but ff A-A, f1 /. but ff f VSJ ff t h BO f at