SU1356150A1 - A.c.to bipolar d.c.voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used to power devices that require two different DC voltages. The purpose of the invention is to increase efficiency and reliability. The voltages at the output terminals 12,13,14 are equal in magnitude and have the corresponding polarity during the entire rectification period. In the event of a short circuit of the load, a resonance mode occurs, protecting the source from the current limit. As complex impedances 3,4,5,6 can be used capacitances, inductances, in particular the windings of the transformer and the phase windings of the induction motor: l. 2 hp ff, 8 ill. Iffnf П СО СП О5 01 о and FIG. shl,

Description

The invention relates to electrical engineering and can be used for powering devices that require two different polarized voltages.

The purpose of the invention is to increase efficiency and reliability.

Fig. 1 is a diagram of a variable-voltage-to-constant two-pole voltage converter; Fig. 2 shows voltage and current graphs explaining the operation of the converter; Figures 3-6 are embodiments of a converter circuit; 7.8 shows the equivalent circuits (alternating current) for the transducer loads made as shown in FIG. 5.6, respectively.

The AC-DC to DC converter contains two input pins 1 and 2, four complex resistances 3-6, a single-phase bridge rectifier 7 containing diodes 8-J1, three output pins 12-14. The first input pin 1 is connected to the first output pin 12 First complex impedance 3 and the second impedance 4 with one pin connected to the second input pin 2, and the other to the diagonal of the alternating current rectifier 7 and to the corresponding pins J5, 16 of the third 5 and fourth 6 complex resistances, free terminals of complex resistances 5,6 are combined and connected to the first input terminal 1. In this case, complex resistances 3-6 are equal respectively:

U

and

-i; to and

to D

 -ke

1-k 1. k + 1 i

KZ

where nd, 1 - complexes acting

the values respectively of the voltage of the single-phase power source and the short-circuit current of the converter;

K - some constant (), the ratio of the output voltage to the input voltage.

FIG. 3 is a diagram of an embodiment of the converter, the image of FIG. 1, in which complex resistances 3-5 are made in the form of tanks 17-19, and complex resistance 6 are in the form of first phases.

five

0 5

0

0

five

0

five

asynchronous capacitor motor 21, the second phase winding 22, which is connected between the input cables 1 and 2.

Fig. 4 shows a diagram of an embodiment of the converter shown in Fig. 1-5 in which the impedances 3.5 are made respectively in the form of the first 20 and second 22 phase windings of an induction motor 21, the impedance 4 is in the form of inductance 23, and the impedance 6 is made in the form of capacitance 24.

On. Fig. 5 is a diagram of the embodiment of the converter transformer shown in Fig. 1, in which the complex resistances of the SZD are designed as primary 25 and secondary windings 26, transformer 27, impedance 4 in the form of capacitance 28, and impedance 6 is equal to infinity ( missing),

FIG. 6 shows a diagram of a variant of the converter shown in FIG. 1, in which the impedances 4.5 are made in the form of primary 25 and secondary 26 windings of the transformer 27, respectively, the impedance 3 is in the form of capacitance 29, and the impedance 6 is infinite (missing ),

The AC-to-constant-bipolar voltage converter (Fig. 1) operates as follows.

In the absence of a load 30 connected between pins 12,13 and a load 31 connected between pins 14,13, the current i (t) flowing through the complex, resistance 3,4, is out of phase by an angle / 2 the alternating voltage U (t ) U sinwt of the alternating voltage source connected to the input terminals 1 and 2, and the current ijCt), flowing through the complex resistances 5 and 6 lags the voltage U (t) in phase by an angle of 7/2 (FIG. 2 a, d ).

When the converter is in operation in the first half period F, the potential is output 0, and the output potential is tj 0. Diodes 8.9 will be opened accordingly. In this half period, the voltage between output terminal 13 and output circuit 12 is equal to v (t) 7/0 (Figure 2e), and the voltage between output terminal 14

313

and the output terminal 12 is equal to k (t) O (Fig. 2g).

In the next half-period, the output potential is positive, and the output potential is positive. Accordingly, diodes 10 and 1 will be open. In this half-period, the voltage between output terminal 3 and output terminal 12 is c / (t) O, and the voltage between output terminal 14 and output terminal 12 is (/ (t): r 0 .

T

. Thus, the converter performs a two-pole push-pull rectification and the voltages on the output pins of the converter are equal in modulus and have a corresponding polarity during the entire rectifier period.

With a short circuit load, Ie in case of short circuit of resistors 30 and 31, short-circuiting of complex resistances 3 and 5 occurs. At the same time, TOK.i (t) from the source of alternating voltage flows through parallel-connected complex resistances 4 and 6, which form a parallel resonant circuit. A current resonance mode and a total current i (t) 0 occur in the circuit. Thus, in the converter, the influence of the limiting operation mode (short circuit of loads on the alternating voltage source) is excluded.

Converter (fig.Z) works as follows.

When an alternating single-phase voltage is applied to the input terminals 1 and along the windings 20 and 22, the currents are shifted in phase. The role of phase shifting

l-

element performs capacity 19, When

This rotor of the electric motor 21 comes into rotation. If it is necessary to cool the diodes 8-11 during operation, the fan for blowing the diodes 8-11 can serve as the load for the electric motor 21. In this case, the two-stroke two-pole rectification process takes place in a manner similar to that in the converter shown in FIG. 1.

The converter shown in FIG. 1 works in a similar way.

The converter in FIG. 5 operates as follows.

When an alternating single-phase voltage is applied to the input terminals 1 and 2, the primary winding of the transformer and the capacitor carries a current lagging in phase by an angle of 71/2. The voltage on the primary winding 25 will be in phase

561

5, O

-

20 -30

35

40

504.

with input voltage. The secondary winding 26 of the transformer 27 creates an anti-phase voltage at terminal 16. An additional advantage of this circuit is the equalization of voltages at the output terminals and under asymmetrical loads (Fig. 7).

Timing diagrams of this scheme coincide with those shown in figure 2,

The converter (FIG. 6) works in the same way. Its additional advantage is the higher rigidity of the output characteristic (Fig. 8).

Claims (1)

Invention Formula I, AC to DC bi-voltage converter, containing two input terminals, the first of which is also the first output terminal, four complex resistances, the first and second of them are connected to the second input terminal by one and the other to the diagonal of the variable input. the current of the single-phase bridge rectifier and to the corresponding conclusions of the third and fourth complex resistances, the free conclusions of which are combined, the diagonal of the direct current of the bridge single-phase top of the grid forms the second The first and third output terminals, characterized in that, in order to increase efficiency and reliability, the combined terminals of the third and fourth complex resistances are connected to the first input terminal, with the first, second, third and fourth complex resistances being respectively: and and K and K and -KZ tk 1; 1.7 - operating complexes values, respectively, of the voltage of the single-phase power source and the short-circuit current of the converter; - some constant (), the ratio of the output voltage to the input voltage. The creator according to claim 1, about the t and iy with the fact that the first, fourth complex accompanied in the form of tanks, complex resistance made in the form of a first phase winding of an asynchronous single-phase capacitor motor, the second phase winding of which is connected between the input terminals. 3. The converter according to claim 1, o t - li. because the third and the fourth impedance is made in the form of the primary and secondary windings of the transformer connected in opposite, the second impedance is infinity, and the first impedance is in the form of capacitance. ABOUT dofilo) 6/4 / Ojt fig.Z FIG. and yy “R (pufS Srig.T Editor N.Slobod nickname FL dzie.8 Compiled by E.Melnikova Tehred L. Serdyukova Proofreader L. Pilipenko FL dzie.8 Order 5807/51 Circulation 659 Subscription VNSHPI State Committee of the USSR for inventions and discoveries 113035, Moscow, 4/5, Raushsk nab. Production and printing company, Uzhgorod, Projecto st., 4