SU1229926A1 - Versions of three-phase a.c.voltage-to-d.c.voltage converter - Google Patents

Abstract

The invention relates to power supply devices with a transformerless input for electrical and radio equipment. The purpose of the invention is to improve the energy performance. The converter contains valves 1-6, forming the anodic and cathodic groups, and double-throttle inductors 7-9. One of the pins of the valve A9 d lei 2, 4, 6 of the first group is connected to the opposite terminals of the valves 1, 3, 5 of the second group and to the input terminals. The other terminals of the valves 2, 4, 6 are combined and form the first output terminal 18. The free terminals of the valves 1, 3, 5 are connected to the first windings 11-13 chokes 7-9. The free output of the first winding of each drossel is connected to one output of the second winding of the throttle of the adjacent phase when they are sequentially turned on. The free leads of the second windings 14–16 of the chokes are combined and form the second output pin 17. The use of double-winding chokes and their specified connection provide the operation mode in which the remagnetization of the chokes occurs almost along the symmetrical hysteresis loop. Due to this, the energy characteristics are improved. 2 sec. the item of f-ly, 4 ill. 9 C l / V V xz th co Stock 1C 05 FIG. f

Description

The invention relates to converter equipment and can be used in power supply devices with a transformerless input of electrical and radio equipment.

The purpose of the invention is to improve the energy performance.

FIG. Figures 1 and 2 show variants of converter electric circuits; in fig. 3 and 4 - electromagnetic processes in the main circuit elements.

FIG. and 2 A, B, C are input terminals of the converter for connection to a three-phase alternating voltage source. Valves 1-6 form the anode (first) valve group and the cathode (second) valve group.

Double-wound chokes 7–9, load 10 and valves 1–6 in the first (Fig. 1) and second (Fig. 2) variants are connected as follows.

Each of the first windings 11 -13 chokes 7-9 is connected in series with one of the second windings 14-16 of the adjacent phase, for example, winding 11 of phase A with winding 16 of phase C, winding 12 of phase B with winding 14 of phase A, winding 13 phase C - with winding 15 phase B.

The initial leads (indicated by the Yuki of the first windings 11-13 are connected respectively to the cathodes of the valves 1, 3, 5 (Fig. 1), to the cathodes of the valves 4, 6, 2 (Fig. 2).

The initial terminals of the second windings 14-16 are connected to a common point forming the output terminal 17 of the converter (Fig. 1) with the anodes of the valves I, 3, 5, respectively, whose common point of cathodes forms the output terminal 17 (Fig. 2).

FIG. 3 shows, RC, c - linear voltages at the input of the converter; Ua, Us, Uc - voltages at the initial terminals a, b, from windings 11-13 relative to output terminal 18; U (, I (Hi "- voltages and currents of windings 1 1 -16 throttles 7-9; Uio, Uo - curve of rectified voltage and. Its average value at the load 10; 1" 8 - equivalent current of magnetization of throttles 8, equal to the algebraic sum of the currents of the windings 12 and 15.

FIG. 4 illustrates npoi; ecc re-magnetization of chokes 7-9 during one period of the input voltage across the hysteresis loop; B, H - induction and voltage - a field in the magnetic circuit; the ti-t points characterize the magnetic states of the magnetic conductor at the end of each time interval l / 3 in accordance with FIG. 3

The processes in the converter of FIG. 1 and 2 are identical; therefore, we consider the operation in the time interval of one input voltage period, for example, UCA. in FIG. 1. The cycle of magnetization reversal of chokes 7–9 will be analyzed by the example of one throttle 8.

At the time t ti, the voltage UCA passes through a zero value, and the voltage UAB becomes equal to the voltage UCB (Fig. 3a). From this point in time and up to t t2, as in the previous time interval, valves 1, 5, 6 are open, the current in load 10 is equal to the sum of the currents flowing through the valves 1, 5 and the windings connected in series with them, respectively, 11 and 16, 13 and 15 (Fig. Ze, h). Since the current ii5 through the winding is 15 droplets 8 at the time t t | reaches a maximum value of 0, and through the winding 12 it is equal to zero (Fig. 3b, 3), the throttle magnetic circuit 8 has a maximum bias, characterized by a point ti on the hysteresis loop (Fig. 4).

On the windings 11 and 16 of the chokes 7 and 9, the voltage drops (Fig. 36, d):

Un + U, 6 UAB-U, o (1)

The voltage Uu is transformed into a winding 14 by a plus on the initial output, and the voltage Ui6 is transformed into a winding 13 by a plus on the final output.

Since valves 1 and 5 are open, the voltage UAC is balanced by the voltage drop across all series-connected windings in the circuit with respect to this voltage:

5 UAc Un + U, 3 + Ui5 + U, 6 (2)

Then from (1) and (2) in accordance with FIG. For, b, g:

U, + U, 3 + U, 5 (3)

From (1) and (3) follows:

U, o UAB-Ui, -U, + U, 3 + ° + and, 6 (4)

The voltage curve Uio at load 10 in accordance with the nature of the change in input voltages UAB, UCB, UAC, voltage drops Un, Uia, Uis, Uie and in accordance with expression (4) has a falling character from the maximum to the minimum (Fig. RE) .

A current of 1 | 5, decreasing in magnitude,

flowed in the winding 15 from the final output

to the initial, so the operating point on

0 hysteresis loop moves from ti to t2

(Fig. 4).

At the time t t2, the voltage UBC passes through a zero value, and the voltage UAC becomes equal to the voltage UAB (Fig. 3a). The valves 5 and 6 are closed, and the valves 2 and 3 are opened when the valve 1 is open. The current through the series-connected windings 13 and 15 is interrupted, and through the windings 12 and 14 increases from zero (Fig. Зж, з). Moreover, in the Q 12 winding, the current flows from the initial output to the final, which is equivalent to a change in the voltage of the current Iis. The operating point on the hysteresis loop of the throttles 8 moves from iz to is, as the current Ii2 increases from zero (Fig. 4).

5 In a switching circuit consisting of windings 11, 12, 14 and 16 chokes 7-9 with respect to the input voltage UAB, both windings 11 and 14 of the chokes are connected in series through open valves 1 and 3. Through the windings 11 and 14 flow currents of opposite direction (Fig. Ze, g). The total inductance of throttles 7 increases abruptly, which causes a spasmodic increase in voltage Un and Ui4. Ha in windings 11 and 14 (Fig. 36, t t2). Since the voltage UAB is equal to the voltage UAC (Fig. 36), on the windings 12 and 16 of the chokes 8 and 9 the voltage drop abruptly decreases by the same amount as on the windings 11 and 14 the voltage drop increases (Fig. Sv, d).

In the time interval, valves 1-3 are open. The voltage across windings II, 12, 14, and 16 decreases as the input voltage UAB, balancing them in this time interval, decreases to the value of Um to zero (Fig. B, c, d). For

contours with respect to input voltages UAC and UBC, the equality is valid:

and, on IDS-II, II, B IVS + and, 2 + + and, 4. (5)

Since the input voltage i.dv change / o / o

in the range of Urn UAB at U, and the input voltage UBC increases from zero to the value of U ™ (Fig. 3a), then

the voltage across the load increases from a minimum value to a maximum (fig., rear). The current in load 10 is equal to the sum of the currents li and Ii2 (Fig. Ze, g).

At time t ta, the voltage of the UAB becomes zero, and the voltage URC reaches the voltage UAC-Gates 1-3 remain open. In the circuit with respect to the input terminals A and B, the voltage of the UAB changed the polarity to the opposite (UBA) and increased from zero to Um, therefore on the windings 11, 12, 14 and 16 the voltage drops also changed polarity and increased from zero to some intermediate (Fig. 36, c, d, 1h t t4). The current in the load 10 is also determined by the total current 111 and Ii2 (Fig. Ze, g).

The magnetic state of the throttle magnetic circuit 8 is determined in the same way as in the previous time interval, by the current Ii2 through the winding 12. As the current Iis is zero and the current If2 continues to increase, the operating point of induction of the throttle 8 moves from ta to some intermediate point t4 (Fig. 4). Since the voltage UBC

varies in range of um

(fig. Sv), and the voltage UAC decreases

F

from value to zero with increasing voltage drops Un, Ui2, UM and U | 6, then the voltage Uio on the load 10

It has a falling character from the maximum to the minimum value (fig. rear).

At the time t 14, the voltage UAC goes through a zero value, and the voltage wA-DETAILES the voltage values UBC. Therefore, valves 1 and 2 are closed, and valves 4 and 5 are opened when valve 3 is open. Current through serially connected windings II and 16 interrupted, and through the windings 13 and 15, the current increases from zero (Fig. Ze, 3). Now the current in load 10 is determined by the currents 1: 2 and bz.

In the circuit consisting of windings 12-15 and their open valves 3 and 5 relative to the input voltage UBC. the windings 12 and 15 of the throttles 8 are connected in a consistent manner. The total inductance of chokes 8 increases in a jump-like manner, which causes a jump-like increase in the voltage drop Ui2 and Uin (Fig. Sv) and a decrease in the voltage drop

0 Ui3 and Ui4 on the windings 13 and 14 of the chokes 7 and 9 (Fig. 36, d).

The magnetic state of the throttles 8 is determined by the algebraic sum of the magnetizing forces of both windings 12 and 15 and currents Ii2 and 1 | 5 flowing in opposite

5 directions relative to the initial conclusions. In this case, since the increasing current Ii2 is much larger than the current L3, the operating point of induction of the throttle - 8 moves from t4 to ts (Fig. 4).

In the circuit relative to the terminals B and C

 the voltage UBC decreases by magnitude

2Um to zero, so the voltage Ui2,

Ui3, Ui4 and Ui5 on the windings 12-15 also

reduced to zero (Fig. 36,

c, d) UBA input voltage

5 varies slightly - | -Um UBA

-u-Urrj (fig. Sv), and the voltage UCA increases from zero to Um- therefore with decreasing values of the voltage drop on the windings 12-15, the voltage Uio on the load increases from minimum to maximum 5 maximum value (fig. rear,).

At the time t ts, the voltage UBC becomes zero (Fig. 3A), and the voltage UCA reaches the voltage UBA. Gates 3-5 remain open. Q In the circuit relative to the input terminals B and C, the voltage UBC has changed the polarity to the opposite (Uce) and increases

from zero to u ,,,, so on

The windings 12–15 voltages also changed polarity and increase from zero to some intermediate values (Fig. 36, c, d,). The current in the load 10 is equal to the sum of the currents 1: 2 and L3 (Fig. Зж, з).

The magnetic state of the throttles 8 is determined by the algebraic sum of the magnetizing forces of both windings 12 and 15 and currents Ii2 and bz flowing in opposite directions. At the same time, since the current Ii2 decreases from the maximum value to zero, and the current 115 continues to increase (Fig. 3b, 3), the operating point of induction of the throttle 8 moves from 15 to 1b (Fig. 4),

At the moment of time tte (fig. Зж), when the oppositely directed currents Ii2 and Iis of the throttle 8 become equal, the total force is equal to zero and the magnetic state of the throttle 8 will be characterized on the hysteresis loop by the point te (fig. 4).

In accordance with the nature of the change in the voltage UBA and the voltages on the windings 12-15 (Figs. Za, b, a, d), the voltage on the load 10 has a falling character from the maximum value to the minimum value (Fig.).

At time tte, the voltage UBA passes through zero, and the voltage UCB becomes equal to the voltage UCA. Valves 3 and 4 close and valves 1 and 6 open when valve 5 is open. The current through the series-connected windings 12 and 14. is interrupted , and through the windings 11 and 16, the current increases from zero. The current in load 10 is equal to the sum of the currents In and bh. In a circuit consisting of windings 11, 13, 15, 16 and open valves 1 and 5 with respect to the input voltage UCA, windings 13 and 16 of the throttle 9 are connected in series according to. The total inductance of droplets 9 increases in a jump-like manner, which predetermines an increase in the voltage drop Ui3 and Ui6 on its windings 13 and 16 and a decrease by the same amount of voltage Un and Ui5 of chokes 7 and 8 (Fig. 36, c, d, t te).

The magnetic state of the throttles 8 is determined by the magnetizing force of the winding 15 (current L3), since the current is zero. The induction operating point on the hysteresis loop is characterized by the position te (Fig. 4).

In the time interval, valves 1, 5 and 6 are open. The voltage UCA decreases from - | -Um to zero, which means that the voltages on the windings 11, 13, 15 and 16 of the chokes 7-9 also decrease to zero (Fig. 36 ; c, d) In accordance with the nature of the voltage variation UAB and the voltage drop across the windings 11 and 16, the voltage Uio across the load 10 increases from a minimum value to a maximum value (Fig. Back):

and, n UCB - and,., - and, 5 UAB + Uii +

fUi. (6)

() C the condition of the throttles 8 is characterized by the movement of the operating point. induction on the hysteresis loop from te to t (Fig. 4).

Further, the processes in the circuit are repeated.

From the above analysis of the processes, it follows that chokes 7–9 are equivalent in the mode of operation of the chokes of alternating voltage, in which the reversal occurs in a nearly symmetric hysteresis loop because: a) there is no constant component of the magnetizing current since the currents through the windings are equal largest and flow in opposite directions relative to the beginning (end) of the windings; b) the amplitude values of the positive and negative half-waves of the equivalent alternating magnetizing current differ by no more than 10%.

The theoretical analysis of the electromagnetic processes in the circuit and the results of the experiment show that, for example, for the time interval in accordance with the voltage and current diagrams of FIG. 36 and cyclical reversal of chokes in FIG. 4, while neglecting the voltage drops on the valves 1-6, the ratios of the voltages on the windings of the chokes 7-9 are as follows (in instantaneous values):

, 6

, e

U ,, 6

(7)

From (2) with regard to (7) for instantaneous values. Research institutes at ti t tg: ° UAc 3U, 6 (8)

for amplitude values at t t2:

and

16 (m)

 4-UAc 4-U "sin60 °

   0,29U ™ (9)

where | bol), it is the amplitude value of the voltage across the choke and the input line voltage, respectively. Voltage at load 10: - the maximum value at t tr in accordance with FIG. 36-d:

UlO (MaKc) 2

-minimal value at t t2 from (1), (7), (9):

and, 0 („„, „UAB - UM - and, e U

1o

0.48U; "

- the average value in the time interval ti t t2 taking into account (3), (7), (9) and the sinusoidal nature of the voltage curves on the windings 13 and 15:

60 ° M

Uo SU "sinadot-f: Unmsinad +

55

+ | -rU, 5.sinada.

12l

 0,708i „.

Claims (2)

1. A three-phase AC-to-DC converter containing two valve groups, some of the terminals of the first group of valves are connected to opposite corresponding terminals of the second group of valves and form input terminals, the other terminals of the first group are combined and form the first output terminal, and free terminals The valves of the second group are connected to the corresponding terminals of the first windings of the chokes, characterized in that, in order to improve the energy characteristics, the chokes are double-wound and wherein the free output of the first winding of each of the inductors is connected to one terminal of a second choke coil in series with the adjacent phase-counter incorporating them, and the free terminal of the second winding inductors are combined to form a second output terminal. 2. A three-phase AC-to-DC converter containing two valve groups, an anode and a cathode, the combined anodes of the anode group forming the first output terminal, and each of the cathodes forms a corresponding input terminal, as well as chokes, characterized in that, in order to improve the energy characteristics, the chokes are double-wound, with the first winding of each of the chokes connected in series with the second winding of the adjacent phase throttles, both of these windings are connected between the cathode of the anode and the anode of the cathode valve group, and the second output terminal is formed combined cathodes of the cathode group.