RU1800567C - D c/d c converter - Google Patents

Abstract

Usage: DC voltage conversion in secondary power supply systems. The essence of the invention: the control unit 19 generates control pulses of transistor switches 1,2,7 and 8. During the time when the keys 1, 2 are open and the keys 7, 8 are closed, a linearly increasing winding current 5 of the cross-link 6 flows through the load 24 transformed through windings 3 and 12 of transformer 4, and a linearly decreasing current of winding 22 of throttle 11. For another half period, when keys 7, 8 are open and keys 1, 2 are closed, a linearly increasing winding current of 10 throttle 11 flows simultaneously through load 24 transformable through windings 9 and 13 ransformatora 4 and linearly decaying current windings 20 throttles 6. The load current 24 has a small pulsation due to the difference in rate of rise and fall of current in the windings drosseley.2 yl. .. C..K.D. 7 (L

Description

The invention relates to electrical engineering and can be used in secondary power supply systems of various electronic equipment.

The purpose of the invention is to reduce ripple, increase efficiency and improve the overall dimensions of the converter.

In FIG. 1 is an electrical diagram of the proposed DC / DC converter; in FIG. 2 are timing diagrams explaining the operation of the game.

The DC / DC converter contains a first power circuit including transistor switches 1 and 2 (the number of transistor switches connected in series is selected so as to ensure the optimal voltage mode of each switch), the first primary winding 3 of transformer 4 is connected in series with it and the primary winding 5 throttle 6, and the second power circuit, including transistor switches 7 and 8 and sequentially connected to the second primary winding 9 of the transformer 4 through the primary winding 10 dross 11. The secondary windings 12 and 13 of the transformer 4 are connected via diodes 14 and 15 to the output terminals 16 and 17, between which a filter capacitor 18 is connected. The output terminals of the control unit 19 are connected to the control terminals of the transistor switches 1, 2, 7 and 8. The secondary winding 20 of the throttle 6 through the diode 21 and the secondary winding 22 of the throttle 11 through the diode 23 are connected to the output terminals 16 and 17, respectively. Position 24 in FIG. 1 indicates the inverter load.

The converter operates as follows.

The control unit 19, to which the signals of the current and voltage sensors can be supplied via the feedback loop, generates control pulses for the transistor switches 1, 2, 7, and 8.

It should be noted that the greatest positive effect during the operation of the device is achieved when the following conditions are met:

 L / 22 W12 Wio W3

Wis 2 Quich

Wg

UB

where W2o and Ws - the number of turns of the windings 20 and 5 throttle 11;

W22 and Wio - the number of turns of the windings 22 and 10 throttle 11;

Wg. Wi2, Wia and WG - the number of turns of the windings 9, 12, 13 and 3 of the transformer 4;

L / s and UBX values of the output and input (supply) voltage of the converter.

When conditions (1) are met, the next

5, the control pulses Ui, 2 and Uy.a (Fig. 2) at the time ti put the transistor switches 1 and 2 into the open state, and the keys 7 and 8 into the closed state, as a result of which the transformer winding 3 to the circuit

10 4 - winding 5 throttle 6 voltage UBX is applied, which is divided equally between said windings.

Starting from the moment ti in the circuit o. winding 3 of transformer 4 and winding 5 throttle 6

15, a linearly increasing current flows, 5, 5, and in the winding circuit 12 of the transformer 4, a linearly increasing current ii2. At the same time, a linearly decreasing current 122 flows in the winding circuit 22 of the throttle 11, the speed

20 which, when conditions (1) are satisfied, is equal to the slew rate of the current H2. Since the load current i24 over time is equal to the sum of the currents ii2 and I22, then, as can be seen from the diagram in FIG. 2, the value

25 current 24 for a specified time will be constant.

At time point 2, the control pulses Lh, 2 and U, 8 of block 19 put the transistor switches 1, 2 into the closed state, and

30 transistor switches 7, 8 are in the open state. At the same time, processes similar to those that took place over the course of time occur in the device’s circuit, with the difference being linear

35 increasing points flow in the winding 9 circuit of transformer 4 - winding 10 throttle 11 (current 1d, s) and in the winding circuit 13 of transformer 4 (current From), and a linearly decreasing current - in the winding circuit 20 throttle 5

40 (current i2o). The load current 124 over time is also constant in magnitude, since it is equal to the sum of the currents I and i20.

At time tz, the transistor switches 1, 2 open again, and the transistor switches 7, 8 are closed and the process is repeated, providing a direct current flow in the load circuit 24.

The converter operation mode considered above, as already noted, is possible only if conditions (1) are satisfied, since in this case the relation also holds:

(2) where tH and tc are the rise and fall times of the current

55 in throttle x 6 and 11.

In cases where conditions (1) are not fulfilled, a different relation is obtained, obtained from the condition that the power accumulated and transferred to a load of 24 power in one load by interrogators 6 and 11 is equal;

tc tH + tn, (3)

where tn is the pause time corresponding to the closed state of all transistor switches.

In FIG. 2 such a mode is shown, starting from the point in time. Consider the processes that occur in the transducer upon fulfillment, conditions (3).

Over the course of ts-te time, transistor switches 1 and 2 are open and a linearly increasing current 3 flows through winding 3 of transformer 4 and winding 5 of throttle 6, a linearly increasing current Ii2 flows through winding 12 of transformer 4, and 11 throttle through winding 22 is the linearly decreasing current yi. In this case, the load current 24 increases slightly according to the linear law, since the rate of rise of current h2 is greater than the rate of decrease of current rg and, therefore, complete mutual compensation of changes in these currents does not occur.

At time te, transistor switches 1 and 2 are closed, and until moment rt all transistor switches are closed. At this time, linearly decreasing currents flow to the load 24 of the winding 20 of the throttle 6 (current l2o) and the windings 22 of the throttle 11 (current 22). As can be seen from FIG. 2, this leads to the appearance of a small ripple of the current (24.

At time t, the transistor switches 7 and 8 open and over time a linearly increasing current 19.10 flows through the winding 9 of the transformer 4 and the winding 10 of the throttle 11. through the winding 13 of the transformer 4 - a linearly increasing current From, and through the winding 20 throttle 6 - a linearly decreasing current iao. The load current also increases slightly, and at the time te, when the transistor switches 7 and 8 are closed, it decreases again.

At time tg, the transistor switches 1 and 2 open again and the process continues in a similar manner.

Thus, in the proposed converter in comparison with the prototype device, mutual compensation of changes in the currents of double-wound chokes and a transformer is carried out. When conditions (1) are satisfied,

almost complete compensation for these changes, that is, obtaining the greatest positive effect. In cases where conditions (1) are not satisfied, there is an incomplete compensation for changes in these currents, which leads to some increase in the ripple of the output current.

In general, the proposed converter provides a sharp decrease in output current and voltage ripples in comparison with all known devices, an increase in efficiency due to a decrease in power losses in the power in the filtering capacitor, and an improvement in weight and size indicators due to the use of a smaller filtering capacitor.

Claims (1)

SUMMARY OF THE INVENTION A DC / DC converter comprising two power circuits connected between its input terminals, each of which includes at least one transistor switch, a transformer, the first primary winding of which is connected in series to the first power circuit, and the first secondary winding through the first diode is connected to the output terminals of the converter, between which a capacitor is connected, as well as the first two-winding inductor, the primary winding of which is connected in series to the first power circuit A circuit and a control unit, the output terminals of which are connected to the control terminals of transistor switches, characterized in that, in order to increase efficiency and improve overall dimensions, a second double-winding inductor is introduced into it, and the transformer is equipped with second primary and secondary windings the first of which is connected in series to the second power circuit through the primary winding of the introduced second double-winding throttle, and the second through the second diode is connected to the output terminals of the converter, while the secondary ki first and second two winding chokes introduced through the third and fourth diodes respectively connected to output terminals of the converter. "7.6 t t t-5 t5