SU1617565A1 - Single-end d.c. voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply systems. The purpose of the invention is to reduce the weight and size. The power transistor 1 periodically switches the power supply circuit of the Drossel 5 to which the primary winding 7 of the power transformer 2 is connected through an additional diode 3, which is bridged by an additional capacitor 9. When the power transistor 1 is turned off, the reactive energy stored in the choke 5 is transmitted to and from the power transistor 2 secondary winding 8-in load. An additional capacitor 9 demagnetizes the core of the power transformer 2 and ensures a decrease in the voltage rise rate when the power transistor 1 is turned off and thereby reducing the dynamic power loss in it. 2 hp f-ly, 2 ill.

Description

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

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

Fig. 1 shows the electrical circuit of the proposed converter: Fig. 2 is a variant of its implementation.

The single-ended DC-DC converter (Fig. 1) contains a switch power transistor 1, a power transformer 2, an additional diode 3, a rectifying diode 4, an inductor 5, a filter capacitor 6. The winding of the chokes 5 is connected to the beginning of the primary winding 7 of the power transformer 2 and to the first input terminal of the converter. The second terminal of the winding of the choke 5 is connected to the anode of the diode 3 and through the power transistor 1 is connected to the second input terminal of the converter. The cathode of diode 3 is connected to the output of the primary winding 7 of the power transformer 2, the beginning of the secondary winding 8 of the power transformer 2 is connected to one output of the capacitor 6, the end of the secondary winding 8 of the power transformer 2 is connected to the anode of the rectifying diode 4, the cathode of which is connected to another output of the capacitor 6 .

.In parallel to the primary winding 7 of the power transformer 2, an additional capacitor 9 is connected.

The single-ended DC converter works in the following manner.

When the positive voltage pulse applied to the base of the switching transistor 1 turns on the switching transistor 1, the current in the choke 5. begins to increase. During the open state of the switching transistor 1, energy is accumulated in the inductor 5. When the voltage pulse at the base of the switching transistor 1 becomes zero, the switching transistor 1 is turned off. Due to the self-induced EMF arising on choke 5, diode 3 opens and current flows through the primary winding 7 of the power transformer 2. A voltage pulse opens on the secondary winding 8 of the power transformer 2, which opens the rectifying diode 4. and part of the energy accumulated in the choke 5 in the previous step, it is transmitted to the capacitor 6 and the load. At this stage, the throttle current 5 drops, and the core of the power transformer 2 is magnetized in the forward direction. At the same stage, the charge of the additionally introduced capacitor 9, which reduces the rate of voltage rise at the closing of the switching transistor 1, occurs,

At the time of the next switching on of the switching transistor 1 due to the EMF of self-induction appearing on the primary winding 7 of the power transformer 2, the diode 3 is kept open, and the demagnetizing proceeds through the primary winding 7 of the power transformer 2

10 current, respectively, along the contour; 7-1-3-7. In this case, the demagnetization current of the core of the power transformer 2 is directed opposite to the collector current of the switching transistor 1. At the same stage, under the action of

The 15 self-induced EMF arising on the primary winding 7 of the power transformer 2 recharges the additional capacitor 9. In addition, energy is accumulated in the choke 5. When the pulse voltage at the base of the switching transistor 1 becomes zero, the recharge of the additional capacitor begins 9. The recharge current of the capacitor 9 increases in proportion to the current of the switching transistor 1. As the capacitor 9 recharges, the voltage across it increases slowly, and therefore the dynamic cic loss during shutdown

0 of the switching transistor 1 and the rate of increase of the voltage across it are reduced.

Further, all the processes in the converter are repeated.

5B, in the two-transistor version, the proposed converter (FIG. 2) additionally contains a power transistor 10 and two recovery diodes 11 and 12, the Transistors 1 and 10 are controlled synchronously and in phase. The converter works in the same way as described. The recovery diodes return the excess energy of the throttles to the power source, limiting the overvoltage on the power transistors.

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Claims (3)

1. Single-ended converter: a constant-voltage converter, containing a switch for connecting drossel to the converter's input terminals, a power transformer, the primary winding of which is connected to the output terminal of the Drossel by the first terminal, and the secondary winding through a rectifying diode 5 is connected to the output terminals of the converter, shunted filter capacitor, additional capacitor and additional diode, characterized in that, in order to reduce the weight and size, the additional capacitor is connected in parallel flax primary winding of a power transformer, a second terminal of which is connected via a further diode to the second terminal of the choke. 2, the Converter according to claim 1, from the L and h and yu and the fact that the switch is made in the form of a single power transistor connecting one of the leads to the first input terminal of the converter, and the second terminal of the connecting cable is connected to the second input terminal converter directly. + o 3. Converter pop. 1, differing from the fact that the switch is made in the form of two power transistors and two recovery diodes, with the first output of the throttle through the first power transistor connected to the first input terminal of the converter and through the first recuperative the diode is connected to the second input terminal of the converter, and the second terminal of the throttle is connected via the second power transistor to the second input terminal of the converter and through the second recovery diode to the first input terminal of the converter. FIG. 2