SU1198692A1 - D.c.voltage converter - Google Patents

Description

The invention relates to electrical engineering, in particular to power supply devices, and can be used in power supplies of electronic and other equipment.

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

The drawing shows a diagram of the inverter DC voltage.

The converter contains two inverter cells with single-phase transformers 1 and 2, the primary windings of which 3 and 4 are connected via power transistors 5 and 6 to the input power terminals, and the transistor bases are connected to the control circuit 7. The secondary output windings 8, 9 of transformers are connected to the output terminals for the load connections 10. The demagnetization windings 11 and 12 of the transformers are connected in series through the diode 13 and the first transistor 14 and the current-limiting resistor 15 connected in parallel. The windings 16 and 17 of the respective trans formators 1 and 2 are connected to the base-emitter junction of transistor 14 through cut-off diodes 18, 19 and resistor 20. The collectors of transistors 5 and 6 are connected through protective diodes 21 and 22 to capacitor 23 and choke 24, the second end of choke 24 is connected to collectors of transistors 25 and 26 , and their emitters are connected to the collectors of the respective controlled transistors 5 and 6.

The Converter operates as follows.

The firing control pulses from the control circuit 7 are fed alternately to transistors 6 and 25 and 5 and 26.

The process of magnetization reversal of the transformer core 2 (reversal of the transformer core 1 corresponds to the symbols in brackets). When unlocking the transistor 5 (6), the winding 3 (4) of the transformer 1 (2) flows around the current. In this case, winding 8 (9) transfers energy to the load.

198692 2

10, and the winding 11 (12) carries out the reversal of the transformer core 2 (1) due to the series circuit formed by the coils 11 and 12, the diode 13 and the transistor 14 parallel with the resistor 15 connected in parallel. streamlined so

10 as the transistor 14 is open (its base-emitter junction by the winding 17 (16) of transformer 2 (I) is shifted in forward

direction). If the core of the transformer 2 (1) becomes saturated,

15 then the induced EMF in the winding 17 (16) will become 0, the transistor 14 will turn off, and the resistor 15 will limit the current in the circuit to a predetermined level.

. Capacitor 23 with diodes 21 and 22

20 to transistors 25 and 26 provide a push-pull mode of the converter and its protection from overvoltages. So when the transistor 5 is locked, the energy determined by the inductive dissipation of the transformer 1 windings through the circuit plus the power source — the winding 3 — diode 21 — capacitor 23 — minus the power source — enters the capacitor 23.

30 At the same time, the voltage at the closed transistor 5 is limited at the level υ = 2Ε + 4ϋ (\. After unlocking the transistor 6, the energy caused by the voltage increment on the capacitor 4 and _s > returns to the load along the circuit: capacitor 23 choke 24 - transistor 25 - winding 3 and 4 — transistor 6 is the minus of the source.At the same time, the magnetization reversal of the core of the transformer 1 is carried out, and the process proceeds as previously described.

Thus, the magnetization reversal of the transformer core is carried out without limiting the magnetization reversal current until the core is saturated and the current is then limited after the core is saturated. This allowed us to reduce the energy losses in the current-limiting resistor and to force the magnetization reversal process.

1198692

Claims (1)

CONSTANT VOLTAGE CONVERTER, containing two single-phase inverter cells connected in parallel at the input and output, in power transistors with corresponding transformers, the output windings of which through diodes are connected to the output terminals, and demagnetization windings are connected in series with each other through a diode and a current limiting resistor, characterized in that, in order to increase efficiency and reliability, it is equipped with three transistors, four diodes, two transformer windings, a choke and a capacitor, with the first transistor inserted connected in parallel with the current limiting resistor and its control transition through a resistor is connected to two parallel chains. Each of them consists of a series-connected transformer winding and a compartment ayuschego diode, and the output electrodes of power transistors are respectively connected to the first electrodes of additional transistors and the protection diodes, wherein the combined second electrodes of additional transistors are connected via a throttle to the second electrodes of the protective diodes connected in turn to a supply terminal via a capacitor. 5II ,, P98692 > eleven