SU377945A1 - BRIDGE TRANSISTOR CONVERTER WITH TRANSFORMER BACKPRESSURAL FEEDBACK ON CURRENT - Google Patents

Description

The invention relates to the field of converter technology and can be used in power supply systems with low-voltage primary sources.

Known bridge transformer converters with transformerless current feedback, designed to convert a constant voltage of one level into a higher voltage constant, are push-pull with a zero output transformer. Therefore, such converters have increased dimensions and weight.

Reducing the size and weight of the output transformer and increasing its efficiency It is provided by performing the converter according to the bridge circuit and connecting the transformer windings in the following way.

The opposite ends of the secondary windings and the first electrodes of the two diodes are connected to the bases of the transistors, the collectors of which are connected to the primary input terminal, the other ends of the secondary windings are connected to the bases of the transistors whose emitters are connected to the second input terminal of the power supply, and to the additional windings, the second ends of which are connected with the first electrodes of the other two diodes, with the load connected at one end to the common junction point of the second electrodes

all four diodes, and the other end to the first input terminal.

A variant of the circuit of the proposed converter with pnp type transistors is shown in the drawing.

The converter contains a transformer / s primary 2, two secondary 3 and 4, two additional windings 5, 6.

The primary winding 2 of transformer 1 is included in the diagonal of the bridge formed by transistors 7, 8, 9, 10. The common point of the transistors 7, 8 is connected to the "zero, and the common point of the transistors 9, 10 to the minus of the power source 11. The base of the transistors 9, 10 are connected to the anodes of the diodes 12, 13 with the ends of the secondary windings 3, 4 of the transformer /. The base transistors 7, 8 are connected to the ends of the secondary 3, 4 and additional 5, 6 windings. The anodes of the diodes 14, 15 are connected to the other ends of the additional windings. The cathodes of the diodes 12, 13, 14, 15 form a common point to which the load end 16 is connected. The other end of the load 16 is connected to the "minus of the power source 11.

The scheme works as follows. If the transistors 7, 9 are open, the voltage of the power source // is applied to the primary winding 2 of the transformer / and the emf is balanced. this winding. Polarity emf secondary windings are such that transistors

7 and 9 are maintained in the open, and transistors 8 and W in the closed state. The base current of the transistor 7 flows through the following circuit: “source plus 11, transition emitter-base of transistor 7, transformer secondary winding 4 /, diode 13, load 16,“ source minus //. A blocking voltage equal to the sum of the emf induced in the secondary 4 and an additional 6 windings is applied to the diode 15.

The base current of the transistor 9 flows through this circuit: the emitter-base transition of the transistor I is secondary 3 and the additional 5 transformer windings /, diode 14, load 16, source /), the emitter-collector transition of transistor 7, the primary winding 2 of the transformer /. Diode 12 is locked with a voltage equal to the sum of the emf induced in the secondary 3 and an additional 5 windings.

Considering the circuit paths of the base currents, we can conclude that the load current is the sum of the base currents of the transistors 7 and 5.

Under the action of the voltage applied to the primary winding 2 of transformer 1, its core is re-magnetized. At the moment of saturation of the core, the magnetizing current of transformer 1 rises sharply. Due to the growth of the collector current, transistors 7 and 5 go out of saturation state. The voltage drop on them grows, as a result of which the emf decreases. the windings of the transformer 1, and, consequently, the base currents of the transistors 7 and 9. The collector currents of the transistors 7 and 5 are reduced, emf. the transformer windings change sign, the transistors 7 and 5 are closed, the transistors 8, 10 are opened. Next, the processes in the circuit are repeated.

From the analysis of the operation of the circuit, it can be seen that the load 16 produces a constant voltage, equal in magnitude to the sum of the voltage of the power source and the voltage induced in the secondary winding. When using transistors, the polarity of switching on the power supply and 12-If diodes is reversed.

Subject invention

Claims (3)

1. Bridge transistor converter with transformerless feedback on a current containing four diodes and an output transformer with a primary winding included in the diagonal of a bridge of four transistors, two secondary and two additional windings, characterized in that in order to reduce the size and weight and increase the efficiency. the opposite ends of these secondary windings and the first electrodes of the two diodes are connected to the bases of the transistors, the collectors of which are connected to the primary input terminal, the other ends of the secondary windings are connected to the bases of the transistors whose emitters are connected to the second input terminal of the power source, and to the additional windings, the other ends of which connected to the nerve electrodes of the other two diodes, with the load connected at one end to the common connection point of the second electrodes of all four diodes, and at the other end to the first th input terminal. 2. A converter according to Claim 1, characterized in that when using transistors of pp-p type, the first electrode of the diodes is the anode and the second is the cathode, the first input terminal being negative, and the second is zero. 3. A converter according to Claim 1, characterized in that when using pn-type transistors, the first electrode of the diodes is the cathode and the second is the anode, the first input terminal being positive, and the second negative.