SU788300A1 - Dc-to-dc converter - Google Patents

Description

The invention relates to electrical engineering and can be used to build voltage or current regulators and static converters.

Known converters on magnetotransistor switches with positive current feedback, in which the current transformer operates at a frequency equal to the output frequency of the Converter in General p /.

However, at a low output frequency, the current transformer has a large weight and dimensions, and at a zero output frequency, the converter is inoperative.

Closest to the proposed technical essence of the DC / DC converter based on magnetotransistor switches with a control circuit operating at a frequency different from the output frequency of the converter, and containing a power transistor, the collector circuit of which in series with the load includes the primary windings of two current transformers, secondary the windings of which are included in parallel circuits connected with the control circuit of a bi-transistor [2].

However, the known converter has a rather complex control circuit comprising three transformers and a master oscillator.

The purpose of the invention is to simplify the circuit and reduce losses.

This goal is achieved by the fact that control transistors are introduced into the control circuit of the converter, 10 power circuits of which are connected in series with the secondary windings of the corresponding current transformers, and the common point of these windings is connected to the input terminal.

In FIG. 1 and 2, variants of the converter circuit diagrams are presented.

The converter is built on a power transistor 1, control transistors 2 and 3, controlled by a control device (CU) 4.

The secondary circuits 5 and 6 of current transformers and 8 are included in the output circuits of transistors 2 and control, the primary windings of 9 and 10 of which are included in the output circuit of power transistor 1.

The load 11 is shunted by the diode 3Q 12. The diodes 13 and 14 are shunted primary. 3 windings of 9 and 10 current transformers.

The converter operates as follows.

When the control transistor 2 is unlocked from the control unit 4, the power transistor 1 is unlocked by the current from the power supply 0 _pmT 2 _g, and this current is almost proportional to the collector current of the power transistor 1, which is ensured by the operation of the current transformer 7 in the current limiting mode.

In the current transformer 8, at this time, the collector current of the power transistor 1 demagnetizes the core. Diode 14 serves to limit the voltage on the windings of this current transformer 8.

The voltage limitation on the windings of the current transformer can also be done by connecting additional windings 15 and 16 to the power source through isolation diodes 17 and 18 (Fig. 1) or by connecting diodes 19 and 20 to the secondary windings 5 and 6 of the current transformers 7 and 8 and to the power emitter transistor 1 (Fig. 2).

After turning off the control transistor 2, the control transistor 3 is turned on and the current transformer 8 starts to operate in the current limiting mode, and the core of the current transformer 7 starts to be demagnetized by the load current.

Further operation of the circuit is similar to decommissioned.

The frequency of operation of current transformers -7 and 8 does not depend on the output frequency of the converter and, therefore, in order to reduce the weight and dimensions of current transformers, a very large one (up to

100 and more kHz). In this case, the power transistor 1 is unlocked by a current practically proportional to the current of its collector. Power supplies and _PIT4 and Opt about. (figure 1) can be combined.

In the general case, the primary windings of current transformers can be connected to various loads, and transistors 2 and 3 current transformers 7 and 8 can be used as a source of proportional current for any known type of load (for example, current sensors).

Claims (1)

Claim 15 A DC to DC converter containing a power transistor, in the collector circuit of which the primary windings of two current transformers are connected in series with the load, the secondary windings of which are included in parallel circuits and are connected to the control circuit of the power transistor, which that, in order to simplify the scheme and reduce losses, 25, control transistors are introduced into the control circuit, the power circuits of which are connected in series with the secondary windings of the corresponding current transformers, and the common 30 point of these windings is connected to the input terminal.