SU1515286A1 - Single-ended self-excited d.c. voltage converter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply and automation systems. The purpose of the invention is to increase efficiency. The single-cycle self-excitation DC / DC converter is made according to a reverse diode circuit on the power transistor 5 and the output transformer 2 and is equipped with a current transformer 4. The power transistor 5 turns off when the current in its power circuit reaches the value of the current of the secondary winding 15 of the current transformer 4 will reach a level sufficient to unlock the auxiliary transistor 14. When the power transistor 5 is closed, the output transformer energy is expended on the load 10 and demagnetizes current transformer 4 by means of a demagnetizing winding 7. Adjustable resistor 17 changes the ratio of currents in the windings of current transformer 4 and thereby adjusts the open state of the power transistor 5, i.e. converter output voltage. 1 hp f-ly, 1 ill.

Description

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3LSI 5286

And the system relates to electrical equipment and can be used in the systems of secondary power supply and automation,

The core of the invention is increased efficiency.

The drawing shows a schematic of a transducer,

The primary winding 1 of the output Yu of the transformer 2 through the primary winding 3 of the current transformer 4 is connected to the collector of the power transistor 5. The secondary winding 6 of the output transformer through the demagnetizing winding 7 of the current transformer and the rectifying diode 8 are connected to the output capacitor 9 and the load 10,

The positive feedback 20 winding 11 of the output transformer is connected via a limiting resistor 12 to the emitter junction of the power transistor, oppositely bounded by a diode 1 3 and the output of the auxiliary: 25 transistor 1A, the emitter junction of the current transformer. The additional winding 16 of the current transformer is connected to the regulated 30 resistor 17, Power to the transducer is supplied to pins 18 and 19,

The Converter operates as follows.

In the presence of supply voltage at 35 pins 18, 19, self-oscillations occur due to the supply of positive feedback voltage from the winding 11 of the start-up transformer through the limiting resistor 12 to the base of the power transistor 5, during the forward run, t, e, during the flow of a linearly increasing collector current. power transistor through the primary winding of 1 output transformer and 45 primary winding of 3 transformers. the current in the output transformer accumulates energy. At the reverse phase, when the power transistor is closed, the energy of the output transformer from the secondary winding 6 through the forward diode 8 and the winding 7. The current transformer enters the output capacitor 9, and the load 10 is energized at both stages of the converter. The winding 7 is for demagnetizing a current transformer during a return stroke.

four

To the current running voltage on the secondary winding 15 of the transformer, the current reaches a value sufficient to open the auxiliary transistor 14, Opening, the auxiliary transistor shuns the emitter junction of the power transistor, reducing its base current. As a result, the power transistor enters a linear mode, on the output windings the transformer reverses the voltage polarity and the converter switches to the reverse mode,

When the resistance of the resistor 17 changes, the voltage on the windings of the current transformer changes. By varying the resistance of this resistor, it is possible to change the threshold value of the collector current of the power transistor, at which the auxiliary transistor opens, i.e., the energy stored in the output transformer during the forward running time and, consequently, the output voltage.

Claims (2)

The duration of the return stroke is determined by the time of energy transfer from the output transformer to the output capacitor and the load. With the exhaustion of the energy of the input transformer due to the EMF arising on its windings, a key-like process of switching to the direct passage takes place in the converter. Invention Formula 1, A single-ended self-excitation DC / DC converter containing an output transformer and a current transformer, the primary windings of which are connected in series and through a power transistor connected to the input terminals of the converter, the secondary winding of the output transformer is connected via a rectifier to the output converter outputs via a rectifier, and the positive feedback feedback winding of the output transformer through the current limiting resistor is connected to the input circuit of the power transistor, untirovannoy auxiliary transistor and the current transformer secondary winding is coupled to the input of the auxiliary transistor, characterized in that, in order povy515152866 efficiency, oppositely parallel to the auxiliary winding, shunted to the power transistor is switched on by the introduced adjustable resistor, the given diode, the indicated connection of the secondary 2. The converter according to claim 1, of the winding of the current transformer, distinguished by the fact that it was completed by means of its direct current transformer made with demagnetization between the base and the emitter-wound winding connected in opposite direction. auxiliary transistor, and subsequently to the secondary circuit, current transformer introduced additional-hanks of the output transformer.