SU794698A1 - Transistorized inverter - Google Patents

Description

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The invention relates to the field of electrical engineering and can be used in devices of secondary sources PI-. tani.

The transistor inverter is known to have the disadvantage of not protecting the power amplifier's transistors against over-voltage spikes. The closest technical solution to the invention is an inverter containing a master oscillator, the input ports of which are connected to the input terminals of the inverter, and the output from the push-pull power amplifier with an output transformer, with one of the input terminals of the inverter and the capacitor plate connected to the midpoint of the primary winding of the latter, and the other side of the capacitor dsoedinena through diodes to the extreme terminals of the primary winding of the transformer 2.

This inverter allows you to protect transistors of a power amplifier with a high voltage surge. However he has

reduced efficiency due to the loss of energy in the resistor, which bypasses the capacitor.

The circuit of the invention is increased efficiency.

This is achieved by the fact that in the transistor inverter, which contains the master oscillator, the output pins of which are connected to the input pins of the inverter, and the output is connected to the input of a push-pull power amplifier with the output transformer, one of the input terminals of the inverter and the cover are connected to the center point of the primary winding of the last one. the capacitor, and its other plate is connected via diodes to the extreme terminals of the primary winding of the transformer, the common connection point of the capacitor and the diodes is connected to one of the input terminals of the driver generator, another input output of which is connected to a common point of the primary winding of the output transformer through an additional diode.

The drawing shows a schematic diagram of a transistor inverter.

794668

The inverter contains a master oscillator 1, made on transistors 2 and 3 and switching transformer 4, power amplifier 5, made on transistors 6 and 7 and output transformer 8, the middle point of the moving transformer 4 is connected to the extreme points of the primary winding of the output transformer 8 and collectors of transistors 6 and 7 through the transitions of the anode cathode of diodes 9 and 10, respectively, and the emitters of transistors 3 and 2 are connected to the middle point of the transformer 8 through a transition of the cathode-anode of diode 11. The capacitor 12 and relay 13 with contacts 14 are are the startup scheme of the master generator. The converter also contains a source of pigment 15, a load 16 and capacitors 17 and 18.

The inverter works as follows.

When voltage is applied to the inverter circuit through a capacitor 12, a relay 13, which contacts 14 will turn on the starting circuit of the master oscillator 1: primary source 15, the primary winding of the transformer 8, diodes 9 and 19, the primary winding of the transformer 4, the indicator 18, the basic windings of the transistors of the transformer 4 , the base of transistors 2 or 3, closed contacts 14 relays 13.

After starting the master oscillator 1, for example, the transistor 2 is open, and the transistor 3 is closed, on the windings of transformer 4 there is an emf, with plus at the end, and minus at the beginning of the winding. This EMF opens the transistor 7, closes the transistor 6. On the windings of the transformer 8, the EMF is induced with polarity plus at the beginning and minus at the end of the winding. In load 16 and transformer 8, reactive energy is accumulated, which, after disconnecting pin 14, is used to power the master oscillator circuit. After the next switching - switching on of the transistor 7, the current in the primary and secondary circuits of the transformer 8 decreases according to a normal condition, retaining its initial voltage for some time, the alternating voltage on the primary half-winding of the transformer 8 changes its polarity in steps: the output of the closing transistor 7 from the saturation mode is accompanied by the discovery of a diode 9, which provides a circuit for returning the reactive energy accumulated in the previous half period. To provide a return circuit for this energy,

Diodes 9 and 10 are pressed. Reactive energy will open into this half-cycle with the following counter: transformer half winding 8, diode 9, transformer half winding 4, Q-E transition of transistor 3, diode 11, medium output terminal of a transformer 8. Return circuit in the next half period: transformer half winding 8, diode 1O, the semi-winding of the transformer 4, the transition K-E of the transistor 2, diode 11, the average output of the transformer 8.

Accumulated in the output transformer for the previous period, the reactive energy at the time of locking one of the transistors of the power amplifier under

, the action of self-induced EMF increases the voltage applied to it by a value of D U (. The time during which the voltage is exceeded is an insignificant part of the converter's working period, and the voltage value (. may exceed the value of the transistor transient voltage

tori power amplifier. At the same time, the power dissipated by transistors,

may reach unacceptably large values.

In the proposed device, such active losses are eliminated, and the accumulated reactive energy of the transformer 8 is used to power the master oscillator circuit 1, which increases the efficiency of the circuit compared to the prototype.

Claims (2)

Invention Formula A transistor inverter containing a master oscillator, the input terminals of which are connected to the input terminals of the inverter, and the output - to the input of a push-pull power amplifier with an output transformer, and one of the input terminals of the inverter and capacitor plate is connected to the center point of the primary winding of the latter. friend the plate is connected via diodes to the extreme outputs of the primary winding of a transformer, characterized in that, in order to increase efficiency, the common point of connection of the capacitor and diodes is connected to one short-circuit input terminals of the master oscillator, the other input terminal of which is connected to the common point of the primary output winding transformer through an additional diode. 57946986 Information sources, 2. Moin V, S, N. Laptev N.N. Stabi-, taken into account in the examination of transistor transforms1. The Avgorsk certificate of the USSR. M. Energy, 1972, p. 430, No. 290271, cl. H 02 M 5/10, 1971. Figure. 11-4e.