SU826533A1 - Two-cycle self-exciting inverter - Google Patents

Description

(54) TWO-TONE SELF-COMING) DISTRIBUTING INVERTER

one

The invention relates to electrical engineering and can be used in electrical power communication devices and computer equipment.

Known push-pull inverter containing power transistors, a starting transistor and a transformer fl.

The closest technical solution to the invention is a push-pull self-exciting inverter containing two main transistors connected to the primary semi-windings of the output transformer, including also the secondary winding and feedback winding, an auxiliary transistor connected by one power electrode to one of the terminals for connect the power source, and the base through a resistor to another terminal for connecting the source, a full-wave rectifier with a filter connected by an output are parallel to the emitter-base junction of the auxiliary transistor, which is connected launchers RC-2 chain.

The disadvantage of these inverters is low reliability due to the fact that when a power source with a smoothly increasing voltage is connected to the converter, for example, a rectifier with an output capacitive filter), one-sided saturation of the core of the output transformer occurs, which leads to the release of one of the main transistors. One-sided saturation of the transformer core occurs due to the fact that with a smooth increase in voltage from zero at low voltages, when the self-oscillating process in the converter has not yet arisen, the transformer core is magnetized by the current flowing through the shifted main transistor. -,

The purpose of the invention is to increase the reliability of the inverter.

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The goal is achieved by the fact that in a push-pull self-exciting inverter BE there is a threshold element connected between another power electrode of the auxiliary transistor and the base of one of the main transistors, and the rectifier input with a filter is connected to the primary half windings of the output transformer.

Claims (2)

The drawing shows the principle electric circuit of the inverter. The inverter contains two main transistors 1, included in the primary half windings 2 and 3 of the output transformer 4, also having a secondary winding 5 and a feedback winding b. The auxiliary transistor 7 is connected by one power electrode to one of the power supply terminals, another power electrode through the additionally introduced threshold cell 8 to the base of one of the main transistors 1, and the base through a resistor 9 to the other power supply terminal. A full-wave rectifier with a filter 10 is connected by an input to the primary half windings 2 and 3 of the output transformer 4, and the output is parallel to the transition emitter-base of the auxiliary transistor 7. The inverter works as follows. When the power source is connected to the inverter, the auxiliary transistor 7 is biased through the resistor 9, but the transistor 7 opens only when the supply voltage is equal to the trigger voltage of the threshold element 8, for example, on a zener diode. Through the open transistor 7, one of the main transistors 1 of the converter receives the connection and the latter goes into self-oscillation mode, i.e. The primary power source is connected to the primary transformers 4 and 3 of the transformer 4 by means of the main transistors, 1 and feedback windings 6, and a voltage appears on the secondary winding 5. Simultaneously, the primary semi-windings 2 and 3 of the transformer 4 are supplied with alternating voltage at the input of the full-wave rectifier with filter 10. From the output of the rectifier with the filter 10 to the transition of the emitter-base of the auxiliary transistor 7, a constant voltage is given and the latter is locked by this voltage and then, during operation, does not affect the self-oscillating process of the converter. Thus, in the case of a smooth increase in the supply voltage, the inverter self-excitation occurs when the supply voltage is not lower than a predetermined value, which is determined by the threshold element 8. This prevents the output transformer 4 from touching the core, since the auxiliary transistor 7 is locked by the voltage of the half-winding 2 and 3 transformer 4 through a rectifier with filter 10. The last, closing, removes the bias circuit at one of the main transistors. Performing the rectifier with the filter 10 in the inverter in a full-wave circuit helps to eliminate the constant biasing component of the transformer core 4. Connecting the rectifier with the filter 10 input to the primary half windings 2 and 3 of the transformer 4 creates a circuit for discharging the reactive energy accumulated and inductance of the windings 2 and 3 to the capacitor of the rectifier with the filter 10 at the time of locking the main transistor, to help protect the main transistors. The effectiveness of the proposed device in comparison with the known one is to increase the reliability by preventing the core of the output transformer from saturation when the power supply is connected to the device. the constant component of magnetization of the same core and the protection of the main transistors against transients. re-voltage at the time of switching. The invention of the push-pull spontaneous} Shakhin1 inverter, containing two main transistors connected to the primary semi-winding circuit of the output transformer, including the secondary winding and feedback winding, an auxiliary transistor, is connected (shy one power electrode to one of the terminals for connecting the power supply , and the base through a resistor - to another terminal for connecting the power source, full-wave rectifier with filter, connected by the output parallel to the emitter-base transition of the VSS A subnuclear transistor, to which is also connected an RC start-up chain, characterized in that, in order to improve the inverter’s reliability, a threshold element is inserted in it, connected between another silosm of the auxiliary transistor and the base of one of the oscillation transistors, and the input of the rectifier Metel with is connected to the primary semi-windings of the output transformer.Sources of information taken into account during the examination 1. USSR author's certificate №628596, cl. H 02 M 7/537, 1977. 2. Information reference leaf No. 7.58,72, GONTI-7, 1972.