SU1073864A2 - D.c.-to a.c. voltage converter - Google Patents

Abstract

CONVERTER VOLTAGE V-VARIABLE CONVERTER on autor. SB. 849394, which is also distinguished by the fact that, in order to improve the shape of the output voltage, an additional winding of a power transformer was introduced in it, the outputs of which through corresponding diodes and current limiting resistors are connected to the collectors of the corresponding transistors of the additionally introduced switch, whose control inputs are connected to different outputs of the available trigger, the emitters of these transistors are connected to the average output of the specified additional winding and the clamp of the generator of short pulses, o for its output and control parts, and the collectors through the OR element are connected to the control part of the specified generator. and pit iVer / gksch Vyl1) d

Description

The invention relates to electrical engineering and can be used in secondary power sources.

According to the main auth. No. 849394 is known a DC-to-AC converter which contains a short pulse generator, a counting trigger synchronized from this generator, a guaranteed delay pulse shaper, an inverter, and the base-emitter transitions of which are connected to the trigger outputs and to the transmitter through the ejection current node. impulses of guaranteed delay, the specified impulse generator was used as a generator of impulses of guaranteed delay; The output of the through-current exclusion unit consists of newly introduced additional windings of a short pulse generator transformer, the number of which is equal to the number of inverter transistors and each of them is connected to the base circuit of the corresponding transistor 1J.

The disadvantage of this converter is the fixed turn-on delay of the inverter transistors, designed for the maximum duration of the absorption process of the excess carriers of these transistors, which takes place at the minimum load. At rated load, when the dissipation time, the smallest form of the output voltage deteriorates due to the appearance of a pause at zero at the moments of switching transistors.

The purpose of the invention is to improve the shape of the output voltage by introducing an automatic adjustment of the switching delay time.

This goal is achieved by introducing an additional winding of a power transformer into a DC / AC converter, the terminals of which through appropriate diodes and current-limiting resistors are connected to the collectors of corresponding transistors of an additionally inserted switch, the control inputs of which are connected to the opposite outputs of the existing trigger, the emitters of these switches transistors are connected to the average output of the specified additional winding and the generator terminal of short pulses c, common to its output and control parts, and the collectors through the OR element are connected to the control part of the specified generator.

FIG. 1 shows a DC / AC converter circuit; FIG. 2 diagrams of stresses, which show his work.

The converter contains a generator of 1 short pulses with an output transformer 2 equipped with three secondary windings 3–5, the latter two of which form the node 6 for the exclusion of through currents, a counting trigger 7 connected with the generator 1 of short pulses (with a winding 3 of its output transformer 2), an inverter 8 with two power transistors 9 and 10, the bases of which are connected to the outputs of the trigger 7 through the node 6 to exclude the through currents (windings 4 and 5, the power transformer 11, the primary winding of which is connected to the collectors of the transistors 9, 10 of the inverter, the pulse expansion unit 12 of the generator 1 with the switch 13 connected thereto, made on transistors 14 and 15 and resistors 16 and 17 through which the bases of these transistors (the control inputs of the switch 13j are connected to the outputs of the trigger 7. Element OR 18 is connected the transistors 14 and 15 of the switch 13, and the collectors of the transistors 14 and 15 through the current-limiting resistors 19 and 20, the diodes 21 and 22 are connected to the auxiliary winding 23 of the power transformer 11. The control part 24 of the generator 1 is connected to the OR element 18. The output part of the generator 1 - tr The anzistor 25 is connected to the primary winding 26 of the transformer 2.

. FIG. 2 shows the voltage plots: 27 — the control part 24 of generator 1; 28 and 29 - at the outputs of the trigger 7; 30 and 31 - at the terminals of the winding 23/32 - at the output of the element OR 18; 33 - on the windings of the transformer 2/34 and 35 - at the inputs of the inverter 8.

The DC / AC converter operates as follows.

The generator 1 produces on the windings 3, 4, 5, 26 of its output transformer 2 narrow voltage pulses 27, whose frequency and duration in the absence of external control actions is determined by the control part 24. When these pulses come from winding 3 to the trigger input 7 its state changes at the outputs (plots 28 and 29 / As a result, transistors 9 and 10 of inverter 8 turn on alternately, and rectangular form voltages are formed on the windings of power transformer 11 (plots 30 and 31).

Let the state of the trigger 7 be such that the transistor 9 is open, with

which opens the transistor 14 of the switch 13 through the resistor 16, the output voltage of the element OR

18 is absent, but from the half winding

23 through the diode 21 and the resistor 19 the collector current of the transistor 14 flows. When a control pulse arrives from the generator 1 at the input 7 of the control pulse, the next switching on of the transistor 10 is delayed by the counter voltage of the coil 5 (plot 33). At the same time, the voltage on the winding 4 facilitates the resorption of minority carriers in the transistor 9. The voltage on the winding 23 at this stage retains its sign and, since the transistor 14 is already closed, the current from the winding 23 through the diode 21 resistor

19 and the OR element 18 of the block 12 flows through the control junction of the transistor 25, supporting & its enabled state is at the end of the action of the control part-24 (epupa 32). This state of the transistor

25 is maintained until the voltage on the winding 23 disappears, which occurs at the time of the dissolution of the transistor 9, therefore, the duration of the voltage pulses

transformer windings 2 | The plot 33 is determined by the resorption time of the locking transistor, which provides an automatic switch-on delay of the next transistor (plots 34 and 35. For normal operation of the voltage converter, the windings 4 and 5 must exceed the output voltage of the trigger 7.

The automatic delay of switching on the power transistors of the inverter, received by introducing an additional winding of the power transformer connected to the control part of the short pulse generator, eliminates pauses in the output voltage of the converter, i.e. improves the shape of this stress.

Claims (1)

DC CONVERTER V - VARIABLE by ed. No. 849394, characterized in that, in order to improve the shape of the output voltage, an additional winding of the power transformer is introduced into it, the water of which is connected through the corresponding diodes and current-limiting resistors to the collectors of the corresponding transistors of the additionally introduced switch, the control inputs of which are connected to the opposite outputs of the existing trigger, the emitters specified transistor. The ditch is connected to the middle terminal of the indicated additional winding and to the clamp of the short pulse generator common to its output and control parts, and the collectors are connected through the OR element to the output of the control part of the specified generator.