SU1381458A1 - Device for converting a.c. to pulsating current with stabilization of mean components - Google Patents

Abstract

The invention relates to secondary power sources. The aim of the invention is to improve the accuracy of stabilization. The goal is achieved by alternately feeding half-wave sinusoidal current of industrial frequency. Each feed channel is an adjustable parametric stabilizer of the effective voltage value. The ratio of elements and the number of turns of the control windings of the transformer ensures a constant value of the mains voltage in the range of mains voltage changes + 15%. I il. i (L

Description

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The invention relates to electrical engineering, in particular to devices for converting alternating current into energy of the required kind.

The purpose of the invention is to demonstrate the accuracy of stabilization.

The drawing shows a schematic diagram of the proposed device. The device contains a transformer 1, the primary winding 2 of which is connected via technological contact 3 to the input terminals 4, two regulating elements, each of which is made on pass 5 and 6 and buffer 7 and 8 transistors. The collectors of transistors 5 and 6 are connected to the terminals of the secondary winding 9, the emitters are connected to the output terminals 10. The collectors of transistors 7 and 8 are connected to the first terminals of the control windings 13 and 1A via the isolating diodes 11 and 12 . The device also contains two control units of regulating elements, each of which includes a chain of serially connected first diode 15 and 16, first resistor 17 and 18, second diode 19 and 20, zener diode 21 and 22 and second resistor 23 and 24, two voltage dividers , each of which consists of two resistors 25 and 26 and 27 and 28, the outputs of which are connected to the bases of transistors 7 and 8. The terminals of the secondary winding are connected to the common bus through diodes 29 and 30. In addition, the device contains a forced mode unit 31.

The device works as follows.

The supply voltage is supplied from the machine station (not shown) through the process contact to the winding 2 of the transformer 1.

The device provides power to thermal cutters connected to terminals 10 according to the scheme of two symmetrical arms (channels). The power supply is carried out alternately with half-waves of sinusoidal current of a flushed frequency. Each arm of the device is an adjustable parametric stabilizer of the effective value of the constant component of the voltage. Due to the fact that the current passes through the thermal cutters during the half-period, to obtain the required value of the effective value, the amplitude of the supply voltage is doubled and the margin for losses and stabilization is added.

The use of an increased supply voltage with respect to a constant component of losses and an even number of channels (in our version of two) allows the use of low-power

0 a transformer, a driver for stabilizing each arm, and a compensating parametric amplitude limiter at Zener diodes 21 and 22. Operation for the first half period: negative half-wave sinusoid current of the second section is fed to the collector of the transistor 5 (regulating element, emitter, thermal junction and through transition of diode 30 to winding 9 of the current section of the transformer. In this half period, the diode 30 short circuits the circuit of the second current branch of the transformer I (transistor 6 and thermoresistant), and the secondary winding

5, an open junction diode 30 is connected to a grounded terminal.

When the phase changes, transistors 6 and 8 operate, and the circuit of transistors 5 and 7 is short-circuited through diode 29.

0 In order to keep open and drive the transistor 5 under low voltage conditions, it is necessary not only to exceed the total value of the losses on the circuit elements

g control, saturation voltage of the buffer transistor 7 (U 0.50, 7 v) and direct drop on diode 11 (Unp 1 v), but also create on the collector of the transistor 6 the minimum necessary operating voltage equal to 1-2 V .

Therefore, from the additional winding 13 of transformer 1, a half-wave of the same phase (but a higher voltage 5) is supplied through diode 11 (protection of transistors 7 and 5 against reverse voltage) to the collector of buffer transistor 7, and through limiting resistor 23 to a zener 21 forming the amplitude limiter half-wave.

From the antiphase section of the winding 14, turned out from the side of the grounded winding outlet, through the protective 5 diode 16 through the diode 20 to the cathode of the Zener diode 22 a positive half-wave is applied, which causes a dip in the straight half-wave, directed

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toward zero, compensating for the change in the width of the truncated half-wave (of the tooth from zero to the level of the slice, when the amplitude of the input voltage fluctuates.

Resistors 25 and 27 are located between the connection point of the resistor 23 and the Zener diode 21 and the base of the buffer transistor 7, so that the current of the thermal cutters is controlled by the booster circuit.

When the phase changes, the second half-wave sinusoid changes the polarity of the applied circuit voltages; the second one, identical to the first one, turns on, respectively, is earthed through the diode 29 of the upper output of the current section, and from the lower one is supplied with power through the transistor 6 to the load (while the diode 30 that shunt earlier this circuit is locked by reverse voltage), comes to the ground terminal and through the open diode 29 returns to the winding.

In the stabilization circuit, the Zener diode 22 and the diode 12, the resistors 28 and 24, and the buffer transistor 8 are turned on, respectively. The opening of the contacts occurs at the moment of switching on and is held for 0.5-1 sec with the help of an intermediate relay. , which leads to an increase in current through the spirals of thermal cutters by 15-20% in the forming mode.

With regard to the process of cutting and melting the edges of the fabric, the operation of the process contact 3 is carried out as follows. Before starting the process of cutting and melting

Neither the edges of the fabric, the technological contact 3 of the machine, which connects the primary winding of the transformer 1 to the power source, is closed. By switching on the relay contact, the formed jpasorpeaa mode takes place, lasting about 0.5 s. Due to the elastic properties of the fabric, the cutting and melting of its edge begins to occur at the moment of full heating of the thermal cutters. Up to this point, the fabric, stretching out, goes around the thermal cutters.

Claims (1)

Formula and inventions A device for converting alternating current into a pulsating with stabilization among the component, containing a power transformer, the primary winding of which is connected to the input terminals, two regulating elements and two control units, in order to increase the accuracy of stabilization of each of the regulating elements made on the pass-through and buffer transistors, with the transistors passing through the collectors connected to the terminals of the secondary winding, and the emitters to the output terminals, the base of the pass-through transistors n Connected to the emitters of the corresponding buffer transistors, the collectors of which through appropriately spreading diodes are connected to the first terminals of the two input control windings, the second terminals of which are combined and connected to the common bus, each of the control nodes including a chain of series-connected first diode, the first resistor a second diode, a zener diode and a second resistor, connected between the respective first terminals of the control windings, as well as a voltage divider, the input included I am waiting for the common bus and the junction point of the anode of the Zener diode and the second resistor, and the output connected to the base of the buffer transistor, in addition, the terminals of the secondary winding of the transformer are connected to the common bus through the inserted third diodes. L