SU1576886A1 - Ac voltage stabilizer - Google Patents

Abstract

The invention relates to electrical engineering, in particular to secondary power sources with stabilized alternating current. The purpose of the invention is to increase efficiency. OBJECTIVE achieved in that an AC voltage regulator provided with on-off switching regulator 15, a DC voltage output is connected to the second DIAGONALS BRIDGE SWITCH 8 K second input of comparator 17, voltage input connected to the output rectifier bridge 6 and the control input is connected to output of the comparator 17 VOLTAGE. STABILIZATION OF THE OUTPUT VOLTAGE IS PROVIDED BY CHANGING THE AMPLITUDE OF THE TRAPTIVE VOLTAGE AT THE OUTPUT OF THE STABILIZER 15, COMPENSATING FOR THE DEVELOPMENT OF THE NETWORK VOLTAGE. At positive and negative deviations from the nominal voltage NETWORK AS SOURCE sinusoidal voltage autotransformer LOW RANGE USED TRANSFORMER WINDING 2 1. SOURCE trapezoidal voltage is used on-off switching voltage regulator DC (PSI) 15 fed from the bridge rectifier 6. Addition of two voltages performs bridge switch 8, performed on the keys 9-12 with two-way conductivity. The sum of the voltages is applied to the output of the stabilizer, to which the load 14 is connected. The measuring element 16 generates information about the deviation of the output voltage of the stabilizer from the nominal and delivers it as a reference voltage to one of the inputs of the voltage comparator 17, to the other input of which Potentiometer 18 receives information about the magnitude of the voltage at the output of the SPI. 15. The output voltage of the SPV is maintained at the reference level. Depending on changes in the magnitude of the mains (input) voltage and load, the amplitude of the trapezoid voltage varies, and the output voltage is kept constant with the accuracy and high efficiency determined by the circuit parameters. 4 il.

Description

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conductivity. The sum of the voltages is fed to the output of the stabilizer, to which the load 14 is connected. The measuring element 16 produces information. A deviation of the output voltage of the stabilizer from the nominal voltage and supplies it in the form of a reference voltage to one of the inputs of the voltage comparator 17, the other input of which .JQ from the potentiometer 18 receives information about the voltage value at the output of the SOS 15. Voltage The output ČSN is maintained at the reference level. Depending on the changes in the magnitude of the mains input voltage and the load, the amplitude of the trapezoid voltage varies, and the output voltage is kept constant with the accuracy of the circuit parameters and high efficiency. 4 il.

The invention relates to electrical engineering and can be used to stabilize the voltage of electrical receptacles fed from an industrial AC network, in particular, household appliances.

The purpose of the invention is to increase efficiency,

FIG. Figure 1 shows a block diagram of an AC voltage regulator; Fig 2 is a circuit diagram of a stabilizer; in fig. 3 - diagrams explaining the operation of the stabilizer; in fig. 4 is a diagram of the path of current flow at different time intervals. . .

The voltage regulator contains a transformer 1 equipped with an autotransformer winding 2 and step-down windings 3-5, bridge rectifiers 6 and 7 connected to the windings 3 and 4 of transformer 1, bridge switch 8 made on keys 9-12 with two-sided conductivity, to control - the output of which is connected to the outputs of the amplifier maker 13 control pulses. One of the diagonals of the switch 8 is connected in series with the autotransformer winding 2 of transformer 1 and with load 14 connected to the output pins, and the other diagonal of switch 8 is connected to the output of the on-off stabilizer 15 of the DC voltage, the input of which is connected to the output of the bridge rectifier 6. A measuring element 16 is also connected to the stabilizer output, the output of which is connected to one of the inputs of the voltage comparator 17, the second input of which is connected via a potentiometer 18 to the output of the two-position onnogo switching regulator 15, and the output - to the input

20

25 30

35 40 45-p 55

control key 19 two-position pulse stabilizer 15.

Keys 9-12; FIG. 2} are transistors 20-23 with diodes 24-27 connected anti-parallel to them. Amplifier driver 13, made of transistors 28 and 29 and the output transformer 30, the input is connected to the step-down winding 5 of the transformer 1. The two-stage pulse stabilizer 15 contains a switch 19, a choke 31, a capacitor 32, and a diode 33. Measuring element 16 contains an isolation transformer 34, rectifier 35, filter 36, differential amplifier 37, reference voltage source, made in the form of a Zener diode 38 and connected to one of the inputs of the amplifier 37..

The AC voltage regulator operates as follows.

The network voltage applied to the autotransformer winding 2 of transformer 1 may deviate in magnitude to a smaller or larger side than the nominal value. The voltage at the output terminals of the transformer winding 2, less than the nominal voltage, is summed by means of the switch 8 with the automatically controlled voltage obtained at the output of the two-position pulse stabilizer 15 of the DC voltage. The voltage at the output of the on-off pulse stabilizer 15 is controlled in such a way that the total voltage received at the output of the AC voltage regulator is constant in magnitude with varying mains voltage. For this, the measuring element 16, connected to the output of the stabilizer, generates an error signal, proportional to

Voltage deviation is applied to one of the inputs of the voltage comparator 17 and is the reference voltage for the comparator 17. The second input of the comparator 17 is supplied using a potentiometer 18, the output voltage of the on-off pulse stabilizer 15, the Comparator 17 produces a signal that enables the transistor switch 19 of the on-off pulse stabilizer 15 if the voltage supplied from the potentiometer 18 is less than the reference voltage supplied from the measuring element sixteen.

As long as the instantaneous value of the voltage supplied to the on-off pulse stabilizer 15 from the output of rectifier 6 is less than the reference voltage (Fig. 3, the intervals between the eighth and first and between the sixth and third time points), the switch 19 is unlocked and the output of the stabilizer is supplied rectifier 6 (minus the internal voltage drop in the two-stage switching regulator 15).

When the instantaneous voltage at the input of the on-off pulse stabilizer 15 exceeds the reference, the comparator 17 stops the unlocking signal, the key 19 is recorded, the throttle current 31 closes through the diode 33, the stabilizer capacitor 32 begins to discharge the load current, the ratio of the voltages at the inputs of the comparator I7 it reverses, the key 19 is unlocked, and the processes are repeated — the key 19 is periodically unlocked and backed up, and the voltage at the output of the on-off pulse stabilizer 15 is maintained aets level determining reference voltage emom zheniem- (fig.Z, the intervals between the fifth and sixth and seventh and eighth between time instants).

The switching frequency of the key 19 is usually from hundreds of hertz. to tens of kilohertz, and the amplitude of the voltage pulsations at the output of the stabilizer 15 is tens to hundreds of millivolts. FIG. 3, the frequency of switching is conventionally underestimated and the amplitude of pulsations is overestimated.

When lowering the output voltage of the stabilizer, for example, due to a decrease in the network voltage, the voltage

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The output of the measuring element 16 increases, as a result of this, the voltage at the output of the two-position pulse stabilizer 15 increases and compensates for the decrease in the output voltage of the stabilizer. When the output voltage rises, the output voltage of the two-station

The jq of the pulse stabilizer 15 is lowered, compensating for the increase in voltage.

The voltage UCT at the output of the stabilizer 15 is unipolar, and for it

Adding jr with a voltage UT of overlay 2 of transformer 1 serves as a bridge switch 8, the keys 9-12 of which, for providing double-sided conductivity, are made on reverse diodes 2420 27 and transistors 20-23 controlled by square-shaped pulses from the output of the shaping amplifier 13, represented by a power transformer 30 and transistors 28 and 29,

25 voltage controlled windings 5 of the transformer 1, so that the keys of the switch 8 are controlled synchronously with the network voltage. FIG. 3 and 4 illustrate the addition of the voltages of the autotransformer winding 2 and. two30

35

positional pulse stabilizer 15 at a lagging (inductive nature) load current, as well as the operation of key elements of the stabilizer. FIG. 3 respectively shows the time curves of the stresses on

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UH (at the output of the AC voltage regulator), the output voltage of the pulse stabilizer and the load current iri, and ® conditionally (by wide lines) are the unlocked state of the corresponding numbering keys of the circuit. The points in time correspond: the first and third to the current zero crossing, the fourth and second to the voltage transition through the culture, the fifth, sixth, seventh and eighth - to the beginning and end of the operation of the key 19 in the switching mode.

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When the polarity of the voltage and the direction of the current coincide (FIG. 4a, the interval between the first and second moments, time in FIG. 3), transistors 20 and 23 (FIGS. 2 and 4) of switch 9 and 12 of switch 8 and the current are unlocked load flows through the circuit: froster 2 - load 14 - transistor 23 - two-pole pulse stabilizer

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15 - transistor 20 - winding 2. In the next interval (Fig. 4b, the time between the second and third moments in Fig. 3), the current retains the voltage, and the direction changes the polarity. The control signal sold from the amplifier — the driver TK to the transistors 20-23 — is reversed, the transistors 20 and 23 are locked, the transistors 21 and 22 of the keys 10 and 11 of the switch 8 receive an unlocking signal, but due to the fact that the load current has not yet changed direction, transistors 21 and 22 cannot unbolt $ and unlock diodes 25 and 26. When the load current changes direction, transistors 21 and 22 begin to conduct (Fig. 4c, the interval between the third and fourth time points Fig. 3). After the voltage changes polarity, a unlocking signal is applied to the transistors 20 and 23, but they are not unlocked because the current has not changed direction yet, and the diodes 24 and 27 are unlocked (Fig. 4, the time between the fourth and first moments on fig.Z). Further, the processes are repeated. When the direction of the current corresponds to the polarity of the voltage (, c), energy is transferred to the load from the winding 2 of transformer 1 and through the rectifier 6 and the stabilizer 15 from the winding 3 of transformer 1, and when current flows in the direction opposite to the polarity of the voltage ( 4b, d), the energy comes from the winding 2 of transformer 1 to the load and partially to stabilizer 15, but since stabilizer 15 and exporter 6 cannot provide energy recovery to the network, this energy is stored in condenser 32 of stabilizer 15 charging it up to a voltage exceeding the instantaneous value of the voltage on the winding 3 of the transformer 1. In order for this excess not to play a significant role in the operation of the stabilizer, the capacitance of the capacitor must be chosen

from this condition (the excess voltage is inversely proportional to the capacitance of the capacitor). In the next time interval, the energy stored in the capacitor is transferred to the load.

The winding 4 of the transformer 1 and the rectifier 7 are designed to power the amplifier-former 13, the measuring element 16 and the comparator 17

Thus, in the proposed stabilizer, the efficiency is ensured due to the operation of all elements in the key mode with slight distortions in the shape of the output voltage of the AC voltage regulator.

Claims (1)

Invention Formula An AC voltage regulator containing a transformer equipped with two step-down and auto-transformer windings, a bridge rectifier connected to one of the step-down windings of the transformer, a measuring element, an input connected to the output terminals, and an output to one of the inputs of the voltage comparator, bridge a switch made on keys with two-sided conductivity, one diagonal of which is connected in series with the output pins and the tap-off of the autotransformer winding connected to the input to one of the pins, the driver of the control pulse shaper, the outputs of which are connected to the inputs of the bridge switch keys, and the input to the other of the down-windings of the transformer, characterized in that, in order to increase efficiency, the stabilizer is equipped with a two-position pulse stabilizer of DC voltage The output of which is connected to the second diagonal of the bridge switch and to the second input of the voltage comparator, the input is connected to the output of the bridge rectifier, and the control input is connected to the output of the comparator Yeni. Ј5 - «s to M (S 1 (4 5 -4 1 "L i ui Qt VS 00 Oj at: Ј " №P irt / 5i L. zfTj igs Fy