SU1601608A1 - Pulsed a.c. voltage stabilizer - Google Patents

Abstract

The invention relates to electrical engineering and can be used to power electronic equipment. The purpose of the invention is to increase efficiency by reducing the dynamic losses on key elements. The output voltage is stabilized automatically by changing the ratio between the pulse duration of the one-shot 11 and the pause of the generator 9 of the pulse-width modulator 7. The pulse width of the one-shot 11 is determined by the signal from the comparison unit 6, the input connected to the output terminals of the stabilizer. The key elements 2, 3 and 4 are turned on so that the current through them is approximately equal to the load current 8, and the voltage on the closed key elements 2 and 3 is approximately equal to the load voltage 8. Depending on the sign of the output voltage deviation from the nominal value switching of key elements 2, 4 or 3, 4. Dynamic losses on key elements 2, 3 and 4 are reduced when switching, which provides an increase in efficiency. 2 Il.

Description

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The invention relates to electrical engineering, in particular to devices for controlling electrical quantities, and can be used, for example, to power electronic equipment.

The aim of the invention is to increase the efficiency by reducing the dynamic losses on the key elements.

Fig. 1 is a schematic of a pulse voltage regulator; .on FIG. 2 is a diagram of a pulse-width modulator with a comparison unit connected to it.

The stabilizer ((|) ig.1) contains choke 1, first 2, second 3 and third 4 key elements, capacitor 5 connected to output pins, comparison unit 6, connected input to capacitor 5, and output to pulse-width input modulator 7. Load 8 is connected to the output pins. ,

Pulse width modulator 7 (Fig. 2) contains a generator 9, the direct output of which through differentiating chain 10 is connected to the triggering input of a single-oscillator 11 with adjustable pulse duration, and logic cells AND 12 and 13 and EXCLUSIVE OR 14 with electrically developed ( for example, using the optron outputs, which are the first, second and third outputs of the pulse-width modulator 7, respectively. The inputs of logic gates AND 12 and 13 are connected to the direct and inverse outputs of the generator 9 and the single-oscillator 11, respectively inputs, logic cell 14 are connected to the direct output of the generator 9 and the inverse output of the one-shot 11, the control input of which is the input

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the turns of logic cells 12-14 are connected respectively to the first, second, and third outputs of the pulse-width modulator.

Comparison unit 6 comprises an output voltage amplitude sensor 15. and an adjustable voltage source 16, connected, for example, to a power amplifier, one of the inputs of which is connected to a reference source, and the other to the output of the sensor 15.

The first conclusions of the first 2 and second 3 key elements are connected

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five

respectively, with the first output and input terminals, and the second outputs, respectively, with the second input and output terminals, between which the choke 1 is connected. A third key element 4 is connected between the first input and output terminals. The first, second and third outputs of the pulse-width modulator 7 are connected respectively to the control inputs of the first 2, second 3 and third 4 key elements. The key elements 2-4 are made two-polar, for example, in the form of a transistor included in the diagonal of a rectifying bridge.

The stabilizer works as follows.

The switching frequency of the key elements is many times greater than the network frequency, and when the network voltage is above the nominal, the key element 3 is always closed. In this case, the comparison unit 6 and the pulse-width modulator 7 provide alternate opening of the key elements 2 and 4. At the moment of the open state of the key element 4, the choke 1 and the capacitor 5 accumulate energy. When the key element 4 is closed, the key element 2 opens and the choke 1 is discharged to the load .8. Consequently, at the moment of pause, the voltage on the load 3 is maintained by the energy in the capacitor 5 and the choke 1.

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3, the result of this conversion at the input of the filter formed by the choke 1 and the capacitor 5 is voltage pulses with a sinusoidal envelope with a mains frequency. The high-frequency components of this voltage are filtered by the choke 1 and the capacitor 5, so the voltage at the mains frequency appears at the output of the stabilizer.

The amplitude of the output voltage is determined by the duty cycle of the key 2. of element 2. In the stabilization mode, the duration of current pulses through the open key element 2 is automatically controlled by the comparator unit 6 and the pulse-width modulator 7. At the same time, the load 8. is supported. live voltage with constant amplitude.

When the network voltage is less than the nominal comparison unit 6, acting on the pulse-width modulator 7, provides alternate opening of the key elements 4 and 3 and the closed state of the key element 2. When the key element 3 is open, energy is accumulated in the dross 1. closing the key element 3 pulse-width modulator, 7 Provides the opening of the key element 4, the discharge of droplets 1 to the load 8 and the accumulation of energy in the capacitor 5.

When closing the key element 4, the capacitor 5 begins to discharge through the load 8, and the choke 1 through the open key element 3 again begins to accumulate energy. As a result, at the output of stabilizer 11 and at the output of the dog cell.12, the inputs of which receive signals from the direct outputs of the generator 9 and the one-oscillator 11, logic unit voltage appears from time to time. The duration of the voltage pulse at the output of logic 12 is equal to the difference between the durations of the pulse of the one-vibrator P and the pause of the clock 9. At the output of logic cell 13, under such conditions, the voltage of the logical zero is constantly maintained, and at the output of the logic cell 14 the voltage of the logical appears during a pause at the output of logic cell 12,

If the duration of the pause of the generator 9 is longer than the duration of the imp

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that network. The magnitude of this voltage is determined by the duty cycle of the current pulses through the key element 3. The constant amplitude at the output of the stabilizer is maintained automatically by the comparison unit 6 and the pulse width modulator 7, which regulate the duration of the current pulses through the key element 3.

Block 6. comparison works as follows.

The voltage from the output of the stabilizer is fed to the input of the sensor 15 amplitude. The output voltage, and from its output, a signal proportional to the amplitude of the output voltage, goes to the control input of the adjustable voltage source 16, in which the control voltage is compared with the reference voltage, and its output voltage linearly depends on the difference between these stress This voltage is fed to the input of the pulse-width modulator 7 and controls its operation.

The pulse width modulator 7 operates as follows.

The voltage from the output-block. 6 comparison is fed to the control input of a single vibrator I G with an adjustable pulse duration, which is started on the falling edge of a pulse of the generator 9 by a differentiating chain 10. At the same time, if the duration of the pause of the generator 9 is shorter than the duration of the pulse of a single vibrator P d signals taken from their direct outputs, the oscillator pulses 9 overlap and

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The unit appears periodically at the output of cell 13. The pulse duration at its output is the difference between the pause durations of the 5th rator gene 9 and the one-shot 1 pulse. At the output of the logiccake 12, the logic level is always zero exit cell 14

opposite logical levels on the output of cell 13.

Thus, by changing the duration of the pulses of the one-shot I1, it is possible to stabilize the output voltage 35 by making the level of the logical unit a friction opening the key elements. At the same time, if the network voltage is more than the nominal pulse duration of the one-oscillator 1I is longer than the duration of the pause of the generator 9. and, therefore, the key

40

element 3 is permanently closed, and key elements 2 and 4 are periodically switched.

45 When the voltage of the network is lower than the nominal pulse duration of the one-shot 1 becomes less than the duration of the pause of the generator 9 and as a result the key element 2 50 is permanently closed and the key elements 3 and 4 periodically switch.

The stabilization is carried out automatically by changing the ratio between the pulse duration of the single-oscillator and the 11th pause of the generator 9.

Dynamic losses on the key elements when switching, which is proportional to the product of the voltage on the key element in the closed, 601608 6

the one-shot 11 and the output of the dogic cell. 12, the inputs of which are fed from the direct outputs of the generator 9 and the one-shot 11, periodically, the voltage of the logical unit appears. The voltage pulse duration at the output of logic cell 12 is equal to the difference between the pulse durations of the one-shot P and the generator pause 9. At the output of logic cell 13, under such conditions, the voltage of the logical zero is constantly maintained, and at the output of the logic cell 14, the voltage of the logical unit appears during a pause at the output of the logic cell 12,

If the duration of the pause of the generator 9 is longer than the duration of the impulse10

15

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This unit periodically appears at the output of cell 13. The pulse duration at its output is equal to the difference between the durations of the pause generator 5 and 9 pulses of the one-shot 11. At the output of logic cell 12, the logic level is constantly maintained. cell output signals 14

opposite to logical levels at the output of cell 13.

Thus, by changing the duration of the pulses of the one-shot I1, it is possible to stabilize the output voltage 35 by making the level of the logical unit a friction opening the key elements. In this case, if the network voltage is greater than the nominal duration of a one-shot pulse. 1I is longer than the pause time of the generator 9. and, therefore, the key

0

element 3 is permanently closed, and key elements 2 and 4 are periodically switched.

5 When the voltage of the network is lower than the nominal pulse duration of the one-shot 1 becomes less than the duration of the pause of the generator 9 and as a result, the key element 2 0 is constantly closed, and the key elements 3 and 4 periodically switch.

The stabilization is carried out automatically by changing the ratio between the pulse duration of the single-oscillator 11 and the pause of the generator 9.

The dynamic losses on the key elements during switching, which are proportional to the product of the voltage on the key element in the closed state and the current through this key element in the open state, are approximately twice as low in the proposed stabilizer as in the prototype with other conditions being equal. Therefore, the efficiency of the proposed scheme is higher. In addition, in the prototype, voltage surges on key elements during a transitional ijiecca are possible due to the influence of the inductances of dispersion of chokes half-windings of drossel-1 or switching of key elements. It also reduces the efficiency of the prototype, as well as its reliability due to the possibility of the appearance of overvoltage on key elements. This disadvantage is absent in the proposed scheme, since the choke in it has one winding.

 Thus, in the proposed device, the efficiency coefficient is increased due to smaller Dynamic losses on the key elements.

Claims (1)

Invention Formula i A jro voltage regulator containing the first, second and third key elements, a choke, a capacitor connected to the output pins, a comparison unit connected by an input to a capacitor, and an output to an input of a pulse-width modulator consisting of from the generator, the direct output of which is through . one Editor O. Yurkovetska Compiled by A. Volkova Tehred M, Hodaiich Order 3270 Circulation 651 VNIIPI State Committee for Inventions and Discoveries at TKST of the USSR 113035, Moscow, Zh-35, 4/5 Raushsk nab. The differentiating chain is connected to the triggering input of a one-shot with an adjustable pulse width, the control input of which is connected to the input of a width-impulse modulator, two logical cells I, the inputs of the first of which are connected to direct, the inputs of the second are to inverse outputs of the generator and one-shot, and the outputs are connected respectively to the first and second outputs of the latitude and myelnnogo modulator, the logic cell EXCEPTED ISH, inputs which is connected to the direct output of the generator and the inverse output of the single vibrator, and the output to the third output of the pulse-width modulator, the first, second and third outputs of which are connected respectively to the control inputs of the first, second and. the third key elements, the first outputs of the first and second key elements being connected respectively to the first output and the first input input, characterized in that, in order to increase efficiency by reducing the dynamic losses on the key elements, the choke is connected between the second input and output outputs which are connected to the second conclusions of the first and second key elements, respectively, and the third key element included between the first input and output pins. Proofreader A.Osaulenko Subscription