RU185973U1 - Device for measuring the period of oscillation - Google Patents

Abstract

The utility model relates to electronics and measuring equipment, namely to measuring periods of infra-low-frequency signals. The device contains a rectifier, a bipolar power source, a pulse generator, a comparator. A bipolar power source is two series-counter-connected power sources made on two supercapacitors. The pulse generator is made in the form of a reference frequency generator. The device also contains a voltage divider, the output of which is connected to the input of the rectifier, the output of which is connected to the filter. The filter output is connected to a voltage regulator, the output of which is connected to a low-pass filter, the output of which is connected to a comparator through a bipolar power source. The output of the comparator is connected to the input of the galvanic isolation device, the output of which is connected to the C-input of the control trigger. The output of the control trigger is connected to the input of the reference frequency generator. The output of the reference frequency generator is connected to the input of the logical signal processing unit, the outputs of which are included in the buffer memory, the pulses from which are fed to decoders, the outputs of which are connected to the corresponding bits of the reading indicator device. The technical result consists in expanding the functionality of the device by measuring the period of low-frequency oscillations and detecting the presence of modulated modes in electric power systems and networks. 3 ill.

Description

The technical solution relates to electronics and measuring equipment, namely to measuring periods of infra-low-frequency signals.

As a result of the frequency difference of various generators (machine type or static converters) operating on a common network, modulation occurs in the electric power system, which leads to the appearance of modulated modes in the electric power system.

To eliminate modulation, synchronous operation of the generators on one network is required, with constant monitoring and mutual adjustment of the frequencies of the parallel running generators. The dynamics of the operation of machine-type generators is “soft”. However, statistical converters are rigidly tied in frequency. Therefore, when a similar type of current source is connected to the network, it can cause overloading of machines and electrical devices due to the inertia of frequency equalization of machine generators.

When the current source, the static converter, is connected to the network, the machine generator is unloaded and its operating frequency increases due to the inertia of the processing of the automatic control system (ATS). The spread of frequencies can cause an increase in the current of the machine generator, which can lead to the operation of the current protection.

To eliminate this phenomenon, it is advisable to “tie” the frequency of the static generator to the frequency of the machine generator, that is, the static converter must be slave, and the machine generator must be leading.

It is known "Device for frequency control" (RF Patent No. 2007731, IPC G01R 23/00, published February 15, 1994) containing a first trigger, the direct output of which is the first output of the device, a second trigger, the direct output of which is the second output of the device , the three AND elements are NOT, and the inputs of the third AND element are NOT connected to the direct outputs of the first and second triggers, and the output is the third output of the device, two one-shots, characterized in that an additional D-trigger is inserted into it, the D-input of which is connected with bus "Earth", C-input - with C-input the first one-shot, the inverse input of which is connected to the input of the device, and the output is connected to the C-inputs of the first and second triggers and to the S-input of the additional trigger, while the one-shots are made on D-triggers, the direct input of one of them through an integrating circuit is connected to its an input, and the integrating circuit resistor is shunted by a diode, the D-input is connected to the Earth bus, the second one-shot, the D-input of which is connected to the Earth bus, the C-input - with the output of the first one-shot, the third input of the first AND element - NOT and D-input first tr ggera, the output of the second monostable multivibrator is connected to the D-input of the second flip-flop and a second input of the first element I - NOT, the first input of which is the input device and an output coupled to the C-input of the first monostable multivibrator.

A disadvantage of the known device is the low noise immunity of the device to pulsed transients in the measured circuits.

The closest in technical essence and the achieved technical result and selected as a prototype is a "Device for controlling the period of oscillation" (Aut. St. USSR No. 1099288, IPC-3 G01R 23/15, BI-23-84,), containing the unit start and reset, the counter, the first pulse shaper, the output of which is connected to the first input of the start and reset unit, the reset and resolution outputs of which are connected to the corresponding inputs of the counter, and its second input - with the output of the counter overflow, as well as a reference generator, the output of which connected to the signal input of the counter, characterized in that a second pulse shaper, two OR elements, two switches, two integrators, two comparators, a counting trigger and a voltage reference are introduced into it, the first and second inputs of the second pulse shaper connected respectively to the outputs of the first a pulse shaper and a reference generator, and the output is connected to the first input of the first OR element, to the second input of which the reset output of the start and reset unit is connected, and the signal is connected to the output of the first OR element the first input of the first switch, while the input of the counting trigger is connected to the output of the first pulse shaper, its output is connected to the control inputs of the first and second switches, the first output of the first switch is connected through the first integrator and the first comparator connected in series to the first input of the second OR element, the second the output of the first switch through a second integrator and a second comparator connected in series to the second input of the second OR element, while the second output of the counter is connected to gates of the first and second comparators, the third counter output with the control input of the second switch, the outputs of which are connected to the reset inputs of the first and second integrators, and the outputs of the reference voltage source are connected to the corresponding inputs of the comparators.

The disadvantage of the prototype is its narrow functionality.

The objective of this utility model is to develop a new circuitry for a device for measuring the oscillation period with the achievement of a technical result - expanding the functionality of the device by measuring the period of low-frequency oscillations, detecting the presence of modulated modes in electric power systems and networks.

The task is carried out by the fact that in the "Device for measuring the period of oscillation" containing a rectifier, a pulse generator, a comparator, a pulse generator is made in the form of a reference frequency generator, while the output of the voltage divider is connected to the input of the rectifier, the output of which is connected to the filter, the output of which connected to a voltage stabilizer, the output of which is connected to a low-pass filter, the output of which is connected to a comparator through a bipolar power source, and the output is connected to the input of the galvanic device isolation, the output of which is connected to the C-input of the control trigger, the output of which is connected to the input of the reference frequency generator, while the output is connected to the input of the logical signal processing unit, the outputs of which are connected to the buffer memory, the pulses of which are fed to the decoders, the outputs of which are connected with the corresponding bits of the reading indicator device, in addition, the voltage divider is made on resistors, the rectifier is made on elements on two zener diodes, a capacitor and two resistors, the filter is made It is connected to capacitors, a voltage stabilizer is made on zener diodes, a low-pass filter is made on an operational amplifier, resistors and capacitors, a bipolar power supply is two series-counter-connected power supplies made on two supercapacitors, a comparator is made on an operational amplifier and resistors, a galvanic device decoupling is made on an optocoupler pair, a logic element and resistors, a control trigger is made on a logic element DD2, the generator is standard nth frequency is made on logic elements DD1-2 and DD1-3, resistors and a capacitor, the logical signal processing block is made on elements “DD ”-2, DD4-DD9, buffer memory is made on logic elements DD10-DD13, decoders are made on logic elements DD14-DD17, the reading device indicator is made on the logical elements DD18-DD21.

The essential features of the proposed technical solution that match the prototype are the following features:

- rectifier;

- bipolar power source;

- pulse generator;

- comparator.

Distinctive from the prototype of the essential features of the proposed technical solution are the following features:

- the pulse generator is made in the form of a reference frequency generator;

- the output of the voltage divider is connected to the input of the rectifier;

- the rectifier output is connected to the filter;

- the filter output is connected to a voltage regulator;

- the output of the voltage regulator is connected to a low-pass filter;

- the output of the low-pass filter through a bipolar power source is connected to the comparator;

- the output of the comparator is connected to the input of the galvanic isolation device;

- the output of the galvanic isolation device is connected to the C-input of the control trigger;

- the output of the control trigger is connected to the input of the reference frequency generator;

- the output of the reference frequency generator is connected to the input of the logical signal processing unit;

- the outputs of the logical signal processing unit are included in the buffer memory;

- pulses from the buffer memory are supplied to the decoders;

- the outputs of the decoders are connected to the corresponding bits of the reading indicator device.

- the voltage divider is made on the resistors R1 and R2;

- the rectifier is made on the elements VD1, VD2, C1, R3 and R4;

- the filter is made on capacitors C2 and C3;

- voltage stabilizer is made on Zener diodes VD3 and VD4;

- the low-pass filter is made on an operational amplifier DA1-1 and elements R5-R9, C4-C6;

- a bipolar power source is two series-counter-connected power source, made on two supercapacitors C _b ;

- the comparator is made on the operational amplifier DA1-2 and elements R10-R12;

- the galvanic isolation device is made on an optocoupler pair VS1, a logic element DD1-1 and resistors R13 and R14;

- the control trigger is made on the element DD2;

- the reference frequency generator is made on elements DD1-2 and DD1-3, resistors R15, R16 and capacitor C7;

- the block of logical signal processing is performed on elements DD3-2, DD4-DD9;

- buffer memory is made on the elements DD10-DD13;

- decoders are made on the elements DD14-DD17;

- the reading indicator device is made on the elements DD18-DD21.

Between the essential distinguishing features of the claimed technical solution and achieved with their help a technical result - the expansion of the functionality of the device - there is the following cause-effect relationship.

Indeed, the use of a new set of circuit elements and new connections between them allows you to get a new device that can perform, in addition to the main function - measuring the period of oscillation of low-frequency signals with a frequency of 4 Hz, several additional functions - to measure frequency, to determine the beat of frequency oscillations and the modulation frequency voltage.

In FIG. 1 shows a functional diagram of the device, FIG. 2 shows a circuit diagram of a device; FIG. Figure 3 shows the plots of the pulses arriving for recording in the block of logical signal processing (BLOS).

The inventive device for measuring the period of oscillation contains:

- voltage divider 1, made on resistors R1 and R2;

- rectifier 2, is made on the elements VD1, VD2, C1, R3 and R4;

- filter 3 made on capacitors C2 and C3;

- voltage stabilizer 4, made on the zener diodes VD3 and VD4;

- low-pass filter 5, made on the operational amplifier DA1-1 and elements R5-R9, C4-C6;

- bipolar power source 6, which is two series-counter-connected power source, made on two supercapacitors C _b ;

- a comparator 7, made on the operational amplifier DA1-2 and elements R10-R12;

- galvanic isolation device 8, made on an optocoupler pair VS1, a logic element DD1-1 and resistors R13 and R14;

- trigger control 9, performed on the element DD2;

- a reference frequency generator 10, made on the elements DD1-2 and DD1-3, resistors R15, R16 and capacitor C7;

- block logical signal processing 11, performed on the elements DD3-2, DD4-DD9;

- buffer memory 12, is made on the elements DD10-DD13;

- decoders 13, made on the elements DD14-DD17;

- reading device indicator 14, made on the elements DD18-DD21.

In this case, the pulse generator is made in the form of a reference frequency generator 10, and the output of the voltage divider 1 is connected to the input of the rectifier 2, the output of which is connected to the filter 3, the output of which is connected to the voltage regulator 4, the output of which is connected to the low-pass filter 5, the output of which is through the bipolar power source 6 is connected to the comparator 7, and the output of the comparator 7 is connected to the input of the galvanic isolation device 8, the output of which is connected to the C-input of the control trigger 8, the output of which is connected to the input of the etalizer hydrochloric frequency 10, the output of the reference frequency generator 10 is connected to an input logic signal processing unit 11, which outputs are enabled on the buffer memory 12 at which the pulses supplied to decoders 13, the outputs of which are connected to respective bits of reading device indicator 14.

In the inventive device, an alternating voltage U is supplied to a voltage divider 1, the voltage from which is supplied to a filter 3, the output of which is connected to a voltage regulator 4.

The low-pass filter 5 is an active low-pass filter, the elements of which are given according to the calculated data on the transfer function of the Chebyshev filter, characterized by a sharp decrease in the amplitude-frequency characteristic (AFC) in the transition band, but in the passband these characteristics are not flat. According to the calculated data, the slope slope is up to 4 Hz. The output of the low-pass filter 5 through a bipolar power source 6 is connected to the comparator 7.

The output of the comparator 7 is connected to the input of the galvanic isolation device 8. The galvanic isolation device 8 is designed for galvanic isolation of the analog voltage processing circuits from the logical data processing circuits. The output signals from the galvanic isolation device 8 is supplied to the control trigger 9, the input of which also receives pulses of calibrated frequency from the reference frequency generator 10.

The output of the trigger 9 is connected to the input of the logical processing unit of the signal 11, the output of which is included in the buffer memory 12. The pulses from the buffer memory 12 are fed to a decoder 13, the output of which is connected to a reading device - indicator 14.

The inventive device operates as follows.

The input voltage of 220 V is supplied through a voltage divider 1 (Fig. 1), made on resistors R1, R2, a capacitor C1 on a half-wave rectifier 2. assembled on diodes VD1 and VD2 (Fig. 2). Capacitor C1 passes only the AC component of the voltage. The outputs of the diodes VD1 and VD2 through current-limiting supports R3, R4 are connected to a filter 3 made on capacitors C2, C3 with voltage stabilization by a parametric voltage regulator 4, assembled on VD3, VD4 to power the microcircuits and circuit elements.

The voltage from voltage divider 1, made on the resistors R1, R2, is fed to the input of the low-pass filter 5, assembled on the elements R5, R6, R7, R8, C4, C5, C6, DA1-1. The parameters of the low-pass filter 5 are selected according to the calculated data according to Chebyshev. Slope steepness for Chebyshev filter up to 4 Hz. Resistances R5 ÷ R8 are selected according to calculations, with nominal values of 91 kOhm, C4 = 1 μF, C5 = 1.2 μF, C6 = 0.15 μF. The chip for the low pass filter 5 is selected K140UD20. The output of the low-pass filter 5 is connected to a bipolar power source 6, assembled on electrolytic capacitors C _b . The voltage from the bipolar power source 6 is supplied to the inverse input of the comparator 7, made on the operational amplifier DA1-2. The output of the comparator 7 is connected to the light emitting diode of the optocoupler pair VS1. The gain DA1-2 is 30, the output frequency is f = 4 Hz.

The output of the optocoupler through the "OR" circuit DD1-1, assembled on K561LA7 is connected to the control trigger 9, performed on the element DD2 (561TM2). Direct output DD2 is connected to a reference frequency generator 10, made on the elements DD1-2, DD1-3, R15, R16. The inverse output DD2 is connected to the pulse shaper circuit DD3, DD4 and through the control circuit DD3-3, DD4-5, DD4-6, DD5-1, DD5-2, DD5-3, DD5-4, DD5-5, the signal is written to the buffer memory 12 with a delay of 75 ns. The signal from the buffer memory 12 receives the decoder 13, made on the elements DD14, DD15, DD16 and then fed to the reading device indicator 14, made on the elements DD17 (AAC314A). In this scheme, the period T is measured. The signal conversion is shown by the waveforms of the signals (Fig. 3). To convert period T to frequency f, a conversion table is needed.

This device allows you to determine the period of oscillation of the frequency of the mains voltage from 4 Hz and allows you to determine the frequency of the low-frequency signal, the beat of oscillations and the frequency of voltage modulation.

Thus, we can conclude that the task posed in this utility model — the development of a new circuitry for a device for measuring the oscillation period — is achieved with a technical result — expanding the device’s functionality, since it allows using it in the design and manufacture of frequency response meters, in t .h. period of oscillation, mainly low and infra-low frequency range.

Claims (1)

A device for measuring the oscillation period, comprising a rectifier, a bipolar power source, a pulse generator, an indication unit, characterized in that the pulse generator is made in the form of a reference frequency generator, and the indication unit is made in the form of a reading indicator device made on a logic element, while the output of the voltage divider is made on two resistors and connected to the input of the rectifier, made on the capacitor, two resistors and a block of the logic element, the output of which is connected to the filter, on capacitors, the output of which is connected to a voltage stabilizer made on zener diodes, the output of which is connected to a low-pass filter made on an operational amplifier, five resistors and three capacitors, the output of which is through a bipolar power source, which is two series-connected counter-connected power sources made on two supercapacitors is connected to a comparator made on an operational amplifier and three resistors, and the output of the comparator is connected to the input of the device isolation isolation performed on an optocoupler pair, a logic element and two resistors, the output of which is connected to the C-input of a control trigger made on a logic element - a trigger, the output of which is connected to the input of a reference frequency generator made on an optoelectronic pair, a logic element and two resistors , while the output is connected to the input of the logical signal processing unit, executed on a logic element, the outputs of which are included in the buffer memory, executed on logic elements, pulses with They arrive at decoders made on triggers, the outputs of which are connected to the corresponding bits of the reading indicator device.

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