RU2644612C1 - Measuring transducer of variable voltage into constant one - Google Patents

Abstract

FIELD: electrical measuring equipment.

SUBSTANCE: invention refers to electrical measuring equipment and can be used in order to measure the alternating sinusoidal voltage by means of converting it to the constant one in the wide frequency range. Converter contains the differentiator, integrator, multiplier, quadrator, summing device and square root extraction unit. Converter input is connected to the inputs of the differentiator, integrator and quadrator, the output of which is connected to the non-inverting input of the summing device, the output of which through the square root extraction unit is connected to the output of the converter. Output of the integrator is connected to the second input of the multiplier, the output of which is connected to the inverting input of the summing device, and the output of the differentiator is connected to the first input of the multiplier.

EFFECT: technical result in the implementation of the claimed invention is widening of the operating frequency range of the converter.

1 cl, 2 dwg

Description

The invention relates to electrical engineering and can be used to measure an alternating sinusoidal voltage by converting it to constant in a wide range of frequencies.

Known Converter effective voltage [USSR Author's Certificate No. 822056, IPC G01R 19/22, publ. 04/15/1981], containing a half-wave rectifier, a quadrator, two low-pass filters, an amplitude detector, subtracting and summing devices, the output of the low-pass filter is connected to the input of the amplitude detector and to the non-inverting input of the subtracting device, and the output of the amplitude detector is connected to the inverting the input of the subtracting device and with one input of the summing device, the output of the subtracting device is connected to the input of an additional low-pass filter, the output of which is connected to another input of the sum iruyuschego device whose output is connected to the input focal quad is the output device.

The disadvantage of this converter is its low speed and accuracy of voltage measurement, due to the presence of low-pass filters in the DC signal path.

The closest analogue to the proposed utility model is a Measuring transducer of alternating voltage to constant [Patent PM PM No. 163230 of the Russian Federation, IPC G01R 19/22, publ. 07/10/2016], containing a phase shifter, a first and second quadrator, a summing device and a square root extraction unit, the input of the converter being connected to the inputs of the first quadrator and phase shifter, the output of which is connected to the input of the second quadrator, and the outputs of the first and second quadrators are connected, respectively to the first and second inputs of the summing device, the output of which through the square root extraction unit is connected to the output of the converter.

This technical solution is selected as a prototype.

The disadvantage of this converter is that, along with high speed and accuracy, its scope is limited only by measuring the voltage of the industrial frequency, since the phase shifter provides a phase shift of 90 ° only at this frequency. At other frequencies, the converter does not fulfill its function, since its output voltage will have a significant variable component, commensurate with the constant.

The technical result of the invention is to expand the operating frequency range of the Converter.

The specified technical result is achieved by the fact that in a known measuring transducer of alternating voltage to constant, containing a quadrator, a summing device and a square root extraction unit, the input of the converter connected to the input of a quadrator, the output of which is connected to a non-inverting input of the summing device, the output of which is through the square extraction unit the root is connected to the output of the transducer; in addition, a differentiator, an integrator, and a multiplication unit are introduced, moreover, the input of the transducer with is single with the inputs of the differentiator and integrator, the output of which is connected to the second input of the multiplication unit, the output of which is connected to the inverting input of the summing device, and the output of the differentiator is connected to the first input of the multiplication unit.

Significant differences of the proposed Converter are the introduction of a differentiator, integrator and multiplication unit. The combination of elements and the relationships between them ensure the achievement of a positive effect - the expansion of the operating frequency range of the Converter.

The invention is illustrated by drawings.

In FIG. 1 is a functional diagram of a converter; FIG. 2 - time diagrams of voltages u _in , u ₁ -u ₄ and u _out .

The converter (Fig. 1) contains a differentiator 1, an integrator 2, a multiplication unit 3, a quadrator 4, an adder 5 and a square root extraction unit 6.

The converter operates as follows. The measured AC voltage u _in = U _{m in} sinωt is supplied to the inputs of the differentiator 1, integrator 2 and quadrator 4.

At the output of the differentiator 1, a voltage u _{1 is formed} , which is shifted in phase relative to u _in by an angle of 90 ° in the direction of advance (Fig. 2):

where U _{m I} - the amplitude of the measured input voltage;

ω is the circular frequency of the input voltage;

R1 is the resistance of the differentiator resistor;

C1 - capacitor of the differentiator.

2 at the integrator output voltage u ₂ is formed, shifted in phase relative to u _Rin at 90 ° towards lag (figure 2.):

where U _{m I} - the amplitude of the measured input voltage;

ω is the circular frequency of the input voltage;

R2 is the resistance of the integrator resistor;

C2 - capacitor of the integrator capacitor.

When multiplying voltages u ₁ and u ₂ in the multiplication unit 3, voltage u ₃ is formed at its output:

When choosing the parameters of the components of the differentiator and integrator R1 = R2 = R, C1 = C2 = C, we have (Fig. 2):

подается на инвертирующий вход суммирующего устройства 5, на неинвертирующий вход которого подается напряжение

с выхода квадратора 4. В результате на выходе суммирующего устройства формируется напряжение u₅ (фиг. 2):Voltage

fed to the inverting input of the summing device 5, to the non-inverting input of which voltage is applied

from the output of the quadrator 4. As a result, the voltage u ₅ is formed at the output of the summing device (Fig. 2):

которое не содержит переменной составляющей.

which does not contain a variable component.

After extracting the square root in the square root extraction unit 6 at its output and at the output of the converter, we have a constant voltage u _o equal to U _{m in} , that is, proportional to the actual value of the input AC voltage U _in .

Thus, the output constant voltage u of the _output converter does not contain a variable component, and its value is proportional to the effective value of the input voltage U _in .

In the practical implementation of the proposed device, the differentiator 1 and integrator 2 can be performed on an operational amplifier (op-amp) with a time-varying RC circuit. When building the multiplication block 3 and quadrator 4, you can use voltage multipliers on the KR525PS3 microcircuit. The adder 5 is a parallel (differential) adder on the op-amp. As a block for extracting the square root of 6, you can use the op amp circuit by including the quad in its negative feedback circuit.

Claims (1)

An AC to DC measuring transducer comprising a quadrator, a summing device and a square root extraction unit, the input of the converter being connected to a quad input, the output of which is connected to a non-inverting input of the summing device, the output of which is connected to the output of the converter through a square root extraction unit, characterized in that a differentiator, an integrator and a multiplication unit are additionally introduced into it, and the input of the converter is connected to the inputs of the differentiator and a tegrarator whose output is connected to the second input of the multiplication unit, the output of which is connected to the inverting input of the summing device, and the output of the differentiator is connected to the first input of the multiplication unit.

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