SU1272276A1 - Meter of parameters of complex impedance - Google Patents

Abstract

This invention relates to a measurement technique. It can be used to measure resistance parameters, for example, its modulus and phase angle. The purpose of the invention is to improve the measurement accuracy of parameters of a compact resistance, the phase angle of which is close to the phase angle of an exemplary element, achieved by forming, measuring and processing the phase difference of the signals of the exemplary element and complex resistance. Dp this unit entered subtractive blocks 3, 5 and 6, the adder 4 and the phase shifter 7. The drawing also shows a generator 1 of a sinusoidal signal, an exemplary element 2, converters 8 and 9 of the phase difference in the code, computing unit 10, the investigated impedance 11, input terminals 12 and 13. The device can calculate other parameters, such as, for example, the capacitance of a condensator using a sequential replacement circuit, the tangent of dielectric loss angle. The calculation formulas are given in the specification. I il. Yu Yu Yu Oi

Description

The invention relates to electrical measuring equipment and can be used to measure resistance parameters, for example, its modulus and phase angle.

The aim of the invention is to improve the accuracy of measurement of the parameters of the impedance, the phase angle of which is close to the phase angle of the sample element, due to (Normalization, measurement and processing of the phase difference of the signals of the sample element and the complex resistance.

The drawing shows a block diagram of an impedance parameter meter.

The device contains a sinusoidal signal generator 1, sample element 2, the first subtraction unit 3, the adder 4, the second and third subtraction units 5 and 6 ,. phase shifter 7, first and second converters 8 and 9 of phase difference into a code, computing unit 10, test impedance 11 connected to first and second input terminals 12 and 3

The output of the generator 1 is connected to the first input of the first subtractive unit 3, the first output of the model element 2 and the reference input of the first converter 8 phase difference in the code, the second output of the exemplary element 2 is connected to the second inputs of the first and third subtractive blocks 3 and 6, the input of the phase shifter 7 and the first input terminal 12, the output of the first subtractive unit 3 is connected to the first inputs of the adder 4, the second and third subtractive blocks. 5 and 6, the output of the phase shifter 7 is connected to the second inputs of the adder 4 and the second subtractive unit 5, the output to torogo connected to the reference input of the phase difference in the second code converter 9, and its signal input connected to the output of the adder 4 and the input of the first transducer signalnsh 8 different. Phase to code is connected to the output of the third subtractive unit 6, the outputs of the first and second converters 8 and 9 of the phase difference to the code are connected to the corresponding inputs of the computing unit 10.

The device works as follows.

When the measuring circuit is energized from generator 1 by alternating voltage with amplitude V on sample element 2 and measuring complex resistance I1, voltage drops U and L are respectively:

R

and V ZS-- V

(one)

- P

 5 Rg f + 1 R1

17 TG

(2)

V -. -,. "- .- .y

P 5 C. pf + r

exemplary resistance

Q Resistor

Z, I

- measured impedance with module Zj (and phase angle 9

 7

R - xozE -I- JX sin b (3)

0

X (4)

20 R,

At the output of the first subtraction unit 3, a voltage U is created (with respect to the common busbar), and at the output de phase shifter 7, the voltage 0 is shifted by an angle of 90 °, i.e. - jU ,.

The voltage U, at the output of the adder 4, Uj at the output of the second subtractive unit 5 and Uj at the output of the third subtractive unit 6, taking into account the formulas

(1) - (3) are equal respectively

 V --- i-

and, and „- JU,

n 1 + t

.n 9 - j xco & 0

(5) 35 - 1 + XCOS0 + jxsin9

1 + iP

U Uo + JU, V -; - 4-

(6)

1 + XCOS0 + jxsin9 n iinf

 v.

u Uo - U,

 jxsin0

(7) 1 + XCOS0 + jxsinO P

Claims (1)

These voltages, as well as the voltage of the generator 1, are fed to the inputs of the converters 8 and 9 of the phase differences into a digital code. In this case, at the output of the second converter 9, a code is obtained proportional to the phase angle (f voltage U with respect to voltage U, and at the output of the first converter 8, code proportional to the phase angle (fj voltage with respect to voltage and. These angles, as follows from formulas (5) - (7), are equal to T xcos6 xcos in t, - (arc tg «« t: g- -rxsin6 xsin6 M.-Carctg -3 ---- + arctg 7; -; From expressions (8 ) and (9) determine the desired parameters of the impedance J 7 -R diiis: ii-s: ± -i-5. (10 g-P t tg., x o. + 9 arctg where a is signcg Q ,, Computation parameters of complex resistance Z and 0 are carried out in numeral block 10 by output values (f and Cf, first and second converters 8 and 9 of phase variance into a code in accordance with formulas (10) and (11). You can also calculate other parameters of the impedance, for example, capacitance Cd of capacitor n of the series circuit replacement and its dielectric loss tangent is tg B according to the formulas -SlL J. where Cd is the circular frequency of the generator I. The invention The measuring instrument of the complex resistance parameters containing the generator of the sinusoidal signal, the output 764 of which is connected to the output of the reference element, the second output of which is connected to one of the input terminals of the meter, the other input terminal of which is connected to the common bus, the first and second converters of the phase difference into a digital code, the reference input of the first converter of the phase difference into a digital code connected to the output of the sinusoidal signal generator and a computing unit, the inputs of which are connected to the outputs of the first and second converters of the phase difference into a digital code, respectively, characterized in that, in order to improve the accuracy of the steam measurement a complex impedance phase, whose phase angle is close to the phase angle of the reference element, the first, second and third subtractive blocks, an adder and a phase shifter are entered into it, the output of the sinusoidal signal generator being connected to the first input of the first subtraction block, and its output being connected to the first inputs of the second and the third subtractive blocks and the adder, the second output of the model element is connected to the second inputs of the first and third subtractive blocks and the input of the phase shifter, the output of which is connected to the second inputs the adder and the second subtraction unit, the output of the adder is connected to the signal input of the first phase difference converter in the code, and the output of the second subtraction unit is connected to its reference input, the output of the third subtraction unit is connected to the signal input of the second phase difference converter in the code.