MD490Z

MD490Z - Method for measuring the admittance components

Info

Publication number: MD490Z
Application number: MDS20110126A
Authority: MD
Inventors: Виталие НАСТАС
Original assignee: Технический университет Молдовы
Priority date: 2011-07-05
Filing date: 2011-07-05
Publication date: 2012-09-30
Also published as: MD490Y

Abstract

The invention relates to the field of electric and electronic measurements and can be used for high-precision measurement of admittance components.The method consists in the formation of a measuring circuit from the measured object, output terminals of an admittance converter with separate regulation of active and reactive components of the reproduced admittance and a signal generator connected in parallel, formation of a non-equilibrium signal and a reference signal, respectively, from the total current passing through the measured object and the output circuit of the converter, and from the current passing through the active component of the admittance reproduced by the converter with the conservation of phase of these currents, control of the phase shift between the non-equilibrium signal and the reference signal, equilibration of the measuring circuit by regulating the active and reactive components of the admittance reproduced by the converter concomitantly, up to the attainment of the phase shifts, respectively, of 90° (270°) and 0° (180°) between the non-equilibrium signal and the reference signal, and determination of components of the measured admittance from their known dependence on the components of the admittance reproduced by the converter.

Description

Invenţia se referă la domeniul măsurărilor electrice şi electronice şi poate fi utilizată pentru măsurarea cu precizie înaltă a componentelor admitanţei. The invention relates to the field of electrical and electronic measurements and can be used for high-precision measurement of admittance components.

Cea mai apropiată soluţie este metoda de măsurare a componentelor impedanţei, care constă în formarea unui circuit de măsurare din obiectul măsurat şi contactele de ieşire ale unui convertor de impedanţă, controlul semnalului de dezechilibru, obţinut în urma interacţiunii circuitului rezonant cu semnalul de măsurare, echilibrarea circuitului de măsurare prin reglarea impedanţei reproduse de convertor şi determinarea componentelor impedanţei măsurate din dependenţa lor de componentele impedanţei reproduse de convertor. Reglarea componentelor activă şi reactivă ale impedanţei reproduse se efectuează în două etape consecutive: la prima etapă se reglează componenta activă, iar la etapa a doua - componenta reactivă [1]. The closest solution is the method of measuring impedance components, which consists in forming a measuring circuit from the measured object and the output contacts of an impedance converter, controlling the unbalance signal obtained as a result of the interaction of the resonant circuit with the measurement signal, balancing the measuring circuit by adjusting the impedance reproduced by the converter and determining the components of the measured impedance from their dependence on the impedance components reproduced by the converter. The adjustment of the active and reactive components of the reproduced impedance is carried out in two consecutive stages: at the first stage, the active component is adjusted, and at the second stage - the reactive component [1].

Dezavantajele acestei metode sunt imposibilitatea măsurării directe a componentelor admitanţei şi timpul considerabil de măsurare din cauza echilibrării circuitului de măsurare în două etape consecutive, ceea ce complică aplicarea practică. The disadvantages of this method are the impossibility of directly measuring the admittance components and the considerable measurement time due to balancing the measurement circuit in two consecutive stages, which complicates practical application.

Problema pe care o rezolvă invenţia constă în lărgirea domeniului de aplicare şi reducerea timpului de măsurare. The problem that the invention solves consists in widening the scope of application and reducing the measurement time.

Metoda, conform invenţiei, înlătură dezavantajele menţionate mai sus prin aceea că constă în formarea unui circuit de măsurare din obiectul măsurat, bornele de ieşire ale unui convertor de admitanţă cu reglare independentă a componentelor activă şi reactivă ale admitanţei reproduse şi un generator de semnal, conectate în paralel, formarea unui semnal de dezechilibru şi a unui semnal de referinţă, respectiv, din curentul sumar, care trece prin obiectul măsurat şi circuitul de ieşire al convertorului, şi din curentul, care trece prin componenta activă a admitanţei reproduse de convertor cu păstrarea fazei acestor curenţi, controlul defazajului dintre semnalul de dezechilibru şi semnalul de referinţă, echilibrarea circuitului de măsurare prin reglarea componentelor activă şi reactivă ale admitanţei reproduse de convertor concomitent, până la atingerea defazajelor, respectiv, de 90° (270°) şi 0° (180°) dintre semnalul de dezechilibru şi cel de referinţă, şi determinarea componentelor admitanţei măsurate din dependenţa cunoscută a acestora de componentele admitanţei reproduse de convertor. The method, according to the invention, eliminates the above-mentioned disadvantages by consisting in forming a measuring circuit from the measured object, the output terminals of an admittance converter with independent adjustment of the active and reactive components of the reproduced admittance and a signal generator, connected in parallel, forming an imbalance signal and a reference signal, respectively, from the sum current passing through the measured object and the output circuit of the converter, and from the current passing through the active component of the admittance reproduced by the converter while maintaining the phase of these currents, controlling the phase shift between the imbalance signal and the reference signal, balancing the measuring circuit by adjusting the active and reactive components of the admittance reproduced by the converter simultaneously, until reaching the phase shifts, respectively, of 90° (270°) and 0° (180°) between the imbalance signal and the reference one, and determining the components of the measured admittance from their known dependence on the admittance components reproduced by the converter.

Rezultatul invenţiei constă în reducerea timpului de măsurare a componentelor admitanţei în coordonate carteziene. The result of the invention consists in reducing the time of measuring the admittance components in Cartesian coordinates.

Invenţia se explică prin desenele din fig. 1 şi 2, care reprezintă diagramele vectoriale ale procesului de măsurare. The invention is explained by the drawings in Fig. 1 and 2, which represent the vector diagrams of the measurement process.

Conform metodei propuse obiectul măsurat cu admitanţa YX, convertorul de admitanţă cu admitanţa de ieşire YR (MD 3111 G2 2006.07.31) şi generatorul de semnal cu tensiunea de ieşire UG formează un circuit rezonant paralel. Admitanţa măsurată YX şi admitanţa de referinţă YR, reprodusă de convertor, pot fi reprezentate în coordonate carteziene: According to the proposed method, the measured object with admittance YX, the admittance converter with output admittance YR (MD 3111 G2 2006.07.31) and the signal generator with output voltage UG form a parallel resonant circuit. The measured admittance YX and the reference admittance YR, reproduced by the converter, can be represented in Cartesian coordinates:

YX = GX + jBX\tab\tab\tab\tab\tab\tab\tab(1) YX = GX + jBX\tab\tab\tab\tab\tab\tab\tab(1)

YR = GR + jBR, (2)YR = GR + jBR, (2)

unde: GX, BX, GR, BR - respectiv, componentele activă şi reactivă ale admitanţelor măsurată şi de referinţă; where: GX, BX, GR, BR - respectively, the active and reactive components of the measured and reference admittances;

j - unitatea imaginară. j - imaginary unit.

Semnalul de dezechilibru Ide prezintă curentul sumar, care trece prin componentele activă şi reactivă ale admitanţelor măsurată (IX) şi de referinţă (IR) şi poate fi reprezentat: The unbalance signal Ide presents the sum current, which passes through the active and reactive components of the measured (IX) and reference (IR) admittances and can be represented:

Ide = IX + IR = UG(YX + YR) = UG[(GX +jBX) + (GR+ jBR)] (3) Ide = IX + IR = UG(YX + YR) = UG[(GX +jBX) + (GR+ jBR)] (3)

Admitanţa de referinţă YR se reproduce de convertorul de admitanţă cu posibilitatea reglării independente a componentelor activă GR şi reactivă BR. The reference admittance YR is reproduced by the admittance converter with the possibility of independent adjustment of the active GR and reactive BR components.

Echilibrarea circuitului de măsurare se efectuează prin două operaţii concomitente de reglare. La prima operaţie (vezi fig. 1) se reglează componenta activă GR a admitanţei de referinţă reprodusă de convertor până la valoarea GR0, curentul prin aceasta obţinând valoarea Acest moment se determină după egalarea cu 270° (curentul Ide) sau 90° (curentul Ide2) a defazajului dintre semnalele de dezechilibru Ide şi de referinţă . În operaţia a doua, executată concomitent cu prima (vezi fig. 2), se reglează componenta reactivă BR a admitanţei de referinţă până la valoarea BR0, curentul prin aceasta obţinând valoarea . Acest moment se determină după egalarea cu 180° (curentul Ide1) sau 0° (curentul Ide2) a defazajului dintre semnalele de dezechilibru Ide şi de referinţă . La finisarea procesului de echilibrare a circuitului de măsurare: The balancing of the measuring circuit is performed by two simultaneous adjustment operations. In the first operation (see Fig. 1), the active component GR of the reference admittance reproduced by the converter is adjusted to the value GR0, the current thereby obtaining the value This moment is determined after equalizing the phase shift between the Ide and reference unbalance signals with 270° (Ide current) or 90° (Ide2 current). In the second operation, performed simultaneously with the first (see Fig. 2), the reactive component BR of the reference admittance is adjusted to the value BR0, the current thereby obtaining the value . This moment is determined after equalizing the phase shift between the Ide and reference unbalance signals with 180° (Ide1 current) or 0° (Ide2 current). Upon completion of the balancing process of the measuring circuit:

UG[(GX + jBX) + (GR0 + jBR0)] = 0 (4) UG[(GX + jBX) + (GR0 + jBR0)] = 0 (4)

Soluţia ecuaţiei (4), care prezintă rezultatul măsurării, este: The solution to equation (4), which presents the measurement result, is:

GX = - GR0, BX = -BR0\tab\tab\tab\tab\tab\tab(5) GX = - GR0, BX = -BR0\tab\tab\tab\tab\tab\tab(5)

După cum rezultă din relaţia (5), la finisarea procesului de măsurare componentele activă şi reactivă ale admitanţei măsurate se exprimă respectiv prin componentele activă şi reactivă ale admitanţei de referinţă şi sunt reprezentate în coordonate carteziene. As follows from relation (5), at the end of the measurement process, the active and reactive components of the measured admittance are expressed respectively by the active and reactive components of the reference admittance and are represented in Cartesian coordinates.

Ca exemplu de implementare practică poate servi măsurarea componentelor admitanţei unui condensator cu componenta reactivă BX = 10-4 S şi componenta activă GX = 10-6 S. Din condensatorul măsurat şi bornele de ieşire ale convertorului de admitanţă se formează un circuit de măsurare paralel alimentat cu o tensiune UG = 10 V. În procesul echilibrării circuitului de măsurare se reglează componenta activă a admitanţei de referinţă până la valoarea GR0 = -10-6 S. Concomitent se reglează componenta reactivă a admitanţei de referinţă până la valoarea BR0 = 10-6 S. Valorile componentelor admitanţei măsurate constituie: GX = -GR0 = 10-6 S, BX = -BR0 = 10-4 S, acesta fiind rezultatul măsurării. As an example of practical implementation, the measurement of the admittance components of a capacitor with the reactive component BX = 10-4 S and the active component GX = 10-6 S can serve. A parallel measurement circuit powered by a voltage UG = 10 V is formed from the measured capacitor and the output terminals of the admittance converter. In the process of balancing the measurement circuit, the active component of the reference admittance is adjusted to the value GR0 = -10-6 S. At the same time, the reactive component of the reference admittance is adjusted to the value BR0 = 10-6 S. The values of the measured admittance components are: GX = -GR0 = 10-6 S, BX = -BR0 = 10-4 S, this being the result of the measurement.

1. MD 3577 G2 2008.04.30 1. MD 3577 G2 2008.04.30

Claims

Method for measuring admittance components, which consists of forming a measuring circuit from the measured object, the output terminals of an admittance converter with independent adjustment of the active and reactive components of the reproduced admittance and a signal generator, connected in parallel; forming an unbalance signal and a reference signal, respectively, from the sum current passing through the measured object and the output circuit of the converter, and from the current passing through the active component of the admittance reproduced by the converter while maintaining the phase of these currents; controlling the phase shift between the unbalance signal and the reference signal; balancing the measuring circuit by adjusting the active and reactive components of the admittance reproduced by the converter simultaneously, until reaching phase shifts, respectively, of 90° (270°) and 0° (180°) between the unbalance signal and the reference signal; determining the measured admittance components from their known dependence on the admittance components reproduced by the converter.