RU2501025C1 - Bridge meter of parameters of n-element dipoles - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: in a bridge meter of parameters of n-element dipoles there is an additional resistor, an additional inductance coil, a build-up circuit is identified, quantity of such circuits is determined, and they are connected to each other. The total quantity of identical build-up circuits is equal to a quotient from division of n-2 into four (n-number of parameters in a dipole of the measurement object), if this quotient from division is an integer number. At the same time the last build-up circuit is complete, if the quotient from division contains integer and fractional parts, then the number of build-up circuits is equal to the integer part plus one, and the last build-up circuit is incomplete. The total quantity of elements in each of two identical dipoles in the second branch of the bridge is equal to the number of parameters n in the dipole of the measurement object, each subsequent build-up circuit is connected in parallel to the inductance coil of the previous build-up circuit.

EFFECT: expansion of functional capabilities of a meter, namely, a bridge meter makes it possible to determine parameters of R-C, R-L and R-L-C dipoles of measurement objects comprising five, six and more elements.

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Description

The invention relates to instrumentation, automation and pro-electronics, it can be used to measure the parameters of objects that can be represented by equivalent circuits in the form of multi-element passive two-terminal devices, and it can also be used to determine the parameters of the sensors.

Known meter parameters of multi-element passive two-pole according to the author's certificate of the USSR No. 1247762, MKI G01R 17/10, 1986, Bull. No. 28, containing a series-connected pulse generator with voltage changes over their duration according to the law of power functions, a bridge circuit for determining the R, L, C parameters of two-terminal devices and a zero indicator.

Its disadvantage is the inability to determine the parameters of resistive-inductive (R-L) and resistive-capacitive (R-C) two-terminal devices.

Known bridge meter parameters of n-element passive two-pole according to the author's certificate of the USSR No. 1150556, G01R 17/10, 1985, Bull. No. 14, containing a series-connected pulse generator with a voltage change over their duration according to the law of power functions, a bridge circuit for determining the parameters of resistive-capacitive (R-C) two-terminal devices and a zero indicator.

The disadvantage of this meter is the lack of advanced functionality, that is, it cannot be used to determine the parameters of resistive-inductive (R-L) two-terminal and two-terminal with heterogeneous reactive elements (R-L-C).

The closest in technical essence and the achieved result is a bridge meter of the parameters of four-element passive two-terminal devices (AS USSR No. 918862, G01R 17/10, 1982, BI No. 13), containing a series-connected pulse sequence generator of complex shape, an electric bridge circuit and zero indicator.

Its disadvantage is limited functionality, namely, it does not allow measuring the parameters of more than four elements of two-terminal objects of measurement.

, если частное от деления является целым числом. При этом последняя цепь наращивания является полной, если частное от деления содержит целую и дробную части, то количество цепей наращивания равно целой части плюс единица, и последняя цепь наращивания является неполной и состоит из дополнительного (третьего) резистора, конденсатора и второго резистора. При этом свободный вывод второго резистора заземлен, или последняя цепь наращивания состоит из дополнительного (третьего) резистора и конденсатора, а свободный вывод последнего заземлен и, наконец, последняя цепь наращивания представляет собой только один дополнительный (третий) резистор, общее число элементов во втором двухполюснике второй ветви моста равно количеству элементов в двухполюснике объекта измерения, каждая последующая цепь наращивания вторая, третья и т.д. подключается параллельно индуктивной катушке предыдущей цепи наращивания, количество формирователей в генераторе импульсов равно числу элементов в двухполюснике объекта измерения или в его схеме замещения.The technical result is achieved by the fact that in the parameter meter n-element two-terminal network containing a pulse generator, which consists of pulse shapers with a change in voltage over their duration according to the law k ₀ · t ⁰ , k ₁ · t ¹ , k ₂ · t ² , ..., k _n-1 · t ^n-1 , where k ₀ , k ₁ , k ₂ , ... are constant coefficients (t _i is time, n is the number of elements in the two-terminal network of the measurement object or in its equivalent circuit), switch, inputs which are connected to the outputs of the pulse shapers, and the output is connected to a power amplifier, the output of which forms the first the th output relative to the ground of the pulse generator, the synchronization unit, the output of which is connected to the synchronization inputs of the pulse shapers, and its output forms the second output relative to the ground of the pulse generator (synchronization output), the common bus of the pulse generator is grounded. The first output of the pulse generator is connected to the input of the four-armed AC bridge, the first branch of which includes two terminals for connecting two-terminal measuring objects and a single resistor, the first terminal of which is connected to the first output of the pulse generator, and the free output of a single resistor to ground , the common terminal of the second terminal and a single resistor forms the first terminal of the bridge circuit output. Parallel to the first branch of the bridge chain, its second branch is included. It consists of two series-connected two-terminal, the common output of which forms the second output terminal of the bridge circuit, the second two-terminal network is multi-element and consists of series-connected first resistor and the first inductive coil, the free terminal of the first resistor is connected to the common terminal of two two-terminal devices of the second branch of the bridge, and the free output of the inductive coil is grounded. The second two-terminal device consists of a series-connected capacitor and a second resistor, the free terminal of the capacitor is connected to the common terminal of the first resistor and inductive coil; a null indicator, to the differential input of which two outputs of the bridge circuit output are connected: one to the synchronization input, the second to the output of the pulse generator, the common bus of the null indicator is grounded, an additional resistor, an additional inductive coil and build-up circuits are introduced, and in the second branch of the bridge two two-terminal circuits are identical in the number of elements, their composition and inclusion, an additional (third) resistor is connected in parallel with the first inductive coil of the second multi-element two-terminal of the second branch m core circuit, an additional (second) inductive coil is included in the second multi-element bipolar of the second branch of the bridge between the free output of the second resistor and the ground, an additional (third) resistor, a capacitor, a second resistor and an additional (second) inductive coil form an extension circuit, the total number identical growth chains is equal to the frequency of dividing (n-2) by four $$\left[\frac{n-2}{\mathrm{four}}\right]$$

if quotient of division is an integer. Moreover, the last chain of extension is complete, if the quotient of the division contains the integer and fractional parts, then the number of chain of extension is equal to the integer part plus one, and the last chain of extension is incomplete and consists of an additional (third) resistor, capacitor and second resistor. In this case, the free terminal of the second resistor is grounded, or the last extension circuit consists of an additional (third) resistor and capacitor, and the free terminal of the latter is grounded and, finally, the last extension circuit is only one additional (third) resistor, the total number of elements in the second two-terminal network the second branch of the bridge is equal to the number of elements in the two-terminal network of the measurement object, each subsequent chain of building a second, third, etc. it is connected parallel to the inductive coil of the previous build-up circuit; the number of formers in the pulse generator is equal to the number of elements in the two-terminal network of the measurement object or in its equivalent circuit.

The invention is illustrated in the drawing (figure 1).

The bridge meter of the parameters of n-element two-terminal contains a generator 1 of voltage pulses, which includes n shapers of voltage pulses, changing over their duration according to the law of power functions (n is the number of elements in the two-terminal of the measurement object); voltage shaper 2 k ₀ · t ⁰ , voltage shaper 3 (k ₁ · t ¹ ), voltage shaper 4 k ₂ · t ² etc, where k _i are constant coefficients, t is the current time. The outputs of the shapers are connected to the inputs of the switch 5, the output of which is connected to the input of the power amplifier 6, the output of which forms the first output of the pulse generator 1. The output of the synchronization unit 7 is connected to the synchronization inputs of each of the pulse shapers, and also forms the second output, the synchronization output of the pulse generator 1 The common bus of the pulse generator 1 is grounded.

The first output of the pulse generator 1 is connected to the input of the four-arm bridge circuit, the first branch of which contains two terminals for connecting two-terminal measuring objects and a single resistor 8 (R ₈ ), the free output of which is grounded. An example of a two-terminal device with heterogeneous reactive elements (RLC) contains a resistor 9 (R ₉ ), in parallel with which a circuit is connected from a series-connected capacitor 10 (C ₁₀ ), resistor 11 (R ₁₁ ) and inductive coil 12 (L ₁₂ ). An example of a resistive-inductive bipolar (RL) comprises a series-connected resistor 13 (R ₁₃ ) and an inductive coil 14 (L ₁₄ ), in parallel with which a series-connected resistor 15 (R ₁₅ ) and an inductive coil 16 ((L ₁₆ ) are connected. And finally , an example of a resistive-capacitive two-terminal device consisting of a resistor 17 (R ₁₇ ), in parallel to which a capacitor 18 (C ₁₈ ) and a resistor 19 (R ₁₉ ) are connected in parallel, a capacitor 20 (C ₂₀ ) is connected in parallel. connecting two-terminal objects measured and a single resistor 8 (R ₈ ) form the first output terminal of the bridge circuit.

Parallel to the first branch of the bridge chain, its second branch is included. It consists of two series-connected identical multi-element bipolar, the common output of which forms the second output output of the bridge circuit. Each of the same bipolar contains an initial circuit of a series-connected resistor 21 (R ₂₁ ) and an inductive coil 22 (L ₂₂ ). In parallel to the inductive coil 22 (L ₂₂ ), a circuit from a resistor 23 (R ₂₃ ) is connected, in parallel to which a circuit from a series-connected capacitor 24 (C ₂₄ ), a resistor 25 (R25) and an inductive coil 26 (L ₂₆ ) is connected. Elements 23, 24, 25, and 26 form the first extension chain 27 (indicated by dashed lines in the figure). Then, in parallel with the inductive coil 26 (L ₂₆ ), a second extension circuit 28 (circled by dashed lines) is connected, the same with the first extension circuit, similarly, the third extension circuit, etc. The last chain of extension can be complete if n-2 is divided into four without a remainder. If with a remainder, then the last extension circuit is incomplete and contains only one first resistor or first resistor and capacitor, and finally, the first resistor, capacitor, and second resistor. The total number of elements in the discussed two-terminal network is equal to the number of elements in the two-terminal network of the measurement object n, or the number of parameters in the equivalent circuit of the measurement object.

Identical with the first multi-element bipolar, the second bipolar of the second branch of the bridge circuit contains the same initial circuit 29 (R ₂₉ ), 30 (L ₃₀ ), elements 31 (R ₃₁ ), 32 (C ₃₂ ), 33 (R ₃₃ ) and 34 (L ₃₄ ), forming the first chain of building 35 (circled by a dashed line), then the second chain of building 36, etc.

Both outputs of the bridge circuit output are connected to the differential input of the null indicator 37. Its synchronization input is connected to the second output of the pulse generator 1. The common bus zero of the indicator is grounded.

Like common bipolar parameter meters, the model elements of the bridge circuit 8, 21, 22, 23, 24, 25, 26, ... have known and constant parameter values. Model elements 29, 30, 31, 32, 33, 34, ... have known adjustable parameter values and are used to balance the bridge circuit. And, finally, the elements 9, 10, 11, 12 ..., 13, 14, 15, 16 ..., 17, 18, 19, 20 ..., have unknown unknown parameters and belong to two-terminal objects of measurement.

Before the start of the next pulse from the generator 1, the reactive elements of the bridge circuit are free of energy reserves, and the voltage at the input and output of the bridge is zero. At each stage of balancing, under the influence of the next pulse in the bridge circuit at the beginning of the pulse and after its end, transients occur in the form of voltage surges at the output, which decay to zero during the transition process. Useful is the part of the pulse from the output of the bridge from the end of the transition process to the end of the pulse, it has a flat top. Let us consider the operation of a bridge meter when a measurement object with heterogeneous reactive elements 9, 10, 11, 12 is connected to a two-terminal (RLC) bridge circuit. At the beginning, a rectangular pulse (k ₀ · t ⁰ ) is applied to the bridge from generator 1 through a switch 5. By adjusting the resistance value 29 (R ₂₉ ), we bring the flat peak of the pulse voltage from the bridge output (nonequilibrium voltage) to zero, noting this hereafter with reference to indicator 37, which can be used as an oscilloscope. As a result, the first equilibrium condition is satisfied.

$$A_{\mathrm{one}}=R_8\cdot R_{21}-R_9\cdot R_{\mathrm{29th}}=0.(\mathrm{one})$$

The reference value of the unknown resistance value 9 (R ₉ ) is taken from the equilibrium condition (1), where the parameter values of all other elements are known.

After that, pulses of a ramp voltage (k ₁ · t ¹ ) are supplied to the bridge circuit by means of a switch 5 from generator 1. By adjusting the value of the inductance of the coil 30 (L ₃₀ ) the flat peak of the impulse voltage of the disequilibrium is reduced to zero and thereby the second equilibrium condition is satisfied

$$A_2=R_8\cdot L_{22}-R_9\cdot L_{\mathrm{thirty}}+R_8\cdot R_9{R}_{21}\cdot C_{10}=0.(2)$$

Do not adjust the resistance value 29 (R ₂₉ ), as this will lead to a violation of the equilibrium condition (1), which is unacceptable. The count of the unknown parameter 10 (C ₁₀ ) is taken from expression (2), because the remaining quantities in it are known, including the resistance value R ₉ from expression (1).

Then, quadratic pulses (k ₂ · t ² ) are supplied to the bridge circuit by means of a switch 5 from generator 1. By adjusting the resistance value 31 (R ₃₁ ), the flat peak of the impulse nonequilibrium voltage is reduced to zero and the third equilibrium condition is satisfied

$$\begin{array}{l}{A}_3=R_8\cdot R_9\cdot R_{21}\cdot R_{23}\cdot L_{\mathrm{thirty}}\cdot C_{10}+R_8\cdot R_9\cdot R_{21}\cdot R_{31}\cdot L_{22}\cdot C_{10}+R_8\cdot R_{23}\cdot L_{22}\cdot L_{\mathrm{thirty}}-\\ -R_9\cdot R_{\mathrm{eleven}}\cdot R_{23}\cdot R_{31}\cdot L_{\mathrm{thirty}}\cdot C_{10}-R_9\cdot R_{31}\cdot L_{22}\cdot L_{\mathrm{thirty}}=0.(3)\end{array}$$

The parameters of elements 29 (R ₂₉ ) and 30 (L ₃₀ ) cannot be adjusted, because the fulfillment of the first two equilibrium conditions (1, 2) is violated. The count of the unknown parameter 11 (R ₁₁ ) is taken from (3), because the remaining quantities in it are known, including 9 (R ₉ ) from (1) and 10 (C ₁₀ ) from (2).

For example, the three stages of balancing the bridge chain are detailed. Further, in the subsequent stages, balancing, pulses from the generator are used with a change in voltage according to the law of the third, fourth, fifth, etc. degrees. The number of balancing stages and the number of forms of supply pulses used are equal to the number of parameters in the two-terminal devices of the measurement objects. At each stage, the flat peak of the disequilibrium voltage is reduced to zero in the time interval from the end of the transition process to the end of the supply pulse. This is realized by adjusting the values of the balancing element, which was not used at the previous stages of balancing and was not included in the previous equilibrium conditions. In particular, on the fourth, fifth, sixth, etc. the balancing steps are sequentially used to control the balancing elements 32 (C ₃₂ ), 33 (R ₃₃ ), 34 (L ₃₄ ), etc. The reference for the desired parameters is taken from the equilibrium conditions.

When connecting a resistive-inductive (RL) two-terminal circuit to the bridge circuit of the measurement object 13, 14, 15, 16, ..., the above balancing steps are used in the previous sequence. The same forms of supplying pulsed signals, the same adjustable parameters and the previous sequence of regulation of their values are saved: R ₂₉ , L ₃₀ , R _31, ... Equilibrium conditions for the first three stages are given:

$$A_{\mathrm{one}}=R_8\cdot R_{21}-R_{13}\cdot R_{\mathrm{29th}}=0(\mathrm{four})$$

$$A_2=R_8\cdot L_{22}-R_{13}\cdot L_{\mathrm{thirty}}-R_{\mathrm{29th}}\cdot L_{\mathrm{fourteen}}=0(5)$$

$$\begin{array}{l}{A}_3=R_8\cdot R_{23}\cdot L_{22}\cdot (R_{31}\cdot L_{\mathrm{fourteen}}+R_{\mathrm{fifteen}}\cdot L_{\mathrm{thirty}})-R_{13}\cdot R_{31}\cdot L_{\mathrm{thirty}}(R_{23}\cdot L_{\mathrm{fourteen}}+R_8\cdot L_{22})-R_{\mathrm{fifteen}}{L}_{\mathrm{fourteen}}\cdot (R_{\mathrm{29th}}\cdot R_{31}\cdot L_{22}+\\ +R_{23}\cdot L_{\mathrm{thirty}}\cdot (R_{\mathrm{29th}}+R_{31}))=0.(6)\end{array}$$

Of these, the parameter values are taken: R ₁₃ , L ₁₄ , R ₁₅ , ...

If an R-C diode is connected to the bridge circuit, then the same forms of supply pulses are used, the same adjustable parameters and the previous sequence of regulation of their values.

The equilibrium conditions for the first three stages:

$$A_{\mathrm{one}}=R_8\cdot R_{21}-R_{17}\cdot R_{\mathrm{29th}}=0(7)$$

$$A_2=R_8\cdot L_{22}-R_{17}\cdot L_{\mathrm{thirty}}+R_8{R}_{17}\cdot R_{21}\cdot C_{\mathrm{eighteen}}=0(8)$$

$$\begin{array}{l}{A}_3=R_8\cdot R_{17}\cdot R_{21}\cdot R_{23}\cdot L_{\mathrm{thirty}}\cdot C_{\mathrm{eighteen}}+R_8\cdot R_{17}\cdot R_{21}\cdot R_{31}\cdot L_{22}\cdot C_{\mathrm{eighteen}}+R_8\cdot R_{23}\cdot L_{22}\cdot L_{\mathrm{thirty}}-\\ -R_{17}\cdot R_{19}\cdot R_{23}\cdot R_{31}\cdot L_{\mathrm{thirty}}\cdot C_{\mathrm{eighteen}}-R_{17}\cdot R_{31}\cdot L_{22}\cdot L_{\mathrm{thirty}}=0.(9)\end{array}$$

From them, a reference is taken to the values of the desired parameters.

After all n stages of balancing are completed, the bridge is not brought to complete equilibrium, but n equilibrium conditions (n equations) are obtained, from which, as you know, we can take the count of n desired parameters of the two-terminal objects of measurement. Here at the output of the bridge at the beginning of the pulse there is a voltage surge that damps to zero during the transition process, and the voltage of the flat peak is zero.

After the end of the pulse during the transient process, a surge in voltage is also observed, which decays to zero. Such bridge circuits are quasi-balanced bridges.

Thus, in the given bridge meter of the parameters of n - element bipolar, the functionality is significantly expanded, and it allows you to determine the parameters R-L-C, R-L and R-C of n-element bipolar measurement objects, where the number n of measured parameters can be five, six, etc. At the same time, such an important property of the bridge chain as separate balancing is preserved.

It makes it possible to increase the number n of the determined parameters of measurement and control objects.

Claims (1)

A bridge meter of parameters of n-element two-terminal circuits, containing a pulse generator, which consists of pulse shapers with voltage changes over their duration according to the law k ₀ t ⁰ , k ₁ t ¹ , k ₂ t ² , ..., k _n-1 t ^{n- 1} (where k ₀ , k ₁ , k ₂ , ... are constant coefficients, t-time, n-number of elements in the two-terminal network of the measurement object or in its equivalent circuit), a switch, the inputs of which are connected to the outputs of the pulse shapers, and the output is connected to power amplifier, the output of which forms the first output relative to the "ground" of the imp pulses, synchronization unit, the output of which is connected to the synchronization inputs of the pulse shapers, as well as its output forms a second output relative to the "ground" of the pulse generator (synchronization output), the common bus of the pulse generator is grounded; the first output of the pulse generator is connected to the input of the four-armed electric bridge, the first branch of which includes two terminals for connecting two-terminal measuring objects and a single resistor, its first terminal is connected to the first output of the pulse generator, and the free output of a single resistor is connected to ground , the common output of the second terminal and a single resistor forms the first output terminal of the bridge circuit, parallel to the first branch of the bridge circuit its second branch is included, it includes serially connected two two-terminal, the common terminal of which forms the second output terminal of the bridge circuit, the second two-terminal is multi-element and consists of series-connected first resistor and the first inductive coil, the free terminal of the first resistor is connected to the common terminal of two two-terminal of the second branch of the bridge, and the free terminal of the inductive coil grounded, from a series-connected capacitor and a second resistor, the free terminal of the capacitor is connected to the common terminal of the first resistor and ind su- coil; a null indicator, to the differential input of which two outputs of the bridge circuit output are connected, to the synchronization input is the second output of the pulse generator, the common bus of the null indicator is grounded, characterized in that an additional resistor, an additional inductive coil and build-up circuits are introduced into it, and the second branch of the bridge circuit, the two two-terminal networks are the same in terms of the number of elements, their composition and inclusion, an additional (third) resistor is connected in parallel with the first inductive coil of the second multi-element two-pole nickname of the second branch of the bridge circuit, an additional (second) inductive coil is included in the second multi-element bipolar of the second branch of the bridge between the free terminal of the second resistor and ground, the additional (third) resistor, capacitor, second resistor and additional (second) inductive coil form an extension circuit , the total number of identical extension chains is equal to the quotient of dividing (n-2) by four [(n-2) / 4], if the quotient of the division is an integer, and the last extension circuit is complete if the quotient Since the division contains the integer and fractional parts, the number of build-up circuits is equal to the integer plus one, and the last build-up circuit is incomplete and consists of an additional (third) resistor, capacitor and second resistor, while the free output of the second resistor is grounded, or the last build-up circuit consists of an additional (third) resistor and capacitor, and the free terminal of the latter is grounded and, finally, the last extension circuit is only one additional (third) resistor, the total number of ementov second two-terminal network of the second branch of the bridge is the number of elements in the two-terminal network measurement object, each subsequent chain extension second, third, etc. it is connected parallel to the inductive coil of the previous build-up circuit; the number of formers in the pulse generator is equal to the number of elements in the two-terminal network of the measurement object or in its equivalent circuit.