RU2092861C1 - Method of measuring the impedance parameters and device intended for its realization - Google Patents

Abstract

FIELD: measuring equipment. SUBSTANCE: method and corresponding device enable simultaneous measurement of active and reactive components of impedance, for example of two-terminal networks having electromotive force between terminals which is constant or slowly variable in time, as well as of objects containing electrolytes. Device circuit includes generator, measuring circuit containing impedance being measured, filter, controlled integrator, and control pulse forming unit. EFFECT: enhanced measurement speed. 2 cl, 6 dwg

Description

 The invention relates to the field of electrical engineering, in particular to the measurement and control of components of the impedance, including the invention is suitable for measuring the impedance of objects containing electrolytes.

где V суммарное напряжение на зажимах цепи делителя;
V_o падение напряжения на образцовом сопротивлении;
R_oбр величина образцового сопротивления;
R_g входное сопротивление вспомогательной измерительной цепи;

модуль искомого комплексного сопротивления.A known method for determining the complex resistance (ed. St. USSR N712777, class MKI GO1-R27 / 00, 27/02, 1980). This method consists in the fact that the voltage is measured at the terminals of the divider circuit, consisting of series-connected reference and measured resistances, as well as at the reference and measured resistances. The module and the angle of the measured complex resistance are determined by their values, and the voltage at the model resistance is measured by pre-connecting an auxiliary circuit with an active input parallel to it, and the angle of the desired complex resistance is calculated by the formula:

where V is the total voltage at the terminals of the divider circuit;
V _o the voltage drop across the model resistance;
R _{is the} magnitude of the model resistance;
R _g input resistance of the auxiliary measuring circuit;

the module of the desired complex resistance.

 The known method for determining the complex resistance is implemented in a circuit that contains an alternating voltage source 1, series-connected reference resistor 2 and the desired complex resistance 3, a measuring circuit consisting of series-connected active resistances 4 and 5 of the divider, and a voltmeter 6. Resistance 4 and 5 the measuring circuit is connected in parallel to a small resistance 4 of the divider circuit.

The disadvantages of the known method for determining the complex resistance and circuitry for its implementation are:
low speed;
the impossibility of carrying out operational measurements;
the impossibility of measuring the complex resistances of objects containing electrolytes.

Closest to the technical nature of the present invention are a method and a circuit for measuring the impedance of the sensor (application EPO N 0065675, class MKI GO1 R27 / 02, 27/26, 27/22, 1982). This method consists in the fact that the first sinusoidal voltage U1 and the rectangular voltage U2 are synchronously generated, then the first sinusoidal voltage U1 is supplied to a measuring circuit having a measured impedance Z _x , the output of which appears a second sinusoidal voltage U3 proportional to the impedance Z _x . This voltage is filtered off and phase shifted so that the voltage U5 obtained as a result of this operation passes through zero simultaneously with the rectangular voltage U2. After that, the voltage U5 is detected during the positive half-cycle, and during the negative half-cycle it is shorted to ground, this process is synchronized by the rectangular voltage U2. As a result of the above operations, a constant voltage U _dc proportional to the measured impedance Z _{x is} obtained.

 The circuit implementing this method includes a generator 1, the first output of which is connected to the input of the measuring circuit 2, connected in series with the filter 4, the output of which is connected to the first input of the rectifier circuit 3, the second input of which is connected to the second output of the generator 1, and the output is the output devices.

The disadvantages of the closest in technical essence to the proposed invention method and scheme are:
measuring only the module of the active component of the impedance;
low speed due to the need to isolate a constant component and, as a consequence, the impossibility of measuring the impedance, changing in time with a speed comparable to the time constant of the rectifier circuit 3.

When creating the proposed method for measuring the parameters of the impedance and the device for its implementation, the following tasks were solved:
simultaneous (with a shift of one or two periods of the operating frequency) measurement of the active and reactive components of the impedance, including dvukhpolosnykh having between the poles of the EMF, constant or slowly changing in time, as well as objects containing electrolytes;
an increase in the measurement speed compared with known methods, which allows the measurement of the impedance slowly varying in time (slowly compared to the period of the signal with which measurements are made).

Problem solving is as follows. At the outputs of the generator, sinusoidal and rectangular voltages are simultaneously generated, and a sinusoidal voltage is supplied to a measuring circuit containing the measured impedance Z _x . The output of the measuring circuit receives a voltage proportional to the impedance module Z _x and with a phase shift relative to the sinusoidal voltage generated at the generator output equal to the phase shift of the impedance (phase shift between voltage and current in the circuit whose total resistance is measured), which is then filtered and served on a controlled integrator, where it is integrated over a period, and during one half-cycle, the integration process is carried out without changing the sign of the integrable tension, and during the other with a change in its sign to the opposite, in this case, to measure the active component of the impedance, the integration process begins at the moment the sinusoidal voltage at the output of the generator passes through zero, and to measure the reactive component when the absolute value reaches its maximum value voltage. As a result of integration at the output of the controlled integrator, alternately (the sequence can be any), signals proportional to the values of the active and reactive components of the measured impedance are formed (signals at the integrator output mean a set of measurements of the state of any physical information carriers, voltage, current, encoded sets of pulses, potentials etc.) which are then remembered.

The integration process and memorization are controlled as follows. The rectangular and sinusoidal voltages at the generator outputs are synchronized in such a way that the edges and slices of the rectangular voltage coincide with the moments when the sinusoid passes through zero and is fed to the control signal generation unit, which generates resolution and integration sign signals, as well as a signal to record the integration results into the memory unit. All output signals of the control signal generating unit are synchronous with the sinusoidal voltage of the generator, since formed from rectangular. The integration enable signal in duration is equal to the generator voltage period and its beginning coincides in the mode of measuring the active component of the impedance with the transition of the sinusoidal voltage of the generator through zero, in the mode of measuring the reactive component of the impedance with the maximum absolute value of the same voltage (i.e., with a shift of 90 or 90 ^o in phase relative to the previous one).

 The signal of the integration sign starts and ends simultaneously with the integration enable signal, and in the first half of its duration, it sets the integration mode in the controlled integrator without changing the sign of the integrated voltage, and during the other with the opposite sign (or vice versa).

The integration enable signal, the controlled integrator is alternately included in the measurement mode of the active and reactive components. At the same time, a signal proportional to
U _m • sinΦ,
and in the active component measurement mode, the signal is proportional
U _m • cosΦ,
where U _{m the} amplitude of the voltage at the output of the measuring circuit, proportional to the module of the measured impedance;
Φ phase shift of the measured impedance, i.e. these signals are proportional to the components of the measured impedance.

 After the end of each of the integration modes, the signals from the output of the integrator are recorded in the memory block by the recording signal from the shaper of control signals.

The essence of the proposed method for measuring the impedance is confirmed by the following calculation. By definition, the sinusoidal voltages at the output of the generator (U1) and at the output of the filter (U4) are of the form
U ₁ = U _1m • sinΦ and U ₄ = U _4m • sin (Φ-Φ _x ),
where Φ = ωt;
ω angular frequency;
t time
F _x phase shift of voltage U4 relative to U1.

где а1.а3 пределы интегрирования.Integrate voltage U4. The integration enable signal, turning the integration process on and off, thereby sets its limits 0.2n or n.3n in the active component measurement mode and n / 2 5n / 2 or 3n / 27n / 2 in the reactive component measurement mode. Since the sign of the integration sign changes the sign of the integrated voltage, the integral can be represented in the form of two terms

where a1.a3 integration limits.

Here, a constant component U _o is introduced into the calculations, which in the general case may be present at the output of the measuring circuit simultaneously with the main sinusoidal signal. Since the intervals (a2-a1) and (a3-a2) are equal and integration into them is performed with the opposite sign (by the initial definition), its presence does not affect the result. Obviously, substituting the limits into the integral gives the following integration results: in the measurement mode of the active component U _a = 4 • U _4m • cosΦ _x , in the measurement mode of the reactive component U _r = 4 • U _4m • sinΦ _x . But, because U4 _{m is} proportional to the modulus of the impedance, and Ф _x is equal to the phase shift of the impedance, the integration results U _a and U _{r are} proportional to the active and reactive components of the impedance, respectively. Thus, the following signals appear at the output of the controlled integrator: U _a proportional to the active component of the impedance Z _x , and U _r proportional to the reactive component of the impedance Z _x , depending on the integration mode.

 The use of controlled integration during the period of the sinusoidal voltage at the generator output with a shift in its beginning allows us to measure both the active and reactive components of the impedance and, in addition, reduces the minimum necessary “pure” measurement time of each of the components to one generator voltage period, t. e. increases the performance of meters using the proposed method. A change in the sign of integration in the middle of the interval compensates for the components in the output signal that change little during the period of the sinusoidal voltage of the generator and, therefore, excludes the influence of such effects on the inputs of the measured bipolar and on the measurement results. In particular, this applies to induced EMF from interference and from various electrochemical processes, if they occur in devices included in the measured circuit.

 Figure 1 is a diagram of a device for measuring the impedance; FIG. 2 is a timing diagram of the operation of the impedance measuring device of FIG. 3 circuit analog controlled integrator; figure 4 diagram of a wide-range multiplexer; figure 5 diagram of a three-mode integrator; in FIG. 6 is a timing diagram of the operation of an analogue controlled integrator.

The circuit of the device that implements the proposed method of measuring the impedance contains a generator 1, the first output of which is connected to the input of the measuring circuit 2, containing the measured impedance Z _x , the output of which is connected in series through a low-pass filter 3 with the first input of the controlled integrator 4, the second and third the inputs of which are connected to the same outputs of the control signal generation unit 6, connected by its input to the second output of the generator 1, and the first output to the second input of the memory unit 5, the first input of which is connected to the output of the integrator 4-managed and the output is the output of the circuit.

The measurement of the impedance of the proposed method is as follows. The outputs of the generator 1 synchronously generate a sinusoidal (U1) and rectangular voltage (U2) (figure 2). These voltages are synchronized so that the edges and slices of the rectangular voltage (U2) coincide with the moments when the sinusoidal voltage (U1) passes through zero. A sinusoidal voltage is supplied to the measuring circuit 2, containing the measured impedance Z _x . The output of the measuring circuit 2 receives a voltage (U3) proportional to the measured impedance module Z _x and with a phase shift relative to the sinusoidal voltage U1 equal to the phase shift of the measured impedance Z _x (phase shift between voltage and current in the circuit whose impedance is measured) . The voltage U3 is then filtered and a sinusoidal voltage U4 is obtained (FIG. 2). This voltage is supplied to a controlled integrator 4, where it is integrated during the period, and the integration process is divided into two equal parts and during one of them is integrated without changing the sign of the integrated voltage, and during the other, changing to the opposite. In this case, integration begins at the moment of crossing the voltage U1 through zero to measure the active component and at the time of reaching the maximum value in absolute value of the same voltage (i.e., with a phase shift of 90 or 90 ^o relative to voltage U1) to measure the reactive component of the total resistance Z _x . As a result of integration at the output of the controlled integrator 4 in turn (the sequence can be any), signals proportional to the values of the active and reactive components of the measured impedance Z _x are obtained (signals at the output of the integrator mean a set of state changes of any physical information carriers: voltage, current, encoded sets pulses, potentials, etc.), which are then stored in the memory unit 5.

The process of integrating the sinusoidal voltage U4 and storing the signals obtained as a result of integration is controlled as follows. The rectangular voltage U2 from the output of the generator 1 is supplied to the control signal generation unit 6, which generates integration resolution and sign signals, as well as a signal for recording the integration results in the memory unit. All output signals of the control signal generating unit 6 are synchronous with the sinusoidal voltage U1, since are formed from the rectangular voltage U2. The duration integration integration signal is equal to the voltage period U1 and its beginning coincides in the mode of measuring the active component of the impedance with the transition of the sinusoidal voltage of the generator through zero, in the mode of measuring the reactive component of the impedance with the maximum absolute value of the same voltage (i.e., with a shift of 90 or 90 ^o in phase relative to the previous one).

 The signal of the integration sign begins and ends simultaneously with the integration enable signal, and in the first half of its duration, it sets the integration mode in the controlled integrator without changing the sign of the integrated voltage, and during the other with the opposite sign or vice versa.

The integration enable signal controlled by the integrator 4 is alternately included in the measurement mode of the active and reactive components. At the same time, at its output, in the reactive component measurement mode, a signal U _r proportional
U _m • sinΦ,
and in the measurement mode of the active component, the signal U _a proportional to
U _m • cosΦ,
where U _{m the} amplitude of the voltage at the output of the measuring circuit, proportional to the module of the measured impedance;
Φ phase shift of the measured impedance;
i.e., these signals are proportional to the components of the measured impedance.

 After the end of each of the integration modes, the signals from the output of the integrator by the recording signal from the shaper of the control signals 6 are recorded in the memory unit 5.

The values of the signals U _a and U _r stored in the memory unit 5 can be used to indicate the values of the active and reactive components of the measured impedance, further processing in a computer, microprocessor, or as control signals.

A diagram of a device that implements the proposed method for measuring the impedance parameters (Fig. 1) contains a generator 1, a measuring circuit 2 containing a measured impedance Z _x , a low-pass filter 3, a controlled integrator 4, a memory unit 5, and a control signal generating unit 6. The first output of the generator 1, designed to generate a sinusoidal voltage U1, is connected to the input of the measuring circuit 2, the output of which is connected in series through a low-pass filter 3 with the first input of the controlled integrator 4, serving to supply integrated voltage. The second and third inputs of the controlled integrator 4, which are the control inputs, are connected to the outputs of the same block of the formation of control signals 6, of which the second is used to generate the integration enable signal (U _p ), and the third to generate the integration sign signal (U _s ). The input of the control signal generating unit 6 is connected to the second output of the generator 1, which serves to form a rectangular voltage U2, and the first output with the second (control) input of the memory unit 5. The first input of the memory unit 5 is connected to the output of the controlled integrator 4, and the output is the output of the device .

Managed integral 4 can be implemented both digitally and analogously. An example of constructing an analogue controlled integrator 4 is shown in the diagram of FIG. 3. The circuit of the analogue controlled integrator 4 contains a wide-range multiplexer 7 [1, p. 283] shown in Fig. 4 a three-mode integrator 8 [ibid., P. 143] shown in Fig. 5, a delay line 9 and a one-shot 10. The first and second inputs connected to the broadband multiplexer 7 and are connected to a first input of an analog integrator managed 4. The control input of the broadband multiplexer 7 (indicated in the diagram of FIG. 3 U _Ctrl.) is the third input of the analog integrator managed 4, and its third and fourth inputs grounded . The second input of the analogue controlled integrator 4 is connected to the input S1 of the three-mode integrator 8 and sequentially through the delay line 9 to the input of the one-shot 10, the output of which is connected to the input S2 of the three-mode integrator 8. The first input of the three-mode integrator 8 is connected to the output of the wideband multiplexer 7, and its output is output of analogue controlled integrator 4.

 Block forming control signals 6 can be built, for example, on digital logic circuits.

 The memory unit 5 can be built, for example, on registers, RAM, etc. if a digital controlled integrator is used, or on sampling-storage schemes, if an analog controlled integrator is used.

A circuit that implements the proposed method for measuring the impedance parameters works as follows. At the first output of the generator 1 (Fig. 1), a sinusoidal voltage U1 is formed and, simultaneously with it, at the second output, a rectangular voltage U2 (timing diagram, Fig.2). The voltage U1 from the first output of the generator 1 is supplied to the input of the measuring circuit 2 having a measured impedance Z _x . The voltage U3 proportional to the measured impedance Z _x appears at the output of the measuring circuit 2, which is filtered out in the filter 3. The output voltage of the filter 3 U4 is supplied to the first input of the controlled integrator 4. The control signal generating unit 6 generates signals U _p , U synchronously with the voltage U2 _s and U ₃ , controlling the operation of the controlled integrator 4 and the memory unit 5 (Fig. 2): U _p integration enable signal U _s - signal specifying the sign of the integrated voltage; U ₃ signal recording information by the memory unit 6, which is supplied to it from the output of a managed integrator 4.

Analog controlled integrator 4, the circuit of which is shown in figure 3, works as follows. The voltage U4 is supplied to the first input of an analogue controlled integrator 4 and from it to the first and second inputs of a wide-range multiplexer 7, the circuit of which is shown in Fig. 4. The signal U _{s is} supplied to the third input of the analogue controlled integrator 4 and from it to the control input of the wide-range multiplexer 7, the operation of which is described in [1, p.283,284] At the output of the wide-range multiplexer 7, the voltage U o is generated _. .

U _out. = U4 at U _s = 1B;
U _out. = U4 at U _s = -1B.

Voltage U _o from the output of the wide-range multiplexer 7, it is supplied to the first input of the tri-mode integrator 8, the circuit of which is shown in FIG. 5, and the operation is described in [1, p.143] The control of the three-mode integrator 8 is carried out by the signal U _p supplied to the second input of the analogue controlled integrator 4, and from it to the input S1 of the three-mode integrator 8, and the signal U _set. received at the input S2 of the three-mode integrator 8 from the output of the single-shot 10. The single-shot 10 is triggered by a slice of the signal U _p , delayed in the delay line 9 by the time until the cut-off of the signal U ₃ (time t ₁ in the time diagram, Fig. 6) and generates output signal U _set. according to the timing diagram of FIG. 6. Signal duration U _set determined by the time required to reset the tri-mode integrator 8.

The signal U _p controls the key S1 of the three-mode integrator 8, and the signal U _set. key S2, and a high level of the control signal corresponds to the closed position of the key. The signal U _p sets the three-mode integrator 8 into the integration mode (time t ₀ in the time diagram of Fig.6), and the signal U _set. in reset mode (time t ₂ in the time diagram of Fig.6). During the absence of signals U ₃ and U _set. the three-mode integrator 8 is in storage mode (keys S1 and S2 are open, time t ₁ in the time diagram in Fig. 6).

Thus, at the output of the three-mode integrator 8, which is the output of the analogue controlled integrator 4, signals are formed, U _a proportional to the active component of the impedance Z _x and U _r proportional to the reactive component, depending on the integration mode.

 The integration mode is set by the shaper of control signals 6, and the sequence of setting modes is determined by a specific task and can be any. We are considering the case of alternately setting the integration modes (figure 2).

The signals U _a and U _{r are} recorded in the memory unit 5 and stored there. The recording is controlled by the signal U ₃ supplied to the second input of the memory unit 5 from the first output of the shaper control signals 6.

List of references:
1. W. Titze, K. Schenk. Semiconductor circuitry.-M. World, 1982.

Claims (2)

 1. The method of measuring the parameters of the impedance, which consists in normalizing the first sinusoidal voltage, which is applied to the measured impedance, the output of which forms a second sinusoidal voltage proportional to the measured impedance module and with a phase shift relative to the first sinusoidal voltage equal to the base shift measured impedance, the second sinusoidal voltage is filtered, characterized in that the filtered second sinusoidal voltage They integrate during a period, moreover, during one half-cycle they integrate without changing the sign of the integrated voltage, and during the other half-cycle with a change in its sign to the opposite, in this case, to measure the active component of the impedance, the integration process begins at the moment of transition through the “0” of the first sinusoidal voltage, and for measuring the reactive component - at the time of reaching the maximum absolute value of the first sinusoidal voltage and the corresponding results Tats integration judged on the amount of active and reactive components of the measured impedance.  2. A device for measuring the impedance parameters, comprising a generator, the first output of which is connected in series to a measuring circuit containing the measured impedance, and a filter, characterized in that a controllable integrator, a memory unit and a control signal rationing unit, the input of which is connected to the second output of the generator, the second and third outputs to the same inputs of the managed integrator, the first input of which is connected to the output of the filter, and the output to the first input of the memory unit , The second input of which is connected to the first output unit generating control signals, and the output is an output device.

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