SU1167512A1 - Device for separating direct component of variable voltage - Google Patents

Abstract

A DEVICE FOR ISOLATING A CONSTANT COMPONENT AC Voltage, containing the first and second integrators, the signal inputs of which through the first and second keys are connected respectively to the common input of the device and the output of the reference rail source, the control bus connected to the corresponding terminals of the control inputs of both keys, a reset bus connected to the corresponding terminals of the reset inputs of both integrators., characterized in that, in order to improve accuracy, a comparator is entered into it, the exponential the converter and the third key, and the second key is made two-way, with the inputs of the comparator connected to the outputs of the integrators, and the output to the control input of the exponential transducer, the third key connected to the circuit between the output of the reference voltage source and the power input of the ex-3 Potential converter, One TL from the control input terminals of the third key is connected to the control bus, and an additional section of the second switch is connected between the input and output of the second integrator.

Description

The invention relates to electrical measuring equipment and is intended for use in monitoring average values of signals, for example, in installations of technical diagnostics of various industrial facilities by the spectral composition of noise and vibrations.

A device for isolating a constant voltage component comprising a series-connected integrator, a key and a non-linear converter, the control inputs of which are connected to the corresponding outputs of the control unit J, is known.

The disadvantage of the known device is associated with low accuracy, due to the impossibility of using the initial part of the characteristic of a nonlinear converter, which, by its nature of change, approaching the hyperbolic, is located in this area in the region of infinitely large values.

Closer to the present invention is a device for constant-voltage splitting of a variable voltage containing first and second integrators, the signal inputs of which through the first and second keys are connected respectively to the common input of the device and the output of the reference voltage source with integrator outputs, a control bus connected to the corresponding terminals of the control inputs of both keys, a reset bus connected to the corresponding terminals of the reset inputs of both integrates tori 2 J.

The disadvantage of this device also appears to be of low accuracy due to errors inherent in the analog block, division, and instability of the parameters of the latter.

The aim of the invention is to improve the accuracy of the measuring device.

The goal is achieved by the fact that a device for isolating a DC component of an alternating voltage, containing the first and second integrators, the signal inputs of which through the first and second keys are connected respectively to the common input of the device and the output of the reference voltage source, the control bus connected to the corresponding terminals of control inputs of both keys, bus

reset, connected to the corresponding terminals of the reset inputs of both integrators, entered a comparator, an exponential converter and a third key, and the second key is two-way, with the inputs of the comparator connected to the outputs of the integrators, and the output to the control input of the exponential converter, the third key is included in the circuit between the output of the reference voltage source and the power input of the exponential converter; one of the terminals of the control input of the third key is connected to the control bus, and an additional second switch sections included in the circuit between the input and output of the second integrator.

and FIG. t is a functional diagram of the proposed device for isolating a constant component of an alternating voltage; in FIG. 2, time diagrams of signals illustrating the operation of the device.

The device contains integrators 1 and 2 (Fig. 1), electronic switching switches 3-5, of which key 4 is on-off, reference voltage source 6, comparator 7, exponential converter 8, control bus 9, reset bus 10. Integrators 1 and 2 comprise, respectively, large-scale resistors 11 and 12, operational amplifiers 13 and 14, feedback capacitors 15 and 16, and electronic discharge switches 17 and 18. The exponential converter 8 consists of a capacitor 19, in parallel with which The dongle 20 includes a resistor 21. The signal inputs of the integrators 1 and 2 through the switch 3 and one of the switch sections 4 are connected to the common input of the device and the output of the source 6 of the reference voltage, respectively, and to the inputs of the comparator 7. The output of the comparator 7 is connected to y the control input of the exponential converter 8 (to the control input of the bit switch 20). The key 5 is included in the circuit between the output of the source 6 of the reference voltage and the power input of the exponential converter 8. The control bus 9 is connected to the corresponding terminals of the control inputs of the switches 3-5, the reset bus 10 is connected to the corresponding terminals of the reset inputs of the integrators 1 and 2 (control 31 the firing inputs of the bit keys 17 and 18). Another section of the key 4 is included in the circuit between the input and output of the integrator 2. The device operates as follows. Let the input signal of the device receives the ID (figa). In the initial state, the voltage U (Fig. 26) of the logic unit is set on the reset bus 10, and the voltage Od (Fig. 2c) of the zero level is set on the control bus 9. The bottom section of key 4 is closed, keys 3 and 5 are open. Voltages at the outputs of the integrators 1 and 2 are absent (in the example of the implementation of integrators 1 and 2, the absence of voltages at their outputs is ensured, for example, by closing the discharge switches 17 and 18). The exponential transducer 8 is in the storage mode of the previous measurement result (this mode is provided, for example, by opening the bit 20). At the point in time, which characterizes the end of the pre-stage preparation stage, the measurement level, the voltage level of the reset bus 10 changes from a logical one to a logical zero. The bit switches 17 and 18 are open, however, the voltage at the outputs of the integrators 1 and 2 remains zero. At a time t, the control bus 9 is supplied with a control pulse Ug of a logic unit level, which is fed to the control inputs of keys 3-5. During the operating time of the control pulse Od with the duration T - fcj, the upper section of the key i 4 is closed, the keys 3 and 5 are closed. From the moment of time i, the signal under study and,, arriving at the input of the integrator 1, is integrated last, as a result of which the voltage (Fig. 2d) at the output of the integrator 1 does not change according to the expression

.. one

U, .Ugdt

0) 1; - the integrator integration constant 1, defined 55 as t 3 R Q, where. 1 is the resistance of the scale resistor 11;

. , + T

(h) 4

Us lU, c.t K, U,

СЯ 12 C, j - capacitor capacitance 15, b - time counted from the moment -t. The voltage U to the output of the integrator 2 from time t varies linearly in accordance with the expression LJ —the integration integrator constant 2, defined as 0 g as t – j K, where R., is the scale resistance — r rr f frrry of resistor 12; - capacitor capacitance 16 and - reference voltage at the output of source 6. Voltages (i, 0 from the outputs of the integrators 1, 2 are fed to the corresponding inputs of the comparator 7. When the condition is met, Uj Сз at the output of the comparator 7 appears voltage U - (Fig.2.3) level of logical unit. From time point -t to time point t, the output voltage (J / h SFG.2) of the exponential converter 8 is equal to the reference voltage of source 6, coming through the closed key 5. Ex. U, formed by comparator 7, closes bit 20 and introduces an ex Potential converter 8 to preparatory mode. When the control pulse expires (Jg at time point -tg, keys 3 and 5 open, and key 4 switches to the initial state with closed lower section. At time moment i, voltage U of the output of integrator 1 is equal to the value of the integral of the voltage of the signal 1) with the time T of the averaging K. Tr - the coefficient of proportionality.At the moment of time -t, the voltage Uj at the output of the integrator 2 is determined by the value of the coefficient of proportionality. From the time point -tj during the whole subsequent time of the stress and remains unchanged and equal to and (tj 1, and the voltage O varies according to the expression Ml) U-ia) 2 () (i3) At time 4, the voltage on the inputs comparator 7 is compared (Vt3). r And at subsequent times, the voltage and its output is set at the level of logical zero. In this case, the bit key 20 opens with. After unlocking key 5 at time i ,, and before unlocking key 20 at time point -t (in the time interval r5 (), the capacitor 19 of the exponential converter 8 is discharged through the resistor 21 and the locked key 20 exponentially ( 12 t is the time constant of the circuit where the capacitor 19 is discharged, defined as where Rji is the resistance of the resistor 21; C, d is the capacitance of the capacitor 19, By the time i U reaches the value (,). A new measurement cycle, since the keys 5 and 20 after the moment i are open It can be shown that when C; 2 is equal, the voltage Ug (, J is the selected constant value of the alternating voltage t / g during time T of averaging 8 (t / i If necessary, the constant component of the alternating voltage: For another time of averaging or performing a new cycle of averaging a signal in another time interval, the output voltages of integrators 1 and 2 are reset by applying a reset unit level pulse to bus 10 at time t. The increased accuracy in the distribution of the constant component of the alternating voltage by the proposed device is ensured by the absence in its design of an unstable analog dividing unit.

Claims (1)

A device for isolating a constant component of alternating voltage, containing the first and second integrators, the signal inputs of which are connected through the first and second keys to the device common input and the voltage reference source output, a control bus connected to the corresponding terminals of the control inputs of both keys, the bus' reset connected to the corresponding terminals of the reset inputs of both integrators., characterized in that, in order to improve accuracy, a comparator, an exponential the browser and the third key, and the second key is made on-off, with the comparator inputs connected to the outputs of the integrators, and the output to the control input of the exponential converter, the third key is connected to the circuit between the output of the reference voltage source and the power input of the ex--3 potential converter, one of the terminals of the control input of the third key are connected to the control bus, and an additional section of the second key is connected to the circuit between the input and output of the second integrator. £ 2 □ 5 Joint venture KZ 1 167512