SU1224735A1 - Electricity meter - Google Patents

Abstract

The invention relates to electrical; roizmeritelnoy technology. The purpose of the invention is to increase measurement accuracy. The device contains a signal polarity switch 1, a multiplier 2, an inverting amplifier 3 DC, a switch 4, a capacitor 5, a voltage-frequency converter 6, a reversible counter 7, a counting trigger 8 and a limiting amplifier 9. The specified goal is achieved by introducing into the device DC inverting amplifier, switch, capacitor, counting trigger, amplifier-limiter and the formation of new connections between the elements of the device. 1 il. (L Yu to D: s SO e vykod

Description

The invention relates to electrical measuring equipment and can be used in the construction of AC electric-erg energy meters.

The purpose of the invention is to improve the measurement accuracy.

The drawing shows a flowchart of the counter.

The counter contains a switch

1 signal polarity, multiplier 2, inverting amplifier 3 direct current, switch 4, capacitor 5, voltage converter 6 voltage, reversible counter 7, circuit trigger 8 and limiting amplifier 9.

The input of the polarity switch 1 is the first input of the device, and the output is connected to the first input of the multiplier 2, the second input of which is the second input of the device. Multiplier output

2 is connected to the input of the inverting amplifier 3 constant current and to the first input of the switch 4. The output of the inverting amplifier 3 constant loop is connected to the second input of the switch 4, the outputs of which are connected to the terminals of the capacitor 5, and connected to the input of the converter

6 voltage-frequency, the output of which is connected to the counting input of the reversible counter 7, the sign input of which is connected to the control input of the signal polarity switch 1 and the output of the counting trigger 8, the counting input of which is connected to the output of the amplifier-limiter 9, the input connected to device input.

In addition, the output of the counting trigger 8 is connected to the control input of the switch 4, which changes the polarity of the connection of the capacitor 5 into feedback of the inverting amplifier 3 of direct current. The borrow and transfer outputs of the reversible counter 7 are the outputs of the device for counting the energy of the forward and reverse directions, respectively.

The arrangement works as follows.

The input signal is limited in amplitude by the amplifier-limiter 9 and is fed to the counting trigger 8, the output signal which changes the polarity of the signal at the output of the switch 1 of the polarity of the signal,

The coupling of the capacitor 5 to the feedback of the inverting amplifier 3 of the horizontal track using the switch 4 also changes the counting direction of the reversible counter 1 with a frequency equal to half the frequency of the input signal. In this case, the output current of multiplier 2 is the sum of the variable components and is determined by the formula

 6i xz ° a & "S SJBx, cos (Mt + 4) -R (wni) .00

 2i eK2 - Bx,: o5Cp-fi (cont) fK5, UexiUg 11k; so5

| J2Qt (i4i) a) if

yo

ABOUT)

ayh :;

and

where K is the transfer coefficient of the multiplier 2;

the output current of the multiplier 2;

yi, device input voltages;

M is the frequency of the input signals; Cf - phase shift between input

signals; t is the time

S ("nt), t (2,4-l), n-whole-I, () f.a) t. (2,2) ir, n whole J

KCwnt) - Rademacher Function (Meander)

with frequency (U;

U is the frequency of the switch of the signal carrier;

K-i-U is the decomposition coefficient of the function R () in the Fourier series; , l, 2, ..., M.

The first term in (I) is useful and determines the average power, and the second determines the current variations at the output of multiplier 2. The analysis of the second term (l) subject to

4S

Wr

shows, that in the sum of the combination frequencies there are no beats with cha.

jg slots close to y, which is one of the reasons for the occurrence of variations.

The inverting amplifier 3 DC: with a capacitor 5 in the SSC connection in each half-period of the signal from the counting trigger 8 is an active KS filter, which by switching the polarity of the connection of the capacitor 5 passes a change to the output of the base. The component of the signal and in (2i + l) suppresses all the others (where K is the transmission coefficient of the RC filter. Thus, the voltage-frequency at the input of the converter 6 is determined by the formula

Ueb, () Uex, UBMC054

00 Kico5 {tot (2,4i) |)

 , Ir,,

.ilfj R C5H (2)

where E is the resistance of the feedback circuit of the inverting amplifier 3 of direct current; Cj is the capacitance of the capacitor 5. The pulses, whose frequency is proportional to the useful component, from the output of the converter 6, the voltage-frequency is fed to the input of the reversible counter 7, where they accumulate with the sign determined by the state of the counting trigger 8, and the frequency of the pulses from the outputs the borrowing and transfer of the reversible counter 7 is proportional to the power of the forward and reverse directions, respectively. Using the invention allows to significantly improve the measurement accuracy by completely eliminating the variations associated with and signal frequencies and signal switching frequencies, reducing the variations associated with the component of the doubled signal frequency, c) / k (2i) times, where K (2co) is the BS-filter transfer coefficient at the DC inverter 3 and konden Compiler S.Kabikov Editor N. Volovik Tehred N. Bonkalo

Order 1947/45 Circulation 728 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, 4/5

11production and printing company, Uzhgorod, st. Project, 4

12247354

Sator 5 at a frequency equal to twice the frequency of the signal.

Claims (1)

Invention Formula five An electricity meter comprising a signal polarity switch, a multiplier, a voltage-frequency converter and a reversible counter, wherein the input of the signal polarity switch is the first input of the device, its output is connected to the first input of the multiplier whose second input is The second input of the device, the output of the voltage-frequency converter, is connected to the counting input of the reversible counter, the sign input of which is connected to the control input of the signal polarity switch, and the output is the output of the device, characterized in it is additionally introduced an inverting DC amplifier, a switch, a capacitor, a counting trigger and a limiting amplifier, the input of an inverting DC amplifier connected to the output of the multiplier, and the output to the input of a voltage-frequency converter, the input of the switch are connected respectively to the input and output of the inverting amplifier direct current, the outputs to the corresponding terminals of the capacitor, and the control input of the switch is connected to the control input of the signal polarity switch and to the output of the counting trigger, Air input of which through the limiting amplifier. Connected to one of the device inputs. Proofreader E, Sirohman