SU1465796A1 - Digital meter of a.c. power - Google Patents

Abstract

The invention can be used in digital power meters with analog signal multiplication. The purpose of the invention is to increase the measurement accuracy. The digital meter contains input converters 1 and 2 of voltage and current, analog multiplier 3, analog averager 4, and analog-digital pre. educator 5. Introduction szp 1matorov. 6 and 7, integrator 8, digital quad 9, phase inverter 10, and the formation of new functional relationships eliminates the influence of the multiplicative component of the multiplier conversion function on the measurement result. 1 il. -. with (L

Description

X iU) J dt 0 From here

F

formula of invention

and

Bliic

 VK, -K.UU) -i (t).

(five)

Voltage (5) is measured using an analog-to-digital converter 5 N Kdzr and jt,;, with a transfer coefficient Kdz, and the code of the number N is quadri- vated in digital quadrant 9. Code

 LCP

the numbers at its output N f X P, with K / inn K, -K multiple of ten, is proportional to the value of active power P and does not depend on the value of the transmission coefficient K of the analog multiplier 3. Independence of the result Np K cp-K, K, -P measurements from the transmission factor value K to analog multiplier 3 opens up the possibility of increasing the accuracy of power measurement even in the case of using semiconductor voltage multipliers (Hall sensors),

Thus, the proposed digital variable voltage power meter allows to increase the power factor. I HocTb measurements of digital power meters with analog signal multiplication by eliminating the influence of the multiplicative component

0 Z5

0

A digital AC power meter containing an input voltage converter, an input current converter, an analog multiplier, an analog averager whose output is connected to the input of an analog-to-digital converter, so that In order to improve measurement accuracy, it additionally introduced two adders, an integrator, a digital quad and a phase inverter, whose input is connected to the input of the analog average, with the integrator's output and with the subtracting input of the first adder, summing its input is connected to the output of the current converter, and the output is connected to the first input of the analog multiplier, whose output is connected to the integrator's input, the second input of the analog multiplier is connected to the output of the second adder, the totalizer input of which is connected to the phase inverter output, the subtracting input is connected to the output of the input field is voltage bodies, and the input of the digital J quad is connected to the output of the analog-digital converter.

Claims (1)

Claim A digital AC power meter containing an input voltage converter, an input current converter, an analog multiplier, an analog averager, the output of which is connected to the input of an analog-to-digital converter, characterized in that, in order to improve the measurement accuracy, two adders are additionally introduced into it, an integrator, a digital quadrator and a phase inverter, the input of which is connected to the input of the analog averager, with the output of the integrator and with the subtracting input of the first adder, summing the input of which connected to the output of the input current converter, and the output is connected to the first input of the analog multiplier, the output of which is connected to the input of the integrator, the second input of the analog multiplier is connected to the output of the second adder, the summing input of which is connected to the output of the phase inverter, the subtractive input is connected to the output of the input voltage converter, and the input of the digital quadrator is connected to the output of the analog-to-digital converter.