CN205725711U - Highly integrated digital integrator for squirrel cage type hollow-core current transformer - Google Patents

Abstract

A kind of highly integrated digital integrator for squirrel cage type hollow-core current transformer, including integrator hardware and software, described software uses the form of firmware embedding processor, described integrator hardware integration includes Integral Processing module and metering module, squirrel-cage current transducer signal is processed and integral operation by described Integral Processing module samples, AD, and the result after computing directly carries out electrical parameter metering by described metering module.Compared with analogue integrator, digital integrator stable performance, phase characteristic is excellent, by temperature drift and time drift parameter affected, substantially increase certainty of measurement；Carry out effective compensation for the unescapable direct current offset of analogue integrator, measurement error can be adjusted more accurately.And this practicality is novel for highly integrated digital integrator, and it further comprises the functions such as metering, therefore solves the problem that many devices in series measurements bring overlay error.

Description

Highly integrated digital integrator for squirrel cage type hollow-core current transformer

Technical field

This utility model relates to a kind of digital integrator, especially a kind of for squirrel cage type hollow-core current transformer Highly integrated digital integrator.Squirrel cage type hollow-core current transformer therein is based on electromagnetic induction principle A current measuring transformer of design, measures wide ranges, measures electric current greatly (from several amperes to tens of Wan An Training), it is mainly used in the measurement of the smelting using high power equipment short net electric currents such as (but not limited to) mineral hot furnace, converter.

Background technology

The squirrel cage type hollow-core current transformer designed based on electromagnetic induction principle is the ring-type of a kind of nonmagnetic core Coil, may be used for measuring at the electric current of annulus middle conductor, and owing to it has, the linearity is good, nothing The characteristics such as saturated, certainty of measurement is high, are the most gradually applied to the smelting using high power equipment such as mineral hot furnace, converter short The measurement of net electric current.The secondary voltage signal of squirrel cage type hollow-core current transformer coil output is primary current letter Number differential, therefore tested primary current signal must be restored by corresponding integral element.Traditional is long-pending Point link mainly uses analog integrator circuit to realize, and its principle is: carried out input analog amount by RC circuit Analog integration, generally uses a kind of RC integrating circuit that linear operational amplifier and RC feedback circuit realize.

As it is shown in figure 1, input signal flows on electric capacity C through feedback after resistance R1, the initial electricity of electric capacity C Amount is zero, charges to electric capacity C, and disconnected character short by the void of operational amplifier, empty obtains: (vi-0)/R=dQ/dt=C*d (0-vo)/dt, so vo=-1/ (RC) ∫ vdt..

But the resistance that analog integrator circuit uses, capacitor element are not ideal component, amplifier direct current offset, long-pending Divide leakage and loss, the time factor such as drift and temperature drift of other analog devices of electric capacity, all integral result can be produced Raw impact, thus cause integration that deviation occurs, reduce the accuracy of current transformer；It addition, analog integration The Feedback Design underaction of device, its detection signal is output as analog quantity, then accesses metering module, thus may be used New error can be introduced, and owing to current transformer requires that it needs long-time stable to work, overcome completely The error that these factors cause is the most difficult.

On the other hand, present overall measurement uses the mode of many devices in series, and the signal of big electric current needs Will be through squirrel cage type hollow-core current transformer, analogue integrator, analog signal isolating and metering module.Process In each link can produce measurement error, by final measurement result after multiple measurement error superpositions Causing bigger deviation, this overlay error is nonlinearity erron, will regulate this error the most extremely difficult.

In view of this, special proposition this utility model.

Utility model content

The technical problems to be solved in the utility model is to overcome the deficiencies in the prior art, it is provided that a kind of for Mus The digital integrator of cage air-core current transformer, is more specifically that one collects integration and function of measuring is one The highly integrated digital integrator of body.

For solving above-mentioned technical problem, the basic conception of this utility model employing technical scheme is:

A kind of highly integrated digital integrator for squirrel cage type hollow-core current transformer, including integrator hardware And software, described software uses the form of firmware embedding processor, and described integrator hardware integration includes amassing Divisional processing module and metering module, squirrel-cage current transducer signal by described Integral Processing module samples, AD processes and integral operation, and the result after computing directly carries out electrical parameter metering by described metering module.

Further, also including wave filter, the signal after described AD process is through described wave filter, by filter Described integral operation is carried out again after ripple.

Further, also provide for verifying the PC end software that error compensation parameter sets, by a serial line interface Communicate with PC.

Preferably, this digital integrator uses 32 high-speed CPUs to be module core, and IC processor uses ADE7858 computation chip.

Further, it is additionally provided with RS485 communication interface, by described RS485 communication interface by measured Data communication control to other required higher levels.

After using technique scheme, this utility model compared with prior art has the advantages that should For the digital integrator of squirrel-cage current transformer, overcome the deficiency of analogue integrator, it is achieved that once Current signal accurate reproduction.Compared with analogue integrator, digital integrator stable performance, phase characteristic is excellent, Not by temperature drift and time drift parameter affected, substantially increase certainty of measurement；Cannot be avoided for analogue integrator Direct current offset carry out effective compensation, measurement error can be adjusted more accurately.And this practicality is novel is Highly integrated digital integrator, it further comprises the functions such as metering, therefore solves many devices in series and measure band The problem carrying out overlay error.

Accompanying drawing explanation

Fig. 1 is RC integrating circuit figure；

Fig. 2 is schematic diagram of the present utility model.

Detailed description of the invention

Below in conjunction with the accompanying drawings and specific embodiment, the utility model is described in further detail, to help understanding this reality By novel content.

A kind of highly integrated digital integrator for squirrel cage type hollow-core current transformer, including integrator hardware And software, described software uses the form of firmware embedding processor, and described integrator hardware integration includes amassing Divisional processing module and metering module, squirrel-cage current transducer signal by described Integral Processing module samples, AD processes and integral operation, and the result after computing directly carries out electrical parameter metering by described metering module.

Cannot function as finally owing to being matched in the measurement signal of the analogue integrator of squirrel cage type hollow-core current transformer Variable, also needs follow-up measurement, and this utility model uses digital integrator to instead of analogue integrator, and will The device of higher degree is integrated in this integrator, such as Integral Processing module and metering module etc., i.e. uses collection Circuit is become to instead of analog circuit.

During work, input analog amount is carried out high-speed ADC and is converted to digital quantity, and utilize high-speed figure to process Device is integrated computing, and other similar products the most for another example of the result after computing are converted to analog quantity by DAC, But directly this result is carried out electrical parameter metering by integrated metering module, without middle DA and AD Process, therefore would not produce the error in transformation process, the most just solves many devices in series measurements and brings folded The problem adding error.

As in figure 2 it is shown, this utility model also includes wave filter, the signal after described AD process is through described filter Ripple device, by carrying out described integral operation again after filtering.

Increase wave filter, for eliminating the direct current signal biasing in signal, then when being integrated computing, permissible Reduce the direct current signal biasing impact on digital integrator precision, improve the overall accuracy of digital integrator.

This utility model also provides for verifying the PC end software that error compensation parameter sets, by a serial line interface Communicate with PC.

During squirrel cage type hollow-core current transformer measures the big electric current of mineral hot furnace, digital integration is used to process Realize during squirrel cage type hollow-core current transformer is measured amplitude, waveform, the regulating error of angle, by numeral The multiple spot error compensating method of integrator, improves the certainty of measurement of overall measurement apparatus.Specific as follows:

$e\left(t\right)=-M\frac{di}{dt}$

Output voltage e (t) of squirrel-cage current mutual inductor coil is proportional to the rate of change of tested electric current:

In above formula, M is mutual inductance between mutual inductor coil and a bus, and i is tested primary current.

By the output voltage of squirrel-cage current mutual inductor coil is integrated, restore tested current signal,

$i\left(t\right)=i\left(0\right)-\frac{1}{M}{\∫}_0^{t}e\left(t\right)dt$

That is:

By the adjustment to integral operation parameter, realize during squirrel-cage current transformer is measured amplitude, ripple Shape, the regulating error of angle, with the multiple spot error compensating method of digital integrator, improve overall measurement apparatus Certainty of measurement, it is thus achieved that the controlling of production process effect that measurement apparatus synthetic error is controlled.The benefit of integral error Repaying, including amplitude, phase angle, waveform separate compensation, compensation points is no less than 10 points, less than 20 Individual point.

There is provided the verification PC end software that error compensation parameter sets, it is ensured that many point tolerances of digital integrator The correctness of compensation method, meets the requirement of certainty of measurement.

This utility model uses 32 high-speed CPUs to be module core, and IC processor uses U.S. Analog The ADE7858 computation chip of Devices, Inc. company latest generation.

ADE7858 is a high accuracy, three phase electric energy measurement IC, uses serial line interface, this device built-in two Rank sigma-delta type ADC, digital integrator, reference voltage source circuit and all required signal processing circuits, I.e. fix function digit signal processor (DSP), can perform to process and measure various three lines, the three phase arrangement of four lines Meritorious, idle and apparent energy, such as Y shape or triangle etc.；Respectively it is respectively provided with system calibration function mutually, i.e. Virtual value offset correction, phase alignment and gain calibration.

Use 32 high-speed CPUs and ADE7858 computation chip, make this utility model have the most excellent property Can, its accuracy is higher, calculates speed faster, and General Promotion measures process efficiency.

Digital integrator is substituted original analogue integrator by this utility model, design its input and output interface with The interface compatibility of former analogue integrator, is additionally provided with RS485 communication interface, will by this communication interface Measured data communication controls to other required higher levels.Wherein without DA and AD process so that finally survey Accuracy of measurement is greatly improved.

The above is only preferred implementation of the present utility model, it is noted that for the art For those of ordinary skill, on the premise of without departing from this utility model principle, it is also possible to make some improvement And retouching, these improvements and modifications also should be regarded as protection domain of the present utility model.

Claims (6)

1. for a highly integrated digital integrator for squirrel cage type hollow-core current transformer, hard including integrator Part and software, described software uses the form of firmware embedding processor, it is characterised in that described integrator is hard Part is integrated with and includes Integral Processing module and metering module, and squirrel-cage current transducer signal passes through described integration Processing module sampling, AD process and integral operation, and the result after computing is directly carried out by described metering module Electrical parameter metering.

Highly integrated digital integration for squirrel cage type hollow-core current transformer the most according to claim 1 Device, it is characterised in that also include that wave filter, the signal after described AD process, through described wave filter, pass through Described integral operation is carried out again after filtering.

Highly integrated digital integration for squirrel cage type hollow-core current transformer the most according to claim 2 Device, it is characterised in that also provide for verifying the PC end software that error compensation parameter sets, by a serial interface Mouth communicates with PC.

4. according to arbitrary described highly integrated for squirrel cage type hollow-core current transformer of claims 1 to 3 Digital integrator, it is characterised in that this digital integrator uses 32 high-speed CPUs to be module core, at IC Reason device uses ADE7858 computation chip.

Highly integrated digital integration for squirrel cage type hollow-core current transformer the most according to claim 4 Device, it is characterised in that be additionally provided with RS485 communication interface, will be surveyed by described RS485 communication interface The data communication obtained controls to other required higher levels.

6. according to arbitrary described highly integrated for squirrel cage type hollow-core current transformer of claims 1 to 3 Digital integrator, it is characterised in that be additionally provided with RS485 communication interface, is connect by described RS485 communication Measured data communication controls to other required higher levels by mouth.