CN218824482U

CN218824482U - Harmonic wave measuring circuit

Info

Publication number: CN218824482U
Application number: CN202222922587.4U
Authority: CN
Inventors: 袁春兰; 杨平
Original assignee: Sichuan Vocational College of Chemical Technology
Current assignee: Sichuan Vocational College of Chemical Technology
Priority date: 2022-11-03
Filing date: 2022-11-03
Publication date: 2023-04-07
Anticipated expiration: 2032-11-03

Abstract

The utility model discloses a harmonic measurement circuit, belonging to the technical field of harmonic measurement, comprising a receiving circuit for receiving an input circuit or voltage, wherein the receiving circuit is provided with an input amplifier which can amplify the received current or voltage; the measuring circuit is used for measuring input current or voltage and comprises a mutual inductor consisting of a plurality of filters and a detector array; and the multi-path display is electrically connected with the measuring circuit and used for displaying the multi-path circuit in the measuring circuit. In a high-voltage and ultrahigh-voltage conversion circuit in a receiving circuit, za is equivalent impedance of a leakage capacitance reaction between a primary side leakage reactance and an auxiliary leakage reactance, zm is excitation impedance, zs is impedance of an auxiliary side winding to a ground capacitor, zc is auxiliary side leakage reactance, and Zb is composite impedance. The presence of the conversion circuit can form an equivalent circuit inside, and the high-voltage circuit and the ultrahigh-voltage circuit can be converted into a low-voltage circuit for measurement in use.

Description

Harmonic wave measuring circuit

Technical Field

The utility model relates to a harmonic measurement technical field, concretely relates to is a harmonic measurement circuit.

Background

The harmonic measurement of high voltage can not be directly carried out, and the current mainstream is to extract voltage and current signals through a mutual inductor, so that the sensing precision of the mutual inductor to the harmonic becomes an important link influencing the harmonic measurement accuracy compared with the direct measurement of low voltage.

And the low voltage accuracy of the common electromagnetic current transformer is high, but the error is large when the high voltage and the ultrahigh voltage are measured.

Therefore, a circuit capable of accurately measuring the harmonic waves of high voltage and high current is urgently needed.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a harmonic measuring circuit, this harmonic measuring circuit are applicable to the high voltage circuit, have the accurate characteristics of measuring result, can effectively solve the problem of proposing in the above-mentioned background art.

In order to achieve the above purpose, the utility model provides a following technical scheme:

the harmonic measurement circuit comprises a receiving circuit, a harmonic detection circuit and a harmonic detection circuit, wherein the receiving circuit is used for receiving an input circuit or voltage, and an input amplifier capable of amplifying the received current or voltage is arranged in the receiving circuit; one end of the input amplifier is connected with a resonant circuit, the resonant circuit comprises a variable capacitance diode, one end of the variable capacitance diode is connected with the first strip-shaped linear inductor and the second strip-shaped linear inductor in series, and the other end of the variable capacitance diode is connected with the capacitor in parallel to achieve resonance.

The measuring circuit is used for measuring input current or voltage and comprises a mutual inductor consisting of a plurality of filters and a detector array; one end of the measuring circuit is connected with a resonance circuit in the receiving circuit, and harmonic waves are generated through the resonance circuit to measure the generated harmonic waves;

and the multi-path display is electrically connected with the measuring circuit and used for displaying the multi-path circuit in the measuring circuit.

As a further aspect of the present invention: wherein, a high voltage and ultrahigh voltage conversion circuit is connected in the receiving circuit.

As the utility model discloses further scheme again: the filters are band-pass filters, and the band-pass filters are connected in parallel.

As a further aspect of the present invention: the detectors are also connected in parallel, and the detectors and the filter are connected in parallel one by one.

As a further aspect of the present invention: the multi-path display is a liquid crystal display, and the display mode is double-leaf display.

Compared with the prior art, the beneficial effects of the utility model are that:

in the harmonic measuring apparatus in this embodiment, in the high-voltage and ultra-high-voltage conversion circuit existing in the receiving circuit, za is an equivalent impedance of a leakage capacitance reaction between the primary side leakage reactance and the secondary side leakage reactance, zm is an excitation impedance, zs is an impedance of a secondary side winding to a ground capacitance, zc is a secondary side leakage reactance, and Zb is a complex impedance. In the embodiment, an equivalent circuit can be formed inside by the existence of the conversion circuit, so that the high-voltage circuit and the ultrahigh-voltage circuit can be converted into a low-voltage circuit for measurement in use, and the stability of voltage in the circuit is maintained in the measurement process.

Drawings

Fig. 1 is a block diagram of the measuring circuit of the present invention;

fig. 2 is a schematic diagram of a circuit in the middle conversion circuit of the present invention.

Fig. 3 is a schematic diagram of the middle resonant circuit of the present invention.

The corresponding relationship between the reference numbers of the figures and the names of the components in the figures is as follows:

1. a receiving circuit; 2. a measurement circuit; 3. a multi-way display.

Detailed Description

Please refer to fig. 1 to 3: the embodiment provides a harmonic measurement circuit, which is suitable for a high-voltage circuit, and the circuit structure of the harmonic measurement circuit comprises a receiving circuit 1 for receiving an input circuit or voltage, wherein an input amplifier capable of amplifying the received current or voltage is arranged in the receiving circuit 1. One end of the input amplifier is connected with a resonance circuit, the resonance circuit comprises a variable capacitance diode VD1 and one end of the variable capacitance diode VD1 is connected with a first strip-shaped linear inductor L1 and a second strip-shaped linear inductor L2 in series, and the other end of the variable capacitance diode VD1 is connected with a capacitor C1 in parallel to realize resonance. In practical use, the other ends of the serially connected L1 and L2 are grounded, one end of the capacitor C2 is grounded, the other end of the capacitor C2 is connected in parallel with the first strip-shaped linear inductor L1 and the second strip-shaped linear inductor L2, and the grounding increases the safety of the circuit during detection.

The measuring circuit 2 in this embodiment is used for measuring input current or voltage, and the measuring circuit 2 includes a transformer composed of a plurality of filters and a detector array;

the multi-channel display 3 in this embodiment is electrically connected to the measuring circuit 2, and is configured to display the multi-channel circuit in the measuring circuit 2.

In this embodiment, the input signal is amplified by an amplifier and then sent to a set of parallel band pass filters, the neutral line frequency of the filter is f1, f2, the frequency fn is fixed and is an integral multiple of the power frequency, and f1< f2 > < fn (where n is the highest number of harmonics), and then sent to a multi-path display which displays the harmonic components and their amplitudes contained in the measured signal.

The analog filter harmonic measurement method has the advantages of simple structure and low manufacturing cost.

In addition, a high voltage and ultrahigh voltage conversion circuit is connected to the receiving circuit 1.

In the above embodiment, in the high-voltage and ultra-high-voltage conversion circuit existing in the receiving circuit 1, za is equivalent impedance of the leakage capacitance reaction between the primary side leakage reactance and the secondary side leakage reactance, zm is excitation impedance, zs is impedance of the secondary side winding to the ground capacitance, zc is secondary side leakage reactance, and Zb is composite impedance. In the embodiment, an equivalent circuit can be formed inside by the existence of the conversion circuit, so that the high-voltage circuit and the ultrahigh-voltage circuit can be converted into a low-voltage circuit for measurement in use, and the stability of voltage in the circuit is maintained in the measurement process.

In the present embodiment, the primary winding is to bear the high voltage of the system, and the secondary winding is to operate in an open circuit, so the magnetic density of the voltage transformer is much higher than that of the current transformer, and is generally selected to be 1.1T to 1.2T. The voltage transformer approximates a low capacity high voltage transformer operating at no load.

According to the above description, accurate harmonic measurement can be realized in the range of low pressure and high pressure or ultrahigh pressure.

In this embodiment, the filters are band pass filters, and the band pass filters are connected in parallel. Meanwhile, in the present embodiment, multiple measurements can be performed on the received circuit by a plurality of sets of filters and detectors connected in parallel.

The detectors in this embodiment are also connected in parallel, and the detectors and the filters are connected in parallel one by one.

The multi-channel display in this embodiment is a liquid crystal display, and the display mode is a dual-leaf display.

According to the above embodiment, the utility model can be realized well.

Claims

1. A harmonic measurement circuit, comprising: the receiving circuit (1) is used for receiving an input circuit or voltage, and an input amplifier capable of amplifying the received current or voltage is arranged in the receiving circuit (1); one end of the input amplifier is connected with a resonance circuit, the resonance circuit comprises a variable capacitance diode VD1, one end of the variable capacitance diode VD1 is connected with the first strip-shaped linear inductor L1 and the second strip-shaped linear inductor L2 in series, and the other end of the variable capacitance diode VD1 is connected with the capacitor C1 in parallel to realize resonance;

the measuring circuit (2) is used for measuring input current or voltage, and the measuring circuit (2) comprises a transformer consisting of a plurality of filters and a detector array; one end of the measuring circuit (2) is connected with a resonant circuit in the receiving circuit (1), and harmonic waves are generated through the resonant circuit to measure the generated harmonic waves;

and the multi-path display (3) is electrically connected with the measuring circuit (2) and is used for displaying the multi-path circuit in the measuring circuit (2).

2. A harmonic measurement circuit according to claim 1, characterized in that a high-voltage and ultra-high-voltage conversion circuit is connected in the receiving circuit (1).

3. A harmonic measurement circuit according to claim 2, wherein the filters are bandpass filters and the bandpass filters are coupled in parallel.

4. A harmonic measurement circuit as claimed in claim 1, wherein the detectors are also connected in parallel and are connected in series and in parallel to the filter.

5. The harmonic measurement circuit of claim 1, wherein the multi-way display is a liquid crystal display and the display mode is a dual-leaf display.