CN111458560A

CN111458560A - High-precision voltmeter based on multielement thin-film thermoelectric converter

Info

Publication number: CN111458560A
Application number: CN202010330099.7A
Authority: CN
Inventors: 韩建强; 沈烽; 朱永胜
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2020-07-28

Abstract

The invention discloses a system composition and a working mechanism of a high-precision voltmeter based on a multi-element thin-film thermoelectric converter, and belongs to the field of micro-electronic mechanical systems. The structure is characterized in that the high-precision voltmeter is composed of a multi-element thin film thermoelectric converter (1), filter circuits (1), (2) and (2), (3), linearizers (1), (4) and (2), (5), a differential amplifying circuit (6), a PI correcting circuit (7) and a direct current voltmeter (8). The multi-element thin film thermoelectric converter (1) is composed of heating resistors 1(9), 2(10) and thermopiles 1(11), 2(12) which are made of the same materials and have the same structure. When an alternating current signal is input to the heating resistors 1 and 9, a temperature difference electromotive force is formed, the feedback voltage loaded on the heating resistors 2 and 10 is changed through a closed loop feedback circuit until the output signal of the differential amplification circuit (6) is 0, and the feedback signal measured by the direct current voltmeter is the effective value of the input alternating current signal. The high-precision voltmeter measures alternating current signals by adopting a thermoelectric conversion method, is suitable for measuring alternating current voltage signals with various waveforms, and has high accuracy and working frequency range.

Description

High-precision voltmeter based on multielement thin-film thermoelectric converter

Technical Field

The invention relates to a voltmeter, in particular to a system composition and a working mechanism of a high-precision voltmeter based on a multi-element thin-film thermoelectric converter, and belongs to the field of micro-electro-mechanical systems (MEMS).

Background

Voltage is the most basic and important parameter in circuits and systems, and voltage measurement plays an important role in electronic measurement. Voltmeter and multimeter including voltage measurement functionality are electronic measurement instruments that are commonly used from primary technicians to advanced technologists. In the event of a fault in an electronic circuit or system, the location and cause of the fault is often determined by detection of a voltage signal in the circuit. In the departments of automatic test systems, production lines, equipment maintenance and the like, the voltmeter is an indispensable instrument. In the sensing field, the vast majority of non-electrical quantities are also measured by conversion to a voltage signal. The main performance parameters of various electronic instruments and devices such as signal generators, transmitters, receivers, etc. are determined by measuring voltages. In electronic metering, parameters such as field strength, attenuation, pulse, amplitude modulation coefficient, waveform nonlinear distortion coefficient and the like are derived quantities of voltage and current.

The effective value of the alternating voltage can reflect the energy of the measured signal, the rated voltage on the nameplate of the alternating current electric appliance is the effective value, and the voltage value indicated by the alternating current voltmeter is also the effective value. In the field of electronic measurement, a general pointer type or digital type voltmeter can be used for accurately measuring voltage signals below 1 kHz. If a high frequency voltage signal is measured, a large error is introduced due to the limitation of the high frequency characteristics of the meter. The working frequency range of magnetoelectric series, electric series, static series, average detection voltmeter and true effective value measuring chips in the market at present is narrow, and although the measuring frequency range of the peak detection electronic voltmeter is wide, the measuring precision is poor, and the effective value of a weak alternating voltage signal cannot be measured.

With the development of science and technology and the continuous progress of society, the requirements on the measurement accuracy, frequency band and measuring range of the instrument are higher and higher, so that the design and the manufacture of the high-accuracy broadband alternating-current voltmeter are problems to be solved urgently.

Disclosure of Invention

The invention aims to provide a high-precision voltmeter based on a multielement thin-film thermoelectric converter, which can accurately measure the effective value of a broadband alternating voltage signal.

In order to achieve the purpose, the basic structure of the high-precision voltmeter based on the multielement thin-film thermoelectric converter is as follows; the high-precision voltmeter based on the multi-element thin-film thermoelectric converter consists of the multi-element thin-film thermoelectric converter, filter circuits 1 and 2, linearization circuits 1 and 2, a differential amplification circuit, a PI correction circuit and a direct-current voltmeter. The multi-element thin-film thermoelectric converter consists of heating resistors 1 and 2 and thermopiles 1 and 2 which are made of the same materials and have the same structure. The hot ends of the thermopiles 1, 2 are respectively close to the heating resistors 1, 2. The thermopile 1 measures the temperature of the heating resistor 1, and the output thermoelectromotive force signal is not influenced by the temperature of the heating resistor 2; the thermopile 2 measures the temperature of the heating resistor 2, and the output thermoelectromotive force signal thereof is not affected by the temperature of the heating resistor 1.

The invention relates to a detection mechanism of a high-precision voltmeter based on a multielement thin-film thermoelectric converter; when an alternating voltage signal is input, the alternating voltage signal is applied to the heating resistor 1, and after the temperature of the heating resistor 1 rises, the heat of the heating resistor 1 causes the thermopile 1 to output the thermoelectromotive force through ways of convection, radiation or heat conduction and the like. The filter circuit 1 filters power frequency and high frequency signals in the thermoelectromotive force, and the linearizing circuit 1 linearizes the thermoelectromotive force signals output by the thermopile 1. The temperature difference electromotive force signals output by the thermopile 2 are changed by feeding back the temperature difference electromotive force signals to the heating resistor 2 through a differential amplification circuit and a PI correction circuit. The difference of the voltage is recalculated by the differential amplifying circuit and fed back to the heating resistor 2 through the PI correction circuit until the output signal of the differential amplifying circuit is 0, and at the moment, the output voltage of the PI correction circuit is the effective value of the input alternating voltage signal, and the voltage is measured by a direct current voltmeter.

The high-precision voltmeter based on the multielement thin-film thermoelectric converter has the advantages that: besides the effective value of the sinusoidal voltage, the method is also suitable for measuring the effective values of distorted sinusoidal waves and non-sinusoidal voltages, such as noise, pulse waves, triangular waves and sawtooth waves, and has high accuracy.

Drawings

Fig. 1 is a schematic structural diagram of a high-precision voltmeter based on a multi-element thin-film thermoelectric converter according to the present invention.

In the drawings:

1-multielement thin film thermoelectric converter 2-filter circuit 13-filter circuit 2

4-linearizer 15-linearizer 26-differential amplifier circuit

7-PI correction circuit 8-DC voltmeter 9-heating resistor 1

10-heating resistor 211-thermopile 112-thermopile 2

Detailed Description

The invention will now be further illustrated, but not limited, by reference to fig. 1 and the examples.

Example (b):

the technical scheme of the invention is utilized to manufacture a high-precision voltmeter based on a multielement thin-film thermoelectric converter.

As shown in the attached figure 1, the high-precision voltmeter consists of a multi-element thin-film thermoelectric converter (1), filter circuits 1(2), 2(3), linearizers 1(4), 2(5), a differential amplifying circuit (6), a PI correcting circuit (7) and a direct-current voltmeter (8). The multi-element thin film thermoelectric converter (1) is composed of heating resistors 1(9), 2(10) and thermopiles 1(11), 2(12) which are made of the same materials and have the same structure.

When no signal is input into the AC voltmeter, the thermoelectromotive forces output by the thermopiles 1(11), 2(12) are the same, and the output signal of the differential amplifying circuit is 0. Therefore, the output signal of the PI correction circuit (7) is also 0.

When an alternating voltage signal is input, the alternating voltage signal is applied to the heating resistors 1 and 9, the filter circuit 1 and 2 filters a power frequency signal and a high frequency signal in an output signal of the thermopile 1 and 11, a temperature difference electromotive force signal output by the thermopile 1 and 11 is linearized through the linearizing circuit 1 and 4, and is fed back to the

heating resistors

2 and 10 through the differential amplifying circuit (6) and the PI correction circuit (7), and the temperature difference electromotive force signal output by the

heating resistors

2 and 10 is changed; the difference of the voltage is recalculated by the differential amplifying circuit (6), and the voltage difference is fed back to the

heating resistors

2 and 10 through the PI correction circuit (7) until the output signal of the differential amplifying circuit (6) is 0, and the output voltage of the PI correction circuit (7) measured by the direct current voltmeter (8) is the effective value of the input alternating current voltage signal.

It is to be understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make modifications, alterations, additions or substitutions within the spirit and scope of the present invention.

Claims

1. A high-precision voltmeter based on many first thin film thermoelectric converter, characterized in that: the high-precision voltmeter consists of a multi-element thin-film thermoelectric converter (1), filter circuits 1(2), 2(3), linearizers 1(4), 2(5), a differential amplifying circuit (6), a PI correcting circuit (7) and a direct-current voltmeter (8); the multi-element thin film thermoelectric converter (1) is composed of heating resistors 1(9), 2(10) and thermopiles 1(11), 2(12) which are made of the same materials and have the same structure.

2. The multielement thin film thermoelectric converter based high precision voltmeter of claim 1, wherein: the multi-element thin film thermoelectric converter (1) is provided with the same heating resistors (1), (9) and (2), (10) and thermopiles (1), (11) and (2), (12); the thermopile 1(11) measures the temperature of the heating resistor 1(9), and the output thermoelectromotive force signal is not influenced by the temperature of the heating resistor 2 (10); the thermopile 2(12) measures the temperature of the heating resistor 2(10), and the output thermoelectromotive force signal is not influenced by the temperature of the heating resistor 1 (9).

3. The multielement thin film thermoelectric converter based high precision voltmeter of claim 1, wherein: the alternating voltage signal is input to a heating resistor 1(9) of a multi-element thin film thermoelectric converter (1), a filter circuit 1(2) filters a power frequency signal and a high frequency signal in an output signal, a temperature difference electromotive force signal output by a thermopile 1(11) is linearized through a linearizing circuit 1(4), and the linearized temperature difference electromotive force signal is fed back to the heating resistor 2(10) through a differential amplifying circuit (6) and a PI correction circuit (7), so that the temperature difference electromotive force signal output by the thermopile 2(12) is changed; the difference of the voltage is recalculated by the differential amplifying circuit (6) and fed back to the heating resistors 2 and 10 through the PI correction circuit (7) until the output signal of the differential amplifying circuit (6) is 0, at the moment, the output voltage of the PI correction circuit (7) is the effective value of the input alternating voltage signal, and the voltage is measured by the direct current voltmeter (8).