A drive system for suppressing distributed parameter errors in AC micro-resistance measurement circuits

Abstract

This invention provides a drive system for suppressing distributed parameter errors in AC micro-resistance measurement circuits. Based on the analysis of the characteristics of distributed parameters such as inductance and capacitance in the AC micro-resistance measurement circuit, an AC quadrature compensation technique is adopted. Specifically, the quadrature compensation signal is fed back to the measurement circuit of the resistor Rx under test through electromagnetic induction between the first secondary coil W3 and the primary coil W1 to suppress the influence of distributed parameters in the AC micro-resistance measurement circuit on the phase of the measurement signal, eliminate the quadrature interference signal generated by the distributed parameters, thereby reducing the test error caused by the circuit distributed parameters and improving the measurement accuracy of the equipment. The drive system of this invention can be widely used in precision temperature measuring instruments such as AC platinum resistance thermometers, and can effectively suppress thermoelectric potential errors and system noise interference in the equipment, greatly improving the measurement accuracy of the equipment.

Description

Technical Field

[0001] This invention belongs to the field of precision testing, and in particular relates to a drive system for suppressing distributed parameter errors in AC micro-resistance measurement circuits. Background Technology

[0002] Resistance, as a fundamental physical quantity in electrical measurement, is involved in all aspects of the national economy, scientific research, national defense, and industrial production. It plays a crucial role in scientific research, production, and daily life, and obtaining resistance values ​​quickly and accurately is of great significance. With the advancement of science and technology, the application of many new disciplines and technologies relies heavily on the precise measurement of resistance. For example, in materials science, the electrical properties of many metals change with temperature, and the changes in most of these electrical properties are closely related to changes in resistance. Therefore, the precise measurement of minute resistances can provide strong theoretical support for the study of the properties of such materials. In the field of temperature measurement, standard platinum resistance thermometers are commonly used for precision temperature measurement. Temperature is often acquired by precisely measuring the resistance of these sensors, such as the FLUKE 15XX series from the United States, the GLOK 6622 series from Canada, and other similar sensors. High-end precision thermometers used in the market, such as the MI6010 series and the British ASLF500, all employ the principle of high-precision resistance measurement. In the aerospace and defense industries, during routine maintenance of missile vehicles, it is necessary to measure the resistance of components such as pyrotechnics, relays, and switches in the equipment circuits to understand the quantitative changes in the equipment. For example, the performance and reliability of pyrotechnics play a crucial role in whether the aircraft can operate normally. Pyrotechnic testing is an important part of the aircraft's self-inspection and routine testing. It is necessary to periodically and accurately measure the change curve of the resistance value of the pyrotechnics without power to determine whether the performance of the pyrotechnics is intact.

[0003] In recent years, with the enhancement of my country's comprehensive national strength, the number of precision instruments used in basic science, industrial production, and national defense has also increased. Significant achievements have been made in the field of high-precision resistance measurement. However, facing the demands of new scientific research, resistance measurement remains a particularly challenging topic. Especially when the resistance being measured is small, the contact resistance and wire resistance in the measurement circuit can introduce significant interference errors, severely impacting the accurate measurement of minute resistances. Simultaneously, when the resistance being measured is extremely small, the signal detected in the circuit will be very weak and easily drowned out by circuit noise, greatly affecting measurement accuracy. Furthermore, using a large current to drive the minute resistor in the test circuit can easily damage the resistor, and as the measurement time increases, the measured resistor will experience temperature changes due to the excessive circuit current, leading to a certain degree of loss in measurement accuracy. Therefore, developing a high-precision minute resistance measurement circuit under low-current driving conditions is imperative. It is necessary to propose the development of a high-precision minute resistance tester, and through the development of this standard device, commercialize it to meet the key metrological needs of project construction and research support conditions in various scientific research and production fields in my country.

[0004] However, due to the unavoidable presence of distributed parameters such as inductance and capacitance in the resistance measurement circuit of high-precision thermometers and other equipment, orthogonal interference signals are generated under AC constant current source driving conditions. This will affect the measurement accuracy of the equipment and fail to meet the measurement accuracy requirement of a maximum error of 0.0002Ω within the 0–120Ω range. To improve the measurement accuracy, it is urgent to research a driving circuit that suppresses the distributed parameter errors in the measurement circuit of AC platinum resistance thermometers to meet the measurement needs of high-precision, small resistances. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a drive system for suppressing distributed parameter errors in AC micro-resistance measurement circuits, which can improve resistance measurement accuracy and meet the measurement requirements of AC micro-resistance measuring instruments.

[0006] A driving system for suppressing distributed parameter errors in AC micro-resistance measurement circuits includes a sinusoidal AC constant current source, a quadrature phase shifting circuit, a multiplication circuit, a phase detection circuit, a switch array I, a switch array II, a first coil X, a second coil S, and a standard resistor Rs. The sinusoidal AC constant current source is connected in series with the resistor to be measured Rx and the standard resistor Rs and then grounded. At the same time, the standard resistor Rs is connected to the primary coil of the second coil S through the switch array II, and the resistor to be measured Rx is connected to the primary coil W1 of the first coil X through the switch array I.

[0007] The phase detection circuit is used to measure the phase difference between the first induced signal output by the second secondary coil W2 of the first coil X and the second induced signal output by the secondary coil of the second coil S, and convert the phase difference into a DC voltage signal of the corresponding level.

[0008] The quadrature phase-shifting circuit is used to quadrature-shift the sinusoidal voltage signal of the sinusoidal AC constant current source to obtain a phase-shifted signal;

[0009] The multiplication circuit is used to adjust the amplitude of the phase-shifting signal through a DC voltage signal to obtain a quadrature compensation signal;

[0010] The quadrature compensation signal is connected to the first secondary coil W3 of the first coil X, thereby feeding the quadrature compensation signal back to the measurement circuit of the resistor Rx under test through the electromagnetic induction between the first secondary coil W3 and the primary coil W1, thus suppressing the quadrature component in the measurement circuit.

[0011] Furthermore, switch array I and switch array II are used to control the amplification ratio coefficients of the first coil X and the second coil S, respectively, so that the voltage drop across the resistor Rx to be measured and the standard resistor Rs is the same.

[0012] Furthermore, copper terminals and connecting wires are used to connect the resistor under test Rx and the standard resistor Rs to the drive system.

[0013] Furthermore, the standard resistor Rs is an AC standard resistor.

[0014] Furthermore, the effective value of the sinusoidal AC constant current source is 1mA.

[0015] Beneficial effects:

[0016] 1. This invention provides a drive system for suppressing distributed parameter errors in AC micro-resistance measurement circuits. Based on the analysis of the characteristics of distributed parameters such as inductance and capacitance in the AC micro-resistance measurement circuit, an AC quadrature compensation technique is adopted. That is, the quadrature compensation signal is fed back to the measurement circuit of the resistor Rx under test through the electromagnetic induction between the first secondary coil W3 and the primary coil W1 to suppress the influence of distributed parameters in the AC micro-resistance measurement circuit on the phase of the measurement signal, eliminate the quadrature interference signal generated by the distributed parameters, thereby reducing the test error caused by the circuit distributed parameters and improving the measurement accuracy of the equipment. The drive system of this invention can be widely used in precision temperature measuring instruments such as AC platinum resistance thermometers, and can effectively suppress thermoelectric potential errors and system noise interference in the equipment, greatly improving the measurement accuracy of the equipment.

[0017] 2. This invention provides a drive system for suppressing the distributed parameter error of AC micro-resistance measurement circuit. By using terminals made of low thermoelectric potential materials such as copper and connecting wires made of copper to connect the resistor to be measured Rx and the standard reference resistor Rs to the drive system, the inductance distributed parameter introduced by the terminals and wires can be reduced.

[0018] 3. This invention provides a drive system for suppressing the distributed parameter error of AC micro-resistance measurement circuit. The standard resistor Rs is a high-precision AC standard resistor, which can reduce the inductance distributed parameter introduced by the standard resistor.

[0019] 4. This invention provides a drive system for suppressing distributed parameter errors in AC micro-resistance measurement circuits. Under the condition of a 1mA AC constant current source drive circuit, it can accurately measure small resistance values ​​within the range of 0 to 120Ω, and thus can be widely used in precision temperature measuring instruments such as AC platinum resistance thermometers. Attached Figure Description

[0020] Figure 1 The present invention provides a principle block diagram of a drive system for suppressing distributed parameter errors in an AC micro-resistance measurement circuit. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0022] The working principle of the AC micro-resistance measurement circuit is mainly based on using an AC constant current source as the driving circuit to acquire the resistance value of a micro-resistance device and compare it with a standard resistor to calculate the resistance value of the device under test. Specifically, the resistance value of the device under test can be calculated using the resistance value of the standard resistor and the amplification ratio of the two coils. To address the phenomenon of distributed parameters such as inductance and capacitance in the AC micro-resistance measurement circuit, this invention proposes a driving system to suppress the distributed parameter errors in the AC micro-resistance measurement circuit, thereby suppressing the test errors caused by the distributed parameters of the measurement circuit.

[0023] like Figure 1As shown, a driving system for suppressing distributed parameter errors in an AC micro-resistance measurement circuit includes a sinusoidal AC constant current source with an effective value of 1mA, a quadrature phase-shifting circuit, a multiplication circuit, a phase-detection circuit, switch array I, switch array II, a first coil X, a second coil S, and a standard resistor Rs. The sinusoidal AC constant current source is connected in series with the resistor to be measured Rx and the standard resistor Rs and then grounded. Simultaneously, the standard resistor Rs is connected to the primary coil of the second coil S through switch array II, and the resistor to be measured Rx is connected to the primary coil W1 of the first coil X through switch array I. Switch array I and switch array II are used to control the amplification ratio coefficients of the first coil X and the second coil S, respectively, so that the voltage drop across the resistor to be measured Rx and the standard resistor Rs is the same.

[0024] The phase detection circuit is used to measure the phase difference between the first induced signal output by the second secondary coil W2 of the first coil X and the second induced signal output by the secondary coil of the second coil S, and convert the phase difference into a DC voltage signal of the corresponding level.

[0025] The quadrature phase-shifting circuit is used to quadrature the phase of the sinusoidal voltage signal of the sinusoidal AC constant current source, that is, to shift the phase by 90° to obtain the phase-shifted signal; wherein, the phase-shifted signal serves as the reference signal source for the quadrature compensation signal;

[0026] The multiplication circuit is used to adjust the amplitude of the phase-shifting signal through a DC voltage signal to obtain a quadrature compensation signal;

[0027] The quadrature compensation signal is connected to the first secondary coil W3 of the first coil X, thereby feeding the quadrature compensation signal back to the measurement circuit of the resistor Rx under test through the electromagnetic induction between the first secondary coil W3 and the primary coil W1, thereby suppressing the quadrature component in the measurement circuit and suppressing the measurement error introduced by the distributed parameters in the measurement circuit.

[0028] It should be noted that the sinusoidal AC constant current source with an effective value of 1mA has high stability in phase and amplitude; the standard resistor Rs is a high-precision AC standard resistor, which can reduce the inductance distribution parameters introduced by the standard resistor; the first coil X and the second coil S are proportionally adjustable magnetic induction coils. By selecting different switches on the switch array to conduct, the amplification ratio coefficients of the magnetic induction coils corresponding to the resistor under test Rx and the standard resistor Rs are adjusted, so that the voltage drop across Rx and Rs is adjusted to be consistent, improving the consistency of the test state; according to Figure 1 The connection relationship is established by using terminals made of low thermoelectric potential materials such as copper and copper connecting wires to connect the resistor to be measured Rx and the standard resistor Rs into the driving circuit. The resistor to be measured Rx can be a platinum resistance thermometer. The corresponding switch array can be initialized according to the sampling voltage of the resistor to be measured Rx and the standard resistor Rs to control the amplification ratio coefficient of the magnetic induction coil.

[0029] In summary, by employing the driving system of this invention, and through orthogonal compensation technology—that is, by feeding back the orthogonal compensation signal to the measurement circuit of the resistor under test Rx through electromagnetic induction between the first secondary coil W3 and the primary coil W1—the phase change caused by distributed parameters in the AC micro-resistance measurement circuit can be effectively suppressed, the orthogonal interference signal generated by distributed parameters can be eliminated, and the test error caused by the distributed parameters of the measurement circuit can be reduced. This enables the AC micro-resistance measurement circuit to accurately measure inductive and capacitive loads, effectively improving the measurement accuracy and load characteristics of the AC micro-resistance measurement circuit.

[0030] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A drive system for suppressing distributed parameter errors in AC micro-resistance measurement circuits, characterized in that, It includes a sinusoidal AC constant current source, a quadrature phase shifting circuit, a multiplication circuit, a phase detection circuit, a switch array I, a switch array II, a first coil X, a second coil S, and a standard resistor Rs. The sinusoidal AC constant current source is connected in series with the resistor to be measured Rx and the standard resistor Rs and then grounded. At the same time, the standard resistor Rs is connected to the primary coil of the second coil S through the switch array II, and the resistor to be measured Rx is connected to the primary coil W1 of the first coil X through the switch array I. The phase detection circuit is used to measure the phase difference between the first induced signal output by the second secondary coil W2 of the first coil X and the second induced signal output by the secondary coil of the second coil S, and convert the phase difference into a DC voltage signal of the corresponding level. The quadrature phase-shifting circuit is used to quadrature-shift the sinusoidal voltage signal of the sinusoidal AC constant current source to obtain a phase-shifted signal; The multiplication circuit is used to adjust the amplitude of the phase-shifting signal through a DC voltage signal to obtain a quadrature compensation signal; The quadrature compensation signal is connected to the first secondary coil W3 of the first coil X, thereby feeding the quadrature compensation signal back to the measurement circuit of the resistor Rx under test through the electromagnetic induction between the first secondary coil W3 and the primary coil W1, thereby suppressing the quadrature component in the measurement circuit.

2. The driving system for suppressing distributed parameter errors in AC micro-resistance measurement circuits as described in claim 1, characterized in that, Switch array I and switch array II are used to control the amplification ratio coefficients of the first coil X and the second coil S, respectively, so that the voltage drop across the resistor Rx to be measured and the standard resistor Rs is the same.

3. The driving system for suppressing distributed parameter errors in AC micro-resistance measurement circuits as described in claim 1, characterized in that, The resistor to be tested, Rx, and the standard resistor, Rs, are connected to the drive system using copper terminals and connecting wires.

4. A drive system for suppressing distributed parameter errors in an AC micro-resistance measurement circuit as described in any one of claims 1 to 3, characterized in that, The standard resistor Rs is an AC standard resistor.

5. A drive system for suppressing distributed parameter errors in AC micro-resistance measurement circuits as described in any one of claims 1 to 3, characterized in that, The effective value of the sinusoidal AC constant current source is 1mA.

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