An impedance measurement method

Abstract

The present invention relates to the technical field of instruments and meters, and specifically provides an impedance measurement method, aiming to solve the technical problem of relatively large measurement errors corresponding to the existing impedance measurement methods. For this purpose, the impedance measurement method of the present invention includes: obtaining an input impedance measurement value of an impedance network based on an impedance measurement component; obtaining an input voltage and an output voltage of the impedance network based on a voltage measurement component; and determining a transfer impedance of the impedance network based on the input impedance measurement value of the impedance network, the input voltage, and the output voltage of the impedance network. In this way, the measurement accuracy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of instruments and meters, and specifically provides an impedance measurement method. Background Art

[0002] Currently, the existing measurement method for an impedance network is to apply a sine signal across the impedance network, then use a voltmeter to measure the input voltage and output voltage respectively, and use an ammeter to measure the input current, so as to determine the input impedance as Zin = Uin / I and the transfer impedance as Zout = Uout / I, and finally compare the obtained values with the ideal values. However, in this measurement method, there is no high-precision ammeter that can measure the current between 100 kHz and 1 MHz. Therefore, the measurement error of this method is relatively large, and there is also a problem that the current traceability between 100 kHz and 1 MHz cannot be solved.

[0003] Correspondingly, there is a need in the art for a new impedance measurement solution to solve the above problems. Summary of the Invention

[0004] In order to overcome the above defects, the present invention is proposed to provide a technical solution to solve or at least partially solve the technical problem of relatively large measurement error corresponding to the existing impedance measurement method. The present invention provides an impedance measurement method.

[0005] In a first aspect, the present invention provides an impedance measurement method, which is applied to an impedance network and includes: obtaining an input impedance measurement value of the impedance network based on an impedance measurement component; obtaining the input voltage and output voltage of the impedance network based on a voltage measurement component; and determining the transfer impedance of the impedance network based on the input impedance measurement value of the impedance network, the input voltage of the impedance network, and the output voltage. The impedance measurement method provided by the present invention first obtains the input impedance measurement value of the impedance network by using the impedance measurement component, then obtains the input voltage and output voltage of the impedance network based on the voltage measurement component, and finally determines the transfer impedance of the impedance network based on the input impedance measurement value of the impedance network, the input voltage of the impedance network, and the output voltage, thereby reducing the impedance measurement error, improving the measurement efficiency and measurement accuracy, and at the same time solving the current traceability problem at frequencies between 100 kHz and 1 MHz.

[0006] In one embodiment, obtaining the input impedance measurement value of the impedance network based on the impedance measurement component includes: connecting the impedance measurement component and the impedance network; adjusting the impedance measurement component to a first frequency; and measuring the input impedance measurement value of the impedance network corresponding to the first frequency by using the impedance measurement component. Measuring the input impedance measurement value of the impedance network at the corresponding frequency through the impedance measurement component provides a basic support for subsequent determination of the input impedance of the impedance network.

[0007] In one embodiment, obtaining the input voltage and output voltage of the impedance network based on the voltage measurement component includes: connecting a signal generator, the impedance network, and the voltage measurement component; adjusting the signal generator to a second frequency; using the voltage measurement component to measure the output voltage of the signal generator and the output voltage of the impedance network corresponding to the second frequency; and determining the input voltage of the impedance network based on the output voltage of the signal generator. By measuring the output voltage of the signal generator and the output voltage of the impedance network at the corresponding frequency with the voltage measurement component, the input voltage of the impedance network can be further determined based on the output voltage of the signal generator. Based on this input voltage, the input current can be further calculated. The method is novel and avoids the technical problem of large measurement errors caused by the lack of a high-precision ammeter to measure current in the prior art when the frequency is between 100 kHz and 1 MHz.

[0008] In one embodiment, determining the input voltage of the impedance network based on the output voltage of the signal generator includes: using the output voltage of the signal generator as the input voltage of the impedance network. Directly using the output voltage of the signal generator as the input voltage of the impedance network is simple and easy to implement, further improving the measurement efficiency.

[0009] In one embodiment, the second frequency is equal to the first frequency of the impedance measurement component, and the second frequency is in the range of 20 Hz to 1 MHz. By setting the second frequency equal to the first frequency of the impedance measurement component, the transfer impedance of the impedance network can be calculated based on the input impedance measurement value obtained at the first frequency, the input voltage, and the output voltage obtained at the second frequency, which is beneficial to improving the accuracy of impedance calculation.

[0010] In one embodiment, determining the transfer impedance of the impedance network based on the input impedance measurement value of the impedance network, the input voltage, and the output voltage of the impedance network includes: determining the input impedance of the impedance network based on the input impedance measurement value of the impedance network; and determining the transfer impedance of the impedance network based on the input impedance, input voltage, and output voltage. In one embodiment, determining the input impedance of the impedance network based on the input impedance measurement value of the impedance network includes: using the input impedance measurement value of the impedance network as the input impedance of the impedance network. In one embodiment, determining the transfer impedance of the impedance network based on the input impedance, input voltage, and output voltage includes: determining the input current of the impedance network based on the input impedance and input voltage, and the input current calculation formula is:

[0011] I = U in / Z0

[0012] In the above formula, I is the input current, U inV is the input voltage and Z0 is the input impedance;

[0013] Determine the transfer impedance of the impedance network based on the input current and output voltage of the impedance network. The calculation formula for the transfer impedance is:

[0014] Z out = U out / I

[0015] In the above formula, Z out is the transfer impedance, U out is the output voltage, and I is the input current. By determining the input impedance of the impedance network based on the measured value of the input impedance of the impedance network, and determining the transfer impedance according to the input impedance, input voltage, and output voltage, the accurate calculation of the impedance is achieved, the calculation accuracy is improved, the calculation error is reduced, and at the same time, the problem of current traceability with frequencies in the range of 100 kHz to 1 MHz is solved.

[0016] In one embodiment, the impedance measurement component is any one of an impedance analyzer and an LCR tester. Selecting an impedance analyzer or an LCR tester as the impedance measurement component can obtain a relatively accurate measured value of the input impedance, providing a basic support for the subsequent impedance calculation of the impedance network.

[0017] In one embodiment, the voltage measurement component is a digital multimeter. The digital multimeter used in this application is a high-precision digital multimeter, which can record test data for a long time and has a high measurement accuracy, further reducing the measurement error. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Referring to the accompanying drawings, the disclosure of the present invention will become more readily understood. It is easily understood by those skilled in the art that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In addition, similar numbers in the figures are used to represent similar components, where:

[0019] Figure 1 is a schematic flowchart of the main steps of an impedance measurement method according to an embodiment of the present invention;

[0020] Figure 2 is a schematic circuit connection diagram of impedance measurement according to an embodiment of the present invention;

[0021] Figure 3 is a schematic circuit connection diagram of voltage measurement according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] Some embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principle of the present invention and are not intended to limit the scope of protection of the present invention.

[0023] In the description of the present invention, "module" and "processor" may include hardware, software, or a combination of both. A module may include a hardware circuit, various suitable sensors, communication ports, memory, and may also include a software part, such as program code, or a combination of software and hardware. A processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor, or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, in hardware, or in a combination of both. A non-transitory computer-readable storage medium includes any suitable medium for storing program code, such as a magnetic disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, and so on. The term "A and / or B" represents all possible combinations of A and B, such as only A, only B, or A and B. The term "at least one of A or B" or "at least one of A and B" has a meaning similar to "A and / or B", and may include only A, only B, or A and B. The singular terms "a" and "the" may also include the plural form.

[0024] Currently, the traditional method for measuring an impedance network is to apply a sine signal across the impedance network, and then use a voltmeter to measure the input voltage and the output voltage respectively, and an ammeter to measure the input current, so as to determine the input impedance as Zin = Uin / I and the transfer impedance as Zout = Uout / I, and finally compare the obtained values with the ideal values. However, in this measurement method, there is no high-precision ammeter that can measure the current between 100 kHz and 1 MHz, so the measurement error of this method is relatively large, and there is also a problem that the current traceability between 100 kHz and 1 MHz cannot be solved. For this reason, the present application proposes an impedance measurement method. First, an input impedance measurement value of the impedance network is obtained by using an impedance measurement component, then the input voltage and the output voltage of the impedance network are obtained based on a voltage measurement component, and finally the transfer impedance of the impedance network is determined based on the input impedance measurement value of the impedance network, the input voltage, and the output voltage of the impedance network, thereby reducing the impedance measurement error, improving the measurement efficiency and measurement accuracy, and at the same time solving the problem of current traceability at frequencies between 100 kHz and 1 MHz.

[0025] Refer to the attached Figure 1 , Figure 1 is a schematic diagram of the main step flow of an impedance measurement method according to an embodiment of the present invention. As Figure 1 shown, the impedance measurement method in the embodiment of the present invention mainly includes the following steps S101 - step S103.

[0026] Step S101: Obtain the input impedance measurement value of the impedance network based on the impedance measurement component. Specifically, in the process of obtaining the input impedance measurement value of the impedance network based on the impedance measurement component, the impedance measurement component and the impedance network can be connected in sequence first, then the impedance measurement component is adjusted to the first frequency, and finally the input impedance measurement value of the impedance network corresponding to the first frequency is measured by the impedance measurement component. Measuring the input impedance measurement value of the impedance network at the corresponding frequency through the impedance measurement component provides a basic support for determining the input impedance of the impedance network in the subsequent steps.

[0027] The impedance measurement component in this application can be any one of an impedance analyzer and an LCR tester, but is not limited thereto. It can also be other impedance measurement components capable of measuring the measurement value of the impedance network. Among them, the impedance analyzer can be the impedance analyzer E4490A (KEYSIGHT), and the LCR tester can be the LCR meter E4980A (KEYSIGHT). Selecting an impedance analyzer or an LCR tester as the impedance measurement component can obtain a relatively accurate input impedance measurement value, providing a basic support for the subsequent calculation of the transfer impedance of the impedance network.

[0028] The first frequency in this step is the measurement frequency of the impedance analyzer or the LCR tester, and its value range is from 20 Hz to 1 MHz. By changing the measurement frequency of the impedance analyzer or the LCR tester, the input impedance measurement values of the impedance network at different frequencies can be measured.

[0029] Step S102: Obtain the input voltage and output voltage of the impedance network based on the voltage measurement component. In the process of obtaining the input voltage and output voltage of the impedance network based on the voltage measurement component, first, connect the signal generator, the impedance network, and the voltage measurement component. Then, adjust the signal generator to the second frequency. Next, use the voltage measurement component to measure the output voltage of the signal generator and the output voltage of the impedance network corresponding to the second frequency. Specifically, take the output voltage of the signal generator as the input voltage of the impedance network. Through the voltage measurement component, measure the output voltage of the signal generator and the output voltage of the impedance network at the corresponding frequency. At the same time, the input voltage of the impedance network can be further determined based on the output voltage of the signal generator. Based on this input voltage, the input current can be further calculated. The method is novel and avoids the technical problem of large measurement errors caused by the lack of a high-precision ammeter to measure current when the frequency is between 100 kHz and 1 MHz in the prior art. At the same time, directly taking the output voltage of the signal generator as the input voltage of the impedance network is simple and easy to implement, further improving the measurement efficiency. The second frequency of the signal generator set in this application is equal to the first frequency of the aforementioned impedance measurement component. Specifically, in actual measurement, when using the voltage measurement component to obtain the input voltage and output voltage of the impedance network, the value of the adjusted second frequency should be equal to the value of the first frequency adjusted when using the aforementioned impedance measurement component to obtain the input impedance measurement value. By setting the second frequency equal to the first frequency of the impedance measurement component, the transfer impedance of the impedance network can be calculated based on the input impedance measurement value obtained at the first frequency, the input voltage, and the output voltage obtained at the second frequency, which is beneficial to improving the accuracy of impedance calculation.

[0030] The voltage measurement component in this application is a digital multimeter, specifically, it can be a high-precision digital multimeter, such as the high-precision digital multimeter 8508A (FLUKE) or 3458A (KEYSIGHT). The digital multimeter adopted in this application is a high-precision digital multimeter, which can record test data for a long time and has high measurement accuracy, further reducing the measurement error.

[0031] Step S103: Determine the transfer impedance of the impedance network based on the measured input impedance of the impedance network, the input voltage, and the output voltage of the impedance network. Specifically, in the process of determining the transfer impedance of the impedance network based on the measured input impedance of the impedance network, the input voltage, and the output voltage of the impedance network, the input impedance of the impedance network can be first determined based on the measured input impedance of the impedance network. Specifically, the measured input impedance value of the impedance network is used as the input impedance of the impedance network. Then, the transfer impedance of the impedance network is determined based on the input impedance, the input voltage, and the output voltage. Specifically, in the process of determining the transfer impedance of the impedance network based on the input impedance, the input voltage, and the output voltage, the input current of the impedance network is first determined based on the input impedance and the input voltage, and then the transfer impedance of the impedance network is determined based on the input current and the output voltage of the impedance network. The calculation formulas for the input current and the transfer impedance at the output end are respectively:

[0032] I = U in / Z0

[0033] Z out = U out / I

[0034] In the above formula, I is the input current, U in is the input voltage, Z0 is the input impedance, and Z out is the transfer impedance, and U out is the output voltage. By determining the input impedance of the impedance network through the measured input impedance value of the impedance network and determining the transfer impedance of the impedance network according to the input impedance, the input voltage, and the output voltage, the accurate calculation of the transfer impedance is realized, the calculation accuracy is improved, the calculation error is reduced, and at the same time, the problem of current traceability with frequencies in the range of 100 kHz to 1 MHz is solved.

[0035] Based on the above steps S101 - S103, first, the measured input impedance value of the impedance network is obtained by using the impedance measurement component, then the input voltage and the output voltage of the impedance network are obtained based on the voltage measurement component, and finally, the transfer impedance of the impedance network is determined based on the measured input impedance value of the impedance network, the input voltage, and the output voltage of the impedance network, thereby reducing the impedance measurement error, improving the measurement efficiency and measurement accuracy, and at the same time solving the problem of current traceability with frequencies in the range of 100 kHz to 1 MHz.

[0036] In one embodiment, the connection relationship between the impedance measurement component and the impedance network is as Figure 2 shown. The output end of the impedance analyzer or LCR meter is connected to the input end of the impedance network, and impedance measurement settings are made for the impedance analyzer or LCR meter. Among them, the measurement frequency can be set to 20 Hz. In this embodiment, the measured input impedance value read by the impedance analyzer or LCR meter is Z0, and this value is the input impedance of the impedance network.

[0037] The connection relationships among the signal generator, the impedance network, and the voltage measurement component are specifically as follows Figure 3 described. The output terminal of the signal generator is connected to the input terminal of the impedance network, and the output terminal of the impedance network is connected to the AC voltage measurement terminal of the digital multimeter. Set the amplitude of the signal generator to 1 Vrms. Here, 1 Vrms is just an example output voltage value, and the output voltage value can be changed according to actual measurement requirements. Set the frequency to 20 Hz. Use the digital multimeter to measure the output voltage of the signal generator. In this embodiment, the measured output voltage of the signal generator is 1 V. This output voltage is the input voltage of the impedance network, and use the digital multimeter to measure the output voltage Uout of the impedance network.

[0038] After determining the input impedance of the impedance network, the input voltage of the impedance network, and the output voltage through the foregoing steps, the transfer impedance of the impedance network can also be calculated. Specifically, since the input voltage U in is 1 V and the input impedance is the measured input impedance value Z0 of the input impedance, the input current can be calculated according to the following formula:

[0039] I = U in / Z0 = 1 / Z0

[0040] The transfer impedance can be obtained according to the formula Z out = U out / I = U out *Z0. Through the impedance measurement method in this application, the accuracy of the measurement result is improved, the measurement error is reduced, and the current traceability problem in the range of 100 kHz to 1 MHz is solved, and the measurement accuracy is improved.

[0041] It should be noted that although the above embodiments describe the various steps in a specific order, those skilled in the art can understand that in order to achieve the effects of the present invention, it is not necessary for different steps to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders, and these changes are all within the protection scope of the present invention.

[0042] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. An impedance measurement method, applied to an impedance network, characterized in that, Including: Connect the impedance measurement component and the impedance network; Adjust the impedance measurement component to the first frequency; Obtain the input impedance measurement value of the impedance network based on the impedance measurement component; Connect the signal generator, the impedance network and the voltage measurement component; Adjust the signal generator to the second frequency, where the second frequency is equal to the first frequency of the impedance measurement component; Obtain the input voltage and output voltage of the impedance network based on the voltage measurement component; Determine the transfer impedance of the impedance network based on the input impedance measurement value of the impedance network, the input voltage and output voltage of the impedance network, including: Determine the input impedance of the impedance network based on the input impedance measurement value of the impedance network; Determine the transfer impedance of the impedance network based on the input impedance, input voltage and output voltage, including: determine the input current of the impedance network based on the input impedance and input voltage; determine the transfer impedance of the impedance network based on the input current and output voltage of the impedance network.

2. The impedance measurement method according to claim 1, characterized in that, Obtaining the input impedance measurement value of the impedance network based on the impedance measurement component includes: Measure the input impedance measurement value of the impedance network corresponding to the first frequency using the impedance measurement component.

3. The impedance measurement method according to claim 1, characterized in that, Obtaining the input voltage and output voltage of the impedance network based on the voltage measurement component includes: Measure the output voltage of the signal generator corresponding to the second frequency and the output voltage of the impedance network using the voltage measurement component; Determine the input voltage of the impedance network based on the output voltage of the signal generator.

4. The impedance measurement method according to claim 3, characterized in that, Determining the input voltage of the impedance network based on the output voltage of the signal generator includes: taking the output voltage of the signal generator as the input voltage of the impedance network.

5. The impedance measurement method according to claim 3, characterized in that, The second frequency is in the range of 20 Hz to 1 MHz.

6. The impedance measurement method according to claim 1, characterized in that, Determining the input impedance of the impedance network based on the input impedance measurement value of the impedance network includes: taking the input impedance measurement value of the impedance network as the input impedance of the impedance network.

7. The impedance measurement method according to claim 1, characterized in that, The calculation formula for determining the input current of the impedance network based on the input impedance and input voltage is: I = U in / Z0 In the above formula, I is the input current, U in is the input voltage, and Z0 is the input impedance; The calculation formula for determining the transfer impedance of the impedance network based on the input current and output voltage of the impedance network is: Z out = U out / I In the above formula, Z out is the transfer impedance, U out is the output voltage, and I is the input current.

8. The impedance measurement method according to claim 1, characterized in that, The impedance measurement component is any one of an impedance analyzer and an LCR tester.

9. The impedance measurement method according to claim 1, characterized in that, The voltage measurement component is a digital multimeter.

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