CN220399542U

CN220399542U - Non-contact on-line impedance measuring instrument

Info

Publication number: CN220399542U
Application number: CN202322079636.7U
Authority: CN
Inventors: 赵震宇; 谢国祥; 冼国基; 范飞
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-08-03
Filing date: 2023-08-03
Publication date: 2024-01-26
Anticipated expiration: 2033-08-03

Abstract

A non-contact on-line impedance measuring instrument relates to the field of electric or electronic measurement. The device comprises a clamp type inductive coupling probe, a data acquisition module, a signal generation module and a data processing module; the receiving probe and the injection probe are respectively clamped at two ends of a wire of the tested device, and the injection probe is used for injecting sine wave excitation signals generated by the signal generating module; the receiving probe is used for receiving an excitation response signal injected into the tested equipment; the data acquisition module is used for receiving an excitation response signal and a sine wave excitation signal of the tested equipment; the signal generation module is used for sending sine wave excitation signals to the data acquisition module; the data processing module is used for receiving the excitation response signals and sine wave excitation signals of the tested equipment sent by the data acquisition module and sending signal generation instructions to the signal generation module. The method solves the problems of life safety and electrical safety caused by the fact that the existing impedance measurement method needs to be in direct contact with the running charged tested equipment or system during measurement.

Description

Non-contact on-line impedance measuring instrument

Technical Field

The present utility model relates to the field of electrical or electronic measurement.

Background

The non-contact on-line impedance measurement technology is an innovative electric or electronic measurement technology, and is mainly used for on-line measuring the impedance of electric or electronic equipment or systems. The development of this technology stems from the recognition of challenges and limitations of existing impedance measurement methods.

The existing impedance measurement methods mainly comprise a voltage or current method and a capacitive coupling method. Voltage/current methods, which require measuring the voltage and current of the system under test. By applying a signal processing algorithm, the impedance can be extracted from these measurements. However, the voltage/current method requires direct electrical contact with the charged system, which may present a certain electrical safety risk. Capacitive coupling methods that use a coupling capacitor to block a low frequency power supply signal while passing a high frequency test signal and then an impedance analyzer or vector network analyzer connected to the coupling capacitor performs an in-line impedance measurement. Similar to the voltage/current method, the capacitive coupling method also requires direct electrical contact with the charged device/system under test, which can present an electrical safety risk. Both of these existing measurement methods, while effective to some extent, present an inherent safety risk due to the need for direct contact with the operating charged device/system under test. Safety precautions must always be prioritized when handling such charged systems.

Disclosure of Invention

The utility model provides a non-contact type online impedance measuring instrument, which aims to solve the problem that the existing impedance measuring method needs to be in direct contact with running electrified tested equipment or a running electrified system during measurement and brings great risks to the life safety of workers and the electrical safety of equipment, and belongs to a measuring instrument for online electrical/electronic equipment or system impedance.

The technical scheme adopted by the utility model is as follows:

the non-contact online impedance measuring instrument is used for testing tested equipment, and the tested equipment is provided with a tested equipment lead (7) which comprises a clamp type inductive coupling probe (1), a data acquisition module (2), a signal generation module (3) and a data processing module (4);

the clamp type inductive coupling probe (1) comprises a receiving probe (12) and an injection probe (11); the receiving probe (12) and the injecting probe (11) are respectively clamped at two ends of the tested device lead (7),

the injection probe (11) is used for injecting the sine wave excitation signal generated by the signal generation module (3);

the receiving probe (12) is used for receiving an excitation response signal injected into the tested equipment;

the data acquisition module (2) is used for receiving an excitation response signal from the tested device, which is received by the receiving probe (12) in the clamp type inductive coupling probe (1), and also used for receiving a sine wave excitation signal sent by the injection probe (11), and the data acquisition module (2) is also used for sending the received excitation response signal of the tested device and the sine wave excitation signal to the data processing module (4);

the signal generation module (3) is used for sending sine wave excitation signals to the injection probe (11) and sending sine wave excitation signals to the data acquisition module (2);

the data processing module (4) is used for receiving the excitation response signal and the sine wave excitation signal of the tested equipment sent by the data acquisition module (2) and sending a signal generation instruction to the signal generation module (3).

Preferably, the clip-on inductive coupling probe (1) and the power supply (6) are separate external components.

Preferably, the receiving probe (12) and the injecting probe (11) are two independent inductive coupling probes or integrated inductive coupling probes.

Preferably, the data acquisition module (2) is a 14/16 bit conversion module, the speed of which is more than or equal to 125MSPS, and is used for converting analog signals input by the receiving probe (12) and the injection probe (11) into digital signals, and transmitting the digital signals to the data processing module (4).

Preferably, the signal generating module (3) consists of a 12/14-bit digital-to-analog converter for generating a sine wave excitation signal and transmitting the sine wave excitation signal to the injection probe (11).

Preferably, the data processing module (4) is a microprocessor, and is used for receiving the digital signal sent by the data acquisition module (2) and performing fast Fourier transform on the signal, and then calculating the on-line impedance of the tested equipment according to the processed signal according to the inductance coupling impedance measurement principle.

Preferably, the device further comprises a display module (5), wherein a display signal receiving end of the display module (5) is connected with an input end of the data processing module (4), and the display module (5) is used for displaying parameters.

Preferably, it further comprises a power supply (6), the power supply (6) comprising a DC-DC converter or an AC-DC converter operating with alternating current, the DC-DC converter or the AC-DC converter operating with alternating current providing voltages for the data acquisition module (2), the signal generation module (3) and the data processing module (4).

"non-contact": this term means that the impedance meter can measure impedance without directly connecting to the device under test. "on-line": this term means that the impedance meter can continuously measure the device impedance during operation of the device under test. "impedance measuring instrument": an impedance meter is an instrument used to measure impedance information of an electrical/electronic device or system. Impedance measurements may provide important information about the device/system performance under test.

The beneficial effects are that: the utility model discloses a non-contact type online impedance measuring instrument, which aims at solving the problem that the existing impedance measuring method needs to be in direct contact with running charged tested equipment or a system during measurement, and brings great risks to the life safety of staff and the electrical safety of equipment. The measuring instrument does not need to be in direct electrical contact with a system to be measured, so that the electrical safety risk is greatly reduced. Meanwhile, the technology also shows higher superiority in the aspects of accuracy, real-time performance and convenience of on-line measurement of the impedance of the electric/electronic equipment or the system:

1. improving electrical safety: by using a non-contact inductively coupled probe for impedance measurement, direct contact with the powered system is avoided, thereby significantly improving electrical safety. This is a significant advantage over conventional voltage-current and capacitive coupling methods, both of which require direct electrical contact with the charged system, presenting an electrical safety risk.

2. Measurement accuracy is improved: the data acquisition component can perform high-precision 14/16 bit conversion, the speed is at least 125MSPS, and the accuracy of a measurement result is ensured. In addition, the microprocessor unit of the present utility model can perform an accurate fast fourier transform on the digital signal and accurately calculate the impedance or determine the calibration parameters according to an algorithm, which is known in the art and not specifically described.

3. Measurement instantaneity and convenience are improved: the utility model realizes the on-line impedance measurement without stopping or powering off the tested equipment in the installation stage, and improves the real-time performance and convenience of the measurement. Moreover, all hardware components (data acquisition, signal generation and data processing) are integrated in one case, so that the operation and the use are convenient.

4. Easy interaction and control: the liquid crystal display screen component provides an interactive interface between a user and the instrument, displays measurement parameters including impedance, and accepts user input or commands, so that the operation and control process is simpler and more convenient.

Therefore, the non-contact type online impedance measurement equipment has higher electrical safety, measurement accuracy, real-time performance and convenience compared with the prior art.

Drawings

FIG. 1 is a schematic diagram of a non-contact on-line impedance meter;

FIG. 2 is a schematic diagram of a software configuration flow of the non-contact on-line impedance meter;

FIG. 3 is a measured on-line impedance of a 0.75kW TECO variable frequency drive system in the range of 150kHz-30MHz, with the graph being in differential mode;

FIG. 4 is a measured on-line impedance of a 0.75kW TECO variable frequency drive system in the range of 150kHz-30MHz, which is a common mode.

Detailed Description

The first embodiment is as follows: described with reference to fig. 1 to 4.

The non-contact on-line impedance measuring instrument mainly comprises six components: the device comprises a clamp type inductive coupling probe (1), a data acquisition module (2), a signal generation module (3), a data processing module (4), a display (5) and a power supply (6). The components (2) - (5) are integrated in one chassis. The components (1) and (6) are separate external components. Fig. 1 is a schematic diagram showing a hardware configuration.

There are two separate or integrated inductively coupled probes that are clamped to the wires of the device/system under test, one for injecting the sine wave excitation signal generated by the waveform generation assembly and the other for receiving the response signal injected into the device/system under test. The signal information at both probes is input to the data acquisition module. The utility model realizes non-contact on-line impedance measurement because the inductively coupled probe used is not in direct electrical contact with the device/system under test. In addition, the data acquisition module is capable of 14/16 bit conversion at a rate of at least 125MSPS. Its function is to convert the two input analog signals from the inductively coupled probe into digital signals, which are then presented to the data processing component. The waveform generation assembly consists of a 12/14 bit digital-to-analog converter. It is mainly used to generate a sine wave that is injected into one of the inductively coupled probes.

The data processing module is basically a microprocessor unit that receives digital signals, performs a fast fourier transform on the digital signals, and then processes the transformed output according to an algorithm. The algorithm calculates the impedance or determines the calibration parameters on command. The display assembly, as the name suggests, has a liquid crystal display screen that provides for interaction between the user and the instrument. It displays parameters, including impedance, and accepts input or commands. The power supply component is a battery operated DC-DC converter or an AC-DC converter operated by alternating current. It can be separated from the three components described above. Its function is to provide voltage and current for normal operation of the three hardware components.

Specific examples: in a variable frequency drive system, conducted electromagnetic interference noise generated by the switching action of the power semiconductor devices can propagate through its ac input side to the grid, thereby interfering with the operation of other parallel electrical devices. These conducted noises can be divided into common mode and differential mode noises. In order to be able to evaluate these noise components accurately, we need to construct corresponding common-mode and differential-mode noise models for the variable frequency drive system. Since these models are typically represented by equivalent noise sources with specific internal impedances, it becomes critical to extract the on-line common-mode and differential-mode impedances of these noise sources.

The measuring instrument according to the utility model can effectively fulfill this need. With the apparatus and measurement method of the present utility model we can measure the common mode (fig. 3) and differential mode (fig. 4) impedances of the variable frequency drive system in six different modes of operation on-line, as shown in fig. 3 and 4. Such embodiments clearly demonstrate the superiority and utility of the present utility model in practical applications.

The 6 different modes of operation control are as follows:

the utility model successfully solves the technical problems through a unique non-contact online impedance measurement technology and corresponding components. Firstly, the utility model avoids direct contact with an electrified system by adopting a non-contact inductive coupling probe, thereby greatly improving electrical safety. These inductively coupled probes are clamped on the wires of the device/system under test, one probe for injecting the excitation signal and the other probe for receiving the response signal of the device/system under test. Both probes interact with a data acquisition component configured in hardware. Secondly, the data acquisition component of the utility model can perform high-precision 14/16 bit conversion, and the rate is at least 125MSPS, which ensures the accuracy of the measurement result. At the same time, the waveform generation assembly generates a sine wave that is injected into one of the inductively coupled probes through a 12/14 bit digital-to-analog converter. The series of operations are completed in an integrated chassis, so that the convenience of the measurement process is realized. The data processing component then receives the digital signals and performs a fast fourier transform on the digital signals, and then processes the transformed output according to an algorithm. This microprocessor unit calculates the impedance or determines calibration parameters, thereby providing accurate and real-time impedance measurements. In addition, the liquid crystal display assembly provides an interactive interface between the user and the instrument. It displays the measured parameters, including impedance, and accepts user input or commands. Finally, the power supply component is a battery operated DC-DC converter or an AC-DC converter operated by alternating current. It provides voltage and current for normal operation of the three hardware components. Through the hardware configuration and the software configuration, the utility model effectively solves the electrical safety problem, improves the measurement accuracy, and improves the measurement instantaneity and convenience, thereby providing safer, more accurate and more convenient solutions for various electrical/electronic applications.

2. Novel software configuration

The software part mainly comprises a main task and four support tasks: (1) hardware control, (2) computation, (3) calibration, and (4) documentation. Fig. 2 shows all tasks and their interactions.

Fig. 2 is a software configuration of the present utility model, which includes the following steps: the master task initializes the four tasks (hardware control, calculation, calibration, file), starts the task, and then enters a perpetual loop. In this perpetual loop, it sends a signal to the hardware control task to initiate data acquisition, then to the calculation task to perform FFT (fast fourier transform) operations on the acquired data, then to calculate the impedance or to send a signal and processed data to the calibration task to perform the calibration process. Finally, it may signal parameters or data required for file manipulation task preservation. The hardware control task sets hardware, and then repeatedly performs data acquisition under the direction of the main task. During initialization, it also sets the DAC output sine waveform. When the computing task receives the signal, it obtains raw data from the hardware control task. From the raw data, it calculates the FFT of the two signals and then uses these results to calculate the impedance from the equation or pass the results to a calibration task. When the calibration task is invoked, it calculates the constants used in the impedance equation. This is an important step because the accuracy of measuring the impedance depends on these constants. When data (raw data or calibration data) needs to be saved, the file task will be invoked.

The problems to be solved are as follows:

the technical problem that mainly solves: improving electrical safety: as previously mentioned, existing in-line impedance measurement techniques, such as voltage-current methods and capacitive coupling methods, all require direct electrical contact with the device/system under test. Such direct contact charged devices/systems may present an electrical safety risk.

It is therefore a primary object of the present utility model to develop a novel non-contact on-line impedance measurement technique and instrument to avoid direct contact with the charged equipment/system, thereby significantly improving electrical safety.

The technical problem to be solved secondarily is as follows: 1) Measurement accuracy is improved: existing online impedance measurement methods may suffer from factors that reduce the accuracy of the measurement results, particularly the accuracy of impedance measurements at higher frequencies. A secondary object of the present utility model is to improve the accuracy of impedance measurements to provide more reliable impedance information of the device/system under test. 2) Real-time and convenience of measurement are improved: due to the limitations of the prior art, current impedance measurements may not be performed in real-time or in a convenient manner. It is another object of the present utility model to develop a technique and apparatus that can measure the impedance of an electrical/electronic component or system in real time and conveniently.

By addressing these issues, the non-contact online impedance measurement technique of the present utility model will provide a safer, more accurate, and more convenient solution for a variety of electrical/electronic applications.

While the utility model has been described with reference to several particular embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the utility model. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the utility model without departing from its scope. Therefore, it is intended that the utility model not be limited to the particular embodiment disclosed, but that the utility model will include all embodiments falling within the scope of the appended claims.

Claims

1. The non-contact online impedance measuring instrument is used for testing tested equipment, and the tested equipment is provided with a tested equipment lead (7), and is characterized by comprising a clamp type inductive coupling probe (1), a data acquisition module (2), a signal generation module (3) and a data processing module (4);

2. The non-contact on-line impedance meter according to claim 1, wherein the clip-on inductively coupled probe (1) and the power supply (6) are separate external components.

3. The non-contact on-line impedance meter according to claim 1, wherein the receiving probe (12) and the injection probe (11) are two separate inductively coupled probes or an integrated inductively coupled probe.

4. The non-contact on-line impedance meter according to claim 1, wherein the data acquisition module (2) is a 14/16 bit conversion module with a rate of 125MSPS or more, and is configured to convert analog signals input by the receiving probe (12) and the injection probe (11) into digital signals, and send the digital signals to the data processing module (4).

5. The non-contact on-line impedance meter according to claim 1, wherein the signal generating module (3) consists of a 12/14-bit digital-to-analog converter for generating a sine wave excitation signal and transmitting it to the injection probe (11).

6. The non-contact on-line impedance measuring instrument according to claim 1, wherein the data processing module (4) is a microprocessor, and is configured to receive the digital signal sent by the data acquisition module (2), perform fast fourier transform on the signal, and calculate on-line impedance of the device under test according to the inductance coupling impedance measurement principle based on the processed signal.

7. The non-contact on-line impedance measuring instrument according to claim 1, further comprising a display module (5), wherein a display signal receiving end of the display module (5) is connected to an input end of the data processing module (4), and the display module (5) is used for displaying parameters.

8. The non-contact on-line impedance meter according to claim 1, further comprising a power supply (6), the power supply (6) comprising a DC-DC converter or an AC-DC converter operating with alternating current, the DC-DC converter or the AC-DC converter operating with alternating current providing voltages for the data acquisition module (2), the signal generation module (3) and the data processing module (4).