Wireless flexible clamp meter

Abstract

The utility model discloses a wireless flexible clamp meter used for current and voltage detection, a current clamp of the clamp meter is a flexible Rogowski coil, the flexible Rogowski coil is connected to a current sampling circuit, the current sampling circuit is connected to an integrating circuit, the integrating circuit is connected to a first signal amplification circuit, and the first signal amplification circuit is connected to a second signal amplification circuit. The first signal amplification circuit is connected to the first AC-DC conversion circuit and the first frequency phase detection circuit, the first AC-DC conversion circuit and the first frequency phase detection circuit are connected to the single-chip microcomputer, the single-chip microcomputer is connected to the liquid crystal display screen and the communication module, and the communication module at least comprises a wireless communication module. The wireless communication module is provided with a communication interface used for carrying out wireless signal interaction with a handheld end. The flexible Rogowski coil is used as a current clamp, and the Rogowski coil is an annular coil uniformly wound on a non-ferromagnetic material, so that the magnetic hysteresis effect is avoided, the phase error is almost zero, the magnetic saturation phenomenon is avoided, the linearity is high, and the anti-interference capability is strong.

Description

TECHNICAL FIELD

[0001] The utility model relates to a current clamp meter, more specifically, the utility model mainly relates to a wireless flexible clamp meter for current and voltage detection. BACKGROUND

[0002] In the fields of electric power, communication, meteorology, railway, oil field, building, measurement, scientific research and teaching unit, mining enterprise and the like, voltage and current clamp meters are needed to test AC current, large current and leakage current on site, however, the current clamp meter is limited by its structure, collects external current through a current transformer, is affected by its own impedance, and is not easy to obtain linear stable collection signal, thereby affecting the accuracy of voltage or current collection of external circuit facilities, so it is necessary to further research and improve the circuit structure of the same kind of current and voltage clamp meter; at the same time, in order to cope with the measurement scene of some needs, improve the work efficiency of the measurement personnel, provide a wireless communication interface for wirelessly connecting the current clamp, and read the voltage, current, frequency, phase, power and other electric parameter data. SUMMARY

[0003] One of the purposes of the utility model is to provide a wireless flexible clamp meter for current and voltage detection in order to solve the technical problems that the same kind of current clamp meter in the prior art is limited by single machine measurement and its own impedance, cannot wirelessly obtain measurement data, is not easy to obtain linear stable collection signal, and thereby affects the accuracy of voltage or current collection of external circuit facilities.

[0004] To solve the above technical problems, the utility model adopts the following technical scheme:

[0005] The utility model provides a wireless flexible clamp meter, the current clamp of the clamp meter is a flexible Rogowski coil, the flexible Rogowski coil is connected to a current sampling circuit, the current sampling circuit is connected to an integration circuit, the integration circuit is connected to a first signal amplification circuit, the first signal amplification circuit is connected to a first AC-DC conversion circuit and a first frequency phase detection circuit respectively, the first AC-DC conversion circuit and the first frequency phase detection circuit are connected to a single-chip microcomputer, the single-chip microcomputer is connected to a liquid crystal display screen and a communication module respectively, the communication module at least includes a wireless communication module, the wireless communication module has a communication interface for wireless signal interaction with a handheld end; the current sampling circuit includes an analog switch and a sampling resistor, is used for switching the sampling resistor through the sampling resistor needed by different current size, and is controlled by the IO port of the master control chip to control the on-off of the mos tube, and then switches the sampling resistor; the integration circuit is used for converting the voltage signal converted by the current sampling circuit into a detectable voltage signal; the first signal amplification circuit is used for amplifying the current signal through different amplification gain and outputting to the single-chip microcomputer.

[0006] As preferred, the further technical scheme is: the wireless flexible clamp meter further comprises a voltage sampling circuit, the voltage sampling circuit is used for accessing a voltage test line, the voltage test line accesses an external voltage to the voltage sampling circuit, the voltage sampling circuit accesses a second AC-DC conversion circuit and a second frequency phase detection circuit through a second signal amplification circuit respectively, and the second AC-DC conversion circuit and the second frequency phase detection circuit both access a single-chip microcomputer; the voltage sampling circuit also comprises an analog switch and a sampling resistor, and is used for switching the sampling resistor by controlling the on-off of a mos transistor through an IO port of a master chip according to the required sampling resistor at different voltage sizes; and the second signal amplification circuit is used for amplifying the voltage signal through different amplification gains and outputting to the single-chip microcomputer.

[0007] The further technical scheme is: the first AC-DC conversion circuit is used for converting the collected alternating current signal into a direct current voltage signal for AD collection; and the first frequency phase detection circuit is used for performing full-wave rectification on the front-stage current signal, inverting the negative half cycle of the signal, and then detecting the frequency and phase of the current signal.

[0008] The further technical scheme is: the second AC-DC conversion circuit is used for converting the collected alternating voltage signal into a direct current voltage signal for AD collection; and the second frequency phase detection circuit is used for performing full-wave rectification on the front-stage voltage signal, inverting the negative half cycle of the signal, and then detecting the frequency and phase of the voltage signal.

[0009] Compared with the prior art, one of the beneficial effects of the utility model is that: by adopting the flexible Rogowski coil as the current clamp, since the Rogowski coil is a ring-shaped coil uniformly wound on a non-ferromagnetic material, has no magnetic hysteresis effect, almost zero phase error, no magnetic saturation phenomenon, and high linearity, and has strong anti-interference ability. Therefore, the clamp meter output signal is the differential of the current with respect to time, and by integrating the output voltage signal, the input current can be truly restored, and the test current range can be from the milliamper level to tens of thousands of amperes. By accessing the wireless communication module, the current clamp can be used as a voltage and current monitoring instrument, the measurement data of multiple current clamps can be acquired through the wireless receiver, and wireless monitoring of the voltage and current can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 It is a structural schematic diagram for explaining one embodiment of the utility model.

[0011] Figure 2 It is a circuit structure schematic block diagram for explaining one embodiment of the utility model.

[0012] In the drawing, 1 is a meter body, and 2 is a current clamp. DETAILED DESCRIPTION

[0013] The utility model will be further described below with reference to the drawings.

[0014] Reference Figure 1 As shown in the utility model, the flexible clamp ammeter is innovative in structure design, and the coil is opened and closed like a ballpoint pen, which is very convenient, and is designed and manufactured for testing AC current, large current and leakage current on site. It is widely used in the fields of electric power, communication, meteorology, railway, oil field, building, measurement, scientific research and teaching units, industrial and mining enterprises, etc. It is especially suitable for current testing in places with dense wiring, transformer wall grounding core current testing, thick wire cable testing, relay protection, silicon controlled rectifier, frequency conversion speed regulation, semiconductor switch, power electronic conversion equipment, arc welding and other signal severely distorted industrial environments.

[0015] The current clamp of the wireless flexible clamp meter is Rogowski Coil, which adopts advanced Rogowski Coil technology, is a ring-shaped coil uniformly wound on a non-ferromagnetic material, has no magnetic hysteresis effect, almost zero phase error, no magnetic saturation phenomenon, high linearity and strong anti-interference ability. The output signal is the differential of current with respect to time, and by integrating the output voltage signal, the input current can be truly restored, and the test current range can be from milliamperes to tens of thousands of amperes.

[0016] The instrument handle adopts double-color injection molding: the appearance is exquisite, the hand feeling is first-class, the volume is small, the weight is light, the coil part has no any bare metal conductor, the coil is soft and flexible, non-contact testing, safe and fast, ensures high precision and reliability of measurement, and has wide response frequency band, and the user can also customize the coil length according to the demand to meet the testing of different wire diameters. The instrument has the functions of Bluetooth communication, current peak retention, data retention, data storage, USB serial communication, etc., and is an essential tool for electrician safety detection.

[0017] In combination Figure 2As shown, in an embodiment of the utility model, the current clamp of wireless flexible clamp meter is flexible Rogowski coil, it includes current sampling circuit, voltage sampling circuit, integration circuit, signal amplification circuit, AC-DC conversion circuit, frequency phase detection circuit, wireless communication circuit, bluetooth communication circuit, serial communication circuit. Specifically, the foregoing flexible Rogowski coil accesses current sampling circuit, current sampling circuit accesses integration circuit, integration circuit accesses first signal amplification circuit, first signal amplification circuit accesses first AC-DC conversion circuit and first frequency phase detection circuit respectively, first AC-DC conversion circuit and first frequency phase detection circuit all access single-chip microcomputer, single-chip microcomputer accesses liquid crystal display and communication module respectively, the communication module at least includes wireless communication module, and wireless communication module has communication interface for carrying out wireless signal interaction with handheld end.

[0018] The current sampling circuit includes analog switch and sampling resistor, and is used for switching the sampling resistor by controlling the on-off of the MOS transistor through the IO port of the main control chip according to the required sampling resistor for different current sizes.

[0019] The integration circuit is used for converting the voltage signal converted by the current sampling circuit into a detectable voltage signal.

[0020] The first signal amplification circuit is used for amplifying the current signal by different amplification gains and outputting to the single-chip microcomputer.

[0021] Further, the first AC-DC conversion circuit is used for converting the collected alternating current signal into a direct current voltage signal for AD collection, and the first frequency phase detection circuit is used for full-wave rectifying the current signal of the previous stage, inverting the negative half cycle of the signal, and then detecting the frequency and phase of the current signal.

[0022] According to another embodiment of the utility model, the wireless flexible clamp meter further includes a voltage sampling circuit, the voltage sampling circuit is used for accessing the voltage test line, the voltage test line accesses the external voltage into the voltage sampling circuit, and the voltage sampling circuit accesses the second AC-DC conversion circuit and the second frequency phase detection circuit through the second signal amplification circuit respectively, and the second AC-DC conversion circuit and the second frequency phase detection circuit all access the single-chip microcomputer; the voltage sampling circuit also includes analog switch and sampling resistor, and is used for switching the sampling resistor by controlling the on-off of the MOS transistor through the IO port of the main control chip according to the required sampling resistor for different voltage sizes; the second signal amplification circuit is used for amplifying the voltage signal by different amplification gains and outputting to the single-chip microcomputer.

[0023] Specifically, the second AC-DC conversion circuit is configured to convert the collected AC voltage signal into a DC voltage signal for AD collection; and the second frequency and phase detection circuit is configured to perform full-wave rectification on the front-stage voltage signal, flip the negative half cycle of the signal, and then detect the frequency and phase of the current voltage signal.

[0024] As mentioned in the above embodiments, Figure 2 The original circuit is as follows:

[0025] The current sampling circuit is composed of an analog switch and a sampling resistor. For different sizes of sampling resistors required for different current sizes, an analog switch circuit is designed using a MOS tube, which has low on-resistance. The MOS tube is controlled by the IO port of the master control chip to switch the sampling resistor.

[0026] The voltage sampling circuit: the principle is similar to the current sampling circuit. The switching of the sampling resistor is realized by the switch of the MOS tube.

[0027] The integration circuit: the sampled voltage signal is very small, and is integrated by the designed integration circuit to become a detectable voltage signal. In order to solve the phase offset generated by the integration circuit, the circuit is designed and debugged to make the current-voltage phase error close to 0.

[0028] The signal amplification circuit: the sampling current and voltage signals of the front stage are amplified. Different amplification gains are used at different voltage or current sizes to provide a large enough voltage amplitude for chip AD sampling.

[0029] The AC-DC conversion circuit: the collected AC voltage and current signals are converted into DC current and voltage signals that can be stably collected by AD.

[0030] The frequency and phase detection circuit: the front-stage current and voltage signals are full-wave rectified, and the negative half cycle of the signal is flipped to efficiently utilize the entire cycle waveform for frequency and phase measurement.

[0031] The wireless communication module: provides a communication interface to facilitate secondary development of a handheld display device. After the instrument is installed, the measurement data can be wirelessly viewed, and data saving and reading can be realized.

[0032] The Bluetooth module: used for connecting with the mobile phone APP for data monitoring and data uploading.

[0033] The serial communication circuit: used for connecting with the computer for data reading.

[0034] Flexible coil: the flexible coil is different from the AC current transformer in that its magnetic core is different, the flexible coil is an air core, has lower insertion impedance, faster signal response and linear signal voltage, and thus has the advantages of no magnetic saturation, low phase shift, and bendable clamp head, which are not available in different current clamps.

[0035] In addition to the above, it should also be noted that the "one embodiment", "another embodiment", "embodiment" and the like mentioned in the specification refer to the specific features, structures or characteristics described in connection with the embodiment, which are included in at least one embodiment described in the general description of the application. The same expression appearing in several places in the specification does not necessarily refer to the same embodiment. Further, when a specific feature, structure or characteristic is described in connection with any embodiment, it is claimed that the implementation of such feature, structure or characteristic in connection with other embodiments also falls within the scope of the present application.

[0036] Although the present application has been described herein with reference to the various illustrative embodiments thereof, it should be understood that various other modifications and implementations can be devised by those skilled in the art, which will fall within the principles of the present application. More specifically, various modifications and improvements can be made to the components of the subject combination layout and / or the layout itself, within the scope of the present application, drawings and claims. In addition to the modifications and improvements to the components and / or layout, other uses will also be apparent to those skilled in the art.

Claims

1. A wireless flexible clamp meter, characterized in that: The clamp meter's current clamp is a flexible Rogowski coil. The flexible Rogowski coil is connected to a current sampling circuit, which is connected to an integration circuit. The integration circuit is connected to a first signal amplification circuit, which is connected to a first AC / DC conversion circuit and a first frequency phase detection circuit. Both the first AC / DC conversion circuit and the first frequency phase detection circuit are connected to a microcontroller. The microcontroller is connected to an LCD screen and a communication module. The communication module includes at least a wireless communication module and has a communication interface for wireless signal interaction with a handheld device. The current sampling circuit includes an analog switch and a sampling resistor, which are used to sample the current required for different current magnitudes. The MOSFET is switched on and off by the main control chip's I / O port, thereby switching the sampling resistor. The integrating circuit is used to convert the voltage signal obtained by the current sampling circuit into a detectable voltage signal. The first signal amplification circuit is used to amplify the current signal through different amplification gains and output it to the microcontroller.

2. The wireless flexible clamp meter according to claim 1, characterized in that: The wireless flexible clamp meter also includes a voltage sampling circuit, which is used to connect to a voltage test line. The voltage sampling circuit is connected to a second AC / DC conversion circuit and a second frequency phase detection circuit through a second signal amplification circuit. Both the second AC / DC conversion circuit and the second frequency phase detection circuit are connected to a microcontroller. The voltage sampling circuit also includes an analog switch and a sampling resistor, which are used to switch the sampling resistor according to the required sampling resistor for different voltage magnitudes. The main control chip's I / O port controls the on / off state of the MOSFET, thereby switching the sampling resistor. The second signal amplification circuit is used to amplify the voltage signal with different amplification gains and output it to the microcontroller.

3. The wireless flexible clamp meter according to claim 1 or 2, characterized in that: The first AC / DC conversion circuit is used to convert the acquired AC current signal into a DC voltage signal that can be acquired by the AD converter; the first frequency and phase detection circuit is used to perform full-wave rectification on the previous current signal, flip the negative half-cycle of the signal, and then detect the frequency and phase of the current signal.

4. The wireless flexible clamp meter according to claim 2, characterized in that: The second AC / DC conversion circuit is used to convert the acquired AC voltage signal into a DC voltage signal that can be acquired by the AD converter; the second frequency and phase detection circuit is used to perform full-wave rectification on the previous voltage signal, flip the negative half-cycle of the signal, and then detect the frequency and phase of the current voltage signal.

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