Cable system for accurately measuring output current of direct-current power supply

Abstract

A direct-current power supply output current accurate measurement cable system comprises a cable body, a low-resistance standard resistor is connected to the cable body in series, the cable body and the standard resistor are in insulation connection through an insulation thermal shrinkage sleeve, and the standard resistor and a conductor in a cable are detachably connected in parallel through a quick-change connector. Voltage measuring terminals are arranged at the two ends of the standard resistor and are used for being externally connected with a high-precision voltmeter; according to the utility model, the low-resistance standard resistor is connected in series on the cable, and the external high-precision voltmeter is combined, so that accurate measurement of the output current of the direct-current power supply is realized; the system further comprises a measurement and control device which can display the current waveform in real time, improve the current waveform, protect electrical equipment and prevent the cable from being overheated. The direct-current power supply current measuring device is safe and reliable, improves the accuracy and convenience of direct-current power supply current measurement in the overhaul and maintenance of power equipment, meets the requirements of electrical tests with requirements on current measurement precision, and is particularly suitable for electrical equipment tests and electric welding occasions requiring high-precision current measurement.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical measurement, in particular to a direct current power supply output current accurate measurement cable system. Background Art

[0002] In applications such as electrical equipment testing and electric welding, DC power supplies are key equipment that provide stable DC current for various tasks. However, in these application scenarios, there are often high requirements for current measurement accuracy to ensure the accuracy of the test and the quality of welding. However, the ammeter that comes with the DC power supply has the following problems:

[0003] 1) Low accuracy: The ammeter that comes with the DC power supply often cannot meet the requirements of high-precision testing due to cost, design and other reasons;

[0004] 2) Long-term inaccuracy due to uncalibrated operation: During long-term use, the ammeter may become inaccurate due to environmental factors, aging, etc., further reducing its measurement accuracy.

[0005] 3) Non-removable and difficult to calibrate: The ammeter that comes with the DC power supply is usually not removable, making it difficult to calibrate it regularly and to ensure its long-term accuracy.

[0006] As a direct connection between the DC power supply and the device under test or welding equipment, the DC cable undertakes the important task of transmitting current and is an indispensable component in the DC circuit. The performance of the cable directly affects the efficiency and stability of current transmission, and thus affects the working effect of the entire circuit.

[0007] Therefore, developing a DC power supply output current precise measurement cable system to improve the accuracy and convenience of current measurement in power equipment overhaul and maintenance is of great significance and high practical application value for improving current measurement accuracy and ensuring the stability and safety of circuit operation. Summary of the invention

[0008] The technical problem to be solved by the utility model is to provide a cable system for accurately measuring the output current of a DC power supply, so as to solve the problems that the ammeter provided by the existing DC power supply has low measurement accuracy, is difficult to calibrate and cannot be disassembled, and the cable performance in the DC line cannot be monitored.

[0009] In order to solve the above technical problems, the technical solution adopted by the utility model is: a DC power supply output current accurate measurement cable system, which includes a cable body, a low-resistance standard resistor is connected in series on the cable body, the cable body and the standard resistor are insulated and connected by an insulating heat shrink sleeve, the standard resistor and the conductor inside the cable are connected in parallel in a detachable manner by a quick-change connector, voltage measurement terminals are set at both ends of the standard resistor for an external measurement and control device, and a high-precision voltmeter is set on the measurement and control device.

[0010] In a preferred solution, the resistance range of the low-resistance standard resistor is in the micro-ohm range to ensure that the current carrying capacity of the cable is not affected when measuring the output current of the DC power supply.

[0011] In a preferred solution, the measurement accuracy of the high-precision voltmeter is at the millivolt level, and is used to accurately measure the voltage across a standard resistor, thereby calculating the precise value of the output current of the DC power supply according to Ohm's law.

[0012] In a preferred solution, one end of the cable body is connected to the output end of the DC power supply, and the other end is connected to the input end of the electrical device to be tested.

[0013] In a preferred solution, the quick connector adopts a plug-in or threaded connection method to facilitate the replacement and calibration of the standard resistor.

[0014] In a preferred solution, the cable body is also provided with a DC switch and a temperature measuring resistor which are connected in series with a standard resistor.

[0015] In a preferred solution, the measurement and control device further includes:

[0016] An interface connected to an oscilloscope, which displays and analyzes the current waveform in real time;

[0017] A current detection module is used to detect the current value in the cable body in real time;

[0018] The current control module is in communication with the DC power supply and is used to send a feedback signal to the DC power supply to improve the waveform when it is detected that the current ripple factor is too large.

[0019] In a preferred solution, the measurement and control device further includes a DC switch control module connected to the DC switch and configured to disconnect the DC switch when an excessive current is detected, so as to protect the electrical equipment under test.

[0020] In a preferred solution, the measurement and control device also includes a temperature detection module connected to the temperature measuring resistor for real-time monitoring of the cable body temperature.

[0021] In a preferred solution, the measurement and control device also includes an alarm module, which issues an overheating warning and controls the DC switch to disconnect when the temperature of the cable body exceeds a preset threshold.

[0022] The utility model provides a direct current power supply output current accurate measurement cable system, which has the following beneficial effects:

[0023] 1. The utility model solves the problems that the current meter of the existing DC power supply has low measurement accuracy, is difficult to detach and calibrate, and the performance of the cable in the DC line cannot be monitored;

[0024] 2. The utility model ensures the accuracy of current measurement, improves the safety and flexibility of the system by connecting a low-resistance standard resistor in series in the cable and measuring it with an external high-precision voltmeter;

[0025] 3. The utility model selects a standard resistor in the micro-ohm level as the current sampling component, ensuring the minimum impact on the circuit, not affecting the normal flow of current, and providing high-precision current measurement;

[0026] 4. The utility model can externally connect a high-precision voltmeter through the reserved voltage measurement terminal, and the voltmeter can be replaced or calibrated at any time to ensure the accuracy of the measurement result, which is particularly applicable to scenarios that require regular calibration or work under different precision requirements;

[0027] 5. The voltmeter of the utility model selects a high-precision voltmeter with a measurement accuracy of millivolt level, and calibrates the high-precision voltmeter through an internal calibration circuit to ensure the accuracy of the measurement result, which is used to accurately measure the voltage across the standard resistor, and then calculate the accurate value of the DC power supply output current according to Ohm's law;

[0028] 6. The design of the utility model integrates a measurement and control device, which can monitor parameters such as current waveform and temperature in real time. Once abnormalities are found, such as too high current ripple coefficient or overheating of the cable, it can timely feedback to the DC power supply to adjust the output or directly disconnect the circuit, effectively preventing potential safety risks;

[0029] 7. The settings of each module in the measurement and control device of the utility model can accurately measure the accurate value of the DC power supply output current and display the current waveform in real time, which is beneficial to analyzing the current waveform and ensuring the current quality; at the same time, by setting a temperature detection and alarm module, the temperature of the cable body can be monitored in real time, and the power supply can be automatically disconnected when the temperature is too high to ensure the safety and reliability of the system;

[0030] 8. The utility model not only solves the problem of insufficient measurement accuracy of the existing DC power supply, but also improves the overall performance of the system through a series of innovative measures, improves the accuracy and convenience of current measurement in the maintenance of power equipment, and has important significance for improving current measurement accuracy and ensuring the stability and safety of circuit operation, and has high practical value and promotion potential in the field of electrical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The following further describes the utility model in conjunction with the drawings and embodiments:

[0032] Figure 1 is the overall structural schematic diagram of the utility model;

[0033] Figure 2 is the isometric front view of the overall structure of the utility model;

[0034] In the figure: standard resistor 1, measurement terminal 2, cable body 3, measurement and control device 4, oscilloscope 5, DC switch 6, temperature measurement resistor 7, DC power supply 8, rotor winding 9. Specific implementation mode

[0035] The technical solution of the present utility model will be further described below with reference to the accompanying drawings:

[0036] Embodiment 1

[0037] As Figures 1-2 shown, a DC power supply output current precise measurement cable system includes a cable body 3, a low-resistance standard resistor 1 is connected in series on the cable body 3, the cable body 3 and the standard resistor 1 are insulated and connected by an insulating heat shrinkable sleeve, and the standard resistor 1 and the conductor inside the cable are connected in parallel by a quick-change joint and can be detachably connected together. Voltage measurement terminals 2 are arranged at both ends of the standard resistor 1 for externally connecting a measurement and control device 4, and a high-precision voltmeter is arranged on the measurement and control device 4.

[0038] In this embodiment, the resistance value range of the low-resistance standard resistor 1 is in the micro-ohm level to ensure that the over-current capacity of the cable is not affected when measuring the output current of the DC power supply 8.

[0039] Furthermore, the measurement accuracy of the high-precision voltmeter is in the millivolt level, which is used to accurately measure the voltage across the standard resistor 1, so as to calculate the accurate value of the output current of the DC power supply 8 according to Ohm's law.

[0040] Furthermore, one end of the cable body 3 is connected to the output end of the DC power supply 8, and the other end is connected to the input end of the electrical equipment to be measured.

[0041] Furthermore, the quick joint adopts a plug-in or threaded connection method to facilitate the replacement and calibration of the standard resistor 1.

[0042] During specific use, after the entire system is installed and debugged qualified, one end of the cable body 3 is connected to the output end of the DC power supply 8, and the other end is connected to the input end of the electrical equipment to be measured. The measurement end of the high-precision voltmeter is connected to the voltage measurement terminal 2 on the cable, and the voltage value across the standard resistor 1 is measured through the voltmeter; according to Ohm's law I = U / R, where U is the voltage value measured by the voltmeter and R is the known resistance value of the standard resistor 1, the accurate value of the output current of the DC power supply 8 can be calculated.

[0043] When it is necessary to calibrate or replace the standard resistor 1, only need to separate the standard resistor 1 from the cable conductor through the quick joint, and then the calibration or replacement operation can be carried out; this detachable design makes the calibration work simple and convenient, improving the work efficiency.

[0044] Embodiment 2

[0045] In another preferred embodiment, on the basis of the above-mentioned Embodiment 1, a DC switch 6 and a temperature-measuring resistor 7 connected in series with the standard resistor 1 are further provided on the cable body 3.

[0046] Furthermore, the measurement and control device 4 further includes:

[0047] An interface connected to the oscilloscope 5, and the oscilloscope 5 displays and analyzes the current waveform in real time;

[0048] A current detection module for real-time detection of the current value in the cable body 3;

[0049] A current control module, which communicates with the DC power supply 8, and is used to send a feedback signal to the DC power supply 8 to improve the waveform when it detects that the current ripple coefficient is too large.

[0050] Furthermore, the measurement and control device 4 further includes a DC switch control module, which is connected to the DC switch 6 and is used to disconnect the DC switch 6 when it detects that the current is too large to protect the electrical equipment to be tested.

[0051] Furthermore, the measurement and control device 4 further includes a temperature detection module, which is connected to the temperature-measuring resistor 7 and is used to monitor the temperature of the cable body 3 in real time.

[0052] Furthermore, the measurement and control device 4 further includes an alarm module, which issues an overheat warning and controls the DC switch 6 to disconnect when the temperature of the cable body 3 exceeds a preset threshold.

[0053] During specific use, taking the measurement of the DC resistance and the joint resistance of the rotor winding 9 of the generator set as an example, the cable system of the present invention is used to connect the DC power supply 8 and the rotor winding 9, and the functions of each part of the system are realized as follows:

[0054] (1) Measurement of current and resistance

[0055] First, a current is passed through the rotor winding 9 by the DC power supply 8, and then the generated voltage U is measured using a voltmeter, and the resistance value R of a standard resistor 1 is known.

[0056] Specifically, the DC power supply 8 is connected to the rotor winding 9, and the current source is set and adjusted to pass a predetermined current; the voltmeter is connected across the two ends of the rotor winding 9, and the measured voltage U is recorded.

[0057] According to Ohm's law I = U / R, since the resistance value R of the standard resistor 1 is known, the accurate value of the current I passed through the rotor winding 9 can be calculated. It should be noted here that although R is mentioned as the resistance value of the standard resistor 1, in actual measurement, the standard resistor 1 is usually used for calibration rather than directly participating in the current calculation. Therefore, R here should be understood as the equivalent resistance of the rotor winding 9 and its joints.

[0058] (2)Monitoring and adjustment of current waveform

[0059] The measurement and control device 4 is connected to the oscilloscope 5 to display the current waveform in real time. If the current ripple coefficient is too large (i.e., the waveform is unstable), the current detection module of the measurement and control device 4 will send a signal to the DC power supply 8 to improve the waveform.

[0060] Specifically, connect the measurement and control device 4 to the oscilloscope 5 and ensure that the current waveform can be displayed in real time.

[0061] The current detection module monitors the current waveform on the oscilloscope 5. If the ripple coefficient is too large, it indicates that the current is unstable.

[0062] The current detection module of the measurement and control device 4 automatically or manually adjusts the output parameters of the DC power supply 8 according to the feedback of the oscilloscope 5 to improve the current waveform and ensure its stability and compliance with requirements.

[0063] (3)Overcurrent protection

[0064] The measurement and control device 4 is connected to the DC switch 6. When excessive current is detected, the switch will be automatically disconnected to protect the equipment from damage.

[0065] During the process, the measurement and control device 4 continuously monitors the current value. If the current exceeds the preset threshold (i.e., overcurrent), the DC switch control module of the measurement and control device 4 will immediately send a disconnection signal to the DC switch. After receiving the disconnection signal, the DC switch 6 quickly cuts off the circuit to prevent damage to the equipment caused by overcurrent.

[0066] (4)Overheat protection

[0067] The measurement and control device 4 is connected to the temperature measuring resistor 7 to monitor the cable temperature in real time; when the cable is detected to be overheated, the DC switch 6 will be automatically disconnected to prevent the cable from being damaged due to overheating.

[0068] During the process, the temperature detection module of the measurement and control device 4 monitors the cable temperature in real time through the temperature measuring resistor 7. If the cable temperature exceeds the preset threshold (i.e., overheat), the alarm module of the measurement and control device 4 will alarm and send a disconnection signal to the DC switch 6 through the temperature detection module. After receiving the disconnection signal, the DC switch 6 quickly cuts off the circuit to avoid fires or other safety accidents caused by cable overheating.

[0069] This new type realizes the accurate measurement and verification of the output current of the DC power supply 8, improving the accuracy and convenience of current measurement in the maintenance of power equipment; in addition, the cable body 3 is connected to the measurement and control device 4 to monitor the current waveform, current magnitude and cable temperature in real time; when the current ripple coefficient is too large, the current is too large or the cable is overheated, the measurement and control device 4 can automatically disconnect the DC switch 6 to protect the safety of the circuit and equipment, providing strong support for applications such as the maintenance of electrical equipment and electric welding.

[0070] In a preferred embodiment, the resistance value range of the low-resistance standard resistor 1 is in the micro-ohm level to ensure that the over-current capacity of the cable is not affected when measuring the output current of the DC power supply 8. The above setting can effectively avoid imposing an extra burden on the circuit during measurement, improving the accuracy and reliability of the measurement. At the same time, the selection of the low-resistance standard resistor 1 also fully considers the requirements of the actual application scenario, making it have good versatility and practicality.

[0071] In a preferred embodiment, the measurement accuracy of the high-precision voltmeter is in the millivolt level, which is used to accurately measure the voltage across the standard resistor 1, and then calculate the accurate value of the output current of the DC power supply 8 according to Ohm's law. The above setting can ensure the accuracy and reliability of the measurement result. At the same time, the high-precision voltmeter also has characteristics such as fast response and high stability, which can meet the measurement requirements in various application scenarios.

[0072] In a preferred embodiment, one end of the cable body 3 is connected to the DC power supply 8, and the other end is connected to the electrical equipment to be measured. With the above setting, the DC power supply 8 can output a stable DC current, thereby accurately testing the current of the electrical equipment to be measured. The cable body 3 has good electrical conductivity and can effectively transmit the DC current, ensuring the accuracy and reliability of the test.

[0073] In a preferred embodiment, the quick connector adopts a plug-in or threaded connection method to facilitate the replacement and calibration of the standard resistor 1. The above setting not only improves the flexibility of the equipment but also ensures the accuracy and stability of the measurement. In addition, the resistance value range of the standard resistor 1 can be adjusted according to actual needs to meet the requirements of different application scenarios.

[0074] In a preferred embodiment, a DC switch 6 and a temperature-measuring resistor 7 connected in series with the standard resistor 1 are also provided on the cable body 3. With the above setting, when the cable body 3 is working, the series connection and disconnection of the standard resistor 1 and the temperature-measuring resistor 7 can be realized by controlling the on-off of the DC switch 6, so as to facilitate the real-time monitoring and control of the resistance value and temperature of the cable body 3.

[0075] In a preferred embodiment, the measurement and control device 4 further includes: an interface connected to the oscilloscope 5, and the oscilloscope 5 displays and analyzes the current waveform in real time; a current detection module for detecting the current value in the cable body 3 in real time; a current control module communicating with the DC power supply 8, which is used to send a feedback signal to the DC power supply 8 to improve the waveform when the detected current ripple coefficient is too large. The above setting can effectively realize the real-time monitoring of the cable current waveform and improve the current stability. When the detected current ripple coefficient exceeds the preset threshold, the current control module will send a feedback signal in time, causing the DC power supply 8 to adjust the output current, thereby optimizing the current waveform.

[0076] In a preferred solution, the measurement and control device 4 further includes a DC switch control module, which is connected to the DC switch 6 and is used to disconnect the DC switch 6 when excessive current is detected to protect the electrical equipment under test. The above setting can effectively prevent the electrical equipment under test from being damaged or short-circuited when the current is excessive, improve the safety of the equipment, reduce the maintenance cost, extend the service life of the equipment, and thus improve the working efficiency of the equipment.

[0077] In a preferred solution, the measurement and control device 4 further includes a temperature detection module, which is connected to the temperature measuring resistor 7 and is used to monitor the temperature of the cable body 3 in real time. The above setting can send out an alarm in time when abnormal conditions such as high temperature occur in the cable body 3, reminding the staff to deal with it in time, and avoiding damage to the cable body 3 and the entire circuit system due to the high temperature of the cable body 3, thereby improving the practicability of the cable.

[0078] In a preferred solution, the measurement and control device 4 further includes an alarm module, which issues an overheat warning and controls the DC switch 6 to disconnect when the temperature of the cable body 3 exceeds a preset threshold. The above setting can effectively and timely detect the overheat condition of the cable body 3 and automatically disconnect the DC switch 6, thereby protecting the cable body 3 from catching fire or being damaged due to overheat and improving the safety of the entire power cable line.

[0079] In summary, the utility model provides a cable system for accurately measuring the output current of a DC power supply, which solves the problems that the ammeter provided by the existing DC power supply 8 has low measurement accuracy, is difficult to calibrate and cannot be disassembled, and the cable performance in the DC line cannot be monitored; by connecting a low-resistance standard resistor in series in the cable and using an external high-precision voltmeter for measurement, not only the accuracy of the current measurement is ensured, but also the safety and flexibility of the system are improved; using a micro-ohm-level standard resistor as a current sampling element ensures that its influence on the circuit is minimized and will not affect the normal flow of current, while providing high-precision current measurement; by connecting a high-precision voltmeter externally through the reserved voltage measurement terminal 2, the voltmeter can be replaced or calibrated at any time to ensure the accuracy of the measurement result, which is particularly suitable for scenarios that require regular calibration or work under different accuracy requirements; the voltmeter uses a high-precision voltmeter with a measurement accuracy of millivolts, and calibrates the high-precision voltmeter through an internal calibration circuit to ensure the accuracy of the measurement result, and is used to accurately measure the voltage across the standard resistor, thereby measuring the voltage according to the ohm value. The precise value of the output current of the DC power supply 8 is calculated by using Mu's law; the design integrates a measurement and control device 4, which can monitor the current waveform, temperature and other parameters in real time. Once an abnormality is found, such as too high current ripple coefficient or overheating of the cable, it can be fed back to the DC power supply 8 in time to adjust the output or directly disconnect the circuit, effectively preventing potential safety risks; the setting of each module in the measurement and control device 4 can accurately measure the precise value of the output current of the DC power supply 8, and display the current waveform in real time, which is conducive to analyzing the current waveform and ensuring the current quality; at the same time, by setting a temperature detection and alarm module, the temperature of the cable body 3 can be monitored in real time, and the power supply can be automatically disconnected when the temperature is too high to ensure the safety and reliability of the system; the utility model not only solves the problem of insufficient measurement accuracy of the existing DC power supply 8, but also improves the overall performance of the system through a series of innovative measures, improves the accuracy and convenience of current measurement in the overhaul and maintenance of power equipment, is of great significance for improving the current measurement accuracy and ensuring the stability and safety of circuit operation, and has high practical value and promotion potential in the field of electrical engineering.

[0080] In addition, the utility model is easy to operate and maintain. Users only need to perform simple operations according to the instructions to complete the measurement task, which reduces the difficulty of operation and maintenance costs. At the same time, the device has a compact structure and small size, is easy to carry and transport, and can be widely used in various power equipment inspection and maintenance sites.

Claims

1. A cable system for accurately measuring the output current of a DC power supply, characterized in that: It includes a cable body (3), on which a low-resistance standard resistor (1) is connected in series. The cable body (3) and the standard resistor (1) are insulated and connected by an insulating heat shrink sleeve. The standard resistor (1) and the conductor inside the cable are connected in parallel in a detachable manner through a quick-change joint. Voltage measurement terminals (2) are arranged at both ends of the standard resistor (1) for connecting to an external measurement and control device (4), and a high-precision voltmeter is arranged on the measurement and control device (4).

2. The cable system for accurately measuring the output current of a DC power supply according to claim 1, characterized in that: The resistance value range of the low-resistance standard resistor (1) is in the micro-ohm level to ensure that the over-current capacity of the cable is not affected when measuring the output current of the DC power supply (8).

3. A DC power supply output current precise measurement cable system according to claim 2, characterized in that: The measurement accuracy of the high-precision voltmeter is in the millivolt level, which is used to accurately measure the voltage across the standard resistor (1), so as to calculate the accurate value of the output current of the DC power supply (8) according to Ohm's law.

4. A direct current power supply output current precise measurement cable system according to claim 3, characterized in that: One end of the cable body (3) is connected to the output terminal of the DC power supply, and the other end is connected to the input terminal of the electrical equipment to be measured.

5. A DC power supply output current precise measurement cable system according to claim 4, characterized in that: The quick joint adopts a plug-in or threaded connection method to facilitate the replacement and calibration of the standard resistor (1).

6. A direct current power supply output current precise measurement cable system according to claim 5, characterized in that: A DC switch (6) and a temperature-measuring resistor (7) connected in series with the standard resistor (1) are also arranged on the cable body (3).

7. A DC power supply output current precise measurement cable system according to claim 6, characterized in that, The measurement and control device (4) further includes: An interface connected to an oscilloscope (5), and the oscilloscope (5) displays and analyzes the current waveform in real time; A current detection module for real-time detection of the current value in the cable body (3); A current control module, which is communicatively connected to the DC power supply and is used to send a feedback signal to the DC power supply to improve the waveform when the detected current ripple coefficient is too large.

8. A direct current power supply output current precise measurement cable system according to claim 7, characterized in that: The measurement and control device (4) further includes a DC switch control module, which is connected to the DC switch (6) and is used to disconnect the DC switch (6) when the detected current is too large to protect the electrical equipment to be measured.

9. A direct current power supply output current precise measurement cable system according to claim 8, characterized in that: The measurement and control device (4) further includes a temperature detection module, which is connected to the temperature-measuring resistor (7) and is used to monitor the temperature of the cable body (3) in real time.

10. A direct current power supply output current precise measurement cable system according to claim 9, characterized in that: The measurement and control device (4) further includes an alarm module, which issues an overheat warning and controls the DC switch (6) to disconnect when the temperature of the cable body (3) exceeds a preset threshold.

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