Current detection system and detection circuit

Abstract

The utility model discloses a current detection system and a detection circuit, the current detection system comprises a first connecting line, a second connecting line, a feedback board, a connecting piece and a current detection device, the cross sectional area of the first connecting line is larger than that of the second connecting line, the first connecting line and the second connecting line are arranged in parallel, and the feedback board is connected with the connecting piece. One end of the first connecting line and one end of the second connecting line are respectively connected with the connecting piece, and the connecting piece is used for realizing the connection between the first connecting line and the uninterruptible power supply as well as between the second connecting line and the uninterruptible power supply; the current detection device is connected with the input end of the feedback board, and the output end of the feedback board is used for being connected with a controller of the uninterruptible power supply; according to the current detection system disclosed by the invention, the two connecting lines are connected in parallel for shunting, and the current detection device is arranged on the second connecting line with a smaller cross sectional area, so that the size, the weight and the cost of the current detection device are greatly reduced, and the current detection of various different types of uninterruptible power supplies is facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of current detection, in particular to a current detection system and a detection circuit. Background Art

[0002] An uninterruptible power supply (UPS) is a device that can provide stable power supply. When the main power supply, such as the commercial power supply, is interrupted, it can immediately provide power for connected electronic devices, such as computers, servers, data communication devices, etc. A UPS power supply usually includes a battery pack, a rectifier, a charger, and an inverter, which can ensure that the device can operate normally for a period of time when the power is interrupted, so that users can safely save data and shut down the device properly.

[0003] Traditional UPS power supplies directly measure the AC current of the bus using AC current transformers and directly measure the DC current of the bus using Hall sensors. For an uninterruptible power supply with only one independent output circuit, three AC current transformers and two Hall sensors are required. For an uninterruptible power supply with a parallel redundant configuration, nine AC current transformers and three Hall sensors are required, resulting in a high purchase cost. Moreover, the sizes of the AC current transformers and Hall sensors used for bus measurement are generally from a few centimeters to more than a dozen centimeters, with a large volume and weight. When designing the UPS chassis structure, it is necessary to consider their installation and fixation, resulting in a high installation cost.

[0004] It can be seen that the existing technology still needs to be improved. Summary of the Utility Model

[0005] In view of the deficiencies of the above-mentioned existing technology, the purpose of the present utility model is to provide a current detection system, which has the advantages of small volume, light weight, and low cost.

[0006] In order to achieve the above purpose, the present utility model adopts the following technical solutions:

[0007] A current detection system includes a first connecting wire, a second connecting wire, a feedback board, a connecting member, and a current detection device. The cross-sectional area of the first connecting wire is larger than that of the second connecting wire. The first connecting wire and the second connecting wire are arranged in parallel, and one end of the first connecting wire and one end of the second connecting wire are respectively connected to the connecting member. The connecting member is used to realize the connection between the first connecting wire, the second connecting wire, and the uninterruptible power supply. The current detection device is connected to the input end of the feedback board, and the output end of the feedback board is used to connect to the controller of the uninterruptible power supply.

[0008] In the described current detection system, there are also multiple first fixing straps. The first fixing straps are disposed around the outer sides of the first connecting wire and the second connecting wire, and the multiple first fixing straps are used to fix multiple positions of the first connecting wire and the second connecting wire.

[0009] In the described current detection system, the first connecting wire includes multiple first cables, and the multiple first cables are arranged to form a first cable bundle; the second connecting wire includes multiple second cables, and the multiple second cables are arranged to form a second cable bundle; the cross-sectional area of the first cable bundle is larger than the cross-sectional area of the second cable bundle.

[0010] In the described current detection system, the connecting member includes a wire ear, and one end of the first connecting wire and one end of the second connecting wire are respectively connected to the wire ear.

[0011] In the described current detection system, the connecting member includes two wire ears and a fixing member. One end of the first connecting wire is connected to any one of the wire ears, and one end of the second connecting wire is connected to the other wire ear; the two wire ears are fixedly connected through the fixing member, and the two wire ears are stacked.

[0012] In the described current detection system, the connecting member includes a connecting plate. A first connecting hole and a second connecting hole are formed on the connecting plate. One end of the first connecting wire is connected to the first connecting hole, and one end of the second connecting wire is connected to the second connecting hole.

[0013] In the described current detection system, the length difference between the first connecting wire and the second connecting wire is within 20%.

[0014] In the described current detection system, both the first connecting wire and the second connecting wire are copper wires, and the cross-sectional area standard of the first connecting wire and the second connecting wire is 5A / mm 2 , and the cross-sectional area of the second connecting wire is 0.8mm 2 -1.2mm 2 .

[0015] The present utility model also correspondingly provides a current detection circuit. The current detection circuit is printed on any one of the above-mentioned feedback boards. The current detection circuit includes a signal conversion part and a filtering part. The input end of the signal conversion part is connected to the current detection device, the output end of the signal conversion part is connected to the input end of the filtering part, and the output end of the filtering part is used to connect to the ADC pin of the controller of the uninterruptible power supply.

[0016] In the described current detection circuit, the signal conversion part includes a first resistor R1, the filtering part includes a second resistor R2 and a first capacitor C1. Both ends of the first resistor R1 are respectively connected to the current detection device. One end of the first resistor R1 is connected to one end of the second resistor R2, and the other end of the first resistor R1 is connected to the other end of the first capacitor C1. The other end of the second resistor R2 and one end of the first capacitor C1 are respectively used to connect to the ADC pin of the controller of the uninterruptible power supply.

[0017] Beneficial effects:

[0018] The present invention provides a current detection system. By setting two connecting wires in parallel for shunting and arranging the current detection device on the second connecting wire with a smaller cross-sectional area, the volume, weight, and cost of the current detection device are greatly reduced, that is, the procurement cost and installation cost of the current detection solution are greatly reduced. Moreover, the current detection system disclosed in this application can be used for current detection of various different types of uninterruptible power supplies, having the advantage of high applicability. Description of the Drawings

[0019] Figure 1 It is the system structure diagram of the current detection system provided by the present invention;

[0020] Figure 2 It is the circuit schematic diagram of the current detection system provided by the present invention.

[0021] Main element symbol description: 1 - First connecting wire, 2 - Second connecting wire, 3 - Feedback board, 4 - Current detection device, 5 - First fixing band, 6 - Controller. Specific Embodiments

[0022] The present invention provides a current detection system and a detection circuit. To make the purpose, technical solution, and effects of the present invention clearer and more definite, the following further elaborates on the present invention with reference to the accompanying drawings and by way of examples.

[0023] In the description of the present invention, it should be understood that terms such as "installation" and "connection" should be understood in a broad sense. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] Please refer to Figure 1 and Figure 2, the present utility model provides a current detection system, including a first connection line 1, a second connection line 2, a feedback board 3, a connector, and a current detection device 4. The cross-sectional area of the first connection line 1 is larger than that of the second connection line 2. The first connection line 1 and the second connection line 2 are arranged in parallel, and one end of the first connection line 1 and one end of the second connection line 2 are respectively connected to the connector. The connector is used to connect the first connection line 1 and the second connection line 2 to an uninterruptible power supply. The current detection device 4 is connected to the input end of the feedback board 3, and the output end of the feedback board 3 is used to connect to the controller 6 of the uninterruptible power supply.

[0025] This application discloses a current detection system. By setting two connection lines in parallel for shunting and arranging the current detection device 4 on the second connection line 2 with a smaller cross-sectional area, the volume, weight, and cost of the current detection device 4 are greatly reduced, that is, the procurement cost and installation cost of the current detection solution are greatly reduced. Moreover, the current detection system disclosed in this application can be used for current detection of various different types of uninterruptible power supplies, having the advantage of high applicability.

[0026] In this embodiment, the first connection line 1 includes a first cable, and the second connection line 2 includes a second cable. The cross-sectional area of the first cable is larger than that of the second cable. The current detection device 4 can be an AC current transformer or a Hall sensor, that is, the current detection system disclosed in this application can be used for AC or DC current detection of an uninterruptible power supply, and its current detection principle is the same.

[0027] Specifically, since one end of the first connection line 1 and one end of the second connection line 2 are connected together through a connector, the voltages at both ends are the same. According to Ohm's law U = IR, we can obtain:

[0028] I 大 R 大 = I 小 R 小

[0029] The total current of the two connection lines is the sum of the shunt circuits of the two connection lines. Therefore, the calculation method of the total current is:

[0030] I 总 = I 小 (R 大 + R 小 ) / R 大 ;

[0031] Substituting the resistance law R = ρL / S into the above formula, where ρ is the resistivity, L is the length of the connection line, and S is the cross-sectional area of the connection line, we can obtain:

[0032] I 总 = I小 (ρ 大 *L 大 / S 大 +ρ 小 *L 小 / S 小 ) / ρ 大 *L 大 / S 大 ;

[0033] Assume that both the first connection line 1 and the second connection line 2 are made of the same metal, so the resistivity ρ is the same. Assume further that the lengths L of the first connection line 1 and the second connection line 2 are also the same, then

[0034] I 总 = I 小 (1 + S 大 / S 小 );

[0035] Since the cross-sectional area ratio "S 大 / S 小 " is a constant, as long as I 小 is measured, I 总 can be calculated.

[0036] Since the second connection line 2 bears a small part of the current, a small-sized current detection device 4 can be selected, greatly reducing the volume, weight and procurement cost of the current detection device 4.

[0037] In other embodiments, the first connection line 1 includes a plurality of first cables, and the plurality of first cables are arranged to form a first cable bundle; the second connection line 2 includes a plurality of second cables, and the plurality of second cables are arranged to form a second cable bundle; the cross-sectional area of the first cable bundle is larger than the cross-sectional area of the second cable bundle.

[0038] For example, assume that the required cross-sectional area of the first connection line 1 is 30 mm 2 , three first cables with a cross-sectional area of 10 mm 2 can be used to form the first connection line 1. Assume that the required cross-sectional area of the second connection line 2 is 1 mm 2 , two second cables with a cross-sectional area of 0.5 mm 2 can be used to form the second connection line 2.

[0039] Furthermore, please refer to Figure 1 , the current detection system further includes a plurality of first fixing bands 5, the first fixing bands 5 are arranged around the outer sides of the first connection line 1 and the second connection line 2, and the plurality of first fixing bands 5 are used to fix the first connection line 1 and the second connection line 2 at multiple positions.

[0040] In this embodiment, the first fixing band 5 is a cable tie, and the parallel arrangement between the first connecting wire 1 and the second connecting wire 2 is realized through the first fixing band 5; the first connecting wire 1 and the second connecting wire 2 are routed side by side, so that the two connecting wires are in the same temperature space to keep the resistivity of the two connecting wires consistent; further, routing side by side also facilitates the inspection of whether the lengths of the two connecting wires are the same. If the two connecting wires are routed separately, one wire is close to the heat source and the other is far from the heat source, the temperatures of the two connecting wires are inconsistent, and the resistivity is inconsistent, which will cause measurement errors.

[0041] In this embodiment, the connecting member includes a wire ear, and one end of the first connecting wire 1 and one end of the second connecting wire 2 are respectively connected to the wire ear.

[0042] In this embodiment, the wire ear is also called a terminal or a wire nose, which is a prior art; by connecting one end of the first connecting wire 1 and one end of the second connecting wire 2 with a wire ear, the wiring is simple and not easy to be connected wrongly.

[0043] In another embodiment, the connecting member includes two wire ears and a fixing member. One end of the first connecting wire 1 is connected to any one of the wire ears, and one end of the second connecting wire 2 is connected to the other wire ear; the two wire ears are fixedly connected through the fixing member, and the two wire ears are stacked.

[0044] In this embodiment, the fixing member is a screw. When there are two wire ears, stack the two wire ears and fix them with screws. It should be noted that the wire ears should be matched to avoid insufficient contact area between the wire ears and the screws, resulting in loose joints or heating problems.

[0045] In another embodiment, the connecting member includes a connecting plate, and a first connection hole and a second connection hole are formed on the connecting plate. One end of the first connecting wire 1 is connected to the first connection hole, and one end of the second connecting wire 2 is connected to the second connection hole.

[0046] In this embodiment, the connecting plate is a copper plate or an aluminum plate, and the first connection hole and the second connection hole are adjacent to each other to ensure that the first connecting wire 1 and the second connecting wire 2 are routed side by side.

[0047] Further, the length difference between the first connecting wire 1 and the second connecting wire 2 is within 20%.

[0048] For example, assume that the first connection line 1 is 1 meter long, then the second connection line 2 is controlled to be between 0.8 and 1.2 meters; if the first connection line 1 is long and the second connection line 2 is short, the current in the second connection line 2 will be greater than the rated value, and it may overheat or even burn out; if the first connection line 1 is short and the second connection line 2 is long, the current in the second connection line 2 will be too small, wasting the range of the AC current transformer or Hall sensor, and the measurement error will increase. Therefore, the above two situations need to be avoided.

[0049] Further, both the first connection line 1 and the second connection line 2 are copper wires, and the cross-sectional area standard of the first connection line 1 and the second connection line 2 is 5 A / mm 2 , and the cross-sectional area of the second connection line 2 is 0.8 mm 2 - 1.2 mm 2 .

[0050] In other embodiments, both the first connection line 1 and the second connection line 2 can be aluminum wires, and the cross-sectional area standard of the first connection line 1 and the second connection line 2 can be 3 A / mm 2 , and can be redesigned according to actual usage requirements.

[0051] Please refer to Figure 2 , the present utility model also correspondingly provides a current detection circuit, the current detection circuit is printed on any one of the feedback boards 3 described above, the current detection circuit includes a signal conversion part and a filtering part, the input end of the signal conversion part is connected to the current detection device 4, the output end of the signal conversion part is connected to the input end of the filtering part, and the output end of the filtering part is used to connect to the ADC pin of the controller 6 of the uninterruptible power supply.

[0052] In this embodiment, the current signal output by the current detection device 4 is first converted into a voltage signal by the signal conversion part, and then the high-frequency interference clutter from the outside is filtered by the filtering part. The filtering part is a low-pass filter, and the filtered signal is sent to the ADC pin of the controller 6 in the control circuit. The ADC converts the signal into a digital quantity, and then the controller 6 calculates the current of the second connection line 2, and calculates the total current of the two connection lines according to the cross-sectional area ratio of the two connection lines; the controller 6 is a DSP controller 6, which is a prior art.

[0053] Further, please refer to Figure 2, the signal conversion unit includes a first resistor R1, the filtering unit includes a second resistor R2 and a first capacitor C1. Two ends of the first resistor R1 are respectively connected to the current detection device. One end of the first resistor R1 is connected to one end of the second resistor R2, and the other end of the first resistor R1 is connected to the other end of the first capacitor C1. The other end of the second resistor R2 and one end of the first capacitor C1 are respectively used for connecting the ADC pin of the controller of the uninterruptible power supply.

[0054] It can be understood that for those of ordinary skill in the art, equivalent substitutions or changes can be made according to the technical solutions and the inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A current detection system, characterized in that: It includes a first connecting line, a second connecting line, a feedback board, a connecting piece and a current detection device, the cross-sectional area of ​​the first connecting line is larger than the cross-sectional area of ​​the second connecting line, the first connecting line and the second connecting line are arranged in parallel, and one end of the first connecting line and one end of the second connecting line are respectively connected to the connecting piece, and the connecting piece is used to realize the connection between the first connecting line and the second connecting line and the uninterruptible power supply; the current detection device is connected to the input end of the feedback board, and the output end of the feedback board is used to connect to the controller of the uninterruptible power supply.

2. A current detection system according to claim 1, characterized in that: It also includes a plurality of first fixing belts, which are arranged around the outside of the first connecting line and the second connecting line, and the plurality of first fixing belts are used to fix multiple positions of the first connecting line and the second connecting line.

3. A current detection system according to claim 1, characterized in that: The first connecting line includes a plurality of first cables, and the plurality of first cables are arranged to form a first cable bundle; the second connecting line includes a plurality of second cables, and the plurality of second cables are arranged to form a second cable bundle; A cross-sectional area of ​​the first cable bundle is greater than a cross-sectional area of ​​the second cable bundle.

4. A current detection system according to claim 1, characterized in that: The connecting member includes a wire ear, and one end of the first connecting wire and one end of the second connecting wire are respectively connected to the wire ear.

5. A current detection system according to claim 1, characterized in that: The connecting member includes two wire ears and a fixing member, one end of the first connecting wire is connected to any one of the wire ears, and one end of the second connecting wire is connected to the other wire ear; the two wire ears are fixedly connected by the fixing member, and the two wire ears are stacked.

6. A current detection system according to claim 1, characterized in that: The connecting member includes a connecting plate, a first connecting hole and a second connecting hole are formed on the connecting plate, one end of the first connecting line is connected to the first connecting hole, and one end of the second connecting line is connected to the second connecting hole.

7. A current detection system according to claim 1, characterized in that: The length difference between the first connecting line and the second connecting line is within 20%.

8. A current detection system according to claim 1, characterized in that: The first connecting wire and the second connecting wire are both copper wires, and the cross-sectional area standard of the first connecting wire and the second connecting wire is 5A / mm 2 , the cross-sectional area of ​​the second connecting line is 0.8mm 2 -1.2mm 2 .

9. A current detection circuit, characterized in that: The current detection circuit is printed on the feedback board as described in any one of claims 1-8, and the current detection circuit includes a signal conversion unit and a filtering unit, the input end of the signal conversion unit is connected to the current detection device, the output end of the signal conversion unit is connected to the input end of the filtering unit, and the output end of the filtering unit is used to connect to the ADC pin of the controller of the uninterruptible power supply.

10. A current detection circuit according to claim 9, characterized in that: The signal conversion unit includes a first resistor R1, the filtering unit includes a second resistor R2 and a first capacitor C1, both ends of the first resistor R1 are respectively connected to the current detection device, one end of the first resistor R1 is connected to one end of the second resistor R2, the other end of the first resistor R1 is connected to the other end of the first capacitor C1, and the other end of the second resistor R2 and one end of the first capacitor C1 are respectively used to connect to the ADC pin of the controller of the uninterruptible power supply.

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