CN211014474U - Three-phase bias current detection circuit - Google Patents
Three-phase bias current detection circuit Download PDFInfo
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- CN211014474U CN211014474U CN201921735004.9U CN201921735004U CN211014474U CN 211014474 U CN211014474 U CN 211014474U CN 201921735004 U CN201921735004 U CN 201921735004U CN 211014474 U CN211014474 U CN 211014474U
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Abstract
The utility model belongs to the technical field of the detection circuitry technique and specifically relates to a three-phase bias current detection circuitry, three-phase sampling signal IU, IV, IW connect gradually resistance R1, resistance R2, connect the inverting terminal that U1A was put to fortune after resistance R3, put U1A in fortune and connect a resistance R4 back ground connection in the homophase end, the fortune is put and is inserted 15V voltage on U1A and supply power, put U1A's output at fortune and connect a feedback resistance R5 to inverting terminal; the output end of the operational amplifier U1A is connected to the in-phase end of the operational amplifier U1B, the output end of the operational amplifier U1B is connected to the inverting end of the operational amplifier U1B through a resistor R6, the output end of the operational amplifier U1B is output through a resistor R7, and the output end of the resistor R7 is connected to a +3.3V common ground auxiliary power supply through a resistor R8. The utility model provides a three-phase bias current detection circuitry handles the sum of three routes or multichannel electric current through addition operational amplifier, output control signal when taking place to leak current for three-phase or heterogeneous current detection need not extra zero sequence current sensor.
Description
Technical Field
The utility model belongs to the technical field of the detection circuitry technique and specifically relates to a three-phase bias current detection circuitry.
Background
In a three-phase power supply device and a three-phase power output device, for safety and/or for protecting related components, current balance detection needs to be performed on three phases so as to avoid faults caused by electric leakage or current bypass.
The common method is to use a zero sequence coil to perform common mode sampling, and then load the coupled current to a suitable resistor to obtain a bias current drop to trigger a corresponding protection circuit. However, the method cannot obtain the current value of each path, and cannot protect a certain path of overcurrent independently.
SUMMERY OF THE UTILITY MODEL
The utility model aims at solving the not enough of above-mentioned technique and providing a three-phase bias current detection circuitry, when producing the bias current in the three-phase sampling signal wantonly all the way, output voltage also can be skew.
In order to achieve the above object, the present invention provides a three-phase bias current detection circuit, in three-phase sampling signals IU, IV, IW of a three-phase power supply, wherein the three-phase sampling signals IU, IV, IW respectively correspond to a connection resistor R1, a resistor R2, a resistor R3, and the resistances of the resistor R1, the resistor R2, and the resistor R3 are the same, the other ends of the resistor R1, the resistor R2, and the resistor R3 are connected in parallel and then connected to the inverting terminal of the operational amplifier U1A, the inverting terminal of the operational amplifier U1A is connected to a resistor R4 and then grounded, the operational amplifier U1A is connected to ± 15V voltage for power supply, the output terminal of the operational amplifier U1A is connected to a feedback resistor R5 to the inverting terminal, and the resistance of the feedback resistor R5 is several times that of the resistor R1; the output end of the operational amplifier U1A is connected to the in-phase end of the operational amplifier U1B, the output end of the operational amplifier U1B is connected to the inverting end of the operational amplifier U1B through a resistor R6, the output end of the operational amplifier U1B is output through a resistor R7, and the output end of the resistor R7 is connected to a +3.3V common ground auxiliary power supply through a resistor R8; the resistance of the resistor R6, the resistance of the resistor R7 and the resistance of the resistor R8 are the same.
The resistance of the resistor R4 is 6.2K.
In the technical scheme, a general current transformer or a Hall is used for I-V conversion to obtain a sampling signal corresponding to a current value, when the sum of three inputs is 0 (three-phase current balance), the output pin 7 of an operational amplifier U1B is 0, and 1.65V direct current (3.3V partial pressure) is output after passing through R7 and R8; when any one of three-phase sampling values is larger or smaller, the output of the operational amplifier U1B deviates from 0V, the midpoint of R7 and R8 also deviates from 1.65V, and the deviation amplitude follows the bias current waveform; the output of the circuit is connected with a corresponding high-low level comparator, and three paths of input sum value deviations can be detected by setting a corresponding trigger value, so that bias current information is obtained.
The resistance of the feedback resistor R5 is 5 times the resistance of the resistor R1, and the sensitivity of bias current detection can be changed by changing the resistance of the feedback resistor R5 to be a multiple of the resistance of the resistor R1, wherein the higher the multiple is, the higher the sensitivity is.
The utility model provides a three-phase bias current detection circuitry handles the sum of three routes or multichannel electric current through addition operational amplifier, output control signal when taking place to leak current for three-phase or heterogeneous current detection need not extra zero sequence current sensor.
The leakage current of the three-phase current can be detected without a special zero-sequence sensor, and the detection sensitivity is adjustable; can be used for multi-path detection with more than 2 paths of input and with normal state and zero value.
Drawings
Fig. 1 is a circuit diagram of the present invention.
Detailed Description
The invention is further described by the following embodiments in conjunction with the accompanying drawings.
Example 1:
as shown in fig. 1, in the three-phase bias current detection circuit described in this embodiment, three-phase sampling signals IU, IV, and IW of a three-phase power supply are respectively and correspondingly connected to a resistor R1, a resistor R2, and a resistor R3, and resistances of the resistor R1, the resistor R2, and the resistor R3 are the same, and the other ends of the resistor R1, the resistor R2, and the resistor R3 are connected in parallel and then connected to an inverting terminal of an operational amplifier U1A, and the inverting terminal of the operational amplifier U1A is connected to a resistor R4 and then grounded, and a voltage of ± 15V is connected to the operational amplifier U1A for power supply, and an output terminal of the operational amplifier U1A is connected to a feedback resistor R5 to the inverting terminal, and a resistance of the feedback resistor R5 is five times that of the resistor R1; the output end of the operational amplifier U1A is connected to the in-phase end of the operational amplifier U1B, the output end of the operational amplifier U1B is connected to the inverting end of the operational amplifier U1B through a resistor R6, the output end of the operational amplifier U1B is output through a resistor R7, and the output end of the resistor R7 is connected to a +3.3V common ground auxiliary power supply through a resistor R8; the resistance of the resistor R6, the resistance of the resistor R7 and the resistance of the resistor R8 are the same. The resistance of the resistor R4 is 6.2K.
Claims (3)
1. A three-phase bias current detection circuit is characterized in that: three-phase sampling signals IU, IV and IW of a three-phase power supply are respectively and correspondingly connected with a resistor R1, a resistor R2 and a resistor R3, the resistances of the resistor R1, the resistor R2 and the resistor R3 are the same, the other ends of the resistor R1, the resistor R2 and the resistor R3 are connected in parallel and then connected to the inverting end of an operational amplifier U1A, the non-inverting end of the operational amplifier U1A is connected with a resistor R4 and then grounded, a voltage of +/-15V is connected to the operational amplifier U1A for power supply, the output end of the operational amplifier U1A is connected with a feedback resistor R5 to the inverting end, and the resistance of the feedback resistor R5 is several times that of the resistor R1; the output end of the operational amplifier U1A is connected to the in-phase end of the operational amplifier U1B, the output end of the operational amplifier U1B is connected to the inverting end of the operational amplifier U1B through a resistor R6, the output end of the operational amplifier U1B is output through a resistor R7, and the output end of the resistor R7 is connected to a +3.3V common ground auxiliary power supply through a resistor R8; the resistance of the resistor R6, the resistance of the resistor R7 and the resistance of the resistor R8 are the same.
2. The three-phase bias current detection circuit of claim 1, wherein: the resistance of the resistor R4 is 6.2K.
3. The three-phase bias current detection circuit of claim 1, wherein: the resistance of the feedback resistor R5 is 5 times that of the resistor R1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921735004.9U CN211014474U (en) | 2019-10-16 | 2019-10-16 | Three-phase bias current detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921735004.9U CN211014474U (en) | 2019-10-16 | 2019-10-16 | Three-phase bias current detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211014474U true CN211014474U (en) | 2020-07-14 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921735004.9U Expired - Fee Related CN211014474U (en) | 2019-10-16 | 2019-10-16 | Three-phase bias current detection circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN211014474U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112162217A (en) * | 2020-10-29 | 2021-01-01 | 安徽广识电气有限公司 | System for detecting leakage current of outgoing line of high-voltage switch cabinet |
-
2019
- 2019-10-16 CN CN201921735004.9U patent/CN211014474U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112162217A (en) * | 2020-10-29 | 2021-01-01 | 安徽广识电气有限公司 | System for detecting leakage current of outgoing line of high-voltage switch cabinet |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20200714 |
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| CF01 | Termination of patent right due to non-payment of annual fee |