CN207964926U - A kind of residual current detection circuit - Google Patents
A kind of residual current detection circuit Download PDFInfo
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- CN207964926U CN207964926U CN201721370102.8U CN201721370102U CN207964926U CN 207964926 U CN207964926 U CN 207964926U CN 201721370102 U CN201721370102 U CN 201721370102U CN 207964926 U CN207964926 U CN 207964926U
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- resistance
- termination
- another termination
- operational amplifier
- mcu
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Abstract
The utility model proposes a kind of detection residual current detection circuit, the first magnetic beads（FB1）With the 5th resistance（R5）Operational amplifier is connected to after series connection（AR1）Positive input, the second magnetic bead（FB2）With the 6th resistance（R6）Series connection access operational amplifier（AR1）Reverse input end, the 8th resistance（R8）One the 6th resistance of termination（R6）And the 7th between resistance (R7), another termination microprocessor（MCU）Second analog input port（AN2）, second resistance（R2）One termination operational amplifier（AR1）Reverse input end, another termination operational amplifier（AR1）Output end, first resistor（R2）One termination operational amplifier（AR1）Output end, another termination microprocessor（MCU）First analog input port（AN1）, the first capacitance（C1）One termination microprocessor（MCU）First analog input port（AN1）, another termination power ground（GND）, first node（I1）With second node（I2）For residual current transformer input node.
Description
Technical field
The present invention relates to field of power electronics, are specifically related to a kind of residual current detection circuit.
Background technology
Residual current is also known as leakage current（Leakage current）.Refer to without voltage is applied, electrical middle band mutually insulated
Metal parts between, or with electrical accessory and ground connection part between, electric current is formed by by its surrounding medium or insulating surface
Referred to as leakage current.Each electric current phase (containing the neutral conductor) current phasor and be not zero, common namely in low-voltage distributing line
Short circuit occurs between phase and phase can generate very high current and use switch protection, and caused by occurring human electric shock, aging circuit
The earth fault for the fire and equipment that electricity leakage generates all is caused by leakage current, and general 20mA-3A, these values are very
It is small, and these small leakage currents usually become the hidden danger of fire.Traditional switch can not be protected and must be used to residue
Electric current is monitored and carries out the device of protection act to carry out.And monitoring device is often placed in strong electric field environment, be easy by
Interference causes detection inaccurate.
Invention content
For existing issue, the utility model proposes a kind of detection circuits of detection residual current.First magnetic bead（FB1）With
5th resistance（R5）Operational amplifier is connected to after series connection（AR1）Positive input, the second capacitance（C2）One end is connected to first
Magnetic bead（FB1）With the 5th resistance（R5）Between, another termination power ground（GND）, after 3rd resistor is in parallel with the 4th resistance one end
Connect operational amplifier（AR1）Positive input, another termination positive pole of 3rd resistor（VCC）, the other end of the 4th resistance
Connect power ground（GND）, the second magnetic bead（FB2）With the 6th resistance（R6）Series connection access operational amplifier（AR1）Reverse input end, the
Seven resistance（R7）One the 5th resistance of termination（R5）With the first magnetic bead（FB1）Between, the 6th resistance of another termination（R6）With the second magnetic
Pearl（FB2）Between, the 8th resistance（R8）One the 6th resistance of termination（R6）And the 7th between resistance (R7), another termination microprocessor
（MCU）Second analog input port（AN2）, third capacitance（C3）One the 6th resistance of termination（R6）With the 7th resistance (R7) it
Between, another termination power ground（GND）, triode（Q1）Collector connects the 6th resistance（R6）And the 7th between resistance (R7), base stage
Through the 9th resistance（R9）Connect microprocessor（MCU）First input/output port（I/O）, emitter is through the tenth resistance（R10）Connect electricity
Source, eleventh resistor（R11）One termination triode（Q1）Base stage, another termination power ground（GND）, second resistance（R2）One
Terminate operational amplifier（AR1）Reverse input end, another termination operational amplifier（AR1）Output end, first resistor（R2）One end
Connect operational amplifier（AR1）Output end, another termination microprocessor（MCU）First analog input port（AN1）, diode
（D1）One termination microprocessor（MCU）First analog input port（AN1）, another termination positive pole（VCC）, the first capacitance
（C1）One termination microprocessor（MCU）First analog input port（AN1）, another termination power ground（GND）, first node
（I1）With second node（I2）For residual current transformer input node.Wherein the 5th resistance（R5）Resistance value is zero ohms.Pass through
It whether there is leakage current in detection circuit, to whether there is the leakage current of fire hazard in decision circuitry.The detection circuit has
There are the short circuit of detection external residual current transformer, cut-out function, there is the characteristics of reliable and stable, strong antijamming capability.
Description of the drawings
Fig. 1 is circuit diagram
Specific implementation mode
As shown in Figure 1,3rd resistor（R3）With the 4th resistance（R4）After series connection, reference voltage is provided for operational amplifier.
5th resistance（R5）Play the role of anti-common mode interference.First magnetic bead（FB1）With the second magnetic bead（FB2）As inhibit high-frequency noise and
Spike interferes, and absorbs electrostatic pulse.First resistor（R1）Play current-limiting protection, prevents rush of current to microprocessor（MCU）
It damages, diode（D1）Play voltage-limiting protection, by microprocessor（MCU）The first analog input port（AN1）'s
Voltage clamp is in supply voltage（VCC）Below.
Microprocessor when normal detection（MCU）Control triode（Q1）It is in off state.
When there is no induced current in generation induced current in external residual current transformer, operational amplifier（AR1）'s
The voltage of output end output is equal with reference voltage.
When generating induced current in external residual current transformer, electric current flows through the 7th resistance（R7）, in the 7th resistance
（R7）Both ends generate voltage, by operational amplifier（AR1）Characteristic is it is found that in the 6th resistance（R6）On there is electric current to pass through, it is same big
Small electric current flows through second resistance（R2）, in operational amplifier（AR1）Output end output voltage, microprocessor at this time
（MCU）The first analog input port（AN1）Meeting detect a reference voltage and the 7th resistance（R7）Both end voltage passes through
The voltage being superimposed after amplification, according to this voltage combination reference voltage, proportion of utilization relationship can calculate in residual current transformer
The induced current of generation, and then leakage current present in decision circuitry.
Since external residual current transformer is there may be the situation of short circuit or open circuit, work as microprocessor（MCU）It detects
On the basis of induced voltage when voltage, triode is periodically opened（Q1）, by the 9th resistance（R9）And eleventh resistor（R11）Composition
Series loop be triode（Q1）Cut-in voltage is provided, triode is worked as（Q1）Opening is, in the 7th resistance（R7）With the tenth electricity
It hinders in the series loop constituted and generates electric current, microprocessor（MCU）Second analog input port（AN2）Through the 8th resistance（R8）
Collect node voltage value, residual current transformer itself there are certain resistance value, if external residual current transformer there may be
The situation of short circuit or open circuit, then first node（I1）Second node（I2）Between resistance be zero or be equal to the 7th resistance（R7）Resistance
Value, it is entirely different when this is normally accessed with residual current transformer, lead to microprocessor（MCU）Second analog input port
（AN2）The variation of node voltage value is collected, can judge feelings of the external residual current transformer with the presence or absence of short circuit or open circuit accordingly
Condition.
Second capacitance（C2）With third capacitance（C3）As High frequency filter.
Claims (2)
1. a kind of residual current detection circuit, it is characterized in that the first magnetic bead（FB1）With the 5th resistance（R5）Fortune is connected to after series connection
Calculate amplifier（AR1）Positive input, the second capacitance（C2）One end is connected to the first magnetic bead（FB1）With the 5th resistance（R5）It
Between, another termination power ground（GND）, 3rd resistor is in parallel with the 4th resistance one end to be followed by operational amplifier（AR1）Forward direction input
End, another termination positive pole of 3rd resistor（VCC）, another termination power ground of the 4th resistance（GND）, the second magnetic bead
（FB2）With the 6th resistance（R6）Series connection access operational amplifier（AR1）Reverse input end, the 7th resistance（R7）The 5th electricity of one termination
Resistance（R5）With the first magnetic bead（FB1）Between, the 6th resistance of another termination（R6）With the second magnetic bead（FB2）Between, the 8th resistance
（R8）One the 6th resistance of termination（R6）And the 7th between resistance (R7), another termination microprocessor（MCU）Second analog input
Port（AN2）, third capacitance（C3）One the 6th resistance of termination（R6）And the 7th between resistance (R7), another termination power ground
（GND）, triode（Q1）Collector connects the 6th resistance（R6）And the 7th between resistance (R7), base stage is through the 9th resistance（R9）It connects micro-
Processor（MCU）First input/output port（I/O）, emitter is through the tenth resistance（R10）Connect power ground, eleventh resistor
（R11）One termination triode（Q1）Base stage, another termination power ground（GND）, second resistance（R2）One termination operational amplifier
（AR1）Reverse input end, another termination operational amplifier（AR1）Output end, first resistor（R2）One termination operational amplifier
（AR1）Output end, another termination microprocessor（MCU）First analog input port（AN1）, diode（D1）The one micro- place of termination
Manage device（MCU）First analog input port（AN1）, another termination positive pole（VCC）, the first capacitance（C1）The one micro- place of termination
Manage device（MCU）First analog input port（AN1）, another termination power ground（GND）, first node（I1）With second node
（I2）For residual current transformer input node.
2. a kind of residual current detection circuit according to claim 1, it is characterized in that the 5th resistance（R5）Resistance value is zero Europe
Nurse.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721370102.8U CN207964926U (en) | 2017-10-24 | 2017-10-24 | A kind of residual current detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721370102.8U CN207964926U (en) | 2017-10-24 | 2017-10-24 | A kind of residual current detection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207964926U true CN207964926U (en) | 2018-10-12 |
Family
ID=63724465
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721370102.8U Expired - Fee Related CN207964926U (en) | 2017-10-24 | 2017-10-24 | A kind of residual current detection circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN207964926U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110007128A (en) * | 2019-05-07 | 2019-07-12 | 延锋伟世通电子科技（上海）有限公司 | A kind of low pressure low frequency small-signal current detection circuit |
| CN110780250A (en) * | 2019-09-30 | 2020-02-11 | 国创新能源汽车能源与信息创新中心(江苏)有限公司 | Automatic calibration system and method for residual current detection |
-
2017
- 2017-10-24 CN CN201721370102.8U patent/CN207964926U/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110007128A (en) * | 2019-05-07 | 2019-07-12 | 延锋伟世通电子科技（上海）有限公司 | A kind of low pressure low frequency small-signal current detection circuit |
| CN110007128B (en) * | 2019-05-07 | 2023-11-21 | 延锋伟世通电子科技（上海）有限公司 | Low-voltage low-frequency small-signal current detection circuit |
| CN110780250A (en) * | 2019-09-30 | 2020-02-11 | 国创新能源汽车能源与信息创新中心(江苏)有限公司 | Automatic calibration system and method for residual current detection |
| CN110780250B (en) * | 2019-09-30 | 2021-11-09 | 国创移动能源创新中心(江苏)有限公司 | Automatic calibration system and method for residual current detection |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20181012 Termination date: 20211024 |
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| CF01 | Termination of patent right due to non-payment of annual fee |