CN211826211U - Residual current detection circuit for external circuit breaker of electric energy meter - Google Patents
Residual current detection circuit for external circuit breaker of electric energy meter Download PDFInfo
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- CN211826211U CN211826211U CN202020117314.0U CN202020117314U CN211826211U CN 211826211 U CN211826211 U CN 211826211U CN 202020117314 U CN202020117314 U CN 202020117314U CN 211826211 U CN211826211 U CN 211826211U
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- operational amplifier
- residual current
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- current detection
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Abstract
The utility model relates to a residual current detection circuitry for external circuit breaker of electric energy meter, it includes operational amplifier U5A, operational amplifier U5A's negative input end is connected with residual current sampling circuit's input, operational amplifier U5A's positive input end and reference voltage circuit connection, operational amplifier U5A's output and signal output circuit connection, reference voltage circuit and residual current sampling circuit are connected with two power input ends respectively, reference voltage circuit includes resistance R41 and resistance R42 that establish ties each other, wherein resistance R41's other end ground connection, resistance R42's another termination power supply, resistance R41 and resistance R42's junction is connected with operational amplifier U5A's positive input end, operational amplifier's negative input end is connected with sampling resistor R39, parallel resistance R44 between operational amplifier's output and the negative input end, the method is used for judging whether residual current exists or not and realizing accurate residual current detection.
Description
Technical Field
The utility model belongs to the low voltage apparatus field, concretely relates to residual current detection circuitry for electric energy meter external circuit breaker.
Background
The residual current is also called leakage current. The leakage current refers to the current formed between metal parts insulated from each other in the electric band or between a charged part and a grounded part through a medium or an insulating surface around the charged part in the absence of an applied voltage. That is, the sum of the current vectors of each phase (including neutral line) in the low-voltage distribution line and the current which is not zero, a very large current can be generated by the short circuit between the common phase and the interphase, the switch protection is adopted, the fire caused by the electric leakage caused by the electric shock of a human body and the aging of the line and the grounding fault of equipment are caused by the leakage current, generally 20mA-3A, the values are very small, and the tiny leakage current often becomes the hidden danger of the fire. The conventional switch cannot be protected and must be protected by a device for monitoring residual current.
SUMMERY OF THE UTILITY MODEL
Not enough to prior art exists, the utility model aims to provide a residual current detection circuitry for external circuit breaker of electric energy meter.
In order to achieve the above purpose, the utility model provides a following technical scheme:
a residual current detection circuit for an external circuit breaker of an electric energy meter comprises an operational amplifier U5A, the negative input terminal of the operational amplifier U5A is connected to the input terminal of the residual current sampling circuit, the positive input end of the operational amplifier U5A is connected with a reference voltage circuit, the output end of the operational amplifier U5A is connected with a signal output circuit, the reference voltage circuit and the residual current sampling circuit are respectively connected with two power supply input ends, the reference voltage circuit comprises a resistor R41 and a resistor R42 which are mutually connected in series, wherein the other end of the resistor R41 is grounded, the other end of the resistor R42 is connected with a power supply VDD, the connecting node of the resistor R41 and the resistor R42 is connected with the positive input end of the operational amplifier U5A, the negative input end of the operational amplifier is connected with the sampling resistor R39, and a resistor R44 is connected between the output end and the negative input end of the operational amplifier in parallel.
Two protection diodes which are arranged in opposite directions are connected in parallel between the positive input end and the negative input end of the operational amplifier.
And a resistor R40 is arranged between the negative input end of the operational amplifier and the sampling resistor R39.
The two power input ends are grounded through at least one capacitor respectively.
A capacitor C30 is connected in parallel between the two power supply input terminals.
The signal output circuit comprises a resistor R45 connected in series with the output terminal of the operational amplifier U5A and a capacitor C40 connected in parallel with the resistor R45.
The power supply VDD is grounded through several capacitors.
The utility model has the advantages that: by utilizing the operational amplifier and the reference voltage circuit, the induced voltage generated by the residual current detected by the residual current sampling circuit is raised according to the reference voltage to judge the waveform of the residual current, so that accurate residual current detection is realized.
Drawings
Fig. 1 is a schematic circuit diagram of the present invention.
Fig. 2 is a schematic circuit diagram of the power supply VDD according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
It should be noted that all the directional indicators (such as upper, lower, left, right, front and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.
In the present application, unless expressly stated or limited otherwise, the terms "connected" and "fixed" are to be construed broadly, e.g., "fixed" may be fixedly connected or detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
In addition, descriptions in the present application as to "first", "second", and the like are for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicit to the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions in the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should not be considered to exist, and is not within the protection scope of the present invention.
As shown in the figure, the utility model provides a residual current detection circuit for external circuit breaker of electric energy meter, it includes operational amplifier U5A, the negative input of operational amplifier U5A is connected with the input of residual current sampling circuit, the positive input of operational amplifier U5A is connected with reference voltage circuit, the output of operational amplifier U5A is connected with signal output circuit, reference voltage circuit and residual current sampling circuit are connected with two power input ends respectively, reference voltage circuit includes resistance R41 and resistance R42 that establish ties each other, provides reference voltage by these two resistances that establish ties, wherein the other end of resistance R41 is grounded, another termination power VDD of resistance R42, the junction of resistance R41 and resistance R42 is connected with the positive input of operational amplifier U5A, the negative input of operational amplifier U5A is connected with sampling resistance R39, when the residual current is generated, the parallel resistor R44 between the output end and the negative input end of the operational amplifier U5A generates a voltage waveform when flowing through the sampling resistor R39, and the voltage waveform is raised by the reference voltage to perform full-wave detection, so that the magnitude of the residual current is judged.
Two protection diodes which are oppositely arranged are connected in parallel between the positive input end and the negative input end of the operational amplifier, and the protection diodes D17 and D16 are used for preventing the residual current from being too high or the interference signal from being too large to damage the circuit.
A resistor R40 is arranged between the negative input end of the operational amplifier and the sampling resistor R39, and the resistor R40 and the resistor R44 form a peripheral circuit of the U5A of the operational amplifier.
The two power input ends are grounded through at least one capacitor respectively, and high-frequency filtering is performed by using the capacitors.
And a capacitor C30 is connected in parallel between the two power supply input ends and is used for high-frequency filtering.
The signal output circuit comprises a resistor R45 connected with the output end of the operational amplifier U5A in series and a capacitor C40 connected with the resistor R45 in parallel, wherein the resistor R45 plays a role of current limiting protection and prevents current surge from damaging a control chip receiving the signal.
The power supply VDD is grounded through a plurality of capacitors, and the power supply VDD is filtered through a capacitor C90, a capacitor C91, a capacitor C92, a capacitor C93 and a capacitor C84 which are connected in parallel.
The examples should not be construed as limiting the present invention, but any modifications made based on the spirit of the present invention should be within the scope of the present invention.
Claims (7)
1. The utility model provides a residual current detection circuit for external circuit breaker of electric energy meter which characterized in that: it includes operational amplifier U5A, operational amplifier U5A's negative input end is connected with residual current sampling circuit's input, operational amplifier U5A's positive input end and reference voltage circuit connection, operational amplifier U5A's output and signal output circuit are connected, reference voltage circuit and residual current sampling circuit are connected with two power input ends respectively, the reference voltage circuit includes resistance R41 and resistance R42 of establishing ties each other, and wherein resistance R41's the other end ground connection, resistance R42's another termination power VDD, resistance R41 and resistance R42's connecting node and operational amplifier U5A's positive input end are connected, operational amplifier's negative input end and sampling resistance R39 are connected, parallel resistance R44 between operational amplifier's the output and the negative input end.
2. The residual current detection circuit for the external circuit breaker of the electric energy meter according to claim 1, characterized in that: two protection diodes which are arranged in opposite directions are connected in parallel between the positive input end and the negative input end of the operational amplifier.
3. The residual current detection circuit for the external circuit breaker of the electric energy meter according to claim 1, characterized in that: and a resistor R40 is arranged between the negative input end of the operational amplifier and the sampling resistor R39.
4. The residual current detection circuit for the external circuit breaker of the electric energy meter according to claim 1, characterized in that: the two power input ends are grounded through at least one capacitor respectively.
5. The residual current detection circuit for the external circuit breaker of the electric energy meter according to claim 1, characterized in that: a capacitor C30 is connected in parallel between the two power supply input terminals.
6. The residual current detection circuit for the external circuit breaker of the electric energy meter according to claim 1, characterized in that: the signal output circuit comprises a resistor R45 connected in series with the output terminal of the operational amplifier U5A and a capacitor C40 connected in parallel with the resistor R45.
7. The residual current detection circuit for the external circuit breaker of the electric energy meter according to claim 1, characterized in that: the power supply VDD is grounded through several capacitors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020117314.0U CN211826211U (en) | 2020-01-19 | 2020-01-19 | Residual current detection circuit for external circuit breaker of electric energy meter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020117314.0U CN211826211U (en) | 2020-01-19 | 2020-01-19 | Residual current detection circuit for external circuit breaker of electric energy meter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211826211U true CN211826211U (en) | 2020-10-30 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020117314.0U Active CN211826211U (en) | 2020-01-19 | 2020-01-19 | Residual current detection circuit for external circuit breaker of electric energy meter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211826211U (en) |
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2020
- 2020-01-19 CN CN202020117314.0U patent/CN211826211U/en active Active
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