CN216285476U - Voltage sudden change trigger circuit - Google Patents
Voltage sudden change trigger circuit Download PDFInfo
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- CN216285476U CN216285476U CN202122881265.5U CN202122881265U CN216285476U CN 216285476 U CN216285476 U CN 216285476U CN 202122881265 U CN202122881265 U CN 202122881265U CN 216285476 U CN216285476 U CN 216285476U
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Abstract
The utility model relates to a voltage sudden change trigger circuit. The circuit comprises a half-wave rectification circuit, a low-pass filter circuit, a differential circuit, an operational amplification circuit and a switch control circuit; the input end of the half-wave rectification circuit is connected with a non-neutral grounding end of the sampling resistor; the output end of the half-wave rectification circuit is connected with the input end of the low-pass filter circuit; the output end of the low-pass filter circuit is connected with the input end of the differential circuit; the output end of the differential circuit is connected with the input end of the operational amplifier circuit; the output end of the operational amplification circuit is connected with the input end of the switch control circuit; the output end of the switch control circuit is connected with an interrupt signal input pin of the MCU; the input end of the half-wave rectification circuit is used as the integral input end of the voltage sudden change trigger circuit; the output end of the switch control circuit is used as the integral output end of the voltage sudden change trigger circuit. The utility model can quickly and effectively judge the line state, thereby prolonging the service life of the fault sensor.
Description
Technical Field
The utility model relates to the technical field of electronic circuits, in particular to a voltage sudden change trigger circuit.
Background
In a ring network power distribution system, line faults occur frequently, and ground faults and short-circuit faults occur most frequently. Therefore, in the power system using the ring main unit load switch, in order to timely and comprehensively master various operation data and fault information of the power distribution network and quickly determine the fault section of the isolation line, fault sensors are required to be installed on cables in various ring main units. The fault sensor is limited by the volume of the ring main unit, and in order to deal with various complex environments, such as outdoor installation and use, long-time low-load operation of a power grid and the like, the fault sensor installed in the main unit can adopt a small-volume design, the inside is powered by a lithium battery, and the lithium battery is sealed by glue filling, and the capacity of the lithium battery often determines the service life of the fault sensor.
At present, on the premise of not influencing the reliability and the installation comfort of an internal circuit of a fault sensor, in order to prolong the service life of the fault sensor, the universal improvement scheme is that a fault awakening function is added for the internal circuit of the fault sensor, when the current in a circuit is lower than an awakening set value, the working state of an MCU of the internal circuit of the fault sensor can be alternately carried out between dormancy and timing sampling, and when the current in the circuit is higher than the awakening set value, the MCU starts real-time sampling after receiving an interrupt trigger signal. On the surface, the scheme can effectively reduce the power consumption of the internal circuit of the sensor, but actually, because the current in the line belongs to the alternating current which changes periodically, on the premise of not performing effective processing, the normal load current in the line can be misjudged as the fault current when reaching the awakening set value, so that the MCU continuously receives the interrupt trigger signal, the MCU enters the working state of real-time sampling for a long time, and the service life of the fault sensor is shortened.
In summary, a voltage jump trigger circuit is needed to solve the deficiencies of the prior art.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a voltage sudden change trigger circuit which can quickly and effectively judge the line state so as to prolong the service life of a fault sensor.
In order to achieve the purpose, the utility model provides the following scheme:
a voltage jump trigger circuit is used for a fault sensor; the internal circuit of the fault sensor is provided with a sampling resistor and an MCU; the voltage sudden change trigger circuit comprises: the circuit comprises a half-wave rectification circuit, a low-pass filter circuit, a differential circuit, an operational amplification circuit and a switch control circuit;
the input end of the half-wave rectifying circuit is connected with a non-neutral grounding end of the sampling resistor; the output end of the half-wave rectification circuit is connected with the input end of the low-pass filter circuit; the output end of the low-pass filter circuit is connected with the input end of the differential circuit; the output end of the differential circuit is connected with the input end of the operational amplification circuit; the output end of the operational amplification circuit is connected with the input end of the switch control circuit; the output end of the switch control circuit is connected with an interrupt signal input pin of the MCU;
the input end of the half-wave rectifying circuit is used as the integral input end of the voltage sudden change trigger circuit; and the output end of the switch control circuit is used as the integral output end of the voltage sudden change trigger circuit.
Optionally, the half-wave rectification circuit includes: and a diode.
Optionally, the diode is a low turn-on voltage schottky diode.
Optionally, the low-pass filter circuit includes: a first resistor and a first capacitor;
one end of the first resistor is connected with the output end of the half-wave rectification circuit; the other end of the first resistor is respectively connected with one end of the first capacitor and the input end of the differential circuit; the other end of the first capacitor is grounded.
Optionally, a cut-off frequency of the low-pass filter circuit is less than 50 Hz.
Optionally, the differentiating circuit comprises: a second capacitor and a second resistor;
one end of the second capacitor is connected with the output end of the low-pass filter circuit; the other end of the second capacitor is respectively connected with the input end of the operational amplification circuit and one end of the second resistor; the other end of the second resistor is grounded.
Optionally, the operational amplifier circuit includes an operational amplifier, a third resistor, a fourth resistor, and a fifth resistor;
the positive input end of the operational amplifier is connected with the third resistor; the negative input end of the operational amplifier is respectively connected with the fourth resistor and the fifth resistor; the other end of the third resistor is an input end of the operational amplification circuit; the other end of the fourth resistor is grounded; the other end of the fifth resistor is connected with the output end of the operational amplifier, and the connection point is the output end of the operational amplifier circuit.
Optionally, the model of the operational amplifier is RS8032 XM.
Optionally, the switch control circuit includes a transistor, a sixth resistor, a seventh resistor, and an eighth resistor;
the base electrode of the triode is respectively connected with the sixth resistor and the seventh resistor; the emitting electrode of the triode is grounded; the collector of the triode is connected with the eighth resistor, and the connection point is the output end of the switch control circuit; the other end of the sixth resistor is an input end of the switch control circuit; the other end of the seventh resistor is grounded; the other end of the eighth resistor is connected with a power supply.
Optionally, the model of the triode is S9014.
According to the specific embodiment provided by the utility model, the utility model discloses the following technical effects:
the utility model provides a voltage sudden change trigger circuit, wherein an internal circuit of a current sensor is provided with a sampling resistor and an MCU (microprogrammed control unit), and the voltage sudden change trigger circuit comprises a half-wave rectifying circuit, a low-pass filter circuit, a differential circuit, an operational amplification circuit and a switch control circuit which are sequentially connected. The input end of the half-wave rectifying circuit is connected with the sampling resistor; the output end of the switch control circuit is connected with the MCU chip. Through the low-pass filter circuit and the differential circuit, different signals can be generated according to the running state of the line and sent to the post-stage circuit, so that the phenomenon that the normal load current of the line is judged as the fault current by mistake is avoided. Through the operational amplification circuit, the signal amplification factor can be flexibly set, so that the controllability of a circuit sudden change current threshold is realized, and the MCU is prevented from being frequently awakened or not awakened. The voltage sudden change trigger circuit is simple and reasonable in structural design, convenient to implement and low in cost. By matching the cut-off frequency of the low-pass filter circuit, the line state can be accurately judged; by selecting the operational amplifier with high response speed, the real-time performance of detection can be ensured. Therefore, the utility model can strictly limit the power consumption of the fault sensor and prolong the service life of the fault sensor on the premise of not influencing the reliability of fault detection.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.
Fig. 1 is a schematic diagram of a voltage jump trigger circuit according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The utility model aims to provide a voltage sudden change trigger circuit which can quickly and effectively judge the line state so as to prolong the service life of a fault sensor.
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
As shown in fig. 1, a voltage sudden change trigger circuit for a current sensor includes a half-wave rectifier circuit 1, a low-pass filter circuit 2, a differentiating circuit 3, an operational amplifier circuit 4, and a switch control circuit 5, which are connected in sequence.
The half-wave rectification circuit 1 comprises a diode D1, the anode of a diode D1 is connected with the non-neutral grounding end of the current sensor sampling resistor R0, and the cathode of a diode D1 is connected with the low-pass filter circuit 2.
The low-pass filter circuit 2 comprises a first resistor R1 and a first capacitor C1, the connection point of the first resistor R1 and the first capacitor C1 is connected with the differential circuit 3, the other end of the first resistor R1 is connected with the half-wave rectification circuit 1, and the other end of the first capacitor C1 is connected with GND.
The differential circuit 3 comprises a second capacitor C2 and a second resistor R2, the connection point of the second capacitor C2 and the second resistor R2 is connected with the operational amplifier circuit 4, the other end of the second capacitor C2 is connected with the low-pass filter circuit 2, and the other end of the second resistor R2 is connected with GND.
The operational amplification circuit 4 comprises an operational amplifier U1, a third resistor R3, a fourth resistor R4 and a fifth resistor R5, the positive input end of the operational amplifier U1 is connected with the third resistor, the negative input end of the operational amplifier U1 is respectively connected with the fourth resistor and the fifth resistor, and the output end of the operational amplifier U1 is connected with the switch control circuit 5;
the switch control current 5 comprises a triode Q1, a sixth resistor R6, a seventh resistor R7 and an eighth resistor R8, the base of the triode Q1 is respectively connected with the sixth resistor R6 and the seventh resistor R7, the emitter of the triode Q1 is connected with GND, the collector of the triode Q1 is connected with the eighth resistor R8, the connection point is the output end of the switch control circuit 5, and the other end of the eighth resistor R8 is connected with VCC.
The voltage sudden change trigger circuit of the embodiment is realized according to the following principle: when the line normally runs, the voltage of V0 is 50Hz sine alternating current, which is half-wave rectified by diode D1 and sent to low-pass filter circuit 2, because of the cut-off frequency set by low-pass filter circuit 2
Less than 50Hz, the voltage V1 is DC signal after R1 and C1 integration, and the differentiating circuit 2 has the function of AC/DC resistance, so the differentiating process by C2 and R2Then, the output voltage is 0, the forward input of the operational amplifier U1 is 0, the output voltage of U1 cannot drive the transistor Q1 to be conducted, and the MCU interrupt command cannot be issued; when a line has a fault, the voltage of V0 can be rapidly increased, after the line is processed by the half-wave rectification circuit 1 and the low-pass filter circuit 2, the output voltage V1 can be rapidly increased to form a new direct-current signal, the voltage increasing process is marked as a fault characteristic signal, the fault characteristic signal can be converted into a pulse signal after being subjected to differential processing by C2 and R2, after the pulse signal is received by the forward input of the operational amplifier U1, the pulse signal is amplified according to the amplification factor determined by the resistor R4 and the resistor R5, when the amplified pulse signal is greater than the conduction voltage threshold of the triode Q1, the triode Q1 is conducted, and the MCU interrupt command is sent.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The principles and embodiments of the present invention have been described herein using specific examples, which are provided only to help understand the method and the core concept of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the utility model.
Claims (10)
1. A voltage jump trigger circuit is used for a fault sensor; the internal circuit of the fault sensor is provided with a sampling resistor and an MCU; the voltage sudden change trigger circuit is characterized by comprising: the circuit comprises a half-wave rectification circuit, a low-pass filter circuit, a differential circuit, an operational amplification circuit and a switch control circuit;
the input end of the half-wave rectifying circuit is connected with a non-neutral grounding end of the sampling resistor; the output end of the half-wave rectification circuit is connected with the input end of the low-pass filter circuit; the output end of the low-pass filter circuit is connected with the input end of the differential circuit; the output end of the differential circuit is connected with the input end of the operational amplification circuit; the output end of the operational amplification circuit is connected with the input end of the switch control circuit; the output end of the switch control circuit is connected with an interrupt signal input pin of the MCU;
the input end of the half-wave rectifying circuit is used as the integral input end of the voltage sudden change trigger circuit; and the output end of the switch control circuit is used as the integral output end of the voltage sudden change trigger circuit.
2. The voltage sudden change trigger circuit according to claim 1, wherein the half-wave rectifier circuit comprises: and a diode.
3. The voltage transition trigger circuit of claim 2, wherein the diode is a low turn-on voltage schottky diode.
4. The voltage sudden change trigger circuit according to claim 1, wherein the low-pass filter circuit comprises: a first resistor and a first capacitor;
one end of the first resistor is connected with the output end of the half-wave rectification circuit; the other end of the first resistor is respectively connected with one end of the first capacitor and the input end of the differential circuit; the other end of the first capacitor is grounded.
5. The voltage sudden change trigger circuit according to claim 1, wherein the cut-off frequency of the low-pass filter circuit is less than 50 Hz.
6. The voltage transition trigger circuit of claim 1, wherein the differentiating circuit comprises: a second capacitor and a second resistor;
one end of the second capacitor is connected with the output end of the low-pass filter circuit; the other end of the second capacitor is respectively connected with the input end of the operational amplification circuit and one end of the second resistor; the other end of the second resistor is grounded.
7. The voltage sudden change trigger circuit according to claim 1, wherein the operational amplifier circuit comprises an operational amplifier, a third resistor, a fourth resistor and a fifth resistor;
the positive input end of the operational amplifier is connected with the third resistor; the negative input end of the operational amplifier is respectively connected with the fourth resistor and the fifth resistor; the other end of the third resistor is an input end of the operational amplification circuit; the other end of the fourth resistor is grounded; the other end of the fifth resistor is connected with the output end of the operational amplifier, and the connection point is the output end of the operational amplifier circuit.
8. The voltage sudden change trigger circuit according to claim 7, wherein the operational amplifier is RS8032 XM.
9. The voltage sudden change trigger circuit according to claim 1, wherein the switch control circuit comprises a triode, a sixth resistor, a seventh resistor and an eighth resistor;
the base electrode of the triode is respectively connected with the sixth resistor and the seventh resistor; the emitting electrode of the triode is grounded; the collector of the triode is connected with the eighth resistor, and the connection point is the output end of the switch control circuit; the other end of the sixth resistor is an input end of the switch control circuit; the other end of the seventh resistor is grounded; the other end of the eighth resistor is connected with a power supply.
10. The voltage sudden change trigger circuit according to claim 9, wherein the type of the triode is S9014.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122881265.5U CN216285476U (en) | 2021-11-23 | 2021-11-23 | Voltage sudden change trigger circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202122881265.5U CN216285476U (en) | 2021-11-23 | 2021-11-23 | Voltage sudden change trigger circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN216285476U true CN216285476U (en) | 2022-04-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202122881265.5U Active CN216285476U (en) | 2021-11-23 | 2021-11-23 | Voltage sudden change trigger circuit |
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| Country | Link |
|---|---|
| CN (1) | CN216285476U (en) |
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2021
- 2021-11-23 CN CN202122881265.5U patent/CN216285476U/en active Active
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