Detection circuit for short circuit of output loop of AC charging pile

Abstract

The utility model discloses an AC charging pile output loop short circuit detection circuit comprising an isolation power supply A and an isolation optocoupler B. The output end of the isolation power supply A is connected with the positive electrode of a diode D1, the negative electrode of the diode D1 is connected with one end of a resistor R1, and the other end of the resistor R1 is connected with a first pin of a relay J1 and one end of a resistor R2. A second pin of the relay J1 is connected with an output live wire L, a third pin of the relay J1 is connected with a signal K1, and the other end of the resistor R2 is connected with a first pin of the relay J2 and one end of the resistor R3; according to the utility model, the isolation power supply A and the isolation optocoupler B are adopted, and whether the output live wire and the output zero wire are short-circuited is determined through high-low level signals of the output voltage of the optocoupler B; when whether the output live wire L and the output zero wire N of the output loop are short-circuited or not is detected, the relays J1 and J2 are disconnected, the whole circuit cannot be connected to the energy transmission process, interference to a mainboard cannot be generated, and safety problems cannot be generated.

Description

Technical Field

[0001] This utility model relates to the technical field of detection circuits for AC charging piles, specifically a detection circuit for short circuits in the output circuit of an AC charging pile. Background Technology

[0002] With the increasing popularity of electric vehicles, AC charging stations, as an important charging facility, are of paramount importance in terms of safety and stability. During the use of AC charging stations, short circuit faults may occur in the output circuit. Short circuit faults can not only cause the charging station to malfunction, but may also lead to serious safety accidents such as fires.

[0003] The drawback of the existing solution is that the detection requires the use of a microcontroller's ADC sampling port. However, microcontroller resources are usually very limited, and sometimes the lack of an ADC sampling port necessitates the use of a more expensive chip, thus increasing costs. Utility Model Content

[0004] The purpose of this invention is to provide a detection circuit for short circuit in the output circuit of an AC charging pile, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a short-circuit detection circuit for the output circuit of an AC charging pile, comprising an isolation power supply A and an isolation optocoupler B. The output terminal of the isolation power supply A is connected to the positive terminal of diode D1, the negative terminal of diode D1 is connected to one end of resistor R1, the other end of resistor R1 is connected to pin 1 of relay J1 and one end of resistor R2, pin 2 of relay J1 is connected to the output live wire L, pin 3 of relay J1 is connected to signal K1, the other end of resistor R2 is connected to pin 1 of relay J2 and one end of resistor R3, pin 2 of relay J2 is connected to the output neutral wire N, pin 3 of relay J2 is connected to signal K2, pin 4 of relay J2 is connected to pin 4 of relay J1, the other end of resistor R3 is connected to the negative terminal of diode D2 and pin 1 of isolation optocoupler B, pin 2 of isolation optocoupler B is connected to one end of resistor R5, and pin 3 of isolation optocoupler B is connected to the positive terminal of diode D2 and one end of resistor R4.

[0006] Preferably, one end of the isolation power supply A is connected to the output U1.

[0007] Preferably, pin 4 of relay J2 and pin 4 of relay J1 are both connected to output U2.

[0008] Preferably, the other end of the resistor R5 is connected to the output U3.

[0009] Preferably, the other end of the resistor R4 is connected to the ground terminal CND2.

[0010] Preferably, pin four of the isolation optocoupler B is connected to the ground terminal CND1.

[0011] Preferably, pin 2 of the isolation optocoupler B and one end of resistor R5 are also connected to the output port OUT.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] This invention employs an isolated power supply A and an isolated optocoupler B. The high and low level signals of the output voltage of optocoupler B determine whether the output live wire and output neutral wire are short-circuited. Before energy transmission in the output circuit, signals K1 and K2 close relays J1 and J2, connecting the output live wire L and output neutral wire N to the detection circuit. When there is no short circuit between the output live wire L and output neutral wire N, the resistance between relays J1 and J2 is not short-circuited and participates in the voltage division of the entire circuit. When the resistance R2 between relays J1 and J2 is sufficiently large, the current on the input side of optocoupler B will be very small, insufficient to turn on the output side of optocoupler B, resulting in a high-level output from optocoupler B. Conversely, when there is a short circuit between the output live wire L and output neutral wire N, the resistance R2 between relays J1 and J2 is short-circuited, allowing a sufficiently large current to flow through optocoupler B, resulting in a low-level output from optocoupler B. When the output live wire L and the output neutral wire N of the output circuit are short-circuited, relays J1 and J2 are disconnected. The entire circuit will not be connected to the energy transmission process, will not interfere with the motherboard, and will not cause any safety issues. Attached Figure Description

[0014] Figure 1 This is the circuit diagram of this utility model. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0016] Please see Figure 1This utility model provides a short-circuit detection circuit for the output circuit of an AC charging pile, including an isolation power supply A and an isolation optocoupler B. The output terminal of the isolation power supply A is connected to the positive terminal of diode D1, the negative terminal of diode D1 is connected to one end of resistor R1, the other end of resistor R1 is connected to pin 1 of relay J1 and one end of resistor R2, pin 2 of relay J1 is connected to the output live wire L, pin 3 of relay J1 is connected to signal K1, the other end of resistor R2 is connected to pin 1 of relay J2 and one end of resistor R3, pin 2 of relay J2 is connected to the output neutral wire N, pin 3 of relay J2 is connected to signal K2, pin 4 of relay J2 is connected to pin 4 of relay J1, the other end of resistor R3 is connected to the negative terminal of diode D2 and pin 1 of isolation optocoupler B, pin 2 of isolation optocoupler B is connected to one end of resistor R5, and pin 3 of isolation optocoupler B is connected to the positive terminal of diode D2 and one end of resistor R4.

[0017] One end of the isolated power supply A is connected to output U1. Pin four of relay J2 and pin four of relay J1 are both connected to output U2. The other end of resistor R5 is connected to output U3. The other end of resistor R4 is connected to ground CND2. Pin four of the isolated optocoupler B is connected to ground CND1. Pin two of the isolated optocoupler B and one end of resistor R5 are also connected to the output port OUT.

[0018] In practical use: This output circuit short-circuit detection circuit employs an isolated power supply A and an isolated optocoupler B. The high or low level signal of the output voltage of optocoupler B determines whether the output live wire and output neutral wire are short-circuited. Before energy transmission in the output circuit, signals K1 and K2 close relays J1 and J2, connecting the output live wire L and output neutral wire N to the detection circuit. When there is no short circuit between the output live wire L and output neutral wire N, the resistance between relays J1 and J2 is not short-circuited and participates in the voltage division of the entire circuit. When the resistance R2 between relays J1 and J2 is sufficiently large, the current on the input side of optocoupler B will be very small, insufficient to turn on the output side of optocoupler B, resulting in a high-level output from optocoupler B. Conversely, when there is a short circuit between the output live wire L and output neutral wire N, the resistance R2 between relays J1 and J2 is short-circuited, allowing a sufficiently large current to flow through optocoupler B, resulting in a low-level output from optocoupler B. When the output live wire L and the output neutral wire N of the output circuit are short-circuited, relays J1 and J2 are disconnected. The entire circuit will not be connected to the energy transmission process, will not interfere with the motherboard, and will not cause any safety issues.

[0019] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A short-circuit detection circuit for the output circuit of an AC charging pile, comprising an isolation power supply A and an isolation optocoupler B, characterized in that: The output terminal of the isolation power supply A is connected to the positive terminal of diode D1. The negative terminal of diode D1 is connected to one end of resistor R1. The other end of resistor R1 is connected to pin 1 of relay J1 and one end of resistor R2. Pin 2 of relay J1 is connected to the output live wire L. Pin 3 of relay J1 is connected to signal K1. The other end of resistor R2 is connected to pin 1 of relay J2 and one end of resistor R3. Pin 2 of relay J2 is connected to the output neutral wire N. Pin 3 of relay J2 is connected to signal K2. Pin 4 of relay J2 is connected to pin 4 of relay J1. The other end of resistor R3 is connected to the negative terminal of diode D2 and pin 1 of isolation optocoupler B. Pin 2 of isolation optocoupler B is connected to one end of resistor R5. Pin 3 of isolation optocoupler B is connected to the positive terminal of diode D2 and one end of resistor R4.

2. The detection circuit for a short circuit in the output circuit of an AC charging pile according to claim 1, characterized in that: One end of the isolated power supply A is connected to the output U1.

3. The detection circuit for a short circuit in the output circuit of an AC charging pile according to claim 1, characterized in that: Pin 4 of relay J2 and pin 4 of relay J1 are both connected to output U2.

4. The detection circuit for a short circuit in the output circuit of an AC charging pile according to claim 1, characterized in that: The other end of the resistor R5 is connected to the output U3.

5. The detection circuit for a short circuit in the output circuit of an AC charging pile according to claim 1, characterized in that: The other end of the resistor R4 is connected to the ground terminal CND2.

6. The detection circuit for a short circuit in the output circuit of an AC charging pile according to claim 1, characterized in that: Pin four of the isolation optocoupler B is connected to the ground terminal CND1.

7. The detection circuit for a short circuit in the output circuit of an AC charging pile according to claim 1, characterized in that: Pin 2 of the isolation optocoupler B and one end of resistor R5 are also connected to the output port OUT.

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