PE detection circuit of AC charging pile

Abstract

The utility model relates to a PE detection circuit of an AC charging pile, and relates to the technical field of AC charging pile circuit design. The device comprises an operational amplifier module and an isolation module, a neutral line interface ACN is electrically connected to a first input end of the operational amplifier module, a protection ground line interface PE is electrically connected to a second input end of the operational amplifier module, and the operational amplifier module is used for detecting a voltage difference value between the neutral line interface ACN and the protection ground line interface PE; the output end of the operational amplifier module is output to the controller through the isolation module. The device has the effect of realizing the PE detection function of the AC charging pile.

Description

Technical Field

[0001] This application relates to the technical field of AC charging pile circuit design, and in particular to a PE detection circuit for an AC charging pile. Background Technology

[0002] AC charging piles have been prone to fires due to their high charging current, leading to increasingly stringent requirements for them. Therefore, the new national standard mandates that charging piles include a PE (protective earth) detection function. PE detection helps ensure the stable operation of charging equipment and improves charging efficiency and quality.

[0003] Under normal circumstances, the N (neutral) line and the PE (protective earth) line should have the same voltage. The N line is directly connected to the zero potential point of the transformer, while the PE line is connected to the ground through a different path. If, for some reason, the voltage difference between the PE and N lines exceeds 30V, then users of the charging station may be at risk of electric shock. Therefore, by detecting the voltage between the PE and N lines, we can detect problems in time and protect the safety of users. Utility Model Content

[0004] In order to realize the PE detection function of AC charging piles, this application provides a PE detection circuit for AC charging piles.

[0005] The PE detection circuit for an AC charging pile provided in this application adopts the following technical solution:

[0006] A PE detection circuit for an AC charging pile includes an operational amplifier module and an isolation module. The neutral line interface ACN is electrically connected to the first input terminal of the operational amplifier module, and the protective ground interface PE is electrically connected to the second input terminal of the operational amplifier module. The operational amplifier module is used to measure the voltage difference between the neutral line interface ACN and the protective ground interface PE. The output terminal of the operational amplifier module is output to the controller through the isolation module.

[0007] By adopting the above technical solution, the operational amplifier module can detect the voltage difference between the neutral line interface (ACN) and the protective ground interface (PE), thereby determining the current grounding status of the AC charging pile. Simultaneously, the isolation module provides electrical isolation, protecting the controller from potential electrical interference or voltage surges, and also improving system safety.

[0008] Preferably, the operational amplifier module includes an operational amplifier U1, the neutral line interface ACN is electrically connected to the non-inverting input terminal of the operational amplifier U1, the protective ground interface PE is electrically connected to the inverting input terminal of the operational amplifier U1, the output terminal of the operational amplifier U1 is electrically connected to the inverting input terminal of the operational amplifier U1 through a resistor R8, and the output terminal of the operational amplifier U1 is set as the output terminal of the operational amplifier module.

[0009] By adopting the above technical solution, the operational amplifier U1 can be used to detect the voltage difference between the neutral line interface ACN and the protective ground interface PE, so as to effectively monitor the safety status of the charging pile.

[0010] Preferably, the operational amplifier module further includes a capacitor C3, and the output terminal of the operational amplifier U1 is also electrically connected to the inverting input terminal of the operational amplifier U1 through the capacitor C3.

[0011] By adopting the above technical solution, capacitor C3 can improve the stability and anti-interference capability of the circuit.

[0012] Preferably, the operational amplifier module further includes a capacitor C1, and the non-inverting input terminal of the operational amplifier U1 is grounded through the capacitor C1.

[0013] By adopting the above technical solution, capacitor C1 plays the role of filtering and voltage regulation, which can improve the output stability of the neutral line port ACN.

[0014] Preferably, the isolation module further includes an amplification submodule and an optocoupler U3. The output terminal of the operational amplifier module is electrically connected to pin 1 of the optocoupler U3 through the amplification submodule, and pins 2 and 3 of the optocoupler U3 are grounded. The isolation module also includes a power supply V2. The voltage output terminal of the power supply V2 is electrically connected to the controller through a resistor R12. Pin 4 of the optocoupler U3 is set as the output terminal of the isolation module and is electrically connected to the controller.

[0015] By adopting the above technical solution, the output voltage of the operational amplifier module can be amplified by setting an amplification submodule to ensure that it is sufficient to drive the optocoupler U3. When the optocoupler U3 is off, the output voltage of the power supply V2 is output to the input terminal of the controller through the resistor R2, and the controller can receive a high-level signal at this time; when the optocoupler U3 is on, the input terminal of the controller is grounded through the optocoupler U3, that is, the controller can receive a level signal at this time.

[0016] Preferably, the amplification submodule includes an operational amplifier U2. The output terminal of the operational amplifier module is electrically connected to the non-inverting input terminal of the operational amplifier U2. The output terminal of the operational amplifier U2 is grounded through resistors R9 and R10 in sequence, and the connection point between resistors R9 and R10 is electrically connected to the inverting input terminal of the operational amplifier U2. The output terminal of the operational amplifier U2 is set as the output terminal of the amplification submodule.

[0017] By adopting the above technical solution and setting up the operational amplifier U2 and peripheral components, the output voltage of the operational amplifier module can be amplified.

[0018] In summary, this application includes at least one of the following beneficial technical effects:

[0019] The voltage difference between the neutral line interface (ACN) and the protective ground interface (PE) is measured using an operational amplifier module. Subsequently, an amplification submodule amplifies the output voltage of this operational amplifier module to ensure sufficient signal strength to drive the optocoupler U3. When the optocoupler U3 receives a sufficient signal to conduct, allowing the controller to receive a low-level signal, it indicates a potential problem with the protective ground connection of the AC charging pile.

[0020] In addition, the optocoupler U3 provides electrical isolation between the front-end detection circuit and the back-end controller, which effectively avoids mutual interference between the two, thereby enhancing the stability and safety of the entire system. Attached Figure Description

[0021] Figure 1 This is a schematic block diagram of an embodiment of this application;

[0022] Figure 2 This is a circuit diagram of the operational amplifier module in an embodiment of this application;

[0023] Figure 3 This is a circuit diagram of the isolation module in an embodiment of this application.

[0024] Figure labels: 1. Operational amplifier module; 2. Isolation module; 21. Amplification submodule. Detailed Implementation

[0025] The following is in conjunction with the appendix Figure 1-3 This application will be described in further detail.

[0026] This application discloses a PE detection circuit for an AC charging pile.

[0027] Reference Figure 1 A PE detection circuit for an AC charging pile includes an operational amplifier module 1 and an isolation module 2. The neutral line interface (ACN) of the AC charging pile is electrically connected to the first input terminal of the operational amplifier module 1, and the protective ground interface (PE) of the AC charging pile is electrically connected to the second input terminal of the operational amplifier module 1. The operational amplifier module 1 is used to detect the voltage difference between the neutral line interface (ACN) and the protective ground interface (PE), thereby determining whether the contact of the protective ground interface (PE) is normal or poor. The output terminal of the operational amplifier module 1 is output to the controller through the isolation module 2. The isolation module 2 provides isolation, enabling electrical isolation between the front-end detection circuit and the back-end controller, thus providing overall protection.

[0028] Reference Figure 2Operational amplifier module 1 includes operational amplifier U1. The neutral line interface ACN is electrically connected to the non-inverting input terminal of operational amplifier U1 via resistors R1, R2, and R3. The non-inverting input terminal of operational amplifier U1 is also grounded via resistor R7. The protective ground interface PE is electrically connected to the inverting input terminal of operational amplifier U1 via resistors R4, R5, and R6. The output terminal of operational amplifier U1 is electrically connected to the inverting input terminal of operational amplifier U1 via resistor R8, and the output terminal of operational amplifier U1 is set as the output terminal of operational amplifier module 1.

[0029] Preferably, the operational amplifier module 1 further includes capacitors C1 and C4. One end of capacitor C1 is electrically connected to the non-inverting input terminal of operational amplifier U1, and the other end of capacitor C1 is grounded. Capacitor C1 serves as a filter to ensure the stability of the neutral line interface ACN output voltage. One end of capacitor C4 is electrically connected to the inverting input terminal of operational amplifier U1, and the other end of capacitor C4 is electrically connected to the output terminal of operational amplifier U1. Capacitor C4 serves as a frequency compensation to compensate for the response delay caused by the input capacitance and suppress operational amplifier self-oscillation. This configuration helps ensure the stability of operational amplifier module 1.

[0030] This application embodiment also includes a positive power supply +V1 and a negative power supply -V1. The voltage output terminal of the positive power supply +V1 is electrically connected to the power supply terminal of the operational amplifier U1, and the voltage output terminal of the negative power supply -V1 is electrically connected to the ground terminal of the operational amplifier U1. Furthermore, the voltage output terminal of the positive power supply +V1 is also grounded through capacitor C2, with capacitor C1 acting as a filter to ensure the stability of the voltage output of the positive power supply +V1. The voltage output terminal of the negative power supply -V1 is also grounded through capacitor C3, with capacitor C3 acting as a filter to ensure the stability of the voltage output of the negative power supply -V1.

[0031] refer to Figure 3 The isolation module 2 includes an amplification submodule 21 and an optocoupler U3. The output terminal of the operational amplifier module 1 is electrically connected to the input terminal of the amplification submodule 21, and the output terminal of the amplification submodule 21 is electrically connected to the input terminal of the optocoupler U3. The amplification submodule 21 is used to amplify the output voltage of the operational amplifier module 1, thereby ensuring that the optocoupler U3 can operate normally.

[0032] The amplification submodule 21 includes an operational amplifier U2. The output terminal of the operational amplifier module 1 is electrically connected to the non-inverting input terminal of the operational amplifier U2. The output terminal of the operational amplifier U2 is grounded through resistors R9 and R10 in sequence. The connection point between resistors R9 and R10 is electrically connected to the inverting input terminal of the operational amplifier U2, and the output terminal of the operational amplifier U2 is set as the output terminal of the amplification submodule 21.

[0033] The output of amplification submodule 21 is electrically connected to pin 1 of optocoupler U3 via resistor R11, and pin 2 of optocoupler U3 is grounded. Isolation module 2 also includes power supply V2, the voltage output of which is electrically connected to pin 4 of optocoupler U3 via resistor R12, and pin 3 of optocoupler U3 is grounded. Pin 4 of optocoupler U3 is configured as the output of isolation module 2 and is also electrically connected to the input of the controller.

[0034] When the PE grounding port has poor contact, the voltage difference between the neutral line interface ACN and the protective ground interface PE is large. This allows the output voltage of operational amplifier module 1 to be amplified by amplification submodule 21, enabling optocoupler U3 to conduct. At this time, the voltage output of power supply V2 is grounded sequentially through resistor R12 and optocoupler U3, and isolation module 2 outputs a low-level signal. When the controller input receives this low-level signal, it can determine that the protective ground interface PE is poorly grounded and disconnect the charging process, alerting the user to the grounding problem. Conversely, if the output voltage of operational amplifier module 1 cannot turn on optocoupler U3 after amplification by amplification submodule 21, the voltage output of power supply V2 is output to the controller input sequentially through resistor R12, meaning isolation module 2 outputs a high-level signal. When the controller input receives this high-level signal, it can determine that the protective ground interface PE is properly grounded.

[0035] The implementation principle of the PE detection circuit for an AC charging pile according to this application embodiment is as follows: The operational amplifier module 1 detects the voltage difference between the neutral line interface (ACN) and the protective ground interface (PE). Then, the output voltage of the operational amplifier module 1 is amplified by the amplification submodule 21 to ensure that the optocoupler U3 can function normally. When the optocoupler U3 is conducting, i.e., when the controller receives a low-level signal, it is determined that the protective ground connection of the AC charging pile is faulty. Simultaneously, the optocoupler U3 enables electrical isolation between the front-end detection circuit and the back-end controller, effectively preventing mutual interference between the detection circuit and the main control system, and improving the stability and safety of the system.

[0036] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A PE detection circuit for an AC charging pile, characterized in that: The system includes an operational amplifier module (1) and an isolation module (2). The neutral line interface ACN is electrically connected to the first input terminal of the operational amplifier module (1), and the protective ground interface PE is electrically connected to the second input terminal of the operational amplifier module (1). The operational amplifier module (1) is used to measure the voltage difference between the neutral line interface ACN and the protective ground interface PE. The output terminal of the operational amplifier module (1) is output to the controller through the isolation module (2).

2. The PE detection circuit for an AC charging pile according to claim 1, characterized in that: The operational amplifier module (1) includes an operational amplifier U1. The neutral line interface ACN is electrically connected to the non-inverting input terminal of the operational amplifier U1, the protective ground interface PE is electrically connected to the inverting input terminal of the operational amplifier U1, and the output terminal of the operational amplifier U1 is electrically connected to the inverting input terminal of the operational amplifier U1 through a resistor R8. The output terminal of the operational amplifier U1 is set as the output terminal of the operational amplifier module (1).

3. The PE detection circuit for an AC charging pile according to claim 2, characterized in that: The operational amplifier module (1) also includes a capacitor C3, and the output terminal of the operational amplifier U1 is also electrically connected to the inverting input terminal of the operational amplifier U1 through the capacitor C3.

4. The PE detection circuit for an AC charging pile according to claim 3, characterized in that: The operational amplifier module (1) also includes a capacitor C1, and the non-inverting input terminal of the operational amplifier U1 is grounded through the capacitor C1.

5. The PE detection circuit for an AC charging pile according to claim 1, characterized in that: The isolation module (2) further includes an amplification submodule (21) and an optocoupler U3. The output terminal of the operational amplifier module (1) is electrically connected to pin 1 of the optocoupler U3 through the amplification submodule (21), and pins 2 and 3 of the optocoupler U3 are grounded. The isolation module (2) further includes a power supply V2. The voltage output terminal of the power supply V2 is electrically connected to the controller through a resistor R12. Pin 4 of the optocoupler U3 is set as the output terminal of the isolation module (2), and pin 4 of the optocoupler U3 is electrically connected to the controller.

6. The PE detection circuit for an AC charging pile according to claim 5, characterized in that: The amplification submodule (21) includes an operational amplifier U2. The output terminal of the operational amplifier module (1) is electrically connected to the non-inverting input terminal of the operational amplifier U2. The output terminal of the operational amplifier U2 is grounded in sequence through resistors R9 and R10. The connection point between resistors R9 and R10 is electrically connected to the inverting input terminal of the operational amplifier U2. The output terminal of the operational amplifier U2 is set as the output terminal of the amplification submodule (21).

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