Pre-charging system of charging pile

Abstract

The utility model provides a charging pile pre-charging system, and belongs to the technical field of charging piles. The charging pile pre-charging system comprises a central control module, a first driving module, a second driving module, a first relay, a second relay and a resistor, the charging detection module is used for detecting the connection state of the charging connector and the electric vehicle; the first end of the first driving module is connected with the central control module, the second end of the first driving module is connected with the control end of the first relay, the first end of the first relay is connected with the first end of the resistor, and the second end of the resistor is connected with a power grid; the first end of the second driving module is connected with the central control module, the second end of the second driving module is connected with the control end of the second relay, the first end of the second relay is connected with the second end of the resistor, and the second end of the second relay is connected with the second end of the first relay. The problem that the service life of the battery and user safety are affected can be solved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of charging piles, and particularly to a pre-charging system for a charging pile. Background Art

[0002] With the booming development of the new energy vehicle industry, the popularity rate of electric vehicles is increasing day by day, and the demand for efficient and safe charging facilities is also increasing. However, traditional charging methods often generate a large current impact at the moment of startup, posing a potential threat to the batteries and electrical systems of electric vehicles and affecting battery life and user safety. Summary of the Utility Model

[0003] Embodiments of the present disclosure provide a pre-charging system for a charging pile to solve the problems affecting battery life and user safety.

[0004] Embodiments of the present disclosure provide a pre-charging system for a charging pile, including:

[0005] A central control module, a charging detection module, a first driving module, a second driving module, a first relay, a second relay, and a resistor;

[0006] The charging detection module is connected to the central control module, and the charging detection module is used to detect the connection state between the charging connector and the electric vehicle;

[0007] The first end of the first driving module is connected to the central control module, the second end of the first driving module is connected to the control end of the first relay, the first end of the first relay is connected to the first end of the resistor, the second end of the resistor is used to connect to the power grid, and the second end of the first relay is used to output a charging voltage;

[0008] The first end of the second driving module is connected to the central control module, the second end of the second driving module is connected to the control end of the second relay, the first end of the second relay is connected to the second end of the resistor, and the second end of the second relay is connected to the second end of the first relay.

[0009] In an exemplary embodiment of the present disclosure, it further includes: a voltage sampling module;

[0010] The first end of the voltage sampling module is connected to the second end of the first relay, and the second end of the voltage sampling module is connected to the central control module.

[0011] In an exemplary embodiment of the present disclosure, the first relay includes: relay K1; the first driving module includes: triode Q2; the resistor includes: resistor RL;

[0012] The base of the triode Q2 is connected to the central control module, the collector of the triode Q2 is connected to the VCC power supply, the emitter of the triode Q2 is connected to the first control end of the relay K1, the second control end of the relay K1 is grounded, the first end of the relay K1 is connected to the first end of the resistor RL, the second end of the resistor RL is used to connect to the power grid, and the second end of the relay K1 is used to output the charging voltage.

[0013] In an exemplary embodiment of the present disclosure, the first driving module further includes: a controller U1 and a rheostat RP1;

[0014] The power supply terminal of the controller U1 is connected to the emitter of the triode Q2, the adjustment terminal of the controller U1 is connected to the sliding terminal of the rheostat RP1, the first end of the rheostat RP1 is connected to the emitter of the triode Q2, the second end of the rheostat RP1 is grounded, the first control end of the relay K1 is connected to the feedback terminal of the controller U1, the second control end of the relay K1 is connected to the input terminal of the controller U1, and the ground terminal of the controller U1 is grounded.

[0015] In an exemplary embodiment of the present disclosure, the charging detection module includes: a micro switch SW1 and an optocoupler U3;

[0016] The first end of the micro switch SW1 is connected to the VCC power supply, the second end of the micro switch SW1 is connected to the first input terminal of the optocoupler U3, the second input terminal of the optocoupler U3 is grounded, the first output terminal of the optocoupler U3 is connected to the VDD power supply, and the second output terminal of the optocoupler U3 is connected to the central control module.

[0017] In an exemplary embodiment of the present disclosure, the charging detection module further includes: a resistor R7, a capacitor C4, a triode Q1, a triode Q1, a capacitor C5, a resistor R10, a transistor Q3, and a light emitting diode LED1;

[0018] The first end of the resistor R7 is connected to the VCC power supply, the second end of the resistor R7 is grounded through the capacitor C4, the second end of the resistor R7 is connected to the base of the triode Q1, the collector of the triode Q1 is connected to the second end of the micro switch SW1, the emitter of the triode Q1 is grounded through the capacitor C5, the emitter of the triode Q1 is connected to the control end of the transistor Q1, the first end of the resistor R10 is connected to the second end of the micro switch SW1, the second end of the resistor R10 is connected to the first end of the transistor Q3, the second end of the transistor Q3 is connected to the anode of the light emitting diode LED1, and the cathode of the light emitting diode LED1 is grounded.

[0019] In an exemplary embodiment of the present disclosure, the voltage sampling module includes: diode D2, resistor R3, resistor R4, operational amplifier U2, resistor R6, and resistor R5;

[0020] The anode of the diode D2 is connected to the second terminal of the first relay, the cathode of the diode D2 is connected to the first terminal of the resistor R3, the second terminal of the resistor R3 is grounded through the resistor R4, the second terminal of the resistor R3 is connected to the non-inverting input terminal of the operational amplifier U2, the inverting input terminal of the operational amplifier U2 is grounded through the resistor R6, the output terminal of the operational amplifier U2 is connected to the inverting input terminal of the operational amplifier U2 through the resistor R5, and the output terminal of the operational amplifier U2 is connected to the central control module.

[0021] The beneficial effects of a pre-charging system for a charging pile provided by an embodiment of the present disclosure are as follows: The embodiment of the present disclosure can instantly detect the connection state between the charging gun head and the electric vehicle interface, ensuring the accurate start of the charging operation. During the pre-charging stage, the introduction of the resistor effectively limits the initial charging current, avoiding the impact of instantaneous large current on the electric vehicle battery and protecting the battery life and the safety of the vehicle's electrical system. As the charging enters the stable stage, the embodiment of the present disclosure automatically switches to the second relay path, bypassing the current-limiting resistor and directly providing a higher-efficiency charging current, thereby greatly shortening the charging time and improving the user experience. This not only reflects the comprehensive consideration of the charging safety of electric vehicles but also demonstrates the improvement in charging efficiency. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 is a structural block diagram of a pre-charging system for a charging pile provided by an embodiment of the present disclosure;

[0024] Figure 2 is a circuit diagram of a pre-charging system for a charging pile provided by an embodiment of the present disclosure;

[0025] Figure 3 is a circuit diagram of a charging detection module provided by an embodiment of the present disclosure. Detailed Embodiments

[0026] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below in conjunction with the accompanying drawings in the embodiments of this solution. Obviously, the described embodiments are some, but not all, of the embodiments of this solution. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this solution without making creative efforts shall fall within the scope of protection of this solution.

[0027] The terms "including" and any other variations in the specification, claims, and above-mentioned accompanying drawings of this solution mean "including but not limited to", intending to cover non-exclusive inclusion and not limited to the examples listed in the text. In addition, terms such as "first" and "second" are used to distinguish different objects rather than to describe a specific order.

[0028] The implementation of the present disclosure will be described in detail below in conjunction with specific accompanying drawings:

[0029] Figure 1 It is a schematic structural diagram of a pre-charging system for a charging pile provided in an embodiment of the present disclosure. Refer to Figure 1 This pre-charging system for a charging pile includes: a central control module, a charging detection module, a first driving module, a second driving module, a first relay, a second relay, and a resistor; the charging detection module is connected to the central control module, and the charging detection module is used to detect the connection status between the charging connector and the electric vehicle; the first end of the first driving module is connected to the central control module, the second end of the first driving module is connected to the control end of the first relay, the first end of the first relay is connected to the first end of the resistor, the second end of the resistor is used to connect to the power grid, and the second end of the first relay is used to output a charging voltage; the first end of the second driving module is connected to the central control module, the second end of the second driving module is connected to the control end of the second relay, the first end of the second relay is connected to the second end of the resistor, and the second end of the second relay is connected to the second end of the first relay.

[0030] In this embodiment, first, the charging detection module is used to continuously detect the connection status between the charging pile gun head and the electric vehicle charging interface. Once it is confirmed that the connection is normal, the central control module immediately receives the detection signal and triggers the pre-charging process. At this stage, the central control module sends a control instruction to the first driving module, and the first driving module immediately drives the first relay to close. At this time, the charging voltage provided by the power grid first passes through a preset resistor for current limiting, and then passes through the closed first relay to form a pre-charging circuit. This effectively avoids the impact on the power supply and circuit caused by a large amount of current instantaneously absorbed by components such as capacitors at the beginning of charging, and protects the battery and charging system of the electric vehicle.

[0031] As the charging process progresses, the charging current of the electric vehicle gradually stabilizes. After the central control module identifies this state through intelligent judgment, it immediately sends a control instruction to the second drive module, and at the same time stops sending signals to the first drive module, causing the first relay to disconnect. Meanwhile, the second drive module drives the second relay to close, and the charging voltage provided by the power grid is directly output to the electric vehicle through the second relay, bypassing the pre-charge resistor, thereby improving the charging efficiency and achieving fast charging. In addition, this embodiment also reduces the ineffective power consumption of the auxiliary power supply in the standby mode through a refined energy consumption management strategy, further reducing the usage cost and reflecting the intelligence and high efficiency of its working principle.

[0032] Exemplarily, assume an electric vehicle of model EV-100 comes to a charging station equipped with the above pre-charging system. The vehicle owner inserts the charging gun head of the charging pile into the charging interface of the electric vehicle, and the charging detection module immediately detects that the two are normally connected and sends this information to the central control module in the form of an electrical signal. After receiving the signal, the central control module issues a control instruction to the first drive module. The first drive module then drives the first relay, and the contacts of the first relay close. At this time, the 220V charging voltage from the power grid passes through a 50-ohm resistor and the first relay and is output to the electric vehicle for charging with a smaller current after current limiting. After about 30 seconds, the charging current of the electric vehicle stabilizes, and the central control module instead sends a control instruction to the second drive module. The second drive module drives the second relay to make its contacts close, and at the same time stops sending a control signal to the first drive module, and the contacts of the first relay disconnect. Thereafter, the 220V charging voltage no longer passes through the resistor but is directly output to the electric vehicle through the second relay, and the charging current increases, accelerating the charging speed.

[0033] It can be concluded from the above that this embodiment can instantly detect the connection state between the charging gun head and the electric vehicle interface to ensure the accurate start of the charging operation. In the pre-charging stage, the introduction of the resistor effectively limits the initial charging current, avoiding the impact of instantaneous large current on the battery of the electric vehicle and protecting the battery life and the safety of the vehicle's electrical system. As the charging enters the stable stage, this embodiment automatically switches to the second relay path, bypassing the current-limiting resistor and directly providing a higher-efficiency charging current, thus greatly shortening the charging time and improving the user experience. This not only reflects the comprehensive consideration for the charging safety of electric vehicles but also demonstrates the improvement in charging efficiency.

[0034] As Figure 1 shown, in an embodiment of the present disclosure, it further includes: a voltage sampling module; the first end of the voltage sampling module is connected to the second end of the first relay, and the second end of the voltage sampling module is connected to the central control module.

[0035] In this embodiment, the voltage sampling module closely monitors the charging voltage at the output end of the first relay and captures the voltage changes during the charging process in real time. When the electric vehicle enters the pre-charging stage, the voltage sampling module starts to work and continuously feeds the collected voltage data back to the central control module. Based on this real-time data, the central control module can accurately determine whether the charging voltage has reached a stable state. Once it is confirmed that the charging voltage is stable, the central control module timely sends a control command to the second driving module to drive the second relay to close and simultaneously disconnect the first relay, realizing a smooth switching of the charging path.

[0036] Exemplarily, suppose an electric vehicle arrives at a charging pile with the above complete functions. The vehicle owner inserts the charging gun head of the charging pile into the vehicle charging interface. The charging detection module detects a normal connection and sends a signal to the central control module. The central control module then sends an instruction to the first driving module. The first driving module drives the first relay to close, and the 380V voltage of the power grid is output to the "Future" electric vehicle through the resistor and the first relay to start pre-charging. At the same time, the voltage sampling module starts to work. Its first end is connected to the output end of the first relay to collect the charging voltage in real time. During the pre-charging process, the voltage keeps changing. After about 1 minute, the voltage data collected by the voltage sampling module shows that the voltage has become stable. The voltage sampling module feeds back the information of the stable voltage to the central control module. After receiving it, the central control module sends a control command to the second driving module. The second driving module drives the second relay to close and simultaneously stops sending signals to the first driving module, and the first relay disconnects. At this time, the 380V voltage is directly output to the electric vehicle through the second relay, and the charging current increases, entering the fast charging stage.

[0037] In this embodiment, through the real-time monitoring and feedback of the voltage sampling module, the central control module can make a decision on the switching timing of the charging path based on accurate voltage data, thus ensuring the continuity and stability of the charging process. Secondly, real-time monitoring of voltage changes helps to promptly detect and handle potential charging anomalies, such as excessive voltage fluctuations, effectively ensuring the safety of the electric vehicle battery. Finally, combined with the intelligent analysis of voltage data, the central control module can further optimize the charging strategy, improve the charging efficiency, and provide a safer, more efficient, and more convenient charging experience for users.

[0038] As Figure 2 shown, in an embodiment of the present disclosure, the first relay includes: relay K1; the first driving module includes: triode Q2; the resistor includes: resistor RL; the base of triode Q2 is connected to the central control module, the collector of triode Q2 is connected to the VCC power supply, the emitter of triode Q2 is connected to the first control end of relay K1, the second control end of relay K1 is grounded, the first end of relay K1 is connected to the first end of resistor RL, the second end of resistor RL is used to connect to the power grid, and the second end of relay K1 is used to output the charging voltage.

[0039] In this embodiment, when the central control module needs to start the pre-charging process, a high-level signal is sent to the base of the triode Q2. After receiving this signal, the triode Q2 conducts, and a path is formed between its collector and emitter. Since the collector of the triode Q2 is connected to the VCC power supply, at this time, the current flows from the VCC power supply through the collector and emitter of the triode Q2 to the first control end of the relay K1. The relay K1 is energized, and its contacts are closed. The voltage of the power grid passes through the resistor RL and then is output as the charging voltage through the first end and the second end of the closed relay K1. In the pre-charging stage, the resistor RL plays a role in current limiting, restricting the magnitude of the charging current and avoiding the impact on the circuit caused by directly connecting a large current when the voltage across loads such as capacitors is zero. When the voltage data collected by the voltage sampling module shows that the charging voltage reaches a stable state after charging for a period of time, the central control module stops sending the high-level signal to the triode Q2. The triode Q2 is cut off, the relay K1 loses power, and its contacts are disconnected, stopping the output of the charging voltage through the resistor RL.

[0040] In this embodiment, by using the triode Q2 as the driving element, the central control module realizes precise control of the relay K1, making the start and stop of the entire pre-charging process faster and more reliable. Secondly, the resistor RL, as the pre-charge resistor, effectively limits the magnitude of the current in the initial stage of charging, protecting the battery and charging system of the electric vehicle from the impact of large currents.

[0041] As Figure 2 shown, in an embodiment of the present disclosure, the first driving module further includes: a controller U1 and a variable resistor RP1; the power supply terminal of the controller U1 is connected to the emitter of the triode Q2, the adjustment terminal of the controller U1 is connected to the sliding terminal of the variable resistor RP1, the first terminal of the variable resistor RP1 is connected to the emitter of the triode Q2, the second terminal of the variable resistor RP1 is grounded, the first control end of the relay K1 is connected to the feedback end of the controller U1, the second control end of the relay K1 is connected to the input end of the controller U1, and the grounding terminal of the controller U1 is grounded.

[0042] In this embodiment, the controller U1 can adopt a constant-current chip, and in this embodiment, AL8843 is used as the constant-current chip. The VCC power supply is applied to the input end of the controller U1 after passing through the triode Q2 and the control end of the relay K1 in sequence. The first control end of the relay K1 is connected to the feedback end of the controller U1 as the sampling end. A comparator is provided inside the controller U1. When the current flowing through the control end of the relay K1 exceeds the set value, the comparator inside the controller U1 outputs a low level, so that the input end of the controller U1 is disconnected from the ground, and the control end of the relay K1 loses power. When the current drops, the relay K1 is powered on again, thereby stabilizing the average current flowing through the control end of the relay K1 and ensuring the stability of the operation of the relay K1.

[0043] In this embodiment, the first relay and the second relay can be the same relay, and the circuit structures of the first drive module and the second drive module are the same.

[0044] As Figure 3 shown, in an embodiment of the present disclosure, the charging detection module includes: a microswitch SW1 and an optocoupler U3; a first end of the microswitch SW1 is connected to the VCC power supply, a second end of the microswitch SW1 is connected to a first input end of the optocoupler U3, a second input end of the optocoupler U3 is grounded, a first output end of the optocoupler U3 is connected to the VDD power supply, and a second output end of the optocoupler U3 is connected to the central control module.

[0045] In this embodiment, the microswitch SW1 is disposed on the gun head of the charging post. When the gun head is normally connected to the interface, the microswitch SW1 is closed. At this time, current flows from the VCC power supply through the microswitch SW1 to the first input end of the optocoupler U3, causing the light-emitting diode inside the optocoupler U3 to conduct and emit light. The photosensitive triode inside the optocoupler U3 is turned on by light, and the potential of its second output end changes, and this change is transmitted to the central control module. The central control module determines whether the charging pile gun head is normally connected to the electric vehicle charging interface according to the potential change of the second output end of the optocoupler U3.

[0046] Exemplarily, it is assumed that the VCC power supply is 5V and the VDD power supply is 3.3V.

[0047] When the charging pile gun head is not inserted into the electric vehicle charging interface, the microswitch SW1 is in an open state, the light-emitting diode of the optocoupler U3 is not conducting, the photosensitive triode is not conducting, and the second output end of the optocoupler U3 outputs a low level, such as 0V, to the central control module. When the charging pile gun head is inserted into the electric vehicle charging interface, the microswitch SW1 is closed, and the current of the 5V power supply passes through the microswitch SW1 to turn on the optocoupler U3, and the second output end of the optocoupler U3 outputs a high level, such as 3.3V, to the central control module. When the central control module detects this low-level change, it determines that the gun head and the interface have been normally connected, and thus can start the subsequent charging control process.

[0048] In this embodiment, by combining the use of the microswitch and the optocoupler, not only the sensitivity and accuracy of charging detection are improved, but also the current interference or safety hazards that may be caused by direct electrical connection are avoided, enhancing the stability and safety of the system. At the same time, this design simplifies the circuit structure, reduces costs, and is convenient for integration and maintenance.

[0049] As Figure 3As shown, in an embodiment of the present disclosure, the charging detection module further includes: resistor R7, capacitor C4, triode Q1, triode Q1, capacitor C5, resistor R10, transistor Q3, and light-emitting diode LED1; the first end of resistor R7 is connected to the VCC power supply, the second end of resistor R7 is grounded through capacitor C4, the second end of resistor R7 is connected to the base of triode Q1, the collector of triode Q1 is connected to the second end of microswitch SW1, the emitter of triode Q1 is grounded through capacitor C5, the emitter of triode Q1 is connected to the control end of transistor Q1, the first end of resistor R10 is connected to the second end of microswitch SW1, the second end of resistor R10 is connected to the first end of transistor Q3, the second end of transistor Q3 is connected to the anode of light-emitting diode LED1, and the cathode of light-emitting diode LED1 is grounded.

[0050] In this embodiment, when the gun head is normally connected to the interface, microswitch SW1 closes. At this time, triode Q1 conducts, and triode Q1 operates in a switching state. After triode Q1 conducts, capacitor C5 starts to charge, and the voltage on capacitor C5 gradually increases. When the voltage on capacitor C5 exceeds the peak voltage of transistor Q3, transistor Q3 conducts, and light-emitting diode LED1 is lit. Subsequently, capacitor C5 starts to discharge, the voltage on capacitor C5 gradually decreases, the current flowing through light-emitting diode LED1 decreases, and the brightness of light-emitting diode LED1 decreases until the voltage on capacitor C5 is less than the valley voltage of crystal light Q3, at which point transistor Q3 cuts off and light-emitting diode LED1 goes out. Then capacitor C5 charges again, forming a cycle, thereby making light-emitting diode LED1 produce a breathing light effect to remind the user that the electric vehicle has entered the charging state.

[0051] Among them, resistor R7 and capacitor C4 form a buffer circuit to prevent the base current applied to triode Q1 from being too large when microswitch SW1 closes instantaneously, playing a protective role for triode Q1.

[0052] In this embodiment, through the breathing light effect of LED1, the user can intuitively understand whether the electric vehicle has entered the charging state, improving the convenience and satisfaction of use.

[0053] As Figure 2 shown, in an embodiment of the present disclosure, the voltage sampling module includes: diode D2, resistor R3, resistor R4, operational amplifier U2, resistor R6, and resistor R5; the anode of diode D2 is connected to the second end of the first relay, the cathode of diode D2 is connected to the first end of resistor R3, the second end of resistor R3 is grounded through resistor R4, the second end of resistor R3 is connected to the non-inverting input terminal of operational amplifier U2, the inverting input terminal of operational amplifier U2 is grounded through resistor R6, the output terminal of operational amplifier U2 is connected to the inverting input terminal of operational amplifier U2 through resistor R5, and the output terminal of operational amplifier U2 is connected to the central control module.

[0054] In this embodiment, after the charging voltage is output from the second terminal of the first relay, it first passes through the diode D2 for unidirectional conduction. Then the current is divided by the resistors R3 and R4, and the voltage at the second terminal of the resistor R3 is used as the input voltage to enter the non-inverting input terminal of the operational amplifier U2. The operational amplifier U2 and its peripheral resistors R5 and R6 form a non-inverting proportional amplification circuit. The inverting input terminal of the operational amplifier U2 is grounded through the resistor R6 to form a reference voltage. After being amplified by the operational amplifier U2, the output voltage signal is transmitted to the central control module through the output terminal of the operational amplifier U2. The central control module determines the state of the charging voltage according to the received voltage sampling signal, such as whether it reaches a steady state, etc.

[0055] In this embodiment, an effective sampling and linear amplification of the voltage signal are achieved through a simple circuit structure, and by comparing with a preset voltage steady standard, it is determined whether to switch the charging mode.

[0056] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the present disclosure in each embodiment.

Claims

1. A charging pile pre-charging system, characterized in that: include: A central control module, a charging detection module, a first driving module, a second driving module, a first relay, a second relay and a resistor; The charging detection module is connected to the central control module, and the charging detection module is used to detect the connection status between the charging connector and the electric vehicle; The first end of the first driving module is connected to the central control module, the second end of the first driving module is connected to the control end of the first relay, the first end of the first relay is connected to the first end of the resistor, the second end of the resistor is used to connect to the power grid, and the second end of the first relay is used to output a charging voltage; The first end of the second driving module is connected to the central control module, the second end of the second driving module is connected to the control end of the second relay, the first end of the second relay is connected to the second end of the resistor, and the second end of the second relay is connected to the second end of the first relay.

2. A charging pile pre-charging system as claimed in claim 1, characterized in that: Also includes: Voltage sampling module; The first end of the voltage sampling module is connected to the second end of the first relay, and the second end of the voltage sampling module is connected to the central control module.

3. A charging pile pre-charging system as claimed in claim 1, characterized in that: The first relay includes: a relay K1; the first driving module includes: a transistor Q2; the resistor includes: a resistor RL; The base of the transistor Q2 is connected to the central control module, the collector of the transistor Q2 is connected to the VCC power supply, the emitter of the transistor Q2 is connected to the first control end of the relay K1, the second control end of the relay K1 is grounded, the first end of the relay K1 is connected to the first end of the resistor RL, the second end of the resistor RL is used to connect to the power grid, and the second end of the relay K1 is used to output a charging voltage.

4. A charging pile pre-charging system as claimed in claim 3, characterized in that: The first driving module further includes: a controller U1 and a variable resistor RP1; The power supply end of the controller U1 is connected to the emitter of the transistor Q2, the adjustment end of the controller U1 is connected to the sliding end of the variable resistor RP1, the first end of the variable resistor RP1 is connected to the emitter of the transistor Q2, the second end of the variable resistor RP1 is grounded, the first control end of the relay K1 is connected to the feedback end of the controller U1, the second control end of the relay K1 is connected to the input end of the controller U1, and the ground end of the controller U1 is grounded.

5. A charging pile pre-charging system as claimed in claim 1, characterized in that: The charging detection module includes: a micro switch SW1 and an optical coupler U3; The first end of the micro switch SW1 is connected to the VCC power supply, the second end of the micro switch SW1 is connected to the first input end of the optocoupler U3, the second input end of the optocoupler U3 is grounded, the first output end of the optocoupler U3 is connected to the VDD power supply, and the second output end of the optocoupler U3 is connected to the central control module.

6. A charging pile pre-charging system as claimed in claim 5, characterized in that: The charging detection module also includes: a resistor R7, a capacitor C4, a transistor Q1, a transistor Q1, a capacitor C5, a resistor R10, a transistor Q3 and a light emitting diode LED1; The first end of the resistor R7 is connected to the VCC power supply, the second end of the resistor R7 is grounded through the capacitor C4, the second end of the resistor R7 is connected to the base of the transistor Q1, the collector of the transistor Q1 is connected to the second end of the micro switch SW1, the emitter of the transistor Q1 is grounded through the capacitor C5, the emitter of the transistor Q1 is connected to the control end of the transistor Q1, the first end of the resistor R10 is connected to the second end of the micro switch SW1, the second end of the resistor R10 is connected to the first end of the transistor Q3, the second end of the transistor Q3 is connected to the anode of the light emitting diode LED1, and the cathode of the light emitting diode LED1 is grounded.

7. A charging pile pre-charging system as claimed in claim 2, characterized in that: The voltage sampling module includes: a diode D2, a resistor R3, a resistor R4, an operational amplifier U2, a resistor R6 and a resistor R5; The anode of the diode D2 is connected to the second end of the first relay, the cathode of the diode D2 is connected to the first end of the resistor R3, the second end of the resistor R3 is grounded through the resistor R4, the second end of the resistor R3 is connected to the non-inverting input end of the operational amplifier U2, the inverting input end of the operational amplifier U2 is grounded through the resistor R6, the output end of the operational amplifier U2 is connected to the inverting input end of the operational amplifier U2 through the resistor R5, and the output end of the operational amplifier U2 is connected to the central control module.

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