Charging gun and circuit and control method for removing abnormity of charging interface of charging gun

Abstract

The invention relates to a charging gun and a charging interface abnormity removing circuit and a control method thereof, and belongs to the field of charging guns. A base electrode of a first triode in the circuit is provided with a first interface used for being connected with an MCU; a first branch is arranged between the emitter of the first triode and the grounding resistor, and the first branch is connected with the emitter of the third triode; the collector of the third triode is grounded through a grounding resistor; a second branch is arranged between the collector of the third triode and the grounding resistor; the second branch is connected in series with a direct current contactor and grounded; the base electrode of the third triode is connected with the collector electrode of a second triode, the emitter electrode of the second triode is grounded, and the base electrode of the second triode is provided with a second interface for receiving a charging interface state signal; when the signal of the charging gun is abnormal, the direct current contactor is controlled to be powered off through the on-off state of the triode in the circuit, and when it is detected that the charging interface is disconnected, the output loop is rapidly cut off.

Description

Technical Field

[0001] This invention relates to a charging gun and a circuit and control method for cutting off abnormalities in its charging interface, belonging to the field of charging guns. Background Technology

[0002] The wave of vehicle electrification is sweeping the globe, with countries around the world gradually rolling out bans on the sale of gasoline-powered cars. In my country, the number of domestically produced electric vehicles is also steadily increasing, and the scenarios for charging electric vehicles are becoming more and more common.

[0003] The common method for charging electric vehicles involves connecting a DC charger (i.e., charging the battery by directly outputting controllable DC power) to the charging gun socket of the electric vehicle using a charging gun. During charging, electrical energy is transferred through this connection method. According to the charging shutdown procedure specified in GB / T 18487.1 (the relevant standard for conductive charging systems for electric vehicles), when charging stops, the charger controls the charging module to shut down, and when the output current reaches below 5A, the charger disconnects the output DC contactors C1 and C2, the charging gun's electronic lock unlocks, and the user can remove the gun. At the time of removal, the charging interface has no power. However, if the charging interface is suddenly disconnected during energy transfer, there is a risk of arcing (the phenomenon of current continuously discharging in the air; when the voltage breaks down the air gap, the gas ionizes to form a conductive channel, generating a high-temperature arc). This is mainly related to the following reasons: 1. High voltage: DC chargers typically output high voltages, such as hundreds of volts or kilovolts. Removing the gun while it is energized will cause an arc between the high voltage components. 2. High Current: DC chargers output high current, typically hundreds or even thousands of amperes. Disconnecting the charger while it's energized can cause an electric arc due to the interruption of current flow. 3. Disconnection Speed: The faster the charger is disconnected while energized, the faster the current is interrupted, increasing the likelihood of an electric arc.

[0004] The supercharging interface boasts a voltage of 1000V and a maximum current of 600A. Compared to traditional DC charging interfaces (750V, 250A), this significantly increases the risks of arcing, insulation breakdown, and pin burning. Furthermore, compared to the 2015 national standard charging interface, the connector pins have been reduced from 9 to 7, and the charging gun lacks an electronic lock; the electronic lock control resides on the vehicle side. If the electronic lock fails, the risk of arcing caused by users plugging and unplugging while the circuit is energized will be greatly increased.

[0005] In the same amount of time, the arc energy of a DC charger is directly proportional to the product of voltage and current. The arc energy of a high-power supercharger is more than three times that of a regular DC charger. Therefore, it is necessary to design an anti-arc-strike scheme for the supercharger system to ensure the safety of equipment and personnel.

[0006] Additionally, existing DC chargers require approximately 45ms from disconnecting the charging gun CC1 to the complete disconnection of the output DC contactor. (See...) Figure 1 The following is a flowchart of the charging interface disconnection process in the existing technology for abnormal gun removal: The coil of the DC output contactor is controlled by the onboard relay of the charging controller. It takes 10ms for the MCU to receive the CC1 disconnection signal; it takes 15ms for the MCU to control the onboard relay to de-energize the DC output contactor coil; it takes 20ms for the DC output contactor coil to be de-energized and completely disconnected. Therefore, it takes a total of 45ms from gun removal to complete de-energization of the bus. According to gun removal tests, under normal circumstances, the time from CC1 disconnection to DC+ disconnection is 22.3ms when a person removes the gun. Therefore, if the person removes the gun quickly, the 45ms disconnection time cannot avoid the risk of arcing. Summary of the Invention

[0007] The purpose of this invention is to provide a circuit and control method for cutting off abnormalities in a charging gun and its charging interface, in order to solve the problem that existing charging interface disconnection methods cannot avoid the risk of arcing when the gun is abnormally disconnected. This invention enables rapid disconnection of the output circuit, so that the energy drops rapidly when the charging gun head and the gun base are completely separated, thus avoiding the risk of arcing.

[0008] To achieve the above objectives, on the one hand, the present invention proposes a circuit for cutting off abnormal charging interfaces of a charging gun, including multiple transistors, wherein the base of the first transistor is provided with a first interface for connecting to an MCU, its collector is provided with a constant power supply, and its emitter is grounded through a grounding resistor. A first branch is opened between the emitter of the first transistor and the grounding resistor, and the first branch is connected to the emitter of the third transistor; the collector of the third transistor is grounded through the grounding resistor. A second branch is opened between the collector of the third transistor and the grounding resistor; a DC contactor is connected in series in the second branch and grounded; the base of the third transistor is connected to the collector of the second transistor, the emitter of the second transistor is grounded, and the base of the second transistor is provided with a second interface for receiving the charging interface status signal.

[0009] Furthermore, resistors are provided between the base of the first transistor and the first interface, and between the base of the second transistor and the second interface.

[0010] Furthermore, a resistor is provided between the base of the third transistor and the collector of the second transistor.

[0011] Furthermore, the second potential point of the second branch is connected in series with the positive terminal of the DC contactor coil, and the negative terminal of the high-voltage DC contactor coil is grounded.

[0012] On the other hand, the present invention also proposes a control method for the circuit cutoff of abnormal charging gun charging interface. In the circuit, the base of the first transistor is provided with a first interface for connection with MCU, its collector is provided with a constant power supply, and its emitter is grounded through a grounding resistor; a first branch is opened between the emitter of the first transistor and the grounding resistor, and the first branch is connected to the emitter of the third transistor; the collector of the third transistor is grounded through a grounding resistor; a second branch is opened between the collector of the third transistor and the grounding resistor; a DC contactor is connected in series in the second branch and grounded; the base of the third transistor is connected to the collector of the second transistor, the emitter of the second transistor is grounded, and the base of the second transistor is provided with a second interface for receiving charging interface status signals. The control method includes: when the charging gun signal is abnormal, controlling the DC contactor to lose power by controlling the on / off state of the transistor in the circuit.

[0013] Furthermore, in response to the second interface receiving a signal used to determine an abnormality in the charging gun's charging interface, the base of the second transistor receives a low-level signal; in response to the low-level signal, both the second and third transistors switch to an off-state, thereby disconnecting the DC contactor in the second branch.

[0014] Furthermore, it also includes: when the charging gun signal is normal, using the controller signal received by the first interface to control the power on / off of the DC contactor.

[0015] Furthermore, when the second interface receives a signal to confirm that the charging gun's charging interface is normal, and the first interface receives a high-level signal input from the MCU, in response to the first interface receiving the high-level signal input from the MCU, the first transistor, the second transistor, and the third transistor are all turned on, so that the DC contactor is closed.

[0016] Furthermore, when the second interface receives a signal to confirm that the charging gun's charging interface is normal, and the first interface receives a low-level signal input from the MCU, in response to the first interface receiving the low-level signal input from the MCU, the first and third transistors are controlled to switch to non-conducting, and the second transistor is switched to conducting, so that the DC contactor is disconnected.

[0017] On the other hand, the present invention also proposes a charging gun, the charging gun including a controller, the controller being used to execute the following control method: when the charging gun signal is abnormal, the DC contactor is de-energized by controlling the on / off state of the transistor in the circuit, wherein the base of the first transistor in the circuit is provided with a first interface for connection with an MCU, its collector is provided with a constant power supply, and its emitter is grounded through a grounding resistor; a first branch is opened between the emitter of the first transistor and the grounding resistor, and the first branch is connected to the emitter of a third transistor; the collector of the third transistor is grounded through a grounding resistor; a second branch is opened between the collector of the third transistor and the grounding resistor; a DC contactor is connected in series in the second branch and grounded; the base of the third transistor is connected to the collector of the second transistor, the emitter of the second transistor is grounded, and the base of the second transistor is provided with a second interface for receiving the charging interface status signal.

[0018] Furthermore, in response to the second interface receiving a signal used to determine an abnormality in the charging gun's charging interface, the base of the second transistor receives a low-level signal; in response to the low-level signal, both the second and third transistors switch to an off-state, thereby disconnecting the DC contactor in the second branch.

[0019] Furthermore, it also includes: when the charging gun signal is normal, using the controller signal received by the first interface to control the power on / off of the DC contactor.

[0020] Furthermore, when the second interface receives a signal to confirm that the charging gun's charging interface is normal, and the first interface receives a high-level signal input from the MCU, in response to the first interface receiving the high-level signal input from the MCU, the first transistor, the second transistor, and the third transistor are all turned on, so that the DC contactor is closed.

[0021] Furthermore, when the second interface receives a signal to confirm that the charging gun's charging interface is normal, and the first interface receives a low-level signal input from the MCU, in response to the first interface receiving the low-level signal input from the MCU, the first and third transistors are controlled to switch to non-conducting, and the second transistor is switched to conducting, so that the DC contactor is disconnected.

[0022] The beneficial effects of this invention are as follows: the base of the first transistor in the circuit is provided with a first interface for connection with the MCU, its collector is provided with a constant power supply, and its emitter is grounded through a grounding resistor; a first branch is opened between the emitter of the first transistor and the grounding resistor, and the first branch is connected to the emitter of the third transistor; the collector of the third transistor is grounded through a grounding resistor; a second branch is opened between the collector of the third transistor and the grounding resistor; a DC contactor is connected in series in the second branch and grounded; the base of the third transistor is connected to the collector of the second transistor, the emitter of the second transistor is grounded, and the base of the second transistor is provided with a second interface for receiving the charging interface status signal; the control method includes: when the charging gun signal is abnormal, the DC contactor is de-energized by controlling the on / off state of the transistor in the circuit; when the charging interface is detected to be disconnected, the high-voltage DC output contactor of the charger can be quickly disconnected without the MCU; combined with the fact that the DC contactor has the ability to disconnect under load, the output circuit can be quickly cut off, so that the energy drops rapidly when the charging gun head and the gun holder are completely separated, avoiding the risk of arcing. Attached Figure Description

[0023] Figure 1 This is a flowchart of the charging interface disconnection process in the existing technology when the charging gun is abnormally unplugged; Figure 2 This is a topology diagram of a circuit for cutting off abnormal charging interfaces of a charging gun proposed in this invention in a practical application scenario. Figure 3 This is a flowchart illustrating the control method for the disconnection circuit of a charging gun charging interface abnormality proposed in this invention, applied to a real-world abnormal gun unplugging scenario where the charging interface is disconnected. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0025] The inventive concept of this invention is as follows: when the charging interface is detected to be disconnected (i.e., the CC1 signal is disconnected), instead of the traditional method of disconnecting the high-voltage DC output contactor of the charger controlled by the MCU, the invention cleverly utilizes the load-bearing breaking capability of the DC contactor to directly and quickly disconnect the output circuit by switching the circuit on and off with the transistor, so that the energy drops rapidly when the charging gun head and the gun holder are completely separated, thus avoiding the risk of arcing.

[0026] Circuit implementation method 1: This invention proposes a circuit for cutting off abnormal charging interface of a charging gun, which includes multiple transistors. The base of the first transistor is provided with a first interface for connection with an MCU, the collector of the first transistor is provided with a constant power supply, and the emitter of the first transistor is grounded through a grounding resistor. Here, after the first interface is connected to the MCU, it can receive the level signal input by the MCU at any time, so that when the charging gun voltage signal is normal, the MCU controls the on / off of the DC contactor.

[0027] A first branch is opened between the emitter of the first transistor and the grounding resistor, and the first branch is connected to the emitter of the third transistor; the collector of the third transistor is grounded through the grounding resistor; a second branch is opened between the collector of the third transistor and the grounding resistor; a DC contactor is connected in series in the second branch and grounded; the base of the third transistor is connected to the collector of the second transistor, the emitter of the second transistor is grounded, and the base of the second transistor is provided with a second interface for receiving the charging interface status signal; it should be noted that the first and second transistors are NPN type; the third transistor is PNP type.

[0028] Circuit implementation method 2: like Figure 2 The diagram shown is a topology of a circuit for cutting off an abnormal charging port interface proposed in this invention in a practical application scenario. The circuit includes a first interface for connecting to an MCU, resistors R1 to R5, transistors Q1 to Q3, a 12V power supply, and a second interface for connecting to the charging gun CC1. First, one end of the first interface is connected to the MCU, and the other end is connected in sequence to the base of resistor R1 and transistor Q1; the collector of transistor Q1 is connected to a 12V power supply, and the emitter of transistor Q1 is grounded through resistor R2 used for voltage division. The function of resistor R1 is to limit the current and protect the MCU.

[0029] Secondly, a first potential point OUT1 (i.e., the first branch) is opened between the emitter of transistor Q1 and R2, and the first potential point OUT1 is connected to the emitter of transistor Q3; the collector of transistor Q3 is grounded through resistor R3 used for voltage division.

[0030] Continuing, a second potential point OUT2 (i.e., the second branch) is opened between the collector of transistor Q3 and resistor R3; the second potential point OUT2 is connected to the positive terminal of high voltage DC contactor coil C1 / C2, and the negative terminal of high voltage DC contactor coil C1 / C2 is grounded.

[0031] Finally, one end of the second interface is connected to the CC1 status signal, and the other end is sequentially connected to the resistor R4 used to limit the current and protect the input signal terminal of the charging gun and the base of transistor Q2; the collector of transistor Q2 is connected to the base of transistor Q3 through the resistor R5 used to protect transistor Q3, and the emitter of transistor Q2 is grounded.

[0032] Detailed implementation method 1: This invention also proposes a control method for a cutoff circuit in case of charging gun interface malfunction. When the charging gun signal is abnormal, the DC contactor is de-energized by controlling the on / off state of the transistors in the circuit. Specifically, based on the cutoff circuit, in response to the second interface receiving a signal used to determine the charging gun interface malfunction, the base of the second transistor receives a low-level signal. In response to the low-level signal, both the second and third transistors switch to an off-state, causing the DC contactor in the second branch to disconnect. This achieves control of the DC contactor based on the cutoff circuit, utilizing its load-bearing breaking capability, instead of the traditional MCU-based control method, when the charging gun interface malfunctions.

[0033] Furthermore, when the charging gun signal is normal, the MCU still controls the energization / de-energization of the DC contactor; that is, the controller signal received from the first interface controls the energization / de-energization of the DC contactor. Specifically, when the second interface receives a signal confirming that the charging gun interface is normal, and the first interface receives a high-level signal input from the MCU, in response to the high-level signal received from the MCU by the first interface, the first, second, and third transistors all conduct, causing the DC contactor to close.

[0034] When the second interface receives a signal to confirm that the charging gun's charging interface is normal, and the first interface receives a low-level signal input from the MCU, in response to the first interface receiving the low-level signal input from the MCU, the first and third transistors are controlled to switch to non-conducting, and the second transistor is switched to conducting, so that the DC contactor is disconnected, realizing "hybrid" control of the DC contactor and effectively avoiding the risk of arcing caused by abnormal gun removal in traditional methods.

[0035] Method Detailed Implementation 2: Below, we will combine practical application scenarios and Figure 2 The present invention provides an explanation of a control method for the circuit cutoff of abnormal charging gun interface proposed in this invention.

[0036] (a) If the voltage signal of the charging gun CC1 is normal, that is, the output signal INT of the charging gun CC1 is a high-level signal, then the MCU controls the energization or de-energization of the high-voltage DC contactor coils C1 / C2, and the corresponding high-voltage DC contactor closes or opens. The working steps are as follows: 1. When the MCU inputs a high level, the high-voltage DC contactor coils C1 / C2 are energized: When the MCU inputs a high level, the base of Q1 is connected to a high level through R1, and the emitter of Q1 is grounded through R2, forming a loop. Q1 is turned on, and the collector of Q1 is connected to 12V. After turning on, the voltage drop between the emitter and collector of Q1 is 0.3V, the voltage at OUT1 is 11.7V, and INT is high. The emitter of Q2 is grounded, and the base of Q2 is connected to INT through R4, making Q2 turn on. The emitter of Q3 is connected to OUT and 11.7V, and the base is grounded through R5 and the turned-on Q2, forming a loop. Thus, Q3 is turned on, and the voltage drop between the emitter and collector of Q3 is 0.3V. Therefore, the voltage at the output point of OUT2 is +11.4V, the coils C1 / C2 are energized, and the high-voltage DC contactor is closed.

[0037] 2. When the MCU input is low, the high-voltage DC contactor coils C1 / C2 are de-energized: When the MCU input is low, the emitter of Q1 is grounded through R2, and the base of Q1 is connected to the MCU through R1. At this time, Q1 is not conducting, OUT1 is grounded through R2, so the voltage at OUT1 is 0, INT is high, Q2 is conducting, the emitter of Q3 is connected to 0V, and the base forms a loop through R5 and the conducting Q2, obtaining a low level. Q3 is not conducting, so OUT2 is grounded through R3, the voltage at the OUT2 output point is 0V, the coils C1 / C2 are de-energized, and the high-voltage DC contactor is disconnected.

[0038] (ii) If the user accidentally pulls out the gun, causing the CC1 voltage signal to be abnormal (i.e., INT is low), then the high-voltage DC contactor coils C1 / C2 do not need to be immediately de-energized through the MCU, and the corresponding high-voltage DC contactor will disconnect. The operating steps are as follows: When the INT input is low, the base of Q2 is connected to INT via R4 to obtain a low level. Since the emitter of Q2 is grounded, its collector and emitter are not conducting. The base of Q3 is floating, so its collector and emitter cannot conduct. The voltage at OUT2 is 0, coils C1 / C2 are immediately de-energized, and the high-voltage DC contactor disconnects (see...). Figure 3 The time from INT signal input to de-energizing the high-voltage DC contactor coil is only in the μs range, without MCU control. Therefore, the charging interface disconnection is only related to the action time of the high-voltage DC contactor itself, which improves the safety of the charging system.

[0039] On the other hand, the present invention also proposes a charging gun, which includes a controller for executing the control method described above. For specific implementations of the charging gun, please refer to the circuit specific implementation 1-2 and the method specific implementation 1-2, which will not be repeated here.

[0040] In summary, when the voltage signal of CC1 is normal, the MCU normally controls the energization or de-energization of the high-voltage DC contactor coil. When the CC1 signal is abnormal, the high-voltage DC contactor coil is de-energized directly without going through the MCU. This improves the charging pile's response speed to abnormal gun removal, CC1 disconnection, and other situations, avoids dangerous situations such as arcing, and ensures the safety of equipment and personnel.

Claims

1. A cut-off circuit for abnormal charging interface of a charging gun, characterized in that, The circuit comprises a plurality of triodes, wherein the base of the first triode is provided with a first interface for connection with the MCU, the collector of the first triode is provided with a constant power supply, and the emitter of the first triode is grounded through a grounding resistor; A first branch is opened between the emitter of the first triode and the grounding resistor, and the first branch is connected to the emitter of the third triode; A second branch is opened between the collector of the third triode and the grounding resistor, and a DC contactor is connected in series in the second branch and grounded; 2. The cut-off circuit of abnormal charging interface of charging gun according to claim 1, characterized in that, The base of the third triode is connected to the collector of the second triode, the emitter of the second triode is grounded, and the base of the second triode is provided with a second interface for receiving a charging interface state signal.

3. The cut-off circuit for charging gun charging interface abnormality according to claim 1, characterized in that, Resistors are arranged between the base of the first triode and the first interface, and between the base of the second triode and the second interface.

4. The cutout circuit for abnormal charging interface of a charging gun according to claim 1, characterized in that, A resistor is arranged between the base of the third triode and the collector of the second triode.

5. A control method of a cut-off circuit of an abnormal charging interface of a charging gun, characterized by, The second potential point of the second branch is connected in series to the positive pole of the DC contactor coil, and the negative pole of the high-voltage DC contactor coil is grounded. The circuit comprises a plurality of triodes, wherein the base of the first triode is provided with a first interface for connection with the MCU, the collector of the first triode is provided with a constant power supply, and the emitter of the first triode is grounded through a grounding resistor; a first branch is opened between the emitter of the first triode and the grounding resistor, and the first branch is connected to the emitter of the third triode; the collector of the third triode is grounded through a grounding resistor; a second branch is opened between the collector of the third triode and the grounding resistor, and a DC contactor is connected in series in the second branch and grounded; the base of the third triode is connected to the collector of the second triode, the emitter of the second triode is grounded, and the base of the second triode is provided with a second interface for receiving a charging interface state signal.

6. The control method of claim 5, wherein The control method comprises: when the charging gun signal is abnormal, controlling the DC contactor to lose power through the on-off state of the triodes in the circuit.

7. The control method of the cut-off circuit of the charging gun charging interface abnormality according to claim 5, characterized by, In response to the second interface receiving a signal for determining that the charging gun charging interface is abnormal, the base of the second triode obtains a low-level signal; in response to the low-level signal, the second triode and the third triode are switched to an off state, so that the DC contactor in the second branch is opened. Further comprising:

8. The control method of claim 7, wherein When the charging gun signal is normal, the controller signal received by the first interface is used to control the on-off of the DC contactor.

9. The control method of claim 7, wherein When the second interface receives a signal for determining that the charging gun charging interface is normal, and the first interface receives a high-level signal input by the MCU, in response to the first interface receiving the high-level signal input by the MCU, the first triode, the second triode, and the third triode are all turned on, so that the DC contactor is closed.

10. A charging gun, characterized in that, When the second interface receives a signal for determining that the charging gun charging interface is normal, and the first interface receives a low-level signal input by the MCU, in response to the first interface receiving the low-level signal input by the MCU, the first triode and the third triode are controlled to switch to an off state, and the second triode is controlled to switch to an on state, so that the DC contactor is opened. The charging gun comprises a controller, and the controller is used to execute the control method according to any one of claims 5-9.

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