Reverse pre-charging control method and system

Abstract

The invention discloses a reverse pre-charging control system and method, and belongs to the technical field of new energy, and the method comprises the steps that a vehicle control unit outputs a high voltage increasing instruction to a battery management module, and the battery management module executes pre-detection on a main relay according to the high voltage increasing instruction; the storage battery management module outputs pre-charging current to the bidirectional direct-current converter; the bidirectional direct-current converter verifies the pre-charging trigger condition, and under the condition that the pre-charging trigger condition passes verification, the bidirectional direct-current converter boosts the obtained first voltage to a target voltage and outputs electric energy of the target voltage to the bus capacitor to execute pre-charging; and under the condition that the pre-charging completion condition is met, closing the main relay to complete pre-charging. According to the invention, the bidirectional working principle of the bidirectional direct-current converter is utilized, the low-voltage electric energy output by the storage battery is boosted to the target high voltage to complete pre-charging, special devices such as a pre-charging relay and a pre-charging resistor do not need to be additionally arranged, and the hardware layout of a high-voltage system of the whole vehicle is simplified.

Description

Technical Field

[0001] This application relates to the field of new energy technology, specifically to a reverse pre-charge control method and system. Background Technology

[0002] As the electric vehicle market grows, consumers' demands for intelligent features and everyday functionality in electric vehicles are also increasing. One of the core technological requirements for electric vehicles is the safe and efficient operation of the high-voltage system. Currently, the mainstream high-voltage pre-charging solutions for electric vehicles in the industry generally adopt a pre-charging circuit constructed by setting up a pre-charging relay and a pre-charging resistor inside the battery pack. This circuit pre-charges the bus capacitor of the vehicle's high-voltage controller to achieve a smooth power-on of the high-voltage system. This solution significantly increases the hardware complexity of the battery pack due to the need for additional dedicated components such as pre-charging relays and pre-charging resistors. Summary of the Invention

[0003] This invention provides a reverse pre-charge control method and system, which aims to solve the technical problem of structural complexity caused by the need to set up additional pre-charge relays and pre-charge resistors for high-voltage pre-charge of electric vehicles.

[0004] In a first aspect, embodiments of this application provide a reverse pre-charge control method, comprising the following steps: The vehicle controller outputs a high-voltage command to the battery management module, and the battery management module performs a pre-detection on the main relay according to the high-voltage command. If the pre-detection passes, the battery management module outputs a pre-charge command signal to the bidirectional DC-DC converter, and the battery management module outputs a pre-charge current to the bidirectional DC-DC converter. The bidirectional DC-DC converter verifies the precharge trigger condition. If the precharge trigger condition is verified, the bidirectional DC-DC converter boosts the first voltage obtained by the precharge current to the target voltage and outputs the target voltage to the bus capacitor to perform precharge. The battery management module and the bidirectional DC-DC converter acquire the pre-charge process parameters generated by the pre-charge of the bus capacitor, and detect the pre-charge process parameters respectively. When the pre-charge process parameters meet the pre-charge completion conditions, the main relay is closed to complete the pre-charge.

[0005] In one embodiment of this application, the main relay includes a main positive relay and a main negative relay; the battery management module performs a pre-detection on the main relay according to the high-voltage command, including: the battery management module detecting whether the main negative relay is stuck; if the main negative relay is stuck, the battery management module determines that the result of the pre-detection is a failure and exits the reverse pre-charging process; if the main negative relay is not stuck, the battery management module determines that the result of the pre-detection is a success.

[0006] In one embodiment of this application, the reverse precharge control method further includes: when the pre-detection passes, the battery management module closes the main negative relay.

[0007] In one embodiment of this application, the battery management module includes a battery pack, the positive terminal of the battery pack is connected to the first terminal of the bus capacitor through the main positive relay, and the negative terminal of the battery pack is connected to the second terminal of the bus capacitor through the main negative relay; the precharge command signal includes a precharge enable signal and the target voltage, wherein the target voltage is the real-time voltage of the battery pack.

[0008] In one embodiment of this application, the bidirectional DC-DC converter verifies the precharge trigger condition by: detecting whether the voltage fluctuation amplitude of the target voltage within a preset time is within a preset fluctuation range, and detecting whether the first voltage is greater than a preset voltage; if the voltage fluctuation amplitude of the target voltage does not exceed the preset fluctuation range, and the first voltage is greater than the preset voltage, the bidirectional DC-DC converter determines that the precharge trigger condition verification result is passed.

[0009] In one embodiment of this application, the pre-charge process parameters include pre-charge time and the voltage difference across the main positive relay; the battery management module and the bidirectional DC-DC converter acquire the pre-charge process parameters generated by the pre-charge of the bus capacitor, and respectively detect the pre-charge process parameters, including: The battery management module obtains the voltage difference across the main positive relay, and the bidirectional DC-DC converter obtains the pre-charge time. If the pre-charge time is within a preset timeout period and the voltage difference across the main positive relay is less than a preset voltage difference, the battery management module determines that the pre-charge process parameters meet the pre-charge completion conditions.

[0010] In one embodiment of this application, the bidirectional DC-DC converter boosts the first voltage obtained by the pre-charge current and outputs the target voltage electrical energy to the bus capacitor. The bidirectional DC-DC converter further includes: the bidirectional DC-DC converter judging in real time whether there is a fault in the boosting process. If there is a fault, the bidirectional DC-DC converter stops boosting and exits the reverse pre-charge execution.

[0011] In one embodiment of this application, the first voltage output by the battery management module is 9V~16V.

[0012] In one embodiment of this application, the pre-charging current output by the battery management module is 10A~60A.

[0013] Secondly, embodiments of this application also provide a reverse pre-charge control system, comprising: The vehicle controller is used to output high-voltage commands; The battery management module is used to receive the high voltage command, perform pre-detection on the main relay according to the high voltage command, and output a pre-charge command signal to the bidirectional DC-DC converter if the pre-detection is successful. The battery management module is used to output a pre-charge current to the bidirectional DC-DC converter and provide a first voltage; A bidirectional DC-DC converter is used to verify the precharge trigger conditions. If the verification is successful, the first voltage obtained is boosted to the target voltage according to the precharge current, and the electrical energy of the target voltage is output to the bus capacitor to perform precharge. The battery management module and the bidirectional DC-DC converter are also used to acquire and detect the pre-charge process parameters generated by the pre-charge of the bus capacitor, and control the main relay to close when the pre-charge process parameters meet the pre-charge completion conditions.

[0014] The beneficial effects of this application are as follows: This application issues a high-voltage command through the vehicle controller, the battery management module outputs a pre-charge command signal to the bidirectional DC-DC converter, and the battery management module outputs a pre-charge current to the bidirectional DC-DC converter; by utilizing the bidirectional working principle of the bidirectional DC-DC converter, the low-voltage electrical energy output by the battery is boosted to the target high voltage to complete the pre-charge, without the need for additional pre-charge relays, pre-charge resistors and other dedicated devices, thus simplifying the hardware layout of the vehicle's high-voltage system. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the steps of the reverse pre-charge control method provided in the embodiments of this application; Figure 2 This is a schematic flowchart of the reverse pre-charge control method provided in the embodiments of this application; Figure 3This is an architecture diagram of the reverse precharge control system provided in the embodiments of this application.

[0017] Explanation of reference numerals in the attached figures: 1. Vehicle controller; 2. Battery management module; 3. Bidirectional DC-DC converter; 4. Battery management module; 5. Bus capacitor; 61. Main positive relay; 62. Main negative relay. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] like Figures 1 to 3 As shown, an embodiment of this application provides a reverse precharge control method, including the following steps: In step S1, the vehicle controller 1 outputs a high-voltage command to the battery management module 2, and the battery management module 2 performs a pre-detection on the main relay according to the high-voltage command.

[0021] In step S2, if the pre-detection passes, the battery management module 2 outputs a pre-charge command signal to the bidirectional DC-DC converter 3, and the battery management module 4 outputs a pre-charge current to the bidirectional DC-DC converter 3.

[0022] In step S3, the bidirectional DC-DC converter 3 verifies the pre-charge trigger condition. If the pre-charge trigger condition is verified, the bidirectional DC-DC converter 3 boosts the obtained first voltage to the target voltage according to the pre-charge current and outputs the target voltage electrical energy to the bus capacitor 5 to perform pre-charge.

[0023] In step S4, the battery management module 2 and the bidirectional DC-DC converter 3 acquire the pre-charge process parameters generated by the pre-charge of the bus capacitor 5, and detect the pre-charge process parameters respectively. When the pre-charge process parameters meet the pre-charge completion conditions, the main relay is closed to complete the pre-charge.

[0024] like Figure 3 As shown, in some embodiments, the main relay includes a main positive relay 61 and a main negative relay 62; the battery management module 2 performs a pre-detection on the main relay according to the high-voltage command, including: the battery management module 2 detecting whether the main negative relay 62 is stuck. If the main negative relay 62 is stuck, the battery management module 2 determines that the pre-detection result is failed and exits the reverse pre-charging process; if the main negative relay 62 is not stuck, the battery management module 2 determines that the pre-detection result is passed.

[0025] In step S1, the battery management module 2 performs a pre-test on the main relay according to the high-voltage command for self-testing before pre-charging the bus capacitor 5. The vehicle controller 1 in this application can be an independent vehicle controller unit (VCU) or a two-in-one central controller (High-Power Controller, HPC) integrating the vehicle controller and the body control module (BCM).

[0026] After confirming that the vehicle is allowed to receive high voltage, the vehicle controller 1 sends a high voltage command to the battery management system (BMS). Specifically, the high voltage command is transmitted via the controller area network bus (CAN) to initiate the high voltage power-on process.

[0027] After receiving the high-voltage command, battery management module 2 performs a sticking detection on the main negative relay 62. The detection logic is as follows: Battery management module 2 determines whether the relay contacts are stuck by collecting the voltage signal and on / off feedback across the high-voltage main negative relay 62. If stuck, the high-voltage circuit will be directly turned on without pre-charging, causing a large current surge. By detecting whether the main negative relay 62 is stuck, the risk of relay failure is eliminated, allowing the subsequent pre-charging circuit to be safely turned on and off according to the logic of the reverse pre-charging control method provided in this application.

[0028] If the test result shows that the high-voltage main negative relay 62 is stuck, the battery management module 2 sends a fault message to the vehicle controller 1 and directly exits the reverse pre-charge process, preventing the vehicle's high-voltage system from being powered on. If the test result shows that the high-voltage main negative relay 62 is not stuck, the battery management module 2 confirms that the pre-charge start safety conditions are met, and the process proceeds to the next step S2. Simultaneously, if the pre-test passes, the battery management module 2 controls the closure of the main negative relay 62.

[0029] Battery management module 2 includes a battery pack, the voltage of which serves as the target voltage reference for reverse pre-charging, such as 800V. Battery management module 2 determines the target pre-charging voltage by monitoring the voltage status of the battery pack in real time.

[0030] This application establishes a controllable connection between the battery pack and the bus capacitor 5 using a main positive relay 61 and a main negative relay 62. The positive output terminal of the battery pack is connected to the first terminal of the main positive relay 61, and the second terminal of the main positive relay 61 is connected to the first terminal of the bus capacitor 5. The negative output terminal of the battery pack is connected to the first terminal of the main negative relay 62, and the second terminal of the main negative relay 62 is connected to the second terminal of the bus capacitor 5.

[0031] The main positive relay 61 and main negative relay 62 of this application are switches for the high-voltage circuit, and remain open when pre-charging is not successful. The main negative relay 62 closes before pre-charging to conduct the pre-charging circuit and prevents the high voltage of the battery pack from being directly connected to the bus capacitor 5, which would cause a large current surge; after successful pre-charging, it closes to achieve stable conduction of the high-voltage circuit.

[0032] In step S3, the bidirectional DC-DC converter 3 verifies the pre-charge trigger condition, including: detecting whether the voltage fluctuation amplitude of the target voltage within a preset time is within a preset fluctuation range, and detecting whether the first voltage is greater than a preset voltage. If the voltage fluctuation amplitude of the target voltage does not exceed the preset fluctuation range, and the first voltage is greater than the preset voltage, the bidirectional DC-DC converter 3 determines that the pre-charge trigger condition verification result is passed. If the voltage fluctuation amplitude of the target voltage exceeds the preset fluctuation range, or the first voltage is less than or equal to the preset voltage, the bidirectional DC-DC converter 3 determines that the pre-charge trigger condition verification result is failed, and the bidirectional DC-DC converter 3 enters a standby state, exiting the reverse pre-charge execution.

[0033] The bidirectional DC-DC converter 3 of this application can be a standalone bidirectional DC-DC converter (DCDC) or an on-board power module that integrates a bidirectional DC-DC converter and an on-board charger (OBC).

[0034] This application verifies the pre-charge trigger condition to ensure that the target voltage signal is in a stable state before the bidirectional DC-DC converter 3 starts boosting. If the target voltage fluctuates too much, the bidirectional DC-DC converter 3 will boost the voltage at an unstable value, failing to obtain the specific boost target, which may lead to faults such as insufficient boost, overvoltage, or current surge, damaging the high-voltage circuit components.

[0035] In step S3, the detection target for pre-charge trigger condition verification is the target voltage issued by the battery management module 2, for example, 800V. The bidirectional DC-DC converter 3 detects whether the voltage fluctuation amplitude of the target voltage within a preset time is within a preset fluctuation range. The preset time is, for example, 200ms, or 3 voltage sampling frames. The preset fluctuation range is, for example, ±5V. That is, if the voltage fluctuation amplitude of the 800V target voltage within 200ms is within ±5V, it indicates that the target voltage has no large jump, the target voltage signal is stable, and the boost condition is met. If the verification fails, that is, if the fluctuation amplitude of the 800V target voltage within 200ms exceeds ±5V, or the difference between any two voltage frames exceeds ±5V, then the target voltage jump is abnormal and the boost condition is not met.

[0036] In step S4, the pre-charge process parameters include the pre-charge time and the voltage difference across the main positive relay 61; the battery management module 2 and the bidirectional DC-DC converter 3 acquire the pre-charge process parameters generated by the pre-charge of the bus capacitor 5, and respectively detect the pre-charge process parameters, including: Battery management module 2 obtains the voltage difference across the main positive relay 61, and bidirectional DC-DC converter 3 obtains the pre-charge time. If the pre-charge time is within the preset timeout period and the voltage difference across the main positive relay 61 is less than the preset voltage difference, battery management module 2 determines that the pre-charge process parameters meet the pre-charge completion conditions.

[0037] This application determines whether the pre-charge meets the standard by monitoring pre-charge process parameters, including pre-charge time and voltage difference across the main positive relay 61. The pre-charge time represents the duration for which the bidirectional DC-DC converter 3 continuously charges the bus capacitor 5 after starting the boost pre-charge, and is obtained by real-time timing from the bidirectional DC-DC converter 3.

[0038] The voltage difference across the main positive relay 61 is the difference between the voltage across the bus capacitor 5 and the battery pack voltage. Since the main positive relay 61 is connected in series between the positive terminal of the battery pack and the bus capacitor 5, when it is not closed, the voltage difference across it is equal to the difference between the voltage of the bus capacitor 5 and the battery pack voltage. The voltage difference across the main positive relay 61 is acquired by the battery management module 2.

[0039] The bidirectional DC-DC converter 3 in this application is responsible for acquiring and detecting the precharge time, monitoring whether the charging time exceeds the safe range, and avoiding overheating of the device due to excessively long precharge. The battery management module 2 is used to acquire and detect the voltage difference across the main positive relay 61. Specifically, it can collect the voltage across the main positive relay 61 through a voltage sensor, calculate the difference, and determine whether the voltage of the bus capacitor 5 is close to the battery pack voltage.

[0040] This application requires that the pre-charge process parameters meet the pre-charge completion conditions simultaneously, namely, the pre-charge time is within a preset timeout period and the voltage difference across the main positive relay 61 is less than a preset voltage difference. The preset timeout period is, for example, 6 seconds, and the preset voltage difference is, for example, 15V. That is, the pre-charge time is less than or equal to 6 seconds; and the difference between the voltage of the bus capacitor 5 and the battery pack voltage is less than 15V. At this time, controlling the main positive relay 61 to close effectively prevents large current surges.

[0041] After the main positive relay 61 is closed, reverse pre-charge is completed. The reverse pre-charge status flag reports that pre-charge is complete, and the bidirectional DC-DC converter 3 switches to standby mode.

[0042] In some embodiments, the bidirectional DC-DC converter 3 boosts the first voltage obtained according to the pre-charge current and outputs the target voltage electrical energy to the bus capacitor 5. The bidirectional DC-DC converter 3 further includes: judging in real time whether there is a fault in the boosting process. If there is a fault, the bidirectional DC-DC converter 3 stops boosting and exits the reverse pre-charge execution.

[0043] In some embodiments, the pre-charge current output by the battery management module 4 is 10A to 60A, for example, it can be any one of 10A, 20A, 30A, 40A, 50A, and 60A, or a range of any two. The first voltage output by the battery management module 4 is 9V to 16V, for example, it can be any one of 9V, 10V, 11V, 12V, 13V, 14V, 15V, and 16V, or a range of any two. This application uses the pre-charge current output by the battery management module 4, and the bidirectional DC-DC converter 3 performs constant current boost according to this pre-charge current, which can avoid the large current surge caused by the instantaneous charging of the bus capacitor 5, effectively protecting the high-voltage circuit devices.

[0044] Embodiments of this application also provide a reverse pre-charge control system, such as... Figure 3 As shown, it includes: Vehicle controller 1 is used to output high voltage commands.

[0045] Battery management module 2 is connected to vehicle controller 1 via CAN bus. It is used to receive high voltage command, perform pre-detection on main relay according to high voltage command, and output pre-charge command signal to bidirectional DC-DC converter 3 if the pre-detection is successful.

[0046] Battery management module 4 is used to output pre-charge current to bidirectional DC-DC converter 3 and provide the first voltage.

[0047] The bidirectional DC-DC converter 3 is used to verify the precharge trigger condition. If the verification is successful, the first voltage obtained is boosted to the target voltage according to the precharge current, and the target voltage is output to the bus capacitor 5 to perform precharge. Battery management module 2 and bidirectional DC-DC converter 3 are also used to acquire and detect the pre-charge process parameters generated by the pre-charge of bus capacitor 5, and control the main relay to close when the pre-charge process parameters meet the pre-charge completion conditions.

[0048] This application establishes a controllable connection between the battery pack and the bus capacitor 5 using a main positive relay 61 and a main negative relay 62. The positive output terminal of the battery pack is connected to the first terminal of the main positive relay 61, and the second terminal of the main positive relay 61 is connected to the first terminal of the bus capacitor 5. The negative output terminal of the battery pack is connected to the first terminal of the main negative relay 62, and the second terminal of the main negative relay 62 is connected to the second terminal of the bus capacitor 5.

[0049] After receiving the high-voltage command, the battery management module 2 checks whether the main negative relay 62 is stuck. If the pre-detection passes, it first controls the main negative relay 62 to close, and then outputs a pre-charge command signal to the bidirectional DC-DC converter 3. After the bidirectional DC-DC converter 3 performs pre-charge, the battery management module 2 obtains the voltage difference across the main positive relay 61. The bidirectional DC-DC converter 3 obtains the pre-charge time. If the pre-charge time is within the preset timeout period and the voltage difference across the main positive relay 61 is less than the preset voltage difference, it controls the main positive relay 61 to close, thus completing the pre-charge.

[0050] This application sends a high-voltage command to the vehicle controller 1, the battery management module 2 outputs a pre-charge command signal to the bidirectional DC-DC converter 3, and the battery management module 4 outputs a pre-charge current to the bidirectional DC-DC converter 3. By utilizing the bidirectional working principle of the bidirectional DC-DC converter 3, the low-voltage electrical energy output by the battery is boosted to the target high voltage to complete the pre-charge. There is no need to set up special devices such as pre-charge relays and pre-charge resistors, which simplifies the hardware layout of the vehicle's high-voltage system.

[0051] The foregoing has provided a detailed description of a reverse pre-charge control system and method provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A reverse pre-charge control method, characterized in that, Includes the following steps: The vehicle controller outputs a high-voltage command to the battery management module, and the battery management module performs a pre-detection on the main relay according to the high-voltage command. If the pre-detection passes, the battery management module outputs a pre-charge command signal to the bidirectional DC-DC converter, and the battery management module outputs a pre-charge current to the bidirectional DC-DC converter. The bidirectional DC-DC converter verifies the precharge trigger condition. If the precharge trigger condition is verified, the bidirectional DC-DC converter boosts the first voltage obtained by the precharge current to the target voltage and outputs the target voltage to the bus capacitor to perform precharge. The battery management module and the bidirectional DC-DC converter acquire the pre-charge process parameters generated by the pre-charge of the bus capacitor, and detect the pre-charge process parameters respectively. When the pre-charge process parameters meet the pre-charge completion conditions, the main relay is closed to complete the pre-charge.

2. The reverse pre-charge control method according to claim 1, characterized in that, The main relay includes a main positive relay and a main negative relay; the battery management module performs a pre-detection on the main relay according to the high-voltage command, including: the battery management module detects whether the main negative relay is stuck; if the main negative relay is stuck, the battery management module determines that the pre-detection result is failed and exits the reverse pre-charging process; if the main negative relay is not stuck, the battery management module determines that the pre-detection result is passed.

3. The reverse pre-charge control method according to claim 2, characterized in that, The reverse precharge control method further includes: if the pre-detection passes, the battery management module closes the main negative relay.

4. The reverse pre-charge control method according to claim 2, characterized in that, The battery management module includes a battery pack. The positive terminal of the battery pack is connected to the first terminal of the bus capacitor through the main positive relay, and the negative terminal of the battery pack is connected to the second terminal of the bus capacitor through the main negative relay. The precharge command signal includes a precharge enable signal and the target voltage, where the target voltage is the real-time voltage of the battery pack.

5. The reverse pre-charge control method according to claim 1, characterized in that, The bidirectional DC-DC converter verifies the precharge trigger condition by: detecting whether the voltage fluctuation amplitude of the target voltage within a preset time is within a preset fluctuation range, and detecting whether the first voltage is greater than a preset voltage; if the voltage fluctuation amplitude of the target voltage does not exceed the preset fluctuation range, and the first voltage is greater than the preset voltage, the bidirectional DC-DC converter determines that the precharge trigger condition verification result is passed.

6. The reverse pre-charge control method according to claim 2, characterized in that, The pre-charge process parameters include the pre-charge time and the voltage difference across the main positive relay; the battery management module and the bidirectional DC-DC converter acquire the pre-charge process parameters generated by the bus capacitor pre-charge, and respectively detect the pre-charge process parameters, including: The battery management module obtains the voltage difference across the main positive relay, and the bidirectional DC-DC converter obtains the pre-charge time. If the pre-charge time is within a preset timeout period and the voltage difference across the main positive relay is less than a preset voltage difference, the battery management module determines that the pre-charge process parameters meet the pre-charge completion conditions.

7. The reverse pre-charge control method according to claim 1, characterized in that, The bidirectional DC-DC converter boosts the first voltage obtained from the pre-charge current and outputs the target voltage to the bus capacitor. It also includes: the bidirectional DC-DC converter judging in real time whether there is a fault in the boosting process. If there is a fault, the bidirectional DC-DC converter stops boosting and exits the reverse pre-charge execution.

8. The reverse pre-charge control method according to claim 1, characterized in that, The first voltage output by the battery management module is 9V~16V.

9. The reverse pre-charge control method according to claim 1, characterized in that, The pre-charging current output by the battery management module is 10A~60A.

10. A reverse pre-charge control system, characterized in that, include: The vehicle controller is used to output high-voltage commands; The battery management module is used to receive the high voltage command, perform pre-detection on the main relay according to the high voltage command, and output a pre-charge command signal to the bidirectional DC-DC converter if the pre-detection is successful. The battery management module is used to output a pre-charge current to the bidirectional DC-DC converter and provide a first voltage; A bidirectional DC-DC converter is used to verify the precharge trigger conditions. If the verification is successful, the first voltage obtained is boosted to the target voltage according to the precharge current, and the electrical energy of the target voltage is output to the bus capacitor to perform precharge. The battery management module and the bidirectional DC-DC converter are also used to acquire and detect the pre-charge process parameters generated by the pre-charge of the bus capacitor, and control the main relay to close when the pre-charge process parameters meet the pre-charge completion conditions.

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