Railway tractor double-side independent isolation type double-path alternating current charging system and control method thereof

Abstract

The application provides a double-side independent isolation type double-path alternating current charging system of a rail tractor and a control method thereof. The system comprises double-side CCS2 alternating current charging interfaces, two sets of EVCCs, two on-board chargers, two all-in-one controllers, a BMS, a VCU and a high-voltage power distribution unit of a whole vehicle. Two charging circuits are configured with independent hard-wire wake-up circuits with electrical isolation, and protection devices are arranged in the high-voltage branches. The two chargers are connected to the same vehicle CAN bus by using unique and non-repeated CAN message IDs, and the all-in-one controllers control the insulation detection and high-voltage on-off of the corresponding branches. The application realizes the wake-up of the corresponding charger by single-side plug-in, and the isolation of the fault branch and the shielding of the fault message when single-path fault occurs, so that the other charging circuit can still work normally without the need of vehicle shutdown for maintenance. The application solves the problems of poor station adaptation and vehicle charging failure caused by single-point fault in the traditional scheme, and improves the energy supplement redundancy reliability and operation and maintenance economy of the rail tractor.

Description

Technical Field

[0001] This invention relates to the field of electric rail traction vehicle charging control technology, and particularly to a dual-circuit AC charging system for rail traction vehicles with independent isolation on both sides and its control method. Background Technology

[0002] The electrification of rail traction vehicles and shunting locomotives within the yard is gradually becoming widespread, and AC slow charging has become the mainstream method for daily power replenishment of rail vehicles. Most existing rail traction vehicle charging systems adopt a single-side single-interface + single-path on-board charger architecture; a few dual-path charging solutions adopt a simple parallel design with common wake-up and common communication, without optimization for the operating conditions of rail vehicles.

[0003] Existing technological shortcomings: 1) Poor site compatibility: The charging interface is only set on one side. In scenarios where the charging pile is placed on the left or right, the vehicle needs to turn around or use an extension cable, resulting in low operation efficiency. 2) Fault-free isolation: Dual-path common bus and common wake-up scheme. Hardware failure or communication failure of a single charger, abnormal message pollution of the vehicle's CAN bus, interference with BMS, causing the other charger to also fail, a single point of failure causes the entire vehicle's charging to be paralyzed; rail traction vehicles are industrial operation vehicles with high requirements for charging redundancy reliability, which the existing solution cannot meet. 3) Poor working condition matching: The dual-circuit charging solution for passenger vehicles was directly transplanted to the on-site rail traction vehicle without considering the industrial scenario requirements of flexible parking, convenient operation and maintenance, and high redundancy. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a dual-circuit AC charging system and its control method for a rail traction vehicle with independent isolation on both sides.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a dual-circuit AC charging system for a rail traction vehicle with independent isolation on both sides, including a power battery pack (Battery), a battery management system (BMS), a vehicle controller (VCU), and a vehicle high-voltage power distribution unit (BatteryPDU). The system also includes a 1#CCS2 AC charging interface, a 2#CCS2 AC charging interface, a first charging communication module (EVCC1), a second charging communication module (EVCC2), a first on-board charger (OBC1), a second on-board charger (OBC2), a 1# multi-function controller, and a 2# multi-function controller. The 1#CCS2 AC charging interface is paired with the first charging communication module EVCC1; the first charging communication module EVCC1 is connected to the wake-up pin of the first on-board charger OBC1 through a first independent hard-wired wake-up circuit; the 2#CCS2 AC charging interface is paired with the second charging communication module EVCC2; the second charging communication module EVCC2 is connected to the wake-up pin of the second on-board charger OBC2 through a second independent hard-wired wake-up circuit; the two hard-wired wake-up circuits are completely electrically isolated; The first on-board charger OBC1 has its AC input terminal connected to the 1#CCS2 AC charging interface; the second on-board charger OBC2 has its AC input terminal connected to the 2#CCS2 AC charging interface; the first on-board charger OBC1's DC output is connected to the first independent high-voltage branch of the vehicle's high-voltage power distribution unit (BatteryPDU); the second on-board charger OBC2's DC output is connected to the second independent high-voltage branch of the vehicle's high-voltage power distribution unit (BatteryPDU); the first and second independent high-voltage branches are respectively equipped with independent fuses and contactor protection devices. The first on-board charger OBC1 and the second on-board charger OBC2 are connected to the same vehicle CAN bus; the first on-board charger OBC1 is configured with a first unique CAN message ID; the second on-board charger OBC2 is configured with a second unique CAN message ID, and the two message IDs are not repeated; the battery management system (BMS) distinguishes the two chargers through different message IDs. The first multi-function controller controls the insulation detection and high-voltage switching of the first independent high-voltage branch; the second multi-function controller controls the insulation detection and high-voltage switching of the second independent high-voltage branch; the first multi-function controller and the second multi-function controller interact with the status of the battery management system (BMS) and the vehicle control unit (VCU), respectively.

[0006] Preferably, the DC bus of the first independent high-voltage branch and the second independent high-voltage branch of the vehicle high-voltage power distribution unit (BatteryPDU) are combined to the high-voltage bus of the power battery pack; the two AC inputs are physically isolated from each other, and the two DC branches are controlled to be switched on and off respectively.

[0007] Preferably, the first charging communication module EVCC1 and the second charging communication module EVCC2 are electrically connected to the connection confirmation signal pins of the corresponding AC charging interfaces 1#CCS2 and 2#CCS2 on the respective sides; the first charging communication module EVCC1 and the second charging communication module EVCC2 are used to collect the connection confirmation signal of the charging gun, and selectively output a wake-up signal to the corresponding on-board charger based on the connection confirmation signal, so that only the on-board charger on the plug-in side is triggered and woken up.

[0008] Preferably, the battery management system (BMS) is configured to filter messages for the two on-board chargers based on the CAN message ID; when a charger fault message corresponding to a certain message ID is identified, the BMS blocks the fault message of that message ID, only issues a disconnect command to the charging branch corresponding to the fault, and retains the charger communication interaction channel corresponding to the other message ID without disconnecting it.

[0009] The control method for a dual-circuit AC charging system with independent isolation on both sides of a rail traction vehicle includes the following steps: S1. Activate by inserting the gun: When the charging gun is plugged into the charging port on either side, the EVCC on the same side detects the CC connection confirmation signal and outputs a wake-up level, waking up only the corresponding side OBC, while the other side OBC remains in sleep mode. S2, Handshake Self-Check: The awakened OBC sends a handshake message to the BMS via its own unique CAN message ID; the BMS verifies the device identity and branch insulation status; if the verification is successful, the BMS outputs the EVReady=Permit charging enable signal; the CP state switches to STATE_C, and the S2 switch is closed. S3, High voltage conduction: The VCU sends a power distribution command to the vehicle's high-voltage power distribution unit, and the corresponding branch contactor closes to establish a high-voltage circuit between the charger and the power battery. S4, Charging Execution: The BMS sends charging parameters based on the battery SOC and battery temperature; the OBC performs constant current-constant voltage charging. S5. Fault Degradation Handling: When a fault is reported by a certain OBC, the BMS blocks the ID message and the VCU disconnects the contactor of that branch; the charging circuit on the other side continues to operate normally. S6, Stop and hibernate: When the battery is fully charged or a stop command is received, the BMS issues a stop command; the OBC shuts off the power output; the branch contactor disconnects; the CP returns to STATE_B, the S2 switch opens, and the module enters sleep mode.

[0010] Preferably, constant current-constant voltage charging control is used during the charging execution phase, and the formulas for the charging output voltage and current are as follows: ; ; In the formula, To provide real-time output power for the on-board charger; 1. Power battery terminal voltage; 2. Charging output current; Rated power for a single OBC; Set the charging current for the constant current stage; This is the constant voltage conversion threshold voltage; The battery is in its state of charge. Battery temperature; when When, constant current charging is performed; when At this time, it enters constant voltage charging, and the charging current varies with the battery voltage. The battery temperature is dynamically adjusted downwards.

[0011] Preferably, the enabling and fault reporting of the charging circuits meet the following logic: the enabling of the first on-board charger requires that the left charging port plug confirmation signal is valid and the first on-board charger is fault-free; the enabling of the second on-board charger requires that the right charging port plug confirmation signal is valid and the second on-board charger is fault-free; when only one on-board charger fails, only the fault of that branch is reported, and the enabling of the other charger is not cut off; only when both on-board chargers fail simultaneously is the overall vehicle charging fault reporting triggered.

[0012] The Boolean logic formula for fault isolation is as follows: In the formula, For the #1 CCS2 AC charging port; For the #2 CCS2 AC charging port; This is the fault flag bit for the first on-board charger OBC1. This is the fault flag bit for the second on-board charger OBC1; Enable the first on-board charger OBC1 to work; Enable the second on-board charger OBC1 to work; For reporting vehicle bus faults; cross-domain When there is only a single-path fault, only the corresponding branch fault is reported. The enable of the faulty branch is cleared, and the enable of the other branch is not affected. This will not trigger the complete locking of the vehicle charging function.

[0013] Ideally, when a single-sided OBC fails, the faulty branch performs the following actions: disconnecting the wake-up hard wire signal, disconnecting the high-voltage contactor, and blocking the reception of CAN messages for that ID. After the fault is resolved, the charging interface on the other side can be used directly to complete the charging without the need for the entire vehicle to be shut down for maintenance.

[0014] Compared with existing technologies, the beneficial effects of this invention are as follows: Addressing the shortcomings of existing technologies in terms of adaptability to various station scenarios, this invention adopts a dual-sided independent charging interface layout for vehicles, compatible with diverse deployment scenarios such as left- or right-side charging pile placement. During operation, there is no need to reverse the vehicle's parking direction or connect extension cables for charging, effectively simplifying on-site operation procedures. This matches the flexible parking characteristics of rail traction vehicles, significantly improving the convenience of charging operations and the overall operational efficiency of the station. Furthermore, addressing the lack of fault isolation capabilities in traditional dual-path charging architectures, this invention constructs a dual-layer isolation mechanism using hardware wake-up and CAN communication protocols. The two chargers are configured with independent hard-wired wake-up circuits and differentiated unique CAN message IDs. When a single charger experiences a hardware or communication failure, the fault signal is confined to its own branch, preventing interference with the battery management system and avoiding the failure of intact charging circuits. This achieves degraded charging under single-point fault conditions, fully meeting the high reliability and high redundancy requirements of rail traction vehicles in industrial operations.

[0015] This invention addresses the issue of low operational condition matching in existing charging solutions. The entire charging architecture is custom-developed to meet the operational needs of on-site rail traction vehicles, differing from directly transplanting dual-circuit charging solutions for passenger cars. It fully considers the actual operating conditions of variable vehicle parking locations, high reliability requirements for energy replenishment, and unique on-site maintenance conditions. Furthermore, the hardware specifications of the two on-board chargers are consistent, spare parts are universal, and individual equipment failures can be replaced without modifying the overall vehicle power distribution architecture. In the event of a failure, the system can directly switch to the other charging interface to continue replenishing energy without requiring a complete vehicle shutdown for maintenance, reducing equipment maintenance costs and shortening vehicle downtime. This results in excellent engineering practicality and economical operation and maintenance. Attached Figure Description

[0016] Figure 1 Hardware architecture topology diagram of a dual-path AC charging system with independent fault isolation on both sides for a rail traction vehicle; In the diagram: Battery - Power Battery Pack; Battery PDU - Vehicle High Voltage Power Distribution Unit; BMS - Battery Management System; VCU - Vehicle Controller; EVCC1 - First Charging Communication Module; EVCC2 - Second Charging Communication Module; OBC1 - First On-Board Charger; OBC2 - Second On-Board Charger; 1#CCS2 - 1# AC Charging Interface; 2#CCS2 - 2# AC Charging Interface; 1#All-in-One - 1# All-in-One Controller; 2#All-in-One - 2# All-in-One Controller; VCU - Vehicle Controller; Thin blue line - LV harness (low voltage); Dashed line - CAN Communication; Thick yellow line - HV harness (high voltage). Detailed Implementation

[0017] To provide a further understanding of the purpose, structure, features, and functions of the present invention, detailed descriptions are provided below with reference to specific embodiments.

[0018] Please refer to the reference. Figure 1 This invention provides a dual-circuit AC charging system with independent isolation on both sides for a rail traction vehicle and its control method.

[0019] Example 1: Complete workflow of normal single-channel charging (taking left-side plug-in charging as an example, the charging logic on the right side is completely symmetrical).

[0020] S1. Gun Insertion Wake-up: When the AC charging gun is inserted into the AC charging interface 1#CCS2 on the left side of the vehicle, the first charging communication module EVCC1 detects the CC connection confirmation signal and immediately outputs a 12V hardware wake-up level, waking up only the first on-board charger OBC1 to enter the power-on initialization standby state; at this time, the second charging communication module EVCC2 on the right does not receive the gun insertion signal, and the second on-board charger OBC2 remains in a power-off sleep state throughout the process, without any power-on or message sending behavior, realizing single-side gun insertion and single-side wake-up.

[0021] At this time, the initial state of the charging CAN link is CP=STATE_B, S2 switch=Open, the EVReady state of the battery management system (BMS) is set to Prepare, and the physical connection identification and low-voltage circuit power-on are completed.

[0022] S2. Handshake Self-Test: After completing power-on initialization, the first on-board charger (OBC1) sends a handshake message to the Battery Management System (BMS) using its proprietary CAN message ID=0x18FF50E5. The BMS verifies the charger's identity and receives the branch insulation test results reported by the #1 multi-function controller, completing branch fault troubleshooting. After all verifications pass, the BMS transitions from the EVReady state to Permit, outputting a charging permission command; the charging link CP state switches from STATE_B to STATE_C, and the S2 switch switches from Open to Closed, confirming entry into ACCharging mode and completing the full-loop readiness verification before charging.

[0023] S3, High Voltage Conduction: After receiving the charging permission signal from the Battery Management System (BMS), the Vehicle Controller (VCU) sends a power distribution command to the Vehicle High Voltage Distribution Unit (BatteryPDU) to control the closing of the high voltage contactor inside the first independent high voltage branch, thus establishing a high voltage power transmission path between the first on-board charger (OBC1) and the power battery pack.

[0024] S4. Charging Execution: The Battery Management System (BMS) collects real-time SOC, battery temperature, and individual cell voltage information of the power battery, and sends charging voltage and charging current control parameters to the first on-board charger (OBC1) with message ID=0x18FF50E5. The first on-board charger (OBC1) executes AC-DC power conversion according to constant current-constant voltage control logic, and reports its own output voltage, output current, module temperature, and fault status in real time. The charging process strictly follows the power, current, and voltage constraint formulas: constant current charging is executed when the battery voltage is below the constant voltage conversion threshold; when the battery voltage reaches the constant voltage conversion threshold, it automatically switches to constant voltage mode, and the charging current is dynamically adjusted according to the battery voltage, SOC, and battery temperature until the battery is fully charged.

[0025] S5. Shutdown and Hibernation: When the power battery SOC reaches the full charge threshold, or a manual stop charging command is received, the Battery Management System (BMS) sends a shutdown command to the first on-board charger (OBC1); the first on-board charger (OBC1) shuts off the AC-DC power output. The Vehicle Control Unit (VCU) sends a command to disconnect the first branch high-voltage contactor, cutting off the high-voltage circuit; the charging link CP state returns to STATE_B, and the S2 switch resets to the Open state; subsequently, the first charging communication module (EVCC1) and the first on-board charger (OBC1) enter hibernation sequentially, and the entire charging circuit returns to standby state.

[0026] If the charging gun is plugged into the AC charging port 2#CCS2 on the right side, the entire process logic is completely symmetrical with that on the left side. Only the working objects are switched to the second charging communication module EVCC2, the second on-board charger OBC2, and the 2# multi-in-one controller. The entire charging circuit on the left side remains in sleep mode throughout the process, with no electrical or communication coupling.

[0027] Example 2: Single-path fault degradation operation condition (the core verification condition of this example).

[0028] If a hardware failure or communication anomaly occurs in the first on-board charger (OBC1) during the charging process, the first on-board charger (OBC1) will report a fault message to the vehicle's CAN bus via ID=0x18FF50E5.

[0029] The BMS identifies the fault information corresponding to the unique message ID, performs message filtering, and blocks abnormal messages from that ID to prevent them from interfering with the BMS itself and other devices on the bus. Simultaneously, the BMS sends a command to the VCU, which in turn controls the #1 multi-in-one controller to disconnect the high-voltage contactor of the first branch, cutting off the high-voltage output of the faulty branch. The first charging communication module EVCC1 disconnects the hard-wire wake-up signal of the first on-board charger OBC1, locking the faulty branch.

[0030] According to the fault Boolean logic in this embodiment, if only the first on-board charger OBC1 fails, only a partial fault flag for that branch will be reported; a total vehicle charging fault will not be reported, and the charging function of the other branch will not be blocked. In this case, the operator does not need to inspect the faulty circuit; they can directly plug the charging gun into the AC charging port #2 (CCS2) on the right side of the vehicle. The system will automatically wake up the second on-board charger OBC2, execute the complete right-side charging process, and continue to recharge the power battery. The vehicle does not need to be stopped for maintenance. Only when both the first and second on-board chargers OBC1 and OBC2 fail simultaneously will the system report a total vehicle charging fault and prohibit charging operations.

[0031] This embodiment completes the real-vehicle CAN message acquisition test, collecting complete message sequences for both the left and right independent charging conditions. The message results confirm two core design effects: First, the hard-wired wake-up isolation is effective; only the charger on the plugged-in side is woken up, while the charger on the unplugged side does not output any messages, thus preventing false wake-ups and fault propagation across branches at the hardware level. Second, the differential CAN-ID communication isolation is effective; the two chargers use independent message IDs, allowing the Battery Management System (BMS) to accurately distinguish between the two charging branches. A fault message generated by a single branch is limited to its own ID channel and will not pollute the vehicle's CAN bus, ensuring that the communication between the other charger and the BMS is not interfered with.

[0032] In this embodiment, the hardware models and component parameters of the two on-board chargers are completely identical, and spare parts can be directly interchanged. When the hardware of one charger is permanently damaged, the faulty charger can be disassembled and replaced separately without modifying the high-voltage power distribution architecture of the entire vehicle. The maintenance operation is simple and the operation and maintenance costs are low.

[0033] Example 3: This example describes a dual-circuit AC charging system with independent isolation on both sides, suitable for daily AC slow-charging operations of shunting and in-yard transfer rail traction vehicles. The vehicle is equipped with a 619V lithium iron phosphate battery pack, which matches the power requirements of the high-power operation of the rail traction vehicle. The vehicle is equipped with two sets of multi-in-one controllers with completely identical hardware parameters, namely, multi-in-one controller #1 and multi-in-one controller #2. Each multi-in-one controller integrates branch insulation detection, high-voltage contactor drive, and circuit protection functions. Each multi-in-one controller is connected to an external 22kW on-board charger (OBC), namely, on-board charger OBC1 and on-board charger OBC2.

[0034] One CCS2 AC charging interface is installed on each of the left and right sides of the vehicle body, and is designated as 1#CCS2 (AC charging interface 1) and 2#CCS2 (AC charging interface 2) respectively. Each CCS2 charging interface is equipped with an independent charging communication module EVCC. The left interface is matched with the first charging communication module EVCC1, and the right interface is matched with the second charging communication module EVCC2.

[0035] The high-voltage bus of the power battery pack is connected to the vehicle's high-voltage power distribution unit (PDU), and the battery management system (BMS) coordinates the distribution of high-voltage power throughout the vehicle. The DC output of the first on-board charger (OBC1) is connected to the first independent high-voltage branch within the vehicle's high-voltage power distribution unit; the DC output of the second on-board charger (OBC2) is connected to the second independent high-voltage branch within the same unit. These two high-voltage branches are independent of each other, each equipped with a dedicated fuse and high-voltage contactor for protection. The outputs of the two independent high-voltage branches ultimately converge to the common high-voltage bus of the power battery pack. The AC input of the first on-board charger (OBC1) is directly connected to the left-side #1 CCS2 AC charging interface, and the AC input of the second on-board charger (OBC2) is directly connected to the right-side #2 CCS2 AC charging interface. The two AC input circuits are physically completely isolated, with no electrical coupling. A short circuit or leakage in one AC circuit will not be conducted to the other.

[0036] The first charging communication module EVCC1 is electrically connected to the CC connection confirmation pin of the left-side 1#CCS2 AC charging interface. The wake-up output of the first charging communication module EVCC1 is directly connected to the hardware wake-up pin of the first on-board charger OBC1 via a dedicated, independent low-voltage hard wire. The second charging communication module EVCC2 is electrically connected to the CC connection confirmation pin of the right-side 2#CCS2 AC charging interface. The wake-up output of the second charging communication module EVCC2 is connected to the hardware wake-up pin of the second on-board charger OBC2 via another dedicated, independent low-voltage hard wire. The two wake-up hard wire loops are independent and electrically isolated from each other, and there is no common line or common wake-up source. The wake-up level signal of one loop will not trigger any action of the other charger.

[0037] The first on-board charger OBC1 and the second on-board charger OBC2 are both connected to the same CAN bus of the vehicle, but they are configured with unique message IDs that do not overlap. In this embodiment, the message ID of the first on-board charger OBC1 is set to 0x18FF50E5, and the message ID of the second on-board charger OBC2 is set to 0x18FF50E6.

[0038] The Battery Management System (BMS) distinguishes between the two on-board chargers using message IDs, enabling separate message reception, filtering, and command issuance for each device. Controller #1 is responsible for insulation detection and contactor on / off control of the first high-voltage branch; Controller #2 is responsible for insulation detection and contactor on / off control of the second high-voltage branch. Both controllers simultaneously interact with the BMS and the Vehicle Control Unit (VCU) via CAN, reporting the insulation status, contactor status, and fault information of their respective charging branches in real time.

[0039] The present invention has been described in the above-described embodiments; however, these embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, any modifications and refinements made without departing from the spirit and scope of the present invention are within the scope of patent protection of the present invention.

Claims

1. A dual-circuit AC charging system for a rail traction vehicle with independent isolation on both sides, comprising a power battery pack (Battery), a battery management system (BMS), a vehicle controller (VCU), and a vehicle high-voltage power distribution unit (BatteryPDU), characterized in that: The system also includes a 1#CCS2 AC charging interface, a 2#CCS2 AC charging interface, a first charging communication module EVCC1, a second charging communication module EVCC2, a first on-board charger OBC1, a second on-board charger OBC2, a 1# multi-function controller, and a 2# multi-function controller. The 1#CCS2 AC charging interface is paired with the first charging communication module EVCC1; the first charging communication module EVCC1 is connected to the wake-up pin of the first on-board charger OBC1 through a first independent hard-wired wake-up circuit; the 2#CCS2 AC charging interface is paired with the second charging communication module EVCC2; the second charging communication module EVCC2 is connected to the wake-up pin of the second on-board charger OBC2 through a second independent hard-wired wake-up circuit; the two hard-wired wake-up circuits are completely electrically isolated; The first on-board charger OBC1 has its AC input terminal connected to the 1#CCS2 AC charging interface; the second on-board charger OBC2 has its AC input terminal connected to the 2#CCS2 AC charging interface; the first on-board charger OBC1's DC output is connected to the first independent high-voltage branch of the vehicle's high-voltage power distribution unit (BatteryPDU); the second on-board charger OBC2's DC output is connected to the second independent high-voltage branch of the vehicle's high-voltage power distribution unit (BatteryPDU); the first and second independent high-voltage branches are respectively equipped with independent fuses and contactor protection devices. The first on-board charger OBC1 and the second on-board charger OBC2 are connected to the same vehicle CAN bus; the first on-board charger OBC1 is configured with a first unique CAN message ID; the second on-board charger OBC2 is configured with a second unique CAN message ID, and the two message IDs are not repeated; the battery management system (BMS) distinguishes the two chargers through different message IDs. The first multi-function controller controls the insulation detection and high-voltage switching of the first independent high-voltage branch; the second multi-function controller controls the insulation detection and high-voltage switching of the second independent high-voltage branch; the first multi-function controller and the second multi-function controller interact with the status of the battery management system (BMS) and the vehicle control unit (VCU), respectively.

2. The dual-circuit AC charging system for rail traction vehicles with independent isolation on both sides as described in claim 1, characterized in that: The first independent high-voltage branch and the second independent high-voltage branch DC bus of the vehicle high-voltage power distribution unit BatteryPDU are combined to the high-voltage bus of the power battery pack; the two AC inputs are physically isolated from each other, and the two DC branches are controlled to be switched on and off respectively.

3. The dual-circuit AC charging system for rail traction vehicles with independent isolation on both sides as described in claim 1, characterized in that: The first charging communication module EVCC1 and the second charging communication module EVCC2 are electrically connected to the connection confirmation signal pins of the corresponding AC charging interfaces 1#CCS2 and 2#CCS2 on the respective sides. The first charging communication module EVCC1 and the second charging communication module EVCC2 are used to collect the connection confirmation signal of the charging gun and selectively output a wake-up signal to the corresponding on-board charger based on the connection confirmation signal, so that only the on-board charger on the plug-in side is triggered and woken up.

4. The dual-circuit AC charging system for rail traction vehicles with independent isolation on both sides as described in claim 1, characterized in that: The battery management system (BMS) is configured to filter messages from the two on-board chargers based on the CAN message ID. When a charger fault message corresponding to a certain message ID is detected, the BMS blocks the fault message of that message ID and only issues a disconnect command to the charging branch corresponding to the fault, while keeping the charger communication interaction channel corresponding to the other message ID intact.

5. The control method for the dual-circuit AC charging system of a rail traction vehicle with independent isolation on both sides according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Activate by inserting the gun: When the charging gun is plugged into the charging port on either side, the EVCC on the same side detects the CC connection confirmation signal and outputs a wake-up level, waking up only the corresponding side OBC, while the other side OBC remains in sleep mode. S2, Handshake Self-Check: The awakened OBC sends a handshake message to the BMS via its own unique CAN message ID; the BMS verifies the device identity and branch insulation status; if the verification is successful, the BMS outputs the EVReady=Permit charging enable signal; the CP state switches to STATE_C, and the S2 switch is closed. S3, High voltage conduction: The VCU sends a power distribution command to the vehicle's high-voltage power distribution unit, and the corresponding branch contactor closes to establish a high-voltage circuit between the charger and the power battery. S4, Charging Execution: The BMS sends charging parameters based on the battery SOC and battery temperature; the OBC performs constant current-constant voltage charging. S5. Fault Degradation Handling: When a fault is reported by a certain OBC, the BMS blocks the ID message and the VCU disconnects the contactor of that branch; the charging circuit on the other side continues to operate normally. S6, Stop and hibernate: When the battery is fully charged or a stop command is received, the BMS issues a stop command; the OBC shuts off the power output; the branch contactor disconnects; the CP returns to STATE_B, the S2 switch opens, and the module enters sleep mode.

6. The control method for the dual-circuit AC charging system of a rail traction vehicle with independent isolation on both sides as described in claim 5, characterized in that: The charging execution phase employs constant current-constant voltage charging control, and the formulas for the charging output voltage and current are as follows: ; ； In the formula, To provide real-time output power for the on-board charger; This refers to the terminal voltage of the power battery. Output current for charging; Rated power for a single OBC; Set the charging current for the constant current stage; This is the constant voltage conversion threshold voltage; Battery state of charge; battery temperature; when When the current is constant, constant current charging is performed; when the current is constant, constant voltage charging is entered, and the charging current varies with the battery voltage. The battery temperature is dynamically adjusted downwards.

7. The control method for the dual-circuit AC charging system of a rail traction vehicle with independent isolation on both sides as described in claim 6, characterized in that: The enabling and fault reporting of the charging circuits follow these logics: Enabling the first on-board charger requires both a valid confirmation signal from the left charging port plug and no fault in the first on-board charger; enabling the second on-board charger requires both a valid confirmation signal from the right charging port plug and no fault in the second on-board charger; when only one on-board charger fails, only that branch's fault is reported, and the other charger's enabling is not disabled; only when both on-board chargers fail simultaneously is a vehicle-wide charging fault reporting triggered.

8. The control method for the dual-circuit AC charging system of a rail traction vehicle with independent isolation on both sides as described in claim 5, characterized in that: When a single-sided OBC fails, the faulty branch will execute the following: cut off the wake-up hard wire signal, disconnect the high-voltage contactor, and block the reception of CAN messages for that ID. After the fault is resolved, the charging interface on the other side can be used directly to complete the power replenishment without the need for the entire vehicle to be shut down for maintenance.

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