SOC (system on chip) self-calibration method and system of extended-range passenger car BMS (battery management system)

Abstract

The invention provides an SOC (system on chip) self-calibration method and system of a BMS (battery management system) of an extended-range passenger car, relates to the technical field of automobile battery management systems, and solves the technical problems of inaccurate SOC and virtual power caused by the fact that an existing extended-range hybrid city passenger car does not perform SOC calibration work. The method comprises the steps that when a vehicle VCU meets a preset condition, an SOC calibration starting instruction is sent to a range extender; the range extender sends a confirmation instruction to the BMS after self-inspection; the BMS enters a calibration state after self-inspection, and sends a maximum allowable charging current value to the range extender in real time; the range extender controls the power generation unit to charge the power battery pack accordingly; the BMS monitors the charging state, SOC calibration is completed when the full charging condition is met, and an exit instruction is sent to the range extender; and the range extender stops generating power, and the whole vehicle exits the calibration mode. The method is used in the regular full-charge SOC calibration process of the extended-range hybrid bus.

Description

Technical Field

[0001] This application relates to the field of automotive battery management system technology, and in particular to a SOC self-calibration method and system for a range-extended bus BMS system. Background Technology

[0002] In existing technologies, the initial correction of SOC is made using the vehicle's own driving conditions. This is estimated by the voltage-current relationship under long-term coasting or specific loads. Specifically, during vehicle operation, the battery is captured in a specific state of rest or low-current load, its open-circuit voltage is read, and compared with a preset SOC-OCV curve to make a small correction to the SOC. However, the above solution is only applicable when the battery is in a specific rest or steady-state condition, and cannot be used in scenarios where the battery needs to be fully charged systematically and periodically to correct the ampere-hour integral error and to balance the battery pack. Throughout the entire lifecycle of a range-extended hybrid bus, battery consistency gradually deteriorates. The inherent flat voltage plateau characteristic of lithium iron phosphate batteries, which only allows for fragmented OCV correction during operation, still fails to completely resolve the issues of long-term SOC drift and widening volume differences between cells. Since the OCV in the plateau region is sensitive to temperature and polarization, fragmented correction may lead to amplified errors if it is not allowed to settle sufficiently. Therefore, designing a calibration process that can be actively, controllably, and periodically triggered and executed, similar to an external full charge, to fundamentally maintain the long-term estimation accuracy of the BMS and the health of the battery pack, has become an urgent technical problem to be solved. Summary of the Invention

[0003] This application provides a method and system for SOC self-calibration of a range-extended electric vehicle (REEV) bus BMS system, relating to the field of automotive battery management system technology. It solves the technical problems of inaccurate SOC and virtual charge in existing range-extended hybrid city buses due to the lack of SOC (State of Charge) calibration, and the limitations imposed on customer operations by traditional calibration methods that rely on external charging piles and on-board charging sockets. This method achieves on-board full-charge SOC self-calibration of the power battery pack through the coordinated cooperation of vehicle VCU (Vehicle Control Unit)-triggered calibration, controlled power generation from the range extender, and real-time current limiting and full-charge determination by the BMS (Battery Management System). Periodic calibration can be completed without external charging equipment, eliminating the requirement for on-board charging sockets and charging piles. This application is applicable to the scenario of periodic full-charge calibration of the power battery SOC in range-extended hybrid buses.

[0004] To achieve the above objectives, this application adopts the following technical solution: Firstly, a method for SOC self-calibration of a range-extended bus BMS system is provided, comprising: the VCU sending a command to the range extender to start the SOC calibration mode according to preset trigger conditions; the range extender responding to the command, completing a self-test, and sending a confirmation command to the BMS to enter the SOC calibration mode; the BMS responding to the confirmation command, completing a self-test, entering the calibration state, and starting to send the current maximum allowable charging current value to the range extender in real time; the range extender receiving the current maximum allowable charging current value, and controlling the power generation unit in real time based on the maximum charging current value to charge the power battery pack through the power line; the BMS monitoring the charging state of the power battery pack in the calibration state, and when it determines that the full charge condition has been reached, completing the calibration calculation of the SOC value, and sending a command to the range extender to exit the SOC calibration mode; the range extender responding to the exit command, stopping calibration power generation, and the entire vehicle exiting the SOC calibration mode.

[0005] In conjunction with the first aspect mentioned above, in one possible implementation, the preset triggering conditions include at least: the vehicle's cumulative mileage reaches a set threshold, the vehicle is in a stationary state of not driving and not charging, and the vehicle has no safety faults that affect charging.

[0006] In conjunction with the first aspect mentioned above, in one possible implementation, the BMS dynamically calculates and sends the current maximum allowable charging current value based on the real-time state parameters of the power battery pack.

[0007] In conjunction with the first aspect mentioned above, in one possible implementation, the range extender generates electricity with a constant current or a controlled current that obeys dynamic commands from the BMS.

[0008] In conjunction with the first aspect above, in one possible implementation, the full charge condition is: at least one cell in the power battery pack reaches the charging cutoff voltage, and / or the total voltage reaches the full charge voltage threshold, and the charging current continuously drops below the set cutoff current.

[0009] In conjunction with the first aspect mentioned above, in one possible implementation, the method further includes, before S1: the BMS continuously collects the cell voltage and temperature of the power battery pack and collects the bus current to perform real-time SOC estimation.

[0010] Secondly, a SOC self-calibration system for a range-extended bus BMS system is provided, comprising: a power battery pack, a BMS, a vehicle VCU, and a range extender; the VCU, range extender, and BMS are connected via a vehicle CAN bus for transmitting commands and status data; the range extender and the power battery pack are connected via a vehicle high-voltage power line for transmitting calibration charging current; wherein, the VCU is configured to execute S1; the range extender is configured to execute S2, S4, and S6; and the BMS is configured to execute S3 and S5.

[0011] In conjunction with the second aspect above, in one possible implementation, the BMS includes: a SOC estimation module for performing real-time SOC estimation; a current limit calculation module for performing S3 in calibration state to calculate and send the currently allowed maximum charging current value; and a full charge determination module for performing S5 to determine the full charge condition.

[0012] In conjunction with the second aspect above, in one possible implementation, the range extender includes: a generator control module for receiving the currently allowed maximum charging current value and precisely controlling the generator's output power and current to execute S4.

[0013] In conjunction with the second aspect above, in one possible implementation, the VCU includes: a calibration trigger logic module, used to integrate preset trigger conditions and generate an instruction to start the SOC calibration mode to execute S1.

[0014] Thirdly, this application provides a SOC self-calibration device for a range-extended bus BMS system, comprising: a processor and a storage medium; the storage medium includes instructions, and the processor is configured to execute the instructions to implement the method described in the first aspect and any possible implementation thereof. This SOC self-calibration device for the range-extended bus BMS system can be an electronic device or a chip within an electronic device.

[0015] Fourthly, this application provides a computer-readable storage medium storing instructions that, when executed on a SOC self-calibration device of a range-extended bus BMS system, cause the SOC self-calibration device of the range-extended bus BMS system to perform the method described in the first aspect and any possible implementation thereof.

[0016] Fifthly, this application provides a computer program product containing instructions that, when run on the SOC self-calibration device of a range-extended bus BMS system, causes the SOC self-calibration device of the range-extended bus BMS system to perform the methods described in the first aspect and any possible implementation thereof.

[0017] This application provides a SOC self-calibration method and system for a range-extended electric vehicle's BMS system. After the vehicle returns to the depot, without charging piles or manual charging, the vehicle's VCU automatically wakes up the range extender and performs a small-current constant-current full charge on the power battery pack, using the maximum allowable charging current issued by the BMS in real time as the upper limit. Once the full charge condition is reached, the BMS immediately corrects the SOC to 100% and triggers cell equalization, then exits the calibration mode. The entire process requires no external power supply and does not occupy daytime operating time. It eliminates accumulated ampere-hour integral errors, suppresses the expansion of capacity differences between cells, and reduces SOC estimation errors, achieving the same effect as periodic external slow-charging calibration. This eliminates the need for onboard slow-charging sockets and customer-side charging pile construction, reducing overall vehicle costs and maintenance complexity.

[0018] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this application do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0019] Figure 1 A flowchart illustrating a SOC self-calibration method for a range-extended bus BMS provided in this application embodiment; Figure 2 A flowchart illustrating another SOC self-calibration method for a range-extended bus BMS provided in this application embodiment; Figure 3 A schematic diagram of the SOC self-calibration system of a range-extended bus BMS provided in this application embodiment; Figure 4 A schematic diagram of the SOC self-calibration device of a range-extended bus BMS provided in an embodiment of this application; Figure 5 This is a schematic diagram of the hardware structure of a SOC self-calibration device for a range-extended bus BMS provided in an embodiment of this application. Detailed Implementation

[0020] In the description of this application, unless otherwise stated, " / " means "or," for example, A / B can mean A or B. The "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, "at least one" means one or more, and "multiple" means two or more. The terms "first," "second," etc., do not limit the quantity or order of execution, and "first," "second," etc., do not necessarily imply differences.

[0021] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0022] Figure 1 This is a flowchart illustrating a SOC self-calibration method for a range-extended bus BMS system provided in an embodiment of this application. Figure 1 As shown, the SOC (State of Charge) self-calibration method of the BMS (Battery Management System) of a range-extended electric bus includes: In step S1, the VCU (Vehicle Control Unit) sends a command to the range extender to start the SOC calibration mode according to the preset trigger conditions.

[0023] Specifically, the triggering conditions include at least the following: the vehicle's cumulative mileage reaches a set threshold, the vehicle is in a stationary state where it is neither driving nor charging, and there are no safety faults affecting charging.

[0024] Furthermore, before the VCU makes a conditional trigger judgment, the BMS continuously collects the cell voltage and temperature of the power battery pack, as well as the bus current, to perform real-time SOC estimation.

[0025] In this embodiment, the VCU triggers the following conditions: the VCU uses the odometer to calculate the vehicle's cumulative mileage in real time. When the mileage reaches a pre-configured mileage threshold (which can be flexibly adjusted based on the daily operating mileage requirements of the city bus, initially set to 1000km), the VCU verifies the other three trigger conditions. The vehicle is in a non-driving state, i.e., the gear is in park or neutral, the electronic parking brake is fully engaged, and the real-time vehicle speed remains at 0km / h for 10 consecutive seconds. The vehicle is not in a charging state, i.e., the charging port's plug-in / plug-out detection remains disconnected, no external charging gun is inserted, and the charging current detected by the charging circuit current sensor is below 0.1A for 5 consecutive seconds. There are no safety faults affecting charging, i.e., the range extender does not report a fault that it cannot generate electricity normally, and the VCU itself does not detect any command transmission problems. When all the above conditions are met, the VCU sends a command to the range extender via the CAN bus to start the SOC calibration mode, formally triggering SOC self-calibration.

[0026] For example, a range-extended electric bus operating on a loop line between a core urban business district and a residential area has a preset SOC calibration mileage threshold of 1000km. After 4.5 days of continuous operation, the vehicle has accumulated 1008km of mileage. After the driver pulls the vehicle into a designated parking space at the depot, engages the parking gear, and pulls the electronic handbrake, the vehicle remains stationary for 12 seconds, maintaining a speed of 0km / h. At this time, no charging gun is inserted into the charging port, the charging circuit current is 0A for 6 consecutive seconds, and the VCU detects no engine ignition, generator excitation, or other power generation-related faults in the range extender. The CAN bus communication delay between the VCU and the BMS and range extender is ≤30ms, and command transmission is normal. After all triggering conditions are met, the VCU sends a command to the range extender via the CAN bus to start the SOC calibration mode, triggering this self-calibration process. The triggering logic precisely matches the bus operation intervals without requiring additional operating time, and ensures calibration safety through multi-dimensional status verification. After self-calibration is completed by the range extender, the error in the power battery SOC estimation is reduced, effectively avoiding the problem of limited power output caused by virtual SOC. At the same time, it does not rely on charging piles, reducing the construction cost of charging facilities at the depot.

[0027] Based on the above steps, by using the accumulated mileage judgment, non-driving, and fault-free automatic triggering logic, a full charge calibration of SOC is initiated at each threshold stage. This allows for timely correction of SOC error accumulation caused by voltage plateau periods and cell inconsistencies in lithium iron phosphate batteries without manual intervention. This significantly improves the accuracy of SOC estimation and effectively avoids the impact of phantom charge on user experience.

[0028] In step S2, the range extender responds to the instruction, completes the self-test, and sends a confirmation instruction to the BMS to enter the SOC calibration mode.

[0029] Specifically, after receiving the command from the VCU to start the SOC calibration mode, the range extender immediately performs a rapid diagnostic on its own fuel system, generator temperature, speed sensor and high voltage rectifier module. If all self-test items are fault-free, it sends a confirmation command to the BMS to enter the SOC calibration mode.

[0030] Based on the above steps, the closed-loop handshake of self-testing and confirmation ensures the reliability of the range extender's power generation capability, avoids the range extender from entering the calibration mode with hidden dangers, and thus ensures the stability and safety of the subsequent small current full charge process, eliminating the risk of calibration interruption or battery overcharging due to range extender failure.

[0031] In step S3, the BMS responds to the confirmation command, completes the self-test, enters the calibration state, and begins to send the current maximum allowable charging current value to the range extender in real time.

[0032] Specifically, the BMS dynamically calculates and sends the current maximum allowable charging current value based on the real-time status parameters of the power battery pack. After receiving the confirmation command from the range extender to enter the SOC calibration mode, the BMS immediately performs self-checks on the high-voltage insulation, single-cell voltage sampling, temperature sensor, current acquisition, and equalization circuit. If all diagnostic results are normal and there are no faults affecting charging, the BMS dynamically calculates the SOC value based on the highest single-cell voltage, battery temperature, and bus current, calculates the current maximum allowable charging current value, and continuously sends this maximum charging current value to the range extender to ensure that the range extender's power generation output is always within the battery safety boundary, providing real-time closed-loop protection for subsequent small-current full charging.

[0033] Based on the above steps, the BMS uses a three-level strategy of self-testing, dynamic current limiting, and real-time protection to keep the power output of the range extender within the battery safety boundary. This ensures that the voltage platform at the end of a small-current full charge can be accurately captured, and that the equalization circuit can be activated throughout the entire process. Thus, in nighttime return scenarios without charging stations, personnel, or external power sources, it can complete the periodic SOC zeroing and capacity correction equivalent to a slow charging station, maintain a low estimation error, and achieve self-maintenance of SOC accuracy and battery consistency throughout the entire life cycle of the range-extended bus.

[0034] In step S4, the range extender receives the current maximum allowable charging current value and controls the power generation unit in real time based on the maximum charging current value to charge the power battery pack through the power line.

[0035] Specifically, the range extender generates electricity with a constant current or a controlled current that follows dynamic commands from the BMS. After receiving the maximum allowable charging current value, the range extender periodically samples the generator output current and compares it with the maximum charging current. If the deviation exceeds 1A, it adjusts the range extender engine speed and generator current while keeping the output current below the current maximum allowable charging current. It continuously injects a small current into the power battery through the power line until the BMS issues a new command, thereby achieving full-time closed-loop control and ensuring a smooth, safe, and unaffected full-charge process.

[0036] Based on the above steps, the closed-loop control scheme ensures that the current error throughout the full charging process is less than 1A, eliminating dependence on the external power grid. In the scenario of charging without a charging station at night, it achieves safe and stable low-current full charging equivalent to slow charging stations, providing stable and controllable energy input for subsequent SOC calibration.

[0037] In step S5, the BMS monitors the charging status of the power battery pack in calibration mode. When it determines that the full charge condition has been reached, it completes the calibration calculation of the SOC value and sends a command to the range extender to exit the SOC calibration mode.

[0038] Specifically, the full charge conditions are: at least one cell in the power battery pack reaches the charging cut-off voltage, and / or the total voltage reaches the full charge voltage threshold, and the charging current continuously drops below the set cut-off current; the BMS periodically collects voltage, temperature and bus current in calibration mode. When the voltage or temperature exceeds the reference value and the charging current remains below 0.05C (rated capacity current) for 120 seconds, or the total voltage reaches the preset full charge voltage threshold and the current drops below the cut-off current, the SOC estimate is corrected to 100%, the high-voltage cells are bypassed and discharged, and a command to exit the SOC calibration mode is sent to the range extender, thereby completing the zeroing of ampere-hour integral error, capacity reference reset and consistency repair, achieving the periodic full charge calibration effect equivalent to that of an external slow charging pile.

[0039] Based on the above steps, when the battery is detected to be about to reach 100% SOC, the estimated value is forcibly corrected and equalization is initiated. This not only eliminates the drift error accumulated over a long period of time in the ampere-hour integral, but also brings the single-cell voltage difference to within 0.05 C (C is the rated capacity). This achieves periodic full-charge calibration without relying on external charging piles, and the equalization effect is equivalent to the weekly maintenance charging of a slow charging pile. As a result, the capacity is available and the range is reliable throughout the life cycle. At the same time, the vehicle slow charging socket and supporting infrastructure are eliminated, which significantly reduces the overall vehicle cost and maintenance complexity.

[0040] In step S6, the range extender responds to the exit command, stops calibration power generation, and the vehicle exits the SOC calibration mode.

[0041] After receiving the exit SOC calibration command from the BMS, the range extender's generator control unit (GUC) executes a smooth shutdown procedure. First, it linearly reduces the generator current to 0 within 2 seconds. Then, it disconnects the high-voltage contactor connected to the power battery pack. Finally, it switches the range extender to standby or driving generator mode. At the same time, after sending the exit command and confirming that the range extender has performed the current reduction action, the BMS switches its own state to normal driving monitoring mode and corrects and stores the estimated SOC parameters based on the full charge calibration results. At this point, the vehicle returns to the ready state for normal driving, and the complete SOC self-calibration process loop ends.

[0042] Figure 2 A flowchart illustrating the SOC self-calibration method for a range-extended bus BMS system provided in this application embodiment is shown below. Figure 2 As shown, the SOC self-calibration method for the BMS system of a range-extended electric bus includes the following steps: First, the vehicle's VCU triggers a command to enter calibration mode when preset conditions are met; then the range extender performs a rigorous self-test; after passing the self-test, it sends a command to the BMS to enter calibration mode; then the BMS performs a self-test, and if it passes, the BMS sends the maximum allowable charging current to the range extender; the range extender precisely controls power generation according to the charging current allowed by the BMS; after the power battery pack is fully charged, the BMS completes the SOC calibration and sends a command to exit SOC calibration mode.

[0043] For example, when a range-extended electric bus reaches a cumulative mileage threshold of 1000km, the VCU confirms that the vehicle is parked and stationary, without external charging and without safety faults, triggering a calibration command. The range extender then self-checks the engine, generator, and communication system, and after confirming no faults, sends a calibration mode entry signal to the BMS. After the BMS self-checks the cell acquisition module, current sensor, and other components and confirms they are qualified, it sends the maximum allowable charging current of 20A to the range extender. The range extender precisely controls the generator to output a 20A current to charge the power battery pack. When the BMS detects that the cell voltage has reached the full charge threshold and the charging current has dropped below 5A, it completes the SOC calibration and sends an exit command to the range extender, ending the entire calibration process. This process enables precise and controlled charging of the range extender, without dependence on external charging piles. The SOC estimation error after calibration is ≤3%, effectively eliminating the estimation deviation during the voltage plateau period of lithium iron phosphate batteries. At the same time, it triggers cell equalization, improving battery consistency and lifespan, saving the cost of configuring charging sockets for the entire vehicle and constructing charging piles at the depot, thus meeting the needs of efficient bus operation.

[0044] Based on the above judgment process, a layered, safe, closed-loop automated control system is implemented. Through the deep integration of intelligent decision-making of the entire vehicle, the controllable power generation capability of the range extender, and the battery state management of the BMS, it is possible to autonomously complete accurate SOC calibration, equivalent to the calibration effect of a slow charging pile, without relying on external charging facilities. This not only solves the problem of accumulated error in SOC estimation caused by the voltage plateau characteristics of lithium iron phosphate batteries, but also provides the battery pack with the convenience and reliability of range-extended hybrid buses in actual operation by periodically triggering the full charge process.

[0045] Figure 3 A system structure diagram of a SOC self-calibration system for a range-extended bus BMS system provided in this application embodiment is shown below. Figure 3 As shown, the SOC self-calibration system structure of the range-extended bus BMS includes: a power battery pack, a BMS, a vehicle VCU, and a range extender; the VCU, range extender, and BMS are connected via the vehicle CAN bus for transmitting commands and status data; the range extender and the power battery pack are connected via the vehicle high-voltage power line for transmitting calibration charging current; wherein, the VCU is configured to execute the above step S1; the range extender is configured to execute steps S2, S4, and S6; and the BMS is configured to execute the above steps S3 and S5.

[0046] Specifically, the vehicle's VCU serves as the decision-making starting point of the method, issuing accurate commands based on the vehicle's operating status and preset conditions; the range extender, as a controllable power generation unit, receives real-time current commands from the BMS and converts them into accurate charging output; the BMS, as the core controller of the calibration process, dynamically calculates the safe current boundary and monitors the charging process until SOC calibration is completed; the vehicle's CAN bus serves as the system's information transmission channel to ensure real-time and reliable interaction of commands and status between various components; and the power line, as the energy transmission channel, safely delivers the electrical energy generated by the range extender to the power battery pack.

[0047] Furthermore, the BMS includes: a SOC estimation module for performing real-time SOC estimation; a current limit calculation module for performing S3 in calibration state, calculating and sending the currently allowed maximum charging current value; and a full charge determination module for performing step S5 to determine the full charge condition.

[0048] Furthermore, the range extender includes a generator control module for receiving the currently allowed maximum charging current value and precisely controlling the generator's output power and current to execute S4.

[0049] Furthermore, the VCU includes: a calibration trigger logic module, used to integrate the preset trigger conditions and generate the instruction to start the SOC calibration mode to execute S1.

[0050] For example, the SOC self-calibration system of the range-extended electric bus BMS system consists of a lithium iron phosphate power battery pack, BMS, vehicle VCU, and a 1.5T range extender. The VCU, range extender, and BMS achieve real-time interaction of commands and status data through the vehicle's CAN bus. The range extender and power battery pack transmit calibration charging current through a high-voltage power line. The VCU initiates calibration commands based on the calibration trigger logic module, the range extender achieves precise current output through the power generation control module, and the BMS completes full-process charging management and SOC calibration through the SOC estimation module, current limit calculation module, and full charge determination module. This system architecture eliminates the need for vehicle charging socket hardware configuration and does not rely on external charging piles, achieving on-board autonomous SOC self-calibration. The CAN bus ensures command transmission latency ≤50ms, the range extender charging current control accuracy reaches ±1A, and the SOC estimation error after calibration is ≤3%. This effectively solves the problem of voltage plateau estimation deviation in lithium iron phosphate batteries, while ensuring cell consistency, extending battery pack cycle life, significantly reducing the operating costs of urban buses and station facilities, and adapting to the needs of large-scale commercial vehicle operation.

[0051] Based on the above system architecture, the SOC self-calibration function becomes an integrated capability of the vehicle itself, without relying on external charging facilities. This effectively solves the problem of decreased SOC estimation accuracy and lack of battery balancing caused by the inability of extended-range buses to connect to charging piles regularly during operation.

[0052] The above primarily describes the solutions of the embodiments of this application from the perspective of device implementation. It is understood that each device, for example, a SOC self-calibration device for a range-extended bus BMS, includes at least one of the hardware structures and software modules corresponding to the execution of each function in order to achieve the above-mentioned functions. Those skilled in the art should readily recognize that, in conjunction with the units and algorithm steps of the various examples described in the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0053] This application embodiment can divide the SOC self-calibration device of a range-extended bus BMS into functional units according to the above method example. For example, each function can be divided into a separate functional unit, or two or more functions can be integrated into one processing unit. The integrated unit can be implemented in hardware or as a software functional unit. It should be noted that the unit division in this application embodiment is illustrative and only represents a logical functional division. In actual implementation, there may be other division methods.

[0054] When using integrated units, Figure 4 A possible structural schematic diagram of a range-extended bus BMS SOC self-calibration device (referred to as a range-extended bus BMS SOC self-calibration device 40) involved in the above embodiments is shown. The range-extended bus BMS SOC self-calibration device 40 includes a processing unit 401 and a communication unit 402, and may also include a storage unit 403. Figure 4 The schematic diagram shown can be used to illustrate the structure of a SOC self-calibration device for a range-extended bus BMS involved in the above embodiments.

[0055] when Figure 4 The schematic diagram shown illustrates the structure of a SOC self-calibration device for a range-extended bus BMS as described in the above embodiments. The processing unit 401 is used to control and manage the operation of the SOC self-calibration device for a range-extended bus BMS. The communication unit 402 is used for the SOC self-calibration device for a range-extended bus BMS to communicate with other devices. The storage unit 403 is used to store the program code and data of the SOC self-calibration device for a range-extended bus BMS.

[0056] For example, communication unit 402 is used for communication between the power battery pack, BMS, vehicle VCU, and range extender based on the CAN bus.

[0057] The processing unit 401 is used to perform core computational processing tasks such as calibration mode trigger determination, self-test logic execution, precise control of charging current, SOC calculation and calibration execution.

[0058] This includes communication interfaces, transceivers, transceiver circuits, and transceiver devices. "Communication interface" is a general term and can include one or more interfaces. Storage unit 403 can be a memory. When the SOC self-calibration device 40 of a range-extended bus BMS is a chip, the processing unit 401 can be a processor or controller, and the communication unit 402 can be an input interface and / or output interface, pins, or circuits. Storage unit 403 can be a storage unit within the chip (e.g., registers, caches, etc.) or a storage unit located outside the chip (e.g., read-only memory (ROM), random access memory (RAM, etc.)).

[0059] The communication unit can also be called a transceiver unit. The antenna and control circuit with transceiver functions in a range-extended bus BMS SOC self-calibration device 40 can be considered as a communication unit 402 of the range-extended bus BMS SOC self-calibration device 40, and the processor with processing functions can be considered as a processing unit 401 of the range-extended bus BMS SOC self-calibration device 40. Optionally, the device in the communication unit 402 used to implement the receiving function can be considered as a communication unit, which is used to execute the receiving steps in the embodiments of this application. The communication unit can be a receiver, a receiver circuit, etc. The device in the communication unit 402 used to implement the transmitting function can be considered as a transmitting unit, which is used to execute the transmitting steps in the embodiments of this application. The transmitting unit can be a transmitter, a transmitter, a transmitting circuit, etc.

[0060] Figure 4 If the integrated units in the process are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the embodiments of this application, in essence, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. Storage media for storing computer software products include various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.

[0061] Figure 4 The units in the process can also be called modules; for example, a processing unit can be called a processing module.

[0062] This application embodiment also provides a hardware structure diagram of a range-extended bus BMS SOC self-calibration (denoted as range-extended bus BMS SOC self-calibration device 50), see [link to relevant documentation]. Figure 5 The SOC self-calibration device 50 of the range-extended bus BMS includes a processor 501, and optionally, a memory 502 connected to the processor 501.

[0063] In the first possible implementation, see Figure 5A self-calibration device 50 for the State of Charge (SOC) of a range-extended electric vehicle (BMS) further includes a transceiver 503. The processor 501, memory 502, and transceiver 503 are connected via a bus. The transceiver 503 is used to communicate with other devices or communication networks. Optionally, the transceiver 503 may include a transmitter and a receiver. The device in the transceiver 503 that implements the receiving function can be considered as a receiver, which is used to perform the receiving steps in the embodiments of this application. The device in the transceiver 503 that implements the transmitting function can be considered as a transmitter, which is used to perform the transmitting steps in the embodiments of this application.

[0064] Based on the first possible implementation method Figure 5 The schematic diagram shown can be used to illustrate the structure of a SOC self-calibration device for a range-extended bus BMS involved in the above embodiments.

[0065] in, Figure 5 The diagram also illustrates a system chip in the SOC self-calibration device of a range-extended bus BMS. In this case, the actions performed by the aforementioned range-extended bus BMS SOC self-calibration device can be implemented by this system chip; the specific actions performed are described above and will not be repeated here.

[0066] In implementation, each step of the method provided in this embodiment can be completed by integrated logic circuits in the processor or by instructions in software form. The steps of the method disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or being executed by a combination of hardware and software modules in the processor.

[0067] The processor in this application may include, but is not limited to, at least one of the following: a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a microcontroller unit (MCU), or an artificial intelligence processor, etc., which are various computing devices that run software. Each computing device may include one or more cores for executing software instructions to perform calculations or processing. The processor may be a separate semiconductor chip or integrated with other circuits into a single semiconductor chip. For example, it may be integrated with other circuits (such as encoding / decoding circuits, hardware acceleration circuits, or various bus and interface circuits) to form a System-on-a-Chip (SoC), or it may be integrated as a built-in processor within an ASIC. The ASIC with the integrated processor may be packaged separately or together with other circuits. In addition to the cores for executing software instructions to perform calculations or processing, the processor may further include necessary hardware accelerators, such as field-programmable gate arrays (FPGAs), PLDs (programmable logic devices), or logic circuits that implement dedicated logic operations.

[0068] The memory in the embodiments of this application may include at least one of the following types: read-only memory (ROM) or other types of static storage devices capable of storing static information and instructions; random access memory (RAM) or other types of dynamic storage devices capable of storing information and instructions; or electrically erasable programmable-only memory (EEPROM). In some scenarios, the memory may also be a compact disc read-only memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed optical discs, laser discs, optical discs, digital universal optical discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures and accessible by a computer, but is not limited thereto.

[0069] This application also provides a computer-readable storage medium including instructions that, when run on a computer, cause the computer to perform any of the methods described above.

[0070] This application also provides a computer program product containing instructions that, when run on a computer, cause the computer to perform any of the methods described above.

[0071] This application also provides a chip including a processor and an interface circuit. The interface circuit is coupled to the processor. The processor is used to run computer programs or instructions to implement the above-described method. The interface circuit is used to communicate with other modules outside the chip.

[0072] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software programs, implementation can be, in whole or in part, in the form of a computer program product. This computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device containing one or more servers, data centers, etc., that can be integrated with the medium. The available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state disks (SSDs)).

[0073] Although this application has been described herein in conjunction with various embodiments, those skilled in the art, by reviewing the accompanying drawings, disclosure, and appended claims, will understand and implement other variations of the disclosed embodiments in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple instances. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0074] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if such modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, this application is also intended to include such modifications and modifications.

Claims

1. A method for SOC self-calibration of a BMS system for a range-extended electric bus, characterized in that, A SOC self-calibration system applied to a BMS system for a range-extended bus, the method comprising: S1, VCU sends a command to the range extender to start the SOC calibration mode according to the preset trigger conditions; S2, the range extender responds to the instruction, completes the self-test, and sends a confirmation instruction to the BMS to enter the SOC calibration mode; S3, in response to the confirmation command, the BMS completes the self-test and enters the calibration state, and begins to send the current maximum allowable charging current value to the range extender in real time; S4, the range extender receives the current maximum allowable charging current value and controls the power generation unit in real time based on the maximum charging current value to charge the power battery pack through the power line; S5, the BMS monitors the charging status of the power battery pack in calibration mode. When it determines that the full charge condition has been reached, it completes the calibration calculation of the SOC value and sends an instruction to the range extender to exit the SOC calibration mode. S6, the range extender responds to the exit command, stops calibration power generation, and the vehicle exits the SOC calibration mode; The command transmission between the vehicle's VCU, range extender, and BMS is completed through the vehicle's CAN bus.

2. The SOC self-calibration method for a range-extended bus BMS system according to claim 1, characterized in that, The preset triggering conditions include at least the following: the vehicle's cumulative mileage reaches a set threshold, the vehicle is in a stationary state where it is neither driving nor charging, and there are no safety faults affecting charging.

3. The SOC self-calibration method for a range-extended bus BMS system according to claim 1, characterized in that, The BMS dynamically calculates and sends the current maximum allowable charging current value based on the real-time status parameters of the power battery pack.

4. The SOC self-calibration method for a range-extended bus BMS system according to claim 1, characterized in that, The range extender generates electricity with a constant current or a controlled current that obeys dynamic commands from the BMS.

5. The SOC self-calibration method for a range-extended bus BMS system according to claim 1, characterized in that, The full charge condition is as follows: at least one cell in the power battery pack reaches the charging cutoff voltage, and / or the total voltage reaches the full charge voltage threshold, and the charging current continuously drops below the set cutoff current.

6. The SOC self-calibration method for a range-extended bus BMS system according to claim 1, characterized in that, Before executing S1, the following are also included: The BMS continuously collects the cell voltage and temperature of the power battery pack, and collects the bus current to perform real-time SOC estimation.

7. A SOC self-calibration system for a range-extended electric bus BMS system, characterized in that, The system includes: a power battery pack, a BMS, a vehicle VCU, and a range extender; The VCU, range extender, and BMS are connected via the vehicle's CAN bus for transmitting commands and status data. The range extender is connected to the power battery pack via the vehicle's high-voltage power line for transmitting calibration charging current; The VCU is configured to execute S1; The range extender is configured to execute S2, S4, and S6; The BMS is configured to execute S3 and S5.

8. The SOC self-calibration system for a range-extended bus BMS system according to claim 7, characterized in that, The BMS includes: The SOC estimation module is used to perform real-time SOC estimation. The current limit calculation module is used to perform S3 in calibration state, calculate and send the current maximum allowed charging current value; The full charge determination module is used to execute S5 and determine the full charge condition.

9. The SOC self-calibration system for a range-extended bus BMS system according to claim 7, characterized in that, The range extender includes: The power generation control module is used to receive the current maximum allowable charging current value and precisely control the output power and current of the generator to execute S4.

10. The SOC self-calibration system for a range-extended bus BMS system according to claim 7, characterized in that, The VCU includes: The calibration trigger logic module is used to integrate the preset trigger conditions and generate the instruction to start the SOC calibration mode to execute S1.

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