DC bus short-circuit protection control method and device for range extender and range extender system

Abstract

The present invention discloses a method and device for controlling short-circuit protection of a DC busbar of a range extender, and a range extender system. The method includes detecting whether a short-circuit fault has occurred in the DC busbar of the range extender; when a short-circuit fault is detected in the DC busbar of the range extender, active short-circuit protection is initiated, and the engine controller of the range extender receives a short-circuit protection instruction to control the engine of the range extender to reduce speed; and the generator controller of the range extender receives a short-circuit protection instruction to control the generator of the range extender to generate braking torque, accelerating the engine to stop rotation. The present invention implements DC busbar short-circuit protection solely through a control strategy, eliminating the need for additional detection circuits and switches, and without increasing equipment costs, and can quickly achieve DC busbar short-circuit protection.

Description

Technical Field

[0001] The present invention relates to the field of busbar short-circuit protection, and in particular to a direct current (DC) busbar short-circuit protection control method and device for a range extender, and a range extender system. Background Art

[0002] To address the problem of detecting a short circuit in the range extender's DC output busbar, existing vehicle range extenders typically incorporate a detection and protection unit and a thermistor between the range extender's controller and the battery pack. This unit detects a voltage level signal and controls a start switch in the circuit to protect the DC circuit. However, this approach requires an additional detection circuit and switch between the controller and the battery pack, increasing control complexity, costs, and space requirements in the vehicle. Summary of the Invention

[0003] Embodiments of the present invention provide a method and device for controlling a DC bus short-circuit protection of a range extender, and a range extender system, to solve the problems in the prior art of adding a detection loop, making short-circuit protection control complex, and increasing costs.

[0004] A DC bus short-circuit protection control method for a range extender, comprising:

[0005] Check whether the DC bus of the range extender has a short circuit fault;

[0006] When a short circuit fault is detected in the DC bus of the range extender, the DC bus short circuit protection is activated, and the engine controller of the range extender receives the short circuit protection instruction to control the engine of the range extender to slow down; the generator controller of the range extender receives the short circuit protection instruction to control the generator of the range extender to generate braking torque and accelerate the engine to stop rotation.

[0007] A DC bus short-circuit protection control device for a range extender, comprising:

[0008] a generator controller configured to detect whether a short circuit fault occurs in the DC bus of the range extender; when a short circuit fault is detected in the DC bus of the range extender, the controller sends a fault status signal to the vehicle controller and receives a short circuit protection instruction from the vehicle controller to control the generator of the range extender to generate a braking torque and accelerate the engine to stop rotation;

[0009] The engine controller is used to receive a short-circuit protection instruction sent by the vehicle controller to control the engine speed reduction of the range extender.

[0010] A range extender system, the range extender system comprising:

[0011] An engine and an engine controller, wherein a control output of the engine controller is connected to a control input of the engine;

[0012] A generator and a generator controller, wherein a control output of the generator controller is connected to a control input of the generator;

[0013] The generator controller and the engine controller are used to jointly implement the above-mentioned DC bus short-circuit protection control method.

[0014] The aforementioned DC bus short-circuit protection control method, device, and range extender system send short-circuit protection commands to the range extender's engine and generator when a short-circuit fault occurs in the range extender's DC bus. This control reduces the engine speed and generates braking torque in the range extender's generator, accelerating the engine to a stop. This method implements active short-circuit protection solely through a control strategy, eliminating the need for additional detection circuits and switches, and minimizing equipment costs. The system can rapidly implement DC bus short-circuit protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0016] Figure 1 2 is a schematic diagram of an application environment of a DC bus short-circuit protection control method for a range extender according to an embodiment of the present invention;

[0017] Figure 2 This is a flow chart of a DC bus short-circuit protection control method for a range extender in one embodiment of the present invention;

[0018] Figure 3 is another flow chart of a DC bus short-circuit protection control method for a range extender in one embodiment of the present invention;

[0019] Figure 4 1 is a schematic diagram of a DC bus short-circuit protection control device according to an embodiment of the present invention;

[0020] Figure 5 is a circuit topology diagram of a range extender system in one embodiment of the present invention;

[0021] Figure 6 FIG. 1 is a schematic diagram of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] The DC bus short circuit protection control method for a range extender provided by an embodiment of the present invention can be applied as follows: Figure 1 Specifically, the DC bus short circuit protection control method is applied in a range extender system, which includes the following: Figure 1 The engine controller and generator controller shown communicate with the vehicle controller through the network to implement DC bus short-circuit protection control of the range extender.

[0024] In one embodiment, if Figure 2 As shown, a DC bus short-circuit protection control method for a range extender is provided, which is applied in Figure 1 The engine controller and generator controller in the example are used to illustrate the process, including the following steps:

[0025] S201, detecting whether a short circuit fault occurs in the DC bus of the range extender;

[0026] The DC bus voltage of the range extender can be monitored in real time. When the DC bus voltage drops to or below a certain fault voltage threshold Uh, a DC bus short circuit fault is determined. Specifically, the fault voltage threshold Uh can be the highest threshold set based on historical fault voltage data.

[0027] S202, when a short circuit fault is detected in the DC bus of the range extender, the DC bus short circuit protection is activated, the engine controller of the range extender receives the short circuit protection instruction to control the engine of the range extender to reduce the speed; the generator controller of the range extender receives the short circuit protection instruction to control the generator of the range extender to generate braking torque to accelerate the engine to stop rotation.

[0028] When a DC target transmission short-circuit fault is detected, the generator controller feeds the short-circuit fault status bit (SC) back to the vehicle controller. If the vehicle controller determines that the short-circuit fault status bit (SC) is valid, it exits the power generation mode and enters the short-circuit protection mode, initiating active short-circuit protection. Specifically, the vehicle controller sends a short-circuit protection command to the engine controller and generator controller. Upon receiving the command, the engine controller controls the engine to slow down, while the generator controller controls the generator to generate braking torque to accelerate the engine to a stop.

[0029] The DC bus short-circuit protection control method of this embodiment sends short-circuit protection instructions to the range extender's engine and generator when a short-circuit fault occurs in the range extender's DC bus. This method controls the range extender's engine to slow down, and controls the range extender's generator to generate braking torque, accelerating the engine to stop. The present invention utilizes the existing range extender system and implements active short-circuit protection solely through a control strategy. It does not require additional detection circuits and switches, and can quickly implement DC bus short-circuit protection without increasing equipment costs. Since the short-circuit current flowing through the range extender system is equal to the motor short-circuit current when the DC output bus is short-circuited, its value is not too large. The control system's protection delay is at the millisecond level, effectively providing protection.

[0030] In one embodiment, if Figure 3 As shown, the DC bus short circuit fault control method further includes:

[0031] After the generator controller receives the short-circuit protection instruction, obtaining the current speed of the generator in real time;

[0032] When the current speed of the generator is greater than a preset high speed threshold value, the active short circuit protection mode is entered to control the generator of the range extender to generate a first braking torque;

[0033] When the current speed of the generator is not greater than a preset high speed threshold value, the power device shutdown protection mode is entered, and the generator of the range extender is controlled to generate a second braking torque, which is less than the first braking torque.

[0034] Among them, considering that a large torque will be generated when the generator speed is low, which has an adverse effect on the shutdown of the engine crankshaft, therefore, by detecting the current speed of the generator, when the current speed of the generator is high, for example, greater than the high speed threshold value w1, the ASC (Active Short Circuit) protection mode is entered, and the relatively high first braking torque generated by the generator is used to assist in accelerating the engine to stop rotation.

[0035] When the current speed of the generator is low, for example, less than or equal to the high speed threshold value w1, the SPO (Switching Pulse Off) protection mode is entered, and the generator of the range extender is controlled to generate a lower second braking torque to assist in accelerating the engine to stop rotation.

[0036] When the generator controller GCU detects that the generator speed drops to 0, it will exit the short-circuit protection state and send it to the vehicle controller VCU. When the vehicle controller VCU receives the exit of the short-circuit protection state from the generator controller GCU, it controls the exit of the short-circuit protection mode and enters the shutdown mode, and sends a shutdown command to the engine controller EMS and the generator controller GCU to stop working, and save the fault status bit SC until the fault is recovered and manually cleared, and then the next startup operation can be carried out, otherwise starting is prohibited.

[0037] The DC bus short-circuit protection control method of this embodiment controls the generator to generate braking torques of different sizes by real-time detection and judgment of the current rotation speed of the generator, more reasonably accelerating the engine crankshaft to stop rotation and shortening the action time of the generator back electromotive force.

[0038] In one embodiment, controlling the generator of the range extender to generate the first braking torque includes:

[0039] The upper arm switch tubes or the lower arm switch tubes of the generator controller are controlled to be fully turned on, so that the three-phase winding of the generator is actively short-circuited, so that the generator generates a first braking torque.

[0040] Among them, the upper arm switching tube and the lower arm switching tube of the generator controller are both composed of IGBTs. After entering the ASC protection mode, the generator controller controls the upper arm or the lower arm to be fully turned on, so that the three-phase winding of the motor is actively short-circuited, thereby preventing the current from flowing to the DC bus side, and generating a braking torque to accelerate the engine crankshaft to stop rotating and shorten the action time of the generator back electromotive force.

[0041] In one embodiment, controlling the generator of the range extender to generate the second braking torque includes:

[0042] The upper arm switch tubes and the lower arm switch tubes of the generator controller are controlled to be completely turned off, so that the generator generates a second braking torque lower than the first braking torque.

[0043] Among them, after entering the SPO protection mode, the upper bridge arm switch tube and the lower bridge arm switch are completely turned off to reduce the impact of the braking torque on the engine crankshaft.

[0044] In one embodiment, sending a short circuit protection instruction to the engine controller of the range extender to control the engine speed reduction of the range extender includes:

[0045] After receiving the short-circuit protection instruction, the engine controller of the range extender generates a zero torque instruction to control the engine to reduce speed.

[0046] The DC bus short-circuit protection control method of this embodiment can solve the protection of the range extender's DC output bus short circuit through the cooperation of the engine controller and the generator controller, and can effectively isolate the range extender system from the short-circuit loop. Short-circuit protection can be achieved without the help of an external circuit, effectively protecting the range extender system.

[0047] In one embodiment, if Figure 3 As shown, the detection of whether a short circuit fault occurs in the DC bus of the range extender includes:

[0048] The supporting capacitor voltage of the generator controller is acquired in real time. When it is detected that the supporting capacitor voltage is continuously less than or equal to a preset voltage threshold within a continuous preset time period, it is determined that a short circuit fault occurs on the DC bus.

[0049] A supporting capacitor is connected in parallel to the generator controller's circuit output (i.e., the DC output bus). When the DC output bus circuit is short-circuited, the energy stored in the supporting capacitor is lost through the short-circuit circuit. Therefore, a DC bus short-circuit fault can be confirmed by monitoring the supporting capacitor voltage Udc over a continuous preset time period t. When this voltage is less than or equal to a preset voltage threshold U, a DC bus short-circuit fault is detected. The generator controller (GCU) feeds the short-circuit fault status bit SC back to the vehicle controller (VCU). When the logic of the short-circuit fault status bit SC is TRUE, a short-circuit fault has occurred.

[0050] It should be understood that the order of execution of the steps in the above embodiments does not necessarily mean the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0051] In one embodiment, a DC bus short-circuit protection control device for a range extender is provided. The DC bus short-circuit protection control device corresponds to the DC bus short-circuit protection control method in the above embodiment. Figure 4 As shown, the DC bus short-circuit protection control device includes a generator controller 41 and an engine controller 42. The functional modules are described in detail as follows:

[0052] The generator controller 41 is configured to detect whether a short circuit fault occurs in the DC bus of the range extender; when a short circuit fault is detected in the DC bus of the range extender, the generator controller 41 sends a fault status signal to the vehicle controller and receives a short circuit protection instruction from the vehicle controller to control the generator of the range extender to generate a braking torque and accelerate the engine to stop rotation;

[0053] The engine controller 42 is used to receive the short-circuit protection instruction sent by the vehicle controller to control the engine speed reduction of the range extender.

[0054] Optionally, the generator controller 41 is further used to obtain the current speed of the generator in real time after receiving the short-circuit protection instruction; when the current speed of the generator is greater than a preset high speed threshold value, control the generator of the range extender to generate a first braking torque; when the current speed of the generator is not greater than the preset high speed threshold value, control the generator of the range extender to generate a second braking torque, and the second braking torque is less than the first braking torque.

[0055] Optionally, the generator controller 41 is further used to control the upper arm switch tubes or the lower arm switch tubes of the generator controller to be fully turned on, so as to actively short-circuit the three-phase winding of the generator and enable the generator to generate a first braking torque.

[0056] Optionally, the generator controller 41 is further configured to control the upper arm switch tubes and the lower arm switch tubes of the generator controller to be completely turned off, so that the generator generates a second braking torque that is lower than the first braking torque.

[0057] Optionally, the engine controller 42 is configured to generate a zero torque instruction after receiving the short-circuit protection instruction to control the engine to decelerate.

[0058] Optionally, the generator controller 41 is further used to obtain the support capacitor voltage of the generator controller in real time. When it is detected that the support capacitor voltage is continuously less than or equal to a preset voltage threshold within a continuous preset time period, it is determined that a short circuit fault occurs in the DC bus.

[0059] The specific definitions of the DC bus short-circuit protection control device can be found in the definitions of the DC bus short-circuit protection control method above and will not be repeated here. Each module in the aforementioned DC bus short-circuit protection control device can be implemented in whole or in part via software, hardware, or a combination thereof. Each of the aforementioned modules can be embedded in or independent of a processor in a computer device in hardware form, or can be stored in a memory in the computer device in software form, so that the processor can call and execute the corresponding operations of each of the aforementioned modules.

[0060] In one embodiment, Figure 5 The circuit topology of the range extender system shown in the figure includes an engine, an engine controller (EMS), a generator, and a generator controller (GCU), wherein the control output of the engine controller is connected to the control input of the engine, the control output of the generator controller is connected to the control input of the generator, the engine crankshaft is connected to the generator rotor shaft, the engine controller EMS is used to control the engine, and the generator controller GCU is used to control the generator.

[0061] The engine controller (EMS) and generator controller (GCU) communicate with the vehicle controller (VCU), respectively. Under normal power generation conditions, the VCU controls the amount of power generated by sending torque commands to the EMS to control engine torque and speed commands to the GCU to control generator speed. The motor speed signal is fed back to the GCU in real time via a hardwired connection. When the range extender system is in power generation mode, the engine drives the generator. If the DC bus output terminal AB is short-circuited and the generator back EMF is too high, current will flow through the GCU through uncontrolled rectification diodes. If not promptly addressed, the GCU will be damaged.

[0062] The generator controller and the engine controller of this embodiment are used to jointly implement the DC bus short-circuit protection control method in the previous DC bus short-circuit protection control method embodiment.

[0063] Optionally, the range extender system further includes a vehicle controller VCU, which is configured to receive a fault status signal sent by the generator controller, determine a short circuit fault occurs in the DC bus according to the fault status signal, and send short circuit protection instructions to the engine controller and the generator controller respectively.

[0064] like Figure 3 As shown in the figure, when the system is running, the generator controller GCU detects the support capacitor voltage Udc in real time and compares it with the preset voltage threshold U. If Udc≤U within time t, the generator controller GCU will feed back the short-circuit fault status bit SC to the vehicle controller VCU. When the SC logic is TRUE, the short-circuit fault is established.

[0065] When the vehicle controller (VCU) determines that SC is TRUE, it exits power generation mode and enters short-circuit protection mode. It sends short-circuit protection commands to the engine controller (EMS) and the generator controller (GCU). The EMS sends a zero torque command to slow the engine, while the GCU compares the current generator speed (W) with the speed threshold (W1). When W>W1, it uses ASC protection mode; when W≤W1, it uses SPO protection mode. When the GCU detects that the generator speed has dropped to 0, it exits short-circuit protection mode and sends a command to the vehicle controller (VCU).

[0066] The range extender system of this embodiment can improve the protection against short circuit of the DC output busbar of the range extender, can effectively isolate the range extender system from the short circuit loop, and can achieve short circuit protection without the aid of an external circuit, thereby effectively protecting the range extender system.

[0067] In one embodiment, Figure 6This is a schematic diagram of the structure of a computer device provided in the fourth embodiment of the present invention. Figure 6 As shown, the computer device of this embodiment includes: at least one processor ( Figure 6 Only one is shown), a memory, and a computer program stored in the memory and executable on at least one processor, wherein when the processor executes the computer program, the steps in any of the above method embodiments are implemented.

[0068] The computer device may include, but is not limited to, a processor and a memory. It will be understood by those skilled in the art that Figure 6 The above is merely an example of a computer device and does not constitute a limitation on the computer device. The computer device may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, it may also include a network interface, a display screen, and an input device.

[0069] The processor may be a CPU, or other general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. A general-purpose processor may be a microprocessor, or any conventional processor.

[0070] The memory includes a readable storage medium, an internal memory, etc., wherein the internal memory can be the memory of a computer device, and the internal memory provides an environment for the operation of the operating system and computer-readable instructions in the readable storage medium. The readable storage medium can be the hard disk of the computer device, and in other embodiments, it can also be an external storage device of the computer device, for example, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the computer device. Furthermore, the memory can also include both the internal storage unit of the computer device and the external storage device. The memory is used to store the operating system, application programs, boot loaders (BootLoader), data, and other programs, such as the program code of the computer program. The memory can also be used to temporarily store data that has been output or is about to be output.

[0071] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other and are not used to limit the scope of protection of the present invention. The specific working process of the units and modules in the above-mentioned device can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, it can implement the steps of the above-mentioned method embodiment. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include at least: any entity or device capable of carrying computer program code, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0072] The present invention may implement all or part of the processes in the above-mentioned method embodiments, and may also be completed through a computer program product. When the computer program product runs on a computer device, the computer device can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0073] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0074] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the DC bus short-circuit protection control method in the above embodiment is implemented, for example Figure 2 Alternatively, when the computer program is executed by the processor, the functions of each module / unit in the embodiment of the DC bus short-circuit protection control device are realized, for example, Figure 3 The DC bus short-circuit protection control function shown in the figure will not be described here in detail to avoid repetition.

[0075] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, which can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0076] The present invention may implement all or part of the processes in the above-mentioned method embodiments, and may also be completed through a computer program product. When the computer program product runs on a computer device, the computer device can implement the steps in the above-mentioned method embodiments when executing the computer program product.

[0077] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0078] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0079] In the embodiments provided by the present invention, it should be understood that the disclosed apparatus / computer equipment and methods can be implemented in other ways. For example, the apparatus / computer equipment embodiments described above are merely illustrative. For example, the division of modules or units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0080] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0081] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A DC bus short-circuit protection control method for a range extender, characterized in that: The following steps are involved: Check whether the DC bus of the range extender has a short circuit fault; When a short circuit fault is detected in the DC bus of the range extender, the generator controller feeds back the short circuit fault status bit SC to the vehicle controller. When the vehicle controller determines that the short circuit fault status bit SC is valid, it controls the generator of the range extender to exit the power generation mode and activates the DC bus short circuit protection. The engine controller of the range extender receives the short circuit protection instruction to control the engine of the range extender to reduce the speed. The generator controller of the range extender receives the short circuit protection instruction to control the generator of the range extender to generate braking torque to accelerate the engine to stop rotation. The DC bus short-circuit protection control method further includes: After receiving the short-circuit protection instruction, the generator controller obtains the current speed of the generator in real time; When the current speed of the generator is greater than a preset high speed threshold value, the active short circuit protection mode is entered to control the generator of the range extender to generate a first braking torque; When the current speed of the generator is not greater than a preset high speed threshold value, the power device shutdown protection mode is entered, and the generator of the range extender is controlled to generate a second braking torque, which is less than the first braking torque.

2. The DC bus short-circuit protection control method according to claim 1, characterized in that: Entering the active short-circuit protection mode and controlling the generator of the range extender to generate the first braking torque includes: The upper arm switch tubes or the lower arm switch tubes of the generator controller are controlled to be fully turned on, so that the three-phase winding of the generator is actively short-circuited, so that the generator generates a first braking torque.

3. The DC bus short-circuit protection control method according to claim 1, characterized in that: Entering the power device shutdown protection mode and controlling the generator of the range extender to generate the second braking torque includes: The upper arm switch tubes and the lower arm switch tubes of the generator controller are controlled to be completely turned off, so that the generator generates a second braking torque lower than the first braking torque.

4. The DC bus short-circuit protection control method according to claim 1, characterized in that: Sending a short circuit protection instruction to the engine controller of the range extender to control the engine speed reduction of the range extender includes: After receiving the short-circuit protection instruction, the engine controller of the range extender generates a zero torque instruction to control the engine to reduce speed.

5. The DC bus short-circuit protection control method according to claim 1, characterized in that: Detecting whether a short circuit fault occurs in the DC bus of the range extender includes: The supporting capacitor voltage of the generator controller is acquired in real time. When it is detected that the supporting capacitor voltage is continuously less than or equal to a preset voltage threshold within a continuous preset time period, it is determined that a short circuit fault occurs on the DC bus.

6. A DC bus short-circuit protection control device for a range extender, characterized in that: The DC bus short-circuit protection control device is applied to the DC bus short-circuit protection control method according to any one of claims 1 to 5, and the DC bus short-circuit protection control device includes: a generator controller configured to detect whether a short circuit fault occurs in the DC bus of the range extender; when a short circuit fault is detected in the DC bus of the range extender, the controller sends a fault status signal to the vehicle controller and receives a short circuit protection instruction from the vehicle controller to control the generator of the range extender to generate a braking torque and accelerate the engine to stop rotation; The engine controller is used to receive a short-circuit protection instruction sent by the vehicle controller to control the engine speed reduction of the range extender.

7. The DC bus short-circuit protection control device according to claim 6, characterized in that: The generator controller is further configured to obtain the current speed of the generator in real time after receiving the short-circuit protection instruction; when the current speed of the generator is greater than a preset high speed threshold, control the generator of the range extender to generate a first braking torque; When the current speed of the generator is not greater than a preset high speed threshold value, the generator of the range extender is controlled to generate a second braking torque, where the second braking torque is less than the first braking torque.

8. A range extender system, characterized in that: The range extender system is applied to the DC bus short-circuit protection control method according to any one of claims 1 to 5, and the range extender system includes: An engine and an engine controller, wherein a control output of the engine controller is connected to a control input of the engine; A generator and a generator controller, wherein a control output end of the generator controller is connected to a control input end of the generator.

9. The range extender system according to claim 8, characterized in that: Also includes: The vehicle controller is configured to receive a fault status signal sent by the generator controller, determine that a short circuit fault has occurred in the DC bus according to the fault status signal, and send short circuit protection instructions to the engine controller and the generator controller respectively.

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