Battery short-circuit protection circuit, device and method

Abstract

The invention discloses a battery short-circuit protection circuit, device and method, and relates to the technical field of battery short-circuit protection, the battery short-circuit protection circuit comprises an acquisition circuit, an amplification circuit and a control circuit, the acquisition circuit is used for acquiring current of a battery power supply main loop and converting the current into a voltage signal for output, and the amplification circuit is used for amplifying and outputting the voltage signal; the control circuit is configured to obtain an amplified voltage signal output by the amplifying circuit, when the amplified voltage signal is larger than a reference voltage signal, the charging and discharging switching device is controlled to be switched off, the number of times starts to be recorded in an accumulated mode, and the charging and discharging switching device is controlled to be switched on after a first duration is preset; and after a second duration is preset, if the recording frequency reaches a preset value, controlling the charging and discharging switching device to be continuously switched off. By adopting the combined logic of delayed conduction and short circuit fault frequency judgment, the situation that a vehicle door and a vehicle window cannot be opened due to battery power supply loss caused by instant short circuit during collision can be greatly reduced, and then the survival rate of people in a vehicle can be greatly increased.

Description

Technical Field

[0001] This invention relates to the field of battery short-circuit protection technology, and in particular to a battery short-circuit protection circuit, device and method. Background Technology

[0002] Currently, most passenger cars use a 12V low-voltage system. When the engine is running, it drives the alternator to charge the battery and power electronic devices such as headlights, audio systems, air conditioning, power windows, and windshield wipers.

[0003] In the prior art, Chinese patent CN202111257430.8 discloses a hardware overcurrent protection system and method. This overcurrent protection system includes a voltage regulation circuit, a differential operational amplifier circuit, a voltage comparator circuit, a microprocessor, and an OR gate circuit. The differential operational amplifier circuit is electrically connected to the voltage regulation circuit. The voltage comparator circuit is electrically connected to the differential operational amplifier circuit and is used to compare the differential voltage signal after differential operation with a preset reference voltage and output a level signal. The microprocessor is electrically connected to the voltage comparator circuit and is used to identify the level signal and output a first drive signal. The OR gate circuit is electrically connected to the voltage comparator circuit and is used to identify the level signal and output a second drive signal to the relay shutdown drive circuit. The OR gate circuit is also electrically connected to the microprocessor and is used to send the first drive signal to the relay shutdown drive circuit. Therefore, the overcurrent protection method is entirely implemented through hardware circuitry, with a fast response time. In the event of an external short circuit, it can disconnect the charging / discharging MOS in approximately 1ms, protecting the charging / discharging MOS and the 12V battery.

[0004] However, this patented method will also directly disconnect the charging and discharging MOS when encountering a momentary short circuit during a collision. In other words, this patented method has difficulty distinguishing between a momentary short circuit (such as a collision) and a real short circuit fault, resulting in the loss of power supply to the doors and windows during a momentary short circuit. Especially during a vehicle collision, a momentary short circuit will prevent the doors and windows from opening, making it easy for passengers to be trapped inside the vehicle and reducing the survival rate of the people inside the vehicle. Summary of the Invention

[0005] This invention provides a battery short-circuit protection circuit, device, and method to solve the technical problem in the related art that existing battery short-circuit protection circuits are unable to distinguish between instantaneous short circuits and actual short circuits during collisions, resulting in the inability to open vehicle doors and windows after a collision.

[0006] Firstly, a battery short-circuit protection circuit is provided, including: The acquisition circuit is used to acquire the current of the main circuit powered by the battery and convert it into a voltage signal output. An amplifier circuit is connected to the acquisition circuit, and the amplifier circuit is used to amplify and output the voltage signal input to the acquisition circuit; A control circuit, connected to the amplifier circuit and the charge / discharge switching device of the battery power supply main circuit, is configured as follows: The amplified voltage signal output by the amplifier circuit is obtained. When the amplified voltage signal is greater than the reference voltage signal, the charge and discharge switch device is controlled to open and the number of times is recorded in an accumulative manner. After a preset first time, the charge and discharge switch device is controlled to turn on. After a second preset duration, if the number of recorded times reaches the preset value, the charging and discharging switch will be continuously disconnected.

[0007] In some embodiments, the control circuit includes a controller and a driver. The step of acquiring the amplified voltage signal output by the amplification circuit, and when the amplified voltage signal is greater than a reference voltage signal, controlling the charge / discharge switch to open and starting to record the number of times in an accumulative manner, and then controlling the charge / discharge switch to turn on again after a preset first duration, includes: The driver acquires the amplified voltage signal output by the amplifier circuit and determines whether the amplified voltage signal is greater than the reference voltage signal. If so, the driver controls the charge / discharge switch to open and sends a short-circuit fault signal to the controller; The controller starts recording the number of times in an incremental manner, and after a preset first duration, sends a command to the driver to cause the driver to control the charging and discharging switching device to turn on.

[0008] In some embodiments, the driver uses a 2E4D10 chip.

[0009] In some embodiments, the acquisition circuit includes a shunt connected to the amplifier circuit. The shunt is used to acquire the current of the battery-powered main circuit and convert it into a voltage signal, which is then output to the amplifier circuit.

[0010] In some embodiments, the amplification circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first operational amplifier, and a second operational amplifier; The first end of the first resistor and the first end of the second resistor are respectively connected to the two output terminals of the shunt. The second end of the first resistor is connected to the negative input terminal of the first operational amplifier, and the second end of the second resistor is connected to the positive input terminal of the first operational amplifier. The first end of the third resistor is connected to the negative input terminal of the first operational amplifier, and the second end of the third resistor is connected to the output terminal of the first operational amplifier and serves as the output terminal of the amplifier circuit, which is connected to the control circuit. The first end of the fourth resistor is connected to the positive input terminal of the first operational amplifier, and the second end of the fourth resistor is connected to the negative input terminal and the output terminal of the second operational amplifier. The first end of the fifth resistor is connected to the power supply, the second end of the fifth resistor is connected to the first end of the sixth resistor and the positive input terminal of the second operational amplifier, and the second end of the sixth resistor is grounded.

[0011] In some embodiments, the battery short-circuit protection circuit further includes: A reference voltage circuit, which is connected to the control circuit, is used to output a reference voltage signal to the control circuit.

[0012] In some embodiments, the reference voltage circuit includes a seventh resistor and an eighth resistor, a first terminal of the seventh resistor is connected to a power supply, a second terminal of the seventh resistor is connected to the first terminal of the eighth resistor and the control circuit, and the second terminal of the eighth resistor is grounded.

[0013] Secondly, a battery short-circuit protection device is provided, including the aforementioned battery short-circuit protection circuit.

[0014] Thirdly, a battery short-circuit protection method is provided, including the following steps: The amplified voltage signal output by the amplifier circuit is obtained. When the amplified voltage signal is greater than the reference voltage signal, the charge and discharge switch device is controlled to open and the number of times is recorded in an accumulative manner. After a preset first time, the charge and discharge switch device is controlled to turn on. After a second preset duration, if the number of recorded times reaches the preset value, the charging and discharging switch will be continuously disconnected.

[0015] In some embodiments, the step of acquiring the amplified voltage signal output by the amplification circuit, when the amplified voltage signal is greater than the reference voltage signal, controls the charge / discharge switch to open and starts recording the number of times in an accumulative manner, and then controls the charge / discharge switch to turn on again after a preset first duration, includes: The driver acquires the amplified voltage signal output by the amplifier circuit and determines whether the amplified voltage signal is greater than the reference voltage signal. If so, the driver controls the charge / discharge switch to open and sends a short-circuit fault signal to the controller; The controller starts recording the number of times in an incremental manner, and after a preset first duration, sends a command to the driver to cause the driver to control the charging and discharging switching device to turn on.

[0016] The beneficial effects of the technical solution provided by this invention include: This invention provides a battery short-circuit protection circuit, device, and method. When a short-circuit fault occurs in the main battery power supply circuit (the amplified voltage signal is greater than the reference voltage signal), the battery short-circuit protection circuit does not directly and continuously disconnect the charging and discharging switch of the main battery power supply circuit. Instead, it controls the charging and discharging switch to turn on after a preset first time period. Within a preset second time period, if the number of recorded times reaches a preset value, it is determined that the main battery power supply circuit is truly short-circuited rather than momentarily short-circuited, and then the charging and discharging switch is continuously disconnected. This combination of delay and multiple judgments can greatly reduce the situation where the car doors and windows cannot be opened due to the loss of battery power during a collision due to a momentary short circuit, thereby greatly improving the survival rate of the occupants. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic block diagram of a battery short-circuit protection circuit provided in an embodiment of the present invention; Figure 2 Another schematic diagram of a battery short-circuit protection circuit provided in an embodiment of the present invention; Figure 3 A timing logic diagram of a battery short-circuit protection circuit corresponding to a real short circuit is provided in an embodiment of the present invention; Figure 4 A timing logic diagram of a battery short-circuit protection circuit corresponding to an instantaneous short circuit is provided in an embodiment of the present invention; Figure 5 A circuit diagram of an amplifier circuit provided in an embodiment of the present invention; Figure 6 A circuit diagram of a reference voltage circuit provided for an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] This invention provides a battery short-circuit protection circuit that solves the technical problem that existing battery short-circuit protection circuits cannot distinguish between instantaneous short circuits and actual short circuits after a collision, resulting in the inability to open vehicle doors and windows after a collision.

[0021] See Figure 1 As shown, this embodiment of the invention provides a battery short-circuit protection circuit, including: a data acquisition circuit, an amplification circuit, and a control circuit.

[0022] The acquisition circuit is used to acquire the current of the battery-powered main circuit and convert it into a voltage signal for output. The amplification circuit is connected to the acquisition circuit and is used to amplify the voltage signal for output.

[0023] The control circuit is connected to the amplifier circuit and the charge / discharge switching device of the battery power supply main circuit, and the control circuit is configured as follows: The amplified voltage signal output by the amplifier circuit is obtained. When the amplified voltage signal is greater than the reference voltage signal, the charge and discharge switch device is controlled to open and the number of times is recorded in an accumulative manner. After a preset first time, the charge and discharge switch device is controlled to turn on. After a second preset duration, if the number of recorded times reaches the preset value, the charging and discharging switch will be continuously disconnected.

[0024] The battery short-circuit protection circuit in this embodiment of the invention, when a short-circuit fault occurs in the main battery power supply circuit (the amplified voltage signal is greater than the reference voltage signal), does not directly and continuously disconnect the charging and discharging switch device of the main battery power supply circuit. Instead, it controls the charging and discharging switch device to conduct after a preset first time period. Furthermore, within a preset second time period, if the number of recorded occurrences reaches a preset value, indicating a genuine short circuit rather than a momentary short circuit in the main battery power supply circuit, it then controls the charging and discharging switch device to continuously disconnect. This combination of delayed conduction and short-circuit fault count determination logic can significantly reduce the likelihood of doors and windows being unable to open due to momentary short circuits and loss of battery power during a collision, thereby greatly improving the survival rate of occupants. In addition, while controlling the charging and discharging switch device to continuously disconnect after the preset number of recorded occurrences reaches the preset value, it can also report the actual short-circuit fault to the vehicle display, alerting the driver of the short-circuit fault, or issue a flashing alarm to the driver.

[0025] As an optional implementation, in one embodiment of the invention, see [link to relevant documentation]. Figure 2 As shown, the control circuit includes a controller and a driver. The step involves acquiring the amplified voltage signal output by the amplification circuit. When the amplified voltage signal is greater than the reference voltage signal, the charge / discharge switch is controlled to open and the number of counts is started in an accumulative manner. After a preset first duration, the charge / discharge switch is controlled to turn on again. This includes: The driver acquires the amplified voltage signal output by the amplifier circuit and determines whether the amplified voltage signal is greater than the reference voltage signal. If so, the driver controls the charge / discharge switch to open and sends a short-circuit fault signal to the controller; The controller starts recording the number of times in an incremental manner, and after a preset first duration, sends a command to the driver to cause the driver to control the charging and discharging switching device to turn on.

[0026] Specifically, the driver can use a 2E4D10 chip. The 2E4D10 chip integrates a comparator. The amplified voltage signal output from the amplifier circuit is input to the comparator inside the 2E4D10 chip. The comparator inside the 2E4D10 chip compares the amplified voltage signal with a preset reference voltage signal. When the amplified voltage signal is greater than the reference voltage signal (i.e., the current in the main circuit of the battery power supply is greater than the short-circuit current threshold), the driver turns off the charging and discharging switching device (MOSFET) through the GA, SA, GB, and SB pins. At the same time, it changes the output state of the INT, DG0, and DG1 pins (short-circuit fault signal). The controller MCU detects the state of the INT, DG0, and DG1 pins in real time. When a short-circuit fault is detected, the controller MCU outputs EN=0 and starts the internal timer T1 (preset first duration). After T1 ends, the controller MCU outputs EN=1, INA=1, and INB=1, restarting the charging and discharging switching device. After a second preset duration T2, if the number of recorded times reaches a preset value N, it is determined that the main circuit of the battery power supply is truly short-circuited, and the charging and discharging switch is continuously disconnected and not restored.

[0027] The following example further illustrates this: The preset duration T1 is 10 seconds, the preset duration T2 is 40 seconds, and the preset value N is 3. See also... Figure 3 As shown, if a true short circuit (sustained short circuit fault) occurs, three short circuit faults can be recorded within 40 seconds. See also... Figure 4 As shown, if a momentary short circuit occurs, only one short circuit fault will be recorded within 40 seconds. Figure 3 and Figure 4 T0 in the equation represents the short-circuit trigger disconnection time (in milliseconds) plus the detection time (in tens of milliseconds) during which the controller detects the short circuit. Additionally, after the second preset duration, all recorded counts are reset to zero.

[0028] As an optional implementation, in one embodiment of the invention, see [link to relevant documentation]. Figure 2As shown, the acquisition circuit includes a shunt, which is connected to the amplifier circuit. The shunt is used to acquire the current of the battery-powered main circuit and convert it into a voltage signal (differential voltage signal) which is then output to the amplifier circuit. The shunt has advantages such as high measurement accuracy, fast response speed, simple structure, and low cost.

[0029] As an optional implementation, in one embodiment of the invention, see [link to relevant documentation]. Figure 5 As shown, the amplifier circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first operational amplifier U1, and a second operational amplifier U2.

[0030] The first end of the first resistor R1 and the first end of the second resistor R2 are respectively connected to the two output terminals of the shunt. The second end of the first resistor R1 is connected to the negative input terminal of the first operational amplifier U1, and the second end of the second resistor R2 is connected to the positive input terminal of the first operational amplifier U1. The first end of the third resistor R3 is connected to the negative input terminal of the first operational amplifier U1, and the second end of the third resistor R3 is connected to the output terminal of the first operational amplifier U1 and serves as the output terminal of the amplifier circuit, which is connected to the control circuit (driver). The first end of the fourth resistor R4 is connected to the positive input terminal of the first operational amplifier U1, and the second end of the fourth resistor R4 is connected to the negative input terminal and the output terminal of the second operational amplifier U2. The first end of the fifth resistor R5 is connected to the power supply VDD, the second end of the fifth resistor is connected to the first end of the sixth resistor R6 and the positive input terminal of the second operational amplifier U2, and the second end of the sixth resistor R6 is grounded.

[0031] Amplified voltage signal V 放 =Vi·(R3 / R1)+VDD·(R6 / (R5+R6)), where VDD can be taken as 5.4V, and Vi is the differential voltage between the two output terminals of the shunt. If the first terminal of the second resistor R2 is grounded, Vi is the voltage at the first terminal of the first resistor R1, with an amplification factor R3 / R1=10. Assuming the short-circuit current threshold of the battery-powered main circuit is 1000A, and the resistance of the shunt is 100uΩ, then Vi=1000A·100uΩ=0.1V.

[0032] As an optional implementation, in one embodiment of the invention, see [link to relevant documentation]. Figure 2 As shown, the battery short-circuit protection circuit further includes a reference voltage circuit, which is connected to the control circuit and is used to output a reference voltage signal to the control circuit.

[0033] Further, see Figure 6 As shown, the reference voltage circuit includes a seventh resistor R7 and an eighth resistor R8. The first end of the seventh resistor R7 is connected to the power supply VDD, the second end of the seventh resistor R7 is connected to the first end of the eighth resistor R8 and the control circuit (driver), and the second end of the eighth resistor R8 is grounded.

[0034] The values ​​of the seventh resistor R7 and the eighth resistor R8 are: V 分 =5.4·(R8 / (R7+R8))=Vi·(R3 / R1)+5.4·R6 / (R5+R6)), or assuming the short-circuit current threshold of the main circuit of battery power supply is 1000A, R8 / (R7+R8)=3.712 / 5.4, the voltage division ratio of the seventh resistor R7 and the eighth resistor R8 can be adjusted according to actual needs.

[0035] This invention also provides a battery short-circuit protection device, including the aforementioned battery short-circuit protection circuit.

[0036] This invention also provides a battery short-circuit protection method, comprising the following steps: The amplified voltage signal output by the amplifier circuit is obtained. When the amplified voltage signal is greater than the reference voltage signal, the charge and discharge switch device is controlled to open and the number of times is recorded in an accumulative manner. After a preset first time, the charge and discharge switch device is controlled to turn on. After a second preset duration, if the number of recorded times reaches the preset value, the charging and discharging switch will be continuously disconnected.

[0037] As an optional implementation, in one embodiment of the invention, the step of acquiring the amplified voltage signal output by the amplification circuit, controlling the charge / discharge switch to disconnect and starting to record the number of times in an accumulative manner when the amplified voltage signal is greater than the reference voltage signal, and then controlling the charge / discharge switch to turn on again after a preset first duration, includes: The driver acquires the amplified voltage signal output by the amplifier circuit and determines whether the amplified voltage signal is greater than the reference voltage signal. If so, the driver controls the charge / discharge switch to open and sends a short-circuit fault signal to the controller; The controller starts recording the number of times in an incremental manner, and after a preset first duration, sends a command to the driver to cause the driver to control the charging and discharging switching device to turn on.

[0038] In the description of this invention, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0039] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0040] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the invention herein.

Claims

1. A battery short-circuit protection circuit, characterized in that, include: The acquisition circuit is used to acquire the current of the main circuit powered by the battery and convert it into a voltage signal output. An amplifier circuit is connected to the acquisition circuit, and the amplifier circuit is used to amplify and output the voltage signal input to the acquisition circuit; A control circuit, connected to the amplifier circuit and the charge / discharge switching device of the battery power supply main circuit, is configured as follows: The amplified voltage signal output by the amplifier circuit is obtained. When the amplified voltage signal is greater than the reference voltage signal, the charge and discharge switch device is controlled to open and the number of times is recorded in an accumulative manner. After a preset first time, the charge and discharge switch device is controlled to turn on. After a second preset duration, if the number of recorded times reaches the preset value, the charging and discharging switch will be continuously disconnected.

2. The battery short-circuit protection circuit according to claim 1, characterized in that, The control circuit includes a controller and a driver. It acquires the amplified voltage signal output by the amplification circuit. When the amplified voltage signal is greater than the reference voltage signal, it controls the charge / discharge switch to open and starts recording the number of times in an accumulative manner. After a preset first duration, it controls the charge / discharge switch to turn on again. This includes: The driver acquires the amplified voltage signal output by the amplifier circuit and determines whether the amplified voltage signal is greater than the reference voltage signal. If so, the driver controls the charge / discharge switch to open and sends a short-circuit fault signal to the controller; The controller starts recording the number of times in an incremental manner, and after a preset first duration, sends a command to the driver to cause the driver to control the charging and discharging switching device to turn on.

3. The battery short-circuit protection circuit according to claim 2, characterized in that: The driver uses a 2E4D10 chip.

4. The battery short-circuit protection circuit according to claim 1, characterized in that: The acquisition circuit includes a shunt, which is connected to the amplifier circuit. The shunt is used to acquire the current of the battery-powered main circuit and convert it into a voltage signal, which is then output to the amplifier circuit.

5. The battery short-circuit protection circuit according to claim 4, characterized in that: The amplifier circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first operational amplifier, and a second operational amplifier; The first end of the first resistor and the first end of the second resistor are respectively connected to the two output terminals of the shunt. The second end of the first resistor is connected to the negative input terminal of the first operational amplifier, and the second end of the second resistor is connected to the positive input terminal of the first operational amplifier. The first end of the third resistor is connected to the negative input terminal of the first operational amplifier, and the second end of the third resistor is connected to the output terminal of the first operational amplifier and serves as the output terminal of the amplifier circuit, which is connected to the control circuit. The first end of the fourth resistor is connected to the positive input terminal of the first operational amplifier, and the second end of the fourth resistor is connected to the negative input terminal and the output terminal of the second operational amplifier. The first end of the fifth resistor is connected to the power supply, the second end of the fifth resistor is connected to the first end of the sixth resistor and the positive input terminal of the second operational amplifier, and the second end of the sixth resistor is grounded.

6. The battery short-circuit protection circuit according to claim 1, characterized in that, Also includes: A reference voltage circuit, which is connected to the control circuit, is used to output a reference voltage signal to the control circuit.

7. The battery short-circuit protection circuit according to claim 6, characterized in that: The reference voltage circuit includes a seventh resistor and an eighth resistor. The first end of the seventh resistor is connected to the power supply, the second end of the seventh resistor is connected to the first end of the eighth resistor and the control circuit, and the second end of the eighth resistor is grounded.

8. A battery short-circuit protection device, characterized in that, Includes the battery short-circuit protection circuit as described in any one of claims 1-7.

9. A battery short-circuit protection method, using the battery short-circuit protection circuit of claim 1, characterized in that, Includes the following steps: The amplified voltage signal output by the amplifier circuit is obtained. When the amplified voltage signal is greater than the reference voltage signal, the charge and discharge switch device is controlled to open and the number of times is recorded in an accumulative manner. After a preset first time, the charge and discharge switch device is controlled to turn on. After a second preset duration, if the number of recorded times reaches the preset value, the charging and discharging switch will be continuously disconnected.

10. The battery short-circuit protection method according to claim 9, characterized in that, The process involves acquiring the amplified voltage signal output by the amplification circuit. When the amplified voltage signal is greater than the reference voltage signal, the charging / discharging switch is controlled to open and the number of times is recorded in an accumulative manner. After a preset first duration, the charging / discharging switch is then controlled to turn on again. This includes: The driver acquires the amplified voltage signal output by the amplifier circuit and determines whether the amplified voltage signal is greater than the reference voltage signal. If so, the driver controls the charge / discharge switch to open and sends a short-circuit fault signal to the controller; The controller starts recording the number of times in an incremental manner, and after a preset first duration, sends a command to the driver to cause the driver to control the charging and discharging switching device to turn on.

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