A battery protection method based on BMS sleep and low current identification and detection

Abstract

The present invention discloses a battery protection method based on the identification and detection of small currents in a BMS dormant state, which relates to the field of circuit technology and includes: forming an installation point for a sampling resistor in the circuit of the BMS and performing structural setting of the sampling resistor; presetting the BMS; obtaining the interference ratio of the BMS circuit to the sampling resistor; when the current of the BMS charge and discharge does not exceed the wake-up current detection threshold, the sampling resistor amplifies the BMS charge and discharge current, wakes up the MCU, and the MCU performs battery protection; when the sampling resistor amplifies the BMS charge and discharge current, it uses the interference ratio to amplify the current filter signal. By forming the installation point for the sampling resistor, performing structural setting of the sampling resistor, and obtaining the interference ratio of the sampling resistor, the induced current signal can be removed according to the actual situation, ensuring that a small current will inevitably wake up the MCU, thereby ensuring the protection of the battery.

Description

Technical Field

[0001] The present invention relates to the field of circuit technology, and in particular to a battery protection method based on BMS dormant low current identification and detection. Background Art

[0002] A BMS typically consists of two main chips: a front-end battery management chip, called the BMS front end, and an MCU, responsible for communication and event processing. When the system enters sleep mode, both the BMS front end and the MCU enter a low-power mode. The system only detects charger insertion and performs general functional checks, ignoring low-current charging and discharging. Only when the host computer wakes up via the communication line does the MCU enter a state to protect the battery. During this time, low currents are ignored during charging and discharging, which can damage the battery. If a large load is connected and the discharge wake-up current detection threshold is reached, the BMS front end chip wakes itself, thereby waking up the main MCU for protection. However, if a low-current load is connected, the BMS front end chip will not wake up due to the low voltage signal, and thus the MCU. This will cause the battery to enter an abnormal state and potentially discharge to 0V, damaging the battery. Therefore, it is necessary to amplify the small current and wake up the MCU through external termination. However, since there are multiple lines in the BMS, the nearby wires will generate induced currents on each other, which will interfere with the small charging and discharging currents, thereby affecting the control of current amplification. It may be impossible to wake up the MCU in time, affecting the protection of the battery. Summary of the Invention

[0003] In order to solve the above technical problems, a battery protection method based on BMS dormant small current identification and detection is provided. This technical solution solves the problems raised in the above background technology.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0005] A battery protection method based on BMS dormant low current identification and detection, comprising:

[0006] Form the installation points of the sampling resistor in the BMS circuit and set the structure of the sampling resistor;

[0007] Pre-set the BMS. The interrupt condition of the MCU's I / O port is that the current passing through the I / O port is greater than the preset value. Connect the sampling resistor to the BMS circuit according to the setting of the installation point.

[0008] Obtain the interference ratio of the BMS circuit to the sampling resistor;

[0009] When the BMS charging and discharging current is greater than the wake-up current detection threshold, the BMS front end is awakened, the BMS front end wakes up the MCU, and the MCU performs battery protection;

[0010] When the BMS charge and discharge current does not exceed the wake-up current detection threshold, the sampling resistor amplifies the BMS charge and discharge current, reaching the interrupt condition of the MCU's I / O port. The I / O port is connected to the MCU, and the MCU wakes up through an external interrupt, and the MCU performs battery protection.

[0011] When the sampling resistor amplifies the BMS charging and discharging current, it uses the interference ratio to remove the interference of the actual current signal to obtain a current filter signal, and then amplifies the current filter signal.

[0012] Preferably, forming the installation point of the sampling resistor in the BMS circuit includes the following steps:

[0013] Obtain at least one wire directly connected to the MCU in the BMS circuit, obtain the current value of the wire when the BMS is charging and discharging, select the wire with the largest current value as the target wire, and evenly select at least one sampling point on the target wire;

[0014] The BMS uses a preset current for charging, which is direct current. A first closed circuit and a second closed circuit are set at a sampling point. The first closed circuit and the second closed circuit are not connected to the BMS circuit. The first closed circuit and the second closed circuit are of the same size. The sampling point is located at the center of the first closed circuit and the second closed circuit. The distance between the first closed circuit and the second closed circuit is a preset distance.

[0015] Acquire a first induced current signal in the first closed circuit, and acquire a second induced current signal in the second closed circuit;

[0016] When the first induced current signal and the second induced current signal are equal, the sampling point where the first induced current signal and the second induced current signal are obtained is used as the installation point of the sampling resistor;

[0017] When there is no sampling point that makes the first induced current signal equal to the second induced current signal, a sampling point is added at the midpoint of the adjacent sampling points. After the addition, if there is a sampling point that makes the first induced current signal equal to the second induced current signal, the addition is stopped; if not, the addition of sampling points continues.

[0018] Preferably, the structural setting of the sampling resistor includes the following steps:

[0019] Obtain the maximum value of the induced current generated by the BMS circuit on the sampling resistor. Based on historical data, obtain the minimum current value during the charging and discharging of the BMS circuit as the characteristic current.

[0020] The sampling resistor is composed of a first inductor and a second inductor, the first inductor and the second inductor are not connected, and the distance between the first inductor and the second inductor is a preset distance;

[0021] Both ends of the first inductor are provided with first pins, and both ends of the second inductor are provided with second pins;

[0022] Setting the number of turns of the coil of the first inductor to a preset number of turns, where the preset number of turns is any value less than 10;

[0023] Obtain the absolute value of the difference between the characteristic current and the maximum value of the induced current as the target value;

[0024] The preset number of turns is divided by the target value and multiplied by the preset value to obtain the preliminary number of turns, the preliminary number of turns is rounded to obtain the target number of turns, and the number of turns of the coil of the second inductor is set to the target number of turns.

[0025] Preferably, the pre-setting of the BMS includes the following steps:

[0026] The front-end battery management chip in the BMS is used as the BMS front end, and the chip responsible for communication and event processing in the BMS is used as the MCU;

[0027] Obtain the wake-up current detection threshold of the BMS front end. The BMS charging and discharging current flows through the sampling resistor. The sampling resistor is connected in series with the I / O port, and the I / O port is connected to the MCU as a pin.

[0028] Preferably, the step of connecting the sampling resistor to the BMS circuit according to the setting of the installation point includes the following steps:

[0029] Divide the target wire into two parts: the first wire and the second wire. The dividing point is the installation point of the sampling resistor. The distance from the second wire to the MCU is smaller than the distance from the first wire to the MCU.

[0030] Connecting the first inductor to the first wire through first pins at both ends of the first inductor, and connecting the second inductor to the second wire through second pins at both ends of the second inductor;

[0031] The installation point is located at the center of the first inductor and the second inductor, and the distance between the first inductor and the second inductor is a preset distance.

[0032] Preferably, obtaining the interference ratio of the BMS circuit to the sampling resistor includes the following steps:

[0033] The BMS uses a preset current for charging and calculates the sample current value at the second inductor based on the resistance distribution of the BMS circuit;

[0034] The actual current value is measured at the second inductor, and the sample current value is subtracted from the actual current value and divided by the actual current value to obtain the interference ratio.

[0035] Preferably, the step of measuring the actual current value at the second inductor comprises the following steps:

[0036] Based on historical measurement data, obtain the average error rate of small current measurement;

[0037] measuring at least one test current value at the second inductor, and using a maximum value and a minimum value of the at least one test current value as endpoints to form a current value interval;

[0038] uniformly selecting at least one identification point in the current value interval;

[0039] Calculating the error ratio of at least one test current value relative to the identification point respectively, and taking an average of the at least one error ratio to obtain an actual error rate;

[0040] The value of the identification point corresponding to the actual error rate that has the smallest difference from the average error rate is taken as the actual current value.

[0041] Preferably, the step of performing interference removal processing on the actual current signal to obtain a current filtered signal comprises the following steps:

[0042] Acquire an actual current signal at the first inductor, and multiply the actual current signal by the interference ratio to obtain a current interference signal;

[0043] Decomposing the actual current signal using Fourier transform to obtain at least one actual basic signal;

[0044] Decomposing the current interference signal using Fourier transform to obtain at least one basic interference signal;

[0045] Deleting the actual basic signal that is equal to the interfering basic signal;

[0046] The at least one actual basic signal after deletion is combined using inverse Fourier transform to obtain a current filtering signal.

[0047] Preferably, the step of obtaining the actual current signal at the first inductor comprises the following steps:

[0048] measuring at least one test current signal at the first inductor, taking one of the at least one test current signal as a current signal to be verified, and taking the remaining test current signal as a non-verification current signal;

[0049] Calculate the average forward current of the current signal to be verified in one cycle as the value to be verified;

[0050] Calculate the average value of the forward current of the non-verification current signal in one cycle as the non-verification value;

[0051] Calculate the error ratio of at least one non-verified value relative to the value to be verified and take the average to obtain the ratio to be verified;

[0052] After the current signal to be verified traverses the test current signal, the current signal to be verified corresponding to the ratio to be verified with the smallest difference from the average error rate is taken as the actual current signal.

[0053] Preferably, the amplifying process of the current filter signal includes the following steps:

[0054] After the current filter signal flows through the sampling resistor, it is amplified.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] By forming the installation point of the sampling resistor, setting the structure of the sampling resistor, obtaining the interference ratio of the sampling resistor and obtaining the current filter signal, the interference induced current signal generated by the BMS can be determined at the sampling resistor, and then the induced current signal can be removed according to the actual situation, and the current signal after the interference is removed can be amplified. Due to the structural setting of the sampling resistor, it is ensured that the current signal after the interference is removed can be amplified to the extent of triggering the interrupt condition of the MCU's I / O port, thereby ensuring that a small current will inevitably wake up the MCU, thereby ensuring the protection of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 Schematic diagram of the process of the battery protection method based on BMS dormant low current identification and detection of the present invention;

[0058] Figure 2 This is a flow chart of forming the installation points of the sampling resistor in the BMS circuit of the present invention;

[0059] Figure 3 A schematic diagram of the flow chart for the structural arrangement of the sampling resistor according to the present invention;

[0060] Figure 4 This is a schematic diagram of the process of pre-setting the BMS according to the present invention;

[0061] Figure 5 This is a flow chart of connecting the sampling resistor to the BMS circuit according to the setting of the installation point of the present invention;

[0062] Figure 6 This is a flow chart of obtaining the interference ratio of the BMS circuit to the sampling resistor according to the present invention;

[0063] Figure 7This is a schematic diagram of a process for measuring and obtaining an actual current value at a second inductor according to the present invention;

[0064] Figure 8 This is a flow chart of the present invention for performing interference removal processing on an actual current signal to obtain a current filtering signal;

[0065] Figure 9 This is a schematic diagram of the process of obtaining an actual current signal at a first inductor according to the present invention. DETAILED DESCRIPTION

[0066] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are merely examples, and those skilled in the art may conceive of other obvious variations.

[0067] Reference Figure 1 As shown, a battery protection method based on BMS dormant low current identification and detection includes:

[0068] Form the installation points of the sampling resistor in the BMS circuit and set the structure of the sampling resistor;

[0069] Pre-set the BMS. The interrupt condition of the MCU's I / O port is that the current passing through the I / O port is greater than the preset value. Connect the sampling resistor to the BMS circuit according to the setting of the installation point.

[0070] Obtain the interference ratio of the BMS circuit to the sampling resistor;

[0071] When the BMS charging and discharging current is greater than the wake-up current detection threshold, the BMS front end is awakened, the BMS front end wakes up the MCU, and the MCU performs battery protection;

[0072] When the BMS charge and discharge current does not exceed the wake-up current detection threshold, the sampling resistor amplifies the BMS charge and discharge current, reaching the interrupt condition of the MCU's I / O port. The I / O port is connected to the MCU, and the MCU wakes up through an external interrupt, and the MCU performs battery protection.

[0073] When the sampling resistor amplifies the BMS charging and discharging current, it uses the interference ratio to remove the interference of the actual current signal to obtain a current filter signal, and then amplifies the current filter signal.

[0074] In this solution, battery protection is mainly achieved through the control processing of the MCU, and two methods are used to protect the battery. When the charge and discharge current is large, the BMS front end is awakened, the BMS front end wakes up the MCU, and the MCU performs battery protection. When the charge and discharge current is small, the MCU is awakened by external interruption through the interrupt setting of the I / O port. The interrupt condition of the I / O port is set here, and the interrupt of the I / O port can be set through the code. There are no special requirements for the preset value. You only need to take any value within the current allowable range of the I / O port. For the convenience of detection, the value is usually as large as possible. Otherwise, the error impact will become larger during identification.

[0075] Reference Figure 2 As shown, forming the installation point of the sampling resistor in the BMS circuit includes the following steps:

[0076] Obtain at least one wire directly connected to the MCU in the BMS circuit, obtain the current value of the wire when the BMS is charging and discharging, select the wire with the largest current value as the target wire, and evenly select at least one sampling point on the target wire;

[0077] The BMS uses a preset current for charging, which is direct current. A first closed circuit and a second closed circuit are set at a sampling point. The first closed circuit and the second closed circuit are not connected to the BMS circuit. The first closed circuit and the second closed circuit are of the same size. The sampling point is located at the center of the first closed circuit and the second closed circuit. The distance between the first closed circuit and the second closed circuit is a preset distance.

[0078] Acquire a first induced current signal in the first closed circuit, and acquire a second induced current signal in the second closed circuit;

[0079] When the first induced current signal and the second induced current signal are equal, the sampling point where the first induced current signal and the second induced current signal are obtained is used as the installation point of the sampling resistor;

[0080] When there is no sampling point that makes the first induced current signal equal to the second induced current signal, a sampling point is added at the midpoint of the adjacent sampling points. After the addition, if there is a sampling point that makes the first induced current signal equal to the second induced current signal, the addition is stopped; if not, the addition of sampling points continues.

[0081] The sampling resistor is set at a certain position in the BMS circuit. For the sake of detection accuracy, a position with larger current is selected as much as possible. At the same time, since the sampling resistor needs to trigger the MCU, it needs to be selected on the wire directly connected to it, so that the current amplified by the sampling resistor will directly enter the MCU and complete the wake-up through the interruption of the I / O port. Since the BMS circuit will generate an induced current on the sampling resistor during charging and discharging, the different positions of the sampling resistor will lead to different interference induced currents. Therefore, for the convenience of subsequent processing, the position of the sampling resistor needs to be determined. The position of the sampling resistor determined here satisfies the equality of the first induced current signal and the second induced current signal in the first closed circuit and the second closed circuit. According to the subsequent installation method, it can be known that the induced current of the first inductor and the second inductor in the BMS circuit is consistent. Therefore, it is convenient to perform interference removal processing on the actual current signal.

[0082] Reference Figure 3 As shown, the structural setting of the sampling resistor includes the following steps:

[0083] Obtain the maximum value of the induced current generated by the BMS circuit on the sampling resistor. Based on historical data, obtain the minimum current value during the charging and discharging of the BMS circuit as the characteristic current.

[0084] The sampling resistor is composed of a first inductor and a second inductor, the first inductor and the second inductor are not connected, and the distance between the first inductor and the second inductor is a preset distance;

[0085] Both ends of the first inductor are provided with first pins, and both ends of the second inductor are provided with second pins;

[0086] Setting the number of turns of the coil of the first inductor to a preset number of turns, where the preset number of turns is any value less than 10;

[0087] Obtain the absolute value of the difference between the characteristic current and the maximum value of the induced current as the target value;

[0088] The preset number of turns is divided by the target value and multiplied by the preset value to obtain the preliminary number of turns, the preliminary number of turns is rounded to obtain the target number of turns, and the number of turns of the coil of the second inductor is set to the target number of turns.

[0089] The sampling resistor mainly amplifies the current. It is necessary to ensure that the small current is amplified to a value greater than the preset value, thereby completing the interruption of the I / O port and waking up the MCU. Since the interference will be removed during amplification, when setting the number of turns of the second inductor, it is not calculated based on the characteristic current, but based on the current after the interference is removed. Therefore, the absolute value of the difference between the characteristic current and the maximum value of the induced current is used as the target value, and the target value is used to calculate the number of preliminary turns. However, since the number of preliminary turns may be a decimal, it needs to be rounded. It should be noted that the maximum value of the induced current is generated by charging and discharging, so it will be smaller than the charging and discharging current.

[0090] Reference Figure 4 As shown, pre-setting the BMS includes the following steps:

[0091] The front-end battery management chip in the BMS is used as the BMS front end, and the chip responsible for communication and event processing in the BMS is used as the MCU;

[0092] Obtain the wake-up current detection threshold of the BMS front end. The BMS charging and discharging current flows through the sampling resistor. The sampling resistor is connected in series with the I / O port, and the I / O port is connected to the MCU as a pin.

[0093] Reference Figure 5 As shown in the figure, connecting the sampling resistor to the BMS circuit according to the installation point setting includes the following steps:

[0094] Divide the target wire into two parts: the first wire and the second wire. The dividing point is the installation point of the sampling resistor. The distance from the second wire to the MCU is smaller than the distance from the first wire to the MCU.

[0095] Connecting the first inductor to the first wire through first pins at both ends of the first inductor, and connecting the second inductor to the second wire through second pins at both ends of the second inductor;

[0096] The installation point is located at the center of the first inductor and the second inductor, and the distance between the first inductor and the second inductor is a preset distance.

[0097] Therefore, the induced currents generated by the BMS circuit in the first inductor and the second inductor are consistent.

[0098] Reference Figure 6 As shown, obtaining the interference ratio of the BMS circuit to the sampling resistor includes the following steps:

[0099] The BMS uses a preset current for charging and calculates the sample current value at the second inductor based on the resistance distribution of the BMS circuit;

[0100] The actual current value is measured at the second inductor, and the sample current value is subtracted from the actual current value and divided by the actual current value to obtain the interference ratio.

[0101] The interference ratio here is obtained by measuring at the second inductor. Since the current at the second inductor is amplified, the measurement error will be smaller. The interference ratio is used to describe the interference situation in the first inductor. Since the induced magnetic fields generated by the external BMS in the first inductor and the second inductor are consistent, but since the number of coil turns of the first inductor and the second inductor is different, the generated induced current is proportional to the number of coil turns. At the same time, since the amplification of the current by the first inductor and the second inductor is also proportional to the number of coil turns of the first inductor and the second inductor, the interference ratio in the second inductor is consistent with the interference ratio in the first inductor. As long as the interference ratio in the second inductor is calculated, it can be used as the interference ratio in the first inductor.

[0102] Reference Figure 7 As shown, measuring the actual current value at the second inductor includes the following steps:

[0103] Based on historical measurement data, obtain the average error rate of small current measurement;

[0104] measuring at least one test current value at the second inductor, and using a maximum value and a minimum value of the at least one test current value as endpoints to form a current value interval;

[0105] uniformly selecting at least one identification point in the current value interval;

[0106] Calculating the error ratio of at least one test current value relative to the identification point respectively, and taking an average of the at least one error ratio to obtain an actual error rate;

[0107] The value of the identification point corresponding to the actual error rate that has the smallest difference from the average error rate is taken as the actual current value.

[0108] Since there are errors in the measurement, in order to reduce the error, the actual current value is obtained by averaging the error rate. The basis for selection is that the mean of the error between at least one test current value and the actual current value is closest to the average error rate. Therefore, the identification points are successively assumed to be the true value of the current of the second inductor, and the actual error rate of each identification point is calculated accordingly, and then the actual current value can be selected. The subsequent actual current signal is also based on a similar principle. During the test, alternating current is used, so the current value can be calculated, but actual charging and discharging uses alternating current, so it is an actual current signal, not a constant value.

[0109] Reference Figure 8 As shown, performing interference removal processing on the actual current signal to obtain a current filtered signal includes the following steps:

[0110] Acquire an actual current signal at the first inductor, and multiply the actual current signal by the interference ratio to obtain a current interference signal;

[0111] Decomposing the actual current signal using Fourier transform to obtain at least one actual basic signal;

[0112] Decomposing the current interference signal using Fourier transform to obtain at least one basic interference signal;

[0113] Deleting the actual basic signal that is equal to the interfering basic signal;

[0114] The at least one actual basic signal after deletion is combined using inverse Fourier transform to obtain a current filtering signal.

[0115] The Fourier transform is as follows: ,

[0116] Where F(x) is the signal after Fourier transform, i is the unit imaginary number, e is the natural constant, f(t) is the signal before Fourier transform, f(t) is the time domain function, and t is time;

[0117] The inverse Fourier transform is as follows: ,

[0118] Where G(t) is the signal before inverse Fourier transform, i is the unit imaginary number, e is a natural constant, g(x) is the signal after inverse Fourier transform, g(x) is the frequency domain function, and x is the frequency.

[0119] Reference Figure 9 As shown, obtaining the actual current signal at the first inductor includes the following steps:

[0120] measuring at least one test current signal at the first inductor, taking one of the at least one test current signal as a current signal to be verified, and taking the remaining test current signal as a non-verification current signal;

[0121] Calculate the average forward current of the current signal to be verified in one cycle as the value to be verified;

[0122] Calculate the average value of the forward current of the non-verification current signal in one cycle as the non-verification value;

[0123] Calculate the error ratio of at least one non-verified value relative to the value to be verified and take the average to obtain the ratio to be verified;

[0124] After the current signal to be verified traverses the test current signal, the current signal to be verified corresponding to the ratio to be verified with the smallest difference from the average error rate is taken as the actual current signal.

[0125] When integrating over the entire cycle, the integral value must be 0. Therefore, in order to obtain the current values ​​of the current signal to be verified and the non-verification current signal, only the waveform in half a cycle is integrated. Here, the half cycle of the positive current is selected.

[0126] The amplification process of the current filter signal includes the following steps:

[0127] After the current filter signal flows through the sampling resistor, it is amplified.

[0128] Furthermore, the present solution also proposes a storage medium on which a computer-readable program is stored. When the computer-readable program is called, the above-mentioned battery protection method based on BMS dormant small current identification and detection is executed.

[0129] It is understandable that the storage medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; an optical medium, such as a DVD; or a semiconductor medium, such as a solid state disk (SSD).

[0130] In summary, the advantages of the present invention are: by forming the installation point of the sampling resistor, performing the structural setting of the sampling resistor, obtaining the interference ratio of the sampling resistor and obtaining the current filter signal, the interference induced current signal generated by the BMS can be determined at the sampling resistor, and then the induced current signal can be removed according to the actual situation, and the current signal after the interference is removed can be amplified. Due to the structural setting of the sampling resistor, the current signal after the interference is removed can be amplified to the extent of triggering the interrupt condition of the I / O port of the MCU, thereby ensuring that a small current will inevitably wake up the MCU, thereby ensuring the protection of the battery.

[0131] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions merely illustrate the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A battery protection method based on BMS dormant low current identification and detection, characterized in that: include: Form the installation points of the sampling resistor in the BMS circuit and set the structure of the sampling resistor; Pre-set the BMS. The interrupt condition of the MCU's I / O port is that the current passing through the I / O port is greater than the preset value. Connect the sampling resistor to the BMS circuit according to the setting of the installation point. Obtain the interference ratio of the BMS circuit to the sampling resistor; When the BMS charging and discharging current is greater than the wake-up current detection threshold, the BMS front end is awakened, the BMS front end wakes up the MCU, and the MCU performs battery protection; When the BMS charge and discharge current does not exceed the wake-up current detection threshold, the sampling resistor amplifies the BMS charge and discharge current, reaching the interrupt condition of the MCU's I / O port. The I / O port is connected to the MCU, and the MCU wakes up through an external interrupt, and the MCU performs battery protection. When the sampling resistor amplifies the BMS charging and discharging current, it uses the interference ratio to remove the interference from the actual current signal to obtain the current filter signal, which is then amplified. Obtaining the interference ratio of the BMS circuit to the sampling resistor includes the following steps: The BMS uses a preset current for charging and calculates the sample current value at the second inductor based on the resistance distribution of the BMS circuit; The actual current value is measured at the second inductor, the sample current value is subtracted from the actual current value and then divided by the actual current value to obtain the interference ratio; The interference removal process of the actual current signal to obtain the current filtered signal comprises the following steps: Acquire an actual current signal at the first inductor, and multiply the actual current signal by the interference ratio to obtain a current interference signal; Decomposing the actual current signal using Fourier transform to obtain at least one actual basic signal; Decomposing the current interference signal using Fourier transform to obtain at least one basic interference signal; Deleting the actual basic signal that is equal to the interfering basic signal; The at least one actual basic signal after deletion is combined using inverse Fourier transform to obtain a current filtering signal.

2. A battery protection method based on BMS dormant low current identification and detection according to claim 1, characterized in that: The steps of forming the installation point of the sampling resistor in the BMS circuit include the following steps: Obtain at least one wire directly connected to the MCU in the BMS circuit, obtain the current value of the wire when the BMS is charging and discharging, select the wire with the largest current value as the target wire, and evenly select at least one sampling point on the target wire; The BMS uses a preset current for charging, which is direct current. A first closed circuit and a second closed circuit are set at a sampling point. The first closed circuit and the second closed circuit are not connected to the BMS circuit. The first closed circuit and the second closed circuit are of the same size. The sampling point is located at the center of the first closed circuit and the second closed circuit. The distance between the first closed circuit and the second closed circuit is a preset distance. Acquire a first induced current signal in the first closed circuit, and acquire a second induced current signal in the second closed circuit; When the first induced current signal and the second induced current signal are equal, the sampling point where the first induced current signal and the second induced current signal are obtained is used as the installation point of the sampling resistor; When there is no sampling point that makes the first induced current signal equal to the second induced current signal, a sampling point is added at the midpoint of the adjacent sampling points. After the addition, if there is a sampling point that makes the first induced current signal equal to the second induced current signal, the addition is stopped; if not, the addition of sampling points continues.

3. The battery protection method based on BMS dormant low current identification and detection according to claim 2 is characterized in that: The structural setting of the sampling resistor comprises the following steps: Obtain the maximum value of the induced current generated by the BMS circuit on the sampling resistor. Based on historical data, obtain the minimum current value during the charging and discharging of the BMS circuit as the characteristic current. The sampling resistor is composed of a first inductor and a second inductor, the first inductor and the second inductor are not connected, and the distance between the first inductor and the second inductor is a preset distance; Both ends of the first inductor are provided with first pins, and both ends of the second inductor are provided with second pins; Setting the number of turns of the coil of the first inductor to a preset number of turns, where the preset number of turns is any value less than 10; Obtain the absolute value of the difference between the characteristic current and the maximum value of the induced current as the target value; The preset number of turns is divided by the target value and multiplied by the preset value to obtain the preliminary number of turns, the preliminary number of turns is rounded to obtain the target number of turns, and the number of turns of the coil of the second inductor is set to the target number of turns.

4. The battery protection method based on BMS dormant low current identification and detection according to claim 3 is characterized in that: The pre-setting of the BMS comprises the following steps: The front-end battery management chip in the BMS is used as the BMS front end, and the chip responsible for communication and event processing in the BMS is used as the MCU; Obtain the wake-up current detection threshold of the BMS front end. The BMS charging and discharging current flows through the sampling resistor. The sampling resistor is connected in series with the I / O port, and the I / O port is connected to the MCU as a pin.

5. The battery protection method based on BMS dormant low current identification and detection according to claim 4 is characterized in that: Connecting the sampling resistor to the BMS circuit according to the installation point setting includes the following steps: Divide the target wire into two parts: the first wire and the second wire. The dividing point is the installation point of the sampling resistor. The distance from the second wire to the MCU is smaller than the distance from the first wire to the MCU. Connecting the first inductor to the first wire through first pins at both ends of the first inductor, and connecting the second inductor to the second wire through second pins at both ends of the second inductor; The installation point is located at the center of the first inductor and the second inductor, and the distance between the first inductor and the second inductor is a preset distance.

6. The battery protection method based on BMS dormant low current identification and detection according to claim 5 is characterized in that: The step of measuring the actual current value at the second inductor comprises the following steps: Based on historical measurement data, obtain the average error rate of small current measurement; measuring at least one test current value at the second inductor, and using a maximum value and a minimum value of the at least one test current value as endpoints to form a current value interval; uniformly selecting at least one identification point in the current value interval; Calculating the error ratio of at least one test current value relative to the identification point respectively, and taking an average of the at least one error ratio to obtain an actual error rate; The value of the identification point corresponding to the actual error rate that has the smallest difference from the average error rate is taken as the actual current value.

7. A battery protection method based on BMS dormant low current identification and detection according to claim 6, characterized in that: The step of obtaining the actual current signal at the first inductor comprises the following steps: measuring at least one test current signal at the first inductor, taking one of the at least one test current signal as a current signal to be verified, and taking the remaining test current signal as a non-verification current signal; Calculate the average forward current of the current signal to be verified in one cycle as the value to be verified; Calculate the average value of the forward current of the non-verification current signal in one cycle as the non-verification value; Calculate the error ratio of at least one non-verified value relative to the value to be verified and take the average to obtain the ratio to be verified; After the current signal to be verified traverses the test current signal, the current signal to be verified corresponding to the ratio to be verified with the smallest difference from the average error rate is taken as the actual current signal.

8. The battery protection method based on BMS dormant low current identification and detection according to claim 7 is characterized in that: The amplifying process of the current filter signal comprises the following steps: After the current filter signal flows through the sampling resistor, it is amplified.

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