A state of charge estimation method based on virtual incremental injection

Abstract

The application relates to the technical field of battery energy storage, and discloses a state-of-charge estimation method based on virtual incremental injection, which comprises the following steps: obtaining a battery current at a current moment and a battery terminal voltage at a previous static moment, and calculating a relative residual state-of-charge at the current moment; setting the maximum value and the minimum value of the battery terminal voltage as control targets of a first virtual incremental injection module and a second virtual incremental injection module, and predicting the maximum value and the minimum value of the relative residual state-of-charge at the current moment by using a proportional-integral controller; calculating a total capacity actually available to the battery and a residual capacity of the battery at the current moment; and calculating an actual residual state-of-charge of the battery at the current moment. The application can obtain the virtual increment in real time without injecting a real current increment or a voltage increment, without performing multiple iterative calculations, and without being limited by working conditions such as battery charging or discharging.

Description

Technical Field

[0001] This invention relates to the field of battery energy storage technology, and specifically to a method for estimating the state of charge based on virtual incremental injection. Background Technology

[0002] Typically, cost-sensitive battery management systems combine the ampere-hour integration method and the open-circuit voltage method to estimate the battery's remaining state of charge (SOC). Specifically, the open-circuit voltage method is used to obtain the SOC when the battery is at rest, while the ampere-hour integration method is used to obtain the change in SOC during charging or discharging. This approach uses the total battery capacity corresponding to the open-circuit voltage curve as the full charge capacity. However, actual users often use the amount of charge stored between the maximum and minimum battery terminal voltages as the full charge capacity. This difference in the definition of full charge capacity leads to a discrepancy between the estimated SOC and the user's actual expected SOC. To address this issue, some solutions artificially inject current pulses during normal battery use to discharge or charge the battery, thereby achieving continuous estimation of the actual SOC. However, these injected current pulses directly impact the user experience and increase system losses. Another approach uses an iterative search method to incrementally search the battery's state of charge to obtain the user-defined full charge capacity. However, the fewer the iterations, the lower the estimation accuracy, while increasing the number of iterations will prolong the system's computation time and increase system power consumption. Summary of the Invention

[0003] To address the aforementioned shortcomings of existing technologies, this invention provides a method for estimating the state of charge (SOC) based on virtual incremental injection. This invention first uses the maximum and minimum values ​​of the battery terminal voltage, set by the user, as the control targets for the virtual incremental injection module. Then, a proportional-integral (PI) controller is used to acquire the virtual increment to be injected in real time. Next, the maximum and minimum values ​​of the battery's relative remaining SOC are predicted by combining these values ​​with the battery's current relative SOC. Finally, based on the maximum and minimum values ​​of the battery's relative SOC and the battery's current relative SOC, the actual usable total capacity of the battery and the usable remaining SOC at the current moment are calculated. This invention does not require injecting actual current or voltage increments, nor does it require multiple iterative calculations to acquire the virtual increment in real time; and it is not limited by battery charging or discharging conditions.

[0004] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0005] A method for estimating the state of charge based on virtual incremental injection includes the following steps:

[0006] Obtain the current battery current and the battery terminal voltage at the previous resting time, and calculate the relative residual state of charge at the current time by combining the ampere-hour integration method and the open-circuit voltage method.

[0007] The maximum and minimum values ​​of the battery terminal voltage are set as the control targets of the first virtual incremental injection module and the second virtual incremental injection module. The maximum and minimum values ​​of the relative residual state of charge at the current moment are predicted by a proportional-integral controller.

[0008] The actual usable total capacity of the battery and the remaining capacity of the battery at the current moment are calculated based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment.

[0009] The actual remaining state of charge of the battery at the current moment is calculated based on the total usable capacity of the battery and the remaining capacity of the battery at the current moment.

[0010] Furthermore, the battery current at the current moment and the battery terminal voltage at the previous resting moment are obtained, and the relative residual state of charge at the current moment is calculated by combining the ampere-hour integration method and the open-circuit voltage method, including:

[0011] Based on the battery terminal voltage at the previous resting time, the relative residual state of charge at the previous resting time is determined by the battery open-circuit voltage curve.

[0012] Based on the current battery current, the change in the battery's state of charge at the current moment is calculated using the ampere-hour integration method and the open-circuit voltage method.

[0013] The relative remaining state of charge at the current moment is calculated based on the relative remaining state of charge at the previous resting moment and the change in the state of charge of the battery at the current moment.

[0014] Furthermore, the relative remaining state of charge at the current moment is calculated based on the relative remaining state of charge at the previous resting moment and the change in the battery's state of charge at the current moment, specifically as follows:

[0015] ,

[0016] Wherein, SOCcur is the relative remaining state of charge at the current moment, SOCrest is the relative remaining state of charge at the previous resting moment, and SOCvar is the change in the battery's state of charge at the current moment.

[0017] Furthermore, the maximum value of the battery terminal voltage is set as the control target of the first virtual incremental injection module, and a proportional-integral controller is used to predict the maximum value of the relative remaining state of charge at the current moment, including:

[0018] The maximum value of the battery terminal voltage is set as the control target of the first virtual incremental injection module, and a proportional-integral controller is used to obtain the virtual increment that the first virtual incremental injection module needs to inject in real time.

[0019] The maximum value of the relative residual charge state at the current moment is predicted based on the virtual increment to be injected by the first virtual increment injection module and the relative residual charge state at the current moment.

[0020] Furthermore, a proportional-integral controller is used to obtain the virtual increment to be injected by the first virtual increment injection module in real time, specifically as follows:

[0021] ,

[0022] ,

[0023] Wherein, SOCinc0 is the virtual increment to be injected by the first virtual incremental injection module, kp0 is the proportional gain coefficient of the first virtual incremental injection module, e0 is the control error of the first virtual incremental injection module, ki0 is the integral gain coefficient of the first virtual incremental injection module, Vmax is the maximum value of the set battery terminal voltage, and Vpre0 is the battery terminal voltage estimated by the first virtual incremental injection module.

[0024] Furthermore, based on the virtual increment to be injected by the first virtual increment injection module and the current relative residual state of charge, the maximum value of the current relative residual state of charge is predicted, specifically as follows:

[0025] ,

[0026] Wherein, SOCpre0 is the maximum value of the relative remaining state of charge at the current time, SOCcur is the relative remaining state of charge at the current time, and SOCinc0 is the virtual increment to be injected by the first virtual increment injection module.

[0027] Furthermore, the minimum value of the battery terminal voltage is set as the control target of the second virtual incremental injection module. A proportional-integral controller is used to predict the minimum value relative to the remaining state of charge at the current moment, including:

[0028] The minimum value of the battery terminal voltage is set as the control target of the second virtual incremental injection module, and the virtual increment to be injected by the second virtual incremental injection module is obtained in real time using a proportional-integral controller.

[0029] The minimum value of the relative residual charge state at the current moment is predicted based on the virtual increment to be injected by the second virtual increment injection module and the relative residual charge state at the current moment.

[0030] Furthermore, based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment, the actual usable total capacity of the battery and the remaining capacity of the battery at the current moment are calculated, including:

[0031] The remaining capacity of the battery at the current moment is calculated based on the minimum value of the relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment.

[0032] The actual usable total capacity of the battery is calculated based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment.

[0033] Furthermore, the remaining capacity of the battery at the current moment is calculated based on the minimum relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment, specifically as follows:

[0034] ,

[0035] Where Qrem is the remaining capacity of the battery at the current moment, SOCcur is the relative remaining state of charge at the current moment, SOCpre1 is the minimum value of the relative remaining state of charge at the current moment, and Qocv is the total battery capacity of the battery open-circuit voltage curve.

[0036] Furthermore, the actual usable total capacity of the battery is calculated based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment, specifically as follows:

[0037] ,

[0038] Where Qtotal is the total usable capacity of the battery, SOCpre0 is the maximum value of the relative remaining state of charge at the current moment, SOCpre1 is the minimum value of the relative remaining state of charge at the current moment, and Qocv is the total battery capacity of the battery open-circuit voltage curve.

[0039] The present invention has the following beneficial effects:

[0040] This invention can obtain virtual increments in real time without injecting real current or voltage increments or performing multiple iterative calculations; and it is not limited by operating conditions such as battery charging or discharging. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a charge state estimation method based on virtual incremental injection;

[0042] Figure 2 This is a block diagram illustrating the principle of the charge state estimation method based on virtual incremental injection.

[0043] Figure 3 Internal principle block diagram of the first virtual incremental injection module;

[0044] Figure 4 Internal principle block diagram of the second virtual incremental injection module;

[0045] Figure 5 Estimating the state of charge waveform for the entire process of unequal charging intervals of the battery;

[0046] Figure 6 The waveform is used to estimate the state of charge of the battery during the entire process of unequal interval discharge. Detailed Implementation

[0047] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0048] like Figure 1 As shown, an embodiment of the present invention provides a method for estimating the state of charge based on virtual incremental injection, comprising the following steps S1 to S4:

[0049] S1. Obtain the current battery current and the battery terminal voltage at the previous resting time, and calculate the relative residual state of charge at the current time by combining the ampere-hour integration method and the open-circuit voltage method.

[0050] In an optional embodiment of the present invention, step S1 obtains the battery current at the current moment and the battery terminal voltage at the previous resting moment, and calculates the relative residual state of charge at the current moment by combining the ampere-hour integration method and the open-circuit voltage method, including:

[0051] Based on the battery terminal voltage at the previous resting time, the relative residual state of charge at the previous resting time is determined by the battery open-circuit voltage curve.

[0052] Based on the current battery current, the change in the battery's state of charge at the current moment is calculated using the ampere-hour integration method and the open-circuit voltage method.

[0053] The relative remaining state of charge at the current moment is calculated based on the relative remaining state of charge at the previous resting moment and the change in the state of charge of the battery at the current moment.

[0054] In this embodiment, the open circuit voltage curve represents the relationship between the battery open circuit voltage (OCV) and the battery remaining state of charge (SOC). The open circuit voltage curve will be referred to as the OCV curve below.

[0055] The open-circuit voltage-ampere-hour integration method uses the open-circuit voltage method to obtain the battery's state of charge at rest. Specifically, it obtains the battery's terminal voltage Vrest at fully rested state as the open-circuit voltage, and then obtains the relative remaining state of charge SOCrest at rest by consulting the OCV curve. The calculation formula is as follows:

[0056] ,

[0057] The open-circuit voltage-ampere-hour integration method uses the ampere-hour integration method to obtain the change in the state of charge of the battery during charging or discharging. The calculation formula is as follows:

[0058] ,

[0059] Where SOCvar is the change in state of charge. For charge / discharge time, Where is the battery current, and Qocv is the total battery capacity corresponding to the OCV curve.

[0060] The relative remaining state of charge at the current moment is calculated based on the relative remaining state of charge at the previous resting moment and the change in the battery's state of charge at the current moment, specifically as follows:

[0061] ,

[0062] Wherein, SOCcur is the relative remaining state of charge at the current moment, SOCrest is the relative remaining state of charge at the previous resting moment, and SOCvar is the change in the battery's state of charge at the current moment.

[0063] S2. Set the maximum and minimum values ​​of the battery terminal voltage as the control targets of the first virtual incremental injection module and the second virtual incremental injection module, and use a proportional-integral controller to predict the maximum and minimum values ​​of the relative residual charge state at the current moment.

[0064] In an optional embodiment of the present invention, step S2 sets the maximum value of the battery terminal voltage to the control target of the first virtual incremental injection module, and uses a proportional-integral controller to predict the maximum value relative to the remaining state of charge at the current moment, including:

[0065] The maximum value of the battery terminal voltage is set as the control target of the first virtual incremental injection module, and a proportional-integral controller is used to obtain the virtual increment that the first virtual incremental injection module needs to inject in real time.

[0066] The maximum value of the relative residual charge state at the current moment is predicted based on the virtual increment to be injected by the first virtual increment injection module and the relative residual charge state at the current moment.

[0067] In this embodiment, since the polarization voltage in the battery equivalent circuit model cannot be measured, and the polarization impedance introduces many battery parameters to be measured, the cost-sensitive battery management system typically uses the equivalent internal resistance model as the battery's equivalent circuit model. Therefore, taking this model as an example, its calculation formula is as follows:

[0068] ,

[0069] Where V is the battery terminal voltage, R0 is the battery equivalent internal resistance, and VOC (SOC) represents the battery open-circuit voltage corresponding to the current state of charge SOC in the OCV curve.

[0070] The open-circuit voltage-ampere-hour integration method uses the total battery capacity corresponding to the OCV curve as the full-charge capacity. However, actual users often use the amount of charge stored between the maximum and minimum values ​​of the battery terminal voltage as the full-charge capacity. This difference in the definition of full-charge capacity leads to a discrepancy between the estimated remaining state of charge (SOC) of this method and the user's actual expected SOC. Therefore, it is necessary to incorporate consideration of the applicable range of the battery terminal voltage into the open-circuit voltage-ampere-hour integration method.

[0071] like Figure 3 The diagram shown is an internal block diagram of the first virtual incremental injection module. This module uses the maximum battery terminal voltage set by the user as the control target and employs a proportional-integral controller to obtain the virtual increment to be injected in real time. Specifically:

[0072] ,

[0073] ,

[0074] Wherein, SOCinc0 is the virtual increment to be injected by the first virtual incremental injection module, kp0 is the proportional gain coefficient of the first virtual incremental injection module, e0 is the control error of the first virtual incremental injection module, ki0 is the integral gain coefficient of the first virtual incremental injection module, Vmax is the maximum value of the set battery terminal voltage, and Vpre0 is the battery terminal voltage estimated by the first virtual incremental injection module.

[0075] Then, by combining the battery's current relative remaining state of charge, the maximum value of the battery's relative remaining state of charge is predicted, specifically:

[0076] ,

[0077] Wherein, SOCpre0 is the maximum value of the relative remaining state of charge at the current time, SOCcur is the relative remaining state of charge at the current time, and SOCinc0 is the virtual increment to be injected by the first virtual increment injection module.

[0078] The battery open-circuit voltage Vocv0 corresponding to the state of charge SOCpre0 in the OCV curve is:

[0079] ,

[0080] The proportional-integral controller continuously and automatically adjusts the injected virtual increment SOCinc0 to ensure that the estimated battery terminal voltage Vpre0 is:

[0081] ,

[0082] Where Ichg represents the magnitude of the charging current.

[0083] In the first virtual incremental injection module, the proportional-integral controller continuously and automatically adjusts the injected virtual increment SOCinc0 so that the estimated battery terminal voltage Vpre0 tends to converge to Vmax. At the same time, the maximum value of the battery relative residual state of charge SOCpre0 predicted by the first virtual incremental injection module will also tend to converge to the maximum value of the actual battery relative residual state of charge corresponding to the battery terminal voltage Vmax.

[0084] Step S2 sets the minimum value of the battery terminal voltage as the control target of the second virtual incremental injection module, and uses a proportional-integral controller to predict the minimum value of the relative remaining state of charge at the current moment, including:

[0085] The minimum value of the battery terminal voltage is set as the control target of the second virtual incremental injection module, and the virtual increment to be injected by the second virtual incremental injection module is obtained in real time using a proportional-integral controller.

[0086] The minimum value of the relative residual charge state at the current moment is predicted based on the virtual increment to be injected by the second virtual increment injection module and the relative residual charge state at the current moment.

[0087] like Figure 4 The diagram shown is an internal block diagram of the second virtual incremental injection module. This module uses the minimum battery terminal voltage set by the user as the control target and employs a proportional-integral controller to obtain the virtual increment to be injected in real time. Specifically:

[0088] ,

[0089] ,

[0090] Wherein, SOCinc1 is the virtual increment to be injected by the second virtual incremental injection module, kp1 is the proportional gain coefficient of the second virtual incremental injection module, e1 is the control error of the second virtual incremental injection module, ki1 is the integral gain coefficient of the second virtual incremental injection module, Vmin is the minimum value of the set battery terminal voltage, and Vpre1 ​​is the battery terminal voltage estimated by the second virtual incremental injection module.

[0091] Then, by combining the battery's current relative remaining state of charge, the minimum value of the battery's relative remaining state of charge is predicted, specifically:

[0092] ,

[0093] Wherein, SOCpre1 is the minimum value of the relative remaining state of charge at the current moment, SOCcur is the relative remaining state of charge at the current moment, and SOCinc1 is the virtual increment to be injected by the second virtual increment injection module.

[0094] The battery open-circuit voltage Vocv1 corresponding to the state of charge SOCpre1 in the OCV curve is:

[0095] ,

[0096] The proportional-integral controller continuously and automatically adjusts the injected virtual increment SOCinc1 to ensure that the estimated battery terminal voltage Vpre1 ​​is:

[0097] ,

[0098] Where Idsg represents the magnitude of the discharge current.

[0099] In the second virtual incremental injection module, the proportional-integral controller continuously and automatically adjusts the injected virtual increment SOCinc1 so that the estimated battery terminal voltage Vpre1 ​​tends to converge to Vmin. At the same time, the maximum value of the battery relative residual state of charge SOCpre1 predicted by the second virtual incremental injection module will also tend to converge to the minimum value of the actual battery relative residual state of charge corresponding to the battery terminal voltage Vmin.

[0100] S3. Calculate the actual total usable capacity of the battery and the remaining capacity of the battery at the current moment based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment.

[0101] In an optional embodiment of the present invention, step S3 calculates the actual usable total capacity of the battery and the remaining capacity of the battery at the current moment based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment, including:

[0102] The remaining capacity of the battery at the current moment is calculated based on the minimum value of the relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment.

[0103] The actual usable total capacity of the battery is calculated based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment.

[0104] In this embodiment, as Figure 2 The diagram shows the principle block diagram of the state of charge estimation method based on virtual incremental injection. Based on the outputs of the two virtual incremental injection modules and the current relative remaining state of charge (SOCcur), the remaining capacity of the battery at the current moment and the actual usable total capacity of the battery stored between the battery terminal voltages Vmax and Vmin can be calculated.

[0105] This embodiment calculates the remaining battery capacity at the current moment based on the minimum relative remaining state of charge and the current relative remaining state of charge. Specifically:

[0106] ,

[0107] Where Qrem is the remaining capacity of the battery at the current moment, SOCcur is the relative remaining state of charge at the current moment, SOCpre1 is the minimum value of the relative remaining state of charge at the current moment, and Qocv is the total battery capacity of the battery open-circuit voltage curve.

[0108] This embodiment calculates the actual usable total capacity of the battery based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment, specifically as follows:

[0109] ,

[0110] Where Qtotal is the total usable capacity of the battery, SOCpre0 is the maximum value of the relative remaining state of charge at the current moment, SOCpre1 is the minimum value of the relative remaining state of charge at the current moment, and Qocv is the total battery capacity of the battery open-circuit voltage curve.

[0111] S4. Calculate the actual remaining state of charge of the battery at the current moment based on the total usable capacity of the battery and the remaining capacity of the battery at the current moment.

[0112] In an optional embodiment of the present invention, step S4 calculates the actual remaining state of charge (SOCact) of the battery at the current moment based on the battery's remaining capacity Qrem and the battery's actual total usable capacity Qtotal. The calculation formula is as follows:

[0113] ,

[0114] The ratio of the battery's actual usable total capacity to the total capacity corresponding to the OCV curve is:

[0115] ,

[0116] When the ratio is greater than 1, it means that the actual usable total battery capacity corresponding to the user-set maximum and minimum battery terminal voltage values ​​exceeds the total capacity corresponding to the OCV curve. If it exceeds the total capacity corresponding to the OCV curve, the system will be unable to obtain the correct relative remaining state of charge of the battery based on the OCV curve under certain operating conditions (such as overcharge or over-discharge conditions), resulting in errors in the open-circuit voltage-ampere-hour integration method. In this case, the user should be reminded to modify the maximum and minimum values ​​of the battery terminal voltage they set. If the actual maximum and minimum terminal voltage values ​​cannot be changed, the battery's OCV curve should be updated to cover the maximum range of battery terminal voltages actually used by the user.

[0117] Taking the intermittent charge and discharge condition of an 18650 lithium battery as an example, Figure 5 Estimating the state of charge waveform for the entire charging process of a battery with unequal charging intervals. Figure 6 The waveform for estimating the state of charge (SOC) throughout the entire unequal discharge process of the battery is presented. Figure 5 and Figure 6 In the diagram, the waveforms from top to bottom represent the battery terminal voltage, battery current, and estimated battery state of charge, respectively. Figure 5 and Figure 6 It can be seen that this state of charge estimation method has good dynamic and steady-state performance during the intermittent charging or discharging of the battery.

[0118] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0119] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0120] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0121] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

[0122] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A method for estimating the state of charge based on virtual incremental injection, characterized in that, Includes the following steps: Obtain the current battery current and the battery terminal voltage at the previous resting time, and calculate the relative residual state of charge at the current time by combining the ampere-hour integration method and the open-circuit voltage method. The maximum and minimum values ​​of the battery terminal voltage are set as the control targets of the first and second virtual incremental injection modules. A proportional-integral controller is used to predict the maximum and minimum values ​​relative to the current residual state of charge, including: The maximum value of the battery terminal voltage is set as the control target of the first virtual incremental injection module. A proportional-integral controller is used to obtain the virtual increment that the first virtual incremental injection module needs to inject in real time. Specifically: ， ， Wherein, SOCinc0 is the virtual increment to be injected by the first virtual incremental injection module, kp0 is the proportional gain coefficient of the first virtual incremental injection module, e0 is the control error of the first virtual incremental injection module, ki0 is the integral gain coefficient of the first virtual incremental injection module, Vmax is the maximum value of the set battery terminal voltage, and Vpre0 is the battery terminal voltage estimated by the first virtual incremental injection module. The minimum battery terminal voltage is set as the control target of the second virtual incremental injection module. A proportional-integral controller is used to predict the minimum value relative to the remaining state of charge at the current moment, including: The minimum value of the battery terminal voltage is set as the control target of the second virtual incremental injection module, and the virtual increment to be injected by the second virtual incremental injection module is obtained in real time using a proportional-integral controller. The minimum value of the relative residual charge state at the current moment is predicted based on the virtual increment to be injected by the second virtual increment injection module and the relative residual charge state at the current moment. Based on the virtual increment to be injected by the first virtual increment injection module and the current relative residual charge state, the maximum value of the current relative residual charge state is predicted, specifically as follows: ， Where SOCpre0 is the maximum value of the relative remaining charge state at the current time, SOCcur is the relative remaining charge state at the current time, and SOCinc0 is the virtual increment to be injected by the first virtual increment injection module. The actual usable total capacity of the battery and the remaining capacity of the battery at the current moment are calculated based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment. The actual remaining state of charge of the battery at the current moment is calculated based on the total usable capacity of the battery and the remaining capacity of the battery at the current moment.

2. The method for estimating the state of charge based on virtual incremental injection according to claim 1, characterized in that, Obtain the current battery current and the battery terminal voltage at the previous resting time, and calculate the relative remaining state of charge at the current time using the ampere-hour integration method and the open-circuit voltage method, including: Based on the battery terminal voltage at the previous resting time, the relative residual state of charge at the previous resting time is determined by the battery open-circuit voltage curve. Based on the current battery current, the change in the battery's state of charge at the current moment is calculated using the ampere-hour integration method and the open-circuit voltage method. The relative remaining state of charge at the current moment is calculated based on the relative remaining state of charge at the previous resting moment and the change in the state of charge of the battery at the current moment.

3. The method for estimating the state of charge based on virtual incremental injection according to claim 2, characterized in that, The relative remaining state of charge at the current moment is calculated based on the relative remaining state of charge at the previous resting moment and the change in the battery's state of charge at the current moment, specifically as follows: ， Wherein, SOCcur is the relative remaining state of charge at the current moment, SOCrest is the relative remaining state of charge at the previous resting moment, and SOCvar is the change in the battery's state of charge at the current moment.

4. The method for estimating the state of charge based on virtual incremental injection according to claim 1, characterized in that, The actual usable total capacity of the battery and the remaining capacity of the battery at the current moment are calculated based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment, including: The remaining capacity of the battery at the current moment is calculated based on the minimum value of the relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment. The actual usable total capacity of the battery is calculated based on the maximum and minimum values ​​of the relative remaining state of charge at the current moment.

5. The method for estimating the state of charge based on virtual incremental injection according to claim 4, characterized in that, The remaining capacity of the battery at the current moment is calculated based on the minimum relative remaining state of charge at the current moment and the relative remaining state of charge at the current moment, specifically as follows: ， Where Qrem is the remaining capacity of the battery at the current moment, SOCcur is the relative remaining state of charge at the current moment, SOCpre1 is the minimum value of the relative remaining state of charge at the current moment, and Qocv is the total battery capacity of the battery open-circuit voltage curve.

6. The method for estimating the state of charge based on virtual incremental injection according to claim 4, characterized in that, The actual usable total capacity of the battery is calculated based on the maximum and minimum values ​​of the current relative remaining state of charge, specifically: ， Where Qtotal is the total usable capacity of the battery, SOCpre0 is the maximum value of the relative remaining state of charge at the current moment, SOCpre1 is the minimum value of the relative remaining state of charge at the current moment, and Qocv is the total battery capacity of the battery open-circuit voltage curve.

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