Charge state estimation method based on virtual increment injection

Abstract

The invention relates to the technical field of battery energy storage, and discloses a virtual incremental injection-based charge state estimation method, which comprises the following steps of: acquiring a battery current at a current moment and a battery end voltage at a previous standing moment, and calculating a relative residual charge state at the current moment; the maximum value and the minimum value of the battery end voltage are set as control targets of a first virtual increment injection module and a second virtual increment injection module, and the maximum value and the minimum value of the relative residual charge state at the current moment are predicted by adopting a proportional-integral controller; calculating the actual available total capacity of the battery and the residual capacity of the battery at the current moment; and calculating the actual residual state of charge of the battery at the current moment. According to the method, the virtual increment can be obtained in real time without injecting real current increment or voltage increment or performing iterative computation for multiple times; and the method is not limited by working conditions such as battery charging or discharging.

Description

Technical Field

[0001] The present invention relates to the technical field of battery energy storage, and in particular to a state of charge estimation method based on virtual incremental injection. Background Art

[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 battery's SOC when the battery is at rest, and the ampere-hour integration method is used to obtain the change in SOC during charging or discharging. Such solutions use the total battery capacity corresponding to the battery's open-circuit voltage curve as the full-charge capacity, while actual users often use the charge stored between the maximum and minimum values ​​of the battery's terminal voltage as the full-charge capacity. This difference in the definition of full-charge capacity can lead to differences between the estimated SOC of such solutions 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 continuously estimating the actual battery's remaining SOC. However, the current pulses injected by such solutions directly affect the user experience and increase system losses. There are also solutions that use search iteration methods to perform incremental searches on the battery's state of charge to obtain the user-defined full charge capacity. However, the fewer the number of iterations of such solutions, the lower the estimation accuracy. Increasing the number of iterations will extend the system's calculation time and increase system power consumption. Summary of the Invention

[0003] In response to the above-mentioned deficiencies in the prior art, the present invention provides a state of charge estimation method based on virtual incremental injection. The present invention first uses the maximum and minimum values ​​of the battery terminal voltage set by the user as the control targets of the virtual incremental injection module, and then uses a proportional integral controller to obtain the virtual increment to be injected in real time, and then combines the relative residual state of charge of the battery at the current moment to predict the maximum and minimum values ​​of the relative residual state of charge of the battery. Finally, based on the maximum and minimum values ​​of the relative residual state of charge of the battery and the relative residual state of charge of the battery at the current moment, the actual total capacity of the battery and the available residual state of charge of the battery at the current moment are calculated. The present invention can obtain virtual increments in real time without injecting real current increments or voltage increments, and without performing multiple iterative calculations; and is not restricted by working conditions such as battery charging or discharging.

[0004] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is: A method for estimating state of charge based on virtual incremental injection comprises the following steps: Obtain the current battery current and the battery terminal voltage at the last resting moment, and calculate the current relative remaining state of charge by combining the ampere-hour integration method and the open-circuit voltage method; Setting the maximum and minimum values ​​of the battery terminal voltage as control targets of the first virtual incremental injection module and the second virtual incremental injection module, and using a proportional-integral controller to predict the maximum and minimum values ​​of the relative remaining state of charge at the current moment; Calculate the actual 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; The actual remaining state of charge of the battery at the current moment is calculated based on the actual total capacity of the battery and the remaining capacity of the battery at the current moment.

[0005] Furthermore, the current battery current and the battery terminal voltage at the last resting moment are obtained, and the current relative remaining state of charge is calculated by combining the ampere-hour integration method and the open circuit voltage method, including: According to the battery terminal voltage at the last static moment, the relative residual state of charge at the last static moment is determined by the battery open circuit voltage curve; According to the current battery current, the change in the battery state of charge at the current moment is calculated by combining 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.

[0006] 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: , Among them, 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.

[0007] Furthermore, the maximum value of the battery terminal voltage is set as the control target of the first virtual incremental injection module, and the proportional-integral controller is used to predict the maximum value of the relative residual state of charge at the current moment, including: Setting the maximum value of the battery terminal voltage as the control target of the first virtual increment injection module, and using a proportional-integral controller to obtain the virtual increment to be injected by the first virtual increment injection module in real time; The maximum value of the relative residual state of charge at the current moment is predicted according to the virtual increment to be injected by the first virtual increment injection module and the relative residual state of charge at the current moment.

[0008] 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: , , Among them, SOCinc0 is the virtual increment to be injected by the first virtual increment injection module, kp0 is the proportional gain coefficient of the first virtual increment injection module, e0 is the control error of the first virtual increment injection module, ki0 is the integral gain coefficient of the first virtual increment injection module, Vmax is the set maximum value of the battery terminal voltage, and Vpre0 is the battery terminal voltage estimated by the first virtual increment injection module.

[0009] Furthermore, the maximum value of the relative residual state of charge 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 state of charge at the current moment, specifically: , Wherein, SOCpre0 is the maximum 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 SOCinc0 is the virtual increment to be injected by the first virtual increment injection module.

[0010] Furthermore, the minimum value of the battery terminal voltage is set as the control target of the second virtual incremental injection module, and the proportional integral controller is used to predict the minimum value of the relative residual state of charge at the current moment, including: Setting the minimum value of the battery terminal voltage as the control target of the second virtual increment injection module, and using a proportional-integral controller to obtain the virtual increment to be injected by the second virtual increment injection module in real time; The minimum value of the relative residual state of charge at the current moment is predicted according to the virtual increment to be injected by the second virtual increment injection module and the relative residual state of charge at the current moment.

[0011] Furthermore, the actual available 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, including: Calculating the remaining capacity of the battery at the current moment according to 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 available 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.

[0012] Furthermore, 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, specifically: , Among them, 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 capacity of the battery in the battery open circuit voltage curve.

[0013] Furthermore, the actual total available capacity of the battery is calculated based on the maximum and minimum values ​​of the current relative remaining state of charge, specifically: , Among them, Qtotal is the total capacity actually available for 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 capacity of the battery in the open circuit voltage curve.

[0014] The present invention has the following beneficial effects: The present invention can obtain virtual increments in real time without injecting real current increments or voltage increments, and without performing multiple iterative calculations; and is not restricted by working conditions such as battery charging or discharging. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flow chart of a state of charge estimation method based on virtual incremental injection; Figure 2 This is a block diagram of the principle of the state of charge estimation method based on virtual incremental injection; Figure 3 This is an internal principle block diagram of the first virtual incremental injection module; Figure 4 This is an internal principle block diagram of the second virtual incremental injection module; Figure 5 Estimated state of charge waveform for the battery during the entire charging process with unequal intervals; Figure 6 The waveform for estimating the state of charge of the battery during the entire process of uneven interval discharge. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention are described below to facilitate understanding of the present invention by those skilled in the art. However, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations utilizing the concepts of the present invention are protected.

[0017] like Figure 1 As shown, an embodiment of the present invention provides a method for estimating state of charge based on virtual incremental injection, comprising the following steps S1 to S4: S1. Obtain the current battery current and the battery terminal voltage at the last resting moment, and calculate the current relative remaining state of charge by combining the ampere-hour integration method and the open circuit voltage method; 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 last rest moment, and calculates the relative remaining state of charge at the current moment by combining the ampere-hour integration method and the open circuit voltage method, including: According to the battery terminal voltage at the last static moment, the relative residual state of charge at the last static moment is determined by the battery open circuit voltage curve; According to the current battery current, the change in the battery state of charge at the current moment is calculated by combining 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.

[0018] In this embodiment, the open circuit voltage curve represents the relationship between the battery open circuit voltage (OCV) and the battery state of charge (SOC). The open circuit voltage curve is hereinafter referred to as the OCV curve.

[0019] The open circuit voltage-ampere-hour integration method uses the open circuit voltage method to obtain the battery's state of charge when the battery is at rest. That is, the battery terminal voltage Vrest when the battery is fully rested is obtained as the battery's open circuit voltage. The relative remaining state of charge SOCrest at the rest time is obtained by querying the OCV curve. The calculation formula is: , The open circuit voltage-ampere-hour integration method uses the ampere-hour integration method to obtain the change in the battery's state of charge when the battery is charging or discharging. The calculation formula is: , Among them, SOCvar is the change of state of charge, is the charge and discharge time, is the battery current, and Qocv is the total battery capacity corresponding to the OCV curve.

[0020] The current relative remaining state of charge 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, , Among them, 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.

[0021] S2. Setting the maximum and minimum values ​​of the battery terminal voltage as control targets of the first virtual incremental injection module and the second virtual incremental injection module, and using a proportional-integral controller to predict the maximum and minimum values ​​of the relative remaining state of charge at the current moment; In an optional embodiment of the present invention, step S2 sets the maximum value of the battery terminal voltage as the control target of the first virtual incremental injection module, and uses a proportional-integral controller to predict the maximum value of the relative residual state of charge at the current moment, including: Setting the maximum value of the battery terminal voltage as the control target of the first virtual increment injection module, and using a proportional-integral controller to obtain the virtual increment to be injected by the first virtual increment injection module in real time; The maximum value of the relative residual state of charge at the current moment is predicted according to the virtual increment to be injected by the first virtual increment injection module and the relative residual state of charge at the current moment.

[0022] In this embodiment, since the polarization voltage in the battery equivalent circuit model cannot be measured and the polarization impedance introduces more battery parameters to be measured, a battery management system that is more sensitive to cost will use an equivalent internal resistance model as the battery equivalent circuit model. Therefore, taking this model as an example, the calculation formula is: , Where V is the terminal voltage of the battery, R0 is the equivalent internal resistance of the battery, and VOC (SOC) represents the open circuit voltage of the battery corresponding to the current state of charge SOC in the OCV curve.

[0023] 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 charge stored between the maximum and minimum battery terminal voltage values ​​as the full-charge capacity. This difference in the definition of full-charge capacity can lead to differences between the estimated battery remaining state of charge (SOC) and the user's actual expected SOC. Therefore, it is necessary to consider the operating range of the battery terminal voltage in addition to the open-circuit voltage-ampere-hour integration method.

[0024] like Figure 3 The figure shows the internal principle block diagram of the first virtual increment injection module. This module uses the maximum value of the battery terminal voltage set by the user as the control target and uses a proportional-integral controller to obtain the virtual increment to be injected in real time. Specifically: , , Among them, SOCinc0 is the virtual increment to be injected by the first virtual increment injection module, kp0 is the proportional gain coefficient of the first virtual increment injection module, e0 is the control error of the first virtual increment injection module, ki0 is the integral gain coefficient of the first virtual increment injection module, Vmax is the set maximum value of the battery terminal voltage, and Vpre0 is the battery terminal voltage estimated by the first virtual increment injection module.

[0025] Combined with the current relative remaining state of charge of the battery, the maximum value of the relative remaining state of charge of the battery is predicted, specifically: , Wherein, SOCpre0 is the maximum 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 SOCinc0 is the virtual increment to be injected by the first virtual increment injection module.

[0026] In the OCV curve, the battery open circuit voltage Vocv0 corresponding to the state of charge SOCpre0 is: , The proportional-integral controller automatically adjusts the injected virtual increment SOCinc0 so that the estimated battery terminal voltage Vpre0 is: , Among them, Ichg is the size of the charging current.

[0027] In the first virtual increment injection module, the proportional-integral controller automatically and continuously 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 SOCpre0 of the battery relative remaining state of charge predicted by the first virtual increment injection module will also tend to converge to the maximum value of the actual battery relative remaining state of charge corresponding to the battery terminal voltage Vmax.

[0028] 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 residual state of charge at the current moment, including: Setting the minimum value of the battery terminal voltage as the control target of the second virtual increment injection module, and using a proportional-integral controller to obtain the virtual increment to be injected by the second virtual increment injection module in real time; The minimum value of the relative residual state of charge at the current moment is predicted according to the virtual increment to be injected by the second virtual increment injection module and the relative residual state of charge at the current moment.

[0029] like Figure 4The figure shows the internal principle block diagram of the second virtual increment injection module. This module uses the minimum value of the battery terminal voltage set by the user as the control target and uses a proportional-integral controller to obtain the virtual increment to be injected in real time. Specifically: , , Among them, SOCinc1 is the virtual increment to be injected by the second virtual increment injection module, kp1 is the proportional gain coefficient of the second virtual increment injection module, e1 is the control error of the second virtual increment injection module, ki1 is the integral gain coefficient of the second virtual increment injection module, Vmin is the set minimum value of the battery terminal voltage, and Vpre1 ​​is the battery terminal voltage estimated by the second virtual increment injection module.

[0030] Combined with the current relative remaining state of charge of the battery, the minimum value of the relative remaining state of charge of the battery is predicted, specifically: , 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.

[0031] In the OCV curve, the battery open circuit voltage Vocv1 corresponding to the state of charge SOCpre1 is: , The proportional-integral controller automatically adjusts the injected virtual increment SOCinc1 so that the estimated battery terminal voltage Vpre1 ​​is: , Wherein, Idsg is the magnitude of the discharge current.

[0032] In the second virtual increment injection module, the proportional-integral controller 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 SOCpre1 of the battery relative remaining state of charge predicted by the second virtual increment injection module will also tend to converge to the minimum value of the actual battery relative remaining state of charge corresponding to the battery terminal voltage Vmin.

[0033] S3. Calculating the actual available 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; In an optional embodiment of the present invention, step S3 calculates the actual total available 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: Calculating the remaining capacity of the battery at the current moment according to 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 available 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.

[0034] In this embodiment, if Figure 2 Figure 2 shows a block diagram of the SOC estimation method based on virtual incremental injection. Based on the outputs of the two virtual incremental injection modules and the current relative remaining SOCcur, the remaining battery capacity and the actual total available battery capacity stored between the battery terminal voltages Vmax and Vmin can be calculated.

[0035] This embodiment calculates the remaining capacity of the battery at the current moment 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, specifically: , Among them, 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 capacity of the battery in the battery open circuit voltage curve.

[0036] This embodiment calculates the actual total available capacity of the battery based on the maximum and minimum values ​​of the current relative remaining state of charge, specifically: , Among them, Qtotal is the total capacity actually available for 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 capacity of the battery in the open circuit voltage curve.

[0037] S4. Calculate the actual remaining state of charge of the battery at the current moment based on the actual total available capacity of the battery and the remaining capacity of the battery at the current moment.

[0038] In an optional embodiment of the present invention, step S4 can calculate the actual remaining state of charge SOCact of the battery at the current moment based on the remaining capacity Qrem of the battery at the current moment and the actual total available capacity Qtotal of the battery. The calculation formula is: , The ratio of the actual available total capacity of the battery to the total capacity corresponding to the OCV curve is: , When the ratio is greater than 1, it means that the actual total available battery capacity, corresponding to the user-set maximum and minimum battery terminal voltages, exceeds the total capacity corresponding to the OCV curve. If the total capacity exceeds 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), causing errors in the open circuit voltage-ampere-hour integration method. In this case, the user should be prompted to modify the maximum and minimum battery terminal voltage settings. 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.

[0039] Taking the intermittent charge and discharge conditions of 18650 lithium batteries as an example, Figure 5 It is the state of charge estimation waveform during the whole process of battery unequal interval charging. Figure 6 This is the estimated waveform of the state of charge during the entire process of battery unequal interval discharge. Figure 5 and Figure 6 In the figure, the corresponding waveforms from top to bottom are the battery terminal voltage, battery current and estimated battery state of charge. Figure 5 and Figure 6 It can be seen that during the intermittent charging or discharging of the battery, the state of charge estimation method has good dynamic and steady-state performance.

[0040] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts 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, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0041] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1The function specified in one or more boxes.

[0042] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0043] Specific embodiments are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core ideas. At the same time, for those skilled in the art, according to the ideas of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.

[0044] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and it should be understood that the scope of protection of the present invention is not limited to such specific descriptions and embodiments. Those skilled in the art can make various other specific variations and combinations based on the technical teachings disclosed in the present invention without departing from the essence of the present invention, and such variations and combinations are still within the scope of protection of the present invention.

Claims

1. A state of charge estimation method based on virtual incremental injection, characterized in that: The following steps are involved: Obtain the current battery current and the battery terminal voltage at the last resting moment, and calculate the current relative remaining state of charge by combining the ampere-hour integration method and the open-circuit voltage method; Setting the maximum and minimum values ​​of the battery terminal voltage as control targets of the first virtual incremental injection module and the second virtual incremental injection module, and using a proportional-integral controller to predict the maximum and minimum values ​​of the relative remaining state of charge at the current moment; Calculate the actual 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; The actual remaining state of charge of the battery at the current moment is calculated based on the actual total capacity of the battery and the remaining capacity of the battery at the current moment.

2. The method for state of charge estimation based on virtual incremental injection according to claim 1, characterized in that: Obtain the current battery current and the battery terminal voltage at the last resting moment, and calculate the current relative remaining state of charge by combining the ampere-hour integration method and the open-circuit voltage method, including: According to the battery terminal voltage at the last static moment, the relative residual state of charge at the last static moment is determined by the battery open circuit voltage curve; According to the current battery current, the change in the battery state of charge at the current moment is calculated by combining 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 state of charge estimation based on virtual incremental injection according to claim 2, characterized in that: The current relative remaining state of charge 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, ， Among them, 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 state of charge estimation based on virtual incremental injection according to claim 1, characterized in that: The maximum value of the battery terminal voltage is set as the control target of the first virtual incremental injection module, and the proportional-integral controller is used to predict the maximum value of the relative residual state of charge at the current moment, including: Setting the maximum value of the battery terminal voltage as the control target of the first virtual increment injection module, and using a proportional-integral controller to obtain the virtual increment to be injected by the first virtual increment injection module in real time; The maximum value of the relative residual state of charge at the current moment is predicted according to the virtual increment to be injected by the first virtual increment injection module and the relative residual state of charge at the current moment.

5. The method for state of charge estimation based on virtual incremental injection according to claim 4, characterized in that: 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: ， ， Among them, SOCinc0 is the virtual increment to be injected by the first virtual increment injection module, kp0 is the proportional gain coefficient of the first virtual increment injection module, e0 is the control error of the first virtual increment injection module, ki0 is the integral gain coefficient of the first virtual increment injection module, Vmax is the set maximum value of the battery terminal voltage, and Vpre0 is the battery terminal voltage estimated by the first virtual increment injection module.

6. The method for state of charge estimation based on virtual incremental injection according to claim 4, characterized in that: The maximum value of the relative residual state of charge 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 state of charge at the current moment, specifically: ， Wherein, SOCpre0 is the maximum 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 SOCinc0 is the virtual increment to be injected by the first virtual increment injection module.

7. The method for state of charge estimation based on virtual incremental injection according to claim 1, characterized in that: The minimum value of the battery terminal voltage is set as the control target of the second virtual incremental injection module, and the proportional-integral controller is used to predict the minimum value of the relative remaining state of charge at the current moment, including: Setting the minimum value of the battery terminal voltage as the control target of the second virtual increment injection module, and using a proportional-integral controller to obtain the virtual increment to be injected by the second virtual increment injection module in real time; The minimum value of the relative residual state of charge at the current moment is predicted according to the virtual increment to be injected by the second virtual increment injection module and the relative residual state of charge at the current moment.

8. The method for state of charge estimation based on virtual incremental injection according to claim 1, characterized in that: The actual total available 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, including: Calculating the remaining capacity of the battery at the current moment according to 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 available 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.

9. The method for state of charge estimation based on virtual incremental injection according to claim 8, characterized in that: The remaining capacity of the battery at the current moment is calculated based on the minimum value of the current relative remaining state of charge and the current relative remaining state of charge, specifically: ， Among them, 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 capacity of the battery in the battery open circuit voltage curve.

10. The method for state of charge estimation based on virtual incremental injection according to claim 8, characterized in that: The actual available total capacity of the battery is calculated based on the maximum and minimum values ​​of the current relative remaining state of charge, specifically: ， Among them, Qtotal is the total capacity actually available for 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 capacity of the battery in the battery open circuit voltage curve.

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