Abnormal monitoring and alarming method, system and device for energy storage converter

Abstract

The invention belongs to the technical field of energy storage converter monitoring, and particularly relates to an abnormal monitoring and alarming method, system and device for an energy storage converter, and the method comprises the steps: S1, obtaining the operation parameters of the converter; s2, calculating a power balance difference based on the total power of the AC and DC sides and a loss model, and judging that the system is abnormal if the power balance difference exceeds a threshold value; the deviation degree between the expected current and the actual current of each battery cluster is calculated, and a specific abnormal battery cluster is positioned and an alarm is given; s3, screening and sorting healthy battery clusters according to security constraints and comprehensive priority scores to form a priority standby sequence; and S4, determining the power needing to be transferred, and intelligently redistributing the power to the healthy battery cluster according to the sequence and the battery safety margin. According to the method, accurate positioning and intelligent power reconstruction of the abnormal battery cluster are realized, and the fault diagnosis accuracy and operation availability of the energy storage system are improved.

Description

Technical Field

[0001] This invention belongs to the field of energy storage converter monitoring technology, specifically relating to an abnormal monitoring and alarm method, system and device for energy storage converters. Background Technology

[0002] As the core power conversion unit of an electrochemical energy storage system, the reliability of the energy storage converter directly affects the safety and efficiency of the entire energy storage power station. Energy storage converters typically consist of multiple batteries connected in parallel for power supply and energy storage, achieving high capacity and high power output.

[0003] Currently, the main technical shortcomings of anomaly monitoring methods for energy storage converters are as follows: Existing methods mostly rely on total voltage and total current thresholds on the AC or DC side for alarms, such as DC overvoltage and AC overcurrent. However, they cannot accurately pinpoint which of the many batteries is the source of the anomaly, leading to alarm delays or even missed alarms, which brings great difficulties to fault diagnosis.

[0004] Most methods use fixed current and voltage thresholds, failing to fully consider the physical characteristics of energy storage converters under different charging and discharging conditions, where the energy flow direction and current direction are completely different, resulting in insufficient sensitivity under specific conditions.

[0005] After an alarm is triggered, manual intervention or simple shutdown protection is usually required, which leads to a loss of system availability. This results in wasted capacity and may cause the entire energy storage converter to shut down due to a single point of failure, resulting in significant losses. Summary of the Invention

[0006] The purpose of this invention is to provide a method, system, and device for abnormal monitoring and alarm of energy storage converters.

[0007] A method for abnormal monitoring and alarm of an energy storage converter includes the following steps: S1. Obtain the charging and discharging status, DC current, DC voltage, AC voltage, and AC current of the energy storage converter; S2. Calculate the total AC power based on the AC voltage and AC current of the energy storage converter, calculate the total DC power based on the DC voltage and DC current, estimate the power loss through the preset energy storage converter loss model, and calculate the power balance difference index based on the total AC power, the total DC power and the power loss. When the power balance difference index exceeds the first threshold, determine that the current energy storage converter is an abnormal energy storage converter. Based on the total power of the DC side of the abnormal energy storage converter and the voltage of each battery, the expected DC current of each battery is calculated. Based on the expected DC current of each battery, the DC current deviation of each battery is calculated. Batteries whose absolute value of DC current deviation exceeds the second threshold and whose deviation from the expected DC current in one direction is unidirectional within m consecutive time windows are identified as abnormal batteries and an alarm is triggered. S3. Select batteries that meet the first-level safety constraints from the batteries other than the abnormal batteries in the energy storage converter to form a primary reserve pool. Calculate the comprehensive priority score for each battery in the primary reserve pool. Sort the batteries in the primary reserve pool in descending order according to the comprehensive priority score to form a priority reserve sequence. S4. Based on the power balance difference index and DC current deviation, determine the power to be transferred from the abnormal battery. According to the priority backup sequence, the power increment allocated to the current backup battery shall not exceed its maximum safe power increment calculated based on the real-time status. Repeat this process until all the power to be transferred is allocated or the priority backup sequence is traversed.

[0008] In S2, power loss is estimated through a preset energy storage converter loss model. Specifically, the total measured loss of the energy storage converter is measured at different load points. The theoretical loss is calculated based on conduction loss, switching loss, and auxiliary loss. The theoretical loss is compared and calibrated with the total measured loss to form a two-dimensional lookup table. The power loss is obtained in real time by looking up the table based on the current total AC power and total DC power.

[0009] S2 calculates the power balance difference index based on the total AC power, total DC power, and power loss. Specifically, when the energy storage converter is in the discharge state, the absolute value of the total AC power plus power loss minus the total DC power is the root mean square of the power balance difference index within the sliding time window. When the energy storage converter is in discharge mode, the absolute value of the total power on the DC side plus power loss minus the total power on the AC side, within the sliding time window, is the root mean square index of the power balance difference.

[0010] Based on the current total power and the voltage of each battery, S2 calculates the expected DC current of each battery: , in, This represents the total power on the DC side. Let be the DC voltage of the i-th battery. Let represent the battery health of the i-th battery.

[0011] Based on the expected current of each battery, S2 calculates the DC current deviation of each battery: ,in, It is direct current. Let be the expected DC current of the i-th battery. Let be the maximum allowable charge / discharge current for the i-th battery.

[0012] The first level of safety constraints in S3 include: the battery's state of charge is within a preset safety window; the battery's DC current is less than the expected DC current; the battery's health status is higher than a preset threshold; and the battery's temperature is within a preset normal range.

[0013] The formula for calculating the overall priority score in S3 is as follows: in, In a charged state, For a healthy state, For real-time margin, The abnormal proportions are represented by w1, w2, w3, and w4, which are preset weighting coefficients and are all positive numbers.

[0014] In S4, the power to be transferred from the abnormal battery is determined based on the power balance difference index and the current deviation. Specifically, if the proportion of the power balance difference index exceeding the first threshold is less than the first proportion, and the proportion of the DC current deviation exceeding the second threshold is less than the second proportion, the power to be transferred is set as the power balance difference index. If the proportion of the power balance difference index exceeding the first threshold is greater than the third proportion, the power to be transferred will be set to the power of the abnormal battery before the fault. If the proportion of the power balance difference index exceeding the first threshold is between the first proportion and the second proportion, then the power to be transferred is the product of the power of the abnormal battery before the fault and the relevant proportional coefficient.

[0015] An abnormality monitoring and alarm system for an energy storage converter, used to implement the aforementioned abnormality monitoring and alarm method for an energy storage converter, includes: The data acquisition module acquires the charging and discharging status, DC current, DC voltage, AC voltage, and AC current of the energy storage converter. The anomaly detection module calculates the total AC power based on the AC voltage and AC current of the energy storage converter, calculates the total DC power based on the DC voltage and DC current, estimates the power loss through a preset energy storage converter loss model, and calculates the power balance difference index based on the total AC power, total DC power, and power loss. When the power balance difference index exceeds the first threshold, the current energy storage converter is determined to be an abnormal energy storage converter. Based on the total power of the DC side of the abnormal energy storage converter and the voltage of each battery, the expected DC current of each battery is calculated. Based on the expected DC current of each battery, the DC current deviation of each battery is calculated. Batteries whose absolute value of DC current deviation exceeds the second threshold and whose deviation from the expected DC current in one direction is unidirectional within m consecutive time windows are identified as abnormal batteries and an alarm is triggered. The priority standby sequence calculation module selects batteries that meet the first-level safety constraints from the batteries other than the abnormal batteries in the energy storage converter to form a primary standby pool. It calculates a comprehensive priority score for each battery in the primary standby pool and sorts the batteries in the primary standby pool in descending order according to the comprehensive priority score to form a priority standby sequence. The allocation module determines the power to be transferred from the abnormal battery based on the power balance difference index and DC current deviation. According to the priority backup sequence, the power increment allocated to the current backup battery does not exceed its maximum safe power increment calculated based on the real-time status. This process is repeated until all the power to be transferred is allocated or the priority backup sequence is traversed.

[0016] An abnormal monitoring and alarm device for an energy storage converter includes a processor and a memory, wherein the processor executes a computer program stored in the memory to implement an abnormal monitoring and alarm method for the energy storage converter.

[0017] Compared with existing technologies, the energy storage converter anomaly monitoring and alarm method provided by this invention has the following significant advantages: This invention employs a dual diagnostic mechanism of coarse positioning based on total power imbalance and fine positioning of individual batteries. It detects anomalies from total power imbalance and then accurately identifies which battery is malfunctioning by comparing the actual DC current of each battery with the expected current calculated based on real-time status, thus shortening the troubleshooting time.

[0018] This invention establishes an accurate power balance model that includes converter losses, enabling the detection of minute power inconsistencies and providing early warnings, thus improving the sensitivity and reliability of fault detection. Simultaneously, the calculation of current deviation for each cluster fully considers the real-time state of the batteries, making the expected current value more consistent with physical reality and avoiding misjudgments caused by differences in battery status, significantly improving detection accuracy.

[0019] This invention goes beyond simply monitoring and alarming. Upon identifying an abnormal battery, it can also select the most suitable backup battery from healthy batteries and safely and orderly transfer the power tasks of the abnormal battery to it. This process is achieved through rigorous multi-level safety screening and quantified power allocation rules, ensuring the safety and smoothness of the transfer process. Even in the event of partial unit failure, it can maximize system output, significantly improving the availability and reliability of the energy storage system. Detailed Implementation

[0020] To further understand the content of this invention, the invention will be described in detail with reference to the embodiments.

[0021] This invention relates to an anomaly monitoring and alarm method for an energy storage converter, comprising the following steps: S1. Obtain the charging and discharging status, DC current, DC voltage, AC voltage, and AC current of the energy storage converter.

[0022] S2. Calculate the total AC power based on the AC voltage and AC current of the energy storage converter, calculate the total DC power based on the DC voltage and DC current, estimate the power loss through the preset energy storage converter loss model, and calculate the power balance difference index based on the total AC power, total DC power and power loss. When the power balance difference index exceeds the first threshold, determine that the current energy storage converter is an abnormal energy storage converter.

[0023] Based on the total power of the DC side of the abnormal energy storage converter and the voltage of each battery, the expected DC current of each battery is calculated. Based on the expected DC current of each battery, the DC current deviation of each battery is calculated. Batteries whose absolute value of DC current deviation exceeds the second threshold and whose deviation from the expected DC current in one direction is unidirectional within m consecutive time windows are identified as abnormal batteries and an alarm is triggered.

[0024] Specifically, the total AC power is calculated based on the AC voltage and AC current of the energy storage converter, and the total DC power is calculated based on the DC voltage and DC current. The power loss is estimated through a preset energy storage converter loss model. The specific operation is as follows: the measured total loss of the energy storage converter is measured at different load points, the theoretical loss is calculated based on the conduction loss, switching loss and auxiliary loss, the theoretical loss is compared and calibrated with the measured total loss to form a two-dimensional lookup table, and the power loss is obtained in real time by looking up the table according to the current total AC power and total DC power.

[0025] Furthermore, the measured total loss also includes conduction loss, switching loss, and auxiliary loss. Conduction loss mainly consists of the on-state loss of the insulated-gate dual transistor (IGDT) and the anti-parallel diode. Theoretical losses can be obtained from their respective datasheets, while the measured total loss can be calculated based on the average and effective values ​​of the DC current flowing through the IGDT and the diode. Switching loss is the loss generated by the IGDT turning on and off, and the diode's reverse recovery. Theoretical losses are calculated according to their respective manuals / instructions. When calculating the measured total loss, in each switching cycle, the single switching energy is obtained based on the real-time sampling or estimation of the current of the device to be switched and the current DC voltage. This energy is then multiplied by the switching frequency to obtain the average switching loss of the device. Finally, the losses of all switching devices are summed. Auxiliary losses include the power consumed by the controller, heat dissipation, pump, drive circuit, and filter inductor core losses. This part is relatively fixed and can be regarded as a constant.

[0026] The theoretical loss is compared and calibrated with the measured total loss to form a two-dimensional power loss lookup table based on the total AC power and the total DC power. The power loss is obtained in real time by looking up the table according to the current total AC power and the total DC power.

[0027] The comparison and calibration process includes: comparing the theoretical loss and measured total loss corresponding to the same AC-side total power and DC-side total power, calculating the difference, obtaining the average difference, forming a preliminary lookup table of AC-side total power and DC-side total power and measured total loss, calibrating the missing measured total loss, and obtaining a complete preliminary lookup table by adding / subtracting the average difference from the theoretical loss. The results obtained by adding / subtracting the average difference from the measured loss and the theoretical loss are collectively referred to as power loss, and the completed preliminary lookup table is used as a two-dimensional lookup table of power loss.

[0028] Based on the total AC power, total DC power, and power loss, the power balance difference index is calculated. Specifically, when the energy storage converter is in the discharge state, the absolute value of the total AC power plus power loss minus the total DC power is the root mean square of the power balance difference index within the sliding time window. When the energy storage converter is in discharge mode, the absolute value of the total power on the DC side plus power loss minus the total power on the AC side, within the sliding time window, is the root mean square index of the power balance difference.

[0029] When the power balance difference index exceeds the first threshold, the current energy storage converter is determined to be an abnormal energy storage converter.

[0030] Based on the total DC-side power of the abnormal energy storage converter and the voltage of each battery, calculate the expected DC current of each battery. , in, This represents the total power on the DC side. Let be the DC voltage of the i-th battery. Let represent the battery health of the i-th battery.

[0031] Calculate the DC current deviation of each battery: ,in, It is direct current. Let be the expected DC current of the i-th battery. Let be the maximum allowable charge / discharge current for the i-th battery. The maximum allowable charge / discharge current is not 0.

[0032] Batteries whose absolute value of DC current deviation exceeds the second threshold and whose DC current deviates unidirectionally from the expected DC current within m consecutive time windows are identified as abnormal batteries and an alarm is triggered.

[0033] For example, if the deviation is 20 and the second threshold is 15, and the values ​​are 23, 28, 30... within a consecutive m time window, then it is determined to be an abnormal battery and an alarm is triggered.

[0034] S3. Select batteries that meet the first-level safety constraints from the batteries other than the abnormal batteries in the energy storage converter to form a primary reserve pool. Calculate the comprehensive priority score for each battery in the primary reserve pool. Sort the batteries in the primary reserve pool in descending order according to the comprehensive priority score to form a priority reserve sequence.

[0035] Furthermore, batteries that meet the first-level safety constraints are selected to form the primary backup battery. The first-level safety constraints include: the battery's state of charge is within a preset safety window, the battery's DC current is less than the expected DC current, the battery's health status is higher than a preset threshold, and the battery's temperature is within a preset normal range.

[0036] Calculate a comprehensive priority score for each battery in the primary reserve pool. The formula for calculating the comprehensive priority score is as follows: in, In a charged state, For a healthy state, For real-time margin, The abnormal proportions are represented by w1, w2, w3, and w4, which are preset weighting coefficients and are all positive numbers.

[0037] Furthermore, the aforementioned In a charged state, For a healthy state, For real-time margin, For specific calculation methods of the abnormality ratio, please refer to the following: In discharge mode: ,in, , , These represent the state of charge (SOC) of the i-th battery, the minimum SOC of the battery, and the intermediate SOC of the battery, respectively. Not equal to During discharge, batteries with high SOC are encouraged to output more power.

[0038] This encourages healthy batteries to take on more tasks, achieves load balancing, and slows down overall aging; the same applies during charging.

[0039] This directly reflects how much additional power the cluster can safely handle at present. The larger the margin, the higher the score; this weight, w3, is usually the largest.

[0040] , This refers to the number of times the battery has been recently identified as abnormal. If a cluster of cells has recently experienced abnormalities, its reliability is questionable even if the current parameters are normal. The same applies when charging.

[0041] In charging mode: ,in, The battery's maximum state of charge, Not equal to .

[0042] .

[0043] The batteries in the primary reserve pool are sorted in descending order based on their comprehensive priority scores to form a priority reserve sequence.

[0044] S4. Based on the power balance difference index and DC current deviation, determine the power to be transferred from the abnormal battery. According to the priority backup sequence, the power increment allocated to the current backup battery shall not exceed its maximum safe power increment calculated based on the real-time status. Repeat this process until all the power to be transferred is allocated or the priority backup sequence is traversed.

[0045] Based on the power balance difference index and current deviation, the power to be transferred from the abnormal battery is determined. Specifically: if the proportion of the power balance difference index exceeding the first threshold is less than a first proportion, and the proportion of the DC current deviation exceeding the second threshold is less than a second proportion, the power to be transferred is set as the power balance difference index. This indicates that only a slight power imbalance has occurred, possibly due to slight aging of a battery, a slight increase in contact resistance, etc. In this case, setting the power to be transferred as the power balance difference index only transfers the portion of power that the system cannot currently balance. This is the most economical and least impactful strategy. If the battery only experiences a slight performance degradation, this operation is sufficient to restore balance, and the battery can continue to operate at a reduced power level.

[0046] If the proportion of the power balance difference index exceeding the first threshold is greater than the third proportion, the power to be transferred is set to the power of the abnormal battery before the failure. This indicates that the battery has basically lost its function, such as a blown fuse, a disconnected contactor, or a serious internal fault. In this case, the power to be transferred is directly set to the power of the abnormal battery before the failure, and the battery is judged to be completely failed. All its original tasks are transferred. This is the most thorough strategy.

[0047] If the proportion of the power balance difference index exceeding the first threshold is between the first proportion and the second proportion, then the power to be transferred is the product of the power of the abnormal battery before the fault and the relevant proportional coefficient. If the balance difference index continues to increase slowly over multiple control cycles, this is usually a sign of device aging and deteriorating heat dissipation. We cannot wait for it to fail completely; we must intervene in time to smoothly transfer most of the load before the fault completely breaks out.

[0048] Additionally, if the balance difference index drops rapidly or fluctuates drastically, it may be a precursor to intermittent contact or drive failure. It is extremely unstable and, for safety reasons, is considered to be on the verge of a complete failure. In this case, the power to be transferred is set to the power of the abnormal battery before the failure.

[0049] After determining the power to be transferred from the faulty battery, the power increment allocated to the current backup battery, according to the priority backup sequence, shall not exceed its maximum safe power increment calculated based on the real-time status. Specifically, for the primary backup battery in the priority backup sequence, it is necessary to determine in real time how much additional power it can safely accept, and this calculation strictly distinguishes between charge and discharge states.

[0050] First, a boundary is defined for the charging / discharging mode and battery state: in the discharging mode, the maximum discharge current limit issued by the BMS is used to calculate the additional discharge power at the current current level; in the charging mode, the maximum charging current limit is used to calculate the additional charging power.

[0051] Secondly, based on the power increment of the battery health boundary, taking the discharge mode as an example, the charging mode is logically symmetrical: calculate the power required to reduce the current battery health to the safe lower limit of battery health.

[0052] Convert this power into the duration that can be safely operated at the current power level, ensuring that there is still a time margin of at least T hours after taking on additional tasks, and avoiding instantaneous bottoming out.

[0053] When making the final determination, the minimum power increment calculated from all boundaries is taken, and a derating factor is applied.

[0054] If the power to be transferred is fully allocated, its original task is taken over by one or more batteries in the priority backup sequence, and the total output / input capability of the energy storage converter remains unchanged, thus achieving fault tolerance.

[0055] If the priority backup sequence has been exhausted and the power to be transferred has not yet been allocated, all healthy backup battery clusters have reached their real-time safety boundaries and cannot take on any more additional power, and an alarm is sent to the higher-level energy management system.

[0056] An abnormal monitoring and alarm system for an energy storage converter is provided to implement the aforementioned abnormal monitoring and alarm method for an energy storage converter, comprising: a data acquisition module for acquiring the charging and discharging status, DC current, DC voltage, AC voltage, and AC current of the energy storage converter; The anomaly detection module calculates the total AC power based on the AC voltage and AC current of the energy storage converter, calculates the total DC power based on the DC voltage and DC current, estimates the power loss through a preset energy storage converter loss model, and calculates the power balance difference index based on the total AC power, total DC power, and power loss. When the power balance difference index exceeds the first threshold, the current energy storage converter is determined to be an abnormal energy storage converter. Based on the total power of the DC side of the abnormal energy storage converter and the voltage of each battery, the expected DC current of each battery is calculated. Based on the expected DC current of each battery, the DC current deviation of each battery is calculated. Batteries whose absolute value of DC current deviation exceeds the second threshold and whose deviation from the expected DC current in one direction is unidirectional within m consecutive time windows are identified as abnormal batteries and an alarm is triggered. The priority standby sequence calculation module selects batteries that meet the first-level safety constraints from the batteries other than the abnormal batteries in the energy storage converter to form a primary standby pool. It calculates a comprehensive priority score for each battery in the primary standby pool and sorts the batteries in the primary standby pool in descending order according to the comprehensive priority score to form a priority standby sequence. The allocation module determines the power to be transferred from the abnormal battery based on the power balance difference index and DC current deviation. According to the priority backup sequence, the power increment allocated to the current backup battery does not exceed its maximum safe power increment calculated based on the real-time status. This process is repeated until all the power to be transferred is allocated or the priority backup sequence is traversed.

[0057] An abnormal monitoring and alarm device for an energy storage converter includes a processor and a memory, wherein the processor executes a computer program stored in the memory to implement an abnormal monitoring and alarm method for the energy storage converter.

Claims

1. A method for abnormal monitoring and alarm of an energy storage converter, characterized in that, Includes the following steps: S1. Obtain the charging and discharging status, DC current, DC voltage, AC voltage, and AC current of the energy storage converter; S2. Calculate the total AC power based on the AC voltage and AC current of the energy storage converter, calculate the total DC power based on the DC voltage and DC current, estimate the power loss through the preset energy storage converter loss model, and calculate the power balance difference index based on the total AC power, the total DC power and the power loss. When the power balance difference index exceeds the first threshold, determine that the current energy storage converter is an abnormal energy storage converter. Based on the total power of the DC side of the abnormal energy storage converter and the voltage of each battery, the expected DC current of each battery is calculated. Based on the expected DC current of each battery, the DC current deviation of each battery is calculated. Batteries whose absolute value of DC current deviation exceeds the second threshold and whose deviation from the expected DC current in one direction is unidirectional within m consecutive time windows are identified as abnormal batteries and an alarm is triggered. S3. Select batteries that meet the first-level safety constraints from the batteries other than the abnormal batteries in the energy storage converter to form a primary reserve pool. Calculate the comprehensive priority score for each battery in the primary reserve pool. Sort the batteries in the primary reserve pool in descending order according to the comprehensive priority score to form a priority reserve sequence. S4. Based on the power balance difference index and DC current deviation, determine the power to be transferred from the abnormal battery. According to the priority backup sequence, the power increment allocated to the current backup battery shall not exceed its maximum safe power increment calculated based on the real-time status. Repeat this process until all the power to be transferred is allocated or the priority backup sequence is traversed.

2. The abnormal monitoring and alarm method for an energy storage converter according to claim 1, characterized in that, In S2, power loss is estimated through a preset energy storage converter loss model. Specifically, the total measured loss of the energy storage converter is measured at different load points. The theoretical loss is calculated based on conduction loss, switching loss, and auxiliary loss. The theoretical loss is compared and calibrated with the total measured loss to form a two-dimensional lookup table. The power loss is obtained in real time by looking up the table based on the current total AC power and total DC power.

3. The abnormal monitoring and alarm method for an energy storage converter according to claim 1, characterized in that, S2 calculates the power balance difference index based on the total AC power, total DC power, and power loss. Specifically, when the energy storage converter is in the discharge state, the absolute value of the total AC power plus power loss minus the total DC power is the root mean square of the power balance difference index within the sliding time window. When the energy storage converter is in discharge mode, the absolute value of the total power on the DC side plus power loss minus the total power on the AC side, within the sliding time window, is the root mean square index of the power balance difference.

4. The abnormal monitoring and alarm method for an energy storage converter according to claim 1, characterized in that, Based on the current total power and the voltage of each battery, S2 calculates the expected DC current of each battery: , in, This represents the total power on the DC side. Let be the DC voltage of the i-th battery. Let represent the battery health of the i-th battery.

5. The abnormal monitoring and alarm method for an energy storage converter according to claim 1, characterized in that, Based on the expected current of each battery, S2 calculates the DC current deviation of each battery: ,in, It is direct current. Let be the expected DC current of the i-th battery. Let be the maximum allowable charge / discharge current for the i-th battery.

6. The abnormal monitoring and alarm method for an energy storage converter according to claim 1, characterized in that, The first level of safety constraints in S3 include: the battery's state of charge is within a preset safety window; the battery's DC current is less than the expected DC current; the battery's health status is higher than a preset threshold; and the battery's temperature is within a preset normal range.

7. The abnormal monitoring and alarm method for an energy storage converter according to claim 1, characterized in that, The formula for calculating the overall priority score in S3 is as follows: in, In a charged state, For a healthy state, For real-time margin, The abnormal proportions are represented by w1, w2, w3, and w4, which are preset weighting coefficients and are all positive numbers.

8. The abnormal monitoring and alarm method for an energy storage converter according to claim 1, characterized in that, In S4, the power to be transferred from the abnormal battery is determined based on the power balance difference index and the current deviation. Specifically, if the proportion of the power balance difference index exceeding the first threshold is less than the first proportion, and the proportion of the DC current deviation exceeding the second threshold is less than the second proportion, the power to be transferred is set as the power balance difference index. If the proportion of the power balance difference index exceeding the first threshold is greater than the third proportion, the power to be transferred will be set to the power of the abnormal battery before the fault. If the proportion of the power balance difference index exceeding the first threshold is between the first proportion and the second proportion, then the power to be transferred is the product of the power of the abnormal battery before the fault and the relevant proportional coefficient.

9. An abnormal monitoring and alarm system for an energy storage converter, used to implement the abnormal monitoring and alarm method for an energy storage converter as described in any one of claims 1-8, characterized in that, include: The data acquisition module acquires the charging and discharging status, DC current, DC voltage, AC voltage, and AC current of the energy storage converter. The anomaly detection module calculates the total AC power based on the AC voltage and AC current of the energy storage converter, calculates the total DC power based on the DC voltage and DC current, estimates the power loss through a preset energy storage converter loss model, and calculates the power balance difference index based on the total AC power, total DC power, and power loss. When the power balance difference index exceeds the first threshold, the current energy storage converter is determined to be an abnormal energy storage converter. Based on the total power of the DC side of the abnormal energy storage converter and the voltage of each battery, the expected DC current of each battery is calculated. Based on the expected DC current of each battery, the DC current deviation of each battery is calculated. Batteries whose absolute value of DC current deviation exceeds the second threshold and whose deviation from the expected DC current in one direction is unidirectional within m consecutive time windows are identified as abnormal batteries and an alarm is triggered. The priority standby sequence calculation module selects batteries that meet the first-level safety constraints from the batteries other than the abnormal batteries in the energy storage converter to form a primary standby pool. It calculates a comprehensive priority score for each battery in the primary standby pool and sorts the batteries in the primary standby pool in descending order according to the comprehensive priority score to form a priority standby sequence. The allocation module determines the power to be transferred from the abnormal battery based on the power balance difference index and DC current deviation. According to the priority backup sequence, the power increment allocated to the current backup battery does not exceed its maximum safe power increment calculated based on the real-time status. This process is repeated until all the power to be transferred is allocated or the priority backup sequence is traversed.

10. An abnormal monitoring and alarm device for an energy storage converter, characterized in that, It includes a processor and a memory, wherein the processor executes a computer program stored in the memory to implement an abnormal monitoring and alarm method for an energy storage converter as described in any one of claims 1-8.

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