Battery power control method based on voltage and SOP limitation

Abstract

The invention discloses a battery power control method based on voltage and SOP limitation. The method comprises a state data collection step; a data processing step; an echelon power boundary calculation step of calculating an echelon power boundary and triggering charging limitation or discharging limitation when the single voltage falls into a charging tail end limitation interval or a discharging tail end limitation interval; an SOP power boundary calculation step: based on the SOP data table of the energy storage battery, calculating the SOP power boundary of charging and discharging in combination with the current state data of the energy storage battery; a comprehensive power boundary calculation step: when the charging limit or the discharging limit is triggered, based on the echelon power boundary and the SOP power boundary of charging and discharging, taking the smaller one as a comprehensive power boundary, and updating the comprehensive power boundary to the EMS / PCS as a power scheduling upper limit value; and a feedback and correction step: monitoring the state of the energy storage battery in real time, and recalculating the echelon power boundary and the SOP power boundary. According to the method, overcharge and overdischarge of the energy storage battery can be avoided, and efficient utilization and long-life operation of the energy storage battery are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of battery energy storage, and particularly to a battery power control method based on voltage and SOP limitation. Background Art

[0002] With the transformation of the global energy structure, battery energy storage has been widely applied in multiple fields such as the user side, the power source side, and the power grid side. Although battery energy storage technology has been relatively mature, there are still certain potential safety hazards. When the EMS / PCS of the energy storage power station fails to judge the state of the energy storage battery in a timely and accurate manner, overcharging and over-discharging are likely to occur, which may further lead to problems such as thermal runaway and short circuit, seriously endangering the stable operation of the energy storage power station. Therefore, how to control the battery power through the BMS of the energy storage battery to ensure the stable, reliable, and long-life operation of the energy storage power station is an issue that needs continuous attention. Summary of the Invention

[0003] The present invention aims to provide a method for the BMS of an energy storage battery to execute battery power control, so as to solve the problem that the EMS / PCS of the energy storage power station fails to judge the state of the energy storage battery in a timely and accurate manner, which easily leads to overcharging and over-discharging, and further avoid problems such as thermal runaway and short circuit caused by overcharging and over-discharging, which seriously endanger the stable operation of the energy storage power station.

[0004] The specific technical solution is as follows:

[0005] 1. A battery power control method based on voltage and SOP limitation, characterized by comprising:

[0006] Step of collecting state data: Collect the current state data of the energy storage battery, including the cell voltage, cell temperature, bus voltage, and bus current;

[0007] Step of data processing: Remove outliers, estimate the SOC, calculate the extreme values of the cell voltage and cell temperature, and judge the abnormal state;

[0008] Step of calculating the cascade power boundary: Detect the cell voltage. When the cell voltage falls into the charging end or discharging end limit interval, calculate the cascade power boundary and trigger the charging limit or discharging limit;

[0009] Step of calculating the SOP power boundary: Based on the SOP data table of the energy storage battery, combine the current state data of the energy storage battery to calculate the SOP power boundary for charging and discharging;

[0010] Step of calculating the comprehensive power boundary: When the charging limit or discharging limit is triggered, based on the cascade power boundary and the SOP power boundary for charging and discharging, take the smaller value as the comprehensive power boundary; update the comprehensive power boundary to the EMS / PCS as the power scheduling upper limit value;

[0011] Feedback and correction steps: Monitor the state of the energy storage battery in real time, and recalculate the cascade power boundary and SOP power boundary.

[0012] Compared with the prior art, the remarkable features of the present invention are as follows:

[0013] 1. Through the cascade limit at the end of charge and discharge, at the end of charge and discharge, according to the system operating conditions, the cascade decline of the charge and discharge power boundary can be realized. In this way, the power boundary can be adjusted more accurately, enabling the energy storage battery to be fully discharged and fully charged, and avoiding triggering overvoltage / undervoltage alarms / protections, maximizing the performance of the energy storage battery, and achieving the efficient utilization and long-life operation of the energy storage battery.

[0014] 2. Based on the SOP look-up table limit, the specifications and operating parameters of the energy storage battery are taken into account, such as factors like internal resistance, thermal effect, voltage drop, etc., to better manage different manufacturers' and specifications' energy storage batteries differently, improving the compatibility of the energy storage system.

[0015] 3. Introduce a feedback and correction link, which can correct the charge and discharge power boundary in real time, avoiding overcharging and over-discharging of the energy storage battery. Description of the Drawings

[0016] Figure 1 is the battery power control flow chart based on voltage and SOP limits of the present invention;

[0017] Figure 2 is the calculation flow chart of the cascade power boundary at the end of charge of the present invention;

[0018] Figure 3 is the calculation flow chart of the cascade power boundary at the end of discharge of the present invention;

[0019] Figure 4 is the calculation flow chart of the charging SOP power boundary of the present invention;

[0020] Figure 5 is the charging SOP data table;

[0021] Figure 6 is the calculation flow chart of the discharging SOP power boundary of the present invention;

[0022] Figure 7 is the discharging SOP data table;

[0023] Figure 8 is the calculation flow chart of the comprehensive charge and discharge power / current boundary of the present invention;

[0024] Figure 9 is the power boundary curve during the charging process;

[0025] Figure 10 is the power boundary curve during the discharging process;

[0026] Figure 11 are the voltage, current, power, and comprehensive power boundary curves during the charging process;

[0027] Figure 12 are the voltage, current, power, and comprehensive power boundary curves during the discharging process. Detailed implementation manners

[0028] To further illustrate each embodiment, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, mainly used to illustrate the embodiments, and can be combined with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation manners.

[0030] The battery power control system involves the following components: energy storage battery, battery management system (BMS), power conversion system (PCS), and energy management system (EMS). The connection relationships between these components include communication connection relationships and energy connection relationships; among them, the communication connection relationship refers to the triangular communication composed of one-way communication between BMS and PCS, two-way communication between BMS and EMS, and two-way communication between PCS and EMS. The energy connection relationship refers to the energy flow between the energy storage battery and the power conversion system. The spatial position relationships of these components are: there is a spatial position for the energy flow between the energy storage battery and the power conversion system (PCS), that is, the energy storage battery is connected to the power conversion system through a DC bus. BMS is deployed on the side of the energy storage battery. There are no strict spatial position requirements for EMS.

[0031] According to the characteristics that the voltage of the energy storage battery changes slowly during the plateau period and changes sharply at the end, the BMS adopts a combined scheme of end echelon limit and SOP limit to limit power.

[0032] Such as Figure 1As shown in the figure, the present invention provides a battery power control method based on voltage and SOP limitation for a battery power control system. According to the characteristics that the voltage of the energy storage battery changes slowly during the plateau period and changes sharply at the end, this method adopts a technical solution combining end echelon limitation and SOP limitation: during the full charge and discharge life cycle, according to the state of the energy storage battery (SOC, temperature, etc.) and the battery specifications, estimate the SOP, and then calculate the charge and discharge power boundaries based on the SOP; when approaching the end of charge and discharge, calculate the charge and discharge echelon power boundaries according to whether the voltage of the energy storage battery falls within the configured limitation interval; then synthesize the SOP power boundary and the echelon power boundary to obtain a reasonable power boundary, which is provided to the EMS / PCS as the upper limit value of power scheduling. For the end charge and discharge echelon limitation interval, one or more limitation intervals can be configured according to the actual project requirements, and the power limitation factor of each interval decreases in echelon.

[0033] Specifically, it includes the following steps:

[0034] (1) Data collection: Collect the state data of the energy storage battery, such as basic data like single-cell voltage, single-cell temperature, bus voltage, bus current, etc.

[0035] (2) Data processing: Process the collected state data, remove outliers, estimate SOC / SOH, calculate the extreme values of single-cell voltage and single-cell temperature, and judge the abnormal state.

[0036] (3) Echelon power boundary calculation: According to the charge and discharge state, determine whether the single-cell voltage falls within the end charge and discharge limitation interval, and calculate the echelon power boundary according to the corresponding strategy. When the single-cell voltage falls within the end charge and discharge limitation interval, charge limitation or discharge limitation will be triggered. The meaning of triggering the limitation is: when the battery runs to the end of charge and discharge, in order to ensure the safe operation of the battery and improve the battery efficiency as much as possible. At the end of charge and discharge, the BMS reduces the charge and discharge power to operate at a certain proportion of the rated power. The actual power boundary is provided for the EMS / PCS to use, and the EMS / PCS will reasonably allocate and control the charge and discharge power of the battery according to the power boundary calculated by the BMS. To avoid the power boundary switching back and forth between multiple values, the SOC change amount is introduced to limit the oscillation of the power boundary.

[0037] (4) SOP power boundary calculation: Based on the SOP mapping table related to the energy storage battery specifications, according to the current state of the energy storage battery (SOC, temperature, etc.), look up the SOC limit strategy in the table, and then calculate the SOP power boundary according to this SOC limit strategy.

[0038] (5) Comprehensive power boundary calculation: Based on the above echelon power boundary and SOP power boundary, take appropriate values according to the actual working conditions as the comprehensive power boundary to protect the energy storage battery to work in a safer state.

[0039] (6) Feedback and correction: The BMS monitors the state of the energy storage battery in real time, recalculates the cascade power boundary and the SOP power boundary, and updates the comprehensive power boundary to the EMS / PCS as the upper limit value of power scheduling.

[0040] The following elaborates on the core processes: cascade power boundary calculation, SOP power boundary calculation, and comprehensive power boundary calculation.

[0041] The following presents a battery power control system with the following parameter configurations to illustrate the processes of cascade power boundary calculation and SOP power calculation.

[0042] Configuration parameters: battery capacity 280 Ah; nominal voltage 3.2 V; system multiple 0.5; number of configured clusters: 20; number of cells in a cluster 15 * 16; charging power limit 2150 kW; discharging power limit 2150 kW.

[0043] The battery cluster cells are connected in series to increase the bus voltage, and the battery clusters are connected in parallel to increase the system capacity.

[0044] 1. Cascade power boundary calculation

[0045] As Figure 2 shown, the charging cascade power boundary calculation process includes the following steps:

[0046] The main task periodically calls the charging end cascade boundary calculation process, determines and calculates the latest cascade power boundary based on the current battery state for subsequent determination and calculation.

[0047] (1) Determine whether the maximum cell voltage falls within the charging end limit interval; when the maximum cell voltage does not fall within the charging end limit interval, execute the normal strategy, calculate the charging end power boundary and the charging end current boundary according to the normal strategy, and update the charging end normal calculation flag; when the maximum cell voltage falls within the charging end limit interval, execute the limit strategy, calculate the charging end power boundary and the charging end current boundary according to the limit strategy, and update the charging end limit calculation flag.

[0048] (2) Under the charging limit trigger state, detect the SOC and determine whether the SOC meets the charging boundary recovery requirement; when the SOC meets the charging boundary recovery requirement, restore the charging end power boundary and the charging end current boundary according to the normal strategy, and update the charging end recovery calculation flag.

[0049] In the above steps, the formula for calculating the charging cascade power / current boundary under the normal strategy is:

[0050] Charging cascade power boundary = (charging power limit / number of configured clusters) * number of closed clusters;

[0051] Charging echelon current boundary = MIN(Rated capacity * Number of closing clusters, Charging echelon power boundary / Total voltage).

[0052] The formula for calculating the charging echelon power / current boundary under the limiting strategy is as follows:

[0053] Charging echelon power boundary = (Charging power limit / Number of configured clusters) * Number of closing clusters * Power limit factor;

[0054] Charging echelon current boundary = MIN(Rated capacity * Number of closing clusters * Current limit factor, Charging echelon power boundary / Total voltage).

[0055] Where MIN() is the minimum value function.

[0056] The following gives a calculation example:

[0057] Assume that the number of closing clusters of the test system is 18 clusters, and the charging end limit interval is configured as follows: Voltage range: [3.45, 3.5); Power limit factor: 0.2; Current limit factor: 0.2; Cancel limit SOC drop of 5%.

[0058] Example A:

[0059] State 1: A certain charging state of the test system is: SOC = 94.9%, Maximum monomer voltage = 3.47V, Total voltage = 832.8V. The maximum monomer voltage falls within the limit interval [3.45, 3.5), then calculate the charging power / current boundary according to the limit interval as follows:

[0060] Charging echelon power boundary = (Charging power limit / Number of configured clusters) * Number of closing clusters * Power limit factor = (2150 / 20) * 18 * 0.2 = 387kW.

[0061] Charging echelon current boundary = MIN(Rated capacity * Number of closing clusters * Current limit factor, Charging echelon power boundary / Total voltage) = MIN(280 * 18 * 0.2, 387 / 832.8 * 1000) = MIN(1008, 465) = 465A.

[0062] Update trigger SOC = 94.9%.

[0063] State 2: After the test system discharges reversely for a certain period of time, the system state is: SOC = 92.4%, Maximum monomer voltage = 3.448V, Total voltage = 827.5V. Since the SOC drop (94.9% - 92.4% = 2.5%) does not reach the cancellation threshold (5%), the charging echelon power boundary remains 387kW, and the charging echelon current boundary remains 465A.

[0064] State 3: After the test system continues to discharge in reverse for a certain period of time, the system state is: SOC = 87.4%, maximum cell voltage = 3.434V, total voltage = 824.1V. The SOC drop (94.9% - 87.4% = 7.5%) reaches the cancellation threshold (5%), then the charging power / current boundary is calculated at the normal rate as follows:

[0065] Charging ladder power boundary = (charging power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935kW.

[0066] Charging ladder current boundary = MIN(rated capacity * number of closed clusters * system rate, charging ladder power boundary / total voltage) = MIN(280 * 18 * 0.5, 1935 / 824.1 * 1000) = MIN(2520, 2348) = 2348A.

[0067] The cancellation threshold is preferably 3% - 5%, which can limit the oscillation of the power boundary and can promptly restore the normal charge and discharge state and power boundary when exiting the charge and discharge limit interval.

[0068] Example B

[0069] State 1: A certain charging state of the test system is: SOC = 57.5%, maximum cell voltage = 3.378V, total voltage = 809.9V. The maximum cell voltage does not fall within the limit interval [3.45, 3.5), then the charging power / current boundary is calculated at the normal rate as follows:

[0070] Charging ladder power boundary = (charging power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935kW.

[0071] Charging ladder current boundary = MIN(rated capacity * number of closed clusters * system rate, charging ladder power boundary / total voltage) = MIN(280 * 18 * 0.5, 1935 / 809.9 * 1000) = MIN(2520, 2389) = 2389A.

[0072] As Figure 3 shown, the calculation process of the discharging ladder power boundary includes the following steps:

[0073] The main task will regularly call the discharging end ladder boundary calculation process, and based on the current battery state, determine and calculate the latest ladder power boundary for subsequent determination and calculation.

[0074] (1) When the energy storage battery is in the discharge state, determine whether the minimum value of the single-cell voltage falls within the charging end limit interval; when the minimum value of the single-cell voltage does not fall within the discharge end limit interval, execute the normal strategy, calculate the discharge end power boundary and the discharge end current boundary according to the normal strategy, and update the discharge end normal calculation flag; when the maximum value of the single-cell voltage falls within the discharge end limit interval, execute the limit strategy, calculate the discharge end power boundary and the discharge end current boundary according to the limit strategy, and update the discharge end limit calculation flag.

[0075] (2) In the discharge limit trigger state, detect the SOC and determine whether the SOC meets the discharge boundary recovery requirement; when the SOC meets the discharge boundary recovery requirement, restore the discharge end power boundary and the discharge end current boundary according to the normal strategy, and update the discharge end recovery calculation flag.

[0076] In the above steps, the formula for calculating the discharge cycle power / current boundary under the normal strategy is:

[0077] Discharge cycle power boundary = (discharge power limit / number of configured clusters) * number of closed clusters;

[0078] Discharge cycle current boundary = MIN (rated capacity * number of closed clusters, discharge cycle power boundary / total voltage).

[0079] The formula for calculating the discharge cycle power / current boundary under the limit strategy is:

[0080] Discharge cycle power boundary = (discharge power limit / number of configured clusters) * number of closed clusters * power limit factor;

[0081] Discharge cycle current boundary = MIN (rated capacity * number of closed clusters * current limit factor, discharge cycle power boundary / total voltage).

[0082] The following gives a calculation example:

[0083] Assume that the number of closed clusters in the test system is 18 clusters, and the discharge end limit interval is configured as follows: voltage range: [2.9, 2.95); power limit factor: 0.4; current limit factor: 0.4; SOC increase for canceling the limit: 5%.

[0084] Example C

[0085] State 1: A certain discharge state of the test system is: SOC = 3.7%, minimum value of single-cell voltage = 2.944V, total voltage = 706.8V. The minimum value of the single-cell voltage falls within the limit interval [2.9, 2.95), then calculate the discharge power / current boundary according to the limit interval as follows:

[0086] Discharge elevator power boundary = (discharge power limit / number of configured clusters) * number of closed clusters * power limit factor = (2150 / 20) * 18 * 0.4 = 774 kW;

[0087] Discharge elevator current boundary = MIN(rated capacity * number of closed clusters * current limit factor, discharge elevator power boundary / total voltage) = MIN(280 * 18 * 0.4, 774 / 706.8 * 1000) = MIN(2016, 1095) = 1095 A.

[0088] Update trigger SOC = 3.7%.

[0089] State 2: After the test system reversely charges for a certain period of time, the system state is: SOC = 5.1%, minimum cell voltage = 3.044 V, total voltage = 730.6 V. Since the SOC increase (5.1% - 3.7% = 1.4%) does not reach the cancellation threshold (5%), the discharge elevator power boundary remains 774 kW, and the discharge elevator current boundary remains 1095 A.

[0090] State 3: After the test system continues to reversely charge for a certain period of time, the system state is: SOC = 9.1%, minimum cell voltage = 3.123 V, total voltage = 748.1 V. The SOC increase (9.1% - 3.7% = 5.4%) reaches the cancellation threshold (5%), then calculate the discharge power / current boundary according to the normal rate as follows:

[0091] Discharge elevator power boundary = (discharge power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935 kW;

[0092] Discharge elevator current boundary = MIN(rated capacity * number of closed clusters * system rate, discharge elevator power boundary / total voltage) = MIN(280 * 18 * 0.5, 1935 / 748.1 * 1000) = MIN(2520, 2587) = 2587 A.

[0093] Example D

[0094] State 1: In a certain discharge state of the test system: SOC = 78.6%, minimum cell voltage = 3.329 V, total voltage = 799.7 V. The minimum cell voltage does not fall within the restricted range [2.9, 2.95), then calculate the discharge power / current boundary according to the normal rate as follows:

[0095] Discharge elevator power boundary = (discharge power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935 kW;

[0096] Discharge elevator secondary current boundary = MIN(Rated capacity * Number of closing clusters * System multiple, Discharge elevator secondary power boundary / Total voltage) = MIN(280 * 18 * 0.5, 1935 / 799.7 * 1000) = MIN(2520, 2420) = 2420A.

[0097] 2. Calculation of SOP power boundary

[0098] As Figure 4 shown, the main task will regularly call the charging SOP power boundary calculation process to calculate the charging SOP power boundary according to the latest status for subsequent logic determination and calculation of the comprehensive power boundary. Specifically, it includes:

[0099] Obtain the charging SOP data table according to the cell specifications;

[0100] Check abnormal states such as system closing, protection / fault triggering, overvoltage alarm triggering, overcharge alarm triggering, etc. and handle them;

[0101] Detect the extreme temperature of the energy storage battery, where the extreme temperature includes the maximum cell temperature and the minimum cell temperature. When the minimum cell temperature in the energy storage battery is lower than the minimum operating temperature, or the maximum cell temperature is higher than the maximum operating temperature, it means that the extreme temperature of the energy storage battery exceeds the operating range of the charging SOP, and the charging SOP limit factor = 0; otherwise, find the corresponding SOP limit factors: Rate_tmin and Rate_tmax according to SOC and the extreme temperature; calculate the actual charging SOP limit factor = MIN(Rate_tmin, Rate_tmax);

[0102] Calculate the charging SOP power boundary:

[0103] Charging SOP power boundary = Cluster nominal power * Number of closing clusters * Actual charging SOP limit factor;

[0104] Charging SOP current boundary = MIN(Rated capacity * Number of closing clusters * Actual charging SOP limit factor, Charging SOP power boundary / Total voltage);

[0105] Cluster nominal power = Nominal voltage * Number of cells * Rated capacity.

[0106] Rate_tmin represents the SOP limit factor obtained by querying the charging SOP data table based on SOC and the maximum cell temperature, Rate_tmax represents the SOP limit factor obtained by querying the charging SOP data table based on SOC and the maximum cell temperature, and MIN represents taking the minimum value.

[0107] The minimum operating temperature and the maximum operating temperature correspond to the temperature lower limit (0°C) and upper limit (62°C) of the charging SOP data table, as Figure 5 shown.

[0108] Similarly, as Figure 6 shown, the main task will regularly call the discharge SOP power boundary calculation process to calculate the charging SOP power boundary according to the latest status for subsequent logical determination and calculation of the comprehensive power boundary. Specifically, it includes:

[0109] Obtain the discharge SOP data table according to the cell specifications;

[0110] Check abnormal states such as system closing, protection / fault triggering, overvoltage alarm triggering, overcharge alarm triggering, etc. and handle them;

[0111] Detect the extreme temperature of the energy storage battery, that is, the maximum and minimum cell temperatures in the energy storage battery. When the minimum cell temperature in the energy storage battery is lower than the minimum operating temperature, or the maximum cell temperature is higher than the maximum operating temperature, it means that the extreme temperature of the energy storage battery exceeds the operating range of the discharge SOP, and the discharge SOP limit factor = 0; otherwise, find the corresponding SOP limit factors: Rate_tmin and Rate_tmax according to the SOC and extreme temperature; calculate the actual discharge SOP limit factor = MIN(Rate_tmin, Rate_tmax);

[0112] Calculate the discharge SOP power boundary:

[0113] Discharge SOP power boundary = cluster nominal power * number of closed clusters * actual discharge SOP limit factor;

[0114] Discharge SOP current boundary = MIN(rated capacity * number of closed clusters * actual discharge SOP limit factor, discharge SOP power boundary / total voltage).

[0115] At this time, Rate_tmin represents the SOP limit factor obtained by querying the discharge SOP data table based on the SOC and the maximum cell temperature, Rate_tmax represents the SOP limit factor obtained by querying the discharge SOP data table based on the SOC and the maximum cell temperature, and MIN represents taking the minimum value.

[0116] The minimum operating temperature and the maximum operating temperature correspond to the temperature lower limit (-20°C) and upper limit (62°C) of the discharge SOP data table, as Figure 7 shown.

[0117] 3. Comprehensive power boundary calculation

[0118] As Figure 8 shown, the main task will regularly call the comprehensive power boundary calculation process to determine and calculate the final comprehensive power / current boundary and provide it to the EMS / PCS for power scheduling. Specifically, it includes:

[0119] (1) Calculation of the comprehensive charging power boundary:

[0120] Compare the actual charging SOP limit factor with the system multiple; when the actual charging SOP limit factor is less than the system multiple, considering system safety and avoiding overcharging, the comprehensive charging power boundary takes the minimum value of the charging ladder power and the charging SOP power; the comprehensive charging current boundary takes the minimum value of the charging power current boundary and the charging SOP current boundary.

[0121] When the actual charging SOP limit factor is greater than the system multiple, considering system performance and charging to the maximum extent possible, the comprehensive charging power boundary takes the maximum value of the charging ladder power and the charging SOP power; the comprehensive charging current boundary takes the maximum value of the charging power current boundary and the charging SOP current boundary.

[0122] (2) Calculation of the comprehensive discharging power boundary, which is similar to the comprehensive charging power boundary:

[0123] Compare the actual discharging SOP limit factor with the system multiple; when the actual discharging SOP limit factor is less than the system multiple, considering system safety and avoiding over-discharging, the comprehensive discharging power boundary takes the minimum value of the discharging ladder power and the discharging SOP power; the comprehensive discharging current boundary takes the minimum value of the discharging power current boundary and the discharging SOP current boundary.

[0124] When the actual discharging SOP limit factor is greater than the system multiple, considering system performance and discharging to the maximum extent possible, the comprehensive discharging power boundary takes the maximum value of the discharging ladder power and the discharging SOP power; the comprehensive discharging current boundary takes the maximum value of the discharging power current boundary and the discharging SOP current boundary.

[0125] Figure 8 In it, MAX() is the maximum value function.

[0126] Figure 9 It is the power boundary relationship curve during the discharging process when the number of closing clusters is 18 and the discharging ladder limit factor is 0.4. The description is as follows:

[0127] The X-axis is the time axis, and the test process from T1 to T9 is as follows:

[0128] (T1) Normal charging, battery status: total voltage = 824V, SOC = 93.2%, maximum value of single-cell temperature = 21, minimum value of single-cell temperature = 17, maximum value of single-cell voltage = 3.432, minimum value of single-cell voltage = 3.402.

[0129] The actual charging SOP limit factor = MIN(0.35, 0.35) = 0.35.

[0130] Charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.35 = 1355 kW.

[0131] Charging echelon power boundary = (charging power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935 kW.

[0132] The actual charging SOP limit factor (0.35) is less than the system multiple (0.5), so the charging comprehensive power boundary = MIN(charging SOP power boundary, charging echelon power boundary) = MIN(1355, 1935) = 1355 kW.

[0133] (T2) Normal charging, battery status: total voltage = 826 V, SOC = 93.8%, maximum monomer temperature = 23, minimum monomer temperature = 21, maximum monomer voltage = 3.441, minimum monomer voltage = 3.421.

[0134] Actual charging SOP limit factor = MIN(0.35, 0.5) = 0.35.

[0135] Charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.35 = 1355 kW.

[0136] Charging echelon power boundary = (charging power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935 kW.

[0137] The actual charging SOP limit factor (0.35) is less than the system multiple (0.5), so the charging comprehensive power boundary = MIN(charging SOP power boundary, charging echelon power boundary) = MIN(1355, 1935) = 1355 kW.

[0138] (T3) Charging limit triggered, battery status: total voltage = 833 V, SOC = 94.9%, maximum monomer temperature = 24, minimum monomer temperature = 21, maximum monomer voltage = 3.47, minimum monomer voltage = 3.451.

[0139] Actual charging SOP limit factor = MIN(0.35, 0.5) = 0.35.

[0140] Charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.35 = 1355 kW.

[0141] Charging echelon power boundary = (charging power limit / number of configured clusters) * number of closed clusters * power limit factor = (2150 / 20) * 18 * 0.2 = 387kW.

[0142] The actual charging SOP limit factor (0.35) is less than the system multiple (0.5), so the charging comprehensive power boundary = MIN(charging SOP power boundary, charging echelon power boundary) = MIN(1355, 387) = 387kW.

[0143] The SOC at the time of recording trigger = 94.9%.

[0144] (T4) Reverse discharge but the limit release condition is not met. Battery status: total voltage = 828V, SOC = 92.4%, maximum monomer temperature = 25, minimum monomer temperature = 21, maximum monomer voltage = 3.448, minimum monomer voltage = 3.441.

[0145] The actual charging SOP limit factor = MIN(0.35, 0.5) = 0.35.

[0146] Charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.35 = 1355kW.

[0147] Since the charging limit release condition is not met (94.9% - 92.4% = 2.5% < 5%), the charging echelon power boundary remains the previous limit value of 387kW.

[0148] The actual charging SOP limit factor (0.35) is less than the system multiple (0.5), so the charging comprehensive power boundary = MIN(charging SOP power boundary, charging echelon power boundary) = MIN(1355, 387) = 387kW.

[0149] (T5) Reverse discharge has met the limit release condition. Battery status: total voltage = 824V, SOC = 87.4%, maximum monomer temperature = 26, minimum monomer temperature = 23, maximum monomer voltage = 3.434, minimum monomer voltage = 3.430.

[0150] The actual charging SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0151] Charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.5 = 1935kW.

[0152] Since the charging limit release condition is satisfied (94.9% - 87.4% = 7.5% > 5%), the charging echelon power boundary = (charging power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935 kW.

[0153] The actual charging SOP limit factor (0.5) is equal to the system multiple (0.5), so the charging comprehensive power boundary = MAX(charging SOP power boundary, charging echelon power boundary) = MAX(1935, 1935) = 1935 kW.

[0154] (T6) Normal charging, battery status: total voltage = 823 V, SOC = 91.8%, maximum cell temperature = 27, minimum cell temperature = 25, maximum cell voltage = 3.429, minimum cell voltage = 3.402.

[0155] The actual charging SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0156] The charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0157] The charging echelon power boundary = (charging power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935 kW.

[0158] The actual charging SOP limit factor (0.5) is equal to the system multiple (0.5), so the charging comprehensive power boundary = MAX(charging SOP power boundary, charging echelon power boundary) = MAX(1935, 1935) = 1935 kW.

[0159] (T7) Charging limit triggered, battery status: total voltage = 832 V, SOC = 93.9%, maximum cell temperature = 28, minimum cell temperature = 22, maximum cell voltage = 3.465, minimum cell voltage = 3.451.

[0160] The actual charging SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0161] The charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0162] The charging echelon power boundary = (charging power limit / number of configured clusters) * number of closed clusters * power limit factor = (2150 / 20) * 18 * 0.2 = 387 kW.

[0163] The actual charging SOP limit factor (0.5) is equal to the system rate (0.5), so the charging comprehensive power boundary = MAX(charging SOP power boundary, charging echelon power boundary) = MAX(1935, 387) = 1935 kW.

[0164] The SOC at the time of recording trigger = 93.9%.

[0165] (T8) Reverse discharging but the limit release condition is not met. Battery status: total voltage = 827 V, SOC = 91.7%, maximum cell temperature = 29, minimum cell temperature = 24, maximum cell voltage = 3.445, minimum cell voltage = 3.437.

[0166] The actual charging SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0167] The charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0168] Since the charging limit release condition is not met (93.9% - 91.7% = 2.2% < 5%), the charging echelon power boundary remains the previous limit value of 387 kW.

[0169] The actual charging SOP limit factor (0.5) is equal to the system rate (0.5), so the charging comprehensive power boundary = MAX(charging SOP power boundary, charging echelon power boundary) = MAX(1935, 387) = 1935 kW.

[0170] (T9) Reverse discharging has met the limit release condition. Battery status: total voltage = 825 V, SOC = 88.1%, maximum cell temperature = 28, minimum cell temperature = 23, maximum cell voltage = 3.439, minimum cell voltage = 3.423.

[0171] The actual charging SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0172] The charging SOP power boundary = cluster nominal power * number of closed clusters * actual charging SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0173] Since the charging limit release condition is met (93.9% - 88.1% = 5.7% > 5%), the charging echelon power boundary = (charging power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935 kW.

[0174] The actual charging SOP limit factor (0.5) is equal to the system multiple (0.5). Therefore, the charging comprehensive power boundary = MAX(charging SOP power boundary, charging echelon power boundary) = MAX(1935, 387) = 1935 kW.

[0175] Figure 10 It is the power boundary relationship curve of the discharging process when the closing cluster number is 18 and the discharging echelon limit factor is 0.4.

[0176] The description is as follows;

[0177] The X-axis is the time axis. The test process from T1 to T5 is as follows:

[0178] (T1) Normal discharging. Battery status: Total voltage = 765 V, SOC = 10.2%, maximum monomer temperature = 21, minimum monomer temperature = 17, maximum monomer voltage = 3.187, minimum monomer voltage = 3.178.

[0179] The actual discharging SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0180] The discharging SOP power boundary = cluster nominal power * closing cluster number * actual discharging SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0181] The discharging echelon power boundary = (discharging power limit / configured cluster number) * closing cluster number = (2150 / 20) * 18 = 1935 kW.

[0182] The actual discharging SOP limit factor (0.5) is equal to the system multiple (0.5). Therefore, the discharging comprehensive power boundary = MAX(discharging SOP power boundary, discharging echelon power boundary) = MAX(1935, 1935) = 1935 kW.

[0183] (T2) Normal discharging. Battery status: Total voltage = 754 V, SOC = 9.8%, maximum monomer temperature = 23, minimum monomer temperature = 21, maximum monomer voltage = 3.142, minimum monomer voltage = 3.131.

[0184] The actual discharging SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0185] The discharging SOP power boundary = cluster nominal power * closing cluster number * actual discharging SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0186] The discharging echelon power boundary = (discharging power limit / configured cluster number) * closing cluster number = (2150 / 20) * 18 = 1935 kW.

[0187] The actual discharge SOP limit factor (0.5) is equal to the system multiple (0.5). Therefore, the discharge comprehensive power boundary = MAX(discharge SOP power boundary, discharge cycle power boundary) = MAX(1935, 1935) = 1935 kW.

[0188] (T3) Trigger the discharge limit. Battery status: Total voltage = 708 V, SOC = 3.7%, maximum monomer temperature = 24, minimum monomer temperature = 21, maximum monomer voltage = 2.951, minimum monomer voltage = 2.944.

[0189] The actual discharge SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0190] The discharge SOP power boundary = cluster nominal power * number of closed clusters * actual discharge SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0191] The discharge cycle power boundary = (discharge power limit / number of configured clusters) * number of closed clusters * power limit factor = (2150 / 20) * 18 * 0.4 = 774 kW.

[0192] The actual discharge SOP limit factor (0.5) is equal to the system multiple (0.5). Therefore, the discharge comprehensive power boundary = MAX(discharge SOP power boundary, discharge cycle power boundary) = MAX(1935, 774) = 1935 kW.

[0193] Record that the SOC is 3.7% when the limit is triggered.

[0194] (T4) Reverse charging but the limit release condition is not met. Battery status: Total voltage = 736 V, SOC = 5.1%, maximum monomer temperature = 25, minimum monomer temperature = 21, maximum monomer voltage = 3.068, minimum monomer voltage = 3.044.

[0195] The actual discharge SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0196] The discharge SOP power boundary = cluster nominal power * number of closed clusters * actual discharge SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0197] Since the discharge limit release condition is not met (5.1% - 3.7% = 1.4% < 5%), the discharge cycle power boundary remains the previous limit value of 774 kW.

[0198] The actual discharge SOP limit factor (0.5) is equal to the system multiple (0.5). Therefore, the combined discharge power boundary = MAX(discharge SOP power boundary, discharge cycle power boundary) = MAX(1935, 774) = 1935 kW.

[0199] (T5) Reverse charging has met the limit release condition. Battery status: total voltage = 754 V, SOC = 9.1%, maximum cell temperature = 26, minimum cell temperature = 23, maximum cell voltage = 3.141, minimum cell voltage = 3.123.

[0200] The actual discharge SOP limit factor = MIN(0.5, 0.5) = 0.5.

[0201] The discharge SOP power boundary = cluster nominal power * number of closed clusters * actual discharge SOP limit factor = 215.04 * 18 * 0.5 = 1935 kW.

[0202] Since the discharge limit release condition has been met (9.1% - 3.7% = 5.4% > 5%), the discharge cycle power boundary = (discharge power limit / number of configured clusters) * number of closed clusters = (2150 / 20) * 18 = 1935 kW.

[0203] The actual discharge SOP limit factor (0.5) is equal to the system multiple (0.5). Therefore, the combined discharge power boundary = MAX(discharge SOP power boundary, discharge cycle power boundary) = MAX(1935, 1935) = 1935 kW.

[0204] Figure 11 It is the voltage, current, and power relationship curve of the charging process under the condition that the number of closed clusters is 18 and the charging cycle limit factor is 0.2. Figure 12 It is the voltage, current, and power relationship curve of the discharge process under the condition that the number of closed clusters is 18 and the discharge cycle limit factor is 0.4. Among them, the charging current / power is represented by a negative value, and the discharge current / power is represented by a positive value.

[0205] In summary, the battery power control method of the present invention can achieve the following technical effects:

[0206] 1. Through the end-of-charge / discharge cycle limit, at the end of charge and discharge, according to the system operating conditions, the charge and discharge power boundaries can be made to decrease in steps. In this way, the power boundary can be adjusted more precisely, enabling the energy storage battery to be discharged and charged to the fullest, and avoiding triggering overvoltage / undervoltage alarms / protections, maximizing the performance of the energy storage battery, and achieving the efficient utilization and long-life operation of the energy storage battery.

[0207] 2. Based on the SOP look-up table limit, taking into account the specifications and operating parameters of energy storage batteries, such as factors like internal resistance, thermal effect, voltage drop, etc., to better manage the differences in energy storage batteries of different manufacturers and specifications, and improve the compatibility of the energy storage system.

[0208] 3. Introducing feedback and correction links can real-time correct the charge and discharge power boundaries and avoid overcharging and over-discharging of energy storage batteries.

[0209] Although the present invention has been specifically shown and described in conjunction with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present invention in terms of form and details without departing from the spirit and scope of the present invention defined by the appended claims, and all such changes are within the protection scope of the present invention.

Claims

1. A battery power control method based on voltage and SOP limitation, characterized in that, include: Status data collection steps: collect the current status data of the energy storage battery, including single cell voltage, single cell temperature, bus voltage, and bus current; Data processing steps: remove outliers, estimate SOC, calculate extreme values ​​of cell voltage and cell temperature, and determine abnormal conditions; Steps for calculating the step power boundary: detecting the cell voltage, and when the cell voltage falls into the charging end or discharging end limit interval, calculating the step power boundary and triggering the charging limit or discharging limit; SOP power boundary calculation steps: Based on the SOP data table of the energy storage battery and combined with the current state data of the energy storage battery, calculate the SOP power boundary of charging and discharging; Comprehensive power boundary calculation steps: When the charge limit or discharge limit is triggered, the smaller of the step power boundary and the SOP power boundary of charge and discharge is taken as the comprehensive power boundary; When the charge limit or discharge limit is triggered, the smaller of the step power boundary and the SOP power boundary of charge and discharge is taken as the comprehensive power boundary; Feedback and correction steps: monitor the energy storage battery status in real time, recalculate the echelon power boundary and SOP power boundary, and update the comprehensive power boundary to EMS / PCS as the upper limit of power scheduling.

2. The method according to claim 1, characterized in that The step of calculating the step power boundary comprises: Regularly call the charging terminal echelon boundary calculation process: Obtain the state of the energy storage battery, and when the energy storage battery is in a charging state, determine whether the maximum value of the single cell voltage falls within the charging terminal limit range; When the maximum value of the single cell voltage does not fall within the charging terminal limit interval, the normal strategy is executed, the charging terminal power boundary and the charging terminal current boundary are calculated according to the normal strategy, and the charging terminal normal calculation flag is updated; When the maximum value of the single cell voltage falls within the charging terminal limit interval, the limit strategy is executed, the charging terminal power boundary and the charging terminal current boundary are calculated according to the limit strategy, and the charging terminal limit calculation flag is updated; In the charging limit triggering state, the SOC is detected to determine whether the SOC meets the charging boundary recovery requirements; When the SOC meets the charging boundary recovery requirements, the charging terminal power boundary and the charging terminal current boundary are restored according to the normal strategy, and the charging terminal recovery calculation flag is updated; When the energy storage battery is discharged, the discharge end step boundary calculation process is called regularly: Obtain the state of the energy storage battery, and when the energy storage battery is in a discharging state, determine whether the minimum value of the single cell voltage falls within the charging terminal limit range; When the minimum value of the single cell voltage does not fall within the discharge end limit interval, the normal strategy is executed, the discharge end power boundary and the discharge end current boundary are calculated according to the normal strategy, and the discharge end normal calculation flag is updated; When the maximum value of the single cell voltage falls within the discharge end limit interval, the limit strategy is executed, the discharge end power boundary and the discharge end current boundary are calculated according to the limit strategy, and the discharge end limit calculation flag is updated; In the discharge limit triggering state, the SOC is detected to determine whether the SOC meets the discharge boundary recovery requirements; When the SOC meets the discharge boundary recovery requirements, the discharge end power boundary and the discharge end current boundary are restored according to the normal strategy, and the discharge end recovery calculation flag is updated.

3. The method according to claim 2, characterized in that The formula for calculating the charging power / current boundary under the normal strategy is: Charging power limit = (charging power limit / number of configured clusters) * number of closed clusters; Charging ladder current limit = MIN (rated capacity * number of closing clusters, charging ladder power limit / total voltage); The formula for calculating the charging power / current boundary under the restriction strategy is: Charging power limit = (charging power limit / number of configured clusters) * number of switched clusters * power limit factor; Charging ladder current limit = MIN (rated capacity * number of closing clusters * current limit factor, charging ladder power limit / total voltage); The formula for calculating the power / current boundary of the elevator under the normal strategy is: Discharge power limit = (discharge power limit / number of configured clusters) * number of closed clusters; Discharge secondary current limit = MIN (rated capacity * number of closing clusters, discharge secondary power limit / total voltage); The formula for calculating the power / current boundary of the elevator under the limiting strategy is: Discharge power limit = (discharge power limit / number of configured clusters) * number of closed clusters * power limit factor; Discharge secondary current limit = MIN (rated capacity * number of closing clusters * current limiting factor, discharge secondary power limit / total voltage); Among them, MIN() is the minimum value function.

4. The method according to claim 2, characterized in that In the charging limit triggering state, the method of detecting the SOC and determining whether the SOC meets the discharge boundary recovery requirement is as follows: detecting whether the SOC reduction reaches the cancellation threshold; In the discharge limit triggering state, the method of detecting the SOC and determining whether the SOC meets the discharge boundary recovery requirement is as follows: detecting whether the SOC increase reaches the cancellation threshold; The SOC reduction is the difference between the SOC marked when the charging limit is triggered and the current SOC; The SOC increase is the difference between the current SOC and the SOC marked when the discharge limit is triggered.

5. The method according to claim 4, characterized in that The cancellation threshold is 3% to 5%.

6. The method according to claim 1, characterized in that The SOP power boundary calculation step is performed periodically, including: Call the charging SOP power boundary calculation process: obtain the charging SOP data table according to the battery cell specifications; detect the temperature extremes of the energy storage battery, which include the maximum and minimum temperatures of the single cells; when the minimum temperature of the single cell in the energy storage battery is lower than the minimum operating temperature, or the maximum temperature of the single cell is higher than the maximum operating temperature, the actual charging SOP limit factor = 0; otherwise, find the corresponding first charging SOP limit factor and second charging SOP limit factor according to the SOC and temperature extremes; use the minimum of the first charging SOP limit factor and the second charging SOP limit factor as the actual charging SOP limit factor, and calculate the charging SOP power boundary: Call the discharge SOP power boundary calculation process, and obtain the discharge SOP data table according to the battery cell specifications; detect the temperature extremes of the energy storage battery; when the minimum temperature of the single cell in the energy storage battery is lower than the minimum operating temperature, or the maximum temperature of the single cell is higher than the maximum operating temperature, the actual discharge SOP limit factor = 0; otherwise, find the corresponding first discharge SOP limit factor and second discharge SOP limit factor according to the SOC and temperature extremes; use the minimum value of the first discharge SOP limit factor and the second discharge SOP limit factor as the actual discharge SOP limit factor, and calculate the discharge SOP power boundary.

7. The method according to claim 6, characterized in that The calculation formula of the charging SOP power boundary is: Charging SOP power boundary = cluster nominal power * number of switched-on clusters * actual charging SOP limit factor; Charging SOP current limit = MIN (rated capacity * number of closing clusters * actual charging SOP limiting factor, charging SOP power limit / total voltage); The calculation formula of the discharge SOP power boundary is: Discharge SOP power boundary = cluster nominal power * number of closed clusters * actual discharge SOP limit factor; Discharge SOP current limit = MIN (rated capacity * number of closing clusters * actual discharge SOP limit factor, discharge SOP power limit / total voltage); Among them, cluster nominal power = nominal voltage * number of cells * rated capacity.

8. The method according to claim 6, characterized in that The temperature range of the charging SOP is 0°-62°; The operating temperature range of the discharge SOP is -20°-62°.

9. The method according to claim 1, characterized in that The comprehensive power boundary calculation step is performed periodically, including: Call the calculation process of charging comprehensive power boundary: compare the actual charging SOP limit factor and the system rate; when the actual charging SOP limit factor is less than the system rate, its charging comprehensive power boundary takes the minimum value of the charging ladder power and the charging SOP power; the charging comprehensive current boundary takes the minimum value of the charging power current boundary and the charging SOP current boundary; when the actual charging SOP limit factor is greater than the system rate, its charging comprehensive power boundary takes the maximum value of the charging ladder power and the charging SOP power; the charging comprehensive current boundary takes the maximum value of the charging power current boundary and the charging SOP current boundary; Call the discharge comprehensive power boundary calculation process: compare the actual discharge SOP limiting factor and the system multiple; when the actual discharge SOP limiting factor is less than the system multiple, its discharge comprehensive power boundary takes the minimum value of the elevator subpower and the discharge SOP power; the discharge comprehensive current boundary takes the minimum value of the discharge power current boundary and the discharge SOP current boundary; when the actual discharge SOP limiting factor is greater than the system multiple, its discharge comprehensive power boundary takes the maximum value of the elevator subpower and the discharge SOP power; the discharge comprehensive current boundary takes the maximum value of the discharge power current boundary and the discharge SOP current boundary.

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