A method for preventing reverse flow control of a commercial energy storage system

Abstract

The application belongs to the technical field of energy storage energy management, and relates to a reverse flow control method for a commercial and industrial energy storage system, which comprises the following steps: collecting total table power, current charging and discharging power, power setting value of the last period and reverse flow target value, and calculating power deviation; obtaining real-time power data of a disturbance source and processing the same to obtain a change trend, and generating a feedforward compensation power value according to the change trend; taking the current charging and discharging power or the power setting value of the last period as a reference, combining the power deviation and the feedforward compensation value to calculate a basic power setting value; performing asymmetric rate adjustment on the basic power setting value, adopting slow rise adjustment when the power deviation is greater than zero, and adopting rapid drop adjustment when the power deviation is less than or equal to zero, to obtain an adjusted power setting value; and finally, the power setting value is subjected to power limiting and then sent to an energy storage converter. The application responds to a disturbance in advance through feedforward compensation, avoids power crossing through asymmetric adjustment, effectively eliminates the reverse flow phenomenon, and improves the reverse flow reliability and dynamic response speed in a photovoltaic storage integration scene.

Description

Technical Field

[0001] This application relates to the field of energy storage and energy management technology, and in particular to a method for preventing backflow control in industrial and commercial energy storage systems. Background Technology

[0002] Commercial and industrial energy storage systems refer to power systems installed on the industrial or commercial user side, which use energy storage converters to control the charging and discharging of batteries to achieve functions such as peak shaving and valley filling, demand management, and emergency backup power. In grid-connected operation, backflow prevention refers to controlling the charging and discharging power of the energy storage system to prevent power at the grid connection point (i.e., the connection point between the user and the grid) from flowing back to the grid, or to keep it below a set reverse power threshold, thereby avoiding impact on the grid and preventing backflow.

[0003] Currently, commonly used anti-reverse current control methods mainly include three categories: First, threshold comparison combined with constant power control, which directly shuts down or limits power when the grid connection point power is lower than the set value. This method has a coarse response and is prone to sudden power changes. Second, proportional-integral-derivative closed-loop regulation, which tracks the anti-reverse current target through feedback control, but the response is lagging when the load or photovoltaic power fluctuates drastically, and temporary reverse current will still occur. Third, simple droop control, which adjusts the power according to the grid connection point frequency or voltage, has limited control effect under strong grid conditions.

[0004] In photovoltaic-storage coupled systems, when the energy storage battery is fully charged and charging suddenly stops, the photovoltaic power cannot be absorbed in time, easily triggering reverse current. More critically, the existing methods mentioned above are all pure feedback control, which can only act when reverse current occurs or is about to occur. They lack the ability to proactively adjust for sudden load changes or surges in photovoltaic power, making it difficult to achieve coordinated photovoltaic-storage control. This results in slow anti-reverse current response and insufficient disturbance rejection capability. Therefore, there is an urgent need for an anti-reverse current control method that can respond faster, predict in advance, and proactively adjust. Summary of the Invention

[0005] The purpose of this application is to propose an anti-backflow control method for industrial and commercial energy storage systems, in order to solve the response lag defect caused by the pure feedback mechanism in existing anti-backflow control methods. It provides an anti-backflow control method that can perform feedforward compensation in advance according to the trend of disturbance change, and takes into account the synergy between photovoltaic and energy storage, so as to achieve a fast, accurate and backflow-free control effect.

[0006] To address the aforementioned technical problems, this application provides an anti-backflow control method for industrial and commercial energy storage systems, employing the following technical solution: Collect the total power of the energy storage system, the current charging and discharging power, the power setpoint of the previous cycle, and the anti-reverse current target power value; Calculate the power deviation between the total power meter reading and the anti-backflow target power value; Acquire real-time power data of the disturbance source, process the real-time power data to obtain the power change trend of the disturbance source, and generate a feedforward compensation power value based on the power change trend; Based on the current charging / discharging power or the power setting value of the previous cycle, combined with the power deviation and the feedforward compensation power value, the base power setting value is calculated. The basic power setting value is adjusted at an asymmetric rate. When the power deviation is greater than zero, a gradual increase adjustment method is used, and when the power deviation is less than or equal to zero, a rapid decrease adjustment method is used to obtain the adjusted power setting value. The adjusted power setting value is limited according to the upper and lower limits of the energy storage system power to obtain the final power command, which is then sent to the energy storage converter for execution.

[0007] Furthermore, the step of generating the feedforward compensation power value includes: Calculate the difference between the total power at the current time and the previous time. When the absolute value of the difference is greater than a preset first threshold, a feedforward compensation power value is generated based on the magnitude of the difference, and the feedforward compensation power value is positively correlated with the magnitude of the difference and the total response delay time of the energy storage system. When the absolute value of the difference is less than or equal to the first threshold, the feedforward compensation power value is set to zero.

[0008] Furthermore, the disturbance source is a photovoltaic power generation system, and the step of generating the feedforward compensation power value includes: Obtain the photovoltaic power and calculate the difference between the photovoltaic power at the current time and the photovoltaic power at the previous time. When the absolute value of the photovoltaic power difference is greater than a preset second threshold, a feedforward compensation power value is generated based on the magnitude of the photovoltaic power difference. The feedforward compensation power value is positively correlated with the magnitude of the photovoltaic power difference and the total response delay time of the energy storage system, and the sign of the feedforward compensation power value is opposite to the sign of the photovoltaic power difference. When the absolute value of the photovoltaic power difference is less than or equal to the second threshold, the feedforward compensation power value is set to zero.

[0009] Furthermore, the disturbance source is a load system, and the step of generating the feedforward compensation power value includes: Obtain the load power and calculate the difference between the load power at the current time and the load power at the previous time. When the absolute value of the load power difference is greater than a preset third threshold, a feedforward compensation power value is generated based on the magnitude of the load power difference. The feedforward compensation power value is positively correlated with the magnitude of the load power difference and the total response delay time of the energy storage system, and the sign of the feedforward compensation power value is opposite to the sign of the load power difference. When the absolute value of the load power difference is less than or equal to the third threshold, the feedforward compensation power value is set to zero.

[0010] Furthermore, the gradual increase adjustment method specifically includes: When the absolute value of the power deviation is less than or equal to the first adjustment threshold, the power deviation is compared with the preset maximum single adjustment step size, and the smaller of the two values ​​is taken as the adjustment amount for this time. When the absolute value of the power deviation is greater than the first adjustment threshold and less than or equal to the second adjustment threshold, half of the power deviation is used as the adjustment amount for this adjustment, but not exceeding the preset maximum single adjustment step size. When the absolute value of the power deviation is greater than the second adjustment threshold, the preset fast adjustment threshold is adjusted once, and then the difference between the power deviation and the fast adjustment threshold is processed according to the adjustment method when the absolute value of the power deviation is less than or equal to the first adjustment threshold.

[0011] Furthermore, for energy storage systems connected to photovoltaic power generation systems, a step of limiting charging power in advance is also included: Obtain the state of charge (SOC) of the energy storage battery and set the upper limit of SOC and the loopback width; When the state of charge is greater than or equal to the upper limit of the state of charge, the charging power limit is set to zero; When the state of charge is within the range of the upper limit of the state of charge minus the loopback width to the upper limit of the state of charge, the charging power limit value is gradually reduced according to the ratio of the difference between the state of charge and the upper limit of the state of charge to the loopback width. The adjusted power setting value is compared with the charging power limit value, and the larger value is taken as the final power command.

[0012] Furthermore, it also includes exception handling steps: When the data sampling of the total power meter fails or communication is interrupted, the power command of the previous cycle is retained; When the duration of the failure to sample the total power data or the communication interruption exceeds a preset time threshold, the energy storage system will be switched to a preset standby power mode.

[0013] Furthermore, the total response delay of the energy storage system includes the sum of data sampling delay, communication transmission delay, and energy storage converter execution delay, which is obtained through pre-testing.

[0014] Furthermore, the rapid reduction adjustment method is as follows: the power deviation is used as the adjustment amount for this adjustment and directly added to the basic power setting value.

[0015] Furthermore, the maximum single adjustment step size in the gradual increase adjustment method is adjusted according to the fluctuation of the power deviation: When the power deviation remains the same sign for multiple consecutive control cycles, the maximum single adjustment step size is gradually increased. When the sign of the power deviation changes, the maximum single adjustment step size is restored to its initial value.

[0016] Compared with the prior art, this application has the following main advantages: This application discloses an anti-backflow control method for commercial and industrial energy storage systems. It achieves feedback regulation by collecting the deviation between the total meter power and the anti-backflow target value, and generates a feedforward compensation power value by acquiring the power change trend of the disturbance source. This allows for advance adjustment of the energy storage power during load or photovoltaic (PV) surges, significantly shortening or eliminating the duration of backflow. By employing an asymmetric rate regulation method—gradually increasing when the power deviation is greater than zero and rapidly decreasing when it is less than or equal to zero—the total meter power is stabilized slightly above the anti-backflow target value without exceeding the lower limit, preventing backflow caused by load fluctuations. For PV-storage integrated scenarios, the charging power limit is gradually reduced through SOC grading, reserving response time for the PV inverter when the energy storage is near full charge to prevent PV power backflow during charging interruptions. Simultaneously, by adaptively adjusting the gradual increase step size based on power deviation fluctuations, the system accelerates response during continuous unidirectional fluctuations and maintains stability during frequent sign changes, further improving the system's dynamic performance and robustness. This achieves efficient, reliable, and backflow-free anti-backflow control for commercial and industrial energy storage systems (especially PV-storage integrated systems). Attached Figure Description

[0017] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a flowchart of an embodiment of an anti-backflow control method for an industrial and commercial energy storage system according to this application; Detailed Implementation Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0019] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0021] refer to Figure 1 The diagram illustrates a flowchart of an embodiment of an anti-backflow control method for an industrial and commercial energy storage system according to this application. The anti-backflow control method for the industrial and commercial energy storage system includes the following steps: Step S1: Collect the total meter power, current charging and discharging power, power setting value of the previous cycle, and anti-reverse current target power value of the energy storage system.

[0022] At the beginning of each control cycle, four basic physical quantities necessary for subsequent control calculations are obtained from different data sources of the energy storage system. These four quantities are: the real-time power at the grid connection point (i.e., the main meter), the actual charging and discharging power output of the energy storage converter at the current moment, the power command value issued and executed in the previous control cycle, and the anti-reverse current target power value preset by the system.

[0023] In this embodiment, the total power is read in real time by a bidirectional energy meter installed at the connection point between the user and the grid. This energy meter measures both the magnitude and direction of power, defining a positive value (indicating power purchase from the grid) when power flows from the grid to the user and a negative value (indicating power supply to the grid, i.e., reverse flow) when power flows from the user to the grid. The current charging and discharging power of the energy storage is obtained through the internal measurement unit of the energy storage converter or its connected communication interface; the value is positive during discharging and negative during charging. The power setpoint of the previous cycle is read directly from the energy management system's memory, recording the instructions sent to the energy storage converter and successfully executed in the previous control cycle. The anti-reverse flow target power value is a constant pre-stored in the system, typically set according to the grid access agreement or owner requirements, with typical values ​​of 0 kW (no reverse flow allowed) or -5 kW (a small amount of reverse flow allowed). All data is read at a frequency consistent with the control cycle, for example, once every 2 seconds.

[0024] For example, consider a commercial or industrial energy storage system with a rated charging / discharging power of 500 kW, whose control cycle is set to 2 seconds. At the beginning of a certain control cycle, the system reads a total power of 150 kW from the grid-connected energy meter, meaning that the user side is currently absorbing 150 kW of active power from the grid. The system reads a current charging / discharging power of 100 kW from the communication interface of the energy storage converter, indicating that the energy storage is discharging at a power of 100 kW. The power setting value of 100 kW issued in the previous cycle is read from memory, which matches the current actual value, indicating that the system has stably tracked the instructions of the previous cycle. At the same time, the anti-reverse flow target power value is read from the parameter storage area as 0 kW, meaning that no reverse power flow to the grid is allowed.

[0025] Step S2: Calculate the power deviation between the total power and the anti-backflow target power value.

[0026] Subtract the total power measured in step one from the preset anti-reverse current target power value to obtain a difference. This difference is called the power deviation, which quantifies the degree of deviation between the actual power state of the current grid connection point and the expected anti-reverse current target, and serves as the basis for all subsequent adjustment calculations.

[0027] In this embodiment, the power deviation is calculated by subtracting the anti-reverse current target power value from the total meter power value. This deviation can be positive, zero, or negative. When the deviation is positive, it indicates that the actual total meter power is higher than the target value, suggesting that the current grid inflow power is too large or that reverse current has not yet occurred. The energy storage system needs to increase discharge or reduce charging to lower the total meter power. When the deviation is negative, it indicates that the actual total meter power is lower than the target value, suggesting that reverse current has occurred or is about to occur. The energy storage system needs to reduce discharge or increase charging to increase the total meter power. The absolute value of the deviation reflects the severity of the deviation; the larger the absolute value, the greater the deviation, and the larger the required adjustment range. This deviation value is recalculated based on the latest collected data in each control cycle.

[0028] For example, using the sample data from step S1, the total meter power is 150 kW, and the anti-reverse current target power value is 0 kW. Subtracting 0 from 150 gives a power deviation of 150 kW, which is positive. This means that the actual power at the current grid connection point is 150 kW higher than the target value, i.e., the power absorbed from the grid is too large, and the total meter power must be reduced by increasing discharge (or reducing charging) through energy storage. If at some later time the total meter power becomes negative 30 kW, then the power deviation is negative 30 minus 0 equals negative 30 kW, indicating that a 30 kW reverse current has occurred, and energy storage needs to immediately reduce discharge or increase charging to eliminate the reverse current.

[0029] The sign of this deviation directly indicates the direction of adjustment (increasing discharge or increasing charging), and its absolute value directly reflects the urgency of the adjustment. Compared to directly comparing the original power value, deviation calculation eliminates the differences caused by different target value settings, giving the control algorithm a unified benchmark. Simultaneously, this deviation value gradually changes over time; when the total power meter approaches the target value, the deviation approaches zero, and the system naturally stabilizes, achieving a zero steady-state error adjustment effect.

[0030] Step S3: Obtain real-time power data of the disturbance source, process the real-time power data to obtain the power change trend of the disturbance source, and generate a feedforward compensation power value based on the power change trend.

[0031] The system acquires real-time power data reflecting external disturbances. This data is analyzed to determine whether the disturbance is intensifying or weakening, and whether the rate of change is fast or slow. Based on this trend, a compensation power value is pre-calculated. This compensation value adjusts the energy storage output in advance, before the disturbance significantly affects the total meter power, thereby offsetting the impact of the impending disturbance.

[0032] In this embodiment, one or more disturbance sources are selected from the system, and their real-time power data is collected. Disturbance sources refer to external factors whose power changes directly affect the total power meter reading, such as the total power at the grid connection point itself, the output power of the photovoltaic power generation system, or the total power of the user load. The system selects available disturbance sources based on the actual on-site configuration. After collecting the real-time power data, it is compared with the data from the previous moment, and the difference between the two is calculated. The sign of this difference reflects whether the power is increasing or decreasing, and the magnitude of the difference reflects the degree of change; both together constitute the power change trend. Then, this difference is compared with a preset threshold. If the absolute value of the difference is less than or equal to the threshold, it indicates that the disturbance is not significant, and no feedforward compensation is generated; that is, the feedforward compensation power value is set to zero. If the absolute value of the difference is greater than the threshold, it indicates that there is a significant disturbance, and a feedforward compensation power value is generated proportionally based on the magnitude of the difference. The magnitude of the compensation value is positively correlated with the magnitude of the power difference, meaning the greater the disturbance, the stronger the compensation. Simultaneously, the sign of the compensation value is opposite to that of the power difference; that is, as the disturbance power increases, the compensation value points in the direction of reducing energy storage discharge or increasing energy storage charging to counteract the effect of the disturbance. Furthermore, the magnitude of the compensation value is also positively correlated with the total response delay time from sampling to execution; the greater the delay, the stronger the compensation to compensate for the impact of lag.

[0033] For example, let's consider the total power at the grid connection point as the disturbance source. Assume the system control cycle is 2 seconds. The total power measured at the previous moment was 120 kW, and the current moment's measured total power is 150 kW, a difference of 30 kW. The preset disturbance threshold is 5 kW; 30 kW is greater than 5 kW, therefore a significant disturbance is identified. The total system response delay is 0.15 seconds, and the feedforward coefficient is 0.8. Based on the trend, the power is increasing rapidly, which will push the total power further away from the anti-reverse current target value. To counteract this trend, a positive feedforward compensation power value is generated, calculated as 0.8 multiplied by 30 kW and then multiplied by 0.15 seconds, resulting in 3.6 kW. This positive value means that energy storage discharge needs to be increased or energy storage charging reduced to absorb the upcoming disturbance in advance. If the photovoltaic power collected suddenly increases from 50 kW to 80 kW, the difference is an increase of 30 kW, and the generated compensation value is negative, indicating that energy storage charging is needed to absorb the excess photovoltaic power and prevent reverse current.

[0034] Feedforward compensation adjusts in advance based on the changing trend of the disturbance source, starting before the disturbance fully affects the total power meter reading, significantly shortening the response time and fundamentally reducing the probability and duration of backflow. Simultaneously, feedforward compensation complements feedback control in subsequent steps; feedback eliminates residual errors, while feedforward counteracts known disturbances in advance. Together, they keep the total power meter reading more stably near the anti-backflow target value, avoiding large fluctuations and overshoot.

[0035] Step S4: Calculate the base power setting value based on the current charge / discharge power or the power setting value of the previous cycle, combined with the power deviation and the feedforward compensation power value.

[0036] Choose one of two selectable feedback reference power values, and then superimpose this reference value with the power deviation calculated in the second step and the feedforward compensation power value generated in the third step to obtain a preliminary power command value. This value is called the base power setpoint, which reflects the theoretically required power output of the energy storage converter without any regulation rate limitations.

[0037] In this embodiment, one of two alternative values ​​is selected as the feedback reference power value. The first alternative is the current real-time charging and discharging power of the energy storage system, which is directly obtained from the energy storage converter and reflects the actual output power of the energy storage device. The second alternative is the power setpoint issued in the previous control cycle, which is stored in the memory of the energy management system and reflects the target power that the system hoped the energy storage would achieve at the previous moment. In actual implementation, one method can be fixed based on the response speed of the field equipment and the quality of the data collected, or a judgment condition can be set to determine which method to use. Regardless of which one is selected, this reference value represents the starting point of the current control cycle.

[0038] The base power setpoint is obtained by adding the selected feedback reference power value, the calculated power deviation, and the generated feedforward compensation power value. In formulaic terms, the base power setpoint equals the feedback reference power value plus the power deviation plus the feedforward compensation power value. The power deviation eliminates existing errors, bringing the total power meter reading closer to the anti-backflow target value. The feedforward compensation power value proactively offsets external disturbances, allowing the system to activate before the disturbance arrives.

[0039] For example, using the data from the previous example, the current charge / discharge power is 100 kW, and the power setting value of the previous cycle is also 100 kW; the two values ​​are identical. The power deviation is 150 kW, and the feedforward compensation power value is 3.6 kW. Assuming that the current charge / discharge power is selected as the feedback benchmark based on the site conditions, the base power setting value equals 100 kW plus 150 kW plus 3.6 kW, resulting in 253.6 kW. If the power setting value of the previous cycle is selected as the feedback benchmark due to a large power recovery delay, the base power setting value equals 100 kW plus 150 kW plus 3.6 kW, also resulting in 253.6 kW. This value of 253.6 kW means that, without any restrictions, the system expects the energy storage converter to discharge at a power of 253.6 kW.

[0040] The feedback reference provides the current operating point, deviation compensation achieves error-free convergence to the target value, and feedforward compensation enables early cancellation of disturbances. The combination of these three features ensures that the base power setpoint considers the current real-time state, includes the adjustment required to eliminate errors, and is pre-loaded with compensation to combat disturbances. The ability to select between two feedback references allows this method to adapt to different hardware configurations: real-time power is used when power retrieval is fast and accurate, resulting in higher control precision; the previous cycle setpoint is used when power retrieval is slow or has a significant delay, avoiding control oscillations caused by delays. This flexibility improves the applicability and robustness of the method.

[0041] Step S5: Asymmetric rate adjustment is performed on the basic power setting value. When the power deviation is greater than zero, a gradual increase adjustment method is used, and when the power deviation is less than or equal to zero, a rapid decrease adjustment method is used to obtain the adjusted power setting value.

[0042] The speed of adjustment is determined by the sign of the power deviation obtained from S2: if the power deviation is positive, it indicates that discharge needs to be increased or charging needs to be reduced, and a slow increase is used to approach the target; if the power deviation is negative or zero, it indicates that discharge needs to be reduced or charging needs to be increased to suppress reverse current, and a rapid decrease is used to respond directly. The result after this asymmetric processing is called the adjusted power setpoint.

[0043] In this embodiment, the sign of the power deviation is determined. If the power deviation is greater than zero, the system is in a state where it has not yet reversed the flow or has absorbed too much power from the grid. In this case, energy storage is needed to increase discharge or reduce charging. However, to avoid system oscillation caused by sudden power changes, a gradual increase adjustment method is adopted. The idea of ​​gradual increase adjustment is to limit the single change amplitude of the power command, that is, the change in the power value after this adjustment relative to the base power setting value cannot exceed a preset small step size. There are various specific implementation methods, such as taking the smaller value between the power deviation and the preset step size as the adjustment amount, or reducing the power deviation by a certain proportion as the adjustment amount, but their common characteristics are that the adjustment speed is slow and the change is smooth.

[0044] If the power deviation is less than or equal to zero, the system is already in a reverse current state or about to experience reverse current. In this case, the energy storage system needs to immediately reduce discharge or increase charging to eliminate the reverse current, employing a rapid descent regulation method. The idea behind rapid descent regulation is to not impose any restrictions on the adjustment range, but directly add the entire value of the power deviation to the base power setpoint, ensuring that the energy storage power command is delivered in one go and responds quickly. This asymmetric processing logic ensures smooth action in the safe direction and rapid action in the dangerous direction, thus maintaining system stability while promptly suppressing reverse current.

[0045] For example, using the aforementioned example data, the base power setting is 253.6 kW, and the power deviation calculated in the second step is 150 kW (greater than zero). Therefore, a gradual increase adjustment method is adopted. The system's preset maximum single adjustment step size is 10 kW. The smaller value of 10 kW is taken as the adjustment amount after comparing the power deviation of 150 kW with the step size of 10 kW. Adding 10 kW to the base power setting of 253.6 kW yields the adjusted power setting of 263.6 kW. This means that although the theoretical calculation requires 253.6 kW of energy storage discharge, only 10 kW of discharge power is actually added, and the remaining 140 kW will be gradually released in subsequent control cycles.

[0046] Consider another scenario: a sudden jump in the total power meter reading causes a power deviation of -30 kW (i.e., 30 kW of reverse current). In this case, let's assume the base power setpoint is a certain value (e.g., 80 kW). Since the power deviation is less than zero, a rapid reduction adjustment method is used. The entire power deviation of -30 kW is directly taken as the adjustment amount and added to the base power setpoint, resulting in an adjusted power setpoint of 50 kW (i.e., a reduction of 30 kW in discharge or an increase of 30 kW in charging). This change is completed within one cycle, the energy storage power drops rapidly, and the reverse current is quickly suppressed.

[0047] Step S6: The adjusted power setting value is limited according to the upper and lower limits of the energy storage system power to obtain the final power command, which is then sent to the energy storage converter for execution.

[0048] The adjusted power setting value obtained from S5 is subjected to a safety check to ensure that its value does not exceed the maximum allowable discharge power and maximum charging power of the energy storage converter. If the adjusted power setting value exceeds the allowable range, it is forcibly limited to the boundary value; if it does not exceed the limit, it remains unchanged. The value after limiting is the final power command, which is then sent to the energy storage converter to perform the corresponding charging and discharging operations.

[0049] In this embodiment, two inherent parameters of the energy storage converter are obtained: maximum discharge power and maximum charging power. Maximum discharge power is a positive value, representing the maximum discharge power the converter can output (e.g., 500 kW). Maximum charging power is a negative value, representing the maximum charging power the converter can absorb (e.g., -500 kW), meaning the absolute value of the charging power cannot exceed this limit. These two parameters are typically provided by the converter manufacturer and pre-stored in the parameter table of the energy management system.

[0050] The adjusted power setting obtained in step five is compared with these two limits. If the adjusted power setting is greater than the maximum discharge power, it means the required discharge power exceeds the converter's physical capacity; in this case, the final power command is set to the maximum discharge power. If the adjusted power setting is less than the maximum charging power, it means the absolute value of the required charging power exceeds the converter's absorption capacity; in this case, the final power command is set to the maximum charging power (a negative value). If the adjusted power setting is between the two limits, it is directly used as the final power command without any modification.

[0051] The final power command is sent to the energy storage converter via a communication protocol (such as Modbus, CAN, or IEC61850). After receiving the command, the converter adjusts its output or input power according to the command value, completing a full control closed loop.

[0052] For example, following the S5 gradual increase adjustment example, the adjusted power setting is 263.6 kW (discharge direction). The maximum discharge power of the energy storage converter is 500 kW, and the maximum charging power is -500 kW. Since 263.6 kW is less than 500 kW and greater than -500 kW, it is within the allowable range, so the limiting processing remains unchanged, and the final power command is 263.6 kW. After this command is issued, the converter will gradually increase the discharge power from the current 100 kW to 263.6 kW.

[0053] Consider another scenario: Due to some malfunctioning calculation, the adjusted power setting reaches 600 kW, exceeding the 500 kW upper limit. In this case, the limiting process will force the final power command to 500 kW to prevent inverter overload. Now assume the adjusted power setting is -600 kW (i.e., 600 kW charging), below the -500 kW lower limit. The limiting process will force it to -500 kW to ensure the inverter's charging power does not exceed the safe range.

[0054] This application generates feedforward compensation by collecting the power change trend of disturbance sources, enabling the energy storage system to adjust in advance at the initial stage of load or photovoltaic sudden change, significantly shortening the response lag and effectively eliminating transient backflow. Combined with asymmetric rate adjustment, it ensures that the total meter power is stable near the anti-backflow target value and does not exceed the limit, avoiding backflow fluctuations caused by power ride-through. For photovoltaic-energy storage integration scenarios, when the energy storage state of charge is close to the upper limit, the charging power limit is gradually reduced according to the deviation ratio, reserving time for photovoltaic power adjustment in advance to prevent power backflow at the moment of full charging of energy storage. At the same time, by adaptively increasing the gradual increase step size when the power deviation sign is continuously in the same direction and restoring the step size when the sign changes, the dynamic tracking speed and control stability are further improved.

[0055] In some optional implementations of this embodiment, the step of generating the feedforward compensation power value includes: Calculate the difference between the total power at the current time and the previous time. When the absolute value of the difference is greater than a preset first threshold, a feedforward compensation power value is generated based on the magnitude of the difference, and the feedforward compensation power value is positively correlated with the magnitude of the difference and the total response delay time of the energy storage system. When the absolute value of the difference is less than or equal to the first threshold, the feedforward compensation power value is set to zero.

[0056] In this embodiment, the real-time value of the total power meter is obtained in each control cycle, and the value of the previous cycle is stored.

[0057] Calculate the difference between the total meter power at the current time and the total meter power at the previous time. This difference reflects the direction and magnitude of the change in total meter power. Let the total meter power at the current time be P. m(t) The previous time step was P. m(t-1) Then the difference ΔP m =P m(t) -P m(t-1) .

[0058] The absolute value of this difference is compared with a preset first threshold. The first threshold is a positive number used to determine whether the disturbance is significant, for example, 5 kilowatts. If |ΔP m If |≤ the first threshold, the disturbance is considered small, and no feedforward compensation is generated, i.e., the feedforward compensation power value P ff Set it to zero. If |ΔP m If the first threshold is reached, a feedforward compensation power value is generated proportionally based on the magnitude of the difference. This compensation value is related to the difference and the system's total response delay time T. delay Positive correlation. Their mathematical relationship can be expressed as: in, The generated feedforward compensation power value is in kilowatts; The feedforward coefficient is a dimensionless positive number, typically ranging from 0 to 1, used to adjust the compensation strength; a typical value is 0.8. The total power is the difference between the current time and the previous time, in kilowatts. Its positive or negative sign indicates an increase or decrease in power. The total system response delay, in seconds, includes the sum of data sampling delay, communication transmission delay, and energy storage converter execution delay.

[0059] The faster the total power changes (the larger the absolute value of the difference), the larger the feedforward compensation value; the greater the system delay, the larger the compensation value, to compensate for the impact of lag. The sign of the compensation value is the same as the sign of the difference value, that is, when the total power increases, the feedforward compensation value is positive, indicating that it is necessary to increase energy storage discharge (or reduce charging) to offset the upward trend; when the total power decreases, the feedforward compensation value is negative, indicating that it is necessary to reduce discharge (or increase charging) to prevent excessive decrease leading to reverse current.

[0060] For example, suppose the system control cycle is 2 seconds, and the total power P at the previous moment... m(t-1) =120kW, current time P m(t) =150kW, then ΔP m =30kW. The first threshold is set to 5kW; 30 > 5, so the condition is met. Feedforward coefficient K ff =0.8, total response delay time T delay =0.15s. Substituting into the formula: P ff =0.8×30×0.15=3.6kW. This positive value means that the feedforward compensation command increases the energy storage discharge by 3.6kW.

[0061] Assume another scenario: the total power suddenly drops from 150kW to 90kW, then ΔP m =-60kW, absolute value greater than 5kW. P ff =0.8×(-60)×0.15=-7.2kW. The negative value indicates that the feedforward compensation command reduces the discharge of the energy storage by 7.2kW (or increases the charging), preventing reverse current in advance.

[0062] This application, by introducing first-order differential and proportional delay compensation, can effectively predict power surge trends, adjust energy storage output in advance, significantly shorten control lag, and avoid transient backflow. The feedforward coefficient can be flexibly adjusted according to on-site commissioning, achieving a balance between system response speed and stability.

[0063] In some optional implementations of this embodiment, the disturbance source is a photovoltaic power generation system, and the step of generating the feedforward compensation power value includes: Obtain the photovoltaic power and calculate the difference between the photovoltaic power at the current time and the photovoltaic power at the previous time. When the absolute value of the photovoltaic power difference is greater than a preset second threshold, a feedforward compensation power value is generated based on the magnitude of the photovoltaic power difference. The feedforward compensation power value is positively correlated with the magnitude of the photovoltaic power difference and the total response delay time of the energy storage system, and the sign of the feedforward compensation power value is opposite to the sign of the photovoltaic power difference. When the absolute value of the photovoltaic power difference is less than or equal to the second threshold, the feedforward compensation power value is set to zero.

[0064] In this embodiment, the real-time output power of the photovoltaic power generation system is collected in each control cycle, denoted as P. pv(t) And store the value P from the previous period. pv(t-1) Calculate the photovoltaic power difference ΔP pv =P pv(t) -P pv(t-1) A positive difference indicates an increase in photovoltaic power output, while a negative difference indicates a decrease.

[0065] The absolute value of this difference is compared with a preset second threshold. The second threshold is a positive number, such as 5kW, used to determine whether photovoltaic fluctuations are significant. If |ΔP pv If |≤ the second threshold, then the feedforward compensation value is set to zero, and no compensation is performed.

[0066] If |ΔP pv If the second threshold is reached, a feedforward compensation power value is generated based on the difference. This compensation value is then compared with the difference and the system's total response delay time T. delay They are positively correlated, and the sign is opposite to that of the difference. Their mathematical relationship can be expressed as: in, This is the feedforward compensation power value, in kilowatts; This is the photovoltaic feedforward coefficient, a dimensionless positive number, with a typical value of 0.6~1.0; This represents the difference between the current photovoltaic power and the previous time, expressed in kilowatts. The total system response delay time is expressed in seconds.

[0067] For example, let the total system delay T be... delay =0.15s, photovoltaic feedforward coefficient K pv =0.7. At a certain moment, the photovoltaic power jumps from 150kW to 200kW due to increased sunlight, the difference ΔP pv =50kW, which is greater than the second threshold of 5kW. Therefore, P ff =-0.7×50×0.15=-5.25kW. A negative value indicates that the energy storage needs to be charged by 5.25kW or discharged by 5.25kW. This feedforward compensation will command the energy storage to charge more before the photovoltaic power actually affects the total meter, thereby avoiding the total meter power from dropping in the negative direction (reverse current) due to a sudden increase in photovoltaic power.

[0068] If the power output of a photovoltaic system drops sharply from 200kW to 120kW due to cloud cover, the difference ΔP pv =-80kW, the absolute value is greater than the threshold. Then P ff=-0.7×(-80)×0.15=+8.4kW. A positive value indicates that the energy storage charging needs to be reduced by 8.4kW or the discharging needs to be increased by 8.4kW to compensate for the lack of photovoltaic power and prevent the total meter power from becoming too high due to the sudden drop in photovoltaic power (too much power drawn from the grid).

[0069] This application, by directly collecting photovoltaic power and providing reverse compensation, enables energy storage to activate before changes in photovoltaic power are transmitted to the main meter, thereby significantly suppressing reverse current risks, improving photovoltaic grid integration efficiency, and avoiding grid impact. This feedforward method can coexist with the main meter power feedforward or be used independently, depending on site conditions.

[0070] In some optional implementations of this embodiment, the disturbance source is a load system, and the step of generating the feedforward compensation power value includes: Obtain the load power and calculate the difference between the load power at the current time and the load power at the previous time. When the absolute value of the load power difference is greater than a preset third threshold, a feedforward compensation power value is generated based on the magnitude of the load power difference. The feedforward compensation power value is positively correlated with the magnitude of the load power difference and the total response delay time of the energy storage system, and the sign of the feedforward compensation power value is opposite to the sign of the load power difference. When the absolute value of the load power difference is less than or equal to the third threshold, the feedforward compensation power value is set to zero.

[0071] In this embodiment, the real-time power of the total load on the user side is collected and denoted as P. load(t) And store the value P from the previous period. load(t-1) Calculate the load power difference ΔP load =P load(t) -P load(t-1) A positive difference indicates an increase in load, while a negative difference indicates a decrease in load. The absolute value of the difference is compared with a preset third threshold. If |ΔP load If |≤ the third threshold, the feedforward compensation value is set to zero; if it is greater than the threshold, a feedforward compensation value is generated.

[0072] For example, suppose the total system delay is 0.15s and the load feedforward factor is 0.6. At a certain moment, a high-power device starts up, causing the load to jump from 200kW to 350kW, a power difference of 150kW, which is greater than the preset threshold of 10kW. Then, the feedforward compensation power value P... ff=-0.6×150×0.15=-13.5kW. A negative value indicates that an additional 13.5kW of energy storage discharge is needed (or a reduction in charging) to quickly respond to load increases and avoid excessive power absorption from the grid (i.e., to avoid positive overshoot of the total meter power). If equipment shutdown causes the load to drop sharply from 300kW to 100kW, the load power difference is -200kW, then the feedforward compensation power value P... ff =-0.6×(-200)×0.15=+18kW. A positive value indicates that the energy storage discharge needs to be reduced by 18kW or the charging needs to be increased by 18kW to absorb the excess power generated by the sudden load drop and prevent backflow.

[0073] Sudden changes in load power are common and unpredictable disturbances in industrial and commercial settings. Direct load feedforward compensation can achieve near-real-time power balance. This application, by directly measuring load changes, allows energy storage to begin adjusting simultaneously with load changes, compared to relying solely on main meter power feedback. Theoretically, this can eliminate backflow or power spikes caused by sudden load changes. It is particularly suitable for applications with frequent load fluctuations, such as welding workshops, stamping equipment, and elevator groups.

[0074] In some optional implementations of this embodiment, the above-mentioned gradual increase adjustment method is specifically as follows: When the absolute value of the power deviation is less than or equal to the first adjustment threshold, the power deviation is compared with the preset maximum single adjustment step size, and the smaller of the two values ​​is taken as the adjustment amount for this time. When the absolute value of the power deviation is greater than the first adjustment threshold and less than or equal to the second adjustment threshold, half of the power deviation is used as the adjustment amount for this adjustment, but not exceeding the preset maximum single adjustment step size. When the absolute value of the power deviation is greater than the second adjustment threshold, the preset fast adjustment threshold is adjusted once, and then the difference between the power deviation and the fast adjustment threshold is processed according to the adjustment method when the absolute value of the power deviation is less than or equal to the first adjustment threshold.

[0075] In this embodiment, three key parameters are preset: a first adjustment threshold, a second adjustment threshold, a maximum single adjustment step size, and a fast adjustment threshold. The first adjustment threshold is less than the second adjustment threshold. Then, based on the absolute value of the current power deviation ΔP, three cases are handled.

[0076] Scenario 1: When |ΔP| ≤ the first adjustment threshold, the deviation is considered small, and a linear gradual increase is adopted. The adjustment amount is the smaller of the power deviation and the preset maximum single adjustment step size. That is, if the deviation is less than the step size, the adjustment is completed in one step; if the deviation is greater than the step size, only one step size is adjusted. The adjusted power setpoint = base power setpoint + this adjustment amount.

[0077] Scenario 2: When the first adjustment threshold <|ΔP| ≤ the second adjustment threshold, the deviation is considered moderate, and a half-amplitude gradual increase is adopted. The adjustment amount is half of the power deviation, but this half value cannot exceed the maximum single adjustment step size. That is, the adjustment amount = min(|ΔP| / 2, step size), and the direction is the same as ΔP. ​​This method can respond quickly without overshooting when the deviation is large.

[0078] Scenario 3: When |ΔP| > the second adjustment threshold, the deviation is considered large, and a fast-then-slow strategy is adopted. First, a fixed fast-adjustment threshold amount (e.g., 100kW) is adjusted at once. Then, the remaining deviation (i.e., the original deviation minus the fast-adjustment threshold amount) is processed in the manner of Scenario 1 (linear gradual increase). This method can quickly bring the power close to the target under extreme deviations, and then fine-tune it.

[0079] For example, suppose the first adjustment threshold is 20kW, the second adjustment threshold is 100kW, the maximum single adjustment step is 10kW, and the fast adjustment threshold is 100kW. The current base power setting is 200kW.

[0080] If ΔP = 15kW (|ΔP| ≤ 20), use case one: adjustment amount = min(15, 10) = 10kW, and the power setting value after adjustment = 200 + 10 = 210kW.

[0081] If ΔP = 60kW (20 < 60 ≤ 100), use case two: adjustment amount = min(60 / 2, 10) = min(30, 10) = 10kW, and the power setting value after adjustment = 200 + 10 = 210kW (although the half amplitude is 30, it is limited by the step size).

[0082] If ΔP = 150kW (>100), use Case 3: First, adjust the fast adjustment threshold by 100kW to obtain a temporary value of 200 + 100 = 300kW; the remaining deviation = 150 - 100 = 50kW. Then, proceed as in Case 1: the adjustment amount = min(50, 10) = 10kW, and the final adjusted power setpoint = 300 + 10 = 310kW. The entire process is completed within one cycle.

[0083] This application employs a segmented gradual increase strategy, ensuring smooth adjustment under small deviations while rapidly approaching the target under large deviations, thus avoiding the slow response issue of a single linear gradual increase under large deviations. Half-amplitude gradual increase balances speed and stability under moderate deviations, while the fast-then-gradient strategy is a solution for emergency situations (such as severe power deviations). Seamless switching between the three strategies requires no manual intervention, improving the system's adaptability and dynamic quality.

[0084] In some optional implementations of this embodiment, for energy storage systems connected to photovoltaic power generation systems, a step of pre-limiting charging power is also included: Obtain the state of charge (SOC) of the energy storage battery and set the upper limit of SOC and the loopback width; When the state of charge is greater than or equal to the upper limit of the state of charge, the charging power limit is set to zero; When the state of charge is within the range of the upper limit of the state of charge minus the loopback width to the upper limit of the state of charge, the charging power limit value is gradually reduced according to the ratio of the difference between the state of charge and the upper limit of the state of charge to the loopback width. The adjusted power setting value is compared with the charging power limit value, and the larger value is taken as the final power command.

[0085] In this embodiment, the state of charge (SOC) of the energy storage battery is acquired in real time (expressed as a percentage, e.g., 0% to 100%). Two parameters are preset: an upper limit value for the SOC. up (e.g., 95%) and loopback width SOC zone (For example, 5%). The loopback region refers to the area from the SOC. up -SOC zone To SOC up The area between.

[0086] Determine the interval where SOC lies; if SOC ≥ SOC up This indicates that the battery is fully charged, and the charging power limit should be set to 0, which means that any charging should be prohibited.

[0087] If the SOC is within the loopback region, i.e., the SOC up -SOC zone <SOC<SOC up Then, based on the difference between SOC and the upper limit value, SOC del =SOC up -The proportion of SOC to the loopback width gradually reduces the charging power limit.

[0088] For example, multiple steps can be defined: when SOC del >0.9×SOC zone When the SOC is reached, the charging power is limited to 80% of the maximum charging power; when the SOC is reached... del >0.7×SOC zone When, the limit is 60%; when SOC del >0.5×SOC zone When, the limit is 40%; when SOC del >0.4×SOC zone At that time, the limit is 20%. The specific division of the tiers can be adjusted according to the actual battery characteristics and system requirements.

[0089] If SOC≤SOCup -SOC zone If no additional restrictions are imposed, the charging power limit value is equal to the rated maximum charging power (negative value, such as -500kW).

[0090] Finally, the adjusted power setting value is compared with the charging power limit value, and the larger of the two values ​​is taken as the final power command. Note that since the charging power is a negative value (for example, -100kW means charging at 100kW), taking the larger value means limiting the depth of charging (for example, -100kW is greater than -300kW, so the limit of -100kW is more stringent).

[0091] For example, suppose a photovoltaic-storage system has a rated energy storage power of 300kW (i.e., maximum charging power -300kW, maximum discharging power +300kW). Set the State of Charge (SOC). up =95%, SOC zone =5%.

[0092] Current SOC = 93%, calculate SOC. del =95%-93%=2%. The loop width is 5%, and 2% is 0.4% of 5%. According to the ladder rule, 0.4 falls exactly on the boundary of "greater than 0.4" (assuming that using >0.4 would trigger the 20% limit, but in the example, it is usually set to greater than or equal to a certain value).

[0093] Let the step be: SOC del >0.9 * 5% = 4.5% → 80% limit; >0.7 * 5% = 3.5% → 60% limit; >0.5 * 5% = 2.5% → 40% limit; >0.4 * 5% = 2% → 20% limit. Current SOC del =2% equals 2%, triggering the 20% limit, meaning the charging power limit is -300kW × 20% = -60kW.

[0094] Assume the adjusted power setting is -200kW (meaning 200kW of charging is required). Taking the larger of the two values: max(-200, -60) = -60kW. Therefore, the final power command is -60kW, meaning only 60kW of charging is allowed, and the remaining 140kW of charging demand is postponed. This gives the photovoltaic inverter time to reduce its output and prevent reverse current.

[0095] This application reduces the charging power limit in stages as the SOC approaches its upper limit, avoiding the shock of sudden jumps from full-power charging to zero charging in traditional methods. This allows the photovoltaic inverter time to respond (e.g., during startup power limiting or curtailment), thus completely eliminating reverse current phenomena. Furthermore, the loopback width and step ratio can be flexibly adjusted according to the battery aging level or photovoltaic response speed, exhibiting strong engineering adaptability.

[0096] In some optional implementations of this embodiment, exception handling steps are also included: When the data sampling of the total power meter fails or communication is interrupted, the power command of the previous cycle is retained; When the duration of the failure to sample the total power data or the communication interruption exceeds a preset time threshold, the energy storage system will be switched to a preset standby power mode.

[0097] In this embodiment, the validity of the total power data and the communication status with the energy storage converter are continuously monitored. If data sampling fails (e.g., the energy meter does not respond, or the data is outside a reasonable range) or communication is interrupted (e.g., unable to send commands to the energy storage converter), the exception handling logic is immediately triggered.

[0098] When an anomaly first occurs, a conservative strategy is adopted: the power command from the previous cycle remains unchanged, meaning the energy storage continues to operate according to the last issued command. This avoids sudden changes in commands due to missing data, preventing impact on the power grid or equipment.

[0099] Simultaneously, a timer is started to record the duration of the anomaly. If the anomaly duration does not exceed a preset time threshold (e.g., 10 seconds), the previous cycle's command is maintained. Once the anomaly duration exceeds this threshold, the system determines it as a serious fault, at which point the energy storage system switches to a preset standby power mode. The standby power mode is typically a safe, fixed value, such as 0kW (i.e., charging and discharging stop), or a preset minimum power (e.g., 5kW discharge), the specific value of which is set according to site safety requirements. After the anomaly is cleared, the system automatically resumes normal control procedures.

[0100] For example, suppose an energy storage system has a control cycle of 2 seconds and a preset time threshold of 10 seconds (i.e., 5 control cycles). In one cycle, due to a momentary communication failure of the electricity meter, the total meter power data cannot be read. At this time, the system immediately initiates anomaly handling: maintaining the power command of the previous cycle (assuming the previous cycle command was to discharge 80kW). After 4 consecutive cycles (8 seconds), communication has still not been restored, but the 10-second threshold has not been exceeded, so the system continues to discharge 80kW. When the 6th cycle (12 seconds) arrives, the anomaly duration has exceeded 10 seconds, and the system switches the energy storage to a standby power mode, for example, 0kW (stop charging and discharging). Subsequently, communication is restored, the system detects that the data is valid, automatically exits the anomaly mode, and restarts the normal control process.

[0101] This application employs an anomaly handling mechanism to endow the anti-backflow control method with basic fault tolerance. Short-term maintenance of the previous cycle's command avoids unnecessary adjustments caused by brief communication jitter; long-term switching to backup power prevents potential runaway risks (such as backflow or overload due to blind charging / discharging) when critical data is unavailable. This method is simple, reliable, requires no additional hardware, and is applicable to various unforeseen anomalies in engineering settings, enhancing the system's robustness and safety.

[0102] In some optional implementations of this embodiment, the total response delay of the energy storage system includes the sum of data sampling delay, communication transmission delay, and energy storage converter execution delay, which is obtained through pre-testing.

[0103] In this embodiment, the total response delay time T delay Defined as the sum of three parts: T delay =T sample +T comm +T exec Among them, T sample Data sampling delay refers to the time required from the generation of a signal by the main meter or photovoltaic sensor to the energy management system (EMS) completing the analog-to-digital conversion and reading the data. It is typically determined by the hardware characteristics of the sampling circuit and communication interface; for example, a meter using RS485 communication may have a delay of 100ms. comm Communication transmission delay refers to the time it takes for the energy management system to send calculated power commands to the energy storage converter and receive confirmation. This delay depends on the communication protocol and bus load; for example, CAN communication typically takes 10-50ms, while Ethernet may take 1-10ms. exec The execution delay of an energy storage converter refers to the response time required for the converter's internal controller to complete the adjustment and bring the actual output power to the commanded value after receiving a command. This value is usually determined by the converter's control algorithm and the dynamic characteristics of the power devices, and is generally between 50ms and 200ms.

[0104] The three delays mentioned above can be obtained through pre-testing. Specific testing methods include: using an oscilloscope or a high-precision timestamp to record the difference between the data sampling trigger time and the EMS read completion time to obtain T. sample The difference between the time the command is issued and the time the converter confirms receipt is recorded to obtain T. comm The difference between the time the instruction was issued and the time when the actual power changed to 90% of the target value, minus the former two, yields T. exec The sum of the three values ​​gives the total response delay time.

[0105] For example, the delay parameters of a certain system obtained through field testing are as follows: The electricity meter uses Modbus RTU communication with a sampling period of 200ms, but there is an alignment delay of one cycle when the EMS reads the data. The measured T sample =220ms (including waiting and conversion). Communication uses Ethernet, and the time T from command issuance to confirmation of receipt is... comm =8ms. The power response time of the energy storage converter (from command to actual power reaching 90% of the target value) is T. exec =70ms. Therefore, the total response delay time T delay =220+8+70=298ms, approximately 0.3 seconds. This value will be used directly in the feedforward calculation.

[0106] This application clarifies the composition of the total response delay time and its acquisition method, thus providing a physical basis for feedforward compensation calculations and avoiding over- or under-compensation caused by arbitrarily setting parameters. Pre-testing allows for the quantification of delay differences caused by different devices and communication methods, enabling accurate setting of feedforward coefficients in different environments to ensure optimal feedforward compensation. It also provides a quantitative reference for system debugging and fault diagnosis.

[0107] In some optional implementations of this embodiment, the above-mentioned rapid reduction adjustment method is: the power deviation is used as the current adjustment amount and directly added to the basic power setting value.

[0108] In this embodiment, when the power deviation ΔP ≤ 0, the calculation formula for the rapid descent regulation is as follows: in, The adjusted power setting value; The base power setting value (from step four of claim 1); Power deviation (negative or zero), in kilowatts.

[0109] The required reduction in discharge (or increase in charging) is reflected in the power command all at once, without delay. For example, if the base power setting is 100kW for discharge and the power deviation is -30kW (indicating a 30kW reverse current), the adjusted power setting will directly become 70kW (discharge reduced by 30kW). If the base power setting is 20kW for discharge and the power deviation is -50kW, the adjusted power setting will become -30kW (i.e., switching to 30kW charging).

[0110] This adjustment method is not constrained by any step size parameters, nor does it perform filtering or limiting (except for the final power upper and lower limit protection). The goal is to eliminate backflow in the shortest possible time.

[0111] For example, suppose that in a certain control cycle, the base power setpoint is 80kW (discharge), and the power deviation ΔP = -45kW. Rapid descent regulation is used: P adj =80 + (-45) = 35kW. That is, the discharge power immediately drops from 80kW to 35kW, a reduction of 45kW in discharge. If the base power setting for another scenario is 50kW (discharge), ΔP = -70kW, then P adj =50-70=-20kW, meaning the discharge power directly changes from 50kW to 20kW. This command is executed in the next control cycle, and the reverse current is suppressed in the shortest possible time.

[0112] This application clarifies the direct arithmetic superposition characteristics of sag regulation, ensuring maximum regulation speed during critical backflow situations. Compared to symmetrical regulation or rate limiting, full superposition can compensate for backflow deviation within one control cycle, significantly shortening the backflow duration. Furthermore, since sag regulation is only triggered when the power deviation is negative, and a negative deviation usually indicates backflow has already occurred, the primary objective of the system at this point is safety rather than smoothness; therefore, full superposition is the most reasonable choice.

[0113] In some optional implementations of this embodiment, the maximum single adjustment step size in the above-described gradual increase adjustment method is adjusted according to the fluctuation of the power deviation: When the power deviation remains the same sign for multiple consecutive control cycles, the maximum single adjustment step size is gradually increased. When the sign of the power deviation changes, the maximum single adjustment step size is restored to its initial value.

[0114] In this embodiment, a basic maximum single adjustment step size is set, denoted as P. step0 (For example, 10kW). The system then continuously monitors the sign of the power deviation ΔP. A counter N is defined that maintains the same sign for multiple consecutive control cycles. N is incremented by 1 whenever the sign of ΔP is the same as in the previous cycle; N is reset to zero when the sign changes.

[0115] In each control cycle, the actual maximum single adjustment step size P is adjusted according to the magnitude of N. step : When N is small (e.g., N<3), use the initial step size P. step0 .

[0116] Once N reaches a certain threshold, the step size is gradually increased. For example, when N=3, P... step =1.5×P step0 When N=5, P step =2×P step0 Until the preset maximum allowable step size P is reached. step_max (e.g., 5×P) step0Or 50kW).

[0117] Once the power deviation sign changes (i.e., N is cleared to zero), immediately change P... step Restore to the initial value P step0 .

[0118] This adaptive rule enables the system to distinguish between unidirectional, continuous load changes (such as continuous loading after high-power equipment starts up) and oscillating changes (such as frequent load fluctuations). Increasing the step size during unidirectional changes allows for faster trend tracking; decreasing the step size during oscillations avoids overshoot and oscillations.

[0119] For example, let the initial maximum single adjustment step size P be... step0 =5kW, maximum allowable step size P step_max =20kW. System control cycle 2 seconds.

[0120] Scenario A: The load continues to increase, causing the power deviation ΔP to be positive for several consecutive cycles. In the first cycle, N=1, with a step size of 5kW; in the second cycle, ΔP is still positive, N=2, with a step size of 5kW; in the third cycle, N=3, and the step size becomes 5×1.5=7.5kW; in the fifth cycle, N=5, and the step size becomes 5×2=10kW; in the tenth cycle, N=10, and the step size gradually increases to 20kW. The energy storage discharge power increases at an increasingly rapid rate, quickly keeping up with the load changes.

[0121] Scenario B: Frequent load fluctuations and alternating signs of power deviation. In the first cycle, N=1, with a step size of 5kW; in the second cycle, the sign changes, N is reset to zero, and the step size remains at 5kW; in the third cycle, the sign changes again, N is reset to zero, and the step size remains at 5kW. The step size is consistently 5kW, ensuring smooth adjustment and preventing overshoot due to excessively large step sizes.

[0122] This application effectively resolves the contradiction between dynamic response and stability in fixed step sizes by introducing adaptive step size adjustment based on the persistence of deviation signs. When power fluctuates significantly in one direction, the step size is automatically increased to improve tracking speed and prevent long-term deviation from the target due to slow adjustment. When power oscillates frequently, a small step size is automatically maintained to avoid overshoot and oscillation. This adaptive mechanism requires no complex modeling, can be implemented using only sign information, is computationally simple, and is easy to implement in embedded controllers, significantly improving the adaptability of gradual adjustment under various operating conditions.

[0123] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A method for preventing backflow control in an industrial and commercial energy storage system, characterized in that, Includes the following steps: Collect the total power of the energy storage system, the current charging and discharging power, the power setpoint of the previous cycle, and the anti-reverse current target power value; Calculate the power deviation between the total power meter reading and the anti-backflow target power value; Acquire real-time power data of the disturbance source, process the real-time power data to obtain the power change trend of the disturbance source, and generate a feedforward compensation power value based on the power change trend; Based on the current charging / discharging power or the power setting value of the previous cycle, combined with the power deviation and the feedforward compensation power value, the base power setting value is calculated. The basic power setting value is adjusted at an asymmetric rate. When the power deviation is greater than zero, a gradual increase adjustment method is used, and when the power deviation is less than or equal to zero, a rapid decrease adjustment method is used to obtain the adjusted power setting value. The adjusted power setting value is limited according to the upper and lower limits of the energy storage system power to obtain the final power command, which is then sent to the energy storage converter for execution.

2. The backflow prevention control method for an industrial and commercial energy storage system according to claim 1, characterized in that, The step of generating the feedforward compensation power value includes: Calculate the difference between the total power at the current time and the previous time. When the absolute value of the difference is greater than a preset first threshold, a feedforward compensation power value is generated based on the magnitude of the difference, and the feedforward compensation power value is positively correlated with the magnitude of the difference and the total response delay time of the energy storage system. When the absolute value of the difference is less than or equal to the first threshold, the feedforward compensation power value is set to zero.

3. The backflow prevention control method for an industrial and commercial energy storage system according to claim 1, characterized in that, The disturbance source is a photovoltaic power generation system, and the step of generating the feedforward compensation power value includes: Obtain the photovoltaic power and calculate the difference between the photovoltaic power at the current time and the photovoltaic power at the previous time. When the absolute value of the photovoltaic power difference is greater than a preset second threshold, a feedforward compensation power value is generated based on the magnitude of the photovoltaic power difference. The feedforward compensation power value is positively correlated with the magnitude of the photovoltaic power difference and the total response delay time of the energy storage system, and the sign of the feedforward compensation power value is opposite to the sign of the photovoltaic power difference. When the absolute value of the photovoltaic power difference is less than or equal to the second threshold, the feedforward compensation power value is set to zero.

4. The backflow prevention control method for an industrial and commercial energy storage system according to claim 1, characterized in that, The disturbance source is a load system, and the step of generating the feedforward compensation power value includes: Obtain the load power and calculate the difference between the load power at the current time and the load power at the previous time. When the absolute value of the load power difference is greater than a preset third threshold, a feedforward compensation power value is generated based on the magnitude of the load power difference. The feedforward compensation power value is positively correlated with the magnitude of the load power difference and the total response delay time of the energy storage system, and the sign of the feedforward compensation power value is opposite to the sign of the load power difference. When the absolute value of the load power difference is less than or equal to the third threshold, the feedforward compensation power value is set to zero.

5. The backflow prevention control method for an industrial and commercial energy storage system according to claim 1, characterized in that, The specific method of gradual increase adjustment is as follows: When the absolute value of the power deviation is less than or equal to the first adjustment threshold, the power deviation is compared with the preset maximum single adjustment step size, and the smaller of the two values ​​is taken as the adjustment amount for this time. When the absolute value of the power deviation is greater than the first adjustment threshold and less than or equal to the second adjustment threshold, half of the power deviation is used as the adjustment amount for this adjustment, but not exceeding the preset maximum single adjustment step size. When the absolute value of the power deviation is greater than the second adjustment threshold, the preset fast adjustment threshold is adjusted once, and then the difference between the power deviation and the fast adjustment threshold is processed according to the adjustment method when the absolute value of the power deviation is less than or equal to the first adjustment threshold.

6. The backflow prevention control method for an industrial and commercial energy storage system according to claim 1, characterized in that, For energy storage systems connected to photovoltaic power generation systems, the charging power limitation step is also included: Obtain the state of charge (SOC) of the energy storage battery and set the upper limit of SOC and the loopback width; When the state of charge is greater than or equal to the upper limit of the state of charge, the charging power limit is set to zero; When the state of charge is within the range of the upper limit of the state of charge minus the loopback width to the upper limit of the state of charge, the charging power limit value is gradually reduced according to the ratio of the difference between the state of charge and the upper limit of the state of charge to the loopback width. The adjusted power setting value is compared with the charging power limit value, and the larger value is taken as the final power command.

7. The backflow prevention control method for an industrial and commercial energy storage system according to claim 1, characterized in that, It also includes exception handling steps: When the data sampling of the total power meter fails or communication is interrupted, the power command of the previous cycle is retained; When the duration of the failure to sample the total power data or the communication interruption exceeds a preset time threshold, the energy storage system will be switched to a preset standby power mode.

8. A method for preventing backflow control in an industrial and commercial energy storage system according to any one of claims 2 to 4, characterized in that, The total response delay of the energy storage system includes the sum of data sampling delay, communication transmission delay, and energy storage converter execution delay, which is obtained through pre-testing.

9. The backflow prevention control method for an industrial and commercial energy storage system according to claim 1, characterized in that, The rapid reduction adjustment method is as follows: the power deviation is used as the adjustment amount for this adjustment and directly added to the basic power setting value.

10. The anti-backflow control method for an industrial and commercial energy storage system according to claim 1, characterized in that, The maximum single adjustment step size in the gradual increase adjustment method is adjusted according to the fluctuation of the power deviation: When the power deviation remains the same sign for multiple consecutive control cycles, the maximum single adjustment step size is gradually increased. When the sign of the power deviation changes, the maximum single adjustment step size is restored to its initial value.

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