A power optimization distribution method and system of a single-phase light storage hybrid system

Abstract

The application discloses a power optimization distribution method and system of a single-phase light storage hybrid system, and belongs to the technical field of single-phase light storage hybrid system control. The method comprises the following steps: acquiring real-time power generation power and receiving a power balance enabling signal; judging whether to enter a power compensation mode according to the signal and a compensation capacity indication bit of an energy storage unit; if yes, calculating a power average value according to the real-time power generation power, and calculating a difference value; controlling each energy storage unit and a photovoltaic module to perform or not to perform power compensation according to the difference value and a state of charge of the energy storage unit; if no, controlling each energy storage unit to perform power recovery, exit operation or not to act according to the state of charge of each energy storage unit; and updating the compensation capacity indication bit after completion and performing the cycle. According to the application, photovoltaic power deviation is compensated in real time, the output power of each module is consistent, the power quality is optimized, the energy storage units are managed in layers according to the state of charge, and the safety and applicability of the energy storage are optimized.

Description

Technical Field

[0001] This invention belongs to the field of control technology for single-phase photovoltaic-storage hybrid systems, specifically relating to a power optimization allocation method and system for a single-phase photovoltaic-storage hybrid system. Background Technology

[0002] Currently, cascaded H-bridge converters are used in grid-connected photovoltaic power generation. Compared to traditional two-level and three-level converters, they offer better modularity and scalability, higher equivalent switching frequency, better power quality, and improved fault tolerance. However, because cascaded H-bridge converters use a series structure, inconsistent power generation from the photovoltaic modules connected to the DC side can affect the power quality at the grid connection point, potentially leading to overmodulation and system instability in severe cases.

[0003] Previous methods integrated energy storage systems into photovoltaic (PV) grid-connected inverters, optimizing the inverter's overmodulation by adjusting the energy storage system's power. However, when overmodulation doesn't occur, the energy storage system doesn't intervene in PV power regulation, failing to maximize its effectiveness. Therefore, currently, in the control of single-phase PV-energy storage hybrid systems, the system only intervenes after overmodulation occurs, making it difficult to achieve optimal power quality control, and the energy storage utilization rate needs further optimization. Summary of the Invention

[0004] This invention provides a power optimization allocation method and system for a single-phase photovoltaic-storage hybrid system, aiming to solve the problem that in the current control of single-phase photovoltaic-storage hybrid systems, the system only intervenes to regulate after overmodulation occurs, making it difficult to achieve optimal power quality control and requiring further optimization of energy storage utilization.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a power optimization allocation method for a single-phase photovoltaic-energy storage hybrid system. The single-phase photovoltaic-energy storage hybrid system includes a cascaded H-bridge converter and an energy storage unit. The method includes the following steps: Obtain the real-time power generation of each photovoltaic module and receive the power balancing enable signal; Based on the power balancing enable signal and the compensation capability indicator bit of the energy storage unit, determine whether to enter the power compensation mode; If so, the average power is calculated based on the real-time power generation of each photovoltaic module, and the difference between the real-time power generation of each photovoltaic module and the average power is calculated; then, based on the difference corresponding to each photovoltaic module and the state of charge of the energy storage unit, the energy storage unit is controlled to perform or not perform power compensation on its corresponding photovoltaic module; power compensation includes charging compensation and discharging compensation. If not, then each energy storage unit will be controlled to restore its power, exit operation, or remain inactive based on its state of charge. After control is completed, update the compensation capability indicator bit and repeat the above process.

[0006] In some implementations, determining whether to enter the power compensation mode includes: performing a logical AND operation between the power equalization enable signal and the compensation capability indicator bit; if the result is 1, then the power compensation mode is entered; if the result is 0, then the power compensation mode is not entered.

[0007] In some implementations, each energy storage unit is controlled to perform power compensation for its corresponding photovoltaic module, including: If the difference corresponding to a certain photovoltaic module is greater than 0, and the state of charge of the energy storage unit corresponding to the photovoltaic module is greater than the lower threshold, then the energy storage unit is controlled to charge using the difference as the charging power; if the difference corresponding to a certain photovoltaic module is less than 0, and the state of charge of the energy storage unit corresponding to the photovoltaic module is less than the upper threshold, then the energy storage unit is controlled to discharge using the absolute value of the difference as the discharge power. Among them, the lower threshold is lower than the upper threshold.

[0008] Furthermore, when the difference corresponding to a certain photovoltaic module is greater than 0, if the state of charge of the corresponding energy storage unit is not greater than the lower threshold, or greater than the lower threshold but not greater than the intermediate threshold, then the energy storage unit is controlled not to perform power compensation; when the difference corresponding to a certain photovoltaic module is less than 0, if the state of charge of the corresponding energy storage unit is not less than the upper threshold, or less than the upper threshold but not less than the intermediate threshold, then the energy storage unit is controlled not to perform power compensation. The intermediate threshold is between the lower threshold and the upper threshold.

[0009] In some implementations, each energy storage unit is controlled to restore its charge based on its state of charge, including: If the state of charge of a certain energy storage unit is greater than the upper threshold, the energy storage unit is controlled to operate in discharge mode; if the state of charge of a certain energy storage unit is less than the lower threshold, the energy storage unit is controlled to operate in charging mode; if the state of charge of a certain energy storage unit is between the lower threshold and the upper threshold, the energy storage unit is controlled to exit operation.

[0010] Furthermore, before controlling each energy storage unit to restore its power, it is first determined whether the state of charge of all energy storage units is equal to the preset value. If so, all energy storage units are controlled to exit operation and the compensation capacity indicator is set to the effective state. If not, each energy storage unit is controlled to restore its power.

[0011] Furthermore, in discharge mode, the discharge power of the energy storage unit is set according to the preset energy recovery rate requirement and does not exceed the maximum allowable operating power of the energy storage unit, so as not to cause overmodulation of the cascaded H-bridge converter; in charging mode, the charging power of the energy storage unit is set according to the preset energy recovery rate requirement and does not exceed the maximum allowable operating power of the energy storage unit, so as not to cause overmodulation of the cascaded H-bridge converter.

[0012] In some implementations, after entering the power compensation mode and completing power compensation, the compensation capability indicator is set to an active state; after not entering the power compensation mode and completing power recovery, the compensation capability indicator is set to an inactive state. The initial state of the compensation capability indicator bit is the active state.

[0013] In some implementations, power compensation is used to make the AC output power of each power module of the cascaded H-bridge converter more consistent, and the total output power of the single-phase photovoltaic-storage hybrid system is not affected by power compensation.

[0014] This invention also provides a power optimization allocation system for a single-phase photovoltaic-storage hybrid system, used to implement the aforementioned power optimization allocation method for the single-phase photovoltaic-storage hybrid system, comprising a data acquisition module, a mode determination module, and a state update and loop module; wherein: The data acquisition module is used to: acquire the real-time power generation of each photovoltaic module and receive the power balancing enable signal; The mode determination module is used to determine whether to enter the power compensation mode based on the power equalization enable signal and the compensation capability indicator bit of the energy storage unit. If so, the average power is calculated based on the real-time power generation of each photovoltaic module, and the difference between the real-time power generation of each photovoltaic module and the average power is calculated; then, based on the difference corresponding to each photovoltaic module and the state of charge of the energy storage unit, the energy storage unit is controlled to perform or not perform power compensation on its corresponding photovoltaic module; power compensation includes charging compensation and discharging compensation. If not, then each energy storage unit will be controlled to restore its power, exit operation, or remain inactive based on its state of charge. The status update and loop module is used to update the compensation capability indicator bit after control is completed and repeat the above process.

[0015] Compared with the prior art, the power optimization allocation method and system of the single-phase photovoltaic-storage hybrid system of the present invention has the following beneficial effects: This invention acquires the power generation of each photovoltaic module in real time and calculates the difference between it and the average value. Using this difference as the basis for regulation, it controls each energy storage unit to selectively charge and compensate for the excess power of modules with excessively high power absorption or discharge and compensate for the power deficit of modules with excessively low power absorption. This ensures that the equivalent output power on the AC side of each module is consistent, thereby maintaining the modulation ratio of each module within the linear modulation range. Simultaneously, this invention uses a dual judgment mechanism of power balance enable signal and compensation capability indicator bit to divide the operating mode of the energy storage unit into power compensation and power recovery stages. It determines whether the energy storage unit has compensation capability and which compensation method to use based on its own state of charge. In principle, this ensures that the energy storage unit will not endanger its own operational safety due to over-discharge or over-charge, and that the power regulation capability of the energy storage unit is actively applied to the entire operating process of the system, rather than merely serving as a passive remedial measure after over-modulation occurs.

[0016] Furthermore, after each round of control, this invention updates the compensation capability indicator bit and executes it cyclically, forming a closed-loop control that continuously tracks photovoltaic power fluctuations and dynamically adjusts the energy storage compensation strategy. This adaptively responds to sudden changes in sunlight and load variations, ensuring the energy storage unit always operates under a safe charging state and maximizes its power supplementation capabilities. This invention optimizes proactive prevention of power quality issues at the grid connection point and the safety factor of the energy storage unit itself, improving the system's stability and efficiency under different operating conditions to a certain extent. Attached Figure Description

[0017] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a flowchart illustrating the power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the topology of a single-phase photovoltaic-storage hybrid system in an embodiment of the power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to the present invention. Figure 3 The diagram shows the bidirectional DC-DC converter topology of the energy storage module in the embodiment of the power optimization allocation method for a single-phase photovoltaic-energy storage hybrid system according to the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0022] It should be noted that the apparatus and methods disclosed in the embodiments herein can also be implemented in other ways. The apparatus embodiments described above are merely illustrative; for example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments herein. In this regard, each block in a flowchart or block diagram may represent a module, program, or part of code containing one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system to perform the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0023] In addition, the functional modules in the various embodiments of this article can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0024] How to use the power of the energy storage system as a power supplement to the photovoltaic power generation system, so as to achieve consistent AC output power of each power module of the cascaded H-bridge converter and ensure optimal power quality output at the grid connection point.

[0025] Based on this, the present invention provides a power optimization allocation method for a single-phase photovoltaic-energy storage hybrid system, wherein the single-phase photovoltaic-energy storage hybrid system includes a cascaded H-bridge converter and an energy storage unit, and the method includes the following steps: Obtain the real-time power generation of each photovoltaic module and receive the power balancing enable signal; Based on the power balancing enable signal and the compensation capability indicator bit of the energy storage unit, determine whether to enter the power compensation mode; If so, the average power is calculated based on the real-time power generation of each photovoltaic module, and the difference between the real-time power generation of each photovoltaic module and the average power is calculated; then, based on the difference corresponding to each photovoltaic module and the state of charge of the energy storage unit, the energy storage unit is controlled to perform or not perform power compensation on its corresponding photovoltaic module; power compensation includes charging compensation and discharging compensation. If not, then each energy storage unit will be controlled to restore its power, exit operation, or remain inactive based on its state of charge. After control is completed, update the compensation capability indicator bit and repeat the above process.

[0026] In this invention, a power optimization allocation method for a single-phase photovoltaic-storage hybrid system utilizes the power of the energy storage system as a power supplement to the photovoltaic power generation system. This method enables consistent AC output power across all power modules of the cascaded H-bridge converter, ensuring optimal power quality at the grid connection point and relatively simplifying the complexity of the power balancing control algorithm. Furthermore, this invention allows for relatively autonomous control of the state of charge of the energy storage unit, thus ensuring a certain level of operational safety.

[0027] In some embodiments, the present invention performs a logical AND operation between the power equalization enable signal and the compensation capability indicator bit. If the result is 1, the power compensation mode is entered; if the result is 0, the power compensation mode is not entered. Performing a logical AND operation between the power equalization enable signal and the compensation capability indicator bit improves the real-time performance of mode switching.

[0028] Furthermore, the basic conditions for the energy storage unit to participate in power compensation in this invention are as follows: For components with power above the average value, the state of charge (SOC) of the corresponding energy storage unit must be above the lower threshold before charging compensation can be performed to ensure that the energy storage unit has a safe space to receive electrical energy; for components with power below the average value, the SOC of the corresponding energy storage unit must be below the upper threshold before discharging compensation can be performed to ensure that the energy storage unit has a usable capacity to release electrical energy. This invention also adds a secondary screening mechanism based on an intermediate threshold. When the SOC of the energy storage unit is in the lower range between the lower threshold and the intermediate threshold, its electrical energy is relatively scarce. If it is still charged for compensation, it will further approach the over-discharge protection boundary. At the same time, the limited electrical energy absorbed by the energy storage unit at this time is also difficult to provide effective support for subsequent discharge demand. When the SOC of the energy storage unit is in the higher range between the intermediate threshold and the upper threshold, its electrical energy is relatively abundant. If it is still discharged for compensation, it will further approach the overcharge protection boundary. In this state, the marginal contribution of the energy storage unit's discharge behavior to the system power balance has been reduced. By introducing an intermediate threshold as a safety margin in the compensation access conditions, the energy storage unit can exit power compensation when its state of charge is in an extreme range.

[0029] Furthermore, this invention controls the energy storage units to operate in discharge mode, charging mode, or exit operation based on their state of charge (SOC) range, thus forming hysteresis control. Before entering the power recovery process, it first determines whether the SOC of all energy storage units is equal to a preset value. If so, it indicates that the system has reached an ideal power balance state, and all energy storage units are controlled to exit operation, with the compensation capability indicator set to an effective state to avoid unnecessary charge-discharge cycles. If not, differentiated power recovery control is performed for each energy storage unit, giving the power recovery process a clear target orientation. In power recovery mode, the power value of the energy storage unit can be flexibly set according to the preset power recovery rate requirement, while the maximum allowable operating power of the energy storage unit is used as the upper limit constraint, enabling the system to adaptively adjust the recovery rate according to the urgency of the operating conditions, preventing damage to the energy storage units due to power surges.

[0030] This invention sets the compensation capability indicator to an active state after entering power compensation mode and completing power compensation; and sets it to an inactive state after not entering power compensation mode and completing power recovery. The initial state of the compensation capability indicator is active. Based on this, the system is guaranteed to enter power compensation mode by default in the first control cycle after power-on, allowing the energy storage unit to participate in power balancing control from the beginning of system operation. Setting the indicator to inactive after power recovery effectively prevents the energy storage unit from being re-scheduled into compensation mode before its power has been fully recovered, ensuring sufficient intermittent periods for power recovery.

[0031] Furthermore, the power compensation of this invention is used to make the AC output power of each power module of the cascaded H-bridge converter tend to be consistent, and the total output power of the single-phase photovoltaic-storage hybrid system is not affected by the power compensation. The compensation object is the relative power deviation between each power module rather than the increase or decrease of the total system power. The energy storage unit transfers the power of the surplus module to the deficit module, rather than absorbing or injecting additional active power from the grid side, so as to independently complete the internal power balance without changing the agreed exchange power between the system and the grid. On the other hand, the constant total output power enables this invention to be well compatible with the power dispatch instructions issued by the upper-level energy management system, without requiring the upper-level system to perform additional coordination or compensation for this method.

[0032] like Figure 1 As shown, in some embodiments, the power optimization allocation method for a single-phase photovoltaic-storage hybrid system of the present invention is carried out according to the following steps: The first stage includes system initialization and overall logic judgment.

[0033] Step 1: After the process starts, control all photovoltaic units to operate in maximum power point tracking mode, enabling each photovoltaic module to output the maximum power under the current operating conditions. Real-time data collection and calculation of the power generation of each photovoltaic module are performed. ( This is the power module serial number. Initialize the energy storage unit compensation capability indicator bit. This indicates that the energy storage unit initially possesses power balancing compensation capabilities.

[0034] Step 2: Receive the power balancing enable signal from the control system. For the enable signal Compensation capability indicator bit Perform a logical AND operation to obtain the overall control variable: ; for variables Perform branching decisions: 1) If If the power balancing function is enabled and the energy storage has compensation capability, then the energy storage unit enters the power compensation stage; mode A to mode E; 2) If Power balancing is not enabled, or energy storage does not have compensation capabilities; enter the energy storage unit's self-recovery phase; mode F to mode I.

[0035] The second stage includes the power compensation stage of the energy storage units from mode A to mode E. By regulating the charging and discharging of the energy storage units, the power deviation of each photovoltaic module is smoothed out, and the AC output power of each module in the cascaded H-bridge is made consistent.

[0036] Step 3: Calculate the average power generation of all photovoltaic modules. This serves as the benchmark value for power equalization. The calculation of the... The difference between the power generation of each photovoltaic module and the average value .

[0037] Step 4: If the deviation is zero, then it is mode A.

[0038] Triggering conditions: The current photovoltaic module power output is consistent with the average power output. Action to execute: Control the energy storage unit. Exit system operation; no adjustment is required. Flag update: Maintain compensation capability indicator. Process flow: After completing this round of adjustment, return to step 2 to enter the next round of loop judgment.

[0039] Step 5: Positive Deviation Branch ( When the power deviation is positive, it is further determined whether the state of charge of the corresponding energy storage unit exceeds the upper limit. : 1) If If so, then it is mode B.

[0040] Action performed: Control the energy storage unit Operating in discharge mode, discharge power set to Flag update: Keep Process flow: Return to step 2 to enter the next loop.

[0041] 2) If Then it is mode C.

[0042] Action: Control all energy storage units to exit system operation and terminate power compensation. Flag update: Set compensation capacity indicator bit. Process flow: Return to step 2 to enter the next loop.

[0043] Step 6: Negative Deviation Branch ( When the power deviation is negative, it is further determined whether the state of charge of the corresponding energy storage unit is below the lower limit. : 1) If If , then it is mode D.

[0044] Action performed: Control the energy storage unit Operating in charging mode, charging power set to Flag update: Keep Process flow: Return to step 2 to enter the next loop.

[0045] 2) If Then it is mode E.

[0046] Action: Control all energy storage units to exit system operation and terminate power compensation. Flag update: Set compensation capacity indicator bit. Process flow: Return to step 2 to enter the next loop.

[0047] The three stages include the energy storage unit's self-recovery stage (mode F to mode I), which operates when the energy storage does not participate in power balancing, autonomously adjusting the state of charge of each energy storage unit to the target value, ensuring the safety of energy storage operation and subsequent compensation capabilities.

[0048] Step 7: Determine the state of the power equalization enable signal EN: 1) If Then it is mode F.

[0049] Action executed: Control all energy storage units to shut down the system. Flow: Return to step 2 to enter the next main loop.

[0050] 2) If The power balancing function is enabled, but the energy storage does not yet have the ability to compensate, and the system enters the single energy storage unit SOC self-adjustment process.

[0051] Step 8, regarding the first Each energy storage unit, in target state of charge Adjustments are made based on the benchmark: 1) If Then it is mode G.

[0052] Action performed: Control the energy storage unit Exit system operation.

[0053] 2) If Further compare their sizes: 3) If Then it is mode H.

[0054] Action performed: Control the energy storage unit It operates in discharge mode; the discharge power can be set according to the power recovery rate requirements, and is constrained to not exceed the maximum operating power of the energy storage unit and not cause overmodulation of the cascaded H-bridge converter.

[0055] 4) If If , then it is mode I.

[0056] Action performed: Control the energy storage unit It operates in charging mode; the charging power can be set according to the power recovery rate requirements, and is constrained to not exceed the maximum operating power of the energy storage unit and not cause overmodulation of the cascaded H-bridge converter.

[0057] Step 9: After completing the mode assignment of all energy storage units, determine whether the state of charge of all energy storage units has reached the target value. : 1) If all energy storage units meet the requirements Power self-recovery complete, compensation capability indicator set. Once the power balance compensation capability of the energy storage is restored, return to step 2 to enter the next main cycle.

[0058] 2) If not all target values ​​are reached: continue to operate in the current self-recovery mode, return to step 8 to continue the cyclic adjustment until all energy storage SOCs meet the target.

[0059] It should be noted that, as Figure 2 The diagram shown illustrates the topology of the single-phase photovoltaic-storage hybrid system of this invention. The hybrid system employs a single-phase cascaded H-bridge converter topology with a parallel bidirectional DC-DC converter structure, consisting of n power modules. Each power module comprises n photovoltaic modules and n energy storage modules. The photovoltaic modules consist of an H-bridge topology and photovoltaic modules, with the H-bridge topology directly connected to the photovoltaic modules. The energy storage modules consist of a bidirectional DC-DC converter and battery cells, with one side of the bidirectional DC-DC converter connected to the photovoltaic modules and the other side connected to the battery cells. The AC terminals of the n photovoltaic modules are connected in series and then connected to a filter inductor for grid connection.

[0060] Figure 2 The topology forms the architectural basis for implementing the method of the present invention. Since each photovoltaic module has an independent and identical energy storage module connected in parallel on the DC side, and each energy storage module is independently connected to the DC bus of the corresponding photovoltaic module through its own bidirectional DC converter, the method of the present invention can control the switching transistors of each energy storage module to independently perform charging or discharging operations according to the real-time power deviation of each photovoltaic module, so that the AC output power of each power module tends to be consistent.

[0061] like Figure 3 The diagram shown is a topology diagram of a single-phase photovoltaic-storage hybrid system in an embodiment of the present invention. Figure 3 topology and Figure 2 The main structure is the same, the difference being that a schematic diagram of the filter inductor L connected to the AC grid Vg is provided, and the voltage and current variables of each key node in the energy storage module are marked, including: the output currents IPV1~IPVn of the photovoltaic module, the DC bus voltages VPV1~VPVn of the photovoltaic module, the inductor currents IB1~IBn of the energy storage module, and the battery cell voltages VB1~VBn. The bidirectional DC-DC converter adopts a bidirectional Buck-Boost converter based on a half-bridge topology.

[0062] The charging power command or discharging power command of each energy storage module determined by the method of this invention is ultimately controlled by... Figure 3The sixth switch in each power module shown Or the fifth switching transistor ( Power tracking is achieved by adjusting the duty cycle and switching timing of the switch.

[0063] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Anyone skilled in the art can readily implement the present invention according to the description and above. Any modifications, alterations, or equivalent variations made using the technical content disclosed above are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A power optimization allocation method for a single-phase photovoltaic-energy storage hybrid system, wherein the single-phase photovoltaic-energy storage hybrid system comprises a cascaded H-bridge converter and an energy storage unit, characterized in that, The method includes the following steps: Obtain the real-time power generation of each photovoltaic module and receive the power balancing enable signal; Based on the power balancing enable signal and the compensation capability indicator bit of the energy storage unit, determine whether to enter the power compensation mode; If so, the average power is calculated based on the real-time power generation of each photovoltaic module, and the difference between the real-time power generation of each photovoltaic module and the average power is calculated; then, based on the difference corresponding to each photovoltaic module and the state of charge of the energy storage unit, the energy storage unit is controlled to perform or not perform power compensation on its corresponding photovoltaic module; power compensation includes charging compensation and discharging compensation. If not, then each energy storage unit will be controlled to restore its power, exit operation, or remain inactive based on its state of charge. After control is completed, update the compensation capability indicator bit and repeat the above process.

2. The power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to claim 1, characterized in that, Determining whether to enter power compensation mode includes: performing a logical AND operation between the power equalization enable signal and the compensation capability indicator bit. If the result is 1, then power compensation mode is entered; if the result is 0, then power compensation mode is not entered.

3. The power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to claim 1, characterized in that, Each energy storage unit is individually controlled to perform power compensation for its corresponding photovoltaic module, including: If the difference corresponding to a certain photovoltaic module is greater than 0, and the state of charge of the energy storage unit corresponding to the photovoltaic module is greater than the lower threshold, then the energy storage unit is controlled to charge using the difference as the charging power; if the difference corresponding to a certain photovoltaic module is less than 0, and the state of charge of the energy storage unit corresponding to the photovoltaic module is less than the upper threshold, then the energy storage unit is controlled to discharge using the absolute value of the difference as the discharge power. Among them, the lower threshold is lower than the upper threshold.

4. The power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to claim 3, characterized in that, When the difference corresponding to a certain photovoltaic module is greater than 0, if the state of charge of the corresponding energy storage unit is not greater than the lower threshold, or greater than the lower threshold but not greater than the middle threshold, then the energy storage unit is controlled not to perform power compensation; when the difference corresponding to a certain photovoltaic module is less than 0, if the state of charge of the corresponding energy storage unit is not less than the upper threshold, or less than the upper threshold but not less than the middle threshold, then the energy storage unit is controlled not to perform power compensation. The intermediate threshold is between the lower threshold and the upper threshold.

5. The power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to claim 1, characterized in that, The energy storage units are controlled to restore their charge based on their state of charge, including: If the state of charge of a certain energy storage unit is greater than the upper threshold, the energy storage unit is controlled to operate in discharge mode; if the state of charge of a certain energy storage unit is less than the lower threshold, the energy storage unit is controlled to operate in charging mode; if the state of charge of a certain energy storage unit is between the lower threshold and the upper threshold, the energy storage unit is controlled to exit operation.

6. The power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to claim 5, characterized in that, Before controlling each energy storage unit to restore power, first determine whether the state of charge of all energy storage units is equal to the preset value. If so, control all energy storage units to exit operation and set the compensation capacity indicator to the effective state. If not, control each energy storage unit to restore power separately.

7. The power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to claim 5, characterized in that, In discharge mode, the discharge power of the energy storage unit is set according to the preset energy recovery rate requirement and does not exceed the maximum allowable operating power of the energy storage unit, thus preventing overmodulation of the cascaded H-bridge converter; in charging mode, the charging power of the energy storage unit is set according to the preset energy recovery rate requirement and does not exceed the maximum allowable operating power of the energy storage unit, thus preventing overmodulation of the cascaded H-bridge converter.

8. The power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to claim 1, characterized in that, After entering power compensation mode and completing power compensation, the compensation capability indicator will be set to an active state; if power compensation mode is not entered and power recovery is not completed, the compensation capability indicator will be set to an inactive state. The initial state of the compensation capability indicator bit is the active state.

9. The power optimization allocation method for a single-phase photovoltaic-storage hybrid system according to claim 1, characterized in that, Power compensation is used to make the AC output power of each power module of the cascaded H-bridge converter more consistent, and the total output power of the single-phase photovoltaic-storage hybrid system is not affected by power compensation.

10. A power optimization allocation system for a single-phase photovoltaic-storage hybrid system, used to implement the power optimization allocation method for the single-phase photovoltaic-storage hybrid system according to any one of claims 1-9, characterized in that, It includes a data acquisition module, a pattern determination module, and a state update and loop module; among which: The data acquisition module is used to: acquire the real-time power generation of each photovoltaic module and receive the power balancing enable signal; The mode determination module is used to determine whether to enter the power compensation mode based on the power equalization enable signal and the compensation capability indicator bit of the energy storage unit. If so, the average power is calculated based on the real-time power generation of each photovoltaic module, and the difference between the real-time power generation of each photovoltaic module and the average power is calculated; then, based on the difference corresponding to each photovoltaic module and the state of charge of the energy storage unit, the energy storage unit is controlled to perform or not perform power compensation on its corresponding photovoltaic module; power compensation includes charging compensation and discharging compensation. If not, then each energy storage unit will be controlled to restore its power, exit operation, or remain inactive based on its state of charge. The status update and loop module is used to update the compensation capability indicator bit after control is completed and repeat the above process.

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