Optical energy storage and charging method, system and controller

Abstract

This application discloses a photovoltaic-storage-charging energy dispatching method, system, and controller, relating to the field of energy dispatching technology. The method includes collecting the power output of photovoltaic (PV) modules, the load power of charging pile groups, and the state of charge (SOC) of the energy storage system. It calculates the power difference between the load power of the charging pile groups and the power output of the PV modules. It obtains current grid electricity price information and grid dispatching instructions. Based on the power difference, the SOC of the energy storage system, the grid electricity price information, and the grid dispatching instructions, a preset hierarchical control strategy is introduced to generate charging and discharging control instructions. According to the charging and discharging control instructions, the charging / discharging of the energy storage system is controlled. Thus, this application can sequentially achieve safety protection, charging guarantee, and economic optimization functions based on the preset hierarchical control strategy. It can respond to grid dispatching instructions based on the hierarchical control strategy, thereby obtaining additional compensation benefits from the grid, which improves the system's operational economy.

Description

Technical Field

[0001] This application relates to the field of energy dispatching technology, and in particular to a photovoltaic energy dispatching method, system and controller. Background Technology

[0002] Against the backdrop of green energy conservation, distributed energy systems centered on photovoltaic power generation, electrochemical energy storage, and electric vehicle charging facilities are accelerating their integration and development. Integrated photovoltaic-energy storage-charging systems, as a comprehensive energy solution combining green power generation, flexible energy storage, and intelligent charging, can not only absorb renewable energy locally and reduce energy costs, but also effectively mitigate the impact of large-scale, disorderly electric vehicle charging on the power distribution network. Therefore, they demonstrate enormous application potential and promotional value in scenarios such as industrial and commercial parks and public parking lots.

[0003] However, most existing systems simply supply photovoltaic power directly to charging stations. While some systems incorporate energy storage units to implement simple peak-shaving and valley-filling strategies, such as charging during off-peak hours, they generally lack the ability to respond to grid dispatch instructions and cannot fully utilize photovoltaic power resources. This makes it difficult for the system to achieve an optimal balance between ensuring a good user charging experience and pursuing operational economics, ultimately resulting in high overall system costs.

[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main purpose of this application is to provide a photovoltaic-storage-charging energy dispatching method, which aims to address the problem that existing systems, due to their lack of responsiveness to grid dispatching commands, struggle to achieve an effective balance between ensuring user charging experience and improving operational economy, resulting in high overall system costs.

[0006] To achieve the above objectives, the photovoltaic energy storage and charging scheduling method proposed in this application includes: Collect data on the power generation of photovoltaic power generation modules, the load power of charging pile groups, and the state of charge of energy storage systems; Calculate the power difference between the load power of the charging pile group and the power generation power of the photovoltaic power generation modules; Obtain current grid electricity price time information and grid dispatch instructions; Based on the power difference, the state of charge of the energy storage system, the grid electricity price time information, and the grid dispatch instructions, a preset hierarchical control strategy is introduced to generate charging and discharging control instructions. The charging / discharging of the energy storage system is controlled according to the charging / discharging control command; The hierarchical control strategy includes: The first control strategy executed in the first order is used to limit the charging / discharging of the energy storage system according to the state of charge of the energy storage system in order to ensure the safety of the energy storage system. The second control strategy, executed in the second sequence, controls the energy storage system to discharge when the power difference is greater than zero to meet the power demand of the charging pile group. The third control strategy, executed in the third order, is used to control the charging / discharging of the energy storage system based on the power difference, grid electricity price time information, and grid dispatch instructions when the power difference is less than or equal to zero.

[0007] In one embodiment, the photovoltaic power generation module, the energy storage system, and the charging pile group are connected to the same common AC bus through their respective corresponding converter components, so that the energy generated by the photovoltaic power generation module is preferentially used by the charging pile group on the common AC bus, and the excess energy is stored by the energy storage system or fed to the grid through the grid connection point. The first control strategy includes: When the state of charge of the energy storage system is lower than the first safety threshold, the energy storage system is prohibited from discharging. When the state of charge of the energy storage system is higher than the second safety threshold, charging of the energy storage system is prohibited. The second control strategy includes: If the power difference is greater than zero, the energy storage system is controlled to adjust the discharge power of the energy storage system to the charging pile group according to the power difference, so as to meet the power demand of the charging pile group. The third control strategy includes: If the power difference is less than or equal to zero, the charging / discharging of the energy storage system is controlled according to the power difference, grid electricity price time information and grid dispatch instructions to participate in grid ancillary services and earn subsidies. If the power difference is less than or equal to zero and no grid dispatch instruction is received from the grid, the energy storage system is controlled to charge until the power difference is not less than zero and / or the state of charge of the energy storage system reaches the second safety threshold.

[0008] In one embodiment, the grid dispatching instructions include peak-shaving instructions and frequency regulation instructions; the step of controlling the charging / discharging of the energy storage system according to the grid dispatching instructions to participate in grid ancillary services and earn subsidies includes: If a peak-shaving command is received from the power grid, the energy storage system is controlled to discharge during the peak-shaving period indicated by the command. If a frequency regulation command is received from the power grid, the energy storage system is controlled to discharge to provide active power support when the power grid frequency is lower than the rated value; and the energy storage system is controlled to charge to absorb excess power when the power grid frequency is higher than the rated value.

[0009] In one embodiment, controlling the energy storage system to discharge during the peak-shaving period indicated by the peak-shaving command in response to the peak-shaving command includes: Obtain the peak-shaving power requirement of the peak-shaving command; Based on the power difference and the maximum allowable discharge power of the energy storage system, determine the total surplus power that can be supplied to the grid at present; When the total surplus power is not less than the peak-shaving power demand, the energy storage system is controlled to discharge so that the difference between the energy storage discharge power and the power difference is equal to the peak-shaving power demand. When the total surplus power is less than the peak-shaving power demand, the energy storage system is controlled to discharge at the maximum allowable discharge power.

[0010] In one embodiment, the first control strategy further includes: Monitor the voltage of the common AC bus; Without triggering the prohibition of discharging and charging of the energy storage system, when the voltage of the common AC bus exceeds the preset safety range, the energy storage system is controlled to regulate the voltage through charging / discharging until it returns to the preset safety range.

[0011] In one embodiment, before generating charge / discharge control commands, the method further includes: Obtain the photovoltaic power generation prediction power sequence and the charging pile group load prediction power sequence corresponding to multiple moments within a preset time period, divided by preset time intervals; Based on the photovoltaic power generation prediction power sequence and the charging pile group load prediction power sequence, the net load power difference sequence for the future preset period is calculated item by item in time order, where each item represents the difference between the load prediction power and the power generation prediction power at the corresponding time. Based on the net load power difference sequence, all positive values ​​are identified, and the product of each positive value and its corresponding time interval is accumulated to obtain the cumulative energy deficit for the future preset period. Based on the cumulative energy deficit, a reserve value for energy storage capacity is set to ensure the power supply of the charging pile group; Based on the premise that the state of charge of the energy storage system is not lower than the reserved value of the energy storage capacity after responding to the grid dispatch command, a charging and discharging control command is generated.

[0012] In one embodiment, the preset time period is no more than 2 hours, and the preset time interval is no more than 5 minutes.

[0013] This application also proposes a controller configured to perform the photovoltaic energy storage and charging scheduling method described above.

[0014] This application also proposes a photovoltaic energy storage and charging scheduling system, including: Public AC busbar; A grid connection point is used to connect the common AC bus to the power grid; A photovoltaic power generation module includes a photovoltaic array and a photovoltaic inverter. The photovoltaic power generation module is connected to the common AC bus via the photovoltaic inverter. An energy storage system includes an energy storage battery and a bidirectional energy storage converter, wherein the energy storage battery is connected to the common AC bus via the bidirectional energy storage converter; A charging pile group includes one or more AC charging piles or DC charging piles, wherein the input terminal of the AC charging pile is directly connected to the common AC bus, and the DC charging pile is connected to the common AC bus through a built-in rectifier unit. The photovoltaic energy storage and charging scheduling system also includes the controller described above, which is communicatively connected to the photovoltaic inverter, the bidirectional energy storage converter, and the charging pile group.

[0015] In one embodiment, the controller is configured to communicate with the photovoltaic inverter and bidirectional energy storage converter via the Modbus protocol and / or the IEC 61850 protocol, and to communicate with the charging pile group via the OCPP protocol.

[0016] This application's technical solution adopts a photovoltaic-storage-charging energy dispatching method, including: Step S10, collecting the power generation of photovoltaic power generation modules, the load power of charging pile groups, and the state of charge (SOC) of the energy storage system. Step S20, calculating the power difference between the load power of the charging pile group and the power generation of the photovoltaic power generation modules. Step S30, obtaining the current grid electricity price time period information and grid dispatch instructions. Step S40, based on the power difference, the SOC of the energy storage system, the grid electricity price time period information, and the grid dispatch instructions, introducing a preset hierarchical control strategy to generate charging and discharging control instructions; wherein, the hierarchical control strategy includes: a first control strategy executed in a first order, used to limit the charging / discharging of the energy storage system according to the SOC of the energy storage system to ensure the safety of the energy storage system; a second control strategy executed in a second order, used to control the discharging of the energy storage system to meet the electricity demand of the charging pile group when the power difference is greater than zero; and a third control strategy executed in a third order, used to control the charging / discharging of the energy storage system according to the power difference, the grid electricity price time period information, and the grid dispatch instructions when the power difference is less than or equal to zero. Step S50: The charging / discharging of the energy storage system is controlled according to the charging / discharging control command. Thus, this application can respond to grid dispatch commands while ensuring the safety protection of the energy storage system and the charging guarantee of the charging pile group, thereby obtaining additional compensation benefits from the grid. Compared with existing technologies, this application can improve the system's operational economy without sacrificing the user's charging experience. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating an embodiment of the photovoltaic-storage-charging energy scheduling method of this application. Figure 2 This is a flowchart illustrating Embodiment 2 of the photovoltaic-storage-charging energy scheduling method of this application. Figure 3 This is a flowchart illustrating Embodiment 3 of the photovoltaic-storage-charging energy scheduling method of this application; Figure 4 This is a schematic diagram of a structure provided for an embodiment of the photovoltaic energy storage and charging scheduling system of this application.

[0019] The purpose, features, and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0022] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0023] Most existing systems simply supply power directly to charging stations via photovoltaic (PV) electricity. While some systems incorporate energy storage units to implement simple peak-shaving and valley-filling strategies, such as charging during off-peak hours, they generally lack the ability to respond to grid dispatch instructions and cannot fully utilize PV power resources. This makes it difficult for the system to achieve an optimal balance between ensuring a good user charging experience and pursuing operational economics, ultimately resulting in high overall system costs.

[0024] This application proposes a method for scheduling photovoltaic energy storage and charging power.

[0025] Please see Figure 1 In one embodiment of this application, the optical energy storage and charging scheduling method includes steps S10 to S50: Step S10: Collect the power generation of the photovoltaic power generation module, the load power of the charging pile group, and the state of charge of the energy storage system.

[0026] It should be noted that the power output of photovoltaic (PV) modules refers to the actual active power output of the PV array under current sunlight and temperature conditions. The load power of a charging pile group refers to the total active power consumed by all operating charging piles. The state of charge (SOC) of an energy storage system represents the percentage of its rated capacity remaining in the energy storage battery. In this step, accurately obtaining PV output, charging demand, and available energy storage capacity is crucial for subsequent power balancing and strategy decisions.

[0027] It should be noted that this method is applied to a photovoltaic-storage-charging energy scheduling system. Please refer to [link / reference]. Figure 4 The system includes photovoltaic power generation modules, charging pile groups, energy storage systems, and controllers. The controllers are communicatively connected to the photovoltaic power generation modules, charging pile groups, and energy storage systems to control their operation.

[0028] Step S20: Calculate the power difference between the load power of the charging pile group and the power generation power of the photovoltaic power generation module.

[0029] It should be noted that this power difference reflects the energy supply and demand relationship within the system. If the power difference is positive, it indicates that there is a power shortage; if the power difference is negative, it indicates a power generation surplus.

[0030] Step S30: Obtain the current grid electricity price time period information and grid dispatch instructions.

[0031] It should be noted that the grid electricity price period information refers to the current electricity price period, such as peak, flat, or valley periods (e.g., 0.3 yuan / kWh during valley periods and 1.2 yuan / kWh during peak periods). Grid dispatch instructions are issued by the grid dispatch center, including instructions for peak shaving and frequency regulation, requiring user-side resources to participate in grid regulation. This step involves obtaining the current grid electricity price period information and grid dispatch instructions to ensure the system can respond promptly to electricity price incentives and grid regulation needs, thereby seizing the operational window for low-cost electricity use and value-added services.

[0032] Step S40: Based on the power difference, the state of charge of the energy storage system, the grid electricity price time information, and the grid dispatch instructions, a preset hierarchical control strategy is introduced to generate charging and discharging control instructions; wherein, the hierarchical control strategy includes: The first control strategy executed in the first order is used to limit the charging / discharging of the energy storage system according to the state of charge of the energy storage system in order to ensure the safety of the energy storage system. The second control strategy, executed in the second sequence, is used to control the energy storage system to discharge when the power difference is greater than zero to meet the power demand of the charging pile group. The third control strategy, executed in the third order, is used to control the charging / discharging of the energy storage system based on the power difference, grid electricity price time information, and grid dispatch instructions when the power difference is less than or equal to zero.

[0033] It should be noted that the hierarchical control strategy is a decision-making mechanism with nested priorities. It first ensures equipment safety, then meets the user's power needs, and finally pursues maximum profit.

[0034] In this step, the controller's inputs include the power difference reflecting the local source-load balance, the state of charge (SOC) characterizing the energy storage's available regulation capability, grid electricity price information reflecting economic signals, and grid dispatch instructions representing external regulation needs. Based on these inputs, the controller executes a pre-defined hierarchical control strategy, namely, executing the first, second, and third control strategies sequentially according to priority. The first control strategy is used for the safety protection of the energy storage system, such as prohibiting discharge when the SOC is below a first safety threshold (e.g., 5%) and prohibiting charging when it is above a second safety threshold (e.g., 100%), preventing over-discharge or over-charge of the energy storage system. The second control strategy is executed based on the first control strategy to meet the electricity demand of the charging pile group. Within the safe charging and discharging limits of the energy storage system, and when the power difference is greater than zero (i.e., insufficient photovoltaic output), the energy storage system is controlled to discharge to supplement the grid gap. For example, in scenarios where photovoltaic output is insufficient, peak electricity prices are in effect, and there are no grid dispatch instructions (power difference +80kW, energy storage system SOC 60%), the energy storage system is controlled to discharge at 80kW, ensuring a good user experience. The third control strategy is executed based on the first and second control strategies and is used to participate in grid ancillary services and earn subsidies. For example, when photovoltaic power generation is high, peak electricity prices are in effect, and a grid peak-shaving instruction is received (e.g., peak-shaving power is 150kW, duration is 1 hour), if the current energy storage system SOC is ≥60%, higher than the first safety threshold, and the power difference is -80W, then the energy storage system is controlled to discharge continuously at 70kW for 1 hour or continuously discharge to a preset energy storage capacity reserve (e.g., 20%). This preset energy storage capacity reserve is used to ensure the electricity demand of the charging pile group within a preset future time period.

[0035] Step S50: Control the charging / discharging of the energy storage system according to the charging / discharging control command.

[0036] It should be noted that the energy storage system includes energy storage batteries and a bidirectional energy storage converter. The charging or discharging power of the energy storage batteries can be controlled by adjusting the power setpoint of the bidirectional energy storage converter.

[0037] It should be noted that photovoltaic power generation is intermittent and fluctuating, while the electricity load of charging pile groups is random, concentrated, and characterized by instantaneous high power, making it difficult to naturally match the two in terms of time. Without effective scheduling, not only will photovoltaic energy be wasted, but sudden load surges may also overload the grid transformers, while failing to fully utilize the economic benefits brought by peak-valley electricity price differences. This solution introduces a hierarchical control strategy. First, the state of charge of the energy storage system is used as a safety boundary to ensure the equipment's lifespan. Second, when photovoltaic power supply is insufficient, the energy storage is prioritized for discharge to smooth out load peaks. Finally, during periods of photovoltaic surplus or low electricity prices, the charging / discharging of the energy storage is intelligently decided based on grid dispatch instructions. This not only improves the renewable energy absorption rate but also achieves peak shaving and valley filling and economical operation, effectively solving the scheduling challenges caused by the high impact and high uncertainty of charging pile groups.

[0038] In this embodiment, a hierarchical control strategy, executed in priority order—namely, the first, second, and third control strategies—is employed to achieve energy mobilization that simultaneously protects the energy storage system, ensures charging capacity for the charging pile network, and optimizes economic efficiency. While ensuring the safe operation of the energy storage system and fully meeting user charging needs, the system dynamically adjusts the charging and discharging behavior of the energy storage system by combining grid price signals and grid dispatch instructions. It actively participates in grid ancillary services (such as peak shaving and valley filling, frequency regulation), thereby obtaining additional compensation from the grid. Compared to existing technologies, this embodiment improves the operational economy of the photovoltaic-storage-charging energy dispatching system.

[0039] Please see Figure 2 In one embodiment of this application, the photovoltaic power generation module, the energy storage system, and the charging pile group are connected to the same common AC bus through their respective corresponding converter components, so that the power generated by the photovoltaic power generation module is preferentially used by the charging pile group on the common AC bus, and the excess energy is stored by the energy storage system or fed to the grid through the grid connection point.

[0040] It should be noted that the controller can continuously calculate the power difference. If the power difference is negative and the energy storage system is close to full charge, it can actively limit the output power of the photovoltaic inverter to avoid excessive grid voltage fluctuations.

[0041] The first control strategy in step S40 includes steps S41 to S42: Step S41: When the state of charge of the energy storage system is lower than the first safety threshold, the energy storage system is prohibited from discharging.

[0042] It should be noted that the first safety threshold is a lower limit protection value set to prevent over-discharge of the battery, for example, it can be set to 5%.

[0043] Step S42: When the state of charge of the energy storage system is higher than the second safety threshold, charging of the energy storage system is prohibited.

[0044] It should be noted that the second safety threshold is greater than the first safety threshold. It is an upper limit protection value set to prevent battery overcharging, for example, it can be set to 100%.

[0045] The second control strategy includes step S43: If the power difference is greater than zero, the control energy storage system will adjust the discharge power of the energy storage system to the charging pile group according to the power difference in order to meet the power demand of the charging pile group.

[0046] In this embodiment, when the power difference is greater than zero, it indicates insufficient photovoltaic output and a power shortage. Furthermore, the power shortage is filled by discharging energy through the energy storage system, while simultaneously avoiding purchasing electricity from the grid at high prices.

[0047] It should be noted that if the energy storage system's state of charge is below the first safety threshold, discharging the energy storage system is prohibited. If the power difference is greater than zero, the load power of the charging pile group can be reduced accordingly (when the charging urgency is low) or the system can directly draw power from the grid (when the charging urgency is high), depending on the user's charging urgency. There are no restrictions here.

[0048] The third control strategy includes steps S44-S45: Step S44: If the power difference is less than or equal to zero, then based on the power difference, grid electricity price time information and grid dispatch instructions, control the charging / discharging of the energy storage system to participate in grid ancillary services and earn subsidies.

[0049] For example, when the power difference is zero, the energy storage system can be charged during off-peak hours and discharged during peak hours based on grid electricity price information. When the power difference is less than or equal to zero, if a grid dispatch command (such as a peak-shaving command or a frequency regulation command) is received, the energy storage system can be controlled to charge / discharge according to the instructions of the grid dispatch command.

[0050] In one embodiment, step S44 includes steps S441 to S442: Step S441: If a peak-shaving command is received from the power grid, then in response to the peak-shaving command, the energy storage system is controlled to discharge during the peak-shaving period indicated by the peak-shaving command.

[0051] Step S441 may include steps S4411 to S4414: Step S4411: Obtain the peak power requirement of the peak shaving command; Step S4412: Determine the total surplus power that can be supplied to the grid at present based on the power difference and the maximum allowable discharge power of the energy storage system; Step S4413: When the total surplus power is not less than the peak shaving power demand, control the energy storage system to discharge so that the difference between the energy storage discharge power and the power difference is equal to the peak shaving power demand. Step S4414: When the total surplus power is less than the peak power demand, control the energy storage system to discharge at the maximum allowable discharge power.

[0052] In this implementation, during peak electricity price periods (such as 10:00–15:00 and 18:00–22:00), if a peak-shaving instruction is received from the power grid (requiring the feed of a specified power to the power grid), the controller needs to calculate the maximum surplus power that can be transmitted externally (i.e., the feed-in surplus power) and compare it with the dispatch demand: if the feed-in surplus power is greater than or equal to the peak-shaving power demand, then power is fed on demand; if the feed-in surplus power is less than the peak-shaving power demand, then it is not executed to avoid affecting the local load or exceeding the limit operation.

[0053] For example, during the peak-shaving period from 14:00 to 14:30, the grid issues a continuous power supply command of 150kW. At this time, the photovoltaic power generation is 200kW, the charging pile load is 120kW, and the energy storage is at 85% charge, with a maximum discharge capacity of 100kW. The controller performs a judgment once every preset control cycle (e.g., every minute): First, it calculates the current surplus power that can be fed, i.e., 200kW (photovoltaic) + 100kW (maximum discharge of energy storage) - 120kW (load) = 180kW. Since 180kW is greater than the dispatch requirement of 150kW, the system determines that it has the ability to respond. Then, it generates charging and discharging commands: 120kW of photovoltaic output is prioritized to supply the charging piles, and the remaining 80kW is directly fed into the grid; at the same time, it controls the energy storage converter to discharge at a power of 70kW to supplement the power supply gap, so that the total power supply is stabilized at 150kW. Throughout the 14:00–14:30 period, the system continuously operates according to this strategy, cumulatively feeding 45 kWh (150 kW × 0.5 h) of energy into the grid, thereby obtaining corresponding peak-shaving compensation. Conversely, if the charging pile load suddenly increases to 180 kW within a certain control cycle, the surplus power available for feeding will drop to 200 + 100 - 180 = 120 kW, which is lower than the dispatch demand of 150 kW. In this way, the controller controls the energy storage system to discharge at a maximum power of 100 kW. In this way, a flexible and reliable response to grid peak-shaving commands is achieved.

[0054] In step S442, if a frequency regulation command is received from the power grid, then in response to the frequency regulation command, when the power grid frequency is lower than the rated value, the energy storage system is controlled to discharge to provide active power support; when the power grid frequency is higher than the rated value, the energy storage system is controlled to charge to absorb excess power.

[0055] It should be noted that the photovoltaic-storage-charging energy dispatching system can achieve second-level dynamic response to grid frequency fluctuations based on real-time monitoring of the grid connection point frequency. For example, under normal operating conditions, the photovoltaic power generation is 150kW, the charging pile load is 150kW, the energy storage state of charge is 80%, and the bidirectional converter is in standby or fine-tuning mode. When the grid frequency drops sharply to 49.7 Hz (below the rated 50 Hz) due to disturbances such as large unit tripping, the controller identifies the frequency deviation within hundreds of milliseconds through the built-in measurement module, the smart meter at the grid connection point, or the energy storage converter, and automatically triggers energy storage discharge, for example, injecting active power into the common bus with a power of +30kW. At this time, the total output of the photovoltaic-storage-charging energy dispatching system becomes 150kW photovoltaic + 30kW energy storage = 180kW, of which 150kW continues to support the charging pile load, and the remaining 30kW is fed into the grid, providing 30kW more supporting power than before the disturbance. This rapid active power injection helps to slow down the frequency drop rate. Once the grid frequency returns to the normal range (e.g., ≥49.95 Hz), the frequency regulation response automatically exits, controlling the energy storage system to stop discharging. During frequency regulation, a frequency tolerance range can be set, within which the system does not respond to frequency changes to avoid frequent charging and discharging of energy storage due to minor daily fluctuations in the grid. When the frequency deviation exceeds the frequency tolerance range, the photovoltaic-storage-charging energy dispatching system adjusts the active power output according to a preset linear proportional relationship. In this way, the integral of the power change and its duration during the regulation process can be measured and used to calculate the frequency regulation compensation benefits, thereby improving economic efficiency while supporting grid security.

[0056] Step S45: If the power difference is less than or equal to zero and no grid dispatch instruction is received from the grid, the energy storage system is controlled to charge until the power difference is not less than zero and / or the state of charge of the energy storage system reaches the second safety threshold.

[0057] For example, at 10:00 AM on a certain day (assuming the local off-peak electricity price period continues until this time), the photovoltaic power generation is 150kW, the charging pile group load is 120kW, and the power difference is -30kW, indicating a surplus in photovoltaic output; at the same time, the energy storage system's state of charge is 70%, below the second safety threshold of 100%. Under these conditions, the 30kW photovoltaic surplus is used to charge the energy storage system. If, after a period of time, the photovoltaic power generation drops to 120kW while the charging pile group load remains at 120kW, or the energy storage system's state of charge rises to 100%, then charging of the energy storage system is stopped.

[0058] Thus, this embodiment can earn grid subsidies in response to grid dispatch commands such as peak shaving and frequency regulation commands, and can use surplus photovoltaic energy for charging or charge under off-peak electricity prices, which reduces the operating cost of the photovoltaic-storage-charging energy dispatch system.

[0059] It should be noted that the scheduling of existing systems is susceptible to prediction errors, which may result in the depletion of energy storage in the event of a sudden energy shortage.

[0060] Please see Figure 3 In one embodiment of this application, before generating the charge / discharge control command in step S40, the optical energy storage and charging scheduling method further includes steps S4001 to S4005: Step S4001: Obtain the photovoltaic power generation prediction power sequence and the charging pile group load prediction power sequence corresponding to multiple moments divided by a preset time interval within a future preset time period.

[0061] In this step, the preset time period is no more than 2 hours, and the preset time interval is no more than 5 minutes.

[0062] Step S4002: Based on the photovoltaic power generation prediction power sequence and the charging pile group load prediction power sequence, calculate the net load power difference sequence for the future preset period item by item in chronological order, where each item represents the difference between the load prediction power and the power generation prediction power at the corresponding time.

[0063] Step S4003: Based on the net load power difference sequence, identify all positive values ​​and accumulate the product of each positive value and its corresponding time interval to obtain the cumulative energy deficit for the future preset period.

[0064] Step S4004: Based on the cumulative energy deficit, set a reserve value for energy storage capacity to ensure power supply for the charging pile group.

[0065] Step S4005: Based on the premise that the state of charge of the energy storage system is not lower than the reserved value of the energy storage capacity after responding to the grid dispatch command, a charging and discharging control command is generated.

[0066] It should be noted that both the photovoltaic power generation forecast power series and the charging pile group load forecast power series can be generated by the forecast module integrated inside the controller. This module supports parallel processing and differentiated modeling of multi-source time series data.

[0067] It should be noted that the controller can calculate the required discharge amount through grid dispatch commands, and combine this with historical photovoltaic power generation and charging pile group electricity consumption to calculate the actual required discharge amount of the energy storage system. It also calculates the difference between the current total dischargeable capacity of the energy storage system and the reserved energy storage capacity. If the required discharge amount is greater than this difference, the controller will discharge according to this difference or not respond to the grid dispatch command, and generate corresponding charge / discharge commands. If the required discharge amount is not greater than this difference, the controller will respond normally to the grid dispatch command.

[0068] The photovoltaic power generation prediction sequence can be generated based on an LSTM (Long Short-Term Memory) neural network. At the current time (e.g., 09:00), the controller first collects historical operating data from the past two hours (from 07:00 to 09:00). The input data includes three core components: first, measured photovoltaic power data, with 24 historical power points acquired at 5-minute intervals; second, synchronized meteorological data, including irradiance, ambient temperature, and humidity; and third, time features, such as the current hour, minute, and month information. In the data preprocessing stage, the controller normalizes these raw data to eliminate dimensional differences between different physical quantities and reconstructs the data into a three-dimensional array format suitable for model input. For example, data from the past 60 minutes (12 time steps) is selected as an input window, forming a tensor containing four features: power, irradiance, temperature, and humidity, which serves as the real-time input to the model. In the algorithm processing stage, the controller loads a pre-trained three-layer LSTM neural network model. The input layer receives tensor data of shape (12, 4), representing 12 time steps and 4 features. The first LSTM layer captures short-term fluctuations in photovoltaic power, such as sudden changes in irradiance caused by rapid cloud movement. The second LSTM layer further extracts dependencies over a longer time range to understand the trend of weather changes. A dropout layer is placed between the two LSTM layers to prevent overfitting and improve generalization ability. After the cell state is calculated through the gating mechanism (forget gate, input gate, output gate) of the LSTM hidden layer, the data is fed into the fully connected layer, ultimately outputting the power prediction value for the first 5 minutes in the future (i.e., 09:05). In the data output stage, a rolling prediction strategy can be used to generate a complete future sequence. First, the model predicts the power at 09:05 based on the current 09:00 window data. Then, the time window is slid forward, incorporating the predicted 09:05 data (or after correction with historical data) into the input sequence to predict the power at 09:10. This process is repeated until all predictions for the next 24 time points (i.e., the next 2 hours) are completed. Ultimately, the controller can generate a photovoltaic power generation prediction sequence containing 24 values, such as [Ppv(09:05),Ppv(09:10),...,Ppv(11:00)], in kW.

[0069] The power sequence for predicting the load of a charging station cluster can be obtained based on Monte Carlo simulation. For example, for a charging station with 20 DC fast charging piles, the controller initiates the load prediction process at the current time (e.g., 5:00 PM on Friday). The input data is mainly divided into two categories: first, historical statistical data, including the average arrival rate of vehicles (e.g., 15 vehicles per hour), average charging time, and average charging capacity during the same time period over the past 30 days; second, real-time characteristics, such as whether it is currently the evening peak period, Friday, and whether there is a queue of vehicles. These data are used as the basic parameters for constructing a probabilistic model to reflect the randomness of user behavior. The algorithm processing can be carried out based on Monte Carlo simulation and the M / G / k queuing theory model. First, based on the historical arrival rate, the number of vehicles that may arrive within a 5-minute interval in the next 2 hours is generated by random sampling. Then, for each simulated arriving vehicle, the system randomly samples its initial SOC and target SOC based on a normal distribution to calculate the required charging capacity. Then, based on the power characteristic curve of the charging pile (e.g., charging at a constant power of 120kW when the SOC is below 50%, and gradually decreasing power after it is above 50%), the charging power and duration of the vehicle are calculated. Finally, the power of vehicles charging in the same time slice in all simulation scenarios is summed to obtain the total load at that moment. In the data output stage, to ensure the robustness of the prediction, a preset number of simulations (e.g., 500) can be run, and the median result is selected as the final output. Finally, the controller obtains a charging pile group load prediction power sequence containing 24 values, such as [Pload(17:05), Pload(17:10), ..., Pload(19:00)], in kW. This sequence, along with the photovoltaic power generation prediction sequence, is input to the controller to calculate the net load and formulate energy storage reservation strategies.

[0070] In this embodiment, a soft constraint is achieved on the discharge behavior of the energy storage system in response to grid dispatch commands through forward-looking net load analysis and energy deficit calculation. Compared with the existing technology that makes decisions based solely on the current state, this embodiment performs preventative dispatch based on future predicted scenarios and mandates that the state of charge of the energy storage battery after responding to grid dispatch commands is not lower than the reserved value of the energy storage capacity, in order to avoid potential power shortages in the future.

[0071] This application also proposes a controller configured to execute the photovoltaic-storage-charging energy scheduling method described above. Compared with the prior art, the beneficial effects of the controller provided in this application are the same as those of the photovoltaic-storage-charging energy scheduling method provided in the above embodiments, and other technical features in the controller are the same as those disclosed in the methods of the above embodiments, and will not be repeated here.

[0072] Please see Figure 4This application also proposes a photovoltaic energy storage and charging scheduling system, which includes: Public AC busbar; The grid connection point is used to connect the public AC busbar to the power grid; Photovoltaic power generation components, including photovoltaic arrays and photovoltaic inverters, are connected to the common AC bus via photovoltaic inverters; The energy storage system includes an energy storage battery and a bidirectional energy storage converter, wherein the energy storage battery is connected to the common AC bus via the bidirectional energy storage converter; A charging pile group includes one or more AC charging piles or DC charging piles, wherein the input terminal of the AC charging pile is directly connected to the common AC bus, and the DC charging pile is connected to the common AC bus through a built-in rectifier unit. The photovoltaic-storage-charging energy dispatching system also includes the controller described above, which is communicatively connected to the photovoltaic inverter, the bidirectional energy storage converter, and the charging pile group.

[0073] Since the controller adopts all the technical solutions of all the above embodiments, the photovoltaic energy storage and charging scheduling system has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0074] It should be noted that the grid connection point can be equipped with smart meters to record power supply and consumption to the grid. The controller can communicate with the smart meters to obtain their recorded data.

[0075] In one embodiment, the controller is configured to communicate with the photovoltaic inverter and the bidirectional energy storage converter via the Modbus protocol and / or the IEC 61850 protocol, and to communicate with the charging pile group via the OCPP protocol.

[0076] It should be noted that the Modbus protocol is a serial communication protocol used by the controller to read the basic operating status of the photovoltaic inverter and the bidirectional energy storage converter and issue control commands; the IEC 61850 protocol is an international standard communication protocol in the field of power system automation, which supports advanced interoperability between devices based on a unified information model and is suitable for standardized information exchange between the controller and the photovoltaic inverter and the bidirectional energy storage converter; OCPP (Open ChargePoint Protocol) is an open charging pile communication protocol used by the controller to remotely monitor the charging pile group, control its start and stop, and manage charging transaction data.

[0077] The above description is merely an exemplary embodiment of this application and does not limit the patent scope of this application. Any equivalent structural transformations made based on the technical concept of this application and the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this application.

Claims

1. A method for scheduling photovoltaic energy storage and charging, characterized in that, include: Collect data on the power generation of photovoltaic power generation modules, the load power of charging pile groups, and the state of charge of energy storage systems; Calculate the power difference between the load power of the charging pile group and the power generation power of the photovoltaic power generation modules; Obtain current grid electricity price time information and grid dispatch instructions; Based on the power difference, the state of charge of the energy storage system, the grid electricity price time information, and the grid dispatch instructions, a preset hierarchical control strategy is introduced to generate charging and discharging control instructions. The charging / discharging of the energy storage system is controlled according to the charging / discharging control command; The hierarchical control strategy includes: The first control strategy executed in the first order is used to limit the charging / discharging of the energy storage system according to the state of charge of the energy storage system in order to ensure the safety of the energy storage system. The second control strategy, executed in the second sequence, controls the energy storage system to discharge when the power difference is greater than zero to meet the power demand of the charging pile group. The third control strategy, executed in the third order, is used to control the charging / discharging of the energy storage system based on the power difference, grid electricity price time information, and grid dispatch instructions when the power difference is less than or equal to zero.

2. The method as described in claim 1, characterized in that, Photovoltaic power generation modules, energy storage systems and charging pile groups are connected to the same common AC bus through their respective corresponding converter components, so that the energy generated by the photovoltaic power generation modules is preferentially used by the charging pile groups on the common AC bus, and the excess energy is stored by the energy storage system or fed to the grid through the grid connection point. The first control strategy includes: When the state of charge of the energy storage system is lower than the first safety threshold, the energy storage system is prohibited from discharging. When the state of charge of the energy storage system is higher than the second safety threshold, charging of the energy storage system is prohibited. The second control strategy includes: If the power difference is greater than zero, the energy storage system is controlled to adjust the discharge power of the energy storage system to the charging pile group according to the power difference, so as to meet the power demand of the charging pile group. The third control strategy includes: If the power difference is less than or equal to zero, the charging / discharging of the energy storage system is controlled according to the power difference, grid electricity price time information and grid dispatch instructions to participate in grid ancillary services and earn subsidies. If the power difference is less than or equal to zero and no grid dispatch instruction is received from the grid, the energy storage system is controlled to charge until the power difference is not less than zero and / or the state of charge of the energy storage system reaches the second safety threshold.

3. The method as described in claim 2, characterized in that, The grid dispatch instructions include peak shaving instructions and frequency regulation instructions; the step of controlling the charging / discharging of the energy storage system according to the grid dispatch instructions to participate in grid ancillary services and earn subsidies includes: If a peak-shaving command is received from the power grid, the energy storage system is controlled to discharge during the peak-shaving period indicated by the command. If a frequency regulation command is received from the power grid, the energy storage system is controlled to discharge to provide active power support when the power grid frequency is lower than the rated value; and the energy storage system is controlled to charge to absorb excess power when the power grid frequency is higher than the rated value.

4. The method as described in claim 3, characterized in that, The step of controlling the energy storage system to discharge during the peak-shaving period indicated by the peak-shaving command in response to the peak-shaving command includes: Obtain the peak-shaving power requirement of the peak-shaving command; Based on the power difference and the maximum allowable discharge power of the energy storage system, determine the total surplus power that can be supplied to the grid at present; When the total surplus power is not less than the peak-shaving power demand, the energy storage system is controlled to discharge so that the difference between the energy storage discharge power and the power difference is equal to the peak-shaving power demand. When the total surplus power is less than the peak-shaving power demand, the energy storage system is controlled to discharge at the maximum allowable discharge power.

5. The method as described in claim 2, characterized in that, The first control strategy also includes: Monitor the voltage of the common AC bus; Without triggering the prohibition of discharging and charging of the energy storage system, when the voltage of the common AC bus exceeds the preset safety range, the energy storage system is controlled to regulate the voltage through charging / discharging until it returns to the preset safety range.

6. The method as described in claim 1, characterized in that, Before generating charge / discharge control commands, the method further includes: Obtain the photovoltaic power generation prediction power sequence and the charging pile group load prediction power sequence corresponding to multiple moments within a preset time period, divided by preset time intervals; Based on the photovoltaic power generation prediction power sequence and the charging pile group load prediction power sequence, the net load power difference sequence for the future preset period is calculated item by item in time order, where each item represents the difference between the load prediction power and the power generation prediction power at the corresponding time. Based on the net load power difference sequence, all positive values ​​are identified, and the product of each positive value and its corresponding time interval is accumulated to obtain the cumulative energy deficit for the future preset period. Based on the cumulative energy deficit, a reserve value for energy storage capacity is set to ensure the power supply of the charging pile group; Based on the premise that the state of charge of the energy storage system is not lower than the reserved value of the energy storage capacity after responding to the grid dispatch command, a charging and discharging control command is generated.

7. The method as described in claim 6, characterized in that, The preset time period is no more than 2 hours, and the preset time interval is no more than 5 minutes.

8. A controller, characterized in that, The controller is configured to perform the photovoltaic energy storage and charging scheduling method as described in any one of claims 1 to 7.

9. A photovoltaic energy storage and charging scheduling system, characterized in that, include: Public AC busbar; A grid connection point is used to connect the common AC bus to the power grid; A photovoltaic power generation module includes a photovoltaic array and a photovoltaic inverter. The photovoltaic power generation module is connected to the common AC bus via the photovoltaic inverter. An energy storage system includes an energy storage battery and a bidirectional energy storage converter, wherein the energy storage battery is connected to the common AC bus via the bidirectional energy storage converter; A charging pile group includes one or more AC charging piles or DC charging piles, wherein the input terminal of the AC charging pile is directly connected to the common AC bus, and the DC charging pile is connected to the common AC bus through a built-in rectifier unit. The photovoltaic energy storage and charging scheduling system also includes the controller as described in claim 8, which is communicatively connected to the photovoltaic inverter, the bidirectional energy storage converter, and the charging pile group.

10. The photovoltaic energy storage and charging scheduling system as described in claim 9, characterized in that, The controller is configured to communicate with the photovoltaic inverter and bidirectional energy storage converter via Modbus protocol and / or IEC 61850 protocol, and to communicate with the charging pile group via OCPP protocol.

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