Power supply system based on photovoltaic-energy storage-grid connection linkage

Abstract

The application discloses a power supply system based on photovoltaic-energy storage-grid connection linkage, and relates to the technical field of power grids. Photovoltaic power generation power, energy storage state of charge, power grid load and real-time electricity price data are acquired in a same frequency mode, a historical database is constructed, and power shortage characteristics are extracted from the historical database. A periodic power to-be-supplemented time interval is locked through clustering analysis. On this basis, the system calculates benefit evaluation values of each period in combination with power shortage and electricity price levels, divides the to-be-supplemented interval into two categories of an optimal category and a non-optimal category, and forms a time reference for differentiated regulation and control. An adaptive regulation end dynamically selects strategies such as energy storage alone compensation, photovoltaic auxiliary compensation or photovoltaic alone compensation according to the interval type to which the current time belongs and real-time photovoltaic output and energy storage state, and accurately calculates power compensation amount. Energy storage resources are preferentially called to cope with the shortage of high electricity price periods, and photovoltaic power is fully used to realize in-situ consumption in conventional periods, so that the economic benefit and power supply reliability are synergistically optimized.

Description

Technical Field

[0001] This invention belongs to the field of power grid technology, specifically relating to a power supply system based on photovoltaic-energy storage-grid connection. Background Technology

[0002] As the global energy structure accelerates its transformation towards clean and low-carbon energy, the organic linkage and synergistic optimization of distributed photovoltaic and energy storage devices with the public power grid has become an important development direction for improving energy efficiency and ensuring power supply quality.

[0003] In existing technologies, there is a general lack of systematic mining and periodic pattern extraction of historical operating data in the spatiotemporal identification dimension of power deficit. Traditional approaches often rely on real-time monitoring or simple threshold comparison to trigger responses, and the fragmented data processing methods make it impossible for the system to predict the high-incidence period of power deficit. The control decision is always in a passive follow-up state, making it difficult to achieve forward-looking planning. Secondly, in terms of the correlation between economic benefits and regulatory priorities, existing technologies almost never use real-time electricity prices as the core decision variable for power compensation strategies. The scheduling logic of traditional photovoltaic-storage grid-connected systems usually takes peak shaving and valley filling or smoothing power output as a single objective. This lack of economic consideration leads to energy storage adopting an indiscriminate discharge strategy during periods of low and high electricity prices. The peak-valley arbitrage space has not been fully explored, and the overall economic benefits of the system are far from optimal.

[0004] To address the aforementioned issues, this invention proposes a power supply system based on photovoltaic-energy storage-grid connection. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a power supply system based on photovoltaic-energy storage-grid linkage, which solves the problems of lack of time-based optimization for power compensation, lack of linkage between economic benefits and real-time electricity prices, and the extensive and rigid photovoltaic-energy storage regulation strategy in existing technologies.

[0006] The objective of this invention can be achieved through the following technical solutions: A power supply system based on photovoltaic-energy storage-grid connection, the system comprising: The deficit cycle identification terminal is associated with photovoltaic power generation arrays, energy storage devices and power grid, and collects photovoltaic power generation power, energy storage state of charge, power grid load power and real-time power grid price in the same frequency manner, forming a related data group stored in the historical database; By using the numerical relationship between the power grid load power and the power grid load power of different related data groups in the historical database during different acquisition cycles, the power supplementation time interval is locked, and the periodic power supplementation time interval Tz is further determined. In the optimal benefit interval, the difference between the grid load power and the grid load power within Tz is used in conjunction with the correlation between the real-time electricity price of the grid to lock in the optimal benefit time interval set Tg and the non-optimal benefit time interval set Tf. The adaptive control unit determines the current time (Tg or Tf) in real time, and generates a power compensation method and power compensation amount by combining the current photovoltaic power generation and energy storage state of charge, and performs differentiated prior power control.

[0007] As a further embodiment of the present invention, in the deficit cycle identification terminal, the photovoltaic power generation array, energy storage device and power grid are connected to this system through a system bus; The system also includes a pre-built historical database, which stores the photovoltaic power generation of the photovoltaic power generation array, the energy storage state of the energy storage device, and the grid load power and real-time grid electricity price of the grid, collected at the same preset collection frequency within the collection period. The time span of the collection period is from 0:00 to 24:00 every day.

[0008] As a further aspect of the present invention, the specific method by which the associated data group is stored in the historical database in the deficit period identification terminal is as follows: Determine any acquisition period, and denote the start time of this acquisition period as t1 and the end time as tj, where j is the total number of times within the acquisition period; Determine the photovoltaic power generation collected at j moments within the collection period, arrange them in chronological order, and denot them as the photovoltaic power generation sequence P=P1,P2,...,Pj; Similarly, determine the energy storage charge state sequence S=S1,S2,...,Sj, the grid load power sequence F=F1,F2,...,Fj, and the grid real-time electricity price sequence C=C1,C2,...,Cj; The photovoltaic power generation power sequence, energy storage state of charge sequence, grid load power sequence, and grid real-time electricity price sequence within the same acquisition period are combined and denoted as the associated data group G={P,S,F,C}, and stored in the historical database.

[0009] As a further aspect of the present invention, the specific method for locking the power compensation time interval in the deficit period identification terminal is as follows: Retrieve n related data groups that are closest to the current time from the historical database, denoted as G1, G2, ..., Gn, where n is a preset positive integer; Extract the associated data set G1 and parse the power grid load sequence F=F1,F2,...,Fj; Obtain the fixed grid load power, denoted as F. base ; Construct a two-dimensional coordinate system XY1 with the time line as the horizontal axis and the power value as the vertical axis; The power grid load sequence F=F1,F2,...,Fj is aligned with the horizontal and vertical axis scales and plotted as data points in XY1 to obtain n data points. The power grid load change curve WF is obtained by curve fitting. Draw a line through the vertical axis with the value F. base A straight line perpendicular to the vertical axis and parallel to the horizontal axis is denoted as the load power line L1; Obtain the power margin F preset by the operator. more Using F base -F more =F jud Calculate the maximum over-limit power F jud And the over-limit power line L2 is plotted in XY1 in the same way as L1; Determine the portion of the power load change curve WF located between the load power line L1 and the over-limit power line L2, and determine the start and end times of each portion on the horizontal axis. Summarize all times within the start and end times to form the power compensation time interval tz. Similarly, determine all power-to-be-compensated time intervals and denote them as the power-to-be-compensated time interval set {tz1,tz2,...,tzo} in chronological order, where o is the total number of power-to-be-compensated time intervals.

[0010] As a further aspect of the present invention, the specific method for determining the time interval Tz for the periodic power to be compensated in the deficit period identification terminal is as follows: Determine the set of power time intervals to be supplemented for all associated data groups in G1, G2, ..., Gn; Count the occurrence frequency of each moment in all time intervals of the power time interval set of n related data groups. Extract the moments whose occurrence frequency exceeds the operator's preset occurrence frequency threshold as periodic candidate moments, and arrange them in chronological order as periodic candidate moment sequence k1,k2,...,ku, where u is the total number of periodic candidate moments; Starting from the candidate time k1 of the period, it is determined sequentially whether the time difference between the current time and the next time is ≤ ΔT, where ΔT is a preset time difference threshold; Yes, the two moments are grouped into the same cluster; No, create a new cluster; Repeat the above steps until all candidate time periods have been traversed, resulting in several clusters; The earliest and latest times in all clusters are determined and the time intervals are summarized, all of which are denoted as the periodic power supplement time interval Tz. In order of time, all periodic power supplement time intervals are represented as Tz1, Tz2, ..., TzR, where R is the total number of periodic power supplement time intervals.

[0011] As a further aspect of the present invention, the specific method for locking the set of time intervals Tg for which the preferred benefits need to be supplemented in the benefit interval optimization end is as follows: Extract the time interval Tzr of arbitrary periodic power to be supplemented, where r is the counting index, 1≤r≤R; Determine the grid load power F(t) and real-time grid electricity price C(t) for all times within Tzr, and simultaneously calculate the power deficit ΔF(t) for all times, where ΔF(t) = F base -F(t), where (t) represents different times; The benefit evaluation value E(t) at each time point is calculated using E(t) = ΔF(t) × C(t), and the arithmetic mean E of the benefit evaluation values ​​at all times within the time interval Tzr where the periodic power needs to be supplemented is determined. avg ; The arithmetic mean E avg Compared with the preset benefit discrimination threshold E th Comparison; If E avg ≥E th The time interval Tzr for the periodic power to be supplemented is marked as the time interval for the optimal benefit to be supplemented, and then it is assigned to the set Tg for the optimal benefit to be supplemented in chronological order.

[0012] As a further aspect of the present invention, in the preferred end of the benefit interval, if the arithmetic mean E of the periodic power to be compensated time interval Tzr is... avg <E th The time interval Tzr for the periodic power to be supplemented is marked as the time interval for the non-optimal benefit to be supplemented, and is then assigned to the set Tf of the non-optimal benefit to be supplemented time intervals in chronological order.

[0013] As a further aspect of the present invention, the specific method for performing differentiated prior power regulation in the adaptive control terminal is as follows: Get the current time t in real time now Determine the current time t now The time interval type to which it belongs, if t now If ∈Tg, then obtain the current time t. now The power grid load F(t) now ), calculate the current power deficit ΔF(t) now )=max(F base -F(t now ),0); Get the current time t now Photovoltaic power generation P(t) now ) and energy storage state of charge (SOC(t) now ); Based on the rated capacity (SOC) of the energy storage device tot Preset minimum allowable state of charge (SOC) for energy storage min Given the control period Δt, calculate the maximum power P that the energy storage device can currently release. avi =min(P bm SOC(t) now )-SOC min )×SOC tot / Δt), where P bm This represents the maximum discharge power of the energy storage device. If P avi ≥ΔF(t now The power compensation method is determined to be energy storage-only compensation, and the power compensation amount is Q=ΔF(t). now It also sends a discharge power command Q to the energy storage converter. If P avi <ΔF(t) now The power compensation method is determined to be energy storage priority with photovoltaic auxiliary compensation, and the energy storage discharge power is P. avi The compensation power required by photovoltaics is ΔF(t) now )-P avi ; If the current photovoltaic power generation P(t) now )≥ΔF(t now )-P avi If the photovoltaic power supply is sufficient, the surplus will be provided; otherwise, the shortfall will be absorbed by the grid, and the power compensation will still be Q=ΔF(t).

[0014] As a further aspect of the present invention, in the adaptive control terminal, if t now If ∈Tf, then the following differential prior power regulation is performed, specifically including: Determine the current power deficit ΔF(t) now ) and photovoltaic power generation P(t now ) and energy storage state of charge (SOC(t) now ); If P(t) now )≥ΔF(t now The power compensation method is determined to be photovoltaic separate compensation, and the power compensation amount is Q=ΔF(t). now ); If P(t) now )<ΔF(t now The photovoltaic power is entirely used to compensate the power grid, with the remaining deficit ΔF(t) now )-P(t now (Provided by energy storage devices) Extract the maximum power P that the energy storage device can currently release. avi ; If Pavi ≥ΔF(t now )-P(t now The compensation method is determined to be joint compensation of photovoltaic energy storage, and the energy storage discharge power is ΔF(t). now )-P(t now The power compensation amount Q = ΔF(t) now ); If P avi <ΔF(t) now )-P(t now When the energy storage device discharges at full power and the remaining shortfall is absorbed by the grid, the power compensation amount remains Q=ΔF(t). now ).

[0015] The beneficial effects of this invention are: This invention achieves precise timing of power gaps through a deficit cycle identification end, avoiding blind scheduling, effectively reducing grid dependence and improving photovoltaic utilization; the benefit range optimization end intelligently distinguishes between high and low benefit periods based on the correlation between electricity price and load difference, providing economic guidance for subsequent regulation; the adaptive regulation end combines real-time photovoltaic output and energy storage status to perform differentiated prior power compensation, ensuring power supply reliability, maximizing the benefits brought by peak-valley electricity price difference, reducing energy storage cycle losses, improving the overall system operation economy and energy efficiency, and enhancing the collaborative interaction between the grid side and the user side. This invention constructs a multi-dimensional correlated data set including photovoltaic power, energy storage charge, load power, and electricity price, and performs clustering statistics based on the load overload pattern within historical cycles. This allows for the precise identification of periodically occurring power shortage time intervals. The core advantage lies in fully utilizing the repetitive characteristics of historical time-series data, combined with preset margin thresholds and time continuity judgments, to effectively filter out occasional fluctuations, improve the reliability and robustness of shortage period identification, and provide a stable and predictable time benchmark for subsequent energy storage scheduling, thereby optimizing the economy and security of power grid operation. This invention dynamically extracts real-time grid load and electricity price data within the periodic power deficit interval and simultaneously calculates the power deficit. Then, it uses the arithmetic mean of the benefit evaluation value as the core discrimination index and compares it with a preset threshold to achieve intelligent optimization and classification of the time interval to be supplemented. Its advantages are that it integrates the quantification of economic benefits into energy storage dispatch decision-making, avoiding the one-sidedness of relying solely on load or electricity price, and prioritizing the allocation of energy storage resources to high-benefit periods, effectively improving the system's operational economy and energy utilization efficiency. At the same time, by distinguishing non-optimal intervals, it provides a clear basis for subsequent differentiated dispatch strategies and enhances the system's adaptability to electricity price fluctuations. This invention fully explores the synergistic regulation potential of energy storage and photovoltaics, and prioritizes the use of low-cost, low-loss clean energy by matching grid deficits and equipment status in real time, thereby reducing dependence on the grid and curtailment rate. Its segmented decision-making mechanism can both ensure the safety boundary of energy storage charge and dynamically balance response speed and regulation accuracy. It avoids deep discharge of energy storage when the deficit is small and orderly allocates power tasks when the deficit is large, improving system economy and power supply reliability. At the same time, it reduces the pressure on grid frequency regulation and realizes smooth power compensation and optimal resource utilization at multiple time scales. Attached Figure Description

[0016] The invention will now be further described with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the system described in this invention; Figure 2 This is a schematic diagram of the implementation process of the system described in this invention. Detailed Implementation

[0018] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1 , Figure 2 As shown, this application provides a power supply system based on photovoltaic-energy storage-grid connection; As an embodiment 1 of this application, it specifically includes: The deficit cycle identification terminal is associated with photovoltaic power generation arrays, energy storage devices and power grid, and collects photovoltaic power generation power, energy storage state of charge, power grid load power and real-time power grid price in the same frequency manner, forming a related data group stored in the historical database; By using the numerical relationship between the power grid load power and the power grid load power of different related data groups in the historical database during different acquisition cycles, the power supplementation time interval is locked, and the periodic power supplementation time interval Tz is further determined. In the optimal benefit interval, the difference between the grid load power and the grid load power within Tz is used in conjunction with the correlation between the real-time electricity price of the grid to lock in the optimal benefit time interval set Tg and the non-optimal benefit time interval set Tf. The adaptive control unit determines the current time (Tg or Tf) in real time, and generates a power compensation method and power compensation amount by combining the current photovoltaic power generation and energy storage state of charge, and performs differentiated prior power control.

[0020] Example 2

[0021] This embodiment continues from embodiment 1, and through predictive identification and benefit assessment, achieves differentiated prior control of photovoltaics, energy storage, and the power grid. The system includes a deficit cycle identification terminal, a benefit range optimization terminal, and an adaptive control terminal, as detailed below: In this embodiment, the photovoltaic power generation array, energy storage device and power grid are connected to this system through a system bus, which is an Ethernet-based industrial data bus that follows the TCP / IP protocol.

[0022] The inverters of the photovoltaic power generation array, the converters of the energy storage device, and the smart meters at the grid connection point are all connected to the bus as slave stations. The main body of this system is an industrial embedded controller, which acts as the master station and collects data through the bus in a polling manner.

[0023] The deficit cycle identification terminal is configured to collect data in a synchronous manner, specifically as follows: By synchronizing the clock with the network time protocol server, the system ensures that the timestamps of all devices are consistent. The system sets a collection period from 00:00:00 to 23:59:59 every day. At the start of each minute at the same preset sampling frequency, the controller simultaneously sends read commands to the photovoltaic inverter, energy storage PCS, and smart grid meter to acquire and record the following data: Photovoltaic power generation, unit: kW; Energy storage state of charge (SOC), percentage form; Grid load power, unit: kW; and Real-time grid electricity price, unit: yuan / kWh.

[0024] The real-time electricity price of the power grid is obtained from the API interface provided by the power market trading platform.

[0025] The deficit cycle identification terminal integrates a pre-built historical database, which is a time series database used to efficiently store and query timestamped related data. Based on the collection cycle, the four types of data sequences acquired within a day are packaged into a related data group and stored in the historical database.

[0026] The deficit cycle identification module locks the time interval Tz for the cycle power to be supplemented based on historical data, and its logic is as follows: First, determine the composition of the associated data group. For a collection cycle from t1 (00:00) to tj (23:59), j is 1440, with a frequency of minutes.

[0027] The 1440 photovoltaic power generation data points collected were arranged in chronological order as a sequence P={P1,P2,...,P1440}; Similarly, the energy storage state of charge sequence S={S1,S2,...,S1440}, the grid load power sequence F={F1,F2,...,F1440}, and the grid real-time electricity price sequence C={C1,C2,...,C1440} are obtained. Combining these four sequences forms an associated data group G={P,S,F,C}.

[0028] Secondly, extract the n most recent related data groups from the current time, for example, n=10, denoted as G1, G2, ..., G10.

[0029] Taking G1 as an example, its grid load power sequence F is extracted from it. The system has a pre-stored fixed grid load power F. base This value is a constant demand value agreed upon in the regional power distribution agreement, such as F. base =500kW.

[0030] The system constructs a two-dimensional coordinate system XY1 with time as the horizontal axis and power as the vertical axis.

[0031] The 1440 data points in the power grid load sequence F are plotted in XY1, and a smooth power grid load change curve WF is formed by polynomial curve fitting. Then plot a line representing F on XY1. base The straight line is used as the load power line L1.

[0032] The operator presets a power margin F more For example, F more =20kW, then calculate the maximum over-limit power F jud =F base -F more =480kW.

[0033] Mapping F on XY1 jud The straight line is taken as the over-limit power line L2.

[0034] On the power load change curve WF, the segment of the curve located between the load power line L1 and the over-limit power line L2 means that the power load is lower than the agreed load power, but not lower than the threshold that triggers the penalty clause. This range is the ideal area for power deficit compensation.

[0035] Determine the start and end times of each such curve segment on the horizontal time axis. The set of all times between these two times constitutes a power-to-be-compensated time interval tz.

[0036] Traverse WF to identify all such intervals, and obtain the set of power time intervals to be supplemented for G1 {tz1,tz2,...,tzo}.

[0037] Finally, statistical analysis was performed on all tz of the 10 associated data sets G1 to G10 to determine Tz.

[0038] First, count the occurrences of each time point in all tz, set a threshold of 5 occurrences (half of n), extract the time points with an occurrence count greater than or equal to 5 as periodic candidate time points, and arrange them in chronological order as sequences k1, k2, ..., ku.

[0039] Next, the time difference threshold ΔT is set to 30 minutes. Starting from k1, the time difference between adjacent candidate times is judged to be less than or equal to 30 minutes. If yes, they are grouped into the same cluster; otherwise, a new cluster is created.

[0040] After the traversal is complete, several clusters are obtained. For each cluster, the earliest and latest times are taken to form a time interval.

[0041] The time interval mentioned is the periodic power supplementation time interval Tz.

[0042] Sort all Tz in chronological order, denoted as {Tz1,Tz2,...,TzR}.

[0043] For example, two stable replacement cycles may eventually be identified: Tz1 is from 09:30 to 11:00 daily, and Tz2 is from 18:00 to 20:30 daily.

[0044] The optimal benefit range is responsible for classifying Tz based on economic efficiency, as follows: Taking Tz1 (09:30-11:00) as an example, this interval contains 90 time points. The grid load power F(t) and real-time electricity price C(t) of these 90 time points are extracted.

[0045] For each time moment, calculate the power deficit ΔF(t) = F base -F(t).

[0046] Subsequently, the benefit evaluation value E(t) = ΔF(t) × C(t) at each time point is calculated. This value represents the economic benefit or the savings in demand electricity costs that can be achieved by compensating a unit of power at that time. The arithmetic mean E(t) of all times within Tz1 is then calculated. avg The operator presets a benefit judgment threshold E. th For example, E th =50 yuan / hour.

[0047] If E avg ≥E thThis means that power compensation during this period can generate an average benefit of more than 50 yuan per hour. Therefore, Tz1 is marked as the optimal benefit time interval to be compensated and is included in the set Tg.

[0048] Conversely, if Tz2's E avg If <Eth, then it is marked as a time interval with non-optimal benefits to be supplemented and included in the set Tf.

[0049] This embodiment accurately identifies valuable power ranges for filling gaps by introducing grid load power lines and power margins. Furthermore, through multi-period data clustering, random events are extracted into stable periodic events, providing clear time targets for subsequent a priori regulation and effectively improving the predictability and stability of the system response.

[0050] Example 3

[0051] This embodiment is based on embodiment 2, but the difference lies in the focus on explaining the specific process of differentiated prior power regulation performed by the adaptive control terminal when the system is currently within the set of time intervals Tg for optimal benefit supplementation. The device structure, data acquisition method, and interval identification logic are exactly the same as in embodiment 2.

[0052] First, conduct real-time assessment and strategy generation for the optimal benefit period; The adaptive control unit operates in a cyclic cycle with a control period of 1 second Δt. During a certain control cycle, the current time t is obtained in real time. now .

[0053] System determination t now ∈Tg. For example, t now The time is 10:00, which belongs to the identified preferred time period Tz1.

[0054] The first step is to make the first-level judgment: calculate the power deficit and obtain the system status.

[0055] Obtain the current grid load power F(t) through smart meters. now If the current power deficit is 460kW, then the current power deficit ΔF(t) is... now )=max(F base -F(t now ),0)=max(500kW-460kW,0)=40kW.

[0056] At the same time, read the current photovoltaic power generation P(t) now The power is 15kW, and the energy storage state of charge (SOC(t)) is 15kW. now The figure is 80%.

[0057] The key parameters of energy storage devices are: rated capacity and state of charge (SOC). tot=200kWh, preset minimum allowable state of charge (SOC) for energy storage min =20%, maximum discharge power P bm =100kW.

[0058] Next, a second level of judgment is made: assessing the independent compensation capability of energy storage.

[0059] Calculate the maximum continuous power P that the energy storage device can release within the current control period Δt (1 second). avi The formula is as follows: P avi =min(P bm ,(SOC(t now )-SOC min )×SOC tot / Δt)=(80%-20%)×200kWh / (1 / 3600)h=0.6×200kW×3600=432000kW.

[0060] 432000kW is much greater than P bm Therefore P avi =min(100kW,432000kW)=100kW.

[0061] This calculation shows that, without falling below the minimum state of charge, the energy storage device is capable of providing a continuous discharge power of 100kW.

[0062] Then, a third layer of judgment is made: determining the power compensation method and compensation amount.

[0063] Compare P avi =100kW and ΔF(t) now =40kW.

[0064] Because of P avi ≥ΔF(t now The system determines that the power compensation method is separate energy storage compensation. The power compensation amount is Q = ΔF(t). now =40kW.

[0065] The adaptive control terminal generates control commands and sends constant power discharge commands to the energy storage converter through the system bus, with a target power value of 40kW.

[0066] The energy storage device immediately discharged at a power of 40kW, flowing into the grid user-side bus, precisely compensating for the current power deficit, thus maintaining the power detected by the grid metering point at F. base nearby.

[0067] Next, the fourth level of judgment is executed (parallel to the third level of judgment). If P avi <ΔF(tnow): If at another time t now , ΔF(t now The power output is 120kW, while P avi It remains at 100kW.

[0068] At this time P avi <ΔF(t) now Since single energy storage cannot fully compensate for the power loss, the system determines that the power compensation method is energy storage priority with photovoltaic auxiliary compensation.

[0069] The energy storage discharge power command is 100kW = P avi The compensation power required by photovoltaics is ΔF(t) now )-P avi =20kW.

[0070] Compare the current photovoltaic power generation P(t) now ) and the demand value, if P(t) now If P(t) ≥ 20kW, then through the boost circuit and inverter, the photovoltaic system is instructed to output 20kW of power to the user-side bus; if P(t) ≥ 20kW, then the photovoltaic system is instructed to output 20kW of power to the user-side bus. now If the power output is less than 20kW, for example only 15kW, then the photovoltaic system will generate 15kW at full capacity, and the remaining 5kW will be naturally absorbed by the grid.

[0071] Ultimately, the total power compensation Q recorded by the system remains ΔF(t) now The value of 120kW is used for benefit calculation.

[0072] The technical advantage of this embodiment is that, during the identified high-efficiency periods, the lowest-cost energy storage resources are prioritized for precise compensation, maximizing savings on demand electricity costs. When energy storage capacity is insufficient, photovoltaic assistance is seamlessly introduced. The order of calling various energy sources and the precise power allocation calculation logic are clearly defined, ensuring the autonomy, economy, and reliability of the system during high-value periods.

[0073] Example 4

[0074] This embodiment is based on Embodiment 3, but differs in that it focuses on describing the specific process of another set of differentiated prior power control executed by the adaptive control terminal when the system is currently within the set of non-optimal benefit time intervals Tf: First, conservative economic regulation should be implemented during periods of non-optimal efficiency: The adaptive control unit continues to operate, and at a certain control cycle, it determines the current time t. now ∈Tf, for example, t now The time is 19:00, which is a non-preferred time period Tz2.

[0075] At this time, the sunlight is weak, and the photovoltaic power generation P(t)now (Lower, for example, 5kW.)

[0076] However, in order to maximize the consumption of clean energy, the regulation logic is completely different from that of the Tg period, and follows the conservative economic principle of prioritizing photovoltaic energy storage as a supplement.

[0077] First, make a judgment at the first level and calculate the deficit and photovoltaic capacity.

[0078] Obtain the current power deficit ΔF(t) now The photovoltaic power generation capacity is 60kW, and the photovoltaic power generation capacity is P(t). now The power output is 70kW.

[0079] Compare the two: P(t) now )≥ΔF(t now ).

[0080] At this point, photovoltaic power itself is sufficient to fill the gap.

[0081] The system determines the power compensation method as photovoltaic separate compensation, and the power compensation amount is Q=ΔF(t) now =60kW.

[0082] The adaptive control terminal commands the photovoltaic inverter to switch from maximum power point tracking mode to power limiting mode, precisely controlling the grid-connected power at 60kW, achieving accurate compensation of generating only what is needed, while the energy storage device remains in standby mode to save charge-discharge cycle life.

[0083] Then, the second layer of judgment is executed: energy storage assistance when photovoltaic power is insufficient.

[0084] Let another time t now , ΔF(t now The power output remains at 60kW, but P(t) now The power output drops to 20kW, at which point P(t) now )<ΔF(t now ).

[0085] The system first allocates all photovoltaic power to compensate the grid, i.e., the photovoltaic output is 20kW, and the remaining deficit is ΔF(t). now )-P(t now =40kW.

[0086] The system then calls upon the energy storage device to provide the remaining power, calculating the maximum power P that the stored energy can currently release. avi The power is 90kW, calculated in the same way as in Example 3.

[0087] Compare P avi =90kW and remaining deficit of 40kW: P avi ≥40kW.

[0088] Therefore, the system determines the compensation method as a combination of photovoltaic and energy storage compensation, with an energy storage discharge power command of 40kW.

[0089] Total power compensation Q = ΔF(t) now The total power capacity is 60kW, consisting of 20kW photovoltaic power and 40kW energy storage.

[0090] A third assessment is then made: even energy storage cannot completely cover all risks.

[0091] If the remaining deficit is 110kW, and P avi Only 70kW, at this time P avi <110kW.

[0092] The system then allows the energy storage device to operate at full power P. avi =70kW discharge, photovoltaic power generation at 20kW full capacity, the sum of the two is 90kW, which is still not enough to make up for the 110kW shortfall.

[0093] The remaining 20kW power deficit (110kW-90kW) will not be actively compensated and will be naturally absorbed by the grid. In this case, the total power compensation Q recorded by the system will still be calculated based on the demand deficit ΔF(t). now The power was recorded as 110kW to maintain a consistent economic accounting standard, but the actual physical compensation was only 90kW + 20kW = 110kW.

[0094] The technical advantage of this embodiment lies in distinguishing the control priority of different benefit periods. During non-optimal benefit periods, the system switches from energy storage priority to photovoltaic priority, making the most of photovoltaic energy with zero marginal cost. Only when photovoltaic capacity is insufficient will the energy storage asset with a limited cycle life be mobilized. In this way, while meeting the grid agreement requirements, the cycle loss cost of the energy storage system throughout its entire life cycle is minimized, and the long-term operating economy is optimized.

[0095] All data in the formulas described above have been calculated with dimensions removed. Furthermore, any content not described in detail in this specification is existing technology known to those skilled in the art.

[0096] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0097] It should be stated that all user data collected in this application was collected with the user's consent and authorization. Furthermore, the uses of user data are legal and compliant, and the use and processing of user data comply with the relevant laws, regulations, and standards of the relevant regions.

Claims

1. A power supply system based on photovoltaic-energy storage-grid connection, characterized in that, The system includes: The deficit cycle identification terminal is associated with photovoltaic power generation arrays, energy storage devices and power grid, and collects photovoltaic power generation power, energy storage state of charge, power grid load power and real-time power grid price in the same frequency manner, forming a related data group stored in the historical database; By using the numerical relationship between the power grid load power and the power grid load power of different related data groups in the historical database during different acquisition cycles, the power supplementation time interval is locked, and the periodic power supplementation time interval Tz is further determined. In the optimal benefit interval, the difference between the grid load power and the grid load power within Tz is used in conjunction with the correlation between the real-time electricity price of the grid to lock in the optimal benefit time interval set Tg and the non-optimal benefit time interval set Tf. The adaptive control unit determines the current time (Tg or Tf) in real time, and generates a power compensation method and power compensation amount by combining the current photovoltaic power generation and energy storage state of charge, and performs differentiated prior power control.

2. The system according to claim 1, characterized in that, In the deficit cycle identification terminal, the photovoltaic power generation array, energy storage device and power grid are connected to this system through the system bus; The system also includes a pre-built historical database, which stores the photovoltaic power generation of the photovoltaic power generation array, the energy storage state of the energy storage device, and the grid load power and real-time grid electricity price of the grid, collected at the same preset collection frequency within the collection period. The time span of the collection period is from 0:00 to 24:00 every day.

3. The system according to claim 2, characterized in that, In the aforementioned deficit period identification terminal, the specific method for constructing associated data groups and storing them in the historical database is as follows: Determine any acquisition period, and denote the start time of this acquisition period as t1 and the end time as tj, where j is the total number of times within the acquisition period; Determine the photovoltaic power generation collected at j moments within the collection period, arrange them in chronological order, and denot them as the photovoltaic power generation sequence P = P1, P2, ..., Pj; Similarly, determine the energy storage charge state sequence S=S1,S2,...,Sj, the grid load power sequence F=F1,F2,...,Fj, and the grid real-time electricity price sequence C=C1,C2,...,Cj; The photovoltaic power generation power sequence, energy storage state of charge sequence, grid load power sequence, and grid real-time electricity price sequence within the same acquisition period are combined and denoted as the associated data group G={P,S,F,C}, and stored in the historical database.

4. The system according to claim 3, characterized in that, The specific method for locking the power compensation time interval in the aforementioned deficit period identification terminal is as follows: Retrieve n related data groups that are closest to the current time from the historical database, denoted as G1, G2, ..., Gn, where n is a preset positive integer; Extract the associated data set G1 and parse the power grid load sequence F=F1,F2,...,Fj; Obtain the fixed grid load power, denoted as F. base ; Construct a two-dimensional coordinate system XY1 with the time line as the horizontal axis and the power value as the vertical axis; The power grid load sequence F=F1,F2,...,Fj is aligned with the horizontal and vertical axis scales and plotted as data points in XY1 to obtain n data points. The power grid load change curve WF is obtained by curve fitting. Draw a line through the vertical axis with the value F. base A straight line perpendicular to the vertical axis and parallel to the horizontal axis is denoted as the load power line L1; Obtain the power margin F preset by the operator. more Using F base -F more =F jud Calculate the maximum over-limit power F jud And the over-limit power line L2 is plotted in XY1 in the same way as L1; Determine the portion of the power load change curve WF located between the load power line L1 and the over-limit power line L2, and determine the start and end times of each portion on the horizontal axis. Summarize all times within the start and end times to form the power compensation time interval tz. Similarly, determine all power-to-be-compensated time intervals and denote them as the power-to-be-compensated time interval set {tz1,tz2,...,tzo} in chronological order, where o is the total number of power-to-be-compensated time intervals.

5. The system according to claim 4, characterized in that, In the aforementioned deficit period identification terminal, the specific method for determining the periodic power compensation time interval Tz is as follows: Determine the set of power time intervals to be supplemented for all associated data groups in G1, G2, ..., Gn; Count the occurrence frequency of each moment in all time intervals of the power time interval set of n related data groups. Extract the moments whose occurrence frequency exceeds the operator's preset occurrence frequency threshold as periodic candidate moments, and arrange them in chronological order as periodic candidate moment sequence k1,k2,...,ku, where u is the total number of periodic candidate moments; Starting from the candidate time k1 of the period, it is determined sequentially whether the time difference between the current time and the next time is ≤ ΔT, where ΔT is a preset time difference threshold; Yes, the two moments are grouped into the same cluster; No, create a new cluster; Repeat the above steps until all candidate time periods have been traversed, resulting in several clusters; The earliest and latest times in all clusters are determined and the time intervals are summarized, all of which are denoted as the periodic power supplement time interval Tz. In order of time, all periodic power supplement time intervals are represented as Tz1, Tz2, ..., TzR, where R is the total number of periodic power supplement time intervals.

6. The system according to claim 5, characterized in that, In the optimal benefit interval selection process, the specific method for locking the set of optimal benefit intervals Tg is as follows: Extract the time interval Tzr of arbitrary periodic power to be supplemented, where r is the counting index, 1≤r≤R; Determine the grid load power F(t) and real-time grid electricity price C(t) for all times within Tzr, and simultaneously calculate the power deficit ΔF(t) for all times, where ΔF(t) = F base -F(t), where (t) represents different times; The benefit evaluation value E(t) at each time point is calculated using E(t) = ΔF(t) × C(t), and the arithmetic mean E of the benefit evaluation values ​​at all times within the time interval Tzr where the periodic power needs to be supplemented is determined. avg ; The arithmetic mean E avg Compared with the preset benefit discrimination threshold E th Comparison; If E avg ≥E th The time interval Tzr for the periodic power to be supplemented is marked as the time interval for the optimal benefit to be supplemented, and then it is assigned to the set Tg for the optimal benefit to be supplemented in chronological order.

7. The system according to claim 6, characterized in that, In the preferred benefit range, if the arithmetic mean E of the periodic power to be compensated time interval Tzr is... avg <E th The time interval Tzr for the periodic power to be supplemented is marked as the time interval for the non-optimal benefit to be supplemented, and is then assigned to the set Tf of the non-optimal benefit to be supplemented time intervals in chronological order.

8. The system according to claim 7, characterized in that, The specific method for performing differentiated prior power regulation in the adaptive control terminal is as follows: Get the current time t in real time now Determine the current time t now The time interval type to which it belongs, if t now If ∈Tg, then obtain the current time t. now The power grid load F(t) now ), calculate the current power deficit ΔF(t) now )=max(F base -F(t now ),0); Get the current time t now Photovoltaic power generation P(t) now ) and energy storage state of charge (SOC(t) now ); Based on the rated capacity (SOC) of the energy storage device tot Preset minimum allowable state of charge (SOC) for energy storage min Given the control period Δt, calculate the maximum power P that the energy storage device can currently release. avi =min(P bm SOC(t) now )-SOC min )×SOC tot / Δt), where P bm This represents the maximum discharge power of the energy storage device. If P avi ≥ΔF(t now The power compensation method is determined to be energy storage-only compensation, and the power compensation amount is Q=ΔF(t). now It also sends a discharge power command Q to the energy storage converter. If P avi <ΔF(t) now The power compensation method is determined to be energy storage priority with photovoltaic auxiliary compensation, and the energy storage discharge power is P. avi The compensation power required by photovoltaics is ΔF(t) now )-P avi ; If the current photovoltaic power generation P(t) now )≥ΔF(t now )-P avi If the photovoltaic power supply is sufficient, the surplus will be provided; otherwise, the shortfall will be absorbed by the grid, and the power compensation will still be Q=ΔF(t).

9. The system according to claim 8, characterized in that, In the adaptive control terminal, if t now If ∈Tf, then the following differential prior power regulation is performed, specifically including: Determine the current power deficit ΔF(t) now ) and photovoltaic power generation P(t now ) and energy storage state of charge (SOC(t) now ); If P(t) now )≥ΔF(t now The power compensation method is determined to be photovoltaic separate compensation, and the power compensation amount is Q=ΔF(t). now ); If P(t) now )<ΔF(t now The photovoltaic power is entirely used to compensate the power grid, with the remaining deficit ΔF(t) now )-P(t now (Provided by energy storage devices) Extract the maximum power P that the energy storage device can currently release. avi ; If P avi ≥ΔF(t now )-P(t now The compensation method is determined to be joint compensation of photovoltaic energy storage, and the energy storage discharge power is ΔF(t). now )-P(t now The power compensation amount Q = ΔF(t) now ); If P avi <ΔF(t) now )-P(t now When the energy storage device discharges at full power and the remaining shortfall is absorbed by the grid, the power compensation amount remains Q=ΔF(t). now ).

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