Control method and system of optical storage direct flexible system

Abstract

The invention relates to the technical field of building electrics, and particularly provides a control method and system of an optical storage direct flexible system. The control method comprises the following steps: acquiring power load data of a target building within a preset time; acquiring illumination meteorological data in the preset time; obtaining a power load prediction curve according to the illumination meteorological data and the power load data; based on the power load prediction curve, constructing a control relationship between the direct current bus voltage at the grid-connected part of the optical storage direct-flexible system and the total grid-connected power; and based on the control relationship, performing power regulation according to the voltage change condition of the direct current bus. According to the invention, when the real-time power deviates from the predicted optimal load value, such as the inflection point, the optical storage direct-current flexible system can automatically deploy the power of the energy equipment connected to the direct-current bus. And system power response is completed according to the flexible capacity potential of the equipment, so that the system operation state tends to be economically optimal.

Description

Technical Field

[0001] The present invention relates to the field of building electrical technology, and specifically provides a control method and system for a photovoltaic storage direct-flexible system. Background Art

[0002] The "PV-storage-direct-flexible" system is a hot topic in the current research field of new energy power generation. The so-called "PV-storage-direct-flexible" means that the DC distribution network including new energy photovoltaic power generation equipment, energy storage equipment, DC load and AC flexible load can be called a PV-storage-direct-flexible distribution system. At present, with the advancement of clean energy, a high proportion of renewable energy structures have been widely penetrated in various industries. The PV-storage-direct-flexible distribution system is connected to the backbone power grid through a power converter. For the power grid, the entire PV-storage-direct-flexible distribution system has changed the traditional power balance relationship between the power supply side and the load side. From the grid side, the PV-storage-direct-flexible system has become a flexible load of the power grid. Each electrical equipment in the system can be adjusted in time according to the load demand relationship of the power system. Compared with the existing rigid load, the PV-storage-direct-flexible system helps to balance the load of the power system on the grid. Therefore, the PV-storage-direct-flexible system has attracted more and more attention from technicians in the power field.

[0003] Considering the demand for light from new energy photovoltaic power generation equipment, the photovoltaic storage direct-flexible system is usually combined with high-rise buildings to achieve photovoltaic storage direct-flexible based on construction projects, which can not only improve the supply and demand balance inside the building, but also help to achieve the supply and demand balance between the overall load demand of the building and the supply of the regional power grid. For a long time, the design of the building's power distribution system has been based on the basic requirements of satisfying the user experience and ensuring the safety and reliability of electrical equipment, while being closely integrated with building energy conservation. The technical path for the photovoltaic storage direct-flexible system to transform the microgrid system inside the building includes promoting the integration of multiple types of technologies, redesigning the microgrid system topology and grid-connected transformation, which promotes the multi-faceted improvement of the building's power distribution system, improves the flexibility, stability and robustness of the power supply within the microgrid system, and helps to flexibly combine the trend of low-carbon clean electricity consumption with lower economic transformation costs to achieve a variety of power consumption and power supply balances. The building power distribution system based on the photovoltaic storage direct-flexible system is not just a traditional rigid power load, but has become a flexible power load. After multi-dimensional integration with the power grid in the target area, it can flexibly adjust the process balance between the regional power grid and the local microgrid, so that the stability of the power system in the target area can be improved. The popular trend of photovoltaic storage direct-flexible system will cooperate with today's new energy electric vehicles, new energy distributed power generation, etc., flexibly integrate multiple energy sources; and promote urban construction and new energy technology development.

[0004] In the existing technology, although the photovoltaic storage direct-flexible system is a hot topic in current research and development, the interaction between the photovoltaic storage direct-flexible DC microgrid and the regional power system (such as when connected to the grid) will cause a certain impact on the regional power system, affecting the safety and stability of the regional power grid. If a large-scale photovoltaic storage direct-flexible system is directly connected, directly connected to the grid, or disconnected from the grid, the large change in the load value of the grid will cause an imbalance in supply and demand, causing rapid changes in the bus voltage of the grid, which is not conducive to the stability of the power system. Therefore, there is a technical problem in the existing control technology of the photovoltaic storage direct-flexible system that the control means are not good, resulting in a large impact on the power system. Summary of the invention

[0005] The present invention provides a control method and system for a photovoltaic-storage-direct-flexible system, so that the operation state of the photovoltaic-storage-direct-flexible system tends to be economically optimal.

[0006] In a first aspect, the present invention provides a control method for a solar-storage direct-flexible system, comprising:

[0007] Obtain the power load data of the target building within a preset time;

[0008] Acquire the sunlight and meteorological data within the preset time;

[0009] Obtaining a power load prediction curve according to the light meteorological data and the power load data;

[0010] Based on the power load prediction curve, a control relationship between the DC bus voltage and the total grid-connected power of the photovoltaic storage direct-flexible system at the grid-connected location is established;

[0011] Based on the control relationship, power regulation is performed according to the change of the DC bus voltage.

[0012] Furthermore, the historical power load data includes the power load level P within a unit time T. T And the power load curve P in the past nT time nT .

[0013] Furthermore, the light meteorological data includes temperature data, light intensity data, photovoltaic power generation power fluctuation characteristics, historical load levels, historical energy storage capacity levels in target buildings, and historical electricity prices.

[0014] Furthermore, obtaining a power load forecast curve according to the light meteorological data and the power load data includes:

[0015] Based on the light meteorological data and the power load data, a power load forecast curve is obtained, and a preset feeder voltage stability threshold is used as an optimization reference to obtain a power load forecast curve;

[0016] Furthermore, based on the power load forecast curve, constructing the control relationship between the DC bus voltage and the total grid-connected power at the grid-connected location of the photovoltaic storage direct-flexible system includes:

[0017] Based on the power load forecast curve, the grid-connected total threshold droop control curve is constructed;

[0018] The control relationship between the DC bus voltage and the total grid-connected power of the DC-flexible system at the grid-connected location is stored according to the droop control curve.

[0019] Furthermore, the control relationship constructed includes:

[0020] V d =V0+ΔV(t)=V0+L(x)·(P0-P r );

[0021] Wherein, P0 is the system grid-connected power prediction reference value based on the power load prediction curve of the day, Pr is the grid-connected power actually fed into the DC bus by the city power, V0 is the rated value of the DC bus voltage, and L(x) is the droop coefficient of the droop control curve; V d is the current DC bus voltage, ΔV(t) is the difference between the real-time load and the predicted load within time t.

[0022] Further, in the control relationship, based on the inflection point voltage U0, according to the numerical range of the DC bus voltage, the value of L(x) is determined, wherein the inflection point voltage U0 includes:

[0023]

[0024] In the above formula, U1 is the upper limit of the voltage, U2 is the lower limit of the voltage, a is the inflection point voltage adjustment coefficient, U(t) refers to the voltage of the PV-storage-DC-flexible system when the DC system is connected to the grid at time t, I(t) refers to the current of the PV-storage-DC-flexible system when the DC system is connected to the grid at time t, I0 refers to the rated current of the PV-storage-DC-flexible system when the DC system is connected to the grid, P nT is the power load curve in the past nT time.

[0025] Furthermore, the method further comprises:

[0026] According to the dynamic power regulation capacity of the load devices in the PV-storage direct-flexible system, the preset online capacity of each load device is iteratively adjusted in real time.

[0027] In a second aspect, the present invention provides a control system for a solar-storage direct-flexible system, comprising:

[0028] A data acquisition module is used to obtain the power load data of the target building within a preset time and the light and meteorological data within the preset time;

[0029] A power load forecast curve generating module, used for obtaining a power load forecast curve according to the light meteorological data and the power load data;

[0030] A photovoltaic, storage, direct current and flexible grid-connected control module, which constructs a control relationship between the DC bus voltage and the total grid-connected power at the photovoltaic, storage, direct current and flexible grid-connected system based on the power load prediction curve;

[0031] The photovoltaic storage direct current flexible intranet equipment control module is used to adjust the power according to the change of the direct current bus voltage based on the control relationship.

[0032] Furthermore, the method further comprises:

[0033] The overall coordination module is used to iteratively adjust the preset online capacity of each load device in real time according to the dynamic power adjustment capacity of the load device in the solar-storage direct-flexible system.

[0034] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0035] The present invention obtains the power load data within the preset time, closely associates the light meteorological data with the DC bus voltage, and sets the dynamic inflection point voltage U0 so that the dynamic adjustment of the grid-connected voltage can correspond to the internal operating power of the photovoltaic storage direct-flexible system, and through the droop control relationship, when the real-time power deviates from the predicted optimal load value, such as the inflection point, the photovoltaic storage direct-flexible system can automatically allocate the power of the energy equipment connected to the DC bus. The system power response is completed according to the flexible capacity potential of the equipment, so that the system operation state tends to be economically optimal. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The disclosure of the present invention will become more easily understood with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In addition, similar numbers in the figures are used to represent similar components, among which:

[0037] Figure 1 This is a schematic flow chart of the main steps of a control method for a solar-storage direct-flexible system according to an embodiment of the present invention;

[0038] Figure 2 is a schematic diagram of a power load forecasting curve according to an embodiment of the present invention;

[0039] Figure 3 is a schematic flow chart of steps S1-S6 according to an embodiment of the present invention;

[0040] Figure 4 It is a schematic diagram of the main structural block diagram of a control system of a solar-storage direct-flexible system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] Some embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0042] In the description of the present invention, "module" and "processor" may include hardware, software or a combination of the two. A module may include hardware circuits, various suitable sensors, communication ports, and memories, and may also include software parts, such as program codes, or a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor, or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware, or a combination of the two. Non-temporary computer-readable storage media include any suitable medium that can store program codes, such as a magnetic disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, and the like. The term "A and / or B" means all possible combinations of A and B, such as only A, only B, or A and B. The term "at least one A or B" or "at least one of A and B" has a similar meaning to "A and / or B", and may include only A, only B, or A and B. The singular terms "one" and "the" may also include plural forms.

[0043] Reference Figure 1 The present invention provides a control method for a solar-storage direct-flexible system, comprising:

[0044] S1, obtaining the power load data of the target building within a preset time;

[0045] S2, obtaining the light and meteorological data within the preset time;

[0046] S3, obtaining a power load prediction curve according to the light meteorological data and the power load data;

[0047] S4, based on the power load prediction curve, constructing a control relationship between the DC bus voltage and the total grid-connected power at the grid-connected location of the PV-storage-DC-flexible system;

[0048] S5: Perform power regulation based on the control relationship and according to the change of the DC bus voltage.

[0049] Steps S1 and S2 are both data acquisition processes and can be performed simultaneously. The sequence number in the method of the present invention serves as an identifier and does not limit the order of precedence.

[0050] Each step is described in detail below.

[0051] In one embodiment, in step S1, the target building is a solar-storage-direct-flexible building. The power load data is past power load data, i.e., historical data.

[0052] The power load data covers data sources with multiple time spans. Specifically, these data can come from power load records of the past year to reflect the load change trend of the year. Such data is helpful for analyzing the annual load change pattern. Similarly, it can also be the preset time in the past, which can be set to several hours according to the actual data collection needs. This setting is suitable for real-time monitoring of power loads, so as to quickly respond to load changes and ensure the stable operation of the power system.

[0053] The preset time can also be set to several days. This setting is suitable for predicting the power load in the future and providing a reference for power system planning and management.

[0054] The power load forecast curve provided by the present invention can be considered as a short-term power load forecast curve, so as to facilitate the dispatch and optimization of the power system in the short term. This short-term forecast curve has high accuracy and real-time performance, which helps to improve the operating efficiency and safety of the power system.

[0055] In an application scenario, load data for the past several hours is obtained.

[0056] In one embodiment, for the past power load data, with T as the time unit, the power load level P of the target building in the unit time T in the past is obtained by clustering method. T , and the power load curve P in the past nT time nT ; The clustering method can be a hierarchical method (Hierarchical Methods), a partitioning method (Parti t ioning Methods), a mean clustering algorithm or a model-based method (Model-Based Methods).

[0057] In one application scenario, the clustering method includes a K-means method.

[0058] In one embodiment, in step S2, the target building's past power load level P is obtained. T and power load curve P nT The light weather data at that time, record the temperature data Temp, light intensity data S in the data within the historical period nT p , photovoltaic power generation power fluctuation characteristics f p , historical load level L p 、The historical energy storage capacity level in the target building C p 、Historical electricity price F p .

[0059] In an application scenario, taking a solar-storage direct-flexible building in Shandong as an example, the data in Table 1 was obtained through field collection.

[0060] Table 1 Light and meteorological data

[0061]

[0062] In one embodiment, in step S3, obtaining a power load prediction curve according to the light meteorological data and the power load data includes:

[0063] A power load forecast curve is obtained based on the solar meteorological data and the power load data, and a power load forecast curve is obtained by taking a preset feeder voltage stability threshold as an optimization benchmark.

[0064] The feeder voltage stability threshold is preset, and in order to optimize subsequent steps, the optimization refers to taking the threshold as the starting point of the optimization.

[0065] In an application scenario, according to the parameters in Table 1, Figure 2 Electricity load forecast curve (within 12 hours).

[0066] Through step S3 of the present invention, the feeder voltage stability threshold is used as the optimization benchmark to obtain a short-term (such as future unit time t) power load forecast curve. The purpose of using the feeder voltage stability threshold as the optimization benchmark is:

[0067] 1. Ensure that when the target building is connected to the target area power grid, there will be no significant impact on the regional power grid due to voltage fluctuations. This helps reduce the risk of power system operation and improve the stability of the power grid;

[0068] 2. By optimizing the power load forecast curve, the operation strategy of the power system can be adjusted in real time to ensure that the voltage fluctuates within a reasonable range, avoid damage to power grid equipment caused by abnormal voltage, and contribute to the stability of regional voltage.

[0069] 3. Through accurate prediction and optimization of power load, the power grid loss can be reduced and the overall operating efficiency of the power system can be improved.

[0070] In one embodiment, in step S4, constructing the control relationship between the DC bus voltage and the total grid-connected power at the grid-connected location of the photovoltaic storage direct-flexible system based on the power load forecast curve includes:

[0071] S41, based on the power load forecast curve, construct the grid-connected total threshold droop control curve.

[0072] The present invention aims at the characteristics of the power load prediction curve and, based on this, constructs a voltage-power droop control curve of the rectifier between the AC power grid in the target area and the DC power grid of the photovoltaic storage flexible building.

[0073] The voltage-power droop control curve is composed of two droop control curves, and different droop control curves are connected by an inflection point. Then, the control relationship between the DC bus voltage and the total grid-connected power at the grid-connected DC system of the photovoltaic storage direct-flexible system is determined according to the voltage-power droop control curve.

[0074] Specifically, the voltage-power droop control curve is composed of two sections of droop control curves, which are connected by an inflection point. The voltage and power values ​​at the inflection point are key parameters, which determine the operating state of the rectifier under different load conditions.

[0075] There are two droop control curves, namely the first droop control curve and the second droop control curve. The slope of the first droop control curve is L1, and the corresponding DC bus voltage interval of the photovoltaic storage direct flexible power distribution system is (U0, U1], and the power interval is [P0, P1). Let the second droop control curve be L2, and the corresponding DC bus voltage interval is [U2, U0], and the power interval is (P1, P2], wherein L1>L2, U1 is the highest operating voltage allowed by the DC power grid, U2 is the lowest operating voltage allowed by the DC power grid, U0 is the inflection point voltage, P0 (0 is a number) is the power output of the rectifier when the operating voltage of the DC power grid is U2, P2 is the power output of the AC / DC converter when the operating voltage of the DC power grid is U1, P1 is the inflection point power, and the power transmitted by the rectifier to the DC power grid is recorded as the positive direction.

[0076] The invention dynamically adjusts the inflection point voltage U0 and the inflection point power P1, which are important parameters:

[0077]

[0078] In the above formula, U1 and U2 are the upper and lower limits of the voltage range of the direct-flexible distribution system, coefficient a is the inflection point voltage adjustment coefficient, and the value range is 0.85≤a≤0.95, while U(t) and I(t) refer to the voltage and current of the direct-flexible solar storage system at the time t when the direct-flexible solar storage system is connected to the grid, and current I0 refers to the rated current of the direct-flexible solar storage system at the grid. The purpose of the above formula is to calculate the power load level P of the target building based on the past power load level P of the target building within the unit time T. T The knee point voltage is dynamically adjusted based on the historical load level.

[0079] The above formula has significant advantages over the traditional voltage-power droop control curve calculation method. First of all, the above formula fully considers the historical load level of the photovoltaic storage direct-flexible system in the target building during the calculation process. This is because the output level of photovoltaic power generation is affected by meteorological conditions and fluctuates greatly. In the historical unit time T, the photovoltaic power generation system often deviates from the rated power supply during the power supply process. Specifically:

[0080] In the past unit time T, due to the instability of photovoltaic power generation levels, there may be a difference between the power supply of the photovoltaic storage direct-flexible system and the actual demand. This difference leads to fluctuations in the power load level.

[0081] In the past unit time T, the power at the point where the PV-storage direct-flexible system is connected to the AC grid in the target area will change due to changes in the photovoltaic power generation level. This change directly affects the power input from the AC grid in the target area to the target building.

[0082] Due to historical load fluctuations, the supplementary input power level of the AC grid in the target area to the target building will also change accordingly. This change is dynamic and needs to be adjusted according to actual conditions.

[0083] The formula of the present invention realizes dynamic adjustment of the inflection point voltage in the following manner:

[0084] In unit time T, the power load level P T is an important parameter in the knee voltage U0. Therefore, when P T When changes occur, the inflection point voltage U0 will also be adjusted accordingly.

[0085] By dynamically adjusting the inflection point voltage, the voltage-power droop control curve can be adjusted more accurately. This adjustment method takes into account factors such as historical load fluctuations, changes in grid-connected power, and supplementary input power levels, thereby improving the accuracy and adaptability of the voltage-power droop control curve.

[0086] In short, the DC system of the Zhongguang-storage direct-flexible system is connected to the AC grid in the target area within a unit time T, and the electric power input from the AC grid in the target area to the target building is dynamically adjusted based on the supplementary input power level of the AC grid in the target area to the target building. The supplementary input power level will affect the power load level P in the past unit time T. T , because P TIt is a parameter in the inflection point voltage, so it will affect the inflection point voltage U0. Therefore, the method of dynamically adjusting the inflection point voltage based on the above formula can make the voltage-power droop control curve based on the inflection point voltage more accurately adjusted. By dynamically adjusting the inflection point voltage, more accurate voltage-power droop control is achieved, providing more efficient and reliable support for the energy management of buildings.

[0087] At the same time, the calculation method for the inflection point power is as follows:

[0088] P1=U0×I0;

[0089] By adding an inflection point to the control voltage-power droop control curve of the grid-connected transformer, and setting the inflection point voltage to the DC limit voltage of the photovoltaic storage direct-flexible system, when the grid-connected transformer delivers power close to the rated power to the AC side, the absolute value of the slope of the droop control curve is very high, so that when the system operating voltage reaches the inflection point, the power space that the grid-connected transformer can adjust is low. At this time, the DC bus voltage will be much lower than the DC limit voltage allowed by the system. At this time, even if the voltage of the DC conversion device of the photovoltaic module in the photovoltaic storage direct-flexible system fluctuates, it is sufficient to change the maximum power tracking operation mode that is running before the operating voltage of the DC grid reaches the DC limit voltage to prevent the system from having an overvoltage. At the same time, the power space that the grid-connected transformer can adjust is low, so that the photovoltaic module operates at a higher power level. Therefore, through the coordinated control method of the present invention, if the grid-connected transformer fails, no additional power input is required, and the internal power self-sufficiency of the photovoltaic storage direct-flexible system can be met in a short time, so that both full utilization of photovoltaic resources and no overvoltage can be achieved.

[0090] According to the voltage-power droop control curve, the control relationship between the DC bus voltage and the total grid-connected power at the grid-connected location of the PV-storage DC-flexible system can be determined. By adjusting the output voltage of the rectifier, the DC bus voltage can be accurately controlled. According to the voltage-power droop control curve, the output power of the rectifier is adjusted in real time to adapt to the load changes of the power grid.

[0091] By constructing a voltage-power droop control curve, it helps to achieve stable operation of the power grid and efficient use of energy.

[0092] S42, storing the control relationship between the DC bus voltage and the total grid-connected power at the grid-connected location of the DC-flexible system according to the droop control curve determined in step S41.

[0093] By determining the control relationship between the DC bus voltage and power on the photovoltaic storage and direct-flexible system of the target building, the power can be flexibly adjusted according to the changes in the DC bus voltage.

[0094] In one embodiment, the control relationship constructed in step S42 includes:

[0095] V d =V0+ΔV(t)=V0+L(x)·(P e0 -P r );

[0096] Among them, P e0 is the system grid-connected power forecast benchmark value based on the daily power load forecast curve, P r is the grid-connected power actually fed into the DC bus by the mains, V0 is the rated value of the DC bus voltage, and L(x) is the droop coefficient of the droop control curve; V d is the current DC bus voltage, ΔV(t) is the difference between the real-time load and the predicted load within time t.

[0097] Whether L(x) takes the value of L1 or L2 depends on whether the DC bus voltage is in the interval (U0, U1] or in the range of [U2, U0), and then the corresponding voltage calculation is performed to achieve the control relationship. The specific judgment process of the value of L(x) is as follows.

[0098] In one embodiment, in the control relationship, based on the inflection point voltage U0, the value of L(x) is determined according to the numerical range of the DC bus voltage.

[0099] In an application scenario, U1, U2 and U0 are obtained according to S41, and the method for determining the value of L(x) based on this includes:

[0100] S421, determine whether the DC bus voltage Udc is greater than the voltage U2 and less than the voltage U0, that is, determine whether the DC bus voltage is in [U2, U0). If the DC bus voltage is in [U2, U0), execute step 422; otherwise, if the DC bus voltage is not in [U2, U0), execute step 423.

[0101] S422, execute the following control method: when the DC bus voltage is greater than voltage U2 and less than voltage U0, maintain the output power or power consumption of the grid-connected transformer, the energy storage module (such as supercapacitor group) in the photovoltaic storage direct and flexible system, the photovoltaic power generation components in the photovoltaic storage direct and flexible system, and various DC loads in the photovoltaic storage direct and flexible system at the current level.

[0102] S423, determine whether the DC bus voltage is less than voltage U2. If the DC bus voltage is less than voltage U2, it means that the current load is too heavy, jump to step 424, and perform corresponding operations; otherwise, it means that the current load needs to be adjusted, and if the DC bus voltage is not less than voltage threshold U2, execute step 425.

[0103] S424, according to the peak and valley state of the current grid load and supply, for example, when the bus voltage drops below the lower limit of the bus safety voltage due to excessive load or valley state, the power output of the energy storage module (such as supercapacitor group) in the photovoltaic storage direct and flexible system is determined; at the same time, the output power of the grid-connected transformer and the photovoltaic power generation components (such as photovoltaic arrays) in the photovoltaic storage direct and flexible system is increased; at the same time, the power consumption of various DC and AC loads in the photovoltaic storage direct and flexible system is reduced to increase the DC bus voltage. .

[0104] S425, determining whether the DC bus voltage is greater than a voltage threshold U0. If the DC bus voltage is greater than the voltage U0, executing step 426; otherwise, if the DC bus voltage is not greater than the voltage threshold U0, executing step 427.

[0105] S426, according to the current grid load and supply peak and trough conditions, determine the power output of the energy storage module (such as supercapacitor group) in the photovoltaic, storage, direct and flexible system; at the same time, reduce the output power of the grid-connected transformer and the photovoltaic power generation components (such as photovoltaic arrays) in the photovoltaic, storage, direct and flexible system; at the same time, increase the power consumption of the DC and AC load modules, but their maximum power consumption should be subject to the constraints of the whole network flow calculation of the target area and the maximum rated power, so as to prevent excessive consumption from affecting the overall voltage stability of the target area.

[0106] In some preferred embodiments, in step 426 , it is further determined whether the DC bus voltage is greater than the voltage U1 . If it is greater than the voltage U1 , the process jumps to step 427 .

[0107] S427, shut down the output power of some photovoltaic power generation components (such as photovoltaic arrays) in the photovoltaic storage direct and flexible system; at the same time, increase the power consumption of DC and AC load modules, and enable spare energy storage elements for energy storage, or notify the new energy electric vehicle group in the building where the photovoltaic storage direct and flexible system is located that the current charging price in the photovoltaic storage direct and flexible area will be reduced for a limited time to encourage more electric vehicles to connect to the photovoltaic storage direct and flexible system, which is conducive to smoothing the voltage of the DC bus of the photovoltaic storage direct and flexible system.

[0108] In one embodiment, referring to Figure 3 , the method further comprises:

[0109] S6, according to the dynamic power adjustment capacity of the load device in the solar-storage-direct-flexible system, the preset online capacity of each load device is adjusted in real time and iteratively.

[0110] In the current field of energy management, the optimization and control of the target building's photovoltaic, storage, direct and flexible system is particularly important. The present invention evaluates the dynamic power regulation capacity of the various load devices in the target building's photovoltaic, storage, direct and flexible system, and iterates and optimizes the preset on-grid capacity adjustment of each load device in real time to achieve coordinated control of the bus voltage in the photovoltaic, storage, direct and flexible system of the target building. It continuously adjusts the capacity regulation strategy of each load device to reduce energy consumption as much as possible while meeting actual needs.

[0111] Specifically, the present invention monitors the DC bus voltage Udc in real time to understand its fluctuations, provide a basis for subsequent control, and dynamically adjust the output power of the photovoltaic power generation components (such as photovoltaic arrays) in the photovoltaic storage direct-flexible system according to the fluctuations of the DC bus voltage Udc. Step S6 realizes the coordinated control of the bus voltage in the photovoltaic storage direct-flexible system of the target building.

[0112] In one embodiment, a method for controlling a photovoltaic power generation component in a photovoltaic storage direct-flexible system includes:

[0113] A power prediction model is constructed to predict the total power generated by photovoltaic modules. The constructed power prediction model is:

[0114] P = L × S × α × Q;

[0115] Among them, P is the total predicted power of photovoltaic power generation, L is the total solar radiation (MJ / ㎡); S is the sum of the areas of all components on the exterior wall of the building (㎡); α is the component conversion efficiency; Q is the energy consumption conversion coefficient in the power prediction model.

[0116] The photovoltaic crystalline silicon components on the exterior wall of the building are time-integrated and summed to obtain photovoltaic power generation power prediction data in the short term in the future.

[0117] The specific method for obtaining the parameters L and α in the power prediction model is described below.

[0118] (1) In the formula, the method for obtaining L is:

[0119] L = k(x·T h +y·T l +z·M+ΔL);

[0120] Among them, L is the total solar radiation (MJ / ㎡); ΔL is the change in total solar radiation; k is the daily solar radiation (MJ / ㎡ / day); T h is the daily maximum temperature (℃); T l is the daily minimum temperature (°C), M is the ultraviolet radiation intensity. x, y, z are weather coefficients in the power prediction model, which can be pre-set according to empirical values ​​or obtained by fitting historical data.

[0121] (2) In the formula, the method for obtaining α is:

[0122] The photovoltaic performance parameter data of the photovoltaic crystalline silicon components on the exterior wall of the building are extracted according to the photovoltaic storage direct flexible photovoltaic power generation components (such as photovoltaic arrays), and the energy conversion rate of the photovoltaic crystalline silicon components on the exterior wall of the building is calculated according to the photovoltaic performance parameter data of the photovoltaic crystalline silicon components on the exterior wall of the building:

[0123]

[0124] Where, α is the power conversion efficiency of the photovoltaic module; P o (subscript o is a letter) is the rated output power of the photovoltaic module, which is obtained through the photovoltaic performance parameter data of the photovoltaic crystalline silicon module on the exterior wall of the building; P i is the sunshine intensity received by the photovoltaic module, which is obtained through the module information and solar radiation. j(t) is the attenuation adjustment coefficient, which is the aging parameter curve determined in the aging experiment when the photovoltaic module leaves the factory.

[0125] Therefore, the power of the rooftop crystalline silicon modules is predicted according to the solar radiation and the conversion rate of the crystalline silicon modules on the building's exterior walls, and the total power generation power P of the photovoltaic modules is predicted according to the solar radiation and the conversion rate of the crystalline silicon modules on the building's exterior walls.

[0126] First, the present invention increases the correspondence between the building load prediction data and the rated bus, and closely associates this information with the DC bus voltage. The key information obtained includes but is not limited to the following: real-time monitoring and recording of the temperature changes of the day to predict its impact on the building load, analyzing and predicting the power fluctuations of the photovoltaic power generation system to accurately grasp its output characteristics, collecting and analyzing historical load data to predict future load change trends, real-time monitoring of the capacity status of energy storage equipment to provide a basis for subsequent power allocation, and adjusting the operation strategy of energy equipment according to changes in the time-of-use electricity price in the power market.

[0127] Then, the present invention sets a dynamic inflection point voltage U0 in the droop control curve, so that the dynamic adjustment of the grid-connected voltage can correspond to the internal operating power of the photovoltaic storage direct-flexible system (especially the power supply and demand balance within the system), and through the droop control relationship, when the real-time power deviates from the predicted optimal load value, the photovoltaic storage direct-flexible system can automatically allocate the power of the energy equipment connected to the DC bus, adjust the output power of the energy equipment according to the flexible capacity potential of the equipment, complete the rapid response of the system power, and make the system operation state tend to the economic optimum, thereby realizing the allocation and optimized operation of the photovoltaic storage direct-flexible system, and providing a more efficient and economical solution for building energy management.

[0128] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effects of the present invention, different steps do not have to be performed in such an order. They can be performed simultaneously (in parallel) or in other orders. These changes are within the scope of protection of the present invention.

[0129] The present invention also provides a coordinated control system for a photovoltaic storage direct-flexible system, referring to Figure 4 The system includes: a data acquisition module, a power load forecast curve generation module, a photovoltaic storage direct-flexible grid-connected control module, and a photovoltaic storage direct-flexible intranet equipment control module.

[0130] The data acquisition module is used to obtain the power load data of the target building within a preset time and the light and meteorological data within the preset time. Specifically, it is used to obtain the past power load data of the building power load, and through the big data clustering method, the clustering method can be a hierarchical method, a partitioning method, a mean clustering algorithm, or a model-based method, and the power load level P of the target building in the past within a unit time T is obtained through the clustering method. T , and the power load curve P in the past nT time nT And the data recorded within the historical period nT include the temperature data Temp, the light intensity data Sp, the photovoltaic power generation power fluctuation characteristics fp, the historical load level Lp, the historical energy storage capacity level Cp in the target building, and the historical electricity price Fp.

[0131] The power load forecast curve generation module is used to obtain the power load forecast curve according to the light meteorological data and the power load data. Specifically, the temperature data Temp, light intensity data Sp, photovoltaic power generation power fluctuation characteristics fp, historical load level Lp, historical energy storage capacity level Cp in the target building, and historical electricity price Fp in the recorded historical period nT are used to optimize the feeder voltage stability threshold.

[0132] The photovoltaic storage direct-flexible grid-connected control module constructs the control relationship between the DC bus voltage at the grid-connected location of the photovoltaic storage direct-flexible system and the total grid-connected power based on the power load forecast curve. Specifically, based on the power load forecast curve, a voltage-power droop control curve of the rectifier between the AC power grid in the target area and the DC power grid of the photovoltaic storage direct-flexible building is constructed. The voltage-power droop control curve is composed of two droop control curves, and different droop control curves are connected by an inflection point. Then, the control relationship between the DC bus voltage at the grid-connected location of the photovoltaic storage direct-flexible system and the total grid-connected power is determined based on the voltage-power droop control curve.

[0133] The control module of the photovoltaic, storage, direct and flexible intranet equipment, the control relationship performs power adjustment according to the change of the DC bus voltage. Specifically, the control relationship between the DC bus voltage at the grid-connected point of the photovoltaic, storage, direct and flexible DC system and the total grid-connected power is determined according to the voltage-power droop control curve, and the control relationship between the DC bus voltage and power on the photovoltaic, storage, direct and flexible system is set for the target building, so that power can be flexibly adjusted according to the change of the DC bus voltage.

[0134] In one embodiment, the system further includes an overall coordination module.

[0135] The overall coordination module is used to iteratively adjust the preset online capacity of each load device in real time according to the dynamic power regulation capacity of the load device in the PV-storage-direct-flexible system. Specifically, the dynamic power regulation capacity of the various load devices in the PV-storage-direct-flexible system of the target building is evaluated, and the preset online capacity regulation of each load device is optimized in real time through continuous calculation in each cycle, so as to realize the coordinated control of the bus voltage in the PV-storage-direct-flexible system of the target building.

[0136] It is understood by those skilled in the art that the main process (steps S3-S5 of the control method of the optical storage direct and flexible system) in the method of implementing the above embodiment of the present invention can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of each of the above method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electric carrier signal, telecommunication signal and software distribution medium that can carry the computer program code. It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electric carrier signals and telecommunication signals.

[0137] Furthermore, the present invention also provides a control device. In one embodiment of the control device according to the present invention, the control device includes a processor and a storage device. The storage device can be configured to store a program for executing the control method of the photovoltaic storage direct and flexible system of the above method embodiment, and the processor can be configured to execute the program in the storage device, which includes but is not limited to the program for executing steps S3-S5 of the control method of the photovoltaic storage direct and flexible system of the above method embodiment. For ease of explanation, only the parts related to the embodiment of the present invention are shown. For specific technical details not disclosed, please refer to the method part of the embodiment of the present invention. The control device can be a control device device formed by various electronic devices.

[0138] Furthermore, the present invention also provides a computer-readable storage medium. In a computer-readable storage medium embodiment according to the present invention, the computer-readable storage medium can be configured to store a program for executing the control method of the optical-storage direct-flexible system of the above-mentioned method embodiment, and the program can be loaded and run by the processor to implement steps S3-S5 of the control method of the optical-storage direct-flexible system. For ease of explanation, only the parts related to the embodiment of the present invention are shown. For specific technical details not disclosed, please refer to the method part of the embodiment of the present invention. The computer-readable storage medium can be a storage device formed by various electronic devices. Optionally, the computer-readable storage medium in the embodiment of the present invention is a non-temporary computer-readable storage medium.

[0139] It can be seen from the above embodiments that, compared with the prior art, the advantages of the present application are:

[0140] (A) The present invention closely associates key information such as the climate temperature change of the day, the fluctuation characteristics of photovoltaic power generation power the day before, the load operation of the day before, the state of energy storage capacity the day before, and the time-of-use electricity price information of the day with the DC bus voltage by increasing the correspondence between the building load forecast data and the rated bus. By setting the dynamic inflection point voltage U0, the dynamic regulation of the grid-connected voltage can correspond to the internal operating power of the photovoltaic storage direct-flexible system (especially the power balance of supply and demand within the system), and through the droop control relationship, when the real-time power deviates from the predicted optimal load value, such as the inflection point, the photovoltaic storage direct-flexible system can automatically allocate the power of the energy equipment connected to the DC bus. The simplest allocation is to fill the power gap and operate at the most economical power point value. The system power response is completed according to the flexible capacity potential of the equipment, so that the system operation state tends to be economically optimal.

[0141] (B) The present invention introduces a coordinated control method for a photovoltaic, storage, direct and flexible system for short-term prediction, which fully considers the total solar radiation, daily solar radiation, daily maximum temperature, daily minimum temperature, and ultraviolet radiation intensity, and sets them as weather coefficients in the power prediction model. The photovoltaic performance parameter data of the photovoltaic crystalline silicon modules on the exterior wall of the building are extracted based on the photovoltaic performance parameter data of the photovoltaic crystalline silicon modules on the exterior wall of the building, and the energy conversion rate of the photovoltaic crystalline silicon modules on the exterior wall of the building is calculated based on the photovoltaic performance parameter data of the photovoltaic crystalline silicon modules on the exterior wall of the building, thereby realizing accurate calculation of the output inside the photovoltaic, storage, direct and flexible system.

[0142] (C) The present invention increases the correspondence between the building load prediction data and the rated bus voltage, fully considers the key information such as daily climate temperature changes, photovoltaic power generation power fluctuation characteristics, load operation conditions, energy storage capacity status, daily time-of-use electricity price information and the DC bus voltage, so that the rated bus voltage condition can correspond to the optimal operating power, and through the droop control relationship, when the real-time power deviates from the predicted optimal load value, the photovoltaic storage direct-flexible system can automatically allocate the power of the energy equipment connected to the DC bus, and the amount connected is the power difference gap. Therefore, the system power response is completed according to the flexible capacity potential of the equipment, so that the system operation state tends to be economically optimal.

[0143] Further, it should be understood that since the setting of each module is only for illustrating the functional units of the device of the present invention, the physical devices corresponding to these modules may be the processor itself, or a part of the software in the processor, a part of the hardware, or a part of the combination of software and hardware. Therefore, the number of each module in the figure is only schematic.

[0144] Those skilled in the art will appreciate that the modules in the device can be adaptively split or merged. Such splitting or merging of specific modules will not cause the technical solution to deviate from the principle of the present invention, and therefore, the technical solutions after splitting or merging will fall within the protection scope of the present invention.

[0145] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A control method for a solar-storage direct-flexible system, characterized in that: include: Obtain the power load data of the target building within a preset time; Acquire the sunlight and meteorological data within the preset time; Obtaining a power load prediction curve according to the light meteorological data and the power load data; Based on the power load prediction curve, a control relationship between the DC bus voltage and the total grid-connected power of the photovoltaic storage direct-flexible system at the grid-connected location is established; Based on the control relationship, power regulation is performed according to the change of the DC bus voltage.

2. The method according to claim 1, characterized in that The historical power load data includes the power load level P within a unit time T. T And the power load curve P in the past nT time nT .

3. The method according to claim 1, characterized in that The light meteorological data includes temperature data, light intensity data, photovoltaic power generation power fluctuation characteristics, historical load levels, historical energy storage capacity levels in target buildings, and historical electricity prices.

4. The method according to claim 1, characterized in that: The obtaining of the power load forecast curve according to the light meteorological data and the power load data comprises: A power load forecast curve is obtained based on the solar meteorological data and the power load data, and a power load forecast curve is obtained by taking a preset feeder voltage stability threshold as an optimization benchmark.

5. The method according to claim 1, characterized in that The control relationship between the DC bus voltage and the total grid-connected power of the photovoltaic storage direct-flexible system at the grid-connected location based on the power load prediction curve includes: Based on the power load forecast curve, the grid-connected total threshold droop control curve is constructed; The control relationship between the DC bus voltage and the total grid-connected power of the DC-flexible system at the grid-connected location is stored according to the droop control curve.

6. The method according to claim 5, characterized in that The control relationship constructed includes: V d =V0+ΔV(t)=V0+L(x)·(P0-P r ); Wherein, P0 is the system grid-connected power prediction reference value based on the power load prediction curve of the day, Pr is the grid-connected power actually fed into the DC bus by the city power, V0 is the rated value of the DC bus voltage, and L(x) is the droop coefficient of the droop control curve; V d is the current DC bus voltage, ΔV(t) is the difference between the real-time load and the predicted load within time t.

7. The method according to claim 6, characterized in that In the control relationship, based on the inflection point voltage U0, according to the numerical range of the DC bus voltage, the value of L(x) is determined, wherein the inflection point voltage U0 includes: In the above formula, U1 is the upper limit of the voltage, U2 is the lower limit of the voltage, a is the inflection point voltage adjustment coefficient, U(t) refers to the voltage of the PV-storage-DC-flexible system when the DC system is connected to the grid at time t, I(t) refers to the current of the PV-storage-DC-flexible system when the DC system is connected to the grid at time t, I0 refers to the rated current of the PV-storage-DC-flexible system when the DC system is connected to the grid, P nT is the power load curve in the past nT time.

8. The method according to claim 1, characterized in that: The method further comprises: According to the dynamic power regulation capacity of the load devices in the PV-storage direct-flexible system, the preset online capacity of each load device is iteratively adjusted in real time.

9. A control system for a solar-storage direct-flexible system, characterized in that: include: A data acquisition module is used to obtain the power load data of the target building within a preset time and the light and meteorological data within the preset time; A power load forecast curve generating module, used for obtaining a power load forecast curve according to the light meteorological data and the power load data; A photovoltaic, storage, direct current and flexible grid-connected control module, which constructs a control relationship between the DC bus voltage and the total grid-connected power at the photovoltaic, storage, direct current and flexible grid-connected system based on the power load prediction curve; The photovoltaic storage direct current flexible intranet equipment control module is used to adjust the power according to the change of the direct current bus voltage based on the control relationship.

10. The system according to claim 9, characterized in that Also includes: The overall coordination module is used to iteratively adjust the preset online capacity of each load device in real time according to the dynamic power adjustment capacity of the load device in the solar-storage direct-flexible system.

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