Photovoltaic energy storage direct current coupling intelligent micro-grid control method

Abstract

The invention relates to the technical field of photovoltaic power generation and energy storage, in particular to a photovoltaic energy storage direct current coupling intelligent micro-grid control method. According to a power control strategy, a mode of gradually increasing dynamic tracking is adopted, the power control problem under the scenes of combining protection / power reduction, demand countercurrent prevention, power deviation of a charging end and a discharging end and the like is solved, reaction time can be provided for detection equipment and control equipment, and the control power cannot be greatly increased in a pulse mode.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic power generation and energy storage, and in particular to a photovoltaic energy storage DC-coupled intelligent microgrid control method. Background Art

[0002] Against the backdrop of intensifying global energy supply and demand imbalances and a growing awareness of ecological conservation, the development of a green energy system is becoming a core challenge in overcoming development challenges. As a key enabler of the energy revolution, the efficient utilization of renewable energy not only overcomes bottlenecks in traditional energy supply but also shoulders multiple missions, including optimizing the energy landscape, ensuring strategic energy security, and restoring ecological balance. This transformative force is reshaping the path of sustainable development for human society and providing critical support for establishing a low-carbon, circular economy.

[0003] Photovoltaic technology, as a core solution for solar energy conversion, essentially achieves efficient conversion of light energy into electrical energy through the photovoltaic effect of semiconductor materials. PV energy storage systems, on the other hand, are the intelligent regulatory hub of this energy conversion chain. By managing the charge and discharge of energy storage devices, they establish a dynamic balance between power generation and consumption. This technological combination breaks the inherent synchronization of power generation and consumption in traditional power systems and creates a new paradigm for energy transfer in time and space.

[0004] In smart grid architectures, photovoltaic energy storage systems offer multiple applications. Their most significant benefit lies in load regulation: by storing energy during off-peak hours and releasing it during peak hours, the system effectively mitigates grid fluctuations, reducing line losses by 30%-50% and extending the life of transmission and distribution equipment by over 20%. This "energy time-shifting" feature not only improves grid operation economics but also enhances the power system's resilience to sudden load fluctuations.

[0005] It's important to note that the operational efficiency of smart microgrids is constrained by multiple factors. Photovoltaic power generation fluctuates unstably with the weather, and due to weather constraints, rated power generation often fails to be achieved. PV energy storage systems must track the current PV power in real time to regulate energy storage and PV power, performing load tracking. The control of PV DC / DC modules and DC / AC modules is subject to control delays, and control commands require response time. Furthermore, PV energy storage systems must also consider fault protection, power reduction, demand flow, and reverse flow during regulation, which poses significant challenges for control strategies. Summary of the Invention

[0006] In order to solve the above technical problems, the present invention provides a photovoltaic energy storage DC coupled smart microgrid control method for solving the problems existing in the prior art.

[0007] The present invention provides a photovoltaic energy storage DC coupled smart microgrid management method, comprising: S1: Collect microgrid data to determine the maximum output power that can be executed under extreme conditions in the event of fault protection. , the maximum output power Send to power control module; S2: Determine the instantaneous maximum power consumption of the park based on the demand power and backflow prevention power, including the maximum charging power and the maximum discharging power; S3: Setting the target power of the DC-AC by the power control module; S4: Use step-by-step dynamic tracking method to control photovoltaic power generation; S5: Output photovoltaic control power ; S6: Output DC-AC control power .

[0008] Preferably, the microgrid data includes the voltage and power limits of the energy storage battery cells. , Single cell temperature power limit , Single SOC power limit , BMS charging and discharging restrictions , BMS detects its own fault and sets the upload, equipment fault status acquisition power limit , DC-AC rated power ,in, .

[0009] Preferably, after the equipment fault status is collected, according to the fault protection level, in case of serious fault, the equipment fault status collection power limit If it is 0, the micro-electric gateway will be turned off and the power control module will be prompted and the fault location will be displayed when a serious fault occurs. If it is a medium fault, the power limit of the equipment fault status will be collected. When the value is 0, a medium fault reminder and the fault location are displayed on the power control module; when a minor fault occurs, a minor fault reminder and the fault location are displayed only on the power control module.

[0010] Preferably, the formula for calculating the maximum power consumption according to the demand power calculation formula is: , The maximum DC-AC power value that can be set after calculating the demand is is the current operating power of DC-AC, To determine the maximum demand value according to the capacity configuration of the park transformer, The step length of the demand setting value is the total number of grid-connected cabinets*2+2. The demand differential value is the range in which the power remains stable. The current operating power of the gateway meter.

[0011] Preferably, the maximum power consumption according to the anti-backflow power calculation formula is: , To calculate the target DC-AC maximum power value that can be set after backflow prevention, is the current operating power of DC-AC, To put the reverse flow margin value, it is used to judge in advance that the reverse flow is triggered and then the power reduction action is executed. To prevent backflow, set the value step size, which is the total number of grid-connected cabinets * 2 + 2. To prevent reverse flow and return to the differential value, this value is the range in which the power remains stable.

[0012] Preferably, the S3 sets the target power of the DC-AC through the power control module, specifically: , is the DC-AC target power, To control the input power through the interface of the power control module.

[0013] Preferably, the step S4 adopts a step-by-step increase dynamic tracking method to control the photovoltaic power generation power; specifically: When photovoltaic power generation can be absorbed, the photovoltaic power increases in steps. When it cannot be absorbed, it operates at the allowed power generation power using the following control process; ,in , : Photovoltaic control power, : Current operating power of photovoltaic, : PV control step length, : Current operating power of DC-AC.

[0014] Preferably, the S5 outputs photovoltaic control power Specifically: In the discharge process, the target power is controlled based on the DC-AC operating power. , = , ; During the charging process, the target power is controlled based on the energy storage operating power. 、 = 、 .

[0015] Preferably, the S6 outputs DC-AC control power Specifically: In actual operation, there is a fluctuation error of 0.5kW between the DCAC control power and the control unit's expected power. However, at this time, the energy storage is in a fully charged state, and the photovoltaic power generation power is equal to the DC-AC discharge power. At this time, the DC-AC power fluctuates downward by 0.5kW, and the 0.5kW is absorbed by the energy storage charging. The energy storage cannot be charged again when it is fully charged, and similarly, it cannot be discharged when it is empty. In view of this, logical processing is required in this scenario. When the SOC is greater than 90%, the DCAC power is ensured to be slightly greater than the photovoltaic power by 1kW to ensure low-power discharge of the energy storage. When the SOC is less than 10%, the DCAC power is ensured to be slightly less than the photovoltaic power, so that the energy storage can absorb the photovoltaic charging at low power. At this time, .

[0016] The embodiments of the present invention have the following technical effects: The application scenario of photovoltaic mounting on the DC side of energy storage in the present invention solves the problem of perfect combination of modules such as protection / power reduction, demand backflow prevention, and power deviation at the end of charging and discharging, so as to maximize the photovoltaic benefits; the power control strategy adopts a gradually increasing dynamic tracking method, that is, the real-time photovoltaic power data is collected once a second, and a certain amount is added to the current running power each time for control and distribution, so as to achieve the effect of power increasing slowly in a step-by-step manner; through the step-by-step power control method, the detection equipment and the control equipment can be given reaction time, so that the control power will not have a pulse-type large increase. Delays in detection and collection will result in the target power being reached, but due to slow collection, the control unit will mistakenly believe that the target power has not been reached and continue to increase the power output, thereby exceeding the rated power and damaging the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 This is a flow chart of a photovoltaic energy storage DC coupled smart microgrid control method provided by the present invention. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are also within the scope of protection of the present invention.

[0020] Example 1, as attached Figure 1 As shown, the present invention provides a photovoltaic energy storage DC coupled smart microgrid management method, comprising: S1: Collect microgrid data to determine the maximum output power that can be executed under extreme conditions in the event of fault protection. , sending the power to the power control module; Among them, microgrid data includes energy storage battery single voltage power limit , Single cell temperature power limit And single SOC power limit , further, when the single cell voltage is greater than 3.6V and less than 2.7V 0. When the temperature of the single battery is between 40~55℃ and -25~-5℃ is 0.

[0021] Microgrid data also includes BMS charging and discharging restrictions , BMS detects its own fault and sets it to upload. Equipment fault status acquisition power limit , DC-AC rated power .

[0022] Furthermore, when the equipment fault status is collected, according to the fault protection level, serious fault If the limit is 0, the micro-electric gateway will be turned off and a serious fault reminder will be displayed on the control module, along with the fault location. The limit is 0, and a medium fault reminder is displayed on the control module and the fault location is shown; a minor fault is only displayed on the control module and the fault location is shown.

[0023] in, .

[0024] S2: Determine the instantaneous maximum power consumption of the park based on the demand power and the backflow prevention power; Among them, the formula for calculating the maximum power consumption according to the demand power calculation formula is: , The maximum DC-AC power value that can be set after calculating the demand is is the current operating power of DC-AC, To determine the maximum demand value according to the capacity configuration of the park transformer. The step length of the demand setting value is generally the total number of grid-connected cabinets*2+2. The demand differential value is the range in which the power remains stable. The current operating power of the gateway meter.

[0025] According to the anti-backflow power calculation formula, the formula for maximum power consumption is: , To calculate the target DCAC maximum power value that can actually be set after backflow prevention, is the current operating power of DC-AC, To put the reverse flow margin value, it is used to judge in advance that the reverse flow is triggered and then the power reduction action is executed. To prevent backflow, the value step is generally set to the total number of grid-connected cabinets * 2 + 2. To prevent reverse flow and return to the differential value, this value is the range in which the power remains stable.

[0026] S3: Set the target power of DC-AC through the power control module; , is the DC-AC target power, To control the input power through the interface of the power control module.

[0027] S4: Use step-by-step dynamic tracking method to control photovoltaic power generation; When photovoltaic power generation can be absorbed, the photovoltaic power increases in steps. When it cannot be absorbed, it operates at the allowed power generation power using the following control process.

[0028] ,in , : Photovoltaic control power, : Current operating power of photovoltaic, : PV control step length, : Current operating power of DCAC.

[0029] S5: Output photovoltaic control power ; When the target power is set to DCAC operating power, . = , ; When the target power is set to the energy storage operation power, 、 = 、 .

[0030] S6: Output DC-AC control power ; In actual operation, there is a fluctuation error of 0.5kW between the DCAC control power and the expected power of the control unit. However, at this time, the energy storage is in a full state, and the photovoltaic power generation power is equal to the DCAC discharge power. At this time, the DCAC power fluctuates downward by 0.5kW. The 0.5kW is absorbed by the energy storage charging (due to the DC coupling of photovoltaic and energy storage). The energy storage cannot be charged again when it is fully charged, and similarly, it cannot be discharged when it is empty. In view of this situation, logical processing is required in this scenario. When the SOC is greater than 90%, ensuring that the DCAC power is slightly greater than the photovoltaic power by 1kW can ensure low-power discharge of the energy storage, thereby avoiding overcharging. When the SOC is less than 10%, ensuring that the DCAC power is slightly less than the photovoltaic power allows the energy storage to absorb the photovoltaic charging at low power. At this time, .

[0031] It should be noted that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the scope of this application. As shown in the present specification, unless the context clearly indicates an exception, the words "one", "a", "a kind of" and / or "the" do not specifically refer to the singular and may also include the plural. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method or device comprising a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method or device. In the absence of further restrictions, the elements defined by the sentence "comprise a..." do not exclude the presence of other identical elements in the process, method or device comprising the elements.

[0032] It should also be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the internal parts of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A photovoltaic energy storage DC coupled smart microgrid control method, characterized in that: include: S1: Collect microgrid data to determine the maximum output power that can be executed under extreme conditions in the event of fault protection. , the maximum output power Send to power control module; S2: Determine the instantaneous maximum power consumption of the park based on the demand power and backflow prevention power, including the maximum charging power and the maximum discharging power; S3: Setting the target power of the DC-AC by the power control module; S4: Use step-by-step dynamic tracking method to control photovoltaic power generation; S5: Output photovoltaic control power ; S6: Output DC-AC control power .

2. The photovoltaic energy storage DC-coupled smart microgrid control method according to claim 1, characterized in that: The microgrid data includes the voltage and power limits of the energy storage battery cells , Single cell temperature power limit , Single SOC power limit , BMS charging and discharging restrictions , BMS detects its own fault and sets the upload, equipment fault status acquisition power limit , DC-AC rated power ,in, .

3. The photovoltaic energy storage DC-coupled smart microgrid control method according to claim 2, characterized in that: After the equipment fault status is collected, according to the fault protection level, in case of serious fault, the equipment fault status collection power limit If it is 0, the micro-electric gateway will be turned off and the power control module will be prompted and the fault location will be displayed when a serious fault occurs. If it is a medium fault, the power limit of the equipment fault status will be collected. When the value is 0, a medium fault reminder and the fault location are displayed on the power control module; when a minor fault occurs, a minor fault reminder and the fault location are displayed only on the power control module.

4. The photovoltaic energy storage DC-coupled smart microgrid control method according to claim 1, characterized in that: According to the demand power calculation formula, the formula for maximum power consumption is: , The maximum DC-AC power value that can be set after calculating the demand is is the current operating power of DC-AC, To determine the maximum demand value according to the capacity configuration of the park transformer, The step length of the demand setting value is the total number of grid-connected cabinets*2+2. The demand differential value is the range in which the power remains stable. The current operating power of the gateway meter.

5. The photovoltaic energy storage DC coupled smart microgrid control method according to claim 1, characterized in that: According to the anti-backflow power calculation formula, the formula for maximum power consumption is: , To calculate the target DC-AC maximum power value that can be set after backflow prevention, is the current operating power of DC-AC, To put the reverse flow margin value, it is used to judge in advance that the reverse flow is triggered and then the power reduction action is executed. To prevent backflow, set the value step size, which is the total number of grid-connected cabinets * 2 + 2. To prevent reverse flow and return to the differential value, this value is the range in which the power remains stable.

6. The photovoltaic energy storage DC coupled smart microgrid control method according to claim 1, characterized in that: S3 sets the target power of the DC-AC through the power control module, specifically: , is the DC-AC target power, To control the input power through the interface of the power control module.

7. The photovoltaic energy storage DC coupled smart microgrid control method according to claim 1, characterized in that: The S4 adopts a step-by-step dynamic tracking method to control the photovoltaic power generation power; specifically: When photovoltaic power generation can be absorbed, the photovoltaic power increases in steps. When it cannot be absorbed, it operates at the allowed power generation power using the following control process; ,in , : Photovoltaic control power, : Current operating power of photovoltaic, : PV control step length, : Current operating power of DC-AC.

8. The photovoltaic energy storage DC coupled smart microgrid control method according to claim 1, characterized in that: The S5 output photovoltaic control power Specifically: In the discharge process, the target power is controlled based on the DC-AC operating power. , = , ; During the charging process, the target power is controlled based on the energy storage operating power. 、 = 、 .

9. The photovoltaic energy storage DC coupled smart microgrid control method according to claim 1, characterized in that: The S6 outputs DC-AC control power Specifically: In actual operation, there is a fluctuation error of 0.5kW between the DCAC control power and the control unit's expected power. However, at this time, the energy storage is in a fully charged state, and the photovoltaic power generation power is equal to the DC-AC discharge power. At this time, the DC-AC power fluctuates downward by 0.5kW, and the 0.5kW is absorbed by the energy storage charging. The energy storage cannot be charged again when it is fully charged, and similarly, it cannot be discharged when it is empty. In view of this, logical processing is required in this scenario. When the SOC is greater than 90%, the DCAC power is ensured to be slightly greater than the photovoltaic power by 1kW to ensure low-power discharge of the energy storage. When the SOC is less than 10%, the DCAC power is ensured to be slightly less than the photovoltaic power, so that the energy storage can absorb the photovoltaic charging at low power. At this time, .

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