Cooperative control method for load priority and demand control of photovoltaic energy storage system

Abstract

The invention discloses a cooperative control method for load priority and demand control of a photovoltaic energy storage system, relates to the technical field of new energy, and aims to solve the technical problem of low energy utilization efficiency. Calculating the target power of the energy storage system based on the photovoltaic power generation power and the load target power; and judging whether the photovoltaic power generation power is greater than the load target power. According to the cooperative control method for load priority and demand control of the photovoltaic energy storage system provided by the embodiment of the invention, efficient coordination among photovoltaic power generation, the energy storage system and the power grid load can be realized through organic combination of a load priority strategy and demand control; according to the method, the system can dynamically adjust the working state of each part according to the actual power demand, the utilization efficiency of energy is optimized, and meanwhile, the method can meet the load demand of a user to the maximum extent on the premise of demand control, so that the economic benefit is improved.

Description

Technical Field

[0001] The present invention relates to the field of new energy technology, and in particular to a collaborative control method for a photovoltaic energy storage system based on the load priority principle and demand control. Through an intelligent control strategy, efficient coordination between photovoltaic power generation, energy storage devices and power grid loads is achieved, thereby improving the energy utilization efficiency and economic benefits of the system. Background Art

[0002] In today's society, energy shortages and environmental pollution are becoming increasingly serious, prompting the development and utilization of renewable energy to become the focus of global attention. Photovoltaic power generation, as a clean and renewable energy form, has been widely used. However, due to the intermittent and random nature of photovoltaic power generation, its power generation is affected by factors such as climate conditions and light intensity, and it is impossible to achieve stable power output, which poses a challenge to the stability of the power system.

[0003] In order to cope with the volatility of photovoltaic power generation, energy storage systems have gradually become an important part of photovoltaic power generation systems. Through energy storage devices, the excess power of photovoltaic power generation systems can be stored when the light is strong and released when the light is insufficient, thereby ensuring the continuity and stability of power supply. However, in practical applications, the coordinated control between photovoltaic power generation systems and energy storage systems is often relatively simple, lacking the ability to dynamically respond to load demand, resulting in low energy utilization and poor economic benefits.

[0004] At present, there are two main control strategies for photovoltaic energy storage systems on the market: one is a strategy that prioritizes photovoltaic power generation, that is, photovoltaic power generation prioritizes load demand, and the remaining power is stored in the energy storage device; the other is a strategy that prioritizes energy storage, that is, the energy storage system is used to smooth the fluctuations of photovoltaic power generation and ensure stable power supply to the load. These two strategies can work in some scenarios, but in the case of large fluctuations in load demand, a single control strategy may lead to insufficient photovoltaic power generation or low utilization of the energy storage system, thereby affecting the performance of the overall system.

[0005] In addition, demand control, as an important means of optimizing the power system, aims to reduce the load pressure of the power grid during peak hours by controlling user loads, thereby reducing the high fees that power companies need to pay. However, in traditional photovoltaic energy storage systems, demand control is usually carried out independently from photovoltaic power generation and energy storage control, and an effective synergy mechanism has not been formed, resulting in the failure to fully realize the potential of demand control.

[0006] Based on the above background, the present invention proposes a coordinated control method of load priority and demand control of a photovoltaic energy storage system. Summary of the invention

[0007] The embodiment of the present invention provides a coordinated control method of load priority and demand control of a photovoltaic energy storage system, so as to at least solve the technical problem that a dynamic balance between load demand and photovoltaic power generation cannot be achieved and energy utilization efficiency is low;

[0008] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0009] A coordinated control method for load priority and demand control of a photovoltaic energy storage system comprises the following steps:

[0010] S1. Obtaining the parameters of the photovoltaic energy storage system, including photovoltaic power generation, load target power and capacity boundary of the energy storage system;

[0011] S2, calculating the target power of the energy storage system based on the photovoltaic power generation power and the load target power;

[0012] S3, judging whether the photovoltaic power generation power is greater than the load target power;

[0013] S4. If the photovoltaic power generation power is greater than the load target power, monitor whether the energy storage system is full. When the energy storage system is not full, control the energy storage system to charge. When the energy storage system is full, control the energy storage system to standby, and use zero power as the target power of the energy storage system.

[0014] S5. If the photovoltaic power generation power is less than the load target power, the energy storage system is controlled to discharge to supplement the difference between the load target power and the photovoltaic power generation power, and the difference is used as the target power of the energy storage system.

[0015] The collaborative control method of load priority and demand control of a photovoltaic energy storage system provided in an embodiment of the present invention can achieve efficient coordination between photovoltaic power generation, energy storage system and grid load through the organic combination of load priority strategy and demand control, so that the system can dynamically adjust the working state of each part according to actual power demand and optimize energy utilization efficiency. At the same time, the method can also maximize the satisfaction of user load demand under the premise of demand control, thereby improving economic benefits.

[0016] Furthermore, when the photovoltaic power generation is equal to the load target power, the energy storage system is controlled to standby, and zero power is used as the target power of the energy storage system. In this case, photovoltaic power generation just meets the load demand, and there is no need for the energy storage system to intervene, and the system operates in the optimal state.

[0017] Furthermore, when the energy storage system is in an undercharged state, when the energy storage system is controlled to charge, the charging power is equal to the difference between the photovoltaic power generation power and the load target power.

[0018] Furthermore, when the photovoltaic power generation is greater than the load target power and the energy storage system is not fully charged, the energy storage system is controlled to charge and the photovoltaic surplus power is stored in the energy storage system for future use. In this case, the charging of the energy storage system is prioritized to cope with the possible shortage of photovoltaic power generation in the future.

[0019] Furthermore, when the photovoltaic power generation power is greater than the load target power and the energy storage system is fully charged, the energy storage system is controlled to standby, with zero power as the target power of the energy storage system, and the photovoltaic system is controlled to reduce the power generation power, with the load target power as the photovoltaic power generation target power. This avoids energy waste and equipment overload. This method can not only prevent the energy storage system from overcharging, but also effectively protect photovoltaic power generation equipment.

[0020] Furthermore, if the photovoltaic power generation power is less than the load target power, monitor whether the energy storage system is discharged. When the energy storage system is not discharged, control the energy storage system to discharge. When the energy storage system is discharged, control the energy storage system to continue discharging.

[0021] Furthermore, when the photovoltaic power generation is less than the load target power and the energy storage system has power, the energy storage system is controlled to discharge and the energy storage system is used to supplement the insufficient photovoltaic power generation to ensure stable power supply to the load. At this time, the energy storage system plays its role in balancing power supply and demand and ensuring the normal operation of the user's load.

[0022] Furthermore, when the photovoltaic power generation is less than the load target power and the energy storage system is emptied, the energy storage system is controlled to continue discharging to maximize the part of the load power that is insufficient for photovoltaic power generation. Although the power is almost exhausted, the strategy of trying to supplement the part of the load power that is insufficient for photovoltaic power can still maximize the use of the remaining power of the energy storage system when power is scarce, ensuring the power supply of critical loads.

[0023] The specific beneficial effects are as follows:

[0024] 1. Improve energy utilization efficiency: Through the load priority strategy, the system can give priority to the use of photovoltaic power generation to meet load demand, store excess photovoltaic power in the energy storage system, reduce dependence on the power grid, and maximize energy utilization.

[0025] 2. Reduce grid demand: By collaboratively controlling demand and load, the system can effectively reduce grid load during peak power periods, reducing the power company's cost expenditure during peak periods.

[0026] 3. Enhance the economic benefits of the system: While ensuring the power supply to the load, the dynamic balance of photovoltaic power generation, energy storage and load is achieved through optimizing the control strategy, thereby improving the economic benefits of the photovoltaic power generation system and reducing the user's electricity expenditure.

[0027] 4. Improve the reliability and stability of the system: Through real-time monitoring and dynamic adjustment, ensure that the system can operate stably under various working conditions, especially when the photovoltaic power generation is insufficient or the energy storage system is low on power, it can still effectively guarantee the power supply to critical loads.

[0028] 5. Adaptability to a variety of application scenarios: The control method of the present invention is applicable to a variety of scenarios, such as household photovoltaic energy storage systems, industrial park power systems, distributed energy systems, etc., and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a flowchart of a method for coordinated control of load priority and demand control of a photovoltaic energy storage system. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0031] The embodiment of the present invention provides a coordinated control method for load priority and demand control of a photovoltaic energy storage system, see Figure 1 , including the following steps:

[0032] S1. Obtain the parameters of the photovoltaic energy storage system, including photovoltaic power generation, load target power and the capacity boundary of the energy storage system; the above parameters are the basis for the execution of the control strategy and can reflect the real-time operating status of the system. It should be noted that the capacity boundary of the energy storage system can be the current power and charging and discharging capacity of the battery.

[0033] S2. Calculate the target power of the energy storage system based on the photovoltaic power generation power and the load target power; by reasonably allocating the power of the energy storage system, it can ensure that the load is fully powered and improve the utilization efficiency of photovoltaic power.

[0034] S3, judging whether the photovoltaic power generation power is greater than the load target power;

[0035] S4. If the photovoltaic power generation power is greater than the load target power, monitor whether the energy storage system is full. When the energy storage system is not full, control the energy storage system to charge. The charging power is equal to the difference between the photovoltaic power generation power and the load target power. Store the photovoltaic surplus power in the energy storage system for future use. In this case, priority is given to ensuring the charging of the energy storage system to cope with the possible shortage of photovoltaic power generation in the future. When the energy storage system is full, control the energy storage system to standby, and use zero power as the target power of the energy storage system; at the same time, control the photovoltaic system to reduce the power generation, and use the load target power as the photovoltaic power generation target power to avoid energy waste and equipment overload. This method can not only prevent the energy storage system from overcharging, but also effectively protect photovoltaic power generation equipment.

[0036] S5. If the photovoltaic power generation power is less than the load target power, the energy storage system is controlled to discharge to supplement the difference between the load target power and the photovoltaic power generation power, and the difference is used as the target power of the energy storage system.

[0037] Specifically, if the photovoltaic power generation power is less than the load target power, monitor whether the energy storage system is discharged. When the energy storage system is not discharged, control the energy storage system to discharge. When the energy storage system is discharged, control the energy storage system to continue discharging.

[0038] When the photovoltaic power generation is less than the load target power and the energy storage system has power, the energy storage system is controlled to discharge and the energy storage system is used to supplement the load power that is insufficient for photovoltaic power generation to ensure stable power supply to the load. At this time, the energy storage system plays its role in balancing power supply and demand and ensuring the normal operation of the user's load.

[0039] When the photovoltaic power generation is less than the load target power and the energy storage system is emptied, the energy storage system is controlled to continue discharging to maximize the part of the load power that is insufficient for photovoltaic power generation. Although the power is almost exhausted, the strategy of trying to supplement the part of the load power that is insufficient for photovoltaic power can still maximize the use of the remaining power of the energy storage system when power is scarce, ensuring the power supply of critical loads.

[0040] S6: When the photovoltaic power generation is equal to the load target power, the energy storage system is controlled to standby, and zero power is used as the target power of the energy storage system. In this case, photovoltaic power generation just meets the load demand, and there is no need for the energy storage system to intervene, and the system operates in the optimal state.

[0041] The collaborative control method of load priority and demand control of a photovoltaic energy storage system provided in an embodiment of the present invention can achieve efficient coordination between photovoltaic power generation, energy storage system and grid load through the organic combination of load priority strategy and demand control, so that the system can dynamically adjust the working state of each part according to actual power demand and optimize energy utilization efficiency. At the same time, the method can also maximize the satisfaction of user load demand under the premise of demand control, thereby improving economic benefits.

[0042] The system collects power data in real time through sensors installed on the photovoltaic power generation unit, energy storage system and load side. These data are transmitted to the central control system through the wireless communication network for processing and analysis. Through real-time monitoring, the system can respond quickly to changes in power demand and ensure the stable operation of the entire system.

[0043] In order to improve the forward-looking control capability of the system, the present invention introduces a power demand forecasting model and a photovoltaic power generation forecasting model. Through the study and analysis of historical data, these models can accurately predict future power demand and photovoltaic power generation, providing a reliable basis for the scheduling of the energy storage system.

[0044] In power management, the present invention adopts an intelligent scheduling strategy. By introducing artificial intelligence technology, the system can adaptively adjust the power distribution of photovoltaic power generation, energy storage and load. For example, during periods of high grid electricity prices, the system can reduce the power consumption of the grid through optimization algorithms, giving priority to the use of energy storage systems and photovoltaic power generation.

[0045] The control method of the present invention is highly flexible and adaptable, and can be adjusted according to different application scenarios and requirements. For example, in home applications, the system pays more attention to the stability and economy of home loads; in industrial park applications, the system pays more attention to demand control and energy efficiency management; in distributed energy systems, the system emphasizes the coordination and integration of multiple energy sources.

[0046] The following are specific examples of three application scenarios:

[0047] Embodiment 1: In an embodiment based on the basic scheme of the collaborative control method of the photovoltaic energy storage system load priority and demand control: This embodiment takes the control method of the household photovoltaic energy storage system as an example. The photovoltaic power generation system is usually installed on the roof and connected to the household power system. The energy storage system usually uses a battery pack to store excess power generated by photovoltaic power generation. In this case, the control method of the present invention can be implemented by the following steps:

[0048] Step 1: Obtain energy storage system parameters: When the system starts, the controller first obtains the real-time power generation of the photovoltaic power generation system, the current power and charging and discharging capacity of the energy storage system, and the real-time demand of household electricity load.

[0049] Step 2: Calculate the target power of the energy storage system: Based on the real-time demand of photovoltaic power generation and household power load, the system calculates the target power of the energy storage system. The specific calculation steps are as follows:

[0050] Calculate the load gap: If the current photovoltaic power generation power is less than the household electricity load, the load gap is calculated, that is, the electricity demand that cannot be met by photovoltaic power generation, and this gap will be supplemented by the energy storage system.

[0051] Working mode of energy storage system:

[0052] Charging mode: When the photovoltaic power generation power is greater than the load demand and the energy storage system is not fully charged, the energy storage system enters the charging mode, absorbing the excess photovoltaic power and storing it in the battery.

[0053] Standby mode: When the photovoltaic power generation is equal to the load demand, or the photovoltaic power generation is greater than the load demand but the energy storage system is fully charged, the energy storage system enters standby mode and does not charge or discharge.

[0054] Discharge mode: When the photovoltaic power generation power is less than the load demand and the energy storage system has power, the energy storage system enters the discharge mode and releases the stored electric energy to supplement the shortfall of photovoltaic power generation.

[0055] Optimize power distribution: The system uses an optimization algorithm to balance the photovoltaic power generation, the available power of the energy storage system, and the real-time demand of the load, ensuring that energy utilization is maximized while meeting the load demand. When the photovoltaic power generation is greater than the load demand and the energy storage system is full, the system reduces the photovoltaic power generation to avoid energy waste, while ensuring the safety and stability of equipment operation.

[0056] In household applications, the control method of the present invention can increase the proportion of self-use of photovoltaic power generation, reduce household electricity expenses, and provide stable power supply support during power outages or peak electricity prices.

[0057] Embodiment 2: In another embodiment based on the basic scheme of the coordinated control method of the photovoltaic energy storage system load priority and demand control: This embodiment takes the control method of the photovoltaic energy storage system in the industrial park as an example; in the industrial park, due to the large load and strong volatility, the coordinated control of photovoltaic power generation and energy storage system becomes more complicated. The method of the present invention can be applied in the industrial park through the following steps:

[0058] The first step is to obtain the parameters of the energy storage system: the system obtains the photovoltaic power generation power of the industrial park, the power demand of each load area, the status of the energy storage system in real time. The status of the energy storage system includes battery power, charging and discharging capacity, and demand control target power.

[0059] The second step is to calculate the demand of the load area: statistics and analysis are conducted on the electricity demand of each load area in the industrial park. Combined with the photovoltaic power generation power, the power gap of each area is calculated, and the power output of the energy storage system is allocated according to priority.

[0060] The third step is to coordinate the control of photovoltaic power generation and energy storage systems: the system dynamically adjusts the charging and discharging status of the energy storage system according to the needs of each load area and the real-time situation of photovoltaic power generation. When photovoltaic power generation is sufficient, it gives priority to meeting the needs of high-priority loads and storing the remaining power. When photovoltaic power generation is insufficient, it gives priority to discharging to ensure the power supply of critical loads.

[0061] Step 4: Demand control: During peak hours of the power grid, by controlling the power consumption of non-critical loads in the industrial park, the peak demand can be reduced, reducing the fines or surcharges of the power company. At this time, the energy storage system can give priority to providing power support to the demand control load area when photovoltaic power generation is insufficient, so as to achieve the purpose of reducing the power grid demand.

[0062] Step 5. Multi-system linkage: To improve energy utilization efficiency, the system can also be linked with external power grids or other distributed energy systems. Through real-time monitoring and intelligent control, the system can reasonably dispatch photovoltaic power generation and energy storage resources while ensuring the electricity demand of the industrial park to achieve maximum economic benefits.

[0063] In industrial parks and commercial buildings, the demand control strategy of the present invention can significantly reduce demand electricity charges and achieve optimal management of electricity costs through intelligent scheduling of energy storage systems.

[0064] Embodiment 3: Another embodiment based on the basic scheme of the collaborative control method of photovoltaic energy storage system load priority and demand control: This embodiment takes the application in a distributed energy system as an example; a distributed energy system is usually composed of multiple photovoltaic power generation units, an energy storage system and a distributed load. Through the control method of the present invention, the intelligent management of the entire distributed energy system can be realized, and the overall efficiency of the system can be improved. The specific steps are as follows:

[0065] The first step is to obtain the parameters of the photovoltaic energy storage system: when the system starts, the real-time power of each photovoltaic power generation unit, the power of the energy storage system, and the power demand of each distributed load are obtained through the distributed energy management platform.

[0066] The second step is to predict future electricity demand and photovoltaic power generation based on data analysis and processing: The system processes data from each photovoltaic unit and load through big data analysis and prediction algorithms, predicts future electricity demand and photovoltaic power generation, and provides a basis for the scheduling of the energy storage system.

[0067] Step 3: Optimize control strategy: The system dynamically adjusts the working mode of photovoltaic power generation and energy storage system according to the prediction results and real-time data. For example, during the low load demand period, the system can increase the energy storage ratio of photovoltaic power generation; during peak periods, the discharge of the energy storage system is intelligently scheduled to ensure the stability of load power supply.

[0068] Step 4: Linkage control and external resource scheduling: When the photovoltaic power generation and energy storage system in the distributed system cannot meet the needs of all loads, the system can be linked to the external power grid or other distributed energy resources to achieve seamless switching of loads and avoid system failures.

[0069] Step 5. Emergency response mechanism: To deal with emergencies, such as a sudden drop in photovoltaic power generation or a failure of the energy storage system, the system has designed an emergency response mechanism. When an abnormal situation is detected, the system will automatically switch to emergency power supply mode to ensure continuous power supply to critical loads.

[0070] For distributed energy systems, the present invention can achieve efficient coordination among multiple energy sources, improve the overall energy efficiency of the system, support the construction of microgrids or independent power grids, and promote the development and promotion of renewable energy.

[0071] Based on actual application tests in different scenarios, the control method of the present invention has shown significant effects and advantages, as follows:

[0072] First, improvement of energy utilization efficiency: Actual test results show that through the method of the present invention, the energy utilization efficiency of the system has been significantly improved, the utilization rate of photovoltaic power generation has been increased by about 20%, the charging and discharging efficiency of the energy storage system has been increased by 15%, and the energy efficiency ratio of the overall system has been improved by more than 10%.

[0073] Second, improved economic benefits: In terms of economic benefits, through the optimization of control strategies and demand control, the user's electricity costs have been significantly reduced, especially in industrial applications, the demand cost during peak hours has dropped by 30%, and the overall electricity expenditure has been reduced by about 25%.

[0074] Third, the system stability is enhanced: The control method of the present invention significantly improves the stability of the system through real-time monitoring and dynamic adjustment. In the case of large fluctuations in photovoltaic power generation, the system can quickly respond to changes in load demand to ensure the continuity and stability of power supply.

[0075] Fourth, the embodiment of environmental benefits: By improving the utilization rate of photovoltaic power generation and reducing dependence on the power grid, the present invention also has positive significance in reducing carbon emissions and promoting environmental protection. By reducing the use of fossil fuels, the system reduces carbon emissions by about 10% in one year.

[0076] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0077] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A coordinated control method for load priority and demand control of a photovoltaic energy storage system, characterized in that: The following steps are involved: Obtaining the parameters of the photovoltaic energy storage system, including photovoltaic power generation, load target power, and the capacity boundary of the energy storage system; Calculate the target power of the energy storage system based on the photovoltaic power generation and the load target power; Determine whether the photovoltaic power generation power is greater than the load target power; If the photovoltaic power generation power is greater than the load target power, monitor whether the energy storage system is full. When the energy storage system is not full, control the energy storage system to charge. When the energy storage system is full, control the energy storage system to standby, and use zero power as the target power of the energy storage system. If the photovoltaic power generation power is less than the load target power, the energy storage system is controlled to discharge to supplement the difference between the load target power and the photovoltaic power generation power, and the difference is used as the target power of the energy storage system.

2. The coordinated control method of load priority and demand control of a photovoltaic energy storage system according to claim 1, characterized in that: When the photovoltaic power generation power is equal to the load target power, the energy storage system is controlled to standby, and zero power is used as the target power of the energy storage system.

3. The coordinated control method of load priority and demand control of a photovoltaic energy storage system according to claim 1, characterized in that: When the energy storage system is not fully charged, when the energy storage system is controlled to charge, the charging power is equal to the difference between the photovoltaic power generation power and the load target power.

4. The coordinated control method of load priority and demand control of a photovoltaic energy storage system according to claim 1, characterized in that: When the photovoltaic power generation power is greater than the load target power and the energy storage system is not fully charged, the energy storage system is controlled to charge and the photovoltaic surplus power is stored in the energy storage system for future use.

5. The coordinated control method of load priority and demand control of a photovoltaic energy storage system according to claim 1, characterized in that: When the photovoltaic power generation power is greater than the load target power and the energy storage system is fully charged, the energy storage system is controlled to standby, with zero power as the target power of the energy storage system. At the same time, the photovoltaic system is controlled to reduce the power generation power, with the load target power as the photovoltaic power generation target power.

6. The coordinated control method of load priority and demand control of a photovoltaic energy storage system according to claim 1, characterized in that: If the photovoltaic power generation power is less than the load target power, monitor whether the energy storage system is discharged. When the energy storage system is not discharged, control the energy storage system to discharge. When the energy storage system is discharged, control the energy storage system to continue discharging.

7. The coordinated control method of load priority and demand control of a photovoltaic energy storage system according to claim 6, characterized in that: When the photovoltaic power generation power is less than the load target power and the energy storage system has power, the energy storage system is controlled to discharge and the energy storage system is used to supplement the part of the load power that is insufficient for photovoltaic power generation to ensure stable power supply to the load.

8. The coordinated control method of load priority and demand control of a photovoltaic energy storage system according to claim 6, characterized in that: When the photovoltaic power generation power is less than the load target power and the energy storage system is discharged, the energy storage system is controlled to discharge continuously to maximize the supplement of the load power that is insufficient for the photovoltaic power generation power.

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