Light-storage direct-flexible building system based on centralized energy storage

Abstract

The invention discloses an optical storage direct-flexible building system based on centralized energy storage, and relates to the technical field of energy and electric power systems, and the system is characterized in that a distributed household photovoltaic system carries out electric power mutual transmission with a village-level centralized energy storage station through a low-voltage direct-current power distribution network, and an electric energy router dynamically adjusts electric power flow according to real-time power generation and load conditions. The power demand of the direct-current load of the household is preferentially ensured, and when more power is generated, redundant power is supplied to the movable energy storage load through the low-voltage direct-current power distribution network or stored in the village-level centralized energy storage station; when power generation is insufficient, power is taken from the village-level centralized energy storage station through the low-voltage direct-current power distribution network; the village-level centralized energy storage station and the low-voltage direct-current power distribution network carry out electric power bidirectional exchange through the PCS, and when the electric power of the village-level centralized energy storage station is sufficient, excess electric power is returned to the low-voltage direct-current power distribution network through the PCS; when the electric power of the village-level centralized energy storage station is insufficient, the electric power is obtained from the low-voltage direct-current power distribution network, and continuous power supply of the household direct-current load is ensured through combination of centralized energy storage and movable energy storage.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy and power systems, and specifically relates to a photovoltaic storage direct-flexible building system based on centralized energy storage. Background Art

[0002] "PV-storage-direct-flexible" buildings refer to new building distribution systems that meet the needs of carbon neutrality goals through photovoltaic power generation, energy storage, DC power distribution and flexible energy use. Its ultimate goal is to achieve flexible energy use of the entire building, so that the building is transformed from a mere load in the traditional energy system to a complex with the "three-in-one" functions of renewable energy production, self-energy use, and energy regulation and storage in the entire energy system in the future, so as to realize the on-site consumption of renewable energy. The "PV-storage-direct-flexible" "PV" refers to distributed photovoltaic power generation; "storage" refers to energy storage technology, which is used to alleviate the time mismatch between photovoltaic power generation and power load; "direct" represents the DC distribution system, which can reduce transmission losses and improve the overall efficiency of power generation and power consumption by realizing the direct output and use of photovoltaic power generation, eliminating the "inverter access to the grid" and "rectifier power use" links; "flexible" includes two technologies: flexible regulation of electrical equipment itself and dynamic matching between photovoltaics, energy storage and load.

[0003] Research on rural photovoltaic resources shows that rural areas have vast rooftop resources and potential for photovoltaic installation. Therefore, rural buildings are expected to become important distributed photovoltaic resources. The promotion of the "solar storage direct and flexible" building system in rural areas can make full use of local rooftop resources and decentralized layout advantages to achieve energy self-sufficiency and improve the quality of life, and promote the sustainable development of rural economy and environment. This system can bring direct economic benefits to farmers and contribute to the construction of green and modern rural areas.

[0004] The existing technology proposes a rural "solar storage direct and flexible" building that adopts distributed photovoltaic and distributed energy storage solutions, that is, each household is equipped with a distributed photovoltaic and energy storage system. This has the following defects and challenges: (1) High cost. Installing an energy storage system for each household involves high initial investment and maintenance costs, and with the rapid development of technology, early equipment may face the risk of depreciation.

[0005] (2) Maintenance and management are complex. Regular inspection and real-time monitoring are required, which is particularly difficult for families with a lack of technical background.

[0006] (3) Safety risks. Lithium battery energy storage systems may cause fires when exposed to high temperatures or physical damage, and may also cause electrical failures when connected to a home power grid.

[0007] (4) Resource waste and efficiency issues. Due to the decentralized layout, energy utilization efficiency is low, which easily leads to resource waste and equipment redundancy.

[0008] (5) Grid management challenges. The access of a large number of household energy storage systems also poses a challenge to the stability of the grid. The lack of a unified coordination mechanism will cause voltage fluctuations or frequency instability. Summary of the invention

[0009] The purpose of the present invention is to address the above-mentioned problems and propose a photovoltaic storage direct-flexible building system based on centralized energy storage. It adopts the form of a centralized energy storage station, which can achieve the beneficial effects of reducing initial investment and maintenance costs, improving energy utilization efficiency, enhancing system safety, stabilizing grid operation and simplifying coordination between the grid and users.

[0010] The present invention provides a photovoltaic storage direct-current flexible building system based on centralized energy storage, including a distributed household photovoltaic system, a household DC load, an energy router, a low-voltage DC distribution network, a village-level centralized energy storage station, an active energy storage load, an energy storage converter, and city power. The distributed household photovoltaic system transmits electricity to and from the village-level centralized energy storage station through the low-voltage DC distribution network. The energy router dynamically adjusts the flow of electricity according to the real-time power generation and load conditions, giving priority to ensuring the power demand of the household DC load. When more power is generated, the excess power is transferred through the low-voltage DC distribution network. The DC distribution network is used to charge active energy storage loads or store them in village-level centralized energy storage stations. When power generation is insufficient, power is obtained from the village-level centralized energy storage station through the low-voltage DC distribution network. The village-level centralized energy storage station and the low-voltage DC distribution network exchange power in both directions through energy storage inverters. When the power of the village-level centralized energy storage station is sufficient, the excess power is fed back to the low-voltage DC distribution network through the energy storage inverter. When the power of the village-level centralized energy storage station is insufficient, power is obtained from the low-voltage DC distribution network. Through the combination of centralized energy storage and active energy storage, continuous power supply to household DC loads is ensured.

[0011] Preferably, the distributed household photovoltaic system power generation system is installed on the surface of an existing building, and the DC power generated by the system is used to provide power supply for the user's DC appliances.

[0012] Preferably, the household DC load is an electrical device directly connected to the distributed household photovoltaic system. By directly using the DC power generated by photovoltaic power generation, the household DC load reduces power conversion losses.

[0013] Preferably, the power router dynamically allocates power according to photovoltaic power generation and load demand.

[0014] As a priority, photovoltaic power generation will give priority to meeting the household DC load. When power generation is insufficient, electricity will be obtained from the low-voltage DC distribution network. When power generation is excessive, excess electricity will be sent to the low-voltage DC distribution network or the village-level centralized energy storage station.

[0015] Preferably, the low-voltage DC distribution network is used to distribute and transmit DC power, and by adopting DC transmission, it deeply matches the rural distributed energy scenario.

[0016] Preferably, the village-level centralized energy storage station is responsible for collecting, storing and managing excess electricity from distributed household photovoltaic systems. When photovoltaic power generation is insufficient, the energy storage station provides stable power for the load.

[0017] Preferably, the active energy storage load includes an energy storage device that is adjusted under specific needs, and the operating time is flexibly adjusted according to the state of power supply. Through flexible scheduling, the active energy storage load is charged during peak power generation period and excess electricity is stored.

[0018] Preferably, the energy storage converter is responsible for converting power between direct current and alternating current, and managing the flow of power between the energy storage system and the power grid.

[0019] Preferably, the combination of centralized energy storage and active energy storage is achieved through dynamic power dispatching and rational allocation of resources. The village-level centralized energy storage station serves as the energy storage unit of the photovoltaic direct-flexible building system, responsible for absorbing excess power from distributed household photovoltaic systems and providing power support when the distributed household photovoltaic systems generate insufficient power, thereby balancing supply and demand and stabilizing the overall power supply of the system.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention is designed based on the electricity consumption characteristics of the photovoltaic storage direct-flexible building system (rural buildings) with centralized energy storage. The design of the present invention profoundly reflects the significant differences in electricity consumption habits between rural power grids and urban power grids. The electricity consumption pattern in rural areas is usually characterized by less electricity demand during the day and a significant increase in electricity demand at night. The photovoltaic system generates electricity during the day but cannot provide electricity at night. Urban power grids tend to have a more uniform and stable load distribution. Therefore, the design of this system specifically considers the characteristics of rural electricity consumption, and achieves an effective balance between daytime and nighttime electricity consumption through the combination of centralized energy storage and mobile energy storage.

[0021] 2. The present invention avoids the high initial investment and complex maintenance requirements brought about by each household's independent installation of an energy storage system through the use of village-level centralized energy storage stations, thereby reducing the overall cost and technical management difficulty. Improved energy utilization efficiency. Village-level centralized energy storage stations can achieve optimal allocation of resources and efficient use of energy through unified power dispatching and management, reducing resource waste and equipment redundancy problems in decentralized energy storage systems. In addition, village-level centralized energy storage stations also enhance the overall safety of the system. Centrally managed energy storage systems can monitor and maintain equipment more effectively, reduce safety risks such as fires caused by energy storage systems, and reduce the difficulties of household users in management and operation.

[0022] 3. The present invention can better manage the balance between photovoltaic power generation and power load through the combination of centralized energy storage and mobile energy storage, maximize the use of excess power from photovoltaic power generation, avoid voltage fluctuations and frequency instability problems caused by decentralized energy storage systems, and thus improve the stability and reliability of the regional power grid.

[0023] 4. The village-level centralized energy storage station and low-voltage DC power distribution system of the present invention can make the electric energy flow internally first, and the insufficient or excess part can interact with the AC network through the centralized grid connection point, so as to always maximize the local utilization of new energy. It also reduces the interaction with the power grid, reduces the impact on the power grid, and simplifies the power coordination work between the power grid and users.

[0024] 5. The present invention adopts a working mode that combines centralized energy storage with mobile energy storage, which not only ensures the direct and efficient use of photovoltaic power generation, but also provides long-term, large-scale power regulation through centralized energy storage, while the mobile energy storage load realizes short-term, flexible load regulation, thereby achieving efficient operation of the system under different load demands and optimal energy configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation method described herein is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0027] Example 1: Please refer to the attached Figure 1This embodiment provides a photovoltaic storage and direct-flexible building system based on centralized energy storage, including a distributed household photovoltaic system, a household DC load, an energy router, a low-voltage DC distribution network, a village-level centralized energy storage station, an active energy storage load, an energy storage inverter, and city power. The specific working principle is as follows: the distributed household photovoltaic system transmits electricity to the village-level centralized energy storage station through the low-voltage DC distribution network. The energy router dynamically adjusts the power flow according to the real-time power generation and load conditions, giving priority to the power demand of the household DC load. When the power generation is high, the excess power is transferred to the local DC load. Active energy storage loads are charged or stored in village-level centralized energy storage stations through the low-voltage DC distribution network. When power generation is insufficient, electricity is obtained from the village-level centralized energy storage station through the low-voltage DC distribution network. The village-level centralized energy storage station and the low-voltage DC distribution network exchange electricity in both directions through the energy storage inverter. When the village-level centralized energy storage station has sufficient power, the excess power is fed back to the low-voltage DC distribution network through the energy storage inverter. When the village-level centralized energy storage station has insufficient power, power is obtained from the low-voltage DC distribution network. Through the combination of centralized energy storage and active energy storage, continuous power supply to household DC loads is ensured.

[0028] Among them, the distributed household photovoltaic system power generation system is installed on the surface of existing buildings (such as roofs and walls), and the DC power generated by it is used to provide power supply for users' DC appliances. Since the photovoltaic modules are installed on the surface of existing buildings, no additional land resources are required, thus reducing land leasing and related construction and maintenance costs.

[0029] Secondly, the output power of distributed household photovoltaic systems is relatively small, and the scale can be flexibly adjusted: the capacity of distributed photovoltaic power generation projects ranges from several kilowatts to several megawatts, and the output power is much smaller than that of large ground photovoltaic power stations. The scale can be adjusted through the modular design of photovoltaic power generation, and the capacity of the photovoltaic system can be adjusted according to factors such as roof area and construction conditions. The installation method is relatively flexible and suitable for decentralized construction in energy-intensive areas. Distributed photovoltaic power generation does not cause pollution and noise during the power generation process, and will not pollute the air and water, so it is suitable for development in rural areas.

[0030] Power generation and consumption coexist, and transmission line losses are low: Distributed photovoltaic power generation is connected to the distribution network, directly generated and used, and most of it can be consumed locally. Because it does not require long-distance transmission, there is no line loss, and it is directly consumed in the distribution network, and the utilization rate is generally high.

[0031] Close to the load center, little impact on the power grid: Distributed photovoltaics do not need long-distance transmission, saving grid costs. Rural areas are generally small in scale, and have limited impact on the frequency and voltage fluctuations of the power grid.

[0032] The design of this solution deeply reflects the significant differences in electricity consumption habits between rural power grids and urban power grids. The electricity consumption pattern in rural areas is usually characterized by less electricity demand during the day and a significant increase in electricity demand at night. However, the photovoltaic system generates electricity during the day but cannot provide electricity at night. Therefore, the design of this system takes into account the characteristics of rural electricity consumption, and achieves an effective balance between daytime and nighttime electricity consumption through the combination of centralized energy storage and mobile energy storage.

[0033] Specifically, household DC loads are electrical equipment (such as LED lighting, DC fans and other home appliances) that are directly connected to the distributed household photovoltaic system. By directly using the DC power generated by photovoltaic power generation, household DC loads can avoid power conversion losses and improve overall energy efficiency.

[0034] Specifically, the power router dynamically allocates electricity according to photovoltaic power generation and load demand. Photovoltaic power generation gives priority to meeting the household DC load. When power generation is insufficient, it will obtain power from the low-voltage DC distribution network; when power generation is high, the excess power will be sent to the low-voltage DC distribution network or the village-level centralized energy storage station.

[0035] Specifically, the low-voltage DC distribution network is used to distribute and transmit DC power. By adopting DC transmission, the inverter and rectification losses in traditional AC power transmission are reduced, thereby improving the power transmission efficiency and deeply matching the rural distributed energy scenario.

[0036] Specifically, the village-level centralized energy storage station is responsible for collecting, storing and managing excess electricity from distributed household photovoltaic systems. When photovoltaic power generation is insufficient, the energy storage station provides stable power for the load.

[0037] This solution avoids the high initial investment and complex maintenance requirements of each household installing an energy storage system independently through the use of village-level centralized energy storage stations, thereby reducing the overall cost and technical management difficulty. Improved energy efficiency. Village-level centralized energy storage stations can achieve optimal resource allocation and efficient energy utilization through unified power dispatching and management, reducing resource waste and equipment redundancy problems in decentralized energy storage systems. In addition, village-level centralized energy storage stations also enhance the overall safety of the system. Centrally managed energy storage systems can monitor and maintain equipment more effectively, reduce safety risks such as fires caused by energy storage systems, and reduce the difficulties of household users in management and operation.

[0038] This solution combines centralized energy storage with mobile energy storage to better manage the balance between photovoltaic power generation and electricity load, maximize the use of excess photovoltaic power, avoid voltage fluctuations and frequency instability caused by decentralized energy storage systems, and thus improve the stability and reliability of the regional power grid.

[0039] The village-level centralized energy storage station and low-voltage DC power distribution system of this solution can make the electric energy flow internally first, and the insufficient or excess part can interact with the AC network through the centralized grid connection point, so as to always maximize the local utilization of new energy. It also reduces the interaction with the power grid, reduces the impact on the power grid, and simplifies the power coordination between the power grid and users.

[0040] It should be noted that active energy storage loads include energy storage devices that are adjusted under specific needs, such as electric vehicle charging piles. These loads can flexibly adjust their operating time according to the status of power supply. Through flexible scheduling, active energy storage loads are charged during peak power generation periods and excess power is used for storage.

[0041] PCS. The power storage converter (PCS) is responsible for power conversion between DC and AC, managing the flow of power between the energy storage system and the grid. Mains, the auxiliary power source for the system.

[0042] The combination of centralized energy storage and mobile energy storage achieves the best results through dynamic power dispatch and reasonable resource allocation. As the main energy storage unit of the system, the centralized energy storage station is responsible for absorbing the excess power of the distributed household photovoltaic system and providing power support when photovoltaic power generation is insufficient, thereby balancing supply and demand and stabilizing the overall power supply of the system. Mobile energy storage loads (such as electric vehicle charging piles) directly use excess power during the peak period of photovoltaic power generation without having to store it in the centralized energy storage station first, which reduces unnecessary power conversion losses and improves power utilization efficiency.

[0043] The intelligent power router in the system will give priority to allocating excess power during the peak period of photovoltaic power generation to active energy storage loads to meet their immediate charging needs. When the needs of active energy storage loads have been met, the excess power will be transmitted to the centralized energy storage station through the low-voltage DC distribution network for storage, so as to be used for power supply when photovoltaic power generation is insufficient.

[0044] In the existing technology, rural "solar storage direct flexible" buildings adopt distributed photovoltaic and distributed energy storage solutions, and each household installs a separate energy storage system. This solution faces many problems such as high cost, complex maintenance, and safety risks. This solution overcomes the above challenges by combining centralized energy storage with mobile energy storage. The specific differences are: Cost reduction: The centralized energy storage station replaces the independent energy storage system for each household, reducing the high initial investment and maintenance costs required to install energy storage equipment for each household. At the same time, the centralized energy storage system can be built on a large scale, with lower unit costs. When the technology is upgraded, the equipment can be updated centrally to avoid the risk of early equipment depreciation.

[0045] Simplified management: Centralized energy storage stations are maintained and managed by village-level power management departments or professionals, eliminating the technical maintenance burden of distributed energy storage systems on ordinary households. Especially in rural areas where users lack technical background, centralized system management is more efficient and safer.

[0046] Improved safety: Centralized energy storage stations are located in independent facilities, avoiding the potential safety hazards of energy storage systems scattered across households and reducing the possibility of fire and electrical failures. In addition, centralized management can further improve the safety of the overall system through unified monitoring and safety protection measures.

[0047] Efficient resource utilization: The combination of centralized energy storage and mobile energy storage optimizes energy efficiency. Centralized energy storage stations can be flexibly dispatched according to electricity demand by storing excess electricity. Mobile energy storage loads (such as electric vehicle charging piles) can store electricity during the peak period of photovoltaic power generation, realizing dynamic allocation and utilization of energy, avoiding resource waste and redundancy problems caused by distributed layout in existing technologies.

[0048] Grid stability: Accessing the grid through a unified centralized energy storage station avoids the frequency instability and voltage fluctuation problems caused by the access of distributed energy storage systems to the grid. The centralized energy storage system can achieve two-way exchange of electricity through the energy storage converter (PCS), which not only benefits from transmitting electricity to the grid when there is excess photovoltaic power generation, but also can draw electricity from the grid when there is insufficient power generation, ensuring the continuous supply of rural electricity.

[0049] This solution overcomes many technical difficulties of existing technologies in rural electricity use scenarios through the innovative design of combining centralized energy storage and mobile energy storage: First, the existing technology of installing distributed energy storage systems for each household brings about high costs and complex maintenance problems, which are overcome in this system through the model of centralized energy storage at the village level, significantly reducing the installation and operation costs of the system.

[0050] Secondly, the safety hazards in the existing technology are resolved by centrally managing the energy storage system and separating it from residents’ homes, further improving the safety of the system.

[0051] This solution achieves efficient resource utilization and grid management that has not been proposed by existing technologies. By dynamically adjusting the energy storage load, the benefits of photovoltaic power generation are fully utilized and the challenges to grid frequency and voltage stability are reduced.

[0052] This working mode not only ensures the direct and efficient use of photovoltaic power generation, but also provides long-term, large-scale power regulation through centralized energy storage, while active energy storage loads achieve short-term, flexible load regulation, thus achieving efficient operation of the system under different load demands and optimal energy configuration.

[0053] The above specific embodiments are preferred embodiments of the present invention, and are not intended to limit the specific implementation scope of the present invention. The scope of the present invention includes but is not limited to the present specific embodiments. All equivalent changes made in accordance with the shape, structure, and method of the present invention are within the protection scope of the present invention.

Claims

1. The photovoltaic storage direct-flexible building system based on centralized energy storage is characterized by: It includes distributed household photovoltaic systems, household DC loads, power routers, low-voltage DC distribution networks, village-level centralized energy storage stations, active energy storage loads, energy storage inverters, and city power. Distributed household photovoltaic systems transmit electricity to and from village-level centralized energy storage stations through low-voltage DC distribution networks. Power routers dynamically adjust power flow based on real-time power generation and load conditions, giving priority to ensuring the power demand of the household's DC loads. When power generation is high, excess power is supplied to active energy storage loads for charging or stored in village-level centralized energy storage stations through low-voltage DC distribution networks. When power generation is insufficient, power is obtained from village-level centralized energy storage stations through low-voltage DC distribution networks. Village-level centralized energy storage stations and low-voltage DC distribution networks exchange power in both directions through energy storage inverters. When the village-level centralized energy storage station has sufficient power, excess power is fed back to the low-voltage DC distribution network through energy storage inverters. When the village-level centralized energy storage station has insufficient power, power is obtained from the low-voltage DC distribution network. By combining centralized energy storage with active energy storage, continuous power supply to household DC loads is ensured.

2. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 1 is characterized in that: The distributed household photovoltaic system power generation system is installed on the surface of an existing building, and the DC power generated by the system is used to provide power supply for the DC appliances of the users.

3. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 1 is characterized in that: The household DC load is an electrical device directly connected to the distributed household photovoltaic system. By directly using the DC power generated by photovoltaic power generation, the household DC load reduces the power conversion loss.

4. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 1 is characterized in that: The power router dynamically allocates power according to photovoltaic power generation and load demand.

5. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 4 is characterized in that: Photovoltaic power generation gives priority to meeting the household DC load. When power generation is insufficient, it will obtain electricity from the low-voltage DC distribution network. When power generation is excessive, the excess electricity will be sent to the low-voltage DC distribution network or the village-level centralized energy storage station.

6. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 1 is characterized in that: The low-voltage DC distribution network is used to distribute and transmit DC power. By adopting DC transmission, it deeply matches the rural distributed energy scenario.

7. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 1 is characterized in that: The village-level centralized energy storage station is responsible for collecting, storing and managing excess electricity from distributed household photovoltaic systems. When photovoltaic power generation is insufficient, the energy storage station provides stable power for the load.

8. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 1 is characterized in that: The active energy storage load includes energy storage equipment that is adjusted under specific needs, and the operating time is flexibly adjusted according to the status of power supply. Through flexible scheduling, the active energy storage load is charged during the peak power generation period and the excess electricity is stored.

9. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 1 is characterized in that: The energy storage converter is responsible for converting power between direct current and alternating current and managing the flow of power between the energy storage system and the power grid.

10. The photovoltaic storage direct-flexible building system based on centralized energy storage according to claim 1 is characterized in that: The combination of centralized energy storage and active energy storage is achieved through dynamic power dispatching and rational allocation of resources. The village-level centralized energy storage station, as the energy storage unit of the photovoltaic storage direct and flexible building system, is responsible for absorbing excess power from distributed household photovoltaic systems and providing power support when the distributed household photovoltaic systems generate insufficient power, thereby balancing supply and demand and stabilizing the overall power supply of the system.

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