Optical storage and charging micro-grid system

Abstract

The utility model provides a kind of optical storage fills microgrid system, including transformer, energy storage system, photovoltaic power generation system, charging system, anti-backflow monitoring device and station energy dispatching system.The input end of transformer is connected with power grid high-voltage line, and output provides alternating current low-voltage bus bar.Each set of energy storage system's energy storage converter is connected with alternating current low-voltage bus bar.The output end of photovoltaic inverter of photovoltaic power generation system is connected to alternating current low-voltage bus bar.Charging system is used to take electricity from alternating current low-voltage bus bar, and export electric energy to external device.Anti-backflow monitoring device includes first monitoring unit and second monitoring unit.Station energy dispatching system is connected with energy storage system, photovoltaic power generation system and anti-backflow monitoring device in communication;Among them, station energy dispatching system is configured as: when first monitoring unit monitors that total load power exceeds the rated capacity of transformer, close the anti-backflow function of second monitoring unit, and control energy storage converter and photovoltaic inverter output power to alternating current low-voltage bus bar.

Description

Technical Field

[0001] This utility model relates to the field of photovoltaic energy storage charging station technology, and more specifically to a photovoltaic energy storage charging microgrid system. Background Technology

[0002] Integrated photovoltaic, energy storage, and charging power stations represent a new energy utilization model. Currently, there is a significant demand for charging new energy vehicles in industrial and commercial parks, highway service areas, and scenic area parking lots. However, high-power fast charging can negatively impact the quality of existing electricity used for production and business operations, and electricity costs for industrial and commercial users are relatively high. Furthermore, it requires expanding transformer capacity to meet the demands of high-power charging piles, which incurs substantial costs.

[0003] Existing new energy supercharging stations, photovoltaic power stations, and industrial and commercial energy storage stations on the market are all single-function products. Integrated photovoltaic-storage-charging power stations can achieve certain social and economic benefits by formulating reasonable energy storage configuration and operation strategies and using time-of-use pricing to uniformly dispatch the energy storage system, charging piles, and photovoltaic power generation within the power station. They have huge market potential and development space.

[0004] Therefore, there is a need to provide a photovoltaic-storage-charging microgrid system to at least partially solve the above problems. Utility Model Content

[0005] The utility model description section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This utility model description section is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To at least partially solve the above problems, this utility model provides a photovoltaic-storage-charging microgrid system, characterized in that it includes:

[0007] A transformer whose input end is connected to the high-voltage line of the power grid and whose output end provides an AC low-voltage bus.

[0008] At least one energy storage system, each of the energy storage systems including an energy storage converter connected to the AC low-voltage bus;

[0009] A photovoltaic power generation system includes a photovoltaic inverter, the output of which is connected to the AC low-voltage busbar;

[0010] A charging system is used to draw power from the AC low-voltage bus and output electrical energy to external devices;

[0011] Backflow prevention monitoring device, including:

[0012] The first monitoring unit is located on the output side of the transformer and is used to monitor the total load power on the output side of the transformer.

[0013] The second monitoring unit is located between the photovoltaic power generation system and the charging system;

[0014] The power station energy dispatching system is communicatively connected to the energy storage system, the photovoltaic power generation system, and the anti-reverse current monitoring device. The power station energy dispatching system is configured such that when the first monitoring unit detects that the total load power exceeds the rated capacity of the transformer, the power station energy dispatching system shuts down the anti-reverse current function of the second monitoring unit and controls the output power of the energy storage converter and the photovoltaic inverter to the AC low-voltage bus.

[0015] According to this plan, the photovoltaic-storage-charging microgrid system can simultaneously ensure a stable power supply for daily production and operation, significantly reduce electricity costs, and meet the needs of building new high-power new energy vehicle charging stations without the need for additional transformer expansion.

[0016] Optionally, the duration of the output power of the energy storage converter and the photovoltaic inverter shall not exceed the upper limit of the single continuous working time of the unstable load connected to the AC low-voltage bus.

[0017] The unstable load is an electrical device whose power fluctuation range is greater than ±10% of the rated power.

[0018] Optionally, the power station energy dispatching system is configured to control the energy storage converter to switch to off-grid mode when the power grid fails, so as to supply power to the AC low-voltage bus.

[0019] Optionally, in the off-grid mode, the power dispatching system of the power station prioritizes supplying power to stable loads;

[0020] The stable load is an electrical device with a power fluctuation range of ≤ ±10% of the rated power.

[0021] Optionally, when the first monitoring unit detects that the mains power has been restored, the station energy dispatching system controls the energy storage converter to switch to grid-connected mode within 20ms.

[0022] Optionally, the photovoltaic-storage-charging microgrid system further includes a sub-control distribution box. The output terminal of the photovoltaic inverter and the charging system are connected to the AC low-voltage bus through the sub-control distribution box. A circuit breaker is installed in the sub-control distribution box to control its connection and disconnection with the bus.

[0023] Optionally, the energy storage system includes multiple independent energy storage units, and the site energy dispatching system performs unified power allocation of the multiple energy storage units through a communication network.

[0024] Optionally, the power station energy dispatching system is configured as follows:

[0025] During periods of low electricity prices set by the power grid supplier, the energy storage converter is controlled to store electrical energy in the energy storage unit;

[0026] During periods of high electricity prices set by the power grid supplier, the energy storage converter is controlled to invert the energy from the energy storage unit into AC power to supply the load.

[0027] Optionally, the photovoltaic-storage-charging microgrid system also includes a management cloud platform, which is communicatively connected to the power station energy dispatching system to realize remote monitoring, cloud control, and charging fee payment functions.

[0028] Optionally, the electricity generated by the photovoltaic power generation system is preferentially supplied to the charging system, and any surplus electricity is stored in the energy storage unit. Attached Figure Description

[0029] The following drawings, which illustrate embodiments of the present invention, are incorporated herein as part of the present invention for understanding the invention. The drawings show embodiments of the present invention and their descriptions, serving to explain the principles of the present invention. In the drawings,

[0030] Figure 1 A schematic diagram of the charging and discharging of an energy storage system according to a preferred embodiment of this utility model;

[0031] Figure 2 This is a schematic diagram of a photovoltaic power generation and charging system according to a preferred embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of a photovoltaic-storage-charging microgrid system according to a preferred embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of an example of a photovoltaic, energy storage, and charging integrated power station according to a preferred embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures

[0035] 10: Transformer

[0036] 11: AC low-voltage busbar

[0037] 20: Energy Storage System

[0038] 201: First Energy Storage System

[0039] 202: Second Energy Storage System

[0040] 203: Third Energy Storage System

[0041] 21: Energy Storage Converter

[0042] 22: Battery Pack

[0043] 23: Battery Management System

[0044] 24: Energy Management System

[0045] 30: Photovoltaic power generation system

[0046] 31: Photovoltaic Inverter

[0047] 32: Photovoltaic panels

[0048] 40: Charging System

[0049] 41: External Equipment / New Energy Vehicles

[0050] 42: DC charging gun

[0051] 43: AC charging gun

[0052] 50: Backflow Prevention Monitoring Device

[0053] 51: First Monitoring Unit

[0054] 52: Second Monitoring Unit

[0055] 60: Station Energy Dispatch System

[0056] 70: Sub-control distribution box

[0057] 71: Circuit breaker

[0058] 80: High-voltage power lines

[0059] 90: Stable load

[0060] 91: Unstable load

[0061] 100: Management Cloud Platform

[0062] 110: Local Area Network Detailed Implementation

[0063] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid confusion with embodiments of the present invention.

[0064] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0065] In this document, ordinal numbers such as "first" and "second" used in this invention are merely identifiers and do not have any other meaning, such as a specific order. Moreover, for example, the term "first component" does not imply the existence of "second component," and the term "second component" does not imply the existence of "first component."

[0066] In this article, terms such as "up," "down," "front," "back," "left," and "right" are used only to indicate the relative positional relationship between related parts, rather than to define the absolute position of these related parts.

[0067] In this document, terms such as “equal” and “same” are not strict mathematical and / or geometric limitations, but also include errors that are understandable to those skilled in the art and permissible in manufacturing or use.

[0068] Unless otherwise stated, the numerical ranges in this document include not only the entire range within its two endpoints, but also the subranges contained therein.

[0069] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the present invention is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art.

[0070] This utility model provides a photovoltaic-storage-charging microgrid system, aiming to effectively solve the key technical challenges of ensuring stable power supply for daily production and operation in industrial and commercial parks, significantly reducing electricity costs, and meeting the needs of newly built high-power new energy vehicle charging stations without the need for additional transformer capacity expansion. The photovoltaic-storage-charging microgrid system provided by this solution integrates photovoltaic power generation, new energy vehicle charging, energy storage, peak shaving and valley filling for industrial and commercial electricity, and capacity expansion of the virtual transformer 10 for industrial and commercial electricity. It constructs an intelligent microgrid system integrating power generation, energy storage, charging, and power consumption, realizing efficient utilization of electricity, peak shaving and valley filling arbitrage to reduce electricity costs, virtual transformer capacity expansion, and off-grid emergency power supply, bringing significant economic and social benefits to industrial and commercial users.

[0071] The photovoltaic-storage-charging microgrid system includes a transformer 10, an energy storage system 20, a photovoltaic power generation system 30, a charging system 40, an anti-reverse current monitoring device 50, and a power station energy dispatching system 60.

[0072] Transformer 10 is used to step down the high-voltage grid power to a usable voltage, supporting the stable operation of the microgrid. As the interface between the system and the grid, transformer 10 connects to the high-voltage grid line 80, such as a 10kV AC bus, at its input end, while providing low-voltage AC power available to industrial and commercial facilities at its output end, forming a three-phase four-wire AC 400V bus, providing basic power support and stable operation guarantee for the entire microgrid.

[0073] The energy storage system 20 can be configured with multiple independent energy storage units, and each energy storage system 20 includes an energy storage converter 21. The energy storage converter 21 is connected to the AC low-voltage bus 11 and is used for the storage and release of electrical energy: during charging, it converts AC power into DC power for storage; during discharging, it inverts DC power into AC power to supply the load.

[0074] Each energy storage system 20 also includes a battery pack 22, a battery management system 23, and an energy management system 24. The battery pack 22 stores electrical energy, serving as the system's energy storage unit. Optionally, multiple battery packs 22 may be configured. The battery management system 23 is responsible for real-time reading of battery status (such as voltage, temperature, and SOC), calculating battery parameters, and feeding this information back to the energy management system 24 to control the charging and discharging process. The energy management system 24, based on preset strategies or real-time commands, combined with grid parameters and battery status, precisely issues charging and discharging commands and controls the power output of the energy storage converter 21, ensuring the entire process is efficient and safe. The energy storage converter 21 works collaboratively with the battery pack 22, battery management system 23, and energy management system 24: the energy management system 24 obtains battery status through the battery management system 23 and directly controls the power output of the energy storage converter 21, achieving efficient energy management. Multiple energy storage units can be uniformly allocated by the energy management system 24 through the local area network 110, enabling flexible configuration of capacity and power. They can also operate independently according to demand. This design allows the system to flexibly configure the capacity and power of the energy storage system 20 according to the actual power load characteristics during the allocation and storage phase, and has high scalability.

[0075] The photovoltaic power generation system 30 includes a photovoltaic inverter 31 and photovoltaic panels 32. The output of the photovoltaic inverter 31 is connected to the AC low-voltage bus 11 to convert the DC power generated by the photovoltaic panels 32 into AC power that conforms to grid standards. The output of the photovoltaic inverter 31 is typically connected to the AC 400V bus via a sub-control distribution box 70 to inject clean energy into the microgrid.

[0076] The charging system 40 draws power from the AC low-voltage bus 11 and outputs electrical energy to the external device 41. Optionally, the external device 41 is a new energy vehicle 41, and the charging system 40 includes a DC charging gun 42 and an AC charging gun 43 to support fast charging of the new energy vehicle 41.

[0077] The anti-reverse current monitoring device 50 is crucial for maintaining the independence of the microgrid and the security of the grid. The anti-reverse current monitoring device 50 includes a first monitoring unit 51 and a second monitoring unit 52. Optionally, the first monitoring unit 51 and the second monitoring unit 52 are anti-reverse current meters.

[0078] The first monitoring unit 51 is located on the output side of the transformer 10, adjacent to the grid connection point. The first monitoring unit 51 is used to monitor the total load power (such as voltage, current, and frequency) on the output side of the transformer 10 and to prevent electrical energy from flowing back into the grid. The first monitoring unit 51 provides a basis for precise power regulation by feeding back load information to the control system in real time.

[0079] The second monitoring unit 52 is located between the photovoltaic power generation system 30 and the charging system 40 to control the return flow of electrical energy and ensure the independence of the microgrid. Optionally, the second monitoring unit 52 is integrated into the sub-control distribution box 70 connecting the photovoltaic power generation system 30 and the charging system 40. The second monitoring unit 52 works in conjunction with the first monitoring unit 51 to achieve more refined power management.

[0080] The output of the photovoltaic inverter 31 and the charging system 40 are connected to the AC low-voltage busbar 11 via a sub-control distribution box 70. A circuit breaker 71 is installed in the sub-control distribution box 70 to control the connection and disconnection between the photovoltaic power generation system 30 and the charging system 40 and the busbar. A second monitoring unit 52 is integrated within the sub-control distribution box 70 to prevent backflow of electrical energy into the grid and to monitor the direction of electrical energy flow in real time. The power station energy dispatching system 60 prioritizes supplying the electricity generated by the photovoltaic power generation system 40 to the charging system 40 via the sub-control distribution box 70, storing any surplus in the energy storage unit.

[0081] The power station energy dispatching system 60 is the intelligent hub of the entire microgrid, connecting and uniformly dispatching all subsystems through a communication network. Its core functional logic is as follows: First, the power station energy dispatching system 60 implements the crucial virtual transformer 10 capacity expansion function. When the first monitoring unit 51 detects that the total load power on the AC low-voltage bus 11 (usually caused by the superposition of stable load 90 and unstable load 91) exceeds the rated capacity of the transformer 10, the power station energy dispatching system 60 will immediately activate the capacity expansion strategy.

[0082] The expansion strategy of the power station energy dispatch system 60 is as follows: The anti-reverse flow function of the second monitoring unit 52 is disabled to allow the branch to output power. The system reads the parameters of the first monitoring unit 51 and the second monitoring unit 52 at high speed, and precisely coordinates and controls the output power of all energy storage converters 21 and photovoltaic inverters 31 to the bus. At this time, the total available power of the microgrid instantly increases to the sum of the rated power of transformer 10, the output power of all energy storage systems 20, and the output power of photovoltaic inverters 31, effectively supporting short-term high-power demands (such as the startup of high-power charging piles or yard equipment) without the need for actual expansion of transformer 10. This function is specifically designed for high power demands (such as the startup of high-power charging piles or yard equipment) without the need for actual expansion of transformer 10. This function is specifically designed for the aforementioned unstable load 91. The system precisely controls the output power duration (not exceeding the upper limit of the single continuous working time of unstable load 91) by real-time monitoring of the parameters of the first monitoring unit 51, ensuring safety and stability, while relying on the first monitoring unit 51 to strictly prevent power from flowing back to the grid. Figure 3 The diagram illustrates a photovoltaic-storage-charging microgrid system, with a complete microgrid architecture under the unified management of the site energy dispatch system 60. This system connects and controls multiple energy storage systems 20, photovoltaic inverters 31, and charging guns, and reads anti-reverse current meter parameters. Remote monitoring and payment are achieved through the management cloud platform 100.

[0083] In this scheme, the unstable load 91 is an electrical device with a power fluctuation range > ±10% of the rated power. The unstable load 91 has a large power demand and a short demand period, which can easily lead to transformer 10 overload. Optionally, the maximum continuous working time of the unstable load 91 at one time is 2 hours. The power station energy dispatching system 60 accurately controls the duration of output power by reading the parameters of the first monitoring unit 51 in real time, ensuring system stability and safety.

[0084] In this scheme, the power station energy dispatch system 60 has the capability of off-grid operation and seamless switching. When the first monitoring unit 51 cannot detect mains power parameters (i.e., the grid is down), the system immediately triggers the off-grid mode by reading the first monitoring unit 51 at high speed when no mains power parameters (such as voltage or frequency abnormalities) are detected. In this mode, the energy storage converter 21 switches to off-grid status and independently outputs AC power to supply the bus, maintaining the operation of the microgrid and ensuring the continuity of power supply to critical loads.

[0085] To optimize the allocation of limited power, the system implements a power supply priority strategy: In off-grid mode, the power dispatch system 60 prioritizes stable loads 90 over unstable loads 91, and unstable loads 91 are prioritized over loads under the sub-control distribution box 70. Specifically, stable loads 90 (such as everyday office equipment) with power fluctuations ≤ ±10% of rated power are prioritized for power supply, for example, by disconnecting unstable loads 91 and the loads of the charging system 40 (such as loads under the sub-control distribution box 70). This priority strategy is based on real-time analysis of load demand by the power dispatch system 60 to optimize resource allocation and ensure core functions when power is limited.

[0086] When the first monitoring unit 51 detects the restoration of mains power (e.g., by reading grid parameters), the power station energy dispatching system 60 controls the energy storage converter 21 to switch to grid-connected mode within 20ms. Specifically, the system controls the energy storage converter 21 to adjust its output parameters (voltage, frequency) to synchronize with the mains power, and achieves seamless switching through high-speed communication, avoiding conflicts between the microgrid and the grid, and greatly improving system reliability and response speed.

[0087] In this scheme, the power station energy dispatch system 60 implements an intelligent time-of-use pricing-based charging and discharging strategy to maximize economic benefits (peak shaving and valley filling). The power station energy dispatch system 60 is configured to: during low-price periods set by the grid power supplier, control the energy storage converter 21 to store electrical energy in the energy storage unit. Optionally, the low-price period is the nighttime period. Specifically, controlling the energy storage converter 21 to store electrical energy in the energy storage unit involves: drawing power from the grid, stepping it down through the transformer 10, and then converting it to DC power via the energy storage converter 21 for storage in the battery pack 22. The power station energy dispatch system 60 is also configured to: during high-price periods set by the grid power supplier, control the energy storage converter 21 to invert the electrical energy from the energy storage unit into AC power to supply the load. Optionally, the low-price period is the daytime period. This strategy utilizes the price difference to achieve peak shaving and valley filling arbitrage, reducing electricity costs for industrial and commercial users. The power station energy dispatch system 60 ensures that electrical energy does not flow back to the grid through the anti-backflow monitoring device 50 (such as the first monitoring unit 51), and optimizes economic benefits by adjusting the power in real time.

[0088] In this scheme, the power dispatch system 60 controls the energy storage system 20 to perform power replenishment operations during the period when the stable load 90 is at its lowest daily power demand. For example, the period of lowest daily power demand is the nighttime low-load period. This avoids conflicts with peak electricity consumption, ensures that the power replenishment process does not affect daily power supply, and optimizes the charging and discharging sequence through the energy management system 24 to maximize system efficiency and benefits.

[0089] In this scheme, the system prioritizes the use of photovoltaic power. The station energy dispatch system 60, through the sub-control distribution box 70 and the second monitoring unit 52, prioritizes directly supplying the clean power generated by the photovoltaic panels 32 to the charging system 40 (such as DC charging gun 42 or AC charging gun 43). If there is no demand for charging of new energy vehicles 41 or if there is surplus photovoltaic power generation, the surplus power is directed to the energy storage system 20 for storage through the sub-control distribution box 70, realizing the efficient utilization and storage of clean energy, reducing dependence on the power grid and improving environmental benefits. The power generated by the photovoltaic power generation system 30 is prioritized for supply to the charging system 40 (such as directly for DC or AC charging gun 43 through the sub-control distribution box 70). When there is no vehicle charging, the photovoltaic power is supplied to the energy storage system 20 for charging through the sub-control distribution box 70. This logic is controlled by the station energy dispatch system 60 through the second monitoring unit 52 to ensure the priority supply of photovoltaic power generation.

[0090] The photovoltaic-storage-charging microgrid system also includes a management cloud platform 100. As an extension layer of the system, the management cloud platform 100 is closely connected to the site energy dispatch system 60, providing users and maintenance personnel with remote monitoring, cloud control, and charging fee payment functions. Users can conveniently complete charging payments through the platform, while maintenance personnel can remotely view equipment status and adjust system strategy parameters, improving system manageability and user experience.

[0091] Figure 1 The system includes two energy storage systems 20: a first energy storage system 201 and a second energy storage system 202. During nighttime periods of low electricity prices, the high-voltage grid line 80 (10kV AC busbar) connects to the factory substation, and the power is output (three-phase four-wire AC 400V) via transformer 10 through the low-voltage AC busbar 11. The first monitoring unit 51 acquires detailed voltage, current, and frequency information from the low-voltage AC busbar 11. The outdoor cabinet energy storage converter 21 converts the AC power into DC power, which is then stored in the battery pack 22. The energy management system 24 is responsible for issuing charging and discharging commands, controlling charging and discharging power, and reading grid parameters and battery parameters. After reading and calculating the battery status, the battery management system 23 feeds back the relevant information to the energy management system 24 to control the power of the energy storage converter 21, ultimately completing the charging process.

[0092] During peak electricity price periods in the daytime, the energy management system 24 presets a discharge period. During this period, the energy management system 24 sends discharge commands to the battery management system 23 and power commands to the energy storage converter 21. After reading the grid parameters, the energy storage converter 21 inverts the DC power output from the battery pack 22 into AC power consistent with the grid parameters, supplying the stable load 90 of the microgrid. The power of the stable load 90 is fed back to the energy management system 24 through the first monitoring unit 51. The energy management system 24 controls and adjusts the output power of the energy storage converter 21 in real time to ensure that electricity does not flow back to the grid. By utilizing the difference between high and low electricity prices, peak shaving and valley filling arbitrage are achieved, creating economic value.

[0093] Among them, the first energy storage system 201 and the second energy storage system 202 can be uniformly dispatched by the energy management system 24 through the local area network 110, or they can work independently; in the design of the energy storage and distribution stage, the capacity and power of the energy storage system 20 can be flexibly configured according to the electricity demand.

[0094] like Figure 2 As shown, the DC power generated by the photovoltaic panel 32 is converted into AC power by the inverter and then sent to the sub-control distribution box 70, which prioritizes the use of the charging gun; if there is surplus power, it is stored in the third energy storage system 203.

[0095] The photovoltaic panel 32 begins generating electricity after the sunlight reaches its rated intensity. The direct current (DC) is collected by the photovoltaic inverter 31, converted into alternating current (AC), and then transmitted to the sub-control distribution box 70. This AC power is primarily used by the DC charging gun 42 and the AC charging gun 43 to charge the new energy vehicle 41. When there is no need to charge the new energy vehicle 41, the electrical energy output from the photovoltaic inverter 31 to the sub-control distribution box 70 is transmitted to the outdoor energy storage cabinet for charging, thus achieving clean energy storage.

[0096] During periods of high electricity prices, if there is a charging demand for the new energy vehicle 41, the energy management system 24 will control the energy storage converter 21 to output power to the charging gun, releasing the stored electrical energy to the new energy vehicle 41. Both the energy storage converter 21 and the photovoltaic inverter 31 can automatically read the grid parameters and adjust the AC power parameters of their inverter output to be consistent with the grid to ensure power supply stability.

[0097] A second monitoring unit 52 is installed in the sub-control distribution box 70, which can control whether the electrical energy output by the energy storage converter 21 and the photovoltaic inverter 31 flows back to the AC grid high-voltage line 80, and can also control the disconnection and connection operations of the circuit breaker 71.

[0098] When integrating the energy storage system 20 and the photovoltaic power generation system 30 into the same power grid, in order to realize the capacity expansion function of the virtual transformer 10 for industrial and commercial power consumption, off-grid power supply, and higher economic value, it is necessary to uniformly allocate the two functional systems and realize cloud control, remote monitoring, and online payment for charging fees. Based on the above two systems, an additional site energy dispatching system 60 and management cloud platform 100 are added.

[0099] Figure 3 The complete microgrid architecture under the unified management of the power station energy dispatch system 60 is shown. The power station energy dispatch system 60 connects and controls multiple energy storage systems 20, photovoltaic inverters 31, and charging guns, and reads anti-reverse current meter parameters, realizing remote monitoring and payment functions through the management cloud platform 100.

[0100] The power station energy dispatch system 60 can simultaneously control the first energy storage system 201, the second energy storage system 202, the third energy storage system 203, the photovoltaic inverter 31, and the charging gun, and can synchronously read the grid parameters of the first monitoring unit 51 and the second monitoring unit 52. The system is connected to the management cloud platform 100 to realize functions such as remote monitoring, cloud control, and vehicle charging payment, forming a microgrid integrating power generation, energy storage, charging, and power consumption. This microgrid is an independent grid circuit that does not supply power to the national grid; its power generation and discharge are all consumed within the microgrid.

[0101] When the unstable load 91 is connected to the AC low-voltage bus 11, its power demand is high and its time demand is short, which may exceed the rated power of the transformer 10 for a short period of time. At this time, the power station energy dispatch system 60 will read the parameters of the first monitoring unit 51 and the second monitoring unit 52 at high speed, compare them with the rated power of the transformer 10, and accurately control the output power of the first energy storage system 201, the second energy storage system 202 and the third energy storage system 203, while controlling the output power of the photovoltaic inverter 31. At this time, the anti-reverse current function of the second energy storage system 202 is in the off state, and only the grid parameters of the first energy storage system 201 are used to expand the available power of the entire microgrid to the sum of the rated power of the transformer 10, the first energy storage system 201, the second energy storage system 202, the third energy storage system 203 and the output power of the photovoltaic inverter 31, realizing the expansion of the virtual transformer 10 for short-term power consumption, with a maximum support time of 2 hours. In a specific embodiment, the priority of the stable load 90 is higher than that of the unstable load 91, and the priority of the unstable load 91 is higher than that of the load under the sub-control distribution box 70.

[0102] After a grid outage, the system forms an off-grid microgrid. At this time, the station energy dispatch system 60 rapidly reads the parameters from the first monitoring unit 51 and controls the energy storage inverters in the three energy storage systems 20 (201 / 202 / 203) to switch to off-grid mode. The power demand received by the first monitoring unit 51 at this time is equal to the output power of the energy storage system 20. When the first monitoring unit 51 detects mains power parameters, the station energy dispatch system 60 controls the energy storage inverters in the three energy storage systems 20 (201 / 202 / 203) to adjust their output parameters to match the mains power, and switches the entire microgrid back to grid-connected mode within 20ms. In a specific embodiment, in off-grid mode, stable load 90 is prioritized, while unstable load 91 and loads under the sub-control distribution box 70 are disconnected.

[0103] In the independent DC charging gun 42 and AC charging gun 43 operating modes, revenue comes solely from service fees. Adding the third energy storage system 203 reduces the demand on transformer 10 capacity during peak daytime electricity consumption of the stable load 90 for charging new energy vehicles 41. When uniformly scheduling the two functional modules, if there is a surplus in the output power of the third energy storage system 203 and the photovoltaic inverter 31, this surplus can be supplied to the stable load 90 to achieve optimal energy utilization and maximize revenue. All power replenishment operations of the energy storage system 20 are performed during the period when the stable load 90 has the lowest daily power demand.

[0104] This utility model provides a microgrid system that integrates core functions such as photovoltaic power generation, charging of new energy vehicles (41), energy storage, peak shaving and valley filling for industrial and commercial electricity, and capacity expansion of the virtual transformer (10) for industrial and commercial electricity. By expanding the capacity of the energy storage system (20), a certain number of high-power new energy vehicle (41) charging piles or short-term high-power load devices can be added without additional capacity expansion of the transformer (10). The system combines key parameters such as the grid's time-of-use pricing policy, the rated capacity of the transformer (10), and the charging standards for new energy charging services to rationally configure the capacity of the energy storage system (20) and design an appropriate microgrid dispatch strategy. This achieves integrated operation of the originally independent photovoltaic power generation system (30) and energy storage system (20), making the overall revenue of the power station exceed the sum of the revenue from the independent operation of the two systems. Furthermore, the system equipment adopts a centralized physical layout, integrating all core equipment in the same site, maximizing land resource conservation.

[0105] To verify the actual effectiveness of this invention, a system was constructed in a factory in Dongguan. Figure 4 The example shown is a photovoltaic, energy storage, and charging integrated power station.

[0106] The power station is equipped with: a 650kW available capacity transformer 10, a peak power consumption capacity of 250-350kW for the office building (stable load 90), a temporary power consumption capacity of 170-200kW for the storage yard (unstable load 91), a 15kW photovoltaic power generation capacity, multiple energy storage systems 20 with specifications of 216kWh / 105kW (shown in the diagram), and a total of 136kW of charging power for new energy vehicles 41. The system is equipped with a power station energy dispatch system 60 to uniformly manage all equipment, an outdoor cabinet EMS cloud platform to ensure energy storage security, and an integrated charging payment platform.

[0107] Actual operation demonstrates that the power station successfully achieved all designed functions: efficiently charging the energy storage system 20 during off-peak hours at night; discharging the stored energy during peak daytime hours, significantly reducing electricity costs; when the combined load of the office building and storage yard may exceed the capacity of the transformer 10, the energy storage system 20 and the photovoltaic system work together to achieve virtual capacity expansion, ensuring power supply continuity without requiring any modifications to the transformer 10; in the event of a grid failure, the system quickly switches to off-grid mode, prioritizing stable power supply to the office building; photovoltaic power generation prioritizes charging needs, with surplus energy stored in the energy storage battery; users can conveniently pay charging fees through the management cloud platform 100, and maintenance personnel can remotely monitor the entire system status. This embodiment fully verifies that the photovoltaic-storage-charging microgrid system described in this invention achieves multi-functional integration, improves economic efficiency, and ensures power supply reliability.

[0108] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of the invention. Terms such as “set” appearing herein can refer to either a component being directly attached to another component or a component being attached to another component via an intermediary. A feature described in one embodiment may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0109] This utility model has been described through the above embodiments. However, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this utility model to the described embodiments. Those skilled in the art will understand that many more variations and modifications can be made based on the teachings of this utility model, and all such variations and modifications fall within the scope of protection claimed by this utility model.

Claims

1. A photovoltaic-storage-charging microgrid system, characterized in that, include: A transformer whose input end is connected to the high-voltage line of the power grid and whose output end provides an AC low-voltage bus. At least one energy storage system, each of the energy storage systems including an energy storage converter connected to the AC low-voltage bus; A photovoltaic power generation system includes a photovoltaic inverter, the output of which is connected to the AC low-voltage busbar; A charging system is used to draw power from the AC low-voltage bus and output electrical energy to external devices; Backflow prevention monitoring device, including: The first monitoring unit is located on the output side of the transformer and is used to monitor the total load power on the output side of the transformer. The second monitoring unit is located between the photovoltaic power generation system and the charging system; The power station energy dispatching system is communicatively connected to the energy storage system, the photovoltaic power generation system, and the anti-reverse current monitoring device. The power station energy dispatching system is configured such that when the first monitoring unit detects that the total load power exceeds the rated capacity of the transformer, the power station energy dispatching system shuts down the anti-reverse current function of the second monitoring unit and controls the output power of the energy storage converter and the photovoltaic inverter to the AC low-voltage bus.

2. The photovoltaic-storage-charging microgrid system according to claim 1, characterized in that, The duration of the output power of the energy storage converter and the photovoltaic inverter shall not exceed the upper limit of the single continuous working time of the unstable load connected to the AC low-voltage bus. The unstable load is an electrical device whose power fluctuation range is greater than ±10% of the rated power.

3. The photovoltaic-storage-charging microgrid system according to claim 1, characterized in that, The power station energy dispatch system is configured to control the energy storage converter to switch to off-grid mode when the power grid fails, so as to supply power to the AC low-voltage bus.

4. The photovoltaic-storage-charging microgrid system according to claim 3, characterized in that, In the off-grid mode, the power dispatch system of the power station prioritizes supplying power to stable loads; The stable load is an electrical device with a power fluctuation range of ≤ ±10% of the rated power.

5. The photovoltaic-storage-charging microgrid system according to claim 3, characterized in that, When the first monitoring unit detects that the mains power has been restored, the power dispatching system of the station controls the energy storage converter to switch to grid-connected mode within 20ms.

6. The photovoltaic-storage-charging microgrid system according to claim 1, characterized in that, The photovoltaic-storage-charging microgrid system also includes a sub-control distribution box. The output terminal of the photovoltaic inverter and the charging system are connected to the AC low-voltage bus through the sub-control distribution box. The sub-control distribution box is equipped with a circuit breaker to control its connection and disconnection with the bus.

7. The photovoltaic-storage-charging microgrid system according to claim 1, characterized in that, The energy storage system includes multiple independent energy storage units, and the site energy dispatching system performs unified power allocation for the multiple energy storage units through a communication network.

8. The photovoltaic-storage-charging microgrid system according to claim 1, characterized in that, The energy dispatch system for the power station is configured as follows: During periods of low electricity prices set by the power grid supplier, the energy storage converter is controlled to store electrical energy in the energy storage unit; During periods of high electricity prices set by the power grid supplier, the energy storage converter is controlled to invert the energy from the energy storage unit into AC power to supply the load.

9. The photovoltaic-storage-charging microgrid system according to claim 1, characterized in that, The photovoltaic-storage-charging microgrid system also includes a management cloud platform, which is communicatively connected to the power station energy dispatch system to realize remote monitoring, cloud control, and charging fee payment functions.

10. The photovoltaic-storage-charging microgrid system according to claim 1, characterized in that, The electricity generated by the photovoltaic power generation system is preferentially supplied to the charging system, and any surplus electricity is stored in the energy storage unit.

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