A photovoltaic power supply system, a photovoltaic power supply method, and a building energy storage power supply system

Abstract

This invention discloses a photovoltaic power supply system, a photovoltaic power supply method, and a building energy storage power supply system, comprising: a photovoltaic power generation unit, an energy storage unit, an inverter, a user load power monitoring unit, and an anti-reverse current monitoring device; the AC side of the inverter is connected in parallel to the power grid and the user load; the anti-reverse current monitoring device includes an anti-reverse current monitoring unit and an energy management control unit; in the surplus power grid connection mode, the energy management control unit dynamically coordinates the energy matching between the photovoltaic power generation unit, the energy storage unit, the power grid, and the user load, and automatically allocates power according to a preset priority; in the surplus power grid disconnection mode, the energy management control unit monitors the net power of the power grid in real time, and adjusts the output power of the inverter to maintain the net power of the power grid in the grid at zero or a positive value. This invention achieves optimal energy matching between photovoltaic power generation, energy storage, the power grid, and the user load through the dynamic coordination of the energy management control unit.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation technology, specifically to a photovoltaic power supply system, a photovoltaic power supply method, and a building energy storage power supply system. Background Technology

[0002] Building energy storage power supply systems refer to photovoltaic power generation devices installed on the roof of buildings. These devices directly convert sunlight into direct current (DC) through photovoltaic modules, which is then converted into alternating current (AC) by an inverter, for the building's own use or fed into the power grid.

[0003] Traditional photovoltaic power supply systems often only have simple power generation and supply functions, lacking effective energy management and coordination mechanisms. They cannot flexibly allocate energy according to user load demand, photovoltaic output, and grid status, resulting in low energy utilization and even the possibility of reverse power flow to the grid, affecting the safe and stable operation of the grid. Summary of the Invention

[0004] In view of this, the present invention provides a photovoltaic power supply system, a photovoltaic power supply method, and a building energy storage power supply system to solve the problem that traditional photovoltaic power supply systems cannot flexibly allocate energy according to user load demand, photovoltaic output, and grid status.

[0005] In a first aspect, the present invention provides a photovoltaic power supply system, comprising: Photovoltaic power generation unit with DC output terminal; Energy storage unit with charging and discharging terminals; Battery management system; The inverter has a photovoltaic DC input terminal and an energy storage DC input terminal on its DC side. The photovoltaic DC input terminal is electrically connected to the DC output terminal of the photovoltaic power generation unit, and the energy storage DC input terminal is electrically connected to the charging and discharging terminal of the energy storage unit. The AC side of the inverter is connected in parallel to the power grid and the user load. User load power monitoring unit, used to monitor user load power; The backflow prevention monitoring device includes a backflow prevention monitoring unit and an energy management control unit. The current sampling terminal of the backflow prevention monitoring unit is installed at the power grid inlet, and the signal output terminal of the backflow prevention monitoring unit is connected to the energy management control unit. The backflow prevention monitoring unit is used to collect current information from the power grid inlet. The energy management control unit is communicatively connected to the backflow prevention monitoring unit, the inverter, the energy storage unit, and the user load power monitoring unit. The photovoltaic power supply system operates in two modes: surplus power fed into the grid and surplus power not fed into the grid. In the surplus power grid connection mode, the energy management control unit receives the net power of the grid incoming line reported by the anti-reverse current monitoring unit, the photovoltaic output reported by the inverter, the energy storage unit status reported by the battery management system, and the user load power reported by the user load power monitoring unit. It dynamically coordinates the energy matching between the photovoltaic power generation unit, the energy storage unit, the grid, and the user load, and automatically allocates power according to a preset priority. The energy management control unit executes the following energy allocation logic: photovoltaic power generation is prioritized for user load use; when the user load exceeds the photovoltaic output, the power gap is supplemented by the energy storage unit discharging; if the energy storage unit's state of charge does not meet the discharge conditions, the grid supplies power; when the user load is less than the photovoltaic output, surplus power is prioritized for charging the energy storage unit; after the energy storage unit is fully charged or reaches its charging limit, the remaining power is fed back into the grid. In the mode where surplus power is not fed into the grid, the energy management control unit monitors the net power of the grid in real time. When it detects that the photovoltaic power generation exceeds the user's load consumption, it adjusts the output power of the inverter to keep the net power of the grid in the grid at zero or a positive value.

[0006] The beneficial effects of the above technical solution are as follows: This embodiment achieves optimal energy matching between photovoltaic power generation, energy storage, the power grid, and user load through dynamic coordination of the energy management control unit. It prioritizes meeting the user's own electricity needs and rationally allocates surplus electricity to energy storage or the power grid, maximizing the utilization rate of photovoltaic energy and reducing energy waste. The combination of the anti-reverse current monitoring unit and the energy management control unit effectively avoids unreasonable reverse current in the photovoltaic surplus power grid connection mode and power backflow problems in the surplus power off-grid mode, reducing the impact on the power grid and ensuring the safe and stable operation of the power grid.

[0007] In this embodiment, under the surplus power grid connection mode, the energy management and control unit allocates power in an orderly manner according to the gap supply logic of photovoltaic priority self-consumption → energy storage discharge supplementation → grid reserve and the surplus consumption logic of energy storage priority charging → grid surplus power grid connection. This ensures that the self-consumption rate of photovoltaic power is maximized, reducing dependence on the grid. At the same time, it rationally arranges the charging and discharging of energy storage to achieve optimal global energy utilization and improve system operating efficiency and economic benefits.

[0008] In one optional implementation, the backflow prevention monitoring unit includes: Current transformers are installed on each phase line of the power grid incoming line to collect current signals and determine the current direction according to a preset transformation ratio. A bidirectional multi-function meter, connected to the current transformer, is used to collect three-phase voltage, current, active power, reactive power, power factor and power direction data, and calculate and output the net power of the incoming power grid. Wherein, when the net power of the incoming power grid is positive, it indicates that the power grid is supplying power in the forward direction; when the net power of the incoming power grid is negative, it indicates that the power is flowing back to the power grid.

[0009] In one optional implementation, under the surplus power grid connection mode, the energy management control unit also executes the following flexible control logic: the anti-reverse current monitoring unit monitors the power flow direction at the grid connection point in real time and flexibly controls the inverter output power and the energy storage unit charging power to avoid instantaneous power backflow impacting the grid, effectively suppressing grid voltage fluctuations, frequency deviations and other anomalies caused by instantaneous power backflow, and ensuring the stability and safety of grid operation; at the same time, by dynamically coordinating the inverter output power and the energy storage unit charging power, surplus photovoltaic power can be fully utilized to charge the energy storage unit, thereby improving the overall energy utilization efficiency.

[0010] In one optional implementation, the energy management control unit also executes a sudden change in solar power response logic: when the photovoltaic output suddenly increases, the excess power is quickly stored in the energy storage unit; when the photovoltaic output suddenly decreases, the energy storage unit immediately discharges to make up for the power gap; the rapid charging and discharging response of the energy storage unit smooths out grid-connected power fluctuations, thereby improving the stability of user-side power consumption and photovoltaic absorption rate.

[0011] In one optional implementation, in the residual power not connected to the grid mode, the energy management control unit executes the following anti-reverse flow control logic: When the net power of the incoming power grid is greater than or equal to zero, the inverter maintains maximum power operation; When the net power of the grid incoming line is less than zero but greater than the preset reverse current threshold, the inverter output power is gradually reduced. When the net power of the incoming power grid is less than or equal to the preset reverse current threshold, an emergency power reduction or shutdown operation is performed.

[0012] In one optional embodiment, the photovoltaic power supply system further includes a grid-connected / off-grid switching unit, which includes an automatic transfer switch. The control terminal of the automatic transfer switch is connected to the inverter or the energy management control unit. The inverter also has a backup power port. The automatic transfer switch includes a switch body, a normally closed position, a first normally open position, and a second normally open position. One end of the switch body is connected to the normally closed position, and the other end of the switch body is connected to either the first or second normally open position. The normally closed position is connected to the outgoing terminal of the user's inlet distribution box via a first circuit breaker. The first normally open position is connected to the incoming busbar on the grid side. The second normally open position is connected to the backup power port of the inverter via a second circuit breaker. The switch body is connected to the normally closed position and the first normally open position in grid-connected mode, and the switch body is connected to the normally closed position and the second normally open position in off-grid power supply mode. When the anti-reverse current monitoring unit detects a grid fault, the automatic transfer switch of the off-grid switching unit automatically switches to off-grid power supply mode, where the photovoltaic power generation unit and energy storage unit work together to continuously supply power to the user load; when the anti-reverse current monitoring unit detects that the grid has recovered, the automatic transfer switch automatically switches to grid-connected mode, returning to grid-connected operation.

[0013] The beneficial effects of the above technical solution are as follows: The grid-connected / off-grid switching unit effectively ensures continuous power supply to user loads during grid failures, avoiding production and daily life interruptions caused by grid outages, and significantly improving power supply reliability and stability; the combined power supply of photovoltaic power generation units and energy storage units maximizes the utilization of renewable energy, reduces dependence on the traditional power grid, and lowers user electricity costs and carbon emissions; the automatic switching mechanism between grid-connected and off-grid modes requires no manual intervention, simplifying operation and maintenance processes and improving system intelligence; simultaneously, it flexibly adapts to both surplus power grid connection and off-grid power supply scenarios, balancing user economic benefits and emergency power supply needs, enhancing the system's practicality and adaptability. Furthermore, this design can quickly return to grid-connected status after grid restoration, ensuring seamless energy supply continuity, further optimizing energy distribution efficiency, and providing buildings with a safe, efficient, and green integrated power supply solution.

[0014] Secondly, the present invention provides a photovoltaic power supply method, which utilizes the aforementioned photovoltaic power supply system to supply power, comprising the following steps: S1. The backflow prevention monitoring unit collects the electrical parameters of the incoming power grid line in real time and calculates the net power of the incoming power grid line; S2. Receive the photovoltaic output reported in real time by the inverter and the energy storage unit status information reported by the battery management system, and combine them with the net power of the grid incoming line to calculate the user load power by the energy management control unit; S3. Based on the current operating mode of the system, dynamically coordinate the energy flow between the photovoltaic power generation unit, the energy storage unit, and the power grid. The specific steps are as follows: Photovoltaic power generation is prioritized for use by local users. Determine the relationship between user load and photovoltaic output: When the user load exceeds the photovoltaic output, the power gap is supplemented by the discharge of the energy storage unit. When the state of charge of the energy storage unit does not meet the discharge conditions, the grid supplies power. When the user load is less than the photovoltaic output, the surplus electricity is used to charge the energy storage unit first. After the energy storage unit is fully charged or reaches the charging limit, the remaining electricity is fed into the grid. Meanwhile, the anti-backflow monitoring unit monitors the power flow direction at the grid connection point in real time, flexibly adjusting the photovoltaic output and energy storage charging power to avoid instantaneous power backflow impacting the power grid.

[0015] The aforementioned photovoltaic power supply method achieves efficient utilization of photovoltaic power generation and stable interaction with the power grid through precise energy flow coordination and anti-reverse current monitoring. On the one hand, it prioritizes the absorption of photovoltaic energy by local loads, with surplus electricity stored or fed into the grid in an orderly manner, significantly improving the utilization rate of clean energy and reducing users' dependence on traditional power grid electricity. On the other hand, it monitors the power flow direction at the grid connection point in real time and flexibly adjusts power output, effectively avoiding the impact of instantaneous power backflow on the power grid and ensuring the stability and security of power grid operation. At the same time, the dynamic charging and discharging strategy of the energy storage unit smooths out the intermittent fluctuations in photovoltaic output and supplements the power supply gap during peak load periods, improving the reliability of the system power supply. In addition, the bidirectional switching function of surplus electricity fed into the grid and not fed into the grid allows users to flexibly choose the operating mode according to the power system operation specifications and their own needs, taking into account both economy and ease of use.

[0016] In an optional implementation, when the system is operating in surplus power grid connection mode, step S3 includes a sudden change in light intensity response step: When a sudden increase in photovoltaic output leads to an instantaneous power surplus, the excess electricity will be quickly stored in the energy storage unit; When a sudden drop in photovoltaic output leads to a power gap, the energy storage unit immediately discharges to make up for it. Smoothing grid-connected power fluctuations through the rapid charging and discharging throughput of energy storage units: And / or, when the system is operating in a mode where residual power is not connected to the grid, step S3 includes: Real-time monitoring of net power input to the power grid; When the net power is greater than or equal to zero, the inverter operates at maximum power; When the net power is negative and greater than the preset reverse current threshold, the inverter output power is gradually reduced so that the net power approaches zero. When the net power is less than or equal to the preset reverse current threshold, an emergency power reduction or shutdown operation is performed to prevent photovoltaic power from being transmitted back to the grid.

[0017] In an optional implementation, an all-weather energy optimization scheduling step is also included: During the daytime photovoltaic power generation period, the strategy of prioritizing self-consumption, storing surplus energy, and feeding surplus power into the grid is implemented. During nighttime periods without solar power, the energy storage unit discharges to supply user loads according to peak-valley electricity pricing strategies, replacing the high-priced power grid.

[0018] In summary, the aforementioned photovoltaic power supply system and methods support three operating modes: self-consumption with surplus power fed into the grid, surplus power not fed into the grid, and full grid connection. They are suitable for residential buildings, shops, and small and medium-sized industrial and commercial establishments without emergency power supply needs. They feature low investment, simple operation and maintenance, and high energy efficiency. Users can choose to save money for self-consumption, generate revenue from surplus power, or sell all electricity to the grid, adapting to various electricity consumption and profit requirements. They are economical, practical, and widely adaptable.

[0019] Self-consumption with surplus power fed into the grid, and surplus power not fed into the grid: The photovoltaic line is connected to the user's distribution box on the power consumption side. In the surplus power not fed into the grid mode, an anti-backflow monitoring device is installed to monitor the grid incoming current in real time, intelligently adjust the inverter output power, and prevent photovoltaic power generation from being fed back into the grid.

[0020] Thirdly, the present invention provides a building energy storage power supply system, comprising: Building roof; The photovoltaic power supply system is installed on the roof of the building; The photovoltaic power generation unit in the photovoltaic power supply system includes a support system, photovoltaic modules, a drainage system, and a cleaning device; The support system is fixed to the roof of the building and forms an overhead support structure above the roof surface, and the top surface of the support system forms a photovoltaic mounting surface; The photovoltaic modules are laid on the photovoltaic mounting surface to convert solar energy into electrical energy. The drainage system is installed between the support system and the photovoltaic module; The cleaning device is connected to the drainage system and is used to flush away sludge deposited in the drainage system. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a system diagram of the pure photovoltaic system with full grid connection mode of the present invention; Figure 2 This is a system diagram of the pure photovoltaic system of the present invention - self-consumption and surplus power grid connection mode; Figure 3 This is a system diagram of the pure photovoltaic system of the present invention - self-consumption with surplus power not fed into the grid; Figure 4 This is a diagram of the power storage system without backup power according to the present invention; Figure 5 This is a diagram of the power distribution and backup system - whole-house backup power system of the present invention; Figure 6 A schematic diagram of the support system structure of the building energy storage power supply system provided by the present invention; Figure 7 Another structural schematic diagram of the support system for the building energy storage power supply system provided by the present invention; Figure 8This is a structural schematic diagram of the building energy storage power supply system provided by the present invention; Figure 9 Another structural schematic diagram of the building energy storage power supply system provided by the present invention; Figure 10 A schematic diagram of the first drainage system of the building energy storage power supply system provided by the present invention; Figure 11 A schematic diagram of the second type of drainage system for the building energy storage power supply system provided by the present invention; Figure 12 A schematic diagram of the connection structure between the building energy storage power supply system and the photovoltaic module provided by the present invention.

[0023] Explanation of reference numerals in the attached figures: 100. Photovoltaic power generation unit; 101. Support system; 1011. Column; 1012. Main beam; 1013. Purlin; 1014. Decorative component; 102. Photovoltaic module; 1021. Photovoltaic panel; 1022. Module frame; 103. Drainage system; 1031. Longitudinal M-shaped water guide channel; 1032. Horizontal sub-water guide channel; 1033. Horizontal main water guide channel; 1034. Longitudinal small water channel; 1035. Horizontal intermediate water channel; 1036. Longitudinal intermediate water channel. 1037. Horizontal main water tank; 104. Connecting structure; 1041. Back pressure block; 10411. Connecting part; 10412. Abutting part; 10413. First protrusion; 10414. Second protrusion; 1042. Bracket; 10421. First positioning part; 10422. Second positioning part; 10423. First positioning groove; 10424. Second positioning groove; 1043. Adapter; 1044. First locking assembly; 1045. Second locking assembly. 200. Energy storage unit; 300. Inverter; 400. Backflow prevention monitoring device; 500. Automatic transfer switch; 600. Power grid incoming line box; 700. Household electricity meter; 800. User's in-home distribution box; 900. AC distribution box; 901. Incoming circuit breaker; 902. Surge protector; 903. Outgoing circuit breaker; 904. Disconnecting switch; 1000, Photovoltaic metering box; 1001, Photovoltaic metering electricity meter. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] According to an embodiment of the present invention, in a first aspect, a photovoltaic power supply system is provided, comprising: a photovoltaic power generation unit 100, an energy storage unit 200, a battery management system, an inverter 300, a user load power monitoring unit, and an anti-reverse current monitoring device 400.

[0026] The photovoltaic power generation unit 100 has a DC output terminal for generating electricity using solar energy.

[0027] The energy storage unit 200 has a charging and discharging terminal.

[0028] The inverter 300 has a photovoltaic DC input terminal and an energy storage DC input terminal on its DC side. The photovoltaic DC input terminal is electrically connected to the DC output terminal of the photovoltaic power generation unit 100, and the energy storage DC input terminal is electrically connected to the charging and discharging terminal of the energy storage unit 200. The inverter 300 is connected in parallel to the power grid and user loads on its AC side.

[0029] The user load power monitoring unit is installed at the user load location to monitor the user load power.

[0030] The anti-reverse current monitoring device 400 includes an anti-reverse current monitoring unit and an energy management control unit. The current sampling terminal of the anti-reverse current monitoring unit is installed at the power grid inlet, and the signal output terminal of the anti-reverse current monitoring unit is connected to the energy management control unit. The anti-reverse current monitoring unit is used to collect current information from the power grid inlet. The energy management control unit is communicatively connected to the anti-reverse current monitoring unit, the inverter 300, the energy storage unit 200, and the user load power monitoring unit.

[0031] The operation modes of photovoltaic power supply systems include surplus power grid connection mode and surplus power not grid connection mode.

[0032] In the surplus power grid connection mode, the energy management control unit receives the net power of the grid incoming line reported by the anti-reverse current monitoring unit, the photovoltaic output reported by the inverter 300, the status of the energy storage unit 200 reported by the battery management system, and the user load power reported by the user load power monitoring unit. It dynamically coordinates the energy matching between the photovoltaic power generation unit, the energy storage unit, the grid, and the user load, and automatically allocates power according to preset priorities to achieve optimal energy utilization. The energy management control unit executes the following energy allocation logic: Both photovoltaic and energy storage are connected in parallel to the user's load electricity consumption side, with photovoltaic power generation prioritizing supply to local loads. The system no longer rigidly restricts reverse flow, but instead intelligently identifies load surplus and deficit through anti-reverse flow monitoring devices, automatically allocating three destinations: "self-use, energy storage charging, and surplus power to the grid," maximizing local consumption and rationally utilizing surplus power to the grid for revenue.

[0033] When the user load exceeds the photovoltaic output, i.e., a power shortage condition, the anti-reverse current monitoring device detects in real time that the local load consumption exceeds the photovoltaic power generation, and the photovoltaic power is used entirely locally. The power shortage is preferentially supplemented by the discharge of energy storage units, reducing the amount of electricity drawn from the grid; if the state of charge (SOC) of the energy storage is too low and does not meet the discharge conditions, it automatically switches to grid-based backup power. Through peak discharge of energy storage, the peak electricity consumption of users is effectively reduced, achieving peak shaving and energy saving.

[0034] When the user load is less than the photovoltaic output, i.e., the power generation surplus condition, surplus electricity is generated, and the system executes a tiered optimal consumption strategy: First priority: Excess electricity is used to charge the energy storage unit first, storing the excess electricity of the photovoltaic power generation unit 100; Second priority: After the energy storage unit is fully charged or reaches its charging limit, the remaining power will be fed into the grid in a controllable and orderly manner.

[0035] The anti-backflow monitoring device monitors the power flow direction at the grid connection point in real time, flexibly adjusting the photovoltaic output and energy storage charging power to avoid instantaneous power backflow impacting the grid and ensure stable and compliant grid connection of surplus power. This allocation logic ensures the priority of self-consumption of photovoltaic power, reasonable charging and discharging scheduling of energy storage units, and the tiered utilization strategy of grid power as a last resort, achieving an orderly and efficient allocation of global energy.

[0036] In the surplus power not fed into the grid mode, the energy management control unit monitors the net power of the grid input line in real time. When it detects that the photovoltaic power generation exceeds the user's load consumption, it adjusts the output power of the inverter 300 to maintain the net power of the grid input line at zero or a positive value, thereby preventing photovoltaic power from being transmitted back to the grid. During the adjustment process, the energy management control unit can also link with the energy storage unit 200 to increase the charging power to absorb the excess DC power, achieving reverse current prevention while ensuring reasonable charging of the energy storage unit and avoiding energy waste.

[0037] This embodiment achieves optimal energy matching between photovoltaic power generation, energy storage, the power grid, and user load through dynamic coordination of the energy management control unit. It prioritizes meeting users' own electricity needs and rationally allocates surplus electricity to energy storage or the power grid, maximizing the utilization rate of photovoltaic energy and reducing energy waste. The combination of the anti-reverse current monitoring unit and the energy management control unit effectively avoids unreasonable reverse current in the photovoltaic surplus power grid connection mode and power backflow problems in the surplus power off-grid mode, reducing the impact on the power grid and ensuring its safe and stable operation.

[0038] In this embodiment, under the surplus power grid connection mode, the energy management and control unit allocates power in an orderly manner according to the gap supply logic of photovoltaic priority self-consumption → energy storage discharge supplementation → grid reserve and the surplus consumption logic of energy storage priority charging → grid surplus power grid connection. This ensures that the self-consumption rate of photovoltaic power is maximized, reducing dependence on the grid. At the same time, it rationally arranges the charging and discharging of energy storage to achieve optimal global energy utilization and improve system operating efficiency and economic benefits.

[0039] In some embodiments, the backflow prevention monitoring unit includes a current transformer and a bidirectional multifunction meter.

[0040] Current transformers are installed on the A / B / C phase lines of the incoming power grid to collect current signals according to a preset transformation ratio and determine the current direction. Specifically, the current transformers convert large currents into smaller signals proportionally (e.g., 500 / 5A) for sampling by the anti-reverse current meter. When the current transformer detects a forward current, it indicates that the power grid is supplying power to the user load; when the current transformer detects a reverse current, it indicates that the photovoltaic power generation unit 100 is supplying power to the power grid.

[0041] The bidirectional multi-function meter is a backflow prevention meter. It connects to a current transformer, specifically via an RS485 line. The bidirectional multi-function meter is used to collect real-time data on three-phase voltage, current, active power, reactive power, power factor, and power direction, and calculates the net power input to the power grid. A positive net power input indicates positive grid supply, while a negative net power input indicates that the electricity generated by the photovoltaic power generation unit 100 is flowing back to the grid.

[0042] The energy management control unit receives current, power, and direction signals from the current transformer (CT) and bidirectional multifunction meter, calculates the reverse current power value, and generates a power reduction command according to a preset strategy (such as "reverse current > 5% of rated power"). When the net power of the grid incoming line is greater than or equal to zero, no intervention is made to inverter 300, and inverter 300 maintains maximum power operation; When the net power of the grid incoming line is less than zero but greater than the preset reverse current threshold, the inverter 300 is flexibly adjusted to gradually reduce the output power of the inverter 300. When the net power of the grid incoming line is less than or equal to the preset reverse current threshold, an instruction is sent to the inverter via RS485 / Modbus / TCP to perform an emergency power reduction or shutdown operation.

[0043] The inverter, acting as the execution unit, receives instructions from the energy management control unit: 0–100% active power limit; fast response (seconds): reduce output current → reduce power generation until the reverse current disappears.

[0044] This embodiment achieves precise anti-reverse current control. By real-time acquisition and direction determination of the current in each phase of the grid incoming line through current transformers, combined with multi-parameter monitoring by a bidirectional multi-function meter, it can accurately identify the grid supply and photovoltaic reverse current status, effectively preventing photovoltaic power generation units from flowing back into the grid, ensuring grid operation safety, and meeting grid connection technical requirements. This embodiment optimizes system operating efficiency. The energy management control unit executes differentiated control strategies based on the net power status of the grid incoming line. During non-reverse current conditions, it maintains the inverter at maximum power to maximize power generation revenue; when approaching the reverse current threshold, it flexibly adjusts the power, avoiding energy waste and ensuring system stability. This embodiment improves response speed and reliability. The inverter can respond to power reduction commands within seconds, eliminating reverse current by rapidly adjusting the output current, reducing the risk of system downtime. Simultaneously, the comprehensive electrical parameter data provided by the bidirectional multi-function meter provides data support for system operation and maintenance, fault diagnosis, and strategy optimization, enhancing the overall reliability and maintainability of the system.

[0045] In some embodiments, under the surplus power grid connection mode, the energy management control unit also executes the following flexible control logic: the anti-backflow monitoring unit monitors the power flow direction at the grid connection point in real time and flexibly controls the output power of the inverter 300 and the charging power of the energy storage unit to avoid instantaneous power backflow impacting the grid, effectively suppressing grid voltage fluctuations, frequency deviations and other anomalies caused by instantaneous power backflow, and ensuring the stability and safety of grid operation; at the same time, by dynamically coordinating the output power of the inverter and the charging power of the energy storage unit, the surplus photovoltaic power can be fully utilized to charge the energy storage unit, improving the overall energy utilization efficiency; in addition, this flexible control method avoids the loss of power generation revenue caused by traditional rigid shutdown, takes into account the economy and reliability of system operation, and meets the grid connection technical specifications and safety requirements of building energy storage power supply systems under the surplus power grid connection mode.

[0046] In some embodiments, to address the issue of sudden increases and decreases in photovoltaic power caused by fluctuations in sunlight, the system utilizes the rapid throughput characteristics of energy storage for real-time fine-tuning. The energy management control unit also executes a sudden change in sunlight response logic: when photovoltaic output suddenly increases, excess electricity is quickly stored in the energy storage unit; when photovoltaic output suddenly decreases, the energy storage unit immediately discharges to make up for the power gap; through the rapid charging and discharging response of the energy storage unit, grid-connected power fluctuations are smoothed out, improving the stability of user-side power consumption and photovoltaic absorption rate.

[0047] Grid and energy storage collaborative energy-saving optimization (optimal strategy throughout the day): The system dynamically matches energy flow direction based on real-time load data. During peak solar power generation periods in the daytime: prioritize self-consumption, store surplus electricity, and feed surplus power into the grid to maximize the benefits of solar power; During nighttime periods without solar power: In accordance with the electricity pricing strategy, energy storage discharges to supply the load, replacing high-priced grid electricity and reducing users' electricity costs; The entire process is linked with the anti-backflow and energy management control unit to intelligently balance the relationship between self-generation and self-consumption, energy storage and release, and surplus electricity grid connection, thus eliminating the waste of ineffective power.

[0048] By combining the power consumption-side access architecture with anti-reverse current intelligent monitoring and control, the energy allocation of local photovoltaic consumption, energy storage charging and discharging, and surplus electricity grid connection is dynamically optimized without the need for energy storage and under the premise of full grid connection. This maximizes photovoltaic utilization, minimizes grid purchases, and optimizes energy utilization within the station, achieving efficient and flexible operation of photovoltaic-storage-grid-load synergy.

[0049] In some embodiments, the photovoltaic power supply system further includes a grid-connected / off-grid switching unit, which includes an automatic transfer switch 500. The control terminal of the automatic transfer switch 500 is connected to the inverter 300 or an energy management control unit. The inverter 300 also has a backup power port. The automatic transfer switch 500 includes a switch body, a normally closed position, a first normally open position, and a second normally open position. One end of the switch body is connected to the normally closed position, and the other end of the switch body is connected to either the first or second normally open position. The normally closed position is connected to the outgoing terminal of the user's inlet distribution box 800 via a first circuit breaker. The first normally open position is connected to the grid-side incoming busbar. The second normally open position is connected to the backup power port of the inverter 300 via a second circuit breaker. The switch body is connected to the normally closed position and the first normally open position in grid-connected mode, and the switch body is connected to the normally closed position and the second normally open position in off-grid power supply mode.

[0050] When the anti-reverse current monitoring device 400 detects a grid fault, the automatic transfer switch 500 of the off-grid switching unit automatically switches to off-grid power supply mode, and the photovoltaic power generation unit 100 and the energy storage unit 200 jointly provide continuous power supply to the user load; when the anti-reverse current monitoring device 400 detects that the grid has been restored, the automatic transfer switch 500 automatically switches to grid-connected mode and returns to grid-connected operation.

[0051] The method of the anti-reverse current monitoring device 400 for detecting power grid faults is as follows: real-time acquisition of voltage, frequency, and phase signals of the incoming busbar on the power grid side; comparison of the acquired voltage value with the preset normal voltage range of the power grid, frequency value with the preset normal frequency range of the power grid, and phase value with the preset normal phase range of the power grid; if any one of the voltage, frequency, or phase continuously exceeds the corresponding normal range and the duration reaches a preset threshold, a power grid fault is determined; at the same time, the anti-reverse current monitoring device also monitors the current direction on the power grid side. If a reverse current trend is detected at the same time as the abnormal power grid parameters, the power grid fault status will be further verified and confirmed.

[0052] The method used by the anti-reverse current monitoring device 400 to detect grid recovery is as follows: Real-time acquisition of voltage, frequency, and phase signals from the incoming busbar on the grid side; comparison of the acquired voltage value with the preset normal grid voltage range, frequency value with the preset normal grid frequency range, and phase value with the preset normal grid phase range; if the voltage, frequency, and phase are all continuously within their corresponding normal ranges and the duration reaches the preset recovery confirmation threshold, it is preliminarily determined that the grid has shown signs of recovery; simultaneously, the anti-reverse current monitoring device also monitors the current direction on the grid side. If the current direction maintains the normal flow direction during grid-connected operation and there is no reverse flow trend, it is finally confirmed that the grid has returned to normal.

[0053] This embodiment effectively ensures continuous power supply to user loads during grid failures through a grid-connected / off-grid switching unit, avoiding production and daily life interruptions caused by grid outages and significantly improving power supply reliability and stability. By combining photovoltaic power generation and energy storage units, it maximizes the utilization of renewable energy, reduces dependence on the traditional grid, and lowers user electricity costs and carbon emissions. The automatic switching mechanism between grid-connected and off-grid modes requires no manual intervention, simplifying operation and maintenance processes and improving system intelligence. Simultaneously, it flexibly adapts to both surplus power grid connection and off-grid power supply scenarios, balancing user economic benefits with emergency power needs, enhancing the system's practicality and adaptability. Furthermore, this design allows for rapid return to grid-connected status after grid restoration, ensuring seamless energy supply continuity, further optimizing energy distribution efficiency, and providing buildings with a safe, efficient, and green integrated power supply solution.

[0054] In some embodiments, the photovoltaic power supply system further includes a grid incoming box 600, which contains a household electricity meter 700. The household electricity meter 700 is located at the grid incoming line and is used to measure the electrical energy entering the grid. The output terminal of the household electricity meter 700 is connected to the input terminal of the inverter 300.

[0055] In some embodiments, the AC side of the inverter is connected to the power grid via an AC distribution box 900. The AC distribution box contains an incoming circuit breaker 901, a surge protector 902, an outgoing circuit breaker 903, and a disconnector 904 connected in series along the direction from the incoming line to the outgoing line. The AC side of the inverter is connected to the outgoing end of the outgoing circuit breaker via the incoming circuit breaker. The surge protector is installed on the line between the incoming circuit breaker and the outgoing circuit breaker.

[0056] A photovoltaic metering box 1000 is connected in series between the AC side of the inverter and the power grid. A photovoltaic meter 1001 is installed inside the photovoltaic metering box. The photovoltaic metering box is connected in series between the AC side of the inverter and the outgoing terminal of the AC distribution box.

[0057] According to an embodiment of the present invention, in a second aspect, a photovoltaic power supply method is provided, comprising the following steps: S1. The electrical parameters of the incoming power grid are collected in real time through the anti-backflow monitoring unit, and the net power of the incoming power grid is calculated.

[0058] S2. Receive the photovoltaic output reported in real time by the inverter 300 and the status information of the energy storage unit 200 reported by the battery management system, and combine them with the net power of the grid incoming line to calculate the user load power by the energy management control unit.

[0059] S3. Based on the current operating mode of the system, dynamically coordinate the energy flow between the photovoltaic power generation unit, the energy storage unit and the power grid.

[0060] When the system is operating in surplus power grid connection mode, step S3 includes an energy allocation step: Photovoltaic power generation is prioritized for use by local users. Determine the relationship between user load and photovoltaic output: When the user load exceeds the photovoltaic output, the power gap is supplemented by the discharge of the energy storage unit. When the state of charge of the energy storage unit does not meet the discharge conditions, the grid supplies power. When the user load is less than the photovoltaic output, the surplus electricity is used to charge the energy storage unit first. After the energy storage unit is fully charged or reaches the charging limit, the remaining electricity is fed into the grid. Meanwhile, the anti-backflow monitoring unit monitors the power flow direction at the grid connection point in real time, flexibly adjusting the photovoltaic output and energy storage charging power to avoid instantaneous power backflow impacting the power grid.

[0061] The aforementioned photovoltaic power supply method achieves efficient utilization of photovoltaic power generation and stable interaction with the power grid through precise energy flow coordination and anti-reverse current monitoring. On the one hand, it prioritizes the absorption of photovoltaic energy by local loads, with surplus electricity stored or fed into the grid in an orderly manner, significantly improving the utilization rate of clean energy and reducing users' dependence on traditional power grid electricity. On the other hand, it monitors the power flow direction at the grid connection point in real time and flexibly adjusts power output, effectively avoiding the impact of instantaneous power backflow on the power grid and ensuring the stability and security of power grid operation. At the same time, the dynamic charging and discharging strategy of the energy storage unit smooths out the intermittent fluctuations in photovoltaic output and supplements the power supply gap during peak load periods, improving the reliability of the system power supply. In addition, the bidirectional switching function of surplus electricity fed into the grid and not fed into the grid allows users to flexibly choose the operating mode according to the power system operation specifications and their own needs, taking into account both economy and ease of use.

[0062] In some embodiments, when the system is operating in surplus power grid connection mode, step S3 includes a sudden change in solar power response step: when a sudden increase in photovoltaic output leads to instantaneous power surplus, the excess power is quickly stored in the energy storage unit; when a sudden drop in photovoltaic output leads to power deficit, the energy storage unit discharges immediately to make up for it; and the rapid charging and discharging throughput of the energy storage unit smooths out grid-connected power fluctuations.

[0063] Specifically, the anti-reverse current monitoring unit collects power data from the grid connection point in real time. When a sudden increase in photovoltaic output is detected, causing the instantaneous power to exceed local load consumption and posing a risk of backfeeding to the grid, the system immediately sends a fast charging command to the energy storage inverter. The energy storage inverter switches to charging mode to absorb excess power at the maximum allowable charging power. Simultaneously, the photovoltaic inverter dynamically adjusts its output power according to the charging status of the energy storage unit to ensure that the power at the grid connection point is always maintained within the non-backfeed range. When a sudden drop in photovoltaic output is detected, causing a power gap, the anti-reverse current monitoring unit triggers the discharge response of the energy storage inverter. The energy storage inverter outputs compensation power at a preset response speed to quickly fill the difference between load demand and photovoltaic output, ensuring the continuity of local power supply.

[0064] This sudden change in sunlight response mechanism effectively addresses power fluctuations caused by sudden events such as cloud cover and abrupt changes in sunlight intensity during photovoltaic power generation, ensuring that the grid-connected power remains within a stable range and preventing grid impacts from instantaneous power anomalies. Simultaneously, the rapid charge and discharge response of the energy storage unit maximizes the retention of surplus photovoltaic power, reducing energy waste and further enhancing the system's ability to absorb clean energy. This ensures that users can enjoy benefits in the surplus power grid connection mode while maintaining stable interaction between the system and the grid, balancing the economic efficiency of system operation with the security of grid interaction.

[0065] In some embodiments, when the system operates in a mode where surplus power is not fed into the grid, step S3 includes: real-time monitoring of the net power of the grid input line; when the net power is greater than or equal to zero, the inverter 300 operates at maximum power; when the net power is negative and greater than a preset reverse current threshold, the output power of the inverter 300 is gradually reduced so that the net power approaches zero; when the net power is less than or equal to the preset reverse current threshold, an emergency power reduction or shutdown operation is performed to prevent photovoltaic power from being transmitted back to the grid.

[0066] This embodiment employs a tiered response and refined management strategy. It maximizes the power generation capacity of the photovoltaic inverter when net power is within a safe range, fully meeting the local load's electricity demand. Simultaneously, it rapidly initiates power regulation or shutdown measures when net power approaches or reaches the reverse current threshold, fundamentally eliminating the risk of photovoltaic power being fed back into the grid and ensuring grid stability. Furthermore, this dynamic adjustment method avoids the waste of clean energy due to excessive power reduction, achieving efficient utilization of local energy in a surplus-without-grid mode, thus balancing the continuity of user-side electricity consumption with the security of grid interaction.

[0067] In some embodiments, the photovoltaic power supply method further includes an all-weather energy optimization scheduling step: during the daytime photovoltaic power generation period, a strategy of prioritizing self-consumption, storing surplus energy, and feeding surplus power into the grid is implemented; during the nighttime periods without photovoltaic power generation, the energy storage unit is controlled to discharge and supply user loads according to the peak-valley electricity price strategy, replacing the high-priced grid. This all-weather energy optimization scheduling step, through a time-sharing differentiated strategy, fully utilizes photovoltaic output to meet local load demand during the daytime, stores surplus electricity in energy storage units to avoid waste of clean energy, and feeds surplus power into the grid when necessary to supplement grid power; at night, it utilizes the peak-valley electricity price difference to release the stored electricity in the energy storage unit to supply power to users, effectively reducing users' electricity costs during peak electricity price periods. This scheduling method not only significantly improves the comprehensive utilization efficiency of photovoltaic energy, but also assists the grid in peak shaving and valley filling, achieving dual optimization of user-side economic benefits and grid-side operational stability, further enhancing the system's energy configuration flexibility at different times.

[0068] In summary, the aforementioned photovoltaic power supply system and methods support three operating modes: self-consumption with surplus power fed into the grid, surplus power not fed into the grid, and full grid connection. They are suitable for residential buildings, shops, and small and medium-sized industrial and commercial establishments without emergency power supply needs. They feature low investment, simple operation and maintenance, and high energy efficiency. Users can choose to save money for self-consumption, generate revenue from surplus power, or sell all electricity to the grid, adapting to various electricity consumption and profit requirements. They are economical, practical, and widely adaptable.

[0069] Self-consumption with surplus power fed into the grid, and surplus power not fed into the grid: The photovoltaic line is connected to the user's distribution box on the power consumption side. In the surplus power not fed into the grid mode, an anti-backflow monitoring device is installed to monitor the grid incoming current in real time, intelligently adjust the inverter output power, and prevent photovoltaic power generation from being fed back into the grid.

[0070] The power supply mode of photovoltaic power supply systems has evolved from the traditional full grid connection mode to include three major systems: pure photovoltaic, distribution-storage without backup power, and distribution-storage. These three systems represent a progressive technological advancement with layered functions. Pure photovoltaic: the basic version, only capable of power generation, grid connection, and self-consumption / grid connection; its functions are the simplest. Distribution-storage without backup power: adds energy storage units to the pure photovoltaic system, optimizing energy consumption and grid adaptability, without adding backup power functionality. Distribution-storage with backup power: adds grid-connected / off-grid switching and emergency power supply logic to the complete distribution-storage without backup power configuration. All support a two-way operation mode of self-consumption with surplus power connected to the grid / not connected to the grid, constructing a new power supply system that is photovoltaic-storage synergistic, two-way flexible, and multi-adaptable, flexibly matching user scenarios and grid demands. "Two-way" refers to the bidirectional flow of energy. "Flexible" refers to the adjustable power output: the inverter output power is flexibly adjustable, achieved through the charging and discharging of the energy storage battery or the inverter's own EMS system, and the operation mode can be smoothly switched, no longer the rigid mode of traditional full grid connection and only unidirectional power supply.

[0071] Reference Figure 1 , Figure 1 This is a system diagram for a pure photovoltaic system in a grid-connected mode. In this mode, the photovoltaic output is directly connected to the national power grid for unified power transmission.

[0072] Reference Figure 2 , Figure 2 This is a system diagram for a pure photovoltaic system in a self-consumption and surplus power grid connection mode, where the photovoltaic lines are connected to the user's distribution box on the power consumption side.

[0073] Reference Figure 3 , Figure 3 This is a system diagram for a pure photovoltaic system – a self-consumption model where surplus electricity is not fed into the grid. Figure 2 On the basis of this, an anti-backflow monitoring device is added to monitor the grid incoming current in real time, intelligently adjust the inverter output power, and prevent photovoltaic power generation from being transmitted back to the grid.

[0074] Reference Figure 4 , Figure 4This diagram illustrates a power storage system without backup power. Such systems are suitable for homes, shops, and small and medium-sized enterprises where daily energy saving and cost reduction are desired, and where emergency power supply is not required during power outages. They support both self-consumption with surplus power fed into the grid and off-grid operation. Energy storage can be used to profit from peak-valley electricity price differences and store surplus photovoltaic power for daily use, effectively reducing grid power consumption and lowering electricity costs. Furthermore, they can be integrated with anti-reverse current monitoring devices to prevent power from being transmitted back to the grid. The equipment investment is moderate, and operation and maintenance are simple, balancing energy-saving benefits and grid compatibility. The photovoltaic lines of the power storage system are connected to the user's distribution box on the power consumption side. All energy storage systems are equipped with anti-reverse current monitoring devices. In the surplus power fed into the grid mode, the anti-reverse current monitoring device monitors the load in real time and intelligently adjusts the power of the photovoltaic system, the grid, and the energy storage battery to achieve optimal energy utilization. In the surplus power off-grid mode, the anti-reverse current monitoring device monitors the grid incoming current in real time and intelligently adjusts the inverter output power to prevent photovoltaic power from being transmitted back to the grid.

[0075] Reference Figure 5 , Figure 5 For the power backup system diagram - whole house backup power system, please refer to... Figure 6 , Figure 6 This diagram illustrates a power storage backup system for critical loads. Residential energy storage backup systems are suitable for residential homes, home offices, households with many appliances, and families requiring guaranteed basic electricity supply during power outages. When combined with photovoltaic (PV) systems, they can operate in multiple modes: self-consumption, grid connection of surplus power, and off-grid operation. This system not only saves electricity and reduces bills during daily use but also automatically switches to off-grid power during grid outages, ensuring stable operation of core loads such as lighting and appliances. It offers high power reliability, balancing daily energy savings with emergency power needs, and is safe and practical for home use.

[0076] All energy storage systems are equipped with anti-reverse current monitoring devices. In the surplus power grid connection mode, the anti-reverse current monitoring device monitors the load in real time and intelligently adjusts the power of photovoltaic, grid, and energy storage batteries to achieve optimal energy utilization. In the surplus power off-grid mode, the anti-reverse current monitoring device monitors the grid incoming current in real time and intelligently adjusts the inverter output power to prevent photovoltaic power generation from being fed back to the grid. The anti-reverse current monitoring device in this system monitors the load in real time and intelligently adjusts the power of photovoltaic, grid, and energy storage batteries. In the surplus power grid connection mode, the anti-reverse current monitoring device prioritizes self-use, energy storage, and orderly grid connection of surplus power, while retaining flexible power control to prevent instantaneous reverse current from impacting the grid. After a grid power outage, it automatically switches to islanded backup power mode, disconnecting the grid connection, and the photovoltaic and energy storage systems work together to continuously supply power to important loads, matching the load size according to capacity. After the grid is restored, it automatically reconnects to the grid and returns to normal energy dispatch. The entire mechanism takes into account the economics of grid-connected operation, grid security, and emergency power supply capabilities in fault conditions.

[0077] In summary, the above-mentioned photovoltaic power supply system and method have the following beneficial effects: Compared to the user side, the aforementioned photovoltaic power supply system and methods address four major pain points: insufficient power supply security, unreasonable investment allocation, limited utilization of surplus power, and difficulty in matching different scenarios. Specifically, these are reflected as follows: Insufficient power supply: 1) Pure photovoltaic system: As a basic power supply unit, it meets the basic electricity needs during the daily sunshine period, replaces part of the mains power, and strengthens the basic power supply capacity.

[0078] 2) Distribution and storage without backup power system: Photovoltaic and energy storage operate in tandem. When photovoltaic output fluctuates or sunlight weakens, the energy storage can quickly discharge to replenish energy, smooth out power gaps, solve the problem of intermittent photovoltaic power generation, and improve the stability of daily power supply.

[0079] 3) Distribution and Storage Power System: Equipped with on-grid and off-grid islanding switching function, combined with anti-reverse current and EMS linkage monitoring of grid status. When the mains power fails and power is lost, the system automatically switches to off-grid backup power mode, with photovoltaic + energy storage jointly providing continuous power to important loads; after the grid is restored, it automatically reconnects to the grid to achieve uninterrupted emergency power supply.

[0080] Unreasonable investment allocation: The aforementioned photovoltaic power supply system adopts a modular, multi-level system architecture, with the three major systems being independently selectable and operating in combination, enabling on-demand configuration, precise cost control, and optimized investment structure. Tiered configuration, select according to needs: 1) Only basic photovoltaic power generation is required, with no peak shaving or emergency needs: Pure photovoltaic systems are selected, which have the simplest equipment and the lowest initial investment, making them suitable for low-cost basic renovation scenarios.

[0081] 2) If peak shaving and valley filling are required, and self-consumption rate is improved, but there is no power outage protection requirement: Select a power distribution and storage system without backup power, increase energy storage to achieve energy efficiency optimization, do not configure off-grid hardware, and reduce unnecessary investment.

[0082] 3) For important loads and emergency backup power: upgrade to a distribution and backup power system, and only deploy and install supporting equipment such as off-grid switching and islanding control in scenarios with essential needs.

[0083] Single method of utilizing surplus electricity: All of the aforementioned photovoltaic power supply systems support free switching between self-consumption with surplus power fed into the grid and non-grid operation with surplus power. Combined with anti-reverse current monitoring devices and EMS intelligent energy dispatching, they enrich the pathways for surplus power consumption. 1) Prioritize local self-use of photovoltaic and energy storage and connect them to the user's electricity consumption side. The generated electricity should be supplied to the local load first, reducing the generation of surplus electricity from the source and increasing the self-consumption ratio.

[0084] 2) When there is a surplus in power generation, the energy storage battery is charged first to store the excess power and release it at night and during peak electricity consumption to achieve peak shifting and reduce curtailment of solar power.

[0085] 3) When the power system operation specifications allow for controllable surplus power grid connection, switch to surplus power grid connection mode. The surplus power after the energy storage is fully charged is orderly transmitted to the power grid to generate grid connection revenue.

[0086] 4) In scenarios where the power grid restricts backfeeding and internal closed-loop power consumption, the system achieves zero backflow and closed-loop self-consumption, switches to a mode where surplus power is not fed into the grid, and uses the anti-backflow monitoring device to dynamically adjust the photovoltaic output, achieving zero power abandonment and zero backflow, and realizing the internal closed-loop utilization of electricity.

[0087] The four consumption paths can be flexibly switched, breaking the limitations of the traditional single surplus power disposal and maximizing power utilization and comprehensive benefits.

[0088] Difficulty in scene matching: By using EMS and anti-backflow monitoring devices to achieve adaptive switching of operating modes, it can be matched with various scenarios such as regular power consumption, emergency power supply, changes in power system operation specifications, and equipment maintenance, making it flexible in operation and highly applicable.

[0089] Compared to the grid side, the aforementioned photovoltaic power supply systems and methods alleviate four major problems: voltage fluctuations, difficulties in power absorption, peak-valley load imbalance, and high investment in grid construction. Specifically, these are reflected in the following: Mitigating grid voltage fluctuations: 1) When short-term fluctuations cause sudden changes in sunlight to cause a sudden increase or decrease in photovoltaic output, the energy storage provides a millisecond-level response: when the output suddenly increases, it immediately charges to absorb the excess power; when the output suddenly decreases, it quickly discharges to make up for the power gap, offsetting photovoltaic power fluctuations and avoiding drastic fluctuations in grid connection voltage.

[0090] 2) The power flexible regulation system supports continuous adjustment of photovoltaic output power. Combined with the anti-reverse current monitoring device, it smoothly manages grid-connected power, eliminates instantaneous high power backflow or power deficit, and reduces voltage surges.

[0091] Solving the problem of power consumption difficulties: Construct a multi-level consumption system of "self-consumption priority + energy storage + controllable grid connection + zero reverse current interlocking" to locally consume photovoltaic power and reduce the pressure on external grid transmission: 1) Maximize the local consumption of photovoltaic power and energy storage, and integrate them with the user's electricity consumption side. The generated electricity is given priority to supply local loads, thereby reducing the amount of electricity sent to other regions from the source.

[0092] 2) Energy storage absorbs surplus power. When the photovoltaic output exceeds the load, the surplus power is preferentially stored in the energy storage battery, converting the instantaneous excess power into power that can be used in time-sharing, and greatly reducing the amount of power fed back to the grid during peak hours.

[0093] 3) Flexible management of grid-connected power: The system supports two-way switching between grid connection and no grid connection when power is remaining. When the power grid has sufficient absorption capacity, surplus electricity will be transmitted to the grid in an orderly manner. When the grid load is low and the pressure to absorb the load is high, the system switches to zero reverse current mode and limits the output of photovoltaic power through anti-reverse current monitoring devices to prevent curtailment and excessive transmission.

[0094] Improving peak-valley load imbalance: By leveraging the core function of energy storage in peak shaving and valley filling, the electricity load is shifted to mitigate the peak-to-valley difference in the power grid. 1) During the daytime peak solar power generation period when the power grid is in a low load period, the surplus solar power is stored in energy storage to reduce the daytime power supply pressure on the power grid and fill the load gap during the daytime peak period.

[0095] 2) When photovoltaic power generation stops at night and the power grid enters its peak electricity consumption period, peak shaving is carried out at night, and energy storage is discharged in a concentrated manner to supply user loads, replacing the high-priced grid electricity and reducing the peak load consumption of the power grid.

[0096] 3) Dynamic load matching EMS combines grid peak and valley periods and electricity price strategies to intelligently schedule charging and discharging, transferring photovoltaic daytime electricity to peak electricity consumption, effectively reducing the peak and valley load difference of the regional grid and reducing the operating burden of grid peak-shaving units.

[0097] Reduce investment in power grid construction: By implementing local balancing, load regulation, and power quality optimization, the need for grid expansion and renovation can be reduced, thereby lowering investment and operation and maintenance costs. 1) Delaying grid expansion enables photovoltaic-storage systems to achieve local power generation and consumption, significantly reducing the demand for cross-line transmission of photovoltaic power, reducing the load pressure on distribution network lines and transformers, and delaying the expansion and renovation cycle of power grid lines and substation equipment.

[0098] 2) Reduce investment in supporting equipment, energy storage to smooth power fluctuations and stabilize grid connection voltage, reduce the configuration scale and operation frequency of grid-side reactive power compensation, voltage regulation and power management equipment, and reduce related equipment procurement and maintenance costs.

[0099] 3) Replacing some of the peak-shaving and valley-filling functions of energy storage can alleviate the peak-shaving pressure on the power grid and reduce the investment in new and newly added dedicated peak-shaving units such as thermal power / energy storage.

[0100] 4) Reduce operation and maintenance costs: The system has stable power output and controllable flow direction, which reduces the workload of fault inspection and emergency repair caused by power fluctuations and reverse flow anomalies in the power grid, and reduces the power grid operation and maintenance expenses in the long term.

[0101] According to an embodiment of the present invention, in a third aspect, a building energy storage power supply system is provided, with reference to... Figures 6 to 12 This includes building rooftops and photovoltaic power supply systems.

[0102] The photovoltaic power supply system is installed on the roof of a building. The photovoltaic power generation unit 100 in the photovoltaic power supply system includes a support system 101, photovoltaic modules 102, and a drainage system 103. The support system 101 is fixed to the roof of the building and forms an elevated support structure above the roof surface; the top surface of the support system 101 forms the photovoltaic mounting surface. The photovoltaic modules 102 are laid on the photovoltaic mounting surface to convert solar energy into electrical energy. The drainage system 103 is located between the support system 101 and the photovoltaic modules 102.

[0103] The aforementioned photovoltaic power generation unit 100 is installed on the roof, occupying no ground space, adaptable to various types of buildings, and offering flexible and convenient installation. Installing the photovoltaic power generation unit 100 on the roof solves the problems of unbearable summer sun exposure and roof leaks during the rainy season. Taking the Xiaoyanglou photovoltaic module as an example, the photovoltaic module absorbs sunlight to generate electricity, effectively protecting the roof from direct sunlight and reducing the indoor temperature of the top floor by about 6ºC. Furthermore, Xiaoyanglou employs a layered vertical drainage system, greatly reducing rainwater erosion of the roof and protecting the building.

[0104] The photovoltaic modules 102 of the photovoltaic power generation unit 100 adopt a 5° overhanging and "A"-shaped double-slope design, which not only makes the structure more stable but also has a simple and beautiful appearance. The 5° overhanging and "A"-shaped slope integrates Eastern aesthetics with triangular mechanical structure. The support system 101 is made of galvanized aluminum-magnesium alloy.

[0105] The area of ​​a building's roof will affect the location and number of photovoltaic (PV) modules 102. Depending on the roof size, the PV modules 102 are arranged on the support system 101 in a vertical and / or horizontal configuration. Specifically, when the roof is relatively long and narrow, a vertical arrangement of the PV modules 102 is preferred. This maximizes the use of the narrow space and reduces ineffective gaps caused by horizontal arrangement. When the roof is wide, a horizontal arrangement is preferred, as this allows for a neater arrangement of the PV modules and facilitates subsequent maintenance and cleaning. If the roof shape is irregular, with a combination of long and narrow vertical areas and wide horizontal areas, a mixed vertical and horizontal arrangement can be used to flexibly adapt to the complex roof shape and ensure that each PV module receives the optimal angle of illumination. Furthermore, during the arrangement process, the location of obstacles such as chimneys and vents on the roof must be considered. By adjusting the installation spacing of the PV modules 102 or partially changing the arrangement direction, shading can be avoided, ensuring the power generation efficiency of the PV modules 102.

[0106] Meanwhile, the arrangement of photovoltaic modules should also match the direction of the drainage system 103 to ensure that rainwater can be discharged smoothly through the drainage system, prevent water accumulation from damaging the support system or modules, and further improve the stability and service life of the entire photovoltaic power generation unit.

[0107] When the photovoltaic modules 102 are arranged in a vertical configuration, the drainage system 103 is a four-stage water guide channel structure. For the four-stage water guide channel structure corresponding to the vertical configuration, since the photovoltaic modules 102 are arranged longitudinally along the roof, the flow path of rainwater on the surface of the photovoltaic modules 102 is relatively long. The four-stage water guide channel can gradually accelerate the rainwater discharge speed through multi-stage reception and guidance, avoid rainwater stagnation in the gaps between modules or at the bottom of the support in narrow areas, and at the same time disperse the impact force of rainwater on the water guide channel, reduce structural wear, and extend the service life of the drainage system.

[0108] When the photovoltaic modules 102 are arranged horizontally, the drainage system 103 is a three-stage water guide channel structure. For the three-stage water guide channel structure corresponding to the horizontal arrangement, since the photovoltaic modules 102 are arranged neatly in the horizontal direction, the rainwater flow span is large but the path is relatively short. The three-stage water guide channel can efficiently collect the horizontally distributed rainwater with a simpler structure, reduce unnecessary layer design, simplify the installation and maintenance process, and the reasonably spaced three-stage structure can evenly receive the rainwater from each row of photovoltaic modules, preventing local water accumulation.

[0109] When photovoltaic modules 102 are simultaneously arranged in both vertical and horizontal configurations on the support system 101, the drainage system 103 is a hybrid structure of a four-stage and a three-stage water-guiding channel. For the hybrid water-guiding channel structure corresponding to the mixed arrangement, it can be adapted to different areas of the roof, which are either longitudinally long or horizontally wide, using either a four-stage or a three-stage water-guiding channel. This ensures efficient drainage along long paths in the longitudinal area and optimizes the structure for simplified maintenance in the horizontal area. The two are connected smoothly through a transition interface design, avoiding drainage dead zones and fully adapting to the drainage needs of complex roof shapes, further improving the stability and durability of the entire system.

[0110] Reference Figure 11 The three-stage drainage channel structure includes: a longitudinal M-shaped drainage channel 1031, a transverse sub-drainage channel 1032, and a transverse main drainage channel 1033. When the photovoltaic modules 102 are arranged horizontally on the support system 101, the long sides of the photovoltaic modules 102 are arranged horizontally, and the short sides are arranged longitudinally. The transverse sub-drainage channel 1032 is located below the long side of the adjacent photovoltaic module 102, serving as the first-stage drainage channel. The longitudinal M-shaped drainage channel 1031 is located below the short side of the adjacent photovoltaic module 102, serving as the second-stage drainage channel. The longitudinal M-shaped drainage channel has an M-shaped cross-section and is connected to the photovoltaic module 102 and the support system 101 via a connecting structure 104. The longitudinal M-shaped drainage channel 1031 is located below the transverse sub-drainage channel 1032, and the longitudinal M-shaped drainage channel 1031 and the transverse sub-drainage channel 1032 are connected via a drainage outlet. A transverse main water channel 1033 is located at the edge of the roof and is connected to a longitudinal M-shaped water channel 1031.

[0111] When rainwater falls on the surface of the horizontally mounted photovoltaic modules 102, it flows laterally along the modules and gradually collects in the horizontal sub-drainage channels 1032 below the adjacent photovoltaic modules. Subsequently, the rainwater in the horizontal sub-drainage channels 1032 flows through pre-set drain outlets into the corresponding vertical M-shaped drainage channels 1031, which further concentrate the dispersed rainwater. Finally, the rainwater in the vertical M-shaped drainage channels 1031 flows into the horizontal main drainage channel 1033 located at the edge of the roof. The horizontal main drainage channel 1033, with its large volume and smooth drainage path, quickly directs the collected rainwater to the roof drain outlets or sewer pipes.

[0112] This drainage process is fully adapted to the rainwater flow characteristics of the horizontally mounted modules, and the three-stage structure works in concert to achieve efficient rainwater collection and discharge. The M-shaped cross-section of the longitudinal M-shaped water channel enhances the flow guiding capacity and effectively prevents local water accumulation; the transverse sub-water channels balance the rainwater flow of each row of photovoltaic modules, avoiding overload of a single water channel; the edge layout of the transverse main water channel ensures that rainwater is discharged from the roof in a timely manner, reducing the risk of rainwater erosion to the support system 101 and photovoltaic modules 102, and further improving the system's operational stability and durability.

[0113] In some embodiments, the photovoltaic module 102 includes a photovoltaic panel 1021 and a module frame 1022. The module frame 1022 includes a frame body and a frame base plate. The frame body is used to position the photovoltaic panel 1021, and the frame base plate is connected to the frame body.

[0114] The connection structure 104 includes a back pressure block 1041, a bracket 1042, and an adapter 1043.

[0115] The bracket 1042 includes a first positioning part 10421 and two second positioning parts 10422. The first positioning part 10421 is housed in the upper part of the longitudinal M-shaped water guide channel 1031. The top of the first positioning part 10421 supports two adjacent photovoltaic modules 102. The two second positioning parts 10422 are respectively straddling the edge of the longitudinal M-shaped water guide channel 1031.

[0116] The back pressure block 1041 includes a connecting part 10411 and an abutting part 10412. The connecting part 10411 is connected to the second positioning part 10422 of the bracket 1042 through the first locking component 1044. The abutting part 10412 presses the bottom plate of the frame onto the first positioning part 10421 of the bracket 1042.

[0117] The adapter 1043 is connected to the second positioning part 10422 of the bracket 1042 and the longitudinal M-shaped water guide channel 1031 via the second locking assembly 1045, and the adapter 1043 is connected to the support system 101 via the third locking assembly.

[0118] The fitting structure of the bracket 1042 and the longitudinal M-shaped water guide channel 1031 in this embodiment, combined with the pressing and fixing of the back pressure block 1041, makes the photovoltaic module 102 and the support system form a stable whole, effectively improving the system's wind load resistance and seismic performance, and ensuring the structural safety for long-term use. The design of the longitudinal M-shaped water guide channel 1031 not only provides a precise positioning reference for the bracket 1042, but also efficiently guides rainwater out, preventing water accumulation from corroding the modules or connecting parts and extending the service life of the equipment.

[0119] The first locking assembly 1044 and the second locking assembly 1045 can be a bolt and a nut, respectively, and the third locking assembly can be a U-shaped clamp and a nut. The adapter 1043 is L-shaped.

[0120] In some embodiments, a first positioning groove 10423 is obliquely provided on the first positioning portion 10421 of the bracket 1042, and a first protrusion 10413 is provided on the abutting portion 10412 of the back pressure block 1041. The first protrusion is inserted into the first positioning groove 10423 and locked with the first positioning groove 10423 under the action of the first locking component 1044. At least one second positioning groove 10424 is obliquely provided on the second positioning portion 10422 of the bracket 1042, and at least one second protrusion 10414 is provided on the connecting portion 10411 of the back pressure block 1041. The second protrusion is inserted into the second positioning groove and locked with the second positioning groove under the action of the first locking component 1044.

[0121] In this embodiment, the inclined first positioning groove and the first protrusion, and the second positioning groove and the second protrusion, can form a multi-dimensional limiting constraint, effectively restricting the relative sliding and rotation between the back pressure block 1041 and the bracket 1042. When the system is subjected to wind load or seismic action, the external force can be distributed to multiple contact points, avoiding local stress concentration and significantly improving the fatigue resistance of the connection parts.

[0122] In some embodiments, a limiting partition extends upward from the top of the first positioning portion 10421 of the bracket 1042. The limiting partition is disposed between two adjacent photovoltaic modules 102 to limit the distance between the two adjacent photovoltaic modules 102. The thickness of the limiting partition can be set to a thinner state, thereby reducing the distance between the two photovoltaic modules 102.

[0123] In some embodiments, a guide portion is provided on the first positioning portion 10421 of the bracket 1042 to guide water from between two adjacent photovoltaic modules 102 to the interior of the longitudinal M-shaped water channel 1031.

[0124] In some embodiments, refer to Figure 10The photovoltaic modules 102 are arranged longitudinally along the slope, and the four-level water channel structure includes: longitudinal small water channels 1034, transverse medium water channels 1035, longitudinal medium water channels 1036, and transverse main water channels 1037. The longitudinal small water channels 1034 provide the first level of waterproofing, and are located between adjacent photovoltaic modules 102, extending along the long side of each module. The transverse medium water channels 1035 provide the second level of waterproofing, and are located between adjacent rows of photovoltaic modules 102, extending along the short side of each module. The transverse medium water channels 1035 are connected to the longitudinal small water channels 1034. The longitudinal medium water channels 1036 provide the third level of waterproofing, and are spaced apart along the roof slope. The longitudinal medium water channels 1036 are connected to the transverse medium water channels 1035 through drainage outlets. The longitudinal water channels 1036 are arranged every 3 meters, and 100mm×100mm openings are made where they connect with the transverse water channels 1035. The transverse main water channel 1037 is the fourth level of waterproofing. The transverse main water channel 1037 is set at the edge of the roof and is connected to the longitudinal small water channels 1034 and the longitudinal water channels 1036. The transverse main water channel 1037 is connected to the water pipe.

[0125] The drainage principle of this embodiment is as follows: When rainwater falls on the surface of the photovoltaic module 102, it flows along the slope of the photovoltaic module 102 and first enters the longitudinal small water trough 1034 between adjacent photovoltaic modules 102; after the rainwater in the longitudinal small water trough 1034 is collected, it flows into the transverse medium water trough 1035 through the connection; the rainwater in the transverse medium water trough 1035 enters the longitudinal medium water trough 1036 through the opening opened at the junction of the transverse medium water trough 1035 and the longitudinal medium water trough 1036; finally, the rainwater in the longitudinal medium water trough 1036 and some of the rainwater that flows directly into the longitudinal small water trough 1034 are combined into the transverse main water trough 1037 set at the edge of the roof, and are discharged from the roof through the water pipe connected to the transverse main water trough 1037, forming a four-level progressive waterproof drainage path to ensure that there is no water accumulation on the roof and to ensure the stable operation of the system.

[0126] In some embodiments, the photovoltaic power generation unit 100 further includes a cleaning device connected to the drainage system 103, which is used to flush sludge deposited in the drainage system 103.

[0127] The cleaning device can be a fully automatic cleaning device. The fully automatic cleaning device can be a motor-driven scraping assembly, which is installed in a three-stage or four-stage water guiding channel structure. The motor power supply of the fully automatic cleaning device is connected to a distribution box and is powered by electricity generated by photovoltaic modules. For example, the fully automatic cleaning device can be installed in the transverse main water channel 1033 of a three-stage water guiding channel structure or in the transverse main water channel 1037 of a four-stage water guiding channel structure.

[0128] In addition, the fully automatic cleaning device can also be a flushing device connected to a three-stage or four-stage water channel structure. The flushing device is connected to one side of the water channel in the three-stage or four-stage water channel structure and flushes water to the other side of the water channel to wash away the sludge deposited in the water channel.

[0129] For the drainage system 103 with multiple layers of water tanks arranged vertically, this embodiment adds a cleaning device to the drainage system 103. This device can automatically complete the sludge removal operation of each layer of the drainage tank without requiring manual entry or climbing into the work area. This reduces the labor costs of manual maintenance and avoids the safety hazards caused by manual high-altitude operations. At the same time, the cleaning device is driven by electricity generated by the photovoltaic power generation unit itself, eliminating the need for an external municipal power supply and further reducing the system's operation and maintenance energy costs.

[0130] In some embodiments, the support system 101 includes: columns 1011, main beams 1012, purlins 1013, and decorative members 1014. Multiple columns are provided and fixed to the roof by anchors, which are expansion bolts or chemical anchors, and a waterproof layer is provided at the anchorage. The main beam is installed on top of the columns. The purlins are installed on the main beams. The decorative members are installed on the outer side of the columns.

[0131] The aforementioned building energy storage and power supply system is a distributed photovoltaic power generation system that utilizes solar panels to convert solar energy into electrical energy and integrates a power supply system and anti-reverse current protection. The system captures solar energy through photovoltaic modules and converts it into direct current (DC), which is then converted into usable alternating current (AC) by an inverter. The energy management controller in the power supply system can intelligently adjust the inverter's charging and discharging strategies based on grid electricity price signals and photovoltaic power generation signals, achieving efficient energy storage and dispatch. The anti-reverse current monitoring device monitors the grid's incoming current in real time through a current transformer. When it detects a potential reverse flow of electricity to the grid, the controller quickly adjusts the inverter's output power to ensure the system operates in accordance with grid specifications. Furthermore, the system has the ability to coordinate and interact with user-side loads, prioritizing local electricity demand. Surplus energy can be stored or connected to the grid when electricity prices are favorable, effectively improving the economy and reliability of energy utilization and providing rooftop users with a green energy solution integrating power generation, energy storage, and regulation.

[0132] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A photovoltaic power supply system, characterized in that, include: The photovoltaic power generation unit (100) has a DC output terminal; The energy storage unit (200) has a charging and discharging terminal; Battery management system; The inverter (300) has a photovoltaic DC input terminal and an energy storage DC input terminal on its DC side. The photovoltaic DC input terminal is electrically connected to the DC output terminal of the photovoltaic power generation unit (100), and the energy storage DC input terminal is electrically connected to the charging and discharging terminal of the energy storage unit (200). The AC side of the inverter (300) is connected in parallel to the power grid and user load. User load power monitoring unit, used to monitor user load power; The anti-reverse current monitoring device (400) includes an anti-reverse current monitoring unit and an energy management control unit; the current sampling terminal of the anti-reverse current monitoring unit is installed at the power grid inlet, and the signal output terminal of the anti-reverse current monitoring unit is connected to the energy management control unit; the anti-reverse current monitoring unit is used to collect current information of the power grid inlet; the energy management control unit is communicatively connected to the anti-reverse current monitoring unit, the inverter (300), the energy storage unit (200), and the user load power monitoring unit, respectively. The photovoltaic power supply system operates in two modes: surplus power fed into the grid and surplus power not fed into the grid. In the surplus power grid connection mode, the energy management control unit receives the net power of the grid incoming line reported by the anti-reverse current monitoring unit, the photovoltaic output reported by the inverter (300), the status of the energy storage unit (200) reported by the battery management system, and the user load power reported by the user load power monitoring unit. It dynamically coordinates the energy matching between the photovoltaic power generation unit, the energy storage unit, the grid, and the user load, and automatically allocates the power destination according to the preset priority. The energy management control unit executes the following energy allocation logic: photovoltaic power generation is given priority to user load; when the user load is greater than the photovoltaic output, the power gap is supplemented by the discharge of the energy storage unit, and when the charge state of the energy storage unit does not meet the discharge conditions, the grid supplies power; when the user load is less than the photovoltaic output, the surplus power is given priority to charge the energy storage unit, and after the energy storage unit is fully charged or reaches the charging limit, the remaining power is fed into the grid. In the mode where surplus power is not connected to the grid, the energy management control unit monitors the net power of the grid in real time. When it detects that the photovoltaic power generation exceeds the user's load consumption, it adjusts the output power of the inverter (300) to keep the net power of the grid in the grid at zero or a positive value.

2. The photovoltaic power supply system according to claim 1, characterized in that, The backflow prevention monitoring unit includes: Current transformers are installed on each phase line of the power grid incoming line to collect current signals and determine the current direction according to a preset transformation ratio. A bidirectional multi-function meter, connected to the current transformer, is used to collect three-phase voltage, current, active power, reactive power, power factor and power direction data, and calculate and output the net power of the incoming power grid. Wherein, when the net power of the incoming power grid is positive, it indicates that the power grid is supplying power in the forward direction; when the net power of the incoming power grid is negative, it indicates that the power is flowing back to the power grid.

3. The photovoltaic power supply system according to claim 1, characterized in that, In the surplus power grid connection mode, the energy management control unit also executes the following flexible control logic: the anti-reverse flow monitoring unit monitors the power flow direction at the grid connection point in real time and flexibly controls the output power of the inverter (300) and the charging power of the energy storage unit to avoid instantaneous power backflow impacting the grid.

4. The photovoltaic power supply system according to claim 1, characterized in that, The energy management and control unit also executes a sudden change in solar power response logic: when the photovoltaic output suddenly increases, the excess electricity is quickly stored in the energy storage unit; when the photovoltaic output suddenly decreases, the energy storage unit immediately discharges to make up for the power gap; and the rapid charging and discharging response of the energy storage unit smooths out grid-connected power fluctuations.

5. The photovoltaic power supply system according to claim 1, characterized in that, In the residual power not connected to the grid mode, the energy management control unit executes the following anti-reverse current control logic: When the net power of the incoming power grid is greater than or equal to zero, the inverter (300) maintains maximum power operation; When the net power of the grid incoming line is less than zero but greater than the preset reverse current threshold, the output power of the inverter (300) is gradually reduced; When the net power of the incoming power grid is less than or equal to the preset reverse current threshold, an emergency power reduction or shutdown operation is performed.

6. The photovoltaic power supply system according to any one of claims 1-5, characterized in that, The photovoltaic power supply system also includes a grid-connected / off-grid switching unit, which includes an automatic transfer switch (500). The control terminal of the automatic transfer switch (500) is connected to the inverter (300) or the energy management control unit. The inverter (300) also has a backup power port. The automatic transfer switch (500) includes a switch body, a normally closed position, a first normally open position, and a second normally open position. One end of the switch body is connected to the normally closed position, and the other end of the switch body is connected to the first normally open position or the second normally open position. The normally closed position is connected to the outgoing terminal of the user's inlet distribution box via a first circuit breaker. The first normally open position is connected to the incoming busbar on the grid side. The second normally open position is connected to the backup power port of the inverter (300) via a second circuit breaker. The switch body is connected to the normally closed position and the first normally open position in grid-connected mode, and the switch body is connected to the normally closed position and the second normally open position in off-grid power supply mode. When the anti-reverse current monitoring device (400) detects a grid fault, the automatic transfer switch (500) of the off-grid switching unit automatically switches to the off-grid power supply mode, and the photovoltaic power generation unit (100) and the energy storage unit (200) work together to continuously supply power to the user load; when the anti-reverse current monitoring device (400) detects that the grid has recovered, the automatic transfer switch (500) automatically switches to the grid-connected mode and returns to the grid-connected operation state.

7. A photovoltaic power supply method, characterized in that, Providing power using the photovoltaic power supply system according to any one of claims 1-6 includes the following steps: S1. The backflow prevention monitoring unit collects the electrical parameters of the incoming power grid line in real time and calculates the net power of the incoming power grid line; S2. Receive the photovoltaic output reported in real time by the inverter (300) and the status information of the energy storage unit (200) reported by the battery management system, and calculate the user load power by combining the net power of the grid incoming line; S3. Based on the current operating mode of the system, dynamically coordinate the energy flow between the photovoltaic power generation unit, the energy storage unit, and the power grid. The specific steps are as follows: Photovoltaic power generation is prioritized for use by local users. Determine the relationship between user load and photovoltaic output: When the user load exceeds the photovoltaic output, the power gap is supplemented by the discharge of the energy storage unit. When the state of charge of the energy storage unit does not meet the discharge conditions, the grid supplies power. When the user load is less than the photovoltaic output, the surplus electricity is used to charge the energy storage unit first. After the energy storage unit is fully charged or reaches the charging limit, the remaining electricity is fed into the grid. Meanwhile, the anti-backflow monitoring unit monitors the power flow direction at the grid connection point in real time, flexibly adjusting the photovoltaic output and energy storage charging power to avoid instantaneous power backflow impacting the power grid.

8. The photovoltaic power supply method according to claim 7, characterized in that, When the system is operating in surplus power grid connection mode, step S3 includes a sudden change in light intensity response step: When a sudden increase in photovoltaic output leads to an instantaneous power surplus, the excess electricity will be quickly stored in the energy storage unit; When a sudden drop in photovoltaic output leads to a power gap, the energy storage unit immediately discharges to make up for it. Smoothing grid-connected power fluctuations through the rapid charging and discharging throughput of energy storage units: And / or, when the system is operating in a mode where residual power is not connected to the grid, step S3 includes: Real-time monitoring of net power input to the power grid; When the net power is greater than or equal to zero, the inverter (300) operates at maximum power; When the net power is negative and greater than the preset reverse current threshold, the output power of the inverter (300) is gradually reduced so that the net power approaches zero. When the net power is less than or equal to the preset reverse current threshold, an emergency power reduction or shutdown operation is performed.

9. The photovoltaic power supply method according to claim 7, characterized in that, It also includes all-weather energy optimization scheduling steps: During the daytime photovoltaic power generation period, the strategy of prioritizing self-consumption, storing surplus energy, and feeding surplus power into the grid is implemented. During nighttime periods without solar power, the energy storage unit discharges to supply user loads according to peak-valley electricity pricing strategies, replacing the high-priced power grid.

10. A building energy storage power supply system, characterized in that, include: Building roof; The photovoltaic power supply system according to any one of claims 1-6 is installed on the roof of a building; The photovoltaic power generation unit (100) in the photovoltaic power supply system includes a support system (101), photovoltaic modules (102), a drainage system (103), and a cleaning device; The support system (101) is fixed to the roof of the building and forms an overhead support structure above the roof surface, and the top surface of the support system (101) forms a photovoltaic mounting surface; The photovoltaic module (102) is laid on the photovoltaic mounting surface and is used to convert solar energy into electrical energy; The drainage system (103) is disposed between the support system (101) and the photovoltaic module (102); The cleaning device is connected to the drainage system (103) and is used to flush the sludge deposited in the drainage system (103).

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