A public photovoltaic power distribution system and method based on urban lighting devices

Abstract

The application discloses a photovoltaic power distribution system and method for urban lighting devices, the system comprises a master control module and a plurality of regional power distribution units, each unit contains photovoltaic, energy storage, mains detection, switching and load grading power distribution modules. The load grading module is provided with three branches, the first level is connected with traffic lights and monitoring, the second level is connected with lighting devices, emergency broadcasting and emergency communication base station, and the third level is connected with ordinary communication base station and electronic station board. The method controls according to the mains state: when the mains is normal, the mains and energy storage power supply are switched according to the day, transition, valley power period, and charged during the valley power period; when the mains fails, the power supply is guaranteed according to the ambient light, the first and second levels are preferentially guaranteed, and the third and second sub-branches are limited or cut off. In addition, the system calculates the target brightness according to the traffic flow, light and energy storage power weight, and realizes intelligent dimming. The application improves the power supply reliability and operation energy efficiency through multi-module deployment and fine grading power supply.

Description

Technical Field

[0001] This invention relates to the field of urban lighting and photovoltaic power distribution technology, specifically to a public photovoltaic power distribution system and method based on urban lighting devices. Background Technology

[0002] With the advancement of smart city construction, the electricity demand for urban road lighting and facilities mounted on light poles, such as traffic monitoring, emergency communication, and charging piles, continues to grow. Traditional street light power distribution systems mostly rely directly on the municipal power grid for power supply. This not only results in high energy consumption and operating costs over the long term, but also means that a power outage can easily lead to complete darkness on main urban roads, seriously affecting traffic safety and causing critical security monitoring facilities to fail.

[0003] Existing solutions for introducing photovoltaic energy storage still have significant technical limitations. First, they generally lack sophisticated load classification management. When the grid power is interrupted, all types of loads are supplied equally, causing the energy storage batteries to be depleted prematurely due to supplying unnecessary loads, making it impossible to ensure the continuous operation of critical facilities such as traffic monitoring. Second, the multi-source power supply switching logic is relatively crude, failing to combine peak and off-peak electricity pricing periods and the remaining battery power for optimal coordinated scheduling, resulting in low utilization rates of photovoltaics and energy storage. Third, most lighting dimming strategies only consider the single factor of ambient light, failing to organically integrate factors such as traffic flow and battery power, making it difficult to balance energy conservation and safety.

[0004] In summary, existing technologies still have shortcomings in terms of energy coordinated dispatch, load classification protection, and intelligent dimming, making it difficult to meet the comprehensive requirements of smart cities for high reliability and high economy. There is an urgent need for an urban lighting photovoltaic power distribution system and method that can achieve seamless switching between multiple sources, load classification protection, and multi-dimensional linkage dimming. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a shared photovoltaic power distribution system and method based on urban lighting devices. By adopting a modular architecture that coordinates multiple regional power distribution units with a main control module, the photovoltaic power flow and load hierarchical control are optimized, and multi-mode intelligent switching logic is designed, which significantly improves the system's energy utilization efficiency, operating economy and power supply reliability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: On the one hand, the present invention provides a public photovoltaic power distribution system based on urban lighting, including a main control module and several groups of regional power distribution units. Each group of regional power distribution units is independently deployed in a corresponding area and is only used to provide power distribution to public power facilities in the corresponding area. Each of the aforementioned regional power distribution units includes a photovoltaic power generation module, an energy storage module, a mains power detection module, a switching module, several lighting devices, and a load-level power distribution module; The photovoltaic power generation module includes a photovoltaic control unit and a number of photovoltaic modules that are installed one-to-one with a number of lighting devices in the corresponding area. The photovoltaic modules are electrically connected to the energy storage module via the photovoltaic control unit. The AC output terminal of the energy storage module and the mains power grid are both connected in parallel to the common input terminal of the load-level distribution module through a switching module; The input terminal of the mains power detection module is connected to the mains power, and the output terminal is electrically connected to the switching module; the load distribution module includes at least three independent load output branches, and each branch is equipped with a controllable switch controlled by the main control module; The main control module is communicatively connected to the energy storage module, switching module, photovoltaic control unit, mains power detection module, lighting control unit, and controllable switch in the load-level distribution module of each group of regional power distribution units.

[0007] Furthermore, each energy storage module in the regional power distribution unit includes an energy storage battery, a bidirectional converter, and a battery management unit electrically connected to the energy storage battery; the output terminal of the photovoltaic control unit is simultaneously connected to the charging terminal of the energy storage battery and the DC side of the bidirectional converter; the discharging terminal of the energy storage battery is connected to the DC side of the bidirectional converter; the AC side of the bidirectional converter is the AC output terminal of the energy storage module; and the battery management unit is communicatively connected to the main control module.

[0008] Furthermore, the public power facilities are divided into three levels, and the three independent load output branches include a first load output branch, a second load output branch, and a third load output branch; wherein, the first load output branch connects to the primary load, which includes traffic lights and monitoring devices in the corresponding area; the second load output branch connects to the secondary load, which includes lighting devices, emergency broadcasts, and emergency communication base stations; and the third load output branch connects to the tertiary load, which includes ordinary communication base stations and electronic bus stop signs.

[0009] Furthermore, the second load output branch of the load distribution module includes at least two independent sub-branches, each of which is equipped with a controllable switch controlled by the main control module.

[0010] On the other hand, the present invention provides a public photovoltaic power distribution method based on urban lighting, applied to the above-mentioned system, comprising: Real-time acquisition of the current time period, the remaining power of the energy storage battery, and the mains power status of the corresponding area collected by the mains power detection module; When the mains power is normal, the current time period will apply: During the daytime hours, power is supplied to the first, second, and third loads of multiple regional power distribution units via mains power; During the transition period, when the remaining power of the energy storage battery is greater than the first power threshold, the control switching module switches to the energy storage module, and the energy storage battery is converted into AC power by a bidirectional converter to supply power to the lighting device and various loads until the remaining power drops to the second power threshold, at which point the mains power is restored to supply power to the lighting device and various loads; when the remaining power of the energy storage battery is not greater than the first power threshold, the mains power is used to supply power to the lighting device and various loads; wherein, the first power threshold is greater than the second power threshold; During off-peak hours at night, the mains power supply provides power to lighting fixtures and loads at all levels, and controls the bidirectional converter to charge the energy storage battery; When the mains power fails, the control switching module switches to the energy storage module to provide power during the fault: If the ambient light meets the lighting conditions, control the bidirectional converter to invert the power supply to maintain the power supply of the lighting device and the first load output branch, limit the power and / or disconnect the second load output branch according to the remaining power, and disconnect the third load output branch. If the ambient light does not meet the conditions for turning on the lighting, the lighting device is turned off. The photovoltaic module supplies power to the first and second load output branches through the bidirectional converter. The insufficient power is supplemented by the energy storage battery. The third load output branch is immediately cut off, and the power of the second load output branch is limited and / or cut off according to the remaining power.

[0011] Furthermore, it also includes an automatic lighting brightness adjustment step: Collect traffic flow parameters T, ambient light intensity parameters I, and the remaining state of charge (SOC) of the energy storage battery; determine the target brightness using the following formula: L=Ln×[α×f(T)+(1-α)×g(I)]×h(SOC); Where Ln is the rated brightness of the lighting device, α is the traffic flow weight, and α > 0.5, f(T) is the normalized function that increases with traffic flow, and g(I) is the normalized function that decreases with light intensity; when the mains power is normal, h(SOC) = 1, and when the mains power fails, h(SOC) is a function that is positively correlated with SOC. The target brightness is sent to each lighting control unit to adjust the brightness of the lighting device.

[0012] Furthermore, it also includes: when the grid voltage is detected to have recovered to 90% to 110% of the rated voltage and remained stable for a preset duration, the corresponding power supply status is restored according to the current time period.

[0013] Furthermore, the transition period is the period from the end of the daytime period to the beginning of the off-peak period at night, during which the power generation of the photovoltaic modules is lower than a preset threshold.

[0014] Furthermore, the step of limiting and / or disconnecting the second load output branch based on the remaining power includes: When the remaining power is higher than the first power threshold, the second load output branch is kept powered normally. When the remaining power is lower than the first power threshold, the power supply of the second load output branch is limited; When the remaining power is lower than the second power threshold, each sub-branch in the second load output branch is disconnected one by one.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Multi-regional modular deployment: The main control module coordinates multiple regional power distribution units, each operating relatively independently. A power outage or equipment failure in one group only affects the corresponding adjacent area, preventing a complete power outage and significantly improving the disaster recovery and resilience of the urban power distribution system.

[0016] 2. Multi-source coordination and seamless switching: Through the unified scheduling of the mains power switching module and the main control module, coordinated power supply and seamless switching of mains power, photovoltaic and energy storage are realized to ensure power supply continuity.

[0017] 3. Time-based energy saving optimization: Implement differentiated power supply and charging strategies for daytime, transitional, and off-peak electricity periods to make full use of photovoltaic power and low off-peak electricity prices and reduce operating costs; use hysteresis control during transitional periods to avoid frequent fluctuations in power supply mode.

[0018] 4. Fault-based power supply: In the event of a mains power failure, the system automatically prioritizes power supply according to the first, second, and third level of loads, giving priority to critical loads and gradually limiting or cutting off secondary loads based on the remaining power, effectively extending the critical power supply time in the off-grid state.

[0019] 5. Intelligent linkage dimming: The lighting brightness is adjusted by a weighted average of traffic flow, ambient light, and energy storage capacity, with clear priorities, taking into account traffic safety, energy saving, and battery life. Attached Figure Description

[0020] Figure 1 This is a structural block diagram of the photovoltaic power distribution system of the present invention; Figure 2 This is a structural block diagram of the main control module of the present invention; Figure 3 This is an overall flowchart of the photovoltaic power distribution method for urban lighting according to the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.

[0022] like Figure 1 and Figure 2 As shown, the present invention provides a shared photovoltaic power distribution system based on urban lighting devices, which mainly includes a main control module and several groups of regional power distribution units deployed in different adjacent geographical areas of the city. Each group of regional power distribution units is independently deployed in the corresponding area and is only used to provide power distribution to public power facilities in the corresponding area. Each area distribution unit includes a photovoltaic power generation module, several lighting devices corresponding to the photovoltaic power generation module, and an energy storage module, a mains power detection module, a switching module, and a load-level distribution module located in the corresponding area's public distribution box.

[0023] The photovoltaic power generation module includes a photovoltaic control unit and several photovoltaic modules; the photovoltaic modules are monocrystalline silicon or polycrystalline silicon photovoltaic modules, installed on the top of the street light poles in the corresponding area. The photovoltaic control unit is an MPPT (Maximum Power Point Tracking) controller, which tracks the maximum output power of the photovoltaic modules in real time. Its output is divided into two paths: one path is connected to the DC charging port of the energy storage battery in the energy storage module, and the other path is connected to the DC input port of the bidirectional converter.

[0024] The energy storage module includes an energy storage battery, a battery management unit, and a bidirectional converter. The battery management unit is responsible for real-time acquisition of the battery's voltage, current, temperature, and calculation of remaining power. The data is sent to the main control module via an RS485 bus and features overcharge, over-discharge, and over-temperature protection. The bidirectional converter supports both rectification and inversion operation, and its rated power is matched to the total load capacity of the area.

[0025] The input terminal of the mains power detection module is connected to the local mains power grid and has over / under voltage, over / under frequency, phase loss, and anti-islanding detection functions. It is typically configured as follows: when the detected mains voltage is lower than 85% of the rated value or higher than 115% of the rated value, the frequency is lower than 49.5Hz or higher than 50.5Hz, and the duration exceeds 1 second, a mains power fault is determined, and the fault signal is immediately transmitted via hard-wired direct control to disconnect the switching module, while simultaneously notifying the main control module via the data bus.

[0026] The core component of the switching module is an AC contactor with a shunt trip unit. When a fault signal is received from the mains power detection module or a disconnect command is received from the mains control module, the contactor trips, cutting off the mains power supply and electrically isolating the subsequent loads from the mains power grid, thus switching to islanded operation. When the mains power is restored and synchronization is completed, the main control module outputs a closing signal, and the contactor engages.

[0027] Regarding the load-level power distribution module, its common input terminal receives electrical energy from the switching module and performs precise control through three independent output branches; The first load output branch is connected to the primary load, which includes traffic lights and security / traffic monitoring devices at the corresponding traffic intersections in the area, and has the highest priority. The second load output branch connects to the secondary load, which includes the street lighting equipment, emergency broadcasting and emergency communication base station in this area, and is a secondary important load; The third load output branch connects to the third-level load, which includes ordinary civilian communication base stations and electronic bus stop signs, as non-essential loads that can be interrupted at any time.

[0028] The second load output branch also contains two independent sub-branches, each of which is equipped with a controllable switch controlled by the main control module, so as to perform more delicate step-by-step disconnection when the power is tight.

[0029] The lighting control unit is connected in series with the power input terminal of each lighting device. It integrates a PWM dimming driver and can accept brightness commands sent by the main control module via Modbus or LoRa wireless communication. The output power adjustment range is 20%-100%.

[0030] The main control module adopts an industrial-grade PLC or a high-performance embedded microprocessor, with an integrated RTC real-time clock chip. It has multiple analog input and digital output input interfaces, and is responsible for coordinating the logical operation of the entire multi-group system. It receives data from each group of mains power detection modules and each battery management unit, and issues instructions to each group of switching modules, controllable switches and lighting control units.

[0031] like Figure 3 As shown, the power distribution method provided by this invention is applied to the above-mentioned multiple systems, specifically including: S1. System Initialization and Parameter Acquisition: After the system is powered on, the main control module acquires the current time of each group of regional power distribution units, the mains power parameters transmitted by the mains power detection module, the remaining power of the energy storage battery uploaded by the battery management unit, the photovoltaic power generation and ambient light intensity uploaded by the photovoltaic control unit, and the traffic flow parameters transmitted by the traffic monitoring system in real time through the bus. S2. Mains Power Status Judgment and Power Supply Mode Switching: The main control module determines whether each group of mains power is normal based on the parameters collected by the mains power detection unit. When the mains voltage of the group is within 90%-110% of the rated value and the frequency is within 49.5Hz-50.5Hz, it is determined that the mains power is normal; otherwise, it is determined that the mains power is faulty, and step S22 is executed.

[0032] S21. When the mains power is normal, the main control module executes the corresponding power supply logic according to the current time period: During daytime hours (e.g., 6:00-18:00, which can be adjusted according to local sunrise and sunset times): Power is supplied to the first, second, and third loads from the municipal power grid. At this time, ambient light intensity is sufficient, and lighting fixtures remain off. The electricity generated by the photovoltaic modules directly charges the energy storage battery through the photovoltaic control module until the remaining charge of the energy storage battery reaches 100%. At this point, the photovoltaic control module automatically limits the photovoltaic output power. Lighting fixtures are usually off during this period, only being turned on when the light intensity falls below the activation threshold due to special weather conditions.

[0033] Transition period (e.g., 18:00-22:00, adjustable according to local sunset time and off-peak electricity start time): This stage is from the end of daytime to the start of off-peak electricity at night, and photovoltaic output is relatively low. The system assesses the energy storage battery. To reduce electricity costs, if the remaining charge of the energy storage battery is greater than the first threshold, the main control module controls the mains power switching module to disconnect, and the energy storage battery is powered by inverter through a bidirectional converter. As the SOC drops to the second threshold due to discharge, the main control module controls the mains power switching module to close again, restoring mains power supply.

[0034] Transition period (e.g., 18:00-22:00, adjustable according to local sunset time and off-peak electricity start time): This period is from the end of the daytime session to the beginning of the nighttime off-peak electricity session, and the photovoltaic module power generation is below a preset threshold, with lighting devices turned on. The main control module determines the remaining power of the energy storage battery. At this time, the main control module determines the remaining power of the energy storage battery: If the remaining power is greater than the first power threshold, the mains switching module is controlled to disconnect from the mains power grid and switch to the energy storage module for power supply. The energy storage battery is inverted into AC power by a bidirectional converter to supply power to the lighting device and loads at all levels. When the remaining power of the energy storage battery drops to the second power threshold, the mains switching module is controlled to close again and restore the mains power grid to supply power to the lighting device and loads at all levels. If the remaining power is not greater than the first power threshold, the mains power switching module remains closed, and the mains power grid supplies power to the lighting device and loads at all levels; wherein the first power threshold is greater than the second power threshold.

[0035] During off-peak hours at night (e.g., 22:00-6:00 the next day, subject to adjustment according to the off-peak hours published by the local power grid): power is supplied to lighting devices and loads at all levels from the mains grid; at the same time, the main control module controls the bidirectional converter to work in rectification mode, converting the AC mains power into DC power to charge the energy storage battery with constant current and constant voltage until the remaining power of the energy storage battery reaches 100% and then charging stops.

[0036] S22. When the mains power fails in this group, the main control module immediately controls the switching module to disconnect, switches to the energy storage module, and executes the following emergency power supply logic: If the ambient light meets the lighting requirements: control the bidirectional converter to supply power, prioritizing the primary and secondary loads. Immediately disconnect the tertiary load, and limit or gradually disconnect the sub-branch of the secondary load based on the remaining power.

[0037] If ambient light levels do not meet the conditions for lighting activation: Considering the lack of lighting demand, the main control module shuts down the lighting device. At this time, the photovoltaic modules prioritize supplying power directly to the primary load and secondary loads (excluding lighting) via a bidirectional converter, with any shortfall supplemented by the energy storage battery. The tertiary load is immediately disconnected, and the power of secondary loads is still limited or disconnected based on remaining power, maximizing the operating time of traffic lights and monitoring devices.

[0038] S3. Automatic Lighting Brightness Adjustment: During the period when the lighting device is on, the main control module executes the automatic lighting brightness adjustment procedure in real time: S31. Collect the traffic flow parameter T, ambient light intensity parameter I, and remaining battery charge SOC of the corresponding area; S32. Calculate the target luminance L of the lighting device using the following formula: L=L n ×[α×f(T)+(1-α)×g(I)]×h(SOC); Where: L n α represents the rated brightness of the lighting device; α is the traffic flow weight, ranging from 0.6 to 0.8, ensuring that the impact of traffic flow on brightness is greater than that of light intensity; f(T) is a normalized function that increases with traffic flow, ranging from 0.2 to 1.0; g(I) is a normalized function that decreases with light intensity, ranging from 0 to 1.0; h(SOC) is the energy storage capacity adjustment coefficient. When the mains power is normal, h(SOC) = 1, and the impact of energy storage capacity on brightness is not considered; when the mains power fails, h(SOC) is a function positively correlated with SOC, ranging from 0.2 to 1.0. S33. The calculated target brightness L is sent to each lighting control unit, and the lighting control unit adjusts the output brightness of the lighting device to the target value.

[0039] S41. Control the bidirectional converter to adjust its output voltage, phase and frequency so that it is completely synchronized with the mains power grid, with a synchronization error ≤1°. S42, Close the mains power switching module to achieve seamless switching between mains power and energy storage module, avoiding inrush current; S43. Based on the current time and light intensity, determine whether to revert to daytime mode, transition mode, or off-peak nighttime mode; S44. Following the order from most important to least important, gradually close the controllable switches of the disconnected secondary load sub-branch and the third load output branch to restore full load power supply.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A photovoltaic power distribution system based on urban lighting devices, characterized in that, It includes a main control module and several sets of regional power distribution units. Each set of regional power distribution units is independently deployed in a corresponding area and is only used to provide power distribution to public power facilities in that corresponding area. Each of the aforementioned regional power distribution units includes a photovoltaic power generation module, an energy storage module, a mains power detection module, a switching module, several lighting devices, and a load-level power distribution module; The photovoltaic power generation module includes a photovoltaic control unit and a number of photovoltaic modules that are installed one-to-one with a number of lighting devices in the corresponding area. The photovoltaic modules are electrically connected to the energy storage module via the photovoltaic control unit. The AC output terminal of the energy storage module and the mains power grid are both connected in parallel to the common input terminal of the load distribution module through the switching module; The input terminal of the mains power detection module is connected to the mains power, and the output terminal is electrically connected to the switching module; The load distribution module includes at least three independent load output branches, each of which is equipped with a controllable switch controlled by the main control module. The main control module is communicatively connected to the energy storage module, switching module, photovoltaic control unit, mains power detection module, lighting control unit, and controllable switch in the load-level distribution module of each group of regional power distribution units.

2. The public photovoltaic power distribution system according to claim 1, characterized in that, Each energy storage module in the regional power distribution unit includes an energy storage battery, a bidirectional converter, and a battery management unit electrically connected to the energy storage battery; the output terminal of the photovoltaic control unit is simultaneously connected to the charging terminal of the energy storage battery and the DC side of the bidirectional converter; the discharging terminal of the energy storage battery is connected to the DC side of the bidirectional converter; the AC side of the bidirectional converter is the AC output terminal of the energy storage module; the battery management unit is communicatively connected to the main control module.

3. The photovoltaic power distribution system according to claim 1, characterized in that, The public power facilities are divided into three levels. The three independent load output branches include a first load output branch, a second load output branch, and a third load output branch. The first load output branch connects to the primary load, which includes traffic lights and monitoring devices in the corresponding area. The second load output branch connects to the secondary load, which includes lighting devices, emergency broadcasts, and emergency communication base stations in the corresponding area. The third load output branch connects to the tertiary load, which includes ordinary communication base stations and electronic bus stop signs in the corresponding area.

4. The photovoltaic power distribution system according to claim 3, characterized in that, The second load output branch of the load distribution module includes at least two independent sub-branches, each of which is equipped with a controllable switch controlled by the main control module.

5. A public photovoltaic power distribution method based on urban lighting, characterized in that, Applied to the system according to any one of claims 1-4, comprising: Real-time acquisition of the current time period, the remaining power of the energy storage battery, and the mains power status of the corresponding area collected by the mains power detection module; When the mains power is normal, the current time period will apply: During the daytime hours, power is supplied to the first, second, and third loads of multiple regional power distribution units via mains power; During the transition period, when the remaining power of the energy storage battery is greater than the first power threshold, the mains power switching module is controlled to switch to the energy storage module. The energy storage battery is then inverted into AC power via a bidirectional converter to supply power to the lighting device and various loads until the remaining power drops to the second power threshold, at which point the mains power supply to the lighting device and various loads is restored. When the remaining power of the energy storage battery is not greater than the first power threshold, the mains power supply is used to supply power to the lighting device and various loads. Wherein, the first power threshold is greater than the second power threshold. During off-peak hours at night, the mains power supply provides power to lighting fixtures and loads at all levels, and controls the bidirectional converter to charge the energy storage battery; When the mains power fails, the mains power switching module switches to the energy storage module to provide power during the fault: If the ambient light meets the lighting conditions, control the bidirectional converter to invert the power supply to maintain the power supply of the lighting device and the first load output branch, limit the power and / or disconnect the second load output branch according to the remaining power, and disconnect the third load output branch. If the ambient light does not meet the conditions for turning on the lighting, the lighting device is turned off. The photovoltaic module supplies power to the first and second load output branches through the bidirectional converter. The insufficient power is supplemented by the energy storage battery. The third load output branch is immediately cut off, and the power of the second load output branch is limited and / or cut off according to the remaining power.

6. The photovoltaic power distribution method according to claim 5, characterized in that, It also includes an automatic brightness adjustment step: Collect traffic flow parameters T, ambient light intensity parameters I, and the remaining state of charge (SOC) of the energy storage battery; determine the target brightness using the following formula: L=L n ×[α×f(T)+(1-α)×g(I)]×h(SOC); Among them, L n Let be the rated brightness of the lighting device, α be the traffic flow weight, and α > 0.5, f(T) be a normalized function that increases with traffic flow, and g(I) be a normalized function that decreases with light intensity; when the mains power is normal, h(SOC) = 1, and when the mains power fails, h(SOC) is a function positively correlated with SOC. The target brightness is sent to each lighting control unit to adjust the brightness of the lighting device.

7. The photovoltaic power distribution method according to claim 5, characterized in that, Also includes: Once the grid voltage is detected to have recovered to 90%–110% of the rated voltage and remained stable for a preset duration, the corresponding power supply status will be restored according to the current time period.

8. The photovoltaic power distribution method according to claim 5, characterized in that, The transition period is the period from the end of the daytime period to the beginning of the off-peak period at night, during which the power generation of the photovoltaic modules is lower than a preset threshold.

9. The photovoltaic power distribution method according to claim 5, characterized in that, The method of limiting and / or disconnecting the second load output branch based on the remaining power includes: When the remaining power is higher than the first power threshold, the second load output branch is kept powered normally. When the remaining power is lower than the first power threshold, the power supply of the second load output branch is limited; When the remaining power is lower than the second power threshold, each sub-branch in the second load output branch is disconnected one by one.

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