Outdoor electronic station board and shelter for bus stop with anti-shading solar power supply system

Abstract

This invention discloses an anti-shading solar power supply system for outdoor electronic bus stop signs and shelters. It includes multiple sets of photovoltaic power generation units, each consisting of at least two solar photovoltaic panels connected independently in parallel with positive terminals connected to each other and negative terminals connected to each other, with no series connection between the power generation units. It also includes multiple independent PWM solar controllers, each with its input terminal electrically connected to only one set of power generation units, and each PWM controller is electrically independent. This invention employs multiple independent PWM solar controllers, each corresponding to a set of power generation units with multiple independently connected photovoltaic panels. The power generation units are not connected in series and generate electricity independently. When any photovoltaic panel is shaded by a building or tree, or its surface is partially covered by leaves, dust, bird droppings, or other substances, only the power generation power of the unit containing that photovoltaic panel is affected; other power generation units continue to operate normally.

Description

Technical Field

[0001] This invention relates to the field of solar power supply system technology, specifically to an anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters. Background Technology

[0002] Against the backdrop of smart city and green transportation development, outdoor electronic bus stop signs and smart bus shelters, as core terminals for public transportation information services, require stable and reliable power supply systems. Currently, these outdoor facilities widely adopt solar power systems to achieve energy conservation and independent operation. In existing technologies, a common approach is to use a series-connected photovoltaic module structure, where multiple photovoltaic panels are connected in series to form a photovoltaic array, which is then connected to one or a few solar controllers to charge batteries and ultimately power loads (such as LCD displays and lighting fixtures).

[0003] However, in real-world, complex outdoor applications, this traditional series-connected solar power system suffers from a series of interconnected and difficult-to-overcome technical drawbacks: Firstly, partial shading causes a sharp drop in the overall power generation efficiency of the photovoltaic (PV) string. In a traditional series structure, the output current of a PV module is limited by the module with the lowest current in the string. When any PV panel is partially shaded by surrounding buildings, trees, or other objects, the output current of that module decreases significantly, resulting in limited current in the entire series circuit and an exponential decrease in total power generation. This "shading-induced weakness" effect drastically shortens the effective power generation time of the system under complex lighting conditions, making it difficult to meet the demand for all-weather power supply.

[0004] Furthermore, localized contamination of solar panels can easily trigger hot spot effects, leading to string failure or even damage. Outdoor environments inevitably attract pollutants such as leaves, dust, and bird droppings, which can adhere to the surface of photovoltaic panels. In a series structure, contaminated photovoltaic panels are forced to operate in a reverse bias state due to localized current limitation, forming high-resistivity areas and thus generating hot spot effects. Hot spots not only drastically reduce the overall string's power generation efficiency, causing "one-time shutdown" power outages, but also accelerate localized aging of the photovoltaic panels, burn out encapsulation materials, and in severe cases, may cause permanent damage to the modules or fire risks, significantly reducing system safety and lifespan.

[0005] Furthermore, when the platform load power consumption is high, the solar power supply capacity is insufficient. Traditional electronic bus stop signs mostly use ordinary backlit LCD displays, and bus shelter lighting often uses anode common anode LED tubes, both of which have the problem of high power consumption. On cloudy or rainy days or in seasons with insufficient sunlight, the power generation of the solar system is already limited, and the high power load further aggravates the rapid discharge of the battery, resulting in a serious lack of power supply capacity and frequent system shutdowns at night or after consecutive cloudy days.

[0006] Existing series-connected power structures have low reliability, and a single point of failure can easily lead to a complete power outage. In the traditional single-path series architecture, whether it is a photovoltaic panel causing abnormal output due to shading or pollution, or a fault in a section of line or a connector, the power generation path of the entire photovoltaic array will be directly cut off, causing a complete system shutdown. This "single point of failure, global failure" topology cannot meet the reliability requirements of outdoor electronic bus stop signs and waiting shelters for long-term, uninterrupted power supply.

[0007] Traditional integrated photovoltaic arrays typically require customized brackets, complex junction boxes, and combiner boxes. Installation involves extensive high-altitude work and wiring, resulting in long construction periods and high costs. In later operation and maintenance, because the series structure requires highly consistent performance across all components, a performance degradation in one component often necessitates a complete inspection or even replacement of the entire array. Furthermore, to prevent localized contamination from affecting the entire string, frequent overall cleaning is essential, leading to significant workload and high costs. Overall, the current technology has relatively high initial and long-term operating costs.

[0008] In summary, existing traditional series-connected solar power technology, when applied to outdoor electronic bus stop signs and smart bus shelters, struggles to simultaneously address multiple issues related to shading tolerance, pollution resistance, load power consumption, power supply stability, ease of installation, and economical maintenance while maintaining low cost. Therefore, there is an urgent need to develop a new type of solar power system that is shading-resistant, pollution-resistant, energy-efficient, stable, integrates power supply, is easy to install, and has low maintenance costs. Summary of the Invention

[0009] To solve the above-mentioned technical problems, the present invention provides an anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters, which has the characteristics of anti-shading, anti-pollution, energy saving and stability.

[0010] To achieve the above objectives, the present invention provides the following technical solution: an anti-shading solar power supply system for outdoor electronic bus stop signs and shelters, comprising: Multiple photovoltaic power generation units, each consisting of at least two solar photovoltaic panels connected independently in parallel with positive terminals connected to positive terminals and negative terminals connected to negative terminals, and no series connection between the power generation units; Multiple independent PWM solar controllers, each PWM controller's input terminal is electrically connected to only one set of power generation units, and each PWM controller is electrically independent of the others; The input terminal of the lithium iron phosphate battery energy storage module is connected in parallel with the output terminal of the multi-channel independent PWM controller. The control module is powered by the lithium iron phosphate battery; A dynamic backlit energy-saving LCD screen is installed inside the electronic bus stop sign and is controlled by a control module. Common cathode LED energy-saving tubes are installed in the smart bus shelter and controlled by the control module; The outputs of the multiple independent PWM controllers are connected in parallel and combined to charge the lithium iron phosphate battery; the lithium iron phosphate battery, through the control module, supplies power to the dynamic backlight energy-saving LCD screen and the common cathode LED energy-saving lamp respectively; When any solar photovoltaic panel is partially blocked by an external obstruction or its surface is covered by pollutants, only the output power of the power generation unit to which that photovoltaic panel belongs decreases, while the other power generation units continue to generate power independently and normally, and the overall output power of the system remains uninterrupted.

[0011] As a preferred technical solution of the anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters of the present invention, each of the multiple photovoltaic power generation units has 2 to 6 photovoltaic panels connected in parallel inside, and the electrical parameters of each photovoltaic panel in the same group are consistent. Each power generation unit and its corresponding PWM controller, as well as the output terminals of each PWM controller and the lithium iron phosphate battery, are connected by independently laid DC power cables. Each cable is a 2×4 square millimeter copper core cable. Each group of cables is laid independently along the inner side of the roof of the bus shelter or in the cable tray, and they are not connected to each other.

[0012] As a preferred technical solution of the anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters of the present invention, the multi-channel independent PWM solar controllers each integrate an independent MPPT or PWM charging management circuit, and have functions of voltage regulation, current limiting, reverse charging protection and overcharge protection; there is no electrical series connection between the controllers, and when a single controller fails or the corresponding power generation unit is abnormal, the other controllers continue to work normally.

[0013] As a preferred technical solution of the anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters of the present invention, the lithium iron phosphate battery energy storage module integrates a BMS battery management circuit. This BMS circuit has at least the functions of overcharge protection, over-discharge protection, overcurrent protection, short circuit protection and battery temperature monitoring.

[0014] As a preferred technical solution of the outdoor electronic bus stop sign and anti-shading solar power supply system for bus shelters according to the present invention, the solar photovoltaic panel is directly fixedly installed on the roof of the bus shelter by a high and low bracket; the front end of the high and low bracket is lower than the rear end, so that the photovoltaic panel forms an inclined angle facing the sun; the bottom of the bracket is fixedly connected to the roof of the bus shelter by bolts or welding. The inclination angle of the high and low supports is 15° to 45°. The supports are made of galvanized steel or aluminum alloy profiles and have an anti-corrosion coating on their surface.

[0015] As a preferred technical solution of the anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters of the present invention, the dynamic backlight energy-saving LCD screen has a built-in backlight driving circuit, and the control module includes an ambient light sensor, a battery power detection circuit and an MCU processor; the MCU processor dynamically adjusts the backlight PWM duty cycle of the LCD screen according to the ambient illuminance value collected by the ambient light sensor, the current power of the lithium iron phosphate battery collected by the battery power detection circuit, and the current power generation obtained through the communication interface, so as to realize adaptive energy-saving control of the backlight brightness.

[0016] As a preferred technical solution of the anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters of the present invention, the common cathode LED energy-saving lamp tube adopts a common cathode driving architecture, that is, the cathodes of all LED beads are connected to the negative terminal of the power supply, and the anodes are independently controlled by constant current driving chips. The control module includes an ambient light illuminance sensor and a battery power detection circuit. According to the illuminance value collected by the ambient light illuminance sensor, the control module divides the working state of the lamp tube into four levels: fully off during the day, low brightness at dusk, full brightness at night, and half brightness at night. At the same time, when the battery power is lower than a preset threshold, the control module forces the lamp tube to switch to a lower brightness level.

[0017] As a preferred technical solution of the anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters according to the present invention, the system includes the following steps: Step S1: Divide all solar photovoltaic panels into N independent parallel power generation units, with positive photovoltaic panels connected positively and negative photovoltaic panels connected negatively within each unit; Step S2: Connect the N groups of power generation units to N electrically independent PWM solar controllers respectively; Step S3: Connect the output terminals of the N-channel PWM controllers in parallel to the charging input terminal of the lithium iron phosphate battery; Step S4: The lithium iron phosphate battery supplies power to the dynamic backlight energy-saving LCD screen and the common cathode LED energy-saving lamp tube respectively via the control module; Step S5: When any photovoltaic panel is partially shaded or its surface is contaminated, the output power of the power generation unit where the photovoltaic panel is located decreases, but the PWM controller corresponding to this unit independently reduces its charging current, while the other N-1 controllers maintain their original charging state, and the overall power supply of the system is not interrupted. Step S6: The control module collects ambient illuminance, battery power, and current total power generation in real time; Step S7: When the total power generation is lower than the first threshold and the battery power is lower than the second threshold, the control module first reduces the backlight brightness of the dynamic backlight energy-saving LCD screen. If the power supply balance is still not met, the brightness level of the common cathode LED energy-saving lamp tube is reduced step by step. Step S8: When the total power generation recovers to above the third threshold and the battery power recovers to above the fourth threshold, the control module gradually restores the brightness of the lamps and the backlight of the screen.

[0018] As a preferred technical solution of the outdoor electronic bus stop sign and waiting shelter anti-shading solar power supply system of the present invention, the control module also integrates a wireless communication unit for remotely uploading system operating status parameters to the monitoring platform. The operating status parameters include: real-time power generation of each power generation unit, battery power, load power consumption and working status of each PWM controller.

[0019] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention employs a multi-channel independent PWM solar controller, with each channel corresponding to a group of internally connected photovoltaic panels forming an independent power generation unit. These units are not connected in series and generate electricity independently. When any photovoltaic panel is shaded by buildings or trees, or partially covered by leaves, dust, bird droppings, or other materials, only the power generation of that photovoltaic panel's unit is affected; other units continue to operate normally. Compared to the fatal flaw of traditional series structures—"weakened by shading, stopped by covering"—this invention maintains most of its power generation capacity even under complex outdoor lighting conditions, ensuring uninterrupted operation of electronic bus stop displays and waiting shelter lighting.

[0020] 2. The technical solution of this invention completely avoids the risk of hot spots, significantly improving system safety and service life. In traditional series structures, local contamination can easily lead to reverse bias of the photovoltaic panel, forming hot spots, causing high-temperature ablation or even fire. This invention, however, adopts a multi-path independent parallel structure, with no series connection between each photovoltaic panel (or each group of internally connected photovoltaic panels). Contamination of any single photovoltaic panel will not become a high-resistance point in the circuit, fundamentally eliminating the conditions for hot spot effects. System safety is qualitatively improved, and the service life of the photovoltaic modules and the entire power supply system is significantly extended.

[0021] 3. In this invention, each PWM solar controller independently adjusts the charging parameters of its corresponding power generation unit, and the outputs of each controller are connected in parallel to the lithium iron phosphate battery. This topology ensures that even if a single controller or a single power generation unit fails, the remaining controllers can still generate and charge normally, preventing the entire power supply system from failing. Compared to the fragile architecture of traditional single controllers or series paths with "single point of failure, global failure," this invention has extremely high fault tolerance and is particularly suitable for long-term unattended outdoor operation.

[0022] 4. The system in this invention can uniformly power both the dynamic backlight energy-saving LCD screen and the common-cathode LED energy-saving lamps. The dynamic backlight technology can automatically adjust the backlight power consumption according to the ambient brightness and the displayed content. Compared with traditional common-anode lamps, the common-cathode LED lamps have higher power supply efficiency and lower heat generation. The combination of the two reduces the total power consumption at the load end by more than 30% compared with traditional solutions. Under the same photovoltaic power generation and energy storage capacity, the system's endurance is significantly enhanced, and it can easily cope with several consecutive days of cloudy and rainy weather.

[0023] 5. The solar power supply system in this invention simultaneously supports the power supply for the dynamic backlit energy-saving LCD screen of the electronic bus stop sign, the common-cathode LED energy-saving lamps of the smart bus shelter, and the control module, eliminating the need for separate power supplies for the bus stop sign and the bus shelter. This integrated design not only reduces equipment procurement and installation costs but also simplifies subsequent management, making it highly suitable for large-scale application at urban road bus stops. 6. This invention features a simplified overall structure, highly versatile components, and controllable costs. It eliminates the complex combiner boxes, anti-reverse diode arrays, and expensive optimizers or micro-inverters found in traditional series systems. The multi-channel independent PWM controllers are mature and universally applicable components, and the photovoltaic panels utilize standard components with internal parallel connections requiring no special processes. The overall structure is simple, material costs are low, and production and assembly efficiency is high, enabling the system cost to be controlled at or even lower than that of traditional series solutions, resulting in outstanding economic benefits. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Example The present invention discloses an anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters, comprising multiple sets of photovoltaic power generation units, multiple independent PWM solar controllers, lithium iron phosphate batteries, control modules, dynamic backlight energy-saving LCD screens, and common cathode LED energy-saving lamps.

[0026] The output of each power generation unit is connected to the input of an independent PWM solar controller. The outputs of the PWM solar controllers are connected in parallel and then connected to the charging input of the lithium iron phosphate battery. The discharging output of the lithium iron phosphate battery is connected to the power input of the control module. The control module is electrically connected to the dynamic backlight energy-saving LCD screen and the common cathode LED energy-saving lamp, respectively, to provide them with working power and send control signals.

[0027] In this embodiment, the solar photovoltaic panels use standard monocrystalline silicon or polycrystalline silicon photovoltaic modules, with a single panel power ranging from 50W to 200W. The number N of the multiple photovoltaic power generation unit groups is determined based on the usable area of ​​the bus shelter roof and the load power consumption requirements, typically ranging from 2 to 8 groups.

[0028] Taking a typical power generation unit as an example (such as the first power generation unit group 1-1), it consists of three independent parallel solar photovoltaic panels connected in a "positive to positive, negative to negative" manner, forming a low-voltage, high-current parallel unit. The electrical parameters (such as nominal voltage and maximum power point voltage) of each photovoltaic panel within the same group must be nominally consistent to avoid internal circulating current. There are no series connections between the power generation units; they are electrically completely independent.

[0029] Preferably, the number of photovoltaic panels connected in parallel within each power generation unit is 2 to 6. If there are fewer than 2 panels, the redundancy advantage of parallel grouping is lost; if there are more than 6 panels, the collector current is too large, increasing the requirements for cables and controllers, and reducing economic efficiency. In this embodiment, 3 panels are used per group, for a total of 4 groups, and the total number of photovoltaic panels is 12.

[0030] Each PWM solar controller 2 is an independently packaged circuit module, integrating a PWM charging management chip, power MOSFET, reverse charging protection diode, current sampling resistor, and overcharge protection circuit. There is no electrical connection between the controllers; their inputs are connected only to their corresponding set of power generation units, and their outputs are connected in parallel to a bus.

[0031] Each PWM controller independently performs voltage regulation, current limiting, and charging management functions. When the output voltage of a corresponding power generation unit drops due to shading or pollution, the controller for that unit automatically reduces the charging current, so that the unit operates near its maximum power point under the current lighting conditions; while the other controllers are unaffected and continue to charge according to the power generation capacity of their respective units.

[0032] When a single controller fails (such as MOSFET breakdown or open circuit), the faulty circuit is isolated by the internal protection circuit, and the other controllers continue to work normally. The overall charging power of the system is only lost on the faulty circuit, and the entire system will not be shut down.

[0033] The energy storage module uses a lithium iron phosphate battery pack 3 with a nominal voltage of 12.8V or 24V. The capacity is determined based on the daily power consumption of the load and the expected number of days of continuous operation on cloudy or rainy days. In this embodiment, a 12.8V / 100Ah lithium iron phosphate battery pack is selected.

[0034] The battery pack integrates a battery management system (BMS), which has at least the following protection functions: Overcharge protection function: charging is cut off when the voltage of a single battery cell reaches 3.65V; Over-discharge protection function: cuts off discharge when the voltage of a single battery cell drops below 2.5V; Overcurrent protection function: when the charging / discharging current exceeds a set threshold (e.g., 50A), the circuit breaker is delayed and cut off. Short-circuit protection function: instantly cuts off the output when a load short circuit is detected; Temperature protection function: charging and discharging are restricted when the battery temperature is below -20℃ or above 60℃.

[0035] The BMS also has a passive balancing function, which can balance the discharge of individual cells with high voltage during charging, thus extending the overall lifespan of the battery pack.

[0036] All solar photovoltaic panels are directly fixed to the roof of the bus shelter using a high-low support system. The high-low support system includes a front support and a rear support, with the front support being lower than the rear support, so that the photovoltaic panels are tilted towards the sun after installation.

[0037] In this embodiment, the tilt angle is set to 30°, which is suitable for mid-latitude regions in the Northern Hemisphere. Depending on the latitude of the installation location, this angle can be adjusted within the range of 15° to 45°. The bracket is made of hot-dip galvanized steel or aluminum alloy profiles, with a corrosion-resistant coating (such as powder coating or hot-dip galvanizing) on ​​the surface, with a thickness of not less than 50μm.

[0038] The base of the support frame is fixedly connected to the load-bearing steel beams of the bus shelter roof using stainless steel expansion bolts or welding. The top of the support frame is equipped with photovoltaic panel mounting slots or clamps, and the photovoltaic panel frames are fixed to the support frame using stainless steel bolt assemblies. This installation method eliminates the need for an additional ground-based photovoltaic support foundation, has a short construction period, and its wind-receiving area is calculated to be reasonable, capable of withstanding winds up to level 12.

[0039] Each power generation unit and its corresponding PWM controller, as well as the output terminals of each PWM controller and the input terminals of the lithium iron phosphate battery, are connected using independently laid 2×4 mm² copper core cables (i.e., two 4 mm² copper wires, one for positive and one for negative). The cables are photovoltaic-grade UV-resistant sheathed cables with a rated voltage of not less than DC 100V and a temperature range of -40℃ to 90℃.

[0040] The specific wiring method is as follows: Cables are led out from the positive and negative terminals of each power generation unit and independently laid along the metal cable trays inside the roof of the bus shelter to the corresponding PWM controller. The cable trays in each group are not interconnected. The controller output is also connected to the battery terminal block via independent 2×4 cables through the cable trays. The length of each cable group does not exceed 15 meters to ensure that the voltage drop is less than 3%.

[0041] The advantage of group cabling is that when a cable has insulation damage or a loose connection, that cable can be disconnected for repair or replacement without cutting off the power supply to other groups. This makes maintenance safe, convenient, and cost-effective.

[0042] The dynamic backlit energy-saving LCD screen is installed inside the electronic bus stop sign to display bus routes, arrival information, and announcements. The screen uses an LED-backlit LCD panel, and the backlight drive circuit supports PWM dimming.

[0043] The control module includes: an ambient light sensor (such as a BH1750 light intensity sensor), a battery power detection circuit (through resistor voltage division and ADC acquisition), an MCU processor (such as an STM32 series), and a communication interface (RS485 or CAN). The MCU has a pre-set backlight control algorithm.

[0044] The specific control logic is as follows: The MCU collects ambient illuminance values ​​(Lux) in real time via an ambient light sensor; The current SOC (%) of the lithium iron phosphate battery is obtained through the battery power detection circuit, and the current total power generation is read through communication with the PWM controller. The MCU dynamically adjusts the PWM duty cycle D_backlight of the LCD backlight according to the following rules: If Lux > 5000 (strong daylight) and SOC > 30%, then D_backlight = 100%; If Lux is between 500 and 5000, and the current total power generation is greater than the load power consumption, then D_backlight = 70%; If Lux < 500 (nighttime or dark environment), then D_backlight = 30%; If SOC < 20%, then D_backlight will be forcibly limited to below 50%, regardless of ambient lighting conditions.

[0045] The MCU controls the backlight drive circuit through the PWM output pin to achieve stepless brightness adjustment.

[0046] This dynamic backlight control can save 30% to 50% of display power consumption compared to conventional bright backlight solutions while ensuring visibility.

[0047] Common cathode LED energy-saving tubes are installed on the edge of the ceiling or in the seating area of ​​smart bus shelters for nighttime lighting and ambient illumination. These tubes employ a common cathode driving architecture, where the cathodes of all LED beads are connected to the negative terminal of the power supply (GND), while the anodes are independently controlled by constant current driving chips. Compared to the traditional common anode architecture, the common cathode approach reduces voltage drop losses in the driving circuit, resulting in an overall luminous efficiency improvement of approximately 15%.

[0048] The control module further includes an ambient light intensity sensor (which can be shared with the screen or independent) and a real-time clock RTC. The control module implements four-level brightness control according to the ambient illuminance and battery power.

[0049] Meanwhile, the control module monitors the state of charge (SOC) of the battery in real time: When SOC > 50%, it is executed normally according to the above illuminance levels; When 30% < SOC ≤ 50%, level 2 (fully bright at night) is forced to be reduced to half bright (50%); When SOC ≤ 30%, all levels are forced to be reduced to the lowest brightness (20%). If SOC is further lower than 15%, all亮化灯管 will be turned off, and only the electronic bus stop display will be maintained.

[0050] The control module also supports manual or remote setting of the亮化时段. For example, it can be set that the灯管 is only allowed to be turned on between 18:00 and 6:00 the next day, to avoid waste caused by accidental lighting during the day.

[0051] Combined with the actual occlusion scenario, the anti-occlusion working process of this system is described in detail.

[0052] When a total of 4 sets of power generation units (each set has 3 parallel photovoltaic panels) are installed on the shed roof of the bus stop, corresponding to 4 independent PWM controllers respectively. One afternoon, one photovoltaic panel in the second set of power generation units was obliquely occluded by the shadow of an adjacent building, and the output current of this photovoltaic panel dropped from 5A to 1.5A. Since the internal structure of this set is in parallel, the other two unoccluded photovoltaic panels still output normal current (5A each). Therefore, the total output current of the second set of power generation units is 1.5A + 5A + 5A = 11.5A, and the voltage remains at the normal value (about 18V).

[0053] The second PWM controller detected a decrease in the input current and automatically reduced the charging current to 11.5A (i.e., still charging at the maximum available power). At the same time, the first, third, and fourth sets of power generation units were not affected at all and output 15A, 14A, and 15A respectively. The total charging current of the system is 11.5 + 15 + 14 + 15 = 55.5A, which is only 7.5% lower than the theoretical total current (60A) without occlusion, far from reaching the degree of power supply interruption.

[0054] If a traditional series structure (all 12 photovoltaic panels are in series) is used, then occluding one panel by the shadow will cause the current of the whole string to drop to 1.5A, and the total power will drop by more than 70% instantly. The electronic bus stop and亮化灯管 will face the risk of power supply interruption.

[0055] The control method of this system includes the following steps: S1: Divide all photovoltaic panels into N groups of independent parallel power generation units, and connect the positive poles to each other and the negative poles to each other inside each group; S2: Connect N sets of power generation units to N electrically independent PWM solar controllers; S3: Connect the outputs of the N-channel PWM controllers in parallel to the charging input of the lithium iron phosphate battery. S4: The lithium iron phosphate battery, through the control module, supplies power to the dynamic backlight energy-saving LCD screen and the common cathode LED energy-saving lamp; S5: When any photovoltaic panel is partially shaded or its surface is contaminated, the output power of the power generation unit where the photovoltaic panel is located decreases. The PWM controller corresponding to the unit independently reduces its charging current, while the other N-1 controllers maintain their original charging state, and the overall power supply of the system is not interrupted.

[0056] Furthermore, this system also performs low-power load linkage control steps: S6: The control module collects ambient illuminance, battery SOC, and current total power generation in real time; S7: When the current total power generation is lower than the first threshold (e.g., 1.2 times the total power consumption of the load) and the SOC is lower than the second threshold (e.g., 30%), the control module first reduces the backlight brightness of the dynamic backlight energy-saving LCD screen by one level; if the power supply is still unbalanced after 5 minutes, the brightness level of the common cathode LED tube is gradually reduced (from full brightness to half brightness, and then to 20% brightness). S8: When the current total power generation recovers to above the third threshold (e.g., 1.5 times the total power consumption of the load) and the SOC rises to above the fourth threshold (e.g., 50%), the control module gradually restores the brightness of the lamps and the backlight of the screen to normal.

[0057] In a preferred embodiment, the control module further integrates a wireless communication unit, such as a 4G Cat.1 module or an NB-IoT module. This communication unit periodically uploads system operating status parameters remotely to a cloud monitoring platform. These operating status parameters include: Real-time voltage, current, and power generation of each power generation unit; Voltage, current, SOC, and temperature of lithium iron phosphate batteries; Current backlight brightness and power consumption of the dynamic backlit LCD screen; Current brightness level and power consumption of common cathode LED tubes; Operating status of each PWM controller (normal / fault / current limiting).

[0058] The monitoring platform can issue alarms for abnormal conditions (such as a long-term low power output of a certain circuit, indicating photovoltaic panel pollution or malfunction; or excessively high battery temperature, indicating poor heat dissipation), and can remotely issue control commands (such as forcibly reducing the brightness of the lighting, restarting the controller, etc.) to achieve unattended intelligent operation and maintenance.

[0059] This specific embodiment details the structural composition, installation method, circuit connection, control logic, and workflow of the anti-shading solar power supply system of the present invention. By adopting a technical solution of "group independent parallel power generation + multi-channel independent PWM control + lithium iron phosphate energy storage + dynamic backlight LCD + common cathode LED energy-saving lamps," and in conjunction with high and low bracket installation and group cable wiring, it effectively solves the long-standing technical problems of low power generation efficiency, unreliable power supply, and high installation and maintenance costs in traditional series structures under outdoor shading and pollution environments, demonstrating significant technological advancement and practical value.

[0060] The above description is merely a preferred embodiment of the present invention and is not intended to further limit the present invention. All equivalent changes made based on the content of this specification are within the protection scope of the present invention.

Claims

1. An anti-shading solar power supply system for outdoor electronic bus stop signs and shelters, comprising: Multiple photovoltaic power generation units, each consisting of at least two solar photovoltaic panels connected independently in parallel with positive terminals connected to positive terminals and negative terminals connected to negative terminals, and no series connection between the power generation units; Multiple independent PWM solar controllers, each PWM controller's input terminal is electrically connected to only one set of power generation units, and each PWM controller is electrically independent of the others; The input terminal of the lithium iron phosphate battery energy storage module is connected in parallel with the output terminal of the multi-channel independent PWM controller. The control module is powered by the lithium iron phosphate battery; A dynamic backlit energy-saving LCD screen is installed inside the electronic bus stop sign and is controlled by a control module. Common cathode LED energy-saving tubes are installed in the smart bus shelter and controlled by the control module; The feature is that the outputs of the multiple independent PWM controllers are connected in parallel and then combined to charge the lithium iron phosphate battery; the lithium iron phosphate battery, through the control module, supplies power to the dynamic backlight energy-saving LCD screen and the common cathode LED energy-saving lamp respectively; When any solar photovoltaic panel is partially blocked by an external obstruction or its surface is covered by pollutants, only the output power of the power generation unit to which that photovoltaic panel belongs decreases, while the other power generation units continue to generate power independently and normally, and the overall output power of the system remains uninterrupted.

2. The anti-shading solar power supply system for outdoor electronic bus stop signs and shelters according to claim 1, characterized in that: Each of the multiple photovoltaic power generation units has 2 to 6 photovoltaic panels connected in parallel, and the electrical parameters of each photovoltaic panel in the same group are consistent. Each power generation unit and its corresponding PWM controller, as well as the output terminals of each PWM controller and the lithium iron phosphate battery, are connected by independently laid DC power cables. Each cable is a 2×4 square millimeter copper core cable. Each group of cables is laid independently along the inner side of the roof of the bus shelter or in the cable tray, and they are not connected to each other.

3. The anti-shading solar power supply system for outdoor electronic bus stop signs and shelters according to claim 1, characterized in that: Each of the multi-channel independent PWM solar controllers integrates an independent MPPT or PWM charging management circuit, and has functions such as voltage regulation, current limiting, reverse charging protection, and overcharge protection. There is no electrical series connection between the controllers. When a single controller fails or the corresponding power generation unit is abnormal, the other controllers continue to work normally.

4. The anti-shading solar power supply system for outdoor electronic bus stop signs and shelters according to claim 1, characterized in that: The lithium iron phosphate battery energy storage module integrates a battery management system (BMS) circuit, which has at least overcharge protection, over-discharge protection, overcurrent protection, short circuit protection, and battery temperature monitoring functions.

5. The anti-shading solar power supply system for outdoor electronic bus stop signs and shelters according to claim 1, characterized in that: The solar photovoltaic panels are directly fixed to the roof of the bus shelter using a high-low bracket system. The front end of the high-low bracket system is lower than the rear end, so that the photovoltaic panels are tilted towards the sun. The bottom of the bracket system is fixedly connected to the roof of the bus shelter using bolts or welding. The inclination angle of the high and low supports is 15° to 45°. The supports are made of galvanized steel or aluminum alloy profiles and have an anti-corrosion coating on their surface.

6. The anti-shading solar power supply system for outdoor electronic bus stop signs and shelters according to claim 1, characterized in that: The dynamic backlight energy-saving LCD screen has a built-in backlight driving circuit, and the control module includes an ambient light sensor, a battery power detection circuit, and an MCU processor. The MCU processor dynamically adjusts the backlight PWM duty cycle of the LCD screen based on the ambient illuminance value collected by the ambient light sensor, the current power of the lithium iron phosphate battery collected by the battery power detection circuit, and the current power generation obtained through the communication interface, so as to achieve adaptive energy-saving control of the backlight brightness.

7. The anti-shading solar power supply system for outdoor electronic bus stop signs and shelters according to claim 1, characterized in that: The common cathode LED energy-saving lamp tube adopts a common cathode driving architecture, that is, the cathodes of all LED beads are connected to the negative terminal of the power supply, and the anodes are independently controlled by constant current driving chips. The control module includes an ambient light illuminance sensor and a battery power detection circuit. According to the illuminance value collected by the ambient light illuminance sensor, the control module divides the working state of the lamp tube into four levels: fully off during the day, low brightness at dusk, full brightness at night, and half brightness at night. At the same time, when the battery power is lower than the preset threshold, the control module forces the lamp tube to switch to a lower brightness level.

8. A power supply control method for an anti-shading solar power supply system for outdoor electronic bus stop signs and waiting shelters based on any one of claims 1 to 7, characterized in that: Includes the following steps: Step S1: Divide all solar photovoltaic panels into N independent parallel power generation units, with positive photovoltaic panels connected positively and negative photovoltaic panels connected negatively within each unit; Step S2: Connect the N groups of power generation units to N electrically independent PWM solar controllers respectively; Step S3: Connect the output terminals of the N-channel PWM controllers in parallel to the charging input terminal of the lithium iron phosphate battery; Step S4: The lithium iron phosphate battery supplies power to the dynamic backlight energy-saving LCD screen and the common cathode LED energy-saving lamp tube respectively via the control module; Step S5: When any photovoltaic panel is partially shaded or its surface is contaminated, the output power of the power generation unit where the photovoltaic panel is located decreases, but the PWM controller corresponding to this unit independently reduces its charging current, while the other N-1 controllers maintain their original charging state, and the overall power supply of the system is not interrupted. Step S6: The control module collects ambient illuminance, battery power, and current total power generation in real time; Step S7: When the total power generation is lower than the first threshold and the battery power is lower than the second threshold, the control module first reduces the backlight brightness of the dynamic backlight energy-saving LCD screen. If the power supply balance is still not met, the brightness level of the common cathode LED energy-saving lamp tube is reduced step by step. Step S8: When the total power generation recovers to above the third threshold and the battery power recovers to above the fourth threshold, the control module gradually restores the brightness of the lamps and the backlight of the screen.

9. The anti-shading solar power supply system for outdoor electronic bus stop signs and shelters according to claim 1, characterized in that: The control module also integrates a wireless communication unit for remotely uploading system operating status parameters to the monitoring platform. These operating status parameters include: real-time power generation of each power generation unit, battery power, load power consumption, and the operating status of each PWM controller.