Illumination intensity self-adaptive tunnel illumination photovoltaic power supply system and implementation method

Abstract

The invention discloses an illumination intensity self-adaptive tunnel illumination photovoltaic power supply system and an implementation method, and the system comprises a photovoltaic power generation panel which outputs a DC voltage to supply power to tunnel LED lamps, the illumination of each LED lamp is adjusted through a respective LED light modulator, the LED light modulators are connected with a PLC through a 3 # bus unit CAN3, the PLC transmits an illumination adjustment signal to the LED light modulators through the 3 # bus unit CAN3, and the LED light modulators are connected with the photovoltaic power generation panel. The output power can be adjusted from 0% to 100%, so that the illumination of the LED lamp is changed from 0% to 100%; an illuminometer is mounted outside the tunnel to detect the ambient illuminance outside the tunnel; a plurality of illuminometers are installed in each illumination area in the tunnel, and the actual illuminance of each area can be detected; all the illuminometers are connected with the PLC through the 1 # bus unit CAN1, data of each illuminometer is transmitted to the PLC in real time through the 1 # bus unit CAN1, the characteristics of photovoltaic power generation and tunnel illumination are combined, the illumination intensity outside a tunnel is detected, the illuminance of lamps in all areas in the tunnel is dynamically adjusted, and the illumination of all the areas is switched on and off according to the traffic flow and the vehicle position.

Description

Technical Field

[0001] The present invention is a photovoltaic power supply system for tunnel lighting with self - adapting light intensity and an implementation method thereof, belonging to the technical field of power supply systems. Background Art

[0002] The main energy consumption of expressways is not in service areas and toll stations. 70% - 80% of the energy consumption is for tunnel lighting. Traditional tunnel lighting systems mostly rely on mains power supply, having problems such as high energy consumption and large operation costs.

[0003] The characteristics of tunnel lighting are that it should not be too bright at night, and the better the sun is during the day, the higher the illuminance required inside the tunnel, and the greater the energy consumption. It is estimated that the daytime lighting energy consumption of tunnels accounts for more than 80% of the total tunnel lighting and about 60% of the total expressway energy consumption. And during the day is the peak period of photovoltaic power generation. Using photovoltaic power generation for tunnel lighting has huge economic and social benefits.

[0004] The requirement for the illuminance distribution of tunnel lighting is that in the case of strong daylight, the illuminance of the lamps at the entrance is the same as the brightness outside the tunnel, avoiding sudden darkness in the environment and causing drivers to have a stress response and emergency braking; as the tunnel goes deeper, the brightness gradually decreases to the darkest in the middle of the tunnel, and then the illuminance gradually increases until the exit; at night, the darkness at the entrance is the same as the darkness outside the tunnel, avoiding glare for drivers due to the high brightness of the lamps. As the tunnel goes deeper, the brightness gradually increases to the middle of the tunnel, and then the illuminance gradually decreases until the exit.

[0005] How to maximize energy conservation, emission reduction and economic benefits while ensuring the tunnel lighting effect and safe driving is the main challenge faced by the current tunnel lighting system.

[0006] In the existing tunnel lighting technology with photovoltaic power supply, the light intensity of a single lamp cannot be adjusted. Specific lamp units are turned on or off manually or through a timer, and the overall brightness is adjusted by changing the number of lighting lamps. For example, only auxiliary lighting lamps are turned on at night, and enhanced lighting lamps are turned on during the day based on the auxiliary lighting.

[0007] The existing tunnel lighting technology with photovoltaic power supply has a low degree of automation, non - linear adjustment of illuminance, and cannot accurately match the illuminance inside and outside the tunnel. The difference in light between inside and outside the tunnel is large, resulting in glare and visual fatigue, affecting safe driving; when there is no traffic flow, the tunnel lighting remains on, which is ineffective lighting, shortening the lamp life and wasting energy.

[0008] In the prior art, to solve the above problems, a linear lighting curve is adopted to control the LED lights in the tunnel, and different illuminance adjustments are made to the LED lights in the tunnel from the entrance to the exit. However, due to the possible existence of natural light, vehicle lights or other stray lights in the tunnel, the aging of the lights, the inaccurate installation position of the illuminance meter, etc., these will all affect the true measurement of the LED illuminance. At the same time, in the face of emergencies (such as sudden drops in external light caused by heavy rain or thick fog), the adjustment speed of the LED illuminance in the prior art is too slow, which will result in inaccurate lighting control in the tunnel. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a tunnel lighting photovoltaic power supply system with self-adaptive light intensity and its implementation method in view of the above deficiencies. Combining the characteristics of photovoltaic power generation and tunnel lighting, it detects the light intensity outside the tunnel, dynamically adjusts the illuminance of the lamps in each area inside the tunnel, and switches on and off the lighting in each area according to the traffic flow and vehicle position, calibrates the actual illuminance of each lighting area inside the tunnel, eliminates the illuminance error caused by lamp aging and dust occlusion, eliminates the error caused by the deviation between the internal illuminance meter and the external illuminance meter, and realizes precise adjustment and control of the lighting in each area inside the tunnel.

[0010] To solve the above technical problems, the present invention adopts the following technical solutions: A tunnel lighting photovoltaic power supply system with self-adaptive light intensity includes a photovoltaic power generation panel. The photovoltaic power generation panel is installed on the highway slope near the tunnel. The positive and negative poles of the photovoltaic power generation panel output a power supply L1 line and an N1 line. The power supply L1 line and the N1 line are connected to a PLC. The PLC is connected to a 1# bus unit CAN1, a 2# bus unit CAN2, and a 3# bus unit CAN3. From the tunnel entrance to the exit, N different lighting areas are divided. A position sensor is installed at the front end of each lighting area. An LED lamp and an illuminance meter are installed at the middle position of each lighting area. The 1# bus unit CAN1 is connected to N internal illuminance meters and external illuminance meters. The data of each internal illuminance meter is transmitted to the PLC in real time through the bus. The external illuminance meter is installed outside the tunnel and is used to detect the environmental illuminance outside the tunnel. An internal illuminance meter is installed in each lighting area inside the tunnel. The N internal illuminance meters can detect the actual illuminance of each lighting area. The 2# bus unit CAN2 is connected to an entrance radar and N position sensors. The position sensors are installed in each lighting area inside the tunnel. When a vehicle triggers a position sensor, it enters the lighting area. When a vehicle triggers the next position sensor, it leaves the previous lighting area. The 3# bus unit CAN3 is connected to N LED dimmers. The LED dimmers use PWM regulation to realize the dimming of the LED lamps. Each LED dimmer is connected to an LED lamp. The PLC transmits an illuminance adjustment signal to the LED dimmers through the 3# bus unit CAN3 bus, and can adjust the output power from 0% - 100%, so that the illuminance of the LED lamps changes from 0% - 100%.

[0011] Further, the power supply L1 line and N1 line are also connected to an inverter and a rectifier, and are connected to the national power grid through the inverter and the rectifier. The power supply L1 line and N1 line are connected to a reference voltage generator, the reference voltage generator is connected to a 1# voltage comparator and a 2# voltage comparator, one end of the 1# relay coil is connected to the 1# voltage comparator, the other end of the 1# relay coil is grounded, one end of the 2# relay coil is connected to the 2# voltage comparator, and the other end of the 2# relay coil is grounded; the power supply L1 line and N1 line are also connected to a charge and discharge management module, and the charge and discharge management module is connected to a battery pack.

[0012] A method for realizing a tunnel lighting photovoltaic power supply system with self - adaptive light intensity includes the following steps: Step 1: The PLC generates an illuminance curve for each lighting area in the tunnel according to the externally received illuminometer value. Step 2: Calibrate the actual illuminance of each lighting area in the tunnel to eliminate the illuminance error caused by lamp aging and dust occlusion, and eliminate the error caused by the deviation between the internal illuminometer and the external illuminometer. Step 3: The PLC controls the LED lamps in each lighting area according to the illuminance curve. Step 4: Abnormal handling mechanism; Illuminometer failure: If the data in a certain area exceeds the limit or remains unchanged, the average value of adjacent areas is used for substitution. Communication interruption: The 1# bus unit CAN1, 2# bus unit CAN2 and 3# bus unit CAN3 are redundantly designed, and the last valid illuminance curve is maintained after timeout. Extreme weather: When the external illuminance drops suddenly, immediately switch to the highest lighting level. Step 5: Control the photovoltaic power generation of the photovoltaic panel. When there is surplus photovoltaic power generation, on the premise of ensuring the electricity consumption of the tunnel, the photovoltaic power generation feeds back to the national power grid; when there is a shortage of photovoltaic power generation, the national power grid supplements the shortage part of the photovoltaic power generation to ensure the electricity consumption of the tunnel. The input terminals of the reference voltage generator are connected in parallel to the power output terminal of the photovoltaic panel. The output terminal of the reference voltage generator outputs two standard voltages U1 and U2. The standard voltage U1 is the threshold voltage for upward grid - connected power generation, and the standard voltage U2 is the threshold voltage for downward power consumption. The output voltage of the photovoltaic panel, through the charge and discharge management module, charges the battery. When the weather is sunny and the sunlight is sufficient, the output voltage of the photovoltaic panel is relatively high, and the battery charges quickly. When the battery is full and the traffic flow in the tunnel is small, the output voltage of the photovoltaic panel rises to reach the upward grid - connected power generation threshold voltage U1. The output terminal of the 1# voltage comparator is at a high level, the 1# relay coil is energized and attracted, the 1# relay contact is closed, and the photovoltaic power generation is connected to the grid for upward power generation through the inverter. When the light is insufficient and the photovoltaic power generation is small, the battery is insufficiently charged, the output voltage of the photovoltaic panel is pulled down by the battery, and the output voltage of the photovoltaic panel drops to reach the downward power consumption threshold voltage U2. The output terminal of the 2# voltage comparator is at a high level, the coil of the 2# relay is energized and attracted, the contacts of the 2# relay are closed, and the state grid supplements the photovoltaic power through the rectifier and voltage regulator; In the case of sufficient sunlight and continuous tunnel traffic, the photovoltaic power generation is designed to just meet the tunnel power consumption demand. The photovoltaic system does not need to connect to the state grid for upward power generation and downward power consumption through relays. Suppose the output voltage U0 of the photovoltaic panel at this time is 95V, and there is U1 < U0 < U2.

[0013] Further, the first step includes the following steps: Step 1, data collection and preprocessing; Step 2, dynamically segment the tunnel and allocate illuminance to each segment; Step 3, generate an illuminance curve from the spatial dimension. For the entire tunnel, with time as the horizontal axis and the illuminance of each lighting area as the vertical axis, generate a two-dimensional spatio-temporal illuminance surface. Divide 24 hours into 1440 time points in minutes, that is, t = 1, 2,..., 1440, and allocate the target illuminance to the lighting areas at each time point. The calculation formula is , where Lj(t) is the target illuminance of the lighting area j at the time point t, Eout(t) is the external illuminance collected at the time point t, dj is the distance of the lighting area j from the tunnel entrance, and η is the attenuation coefficient; Step 4, generate an illuminance curve from the time dimension. Considering day and night and weather changes, generate a 24-hour illuminance curve. Connect the target illuminances within 24 hours in each lighting area in chronological order to form the time-illuminance curve of the lighting area. During the day, dynamically adjust the illuminance of each lighting area according to Step 2, and fix the basic lighting at night; Step 5, perform smooth transition processing on the illuminance values of each lighting area to avoid frequent jumps, set a limit on the illuminance difference between adjacent lighting areas, and use first-order lag filtering. The calculation formula is , where is the smoothing factor, , where is the actual illuminance value of the lighting area j at the time point t, is the target illuminance value of the lighting area j at the time point t.

[0014] Further, the data collection and preprocessing include the following steps: Read the internal illuminance Ein of the tunnel, read the internal illuminance meters of each lighting area, and mark the corresponding area numbers j = 1, 2,..., N; The external illuminance Eout of the tunnel. The PLC periodically reads the data of the external illuminometer through the 1# bus unit CAN1, and smooths the collected external illuminance values to eliminate the instantaneous fluctuations in the data, improving the stability and reliability of the tunnel lighting system. The specific process is as follows: Step 1.1: Use the arithmetic mean of the illuminance values of the past N sampling points as the current output value to weaken random fluctuations: ; where Yn is the output value after filtering the data of the external illuminometer; Xn-i is the original illuminance value data of the nth sampling; N is the size of the sliding window; Step 1.2: Set the size N of the sliding window in the PLC. N is selected to be 3 - 6. That is, when the sampling period is 1 time per minute, it covers the data of 3 - 6 minutes. An array with a length of N is opened in the PLC to store historical data, and the pointer circularly overwrites the old data. When each new data arrives, subtract the oldest data, remove the earliest data from the cumulative sum, store the new data and update the cumulative sum; Step 1.3: Optimize the variant to reduce the lag of the illuminance value and improve the smoothness, thus providing a faster response speed and a more accurate signal. The specific calculation formula is as follows: ; where ;.

[0015] Step 1.4: Online monitor the filtering effect, record the data before and after filtering in the PLC, and regularly analyze the residuals to ensure no systematic deviation.

[0016] Furthermore, the specific process of dynamically segmenting the tunnel and allocating illuminance to each segment is as follows: The tunnel is divided into several logical segments, including the entrance segment, the transition segment, the middle segment, and the exit segment. Each segment includes several lighting areas, and the target illuminance values of each segment are dynamically adjusted; The illuminance requirements of the entrance segment, the transition segment, the middle segment, and the exit segment of the tunnel are different: The entrance segment requires the highest illuminance, , where kin is the proportionality coefficient, with a value of 0.1 - 0.3, and Emin is the lowest international standard threshold; The illuminance of the transition segment needs to achieve a smooth transition from the high brightness of the entrance segment to the low brightness of the middle segment, avoiding visual abrupt changes. When allocating illuminance, the brightness decreases in a gradient, and it is divided into 1 - 3 sub - segments. The brightness of each segment decreases to 1 / 3 - 1 / 2 of the brightness of the previous segment. The calculation formula is: , Ln is the brightness of the current sub - segment, Ln - 1 is the brightness of the previous sub - segment, and β is the brightness attenuation coefficient, taking 1 / 3 - 1 / 2; The illuminance of the middle segment is a fixed low illuminance, and the calculation formula is where Q is the traffic flow coefficient, L is the tunnel length, and it is necessary to ensure that Lm is not lower than Emin; The illuminance distribution in the exit section needs to be slightly higher than that in the middle section. The calculation formula is where kout is the exit section proportionality coefficient, with a value range of 1.5 - 5.

[0017] Furthermore, the second step includes the following steps: Step 6, reference calibration, with a frequency of once a month or after system maintenance, to eliminate ambient light interference and determine the basic hardware parameters; Step 7, linearity calibration, with a frequency of once a quarter or after replacing the lamps, to solve the non - linear response problem of LED lamps; Gradient test: Control the LED lamps to operate at 10%, 30%, 50%, 70%, 90%, and 100% power. After continuously operating for 1 minute at each PWM power control point, record the values of the internal illuminance meters in each lighting area, excluding transient effects. Measure each power 3 times and take the average to obtain a data set: {(PWM1, L1), (PWM2, L2), ……, (PWMn, Ln)}; Curve fitting: Establish a PWM - illuminance relationship model. The formula for illuminance is where a, b, and c are storage coefficients, calculated using the built - in fitting function of the PLC. The system can eliminate non - linear errors, improve the illuminance control accuracy to within ±3%, and achieve fast and accurate dimming; Step 8, dynamic feedback calibration, continuously running to correct short - term fluctuations and long - term aging errors in real - time.

[0018] Furthermore, the step 6 includes the following steps: Step 6.1, turn off all the LED lamps in the tunnel, read the data of the internal illuminance meters in each lighting area, and use it as the ambient background illuminance value Loffset; The ambient background illuminance value Loffset can eliminate ambient light interference. The actual contributed illuminance of the LED lamps is the measured illuminance of the illuminance meter minus the ambient background illuminance value Loffset; The illuminance meter has a small output in a light - free environment. The ambient background illuminance value Loffset is used to correct the small deviation of the illuminance meter, correct the zero - point drift of the illuminance meter, so that under different times or weather conditions, the calibrated illuminance data has consistency and ensures the comparability of the data; Step 6.2: Light up the LED lamps in each lighting area at full power. After the LED lamps operate stably at 100% PWM, record the maximum illuminance value Lmaxj of each area. Subtract the local illuminance value L1 to obtain the actual maximum illuminance value of the LED lamps. Compare the actual maximum illuminance value with the allocated target illuminance value, and it is required to meet the condition that the actual maximum illuminance value ≥ target illuminance value - tolerance. The tolerance is ±5% - 10% of the target illuminance value. If the standard is not met, find the reason and take corresponding measures.

[0019] Further, the said Step 8 includes the following steps: Step 8.1: Collect actual illuminance data in real time. The PLC reads the actual illuminance values detected by the internal illuminance meters in each lighting area in real time through the 1# CAN bus unit, compares them with the theoretical illuminance values of the corresponding lighting areas determined according to the generated illuminance curve, and calculates the deviation ΔL between the actual illuminance value and the theoretical illuminance value. Step 8.2: Determine whether the deviation ΔL exceeds the preset threshold. A preset allowable deviation threshold of 5% of the theoretical illuminance is set in the PLC. If the deviation ΔL exceeds the threshold, it is considered that the illuminance of this area needs to be adjusted. Step 8.3: Adjust the illuminance of the LED lamps. For the lighting areas where the deviation exceeds the threshold, the PLC calculates the adjustment amount of the LED lamps according to the deviation magnitude. The PLC dynamically adjusts the PWM output through the PID algorithm. The calculation formula is as follows: ; where Kp is the proportionality coefficient, used to quickly respond to the current deviation, Ki is the integral coefficient, used to eliminate the steady-state error, Kd is the differential coefficient, used to suppress overshoot. Kp, Ki, and Kd are determined through experiments.

[0020] Further, in the said Step 3, the PLC controls the LED lamps in each lighting area according to the illuminance curve. The specific process is as follows: Send out the illuminance adjustment signal of each area through the 3# bus unit CAN3; each area's LED dimmer corresponds to a station number j = 1, 2, ……, N. The LED dimmers in each area receive the illuminance adjustment signal according to the station number and adjust the power of the LED lamps in their respective areas; the illuminance meter in this area detects the illuminance in real time, sends the actual illuminance value, and sends it to the PLC through the 1# bus unit CAN1. The PLC judges whether the illuminance of each area meets the requirements according to the station number of this area. For those with illuminance deviation, send the adjusted illuminance signal again through the 3# bus unit to make the illuminance of each area meet the requirements of the illuminance curve. Due to the different illuminances outside the tunnel, the illuminance curves of each area in the tunnel are also different. According to the requirements of tunnel lighting, the illuminance at the tunnel entrance should be the same as that outside the tunnel. As the distance deepens, in the daytime, the illuminance gradually decreases and then gradually increases at the exit; in the nighttime, the illuminance gradually increases and then gradually decreases at the exit. For driving safety and to avoid visual discomfort and fatigue caused by the illuminance to the driver, the illuminance curves of each area in the tunnel are pre-entered into the PLC according to industry standards. The PLC adjusts the power of the LED lamps according to the numerical feedback of each illuminometer to make the illuminance meet the requirements. To avoid the problem that the lamps in the tunnel are always on when there are no vehicles or the traffic flow is small, a radar is installed at a distance of S meters from the tunnel entrance. When a vehicle passes by, the vehicle speed is detected as V, and the estimated time for the vehicle to reach the tunnel is , and the LED lamps at the tunnel entrance are turned on 3 seconds before the vehicle enters the tunnel, and the illuminance of the lamps is the same as that outside the tunnel. When the vehicle reaches the tunnel entrance, position sensor 1 is triggered, and the sensor signal is transmitted to the PLC through the bus unit CAN2. The PLC turns on the lighting in area 2 according to the sensor station number. When the vehicle travels to area 2, position sensor 2 is triggered, and the sensor signal is transmitted to the PLC through the bus unit CAN2. The PLC turns on the lighting in area 3 according to the sensor station number and turns off the lighting in area 1 at the same time. In this way, in a cycle, before reaching the tunnel exit, the lighting in the area behind the vehicle is turned off, and the lighting in the area where the vehicle is located and the previous area, a total of two areas, remains on until the vehicle exits the tunnel and all the tunnel lighting is turned off. When the vehicle stays in a certain area due to a fault or other reasons, since the position sensor in the next area is not triggered, the lighting in this area remains on until the vehicle drives out. For the situation of a large traffic flow and multiple vehicles driving into one area, the PLC counts the number of trigger times of the position sensor. When the number of trigger times of the trigger in area N + 1 is equal to the number of trigger times of the trigger in area N, it means that all vehicles have driven out of area N, and the LED lamps in area N can be turned off.

[0021] The present invention adopts the above technical solutions. Compared with the prior art, it has the following technical effects: The present invention combines the characteristics of photovoltaic power generation and tunnel lighting, detects the light intensity outside the tunnel, dynamically adjusts the illuminance of the lamps in each area in the tunnel, and turns on and off the lighting in each area according to the traffic flow and vehicle position, calibrates the actual illuminance of each lighting area in the tunnel, eliminates the illuminance error caused by lamp aging and dust occlusion, and eliminates the error caused by the deviation between the internal illuminometer and the external illuminometer, realizing precise adjustment and control of the lighting in each area in the tunnel.

[0022] 1. Automatically adjust the illuminance of the tunnel lights according to the external illuminance of the tunnel to avoid sudden brightness changes and visual fatigue for drivers during tunnel driving, thus eliminating potential driving safety hazards.

[0023] 2. Monitor the vehicle position, turn on the lights when a vehicle passes, and turn off the lights when there is no vehicle, saving energy and extending the service life of the lights.

[0024] 3. After calibration, the system can handle emergencies (such as sudden drops in external illuminance caused by heavy rain or thick fog), dynamically adjust the LED output to maintain safe lighting, and avoid over-illumination (such as automatically reducing the PWM when the actual illuminance is higher than the demand), reducing energy waste.

[0025] 4. After calibration, the steady-state error ≤ ±3% of the target value, the LED lamp has a short adjustment response time, the step response from 50% of the target value to 100% ≤ 10 seconds, strong anti-interference ability, the transient disturbance recovery time ≤ 5 seconds, and the tunnel lighting system can achieve high-precision, adaptive and robust control, significantly improving safety and energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0027] Figure 1 It is a schematic structural diagram of a tunnel lighting photovoltaic power supply system with adaptive light intensity according to the present invention; Figure 2 It is a schematic diagram of the lighting area division in the tunnel according to the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Embodiment, as Figure 1 shown, a tunnel lighting photovoltaic power supply system with adaptive light intensity includes a photovoltaic power generation panel. The photovoltaic power generation panel is installed on the highway slope near the tunnel. The positive and negative poles of the photovoltaic power generation panel output a power supply L1 line and an N1 line. The power supply L1 line and the N1 line are connected to an inverter and a rectifier, and are connected to the national power grid through the inverter and the rectifier. The power supply L1 line and the N1 line are connected to a reference voltage generator. The reference voltage generator is connected to a 1# voltage comparator and a 2# voltage comparator. One end of the 1# relay coil is connected to the 1# voltage comparator, and the other end of the 1# relay coil is grounded. One end of the 2# relay coil is connected to the 2# voltage comparator, and the other end of the 2# relay coil is grounded; the power supply L1 line and the N1 line are also connected to a charge and discharge management module, and the charge and discharge management module is connected to a battery pack.

[0029] The power supply L1 line and N1 line are also connected to a PLC, and the PLC is connected to a 1# bus unit CAN1, a 2# bus unit CAN2, and a 3# bus unit CAN3. As Figure 2 shown, from the tunnel entrance to the exit, N different lighting areas are divided. A position sensor is installed at the front end of each lighting area, and an LED lamp and an illuminance meter are installed at the middle position of each lighting area. The 1# bus unit CAN1 is connected to N internal illuminance meters and an external illuminance meter. The data of each internal illuminance meter is transmitted to the PLC in real time through the bus. The external illuminance meter is installed outside the tunnel to detect the external environmental illuminance of the tunnel. An internal illuminance meter is installed in each lighting area inside the tunnel. The N internal illuminance meters can detect the actual illuminance of each lighting area. The 2# bus unit CAN2 is connected to an entrance radar and N position sensors. The position sensors are installed in each lighting area inside the tunnel. When a vehicle triggers a position sensor, it means entering that lighting area. When a vehicle triggers the next position sensor, it means leaving the previous lighting area. The 3# bus unit CAN3 is connected to N LED dimmers. The LED dimmers use PWM regulation to achieve dimming of the LED lamps. Each LED dimmer is connected to an LED lamp. The PLC transmits an illuminance adjustment signal to the LED dimmers through the 3# bus unit CAN3 bus, and can adjust the output power from 0% - 100%, so that the illuminance of the LED lamps changes from 0% - 100%.

[0030] A method for realizing a tunnel lighting photovoltaic power supply system with self - adapting light intensity includes the following steps: Step 1, the PLC generates an illuminance curve for each lighting area inside the tunnel according to the received value of the external illuminance meter. The specific process is as follows: Step 1, data collection and pre - processing; The internal illuminance E of the tunnel in , read the internal illuminance meters of each lighting area, and mark the corresponding area numbers j = 1, 2, ……, N.

[0031] The external illuminance E of the tunnel out , the PLC periodically reads the data of the external illuminance meter through the 1# bus unit CAN1 (such as once a minute), and performs smoothing processing on the collected external illuminance values to eliminate the instantaneous fluctuations in the data, and improve the stability and reliability of the tunnel lighting system. The specific process is as follows: Step 1.1, use the arithmetic mean of the illuminance values of the past N sampling points as the current output value to weaken the random fluctuations: ; Among them, Y n is the output value after filtering the data of the external illuminance meter; X n-i is the original illuminance value data of the nth sampling; N is the size of the sliding window.

[0032] Step 1.2, set the size N of the sliding window in the PLC. If N is too large, the smoothing effect is good but the corresponding delay is obvious. In case of sudden weather changes, the adjustment is lagging. If N is too small, the response is fast but the filtering effect is weak. In this embodiment, N is selected as 3 - 6. That is, when the sampling period is once per minute, it covers the data of 3 - 6 minutes. An array with a length of N is opened in the PLC to store historical data, and the pointer circularly overwrites the old data. Each time new data arrives, the oldest data is subtracted, the earliest data is removed from the cumulative sum, the new data is stored and the cumulative sum is updated.

[0033] Step 1.3, optimize the variant to reduce the lag of the illuminance value and improve the smoothness, so as to provide a faster response speed and a more accurate signal. The specific calculation formula is as follows: ; where , the smaller the value, the stronger the smoothing effect. Due to the limited PLC memory, using this calculation method for optimization can save memory space and the real-time calculation is simple.

[0034] Step 1.4, online monitor the filtering effect, record the data before and after filtering in the PLC, and regularly analyze the residuals (original value - filtered value) to ensure no systematic deviation.

[0035] Step 2, dynamically segment the tunnel and allocate illuminance to each segment; The tunnel is divided into several logical segments, including the entrance segment, the transition segment, the middle segment, and the exit segment. Each segment includes several lighting areas, and the target illuminance value of each segment is dynamically adjusted.

[0036] The illuminance requirements of the tunnel entrance segment, transition segment, middle segment, and exit segment are different: The entrance segment requires the highest illuminance, , where k in is the proportionality coefficient, with a value of 0.1 - 0.3, and E min is the international standard minimum threshold.

[0037] The illuminance of the transition segment needs to achieve a smooth transition from the high brightness of the entrance segment to the low brightness of the middle segment, avoiding visual sudden changes. When allocating illuminance, the brightness decreases in a gradient. Generally, it is divided into 1 - 3 sub - segments, and the brightness of each segment decreases to 1 / 3 - 1 / 2 of the brightness of the previous segment. The calculation formula is: , L n is the brightness of the current sub - segment, L n-1 is the brightness of the previous sub - segment, and β is the brightness attenuation coefficient, taking 1 / 3 - 1 / 2.

[0038] The illuminance of the middle segment is a fixed low illuminance, and the calculation formula is , where Q is the traffic flow coefficient, L is the length of the tunnel, and at the same time, it is necessary to ensure that Lm Not less than E min 。

[0039] The illuminance distribution in the exit section needs to be slightly higher than that in the middle section. The calculation formula is ,k out is the exit section proportion coefficient, with a value range of 1.5 - 5.

[0040] Step 3: Generate an illuminance curve from the spatial dimension. For the entire tunnel, with time as the horizontal axis and the illuminance of each lighting area as the vertical axis, generate a two-dimensional spatio-temporal illuminance surface. Divide 24 hours into 1440 time points in minutes, i.e., t = 1, 2,..., 1440, and assign the target illuminance to the lighting areas at each time point. The calculation formula is ,where L j (t)is the target illuminance of lighting area j at time point t, E out (t)is the external illuminance collected at time point t, d j is the distance of lighting area j from the tunnel entrance, and η is the attenuation coefficient.

[0041] Step 4: Generate an illuminance curve from the time dimension. Considering day and night and weather changes, generate a 24-hour illuminance curve. Connect the target illuminances within 24 hours in each lighting area in chronological order to form the time-illuminance curve of this lighting area. Dynamically adjust the illuminance of each lighting area during the day according to Step 2, and fix the basic lighting at night.

[0042] Step 5: Smoothly transition the illuminance values of each lighting area to avoid frequent jumps. Set a limit on the illuminance difference between adjacent lighting areas and use first-order lag filtering. The calculation formula is ,where is the smoothing factor, ,where is the actual illuminance value of lighting area j at time point t, is the target illuminance value of lighting area j at time point t.

[0043] Step two: Calibrate the actual illuminance of each lighting area in the tunnel to eliminate the illuminance error caused by lamp aging and dust occlusion, and eliminate the error caused by the deviation between the internal illuminance meter and the external illuminance meter. Specifically, it includes the following steps: Step 6: Benchmark calibration, with a frequency of once a month or after system maintenance, eliminate ambient light interference, and determine the basic hardware parameters; Step 6.1: Turn off all the LED lamps in the tunnel and read the data of the internal illuminance meters in each lighting area as the ambient background illuminance value L offset ; The ambient background illuminance value L offsetIt can eliminate the interference of ambient light. There may be natural light, vehicle lights or other stray lights in the tunnel, which will affect the true measurement of the LED illuminance. The actual illuminance contributed by the LED lamp is the measured illuminance of the illuminometer minus the ambient background illuminance value L offset ; The illuminometer may have a small output in a lightless environment. The ambient background illuminance value L offset is used to correct the small deviation of the illuminometer and correct the zero drift of the illuminometer, so that the calibrated illuminance data is consistent under different times or weather conditions, ensuring the comparability of the data.

[0044] Step 6.2, fully power on the LED lamps in each lighting area. After the LED lamps operate stably at 100% PWM, record the maximum illuminance value L maxj in each area. Subtract the local illuminance value L1 to obtain the actual maximum illuminance value of the LED lamp. Compare the actual maximum illuminance value with the assigned target illuminance value. It is necessary to meet the condition that the actual maximum illuminance value ≥ target illuminance value - tolerance. The tolerance is ±5% - 10% of the target illuminance value. If the standard is not met, find the reason and handle it.

[0045] Possible reasons and handling for non-compliance: Step 7, linearity calibration, once every quarter or after replacing the lamps, to solve the non-linear response problem of the LED lamps; Gradient test. Control the LED lamps to operate at 10%, 30%, 50%, 70%, 90%, and 100% power. After continuously operating for 1 minute at each PWM power control point, record the internal illuminometer values of each lighting area. Exclude transient effects. Measure 3 times at each power and take the average to obtain the data set: {(PWM1, L1), (PWM2, L2), ……, (PWM n , L n )}; Fitting curve, establish the PWM-illuminance relationship model. The formula for illuminance , where a, b, and c are storage coefficients, calculated using the built-in fitting function of the PLC. The system can eliminate non-linear errors and improve the illuminance control accuracy to within ±3%, achieving fast and accurate dimming.

[0046] Step 8, dynamic feedback calibration, continuously operate to correct short-term fluctuations and long-term aging errors in real time; Step 8.1, collect actual illuminance data in real time. The PLC reads the actual illuminance values detected by the internal illuminometers in each lighting area in real time through the 1# CAN bus unit, compares them with the theoretical illuminance values of the corresponding lighting areas determined according to the generated illuminance curve, and calculates the deviation ΔL between the actual illuminance value and the theoretical illuminance value; Step 8.2: Determine whether the deviation ΔL exceeds the preset threshold. A preset allowable deviation threshold of 5% of the theoretical illuminance is set in the PLC. If the deviation ΔL exceeds the threshold, it is considered that the illuminance of this area needs to be adjusted; Step 8.3: Adjust the illuminance of the LED lamps. For the lighting areas where the deviation exceeds the threshold, the PLC calculates the adjustment amount of the LED lamps according to the deviation magnitude. The PLC dynamically adjusts the PWM output through the PID algorithm. The calculation formula is as follows: ; where K p is the proportionality coefficient, used to quickly respond to the current deviation, K i is the integral coefficient, used to eliminate the steady-state error, K d is the differential coefficient, used to suppress overshoot, K p 、K i 、K d are determined through experiments.

[0047] After calibration, the system can handle emergencies (such as sudden drops in external light caused by heavy rain or thick fog), dynamically adjust the LED output to maintain safe lighting, and avoid over-illumination (such as automatically reducing PWM when the actual illuminance is higher than the demand), reducing energy waste.

[0048] After calibration, the steady-state error ≤ ±3% of the target value, the LED lamp adjustment response time is short, the step response from 50% of the target value to 100% ≤ 10 seconds, the anti-interference ability is strong, the transient disturbance recovery time ≤ 5 seconds, and the tunnel lighting system can achieve high-precision, adaptive and robust control, significantly improving safety and energy efficiency.

[0049] Step 3: The PLC controls the LED lamps in each lighting area according to the illuminance curve.

[0050] Send the illuminance adjustment signal of each area through the 3# bus unit CAN3; each area's LED dimmer corresponds to a station number j = 1, 2,..., N. The LED dimmers in each area receive the illuminance adjustment signal according to the station number and adjust the power of the LED lamps in their respective areas; the illuminometer in this area detects the illuminance in real time, sends the actual illuminance value, and sends it to the PLC through the 1# bus unit CAN1. The PLC judges whether the illuminance of each area meets the requirements according to the station number of this area. For areas with illuminance deviation, send the adjusted illuminance signal through the 3# bus unit again to make the illuminance of each area meet the requirements of the illuminance curve.

[0051] Due to the different illuminances outside the tunnel, the illuminance curves in different areas of the tunnel are also different. According to the requirements of tunnel lighting, the illuminance at the tunnel entrance should be the same as that outside the tunnel. As the distance increases, during the day, the illuminance gradually decreases and then gradually increases at the exit; at night, the illuminance gradually increases and then gradually decreases at the exit. For driving safety and to avoid visual discomfort and fatigue caused by the illuminance to the driver, the illuminance curves of different areas of the tunnel are pre-entered into the PLC according to industry standards. The PLC adjusts the power of the LED lamps based on the numerical feedback from each illuminometer to make the illuminance meet the requirements.

[0052] To avoid the problem of the tunnel lights being always on when there are no vehicles or few vehicles, a radar is installed at a distance of S meters from the tunnel entrance. When a vehicle passes by, the vehicle speed is detected as V, and the estimated time for the vehicle to reach the tunnel is , and the LED lamps at the tunnel entrance (area 1) are turned on 3 seconds before the vehicle enters the tunnel. The illuminance of the lamps is the same as that outside the tunnel; When the vehicle reaches the tunnel entrance, position sensor 1 is triggered, and the sensor signal is transmitted to the PLC through the bus unit CAN2. The PLC turns on the lighting in area 2 according to the station number of this sensor; When the vehicle travels to area 2, position sensor 2 is triggered, and the sensor signal is transmitted to the PLC through the bus unit CAN2. The PLC turns on the lighting in area 3 according to the station number of this sensor, and at the same time turns off the lighting in area 1; This cycle continues. Before reaching the tunnel exit, the lighting in the area behind the vehicle is turned off, and the lighting in the area where the vehicle is located and the previous area, a total of two areas, remains on until the vehicle exits the tunnel, and then all the tunnel lighting is turned off; When the vehicle stays in a certain area due to a fault or other reasons, since the position sensor in the next area is not triggered, the lighting in this area remains on until the vehicle exits; For the situation of heavy traffic and multiple vehicles entering an area, the PLC counts the number of times the position sensor is triggered. When the number of times the trigger in area N + 1 is equal to the number of times the trigger in area N, it means that all vehicles have exited area N, and the LED lamps in area N can be turned off (the output power of the LED dimmer in area N is 0%); Furthermore, for the situation of multiple lanes running in parallel, independent position sensors are installed in each lane, so there may be multiple position sensors in one area; for example, in area N with two lanes, if only one position sensor is installed, when two vehicles are running in parallel, it is possible that the sensor only senses one vehicle. To prevent such situations, two independent sensors, N1 and N2, are installed in area N. When counting the number of vehicles entering and exiting, the total value of N1 + N2 can be calculated.

[0053] For example, in area N with a two-lane road, the left-lane sensor N1 is triggered A times and the right-lane sensor N1 is triggered B times. The total number of trigger times is A + B times. If the total number of times the two sensors in the left and right lanes in area N+1 are triggered is equal to A + B, it means that all vehicles in area N have exited, and the LED lights in area N can be turned off (the output power of the LED dimmer in area N is 0%); if the total number of times the two sensors in the left and right lanes in area N+1 are triggered is less than A + B, it means that there are still vehicles in area N, and the LED lights in area N cannot be turned off.

[0054] Step Four, the exception handling mechanism; Illuminometer failure: If the data in a certain area exceeds the limit or remains unchanged, the average value of the adjacent area is used for substitution.

[0055] Communication interruption: The 1# bus unit CAN1, 2# bus unit CAN2, and 3# bus unit CAN3 are redundantly designed, and the last valid illuminance curve is maintained after the timeout.

[0056] Extreme weather: When the external illuminance drops suddenly, immediately switch to the highest lighting level.

[0057] Step Five, the control of the power generation amount of the photovoltaic power generation panel.

[0058] Since the designed power of the photovoltaic power is based on the maximum traffic flow, when there is sufficient sunlight and the photovoltaic power generation is large, and the traffic flow is small and the tunnel lighting power consumption is low, after the photovoltaic power generation fully charges the battery for night lighting, there is still surplus photovoltaic power generation.

[0059] Due to weather reasons, such as continuous rainy days with insufficient sunlight and low photovoltaic power generation, and large traffic flow and high tunnel lighting power consumption, the battery cannot be fully charged during the day and it is difficult to maintain the tunnel night lighting power consumption, resulting in a shortage of photovoltaic power generation.

[0060] To address the above situations and ensure the safety of tunnel driving, it is necessary to form a complementarity between the national power grid and the photovoltaic power.

[0061] When there is surplus photovoltaic power generation, on the premise of ensuring the tunnel power consumption, the photovoltaic power generation feeds back to the national power grid.

[0062] When there is a shortage of photovoltaic power generation, the national power grid supplements the shortage part of the photovoltaic power generation to ensure the tunnel power consumption.

[0063] The input terminals of the reference voltage generator are connected in parallel to the power output terminal of the photovoltaic power generation panel. The output terminal of the reference voltage generator outputs two standard voltages U1 and U2. The standard voltage U1 is the threshold voltage for upward grid-connected power generation, and the standard voltage U2 is the threshold voltage for downward power consumption.

[0064] The non-inverting terminal (+ sign) of the 1# voltage comparator is connected to the positive pole of the photovoltaic power generation panel, the inverting terminal (- sign) of the 1# voltage comparator is connected to the U1 terminal of the reference voltage generator, and the output terminal of the 1# voltage comparator is connected to the 1# relay coil.

[0065] The inverting terminal (- sign) of the 2# voltage comparator is connected to the positive pole of the photovoltaic power generation panel, the non-inverting terminal (+ sign) of the 2# voltage comparator is connected to the U2 terminal of the reference voltage generator, and the output terminal of the 2# voltage comparator is connected to the 2# relay coil.

[0066] The output voltage of the photovoltaic power generation panel is used to charge the storage battery through the charge and discharge management module. When the weather is sunny and there is sufficient sunlight, the output voltage of the photovoltaic power generation panel is relatively high, and the charging speed of the storage battery is fast. When the storage battery is full and the traffic flow in the tunnel is small, the output voltage of the photovoltaic power generation panel rises to reach the upward grid-connected power generation threshold voltage U1, and the output terminal of the 1# voltage comparator is at a high level. The 1# relay coil is energized and attracted, and the 1# relay contact is closed. The photovoltaic power generation is connected to the grid for upward power generation through the inverter.

[0067] When the light is insufficient and the photovoltaic power generation is small, the charging of the storage battery is insufficient, and the output voltage of the photovoltaic power generation panel is pulled down by the storage battery. The output voltage of the photovoltaic power generation panel drops to reach the downward power consumption threshold voltage U2, and the output terminal of the 2# voltage comparator is at a high level. The 2# relay coil is energized and attracted, and the 2# relay contact is closed. The national power grid supplements the photovoltaic power through the rectifier and voltage regulator.

[0068] Furthermore, in the case of sufficient sunlight and continuous traffic flow in the tunnel, the photovoltaic power generation power is designed to just meet the tunnel power consumption requirements. The photovoltaic system does not need to connect to the national power grid for upward power generation and downward power consumption through relays. Suppose the output voltage U0 of the photovoltaic power generation panel at this time is 95V, and there is U1 < U0 < U2.

[0069] For example, U1 = 105V, U2 = 95V, and U0 is between 95V and 105V. The photovoltaic power generation just meets the tunnel power consumption requirements.

[0070] When U0 rises to 105V, it means that there is surplus photovoltaic power generation and upward grid-connected power generation is required.

[0071] When U0 drops to 95V, it means that there is a gap in photovoltaic power generation and downward power consumption supplement is required.

[0072] The description of the present invention is given for purposes of illustration and description, and is not intended to be exhaustive or to limit the invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are chosen and described in order to best explain the principles of the invention and its practical application, and to enable those of ordinary skill in the art to understand the invention and design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A tunnel lighting photovoltaic power supply system with light intensity self - adaptation, characterized in that: It includes a photovoltaic power generation panel. The positive and negative electrodes of the photovoltaic power generation panel output a power supply L1 line and an N1 line. The power supply L1 line and the N1 line are connected to a PLC. The PLC is connected to a 1# bus unit CAN1, a 2# bus unit CAN2, and a 3# bus unit CAN3. From the tunnel entrance to the exit, N different lighting areas are divided. A position sensor is installed at the front end of each lighting area. An LED lamp and an illuminance meter are installed at the middle position of each lighting area. The 1# bus unit CAN1 is connected to N internal illuminance meters and an external illuminance meter. The data of each internal illuminance meter is transmitted to the PLC in real time through the bus. The external illuminance meter is installed outside the tunnel and is used to detect the external environment illuminance of the tunnel; Internal illuminance meters are installed in each lighting area inside the tunnel. The N internal illuminance meters can detect the actual illuminance of each lighting area. The 2# bus unit CAN2 is connected to an entrance radar and N position sensors. The position sensors are installed in each lighting area inside the tunnel. When a vehicle triggers a position sensor, it means entering that lighting area. When a vehicle triggers the next position sensor, it means leaving the previous lighting area. The 3# bus unit CAN3 is connected to N LED dimmers. The LED dimmers use PWM regulation to achieve dimming of the LED lamps. Each LED dimmer is connected to an LED lamp. The PLC transmits an illuminance adjustment signal to the LED dimmers through the 3# bus unit CAN3 bus, and can adjust the output power from 0% - 100%, so that the illuminance of the LED lamps changes from 0% - 100%.

2. The tunnel lighting photovoltaic power supply system with adaptive light intensity as claimed in claim 1, wherein: The power supply L1 line and the N1 line are also connected to an inverter and a rectifier, and are connected to the national power grid through the inverter and the rectifier. The power supply L1 line and the N1 line are connected to a reference voltage generator. The reference voltage generator is connected to a 1# voltage comparator and a 2# voltage comparator. One end of the 1# relay coil is connected to the 1# voltage comparator, and the other end of the 1# relay coil is grounded. One end of the 2# relay coil is connected to the 2# voltage comparator, and the other end of the 2# relay coil is grounded; The power supply L1 line and the N1 line are also connected to a charge-discharge management module, and the charge-discharge management module is connected to a battery pack.

3. Implementation method of a tunnel lighting photovoltaic power supply system with adaptive light intensity, characterized in that: The implementation method is applied to the tunnel lighting photovoltaic power supply system with self-adaptive light intensity as described in any one of claims 1 - 2, and includes the following steps: Step 1, the PLC generates an illuminance curve for each lighting area inside the tunnel according to the received value of the external illuminance meter; Step 2, calibrate the actual illuminance of each lighting area inside the tunnel, eliminate the illuminance error caused by lamp aging and dust occlusion, and eliminate the error caused by the deviation between the internal illuminance meter and the external illuminance meter; Step 3, the PLC controls the LED lamps in each lighting area according to the illuminance curve; Step 4, an exception handling mechanism; Illuminance meter failure: If the data of a certain area exceeds the limit or remains unchanged, enable the average value substitution of adjacent areas; Communication interruption: The 1# bus unit CAN1, the 2# bus unit CAN2, and the 3# bus unit CAN3 are redundantly designed, and maintain the last effective illuminance curve after timeout; Extreme weather: When the external illuminance drops suddenly, immediately switch to the highest lighting level; Step 5, control the photovoltaic power generation amount of the photovoltaic power generation panel; When there is surplus photovoltaic power generation, on the premise of ensuring the power consumption of the tunnel, the photovoltaic power generation feeds back to the national power grid; when there is a shortage of photovoltaic power generation, the national power grid supplements the shortage part of the photovoltaic power generation to ensure the power consumption of the tunnel. The input terminals of the reference voltage generator are connected in parallel to the power output terminals of the photovoltaic panels. The output terminals of the reference voltage generator output two standard voltages U1 and U2. The standard voltage U1 is the threshold voltage for upward grid-connected power generation, and the standard voltage U2 is the threshold voltage for downward power consumption. The output voltage of the photovoltaic panels is used to charge the battery through the charge and discharge management module. When the weather is sunny and there is sufficient sunlight, the output voltage of the photovoltaic panels is relatively high, and the battery charges quickly. When the battery is fully charged and the traffic flow in the tunnel is small, the output voltage of the photovoltaic panels rises to reach the upward grid-connected power generation threshold voltage U1. The output terminal of the 1# voltage comparator is at a high level, the coil of the 1# relay is energized and attracted, the contacts of the 1# relay are closed, and the photovoltaic power generation is connected to the grid upward through the inverter. When the light is insufficient and the photovoltaic power generation is small, the battery is not fully charged, and the output voltage of the photovoltaic panels is pulled down by the battery. The output voltage of the photovoltaic panels drops to reach the downward power consumption threshold voltage U2. The output terminal of the 2# voltage comparator is at a high level, the coil of the 2# relay is energized and attracted, the contacts of the 2# relay are closed, and the national power grid supplements the photovoltaic through the rectifier and voltage regulator. In the case of sufficient sunlight and continuous traffic flow in the tunnel, the photovoltaic power generation is designed to just meet the power consumption requirements of the tunnel. The photovoltaic system does not need to be connected to the national power grid for upward power generation and downward power consumption through relays. Assume that the output voltage U0 of the photovoltaic panels at this time is 95V, and U1 < U0 < U2.

4. The implementation method of the tunnel lighting photovoltaic power supply system with adaptive light intensity as claimed in claim 3, characterized in that: The first step includes the following steps: Step 1, data collection and preprocessing; Step 2, dynamically segment the tunnel and allocate illuminance to each segment; Step 3: Generate an illuminance curve from the spatial dimension. For the entire tunnel, with time as the horizontal axis and the illuminance of each lighting area as the vertical axis, generate a two-dimensional spatio-temporal illuminance surface. Divide 24 hours into 1440 time points in minutes, i.e., t = 1, 2,..., 1440, and assign the target illuminance to the lighting areas at each time point. The calculation formula is , where Lj(t) is the target illuminance of lighting area j at time point t, Eout(t) is the external illuminance collected at time point t, dj is the distance of lighting area j from the tunnel entrance, and η is the attenuation coefficient; Step 4, generate an illuminance curve from the time dimension, considering day and night, weather changes, generate a 24-hour illuminance curve, connect the target illuminance within 24 hours in each lighting area in chronological order to form the time-illuminance curve of this lighting area. During the day, dynamically adjust the illuminance of each lighting area according to Step 2, and fix the basic lighting at night. Step 5: Smooth the illuminance values of each lighting area to avoid frequent jumps, limit the illuminance difference between adjacent lighting areas, and use first-order lag filtering. The calculation formula is , where is the smoothing factor, , where is the actual illuminance value of lighting area j at time point t, is the target illuminance value of lighting area j at time point t.

5. The implementation method of the tunnel lighting photovoltaic power supply system with adaptive light intensity as claimed in claim 4, characterized in that: The data collection and preprocessing include the following steps: The internal illuminance Ein of the tunnel, read the internal illuminance meters of each lighting area, and mark the corresponding area numbers j = 1, 2,..., N; The external illuminance Eout of the tunnel, the PLC periodically reads the data of the external illuminance meter through the 1# bus unit CAN1, and smooths the collected external illuminance values to eliminate the instantaneous fluctuations in the data and improve the stability and reliability of the tunnel lighting system. The specific process is as follows: Step 1.1, use the arithmetic mean of the illuminance values of the past N sampling points as the current output value to weaken the random fluctuations: ； Among them, Yn is the output value after filtering the data of the external illuminance meter; Xn-i is the original illuminance value data of the nth sampling; N is the size of the sliding window; Step 1.2: Set the sliding window size N in the PLC. N is selected to be 3 - 6. That is, when the sampling period is once per minute, it covers data of 3 - 6 minutes. Open an array with length N in the PLC to store historical data. The pointer circularly overwrites the old data. Each time new data arrives, subtract the oldest data, remove the earliest data from the cumulative sum, store the new data and update the cumulative sum; Step 1.3: Optimize the variant to reduce the lag of illuminance values and improve smoothness, thereby providing a faster response speed and a more accurate signal. The specific calculation formula is as follows: ; among which ; Step 1.4: Online monitor the filtering effect, record the data before and after filtering in the PLC, and regularly analyze the residuals to ensure no systematic deviation.

6. The implementation method of the tunnel lighting photovoltaic power supply system with adaptive light intensity as claimed in claim 4, characterized in that: The specific process of dynamically segmenting the tunnel and allocating illuminance to each segment is as follows: Divide the tunnel into several logical segments, including the entrance segment, transition segment, middle segment, and exit segment. Each segment includes several lighting areas, and dynamically adjust the target illuminance values of each segment; The illuminance requirements of the tunnel entrance segment, transition segment, middle segment, and exit segment are all different: The entrance section requires the highest illuminance, , where kin is the proportionality coefficient with a value range of 0.1 - 0.3, and Emin is the lowest threshold of the international standard; The illuminance of the transition section needs to achieve a smooth transition from the high brightness of the entrance section to the low brightness of the middle section to avoid sudden visual changes. When allocating illuminance, the brightness decreases in a gradient and is divided into 1-3 subsections. The brightness of each subsection decreases to 1 / 3-1 / 2 of the brightness of the previous subsection. The calculation formula is: , where Ln is the brightness of the current subsection, Ln-1 is the brightness of the previous subsection, and β is the brightness attenuation coefficient, taking 1 / 3-1 / 2; The illuminance of the middle section is a fixed low illuminance, and the calculation formula is , where Q is the traffic flow coefficient, L is the tunnel length, and it is necessary to ensure that Lm is not lower than Emin; The illuminance distribution in the exit section needs to be slightly higher than that in the middle section, and the calculation formula is , where kout is the proportionality coefficient of the exit section, and its value ranges from 1.5 to 5.

7. The implementation method of the tunnel lighting photovoltaic power supply system with adaptive light intensity as claimed in claim 3, characterized in that: The second step includes the following steps: Step 6: Baseline calibration, with a frequency of once per month or after system maintenance, eliminate ambient light interference, and determine the basic hardware parameters; Step 7: Linearity calibration, with a frequency of once per quarter or after replacing the lamps, solve the non - linear response problem of LED lamps; Gradient test: Control the LED lamps to operate at 10%, 30%, 50%, 70%, 90%, and 100% power. After continuously operating for 1 minute at each PWM power control point, record the internal illuminometer values of each lighting area. Exclude transient effects, measure 3 times for each power and take the average to obtain a data set: {(PWM1, L1), (PWM2, L2), ……, (PWMn, Ln)}; Fitting curve to establish the PWM-illuminance relationship model, the formula for illuminance is , where a, b, and c are storage coefficients, calculated using the built-in fitting function of the PLC. The system can eliminate non-linear errors, improve the illuminance control accuracy to within ±3%, and achieve fast and accurate dimming; Step 8: Dynamic feedback calibration, continuously operate to correct short - term fluctuations and long - term aging errors in real - time.

8. The implementation method of the tunnel lighting photovoltaic power supply system with adaptive light intensity as claimed in claim 7, wherein: The step 6 includes the following steps: Step 6.1: Turn off all the LED lamps in the tunnel, read the internal illuminometer data of each lighting area as the ambient background illuminance value Loffset; The ambient background illuminance value Loffset can eliminate ambient light interference. The actual contributed illuminance of the LED lamps is the measured illuminance by the illuminometer minus the ambient background illuminance value Loffset; The illuminometer has a small output in a light - free environment. The ambient background illuminance value Loffset is used to correct the small deviation of the illuminometer, correct the zero - point drift of the illuminometer, so that the calibrated illuminance data has consistency at different times or weather conditions, and ensure the comparability of the data; Step 6.2: Fully light up the LED lamps in each lighting area. After the LED lamps operate stably at 100% PWM, record the maximum illuminance value Lmaxj of each area. Subtract the local illuminance value L1 to obtain the actual maximum illuminance value of the LED lamps. Compare the actual maximum illuminance value with the allocated target illuminance value. It is required to meet the condition that the actual maximum illuminance value ≥ target illuminance value - tolerance. The tolerance is ±5% - 10% of the target illuminance value. If not up to the standard, find the reason and deal with it.

9. The implementation method of the tunnel lighting photovoltaic power supply system with adaptive light intensity as claimed in claim 7, wherein: The step 8 includes the following steps: Step 8.1: Collect actual illuminance data in real time. The PLC reads in real time the actual illuminance values detected by the internal illuminance meters in each lighting area through the 1# CAN bus unit, compares them with the theoretical illuminance values of the corresponding lighting areas determined according to the generated illuminance curve, and calculates the deviation ΔL between the actual illuminance value and the theoretical illuminance value. Step 8.2: Determine whether the deviation ΔL exceeds the preset threshold. A preset allowable deviation threshold of 5% of the theoretical illuminance is set in the PLC. If the deviation ΔL exceeds the threshold, it is considered that the illuminance of this area needs to be adjusted. Step 8.3: Adjust the illuminance of the LED lamps. For the lighting areas where the deviation exceeds the threshold, the PLC calculates the adjustment amount of the LED lamps according to the deviation magnitude. The PLC dynamically adjusts the PWM output through the PID algorithm, and the calculation formula is as follows: ； where Kp is the proportionality coefficient, used to quickly respond to the current deviation, Ki is the integral coefficient, used to eliminate the steady-state error, Kd is the differential coefficient, used to suppress overshoot, and Kp, Ki, and Kd are determined through experiments.

10. The implementation method of the tunnel lighting photovoltaic power supply system with adaptive light intensity as claimed in claim 3, characterized in that: In Step 3, the PLC controls the LED lamps in each lighting area according to the illuminance curve. The specific process is as follows: Send out the illuminance adjustment signal for each area through the 3# bus unit CAN3; each area's LED dimmer corresponds to a station number j = 1, 2,..., N. The LED dimmers in each area receive the illuminance adjustment signal according to the station number and adjust the power of the LED lamps in their respective areas; the illuminance meter in this area detects the illuminance in real time, sends the actual illuminance value, and sends it to the PLC through the 1# bus unit CAN1. The PLC judges whether the illuminance of each area meets the requirements according to the station number of this area. For areas with illuminance deviation, send the adjusted illuminance signal through the 3# bus unit again to make the illuminance of each area meet the requirements of the illuminance curve. Due to the different illuminances outside the tunnel, the illuminance curves of each area in the tunnel are also different. According to the requirements of tunnel lighting, the illuminance at the tunnel entrance should be the same as the illuminance outside the tunnel. As the distance deepens, in the daytime, the illuminance gradually decreases and then gradually increases at the exit; in the nighttime, the illuminance gradually increases and then gradually decreases at the exit; for driving safety, to avoid visual discomfort and fatigue caused by the illuminance to the driver, the illuminance curves of each area in the tunnel are pre-entered into the PLC according to industry standards. The PLC adjusts the power of the LED lamps according to the numerical feedback of each illuminance meter to make the illuminance meet the requirements. To avoid the problem of no vehicles or few vehicles passing through while the tunnel lights are always on, a radar is installed at a distance of S meters from the tunnel entrance. When a vehicle passes by, the vehicle speed is detected as V, and the estimated time for the vehicle to reach the tunnel is , and the LED lights at the tunnel entrance are turned on 3 seconds before the vehicle enters the tunnel, and the illuminance of the lights is the same as that outside the tunnel; When the vehicle arrives at the tunnel entrance, position sensor 1 is triggered, and the sensor signal is transmitted to the PLC through the bus unit CAN2. The PLC turns on the lighting in area 2 according to the sensor station number. When the vehicle travels to area 2, position sensor 2 is triggered, and the sensor signal is transmitted to the PLC through the bus unit CAN2. The PLC turns on the lighting in area 3 according to the sensor station number and turns off the lighting in area 1 at the same time. This cycle continues. Before reaching the tunnel exit, the lighting in the area behind the vehicle is turned off, and the lighting in the area where the vehicle is located and the previous area, a total of two areas, remains on until the vehicle exits the tunnel and all the tunnel lighting is turned off. When the vehicle stays in a certain area due to a fault or other reasons, since the next area position sensor is not triggered, the lighting in this area remains on until the vehicle exits. For the situation where there is a large traffic flow and multiple vehicles enter a region, the PLC counts the number of trigger times of the position sensor. When the number of trigger times of the trigger in the N+1 region is equal to the number of trigger times of the trigger in the N region, it indicates that all vehicles have exited the N region, and the LED lights in the N region can be turned off.

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