Intelligent constant-temperature heat dissipation and brightness cooperative control system of LED display terminal

Abstract

The invention relates to the technical field of non-electrical variable control, and discloses an intelligent constant-temperature heat dissipation and brightness cooperative control system of an LED display terminal, which comprises a virtual thermal field construction module, an execution state observation module, a boundary condition resolving module and a feedforward control correction module, and is characterized in that the system generates a virtual thermal field according to a video frame; according to the method, cooling flux mismatch caused by drifting of environment boundary conditions is eliminated through a flow resistance observation mechanism, self-adaptive disturbance suppression of the unstructured fluid environment is achieved, the heat dissipation efficiency is improved, and the heat dissipation efficiency is improved. The problem of photo-thermal response time domain mismatching is solved, and heat balance and display stability of the system under complex working conditions are ensured.

Description

Technical Field

[0001] This invention relates to an intelligent constant temperature heat dissipation and brightness coordinated control system for LED display terminals, belonging to the field of non-electric variable control technology. Background Technology

[0002] Current thermal management solutions for LED display terminals mostly adopt a single-loop control architecture based on temperature sensor feedback. This architecture collects real-time temperature data from the PCB board or module area using a thermistor, and then uses a PID algorithm to calculate the deviation and adjust the cooling fan speed to maintain the set temperature. However, this hysteresis feedback mechanism is insufficient when dealing with high dynamic video streams or outdoor fluid environments.

[0003] To overcome the limitations of air cooling, existing technologies attempt to stack hardware to increase system heat capacity. For example, the utility model patent with authorization announcement number CN201363702Y discloses a cooling and heat dissipation system for LED displays, which constructs a liquid-cooled closed loop including a heat absorber, a circulating pump, and an external heat sink. It utilizes the high specific heat capacity of the liquid working fluid to alleviate the heat dissipation pressure under high-temperature conditions. Although such solutions improve the hardware structure, they do not fundamentally solve the problem of control logic lag. The operating mechanism is still limited by the passive response triggered by the temperature threshold. Faced with nanosecond-level photoelectric and thermal abrupt changes in LEDs, the inherent inertia of fluid medium circulation and physical heat conduction causes a time-domain lag in cooling action due to the step change in the heat source. Furthermore, simple hardware stacking does not establish a sense of the external unstructured environment. The current system lacks the ability to compensate for changes in outdoor natural wind back pressure, filter dust accumulation, or pipeline flow resistance. This hysteresis feedback mechanism has shortcomings when handling high-dynamic video streams or outdoor fluid environments: time-domain mismatch in photothermal response; LED photoelectric response is in the nanosecond range; heat conduction and sensor response are limited by thermal capacity, resulting in minute-level physical lag; delayed heat dissipation leads to sudden heating changes; instantaneous junction temperature overshoot under high-brightness conditions causes brightness thermal decay or color drift; dynamic drift in execution boundary conditions; the control model presets constant output characteristics of the heat dissipation mechanism, failing to consider changes in flow channel impedance caused by outdoor natural wind back pressure, filter dust accumulation, or bearing wear; the controller output duty cycle command cannot be converted into the expected cooling flux, decoupling the logic control quantity from the physical execution quantity.

[0004] Therefore, how to establish a control mechanism that overcomes thermal inertia hysteresis and senses changes in physical execution boundaries in real time, and eliminate the effects of photothermal temporal mismatch and environmental disturbances on the steady state of the system, has become the technical problem to be solved by this invention. Summary of the Invention

[0005] To address the problems mentioned in the background art, the technical solution of the present invention is as follows: An intelligent constant temperature heat dissipation and brightness coordinated control system for an LED display terminal, comprising: The virtual thermal field construction module is used to receive video stream frame data to be displayed, call the preset photothermal conversion model to calculate the theoretical heat generation of each pixel in the video stream frame data, and perform spatial domain superposition operation on the theoretical heat generation to generate virtual thermal field distribution data. The execution status observation module is used to synchronously collect the real-time speed feedback value of the heat dissipation actuator and the bus current value of the drive circuit during the operation of the heat dissipation actuator in response to the drive command. The boundary condition calculation module is used to call the preset fan operation characteristic model, calculate the operation deviation of the real-time speed feedback value and bus current value relative to the reference state, and calculate the equivalent flow resistance coefficient that characterizes the current environmental wind resistance based on the positive and negative polarity of the operation deviation. The feedforward control correction module is used to generate basic heat dissipation control commands based on virtual thermal field distribution data, and to perform gain compensation on the basic heat dissipation control commands using the equivalent flow resistance coefficient, thereby generating the final drive command that matches the current environmental wind resistance to drive the heat dissipation actuator. Among them, the fan operation characteristic model records the correspondence between different drive duty cycles and reference speed and reference current under standard ventilation impedance conditions. The feedforward control correction module compensates for the actual air volume reduction caused by intake blockage or exhaust backdraft by introducing the equivalent flow resistance coefficient.

[0006] Preferably, the boundary condition calculation module is specifically used to perform the following steps: based on the currently issued drive duty cycle command, query the corresponding reference speed value and reference current value in the fan operation characteristic model; calculate the speed deviation between the real-time speed feedback value and the reference speed value, and the current deviation between the bus current value and the reference current value; when the speed deviation is greater than a preset positive threshold and the current deviation is less than a preset negative threshold, determine that the current heat dissipation channel is in an intake obstruction state, and generate an equivalent flow resistance coefficient with a value greater than one; when the speed deviation is less than a preset negative threshold and the current deviation is greater than a preset positive threshold, determine that the current heat dissipation channel is in an exhaust backflow state, and generate an equivalent flow resistance coefficient with a value greater than one.

[0007] Preferably, the feedforward control correction module follows the following gain correction formula when generating the final drive command: ,in, The output duty cycle corresponding to the final drive instruction. This is the base duty cycle calculated solely based on virtual thermal field distribution data. The equivalent flow resistance coefficient output by the boundary condition solution module. This is the starting compensation value used to offset the static friction resistance of the heat dissipation actuator; the feedforward control correction module uses this formula to ensure that the effective air volume output by the heat dissipation actuator matches the heat dissipation demand represented by the virtual thermal field distribution data under different wind resistance environments.

[0008] Preferably, it also includes a timing alignment control module for establishing a photothermal response synchronization mechanism; the timing alignment control module obtains the response delay time of the heat dissipation actuator and performs advance processing on the execution time of the final drive instruction based on the response delay time to generate a preloaded drive instruction; the timing alignment control module sends the preloaded drive instruction to the heat dissipation actuator and controls the heat dissipation actuator to start acceleration before the display of the screen corresponding to the video stream frame data, so that the peak time of the heat dissipation airflow is synchronized with the arrival time of the peak heat generation of the LED light board.

[0009] Preferably, it also includes a thermal saturation arbitration module for performing zoned brightness adjustment when the heat dissipation capacity is insufficient; the thermal saturation arbitration module calculates the total heat load corresponding to the virtual thermal field distribution data in real time and compares the total heat load with the maximum heat dissipation power of the heat dissipation actuator; when the total heat load exceeds the maximum heat dissipation power, the thermal saturation arbitration module activates the non-uniform current adjustment mode; in the non-uniform current adjustment mode, the thermal saturation arbitration module generates a visual weight map based on the image frequency characteristics of the video stream frame data, and performs a priority reduction operation on the driving current of pixels in low-weight areas according to the visual weight map, until the corrected total heat load is not higher than the maximum heat dissipation power.

[0010] Preferably, when the thermal saturation arbitration module performs non-uniform current regulation mode, it identifies high-frequency texture regions and skin color regions in the video stream frame data and marks them as high-weight regions, while identifying low-frequency background regions and marking them as low-weight regions. The thermal saturation arbitration module maintains the drive current of the high-weight regions unchanged and allocates the overflow portion of the total heat load that exceeds the maximum heat dissipation power to the low-weight regions for current reduction.

[0011] Preferably, it also includes a state correction module for performing benchmark calibration during the display idle period; the state correction module monitors the grayscale data of the video stream frame data and identifies the idle period of the all-black frame or low grayscale frame; during the idle period, the state correction module collects the temperature sensor value at the LED light panel and uses the value as the ambient reference temperature to correct the thermal calculation parameters of the photothermal conversion model to eliminate the prediction error caused by the ambient temperature drift.

[0012] Preferably, it also includes a thermal characteristic diagnostic module for monitoring the health status of the heat dissipation components; the thermal characteristic diagnostic module identifies the moment when brightness changes suddenly in the video stream frame data as the excitation start point, and records the temperature change curve after the excitation start point; the thermal characteristic diagnostic module compares the temperature change curve with the theoretical temperature rise curve derived based on the virtual thermal field distribution data, calculates the response time difference and steady-state temperature difference between the two, and generates a diagnostic signal for aging of the heat dissipation components or abnormal contact thermal resistance when the response time difference or steady-state temperature difference exceeds the preset range.

[0013] Preferably, it also includes a dynamic cooling capacity allocation module for improving local brightness by utilizing thermal capacity margin; the dynamic cooling capacity allocation module calculates the difference between the total heat load and the maximum heat dissipation power in real time as the heat dissipation margin at the current moment; the dynamic cooling capacity allocation module identifies local bright areas in the video stream frame data, and within the allowable range of heat dissipation margin, generates a drive current command higher than the rated value to drive the local bright areas, and uses the transient thermal capacity of the system to absorb the additional heat generated.

[0014] Preferably, the photothermal conversion model includes a preset current-luminous efficacy characteristic table; the virtual thermal field construction module is used to analyze the proportion of input power converted into light energy and the proportion converted into heat energy in each pixel of the video stream frame data according to the current-luminous efficacy characteristic table, and to calculate heat energy using a high luminous efficacy coefficient for low grayscale pixels and a low luminous efficacy coefficient for high grayscale pixels, so as to construct heat source distribution data that conforms to the physical characteristics of LED devices.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In the intelligent constant temperature heat dissipation of LED display terminals, an actuator state observation mechanism is constructed. By utilizing the deviation between the real-time electrical feedback parameters and the reference manifold during the operation of the heat dissipation actuator, the equivalent flow resistance coefficient characterizing the environmental back pressure and flow channel impedance is calculated. The traditional open-loop feedforward control is upgraded to a closed-loop control system with disturbance suppression capability. The gain parameters of the photothermal conversion model are dynamically corrected according to the equivalent flow resistance coefficient to ensure that the actual output cooling flux and the predicted heat load demand are accurately matched under non-ideal physical boundary conditions such as outdoor headwinds, filter dust accumulation, or bearing wear. This eliminates the steady-state temperature fluctuation of the system caused by the drift of the physical characteristics of the actuator layer.

[0016] 2. Establish nonlinear photothermal mapping and spatial convolution logic for video stream information, construct an advanced physical conduction virtual thermal field distribution in the logic domain, perform temporal forward shift on the virtual thermal field data based on the thermal response time constant of the heat dissipation channel, generate preloaded heat dissipation instructions, so that the arrival time of the peak heat dissipation airflow is precisely aligned with the actual peak heat dissipation time of the LED array on the time axis. The spatiotemporal coordination mechanism overcomes the physical inertial lag of the thermal system from the root, and avoids instantaneous overshoot of junction temperature due to heat dissipation response delay when the display screen changes drastically, and avoids brightness flicker or color drift caused by this delay.

[0017] 3. A multi-objective optimization arbitration strategy based on human visual characteristics is introduced to calculate the thermal saturation index in real time. When the saturation threshold is triggered, a visual weight map is generated based on the spatial frequency characteristics of the video frame. The non-uniform attenuation of the driving current is prioritized for the background area or low-weight area. Under the premise of complying with physical heat dissipation limits and protecting hardware safety, the limited heat quota is redistributed to maintain the peak brightness and contrast of the area, achieving a dynamic balance between objective physical constraints and subjective visual experience. The display terminal originally used to play video signals is reused as the excitation source of the thermal system. The transient thermal response characteristics of the screen brightness step change are captured, and a thermal residual fingerprint representing the physical state of the heat dissipation path is constructed. The differences in time constant and amplitude between the theoretical temperature rise curve and the actual sampling curve are compared to identify the aging of the heat conduction medium, heat pipe failure, or early hidden structural degradation due to increased contact thermal resistance. By utilizing the characteristics of the video stream itself, preventive maintenance monitoring of the entire life cycle of the heat dissipation system can be achieved without adding dedicated detection hardware or interrupting normal display services. Attached Figure Description

[0018] Figure 1 This is a block diagram illustrating the principle of the collaborative control system for virtual thermal field and flow resistance observation in this invention. Figure 2 A comparison curve of transient temperature response and heat load for introducing a timing alignment mechanism in this invention; Figure 3 This is a diagram showing the data interaction logic and closed-loop control signal flow between the modules of the system of this invention. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] This invention discloses an intelligent constant-temperature heat dissipation and brightness coordinated control system for an LED display terminal. It comprises a virtual thermal field construction module, an execution state observation module, a boundary condition calculation module, a feedforward control correction module, a timing alignment control module, a thermal saturation arbitration module, and a state correction module. These modules work collaboratively via a data bus to construct a dual closed-loop control loop for non-electrical variables, namely temperature and luminous flux. The first loop establishes a virtual thermal field that anticipates physical conduction based on the energy characteristics of video stream data. The second loop utilizes the electromechanical feedback characteristics of the heat dissipation actuator to establish an observation mechanism for environmental flow resistance disturbances. These two loops coordinate in the time and spatial domains to solve the time-domain mismatch of the LED display terminal's photothermal response and the instability of heat dissipation control in outdoor unstructured fluid environments. The system also addresses the LED luminous response... To address the temporal mismatch challenge caused by the minute-level thermal conduction response while the target is only nanosecond-level, the system establishes a mapping from the data domain to the physical domain through a virtual thermal field construction module. This module receives the video stream frame data to be displayed and calls a pre-set photothermal conversion model to perform pixel-level energy consumption analysis. This photothermal conversion model is built based on the external quantum efficiency curve (Droop curve) of the LED chip and internally stores a nonlinear mapping table between current density and heat dissipation coefficient. For each pixel in the video stream frame data, the module reads its RGB grayscale value and queries the mapping table. For low grayscale pixels, the model matches a higher light conversion efficiency coefficient; for high grayscale pixels, the model matches a higher heat dissipation coefficient, thereby calculating the theoretical heat generation per pixel. The module introduces a pre-set thermal diffusion convolution kernel, for example... or The matrix performs spatial domain convolution operations on the theoretical heat generation of a single pixel to simulate the lateral heat conduction process on the PCB substrate and aluminum housing, generating virtual thermal field distribution data corresponding to the current video frame. This process transforms the invisible future heat load into a quantifiable digital matrix.

[0021] To address the objective obstacles commonly faced by outdoor display terminals, such as reverse back pressure from natural wind and dust accumulation on filters, which cause the physical boundary conditions of the heat dissipation actuator to drift, the system is equipped with an execution status observation module and a boundary condition calculation module. The cooling fan is reused as a fluid impedance sensor. The execution status observation module is electrically connected to the cooling fan's drive circuit. While the cooling fan operates in response to drive commands, it simultaneously acquires the fan's real-time speed feedback value and drive bus current value at a sampling frequency of no less than 10Hz. The real-time speed feedback value is obtained from the FG signal terminal, and the drive bus current value is calculated from the voltage across the sampling resistor. The boundary condition calculation module performs reverse calculation of the environmental flow resistance based on the above real-time data. This module has a pre-stored fan operating characteristic model and... Under standard atmospheric pressure, unobstructed operation, and no natural wind, the system operates by traversing the three-dimensional manifold of duty cycle, reference speed, and reference current calibrated from 0% to 100% duty cycle. During system operation, the module reads the current drive duty cycle command issued to the fan and indexes the corresponding reference speed and reference current values ​​in the model. The module calculates the hydrodynamic residual between the real-time measured value and the reference value. The specific judgment logic is as follows: if the real-time speed feedback value is higher than the reference speed value and the bus current value is lower than the reference current value, it is determined that the current condition is a high vacuum condition with obstruction on the intake side; if the real-time speed feedback value is lower than the reference speed value and the bus current value is higher than the reference current value, it is determined that the current condition is an overload condition with backwind suppression on the exhaust side. A two-dimensional discrete flow resistance feature mapping table is constructed. Define the horizontal axis as the normalized speed deviation. The vertical axis represents the normalized current deviation. Grid resolution set to Locking in real-time operating points The four neighbor nodes in the mapping table Perform bilinear interpolation: ,in The normalized offset within the grid is used to calculate the result. Apply amplitude clamping logic to limit the output range ,in To prevent control divergence, a preset saturation threshold for the equivalent flow resistance coefficient is used. Based on the magnitude of this residual, the module generates a dimensionless equivalent flow resistance coefficient using a preset linear interpolation algorithm. The coefficient It intuitively represents the degree to which the current physical environment reduces heat dissipation efficiency.

[0022] The feedforward control correction module generates the final control command based on the aforementioned virtual thermal field and equivalent flow resistance coefficient. The module calculates the ideal base duty cycle required to maintain the target constant temperature using a PID control law, based on the peak heat value and average heat load in the virtual thermal field distribution data. Subsequently, the module introduces an equivalent flow resistance coefficient. Gain compensation is applied to this base value using the following formula: ,in, This is the drive duty cycle command that is ultimately output to the heat dissipation actuator; This is the base duty cycle calculated solely based on the virtual thermal field; The real-time equivalent flow resistance coefficient output by the boundary condition solution module; To compensate for the static frictional resistance of the cooling actuator, this correction process ensures that even when increased external wind resistance leads to a decrease in the flow rate of a single fan, the controller can automatically increase the drive voltage to maintain the match between the actual cooling flux and the predicted heat load, achieving adaptive immunity of the control command to environmental disturbances. The timing alignment control module is responsible for eliminating the phase lag caused by physical thermal inertia. This module obtains the physical response delay time required for the cooling system to accelerate from a standstill to effective airflow output, for example, 300ms to 500ms, and combines it with the frame queue depth of the video playback buffer to perform a leftward shift operation on the final drive command generated by the feedforward control correction module. That is, the system shifts the time axis to the left before the video stream frame data is sent to the LED light board driver chip for lighting. At any time, the heat dissipation command is sent to the fan drive circuit in advance, in which Equal to or slightly greater than the physical response delay time, this procedure ensures that the moment the cooling airflow reaches the PCB surface coincides with the Joule heat peak moment generated by the high-brightness LED screen, thereby suppressing junction temperature fluctuations to a very small range.

[0023] To ensure the engineering feasibility of the heat saturation arbitration and dynamic cooling capacity allocation mechanism, the system maintains a real-time dynamic heat budget equation, defining the current cooling capacity surplus. Maximum physical heat dissipation power of the heat dissipation actuator Compared with the current virtual thermal field total theoretical heat load The difference between them, i.e. ,in The environmental efficiency degradation factor is based on the current ambient temperature. When this occurs, the dynamic cooling distribution module is activated, locking video frames with grayscale values ​​higher than a preset highlight threshold. Calculate the area ratio of the pixel region. ,like If the value is less than the set local peak limit threshold, the module will... The amplitude generates an overclocking drive coefficient greater than 1.0. And apply it to the driving current of the highlighted area, so that ,in The rated current is used, while the junction temperature is continuously monitored by integration. The transient rate of change is used to ensure that it does not exceed the safety limit. When thermal saturation occurs, the thermal saturation arbitration module generates a pixel-level visual weight map based on the frequency domain features of the video frames. The system executes a reverse water injection algorithm based on this weighted graph, prioritizing the reduction of... The drive current in a low background or flat region remains until the condition is met again. The thermal balance constraint maximizes the retention of visual information under the hard boundary of limited physical heat dissipation capacity; the state correction module performs model benchmark calibration by utilizing the information gaps in the display process. The module continuously monitors video stream data. When it identifies a continuous black frame or a dark scene period where the overall gray value is lower than the preset threshold, it determines that there is no Joule thermal interference at this time and triggers the calibration action. The module collects the value of the NTC temperature sensor on the PCB board, identifies it as the current ambient reference temperature or the system heat accumulation baseline, and updates the zero-point parameters of the photothermal conversion model accordingly.

[0024] Example 1: In an LED display terminal application scenario deployed in an outdoor environment with strong convection and facing non-constant wind pressure interference, the terminal performs a high dynamic range (HDR) video stream display task. The screen undergoes a step change from a low grayscale dark field to a full white high-brightness screen. When the video stream frame data enters the system buffer queue, the virtual thermal field construction module analyzes the energy distribution state of each pixel in the high-brightness frame based on a preset photothermal conversion model and a nonlinear mapping table of current density and heating coefficient. For high grayscale pixels, the model matches a high heat dissipation coefficient according to the characteristics of the Drop curve and performs spatial domain operations using a preset-sized thermal diffusion convolution kernel to generate virtual thermal field distribution data representing the heat load distribution at future moments. The timing alignment control module identifies the physical response delay time required for the heat dissipation actuator to accelerate from a standstill to meet the heat load. The time was set to 450ms, and the time axis of the basic heat dissipation command calculated based on the virtual thermal field was shifted to the left, so that the drive signal appeared before the screen display. The system continuously sends commands to the drive circuit. Under conditions where there are reverse gusts of wind blowing directly onto the exhaust vents, causing aerodynamic back pressure in the heat dissipation channel, the execution status observation module synchronously collects real-time speed feedback values ​​at a frequency of 10Hz during the fan acceleration response command. With bus current value .

[0025] The boundary condition calculation module compares the real-time collected values ​​with the baseline speed values ​​recorded in the fan operation characteristic model under standard windless conditions. and reference current value A comparison was made to determine the real-time speed feedback value under headwind resistance. Below the reference speed value And bus current value Higher than the reference current value Under these conditions, the module determines that it is currently in an overload condition where the exhaust side is suppressed by the headwind, and calculates an equivalent flow resistance coefficient of 1.3 accordingly. The feedforward control correction module utilizes the equivalent flow resistance coefficient calculated in real time. For the ideal base duty cycle calculated solely based on the virtual thermal field Perform gain compensation calculations, following the formula. The controller outputs the corrected final drive duty cycle command. The amplitude of this instruction is higher than the base duty cycle. The drive fan motor outputs higher torque and speed to offset the flow reduction caused by the ambient back pressure. When the LED light panel is actually lit and generates a Joule heat peak, the actual cooling air flux in the heat dissipation channel reaches the expected thermal balance requirement value, suppressing the transient overshoot of the junction temperature. This collaborative control architecture transforms thermal management from a hysteretic response to temperature accumulation to an active management of energy flow and boundary constraints.

[0026] Example 2: This example aims to verify the adaptive disturbance suppression capability and thermal balance control effect of the aforementioned intelligent constant temperature heat dissipation and brightness collaborative control system for LED display terminals in a simulated outdoor unstructured fluid environment. The test platform was built in a constant temperature environment chamber equipped with a programmable wind tunnel. The base temperature of the environment chamber was set to 40.0℃ to simulate high-temperature conditions in summer. The test object was a P3.91 specification outdoor LED display module integrating the control system of this invention. A DC cooling fan with FG speed feedback function was installed on the back of the module. The wind tunnel outlet was directly opposite the module exhaust outlet to generate adjustable wind speed and wind pressure to simulate natural wind back pressure interference. The sampling period of the test system was set to 100ms. This parameter was determined based on the trade-off between Shannon's sampling theorem and the real-time performance of the control response. Considering the typical frequency range of the fan speed signal and the frequency domain characteristics of natural wind pressure changes, a sampling interval of 100ms is sufficient to capture the dynamic characteristics of flow resistance changes, while avoiding excessive computational load on the microcontroller. During the test, the display module continuously played a test video containing high-frequency black-and-white screen switching to generate violent thermal load fluctuations. At the same time, the control wind tunnel generated a series of step changes in reverse wind pressure, with the wind speed gradually increasing from 0m / s to 8m / s, with each step being 2m / s and each step lasting for 5 minutes.

[0027] After the test started, the system monitored and recorded the fan's drive duty cycle command, actual speed feedback, bus current, and PCB surface temperature of the LED module in real time. Data showed that in the baseline stage with no external headwind (wind speed of 0 m / s), the actual fan speed and the commanded duty cycle exhibited a good linear correlation, and the equivalent flow resistance coefficient... The fan speed stabilizes around 1.0, and the PCB surface temperature remains within the preset range of 55.0℃ to 58.0℃. When the wind tunnel is activated and a reverse wind speed of 4m / s is applied, the fan encounters back pressure, causing the actual fan speed to decrease by approximately 15% while maintaining the original duty cycle command. Simultaneously, the bus current increases by approximately 10%. At this point, the boundary condition calculation module quickly identifies this fluid dynamics residual and calculates... The value jumps to around 1.4, and then the feedforward control correction module responds. The change in value automatically increases the drive duty cycle command from the base value of 45% to 63%. To intuitively demonstrate the system's response characteristics to environmental disturbances, key data before and after the step change in wind speed during the test were selected for comparison, as shown in Table 1.

[0028] Table 1: Comparison of Key System Parameters Before and After a Step Change in Wind Speed

[0029] Referring to Table 1, as the reverse wind speed increases, the actual speed deviation shows a negative increasing trend, while the current deviation shows a positive increasing trend, indicating that the fan load increases, and the system's calculated equivalent flow resistance coefficient... The duty cycle then increases non-linearly, from 1.02 to 2.10, and correspondingly, the corrected final duty cycle... The airflow was increased to offset the reduction caused by flow resistance. It is worth noting that even under strong headwind conditions of 8.0 m / s, the steady-state temperature of the PCB board only increased slightly from 56.2℃ to 58.5℃, and never exceeded the safe threshold of 60.0℃.

[0030] Example 3: This example combines Figures 1 to 3 This document describes an intelligent constant temperature heat dissipation and brightness coordinated control system for an LED display terminal, as follows: Figure 1 As shown, the video stream frame data to be displayed serves as the source input, which is processed by the virtual thermal field construction module. This module is responsible for calculating the theoretical heat generation and performing spatial domain superposition to generate virtual thermal field distribution data. This data is then transmitted to the feedforward control correction module to generate basic commands. At the physical execution level, while the cooling actuator, i.e., the fan, is receiving drive commands and running, its physical operating status is monitored in real time by the execution status observation module. This module synchronously collects real-time speed feedback values ​​and drive circuit bus current values, and transmits these speed and current data to the boundary condition calculation module. The boundary condition calculation module calculates the equivalent flow resistance coefficient characterizing the environmental wind resistance based on the above-mentioned operating deviation, and feeds this coefficient back to the feedforward control correction module. The feedforward control correction module combines the virtual thermal field distribution data and the equivalent flow resistance coefficient, and generates the final drive command through gain compensation, which then acts on the cooling actuator to form a closed-loop control loop that can adapt to environmental disturbances.

[0031] like Figure 2 As shown, the horizontal axis of the chart represents time (seconds), and the vertical axis displays temperature (degrees Celsius, °C) and heat load (percentage, %). The chart contains three key curves: the bottom dashed line showing the heat load change indicates a step increase in system heat load between 0 and 0.5 seconds. The corresponding dashed line above, indicating no timing alignment control, shows that without a predictive mechanism, the system temperature lags behind the load change and overshoots, reaching a peak of 80°C and remaining there for 1.5 seconds before slowly decreasing. The solid line in the middle, indicating timing alignment control, shows that under the control strategy of this invention, the temperature response curve is smooth and without significant overshoot, and the steady-state temperature is effectively controlled at around 50°C. Figure 3 As shown, the timing logic begins with the video stream input. The video stream frame data is passed to the virtual thermal field construction module. This module sequentially executes the call to the photothermal conversion model, calculates the theoretical heat generation of pixels, and performs spatial domain superposition operations. Finally, it outputs the virtual thermal field distribution data to the feedforward control correction module. On the parallel physical feedback path, the data execution status observation module captures the data generated by the operation of the heat dissipation actuator, which are the real-time speed feedback value and the drive circuit bus current value. These operation status data are passed to the boundary condition solution module. The boundary condition solution module then queries the fan operation characteristic model, calculates the speed deviation and current deviation, solves the equivalent flow resistance coefficient, and outputs the equivalent flow resistance coefficient β to the feedforward control correction module. The feedforward control correction module combines the thermal field data from the virtual thermal field construction module and the coefficient β from the boundary condition solution module, generates basic heat dissipation control commands, performs gain compensation calculations, and finally outputs the final drive command to the heat dissipation actuator, thereby triggering a heat dissipation action that matches the current display screen and the ambient wind resistance.

[0032] Example 4: This example verifies the system's resource arbitration and dynamic allocation capabilities under extreme light and heat conditions. The test scenario is set to play an HDR test video that includes a dramatic transition between deep-sky starlight (low average brightness, high local peak brightness) and midday beach (high average brightness, full-screen high heat). In the deep-sky starlight scene, because a large area of ​​the screen is black, the total heat load calculated by the virtual thermal field is far lower than the rated capacity of the cooling system. The system calculates the surplus cooling capacity in real time. At this time, the dynamic cooling capacity allocation module intervenes, dynamically allocating the originally idle cooling and power supply quotas to the starlight dot matrix area, and automatically generating an overclocking drive command 1.25 times the rated value, causing the peak brightness of the starlight pixels to exceed the conventional physical limit, enhancing the dynamic contrast of the image. The visual impact was strong, and monitoring data showed that the average temperature of the PCB board only increased slightly by 0.8℃, still in the deep cold zone. The scene instantly switched to a midday beach scene, and the total heat load surged and instantly exceeded the maximum physical removal capacity of the heat dissipation system by about 15%. The heat saturation arbitration module was triggered. Based on frequency domain analysis, it was identified that the face of the person and the texture of the parasol in the scene were high-frequency, high-weight areas, while the flat areas of the sky and the beach were low-frequency, low-weight areas. The system automatically locked the drive current of the high-weight areas to remain unchanged, while performing a non-linear current decay operation on the low-weight areas. The test results showed that although the brightness of the background area decreased by about 18%, the brightness and details of the core human eye attention area were completely preserved, and the core temperature of the system was clamped within the safe warning line of 85℃.

[0033] Example 5: This example addresses the problem of invisible system thermal resistance and delayed fault prediction caused by the degradation of the physical performance of heat dissipation components after long-term operation of LED display terminals. To address the increased contact and convection thermal resistance caused by factors such as dried thermal grease, propagation of microcracks in heat pipes, or dust accumulation on heat sinks, an online health diagnosis mechanism based on thermal residual fingerprinting is constructed. This mechanism does not rely on additional physical sensors but utilizes the step signal inherent in the video stream, transitioning from a completely black frame to a bright frame, as an active thermal excitation. During system operation, when a brightness step change is detected in the video stream data, the virtual thermal field construction module instantly calls a preset photothermal conversion model and current environmental parameters to calculate the step excitation. The system obtains the theoretical temperature rise curve and simultaneously acquires the actual temperature rise curve fed back by the NTC temperature sensor at a high-frequency sampling rate. The system performs transient response analysis and compares the characteristic differences between the theoretical and actual temperature rise curves on the time axis. In the initial response stage dominated by heat capacity, if the rising slope of the actual temperature rise curve is lower than that of the theoretical curve and the lag time is shortened, it is determined that the heat capacity of the system has decreased. This corresponds to an increase in the contact thermal resistance between the heat sink and the heat source, such as the aging of thermal grease. If, in the steady state stage, the actual temperature value is higher than the theoretical prediction value and the deviation continues to increase over time, it is determined that the overall thermal resistance of the system has increased. This corresponds to a decrease in the convective heat transfer efficiency of the heat dissipation channel, such as dust accumulation and blockage.

[0034] The system extracts the above features as thermal residual fingerprints and compares them with a preset benchmark fingerprint database. This database stores the health status fingerprints of the device when it leaves the factory and typical fingerprint features under different aging conditions. Once the thermal residual fingerprint deviates from the benchmark range by more than a preset threshold, the system determines that the heat dissipation component has a declining health trend and generates a graded warning signal. For example, when the temperature rise deviation caused by the increase in thermal resistance exceeds 5°C, a first-level warning is triggered; when the deviation exceeds 10°C, a second-level warning is triggered and the maximum brightness output is automatically limited.

[0035] Example 6: This example addresses the control deviation problem caused by batch differences in heat dissipation components, assembly tolerances, and environmental baseline drift due to long-term operation. To this end, a reference manifold offline calibration method based on a controlled environment and an adaptive boundary condition calibration mechanism for field deployment are constructed. For the fan operating characteristic model, i.e., the construction of the three-dimensional data manifold of duty cycle-reference speed-reference current, the following controlled calibration process is executed: In a quiet wind test chamber with standard atmospheric pressure, a constant ambient temperature of 25±1℃, and no external airflow interference, the cooling fan to be calibrated is installed in a standard impedance test air duct. The test system inputs a PWM drive signal to the fan through a precision programmable power supply, and the duty cycle is linearly increased from 0% to 100% with a step size of 1%. At each duty cycle step point, after the fan speed stabilizes, the system synchronously records the FG feedback speed and bus current value. Each point is sampled 50 times continuously, and the arithmetic mean is taken as the reference data under this operating condition.

[0036] In response to initial environmental differences during on-site deployment, the system performs a power-on self-test and baseline calibration procedure. When the LED display terminal is powered on for the first time or restarted after maintenance, the system automatically enters the adaptive calibration mode. In this mode, the controller drives the cooling fan to run at a preset calibration duty cycle, such as 50%, until it reaches a steady state, and collects the current real-time speed and current values. The system compares the collected values ​​with the theoretical values ​​of the corresponding duty cycle in the aforementioned offline-built benchmark model, calculates the initial deviation, and if the initial deviation is within the preset reasonable tolerance range, the system determines it to be a static system error caused by minor differences in the current installation environment, such as slight differences in the cabinet structure or different initial air pressures, and generates a global correction factor to perform overall translation compensation on the benchmark model, establishing the zero flow resistance benchmark state of the current equipment in the current deployment environment. This mechanism ensures that the system can accurately perceive changes in dynamic environmental wind resistance with relative deviation under different physical conditions.

[0037] Example 7: This example aims to provide a system adaptive initialization procedure for pre-deployment in the field. After the LED display terminal is physically installed and powered on for the first time, it automatically establishes the zero flow resistance reference and thermal safety boundary in the current environment through a standardized self-test process. After the system is powered on, it enters a silent self-test state, shuts down all LED display units to eliminate photothermal interference, and the controller drives the cooling fan to operate step by step at a preset calibration duty cycle sequence. This sequence includes three duty cycle nodes: 20%, 50%, and 80%. At each duty cycle node, after the fan speed stabilizes, the system collects real-time feedback of the speed and bus current and compares them with the factory-preset fan operation characteristic model. By calculating the static deviation between the measured value and the theoretical reference value, the system generates a global correction factor to compensate for the fixed flow resistance error caused by installation back pressure, differences in cabinet airtightness, or changes in altitude and air pressure.

[0038] Next, the system performs a baseline scan of thermal characteristics. The controller illuminates the full-screen white field and maintains the maximum brightness output. At the same time, it continuously monitors the temperature rise curve of the NTC temperature sensor. The system records the rate of temperature change and time constant during the process from cold start to thermal steady state, and calibrates the heat capacity parameters and thermal resistance coefficient in the photothermal conversion model accordingly. If the measured temperature rise rate is higher than the theoretical prediction value, the system will automatically lower the upper limit threshold of the maximum allowable drive current and generate a derating protection strategy for the current heat dissipation environment.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. An intelligent constant-temperature heat dissipation and brightness coordination control system of an LED display terminal, characterized in that, Comprise: A virtual heat field construction module for receiving video stream frame data to be displayed, calling a preset light-heat conversion model to calculate the theoretical heat generation of each pixel point in the video stream frame data, and performing a spatial domain superposition operation on the theoretical heat generation to generate virtual heat field distribution data; An execution state observation module for synchronously collecting real-time speed feedback values of the heat dissipation execution mechanism and bus current values of the driving circuit during the operation of the heat dissipation execution mechanism in response to the driving instruction; A boundary condition solving module for calling a preset fan operation characteristic model to calculate the operation deviation of the real-time speed feedback value and the bus current value relative to the reference state, and solving the equivalent flow resistance coefficient representing the current environmental wind resistance according to the positive and negative polarity of the operation deviation; A feedforward control correction module for generating a basic heat dissipation control instruction according to the virtual heat field distribution data, and performing gain compensation on the basic heat dissipation control instruction using the equivalent flow resistance coefficient to generate a final driving instruction matched with the current environmental wind resistance to drive the heat dissipation execution mechanism; wherein the fan operation characteristic model records the corresponding relationship between different driving duty cycles and the reference speed and the reference current under standard ventilation impedance conditions; The feedforward control correction module compensates for the actual air volume attenuation caused by air inlet blockage or exhaust wind resistance by introducing the equivalent flow resistance coefficient.

2. The intelligent constant-temperature heat dissipation and brightness coordination control system of the LED display terminal according to claim 1, characterized in that, The boundary condition solving module is specifically configured to perform the following steps: querying the corresponding reference speed value and reference current value in the fan operation characteristic model according to the currently issued driving duty cycle instruction; calculating the speed deviation of the real-time speed feedback value and the reference speed value, and the current deviation of the bus current value and the reference current value; When the speed deviation is greater than the preset positive threshold and the current deviation is less than the preset negative threshold, it is determined that the current heat dissipation channel is in an air inlet blocked state, and an equivalent flow resistance coefficient greater than 1 is generated; when the speed deviation is less than the preset negative threshold and the current deviation is greater than the preset positive threshold, it is determined that the current heat dissipation channel is in an exhaust wind state, and an equivalent flow resistance coefficient greater than 1 is generated.

3. The intelligent constant-temperature heat dissipation and brightness coordination control system of the LED display terminal according to claim 1, characterized in that, The feedforward control correction module follows the following gain correction formula when generating the final driving instruction: wherein, Dout is the output duty ratio corresponding to the final driving instruction, Dbase is a basic duty ratio calculated only according to the virtual thermal field distribution data, R is the equivalent flow resistance coefficient output by the boundary condition solving module, S is a start compensation value used to offset the static friction resistance of the heat dissipation execution mechanism; the feedforward control correction module uses the formula to ensure that the effective air volume output by the heat dissipation execution mechanism matches the heat dissipation demand represented by the virtual thermal field distribution data under different wind resistance environments.

4. The intelligent constant-temperature heat dissipation and brightness coordination control system of the LED display terminal according to claim 1, characterized in that, Further comprising a timing alignment control module for establishing a light-heat response synchronization mechanism; the timing alignment control module acquires the response delay time of the heat dissipation execution mechanism, and performs time advance processing on the final driving instruction according to the response delay time to generate a preloaded driving instruction; the timing alignment control module issues the preloaded driving instruction to the heat dissipation execution mechanism to control the heat dissipation execution mechanism to start accelerating before the corresponding picture of the video stream frame data is displayed, so that the peak time of the heat dissipation air volume is synchronized with the arrival time of the heat generation peak of the LED lamp panel.

5. The intelligent constant-temperature heat dissipation and brightness coordination control system of the LED display terminal according to claim 1, characterized in that, Further comprising a heat saturation arbitration module for performing partition brightness adjustment when the heat dissipation capacity is insufficient; The thermal saturation arbitration module calculates the total heat load corresponding to the virtual thermal field distribution data in real time and compares the total heat load with the maximum heat dissipation power of the heat dissipation actuator. When the total heat load exceeds the maximum heat dissipation power, the thermal saturation arbitration module activates the non-uniform current adjustment mode. In the non-uniform current adjustment mode, the thermal saturation arbitration module generates a visual weight map based on the image frequency characteristics of the video stream frame data, and performs a priority reduction operation on the driving current of pixels in low-weight areas according to the visual weight map, until the corrected total heat load is not higher than the maximum heat dissipation power.

6. The intelligent constant-temperature heat dissipation and brightness coordination control system of the LED display terminal according to claim 5, characterized in that, When executing the non-uniform current regulation mode, the thermal saturation arbitration module is used to identify high-frequency texture regions and skin color regions in the video stream frame data and mark them as high-weight regions, while identifying low-frequency background regions and marking them as low-weight regions. The thermal saturation arbitration module maintains the drive current of the high-weight region unchanged and allocates the overflow portion of the total thermal load that exceeds the maximum heat dissipation power to the low-weight region for current reduction.

7. The intelligent constant-temperature heat dissipation and brightness coordination control system of the LED display terminal according to claim 1, characterized in that, It also includes a state correction module for performing baseline calibration during display idle periods; the state correction module monitors the grayscale data of video stream frame data and identifies idle periods of all-black frames or low grayscale frames; During idle periods, the state correction module collects temperature sensor values ​​at the LED light panel and uses these values ​​as the ambient reference temperature to correct the thermal calculation parameters of the photothermal conversion model.

8. The intelligent constant-temperature heat dissipation and brightness coordination control system of an LED display terminal according to claim 1, characterized in that, It also includes a thermal characteristic diagnostic module for monitoring the health status of the heat dissipation components. The thermal characteristic diagnostic module identifies the moment when brightness changes suddenly in the video stream frame data as the excitation start point and records the temperature change curve after the excitation start point. The thermal characteristic diagnostic module compares the temperature change curve with the theoretical temperature rise curve derived from the virtual thermal field distribution data, calculates the response time difference and steady-state temperature difference between the two, and generates a diagnostic signal for aging of the heat dissipation components or abnormal contact thermal resistance when the response time difference or steady-state temperature difference exceeds the preset range.

9. The intelligent constant-temperature heat dissipation and brightness coordination control system of an LED display terminal according to claim 1, characterized in that, It also includes a dynamic cooling capacity allocation module, which is used to improve local brightness by utilizing thermal capacity margin; the dynamic cooling capacity allocation module calculates the difference between the total heat load and the maximum heat dissipation power in real time as the heat dissipation margin at the current moment; the dynamic cooling capacity allocation module identifies local bright areas in the video stream frame data, and within the range allowed by the heat dissipation margin, generates a drive current command higher than the rated value to drive the local bright areas, and uses the transient thermal capacity of the system to absorb the additional heat generated.

10. The intelligent constant-temperature heat dissipation and brightness coordination control system of an LED display terminal according to claim 1, characterized in that, The photothermal conversion model includes a pre-set current-luminous efficacy characteristic table; the virtual thermal field construction module is used to analyze the proportion of input power converted into light energy and the proportion converted into heat energy in each pixel of the video stream frame data according to the current-luminous efficacy characteristic table. For low grayscale pixels, a high luminous efficacy coefficient is used to calculate heat energy, and for high grayscale pixels, a low luminous efficacy coefficient is used to calculate heat energy, so as to construct heat source distribution data that conforms to the physical characteristics of LED devices.

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