A light environment regulation system for plant factories based on photosynthesis simulation and spectral superposition

Abstract

This invention discloses a plant factory light environment control system based on photosynthetic simulation and spectral superposition, belonging to the field of smart agriculture technology. It addresses the shortcomings of existing light environment control systems that neglect the influence of the light-induced phase of photosynthesis on the photosynthetic rate and fail to consider the varying P values ​​under different environmental conditions during the dark reaction phase of photosynthesis. nmax This invention addresses the issue of differences in light saturation points. The system comprises: a data acquisition module, a control module, a full-spectrum light source regulation module, an execution module, a monitoring module, and a power supply module. The control module employs a two-stage control strategy: in the light-induction stage, by regulating the photosynthetically active radiation intensity and illumination time, the Fv / Fm ratio and stomatal conductance are controlled to reach normal values; in the dark reaction promotion stage, by constructing a regulation model, based on the collected CO2 concentration, temperature, photosynthetically active radiation intensity, and the achieved normal stomatal conductance value, the net photosynthetic rate is calculated, and the maximum net photosynthetic rate, light saturation point, and dark respiration rate are determined.

Description

Technical Field

[0001] This invention relates to the field of smart agriculture technology, and more specifically, to a plant factory light environment regulation system based on photosynthesis simulation and spectral superposition. Background Technology

[0002] Agriculture belongs to the primary industry, and its development is crucial to the national economy and people's livelihood. In recent years, my country's facility agriculture has gradually formed "smart agriculture," a component of the smart economy, driven by modern power electronics, computer, and Internet of Things technologies, during its modernization and digitalization process. Currently, plant factories and intelligent greenhouses, as important applications in the field of smart agriculture, have made significant progress in both laboratory innovation and commercial production in plant factories both domestically and internationally, thanks to the rapid development of modern information technology and sensor manufacturing capabilities. Light environment control, as a fundamental component of the intelligent control system of artificial light-based plant factories, improves crop growth and organic matter accumulation by regulating the power output level of the light source, thereby increasing yield and significantly positively impacting the economic benefits of plant factories.

[0003] Different crops exhibit varying physiological levels and habits; the same crop shows differences in growth and metabolic levels at different growth stages or within the same growth stage; and crop physiological indicators fluctuate with strongly correlated environmental variables under suitable growth conditions. Furthermore, crop responses in laboratory control generally exhibit lag. To address these issues, current research on laboratory-based plant factory environmental response control strategies primarily focuses on designing comparative experiments and determining the optimal points for various environmental parameters for quantitative control. These studies tend to use the light saturation point at the crop's maximum net photosynthetic rate as the control indicator. However, they suffer from several shortcomings, such as failing to develop control strategies from a mechanistic perspective (simulating the entire photosynthetic process), lacking comparative analysis of control results, and neglecting the impact of some adjustable physiological indicators on crop photosynthetic levels during environmental response. These issues require further investigation and improvement.

[0004] On the other hand, while artificial light environment control in facility agriculture is widely used in commercial production, practical innovation in the precise quantitative output of LED light sources lags behind. Generally, the design and optimization of light quality and control of daily cumulative illumination time are based on production experience. There is little exploration of the internal factors that lead to production conclusions such as increased economic benefits due to increased light intensity from the perspective of crop physiology. In the context of the rapid development of precision agriculture, the current unmanned control based on the empirical model of photosynthesis may involve a waste of production potential and energy consumption. Summary of the Invention

[0005] The technical problem to be solved by this invention is:

[0006] Existing light environment control systems neglect the impact of the light-induced phase of photosynthesis on the photosynthetic rate, and do not consider the P values ​​under different environmental conditions during the dark reaction phase of photosynthesis. nmax And the difference in light saturation point.

[0007] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0008] This invention provides a plant factory light environment regulation system based on photosynthetic simulation and spectral superposition, the system comprising:

[0009] The data acquisition module is used to collect environmental parameters of the plant factory, including CO2 concentration, temperature and photosynthetically active radiation (PAR), and send the collected environmental data to the control module and monitoring module.

[0010] The control module employs a two-stage control strategy, including a light-induced stage and a dark-reaction promotion stage for photosynthesis. In the light-induced stage, the photosynthetically active radiation intensity (PAR) and illumination time are adjusted to ensure that both Fv / Fm and stomatal conductance reach normal values; where Fv / Fm represents the maximum photochemical quantum yield of photosynthetic system II. In the dark-reaction promotion stage, a control model is constructed to calculate the net photosynthetic rate P based on the collected CO2 concentration, temperature, PAR, and the achieved normal stomatal conductance value. n Solve for the net photosynthetic rate P. n The extreme value is used to obtain the maximum net photosynthetic rate P. nmax Light saturation point I sat and dark respiration rate R d According to the light saturation point I sat The duty cycle of the driving signal is determined and sent to the full-spectrum light source control module, and the maximum net photosynthetic rate P is set. nmax Dark breathing rate R d and light saturation point I sat Send to the monitoring module;

[0011] The full-spectrum light source control module is used to amplify the received drive signal and send the amplified drive signal to the execution module.

[0012] The execution module includes an LED full-spectrum light source with tunable photon flux density (PPFD);

[0013] The monitoring module is used to receive CO2 concentration, temperature, and maximum net photosynthetic rate P. nmax Dark breathing rate R d and light saturation point I sat To monitor environmental parameters;

[0014] The power supply module is used to provide electrical energy to the system.

[0015] Furthermore, the data acquisition module includes multiple acquisition units, each of which includes a CO2 concentration sensor, a temperature sensor, and a photosynthetically active radiation intensity sensor. The execution module is equipped with an actuator corresponding to the acquisition unit, and each actuator includes an LED light source with adjustable photon flux density (PPFD).

[0016] Furthermore, in the light-induced stage, by collecting the Fv / Fm and stomatal conductance values ​​of the crop under different gradients of photosynthetically active radiation intensity and illumination time, the photosynthetically active radiation intensity and illumination time that both Fv / Fm and stomatal conductance reach normal values ​​are obtained, so as to control Fv / Fm and stomatal conductance to reach normal values ​​by adjusting the photosynthetically active radiation intensity and illumination time.

[0017] Furthermore, for leafy vegetables, the photosynthetically active radiation intensity during the light-induced phase is greater than or equal to 800 μmol·m⁻¹. -2 .s -1 The illumination time is greater than or equal to 20 minutes.

[0018] Furthermore, the calculation formula upon which the regulation model is based is:

[0019]

[0020] Based on the collected CO2 concentration, temperature, photosynthetically active radiation (PAR), and the normal value of stomatal conductance, the net photosynthetic rate P was calculated. n ;

[0021] The net photosynthetic rate P is solved based on a modified right-angle hyperbola model. n The extreme value is used to obtain the maximum net photosynthetic rate P. nmax Light saturation point I sat and dark respiration rate R d ,Right now:

[0022]

[0023]

[0024]

[0025]

[0026] Where, x PAR y Tair , u Cond The values ​​are, in order, the effective radiation intensity of photosynthesis, temperature, carbon dioxide concentration, and stomatal conductance. b0~b9, c1~c9, and d1~d8 are all parameters of the model. α, β, and γ are dimensionless parameters of the rectangular hyperbola modified model.

[0027] Furthermore, the power of the LED full-spectrum light source with tunable photon flux density (PPFD) is not less than 300W.

[0028] Furthermore, the plant factory light environment control system also includes a spectral control module. The spectral control module is used to adjust the spectrum to the natural spectrum based on the principle of spectral superposition. The spectral control module includes multiple output light sources, each consisting of multiple matrix-arranged LED units. The spectral band coverage of the multiple output light sources is 380-700nm. Spectral control is achieved by adjusting the spectral radiation intensity of the LED units corresponding to the natural spectrum wavelengths to match the radiation intensity of the natural spectrum.

[0029] Furthermore, the number of LED units in the multi-output light source is greater than 18, and the difference between the peaks of each LED unit is greater than or equal to 15nm. The full width at half maximum (FWHM) of each LED unit is not greater than 20nm. Each LED unit includes the same number of LED beads of the same specification connected in series.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] This invention establishes a plant factory light environment regulation system based on photosynthetic simulation and spectral superposition. It is based on the light-induction and dark reaction stages of plant photosynthesis. In the light-induction stage, the system controls both Fv / Fm and stomatal conductance to normal values ​​by considering the synergistic effect of stomatal conductance and environmental parameters on the photosynthetic level. In the dark reaction stage, the system adjusts the net photosynthetic rate P during the dark reaction stage based on the maximum floating net photosynthetic rate and corresponding light saturation point under the current environment. n By implementing regulation, abnormal growth states such as light stress and high-level photorespiration that may occur due to a large difference between the predicted and actual values ​​of the crop's current light saturation point by the regulation platform can be avoided.

[0032] The present invention also includes a strategy for regulating the spectral distribution, which improves the level of organic matter accumulation at the crop photoreceptor level and can meet the needs of different crops or the same crop at different growth stages for the optimal spectral distribution of the light environment. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the regulation strategy of the plant factory light environment regulation system based on photosynthetic simulation and spectral superposition in an embodiment of the present invention;

[0034] Figure 2 This illustrates the interaction between the various modules of the control platform in this embodiment of the invention.

[0035] Figure 3This is the regression-standardized residual distribution histogram in this embodiment of the invention;

[0036] Figure 4 This is the standardized residual normal PP plot in the embodiments of the present invention;

[0037] Figure 5 This describes the hardware structure of the control platform in this embodiment of the invention.

[0038] Figure 6 This is a schematic diagram of the control platform and sensor deployment in an embodiment of the present invention. Detailed Implementation

[0039] In the description of this invention, it should be noted that the terms "first," "second," and "third" mentioned in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," and "third" may explicitly or implicitly include one or more of that feature.

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0041] Specific Implementation Plan 1: Combining Figures 1 to 2 As shown, this invention provides a plant factory light environment control system based on photosynthetic simulation and spectral superposition. The system includes:

[0042] The data acquisition module is used to collect environmental parameters of the plant factory, including CO2 concentration, temperature and photosynthetically active radiation (PAR), and send the collected environmental data to the control module and monitoring module.

[0043] The control module employs a two-stage control strategy, including a light-induced stage and a dark-reaction promotion stage for photosynthesis. In the light-induced stage, the photosynthetically active radiation intensity (PAR) and illumination time are adjusted to ensure that both Fv / Fm and stomatal conductance reach normal values; where Fv / Fm represents the maximum photochemical quantum yield of photosynthetic system II. In the dark-reaction promotion stage, a control model is constructed to calculate the net photosynthetic rate P based on the collected CO2 concentration, temperature, PAR, and the achieved normal stomatal conductance value. n Solve for the net photosynthetic rate P. n The extreme value is used to obtain the maximum net photosynthetic rate P. nmax Light saturation point I sat and dark respiration rate R d According to the light saturation point I sat The duty cycle of the driving signal is determined and sent to the full-spectrum light source control module, and the maximum net photosynthetic rate P is set.nmax Dark breathing rate R d and light saturation point I sat Send to the monitoring module;

[0044] The full-spectrum light source control module is used to amplify the received drive signal and send the amplified drive signal to the execution module.

[0045] The execution module includes an LED full-spectrum light source with tunable photon flux density (PPFD);

[0046] The monitoring module is used to receive CO2 concentration, temperature, and maximum net photosynthetic rate P. nmax Dark breathing rate R d and light saturation point I sat To monitor environmental parameters;

[0047] The power supply module is used to provide electrical energy to the system.

[0048] The full-spectrum light source control module described in this embodiment comprises three parts: a signal amplification stage, a step-down stage, and a high-power LED dimming power supply. The signal amplification stage increases the gain of the drive signal output by various microcontrollers in the control module to meet the amplitude requirements of the PWM modulation of the LED dimming power supply. The step-down stage is connected between the power supply module and the signal amplification stage. This stage selects a suitable DC-DC step-down module based on the actual gain requirements of the signal amplification stage. In other words, the gain result of the signal amplification stage on the output signal of the control module is determined by this stage. The high-power LED dimming power supply must support PWM dimming.

[0049] The power supply module adopts a photovoltaic-battery inverter structure modulated by SPWM method combined with the mains power supply scheme to power the operation of the control module, full-spectrum light source control module, execution module, monitoring module and spectrum control module.

[0050] In this implementation scheme, the dark reaction promotion stage of photosynthesis is achieved by predicting the current P of the crop under suitable growth conditions. n and the maximum achievable net photosynthetic rate point (P nmax ) and corresponding light saturation point (I sat ), improve P n Make it close to P nmax Increasing crop carbon assimilation levels promotes the accumulation of plant dry matter, thereby increasing yield.

[0051] This invention formulates control strategies targeting the two-stage reaction characteristics of photosynthesis, and uses mathematical models to simulate the light response of the two stages of photosynthesis, further optimizing crop carbon assimilation levels. Based on the characteristics of the light-induction stage and the dark reaction stage of plant photosynthesis, this invention provides substrate and ATP for the dark reaction stage after fixing light energy under light conditions, given the short light-induction stage. The light-induction stage provides timely light to the plant at the unsaturated point PAR, which simultaneously satisfies the requirement of maximizing the photochemical quantum yield (Fv / Fm) of PS II in the crop's chlorophyll fluorescence parameters and ensuring that stomatal conductance is close to normal levels. This allows different crops to adapt daily from a dark environment to a light environment to begin photosynthesis. The dark reaction stage is a slow enzymatic reaction that occurs in the chloroplast stroma and does not require photosynthetic pigments or light catalysis, but the production of its reaction enzymes depends on light. When regulating the light environment for different crops, the control model varies dimensionlessly, and the P values ​​of different crops or the same crop under different environmental gradients change accordingly. nmax And the corresponding light saturation points differ, that is, the P that the crop can currently achieve. nmax Or it may be fluctuating, changing significantly with fluctuations in environmental parameters. Therefore, the control model in this implementation plan is based on periodic monitoring data within the plant factory to achieve plant fluctuation P. nmax Adaptive regulation is implemented. To avoid optical stress, the correlation between the predicted optical saturation point and the duty cycle of the driving signal is determined by selecting extreme points to improve prediction accuracy and avoid energy waste and stress caused by oversaturated PAR.

[0052] Specific Implementation Scheme Two: The data acquisition module includes multiple data collectors, each including a CO2 concentration sensor, a temperature sensor, and a photosynthetically active radiation intensity sensor. The execution module is equipped with actuators corresponding to the data collectors, each actuator including an LED light source with adjustable photonic quantum flux density (PPFD). This implementation scheme is otherwise identical to Specific Implementation Scheme One.

[0053] Specific Implementation Scheme Three: In the light induction stage, Fv / Fm and stomatal conductance values ​​are collected from crops at different gradients of photosynthetically active radiation intensity and illumination time. This yields photosynthetically active radiation intensity and illumination time where both Fv / Fm and stomatal conductance reach normal values. By adjusting the photosynthetically active radiation intensity and illumination time, Fv / Fm and stomatal conductance can be controlled to reach normal values. All other aspects of this implementation scheme are the same as in Specific Implementation Scheme One.

[0054] Specific Implementation Plan Four: For leafy vegetables, the photosynthetically active radiation intensity during the light-induced phase is greater than or equal to 800 μmol·m⁻¹. -2 .s -1 The illumination time is greater than or equal to 20 minutes. All other aspects of this implementation plan are the same as those in Specific Implementation Plan Three.

[0055] 9. Specific Implementation Plan Five: The calculation formula upon which the regulation model is based is:

[0056]

[0057] Based on the collected CO2 concentration, temperature, photosynthetically active radiation (PAR), and the normal value of stomatal conductance, the net photosynthetic rate P was calculated. n ;

[0058] The net photosynthetic rate P is solved based on a modified right-angle hyperbola model. n The extreme value is used to obtain the maximum net photosynthetic rate P. nmax Light saturation point I sat and dark respiration rate R d ,Right now:

[0059]

[0060]

[0061]

[0062]

[0063] Where, x PAR y Tair , u Cond The parameters are, in order, the effective radiation intensity for photosynthesis, temperature, carbon dioxide concentration, and stomatal conductance. b0~b9, c1~c9, and d1~d8 are parameters of the model, and α, β, and γ are dimensionless parameters of the rectangular hyperbolic modified model. All other aspects of this implementation scheme are the same as in specific implementation scheme one.

[0064] In this implementation scheme, by (P) n -I-CO2-Tg s The model (Equation 1) and the modified rectangular hyperbola model (Equation 2) are combined to predict the current photosynthetic rate P of the crop. n Maximum net photosynthetic rate P nmax and the corresponding light saturation value I sat By sending control signals, the photosynthetically active radiation intensity (PAR) of the crop is made equal to the light saturation value (I). sat To improve P n Make it close to P nmax .

[0065] Specifically, the dark reaction of photosynthesis, also known as the Calvin cycle, is a process that does not directly rely on photocatalysis or light energy conversion; the generation of its energy-supplying substances and reaction substrates depends on the light source. Therefore, this implementation scheme is based on the predicted net photosynthetic rate level and P... nmaxBy controlling the light environment corresponding to the light saturation point and the crop growth environment, the photosynthetic level of crops can be improved. First, the P shown in formula (1) of the regulation model is constructed. n -I-CO2-Tg s The model, by setting different gradient values ​​for temperature, carbon dioxide concentration, and photosynthetically active radiation (PAR), measures the net photosynthetic rate of plants and fits the model to obtain specific parameters to simulate the Calvin cycle of photosynthesis. Then, it collects four sets of data on temperature, carbon dioxide concentration, PAR, and the obtained normal values ​​for stomatal conductance. Existing research suggests that P... n With g s Or there exists a linear positive correlation, at which point g s As a constant, take the corresponding P nmax g smax Then (P) n -I-CO2-Tg s The model can be transformed into one with g. s constant (P) n -I-CO2-T) model, i.e.

[0066]

[0067] By substituting environmental parameters collected four times into a system with g s constant (P) n The -I-CO2-T model yields P ni (i = 1, 2, 3, 4), and simultaneously, construct the four-dimensional full-rank matrix of formula (3) by combining the rectangular hyperbola correction model as shown in formula (2), and solve for the dimensionless α, β, γ and crop dark respiration rate R of the rectangular hyperbola correction model. d Unit: μmol(CO2)·m -2 ·s -1 Finally, based on formulas (4) and (5), the P that the crop can achieve under suitable floating environment conditions is predicted. nmax and corresponding light saturation point I sat .

[0068] The right-angle hyperbolic correction model reflects the effect of light environment on crop P n The actual values ​​of α, β, and γ depend on the sample data, meaning that changes in these three correction coefficients are affected by significant fluctuations in data correspondence or other environmental parameters. Four data collections constitute one prediction cycle, which is relatively short (9 minutes), during which CO2 concentration, temperature, and other environmental variables within the plant factory do not fluctuate significantly. Furthermore, sufficient time is allocated in the light induction phase to improve crop F... v / F mStomatal conductance. If the crop is in an outdoor environment or other environment where there is frequent gas exchange with the outside world or drastic environmental changes, the two equations are not linked, and the control strategy is not applicable.

[0069] This implementation plan is based on I sat The predicted value determines the duty cycle of the pulse width modulation output signal. The correspondence between the duty cycle and the output PAR of the light source is as follows:

[0070] g(I sat DutyRatio pwm (7)

[0071] When the light source PAR equals I sat Maintain this output level for at least 20 minutes to avoid P due to the photoresponse hysteresis of the porosity. n With P nmax The difference is significant.

[0072] Specific Implementation Scheme Six: The power of the LED full-spectrum light source with adjustable photonic quantum flux density (PPFD) is not less than 300W. All other aspects of this implementation scheme are the same as Specific Implementation Scheme One.

[0073] Specific Implementation Scheme Seven: The plant factory light environment control system further includes a spectral control module. This module, based on the principle of spectral superposition, is used to adjust the spectrum to match the natural spectrum. The spectral control module includes multiple output light sources, each comprising multiple matrix-arranged LED units. The spectral band coverage of the multiple output light sources is 380-700 nm. Spectral control is achieved by adjusting the spectral radiation intensity of the LED units corresponding to the natural spectrum wavelengths to match the natural spectrum intensity. Other aspects of this implementation scheme are the same as in Specific Implementation Scheme One.

[0074] The theoretical basis of the spectral modulation module in this implementation scheme is: to determine the spectral radiant intensity of LED light-emitting units at different peak wavelengths using an existing Gaussian distribution function, which is:

[0075] L λ =αI·exp[-2(λ-λ) c ) 2 / ω 2 (8)

[0076] Where L λ Let α be the spectral radiance of a single LED along the optical axis, α be the conversion coefficient between the output drive current of the execution module and the spectral radiance (α can be considered a constant when the LED is of a fixed type), I be the drive current, and λ be the spectral radiance. c The peak wavelength of each LED light-emitting unit in the radiation intensity distribution can be approximated as a constant.

[0077] L(λ)=∑K i S i (λ) (9)

[0078] Where S i (λ) is the spectral distribution of a single LED light-emitting unit when the driving current reaches the rated value, K i Given an unknown coefficient matrix, after selecting the target spectrum, it is necessary to select the corresponding K. i The coefficient improves the fitting accuracy of the tunable spectral LED light source to the target spectrum. The spectral control strategy is based on the principle of spectral superposition, using the natural spectrum as the target spectrum. The spectral control module outputs PWM signals, and the duty cycle of each signal determines the spectral radiation intensity of the light-emitting unit. The PWM signal drives the current of the full-spectrum light source control module to change according to the duty cycle, thereby adjusting the spectral radiation intensity of each light-emitting unit (divided by different peaks) in the tunable spectral LED light source to obtain the target spectral distribution.

[0079] Specific Implementation Scheme 8: The number of LED units in the multi-output light source is greater than 18, and the difference between the peaks of each LED unit is greater than or equal to 15nm. The full width at half maximum (FWHM) of each LED unit is no greater than 20nm. Each LED unit includes multiple LED beads of the same specification connected in series. All other aspects of this implementation scheme are the same as in Specific Implementation Scheme 7.

[0080] Example 1

[0081] like Figure 5 As shown, the Loongson 1B development board is selected as the core of the control unit. Data transmission and reception with the host computer and monitoring module are achieved through the serial ports on the board via RS232 and RS485 interfaces. A pair of MEAN WELL ELG-240 series LED dimmers, a YF-44 signal amplification module, and an LM2596S step-down module are selected to form the spectrum control module. The monitoring module can be connected to the cloud platform using the Shandong Youren Cloud WHNB75-BA industrial-grade NB-IoT module to complete the periodic monitoring of the current growth environment and some physiological indicators of crops on the cloud platform of the domestic plant factory light environment control platform. The arrangement of each sensor is as follows. Figure 6 As shown.

[0082] like Figure 6As shown, hydroponically grown glass lettuce was used as the experimental subject. The experiment lasted for three harvest periods. Ten lettuce plants with similar growth (fresh weight of 90-140g) were selected from days 10-15 of the transplanting period in each harvest period. During these 10-15 days, gradient values ​​were set for temperature, carbon dioxide concentration, and photosynthetically active radiation (PAR) in the canopy leaves within the photosynthetic air chamber. The ion concentration ratio of the nutrient solution was the same for all harvest periods, as shown in Table 1. Each crop received 12 hours of cumulative daily light. The PAR output range in the Li-6400 leaf chamber was controlled between 200 and 1600 μmol·m⁻¹. -2 ·s -1 Within this range, the step size is 100 μmol·m -2 ·s -1 The spectral band of the light source output from the leaf chamber is distributed between 380 and 780 nm. The temperature of the leaf blade sandwiched in the leaf chamber is maintained between 15 and 27°C, corresponding to a temperature acquisition step size of 1°C in the experimental data. The CO2 concentration is controlled between 300 and 1700 ppm, corresponding to a data acquisition step size of 200 ppm.

[0083] Table 1

[0084]

[0085] At each planting period, the net photosynthetic rate of the canopy leaves of 10 hydroponic glass lettuce plants was measured by changing the environmental parameters in the air-clamping chamber of the Li-6400 photosynthesis monitoring instrument. 1560 sets of valid data were retained (4680 sets in total for the three harvest periods), and the data were processed.

[0086] The collected data were fitted using nonlinear regression to obtain the control model shown in formula (1), i.e., P n -I-CO2-Tg s The parameters of the model, namely:

[0087]

[0088] The model's fit R 2 The value is 0.899, indicating a good fit.

[0089] Significance analysis was performed on the model variables and outputs, and the results are as follows:

[0090] Table 2

[0091]

[0092]

[0093] Table 2 shows that the significance levels for Tair, PARi, Cond, and Ca are all less than 0.05. Figure 3 and Figure 4 As shown, the residuals are uniformly distributed near the normal curve, indicating that the input variables of the control model of this invention have a significant impact on the net photosynthetic rate.

[0094] The LED unit in the spectral control module uses packaged semiconductor lamp beads with 18 to 28 different peak wavelengths and a full width at half maximum (FWHM) of no more than 20 nm. These are arranged in a matrix and embedded on a substrate to form a single light-emitting unit. Each light-emitting unit is independent and fixed in a matrix arrangement within the light source frame. The lamp beads with different peak wavelengths within each individual light-emitting unit are not connected to each other. Each LED unit uses lamp beads of the same specification on the same branch. Each branch receives a corresponding drive signal from the lower-level machine to change the spectral distribution of that LED unit. Based on the principle of spectral superposition, the lower-level machine sends multiple (18-28) control signals and amplifies them. By controlling the high-power drive power supply, the spectral adjustment of the LED light source is achieved. The multi-channel integrated structure of the adjustable spectral light source can meet the different needs of crops for the spectral distribution of artificial light sources at different stages during the planting period.

[0095] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A plant factory light environment regulation system based on photosynthesis simulation and spectral superposition, characterized in that, The system comprises: a data acquisition module for acquiring environmental parameters of the plant factory, including CO2 concentration, temperature and photosynthetically active radiation intensity (PAR), and sending the acquired environmental data to the control module and the monitoring module; The control module adopts a two-stage control strategy, including a light induction stage and a photosynthesis dark reaction promotion stage. In the light induction stage, the Fv / Fm and the stomatal conductance are controlled to reach normal values by regulating the photosynthetically active radiation intensity and the illumination time. The Fv / Fm is the maximum photochemical quantum yield of photosystem II. In the photosynthesis dark reaction promotion stage, a regulation model is constructed, and based on the collected CO2 concentration, temperature, photosynthetically active radiation intensity (PAR), and the achieved normal value of the stomatal conductance, the net photosynthetic rate P n is calculated. The extreme value of the net photosynthetic rate P n is solved to obtain the maximum net photosynthetic rate P nmax , the light saturation point I sat , and the dark respiration rate R d . The duty cycle of the driving signal is determined according to the light saturation point I sat , is sent to the full-spectrum light source regulation module, and the maximum net photosynthetic rate P nmax , the dark respiration rate R d , and the light saturation point I sat are sent to the monitoring module. a full-spectrum light source regulation module for amplifying the received driving signal and sending the amplified driving signal to the execution module; an execution module comprising a light quantum flux density (PPFD) adjustable LED full-spectrum light source; a monitoring module for receiving CO2 concentration, temperature, maximum net photosynthetic rate P nmax , dark respiration rate R d and light saturation point I sat， for monitoring environmental parameters; a power supply module for providing power to the system; The calculation formula based on the regulation model is: Based on the collected CO2 concentration, temperature and photosynthetically active radiation intensity (PAR) and the achieved normal value of stomatal conductance, the net photosynthetic rate P is calculated n； Based on the modified rectangular hyperbolic model to solve the net photosynthetic rate P n The maximum net photosynthetic rate P nmax , light saturation point I sat and dark respiration rate R d， , that is: wherein, The parameters are in turn the photosynthetically active radiation intensity, temperature, carbon dioxide concentration and stomatal conductance, b0~b9, c1~c9, d1~d8 are parameters of the model, and α, β and γ are dimensionless for the hyperbolic correction model.

2. The plant factory light environment regulation system based on photosynthesis simulation and spectral superposition according to claim 1, characterized in that, The data acquisition module comprises a plurality of collectors, each collector comprising a CO2 concentration sensor, a temperature sensor and a photosynthetically active radiation intensity sensor, and the execution module is provided with an executor corresponding to the collector, each executor comprising a light quantum flux density (PPFD) adjustable LED light source.

3. The plant factory light environment regulation system based on photosynthesis simulation and spectral superposition according to claim 1, characterized in that, In the light induction stage, the Fv / Fm and stomatal conductance values under different gradients of photosynthetically active radiation intensity and illumination time are collected to obtain the photosynthetically active radiation intensity and illumination time at which the Fv / Fm and stomatal conductance values reach normal values, so as to control the Fv / Fm and stomatal conductance values to reach normal values by regulating the photosynthetically active radiation intensity and illumination time.

4. The plant factory light environment regulation system based on photosynthesis simulation and spectral superposition according to claim 3, characterized in that, For leafy vegetables, the light-induced phase has a photosynthetically active radiation intensity greater than or equal to 800 μmol.m -2 .s -1 for a light exposure time greater than or equal to 20 min.

5. The plant factory light environment regulation system based on photosynthesis simulation and spectral superposition according to claim 1, characterized in that, The power of the light quantum flux density (PPFD) adjustable LED full-spectrum light source is not less than 300W.

6. The plant factory light environment regulation system based on photosynthesis simulation and spectral superposition according to claim 1, characterized in that, The plant factory light environment regulation system further comprises a spectrum regulation module based on the spectrum superposition principle for regulating the spectrum to the natural spectrum, the spectrum regulation module comprising a multi-output light source, the multi-output light source comprising a plurality of matrix-arranged LED units, the multi-output light source having a spectrum band coverage range of 380-700nm; by adjusting the spectrum radiation intensity of the LED units corresponding to the wavelength of the natural spectrum to the same as the radiation intensity of the natural spectrum, the spectrum regulation is realized.

7. The plant factory light environment regulation system based on photosynthesis simulation and spectral superposition according to claim 6, characterized in that, The number of LED units in the multi-output light source is greater than 18, the difference between the wave peaks of each LED unit is greater than or equal to 15nm, the full width at half maximum of each LED unit is not greater than 20nm, and each LED unit comprises a plurality of serially connected LED lamp beads of the same specification.

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