Solar street lamp lithium battery intelligent charge-discharge control system

Abstract

The application discloses a kind of solar street lamp lithium battery intelligent charge-discharge control systems, it is related to lithium battery intelligent charge-discharge control technical field.The solar street lamp lithium battery intelligent charge-discharge control system includes: biological characteristic signal quality monitoring module;Lithium battery temperature-resistance coupling monitoring module;Output power-load adaptability monitoring module;Solar street lamp control stability monitoring module.The application is analyzed by lithium battery temperature-resistance coupling to determine whether to take charge-discharge threshold dynamic regulation, secondly based on output power-load adaptability monitoring result to determine whether to take discharge power self-adapting adjustment, finally solar street lamp control stability evaluation is carried out, based on solar street lamp control stability evaluation result to determine whether to take multi-stage protection coordination optimization, reach the effect of improving lithium battery intelligent charge-discharge control stability, solve the problem of low lithium battery intelligent charge-discharge control stability in prior art.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of intelligent charging and discharging control of lithium batteries, in particular to a lithium battery intelligent charging and discharging control system for solar street lamps. BACKGROUND

[0002] In the daily operation of a solar street lamp, first, a solar cell panel absorbs external light and converts it into electrical energy. After being processed by a rectification and filtering circuit inside a charging and discharging control center, the electrical energy is converted into direct current suitable for lithium batteries. At this time, the charging and discharging control center will detect the current power, voltage and temperature of the lithium battery in real time. If the battery is not fully charged and the environmental parameters are normal, the charging program will be started. Then, the charging and discharging control center will dynamically adjust the charging current according to the battery power during the charging stage, while continuously monitoring the battery temperature. If the temperature is too high, the charging current will be automatically reduced or the charging will be suspended, and the charging and discharging control system is equipped with a coupling abnormality counter, a delay confirmation timer and the like. When the light intensity decreases to a set threshold in the evening, the charging and discharging control center will automatically switch to the discharging mode, stably outputting the electrical energy stored in the lithium battery to the solar load street lamp light source, such as an LED (Light Emitting Diode) lamp, and still monitoring the battery voltage in real time. If the voltage is lower than the protection threshold, the discharging circuit will be automatically cut off to prevent over-discharge. After the light recovers the next day, the charging cycle will be entered again.

[0003] In the process of lithium battery capacity detection and electrical energy recovery of a solar street lamp, the prior art first acquires the voltage, current and other core state parameters of the lithium battery in real time through an operational amplifier circuit. Then, the charging and discharging control center analyzes and judges the current state of the battery according to the acquired core state parameters, determines whether the battery needs to be charged to supplement electrical energy or needs to be discharged for capacity testing, and then sends corresponding charging and discharging control instructions to a MOS (Metal-Oxide-Semiconductor Field-Effect Transistor) tube driving module. After that, the MOS tube receives the instructions and responds quickly, and drives the MPPT (Maximum Power Point Tracking) charging and discharging control circuit to start running. The circuit will efficiently adjust the electrical energy according to the instruction requirements. If it is a discharging control (such as a capacity testing scene), the electrical energy output by the battery will be converted into a form suitable for the electrical energy recovery battery. Finally, the electrical energy adjusted by the MPPT charging and discharging control circuit is no longer consumed by the load, but is stably transmitted to the electrical energy recovery battery for storage, while the charging and discharging control center continuously monitors the battery state through the operational amplifier circuit.

[0004] For example, the disclosure number: CN115811115A of Chinese invention patent application discloses a kind of solar street lamp automatic power reduction circuit, including: first, the charging and discharging current of lithium battery pack is collected in real time by resistance R1 and chip U1 in sampling circuit, while control circuit directly monitors the terminal voltage of lithium battery pack;Next, control circuit is based on the voltage and current signal collected, real-time calculation and accumulation lithium battery pack charging capacity Q1 and discharge capacity Q2, when judging discharge capacity Q2 exceeds charging capacity Q1 reaches preset threshold, control circuit automatically cuts off the connection between its execution end and load, to realize the automatic power reduction operation of solar street lamp.

[0005] For example, the disclosure number: CN107026498B of Chinese invention patent discloses lithium electric photovoltaic module and solar cell street lamp with it, including: first, under the condition of daylight, solar cell panel at the top of lithium electric photovoltaic module starts to capture sunlight and efficiently converts it into electric energy;Next, intelligent charging and discharging management circuit starts core work, on the one hand, the generated electric energy is preferentially charged to the lithium battery which is integrally packaged with photovoltaic panel and highly integrated, and is stored, and on the other hand, through precise heat dissipation and thermal management design (such as using metal substrate heat conduction), the battery is maintained at a suitable temperature to avoid overcharging and overdischarging;Then, when the ambient light weakens to night or cloudy day level, the light control sensing module will automatically trigger, and the control circuit will switch to discharging mode immediately, at this time, the electric energy stored in the lithium battery is stably released to drive the high-efficiency LED street lamp to emit light, realizing full-automatic lighting without attendance.

[0006] It is found that the above-mentioned technology at least has the following technical problems:

[0007] In the application scenario of outdoor solar street lamp in winter low temperature, when lithium battery intelligent charging and discharging control is carried out, since the existing charging and discharging control mostly adopts fixed charging and discharging parameter model based on normal temperature calibration, only the fixed internal resistance parameter at normal temperature is used to calculate the charging and discharging threshold, and the lithium battery internal resistance dynamic compensation logic is not designed for low temperature environment, which may cause the charging and discharging control circuit to misjudge the charging and discharging capacity of lithium battery. Since the lithium battery charging and discharging capacity is misjudged, the output current is still controlled according to the output current threshold at normal temperature in the discharging stage, so that the output current cannot be dynamically lowered according to the increased internal resistance at low temperature, and since the lithium battery internal resistance significantly increases at low temperature, the actual output current is limited by internal resistance and cannot reach the rated current required by solar load light source under the control of fixed current threshold, so that the actual output power of lithium battery is lower than the rated demand of solar load light source (such as LED lamp), which finally causes the solar street lamp to appear frequent flicker or power failure in the middle of the night, and the stability of lithium battery intelligent charging and discharging control is low. SUMMARY

[0008] In order to solve the technical problem of low stability of intelligent charge-discharge control of lithium battery in the prior art, the embodiment of the present application provides a lithium battery intelligent charge-discharge control system for solar street lamps, comprising: a lithium battery temperature-internal resistance coupling monitoring module, an output power-load adaptability monitoring module and a solar street lamp control stability monitoring module; wherein the lithium battery temperature-internal resistance coupling monitoring module is used for lithium battery temperature-internal resistance coupling analysis for ensuring the safety of lithium battery charge-discharge during the process of lithium battery intelligent charge-discharge control, and based on the obtained lithium battery temperature-internal resistance coupling analysis result, it is judged whether charge-discharge threshold dynamic regulation needs to be taken, the charge-discharge threshold dynamic regulation is used for dynamically adjusting the charge-discharge current threshold, and the problem of mismatch between discharge current and internal resistance caused by normal temperature threshold control is reduced, the output power-load adaptability monitoring module is used for output power-load adaptability monitoring for evaluating whether the actual output power of the lithium battery under low temperature meets the rated demand of the solar load light source after the lithium battery temperature-internal resistance coupling analysis is qualified, based on the obtained output power-load adaptability monitoring result, it is judged whether discharge power self-adaptive adjustment needs to be taken, the discharge power self-adaptive adjustment is used for improving the stability of solar street lamp load work under low temperature scene and the adaptability of lithium battery discharge capacity, the solar street lamp control stability monitoring module is used for solar street lamp control stability evaluation for evaluating the continuous stability of solar street lamp night work after the output power-load adaptability monitoring is qualified, based on the obtained solar street lamp control stability evaluation result, it is judged whether multi-level protection coordination needs to be taken, and the multi-level protection coordination is used for improving the charge-discharge control stability under low temperature.

[0009] The technical scheme provided by the embodiment of the present application has at least the following beneficial effects:

[0010] 1、By performing lithium battery temperature-internal resistance coupling analysis, based on the obtained lithium battery temperature-internal resistance coupling analysis result, it is determined whether dynamic adjustment of the charging and discharging threshold value is needed, which helps to reduce the misjudgment of the battery charging and discharging capacity due to the dependence of the constant temperature fixed lithium battery internal resistance parameter in the charging and discharging control circuit, improve the adaptation accuracy of the charging and discharging threshold value to the actual internal resistance and temperature state of the lithium battery at low temperature, and lay a foundation for subsequent stable discharge. After the lithium battery temperature-internal resistance coupling analysis is qualified, output power-load adaptability monitoring is performed, based on the obtained output power-load adaptability monitoring result, it is determined whether discharge power self-adaptive adjustment is needed, which helps to reduce the problem that the actual output current of the battery is insufficient due to the increase of the internal resistance of the low-temperature lithium battery, and the output power of the lithium battery is lower than the rated demand of the solar load light source, and reduces the working abnormity of the solar load due to power mismatch. After the output power-load adaptability monitoring is qualified, solar street lamp control stability evaluation for evaluating the continuous stability of the solar street lamp at night is performed, based on the obtained solar street lamp control stability evaluation result, it is determined whether multi-level protection coordination is needed, which helps to reduce the situation that the solar street lamp appears frequent flickering or power failure during the night lighting, and improves the overall stability of the intelligent charging and discharging control of the lithium battery in the low-temperature scene.

[0011] 2、By selecting lithium battery temperature variation coefficient and lithium battery internal resistance variation coefficient as basic coupling parameters, the state of the two core dimensions of the temperature fluctuation degree and the internal resistance variation amplitude of the lithium battery at low temperature can be fully captured, the dynamic cooperative relationship between temperature and internal resistance can be accurately reflected, and the problem that the existing technology only relies on constant temperature fixed internal resistance parameter in the charging and discharging control, and it is difficult to fully reflect the influence of temperature and internal resistance coupling change at low temperature on the charging and discharging performance can be solved. The result of the harmonic average processing of the basic coupling parameters and the influence value of the basic coupling parameters is taken as the temperature-internal resistance correlation evaluation index and the lithium battery temperature-internal resistance coupling state is distinguished, which helps to solve the problem of inaccurate charging and discharging threshold value adjustment caused by unrecognized temperature-internal resistance abnormal coupling, and reduces the situation that the temperature-internal resistance abnormal state directly enters the subsequent charging and discharging control process. It is determined whether the coupling abnormal counter value is greater than the preset coupling abnormal counter maximum threshold value, if yes, the charging and discharging threshold value dynamic adjustment is taken, and the coupling abnormal counter value in the next preset coupling analysis time period is reset to the initial value, otherwise, the lithium battery temperature-internal resistance coupling analysis is continued, which helps to reduce the misjudgment caused by accidental events, identifies and quantifies the coupling strength of temperature and internal resistance at low temperature from the source, provides accurate and reliable judgment basis for the dynamic adjustment of the charging and discharging threshold value, and improves the accuracy of the lithium battery charging and discharging control at low temperature.

[0012] 3、By selecting the lithium battery output power stability evaluation index, the load end voltage stability index and the lithium battery temperature influence index as the control stability quantization parameters, the three core dimension states of lithium battery power output fluctuation, load voltage deviation and temperature interference in the low temperature scene can be comprehensively captured, the full link stability of the system from battery discharge to load work can be accurately reflected, the problem that the risk of flash and power failure in the middle cannot be identified in advance due to the fact that only a single dimension is used to evaluate the stability in the charge and discharge control in the prior art can be solved, the result of the coupling processing of the control stability quantization parameters and the corresponding control stability influence parameters is used as the solar street lamp control stability evaluation index for evaluating the overall control stability degree of the solar street lamp, identifying the risk of flash and power failure in the middle in advance, the interference degree of low temperature on the battery performance and system control can be accurately quantified, the comprehensive quantitative evaluation of the overall control stability is realized, the problem that the fault is passively handled after the fault occurs due to the lack of systematic evaluation and early intervention mechanism of the control stability in the prior art can be solved, whether the solar street lamp control stability evaluation index is greater than the preset control stability threshold is judged, if yes, the intelligent charge and discharge of the solar street lamp is continued, and the basic coupling parameters are continuously monitored, otherwise, multi-level protection coordination is performed, the potential risk can be identified in advance and the protection measures can be triggered, the instability of the charge and discharge control caused by the superposition of power fluctuation, voltage deviation or temperature interference in the low temperature is effectively reduced, and the stability of the intelligent charge and discharge control of the lithium battery in the low temperature scene and the reliability of the operation of the solar street lamp are improved. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0014] Figure 1 is a structural schematic diagram of a lithium battery intelligent charge and discharge control system for a solar street lamp provided by an embodiment of the present application;

[0015] Figure 2 is a general overview flow of a lithium battery intelligent charge and discharge control system for a solar street lamp provided by an embodiment of the present application Figure 1 ;

[0016] Figure 3 is a general overview flow of a lithium battery intelligent charge and discharge control system for a solar street lamp provided by an embodiment of the present application Figure 2 ;

[0017] Figure 4The application provides a kind of solar street lamp lithium battery intelligent charge-discharge control system charge-discharge threshold dynamic regulation logic diagram provided by the embodiment of the application. DETAILED DESCRIPTION

[0018] The technical solutions in the application will be described below with reference to the drawings.

[0019] As Figure 1 shown, it is the structure schematic diagram of a kind of solar street lamp lithium battery intelligent charge-discharge control system provided by the embodiment of the application, a kind of solar street lamp lithium battery intelligent charge-discharge control system, comprising: lithium battery temperature-internal resistance coupling monitoring module, output power-load adaptability monitoring module and solar street lamp control stability monitoring module:

[0020] Among them, lithium battery temperature-internal resistance coupling monitoring module is used to in lithium battery intelligent charge-discharge control process, for guaranteeing lithium battery charge-discharge safety, reducing the lithium battery temperature-internal resistance coupling analysis that temperature and internal resistance coupling abnormality lead to overcharge overdischarge, based on the lithium battery temperature-internal resistance coupling analysis result obtained whether need to take charge-discharge threshold dynamic regulation, charge-discharge threshold dynamic regulation is used to adapt the internal resistance of lithium battery that significantly increases at low temperature, dynamically lower charge-discharge current threshold, reduce the problem that discharge current and internal resistance do not match due to normal temperature threshold control;By monitoring lithium battery temperature-internal resistance coupling analysis result, it is helpful to reduce the problem that charge-discharge control circuit misjudges battery charge-discharge capacity due to dependence on normal temperature fixed internal resistance parameter from source, provides stable battery state basis for subsequent output power-load adaptability.

[0021] Output power-load adaptability monitoring module is used to after lithium battery temperature-internal resistance coupling analysis is qualified, for evaluating whether the actual output power of lithium battery at low temperature meets the rated demand of solar load light source, output power-load adaptability monitoring is carried out, based on the output power-load adaptability monitoring result obtained whether need to take discharge power self-adapting adjustment, discharge power self-adapting adjustment is used to reduce the abnormal operation of load caused by insufficient power, improve the stability of solar street lamp load operation and the adaptability of lithium battery discharge capacity under low temperature scene;Through output power-load adaptability monitoring result, it is helpful to find the deviation of lithium battery output power and load rated demand at low temperature in time, reduce the problem that solar load is directly caused by power mismatch, such as frequent flashing, brightness instability, etc., link the matching link of battery state and load operation well.

[0022] The solar street lamp control stability monitoring module is used for evaluating the continuous stability of the solar street lamp at night after the output power-load adaptability monitoring is qualified. Based on the obtained solar street lamp control stability evaluation results, it is judged whether multi-level protection coordination is needed. The multi-level protection coordination is used to improve the charge-discharge control stability at low temperature and ensure the reliable operation of the street lamp at night. By monitoring the solar street lamp control stability evaluation results, it is helpful to identify the stability risk in the night operation of the solar street lamp in advance and ensure the continuous and reliable operation of the street lamp at low temperature.

[0023] It should be understood that the lithium battery intelligent charge-discharge control system for solar street lamps provided by the present application pre-constructs a database for storing various types of setting data in the design stage. The data sources of the database include not only the basic preset values such as preset lithium battery temperature variation threshold, preset coupling threshold, preset coupling abnormality counter maximum threshold, and preset stability threshold configured directly by technical personnel, but also reference data sets formed by sorting historical solar street lamp operation cases (such as lithium battery charge-discharge parameter records in different environments, street lamp flickering / power failure data) and outdoor low temperature experiment data (such as charge-discharge threshold adaptability verification results in multiple low temperature scenarios), which provide outdoor practice support for the rationality of the preset values. The storage adopts an encrypted distributed architecture, which combines a relational database to store structured preset parameters (such as specific values of various thresholds, weight coefficient value ranges of control stability evaluation, etc.) and a non-relational database to store unstructured reference data (such as historical lithium battery temperature-internal resistance variation time series curves, street lamp night lighting state monitoring video clips, etc.). Technical personnel can dynamically calibrate the preset values according to newly accumulated solar street lamp low temperature operation data and fault feedback, so that the stored data always adapt to the needs of lithium battery intelligent charge-discharge control in actual outdoor low temperature scenarios.

[0024] In this embodiment, a complete intelligent charging and discharging system for solar street light lithium batteries in low-temperature scenarios is constructed through the collaborative efforts of a lithium battery temperature-internal resistance coupling monitoring module, an output power-load adaptability monitoring module, and a solar street light control stability monitoring module. This ultimately improves the charging and discharging safety and continuous operational reliability of solar street lights in low-temperature environments, helping to solve problems such as charging and discharging misjudgments, power mismatches, and unstable street light operation caused by changes in the internal resistance of lithium batteries at low temperatures. Specifically, the lithium battery temperature-internal resistance coupling monitoring module reduces the problem of misjudgment of charging and discharging capabilities caused by increased internal resistance of lithium batteries at low temperatures, and improves the charging and discharging threshold and real-time internal resistance of lithium batteries in low-temperature scenarios. The temperature-load adaptability monitoring module, which inherits the qualified and stable battery status results from the lithium battery temperature-internal resistance coupling monitoring module, verifies the matching degree between the actual output power of the lithium battery and the rated load requirements, provided that the battery status is qualified. The qualified result lays a good foundation for the battery and load matching of the solar street light control stability monitoring module, reducing the risk of power mismatch directly affecting the system stability. Based on the qualified battery status and qualified power adaptation, the solar street light control stability monitoring module further evaluates the continuous stability of the street light's nighttime operation, ensuring the accuracy and stability of the entire charging and discharging control system in low-temperature environments.

[0025] like Figure 2 The diagram shows a general overview flow of a smart charging and discharging control system for lithium batteries used in solar streetlights, provided by an embodiment of the present invention. Figure 1 ,Depend on Figure 2 It can be seen that during the intelligent charging and discharging control of lithium batteries, temperature-internal resistance coupling analysis is performed, and the temperature-internal resistance correlation evaluation index is obtained. It is determined whether the temperature-internal resistance correlation evaluation index is greater than the preset coupling threshold. If not, the intelligent charging and discharging of the solar street light continues, and the basic coupling parameters are continuously monitored. Otherwise, an over-limit judgment of the coupling anomaly counter is performed, and the value of the coupling anomaly counter is obtained. It is determined whether the value of the coupling anomaly counter is greater than the preset maximum threshold of the coupling anomaly counter. If not, the temperature-internal resistance coupling analysis of the lithium battery continues; otherwise, dynamic adjustment of the charging and discharging threshold is adopted. After the dynamic adjustment is completed, it is determined whether the lithium battery temperature-internal resistance coupling analysis is qualified. If it is not qualified, a failure warning is sent. Otherwise, output power-load adaptability monitoring is performed, and the output power adaptability deviation rate is obtained. It is determined whether the output power adaptability deviation rate is less than the preset output power adaptability threshold. If it is, the stability assessment of solar street light control is performed. Otherwise, the discharge power adaptive adjustment is adopted. After the discharge power adaptive adjustment is completed, it is determined whether the output power-load adaptability monitoring is qualified. If it is not qualified, a discharge power adjustment failure warning is sent. Otherwise, the stability assessment of solar street light control is performed.

[0026] likeFigure 3 As shown in the figure, it is a general overview of the intelligent charging and discharging control system of lithium battery for solar street lamp provided by the embodiment of the application Figure 2 , by Figure 3 It can be known that the control stability of the solar street lamp is evaluated, and the control stability evaluation index of the solar street lamp is obtained. It is judged whether the control stability evaluation index of the solar street lamp is greater than the preset control stability threshold. If yes, the intelligent charging and discharging of the solar street lamp is continued to be executed, and the basic coupling parameters are continuously monitored. Otherwise, multi-level protection coordination is carried out, and the control stability deviation value is obtained. It is judged whether the control stability deviation value meets the delay confirmation protection condition. If yes, the delay confirmation protection is started. If not, it is judged whether the control stability deviation value meets the hierarchical load shedding protection condition. If not, the intelligent charging and discharging of the solar street lamp is continued to be executed, and the basic coupling parameters are continuously monitored. Otherwise, the hierarchical load shedding protection is started. After the hierarchical load shedding protection is ended, it is judged whether the control stability evaluation of the solar street lamp is qualified. If yes, the intelligent charging and discharging of the solar street lamp is continued to be executed, and the basic coupling parameters are continuously monitored. Otherwise, the hierarchical load shedding protection failure early warning is sent.

[0027] Preferably, the specific process of the lithium battery temperature-internal resistance coupling analysis is as follows: obtaining basic coupling parameters, the basic coupling parameters including a lithium battery temperature change coefficient for quantifying the degree of temperature fluctuation of the lithium battery in a low-temperature environment and a lithium battery internal resistance change coefficient for quantifying the amplitude of the change of the lithium battery internal resistance with temperature in the low-temperature environment; judging whether the basic coupling parameters meet the lithium battery temperature-internal resistance cooperative change condition, if yes, obtaining a temperature-internal resistance correlation degree evaluation index for evaluating the influence degree of the change of the lithium battery temperature and internal resistance on the charging and discharging performance in the low-temperature environment, otherwise, continuing to perform intelligent charging and discharging of the solar street lamp and continuously monitoring the basic coupling parameters; the lithium battery temperature-internal resistance cooperative change condition means that the lithium battery temperature change coefficient is greater than 0 and the lithium battery internal resistance change coefficient is greater than 0; the temperature-internal resistance correlation degree evaluation index is represented by the result of the harmonic average processing of the basic coupling parameters and the basic coupling parameter influence value, wherein when the lithium battery temperature change coefficient increases, it indicates that the fluctuation amplitude of the lithium battery temperature in the low-temperature outdoor environment is more intense, thereby causing the lithium battery internal resistance change coefficient to increase, indicating that the amplitude of the lithium battery internal resistance fluctuation with temperature changes simultaneously (temperature instability at low temperature will exacerbate the nonlinear change of internal resistance), when the lithium battery temperature change coefficient and the lithium battery internal resistance change coefficient increase simultaneously, the temperature-internal resistance correlation degree evaluation index further increases; the basic coupling parameter influence value includes a battery temperature change influence value for reflecting the influence degree of the lithium battery temperature change coefficient on the temperature-internal resistance correlation degree evaluation index and a lithium battery internal resistance change influence value for reflecting the influence degree of the lithium battery internal resistance change coefficient on the temperature-internal resistance correlation degree evaluation index; the lithium battery temperature change coefficient is represented by the result of the deviation quantification of the highest temperature and the lowest temperature of the lithium battery monitored by the lithium battery surface temperature sensor in a preset coupling analysis time period and the proportion quantification thereof with a preset lithium battery temperature change threshold value, wherein the deviation quantification means difference operation, the proportion quantification means ratio operation, and the preset lithium battery temperature change threshold value is represented by the average value of the lithium battery temperature change amount in a historical time period; the lithium battery internal resistance change coefficient is represented by the result of the deviation quantification of the maximum internal resistance and the minimum internal resistance of the lithium battery monitored by the lithium battery internal resistance detector in the preset coupling analysis time period and the proportion quantification thereof with a preset lithium battery internal resistance change threshold value, wherein the preset lithium battery internal resistance change threshold value is represented by the average value of the lithium battery internal resistance change amount in a historical time period; the preset coupling analysis time period represents the time period for performing the lithium battery temperature-internal resistance coupling analysis; and the lithium battery temperature-internal resistance coupling state is discriminated based on the temperature-internal resistance correlation degree evaluation index.

[0028] Specifically, the lithium battery temperature-internal resistance coupling state discrimination is used to accurately discriminate the abnormal coupling state of the lithium battery temperature and internal resistance at low temperature, and the specific process is as follows: judging whether the temperature-internal resistance correlation degree evaluation index is greater than a preset coupling threshold value, if yes, the coupling abnormality counter value is added, and the coupling abnormality counter is used to reduce the temperature and internal resistance coupling abnormality caused by single or short-term accidental abnormal interference, and ensure the accuracy of the coupling abnormality judgment, otherwise, the solar street lamp intelligent charging and discharging is continued to be executed, and the basic coupling parameters are continuously monitored, wherein the preset coupling threshold value is represented by the average value of the temperature-internal resistance correlation degree evaluation index in the historical time period; the specific process of the coupling abnormality counter over-limit discrimination is as follows: judging whether the coupling abnormality counter value is greater than a preset coupling abnormality counter maximum threshold value, if yes, the charging and discharging threshold value is dynamically adjusted, and the coupling abnormality counter value in the next preset coupling analysis time period is reset to the initial value, otherwise, the lithium battery temperature-internal resistance coupling analysis is continued to be executed, wherein the preset coupling abnormality counter maximum threshold value is set in advance by the preset personnel.

[0029] It should be understood that in the lithium battery temperature-internal resistance coupling analysis and the solar street lamp control stability evaluation provided by the present application, a plurality of parameter mapping sets for quantifying the influence degree of each parameter on the corresponding evaluation result are involved, which together constitute a mapping group, and are set in advance by professional technicians and stored in a database, providing a matching basis for the influence values of the basic coupling parameters (lithium battery temperature change coefficient, lithium battery internal resistance change coefficient), control stability quantification parameters (lithium battery output power stability evaluation index, load end voltage stability index, lithium battery temperature influence index). The corresponding rules in the mapping group represent the influence value or influence factor proportion in the numerical range of 0 to 1, achieving one-to-one mapping or many-to-one adaptation of the input parameter combination and the corresponding influence value or influence factor in different analysis scenarios.

[0030] Specifically, for example, a large number of actual historical data of low-temperature outdoor solar street lamp operation are extracted first, and the parameter combinations of two types of core analysis scenes (such as the numerical combination of the lithium battery temperature change coefficient and the corresponding battery temperature change influence value, the lithium battery internal resistance change coefficient and the corresponding lithium battery internal resistance change influence value in the lithium battery temperature-internal resistance coupling analysis scene; the value combination of the lithium battery output power stability evaluation index and the corresponding lithium battery output power influence factor, the load end voltage stability index and the corresponding load end voltage influence factor, and the lithium battery temperature influence index and the corresponding lithium battery temperature influence factor in the solar street lamp control stability evaluation scene) are covered, and a quantitative value based on the influence degree of the corresponding evaluation result is given to the input parameters of each type of scene. The actual effective values of the corresponding influence values and influence factors in each historical scene are recorded synchronously, and then the correlation analysis (such as Pearson correlation coefficient analysis) is performed to eliminate abnormal associated data caused by sudden disturbances in low-temperature environment (such as temperature sudden change caused by cold wave, temporary abnormality of circuit caused by snowstorm), temporary faults of lithium battery (such as instantaneous fluctuation of internal resistance, sudden drop of voltage), and temporary adaptive deviation of charge-discharge control circuit, and the corresponding relationship between the parameter combinations with statistical significance and the influence values or influence factors is retained. Finally, all the effective data are integrated to form a mapping group containing multiple mapping sets, and when the system carries out lithium battery temperature-internal resistance coupling analysis, solar street lamp control stability evaluation and other work, the matching influence values or influence factors can be quickly retrieved from the mapping group to ensure the accuracy and reliability of the temperature-internal resistance correlation degree evaluation index and the solar street lamp control stability evaluation index.

[0031] In the embodiment, by performing lithium battery temperature-internal resistance coupling analysis, the coordinated fluctuation state of the lithium battery temperature change coefficient and the internal resistance change coefficient in the low-temperature environment is accurately identified, which helps to provide accurate state basis for dynamic regulation of the charge-discharge threshold, reduces the regulation error caused by using the fixed internal resistance parameter at normal temperature, reduces the probability of misjudgment of the lithium battery charge-discharge capacity by the charge-discharge control circuit, and reduces the overcharge and overdischarge risk caused by the mismatch between the discharge current and the increased internal resistance at low temperature, thereby improving the safety and adaptability of the lithium battery charge-discharge control in the low-temperature scene, and providing a stable battery state basis for subsequent output power-load adaptability monitoring.

[0032] As shown in Figure 4 , a charge-discharge threshold dynamic regulation logic diagram of a lithium battery intelligent charge-discharge control system for a solar street lamp provided by the embodiment of the present application is shown in Figure 4It can be known that: the dynamic regulation of the charging and discharging threshold value represents the sequence of the charging phase threshold value parameter correction and the discharging phase threshold value parameter correction, after the charging phase threshold value parameter correction is completed, the charging current stability evaluation index is reacquired, it is judged whether the charging current stability evaluation index is less than the preset stability threshold value, if not, the charging parameter correction failure warning is sent, otherwise, the discharging phase threshold value parameter correction is carried out, and it is judged whether the maximum allowed continuous discharging current is greater than the solar load driver rated current, if yes, the output power-load adaptability monitoring is carried out, otherwise, the discharging current upper limit adjustment is carried out, after the discharging current upper limit adjustment is completed, the load end voltage stability evaluation index is reacquired, it is judged whether the load end voltage stability evaluation index is less than the preset load fluctuation threshold value, if yes, the output power-load adaptability monitoring is carried out, otherwise, the discharging parameter correction failure warning is sent.

[0033] Preferably, the specific process of dynamic regulation of the charging and discharging threshold is as follows: the historical multi-dimensional running data set of the lithium battery (including internal resistance data and corresponding safe charging and discharging current labels under different temperatures, SOC, and cycle times) is divided into a historical running data training set and a historical running data test set, the parameters of a preset battery charging and discharging capacity estimation model, such as a first-order RC (First-order Resistor-Capacitor, first-order resistor-capacitor) model or a second-order RC model, are iteratively optimized through the historical running data training set, and the model output precision is verified by using the historical running data test set to complete model training. The current battery internal resistance is input into the trained preset battery charging and discharging capacity estimation model, and the maximum allowed charging current and the maximum allowed continuous discharging current are output. The preset battery charging and discharging capacity estimation model is used to quantify the maximum charging current and the upper limit of the continuous discharging current that the battery can safely withstand at the current temperature, providing a current limit reference basis for subsequent charging and discharging threshold parameter correction. The charging phase threshold parameter correction is performed to improve the battery safety in the charging phase, ensure that the charging current is stable and adapted to the dynamic performance of the battery, and improve the charging efficiency. The specific process is as follows: the temperature-internal resistance correlation evaluation index and the maximum allowed charging current are input into the preset parameter adjustment strategy mapping table in the database for query to obtain a charging current adjustment coefficient; the amplitude corresponding to the charging current adjustment coefficient is taken as the adjustment step, and the charging current upper limit is adjusted step by step in the direction of decreasing the charging current adjustment coefficient (after completing each charging current upper limit adjustment, the charging current stability evaluation index is recalculated. If the charging current stability evaluation index is still not less than the preset stability threshold, the charging current upper limit after this adjustment is taken as the initial value for the next adjustment, and the charging current upper limit is adjusted step by step in the direction of decreasing the charging current adjustment coefficient). This helps to reduce the sudden drop or fluctuation of the charging current caused by one-time large-scale adjustment, so that the current is stable in the interval that adapts to the current state of the battery, reduces the loss of charging efficiency and the impact of current fluctuation on the battery; the charging current upper limit is less than the maximum allowed charging current; the charging current stability evaluation index is continuously monitored. If the charging current stability evaluation index is less than the preset stability threshold, the discharging phase threshold parameter correction is performed. Otherwise, the charging phase threshold parameter correction is continued. When the number of charging phase threshold parameter correction is greater than the preset maximum number of charging phase threshold parameter correction, if the charging current stability evaluation index is still not less than the preset stability threshold, a charging parameter correction failure warning is sent. The preset stability threshold is represented by the average value of the charging current stability evaluation index in the historical time period, and the preset maximum number of charging phase threshold parameter correction is set by the preset personnel in advance. The charging current stability evaluation index is represented by the fluctuation amplitude of the charging current in the preset coupling analysis time period, wherein the fluctuation amplitude of the charging current is represented by the deviation between the maximum sampling value and the minimum sampling value of the charging current monitored by the current sensor in the preset coupling analysis time period.

[0034] Specifically, the discharge phase threshold parameter correction is used to reduce the problem of mismatch between the actual discharge current and the battery capacity caused by the use of the fixed discharge current upper limit threshold at room temperature, and to improve the safety of the discharge process and the stability of the load work. The specific process is as follows: judging whether the maximum allowed continuous discharge current is greater than the solar load driver rated current, if yes, then performing output power-load adaptability monitoring, otherwise, performing discharge current upper limit adjustment, wherein the solar load driver rated current is set in advance by the preset personnel; the discharge current upper limit adjustment means that the temperature-internal resistance correlation evaluation index and the maximum allowed continuous discharge current are input into the preset discharge threshold adjustment mapping table in the database for query to obtain the discharge current adjustment coefficient; the amplitude corresponding to the discharge current adjustment coefficient is used as the adjustment step to gradually adjust the solar load driving current upper limit in the direction of reducing the lithium battery discharge current (after each solar load driving current upper limit adjustment is completed, the load end voltage stability evaluation index is recalculated, and if the load end voltage stability evaluation index is still not less than the preset load fluctuation threshold, then the solar load driving current upper limit after this adjustment is taken as the initial value for the next adjustment to gradually adjust the lithium battery discharge current in the direction of reducing the lithium battery discharge current), which helps to reduce the solar load flicker or brightness sudden change caused by the too large discharge current adjustment amplitude, and realizes the smooth adaptation of the load driving current to the battery discharge capacity at low temperature; the load end voltage stability evaluation index is continuously monitored, and when the load end voltage stability evaluation index is less than the preset load fluctuation threshold, the output power-load adaptability monitoring is performed, otherwise the discharge current upper limit adjustment is continued, and when the discharge current upper limit adjustment times are greater than the preset maximum discharge current upper limit adjustment times, if the load end voltage stability evaluation index is still not less than the preset stability threshold, a discharge parameter correction failure warning is sent, wherein the preset load fluctuation threshold is represented by the average value of the load end voltage stability evaluation index in the historical time period, and the preset maximum discharge current upper limit adjustment times are set in advance by the preset personnel; the load end voltage stability evaluation index is represented by the standard deviation of the actual sampling value of the voltage monitored by the load end voltage sensor of the solar load driver and the preset voltage threshold in the preset coupling analysis time period, which is used to quantify the stability of the output voltage of the solar load driver, wherein the preset voltage threshold is represented by the average value of the load end voltage in the historical time period.

[0035] It should be understood that the preset parameter adjustment strategy mapping table and the preset discharge threshold adjustment mapping table involved in the intelligent charging and discharging control of the solar street lamp lithium battery are pre-set by professional technicians and stored in a database. The matching of the charging current adjustment coefficient and the discharging current adjustment coefficient provides accurate basis, ensures that the upper limit adjustment of the charging and discharging current in the low-temperature scene can adapt to the actual performance state of the lithium battery, and when the system carries out threshold parameter correction in the charging stage, the charging current adjustment coefficient matched with the current temperature-internal resistance correlation evaluation index and the maximum allowed charging current can be quickly retrieved from the preset parameter adjustment strategy mapping table. When the upper limit of the discharging current is adjusted, the matched discharging current adjustment coefficient can be retrieved from the preset discharge threshold adjustment mapping table.

[0036] Specifically, a large amount of historical data of low-temperature outdoor solar street lamp charging and discharging operation is extracted first: for the preset parameter adjustment strategy mapping table, different temperature-internal resistance correlation evaluation index intervals (such as low correlation interval, medium correlation interval), different maximum allowed charging current ranges and corresponding charging current adjustment coefficient parameter combinations are covered, and the adaptive quantitative values based on charging safety and efficiency are assigned; for the preset discharge threshold adjustment mapping table, different temperature-internal resistance correlation evaluation index intervals, different maximum allowed continuous discharging current ranges and corresponding discharging current adjustment coefficient combinations are collected, and quantitative values are assigned in combination with the rated current demand of the solar load driver, for example, when the maximum allowed continuous discharging current is in the range below the rated current of the load, the matched adaptive discharging current adjustment coefficient is matched to ensure that the current is lowered to a certain extent to maintain the normal working state of the load; at the same time, the actual effective values of the charging current adjustment coefficient and the discharging current adjustment coefficient in each scene are recorded, and through correlation analysis (such as Pearson correlation coefficient), abnormal correlation data caused by low-temperature environment interference (such as temperature sudden change caused by cold wave, circuit impedance change caused by snow cover), temporary fault of lithium battery (such as instantaneous jump of internal resistance, voltage fluctuation), and temporary adaptive deviation of charging and discharging control module are excluded, and the corresponding relationship between the parameter combination and the adjustment coefficient with statistical significance is retained, and finally the two types of mapping tables are integrated.

[0037] In this embodiment, through the dynamic regulation of the charging and discharging threshold, it is helpful to lay a stable charging and discharging foundation for subsequent output power-load adaptability monitoring, improve the adaptability of the charging and discharging parameters and the real-time state of the battery in low temperature, reduce the overcharging and overdischarging risk caused by fixed threshold at normal temperature, and the problems such as charging current fluctuation, solar load flicker or brightness sudden change in the discharging stage caused by one-time large adjustment, improve the charging efficiency and discharging safety of the lithium battery in low temperature scene, and enhance the stability of the solar load driver, realize the dynamic linkage of the real-time state of the lithium battery and the charging and discharging threshold, and ensure the continuous and reliable operation of the intelligent charging and discharging control system of the solar street lamp in low-temperature outdoor environment.

[0038] Preferably, the specific process of output power-load adaptability monitoring is as follows: obtaining an output power adaptability deviation rate for evaluating the adaptability degree of the actual output power of the lithium battery and the load power of the solar load driver; the output power adaptability deviation rate is represented by the ratio of the result of deviation quantization of the lithium battery output power and the solar load driver load power to the result of proportion quantization of the solar load driver load power, the lithium battery output power is represented by the result of multiplication of the lithium battery operating voltage monitored by the voltage sensor and the lithium battery discharge current monitored by the current sensor, and the solar load driver load power is represented by the result of multiplication of the solar load driver output voltage monitored by the voltage sensor and the solar load driver operating current monitored by the current sensor; judging whether the output power adaptability deviation rate is less than a preset output power adaptation threshold value, if yes, performing solar street lamp control stability evaluation, otherwise, taking discharge power self-adaptive adjustment, wherein the preset output power adaptation threshold value is represented by the average value of the output power adaptability deviation rate in the historical time period.

[0039] Specifically, the specific process of discharge power self-adaptive adjustment is as follows: obtaining a battery maximum output power for evaluating the adaptability degree of the actual output power of the lithium battery and the load power of the solar load driver under low temperature; the battery maximum output power is represented by the result of multiplication of the battery maximum allowable continuous discharge current and the battery operating voltage; performing matching operation based on the battery maximum output power; the matching operation is used to obtain a load target power accurately matched with the current battery power supply capability based on a load power adjustment algorithm (such as a linear programming-least squares fitting algorithm); adjusting the output power of the solar load driver to the load target power based on a smoothing filtering algorithm (such as a linear gradual change algorithm, an S-curve acceleration planning algorithm, etc.); after the discharge power self-adaptive adjustment is completed, the output power adaptability deviation rate is re-obtained, if the output power adaptability deviation rate is still not less than the preset output power adaptation threshold value, a discharge power adjustment failure warning is sent, otherwise, solar street lamp control stability evaluation is performed.

[0040] In this embodiment, through output power-load adaptability monitoring and discharge power self-adaptive adjustment, the problem of mismatch between the output power of the lithium battery and the load rated power due to the increase of internal resistance under low temperature is solved, the abnormal brightness, flickering of the solar load (such as LED lamp) and the excessive consumption of the lithium battery caused by forcibly outputting power beyond the capability range are reduced, the adaptability accuracy of the discharge capability of the lithium battery and the power demand of the solar load under low temperature is improved, and the impact on the load during power adjustment is avoided, realizing dynamic adaptation of the lithium battery power supply capability and the load power demand, breaking the limitation of traditional fixed power control that cannot cope with low temperature internal resistance changes, and providing a stable power basis for subsequent solar street lamp control stability evaluation.

[0041] Preferably, the specific process of the solar street lamp control stability evaluation is as follows: obtaining control stability quantitative parameters; the control stability quantitative parameters include a lithium battery output power stability evaluation index for quantifying the fluctuation degree of the lithium battery output power, a load end voltage stability index for reflecting the deviation of the load end voltage from the rated voltage, and a lithium battery temperature influence index for embodying the interference degree of temperature change on the lithium battery performance and system control stability; the result of the weighted coupling processing of the control stability quantitative parameters and the corresponding control stability influence parameters is taken as the solar street lamp control stability evaluation index for evaluating the overall control stability degree of the solar street lamp, identifying the risk of strobe and power outage in advance; the weighted coupling processing represents the multiplication operation; the control stability influence parameters include a lithium battery output power influence factor for reflecting the influence degree of the lithium battery output power stability evaluation index on the solar street lamp control stability evaluation index, a load end voltage influence factor for reflecting the influence degree of the load end voltage stability index on the solar street lamp control stability evaluation index, and a lithium battery temperature influence factor for reflecting the influence degree of the lithium battery temperature influence index on the solar street lamp control stability evaluation index; it is judged whether the solar street lamp control stability evaluation index is greater than a preset control stability threshold value, if yes, the solar street lamp intelligent charging and discharging is continuously performed, and the basic coupling parameters are continuously monitored, otherwise, multi-level protection coordination is performed; the preset control stability threshold value is represented by the average value of the solar street lamp control stability evaluation index in a historical time period.

[0042] Specifically, the specific formula of the lithium battery output power stability evaluation index is as follows:

[0043]

[0044] wherein, I P represents the lithium battery output power stability evaluation index, A represents the lithium battery output power, P max represents the maximum average value of the lithium battery output power; specifically, the lithium battery output power is represented by the result of the multiplication operation of the lithium battery voltage monitored by the lithium battery end voltage sensor and the lithium battery current monitored by the discharging current sensor; the maximum average value of the lithium battery output power is represented by the average value of the lithium battery output power in the discharging stage in a historical time period.

[0045] Specifically, the specific formula of the load end voltage stability index is as follows:

[0046]

[0047] wherein, I VThe load end voltage stability index is represented, V1 represents the actual working voltage of the load, and V2 represents the rated working voltage of the load. Specifically, the actual working voltage of the load is monitored by a load end voltage sensor, and the rated working voltage of the load is set in advance by a preset person.

[0048] Specifically, the specific formula of the lithium battery temperature influence index is as follows:

[0049]

[0050] Wherein, I T The lithium battery temperature influence index is represented, T1 represents the actual working temperature of the lithium battery, T2 represents the preset battery working temperature, and T3 represents the preset lower limit of the lithium battery low-temperature working temperature. Specifically, the actual working temperature of the lithium battery is monitored by a lithium battery surface temperature sensor, the preset battery working temperature is represented by the average value of the lithium battery working temperature in a historical time period, and the preset lower limit of the lithium battery low-temperature working temperature is set in advance by a preset person.

[0051] Specifically, the specific formula of the solar street lamp control stability evaluation index is as follows:

[0052]

[0053] Wherein, S represents the solar street lamp control stability evaluation index, W P The lithium battery output power influence factor is represented, W V The load end voltage influence factor is represented, W T The lithium battery temperature influence factor is represented.

[0054] In this embodiment, through the solar street lamp control stability evaluation, the quantitative indexes are constructed from the three core dimensions of lithium battery output power fluctuation, load end voltage stability, and temperature interference to the system, the comprehensive evaluation index is constructed, the overall control stability degree of the street lamp is comprehensively quantified, which helps to identify the risk of flashing and power failure caused by the superposition of power fluctuation, voltage deviation, and temperature interference in advance, provides accurate starting basis for multi-level protection coordination, solves the problem of sudden failure caused by lack of systematic stability evaluation in traditional control, reduces the operation interruption caused by potential unstable factors not being discovered in time during the night operation of the solar street lamp, improves the overall stability and reliability of the street lamp control in low-temperature scenes, and at the same time, through continuous monitoring and threshold judgment, a closed loop mechanism is formed, which provides guarantee for the long-term stable operation of the solar street lamp intelligent charging and discharging control system.

[0055] Preferably, the specific process of multi-stage protection coordination is as follows: obtaining a control stability deviation value for evaluating the degree of stability of the overall control logic of the solar street lamp; the control stability deviation value is represented by the result of deviation quantization of the solar street lamp control stability evaluation index and the preset control stability threshold; the specific process of the grading protection discrimination for reducing the frequency flicker or power failure of the solar street lamp caused by insufficient control stability and improving the overall control stability of the solar street lamp in low temperature environment is as follows: judging whether the control stability deviation value meets the delay confirmation protection condition, if it meets, starting the delay confirmation protection for preventing system malfunction caused by transient disturbance; otherwise, continuing to judge whether the control stability deviation value meets the grading load shedding protection condition, if it meets, starting the grading load shedding protection for avoiding deep discharge of lithium battery or circuit overload caused by excessive load, otherwise, continuing to execute the intelligent charging and discharging of the solar street lamp and continuously monitoring the basic coupling parameters; the delay confirmation protection condition represents that the control stability deviation value is greater than the preset first-stage protection threshold and less than the preset second-stage protection threshold; the grading load shedding protection condition represents that the control stability deviation value is greater than the preset second-stage protection threshold, wherein the first-stage protection threshold and the second-stage protection threshold are set in advance by the preset personnel; the specific process of the delay confirmation protection is as follows: starting a delay confirmation timer, continuously monitoring the duration that the control stability deviation value meets the delay confirmation protection condition, judging whether the delay confirmation timer monitoring value is greater than the preset protection trigger threshold, if it is, starting the grading load shedding protection, otherwise, continuing to execute the intelligent charging and discharging of the solar street lamp and continuously monitoring, wherein the preset protection trigger threshold is set in advance by the preset personnel.

[0056] Specifically, the specific process of the hierarchical load shedding protection is as follows: based on the input control stability deviation value, the load driver load shedding amplitude operation is performed; the load driver load shedding amplitude operation represents that the solar load driver load shedding ratio for improving the adaptability of the load power to the current discharge capacity of the lithium battery and reducing the control stability deviation is output through a PID (Proportional-Integral-Derivative) algorithm; it is judged whether the solar load driver load shedding ratio is greater than a preset maximum load shedding threshold value, if yes, the solar load driver load shedding ratio is set to the preset maximum load shedding threshold value, which helps to prevent the load shedding amplitude from being too large to cause the solar load lamp brightness to be lower than the basic lighting requirement threshold value, and at the same time avoids the battery from entering a non-stable discharge state due to excessive load shedding, thereby protecting the core lighting function and the battery safety; otherwise, the solar load driver load shedding ratio and the solar load driver load power are coupled and analyzed to obtain a corresponding power adjustment instruction and send it to the charge-discharge control center, and the output current reference of the solar load driver is adjusted based on the function adjustment instruction, wherein the preset maximum load shedding threshold value is represented by the average value of the historical time period solar load driver load shedding ratio; the coupling analysis represents that the solar load driver load shedding ratio and the solar load driver load power are multiplied to obtain a power setting value, and the power setting value is input into the charge-discharge control center to obtain the power adjustment instruction; the solar street lamp control stability evaluation index is continuously monitored, and when the solar street lamp control stability evaluation index is greater than a preset control stability threshold value, the intelligent charge-discharge of the solar street lamp is continuously executed, and the basic coupling parameters are continuously monitored; otherwise, a hierarchical load shedding protection failure warning is sent, wherein the power adjustment instruction represents a specific operation instruction generated by the charge-discharge control center based on the power setting value obtained through the coupling analysis, for guiding the solar load driver to adjust the output power, and the instruction clearly indicates the power setting value to which the load driver needs to adjust the output power, the adjustment rate (smooth adjustment rhythm matching the current discharge capacity of the lithium battery), and the output current reference range that needs to be maintained during the adjustment process, for ensuring that the load power can accurately adapt to the current discharge capacity of the lithium battery, while reducing the load working abnormity caused by power sudden change, and improving the operation stability of the solar street lamp.

[0057] In the embodiment, through multi-stage protection coordination, the risk level is determined by the control stability deviation value first, and then the progressive logic of delay confirmation protection to hierarchical load shedding protection is accurately responded, which not only filters transient interference through delay confirmation protection and reduces system misoperation, but also realizes dynamic adaptation of solar load and battery discharge capacity relying on hierarchical load shedding protection, forms a complete protection mechanism, helps to solve the problems of frequent flashing and power outage in the middle of the way caused by insufficient control stability of solar street lamps, reduces the deep discharge of lithium batteries or circuit overload caused by too high solar load, and reduces the influence of basic lighting function caused by too large load shedding amplitude, and improves the overall control stability and reliability of core lighting function of solar street lamps in low temperature scenes.

[0058] In summary, by performing lithium battery temperature-internal resistance coupling analysis, it is determined whether to take dynamic adjustment of charge and discharge threshold based on the obtained lithium battery temperature-internal resistance coupling analysis result, which helps to reduce the misjudgment of battery charge and discharge capacity caused by relying on constant temperature fixed lithium battery internal resistance parameter in the charge and discharge control circuit, improve the adaptation accuracy of charge and discharge threshold and actual internal resistance and temperature state of lithium battery in low temperature, and lay a foundation for subsequent stable discharge. After the lithium battery temperature-internal resistance coupling analysis is qualified, output power-load adaptability monitoring is performed, and it is determined whether to take discharge power self-adaptive adjustment based on the obtained output power-load adaptability monitoring result, which helps to reduce the problem that the actual output current of the battery is insufficient due to the increase of the internal resistance of the low-temperature lithium battery, and the output power of the lithium battery is lower than the rated demand of the solar load light source, and reduces the working abnormity of the solar load due to power mismatch. After the output power-load adaptability monitoring is qualified, the control stability evaluation of the solar street lamp is performed for evaluating the continuous stability of the solar street lamp at night, and it is determined whether to take multi-stage protection coordination based on the obtained control stability evaluation result of the solar street lamp, which helps to reduce the frequent flashing or power outage of the solar street lamp at night, and improves the overall stability of the intelligent charge and discharge control of the lithium battery in low temperature scenes.

[0059] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A lithium battery intelligent charge-discharge control system for solar street lamps, characterized in that, The application relates to a lithium battery temperature-internal resistance coupling monitoring module, an output power-load adaptability monitoring module and a solar street lamp control stability monitoring module. The lithium battery temperature-internal resistance coupling monitoring module is used for lithium battery temperature-internal resistance coupling analysis for guaranteeing lithium battery charging and discharging safety in the process of intelligent lithium battery charging and discharging control, and whether dynamic regulation and control of a charging and discharging threshold value is needed is judged based on the acquired lithium battery temperature-internal resistance coupling analysis result; the dynamic regulation and control of the charging and discharging threshold value is used for dynamically lowering the charging and discharging current threshold value, and reducing the problem of discharging current and internal resistance mismatch caused by normal temperature threshold value control. The output power-load adaptability monitoring module is used for output power-load adaptability monitoring for evaluating whether the actual output power of the lithium battery under low temperature meets the rated demand of a solar load light source after the lithium battery temperature-internal resistance coupling analysis is qualified, and whether adaptive adjustment of discharging power is needed is judged based on the acquired output power-load adaptability monitoring result; the adaptive adjustment of the discharging power is used for improving the stability of the solar street lamp load work and the adaptability of the lithium battery discharging capacity under a low temperature scene. The solar street lamp control stability monitoring module is used for solar street lamp control stability evaluation for evaluating the continuous stability of the solar street lamp night work after the output power-load adaptability monitoring is qualified, and whether multi-level protection coordination is needed is judged based on the acquired solar street lamp control stability evaluation result; the multi-level protection coordination is used for improving the charging and discharging control stability under a low temperature. The specific process of the multi-level protection coordination is as follows: A control stability deviation value for evaluating the continuous stability degree of the overall control logic of the solar street lamp is acquired. The specific process of the grading protection discrimination for improving the overall control stability of the solar street lamp under a low temperature environment is as follows: Whether the control stability deviation value meets the delay confirmation protection condition is judged, if yes, the delay confirmation protection for preventing system misoperation caused by instantaneous interference is started; otherwise, whether the control stability deviation value meets the grading load reduction protection condition is judged, if yes, the grading load reduction protection for avoiding deep discharging of the lithium battery or circuit overload caused by too high load is started, otherwise, the solar street lamp intelligent charging and discharging is continuously executed, and the basic coupling parameters are continuously monitored. The delay confirmation protection condition means that the control stability deviation value is greater than a preset first-level protection threshold value and smaller than a preset second-level protection threshold value. The grading load reduction protection condition means that the control stability deviation value is greater than the preset second-level protection threshold value. The specific process of the delay confirmation protection is as follows: a delay confirmation timer is started, the time length during which the control stability deviation value meets the delay confirmation protection condition is continuously monitored, whether the delay confirmation timer monitoring value is greater than a preset protection trigger threshold value is judged, if yes, the grading load reduction protection is started, otherwise, the solar street lamp intelligent charging and discharging is continuously executed, and the monitoring is continuously performed. The specific process of the lithium battery temperature-internal resistance coupling analysis is as follows: ​ 2. The intelligent charge-discharge control system for lithium batteries of solar street lamps according to claim 1, characterized in that, ​ acquire a basic coupling parameter, the basic coupling parameter including a lithium battery temperature variation coefficient for quantifying a degree of temperature fluctuation of the lithium battery in a low-temperature environment and a lithium battery internal resistance variation coefficient for quantifying a range of variation of the internal resistance of the lithium battery with temperature in the low-temperature environment; determine whether the basic coupling parameter meets a lithium battery temperature and internal resistance collaborative variation condition, if yes, acquire a temperature-internal resistance correlation degree evaluation index for evaluating a degree of influence of temperature and internal resistance variation of the lithium battery on the charging and discharging performance in the low-temperature environment, and if not, continue to perform intelligent charging and discharging of the solar street lamp and continuously monitor the basic coupling parameter; the lithium battery temperature and internal resistance collaborative variation condition indicates that the lithium battery temperature variation coefficient is greater than 0 and the lithium battery internal resistance variation coefficient is greater than 0; the temperature-internal resistance correlation degree evaluation index is represented by a result of harmonic mean processing of the basic coupling parameter and a basic coupling parameter influence value; the basic coupling parameter influence value includes a battery temperature variation influence value for reflecting a degree of influence of the lithium battery temperature variation coefficient on the temperature-internal resistance correlation degree evaluation index and a lithium battery internal resistance variation influence value for reflecting a degree of influence of the lithium battery internal resistance variation coefficient on the temperature-internal resistance correlation degree evaluation index; perform lithium battery temperature-internal resistance coupling state discrimination based on the temperature-internal resistance correlation degree evaluation index. 3.The intelligent charge-discharge control system for lithium batteries of solar street lamps according to claim 2, characterized in that, The lithium battery temperature-internal resistance coupling state discrimination is used to accurately discriminate an abnormal coupling state of the temperature and the internal resistance of the lithium battery in the low-temperature environment, and the specific process is as follows: determine whether the temperature-internal resistance correlation degree evaluation index is greater than a preset coupling threshold, if yes, perform an accumulation operation on a coupling abnormality counter value and a coupling abnormality counter overflow discrimination for reducing temperature and internal resistance coupling abnormality caused by a single or short-term occasional abnormality interference and ensuring accuracy of the coupling abnormality determination, and if not, continue to perform intelligent charging and discharging of the solar street lamp and continuously monitor the basic coupling parameter; The specific process of the coupling abnormality counter overflow discrimination is as follows: determine whether the coupling abnormality counter value is greater than a preset maximum coupling abnormality counter threshold, if yes, perform dynamic regulation of a charging and discharging threshold and reset the coupling abnormality counter value in a next preset coupling analysis time period to an initial value, and if not, continue to perform lithium battery temperature-internal resistance coupling analysis.

4. The intelligent charge-discharge control system for lithium batteries of solar street lamps according to claim 3, characterized in that, The specific process of the dynamic regulation of the charging and discharging threshold is as follows: input the current battery internal resistance into a preset battery charging and discharging capacity estimation model to output a maximum allowed charging current and a maximum allowed continuous discharging current; perform charging stage threshold parameter correction for improving stable adaptation of the charging current to the dynamic performance of the battery, and the specific process is as follows: input the temperature-internal resistance correlation degree evaluation index and the maximum allowed charging current into a preset parameter adjustment strategy mapping table to obtain a charging current adjustment coefficient; use a range corresponding to the charging current adjustment coefficient as an adjustment step length to adjust the upper limit of the charging current in a direction of decreasing the charging current adjustment coefficient. The charging current stability evaluation index is continuously monitored. If the charging current stability evaluation index is less than a preset stability threshold, the discharge phase threshold parameter correction is performed. Otherwise, the charging phase threshold parameter correction is continuously performed. When the number of charging phase threshold parameter correction is greater than a preset maximum number of charging phase threshold parameter correction, if the charging current stability evaluation index is still not less than the preset stability threshold, a charging parameter correction failure warning is sent. The charging current stability evaluation index is represented by the fluctuation amplitude of the charging current in a preset coupling analysis time period.

5. The intelligent charge-discharge control system for lithium batteries of solar street lamps according to claim 4, characterized in that, The discharge phase threshold parameter correction is used to improve the safety and load working stability of the discharge process. The specific process is as follows: It is judged whether the maximum allowed continuous discharge current is greater than the solar load driver rated current. If yes, the output power-load adaptability monitoring is performed. Otherwise, the discharge current upper limit adjustment is performed. The discharge current upper limit adjustment represents that the temperature-internal resistance correlation evaluation index and the maximum allowed continuous discharge current are input into a preset discharge threshold adjustment mapping table for query to obtain a discharge current adjustment coefficient. The amplitude corresponding to the discharge current adjustment coefficient is used as the adjustment step to adjust the solar load driving current upper limit in the direction of reducing the lithium battery discharge current step by step. The load end voltage stability evaluation index is continuously monitored. When the load end voltage stability evaluation index is less than a preset load fluctuation threshold, the output power-load adaptability monitoring is performed. Otherwise, the discharge current upper limit adjustment is continuously performed. When the number of discharge current upper limit adjustment is greater than a preset maximum number of discharge current upper limit adjustment, if the load end voltage stability evaluation index is still not less than the preset stability threshold, a discharge parameter correction failure warning is sent. The load end voltage stability evaluation index is used to quantify the stability of the solar load driver output voltage.

6. The intelligent charge-discharge control system for lithium batteries of solar street lamps according to claim 5, characterized in that, The specific process of the output power-load adaptability monitoring is as follows: An output power adaptability deviation rate for evaluating the adaptability degree of the lithium battery actual output power and the solar load driver load power is obtained. The output power adaptability deviation rate is represented by the deviation quantization result of the lithium battery output power and the solar load driver load power and the proportion quantization result of the solar load driver load power. It is judged whether the output power adaptability deviation rate is less than a preset output power adaptability threshold. If yes, the solar street lamp control stability evaluation is performed. Otherwise, the discharge power self-adaptive adjustment is taken.

7. The intelligent charge-discharge control system for lithium batteries of solar street lamps according to claim 6, characterized in that, The specific process of the discharge power self-adaptive adjustment is as follows: A battery maximum output power for evaluating the adaptability degree of the lithium battery actual output power and the solar load driver load power at low temperature is obtained. The matching operation is performed based on the battery maximum output power. The matching operation is used to obtain a load target power accurately matched with the current battery power supply capacity. The output power of the solar load driver is adjusted to the load target power. After the discharge power self-adaptive adjustment is completed, the output power adaptability deviation rate is re-obtained. If the output power adaptability deviation rate is still not less than the preset output power adaptability threshold, a discharge power adjustment failure warning is sent. Otherwise, the solar street lamp control stability evaluation is performed. 8.The intelligent charge-discharge control system for lithium battery of solar street lamp according to claim 6, characterized in that, The specific process of the solar street lamp control stability evaluation is as follows: Obtain the control stability quantitative parameter; The control stability quantitative parameter includes a lithium battery output power stability evaluation index for quantifying the fluctuation degree of the lithium battery output power, a load end voltage stability index for reflecting the deviation of the load end voltage from the rated voltage, and a lithium battery temperature influence index for embodying the interference degree of temperature change on the lithium battery performance and system control stability; The result of the weighting and coupling processing of the control stability quantitative parameter and the corresponding control stability influence parameter is used as the solar street lamp control stability evaluation index for evaluating the overall control stability degree of the solar street lamp and identifying the risk of flash and power failure in advance; The control stability influence parameter includes a lithium battery output power influence factor for reflecting the influence degree of the lithium battery output power stability evaluation index on the solar street lamp control stability evaluation index, a load end voltage influence factor for reflecting the influence degree of the load end voltage stability index on the solar street lamp control stability evaluation index, and a lithium battery temperature influence factor for reflecting the influence degree of the lithium battery temperature influence index on the solar street lamp control stability evaluation index; Determine whether the solar street lamp control stability evaluation index is greater than the preset control stability threshold value, if yes, continue to perform the solar street lamp intelligent charging and discharging, and continuously monitor the basic coupling parameter, otherwise, perform multi-level protection coordination. 9.The intelligent charge-discharge control system for lithium battery of solar street lamp according to claim 1, characterized in that, The specific process of the hierarchical load shedding protection is as follows: Based on the input control stability deviation value, perform load driver load shedding amplitude calculation; The load driver load shedding amplitude calculation represents the solar load driver load shedding ratio for improving the adaptability of the load power to the current discharging capacity of the lithium battery and reducing the control stability deviation; Determine whether the solar load driver load shedding ratio is greater than the preset maximum load shedding threshold value, if yes, set the solar load driver load shedding ratio to the preset maximum load shedding threshold value, otherwise, couple the solar load driver load shedding ratio with the solar load driver load power, obtain the corresponding power adjustment instruction and send it to the charging and discharging control center, and adjust the output current reference of the solar load driver based on the function adjustment instruction; Continuously monitor the solar street lamp control stability evaluation index, when the solar street lamp control stability evaluation index is greater than the preset control stability threshold value, continue to perform the solar street lamp intelligent charging and discharging, and continuously monitor the basic coupling parameter, otherwise, send a hierarchical load shedding protection failure warning.

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