A charge-discharge integrated management system and method based on a photovoltaic energy storage charging station

Abstract

The application belongs to the technical field of charge and discharge management, and discloses a charge and discharge integrated management system and method based on a photovoltaic energy storage charging station, which comprises a voltage reference module, which is used for collecting a DC bus voltage, matching the DC bus voltage with a preset voltage interval, determining a converter response direction, generating default response power of each converter as a reference power; a capacity reconstruction module, which is used for obtaining equivalent cycle times, internal resistance change proportions and open circuit voltage recovery characteristics of an energy storage battery cluster, determining a battery cluster attenuation state, and correcting preset state of charge upper and lower boundaries and charge and discharge rate upper limits to obtain dynamic available capacity boundaries and power upper limits of the battery cluster; and a power generation module, which is used for generating power scheduling instructions for photovoltaic and energy storage battery cluster charging and discharging under the constraints of dynamic available capacity boundaries and power upper limits of the battery cluster in combination with the reference power; and the application improves power utilization rate and charge and discharge management accuracy of the charging station.

Description

Technical Field

[0001] This invention relates to the field of charge and discharge management technology, and more specifically, to an integrated charge and discharge management system and method based on a photovoltaic energy storage charging station. Background Technology

[0002] With the development of smart grid technology, charging stations integrating photovoltaic power generation, energy storage systems, and electric vehicle charging facilities have become an important way to improve the self-sufficiency of power distribution networks. Existing charging and discharging management solutions for such charging stations have the following problems: The upper and lower boundaries of the state of charge and the upper limit of the charge / discharge rate of the energy storage battery cluster are set by the fixed parameters at the battery factory and remain unchanged throughout the entire operating cycle, which cannot reflect the aging and degradation of the battery cluster. Determining whether an energy storage battery cluster has the ability to charge and discharge depends solely on the single parameter of state of charge. This parameter only reflects the proportion of remaining capacity and cannot reflect the actual safety tolerance of the battery after aging. After long-term use, the internal resistance of the battery increases and polarization intensifies. If the battery is still scheduled according to the factory parameters, the depth of charge or discharge rate may exceed the current actual safety tolerance range of the battery. Long-term operation will accelerate battery degradation and may even pose safety hazards such as thermal runaway. After determining the current available capacity of the energy storage battery cluster, all the capacity is directly put into daily charging and discharging scheduling without reserving capacity in layers for different uses. When the charging station faces three types of capacity demands at the same time—emergency support, grid-side scheduling, and daily vehicle charging and discharging—it is difficult to reasonably balance them. This can easily lead to a situation where the capacity for one purpose is over-occupied, and there is no capacity available for the other needs. The power response of each converter on the DC bus side depends on the real-time communication commands from the dispatch center. When communication is delayed or interrupted for a short time, each converter cannot independently determine its basic response behavior based on its own state, which can easily cause power response lag during communication anomalies.

[0003] In view of this, the present invention proposes an integrated charging and discharging management system and method based on photovoltaic energy storage charging stations to solve the above problems. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art and to achieve the above objectives, the present invention provides the following technical solution: an integrated charging and discharging management system based on a photovoltaic energy storage charging station, comprising: The voltage reference module is used to acquire the DC bus voltage, match the DC bus voltage with a preset voltage range, determine the converter response direction, and generate the default response power of each converter as the reference power. The capacity reconfiguration module is used to obtain the equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristics of the energy storage battery cluster, determine the battery cluster degradation state, and correct the preset upper and lower boundaries of the state of charge and the upper limit of the charge and discharge rate to obtain the dynamic available capacity boundary and power upper limit of the battery cluster. The power generation module is used to generate power scheduling instructions for charging and discharging photovoltaic and energy storage battery clusters, based on the dynamic available capacity boundary and power upper limit constraints of the battery cluster and the reference power. The capacity reservation module is used to divide the emergency backup capacity, power grid response capacity and free dispatch capacity within the dynamic available capacity boundary, and to determine the free dispatch capacity as the callable capacity; The application scheduling module is used to allocate charging and discharging power to each charging pile in the charging station according to the power scheduling instructions, within the range of available capacity.

[0005] Preferably, determining the converter response direction includes: The DC bus voltage is compared with a first voltage threshold and a second voltage threshold in a preset voltage range, and the converter response direction is determined based on the position of the DC bus voltage relative to the first voltage threshold and the second voltage threshold. When the DC bus voltage is less than the first voltage threshold in the preset voltage range, the converter is determined to execute the first response direction. When the DC bus voltage is greater than the second voltage threshold in the preset voltage range, the converter is determined to execute the second response direction. When the DC bus voltage is between the first voltage threshold and the second voltage threshold, the current response direction of the converter is maintained.

[0006] Preferably, the reference power includes: The corresponding power response range is determined based on the preset voltage range where the DC bus voltage is located, and the default response power of the converter is determined according to the position of the DC bus voltage in the corresponding power response range. The default response power of each converter is associated according to the converter type and response direction to form a reference power.

[0007] Preferably, determining the battery cluster degradation state includes: The actual cumulative equivalent cycle count, internal resistance change ratio relative to the initial internal resistance, and open-circuit voltage recovery characteristics corresponding to the most recent resting relaxation process of the energy storage battery cluster are obtained according to a preset period. The equivalent cycle count, internal resistance change ratio, and open-circuit voltage recovery characteristics are compared with the corresponding attenuation judgment conditions, and the attenuation state of the battery cluster is determined based on the comparison results.

[0008] Preferably, the preset state of charge upper and lower boundaries include the preset state of charge upper boundary and the preset state of charge lower boundary corresponding to the condition when the battery cluster has not degraded; the upper limit of the charge / discharge rate is the upper limit of the rated charge / discharge rate; Based on the battery cluster's degradation state, the upper and lower boundaries of the preset state of charge and the lower boundary of the preset state of charge are corrected in opposite directions, and the upper limit of the rated charge-discharge rate is reduced according to the internal resistance change ratio, so that the corrected upper and lower boundaries of the state of charge and the upper limit of the charge-discharge rate correspond to the current degradation state of the battery cluster.

[0009] Preferably, obtaining the dynamic available capacity boundary and power upper limit of the battery cluster includes: The corrected upper boundary of the state of charge and the lower boundary of the state of charge are determined as the dynamic available capacity boundary corresponding to the current operating cycle of the battery cluster. The corrected upper limit of the charge / discharge rate is matched with the rated capacity of the battery cluster to obtain the upper limit of the power corresponding to the current operating cycle. The dynamic available capacity boundary and the upper limit of the power are updated based on the subsequently obtained equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristic change.

[0010] Preferably, the power scheduling instructions for generating photovoltaic and energy storage battery cluster charging and discharging include: The direction of photovoltaic power adjustment and the direction of charging or discharging of energy storage battery clusters are determined based on the reference power. The charging and discharging power of energy storage battery clusters is determined according to the power difference between photovoltaic output power and charging station power demand, so that the charging and discharging power of energy storage battery clusters does not exceed the power upper limit and the state of charge of energy storage battery clusters is within the dynamic available capacity boundary, and corresponding power dispatch instructions are generated.

[0011] Preferably, determining the free scheduling capacity as the callable capacity includes: Based on the total capacity corresponding to the dynamic available capacity boundary, the emergency backup capacity, grid response capacity, and free dispatch capacity are divided in sequence. The remaining capacity after the emergency backup capacity and grid response capacity are reserved is determined as the free dispatch capacity, and the free dispatch capacity is used as the callable capacity when the energy storage battery cluster participates in the power regulation of the charging pile.

[0012] Preferably, the allocation of charging and discharging power to each charging pile within the charging station includes: Obtain the charging and discharging power demand corresponding to each charging pile, determine the power allocation relationship corresponding to each charging pile according to the power scheduling instruction, determine the allocated charging and discharging power based on the charging and discharging power demand corresponding to each charging pile, so that the sum of the power call amount of the energy storage battery cluster corresponding to each charging pile does not exceed the callable capacity, and the allocated charging and discharging power of each charging pile does not exceed the power corresponding to the power scheduling instruction.

[0013] A charging and discharging integrated management method based on photovoltaic energy storage charging stations includes: S1. Acquire the DC bus voltage, match the DC bus voltage with the preset voltage range, determine the converter response direction, and generate the default response power of each converter as the reference power; S2. Obtain the equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristics of the energy storage battery cluster, determine the battery cluster decay state, and correct the preset upper and lower boundaries of the state of charge and the upper limit of the charge and discharge rate to obtain the dynamic available capacity boundary and power upper limit of the battery cluster. S3. Under the constraints of the dynamic available capacity boundary and power upper limit of the battery cluster, and in combination with the reference power, generate power dispatch instructions for charging and discharging of photovoltaic and energy storage battery clusters. S4. Divide the emergency backup capacity, power grid response capacity and free dispatch capacity within the dynamic available capacity boundary, and determine the free dispatch capacity as the callable capacity; S5. According to the power scheduling instruction, allocate charging and discharging power to each charging pile in the charging station within the range of available capacity.

[0014] Compared with the prior art, the present invention has the following beneficial effects: By collecting DC bus voltage and matching it with a preset voltage range, each converter can independently determine its basic response direction and default response power based on locally collected voltage information, forming a reference power. This avoids the converter power response relying entirely on real-time communication commands continuously issued by the dispatch center, reducing the risk of power response lag during communication anomalies. The equivalent cycle count, internal resistance change ratio, and open-circuit voltage recovery characteristics of the energy storage battery cluster are acquired to comprehensively determine the current degradation state of the battery cluster. Based on this, the preset upper and lower boundaries of the state of charge and the upper limit of the charge / discharge rate are adjusted accordingly, resulting in a dynamic available capacity boundary and power limit that matches the current actual safety capability of the battery cluster. This avoids the problems in existing solutions where using factory-fixed boundary parameters without considering the actual aging of the batteries leads to dispatch commands exceeding the battery's safety tolerance or the battery's available capacity not being fully utilized. Simultaneously, the dynamic available capacity boundary and power limit are periodically updated based on continuously acquired aging characteristic parameters, allowing the boundary to continuously adjust dynamically according to the actual degradation process of the battery cluster.

[0015] Under the constraints of the dynamic available capacity boundary and power upper limit of the battery cluster, power dispatch instructions for charging and discharging of photovoltaic and energy storage battery clusters are generated by combining the reference power. This ensures that the generation process of power dispatch instructions simultaneously considers both the basic response requirements on the bus side and the current actual safety tolerance of the battery cluster. Within the dynamic available capacity boundary, emergency backup capacity, grid response capacity, and free dispatch capacity are sequentially divided, with the free dispatch capacity defined as the callable capacity. This allows for a reasonable differentiation of the available capacity of the same energy storage battery cluster among three different uses: equipment emergency backup, grid negotiation response, and daily charging and discharging dispatch within the station. This avoids the problem in existing schemes where the entire capacity is directly allocated to a single use, resulting in insufficient capacity support for other uses. According to the power dispatch instructions, charging and discharging power is allocated to each charging pile within the charging station within the callable capacity range. This ensures that the charging and discharging power allocation results obtained by each charging pile meet both the total amount constraint of the power dispatch instructions and the callable capacity range determined after capacity stratification and reservation. This achieves a reasonable allocation of charging and discharging resources under the dual constraints of the actual safety capability of the energy storage battery and the multi-purpose capacity division. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the integrated charging and discharging management system based on a photovoltaic energy storage charging station according to the present invention. Figure 2 This is a schematic diagram of a charging and discharging integrated management method based on a photovoltaic energy storage charging station according to the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0018] Please see Figure 1 As shown, this embodiment provides an integrated charging and discharging management system based on a photovoltaic energy storage charging station, which specifically includes the following steps: The voltage reference module is used to acquire the DC bus voltage, match the DC bus voltage with a preset voltage range, determine the converter response direction, and generate the default response power of each converter as the reference power. The capacity reconfiguration module is used to obtain the equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristics of the energy storage battery cluster, determine the battery cluster degradation state, and correct the preset upper and lower boundaries of the state of charge and the upper limit of the charge and discharge rate to obtain the dynamic available capacity boundary and power upper limit of the battery cluster. The power generation module is used to generate power scheduling instructions for charging and discharging photovoltaic and energy storage battery clusters, based on the dynamic available capacity boundary and power upper limit constraints of the battery cluster and the reference power. The capacity reservation module is used to divide the emergency backup capacity, power grid response capacity and free dispatch capacity within the dynamic available capacity boundary, and to determine the free dispatch capacity as the callable capacity; The application scheduling module is used to allocate charging and discharging power to each charging pile in the charging station according to power scheduling instructions, within the range of available capacity. The modules are connected via wired and / or wireless means to achieve data transmission between them.

[0019] Determining the converter response direction includes: The DC bus voltage is compared with a first voltage threshold and a second voltage threshold in a preset voltage range, and the converter response direction is determined based on the position of the DC bus voltage relative to the first voltage threshold and the second voltage threshold. When the DC bus voltage is less than the first voltage threshold in the preset voltage range, the converter is determined to execute the first response direction. When the DC bus voltage is greater than the second voltage threshold in the preset voltage range, the converter is determined to execute the second response direction. When the DC bus voltage is between the first voltage threshold and the second voltage threshold, the current response direction of the converter is maintained.

[0020] In this embodiment, it should be noted that the first voltage threshold and the second voltage threshold are preset based on the rated voltage of the DC bus of the charging station and the allowable normal fluctuation range on the bus side. The specific setting method includes: obtaining the rated voltage value of the DC bus and the maximum voltage deviation ratio that the converter and line devices on the bus side can withstand; determining the value obtained by subtracting the first preset deviation ratio from the rated voltage as the first voltage threshold, and determining the value obtained by adding the second preset deviation ratio to the rated voltage as the second voltage threshold, so that the first voltage threshold and the second voltage threshold correspond to the critical points when the bus voltage deviates downward and upward from the rated voltage, respectively, and the converter needs to start performing power response actions.

[0021] It should be noted that the specific values ​​of the first preset offset ratio and the second preset offset ratio are determined comprehensively based on the normal operating voltage range specified in the instruction manual of the converter equipment in the charging station and the allowable voltage fluctuation margin on the bus side. They are usually selected within the range of 1% to 3% of the rated voltage. The first preset offset ratio and the second preset offset ratio can be the same, or they can be set separately according to the actual difference between the upward and downward adjustment margins on the bus side.

[0022] For example, if the rated voltage of the DC bus of a charging station is set to 750V, and the allowable normal voltage fluctuation range of the converter equipment on the bus side is ±2% of the rated voltage, then the first preset offset ratio is set to 2%, and the first voltage threshold U1 is calculated as 750V × (1 − 2%) = 735V; the second preset offset ratio is set to 2%, and the second voltage threshold U2 is calculated as 750V × (1 + 2%) = 765V. If, during actual operation of the charging station, a large margin is required for the downward fluctuation of the bus voltage, the first preset offset ratio can be adjusted to 2.5%. In this case, the first voltage threshold is adjusted accordingly to U1 = 750V × (1 − 2.5%) = 731.25V, while the second voltage threshold remains unchanged at 765V.

[0023] It should be noted that the DC bus voltage reflects the instantaneous balance of power supply and demand within the charging station: when the bus voltage is low, it indicates a power deficit on the bus side. In this case, the energy storage battery clusters should be controlled to discharge, and the photovoltaic units should be controlled to maintain maximum power output, i.e., the first response direction should be executed. When the bus voltage is high, it indicates a power surplus on the bus side. In this case, the photovoltaic units should be controlled to reduce output, and the energy storage battery clusters should be controlled to charge, i.e., the second response direction should be executed. When the bus voltage is between the two thresholds, it indicates that the current power supply and demand are basically balanced, and each converter maintains its original response direction without switching. The first voltage threshold and the second voltage threshold together constitute a preset voltage range. The first voltage threshold is used to determine that the DC bus voltage is in the first response region, and the second voltage threshold is used to determine that the DC bus voltage is in the second response region.

[0024] Here's an example: Let's set the rated DC bus voltage to 750V, the first voltage threshold to 735V, and the second voltage threshold to 765V. If the DC bus voltage measured at a certain moment is 728V, which is less than the first voltage threshold of 735V, the converter should execute the first response direction, i.e., control the energy storage battery cluster to switch to a discharging response and the photovoltaic unit to maintain maximum power point tracking. If the DC bus voltage measured at another moment is 772V, which is greater than the second voltage threshold of 765V, the converter should execute the second response direction, i.e., control the photovoltaic unit to reduce its output and the energy storage battery cluster to switch to a charging response. If the measured DC bus voltage is 748V, which is between 735V and 765V, then the current response direction of each converter remains unchanged.

[0025] The reference power includes: The corresponding power response range is determined based on the preset voltage range where the DC bus voltage is located, and the default response power of the converter is determined according to the position of the DC bus voltage in the corresponding power response range. The default response power of each converter is associated according to the converter type and response direction to form a reference power.

[0026] Specifically, several power response sub-intervals are further divided below the first voltage threshold and above the second voltage threshold. Each sub-interval corresponds to a preset default response power ratio. The further the DC bus voltage deviates from the rated voltage, the larger the corresponding default response power ratio. For each converter connected to the DC bus in the charging station, a converter type identifier is pre-assigned to each converter to distinguish whether it is a photovoltaic converter or an energy storage converter. Each converter calculates its own default response power value according to its own type's preset rated power and the found default response power ratio, and labels the value with the converter type identifier and the current response direction identifier. The labeled default response power of each converter is classified according to the converter type. If there are multiple converters of the same type with the same response direction identifier, their default response power is summed to obtain the total default response power of that type of converter. The total default response power of the photovoltaic type and the total default response power of the energy storage type are arranged and combined according to their respective response direction identifiers to form the base power corresponding to the current scheduling cycle.

[0027] It should be noted that by integrating the process of determining the default response power value with the process of associating type and direction identifiers, the reference power is no longer a single power value. For example, suppose a charging station's DC bus is connected to three converters: one photovoltaic converter, numbered PV1, with a rated power of 100kW; and two energy storage converters, numbered BAT1 and BAT2, each with a rated power of 100kW. The first voltage threshold is set to 735V, and below 735V, it is further divided into two sub-intervals: 728V to 735V is the first sub-interval, corresponding to a default response power ratio of 60% of the rated power; below 728V is the second sub-interval, corresponding to a default response power ratio of 100% of the rated power.

[0028] At a certain sampling moment, the DC bus voltage was measured to be 728V, which is lower than the first voltage threshold of 735V and falls within the boundary of the first sub-interval. Based on the aforementioned method, it was determined that each converter would execute the first response direction, i.e., energy storage would switch to discharging, and photovoltaics would maintain maximum power point tracking (the default response power ratio of photovoltaics in the first response direction is set to 0%, and no additional output adjustment is made). The default response power of each converter was calculated as follows: the default response power of photovoltaic converter PV1 is 100kW × 0% = 0kW; the default response power of energy storage converter BAT1 is 100kW × 60% = 60kW; and the default response power of energy storage converter BAT2 is 100kW × 60% = 60kW.

[0029] Labeling the above three default response powers with converter type and response direction identifiers respectively, we can obtain: (PV1, photovoltaic type, orientation: none, power: 0kW); (BAT1, energy storage type, direction: discharge, power: 60kW); (BAT2, energy storage type, direction: discharge, power: 60kW).

[0030] Since BAT1 and BAT2 belong to the same energy storage type and have the same response direction identifier (discharge direction), the default response power of the two is summed to obtain a total default response power of 60kW + 60kW = 120kW for the energy storage type, with the direction identifier being discharge; the total default response power of the photovoltaic type remains 0kW.

[0031] The total default response power of photovoltaic type and the total default response power of energy storage type are arranged and combined according to their respective direction indicators to form the reference power corresponding to this scheduling cycle, which is expressed as: Reference power = {Photovoltaic type: 0kW (no direction); Energy storage type: 120kW (discharge direction)}. This structured reference power is then output to the power generation module, and can be directly used as a reference for generating energy storage battery cluster charging and discharging power scheduling instructions based on the 120kW discharge direction value corresponding to the energy storage type.

[0032] Determining the battery cluster degradation status includes: The actual cumulative equivalent cycle count, internal resistance change ratio relative to the initial internal resistance, and open-circuit voltage recovery characteristics corresponding to the most recent resting relaxation process of the energy storage battery cluster are obtained according to a preset period. The equivalent cycle count, internal resistance change ratio, and open-circuit voltage recovery characteristics are compared with the corresponding attenuation judgment conditions, and the attenuation state of the battery cluster is determined based on the comparison results.

[0033] In this embodiment, it should be noted that the equivalent cycle count is used to reflect the cumulative usage of the battery cluster. The battery management system continuously accumulates and records the discharge depth corresponding to each charge-discharge process of the battery cluster. Multiple charge-discharge processes with different discharge depths are converted into equivalent complete cycle counts according to the discharge depth ratio and summed to obtain the actual cumulative equivalent cycle count of the battery cluster. For example, if the battery cluster experiences three charge-discharge processes in a certain statistical period, with discharge depths of 100%, 50%, and 30% respectively, according to the equivalent conversion rules, a cycle with a 50% discharge depth is converted into 0.5 equivalent cycles, and a cycle with a 30% discharge depth is converted into 0.3 equivalent cycles. Therefore, the newly added equivalent cycle count in this period is 1 + 0.5 + 0.3 = 1.8 times. This is added to the previously recorded equivalent cycle count to obtain the current actual cumulative equivalent cycle count of the battery cluster.

[0034] The internal resistance change ratio reflects the increase in the battery's internal ohmic resistance and polarization resistance. Within each preset cycle, the instantaneous voltage drop is measured under the same current step conditions (i.e., the same discharge current abrupt change amplitude). The current internal resistance value of the battery cluster is calculated using Ohm's law and compared with the initial internal resistance value recorded under the same test conditions at the time of manufacture. The internal resistance change ratio can be expressed as: ;in, Indicates the percentage change in internal resistance; Indicates the current running cycle The obtained internal resistance of the energy storage battery cluster; This represents the initial internal resistance of the energy storage battery cluster. The initial internal resistance was measured at the factory under a test condition where the discharge current suddenly increased by 20A. The internal resistance is 5mΩ; this was measured under the same 20A current surge condition during this cycle, corresponding to the instantaneous voltage drop. The Ω value is 5.9 mΩ. Substituting this into the formula, we can calculate: This means that the change in internal resistance of the battery cluster in this cycle is 18%.

[0035] The degradation criteria for the internal resistance change ratio are set as follows: less than 10% is considered no significant degradation, 10% to 25% is considered mild degradation, 25% to 40% is considered moderate degradation, and greater than 40% is considered severe degradation. The open-circuit voltage recovery rate criteria are set as follows: when the recovery rate is lower than a preset rate threshold, the battery's internal polarization recovery capability is considered to have decreased, serving as the basis for adjusting the degradation level by one grade. For example, an energy storage battery cluster undergoes parameter collection at a preset cycle (e.g., every 30 days). This collection yields an equivalent cycle count of 3200, with an internal resistance change ratio relative to the initial internal resistance of 18%. The open-circuit voltage recovery rate is not lower than the preset rate threshold. Based on the criteria, 18% falls within the 10% to 25% range, indicating the battery cluster is currently in a mild degradation state. Since the open-circuit voltage recovery rate is normal, no degradation level adjustment is triggered, and the battery cluster's degradation state for this cycle is ultimately determined to be mild degradation.

[0036] It should be noted that the resting relaxation process refers to the process after a battery cluster has completed a charging or discharging operation, during which no active charging or discharging operations are performed on it. The battery is kept in an open-circuit resting state for a period of time, allowing the concentration polarization and electrochemical polarization effects generated during the charging and discharging process to gradually dissipate. The battery terminal voltage gradually rises or falls from the instantaneous voltage at the end of the charging or discharging process to a stable voltage value when the internal reaction reaches a relatively balanced state. This continuous process of the voltage gradually stabilizing is the resting relaxation process, and the terminal voltage measured during this process is called the open-circuit voltage.

[0037] The specific method for obtaining the open-circuit voltage recovery characteristics is as follows: During the rest period after the end of the current charge and discharge operation of the battery cluster, the terminal voltage value of the battery cluster is continuously recorded at a fixed sampling interval to obtain the recovery curve of the terminal voltage changing with the rest time. The time taken for the terminal voltage to recover to the preset stability judgment condition (e.g., the voltage change amplitude within two adjacent sampling intervals is less than the preset change amplitude) and the average voltage recovery amplitude per unit time during the recovery process are extracted from the curve. These are respectively used as the open-circuit voltage recovery time and the open-circuit voltage recovery rate, which together constitute the open-circuit voltage recovery characteristics.

[0038] For example, after a battery cluster completes one discharge cycle, the instantaneous terminal voltage reading is 3.35V. After entering the resting relaxation process, continuous sampling is performed at intervals of once per minute: 3.42V is measured at the 1st minute, 3.48V at the 3rd minute, 3.51V at the 6th minute, 3.515V at the 10th minute, and 3.516V at the 12th minute. After that, the voltage change amplitude of two consecutive samplings is less than the preset change amplitude of 0.002V, indicating that the battery has recovered to a stable state, and the open circuit voltage recovery time is determined to be 12 minutes. Dividing the total voltage recovery amount (3.516V − 3.35V) = 0.166V by the recovery time of 12 minutes, the open circuit voltage recovery rate is approximately 0.0138V / minute. The recovery time and recovery rate are compared with the recovery time and recovery rate range under the historical normal state of this battery cluster. If the recovery time is significantly longer than the historical normal range and the recovery rate is significantly lower than the historical normal range, it is determined that the internal polarization recovery capability of the battery cluster has decreased, which serves as one of the auxiliary correction bases for determining the battery cluster's degradation state.

[0039] The preset state of charge upper and lower boundaries include the preset state of charge upper boundary and the preset state of charge lower boundary corresponding to when the battery cluster has not degraded; the upper limit of the charge / discharge rate is the upper limit of the rated charge / discharge rate. Based on the battery cluster's degradation state, the upper and lower boundaries of the preset state of charge and the lower boundary of the preset state of charge are corrected in opposite directions, and the upper limit of the rated charge-discharge rate is reduced according to the internal resistance change ratio, so that the corrected upper and lower boundaries of the state of charge and the upper limit of the charge-discharge rate correspond to the current degradation state of the battery cluster.

[0040] Specifically, the formula for correcting the upper boundary of the charged state is: ;in, Indicates the battery cluster in the first The upper boundary of the corrected charged state corresponding to each correction cycle; This indicates the upper boundary of the preset state of charge when the battery cluster has not degraded; This represents the correction factor indicating the proportional contraction of the upper boundary as the internal resistance changes; Indicates the first The percentage change in the internal resistance of the battery cluster obtained from each correction cycle. This represents the correction factor for the shrinkage of the upper boundary as a percentage of the number of iterations. Indicates the first The actual cumulative equivalent number of cycles for each battery cluster corresponding to each correction cycle; This indicates the number of cycles corresponding to the design life of the battery cluster; An index identifier indicating the correction period; The boundary correction formula for the charged state is: ;in, This represents the boundary under the corrected charged state; This represents the boundary of the preset charged state when the battery cluster has not experienced degradation. This represents the correction factor that shifts the lower boundary upward proportionally with changes in internal resistance. Simultaneously, the maximum allowable charge / discharge rate at that moment is synchronously reduced based on the proportion of internal resistance increase. The formula for correcting the upper limit of the charge / discharge rate is as follows: ;in, This indicates the upper limit of the charge / discharge rate allowed in the current cycle after correction; Indicates the rated charge / discharge rate of the battery cluster; This represents the correction factor for the proportional contraction of the multiplier as the internal resistance changes.

[0041] It should be noted that, based on the aforementioned criteria for determining the proportion of internal resistance change, the degradation state of the battery cluster is pre-divided into four levels: no significant degradation, slight degradation, moderate degradation, and severe degradation. Then, for this model of battery cluster, combined with aging characteristic data provided by the battery manufacturer or historical data accumulated through accelerated aging tests on the same batch of battery clusters, the recommended state-of-charge boundary contraction range and charge / discharge rate contraction range for each of the above four degradation levels are determined to ensure the safety of subsequent use of the battery cluster. The recommended contraction range is then compared and converted with the typical internal resistance change ratio and typical cycle count ratio of the battery cluster at the corresponding degradation level to deduce a set of values ​​corresponding to each degradation level. , , , The coefficient values ​​are selected to form four preset coefficient sets, each corresponding to one of the four attenuation levels, and stored in the system's preset parameter table. In actual operation, based on the currently determined battery cluster attenuation level, the corresponding set of coefficient values ​​is directly retrieved from the preset parameter table as the calculation for this cycle. , , , .

[0042] It should be noted that the higher the attenuation level, the larger the values ​​of k1, k2, k3, and ρ in the preset coefficient group should be. This makes the contraction amplitude, upward shift amplitude, and charge / discharge rate contraction amplitude of the charge state boundary increase accordingly with the deepening of the attenuation, ensuring that the boundary correction amplitude matches the actual attenuation degree of the battery cluster.

[0043] For example, for a certain model of lithium iron phosphate battery cluster, based on the aging characteristic data and accelerated aging test data provided by the manufacturer, four sets of coefficients are pre-determined: (No obvious degradation level corresponds to...) 0.05 0.03 0.02 0.2; mild attenuation level corresponds to 0.15 For 0.10, 0.08 It is 0.5; the moderate attenuation level corresponds to 0.30 0.20 0.15 It is 0.8; the severe attenuation level corresponds to 0.45 For 0.30, 0.25 The value is 1.0. When the battery cluster is determined to be in a state of slight degradation during this cycle, the system automatically retrieves a set of coefficients corresponding to the slight degradation level from the preset parameter table, i.e. 0.15 For 0.10, 0.08 The value is 0.5, which is then substituted into the aforementioned boundary correction formula for calculation. If the battery cluster's degradation level is reassessed and rises to moderate degradation in a subsequent cycle, the system will automatically switch to retrieving a set of coefficients corresponding to the moderate degradation level. For 0.30, For 0.20, 0.15 It is set to 0.8, which is used for boundary correction calculation in this cycle to realize automatic switching of the correction coefficient as the attenuation level changes.

[0044] The dynamic available capacity boundary and power limit of the battery cluster are obtained by: The corrected upper boundary of the state of charge and the lower boundary of the state of charge are determined as the dynamic available capacity boundary corresponding to the current operating cycle of the battery cluster. The corrected upper limit of the charge / discharge rate is matched with the rated capacity of the battery cluster to obtain the upper limit of the power corresponding to the current operating cycle. The dynamic available capacity boundary and the upper limit of the power are updated based on the subsequently obtained equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristic change.

[0045] Specifically, the corrected upper and lower bounds of the state of charge are used as the range of the state of charge that the energy storage battery cluster is allowed to operate within the current operating cycle, and the dynamic available capacity boundary is determined by this range of the state of charge.

[0046] For example, if the rated capacity of a battery cluster is 1000kWh, and the current corrected state of charge (SOC) upper limit is 15% and the lower limit is 90%, then the corresponding SOC range is 15% to 90%, and the corresponding usable capacity is: 1000 × (90% - 15%) = 750kWh. Furthermore, by mapping the corrected upper limit of the charge / discharge rate to the rated capacity of the battery cluster, the upper limit of the power is obtained.

[0047] The upper limit of power can be expressed as: ;in, This indicates the maximum power limit corresponding to the current operating cycle; This represents the rated capacity of the energy storage battery cluster. Further, the equivalent cycle count, internal resistance change ratio, and open-circuit voltage recovery characteristics of the energy storage battery cluster are reacquired according to a preset cycle. When these characteristics change, the corresponding degradation state is redefined, and the upper and lower boundaries of the state of charge and the upper limit of the charge / discharge rate are revised, thereby updating the dynamic available capacity boundary and the upper limit of power. For example, if the internal resistance change ratio obtained in the current operating cycle is 20%, and the reacquired internal resistance change ratio after subsequent operation is 25%, and the equivalent cycle count and open-circuit voltage recovery characteristics change simultaneously, then the battery cluster degradation state is redefined based on the updated characteristics, and the upper and lower boundaries of the state of charge and the upper limit of the charge / discharge rate are recalculated, so that subsequent power scheduling adopts the updated dynamic available capacity boundary and the upper limit of power.

[0048] Here's an example: Let's assume the battery cluster has no degradation, with a preset upper boundary of 95% and a preset lower boundary of 10% for the preset state of charge. The rated charge / discharge rate is 1, the rated capacity of the battery cluster is 200kWh, and the designed lifespan is 6000 cycles. For the battery cluster identified as being in a slightly degraded state, the corresponding correction factor is selected: , , , Based on the battery cluster internal resistance change rate of 18% and the actual cumulative equivalent cycle count of 3200 cycles collected in this cycle, the dynamic available capacity boundary corresponding to this operating cycle of the battery cluster is determined to be 11.4% to 87%. The corrected charge / discharge rate of 0.91 is then correlated with the rated capacity of 200 kWh, yielding a power limit of 0.91 × 200 kWh = 182 kW for this cycle. After 30 days, the next preset cycle begins, and the battery cluster internal resistance change rate is re-collected, rising to 22%. The updated dynamic available capacity boundary and power limit are then recalculated.

[0049] The power dispatch instructions for generating photovoltaic and energy storage battery cluster charging and discharging include: The direction of photovoltaic power adjustment and the direction of charging or discharging of energy storage battery clusters are determined based on the reference power. The charging and discharging power of energy storage battery clusters is determined according to the power difference between photovoltaic output power and charging station power demand, so that the charging and discharging power of energy storage battery clusters does not exceed the power upper limit and the state of charge of energy storage battery clusters is within the dynamic available capacity boundary, and corresponding power dispatch instructions are generated.

[0050] Specifically, the current photovoltaic output power and the total power demand of each charging pile in the charging station are obtained. The response direction identifier corresponding to the energy storage type in the reference power is read and the direction identifier is determined as the direction of charging or discharging of the energy storage battery cluster this time. Based on the determination of the direction, the specific charging and discharging power value that the energy storage battery cluster needs to undertake this time is further determined according to the power difference between the photovoltaic output power and the power demand of the charging station.

[0051] Here's an example: using the data from the aforementioned baseline power example, the baseline power determined for this scheduling cycle is {PV type: 0kW (no direction); Energy storage type: 120kW (discharge direction)}. This means the energy storage battery cluster's response direction for this cycle has already been determined by the baseline power to be discharge, eliminating the need for re-determination. At this point, the total current power demand of all charging piles in the charging station is 180kW, and the actual current output power of the PV converter PV1 is 60kW. The power difference between the two is 180kW − 60kW = 120kW. This 120kW is determined as the total power that energy storage battery clusters BAT1 and BAT2 need to handle in the discharge direction.

[0052] Further assessment is needed to determine if the power meets the constraints: The total power limit of the energy storage battery clusters BAT1 and BAT2 is set at 182kW (calculated based on the corrected charge / discharge rate of 0.91C and the total rated capacity of 200kWh in the aforementioned embodiment). The current total state of charge is 60%, and the dynamic available capacity boundary is 11.4% to 87%. Comparison shows that 120kW does not exceed the power limit of 182kW, and the state of charge decrease calculated after discharging 120kW for a certain period still keeps the state of charge above 11.4%, not exceeding the lower limit of the dynamic available capacity boundary. Therefore, a corresponding power scheduling instruction is generated: the energy storage battery clusters discharge a total of 120kW, allocated according to the respective rated capacity proportions of BAT1 and BAT2, with BAT1 undertaking 60kW and BAT2 undertaking 60kW.

[0053] Here's another example: If the response direction identifier for the energy storage type in the base power of a certain scheduling cycle is the charging direction, and the current total power demand of all charging piles in the charging station is 100kW, while the current actual output power of the photovoltaic converter PV1 is 95kW, the photovoltaic output power is greater than the power demand of the charging station, with a power difference of 95kW − 100kW. Since the direction identifier has been determined as the charging direction, the absolute value of the power difference is taken, meaning the energy storage battery cluster needs to handle 5kW in the charging direction. After comparison, 5kW does not exceed the power limit, and the state of charge after charging does not exceed the dynamic available capacity boundary limit of 87%. Therefore, the corresponding power scheduling instruction is generated: charge the energy storage battery cluster 5kW.

[0054] Determining the freely schedulable capacity as callable capacity includes: Based on the total capacity corresponding to the dynamic available capacity boundary, the emergency backup capacity, grid response capacity, and free dispatch capacity are divided in sequence. The remaining capacity after the emergency backup capacity and grid response capacity are reserved is determined as the free dispatch capacity, and the free dispatch capacity is used as the callable capacity when the energy storage battery cluster participates in the power regulation of the charging pile.

[0055] Specifically, within the capacity range corresponding to the dynamic available capacity boundary, emergency backup capacity, grid response capacity, and freely dispatchable capacity are sequentially divided. The emergency backup capacity and grid response capacity are divided according to preset capacity values ​​or corresponding capacity ratios. After completing these two capacity divisions, the remaining capacity is determined as the freely dispatchable capacity. For example, if the dynamic available capacity boundary of a battery cluster is 11.4% to 87%, corresponding to a state of charge range of 75.6%, the equivalent capacity is 200kWh × 75.6% = 151.2kWh. Within this total, 30kWh is reserved for emergency backup capacity and 40kWh for grid response capacity, leaving a remaining capacity of 151.2kWh - 30kWh - 40kWh = 81.2kWh. This 81.2kWh is determined as the available capacity for the battery cluster to participate in charging pile power regulation during this operating cycle.

[0056] Allocating charging and discharging power to each charging pile within the charging station includes: Obtain the charging and discharging power demand corresponding to each charging pile, determine the power allocation relationship corresponding to each charging pile according to the power scheduling instruction, determine the allocated charging and discharging power based on the charging and discharging power demand corresponding to each charging pile, so that the sum of the power call amount of the energy storage battery cluster corresponding to each charging pile does not exceed the callable capacity, and the allocated charging and discharging power of each charging pile does not exceed the power corresponding to the power scheduling instruction.

[0057] In this embodiment, it should be noted that the current charging and discharging power demand of each charging pile in the charging station is obtained, the total power that the energy storage battery cluster can provide to each charging pile is determined according to the power scheduling instruction, and the specific power allocation is determined according to the charging and discharging power demand of each charging pile.

[0058] For example, this power dispatch instruction determines that the battery cluster discharges 110kW. Charging pile 1 requests 60kW and charging pile 2 requests 50kW. The sum of their requests, 110kW, is exactly equal to the 110kW corresponding to the power dispatch instruction. Furthermore, the capacity utilization calculated based on the discharge duration does not exceed the available capacity of 81.2kWh. Therefore, charging pile 1 is allocated 60kW and charging pile 2 is allocated 50kW according to the original requested power value. If the requested power of charging pile 2 is increased to 70kW, making the total demand reach 130kW, which exceeds the 110kW corresponding to the power dispatch instruction, then the 110kW is allocated according to the proportion of the power demand of each charging pile. Charging pile 1 is allocated 110kW×(60 / 130)≈50.8kW, and charging pile 2 is allocated 110kW×(70 / 130)≈59.2kW, ensuring that the total power after allocation does not exceed the value corresponding to the power dispatch instruction. Through the above process, a continuous processing flow is completed, from DC bus voltage response, energy storage battery cluster status correction, photovoltaic and energy storage power scheduling, capacity allocation to charging pile power distribution.

[0059] In this embodiment, by collecting the DC bus voltage and matching it with a preset voltage range, each converter can independently determine its basic response direction and default response power based on the locally collected voltage information, forming a reference power. This avoids the converter power response relying entirely on the dispatch center's continuous real-time communication commands, reducing the risk of power response lag during communication anomalies. The equivalent cycle count, internal resistance change ratio, and open-circuit voltage recovery characteristics of the energy storage battery cluster are acquired to comprehensively determine the current degradation state of the battery cluster. Based on this, the preset upper and lower boundaries of the state of charge and the upper limit of the charge / discharge rate are adjusted accordingly, resulting in a dynamic available capacity boundary and power upper limit that match the current actual safety capability of the battery cluster. This avoids the problems in existing solutions where using factory-fixed boundary parameters without considering the actual aging of the batteries leads to dispatch commands exceeding the battery's safety tolerance or the battery's available capacity not being fully utilized. Simultaneously, the dynamic available capacity boundary and power upper limit are periodically updated based on subsequently acquired aging characteristic parameters, allowing the boundary to continuously adjust dynamically according to the actual degradation process of the battery cluster.

[0060] Under the constraints of the dynamic available capacity boundary and power upper limit of the battery cluster, power dispatch instructions for charging and discharging of photovoltaic and energy storage battery clusters are generated by combining the reference power. This ensures that the generation process of power dispatch instructions simultaneously considers both the basic response requirements on the bus side and the current actual safety tolerance of the battery cluster. Within the dynamic available capacity boundary, emergency backup capacity, grid response capacity, and free dispatch capacity are sequentially divided, with the free dispatch capacity defined as the callable capacity. This allows for a reasonable differentiation of the available capacity of the same energy storage battery cluster among three different uses: equipment emergency backup, grid negotiation response, and daily charging and discharging dispatch within the station. This avoids the problem in existing schemes where the entire capacity is directly allocated to a single use, resulting in insufficient capacity support for other uses. According to the power dispatch instructions, charging and discharging power is allocated to each charging pile within the charging station within the callable capacity range. This ensures that the charging and discharging power allocation results obtained by each charging pile meet both the total amount constraint of the power dispatch instructions and the callable capacity range determined after capacity stratification and reservation. This achieves a reasonable allocation of charging and discharging resources under the dual constraints of the actual safety capability of the energy storage battery and the multi-purpose capacity division. Example

[0061] Please see Figure 2 As shown, parts not described in detail in this embodiment are described in Embodiment 1. A method for integrated charging and discharging management based on a photovoltaic energy storage charging station is provided, including: S1. Acquire the DC bus voltage, match the DC bus voltage with the preset voltage range, determine the converter response direction, and generate the default response power of each converter as the reference power; S2. Obtain the equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristics of the energy storage battery cluster, determine the battery cluster decay state, and correct the preset upper and lower boundaries of the state of charge and the upper limit of the charge and discharge rate to obtain the dynamic available capacity boundary and power upper limit of the battery cluster. S3. Under the constraints of the dynamic available capacity boundary and power upper limit of the battery cluster, and in combination with the reference power, generate power dispatch instructions for charging and discharging of photovoltaic and energy storage battery clusters. S4. Divide the emergency backup capacity, power grid response capacity and free dispatch capacity within the dynamic available capacity boundary, and determine the free dispatch capacity as the callable capacity; S5. According to the power scheduling instruction, allocate charging and discharging power to each charging pile in the charging station within the range of available capacity. Example

[0062] This embodiment discloses an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the operation mode of the above-described integrated charging and discharging management system based on a photovoltaic energy storage charging station.

[0063] Since the electronic device described in this embodiment is the electronic device used to implement the integrated charging and discharging management system and method based on a photovoltaic energy storage charging station described in this application embodiment, those skilled in the art can understand the specific implementation method and various variations of the electronic device in this embodiment based on the integrated charging and discharging management system and method based on a photovoltaic energy storage charging station described in this application embodiment. Therefore, how the electronic device implements the method in this application embodiment will not be described in detail here. As long as those skilled in the art implement the integrated charging and discharging management system and method based on a photovoltaic energy storage charging station described in this application embodiment, the electronic device used is within the scope of protection of this application.

[0064] It should be noted that all formulas in this manual are calculated by removing dimensions and taking their numerical values. The formulas are derived from software simulations based on a large amount of collected data to obtain the most recent real-world results. The preset parameters and thresholds in the formulas are set by those skilled in the art according to the actual situation.

[0065] The above description is merely a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for users of ordinary technical skills, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A charging and discharging integrated management system based on a photovoltaic energy storage charging station, characterized in that, include: The voltage reference module is used to acquire the DC bus voltage, match the DC bus voltage with a preset voltage range, determine the converter response direction, and generate the default response power of each converter as the reference power. The capacity reconfiguration module is used to obtain the equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristics of the energy storage battery cluster, determine the battery cluster degradation state, and correct the preset upper and lower boundaries of the state of charge and the upper limit of the charge and discharge rate to obtain the dynamic available capacity boundary and power upper limit of the battery cluster. The power generation module is used to generate power scheduling instructions for charging and discharging photovoltaic and energy storage battery clusters, based on the dynamic available capacity boundary and power upper limit constraints of the battery cluster and the reference power. The capacity reservation module is used to divide the emergency backup capacity, power grid response capacity and free dispatch capacity within the dynamic available capacity boundary, and to determine the free dispatch capacity as the callable capacity; The application scheduling module is used to allocate charging and discharging power to each charging pile in the charging station according to the power scheduling instructions, within the range of available capacity.

2. The integrated charging and discharging management system based on a photovoltaic energy storage charging station according to claim 1, characterized in that, Determining the converter response direction includes: The DC bus voltage is compared with a first voltage threshold and a second voltage threshold in a preset voltage range, and the converter response direction is determined based on the position of the DC bus voltage relative to the first voltage threshold and the second voltage threshold. When the DC bus voltage is less than the first voltage threshold in the preset voltage range, the converter is determined to execute the first response direction. When the DC bus voltage is greater than the second voltage threshold in the preset voltage range, the converter is determined to execute the second response direction. When the DC bus voltage is between the first voltage threshold and the second voltage threshold, the current response direction of the converter is maintained.

3. The integrated charging and discharging management system based on a photovoltaic energy storage charging station according to claim 2, characterized in that, The reference power includes: The corresponding power response range is determined based on the preset voltage range where the DC bus voltage is located, and the default response power of the converter is determined according to the position of the DC bus voltage in the corresponding power response range. The default response power of each converter is associated according to the converter type and response direction to form a reference power.

4. The integrated charging and discharging management system based on a photovoltaic energy storage charging station according to claim 3, characterized in that, Determining the battery cluster attenuation state includes: The actual cumulative equivalent cycle count, internal resistance change ratio relative to the initial internal resistance, and open-circuit voltage recovery characteristics corresponding to the most recent resting relaxation process of the energy storage battery cluster are obtained according to a preset period. The equivalent cycle count, internal resistance change ratio, and open-circuit voltage recovery characteristics are compared with the corresponding attenuation judgment conditions, and the attenuation state of the battery cluster is determined based on the comparison results.

5. The integrated charging and discharging management system based on a photovoltaic energy storage charging station according to claim 4, characterized in that, The preset state of charge upper and lower boundaries include the preset state of charge upper boundary and the preset state of charge lower boundary corresponding to when the battery cluster has not decayed; the upper limit of the charge / discharge rate is the upper limit of the rated charge / discharge rate. Based on the battery cluster's degradation state, the upper and lower boundaries of the preset state of charge and the lower boundary of the preset state of charge are corrected in opposite directions, and the upper limit of the rated charge-discharge rate is reduced according to the internal resistance change ratio, so that the corrected upper and lower boundaries of the state of charge and the upper limit of the charge-discharge rate correspond to the current degradation state of the battery cluster.

6. The integrated charging and discharging management system based on a photovoltaic energy storage charging station according to claim 5, characterized in that, The obtained dynamic available capacity boundary and power upper limit of the battery cluster include: The corrected upper boundary of the state of charge and the lower boundary of the state of charge are determined as the dynamic available capacity boundary corresponding to the current operating cycle of the battery cluster. The corrected upper limit of the charge / discharge rate is matched with the rated capacity of the battery cluster to obtain the upper limit of the power corresponding to the current operating cycle. The dynamic available capacity boundary and the upper limit of the power are updated based on the subsequently obtained equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristic change.

7. The integrated charging and discharging management system based on a photovoltaic energy storage charging station according to claim 6, characterized in that, The power scheduling instructions for generating and discharging photovoltaic and energy storage battery clusters include: The direction of photovoltaic power adjustment and the direction of charging or discharging of energy storage battery clusters are determined based on the reference power. The charging and discharging power of energy storage battery clusters is determined according to the power difference between photovoltaic output power and charging station power demand, so that the charging and discharging power of energy storage battery clusters does not exceed the power upper limit and the state of charge of energy storage battery clusters is within the dynamic available capacity boundary, and corresponding power dispatch instructions are generated.

8. The integrated charging and discharging management system based on a photovoltaic energy storage charging station according to claim 7, characterized in that, The step of determining the freely schedulable capacity as the callable capacity includes: Based on the total capacity corresponding to the dynamic available capacity boundary, the emergency backup capacity, grid response capacity, and free dispatch capacity are divided in sequence. The remaining capacity after the emergency backup capacity and grid response capacity are reserved is determined as the free dispatch capacity, and the free dispatch capacity is used as the callable capacity when the energy storage battery cluster participates in the power regulation of the charging pile.

9. The integrated charging and discharging management system based on a photovoltaic energy storage charging station according to claim 8, characterized in that, The allocation of charging and discharging power to each charging pile within the charging station includes: Obtain the charging and discharging power demand corresponding to each charging pile, determine the power allocation relationship corresponding to each charging pile according to the power scheduling instruction, determine the allocated charging and discharging power based on the charging and discharging power demand corresponding to each charging pile, so that the sum of the power call amount of the energy storage battery cluster corresponding to each charging pile does not exceed the callable capacity, and the allocated charging and discharging power of each charging pile does not exceed the power corresponding to the power scheduling instruction.

10. A charging and discharging integrated management method based on a photovoltaic energy storage charging station, implemented by any one of claims 1 to 9, characterized in that, include: S1. Acquire the DC bus voltage, match the DC bus voltage with the preset voltage range, determine the converter response direction, and generate the default response power of each converter as the reference power; S2. Obtain the equivalent cycle number, internal resistance change ratio and open circuit voltage recovery characteristics of the energy storage battery cluster, determine the battery cluster decay state, and correct the preset upper and lower boundaries of the state of charge and the upper limit of the charge and discharge rate to obtain the dynamic available capacity boundary and power upper limit of the battery cluster. S3. Under the constraints of the dynamic available capacity boundary and power upper limit of the battery cluster, and in combination with the reference power, generate power dispatch instructions for charging and discharging of photovoltaic and energy storage battery clusters. S4. Divide the emergency backup capacity, power grid response capacity and free dispatch capacity within the dynamic available capacity boundary, and determine the free dispatch capacity as the callable capacity; S5. According to the power scheduling instruction, allocate charging and discharging power to each charging pile in the charging station within the range of available capacity.

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