Compensation control method and system for direct-current coupling photovoltaic distribution and storage system

Abstract

The invention provides a compensation control method and system for a direct-current coupling photovoltaic distribution and storage system, electronic equipment and a storage medium, and the method achieves the precise compensation of photovoltaic output through the closed-loop logic of illumination data association, energy storage configuration calculation and real-time compensation control: firstly, obtaining the actual measurement and theoretical illumination radiation data of a project location; calculating a compensation parameter representing the photovoltaic power compensation proportion based on the deviation between the two, and determining the average output power and the configuration capacity of the energy storage unit according to the parameter; a real-time compensation coefficient is calculated according to the ratio of real-time measured data to theoretical illumination radiation data, system target output power is determined according to the real-time compensation coefficient and photovoltaic power generation power, and then expected energy storage output power is calculated according to the difference value of the target output power and the photovoltaic power generation power and a dynamic correction factor. And generating a current instruction according to the expected energy storage output power and the reference voltage of the shared DC bus, and controlling energy storage charging and discharging through a bidirectional DC / DC converter, so that the actual output power reaches a target value.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic power generation and energy storage coordinated control technology, and in particular to a compensation control method and system for DC-coupled photovoltaic power generation and energy storage systems. Background Technology

[0002] Photovoltaic power generation systems, based on the photovoltaic effect in semiconductors, have become one of the core renewable energy technologies for addressing global energy transition and carbon neutrality goals. Among these, DC-coupled photovoltaic (PV) power storage systems have become the mainstream direction for retrofitting existing PV projects due to their ability to reduce losses in AC / DC conversion and improve energy utilization efficiency. Key technologies and parameters involved in this type of system include Maximum Power Point Tracking (MPPT), Energy Management System (EMS), Power Conversion System (PCS), State of Charge (SOC), and State of Health (SOH), which are crucial for ensuring system operation.

[0003] Existing photovoltaic (PV) inverters control the operating voltage of PV equipment using the MPPT method to obtain maximum power, while energy storage devices charge and discharge according to the EMS-specified strategy combined with their own SOC (State of Charge) status. However, there is a lack of mutually coupled guidance strategies between the two. PV power generation is limited by the duration of sunlight and is easily affected by weather. As the proportion of PV power generation in the grid increases, the pressure on grid dispatching increases, leading to strict deviation assessments and curtailment requirements for PV power plants, significantly impacting power generation revenue. Simultaneously, the power generation of PV power plants declines year by year, causing a continuous decrease in power generation within the grid's permitted operating time, which is detrimental to the long-term operation of projects. Furthermore, existing renewable energy distribution and storage systems often employ a collaborative approach between newly built energy storage power plants and existing PV power plants. This inevitably increases the costs of grid connection, registration, and retrofitting, and the grid needs to reassess the new equipment to mitigate stability risks.

[0004] In existing technologies, some related solutions only focus on the control methods of photovoltaic MPPT or use approximate power generation algorithms for energy storage configuration, failing to achieve deep coupling control between photovoltaics and energy storage, and also failing to form a precise calculation and energy storage capacity optimization configuration scheme for the expected annual power generation curve of photovoltaics. This leads to unreasonable energy storage capacity configuration, low equipment utilization, and difficulty in effectively avoiding power curtailment problems while retaining the original project's registered capacity and grid-connected equipment, failing to balance the economic benefits of retrofitting with the need to improve power generation revenue. Summary of the Invention

[0005] This invention provides a compensation control method, system, electronic device, and storage medium for DC-coupled photovoltaic energy storage systems, in order to solve the technical problems in the current technology, such as the lack of coupling guidance strategies between photovoltaics and energy storage, low returns of photovoltaic power generation due to weather and attenuation, high grid dispatch pressure, high cost of new energy storage and energy storage transformation and the need for re-registration, and the failure of existing solutions to achieve accurate energy storage configuration and photovoltaic output compensation.

[0006] In a first aspect, embodiments of the present invention provide a compensation control method for a DC-coupled photovoltaic (PV) power generation and energy storage system. The PV power generation system includes a PV power generation unit, an energy storage unit, and a DC / AC inverter connected via a shared DC bus. The PV power generation unit includes a PV array and a maximum power point tracking (MPPT) DC / DC converter. The energy storage unit includes an energy storage battery and a bidirectional DC / DC converter. The compensation control method includes: S1. Obtain measured solar radiation data and theoretical solar radiation data of the location of the photovoltaic project; S2. Based on the deviation between the measured solar radiation data and the theoretical solar radiation data, calculate the compensation parameters used to characterize the photovoltaic power generation compensation ratio; S3. Based on the compensation parameters, determine the average output power and configuration capacity of the energy storage unit; S4. During the operation of the DC-coupled photovoltaic power generation and storage system, calculate the real-time compensation coefficient based on the ratio of real-time measured solar radiation data to real-time theoretical solar radiation data. S5. Determine the target output power of the DC-coupled photovoltaic power generation system based on the real-time compensation coefficient and the photovoltaic power generation power. S6. Based on the difference between the target output power and the photovoltaic power generation, and combined with the dynamic correction factor, calculate the expected energy storage output power; S7. Based on the desired energy storage output power and the shared DC bus reference voltage, generate an output current command for the energy storage battery, and control the charging and discharging of the energy storage battery through the bidirectional DC / DC converter, so that the actual output power of the DC-coupled photovoltaic power distribution and storage system reaches the target output power.

[0007] Preferably, in step S1, the measured solar radiation data includes hourly solar radiation information for the project location over a year. The solar radiation information includes declination angle, hour angle, solar altitude angle, and solar incidence angle. The hour angle is calculated based on the longitude of the project location and the corresponding time zone. The solar altitude angle is calculated based on the latitude of the project location. The solar incidence angle is calculated based on the tilt angle, azimuth angle, and solar azimuth angle of the photovoltaic module.

[0008] Preferably, S2 specifically includes: Using the hourly data of several locations at the photovoltaic project site throughout the year as the calculation period, the difference between the theoretical hourly solar radiation data and the actual hourly solar radiation data for the corresponding time period is calculated. The difference is divided by the actual hourly solar radiation data to obtain the gain ratio that the photovoltaic power generation needs to be supplemented in the hourly dimension. The gain ratio is defined as the compensation parameter.

[0009] Preferably, S3 specifically includes: S31. Filter the hourly compensation parameters obtained in S2 and retain only the compensation parameters with positive values. S32. Calculate the arithmetic mean of all positive compensation parameters after screening, and multiply the average value by the preset rated operating power of the photovoltaic project to obtain the average output power that the energy storage unit needs to provide. S33. Multiply the average output power of the energy storage unit by the preset rated operating time of the photovoltaic project during the grid-allowed grid connection period to obtain the configured capacity of the energy storage unit.

[0010] Preferably, in step S5, the dynamic correction factor includes at least one of the following: inverter efficiency correction factor, battery state of charge (SOC) correction factor, temperature correction factor, battery health (SOH) correction factor, and fuzzy control correction factor. The inverter efficiency correction factor is determined based on the inverter's AC / DC conversion efficiency, and the inverter efficiency correction factor is the reciprocal of the inverter's conversion efficiency. The SOC correction factor adopts nonlinear quadratic curve control: a maximum SOC threshold and a minimum SOC threshold are set. When the SOC is less than or equal to the minimum SOC threshold, the SOC correction factor is 0 to limit battery discharge; when the SOC is greater than or equal to the maximum SOC threshold, the SOC correction factor is 1 to allow the battery to output full power; when the SOC is between the maximum SOC threshold and the minimum SOC threshold, the SOC correction factor is calculated based on the difference between the SOC and the maximum and minimum SOC thresholds. The temperature correction factor is based on 25°C: within the specified operating temperature range of the energy storage unit, for every 10°C deviation from the reference temperature, the battery efficiency decreases by 5%, and the temperature correction factor is calculated based on the difference between the actual operating temperature and the reference temperature. The SOH correction factor is linearly controlled within the set upper and lower limits of SOH; when SOH is lower than the set lower limit of SOH, the SOH correction factor limits the energy storage unit to output only 50% of its power. The control logic of the fuzzy control correction factor is as follows: based on the actual operating data of the energy storage unit and the preset system boundary conditions, the rule weights are set to dynamically adjust the expected energy storage output power.

[0011] Preferably, in step S7, generating the output current command for the energy storage battery specifically includes: The output current value of the energy storage battery is calculated by dividing the desired energy storage output power by the shared DC bus reference voltage. Based on the output current value, the bidirectional DC / DC converter adopts a dual-loop control strategy of current inner loop and voltage outer loop to control the charging and discharging current of the battery, and controls and maintains the voltage of the shared DC bus at the reference voltage, so that the actual output power of the DC-coupled photovoltaic power generation and storage system reaches the target output power.

[0012] As a preferred option, energy storage charging control is also included: When the photovoltaic power generation is greater than the target output power, the corresponding energy storage charging strategy is executed according to the type of converter equipment in the DC-coupled photovoltaic power distribution and storage system. If the converter is a unidirectional photovoltaic inverter, the overflow power during the photovoltaic power curtailment period is used to charge the energy storage battery. If the converter is a bidirectional energy storage converter, it utilizes the overflow power during photovoltaic power curtailment and the off-peak electricity price period at night for charging, and sets the target output power to the maximum allowable input power of the energy storage converter during the off-peak electricity price period at night.

[0013] Secondly, embodiments of the present invention provide a compensation control system for a DC-coupled photovoltaic power generation and energy storage system. The DC-coupled photovoltaic power generation and energy storage system includes a photovoltaic power generation unit, an energy storage unit, and a DC / AC inverter connected via a shared DC bus. The photovoltaic power generation unit includes a photovoltaic array and a maximum power point tracking (MPPT) DC / DC converter. The energy storage unit includes an energy storage battery and a bidirectional DC / DC converter. The compensation control system includes: The data acquisition and processing module is used to acquire measured solar radiation data and theoretical solar radiation data of the photovoltaic project site; The compensation parameter calculation module is used to calculate the compensation parameters that characterize the photovoltaic power generation compensation ratio based on the deviation between the measured solar radiation data and the theoretical solar radiation data. The capacity configuration module is used to determine the average output power and configured capacity of the energy storage unit based on the compensation parameters. The real-time compensation coefficient calculation module is used to calculate the real-time compensation coefficient based on the ratio of real-time measured solar radiation data to real-time theoretical solar radiation data during the operation of the DC-coupled photovoltaic power generation and storage system. The target power determination module is used to determine the target output power of the DC-coupled photovoltaic power generation system based on the real-time compensation coefficient and the photovoltaic power generation. The energy storage power calculation module is used to calculate the expected energy storage output power based on the difference between the target output power and the photovoltaic power generation power, combined with a dynamic correction factor. The charge / discharge control module is used to generate an output current command for the energy storage battery based on the desired energy storage output power and the shared DC bus reference voltage, and to control the charging and discharging of the energy storage battery through the bidirectional DC / DC converter, so that the actual output power of the DC-coupled photovoltaic power distribution and storage system reaches the target output power.

[0014] Thirdly, embodiments of the present invention provide 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 program, it implements the steps of the compensation control method for a DC-coupled photovoltaic power generation and storage system as described in the first aspect of the present invention.

[0015] Fourthly, embodiments of the present invention provide a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the compensation control method for a DC-coupled photovoltaic power distribution and storage system as described in the first aspect of the present invention.

[0016] This invention provides a compensation control method, system, electronic device, and storage medium for a DC-coupled photovoltaic (PV) power generation and energy storage system (including PV power generation units, energy storage units, and DC / AC inverters connected to a shared DC bus). The core technical idea of ​​this system is to achieve precise PV output compensation through a closed-loop logic of "illuminance data association - energy storage configuration calculation - real-time compensation control": First, measured and theoretical illuminance data of the project site are acquired. Based on the deviation between the two, a compensation parameter characterizing the PV power compensation ratio is calculated. Then, the average output power and configuration capacity of the energy storage unit are determined based on this parameter. During system operation, a real-time compensation coefficient is calculated by combining the ratio of real-time measured and theoretical illuminance data. This coefficient, along with the PV power measured by the MPPT DC / DC converter, determines the system's target output power. Subsequently, based on the difference between the target output power and the PV power, and combined with a dynamic correction factor, the desired energy storage output power is calculated. Finally, a current command is generated based on the desired energy storage output power and the shared DC bus reference voltage. The charging and discharging of the energy storage is controlled through a bidirectional DC / DC converter, enabling the system's actual output power to reach the target value. This solution can accurately match energy storage capacity, avoid over-sizing and waste, and improve energy storage utilization. It does not require modification of the original photovoltaic grid-connected equipment and project filing information, reducing the cost of modification and grid assessment. It can avoid the impact of photovoltaic output fluctuations caused by weather and component degradation and grid curtailment, thereby improving the revenue of photovoltaic power generation. At the same time, it makes the system output stable and predictable, which is convenient for grid dispatch and power station participation in electricity market transactions. Furthermore, the dynamic correction factor can ensure the safe operation of energy storage batteries and extend their service life. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a compensation control method for a DC-coupled photovoltaic power generation and storage system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a DC-coupled photovoltaic energy storage system according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the compensation control of a DC-coupled photovoltaic power generation and storage system according to an embodiment of the present invention; Figure 4 This is a block diagram of the compensation control system for a DC-coupled photovoltaic power generation and storage system; Figure 5 This is a schematic diagram of the physical structure according to an embodiment of the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0020] In the embodiments of this application, the term "and / or" is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0021] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0022] This invention provides a compensation control method for a DC-coupled photovoltaic (PV) power generation and energy storage system. The PV power generation system includes a PV power generation unit, an energy storage unit, and a DC / AC inverter connected via a shared DC bus. The PV power generation unit includes a PV array and a maximum power point tracking (MPPT) DC / DC converter. The energy storage unit includes an energy storage battery and a bidirectional DC / DC converter. Figure 1 , Figure 2 As shown, the compensation control method includes: S1. Obtain measured solar radiation data and theoretical solar radiation data of the location of the photovoltaic project.

[0023] Among them, measured solar radiation data refers to quantitative data reflecting the actual solar radiation conditions at the project site, obtained from meteorological stations or the Meteonorm database deployed at the photovoltaic project site. In this embodiment, it is hourly solar radiation information from 8760 points throughout the year, which can directly reflect the true solar radiation intensity under weather conditions such as cloudy, partly cloudy, and dusty weather. For example, the measured radiation in a certain area during a cloudy afternoon in summer may only be 60% of that on a sunny day. Theoretical solar radiation data refers to data based on the latitude and longitude of the project site, time, combined with the declination angle (latitude of the subsolar point, which varies with the number of days in a year) and the hour angle (reflecting the relative noon of the sun). The ideal light intensity data, derived from parameters such as offset angle (calculated based on local longitude and corresponding time zone), solar altitude angle (reflecting the sun's altitude relative to the horizon, calculated based on local latitude), and incident angle of sunlight (reflecting the angle at which sunlight irradiates the photovoltaic module, calculated based on the module tilt angle, azimuth angle, and solar azimuth angle), represents the light level under ideal climatic conditions with no weather interference, no module shading, and no dust cover. For example, the theoretical radiation at noon on the summer solstice in a certain location can be calculated by combining the solar vertical radiation flux of 1360W / m² with the incident angle of sunlight. The photovoltaic power generation unit includes a photovoltaic array and an MPPT DC / DC converter, which is responsible for converting light energy into electrical energy and tracking maximum power output. The energy storage unit includes an energy storage battery and a bidirectional DC / DC converter, which is responsible for storing and releasing electrical energy. The shared DC bus includes a common DC voltage circuit connecting the photovoltaic, energy storage, and DC / AC inverters to ensure voltage matching of multiple devices. The DC / AC inverter is used to invert DC power into AC power for grid connection or for load use.

[0024] In this embodiment, S1 is the basic data acquisition stage of the entire compensation algorithm. First, measured data is obtained through database and on-site calculations, and then theoretical data is derived through astronomical and geographical parameters. The core defect of the existing technology is that it has not established a correlation system between "measured-theoretical" illumination data, which leads to a lack of accurate data support for subsequent energy storage configuration and compensation control. Either the energy storage configuration is blind due to relying solely on measured data, or the compensation is detached from reality due to relying solely on theoretical data. By acquiring two types of data simultaneously, S1 solves the problem of lack of data support in the existing technology, providing a reliable data foundation for subsequent calculation of compensation parameters and determination of energy storage capacity. This ensures that the subsequent algorithm stages do not deviate from the actual illumination conditions of the project and avoids unfounded over-allocation or under-allocation of energy storage.

[0025] S2. Based on the deviation between the measured solar radiation data and the theoretical solar radiation data, calculate the compensation parameters used to characterize the photovoltaic power generation compensation ratio.

[0026] The compensation parameter is the percentage increase required to boost the hourly photovoltaic (PV) power output. The calculation logic is (theoretical solar radiation data - measured solar radiation data) / measured solar radiation data. This quantifies the PV power shortfall caused by weather factors. For example, if the theoretical solar radiation is 1000 W / m² and the measured radiation is 800 W / m², the compensation parameter is 0.25, meaning the PV power output needs a 25% increase to reach the ideal level. The PV power compensation ratio refers to the proportion of PV power that the energy storage unit needs to supplement relative to the current actual PV output power. This is the core physical meaning of the compensation parameter and directly guides the energy storage discharge intensity. For example, if the compensation ratio is 0.3, and the current PV output is 500 kW, the energy storage needs to supplement 150 kW.

[0027] In this embodiment, the two types of illumination data acquired in S1 are used as input. The "illumination difference" is transformed into "power compensation demand" through deviation calculation, establishing a quantitative correlation between illumination data and power compensation. The core defect of the existing technology is that it can only qualitatively determine the decline in photovoltaic power due to weather, and cannot quantitatively calculate the proportion of power that needs to be compensated, resulting in either excessive (wasting energy) or insufficient (failing to meet the ideal output) energy storage discharge. This step solves the problem of the inability to quantify the power compensation demand in the existing technology by accurately calculating the compensation parameters, clarifying the specific shortfall ratio of photovoltaic power per hour, and providing a quantitative basis for the subsequent calculation of the average output power of the energy storage unit and real-time compensation control, ensuring that energy storage compensation is supplied on demand and avoiding blind operation.

[0028] S3. Based on the compensation parameters, determine the average output power and configuration capacity of the energy storage unit.

[0029] The average output power of the energy storage unit refers to the average power output level of the energy storage unit during the compensation period. The calculation logic is "arithmetic mean of all positive compensation parameters × rated operating power of the photovoltaic project," representing the average compensation capacity that the energy storage needs to maintain over a long period. For example, if the average positive compensation parameter is 0.2 and the rated operating power of the photovoltaic project is 1MW, the average output power of the energy storage unit is 200kW. The configured capacity of the energy storage unit refers to the total capacity of the energy storage batteries required to meet the compensation needs. The calculation logic is "average output power of the energy storage unit × rated operating time of the photovoltaic project." This directly guides the selection of energy storage equipment. For example, when the average output power is 200kW and the rated operating time is 8 hours (average daily effective power generation time), the energy storage configuration capacity is 1600kWh. The rated operating power is the design output power of the photovoltaic project under the grid-allowed grid connection conditions. For example, the rated operating power of a photovoltaic project with a registered capacity of 1MW is usually set at 1MW. The rated operating time is the preset stable power generation time of the photovoltaic project during the grid-allowed grid connection period. For example, if the local grid allows photovoltaic grid connection from 9:00 to 17:00, the rated operating time is 8 hours.

[0030] In this embodiment, the core configuration parameters of energy storage are first determined. The core defect of the existing technology is that the energy storage capacity configuration relies on experience estimation (such as configuring it according to 20% of the photovoltaic installed capacity), which is prone to over-configuration (increasing investment costs) or under-configuration (failing to meet compensation requirements), and the need for re-registration leads to complicated transformation. This step accurately calculates the configuration capacity through compensation parameters, which solves the problems of unreasonable energy storage capacity configuration and high transformation costs in the existing technology, achieves accurate matching of energy storage capacity, avoids over-configuration waste and investment redundancy, and since the configuration logic is based on the rated parameters of the original project, there is no need to adjust the project registration information, reducing the additional evaluation steps of the power grid for the new equipment and reducing the complexity of transformation.

[0031] S4. During the operation of the DC-coupled photovoltaic power generation and storage system, calculate the real-time compensation coefficient based on the ratio of the real-time measured solar radiation data to the real-time theoretical solar radiation data.

[0032] Among them, the real-time compensation coefficient refers to the proportional coefficient calculated in real time during system operation to compensate the actual photovoltaic power to the ideal level. The calculation logic is "real-time theoretical solar radiation data / real-time measured solar radiation data". It can dynamically respond to solar radiation fluctuations. For example, if a cloud suddenly appears at a certain moment and the real-time measured radiation drops to 70% of the ideal value, the real-time compensation coefficient is about 1.43, and energy storage is needed to supplement 43% of the power. The real-time measured solar radiation data is the current solar radiation collected in real time by the on-site weather station during system operation. It is updated once a minute to reflect instantaneous changes in solar radiation, such as the real-time radiation drop when clouds suddenly appear on a sunny day. The real-time theoretical solar radiation data is the ideal solar radiation derived in real time based on the current time and latitude and longitude during system operation. It serves as the ideal benchmark for instantaneous compensation in application scenarios. For example, the theoretical radiation at the current moment (12:00) can be calculated in real time as 1200W / m².

[0033] In this embodiment, two types of illumination data are collected in real time during system operation, and coefficients are calculated to replace the static compensation parameters in S2, thereby achieving dynamic compensation. The core defect of the existing technology is that it adopts a static compensation strategy (such as a fixed compensation ratio throughout the day), which cannot cope with instantaneous fluctuations in illumination (such as short-term showers or cloud cover), resulting in compensation lag or deviation. This step solves the problem of the lack of real-time compensation and inability to cope with dynamic changes in illumination in the existing technology by calculating the compensation coefficient in real time. This allows the compensation strategy to match the instantaneous illumination conditions in real time. At the same time, since the coefficient is calculated based on the illumination ratio, it can naturally eliminate the interference of external factors such as photovoltaic array shadows, component dust, and annual degradation on the system's energy efficiency ratio (such as the decrease in measured radiation caused by component dust accumulation, the coefficient can be adjusted synchronously to ensure accurate compensation), thus improving the stability of compensation.

[0034] S5. Determine the target output power of the DC-coupled photovoltaic power generation system based on the real-time compensation coefficient and the photovoltaic power generation.

[0035] The target output power refers to the ideal output power that the system needs to achieve. The calculation logic is "real-time compensation coefficient × photovoltaic power generation". This sets a clear target for energy storage compensation. For example, if the photovoltaic output is currently 800kW through the MPPT DC / DC converter and the real-time compensation coefficient is 1.25, then the target output power is 1000kW. The photovoltaic power generation refers to the actual output power of the photovoltaic system collected in real time by the MPPT DC / DC converter during system operation. In the application scenario, it reflects the maximum power output capability of the photovoltaic system. For example, if the current photovoltaic power tracked by MPPT is 800kW, it represents the maximum power generation level of the photovoltaic system under the current irradiance.

[0036] In this embodiment, the real-time compensation coefficient (ideal ratio) and the actual photovoltaic power (current baseline) are used as inputs to determine the final output target that the system needs to achieve, connecting the compensation demand with the execution target. The core defect of the existing technology is that it does not clearly define the ideal output target of the system, and only relies on the random superposition output of photovoltaic + energy storage, resulting in large fluctuations in output power, making it difficult to meet the grid's requirements for grid-connected power stability and easily facing deviation assessments. This step solves the problem of existing technology systems having no clear output target and large grid-connected power fluctuations by calculating the target output power. It sets a clear and quantifiable execution benchmark for energy storage compensation, ensuring that the system output always conforms to the power curve under ideal weather conditions (such as the ideal output curve on a sunny day), reducing grid-connected power fluctuations, reducing the risk of grid deviation assessments, and providing a clear direction for subsequent energy storage power calculations.

[0037] S6. Based on the difference between the target output power and the photovoltaic power generation, and combined with the dynamic correction factor, calculate the expected energy storage output power.

[0038] Among them, the expected energy storage output power refers to the actual power that the energy storage unit needs to output. The calculation logic is "(target output power - photovoltaic power generation) × dynamic correction factor", which directly guides the energy storage discharge intensity. The dynamic correction factor ensures that the energy storage output matches the equipment status and external conditions.

[0039] In this embodiment, the difference between the photovoltaic power and the target power (the theoretical power to be compensated) is first calculated, and then adjusted to the actual executable power of the energy storage through a dynamic correction factor. The core defect of the prior art is that it directly controls the energy storage output according to the power difference without considering factors such as inverter losses and battery status (such as low SOC, high temperature), which leads to the energy storage output exceeding the equipment's capacity (such as over-discharge damaging the battery at low SOC) or the compensation power failing to reach the target due to losses. This step solves the problems of the prior art not taking into account the equipment status and external losses, easily damaging the equipment, or inaccurate compensation by introducing a dynamic correction factor. It ensures that the energy storage output is within the equipment's safe range (protecting battery life and avoiding inverter overload), while correcting the impact of external losses, so that the actual compensation power accurately matches the demand and improves the reliability of compensation.

[0040] S7. Based on the desired energy storage output power and the shared DC bus reference voltage, generate an output current command for the energy storage battery, and control the charging and discharging of the energy storage battery through the bidirectional DC / DC converter, so that the actual output power of the DC-coupled photovoltaic power distribution and storage system reaches the target output power.

[0041] Among them, the shared DC bus reference voltage refers to the reference voltage set to unify the output voltage of photovoltaic and energy storage, ensuring that the DC output voltage of photovoltaic (after MPPT DC / DC conversion) and energy storage (after bidirectional DC / DC conversion) is consistent, and avoiding power loss caused by bus voltage fluctuations; the output current command refers to the energy storage current control signal calculated based on the expected energy storage output power and the reference voltage. The calculation logic is "expected energy storage output power / shared DC bus reference voltage", which guides the current output of the bidirectional DC / DC converter; the bidirectional DC / DC converter (a converter device that can realize bidirectional control of energy storage battery charging and discharging, converts the battery DC voltage to the bus voltage to output power during discharging, and converts the bus DC voltage to the battery voltage to store electrical energy during charging, and is the core component for energy storage power execution); the actual output power (refers to the final power of the system connected to the grid or supplied to the load through the DC / AC inverter, which must be consistent with the target output power).

[0042] In this embodiment, the desired energy storage power is converted into a current command, and charge / discharge control is executed through a bidirectional DC / DC converter to ultimately achieve the target system output, forming a compensation control closed loop. The core defect of the prior art is that there is no unified voltage reference on the DC side, resulting in a mismatch between the output voltage of photovoltaic and energy storage, leading to large power losses. Furthermore, the lack of a precise current control strategy makes it impossible to ensure that the actual output meets the target. At the same time, bidirectional charge / discharge control is not considered (e.g., the overflow power cannot be used for charging during power curtailment). This step solves the problems of inconsistent DC side voltage, large power losses, and inability to close the control loop in the prior art by unifying the bus voltage and precise current control. It maintains the stability of the shared DC bus voltage, reduces losses in the AC / DC conversion link, and ensures that the actual system output accurately reaches the target power. At the same time, the bidirectional DC / DC converter supports charging control, laying the foundation for subsequent charging using overflow power from power curtailment or off-peak electricity prices, further improving energy utilization and project returns.

[0043] Based on the above embodiments, as a preferred implementation, in step S1, the measured solar radiation data includes hourly solar radiation information of the project location for one year. The solar radiation information includes declination angle, hour angle, solar altitude angle, and solar incidence angle. The hour angle is calculated based on the longitude of the project location and the corresponding time zone. The solar altitude angle is calculated based on the latitude of the project location. The solar incidence angle is calculated based on the tilt angle, azimuth angle, and solar azimuth angle of the photovoltaic module.

[0044] Specifically, the declination angle δ (latitude of the subsolar point) is approximated by the following formula based on the number of days in a year, n (n=1 for January 1st):

[0045] The hour angle h reflects the angle of the sun's offset from noon and can be calculated using the local longitude and the corresponding time zone.

[0046] The solar altitude angle α reflects the sun's altitude relative to the horizon and can be expressed using latitude. Calculation yielded:

[0047] The incident angle θ reflects the intensity of sunlight reflected onto the photovoltaic module panel, and can be calculated using the tilt angle β of the photovoltaic module, the azimuth angle γp, and the azimuth angle γ of the sun.

[0048] Among them, the solar azimuth angle

[0049] Local theoretical irradiance information can be calculated (data from 8760 points): Etheoretical irradiance = S0 (solar vertical radiation flux 1360 W / m2). cosθ.

[0050] Based on the above embodiments, as a preferred implementation, step S2 specifically includes: Using the hourly data of several locations at the photovoltaic project site throughout the year as the calculation period, the difference between the theoretical hourly solar radiation data and the actual hourly solar radiation data for the corresponding time period is calculated. The difference is divided by the actual hourly solar radiation data to obtain the gain ratio that the photovoltaic power generation needs to be supplemented in the hourly dimension. The gain ratio is defined as the compensation parameter.

[0051] In this embodiment, the actual time dimension covering the project location is 8760 hours throughout the year (i.e., from 0:00 on January 1st to 23:00 on December 31st, with each hour as an independent calculation unit). This can comprehensively capture the light variation patterns of different seasons (e.g., strong light in summer, weak light in winter), different time periods (e.g., peak at noon, low in the morning and evening), and different weather conditions (e.g., sunny days, cloudy days, dusty days). This avoids the one-sidedness of compensation parameters caused by excessively short data periods (e.g., only collecting data for a few months) or coarse time granularity (e.g., calculated on a daily basis). The hourly theoretical solar radiation data refers to the latitude and longitude of the project location, the corresponding hourly declination angle (e.g., on July 1st, n=182, declination angle approximately 23.45°), hour angle (e.g., in the region of 116°E, the hour angle at 12:00 Beijing time is approximately 0°), solar altitude angle (calculated through local latitude), and incident angle of sunlight (summarized from the project location's latitude and longitude). The ideal irradiance (based on a solar vertical radiation flux of 1360 W / m²) derived from the calculation of the tilt angle and azimuth angle of the photovoltaic modules represents the ideal power generation irradiance conditions for that hour, with no weather interference and no shading / dust covering of the photovoltaic modules. The hourly measured irradiance data refers to the actual irradiance of the corresponding hour obtained through the meteorological station or meteorological database deployed at the project site, directly reflecting the actual impact of weather fluctuations, module dust accumulation, etc. The gain ratio that needs to be supplemented for photovoltaic power generation refers to the proportion of power that the energy storage unit needs to supplement to the current actual output power of the photovoltaic in order to achieve the power level of the photovoltaic under ideal climatic conditions. It is the key bridge for converting irradiance differences into power demand. The compensation parameter is the quantitative result of the above gain ratio, which is the core intermediate parameter connecting irradiance data and energy storage compensation control.

[0052] In this embodiment, the 8760 hours of the year are used as independent calculation units. First, the difference between "theoretical solar radiation data per hour - measured solar radiation data per hour" is calculated for each hour. Then, this difference is divided by the measured solar radiation data for the corresponding hour, and the resulting hourly gain ratio is defined as the compensation parameter. The core defect of existing technologies is that they can only qualitatively determine that weather conditions will cause a decrease in photovoltaic power, and cannot quantitatively calculate the specific compensation ratio for different hours and operating conditions. This results in either excessive (wasting energy) or insufficient (failing to meet ideal output requirements) energy storage discharge, and a lack of unified compensation parameters as a basis for subsequent energy storage configuration. This step... The aforementioned hourly and yearly quantitative calculations solve the technical problem of the inability to accurately quantify power compensation requirements in existing technologies. This provides reliable hourly and full-scenario data support for the accurate calculation of the average output power and configuration capacity of energy storage units in S3 and the dynamic derivation of real-time compensation coefficients in S4. It ensures that energy storage compensation is always "supplyed on demand" and avoids blind operation. At the same time, the distribution pattern of compensation parameters (such as the generally lower compensation parameters at noon in summer and the higher compensation parameters in the early morning in winter) can lay a data foundation for differentiated energy storage scheduling strategies for different seasons and time periods (such as prioritizing energy storage power for early morning compensation in winter) and further improve compensation efficiency.

[0053] Based on the above embodiments, as a preferred implementation, step S3 specifically includes: S31. The hourly compensation parameters obtained in S2 are filtered, and only compensation parameters with positive values ​​are retained.

[0054] Among them, the hourly compensation parameter refers to the parameter (Etheoretical irradiance - Eacterial irradiance) / Eacterial irradiance) calculated in S2 based on the hourly theoretical irradiance data and measured irradiance data of the project location, which can quantify the photovoltaic power gap in a single hour; the positive compensation parameter is the parameter with a value greater than 0 in the hourly compensation parameter. Only such parameters correspond to the time period when the actual photovoltaic output is lower than the ideal level (such as cloudy days, dusty days, and weak light periods in the morning and evening), which is an effective scenario for energy storage intervention.

[0055] In this embodiment, invalid time period data (time periods without energy storage compensation) with parameters ≤0 are removed from the 8760 hourly compensation parameters in S2, and only positive value data that needs compensation are retained. The defect of the prior art is that the compensation parameters are not screened, and negative or zero value parameters that do not need compensation are included in subsequent calculations, which leads to the distortion of energy storage configuration reference data and is prone to over-allocation of energy storage capacity. This step solves the problem of using invalid compensation data to calculate energy storage configuration in the prior art by screening positive compensation parameters, ensuring that the subsequent energy storage parameter calculation is based only on the actual time periods that need compensation, avoiding interference from invalid data, and laying the foundation for accurate calculation of the average output power of energy storage.

[0056] S32. Calculate the arithmetic mean of all positive compensation parameters after screening, and multiply the average value by the preset rated operating power of the photovoltaic project to obtain the average output power that the energy storage unit needs to provide.

[0057] Among them, the preset rated operating power of a photovoltaic project refers to the maximum design output power allowed by the grid when the photovoltaic project is registered. It is the benchmark output power of photovoltaics during the grid connection period, reflects the project's conventional power generation capacity, and is also an important reference parameter for grid dispatch. The average output power to be provided by the energy storage unit refers to the average power output level Delta that the energy storage needs to maintain over a long period during the compensation period. ave The calculation logic is the above arithmetic average × rated operating power (P). bat =Delta ave P pv ).

[0058] In this embodiment, the average gain ratio for the compensation period is first obtained using the arithmetic mean method, and then it is correlated with the rated operating power of the photovoltaic system to convert the ratio requirement into a specific power value. The defect of the prior art is that it directly estimates the average energy storage power according to a fixed ratio of the photovoltaic installed capacity without taking into account the actual compensation needs. This results in either insufficient energy storage power (unable to cover the average gap, resulting in poor compensation effect) or excessive energy storage power (equipment idle, increasing investment). This step solves the problem of blind estimation of the average output power of energy storage in the prior art by accurately calculating the average output power, so that the average energy storage power is accurately matched with the average gap of the photovoltaic system during the compensation period. This ensures the compensation effect and avoids investment waste and equipment redundancy caused by power over-match.

[0059] S33. Multiply the average output power of the energy storage unit by the preset rated operating time of the photovoltaic project during the grid-allowed grid connection period to obtain the configured capacity of the energy storage unit.

[0060] Among them, the grid-allowed grid connection period refers to the time period during which photovoltaic power generation can be grid-connected, as determined by the power grid based on regional load, voltage stability, and other requirements; the preset rated operating time refers to the duration during which photovoltaic projects can stably generate electricity when connected to the grid, determined based on the grid-allowed grid connection period, and is a benchmark time parameter set by combining grid dispatch rules and actual project operating experience; the energy storage unit configuration capacity refers to the total capacity of energy storage batteries required to meet compensation needs, calculated as the average output power of energy storage × rated operating time (C bat =P bat P bat ).

[0061] In this embodiment, the power demand is converted into capacity demand by combining the average output power of energy storage with the grid connection time allowed by the grid. The drawback of the existing technology is that the energy storage capacity configuration relies on experience (such as configuring according to the ratio of photovoltaic installed capacity of 1:0.2) and does not take into account the grid connection time limit, resulting in a mismatch between capacity and actual demand (such as configuring a large capacity for a short grid connection time, resulting in long-term battery idleness; or configuring a small capacity for a long grid connection time, which cannot meet the all-day compensation). Moreover, new energy storage requires re-registration and grid assessment, resulting in high transformation costs. This step calculates the capacity based on average power × rated operating time, which solves the problems of unreasonable energy storage capacity configuration and high transformation costs in the existing technology. It achieves accurate energy storage capacity configuration, reduces energy storage investment costs, and since the capacity calculation is based on the rated operating power and grid connection time of the original project (both of which are registered parameters), there is no need to adjust the project registration information, reducing the additional evaluation of new energy storage by the grid, shortening the transformation cycle, and reducing the complexity of transformation.

[0062] Based on the above embodiments, as a preferred implementation, in step S5, the dynamic correction factor includes at least one of the following: inverter efficiency correction factor, battery state of charge (SOC) correction factor, temperature correction factor, battery health (SOH) correction factor, and fuzzy control correction factor.

[0063] The inverter efficiency correction factor is determined based on the inverter's AC / DC conversion efficiency, and the inverter efficiency correction factor is the reciprocal of the inverter's conversion efficiency.

[0064] The SOC correction factor adopts nonlinear quadratic curve control: a maximum SOC threshold and a minimum SOC threshold are set. When the SOC is less than or equal to the minimum SOC threshold, the SOC correction factor is 0 to limit battery discharge; when the SOC is greater than or equal to the maximum SOC threshold, the SOC correction factor is 1 to allow the battery to output full power; when the SOC is between the maximum SOC threshold and the minimum SOC threshold, the SOC correction factor is calculated based on the difference between the SOC and the maximum and minimum SOC thresholds.

[0065] The temperature correction factor uses 25°C as the reference temperature: within the specified operating temperature range of the energy storage unit, for every 10°C deviation from the reference temperature, the battery efficiency decreases by 5%, and the temperature correction factor is calculated based on the difference between the actual operating temperature and the reference temperature.

[0066] The SOH correction factor is linearly controlled within the set upper and lower limits of SOH; when SOH is lower than the set lower limit of SOH, the SOH correction factor limits the energy storage unit to output only 50% of its power.

[0067] The control logic of the fuzzy control correction factor is as follows: based on the actual operating data of the energy storage unit and the preset system boundary conditions, the rule weights are set to dynamically adjust the expected energy storage output power.

[0068] Among them, the target output power P of the system is obtained. target Take the photovoltaic power generation P at the DC-DC converter. mppt Then the system target output power P target =P mppt f comp f comp This means that under the above system algorithm, the photovoltaic power generation needs to be compensated by energy storage to a specified value so that the photovoltaic power generation can reach the compensation coefficient of the ideal climate condition curve, which is often greater than 1. Real-time solar irradiance E is obtained from the project's weather station. real And calculate the theoretical solar radiation E based on the local latitude and longitude. targe Then the compensation coefficient f can be obtained. comp : f comp =E target / E real This invention calculates photovoltaic power gain by directly using the ratio of irradiance data. This eliminates fluctuations in the system performance ratio caused by external factors such as shading, dust, and degradation of the photovoltaic array during actual operation, resulting in more stable system compensation results.

[0069] Obtain the desired energy storage output power P bat :P bat =P target f-P mppt Here, f is a dynamic correction factor used to reflect the impact of battery status and external factors on system power.

[0070] f=f inverter f SOC f temp f SOH f fuzzy af inverter This represents the power loss caused by the AC / DC conversion of the inverter. If the inverter efficiency is n, then f inverter =1 / n.

[0071] bf SOC It is a dynamic correction factor based on battery SOC, using a non-linear quadratic curve. When the SOC is too low, battery discharge needs to be limited. The maximum and minimum SOC thresholds are set as follows: min and SOC max ,but: If SOC <= SOC min f SOC =0.

[0072] If SOC>= SOC max f SOC =1.

[0073] If SOC min <=SOC<=SOC max Using quadratic curve control: f SOC =(SOC - SOC min ) 2 / (SOC max - SOC min ) 2 .

[0074] cf temp It is a temperature-based dynamic correction factor. This coefficient is linearly controlled using a reference temperature, with T set... nominal =25, every 10 degrees Celsius change will cause the battery efficiency to decrease by 5%. Therefore, within the specified operating temperature range of the energy storage device: If T <= T nominal f temp =1-(T nominal -T) / 10 0.05.

[0075] If T>T nominal f _temp =1-(TT nominal ) / 10 0.05.

[0076] df SOH It is a dynamic correction factor based on battery health. The lower the State of Health (SOH), the lower the allowable discharge power; the higher the SOH, the higher the allowable discharge power. After setting the upper and lower limits of SOH, linear control is performed within the specified range. When the SOH falls below the set lower limit, the battery is only guaranteed to output 50% of its power to maintain battery life.

[0077] f SOH =(SOH max +SOH - 2SOH min ) / (2SOH max - 2SOH min ).

[0078] ef fuzzyIt is a control factor based on fuzzy control logic. Rule weights can be set based on other boundary conditions to dynamically control energy storage devices. In practical cases, the aforementioned dynamic factors often do not exhibit the predetermined linear or quadratic curve decay. Introducing fuzzy factors allows for dynamic control of the system at selected case sites based on actual energy storage operation data, ensuring system stability.

[0079] Based on the above embodiments, as a preferred implementation, in step S7, generating the output current command of the energy storage battery specifically includes: The output current value of the energy storage battery is calculated by dividing the desired energy storage output power by the shared DC bus reference voltage.

[0080] Among them, 3) Obtain the control current I of the energy storage DC converter bat The DC voltage V on the DC coupling bus of the energy storage photovoltaic system is set via the inverter. ref This unifies the voltage reference for photovoltaic output and energy storage output. Therefore: I bat =P bat / V ref Based on the output current value, the bidirectional DC / DC converter adopts a dual-loop control strategy of current inner loop and voltage outer loop to control the charging and discharging current of the battery, and controls and maintains the voltage of the shared DC bus at the reference voltage, so that the actual output power of the DC-coupled photovoltaic power generation and storage system reaches the target output power.

[0081] Current indicator I bat The output will be fed to the DC / DC converter, and the battery current will be controlled through the inner current loop and the outer voltage loop to automatically maintain the converter output voltage V. bus =V ref Simultaneously, the photovoltaic DC / DC converter controls the photovoltaic discharge voltage to be close to the bus voltage, maintaining the photovoltaic equipment at its maximum power point voltage while supplementing the power to the theoretical maximum value. Because energy storage and photovoltaics are directly coupled on the DC side, power losses caused by AC current conversion are significantly reduced. The entire system is as follows: Figure 3 As shown in the image.

[0082] Based on the above embodiments, as a preferred implementation, it also includes energy storage charging control: When the photovoltaic power generation is greater than the target output power, the corresponding energy storage charging strategy is executed according to the type of converter equipment in the DC-coupled photovoltaic power generation and storage system.

[0083] Among them, the type of converter equipment refers to the type of core equipment used for power conversion in the system. It is divided into unidirectional type, which can only invert DC power into AC power for grid connection; bidirectional type, which can realize bidirectional conversion of AC and DC power, can both invert and connect to the grid, and can also rectify AC grid power into DC to charge energy storage, such as energy storage converter. Bidirectional type, such as energy storage converter, is often used in the renovation of old photovoltaic projects, while new photovoltaic and energy storage projects are often equipped with bidirectional energy storage converter.

[0084] In this embodiment, the photovoltaic power generation is compared with the target output power in real time. When the former is detected to be greater than the latter (i.e., there is a power surplus), the specific type of the converter equipment in the system is first determined, and then a suitable energy storage charging strategy is selected accordingly. The core defect of the existing technology is that it does not consider the photovoltaic power surplus scenario. Either the surplus power is directly abandoned (causing energy waste), or a uniform charging strategy is adopted (such as drawing power from the grid for charging regardless of the converter equipment type), resulting in the inability to charge in the unidirectional inverter scenario and high charging costs in the bidirectional converter scenario. This step solves the technical problems of the inability to reasonably utilize the photovoltaic power surplus and the mismatch between the charging strategy and the converter equipment through the logic of power comparison-equipment judgment-strategy matching. It realizes the initial recovery of photovoltaic surplus power, avoids power abandonment loss, and ensures that the charging strategy is adapted to the characteristics of the equipment, laying the foundation for subsequent efficient charging.

[0085] If the converter is a unidirectional photovoltaic inverter, the overflow power during the photovoltaic power curtailment period is used to charge the energy storage battery.

[0086] Among them, the photovoltaic curtailment period refers to the specific time period during which the power grid restricts the output power of photovoltaic power plants due to low load, voltage stability requirements, or dispatch instructions; the overflow power refers to the portion of photovoltaic power generation that exceeds the target output power (curtailment power) during the photovoltaic curtailment period, i.e., "overflow power = photovoltaic power generation - target output power".

[0087] In this embodiment, when the system is configured with a unidirectional photovoltaic inverter (which cannot draw power in reverse), the overflow power is captured only during photovoltaic curtailment periods and directly transmitted to the energy storage battery through the shared DC bus to achieve energy storage charging. The drawback of the existing technology is that, for unidirectional inverter scenarios, the overflow power during curtailment periods can only be disposed of through power curtailment and cannot be stored and utilized, resulting in a large amount of energy waste and project revenue loss. This step solves the technical problem of severe power curtailment and power curtailment in unidirectional inverter scenarios by utilizing the overflow power during curtailment for charging, recovering the surplus energy during curtailment periods, increasing the energy storage battery's capacity, reducing power curtailment losses, and improving the overall power generation and revenue of the project.

[0088] If the converter is a bidirectional energy storage converter, it utilizes the overflow power during photovoltaic power curtailment and the off-peak electricity price period at night for charging, and sets the target output power to the maximum allowable input power of the energy storage converter during the off-peak electricity price period at night.

[0089] Among them, the off-peak electricity price period at night refers to the period when the power grid has low electricity load and sufficient power supply at night, and the electricity price is at its lowest level of the day (e.g., during this period P). mppt With P target (All are 0). For example, in most areas, 23:00-7:00 the next day is set as the off-peak period, and the electricity price is only 50% of the normal period price (e.g., 0.6 yuan / kWh during normal period and 0.3 yuan / kWh during off-peak period). The maximum allowable input power of the energy storage converter refers to the maximum AC input power that the bidirectional energy storage converter can safely withstand in rectification mode (to avoid overcurrent damage to the equipment) and ensure the safe operation of the equipment during charging.

[0090] In this embodiment, when the system is configured with a bidirectional energy storage converter, the charging sources are divided into two categories: the overflow power during photovoltaic curtailment (free energy) and the grid power during off-peak hours at night (low-cost energy); during off-peak hours at night, because photovoltaic power does not generate electricity (P... mppt =0), setting the system's target output power to the maximum allowable input power of the converter, enabling the converter to draw power from the grid at its maximum capacity for charging, thus maximizing the energy storage capacity. The drawback of existing technologies is that, for bidirectional converter scenarios, they only utilize the overflow power from power curtailment for charging, without taking into account off-peak electricity prices, resulting in insufficient energy storage charging capacity (unstable during power curtailment periods) and high charging costs (if power is drawn during flat-peak periods). This step solves the technical problems of insufficient energy storage charging capacity and high costs in bidirectional converter scenarios by using dual-source charging + full-power charging during off-peak periods. On the one hand, it reduces charging costs by using free overflow power, and on the other hand, it maximizes energy storage capacity by utilizing low-priced off-peak electricity (e.g., charging at 1.5MW power for 8 hours at night can store 12MWh of energy), providing sufficient power for daytime photovoltaic compensation, while reducing energy storage operating costs and further improving the project's economic benefits.

[0091] Secondly, embodiments of the present invention provide a compensation control system for a DC-coupled photovoltaic (PV) power generation and energy storage system. The PV power generation system includes a PV power generation unit, an energy storage unit, and a DC / AC inverter connected via a shared DC bus. The PV power generation unit includes a PV array and a maximum power point tracking (MPPT) DC / DC converter. The energy storage unit includes an energy storage battery and a bidirectional DC / DC converter. Based on the compensation control methods for the PV power generation and energy storage system described in the above examples, such as... Figure 4 As shown, the compensation control system includes: The data acquisition and processing module 410 is used to acquire measured solar radiation data and theoretical solar radiation data of the photovoltaic project site; The compensation parameter calculation module 420 is used to calculate the compensation parameter, which characterizes the photovoltaic power generation compensation ratio, based on the deviation between the measured solar radiation data and the theoretical solar radiation data. The capacity configuration module 430 is used to determine the average output power and configured capacity of the energy storage unit based on the compensation parameters. The real-time compensation coefficient calculation module 440 is used to calculate the real-time compensation coefficient based on the ratio of real-time measured solar radiation data to real-time theoretical solar radiation data during the operation of the DC-coupled photovoltaic power generation and storage system. The target power determination module 450 is used to determine the target output power of the DC-coupled photovoltaic power generation system based on the real-time compensation coefficient and the photovoltaic power generation. The energy storage power calculation module 460 is used to calculate the expected energy storage output power based on the difference between the target output power and the photovoltaic power generation power, combined with a dynamic correction factor. The charge / discharge control module 470 is used to generate an output current command for the energy storage battery based on the desired energy storage output power and the shared DC bus reference voltage, and to control the charging and discharging of the energy storage battery through the bidirectional DC / DC converter, so that the actual output power of the DC-coupled photovoltaic power distribution and storage system reaches the target output power.

[0092] Based on the same concept, this invention also provides a schematic diagram of a physical structure, such as... Figure 5 As shown, the server may include a processor 510, a communications interface 520, a memory 530, and a communication bus 540, wherein the processor 510, communications interface 520, and memory 530 communicate with each other via the communication bus 540. The processor 510 can call logical instructions in the memory 530 to execute the steps of the compensation control method for a DC-coupled photovoltaic power generation and storage system as described in the above embodiments.

[0093] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0094] Based on the same concept, embodiments of the present invention also provide a non-transitory computer-readable storage medium storing a computer program containing at least one piece of code that can be executed by a master control device to control the master control device to implement the steps of the compensation control method for a DC-coupled photovoltaic power distribution and storage system as described in the above embodiments.

[0095] Based on the same technical concept, this application also provides a computer program, which, when executed by a main control device, is used to implement the above-described method embodiments.

[0096] The program may be stored, in whole or in part, on a storage medium packaged with the processor, or in part or in whole on a memory not packaged with the processor.

[0097] Based on the same technical concept, this application also provides a processor for implementing the above-described method embodiments. The processor can be a chip.

[0098] The various embodiments of the present invention can be combined arbitrarily to achieve different technical effects.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A compensation control method for a DC-coupled photovoltaic (PV) power generation and energy storage system, the PV power generation and energy storage system comprising a PV power generation unit, an energy storage unit, and a DC / AC inverter connected via a shared DC bus, wherein the PV power generation unit comprises a PV array and a maximum power point tracking (MPPT) DC / DC converter, and the energy storage unit comprises an energy storage battery and a bidirectional DC / DC converter, characterized in that, The compensation control method includes: S1. Obtain measured solar radiation data and theoretical solar radiation data of the location of the photovoltaic project; S2. Based on the deviation between the measured solar radiation data and the theoretical solar radiation data, calculate the compensation parameters used to characterize the photovoltaic power generation compensation ratio; S3. Based on the compensation parameters, determine the average output power and configuration capacity of the energy storage unit; S4. During the operation of the DC-coupled photovoltaic power generation and storage system, calculate the real-time compensation coefficient based on the ratio of real-time measured solar radiation data to real-time theoretical solar radiation data. S5. Determine the target output power of the DC-coupled photovoltaic power generation system based on the real-time compensation coefficient and the photovoltaic power generation power. S6. Based on the difference between the target output power and the photovoltaic power generation, and combined with the dynamic correction factor, calculate the expected energy storage output power; S7. Based on the desired energy storage output power and the shared DC bus reference voltage, generate an output current command for the energy storage battery, and control the charging and discharging of the energy storage battery through the bidirectional DC / DC converter, so that the actual output power of the DC-coupled photovoltaic power distribution and storage system reaches the target output power.

2. The compensation control method for a DC-coupled photovoltaic power generation and storage system according to claim 1, characterized in that, In S1, the measured solar radiation data includes hourly solar radiation information for the project location over a year. The solar radiation information includes declination angle, hour angle, solar altitude angle, and solar incidence angle. The hour angle is calculated based on the longitude of the project location and the corresponding time zone. The solar altitude angle is calculated based on the latitude of the project location. The solar incidence angle is calculated based on the tilt angle, azimuth angle, and solar azimuth angle of the photovoltaic module.

3. The compensation control method for a DC-coupled photovoltaic power generation and storage system according to claim 1, characterized in that, S2 specifically includes: Using the hourly data of several locations at the photovoltaic project site throughout the year as the calculation period, the difference between the theoretical hourly solar radiation data and the actual hourly solar radiation data for the corresponding time period is calculated. The difference is divided by the actual hourly solar radiation data to obtain the gain ratio that the photovoltaic power generation needs to be supplemented in the hourly dimension. The gain ratio is defined as the compensation parameter.

4. The compensation control method for a DC-coupled photovoltaic power generation and storage system according to claim 3, characterized in that, S3 specifically includes: S31. Filter the hourly compensation parameters obtained in S2 and retain only the compensation parameters with positive values. S32. Calculate the arithmetic mean of all positive compensation parameters after screening, and multiply the average value by the preset rated operating power of the photovoltaic project to obtain the average output power that the energy storage unit needs to provide. S33. Multiply the average output power of the energy storage unit by the preset rated operating time of the photovoltaic project during the grid-allowed grid connection period to obtain the configured capacity of the energy storage unit.

5. The compensation control method for a DC-coupled photovoltaic power generation and storage system according to claim 1, characterized in that, In S5, the dynamic correction factor includes at least one of the following: inverter efficiency correction factor, battery state of charge (SOC) correction factor, temperature correction factor, battery health (SOH) correction factor, and fuzzy control correction factor. The inverter efficiency correction factor is determined based on the inverter's AC / DC conversion efficiency, and the inverter efficiency correction factor is the reciprocal of the inverter's conversion efficiency. The SOC correction factor adopts nonlinear quadratic curve control: a maximum SOC threshold and a minimum SOC threshold are set. When the SOC is less than or equal to the minimum SOC threshold, the SOC correction factor is 0 to limit battery discharge; when the SOC is greater than or equal to the maximum SOC threshold, the SOC correction factor is 1 to allow the battery to output full power. When SOC is between the maximum SOC threshold and the minimum SOC threshold, the SOC correction factor is calculated based on the difference between SOC and the maximum and minimum SOC thresholds. The temperature correction factor is based on 25°C: within the specified operating temperature range of the energy storage unit, for every 10°C deviation from the reference temperature, the battery efficiency decreases by 5%, and the temperature correction factor is calculated based on the difference between the actual operating temperature and the reference temperature. The SOH correction factor is linearly controlled within the set upper and lower limits of SOH; when SOH is lower than the set lower limit of SOH, the SOH correction factor limits the energy storage unit to output only 50% of its power. The control logic of the fuzzy control correction factor is as follows: based on the actual operating data of the energy storage unit and the preset system boundary conditions, the rule weights are set to dynamically adjust the expected energy storage output power.

6. The compensation control method for a DC-coupled photovoltaic power generation and storage system according to claim 1, characterized in that, In step S7, generating the output current command for the energy storage battery specifically includes: The output current value of the energy storage battery is calculated by dividing the desired energy storage output power by the shared DC bus reference voltage. Based on the output current value, the bidirectional DC / DC converter adopts a dual-loop control strategy of current inner loop and voltage outer loop to control the charging and discharging current of the battery, and controls and maintains the voltage of the shared DC bus at the reference voltage, so that the actual output power of the DC-coupled photovoltaic power generation and storage system reaches the target output power.

7. The compensation control method for a DC-coupled photovoltaic power generation and storage system according to claim 1, characterized in that, It also includes energy storage charging control: When the photovoltaic power generation is greater than the target output power, the corresponding energy storage charging strategy is executed according to the type of converter equipment in the DC-coupled photovoltaic power distribution and storage system. If the converter is a unidirectional photovoltaic inverter, the overflow power during the photovoltaic power curtailment period is used to charge the energy storage battery. If the converter is a bidirectional energy storage converter, it utilizes the overflow power during photovoltaic power curtailment and the off-peak electricity price period at night for charging, and sets the target output power to the maximum allowable input power of the energy storage converter during the off-peak electricity price period at night.

8. A compensation and control system for a DC-coupled photovoltaic (PV) power generation and energy storage system, the PV power generation and energy storage system comprising a PV power generation unit, an energy storage unit, and a DC / AC inverter connected via a shared DC bus, wherein the PV power generation unit comprises a PV array and a maximum power point tracking (MPPT) DC / DC converter, and the energy storage unit comprises an energy storage battery and a bidirectional DC / DC converter, characterized in that, The compensation control system includes: The data acquisition and processing module is used to acquire measured solar radiation data and theoretical solar radiation data of the photovoltaic project site; The compensation parameter calculation module is used to calculate the compensation parameters that characterize the photovoltaic power generation compensation ratio based on the deviation between the measured solar radiation data and the theoretical solar radiation data. The capacity configuration module is used to determine the average output power and configured capacity of the energy storage unit based on the compensation parameters. The real-time compensation coefficient calculation module is used to calculate the real-time compensation coefficient based on the ratio of real-time measured solar radiation data to real-time theoretical solar radiation data during the operation of the DC-coupled photovoltaic power generation and storage system. The target power determination module is used to determine the target output power of the DC-coupled photovoltaic power generation system based on the real-time compensation coefficient and the photovoltaic power generation. The energy storage power calculation module is used to calculate the expected energy storage output power based on the difference between the target output power and the photovoltaic power generation power, combined with a dynamic correction factor. The charge / discharge control module is used to generate an output current command for the energy storage battery based on the desired energy storage output power and the shared DC bus reference voltage, and to control the charging and discharging of the energy storage battery through the bidirectional DC / DC converter, so that the actual output power of the DC-coupled photovoltaic power distribution and storage system reaches the target output power.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the compensation control method for a DC-coupled photovoltaic power generation and storage system as described in any one of claims 1 to 7.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the compensation control method for a DC-coupled photovoltaic power generation and storage system as described in any one of claims 1 to 7.

Images