A hybrid AC / DC side energy storage device for a photovoltaic power station and a differential configuration method

Abstract

The present invention discloses a hybrid AC-DC side energy storage device and a differential configuration method for a photovoltaic power station. It includes a photovoltaic string, a DC busbar box, a DC side energy storage device, a centralized inverter-booster integrated machine, and an AC side energy storage device; the DC busbar box is used to collect the electric energy generated by multiple photovoltaic strings to the low-voltage side of the centralized inverter-booster integrated machine, the DC side energy storage device is connected to the low-voltage side of the centralized inverter-booster integrated machine, the AC side energy storage device is connected to the collector line bus through a transformer, the high-voltage side of the centralized inverter-booster integrated machine is connected to the collector line bus, and the collector line bus is connected and output through a main transformer and a transmission line. The present invention effectively improves the power generation efficiency of the photovoltaic power station, reduces the investment cost of the photovoltaic power station, and improves the service life of energy storage batteries.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaic power generation and energy storage, and specifically relates to a hybrid AC-DC side energy storage device for a photovoltaic power station and a differential configuration method thereof. Background Art

[0002] At present, the energy storage battery configuration of photovoltaic power stations is relatively single, and the advantages of different types of energy storage batteries are not fully utilized, nor are different types of energy storage batteries configured according to the functional requirements of energy storage batteries. In addition, existing energy storage devices are basically configured on the collector line bus or the DC side, and the advantages of the AC-DC hybrid differential configuration of energy storage devices are not fully utilized.

[0003] For example, Patent CN114094608A proposes a multi-type energy storage capacity optimization configuration method and device for a photovoltaic power station. Although it also considers the configuration of multiple types of energy storage devices and functional complementarity, it does not propose a multi-type energy storage configuration method by combining the different advantages and main functions of AC-DC side energy storage configurations.

[0004] For example, Patent CN207069602U proposes a DC side distributed energy storage system for a photovoltaic power station, and gives a configuration scheme for DC side energy storage, but does not propose the basic principles and methods for AC-DC side energy storage configuration in combination with existing energy storage policies.

[0005] Another example is Patent CN114006405A, which proposes an inverter DC side coupled energy storage system and a photovoltaic capacity ratio and energy storage configuration method. Although it considers DC side energy storage and coordinated design with the photovoltaic capacity ratio of a photovoltaic power station, it does not give a specific configuration method and the principles and methods for cooperation with AC side energy storage.

[0006] Therefore, it is necessary to propose a hybrid AC-DC side energy storage device for a photovoltaic power station and a differential configuration method, combining the functions and advantages of different types of energy storage devices. Summary of the Invention

[0007] The purpose of the present invention is to provide a hybrid AC-DC side energy storage device for a photovoltaic power station and a differential configuration method, aiming at the fundamental defect that the existing energy storage device configuration of a photovoltaic power station does not fully utilize the advantages of different types of energy storage batteries, nor does it differentially configure different types of energy storage batteries on the AC-DC sides of the photovoltaic power station according to the functional requirements of the energy storage batteries.

[0008] The technical solution adopted by the present invention is as follows: A hybrid AC-DC side energy storage device and a differential configuration method for a photovoltaic power station, including photovoltaic strings, a DC busbar box, a DC side energy storage device, a centralized inverter-booster integrated machine, and an AC side energy storage device; the DC busbar box is used to collect the electric energy generated by multiple photovoltaic strings to the low-voltage side of the centralized inverter-booster integrated machine, the DC side energy storage device is connected to the low-voltage side of the centralized inverter-booster integrated machine, the AC side energy storage device is connected to the collector line bus through a transformer, the high-voltage side of the centralized inverter-booster integrated machine is connected to the collector line bus, and the collector line bus is connected and output through a main transformer and a transmission line.

[0009] The photovoltaic power station consists of several photovoltaic arrays, and each photovoltaic array includes photovoltaic strings, a DC busbar box, and a centralized inverter-booster integrated machine. The photovoltaic strings are formed by connecting photovoltaic cells in series.

[0010] The DC side energy storage device includes a DC side controller and a DC side energy storage battery. The DC side energy storage controller is used to control the storage and release of energy in the DC side energy storage battery.

[0011] The DC side energy storage battery is selected from lithium-ion batteries, lead-acid batteries, sodium-sulfur batteries, or flow batteries, mainly for storing and releasing the electric energy generated by the photovoltaic strings, and supplemented by functions such as primary frequency modulation.

[0012] The centralized inverter-booster integrated machine includes an inverter and a box-type substation, and is used to convert the direct current generated by multiple DC busbar boxes and the DC side energy storage device into alternating current, boost it, and then connect it to the collector line bus.

[0013] The AC side energy storage device includes an AC side controller and an AC side energy storage battery. The AC side controller is used to control the storage and release of energy in the AC side energy storage battery.

[0014] The AC side energy storage battery is selected from flywheel energy storage or supercapacitors, mainly for functions such as primary frequency modulation, and supplemented by storing and releasing the electric energy generated by the photovoltaic strings.

[0015] The alternating current collected by the collector line bus is boosted by the main transformer and then sent to the power grid through the transmission line.

[0016] A differential configuration method for a hybrid AC-DC side energy storage device of a photovoltaic power station includes

[0017] The configuration rule for the capacity of the DC side energy storage battery is to avoid the power loss caused by over-allocation on the DC side through the DC side energy storage device. The specific configuration is as follows:

[0018] The power P of the DC side energy storage battery DC The configuration needs to meet the following formula:

[0019]

[0020] Among them, P 0j is the AC-side power of the j-th centralized inverter and boost integrated machine; r j is the designed capacity ratio of the j-th PV array; η j is the DC-side loss of the j-th PV array; N is the number of PV arrays in the PV power station;

[0021] Select the day with the best power generation benefit in a year for the PV power station, and calculate the DC-side power generation power P i of the PV strings in the PV array during the time t when it is greater than the AC-side power P0. Then, the capacity Q DC of the DC-side energy storage battery needs to meet the following requirements:

[0022]

[0023] Among them, P ij is the DC-side power generation power of the first PV array;

[0024] The configuration rule of the AC-side energy storage battery meets at least half of the primary frequency regulation capacity demand and, together with the DC-side energy storage, meets the minimum energy storage configuration requirements of the PV power station. The specific configuration is as follows:

[0025] Assume that the energy storage configuration requirement at the location of the PV power station is not less than m% / t of the installed capacity. According to the total installed capacity of the PV power station, the minimum configured power P c and capacity Q c of the energy storage are obtained: c :

[0026]

[0027] Assume that the system frequency fluctuation detected by the PV power station is △f, and the maximum fluctuation duration within a day is t f , and the droop controller parameter of the PV power station is k f . Then, the maximum primary frequency regulation power of the PV power station is P f and the maximum capacity Q f are as follows:

[0028]

[0029] The AC-side energy storage power P AC and capacity Q AC of the PV power station are obtained:

[0030]

[0031] The energy storage battery on the DC side of the present invention mainly selects energy storage batteries with high energy density, mainly for energy storage and release, and supplemented by functions such as primary frequency modulation. The capacity of the energy storage device on the DC side is jointly determined by the AC-side power P0 of the photovoltaic array, the capacity ratio r, the DC-side loss η of the photovoltaic array, etc. The configuration principle of the energy storage device on the DC side is to ensure that the excess power generated by the photovoltaic modules is not lost due to the power limitation of the inverter, and mainly for energy storage. It only participates in functions such as primary frequency modulation when the primary frequency modulation capacity of the AC-side energy storage device is insufficient.

[0032] The energy storage battery on the AC side mainly selects energy storage batteries with high power density and long cycle life, mainly for functions such as primary frequency modulation, and supplemented by energy storage and release.

[0033] The capacity of the energy storage device on the AC side of the photovoltaic power station is jointly determined by the maximum power P f required for primary frequency modulation of the system and the maximum capacity Q f , and the requirements for energy storage configuration of photovoltaic power stations in each province and city. Its configuration principle is to meet at least 50% of the primary frequency modulation capacity required by the system, and after cooperating with the energy storage device on the DC side, it needs to meet the minimum requirements for energy storage configuration of photovoltaic power stations in each province and city. The energy storage device on the AC side gives priority to participating in the system's primary frequency modulation and other requirements, and only participates in functions such as energy storage and release when the energy storage and release of the energy storage device on the DC side are insufficient.

[0034] The present invention sets different types of energy storage devices on the DC side and AC side of the photovoltaic power station respectively. Among them, the energy storage device on the DC side mainly focuses on energy storage and release, and is supplemented by functions such as primary frequency modulation. The energy storage battery on the DC side generally selects electrochemical energy storage batteries such as lithium-ion batteries, lead-acid batteries, sodium-sulfur batteries, and flow batteries.

[0035] The energy storage device on the AC side mainly focuses on functions such as primary frequency modulation, and is supplemented by energy storage and release. The energy storage battery on the AC side generally selects flywheel energy storage or supercapacitors, giving full play to the advantages of different energy storage devices and the different advantages of energy storage on the AC and DC sides. The present invention effectively improves the power generation efficiency of the photovoltaic power station, reduces the investment cost of the photovoltaic power station, and extends the service life of the energy storage battery.

[0036] Compared with the prior art, the present invention can achieve the following specific beneficial effects:

[0037] 1. The present invention disperses the energy storage device on the DC side on the DC side of the photovoltaic power station, reducing the risk of collective fire of the energy storage device and improving the safety and reliability of the energy storage device of the photovoltaic power station.

[0038] 2. It can effectively improve the capacity ratio of the photovoltaic power station. If 10% of the energy storage battery is configured on the DC side, the capacity ratio of the photovoltaic power station can be increased by about 10%. In addition, the present invention can also reduce the power loss caused by over-sizing of the photovoltaic power station, and improve the power generation efficiency of the photovoltaic power station by about 1 - 3%.

[0039] 3. The DC-side energy storage device shares the box inverter integrated machine with the PV string, which can improve the utilization rate of AC equipment and cables, save the investment cost of energy storage configuration for PV projects. Calculated according to the configuration of 10% / 2h energy storage for every 100MW PV project, the present invention can save 2 million yuan in investment compared with the traditional energy storage configuration method.

[0040] 4. The AC-side energy storage device uses energy storage batteries with a long cycle life, undertakes most of the tasks such as primary frequency modulation, and can effectively reduce the charge and discharge times of the DC-side energy storage device, thereby increasing the life of the DC-side energy storage battery. Brief Description of the Drawings

[0041] Figure 1 It is the structure diagram of the AC-DC hybrid energy storage device in the PV power station;

[0042] Figure 2 It is the schematic diagram of the DC-side energy storage controller (DC / DC converter);

[0043] Figure 3 It is the schematic diagram of the AC-side energy storage controller (DC / AC converter).

[0044] In the figure, 1 - PV string, 2 - DC busbar box, 3 - DC-side energy storage device, 31 - DC-side energy storage controller, 32 - DC-side energy storage battery, 4 - centralized inverter and boost integrated machine, 5 - AC-side energy storage device, 51 - AC-side energy storage controller, 52 - AC-side energy storage battery, 6 - transformer, 7 - collector line busbar, 8 - main transformer, 9 - outgoing line. Detailed Embodiment

[0045] The following further elaborates on the present invention in detail in conjunction with the drawings and specific embodiments, which is convenient for clearly understanding the present invention, but they do not constitute a limitation to the present invention.

[0046] As Figure 1 shown, the present invention includes a PV string 1, a DC busbar box 2, a DC-side energy storage device 3, a centralized inverter and boost integrated machine 4, an AC-side energy storage device 5, a main transformer 8, and an outgoing line 9.

[0047] Among them, the DC busbar box 2 is used to collect multiple PV strings 1 to the low-voltage side of the centralized inverter and boost integrated machine 4. The DC busbar box 2 has various types of busbar boxes such as 16-in-1 and 24-in-1. The DC busbar box 2 is selected according to parameters such as the PV array ratio, component parameters, and the centralized inverter and boost integrated machine 4.

[0048] The PV string 1 is composed of PV cells connected in series and can be designed according to the specification "Code for Design of Photovoltaic Power Stations" GB 50797-2012.

[0049] The DC-side energy storage device 3 includes a DC-side controller 31 and a DC-side energy storage battery 32. The DC-side energy storage controller 31 is used to control the storage and release of energy in the DC-side energy storage battery 32.

[0050] The centralized inverter-booster integrated unit 4 includes an inverter and a box-type substation, and is used to convert the direct current generated by multiple DC busbars 2 and the DC-side energy storage device 3 into alternating current, boost the voltage, and then connect it to the collector line bus 7.

[0051] The AC-side energy storage device 5 includes an AC-side energy storage controller 51 and an AC-side energy storage battery 52. The AC-side energy storage controller 51 is used to control the storage and release of energy in the AC-side energy storage battery 52.

[0052] The alternating current collected by the collector line bus 7 is boosted by the main transformer 8 and then sent to the power grid through the outgoing line 9.

[0053] The capacity ratio refers to the ratio of the power of the photovoltaic modules to the rated power of the inverter. Due to the attenuation of the component power, dust shading, and line losses in the photovoltaic system, and the differences in lighting conditions in different regions, only considering the rated input power limit of the inverter when designing and configuring the power of the photovoltaic modules in the system will reduce the economy of the system. Therefore, generally, according to the lighting resources, system losses, component installation methods, and tilts of the project, the system capacity ratio is reasonably optimized to further reduce the cost per kilowatt-hour of the system. The maximum limit of the ratio of components to the inverter is 1.8:1. Among them, in the first-class solar resource areas, the capacity ratio should not exceed 1.2; in the second-class solar resource areas, the capacity ratio should not exceed 1.4; in the third-class solar resource areas, the capacity ratio should not exceed 1.8.

[0054] The capacity configuration rule of the DC-side energy storage battery 32 is to avoid the power loss caused by over-sizing on the DC side through the DC-side energy storage device 3. The specific configuration is as follows:

[0055] 1) Assume that the AC-side power of the jth centralized inverter-booster integrated unit 4 is P 0j , the designed capacity ratio of the jth photovoltaic array is r j , the DC-side loss (power loss from the photovoltaic string 1 to the centralized inverter-booster integrated unit 4) of the jth photovoltaic array is η j . To avoid over-sizing power loss on the DC side, the power P DC of the DC-side energy storage battery 32 needs to satisfy the following formula:

[0056]

[0057] Among them, P 0j is the AC-side power of the jth centralized inverter-booster integrated unit (4); r j is the designed capacity ratio of the jth photovoltaic array; η jis the DC-side loss of the j-th PV array; N is the number of PV arrays in the PV power station;

[0058] 2) Select the day with the best power generation benefit in a year for the PV power station, and calculate the DC-side power generation power P of the PV string 1 in the PV array i For the over-generated electric energy during the time t when it is greater than the AC-side power P0, the capacity Q of the DC-side energy storage battery DC shall meet the following requirements:

[0059]

[0060] where P ij is the DC-side power generation power of the first PV array;

[0061] 3) According to the power demand and capacity demand of the DC-side energy storage configuration, the DC-side energy storage battery 32 can be selected. The DC-side energy storage battery 32 mainly selects energy storage batteries with high energy density, such as lithium iron phosphate, sodium-ion batteries, redox flow batteries and other electrochemical energy storage batteries, mainly for energy storage and release, supplemented by functions such as primary frequency modulation. When the primary frequency modulation ability of the AC-side energy storage is insufficient, the DC-side energy storage device will participate in the system primary frequency modulation, so as to avoid the frequent operation of the DC-side energy storage battery and reduce its lifespan.

[0062] Generally speaking, in order to avoid the loss of electric energy generated by PV modules due to the limitation of inverters or box transformers, the PV power station capacity ratio is generally taken around 1.1 / (1 - η j ), that is, the electric energy generated by PV modules can finally be sent out through the inverter. If the capacity ratio is further increased, the electric energy generated by PV modules will be limited and lost by the inverter. Configuring energy storage on the DC side can further increase the capacity ratio of the PV power station, that is, the extra electric energy generated by the modules can be stored in the energy storage battery first, and then released when the power output of the PV modules is less than the power limit of the inverter and the box transformer. If 10% of the energy storage battery is configured on the DC side, the capacity ratio of the PV power station can be increased by about 10%.

[0063] When the DC-side power generation power of the integrated box inverter is greater than the AC-side power generation power, the DC-side energy storage controller stores the excess electric energy in the DC-side energy storage battery; when the DC-side power generation power of the integrated box inverter is less than the AC-side power output of the centralized inverter and booster and there is a power demand, the DC-side energy storage controller releases the energy in the DC-side energy storage battery.

[0064] The topology of the DC-side energy storage controller 31 is shown in Figure 2As shown. By controlling the on and off of the MOSFET tube, the output voltage can be controlled, thereby controlling the inflow and outflow of energy. When the output DC voltage is greater than the input DC voltage, energy flows in; when the output DC voltage is less than the input DC voltage, energy flows out. The ratio of the output DC voltage to the input DC voltage is related to the duty cycle.

[0065] The DC side energy storage device 3 is dispersedly arranged on the DC side of the photovoltaic power station, which reduces the risk of collective fire of the energy storage device, can effectively improve the capacity ratio of the photovoltaic power station, reduce the power loss caused by the over-allocation of the photovoltaic power station, and improve the power generation efficiency of the photovoltaic power station by about 1 to 3%. In addition, the DC side energy storage device and the photovoltaic string share the box inverter 4, which can improve the utilization rate of AC equipment and cables, save the investment cost of energy storage configuration of photovoltaic projects, and calculate according to the configuration of 10% / 2h energy storage for every 100MW photovoltaic project. Compared with the traditional energy storage configuration method, the present invention can save about 2 million yuan.

[0066] The configuration rule of the AC side energy storage battery 52 meets at least half of the primary frequency regulation capacity requirements, and together with the DC side energy storage, meets the minimum energy storage configuration requirements of the photovoltaic power station. The specific configuration is as follows:

[0067] 1) Configure according to the minimum energy storage configuration requirements of photovoltaic power stations: Generally, provinces and cities have certain requirements for the energy storage configuration of photovoltaic power stations. For example, Jiangxi Province requires that new energy be configured with energy storage devices that are not less than 10% / 1 hour of installed capacity, and Shandong Province requires that new energy be configured with energy storage devices that are not less than 10% / 2 hours of installed capacity. Assuming that the energy storage configuration requirements for the location of the photovoltaic power station are not less than m% / t of the installed capacity c hours, the minimum energy storage configuration power P can be obtained based on the total installed capacity of the photovoltaic power station c and capacity Q c , as shown below:

[0068]

[0069] So we can get the AC side energy storage power P of the photovoltaic power station AC and capacity Q AC :

[0070]

[0071] 2) Configuration according to the system's primary frequency regulation requirements: Shandong, Fujian, and some areas in the Northeast require energy storage to participate in the system's primary frequency regulation. The photovoltaic power station will adjust its input system active power according to the system frequency fluctuation, that is, participate in the system's primary frequency regulation. Assuming that the system frequency fluctuation detected by the photovoltaic power station is △f, and the maximum fluctuation duration in a day is t f , the PV power station droop controller parameter is k f , then the maximum power of the photovoltaic power station is P fand the maximum capacity Q f as follows:

[0072]

[0073] Then the energy storage power P on the AC side of the PV power station can be obtained AC and the capacity Q AC :

[0074]

[0075] That is, the energy storage device on the AC side should at least meet half of the primary frequency regulation capacity requirement, and after cooperating with the energy storage device on the DC side, it should meet the minimum requirements for the energy storage configuration of PV power stations in each province and city. Generally speaking, the energy storage battery participates in the primary frequency regulation action thousands of times a day, and the number of deep frequency regulation (more than 50% capacity) is only about a hundred times. The energy storage device on the AC side gives priority to participating in primary frequency regulation, which can greatly reduce the charge and discharge times of the energy storage battery on the DC side, thus extending the service life of the energy storage device on the DC side.

[0076] The energy storage controller 51 on the AC side, such as Figure 3 shown, is mainly composed of hardware such as IGBT and filters. The controller mainly includes a phase-locked loop, a DC voltage controller, and an AC current controller. The charge and discharge of the energy storage battery on the AC side can be controlled through the DC voltage control and the AC current controller.

[0077] The energy storage battery 52 on the AC side mainly selects energy storage batteries with high power density and long cycle life, such as flywheel energy storage batteries. The energy storage device on the AC side mainly functions as primary frequency regulation, supplemented by energy storage and release. When the system has a primary frequency regulation requirement, the energy storage controller on the AC side will control the energy storage device on the AC side to participate in the system's primary frequency regulation. In addition, when the power of the collector line bus is greater than the power transmitted from the PV power station, the energy storage controller on the AC side will store the excess electric energy in the energy storage battery on the AC side; when the power of the collector line bus is less than the power transmitted from the PV power station, the energy storage controller on the AC side will release the excess electric energy.

[0078] The present invention sets different types of energy storage devices on the DC side and AC side of the photovoltaic power station, respectively, combines the advantages of different types of energy storage devices, and gives full play to the different functions of the AC and DC side energy storage devices. The configuration principle of the DC side energy storage device is to ensure that the over-generated energy of the photovoltaic module is not lost due to the power limitation of the inverter, and only participates in the primary frequency regulation of the system when the primary frequency regulation capacity of the AC side energy storage device is insufficient. The configuration principle of the AC side energy storage device is to at least meet 50% of the primary frequency regulation capacity required by the system, and after cooperating with the DC side energy storage device, it can meet the minimum requirements of various provinces and cities for the energy storage configuration of photovoltaic power stations. The present invention disperses the DC side energy storage devices on the DC side of the photovoltaic power station, reduces the risk of collective fire of the energy storage devices, can effectively improve the capacity ratio of the photovoltaic power station, reduce the power loss caused by the over-allocation of the photovoltaic power station, and improve the power generation efficiency of the photovoltaic power station by about 1 to 3%. In addition, the DC side energy storage device and the photovoltaic string common box inverter can improve the utilization rate of AC equipment and cables, save the investment cost of photovoltaic project energy storage configuration, and calculate according to the configuration of 10% / 2h energy storage for every 100MW photovoltaic project. Compared with the traditional energy storage configuration method, the present invention can save 2 million yuan in investment. At the same time, the AC side energy storage device uses energy storage batteries with long cycle life, which are mainly used for primary frequency modulation and other functions, which can effectively reduce the number of charge and discharge times of the DC side energy storage device, thereby increasing the life of the DC side energy storage battery.

[0079] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A hybrid AC-DC side energy storage device for a photovoltaic power station, characterized in that: It includes a photovoltaic string (1), a DC busbar collector (2), a DC-side energy storage device (3), a centralized inverter-booster integrated unit (4), and an AC-side energy storage device (5); the DC busbar collector (2) is used to collect the electric energy generated by multiple photovoltaic strings (1) to the low-voltage side of the centralized inverter-booster integrated unit (4), the DC-side energy storage device (3) is connected to the low-voltage side of the centralized inverter-booster integrated unit (4), the AC-side energy storage device (5) is connected to the collector line busbar (7) via a transformer (6), the high-voltage side of the centralized inverter-booster integrated unit (4) is connected to the collector line busbar (7), and the collector line busbar (7) is connected and output through a main transformer (8) and a transmission line (9); The photovoltaic power station consists of several photovoltaic arrays, and each photovoltaic array includes a photovoltaic string (1), a DC busbar collector (2), and a centralized inverter-booster integrated unit (4), and the photovoltaic string (1) is formed by connecting photovoltaic cells in series; The DC-side energy storage device (3) includes a DC-side energy storage controller (31) and a DC-side energy storage battery (32), and the DC-side energy storage controller (31) is used to control the storage and release of energy of the DC-side energy storage battery (32); The DC-side energy storage battery (32) is selected from lithium-ion batteries, lead-acid batteries, sodium-sulfur batteries, or flow batteries, mainly for storing and releasing the electric energy generated by the photovoltaic string, and supplemented by functions such as primary frequency modulation; The AC-side energy storage device (5) includes an AC-side energy storage controller (51) and an AC-side energy storage battery (52), and the AC-side energy storage controller (51) is used to control the storage and release of energy in the AC-side energy storage battery (52); The AC-side energy storage battery (52) is selected from flywheel energy storage or supercapacitors, mainly for functions such as primary frequency modulation, and supplemented by storing and releasing the electric energy generated by the photovoltaic string; The differential configuration method of the AC-DC hybrid energy storage device of the photovoltaic power station includes The capacity configuration rule of the DC-side energy storage battery (32) is to avoid the power loss caused by over-configuration on the DC side through the DC-side energy storage device (3), and the specific configuration is as follows: The power P of the DC-side energy storage battery (32) DC The configuration needs to satisfy the following formula: Among them, P 0j is the AC-side power of the j-th centralized inverter-booster integrated unit (4); r j is the design capacity ratio of the j-th photovoltaic array; η j is the DC-side loss of the j-th photovoltaic array; N is the number of photovoltaic arrays in the photovoltaic power station; Select the day with the best power generation benefit in a year for a photovoltaic power station, and calculate the DC-side power generation power P of the photovoltaic string (1) in the photovoltaic array i For the excess electric energy generated during the time t when it is greater than the AC-side power P0, the capacity Q of the DC-side energy storage battery (32) DC Needs to satisfy: Among them, P ij is the DC-side power generation power of the first photovoltaic array; The configuration rule of the AC-side energy storage battery (52) meets at least half of the primary frequency modulation capacity requirements, and together with the DC-side energy storage, meets the minimum energy storage configuration requirements of the photovoltaic power station, and the specific configuration is as follows: Assume that the energy storage configuration requirement at the location of the PV power station is not less than m% / t of the installed capacity c per hour. According to the total installed capacity of the PV power station, the minimum configured power P c and capacity Q c are obtained as follows: Suppose the system frequency fluctuation detected by the PV power station is △f, and the maximum fluctuation duration within a day is t f , and the droop controller parameter of the PV power station is k f , then the maximum primary frequency regulation power of the PV power station is P f and the maximum capacity Q f : Obtain the AC-side energy storage power P of the photovoltaic power station AC and the capacity Q AC :

2. The AC-DC hybrid energy storage device for a photovoltaic power station according to claim 1, characterized in that: The centralized inverter-booster integrated unit (4) includes an inverter and a box-type substation, and is used to convert the direct current generated by multiple DC busbar collectors (2) and the DC-side energy storage device (3) into alternating current, boost it, and then connect it to the collector line busbar (7).

3. A hybrid AC / DC side energy storage device for a photovoltaic power station according to claim 1, characterized in that: The alternating current collected by the collector line busbar (7) is boosted by the main transformer (8) and sent to the power grid through the transmission line (9).

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