A method, system, device and medium for constructing the main circuit of a battery energy storage power station

Abstract

The present invention discloses a method, system, device and medium for constructing a main circuit of a battery energy storage power station. By selecting target battery monomers according to the capacity requirement information of the energy storage power station, combining with the maximum operating voltage of the target battery monomers, determining the battery quantity information of the target battery monomers, and combining the capacity requirement information of the energy storage power station and the battery monomer parameters corresponding to the target battery monomers, the total number of initial H-bridge modules is determined. Based on the preset grid connection parameters and the total number of initial H-bridge modules, the total number of H-bridge modules and the parallel connection quantity of the cascaded multilevel energy storage converters are determined, and the main circuit of the battery energy storage power station is constructed in combination with the battery quantity information. The present invention calculates the required number of target battery monomers, the total number of H-bridge modules and the parallel connection quantity of the cascaded multilevel energy storage converters according to information such as the capacity requirement of the energy storage power station and the grid connection parameters, meeting the technical requirements of the main circuit of the battery energy storage power station based on the cascaded multilevel topology.

Description

Technical Field

[0001] The present invention relates to the technical field of the main circuit construction of a battery energy storage power station, and particularly relates to a method, a system, a device, and a medium for constructing the main circuit of a battery energy storage power station. Background Art

[0002] The battery energy storage system responds quickly and is flexible to adjust. It can be applied to all aspects of power generation, transmission, distribution, and use in the power system, and can effectively solve the power balance problem and system stability risk caused by the large-scale grid connection of new energy. The capacity level of a single-stage cascaded multi-level battery energy storage system is about 10 MWh, while the maximum capacity of a conventional centralized low-voltage energy storage system based on two-level or three-level is only 1 MWh. For a future battery energy storage power station with a scale of up to several hundred megawatt-hours, compared with the conventional centralized low-voltage topology, adopting the topology of a cascaded multi-level battery converter as the energy storage power converter can greatly reduce the number of parallel power converters and effectively avoid problems such as resonance caused by multi-machine parallel connection.

[0003] Currently, the commonly used main circuit design method for a battery energy storage power station is applicable to a conventional low-voltage energy storage system based on two-level or three-level. Due to the differences in the main circuit topology structure, this method cannot be directly applied to a battery energy storage power station based on a cascaded multi-level topology, and there are few reports on the main circuit design method for a battery energy storage power station based on a cascaded multi-level topology. Summary of the Invention

[0004] The present invention provides a method, a system, a device, and a medium for constructing the main circuit of a battery energy storage power station, and solves the technical problem of the lack of a main circuit construction method for a battery energy storage power station based on a cascaded multi-level topology at present.

[0005] A method for constructing the main circuit of a battery energy storage power station provided by the present invention includes:

[0006] When receiving the energy storage power station capacity requirement information, select the target battery monomer according to the energy storage power station capacity requirement information;

[0007] Based on the maximum operating voltage corresponding to the target battery monomer and the energy storage power station capacity requirement information, determine the battery quantity information of the target battery monomer;

[0008] According to the battery quantity information, the energy storage power station capacity requirement information, and the battery monomer parameters corresponding to the target battery monomer, determine the total number of initial H-bridge modules;

[0009] According to the preset grid connection parameters and the total number of initial H-bridge modules, determine the number of H-bridge modules required for a single cascaded multi-level energy storage converter, the total number of H-bridge modules, and the number of parallel cascaded multi-level energy storage converters;

[0010] Construct the main circuit of the battery energy storage power station based on the cascaded multilevel topology by using H-bridge modules corresponding to the total number of the H-bridge modules and target battery cells corresponding to the battery quantity information, in combination with the parallel connection quantity of the cascaded multilevel energy storage converter and the number of the H-bridge modules.

[0011] Optionally, the energy storage power station capacity requirement information includes the total capacity of the energy storage power station, the power of the power station, the voltage information of the preset power semiconductor device, and the number information of the battery cell interfaces; the step of determining the battery quantity information of the target battery cell based on the maximum operating voltage corresponding to the target battery cell and the energy storage power station capacity requirement information includes:

[0012] Calculate the ratio of the total capacity of the energy storage power station to the power of the power station to obtain the discharge duration of the battery energy storage power station;

[0013] Determine the number of parallel battery branches corresponding to the target battery cell according to the discharge duration;

[0014] Determine the number of series-connected battery cells in a single path corresponding to the target battery cell according to the voltage information of the preset power semiconductor device, the maximum operating voltage corresponding to the target battery cell, and the number information of the battery cell interfaces.

[0015] Optionally, the step of determining the number of parallel battery branches corresponding to the target battery cell according to the discharge duration includes:

[0016] Use the discharge duration as a keyword to match the corresponding target application scenario from the preset scenario information table;

[0017] Determine the number of parallel battery branches corresponding to the target application scenario as the number of parallel battery branches corresponding to the target battery cell.

[0018] Optionally, the voltage information of the preset power semiconductor device includes the rated voltage of the preset power semiconductor device and the voltage margin of the preset power semiconductor device; the step of determining the number of series-connected battery cells in a single path corresponding to the target battery cell according to the voltage information of the preset power semiconductor device, the maximum operating voltage corresponding to the target battery cell, and the number information of the battery cell interfaces includes:

[0019] Calculate the ratio of the rated voltage of the preset power semiconductor device, the voltage margin of the preset power semiconductor device, and the maximum operating voltage corresponding to the target battery cell to obtain the initial number of series-connected battery cells in a single path;

[0020] Select the smallest multiple value greater than the initial number of series-connected battery cells in a single path from the multiple values corresponding to the number information of the battery cell interfaces;

[0021] Determine the minimum multiple value as the number of single - path series battery monomers corresponding to the target battery monomer.

[0022] Optionally, the battery monomer parameters include the rated voltage of the battery monomer and the capacity of the battery monomer; the step of determining the total number of initial H - bridge modules according to the battery quantity information, the energy storage power station capacity demand information, and the battery monomer parameters corresponding to the target battery monomer includes:

[0023] Calculate the battery quantity information, the rated voltage of the battery monomer, and the capacity of the battery monomer to obtain the rated module capacity corresponding to a single H - bridge module.

[0024] Calculate the ratio of the total energy storage power station capacity corresponding to the energy storage power station capacity demand information to the rated module capacity to determine the total number of initial H - bridge modules.

[0025] Optionally, the step of determining the number of H - bridge modules required for a single - stage cascaded multilevel energy storage converter, the total number of H - bridge modules, and the number of parallel single - stage cascaded multilevel energy storage converters according to the preset grid connection parameters and the total number of initial H - bridge modules includes:

[0026] Substitute the preset grid connection parameters into the formula for calculating the number of single - phase H - bridge modules of a preset single - stage cascaded multilevel energy storage converter to determine the number of H - bridge modules required for a single - stage cascaded multilevel energy storage converter.

[0027] Calculate the ratio of the total number of initial H - bridge modules to the number of H - bridge modules to obtain a module ratio.

[0028] Perform a rounding - down operation on the module ratio to obtain the downward - rounded number of parallel single - stage cascaded multilevel energy storage converters and the upward - rounded number of parallel single - stage cascaded multilevel energy storage converters.

[0029] Calculate the total number of actual H - bridge modules required for the downward - rounded number of parallel single - stage cascaded multilevel energy storage converters to obtain a corresponding first initial number.

[0030] Calculate the total number of actual H - bridge modules required for the upward - rounded number of parallel single - stage cascaded multilevel energy storage converters to obtain a second initial number.

[0031] Compare the first initial number with the second initial number.

[0032] If the first initial number is greater than the second initial number, then use the second initial number as the total number of H - bridge modules and the upward - rounded number of parallel single - stage cascaded multilevel energy storage converters as the number of parallel single - stage cascaded multilevel energy storage converters.

[0033] If the first initial quantity is less than the second initial quantity, then use the first initial quantity as the total number of H-bridge modules, and use the downward-rounded cascaded multilevel energy storage converter parallel quantity as the cascaded multilevel energy storage converter parallel quantity.

[0034] Optionally, the step of constructing the main circuit of the battery energy storage power station based on the cascaded multilevel topology by using H-bridge modules corresponding to the total number of H-bridge modules and target battery cells corresponding to the battery quantity information, in combination with the cascaded multilevel energy storage converter parallel quantity and the number of H-bridge modules, includes:

[0035] Use the target battery cells corresponding to the single-path series battery cell quantity to construct a battery branch;

[0036] Select H-bridge modules corresponding to the total number of H-bridge modules;

[0037] Connect the battery branches to the DC sides of the respective H-bridge modules according to the parallel battery branch quantity, and combine with the number of H-bridge modules to obtain a single cascaded multilevel energy storage converter;

[0038] Parallel the respective cascaded multilevel energy storage converters according to the cascaded multilevel energy storage converter parallel quantity, and connect to the bus corresponding to the battery energy storage power station to obtain the main circuit of the battery energy storage power station.

[0039] The present invention also provides a system for constructing the main circuit of a battery energy storage power station, including:

[0040] A target battery cell selection module, configured to select the type of target battery cells according to the energy storage power station capacity demand information when receiving the energy storage power station capacity demand information;

[0041] A battery quantity information determination module, configured to determine the battery quantity information of the target battery cells based on the maximum operating voltage corresponding to the target battery cells and the energy storage power station capacity demand information;

[0042] An initial total number of H-bridge modules determination module, configured to determine the initial total number of H-bridge modules according to the battery quantity information, the energy storage power station capacity demand information, and the battery cell parameters corresponding to the target battery cells;

[0043] An H-bridge module quantity information and cascaded multilevel energy storage converter parallel quantity determination module, configured to determine the number of H-bridge modules required for a single cascaded multilevel energy storage converter, the total number of H-bridge modules, and the cascaded multilevel energy storage converter parallel quantity according to the preset grid connection parameters and the initial total number of H-bridge modules;

[0044] The main circuit construction module of the battery energy storage power station is used to construct the main circuit of the battery energy storage power station based on the cascaded multilevel topology by using H-bridge modules corresponding to the total number of the H-bridge modules and target battery monomers corresponding to the battery quantity information, and combining the parallel quantity of the cascaded multilevel energy storage converters and the number of the H-bridge modules.

[0045] The present invention also provides an electronic device, including a memory and a processor. When the computer program stored in the memory is executed by the processor, the processor is enabled to execute the steps of implementing the main circuit construction method of the battery energy storage power station as described in any one of the above.

[0046] The present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed, the main circuit construction method of the battery energy storage power station as described in any one of the above is implemented.

[0047] As can be seen from the above technical solutions, the present invention has the following advantages:

[0048] When receiving the energy storage power station capacity demand information, the present invention selects the target battery monomers according to the energy storage power station capacity demand information, and determines the battery quantity information of the target battery monomers based on the maximum operating voltage corresponding to the target battery monomers and the energy storage power station capacity demand information. The total number of initial H-bridge modules is determined according to the battery quantity information, the energy storage power station capacity demand information and the battery monomer parameters corresponding to the target battery monomers. The number of H-bridge modules required for a single cascaded multilevel energy storage converter, the total number of H-bridge modules and the parallel quantity of the cascaded multilevel energy storage converters are determined according to the preset grid connection parameters and the total number of initial H-bridge modules. The main circuit of the battery energy storage power station based on the cascaded multilevel topology is constructed by using H-bridge modules corresponding to the total number of the H-bridge modules and target battery monomers corresponding to the battery quantity information, and combining the parallel quantity of the cascaded multilevel energy storage converters and the number of the H-bridge modules. The technical problem that there is currently a lack of a main circuit construction method for a battery energy storage power station based on the cascaded multilevel topology is solved. The present invention calculates the number of target battery monomers, the number of H-bridge modules, the total number of H-bridge modules and the parallel quantity of the cascaded multilevel energy storage converters required for the energy storage power station subsystem according to information such as the energy storage power station capacity demand and the grid connection parameters, meeting the technical requirements for the construction of the main circuit of the battery energy storage power station based on the cascaded multilevel topology. Description of the Drawings

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0050] Figure 1 This is a schematic diagram of the structure of a battery energy storage converter based on a cascaded multilevel topology in Embodiment 1 of the present invention;

[0051] Figure 2 This is a flowchart of the steps of a method for constructing a main circuit of a battery energy storage power station provided in Embodiment 1 of the present invention;

[0052] Figure 3 This is a flowchart of the steps of a method for constructing a main circuit of a battery energy storage power station provided in Embodiment 2 of the present invention;

[0053] Figure 4 This is a circuit schematic diagram of a battery branch in Embodiment 2 of the present invention;

[0054] Figure 5 This is a wiring diagram of the main circuit of a battery energy storage power station in Embodiment 2 of the present invention;

[0055] Figure 6 This is a structural block diagram of a system for constructing a main circuit of a battery energy storage power station provided in Embodiment 3 of the present invention. Detailed implementation manners

[0056] Embodiments of the present invention provide a method, system, device, and medium for constructing a main circuit of a battery energy storage power station, which are used to solve the technical problem that there is currently a lack of a method for constructing a main circuit of a battery energy storage power station based on a cascaded multilevel topology.

[0057] As Figure 1 shown, the cascaded multilevel converter topology is composed of multiple H-bridge modules. The DC-side voltage levels of each H-bridge module are low and independent of each other, and the AC-sides are connected in series with each other to form an AC multilevel high voltage, which has the advantages of good harmonic characteristics, no need for a step-up transformer, modular structure, easy redundancy, etc., and is very suitable for use as a power conversion link in medium-voltage and large-capacity battery energy storage systems. A plurality of target batteries connected in parallel to the DC side of the H-bridge module are collectively referred to as battery units. The cascaded multilevel battery energy storage system is a three-phase system including multiple H-bridge modules (i.e., H-bridge module A 1 , H-bridge module A 2 ......H-bridge module A N ), a plurality of battery units, a phase A circuit, a phase B circuit, a phase C short circuit, a starting circuit, and a 10 kV power grid. The phase A circuit, the phase B circuit, and the phase C short circuit are connected in parallel and are respectively connected in parallel with the battery units. The output ends of the phase A circuit, the phase B circuit, and the phase C short circuit are respectively connected to the inductor L g , and the output currents are respectively i a , i b and i c , and the output end is connected to the starting circuit and is connected to the 10 kV power grid.

[0058] In order to make the objectives, features, and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the following described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0059] Please refer to Figure 2 , Figure 2 which is a flowchart of the steps of a method for constructing the main circuit of a battery energy storage power station provided in Embodiment 1 of the present invention.

[0060] A method for constructing the main circuit of a battery energy storage power station provided by the present invention includes:

[0061] Step 201: When receiving the energy storage power station capacity demand information, select the target battery cells according to the energy storage power station capacity demand information.

[0062] The energy storage power station capacity demand information includes the total capacity of the energy storage power station, the power of the power station, the voltage information of the preset power semiconductor device, and the number of battery cell interfaces.

[0063] In the embodiment of the present invention, when receiving the energy storage power station capacity demand information, select the target battery cells for constructing the main circuit of the battery energy storage power station according to the total capacity of the energy storage power station and the power of the power station in the energy storage power station capacity demand information.

[0064] Step 202: Based on the maximum operating voltage corresponding to the target battery cells and the energy storage power station capacity demand information, determine the battery cell number information of the target battery cells.

[0065] The battery cell number information includes the number of parallel battery branches corresponding to the target battery cells and the number of series-connected battery cells in a single path. The number of parallel battery branches refers to the number of parallel connections of the battery branches connected to the DC side of a single H-bridge module; the number of series-connected battery cells in a single path refers to the number of series-connected target battery cells on each battery branch.

[0066] In the embodiment of the present invention, calculate the ratio of the total capacity of the energy storage power station to the power of the power station to obtain the discharge duration of the battery energy storage power station, and determine the number of parallel battery branches corresponding to the target battery cells according to the discharge duration. Calculate the ratio of the rated voltage of the preset power semiconductor device, the voltage margin of the preset power semiconductor device, and the maximum operating voltage corresponding to the target battery cells to obtain the initial number of series-connected battery cells in a single path. Combine the number of battery cell interface information, select the smallest multiple value greater than the initial number of series-connected battery cells in a single path, and determine the smallest multiple value as the number of series-connected battery cells in a single path corresponding to the target battery cells.

[0067] Step 203: Determine the total number of initial H-bridge modules according to the battery quantity information, the energy storage power station capacity requirement information, and the battery cell parameters corresponding to the target battery cell.

[0068] The battery cell parameters corresponding to the target battery cell refer to the rated voltage of the battery cell and the capacity of the battery cell. The total number of initial H-bridge modules refers to the ratio of the total capacity of the energy storage power station of the battery energy storage power station to the product of the rated voltage of the battery cell, the capacity of the battery cell, the number of parallel battery branches, and the number of series-connected battery cells of the target battery cell.

[0069] In the embodiment of the present invention, multiply the number of parallel battery branches, the number of series-connected battery cells in a single path, the rated voltage of the battery cell, and the capacity of the battery cell to obtain the rated module capacity corresponding to a single H-bridge module, and take the ratio of the total energy storage capacity of the battery energy storage power station to the rated module capacity corresponding to a single H-bridge module, and determine the total number of initial H-bridge modules as the ratio result.

[0070] Step 204: Determine the number of H-bridge modules required for a single cascaded multi-level energy storage converter, the total number of H-bridge modules, and the number of parallel cascaded multi-level energy storage converters according to the preset grid connection parameters and the total number of initial H-bridge modules.

[0071] The preset grid connection parameters include the effective value of the grid line voltage, the maximum volatility of the grid voltage, the maximum unbalance degree of the grid voltage, the per-unit value of the AC filter inductor, the manufacturing error of the AC filter inductor, the maximum modulation ratio of the inverter, the maximum amplitude of the second-order ripple of the DC capacitor voltage of the H-bridge module, the minimum operating voltage of the battery unit on the DC side of the H-bridge module, and the module redundancy.

[0072] The total number of H-bridge modules refers to the total number of H-bridge modules included in the finally determined energy storage power station. The number of parallel cascaded multi-level energy storage converters refers to the number of parallel cascaded multi-level energy storage converters in the main circuit of the battery energy storage power station.

[0073] In the embodiment of the present invention, substitute the preset grid connection parameters into the formula for calculating the number of single-phase H-bridge modules of a single cascaded multi-level energy storage converter to determine the number of H-bridge modules required for a single cascaded multi-level energy storage converter, take the ratio of the total number of initial H-bridge modules to the number of H-bridge modules required for a single cascaded multi-level energy storage converter to obtain a module ratio, perform a rounding operation on the module ratio, and combine the module redundancy to obtain the downward-rounded number of parallel cascaded multi-level energy storage converters and the upward-rounded number of parallel cascaded multi-level energy storage converters. Compare the actual total number of H-bridge modules required under the downward-rounded number of parallel cascaded multi-level energy storage converters with the actual total number of H-bridge modules required under the upward-rounded number of parallel cascaded multi-level energy storage converters, and determine the total number of H-bridge modules and the number of parallel cascaded multi-level energy storage converters according to the comparison result.

[0074] Step 205: Using H-bridge modules with a quantity corresponding to the total number of H-bridge modules and target battery cells with a quantity corresponding to the battery quantity information, and combining the parallel quantity of cascaded multilevel energy storage converters and the quantity of H-bridge modules, construct the main circuit of the battery energy storage power station based on the cascaded multilevel topology.

[0075] The main circuit of the battery energy storage power station refers to connecting the corresponding quantity of H-bridge modules, target batteries, and preset power semiconductor devices according to the energy storage power station capacity demand information to construct the main circuit corresponding to the battery energy storage power station.

[0076] In the embodiment of the present invention, target battery cells corresponding to the quantity of single-path series-connected battery cells are used to construct battery branches, and H-bridge modules corresponding to the total number of H-bridge modules are selected. The battery branches are respectively connected to the DC sides of each H-bridge module according to the quantity of parallel battery branches, and combined with the quantity of single-phase H-bridge modules of a single cascaded multilevel energy storage converter to obtain a single cascaded multilevel energy storage converter. Then, each cascaded multilevel energy storage converter is paralleled according to the parallel quantity of single cascaded multilevel energy storage converters and connected to the bus corresponding to the battery energy storage power station to obtain the main circuit of the battery energy storage power station.

[0077] In the embodiment of the present invention, when receiving the energy storage power station capacity demand information, the target battery cells are selected according to the energy storage power station capacity demand information, and based on the maximum operating voltage corresponding to the target battery cells and the energy storage power station capacity demand information, the battery quantity information of the target battery cells is determined. With the battery quantity information, the energy storage power station capacity demand information, and the battery cell parameters corresponding to the target battery cells, the total number of initial H-bridge modules is determined. With the preset grid connection parameters and the total number of initial H-bridge modules, the quantity of H-bridge modules required for a single cascaded multilevel energy storage converter, the total number of H-bridge modules, and the parallel quantity of cascaded multilevel energy storage converters are determined. Using H-bridge modules with a quantity corresponding to the total number of H-bridge modules and target battery cells with a quantity corresponding to the battery quantity information, and combining the parallel quantity of cascaded multilevel energy storage converters and the quantity of H-bridge modules, construct the main circuit of the battery energy storage power station based on the cascaded multilevel topology. This solves the technical problem of the lack of a main circuit construction method for a battery energy storage power station based on the cascaded multilevel topology. The present invention calculates the required quantity of target battery cells, the quantity of H-bridge modules, the total number of H-bridge modules, and the parallel quantity of cascaded multilevel energy storage converters for the energy storage power station subsystem according to information such as the energy storage power station capacity demand and grid connection parameters, meeting the technical requirements for the construction of the main circuit of the battery energy storage power station based on the cascaded multilevel topology.

[0078] Please refer to Figure 3 , Figure 3 which is the step flowchart of a method for constructing the main circuit of a battery energy storage power station provided in Embodiment 2 of the present invention.

[0079] Step 301: When receiving the energy storage power station capacity demand information, select the target battery cell according to the energy storage power station capacity demand information.

[0080] In an embodiment of the present invention, when receiving the total capacity of the energy storage power station, the power of the power station, the voltage information of the preset power semiconductor device, and the number of battery cell interfaces, select the target battery cell for constructing the main circuit of the battery energy storage power station according to the total capacity of the energy storage power station and the power of the power station.

[0081] Step 302: Based on the maximum operating voltage corresponding to the target battery cell and the energy storage power station capacity demand information, determine the number of battery cells of the target battery cell.

[0082] Optionally, step 302 may include the following sub-steps S11 - S13:

[0083] S11: Calculate the ratio of the total capacity of the energy storage power station to the power of the power station to obtain the discharge duration of the battery energy storage power station.

[0084] In an embodiment of the present invention, take the ratio of the total capacity of the energy storage power station and the power of the power station in the energy storage power station capacity demand information, and determine the ratio result as the discharge duration of the battery energy storage power station.

[0085] S12: Determine the number of parallel battery branches corresponding to the target battery cell according to the discharge duration.

[0086] Further, step S12 may include the following sub-steps S121 - S122:

[0087] S121: Use the discharge duration as a keyword to match the corresponding target application scenario from the preset scenario information table.

[0088] The preset scenario information table refers to a table made by dividing multiple charging and discharging application scenarios corresponding to multiple power stations and the corresponding battery branches according to different discharge durations of the battery energy storage power station, with the number of parallel battery branches in general being within 1 - 4. Common charging and discharging application scenarios include small current and long-time charging and discharging application scenarios, large current and short-time charging and discharging application scenarios, etc.

[0089] In an embodiment of the present invention, calculate the ratio of the total capacity of the energy storage power station to the power of the power station to obtain the discharge duration. Use the discharge duration as a keyword to find the charging and discharging application scenario corresponding to the discharge duration from the preset scenario information table, and set the charging and discharging scenario as the target application scenario.

[0090] S122: Determine the number of parallel battery branches corresponding to the target application scenario as the number of parallel battery branches corresponding to the target battery cell.

[0091] In an embodiment of the present invention, when determining a target application scenario, the number of parallel battery branches corresponding to the target application scenario is selected from a preset information table, and the number of parallel battery branches is determined as the number of parallel battery branches corresponding to the target battery cell.

[0092] S13. Determine the number of series-connected battery cells in a single path corresponding to the target battery cell according to the preset power semiconductor device voltage information, the maximum operating voltage corresponding to the target battery cell, and the battery cell interface quantity information.

[0093] Further, the preset power semiconductor device voltage information includes the rated voltage of the preset power semiconductor device and the voltage margin of the preset power semiconductor device. Step S13 may include the following sub-steps S131 - S133:

[0094] S131. Calculate the ratio of the rated voltage of the preset power semiconductor device, the voltage margin of the preset power semiconductor device, and the maximum operating voltage corresponding to the target battery cell to obtain the initial number of series-connected battery cells in a single path.

[0095] The rated voltage of the preset power semiconductor device refers to the rated operating voltage of the intended power semiconductor device. The voltage margin of the preset power semiconductor device refers to the maximum voltage margin of the intended power semiconductor device in design. For example, the voltage margin of a switching device in a general converter is designed to be 1.7 - 2, so the voltage margin of the preset power semiconductor device can be taken as 2. The maximum operating voltage corresponding to the target battery cell refers to the maximum voltage value that can be reached within the voltage operating range of the target battery cell.

[0096] In an embodiment of the present invention, the maximum operating voltage that can be reached within the voltage operating range of the target battery cell is selected, and the ratio of the rated voltage of the preset power semiconductor device, the voltage margin of the preset power semiconductor device, and the maximum operating voltage corresponding to the target battery cell is calculated to obtain the initial number of series-connected battery cells in a single path.

[0097] S132. Select the smallest multiple value greater than the initial number of series-connected battery cells in a single path from the multiple values corresponding to the battery cell interface quantity information.

[0098] The battery cell interface quantity information refers to multiple value sets set according to the battery cell interface quantity information in common battery management system (BMS) products. The battery cell interface quantity is generally 8 or 16, and multiple value sets corresponding to 8 and 16 are generated.

[0099] In an embodiment of the present invention, the smallest multiple value greater than the initial number of series-connected battery cells in a single path calculated from the rated voltage of the preset power semiconductor device, the voltage margin of the preset power semiconductor device, and the maximum operating voltage corresponding to the target battery cell is selected from the multiple values corresponding to the battery cell interface quantity information.

[0100] S133. Determine the number of single - series battery cells corresponding to the target battery cell as the minimum multiple value.

[0101] In an embodiment of the present invention, after selecting the minimum multiple value greater than the initial number of single - series battery cells from the multiple multiple values corresponding to the battery cell interface quantity information, the minimum multiple value is set as the number of single - series battery cells corresponding to the target battery.

[0102] Step 303. Calculate the battery quantity information, the rated voltage of the battery cell, and the capacity of the battery cell to obtain the rated module capacity corresponding to a single H - bridge module.

[0103] In an embodiment of the present invention, the battery quantity information includes the number of parallel battery branches corresponding to the target battery cell and the number of single - series battery cells. Calculate the product of the rated voltage of the battery cell, the capacity of the battery cell, the number of parallel battery branches, and the number of single - series battery cells to obtain the rated module capacity corresponding to a single H - bridge module.

[0104] Step 304. Calculate the ratio of the total energy storage power station capacity corresponding to the energy storage power station capacity requirement information to the rated module capacity to determine the initial total number of H - bridge modules.

[0105] In an embodiment of the present invention, calculate the ratio of the total energy storage power station capacity in the power station capacity requirement information to the rated module capacity corresponding to a single H - bridge module to obtain the total number of at least required H - bridge modules for the battery energy storage power station, that is, the initial total number of H - bridge modules.

[0106] Step 305. Determine the number of H - bridge modules required for a single cascaded multilevel energy storage converter, the total number of H - bridge modules, and the number of parallel cascaded multilevel energy storage converters according to the preset grid connection parameters and the initial total number of H - bridge modules.

[0107] Optionally, step 305 may include the following sub - steps S21 - S28:

[0108] S21. Substitute the preset grid connection parameters into the preset single - phase H - bridge module quantity calculation formula for a single cascaded multilevel energy storage converter to determine the number of H - bridge modules required for a single cascaded multilevel energy storage converter.

[0109] The preset single - phase H - bridge module quantity calculation formula for a single cascaded multilevel energy storage converter is:

[0110]

[0111] where, U sl$U$ is the effective value of the grid-connected line voltage, $\lambda$ is the maximum volatility of the grid voltage, $\delta$ is the maximum unbalance degree of the grid voltage, $\chi$ is the per-unit value of the AC filter inductor, $\varepsilon$ is the manufacturing error of the AC filter inductor, $M$ is the maximum modulation ratio of the inverter, $\alpha$ is the maximum amplitude of the second-order ripple of the DC capacitor voltage of the sub-module. bat_min $U_{ bat_min}$ is the minimum operating voltage of the battery unit on the DC side of the H-bridge module, and $\gamma$ is the module redundancy.

[0112] In the embodiment of the present invention, by substituting the preset grid-connected parameters of the power grid into the calculation formula of the number of single-phase H-bridge modules of the preset single-stage cascaded multilevel energy storage converter, the number of single-phase H-bridge modules is calculated. Since the main circuit of the battery energy storage power station uses a three-phase system, the number of single-phase H-bridge modules is multiplied by three to obtain the number of H-bridge modules required for a single-stage cascaded multilevel energy storage converter, and the number of redundant modules in the number of H-bridge modules is calculated through the module redundancy.

[0113] S22. Calculate the ratio of the total number of initial H-bridge modules to the number of H-bridge modules to obtain the module ratio.

[0114] The module ratio refers to the initial parallel number corresponding to the cascaded multilevel energy storage converter of the energy storage power station calculated by taking the ratio of the total number of initial H-bridge modules to the number of H-bridge modules required for a single-stage cascaded multilevel energy storage converter.

[0115] In the embodiment of the present invention, the total capacity of the energy storage power station and the total number of initial H-bridge modules calculated from the rated module capacity corresponding to a single H-bridge module are used to calculate the ratio of the total number of initial H-bridge modules to the number of H-bridge modules required for a single-stage cascaded multilevel energy storage converter, and the initial parallel number corresponding to the cascaded multilevel energy storage converter of the energy storage power station is determined.

[0116] S23. Perform a rounding operation on the module ratio to obtain the downward-rounded parallel number of cascaded multilevel energy storage converters and the upward-rounded parallel number of cascaded multilevel energy storage converters.

[0117] In the embodiment of the present invention, since the ratio of the total number of initial H-bridge modules to the number of H-bridge modules required for a single-stage cascaded multilevel energy storage converter usually has a decimal, it is necessary to round the module ratio to obtain the downward-rounded parallel number of cascaded multilevel energy storage converters and the upward-rounded parallel number of cascaded multilevel energy storage converters.

[0118] S24. Calculate the total number of actual H-bridge modules required for the downward-rounded parallel number of cascaded multilevel energy storage converters to obtain the corresponding first initial number.

[0119] The first initial number refers to the total number of actual H-bridge modules required for all cascaded multilevel energy storage converters when the parallel number of cascaded multilevel energy storage converters is downward-rounded.

[0120] In the embodiment of the present invention, when rounding down the number of cascaded multilevel energy storage converters in parallel, according to the obtained number of parallel connections, the number of H-bridge modules required for a single cascaded multilevel energy storage converter is correspondingly adjusted to obtain the corresponding first initial number.

[0121] S25. Calculate the total actual number of H-bridge modules required for the cascaded multilevel energy storage converter when rounding up the number of parallel connections, to obtain the corresponding second initial number.

[0122] The second initial number refers to the total actual number of H-bridge modules required for all cascaded multilevel energy storage converters when the number of parallel connections is the rounded-up number of parallel connections of the cascaded multilevel energy storage converter.

[0123] In the embodiment of the present invention, when rounding up the number of parallel connections of the cascaded multilevel energy storage converter, according to the obtained number of parallel connections, the number of H-bridge modules required for a single cascaded multilevel energy storage converter is correspondingly adjusted to obtain the corresponding second initial number.

[0124] S26. Compare the first initial number and the second initial number.

[0125] In the embodiment of the present invention, since as the number of H-bridge modules increases, the number of target battery cells increases sharply, and the amount of data that the energy storage power station controller needs to process doubles, therefore, it is necessary to compare the first initial number and the second initial number and select the smaller value of the two.

[0126] S27. If the first initial number is greater than the second initial number, then use the second initial number as the total number of H-bridge modules, and use the rounded-up number of parallel connections of the cascaded multilevel energy storage converter as the number of parallel connections of the cascaded multilevel energy storage converter.

[0127] In the embodiment of the present invention, the first initial number is compared with the second initial number. When the first initial number is greater than the second initial number, use the second initial number as the total number of H-bridge modules, and use the rounded-up number of parallel connections of the cascaded multilevel energy storage converter as the number of parallel connections of the cascaded multilevel energy storage converter.

[0128] S28. If the first initial number is less than the second initial number, then use the first initial number as the total number of H-bridge modules, and use the rounded-down number of parallel connections of the cascaded multilevel energy storage converter as the number of parallel connections of the cascaded multilevel energy storage converter.

[0129] In the embodiment of the present invention, the first initial number is compared with the second initial number. When the first initial number is less than the second initial number, use the first initial number as the total number of H-bridge modules, and use the rounded-down number of parallel connections of the cascaded multilevel energy storage converter as the number of parallel connections of the cascaded multilevel energy storage converter.

[0130] Step 306: Use H-bridge modules with a quantity corresponding to the total number of H-bridge modules and target battery cells with a quantity corresponding to the battery quantity information, and combine the parallel quantity of cascaded multilevel energy storage converters and the quantity of H-bridge modules to construct the main circuit of the battery energy storage power station based on the cascaded multilevel topology.

[0131] Optionally, step 306 may include the following sub-steps S31 - S34:

[0132] S31: Use target battery cells corresponding to the quantity of single-path series-connected battery cells to construct a battery branch.

[0133] In the embodiment of the present invention, the quantity of single-path series-connected battery cells is equal to the smallest multiple value greater than the initial single-path battery quantity among multiple multiple values corresponding to the battery cell interface quantity information, and target battery cells corresponding to the quantity of single-path series-connected battery cells are selected to construct a battery branch.

[0134] S32: Select H-bridge modules corresponding to the total number of H-bridge modules.

[0135] In the embodiment of the present invention, the total number of H-bridge modules is determined by the comparison result of the first initial quantity and the second initial quantity, and corresponding H-bridge modules are selected according to the total number of H-bridge modules.

[0136] S33: Connect the battery branches to the DC sides of each H-bridge module respectively according to the quantity of parallel battery branches, and combine with the quantity of H-bridge modules to obtain a single cascaded multilevel energy storage converter.

[0137] In the embodiment of the present invention, multiple battery branches constructed from target battery cells according to the quantity of single-path series-connected battery cells are connected to the DC sides of each H-bridge module respectively according to the quantity of parallel battery branches, and H-bridge modules corresponding to the quantity of single-phase H-bridge modules of a single cascaded multilevel energy storage converter are connected, thereby constructing a single cascaded multilevel energy storage converter.

[0138] S34: Parallel each cascaded multilevel energy storage converter according to the quantity of parallel branches of the cascaded multilevel energy storage converter and connect it to the corresponding bus of the battery energy storage power station to obtain the main circuit of the battery energy storage power station.

[0139] In the embodiment of the present invention, the constructed cascaded multilevel energy storage converters of the energy storage power station are paralleled according to the parallel quantity of the cascaded multilevel energy storage converters and connected to the corresponding bus of the battery energy storage power station, thereby constructing the main circuit of the battery energy storage power station. Based on the power and capacity of the energy storage power station subsystem, the parameter calculation of AC filter inductance, DC filter inductance, DC capacitor, etc. in the main circuit of the battery energy storage power station and the selection of power semiconductor devices are further improved.

[0140] For example: The selected target battery is a lithium iron phosphate battery with 3.2V / 280Ah. A battery energy storage power station with 40MW / 300MWh is designed. The voltage level of the bus connected is 10kV. The cascaded multilevel converter is star-connected and consists of multiple H-bridge modules. The main circuit of the battery energy storage power station is composed of multiple cascaded multilevel energy storage converters connected in parallel. The specific design process of the main circuit of the battery energy storage power station is as follows:

[0141] Step 1: The charge and discharge duration of the battery energy storage power station is 300MWh / 40MW = 5h, which belongs to the target application scenario with a small charge and discharge current and a long time. Combining with the preset scenario information table, it is determined that the number of parallel battery branches connected in parallel on the DC side of the H-bridge module is 2.

[0142] Step 2: The cascaded multilevel converter uses the preset power semiconductor device as the IGBT switching device. The rated voltage of the selected IGBT is 1700V. The voltage margin of the preset power semiconductor device is 1.7 - 2, and the preset IGBT voltage margin is 2. The operating range of the target battery cell is 2.8 - 3.6V, and the maximum operating voltage of the target battery cell is 3.6V. Then the initial number of series-connected battery cells in a single path is 1700 / 2 / 3.6 = 236.1. The number of battery cell interfaces in common battery management system (BMS) products is generally 8 or 16. Select the smallest multiple value greater than the initial number of single-path batteries from the multiple values corresponding to 8 or 16 in the battery cell interface number information as the number of single-path batteries corresponding to the target battery, that is, the number of single-path batteries is designed to be 240. And because the capacity of the target battery cell is large, the target battery cells are only connected in series and not in parallel. The specific connection relationship is as Figure 4 shown. 1P240S means that the number of series-connected battery cells in a single path is designed to be 240, and the number of parallel battery branches is 2. 215kWh means that the battery capacity is 240 * 3.2V * 280Ah = 215kWh, and the battery branch is connected to the DC side of the H-bridge module.

[0143] Step 3: Based on the rated voltage of 3.2V, the capacity of 280Ah of the target battery cell, the number of parallel battery branches 2 obtained in Step 1, and the number of series-connected battery cells in a single path 240 calculated in Step 2, the rated module capacity corresponding to a single H-bridge module is calculated as 280Ah * 3.2V * 240 * 2 = 430kWh. And the total energy storage capacity of the designed battery energy storage power station is 300MWh. Therefore, the total number of H-bridge modules required for the battery energy storage power station is at least 300MWh / 0.43kWh = 466, that is, the initial total number of H-bridge modules is 466.

[0144] Step 4: The preset grid connection parameters are respectively λ = 30%, δ = 2%, ε = 3%, χ = 15%, M = 98%, α = 10%, γ = 10%, Ubat_min = 2.8V * 240 = 672V, U sl = 10kV. Substitute the preset grid connection parameters into the calculation formula for the number of single-phase H-bridge modules of a preset single cascaded multilevel energy storage converter, and calculate to get N = 30.9. Then, round up the number of single-phase sub-modules N of a single cascaded multilevel energy storage power station subsystem with redundancy to 21, where the number of redundant modules is 2. Since the main circuit of the battery energy storage power station uses a three-phase system, multiply the number of single-phase H-bridge modules by three to get the number of H-bridge modules required for a single cascaded multilevel energy storage converter as 3 * 21.

[0145] Step 5: Take the ratio of the total number of initial H-bridge modules 466 calculated in Step 3 to the number of H-bridge modules required for a single cascaded multilevel energy storage converter 3 * 21 calculated in Step 4. The result is 7.40. Perform a rounding operation on this module ratio. By adjusting the number of H-bridge modules of a single cascaded multilevel energy storage converter, the downward-rounded number of parallel cascaded multilevel energy storage converters, the upward-rounded number of parallel cascaded multilevel energy storage converters, and the corresponding total number of H-bridge modules can be obtained, and the following two main circuit schemes for the battery energy storage power station can be obtained:

[0146] Scheme 1 (upward rounding): 8 cascaded multilevel energy storage converters are connected in parallel. Each cascaded multilevel energy storage converter has 3 * 21 H-bridge modules (2 redundant), and the capacity of a single H-bridge module is 0.43 kWh. Then, the actual capacity of the whole station is overconfigured by 8% compared with the rated capacity;

[0147] Scheme 2 (downward rounding): 7 cascaded multilevel energy storage converters are connected in parallel. Each cascaded multilevel energy storage converter has 3 * 23 H-bridge modules (4 redundant), and the capacity of a single H-bridge module is 0.43 kWh. Then, the actual capacity of the whole station is overconfigured by 4% compared with the rated capacity.

[0148] The battery overconfiguration amounts of the two schemes are not very different. However, as the number of H-bridge modules in the cascaded multilevel energy storage converter increases, the number of target battery monomers increases sharply, and the amount of data that the cascaded multilevel energy storage converter controller needs to process increases exponentially. Therefore, choose Scheme 1, that is, a total of 8 cascaded multilevel energy storage converters are connected in parallel in the whole station, where the number of series-connected battery monomers in a single path is 240, the number of parallel battery branches is 2, and the number of H-bridge modules of a single cascaded multilevel energy storage converter is 3 * 21. Construct a cascaded multilevel converter using H-bridge modules corresponding to the number of H-bridge modules according to Scheme 1, connect the battery branches to the DC sides of each H-bridge module respectively according to the number of parallel battery branches to obtain a single cascaded multilevel energy storage converter. The capacity of each single cascaded multilevel energy storage converter is 5 MW / 27.1 MWh. Connect each cascaded multilevel energy storage converter in parallel according to the number of parallel cascaded multilevel energy storage converters and connect it to the 10 kV busbar to obtain the main circuit of the battery energy storage power station, asFigure 5 as shown

[0149] Step 6: According to the power and capacity of a single cascaded multilevel energy storage converter calculated in Step 5, combined with the preset converter design scheme, calculate that the value of the AC filter inductor is 10 mH, the value of the DC capacitor is 4.7 mF, the value of the DC filter inductor is 3 mH, and the IGBT of the model 1700V / 600A can be selected.

[0150] In the embodiment of the present invention, when receiving the total capacity of the energy storage power station, the power of the power station, the voltage information of the preset power semiconductor device, and the number information of the battery cell interfaces, select the target battery cell for constructing the main circuit of the battery energy storage power station according to the total capacity of the energy storage power station and the power of the power station. Calculate the ratio of the total capacity of the energy storage power station to the power of the power station to obtain the discharge duration of the battery energy storage power station. Use the discharge duration as the keyword to match the corresponding target application scenario from the preset scenario information table, so as to determine the number of parallel battery branches corresponding to the target application scenario as the number of parallel battery branches corresponding to the target battery. Calculate the ratio of the rated voltage of the preset power semiconductor device, the voltage margin of the preset power semiconductor device, and the maximum operating voltage corresponding to the target battery cell to obtain the initial number of series-connected battery cells in a single path. Select the smallest multiple value greater than the initial number of series-connected battery cells in a single path from the multiple values corresponding to the number information of the battery cell interfaces, and select the smallest multiple value greater than the initial number of series-connected battery cells in a single path from the multiple values corresponding to the number information of the battery cell interfaces.

[0151] Calculate the number of battery information, the rated voltage of a single battery cell, and the capacity of a single battery cell to obtain the rated module capacity corresponding to a single H-bridge module. Calculate the ratio of the total capacity of the energy storage power station corresponding to the energy storage power station capacity demand information to the rated module capacity to determine the total number of initial H-bridge modules. Substitute the preset grid connection parameters into the formula for a single-phase H-bridge module of a preset cascaded multilevel energy storage converter to determine the number of H-bridge modules required for a single cascaded multilevel energy storage converter. Calculate the ratio of the total number of initial H-bridge modules to the number of H-bridge modules required for a single cascaded multilevel energy storage converter to obtain a module ratio. Perform a rounding operation on the module ratio to obtain the downward-rounded number of parallel cascaded multilevel energy storage converters and the upward-rounded number of parallel cascaded multilevel energy storage converters. Calculate the total actual number of H-bridge modules required for the downward-rounded number of parallel cascaded multilevel energy storage converters to obtain the corresponding first initial number. Calculate the total actual number of H-bridge modules required for the upward-rounded number of parallel cascaded multilevel energy storage converters to obtain the corresponding second initial number. Compare the first initial number and the second initial number, and determine the total number of H-bridge modules and the number of parallel cascaded multilevel energy storage converters based on the comparison result. Use the target battery cells corresponding to the number of series-connected battery cells in a single path to construct a battery branch. Select the H-bridge modules corresponding to the total number of H-bridge modules. Connect the battery branch to the DC side of each H-bridge module according to the number of parallel battery branches to obtain a cascaded multilevel energy storage converter. Parallelize each cascaded multilevel energy storage converter according to the number of parallel paths of the cascaded multilevel energy storage converter and connect it to the bus corresponding to the battery energy storage power station to obtain the main circuit of the battery energy storage power station. It realizes calculating the required number of target battery cells, the number of H-bridge modules, the total number of H-bridge modules, and the number of parallel cascaded multilevel energy storage converters based on information such as the energy storage power station capacity demand and grid connection parameters, meeting the technical requirements for constructing the main circuit of a battery energy storage power station based on a cascaded multilevel topology.

[0152] Please refer to Figure 6 , Figure 6 which is the structural block diagram of a system for constructing the main circuit of a battery energy storage power station provided in Embodiment 3 of the present invention.

[0153] A system for constructing the main circuit of a battery energy storage power station provided in an embodiment of the present invention includes:

[0154] A target battery selection module 601, configured to select target battery cells according to the energy storage power station capacity demand information when receiving the energy storage power station capacity demand information.

[0155] A battery quantity information determination module 602, configured to determine the battery quantity information of the target battery cells based on the maximum operating voltage corresponding to the target battery cells and the energy storage power station capacity demand information.

[0156] The initial H-bridge module total number determination module 603 is configured to determine the total number of initial H-bridge modules according to the battery quantity information, the energy storage power station capacity requirement information, and the battery cell parameters corresponding to the target battery cell.

[0157] The H-bridge module quantity information and cascaded multilevel energy storage converter parallel quantity determination module 604 is configured to determine the number of H-bridge modules required for a single cascaded multilevel energy storage converter, the total number of H-bridge modules, and the cascaded multilevel energy storage converter parallel quantity according to the preset grid connection parameters and the total number of initial H-bridge modules.

[0158] The battery energy storage power station main circuit construction module 605 is configured to construct the main circuit of the battery energy storage power station based on the cascaded multilevel topology by using H-bridge modules corresponding to the total number of H-bridge modules and target battery cells corresponding to the battery quantity information, in combination with the cascaded multilevel energy storage converter parallel quantity and the number of H-bridge modules.

[0159] Optionally, the energy storage power station capacity requirement information includes the total capacity of the energy storage power station, the power of the power station, the preset power semiconductor device voltage information, and the battery cell interface quantity information. The battery quantity information determination module 602 includes:

[0160] The discharge duration calculation module is configured to calculate the ratio of the total capacity of the energy storage power station to the power of the power station to obtain the discharge duration of the battery energy storage power station.

[0161] The parallel battery branch quantity determination module is configured to determine the number of parallel battery branches corresponding to the target battery cell according to the discharge duration.

[0162] Further, the parallel battery branch quantity determination module may also perform the following steps:

[0163] Use the discharge duration as a keyword to match the corresponding target application scenario from the preset scenario information table;

[0164] Determine the number of parallel battery branches corresponding to the target application scenario as the number of parallel battery branches corresponding to the target battery cell.

[0165] The single-path series battery cell quantity determination module is configured to determine the number of single-path series battery cells corresponding to the target battery cell according to the preset power semiconductor device voltage information, the maximum operating voltage corresponding to the target battery cell, and the battery cell interface quantity information.

[0166] Further, the preset power semiconductor device voltage information includes the rated voltage of the preset power semiconductor device and the voltage margin of the preset power semiconductor device. The single-path series battery cell quantity determination module may also perform the following steps:

[0167] Calculate the ratio of the rated voltage of the preset power semiconductor device, the voltage margin of the preset power semiconductor device, and the maximum operating voltage corresponding to the target battery cell to obtain the initial number of series-connected battery cells in a single path;

[0168] Select the smallest multiple value greater than the initial number of series-connected battery cells in a single path from the multiple values corresponding to the battery cell interface quantity information;

[0169] Determine the number of series-connected battery cells in a single path corresponding to the target battery cell as the smallest multiple value.

[0170] Optionally, the battery cell parameters include the rated voltage of the battery cell and the capacity of the battery cell. The initial total number of H-bridge module determination module 603 includes:

[0171] A rated module capacity obtaining module, configured to calculate the quantity information of the battery cells, the rated voltage of the battery cell, and the capacity of the battery cell to obtain the rated module capacity corresponding to a single H-bridge module.

[0172] An initial total number of H-bridge module determination sub-module, configured to calculate the ratio of the total capacity of the energy storage power station corresponding to the energy storage power station capacity demand information to the rated module capacity, and determine the initial total number of H-bridge modules.

[0173] Optionally, the H-bridge module quantity information and the parallel connection quantity determination module 604 of the cascaded multilevel energy storage converter include:

[0174] A cascaded multilevel energy storage converter H-bridge module quantity determination module, configured to substitute the preset grid connection parameters into the single-phase H-bridge module quantity calculation formula of the preset single cascaded multilevel energy storage converter to determine the number of H-bridge modules required for a single cascaded multilevel energy storage converter.

[0175] A module ratio obtaining module, configured to calculate the ratio of the initial total number of H-bridge modules to the number of H-bridge modules to obtain a module ratio.

[0176] An upward and downward rounding parallel connection quantity obtaining module, configured to perform a rounding operation on the module ratio to obtain a downward rounded cascaded multilevel energy storage converter parallel connection quantity and an upward rounded cascaded multilevel energy storage converter parallel connection quantity.

[0177] A first initial quantity calculation module, configured to calculate the actual total number of H-bridge modules required under the downward rounded cascaded multilevel energy storage converter parallel connection quantity to obtain a corresponding first initial quantity.

[0178] A second initial quantity calculation module, configured to calculate the actual total number of H-bridge modules required under the upward rounded cascaded multilevel energy storage converter parallel connection quantity to obtain a second initial quantity.

[0179] A first initial quantity and second initial quantity comparison module, configured to compare the first initial quantity and the second initial quantity.

[0180] The first comparison result module is configured to, if the first initial quantity is greater than the second initial quantity, use the second initial quantity as the total number of H-bridge modules and use the ceiling of the cascaded multi-level energy storage converter parallel connection quantity as the cascaded multi-level energy storage converter parallel connection quantity.

[0181] The second comparison result module is configured to, if the first initial quantity is less than the second initial quantity, use the first initial quantity as the total number of H-bridge modules and use the floor of the cascaded multi-level energy storage converter parallel connection quantity as the cascaded multi-level energy storage converter parallel connection quantity.

[0182] Optionally, the main circuit construction module 605 of the battery energy storage power station includes:

[0183] The battery branch construction module is configured to construct a battery branch by using target battery monomers corresponding to the number of single-path series-connected battery monomers.

[0184] The H-bridge module selection module is configured to select H-bridge modules corresponding to the total number of H-bridge modules.

[0185] The cascaded multi-level energy storage converter obtaining module is configured to connect the battery branches to the DC sides of the respective H-bridge modules according to the number of parallel battery branches, and combine with the number of H-bridge modules to obtain a single cascaded multi-level energy storage converter.

[0186] The main circuit construction sub-module of the battery energy storage power station is configured to parallel the respective cascaded multi-level energy storage converters according to the cascaded multi-level energy storage converter parallel connection quantity and connect to the bus corresponding to the battery energy storage power station to obtain the main circuit of the battery energy storage power station.

[0187] An embodiment of the present invention further provides an electronic device, which includes a memory and a processor, and a computer program is stored in the memory; when the computer program is executed by the processor, the processor is caused to execute the battery energy storage power station main circuit construction method according to any one of the above embodiments.

[0188] The memory can be an electronic memory such as a flash memory, EEPROM (Electrically Erasable Programmable Read-Only Memory), EPROM, hard disk, or ROM. The memory has a storage space for program codes for executing any of the method steps in the above methods. For example, the storage space for program codes can include respective program codes for implementing various steps in the above methods. These program codes can be read from or written into one or more computer program products. These computer program products include program code carriers such as hard disks, compact discs (CDs), memory cards, or floppy disks. The program codes can be compressed in a suitable form, for example. When these codes are run by a computing processing device, the computing processing device is caused to execute each of the steps in the battery energy storage power station main circuit construction method described above.

[0189] An embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the battery energy storage power station main circuit construction method as in any of the above embodiments.

[0190] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0191] In several embodiments provided in the present application, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed mutual coupling, direct coupling, or communication connection can be through some interfaces. The indirect coupling or communication connection of devices or units can be in an electrical, mechanical, or other form.

[0192] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place, or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0193] In addition, in each embodiment of the present invention, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0194] When the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this 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 for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0195] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of various embodiments of the present invention.

Claims

1. A method for constructing the main circuit of a battery energy storage power station, characterized in that, it includes: When receiving the energy storage power station capacity demand information, select the target battery cell according to the energy storage power station capacity demand information; Based on the maximum working voltage corresponding to the target battery cell and the energy storage power station capacity demand information, determine the battery quantity information of the target battery cell; According to the battery quantity information, the energy storage power station capacity demand information, and the battery cell parameters corresponding to the target battery cell, determine the total number of initial H-bridge modules; According to the preset grid connection parameters and the total number of initial H-bridge modules, determine the number of H-bridge modules required for a single cascaded multilevel energy storage converter, the total number of H-bridge modules, and the number of parallel cascaded multilevel energy storage converters; Adopt H-bridge modules with a quantity corresponding to the total number of H-bridge modules and the target battery cells with a quantity corresponding to the battery quantity information, and combine the number of parallel cascaded multilevel energy storage converters and the number of H-bridge modules to construct the main circuit of the battery energy storage power station based on the cascaded multilevel topology; The step of determining the number of H-bridge modules required for a single cascaded multilevel energy storage converter, the total number of H-bridge modules, and the number of parallel cascaded multilevel energy storage converters according to the preset grid connection parameters and the total number of initial H-bridge modules includes: Substitute the preset grid connection parameters into the single-phase H-bridge module quantity calculation formula of the preset single cascaded multilevel energy storage converter to determine the number of H-bridge modules required for a single cascaded multilevel energy storage converter; Calculate the ratio of the total number of initial H-bridge modules to the number of H-bridge modules to obtain the module ratio; Perform a rounding-down operation on the module ratio to obtain the rounded-down number of parallel cascaded multilevel energy storage converters and the rounded-up number of parallel cascaded multilevel energy storage converters; Calculate the total actual number of H-bridge modules required under the rounded-down number of parallel cascaded multilevel energy storage converters to obtain the corresponding first initial quantity; Calculate the total actual number of H-bridge modules required under the rounded-up number of parallel cascaded multilevel energy storage converters to obtain the second initial quantity; Compare the first initial quantity with the second initial quantity; If the first initial quantity is greater than the second initial quantity, then use the second initial quantity as the total number of H-bridge modules and the rounded-up number of parallel cascaded multilevel energy storage converters as the number of parallel cascaded multilevel energy storage converters; If the first initial quantity is less than the second initial quantity, then use the first initial quantity as the total number of H-bridge modules and the rounded-down number of parallel cascaded multilevel energy storage converters as the number of parallel cascaded multilevel energy storage converters.

2. The method for constructing the main circuit of a battery energy storage power station according to claim 1, characterized in that, the energy storage power station capacity demand information includes the total capacity of the energy storage power station, the power of the power station, the voltage information of the preset power semiconductor device, and the number of battery cell interfaces; the step of determining the battery quantity information of the target battery cell based on the maximum working voltage corresponding to the target battery cell and the energy storage power station capacity demand information includes: Calculate the ratio of the total capacity of the energy storage power station to the power of the power station to obtain the discharge duration of the battery energy storage power station; Determine the number of parallel battery branches corresponding to the target battery cell according to the discharge duration; Determine the number of series-connected battery cells in a single path corresponding to the target battery cell according to the preset power semiconductor device voltage information, the maximum operating voltage corresponding to the target battery cell, and the battery cell interface quantity information.

3. The method for constructing the main circuit of a battery energy storage power station according to claim 2, characterized in that, The step of determining the number of parallel battery branches corresponding to the target battery cell according to the discharge duration includes: Using the discharge duration as a keyword to match the corresponding target application scenario from a preset scenario information table; Determine the number of parallel battery branches corresponding to the target application scenario as the number of parallel battery branches corresponding to the target battery cell.

4. The method for constructing the main circuit of a battery energy storage power station according to claim 2, characterized in that, The preset power semiconductor device voltage information includes the rated voltage of the preset power semiconductor device and the voltage margin of the preset power semiconductor device; the step of determining the number of series-connected battery cells in a single path corresponding to the target battery cell according to the preset power semiconductor device voltage information, the maximum operating voltage corresponding to the target battery cell, and the battery cell interface quantity information includes: Calculate the ratio of the rated voltage of the preset power semiconductor device, the voltage margin of the preset power semiconductor device, and the maximum operating voltage corresponding to the target battery cell to obtain the initial number of series-connected battery cells in a single path; Select the smallest multiple value greater than the initial number of series-connected battery cells in a single path from the multiple values corresponding to the battery cell interface quantity information; Determine the smallest multiple value as the number of series-connected battery cells in a single path corresponding to the target battery cell.

5. The method for constructing the main circuit of a battery energy storage power station according to claim 1, characterized in that, The battery cell parameters include the rated voltage of the battery cell and the capacity of the battery cell; the step of determining the total number of initial H-bridge modules according to the battery quantity information, the energy storage power station capacity requirement information, and the battery cell parameters corresponding to the target battery cell includes: Calculate the battery quantity information, the rated voltage of the battery cell, and the capacity of the battery cell to obtain the rated module capacity corresponding to a single H-bridge module; Calculate the ratio of the total capacity of the energy storage power station corresponding to the energy storage power station capacity requirement information to the rated module capacity to determine the total number of initial H-bridge modules.

6. The method for constructing the main circuit of a battery energy storage power station according to claim 2, characterized in that, The step of constructing the main circuit of the battery energy storage power station based on the cascaded multilevel topology by using H-bridge modules corresponding to the total number of H-bridge modules and the target battery cells corresponding to the battery quantity information, in combination with the number of parallel cascaded multilevel energy storage converters and the number of H-bridge modules, includes: Construct battery branches by using the target battery cells corresponding to the number of series-connected battery cells in a single path; Select the H-bridge modules corresponding to the total number of H-bridge modules; Connect the battery branches to the DC sides of the respective H-bridge modules according to the number of the parallel battery branches, and combine the number of the H-bridge modules to obtain a single cascaded multilevel energy storage converter. Parallelly connect the respective cascaded multilevel energy storage converters according to the number of the cascaded multilevel energy storage converters in parallel, and connect them to the bus corresponding to the battery energy storage power station to obtain the main circuit of the battery energy storage power station.

7. A system for constructing the main circuit of a battery energy storage power station Characterized in that it includes: A target battery cell selection module, configured to select a target battery cell according to the energy storage power station capacity demand information when receiving the energy storage power station capacity demand information; A battery quantity information determination module, configured to determine the battery quantity information of the target battery cell based on the maximum operating voltage corresponding to the target battery cell and the energy storage power station capacity demand information; An initial total number of H-bridge modules determination module, configured to determine the initial total number of H-bridge modules according to the battery quantity information, the energy storage power station capacity demand information, and the battery cell parameters corresponding to the target battery cell; An H-bridge module quantity information and cascaded multilevel energy storage converter parallel quantity determination module, configured to determine the number of H-bridge modules required for a single cascaded multilevel energy storage converter, the total number of H-bridge modules, and the number of cascaded multilevel energy storage converters in parallel according to the preset grid connection parameters and the initial total number of H-bridge modules; A battery energy storage power station main circuit construction module, configured to use H-bridge modules with a quantity corresponding to the total number of the H-bridge modules and the target battery cells with a quantity corresponding to the battery quantity information, and combine the number of cascaded multilevel energy storage converters in parallel and the number of H-bridge modules to construct the main circuit of the battery energy storage power station based on the cascaded multilevel topology; The H-bridge module quantity information and cascaded multilevel energy storage converter parallel quantity determination module includes: A cascaded multilevel energy storage converter H-bridge module quantity determination module, configured to substitute the preset grid connection parameters into the single-phase H-bridge module quantity calculation formula of the preset single cascaded multilevel energy storage converter to determine the number of H-bridge modules required for a single cascaded multilevel energy storage converter; A module ratio obtaining module, configured to calculate the ratio of the initial total number of H-bridge modules to the number of H-bridge modules to obtain a module ratio; An up and down rounding parallel quantity obtaining module, configured to perform a rounding operation on the module ratio to obtain a down-rounded cascaded multilevel energy storage converter parallel quantity and an up-rounded cascaded multilevel energy storage converter parallel quantity; A first initial quantity calculation module, configured to calculate the actual total number of H-bridge modules required under the down-rounded cascaded multilevel energy storage converter parallel quantity to obtain a corresponding first initial quantity; A second initial quantity calculation module, configured to calculate the actual total number of H-bridge modules required under the up-rounded cascaded multilevel energy storage converter parallel quantity to obtain a second initial quantity; A first initial quantity and second initial quantity comparison module, configured to compare the first initial quantity and the second initial quantity; The first comparison result module is configured to, if the first initial quantity is greater than the second initial quantity, use the second initial quantity as the total number of H-bridge modules and use the ceiling cascaded multilevel energy storage converter parallel quantity as the cascaded multilevel energy storage converter parallel quantity; The second comparison result module is configured to, if the first initial quantity is less than the second initial quantity, use the first initial quantity as the total number of H-bridge modules and use the floor cascaded multilevel energy storage converter parallel quantity as the cascaded multilevel energy storage converter parallel quantity.

8. An electronic device, characterized in that, it includes a memory and a processor, and a computer program is stored in the memory. When the computer program is executed by the processor, the processor is caused to execute the steps of the battery energy storage power station main circuit construction method according to any one of claims 1-6.

9. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the computer program is executed, it implements the battery energy storage power station main circuit construction method according to any one of claims 1-6.

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