Method and system for determining optimal link number of energy storage converter

Abstract

The invention provides a method and a system for determining the optimal link number of an energy storage converter. The method comprises the following steps: acquiring rated voltage of a power grid and the maximum value and the minimum value of direct-current voltage of a single energy storage battery; determining the minimum value of the chain link number of the energy storage converter according to the rated voltage of the power grid and the maximum value of the direct-current voltage of the single energy storage battery; determining the maximum value of the chain link number of the energy storage converter according to the rated voltage of the power grid and the minimum value of the direct-current voltage of the single energy storage battery; and determining the optimal chain link number of the energy storage converter based on the minimum value of the chain link number of the energy storage converter and the maximum value of the chain link number of the energy storage converter. According to the technical scheme provided by the invention, the optimal chain link number of the energy storage converter is quickly and accurately determined, the operation reliability and economy of the system are improved, and the engineering implementation cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of grid-connected energy storage systems, and in particular to a method and system for determining the optimal number of links of an energy storage converter. Background Art

[0002] Energy storage converters are key equipment for grid-connected energy storage systems. Each phase converter of high-voltage direct-mounted energy storage is composed of multiple H-bridge topology converters in cascade, which has the advantages of high reliability and redundancy. However, there is no unified mathematical theory to determine the optimal number of links in energy storage converters. Currently, most of them are determined by simulation methods or actual engineering experience. Due to the complexity of the simulation process or the low accuracy of actual engineering experience, it is urgent to propose a solution that can quickly and accurately determine the optimal number of links in energy storage converters. Summary of the invention

[0003] The present application provides a method and system for determining the optimal number of links of an energy storage converter, so as to at least solve the technical problem that the simulation process is complex or the accuracy of actual engineering experience is low.

[0004] A first aspect of the present application provides a method for determining an optimal number of links of an energy storage converter, the method comprising:

[0005] Obtain the rated voltage of the power grid and the maximum and minimum DC voltage of a single energy storage battery;

[0006] Determine the minimum number of energy storage converter links according to the rated voltage of the power grid and the maximum DC voltage of the single energy storage battery;

[0007] Determining the maximum number of energy storage converter links according to the rated voltage of the power grid and the minimum DC voltage of the single energy storage battery;

[0008] The optimal number of links of the energy storage converter is determined based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter.

[0009] Preferably, the minimum number of energy storage converter links is calculated as follows:

[0010]

[0011] Where N min is the minimum number of energy storage converter links, V s is the rated voltage of the grid, V dc_max is the maximum DC voltage of a single energy storage battery, K v K is the normalization coefficient considering the maximum fluctuation of grid voltage. b is the grid voltage unbalance coefficient, K L It is the maximum voltage drop correction factor of the grid-connected reactor.

[0012] Furthermore, the maximum value of the number of links of the energy storage converter is calculated as follows:

[0013]

[0014] Where N max is the maximum value of the number of energy storage converter links, V dc_min It is the minimum DC voltage of a single energy storage battery.

[0015] Further, the determining the optimal number of links of the energy storage converter based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter comprises:

[0016] Determine each positive integer between the minimum number of energy storage converter chain links and the maximum number of energy storage converter chain links;

[0017] Any value among the positive integers is used as the optimal number of links of the energy storage converter.

[0018] The second embodiment of the present application provides a system for determining the optimal number of links of an energy storage converter, including:

[0019] An acquisition module is used to obtain the rated voltage of the power grid and the maximum and minimum values ​​of the DC voltage of a single energy storage battery;

[0020] A first determination module is used to determine the minimum number of energy storage converter links according to the rated voltage of the power grid and the maximum DC voltage of the single energy storage battery;

[0021] A second determination module is used to determine the maximum number of energy storage converter links according to the rated voltage of the power grid and the minimum DC voltage of the single energy storage battery;

[0022] The third determination module is used to determine the optimal number of links of the energy storage converter based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter.

[0023] Preferably, the minimum number of energy storage converter links is calculated as follows:

[0024]

[0025] Where N min is the minimum number of energy storage converter links, V s is the rated voltage of the grid, V dc_max is the maximum DC voltage of a single energy storage battery, K v K is the normalization coefficient considering the maximum fluctuation of grid voltage. bis the grid voltage unbalance coefficient, K L It is the maximum voltage drop correction factor of the grid-connected reactor.

[0026] Furthermore, the maximum value of the number of links of the energy storage converter is calculated as follows:

[0027]

[0028] Where N max is the maximum value of the number of energy storage converter links, V dc_min It is the minimum DC voltage of a single energy storage battery.

[0029] Furthermore, the third determination module is also used for:

[0030] Determine each positive integer between the minimum number of energy storage converter chain links and the maximum number of energy storage converter chain links;

[0031] Any value among the positive integers is used as the optimal number of links of the energy storage converter.

[0032] The third aspect of the present application provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in the first aspect is implemented.

[0033] A fourth aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method described in the first aspect of the present application.

[0034] The technical solution provided by the embodiments of the present application brings at least the following beneficial effects:

[0035] The present application proposes a method and system for determining the optimal number of links of an energy storage converter, the method comprising: obtaining the rated voltage of the power grid and the maximum and minimum values ​​of the DC voltage of a single energy storage battery; determining the minimum number of links of the energy storage converter according to the rated voltage of the power grid and the maximum value of the DC voltage of the single energy storage battery; determining the maximum number of links of the energy storage converter according to the rated voltage of the power grid and the minimum value of the DC voltage of the single energy storage battery; determining the optimal number of links of the energy storage converter based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter. The technical solution proposed in the present application quickly and accurately determines the optimal number of links of the energy storage converter, improves the reliability and economy of system operation, and reduces the cost of project implementation.

[0036] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0038] Figure 1 A flowchart of a method for determining the optimal number of links of an energy storage converter provided according to an embodiment of the present application;

[0039] Figure 2 A schematic diagram of an energy storage converter chain link provided according to an embodiment of the present application;

[0040] Figure 3 The present invention is a structural diagram of a system for determining the optimal number of links of an energy storage converter according to an embodiment of the present application. DETAILED DESCRIPTION

[0041] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0042] The present application proposes a method and system for determining the optimal number of links of an energy storage converter, the method comprising: obtaining the rated voltage of the power grid, the maximum and minimum values ​​of the DC voltage of a single energy storage battery; determining the minimum number of links of the energy storage converter according to the rated voltage of the power grid and the maximum value of the DC voltage of the single energy storage battery; determining the maximum number of links of the energy storage converter according to the rated voltage of the power grid and the minimum value of the DC voltage of the single energy storage battery; determining the optimal number of links of the energy storage converter based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter. The technical solution proposed in the present application quickly and accurately determines the optimal number of links of the energy storage converter, improves the reliability and economy of system operation, and reduces the cost of project implementation.

[0043] A method and system for determining the optimal number of links of an energy storage converter according to an embodiment of the present application will be described below with reference to the accompanying drawings.

[0044] Embodiment 1

[0045] Figure 1 Flow chart of a method for determining the optimal number of links of an energy storage converter according to one embodiment of the present application, such as Figure 1 As shown, the method includes:

[0046] Step 1: Obtain the rated voltage of the grid and the maximum and minimum DC voltage of a single energy storage battery.

[0047] Step 2: Determine the minimum number of energy storage converter links according to the rated voltage of the power grid and the maximum DC voltage of the single energy storage battery.

[0048] In the embodiment of the present disclosure, the minimum number of energy storage converter links is calculated as follows:

[0049]

[0050] Where N min is the minimum number of energy storage converter links, V s is the rated voltage of the grid, V dc_max is the maximum DC voltage of a single energy storage battery, K v K is the normalization coefficient considering the maximum fluctuation of grid voltage. b is the grid voltage unbalance coefficient, K L It is the maximum voltage drop correction factor of the grid-connected reactor.

[0051] Step 3: Determine the maximum number of energy storage converter links according to the rated voltage of the power grid and the minimum DC voltage of the single energy storage battery.

[0052] In the embodiment of the present disclosure, the maximum value of the number of links of the energy storage converter is calculated as follows:

[0053]

[0054] Where N max is the maximum value of the number of energy storage converter links, V dc_min It is the minimum DC voltage of a single energy storage battery.

[0055] Step 4: Determine the optimal number of links of the energy storage converter based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter.

[0056] In the embodiment of the present disclosure, step 4 specifically includes:

[0057] Determine each positive integer between the minimum number of energy storage converter chain links and the maximum number of energy storage converter chain links;

[0058] Any value among the positive integers is used as the optimal number of links of the energy storage converter.

[0059] For example, Figure 2 As shown, the energy storage system is connected to the three-phase ABC power grid through the energy storage converter. Each phase is composed of a multi-link H-bridge cascade. For example, phase A is composed of links such as A1, A2, An, and phases B and C are similar.

[0060] Assuming the number of links of each phase energy storage converter is N, the voltage balance formula can be obtained:

[0061]

[0062] Wherein, Vdc is the DC voltage of a single energy storage battery (Vdc reflects the state of the energy storage battery and is a variable), Vs is the rated voltage of the grid, Kv is the normalization coefficient considering the maximum fluctuation of the grid voltage, Kb is the grid voltage unbalance coefficient, and KL is the maximum voltage drop correction coefficient of the grid-connected reactor.

[0063] Such as K v Generally, 1.1 is taken. b Generally, 1.02 is taken. L It can be taken as 1.15, so the range of expression of the number of chain links N can be expressed as:

[0064]

[0065] Based on the number of chain links obtained by formula (2), it can be appropriately increased or decreased according to the different redundant operation requirements of the energy storage converter, which greatly improves the calculation efficiency of engineering selection.

[0066] Assuming that the voltage level of the three-phase high voltage ABC is Vs=35000V, and the Udc range reflecting the state of the energy storage battery is 734V to 958V, the range of N can be obtained from formula (2) as 39 to 50. Considering redundant operation and economy, taking N as 42 can meet the design requirements, where N can be any integer from 39 to 50.

[0067] In summary, the present embodiment proposes a method for determining the optimal number of links of an energy storage inverter. The method not only takes into account the voltage imbalance of the power grid, but also takes into account factors such as the voltage drop of the grid-connected reactor and the change in battery status. It can quickly and accurately determine the optimal number of links of the energy storage inverter, thereby improving the reliability and economy of system operation and reducing the cost of project implementation.

[0068] Embodiment 2

[0069] Figure 3 FIG. 1 is a structural diagram of a system for determining the optimal number of links of an energy storage converter according to an embodiment of the present application, such as Figure 3 As shown, the system comprises:

[0070] The acquisition module 100 is used to obtain the rated voltage of the power grid and the maximum and minimum values ​​of the DC voltage of a single energy storage battery;

[0071] A first determination module 200 is used to determine the minimum number of energy storage converter links according to the rated voltage of the power grid and the maximum DC voltage of the single energy storage battery;

[0072] The calculation formula for the minimum number of energy storage converter links is as follows:

[0073]

[0074] Where N min is the minimum number of energy storage converter links, V s is the rated voltage of the grid, V dc_max is the maximum DC voltage of a single energy storage battery, K v K is the normalization coefficient considering the maximum fluctuation of grid voltage. b is the grid voltage unbalance coefficient, K L It is the maximum voltage drop correction factor of the grid-connected reactor.

[0075] A second determination module 300 is used to determine the maximum number of energy storage converter links according to the rated voltage of the power grid and the minimum DC voltage of the single energy storage battery;

[0076] The maximum value of the number of energy storage converter links is calculated as follows:

[0077]

[0078] Where N max is the maximum value of the number of energy storage converter links, V dc_min It is the minimum DC voltage of a single energy storage battery.

[0079] The third determination module 400 is used to determine the optimal number of links of the energy storage converter based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter.

[0080] Furthermore, the third determining module 400 is further configured to:

[0081] Determine each positive integer between the minimum number of energy storage converter chain links and the maximum number of energy storage converter chain links;

[0082] Any value among the positive integers is used as the optimal number of links of the energy storage converter.

[0083] In summary, the system for determining the optimal number of links of an energy storage converter proposed in this embodiment can quickly and accurately determine the optimal number of links of the energy storage converter, thereby improving the reliability and economy of system operation and reducing the cost of project implementation.

[0084] Embodiment 3

[0085] In order to implement the above embodiments, the present disclosure further proposes an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method described in Embodiment 1 is implemented.

[0086] Embodiment 4

[0087] In order to implement the above embodiments, the present disclosure further proposes a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the method described in the first embodiment is implemented.

[0088] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0089] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0090] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A method for determining the optimal number of links of an energy storage converter, characterized in that: The method comprises: Obtain the rated voltage of the power grid and the maximum and minimum DC voltage of a single energy storage battery; Determine the minimum number of energy storage converter links according to the rated voltage of the power grid and the maximum DC voltage of the single energy storage battery; Determining the maximum number of energy storage converter links according to the rated voltage of the power grid and the minimum DC voltage of the single energy storage battery; The optimal number of links of the energy storage converter is determined based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter.

2. The method according to claim 1, characterized in that The calculation formula for the minimum number of energy storage converter links is as follows: Where N min is the minimum number of energy storage converter links, V s is the rated voltage of the grid, V dc_max is the maximum DC voltage of a single energy storage battery, K v K is the normalization coefficient considering the maximum fluctuation of grid voltage. b is the grid voltage unbalance coefficient, K L It is the maximum voltage drop correction factor of the grid-connected reactor.

3. The method according to claim 2, characterized in that The calculation formula for the maximum number of energy storage converter links is as follows: Where N max is the maximum value of the number of energy storage converter links, V dc_min It is the minimum DC voltage of a single energy storage battery.

4. The method according to claim 3, characterized in that The determining the optimal number of links of the energy storage converter based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter comprises: Determine each positive integer between the minimum number of energy storage converter chain links and the maximum number of energy storage converter chain links; Any value among the positive integers is used as the optimal number of links of the energy storage converter.

5. A system for determining the optimal number of links of an energy storage converter, characterized in that: The system comprises: An acquisition module is used to obtain the rated voltage of the power grid and the maximum and minimum values ​​of the DC voltage of a single energy storage battery; A first determination module is used to determine the minimum number of energy storage converter links according to the rated voltage of the power grid and the maximum DC voltage of the single energy storage battery; A second determination module is used to determine the maximum number of energy storage converter links according to the rated voltage of the power grid and the minimum DC voltage of the single energy storage battery; The third determination module is used to determine the optimal number of links of the energy storage converter based on the minimum number of links of the energy storage converter and the maximum number of links of the energy storage converter.

6. The system according to claim 5, characterized in that The calculation formula for the minimum number of energy storage converter links is as follows: Where N min is the minimum number of energy storage converter links, V s is the rated voltage of the grid, V dc_max is the maximum DC voltage of a single energy storage battery, K v K is the normalization coefficient considering the maximum fluctuation of grid voltage. b is the grid voltage unbalance coefficient, K L It is the maximum voltage drop correction factor of the grid-connected reactor.

7. The system according to claim 6, characterized in that The calculation formula for the maximum number of energy storage converter links is as follows: Where N max is the maximum value of the number of energy storage converter links, V dc_min It is the minimum DC voltage of a single energy storage battery.

8. The system according to claim 7, characterized in that The third determination module is further used for: Determine each positive integer between the minimum number of energy storage converter chain links and the maximum number of energy storage converter chain links; Any value among the positive integers is used as the optimal number of links of the energy storage converter.

9. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method according to any one of claims 1 to 4 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 4 is implemented.

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