SOC in-phase equalization control method, energy storage system, device and storage medium

Abstract

The invention discloses an SOC in-phase equalization control method, an energy storage system and device, and a storage medium. The method comprises the steps: obtaining the energy storage amount of an energy storage unit of each power module in each phase of energy storage bridge arm; calculating an energy storage mean value according to the energy storage of all the power modules; calculating the energy storage amount and the energy storage mean value of each power module to obtain an energy storage difference value of each power module; pI adjustment is carried out according to the energy storage difference value of each power module to obtain a modulation parameter of each power module; obtaining the charging and discharging states of the cascaded energy storage system, and setting each modulation parameter according to the charging and discharging states to form each control instruction; controlling the inversion unit of the corresponding power module to act according to each control instruction so as to charge or discharge the energy storage unit; the design ensures stable and reliable operation of the system and reduces the arrangement cost.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid energy storage control, and in particular to a SOC intra-phase balancing control method and an energy storage system, device, and storage medium. Background Art

[0002] Cascade energy storage systems are widely used in new energy power grid systems. The cascade energy storage system schedules the charging and discharging of energy storage, allowing renewable energy power generation to be smoothly controlled, reducing instantaneous power changes and reducing the impact on the power grid.

[0003] A cascade energy storage system usually includes a multi-phase energy storage bridge arm, and each phase energy storage bridge arm includes a plurality of power modules connected in sequence. A control module is respectively connected to each power module to control the switching action of the inverter unit in the power module. The energy storage unit in the power module is charged and discharged to smooth the power supply of the power grid system. Under long-term operation, the energy storage capacity of the energy storage unit in each power module will deviate. Continuing to use it will make the output of the cascade energy storage system unstable. Therefore, for some power modules with large energy storage capacity deviation, it is necessary to remove them, and then perform energy storage capacity equalization and balancing treatment, and then put them into operation after meeting the requirements. However, this method requires the layout of more power modules, which is costly. Alternatively, some cascade energy storage systems will perform voltage equalization and balancing treatment before being put into use. After the service life is reached, the cascade energy storage system will be disconnected from the grid for inspection and maintenance. However, this method wastes time, and the disconnection process will cause instability in the power grid system. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a SOC phase balance control method and an energy storage system, device, and storage medium, which promptly and quickly perform energy storage balance processing during the operation of the power module, ensure stable and reliable operation of the system, and reduce the layout cost.

[0005] According to an embodiment of the first aspect of the present invention, a SOC phase balance control method is applied to a cascade energy storage system, the cascade energy storage system includes at least one phase energy storage bridge arm and a control module, each phase energy storage bridge arm includes a plurality of power modules connected in sequence, the control module is connected to each of the power modules, the power module includes an inverter unit and an energy storage unit, the inverter unit is connected to the energy storage unit, the SOC phase balance control method includes: obtaining the energy storage of the energy storage unit of each power module in each phase energy storage bridge arm; calculating the energy storage mean according to the energy storage of all power modules; respectively calculating the energy storage of each power module and the energy storage mean to obtain the energy storage difference of each power module; performing PI adjustment according to the energy storage difference of each power module to obtain the modulation parameters of each power module; obtaining the charge and discharge state of the cascade energy storage system, setting each modulation parameter according to the charge and discharge state to form each control instruction; controlling the inverter unit of the corresponding power module to act according to each control instruction to charge or discharge the energy storage unit.

[0006] A SOC phase balancing control method according to an embodiment of the present invention has at least the following beneficial effects:

[0007] In the SOC intra-phase balancing control method of the present invention, during the process of the cascade energy storage system being connected to the power grid system and put into operation, the control module obtains the energy storage amount of each power module, thereby obtaining the energy storage difference between each power module and the energy storage mean, and uses the energy storage difference to perform PI adjustment, so that the obtained modulation parameters allow the power module to meet the requirements of the cascade energy storage system for smooth processing of the power grid system without being cut out, and can also adjust the power module with a large energy storage difference during the charging and discharging process of the cascade energy storage system, and finally makes the energy storage amount of each power module return to the touch energy mean as much as possible without large deviation. The design ensures stable and reliable operation of the system and reduces the layout cost.

[0008] According to some embodiments of the present invention, the step of calculating the energy storage amount and the energy storage mean of each power module to obtain the energy storage difference of each power module includes:

[0009] ΔSOC n =SOC m -SOC n ;

[0010] Where n is the identification number of the power module, ΔSOC n is the energy storage difference of the power module with identification number n, SOC m is the energy storage mean, SOC n is the energy storage capacity of the power module with identification number n.

[0011] According to some embodiments of the present invention, performing PI regulation according to the energy storage difference of each power module to obtain the modulation parameters of each power module includes:

[0012] SOC n_cmd =ΔSOC n *K p *K i ;

[0013] Among them, SOC n_cmd is the modulation parameter of the power module with identification number n, K p is the proportionality coefficient, K i is the integration coefficient.

[0014] According to some embodiments of the present invention, the step of setting each modulation parameter according to the charge and discharge state to form each control instruction includes:

[0015] cmd n_out =SOC n_cmd *E;

[0016] Among them, cmd n_out is the control instruction of the power module with identification number n; when the cascade energy storage system is in the charging state, E=a, when the cascade energy storage system is in the discharging state, E=-α, and a is the conversion coefficient.

[0017] According to some embodiments of the present invention, the control module includes a difference calculation thread group, a PI adjustment thread group and an instruction formulation thread group which are arranged in sequence in the processing flow; the difference calculation thread group calculates the energy storage difference of each power module one by one; after the difference calculation thread group completes the calculation of the energy storage difference of a power module, it outputs the energy storage difference result of the power module to the PI adjustment thread group; the PI adjustment thread group calculates the modulation parameters of each power module one by one; after the PI adjustment thread group completes the calculation of the modulation parameters of a power module, it outputs the modulation parameter result of the power module to the instruction formulation thread group; the instruction formulation thread group forms control instructions for each power module one by one.

[0018] According to some embodiments of the present invention, the difference calculation thread group has multiple difference calculation threads, and the difference calculation thread group calculates the energy storage difference of each power module one by one, including: at least one clock cycle as an interval, the energy storage difference calculation steps of each power module are input into the difference calculation thread group for execution in turn.

[0019] According to some embodiments of the present invention, after the instruction formulation thread group completes processing the control instruction of the last power module, it also includes: checking the number of each control instruction, and only when the number of control instructions matches the number of power modules in the cascade energy storage system, executing the steps of controlling the corresponding power module actions according to each control instruction.

[0020] According to the second aspect of the present invention, the cascade energy storage system includes at least one phase energy storage bridge arm and a control module, each phase energy storage bridge arm includes a plurality of power modules connected in sequence, the control module is connected to each of the power modules, the power module includes an inverter unit and an energy storage unit, the inverter unit is connected to the energy storage unit, and the control module executes the SOC phase balancing control method disclosed in any of the above embodiments to control the action of the inverter unit in each power module.

[0021] The cascade energy storage system according to the embodiment of the present invention has at least the following beneficial effects:

[0022] In the cascade energy storage system of the present invention, the control module executes the SOC phase balancing control method to control the action of the inverter unit in each power module, so that when the cascade energy storage system is connected to the power grid system and put into operation, the power module can meet the cascade energy storage system's requirement for smooth processing of the power grid system without being switched out, and can also adjust the power modules with large energy storage differences during the charging and discharging process of the cascade energy storage system, and finally make the storage energy of each power module return to the touch energy mean as much as possible without large deviation. The design ensures stable and reliable operation of the system and reduces the layout cost.

[0023] According to the control device of the third aspect of the embodiment of the present invention, the control device includes a memory and a processor, the memory stores a computer program, and the processor implements the SOC phase balancing control method disclosed in any of the above embodiments when executing the computer program.

[0024] According to the computer-readable storage medium of the fourth aspect of the present invention, the computer-readable storage medium stores a computer program, and is characterized in that when the computer program is executed by a processor, the SOC intra-phase balancing control method disclosed in any of the above embodiments is implemented.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0027] Figure 1It is a schematic diagram of the structure of the power module;

[0028] Figure 2 A schematic diagram of the structure of one embodiment of the cascade energy storage system of the present invention;

[0029] Figure 3 A flow chart of one embodiment of the SOC intra-phase balancing control method of the present invention;

[0030] Figure 4 This is a principle structural block diagram of one embodiment of the control device of the present invention.

[0031] Reference numerals:

[0032] Cascade energy storage system 100; energy storage bridge arm 200; power module 300; inverter unit 410; energy storage unit 420; processor 610; memory 620; input / output interface 630; communication interface 640; bus 650. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0034] It should be noted that, although the functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first", "second", etc. in the specification, claims and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0036] like Figures 1 to 3 As shown, a SOC phase balancing control method according to an embodiment of the first aspect of the present invention is applied to a cascade energy storage system 100, wherein the cascade energy storage system 100 includes at least one phase energy storage bridge arm 200 and a control module, each phase energy storage bridge arm 200 includes a plurality of power modules 300 connected in sequence, the control module is connected to each of the power modules 300, the power module 300 includes an inverter unit 410 and an energy storage unit 420, and the inverter unit 410 is connected to the energy storage unit 420.

[0037] Among them, the cascade energy storage system 100 usually includes a three-phase energy storage bridge arm 200, each energy storage unit 420 can be composed of multiple battery packs or supercapacitors connected in series, the inverter unit 410 can have four semiconductor switching tubes to form an H-bridge inverter circuit, the head and tail ends of the energy storage unit 420 are respectively connected to the DC side of the inverter unit 410, and the AC side of the inverter unit 410 is connected to the AC side of other power modules 300 to form an energy storage bridge arm 200.

[0038] It is understandable that when the cascade energy storage system 100 is connected to the power grid system, when the output of each phase energy storage bridge arm 200 is the power grid charge and discharge modulation, the charge and discharge amount of each power module 300 cannot be completely unified, resulting in deviations in the storage amount of each power module 300 in each phase energy storage bridge arm 200 after a period of use. The power module 300 with a large deviation may not be able to provide the power supply and supply voltage required by the cascade energy storage system 100 during operation, resulting in fluctuations in the power grid system. Therefore, it is necessary to control the storage amount of the power module 300.

[0039] It should be noted that when executing the following SOC intra-phase balancing control method, the power module 300 with a large energy storage amount deviation does not need to be cut out of the energy storage bridge arm 200 .

[0040] The SOC intra-phase balancing control method comprises:

[0041] S510, obtaining the storage energy of the energy storage unit of each power module in each phase energy storage bridge arm;

[0042] S520, calculating the energy storage mean value according to the energy storage amounts of all power modules;

[0043] S530, respectively calculating the energy storage amount and the energy storage mean of each power module to obtain the energy storage difference of each power module;

[0044] S540, performing PI adjustment according to the energy storage difference of each power module to obtain the modulation parameters of each power module;

[0045] S550, acquiring the charge and discharge state of the cascade energy storage system, and setting various modulation parameters according to the charge and discharge state to form various control instructions;

[0046] S560. According to each control instruction, control the inverter unit of the corresponding power module to charge or discharge the energy storage unit.

[0047] Among them, the control module is provided with a power detection module, which is respectively connected to the energy storage unit of each power module. Specifically, the storage capacity of each energy storage unit can be expressed by SOC. SOC (State of Charge) is the state of charge, which is used to measure the remaining power of the battery. SOC reflects the ratio of the remaining capacity of the battery at a certain moment to its capacity in the fully charged state, expressed as a percentage.

[0048] In step 520, the sum of the energy storage of all power modules is calculated and then divided by the number of all power modules to obtain the energy storage mean.

[0049] In the SOC intra-phase balancing control method of the present invention, during the process of the cascade energy storage system being connected to the power grid system and put into operation, the control module obtains the energy storage amount of each power module, thereby obtaining the energy storage difference between each power module and the energy storage mean, and uses the energy storage difference to perform PI adjustment, so that the obtained modulation parameters allow the power module to meet the requirements of the cascade energy storage system for smooth processing of the power grid system without being cut out, and can also adjust the power module with a large energy storage difference during the charging and discharging process of the cascade energy storage system, and finally makes the energy storage amount of each power module return to the touch energy mean as much as possible without large deviation. The design ensures stable and reliable operation of the system and reduces the layout cost.

[0050] In some embodiments of the present invention, the step of calculating the energy storage difference of each power module by respectively calculating the energy storage amount and the energy storage mean of each power module includes:

[0051] ΔSOC n =SOC m -SOC n ;

[0052] Where n is the identification number of the power module, ΔSOC n is the energy storage difference of the power module with identification number n, SOC m is the energy storage mean, SOC n is the energy storage capacity of the power module with identification number n.

[0053] Each power module is distinguished by n, and the energy storage amount, energy storage difference, modulation parameter and control instruction of the power module are matched one by one.

[0054] It is understandable that ΔSOC n Indicates the energy storage difference of the power module with identification number n. When ΔSOC n If ΔSOC is greater than 0, it means that the energy storage of the power module is less than the average energy storage value. n If it is less than 0, it means that the energy storage capacity of the power module is greater than the average energy storage capacity.

[0055] In some embodiments of the present invention, the step of performing PI regulation according to the energy storage difference of each power module to obtain the modulation parameters of each power module includes:

[0056] SOC n_cmd =ΔSOC n *E p *K i ;

[0057] Among them, SOC n_cmd is the modulation parameter of the power module with identification number n, K p is the proportionality coefficient, K i is the integration coefficient.

[0058] Proportional coefficient K p and the integration coefficient K i It can be set by the staff according to the actual requirements of the cascade energy storage system. For the energy storage difference of each power module, combined with the proportional coefficient K that meets the requirements of the cascade energy storage system p and the integration coefficient K i PI regulation is performed to enable the control module to more accurately control the power module according to the control instructions formed by the modulation parameters during the charging and discharging process of the cascade energy storage system. PI regulation enables adaptive adjustment to meet the requirements of the cascade energy storage system for smooth processing of the power grid system when the energy storage difference of some power modules is large, and balances the energy storage of each power module during the charging and discharging process of the cascade energy storage system.

[0059] In some embodiments of the present invention, the step of setting each modulation parameter according to the charge and discharge state to form each control instruction includes:

[0060] cmd n_out =SOC n_cmd *E;

[0061] Among them, cmd n_out is the control instruction of the power module with identification number n; when the cascade energy storage system is in the charging state, E=a, when the cascade energy storage system is in the discharging state, E=-a, and a is the conversion coefficient.

[0062] Among them, a can be formulated by the staff according to the actual signal specifications of the control instruction, so as to convert the modulation parameters into the control instruction.

[0063] The control module can obtain the charging and discharging status of the cascade energy storage system according to the needs of the power grid system. It can be understood that when the cascade energy storage system is in the charging state, the control module uses cmd n_out The inverter units are controlled to conduct from large to small. For power modules with low energy storage, cmd n_outLarger, can increase the turn-on threshold of the inverter unit, absorb more electric energy, and for power modules with higher energy storage, cmd n_out Small, can reduce the opening threshold of the inverter unit, absorb less electric energy, and when the cascade energy storage system is in the discharge state, through cmd n_out The inverter units are controlled to conduct in ascending order. For power modules with low energy storage, cmd n_out Larger, can reduce the turn-on threshold of the inverter unit, release less power, and for power modules with higher energy storage, cmd n_out A smaller value can increase the turn-on threshold of the inverter unit and release more electrical energy.

[0064] In the traditional processing method, when processing steps 530-550, the control module usually takes each power module as a unit, executes steps 530-550 to obtain the control instructions of one power module, and then executes steps 530-550 to obtain the control instructions of the next power module. This method can ensure that the control instructions of each power module are obtained in an orderly manner, but it is not suitable for the present application scheme. Since in the present application, each power module does not cut out the energy storage bridge arm, it needs to have higher timeliness requirements and respond to the changing needs of the power grid in a timely manner to make control.

[0065] Therefore, in some embodiments of the present invention, the control module includes a difference calculation thread group, a PI adjustment thread group, and an instruction formulation thread group which are sequentially arranged in the processing flow;

[0066] The difference calculation thread group calculates the energy storage difference of each power module one by one;

[0067] After the difference calculation thread group completes the calculation of the energy storage difference of each power module, it outputs the energy storage difference result of the power module to the PI adjustment thread group;

[0068] The PI regulation thread group calculates the modulation parameters of each power module one by one;

[0069] After the PI adjustment thread group completes the calculation of the modulation parameters of each power module, it outputs the modulation parameter result of the power module to the instruction formulation thread group;

[0070] The instruction formulation thread group generates control instructions for each power module one by one.

[0071] It can be understood that the control module divides the execution of step 530, step 540 and step 550 into three different threads. After the difference calculation thread group completes the calculation of step 530 of a power module, the energy storage difference result is immediately output to the PI adjustment thread group, and the PI adjustment thread group can process step 540. At this time, the difference calculation thread group can calculate step 530 of the next power module. Similarly, after the PI adjustment thread group completes the calculation of step 540 of a power module, it can output the modulation parameter result to the instruction formulation thread group, and the instruction formulation thread group can process step 550. At this time, the PI adjustment thread group can process step 540 of the next power module. It can be seen that this method greatly improves the processing efficiency and shortens the processing time to meet the control timeliness requirements of the cascade energy storage system.

[0072] In some embodiments of the present invention, the difference calculation thread group has multiple difference calculation threads, and the difference calculation thread group calculates the energy storage difference of each power module one by one, including:

[0073] At intervals of at least one clock cycle, the energy storage difference calculation steps of each power module are sequentially input into the difference calculation thread group for execution.

[0074] It can be understood that in order to further improve the processing efficiency, there can be multiple difference calculation threads in the difference calculation thread group. Similarly, the PI adjustment thread group can also have multiple PI adjustment threads, and the instruction formulation thread group can also have multiple instruction formulation threads. Each difference calculation thread, PI adjustment thread and instruction formulation thread can independently complete the processing of steps 530, 540 and 550 for the power module. However, in order to distinguish the processing data of each power module and reduce the probability of disorder in the processing process, the energy storage difference calculation steps of each power module are input into the difference calculation thread group for execution in turn at an interval of at least one clock cycle, that is, any idle difference calculation thread processes the storage of the first power module. Energy difference calculation, after the preset clock cycle, any remaining idle difference calculation thread will process the energy storage difference calculation of the second power module. Since the processing time of each difference calculation thread is the same, the energy storage difference of the first power module is calculated first, and then it can be input into the PI adjustment thread group. Any idle PI adjustment thread will calculate the modulation parameters of the first power module. After the preset clock cycle, the energy storage difference of the second power module is also calculated and input into the PI adjustment thread group. Any remaining idle PI adjustment thread will calculate the modulation parameters of the second power module. The same is true for multiple instruction formulation threads in the instruction formulation thread group, and so on to derive each control instruction.

[0075] In some embodiments of the present invention, in order to ensure that all control instructions are obtained and prevent the system from crashing due to the imbalance of some power modules, after the instruction formulation thread group completes the processing of the control instructions of the last power module, it also includes: checking the number of each control instruction. When the number of control instructions matches the number of power modules in the cascade energy storage system, the steps of controlling the corresponding power module actions according to each control instruction are executed.

[0076] According to the cascade energy storage system 100 of the second aspect embodiment of the present invention, it includes at least one phase energy storage bridge arm 200 and a control module, each phase energy storage bridge arm 200 includes a plurality of power modules 300 connected in sequence, the control module is connected to each of the power modules 300, the power module 300 includes an inverter unit 410 and an energy storage unit 420, the inverter unit 410 is connected to the energy storage unit 420, and the control module executes the SOC phase balancing control method disclosed in any of the above embodiments to control the action of the inverter unit 410 in each power module 300.

[0077] In the cascaded energy storage system 100 of the present invention, the control module executes the SOC phase balancing control method to control the action of the inverter unit 410 in each power module 300, so that when the cascaded energy storage system 100 is connected to the power grid system and put into operation, the power module 300 can meet the smooth processing requirements of the cascaded energy storage system 100 for the power grid system without being cut out, and can also adjust the power module 300 with a large energy storage difference during the charging and discharging process of the cascaded energy storage system 100, and finally make the storage energy of each power module 300 return to the touch energy mean as much as possible without large deviation. This design ensures stable and reliable operation of the system and reduces the layout cost.

[0078] like Figure 4 As shown, Figure 4 The hardware structure of the control device of another embodiment is also illustrated, and the control device comprises:

[0079] The processor 610 may be implemented by a general-purpose central processing unit 610 (CPU), a microprocessor 610, an application specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application;

[0080] The memory 620 may be implemented in the form of a read-only memory 620 (ROM), a static storage device, a dynamic storage device, or a random access memory 620 (RAM). The memory 620 may store an operating system and other application programs. When the technical solution provided in the embodiment of this specification is implemented by software or firmware, the relevant program code is stored in the memory 620, and the processor 610 calls and executes the SOC phase balancing control method of the embodiment of this application;

[0081] Input / output interface 630, used to implement information input and output;

[0082] Communication interface 640, used to realize communication interaction between the device and other devices, which can be realized through wired mode (such as USB, network cable, etc.) or wireless mode (such as mobile network, WIFI, Bluetooth, etc.);

[0083] bus 650 , which transmits information between the various components of the device (e.g., processor 610 , memory 620 , input / output interface 630 , and communication interface 640 );

[0084] The processor 610 , the memory 620 , the input / output interface 630 , and the communication interface 640 are connected to each other in communication within the device via a bus 650 .

[0085] According to the computer-readable storage medium of the fourth aspect of the present invention, the computer-readable storage medium stores a computer program, which is characterized in that when the computer program is executed by the processor 610, the SOC intra-phase balancing control method disclosed in any of the above embodiments is implemented.

[0086] The memory 620, as a non-transient computer-readable storage medium, can be used to store non-transient software programs and non-transient computer executable programs. In addition, the memory may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some embodiments, the memory 620 may optionally include a memory remotely disposed relative to the processor, and these remote memories may be connected to the processor via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0087] The embodiments described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0088] Those skilled in the art will appreciate that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer steps than shown in the figures, or a combination of certain steps, or different steps.

[0089] The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place or distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0090] Those skilled in the art will appreciate that all or some of the steps in the methods disclosed above, and the functional modules / units in the systems and devices may be implemented as software, firmware, hardware, or a suitable combination thereof.

[0091] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0092] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A SOC phase balance control method, applied to a cascade energy storage system, the cascade energy storage system includes at least one phase energy storage bridge arm and a control module, each phase energy storage bridge arm includes a plurality of power modules connected in sequence, the control module is connected to each of the power modules, the power module includes an inverter unit and an energy storage unit, the inverter unit is connected to the energy storage unit, characterized in that: The SOC phase intra-balance control method comprises: Obtaining the storage energy of the energy storage unit of each power module in each phase energy storage bridge arm; Calculate the energy storage mean value based on the energy storage of all power modules; The energy storage amount and energy storage mean of each power module are calculated respectively to obtain the energy storage difference of each power module; The modulation parameters of each power module are obtained by performing PI adjustment according to the energy storage difference of each power module; Acquire the charging and discharging status of the cascade energy storage system, and set various modulation parameters according to the charging and discharging status to form various control instructions; According to each control instruction, the inverter unit of the corresponding power module is controlled to charge or discharge the energy storage unit.

2. The SOC phase balance control method according to claim 1, characterized in that: The step of calculating the energy storage difference of each power module by respectively calculating the energy storage amount and the energy storage mean of each power module includes: ΔSOC n =SOC m -SOC n ; Where n is the identification number of the power module, ΔSOC n is the energy storage difference of the power module with identification number n, SOC m is the energy storage mean, SOC n is the energy storage capacity of the power module with identification number n.

3. The SOC phase balance control method according to claim 2, characterized in that: The modulation parameters of each power module obtained by performing PI adjustment according to the energy storage difference of each power module include: SOC n_cmd =ΔSOC n *E p *K i ; Among them, SOC n_cmd is the modulation parameter of the power module with identification number n, K p is the proportionality coefficient, K i is the integration coefficient.

4. The SOC phase balance control method according to claim 3, characterized in that: The step of setting each modulation parameter according to the charge and discharge state to form each control instruction includes: cmd n_out =SOC n_cmd *E; Among them, cmd n_out is the control instruction of the power module with identification number n; when the cascade energy storage system is in the charging state, E=a, when the cascade energy storage system is in the discharging state, E=-a, and a is the conversion coefficient.

5. The SOC phase balance control method according to claim 1, characterized in that: The control module includes a difference calculation thread group, a PI adjustment thread group, and an instruction formulation thread group which are sequentially arranged in the processing flow; The difference calculation thread group calculates the energy storage difference of each power module one by one; After the difference calculation thread group completes the calculation of the energy storage difference of each power module, it outputs the energy storage difference result of the power module to the PI adjustment thread group; The PI adjustment thread group calculates the modulation parameters of each power module one by one; after the PI adjustment thread group completes the calculation of the modulation parameters of each power module, it outputs the modulation parameter result of the power module to the instruction formulation thread group; The instruction formulation thread group generates control instructions for each power module one by one.

6. The SOC intra-phase balancing control method according to claim 5, characterized in that: The difference calculation thread group has a plurality of difference calculation threads, and the difference calculation thread group calculates the energy storage difference of each power module one by one, including: At intervals of at least one clock cycle, the energy storage difference calculation steps of each power module are sequentially input into the difference calculation thread group for execution.

7. The SOC phase balance control method according to claim 5, characterized in that: After the instruction formulation thread group completes processing the control instruction of the last power module, it also includes: The number of each control instruction is checked, and when the number of control instructions matches the number of power modules in the cascade energy storage system, the step of controlling the corresponding power module actions according to each control instruction is executed.

8. A cascade energy storage system, characterized in that: It includes at least one phase energy storage bridge arm and a control module, each phase energy storage bridge arm includes a plurality of power modules connected in sequence, the control module is connected to each of the power modules, the power module includes an inverter unit and an energy storage unit, the inverter unit is connected to the energy storage unit, and the control module executes the SOC phase balancing control method as described in any one of claims 1 to 7 to control the action of the inverter unit in each power module.

9. A control device, characterized in that: The control device includes a memory and a processor, the memory stores a computer program, and the processor implements the SOC intra-phase balancing control method according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the SOC intra-phase balancing control method according to any one of claims 1 to 7 is implemented.

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