Parallel control method for energy storage converters and energy storage converters

Abstract

This invention relates to the field of power supply technology, providing a parallel control method for energy storage converters and an energy storage converter itself. The method is applied to a target energy storage converter; the target energy storage converter is any one of the energy storage converters in an energy storage converter system, and the energy storage converters in the system do not communicate with each other. The method includes: obtaining the code of the target energy storage converter and determining the delay time of the target energy storage converter based on the code; when a parallel control command is received from a host computer, after the aforementioned delay time, controlling the target energy storage converter to connect to the parallel control point. The delay times of each energy storage converter in the energy storage converter system are different. In this invention, the target energy storage converter determines its delay time based on its own code, and the energy storage converters in the system connect to the parallel control point in a time-sharing manner, preventing output oscillations and improving the stability of the energy storage converter system.

Description

Technical Field

[0001] This invention belongs to the field of power supply technology, and particularly relates to a parallel control method for an energy storage converter and an energy storage converter. Background Technology

[0002] A power conversion system (PCS) controls the charging and discharging process of a battery, converting AC to DC power. It can directly supply power to AC loads in the absence of a power grid and is widely used in grid operations. In practical applications, to ensure power supply stability, multiple power conversion systems are typically connected in parallel.

[0003] In existing technologies, if multiple energy storage converters are operated in parallel without communication interconnection, it will cause output oscillations and affect the stability of the system. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a parallel control method for energy storage converters and an energy storage converter, so as to solve the problem of multiple energy storage converters operating in parallel at the same time in the prior art, which affects the stability of the system.

[0005] A first aspect of this invention provides a parallel control method for an energy storage converter, applied to a target energy storage converter; the target energy storage converter is any one of the energy storage converters in an energy storage converter system, and the energy storage converters in the system do not communicate with each other; the method includes:

[0006] Obtain the code of the target energy storage converter, and determine the delay time of the target energy storage converter based on the code;

[0007] When a parallel operation command is received from the host computer, after the aforementioned delay time, the target energy storage converter is controlled to connect to the parallel operation point.

[0008] Among them, the parallel connection point is the parallel node where each energy storage converter in the energy storage converter system is coupled; the codes of each energy storage converter in the energy storage converter system are different, and the delay time of each energy storage converter in the energy storage converter system is different; the host computer sends parallel connection commands to each energy storage converter in the energy storage converter system at the same time.

[0009] A second aspect of the present invention provides an energy storage converter, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the parallel control method for the energy storage converter provided in the first aspect of the present invention.

[0010] A third aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the energy storage converter parallel control method provided in the first aspect of the present invention.

[0011] This invention provides a parallel control method for energy storage converters and an energy storage converter itself. The method is applied to a target energy storage converter, which is any one of the energy storage converters in an energy storage converter system, and the energy storage converters in the system do not communicate with each other. The method includes: obtaining the code of the target energy storage converter and determining the delay time of the target energy storage converter based on the code; when a parallel control command is received from a host computer, after the aforementioned delay time, controlling the target energy storage converter to connect to the parallel control point. Each energy storage converter in the energy storage converter system has a different code and a different delay time. In this invention, the energy storage converter determines its delay time based on its own code, and each energy storage converter in the system connects to the parallel control point in a time-sharing manner after receiving the parallel control command from the host computer, preventing output oscillations and improving the stability of the energy storage converter system. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the energy storage converter system provided in an embodiment of the present invention;

[0014] Figure 2 This is a schematic diagram illustrating the implementation process of a parallel control method for an energy storage converter provided in an embodiment of the present invention;

[0015] Figure 3 This is a schematic diagram of the parallel control device for energy storage converters provided in an embodiment of the present invention;

[0016] Figure 4 This is a schematic diagram of the energy storage converter provided in an embodiment of the present invention. Detailed Implementation

[0017] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0018] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0019] Figure 1 A schematic diagram of an energy storage converter system is shown. The system includes at least two energy storage converters 11, each connected to a parallel connection point A via an AC switch S. In existing technologies, the energy storage converters 11 in an energy storage converter system do not communicate with each other. A host computer 12 sends parallel connection commands to each energy storage converter 11 to control the initiation of parallel operation. Therefore, one energy storage converter 11 cannot know the parallel operation status of other energy storage converters 11 in the system. Consequently, if two or more energy storage converters 11 are simultaneously connected in parallel, the different output voltages of each converter 11 will cause output voltage oscillations, affecting the stability of the system.

[0020] Based on the above, refer to Figure 2 This invention provides a parallel control method for an energy storage converter, applied to a target energy storage converter; the target energy storage converter is any one of the energy storage converters in an energy storage converter system, and the energy storage converters in the system do not communicate with each other; the method includes:

[0021] S101: Obtain the code of the target energy storage converter and determine the delay time of the target energy storage converter based on the code of the target energy storage converter;

[0022] S102: When a parallel operation command is received from the host computer, after the above-mentioned delay time, the target energy storage converter is controlled to connect to the parallel operation point.

[0023] Among them, the parallel connection point is the parallel node where each energy storage converter in the energy storage converter system is coupled; the codes of each energy storage converter in the energy storage converter system are different, and the delay time of each energy storage converter in the energy storage converter system is different; the host computer sends parallel connection commands to each energy storage converter in the energy storage converter system at the same time.

[0024] In this embodiment of the invention, the target energy storage converter (any one of the energy storage converters in the energy storage converter system) determines its delay time based on its own code, and controls itself to operate in parallel after the delay time. The energy storage converter system includes a host computer and at least two energy storage converters. During startup, the host computer simultaneously sends parallel operation commands to each energy storage converter. After receiving the parallel operation command from the host computer, each energy storage converter applies the above method for control. Since the codes and delay times of each energy storage converter are different, the startup order of each energy storage converter can be determined without communication, and they start up in a time-sharing manner according to this order, which will not cause output oscillation and improves the stability of the system.

[0025] Meanwhile, since each energy storage converter in the system independently controls itself using the same control method after receiving the parallel operation command from the host computer, it is easy to deploy, flexible to configure, and suitable for various application scenarios.

[0026] In some embodiments, S101 may include:

[0027] S1011: Multiply the code of the target energy storage converter by a preset time interval to obtain the delay time of the target energy storage converter.

[0028] In some embodiments, the energy storage converters in the energy storage converter system are coded as integers from 1 to N;

[0029] Where N is the total number of energy storage converters in the energy storage converter system.

[0030] In this embodiment of the invention, the code of the energy storage converter is multiplied by a preset time interval to obtain the delay time of the target energy storage converter. For example, if there are five energy storage converters in the energy storage converter system, and the codes of each energy storage converter are 1, 2, 3, 4, and 5, then the delay times of each energy storage converter are 1T, 2T, 3T, 4T, and 5T, respectively. Each energy storage converter starts up in a time-sharing manner, which is a simple and effective method.

[0031] In some embodiments, the preset time interval is 5 seconds.

[0032] The preset time interval should take into account both stability and parallel operation time, and can be set according to actual application requirements.

[0033] In some embodiments, the above method may further include:

[0034] S103: When the target energy storage converter is detected to be connected to the parallel point, control the target energy storage converter to switch to VSG mode.

[0035] In some embodiments, reference is made to Figure 1 The target energy storage converter is connected to the parallel point A through the target AC switch (S);

[0036] S102 may include:

[0037] S1021: Real-time acquisition of voltage at the parallel operation point;

[0038] S1022: When the voltage at the paralleling point is not less than the preset voltage, the target energy storage converter is soft-started according to the voltage at the paralleling point, and when the output voltage of the target energy storage converter is synchronized with the voltage at the paralleling point, the target AC switch is closed.

[0039] In this embodiment of the invention, when the voltage at the paralleling point is detected to be not less than a preset voltage (the paralleling point has voltage), that is, the energy storage converter system is connected to the AC grid, or there is currently another energy storage converter connected to the paralleling point. At this time, since the output voltage of the target energy storage converter is 0, directly connecting it to the paralleling point would cause oscillations in the system output voltage. Therefore, the target energy storage converter needs to be soft-started, and connected to the paralleling point only when the output voltage of the target energy storage converter is synchronized with the voltage of the paralleling point. This will prevent oscillations in the output voltage and ensure the stability of the system.

[0040] The preset voltage is used to determine whether there is voltage at the parallel connection point and can be set according to actual application requirements. For example, the preset voltage can be 1V.

[0041] In some embodiments, S1022 may include:

[0042] 1. Use the voltage at the paralleling point as a setpoint to perform phase-locked loop control on the output voltage of the target energy storage converter.

[0043] In some embodiments, S102 may further include:

[0044] S1023: When the voltage at the parallel point is less than the preset voltage, the target AC switch is closed.

[0045] In this embodiment of the invention, when the voltage at the paralleling point is detected to be lower than the preset voltage (no voltage at the paralleling point), that is, the energy storage converter system is not connected to the AC grid, and there are currently no other energy storage converters connected to the paralleling point, only the target energy storage converter is connected to the paralleling point. The output voltage of the target energy storage converter is the system output voltage, which will not affect other energy storage converters. Direct paralleling is possible without soft starting, shortening the startup time and improving control efficiency.

[0046] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0047] Corresponding to the above embodiments, refer to Figure 3This invention also provides a parallel control device for an energy storage converter, applied to a target energy storage converter; the target energy storage converter is any one of the energy storage converters in the energy storage converter system, and the energy storage converters in the energy storage converter system do not communicate with each other; the device includes:

[0048] The delay time determination module 21 is used to obtain the code of the target energy storage converter and determine the delay time of the target energy storage converter based on the code of the target energy storage converter;

[0049] The parallel control module 22 is used to control the target energy storage converter to connect to the parallel point after a delay of the aforementioned delay time when it receives the parallel command sent by the host computer; wherein, the parallel point is the parallel node where each energy storage converter in the energy storage converter system is coupled; the codes of each energy storage converter in the energy storage converter system are different, and the delay time of each energy storage converter in the energy storage converter system is different; the host computer simultaneously sends the parallel command to each energy storage converter in the energy storage converter system.

[0050] In some embodiments, the delay time determination module 21 may include:

[0051] The delay determination unit 211 is used to multiply the code of the target energy storage converter by a preset time interval to obtain the delay time of the target energy storage converter.

[0052] In some embodiments, the codes for each energy storage converter in the energy storage converter system can be integers from 1 to N;

[0053] Where N is the total number of energy storage converters in the energy storage converter system.

[0054] In some embodiments, the preset time interval can be 5 seconds.

[0055] In some embodiments, the above-described apparatus may further include:

[0056] The mode switching module 23 is used to control the target energy storage converter to switch to VSG mode when the target energy storage converter is detected to be connected to the parallel point.

[0057] In some embodiments, the target energy storage converter is connected to the paralleling point via a target AC switch; the paralleling control module 22 may include:

[0058] Voltage acquisition unit 221 is used to acquire the voltage of the parallel operation point in real time;

[0059] The first switch control unit 222 is used to soft-start the target energy storage converter according to the voltage of the paralleling point when the voltage of the paralleling point is not less than the preset voltage, and to control the target AC switch to close when the output voltage of the target energy storage converter is synchronized with the voltage of the paralleling point.

[0060] In some embodiments, the first switch control unit 222 may be specifically used to perform phase-locked loop control on the output voltage of the target energy storage converter using the voltage of the parallel point as a given value.

[0061] In some embodiments, the parallel operation control module 22 may further include:

[0062] The second switch control unit 223 is used to control the target AC switch to close when the voltage at the parallel point is less than the preset voltage.

[0063] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the energy storage converter can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above device can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0064] Figure 4 This is a schematic block diagram of an energy storage converter provided in an embodiment of the present invention. Figure 4 As shown, the energy storage converter 4 in this embodiment includes: one or more processors 40, a memory 41, and a computer program 42 stored in the memory 41 and executable on the processor 40. When the processor 40 executes the computer program 42, it implements the steps in the above-described embodiments of the parallel control method for energy storage converters, for example... Figure 2 The steps S101 to S102 are shown. Alternatively, when the processor 40 executes the computer program 42, it implements the functions of each module / unit in the above-described embodiment of the energy storage converter parallel operation control device, for example... Figure 3 The functions of modules 21 and 22 shown.

[0065] Exemplarily, the computer program 42 can be divided into one or more modules / units, one or more of which are stored in the memory 41 and executed by the processor 40 to complete this application. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which describe the execution process of the computer program 42 in the energy storage converter 4. For example, the computer program 42 can be divided into a delay time determination module 21 and a parallel operation control module 22.

[0066] The delay time determination module 21 is used to obtain the code of the target energy storage converter and determine the delay time of the target energy storage converter based on the code of the target energy storage converter;

[0067] The parallel control module 22 is used to control the target energy storage converter to connect to the parallel point after a delay of the aforementioned delay time when it receives the parallel command sent by the host computer; wherein, the parallel point is the parallel node where each energy storage converter in the energy storage converter system is coupled; the codes of each energy storage converter in the energy storage converter system are different, and the delay time of each energy storage converter in the energy storage converter system is different; the host computer simultaneously sends the parallel command to each energy storage converter in the energy storage converter system.

[0068] Other modules or units will not be described in detail here.

[0069] The energy storage converter 4 includes, but is not limited to, a processor 40 and a memory 41. Those skilled in the art will understand that... Figure 4 This is merely an example of an energy storage converter and does not constitute a limitation on the energy storage converter 4. It may include more or fewer components than shown, or combine certain components, or different components. For example, the energy storage converter 4 may also include input devices, output devices, network access devices, buses, etc.

[0070] The processor 40 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0071] The memory 41 can be an internal storage unit of the energy storage converter, such as the hard drive or RAM of the energy storage converter. The memory 41 can also be an external storage device of the energy storage converter, such as a plug-in hard drive, Smart Media Card (SMC), Secure Digital (SD) card, or Flash Card equipped on the energy storage converter. Furthermore, the memory 41 can include both internal storage units and external storage devices of the energy storage converter. The memory 41 is used to store the computer program 42 and other programs and data required by the energy storage converter. The memory 41 can also be used to temporarily store data that has been output or will be output.

[0072] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0073] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0074] In the embodiments provided in this application, it should be understood that the disclosed energy storage converter and method can be implemented in other ways. For example, the energy storage converter embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0075] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0076] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0077] If an integrated module / unit is implemented as 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, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0078] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for controlling parallel operation of energy storage converters, characterized by, The application is applied to a target energy storage converter; the target energy storage converter is any one of energy storage converters in an energy storage converter system, and the energy storage converters in the energy storage converter system do not communicate with each other; the method comprises the following steps: An encoding of the target energy storage converter is acquired, and a delay time of the target energy storage converter is determined according to the encoding of the target energy storage converter; When a parallel operation instruction sent by a host computer is received, the target energy storage converter is controlled to access a parallel operation point after a delay of the delay time; The parallel operation point is a parallel node to which the energy storage converters in the energy storage converter system are coupled; the encodings of the energy storage converters in the energy storage converter system are all different, and the delay times of the energy storage converters in the energy storage converter system are all different; the host computer simultaneously sends parallel operation instructions to the energy storage converters in the energy storage converter system; The target energy storage converter is connected to the parallel operation point through a target AC switch; the control of the target energy storage converter to access the parallel operation point comprises the following steps: The voltage of the parallel operation point is acquired in real time; When the voltage of the parallel operation point is not less than a preset voltage, the target energy storage converter is soft-started according to the voltage of the parallel operation point, and when the output voltage of the target energy storage converter is synchronized with the voltage of the parallel operation point, the target AC switch is controlled to be closed; When the voltage of the parallel operation point is less than the preset voltage, the target AC switch is controlled to be closed.

2. The energy storage converter parallel operation control method of claim 1, wherein, The determination of the delay time of the target energy storage converter according to the encoding of the target energy storage converter comprises the following steps: The encoding of the target energy storage converter is multiplied by a preset time interval to obtain the delay time of the target energy storage converter.

3. The energy storage inverter parallel operation control method of claim 2, wherein, The encoding of each energy storage converter in the energy storage converter system is an integer in 1 to N; N is the total number of energy storage converters in the energy storage converter system.

4. The energy storage converter parallel operation control method of claim 3, wherein, The preset time interval is 5 s.

5. The energy storage inverter parallel operation control method of claim 1, wherein, The method further comprises the following steps: When it is detected that the target energy storage converter accesses the parallel operation point, the target energy storage converter is controlled to be switched to a VSG mode.

6. The energy storage inverter parallel operation control method of claim 1, wherein, The soft-starting of the target energy storage converter according to the voltage of the parallel operation point comprises the following steps: The voltage of the parallel operation point is used as a given value to perform phase-locked loop control on the output voltage of the target energy storage converter.

7. An energy storage converter comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, The processor executes the computer program to realize the steps of the energy storage converter parallel operation control method according to any one of claims 1 to 6.

8. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1 to 7. The computer program is executed by the processor to realize the steps of the energy storage converter parallel operation control method according to any one of claims 1 to 6.

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