A multi-stage power control method and system for an AC / DC integrated energy storage unit

Abstract

This application provides a multi-level power control method for an AC / DC integrated energy storage unit, comprising: setting an optimal operating power value W1 and a suboptimal operating power value W2 for a single energy storage converter; when the unit controller receives a power command W, comparing the power command W with the total optimal operating power value n1W1 and the total suboptimal operating power value n1W2 of the energy storage converters in a normal, fault-free state; calculating the number of energy storage converters that need to enter the operating state and the power allocated to each energy storage converter entering the operating state based on the comparison results. This application also provides a multi-level power control system for an AC / DC integrated energy storage unit. The multi-level power control method for an AC / DC integrated energy storage unit provided by this invention can achieve simultaneous control of all energy storage converters with minimal energy storage device losses.

Description

Technical Field

[0001] This application relates to the field of power supply technology, specifically to a multi-level power control method and system for an AC / DC integrated energy storage unit. Background Technology

[0002] With the continuous growth of energy demand and increasingly prominent environmental problems, the development and utilization of new energy sources has become an important trend in the global energy development field. Due to the instability and intermittency of new energy sources, their large-scale integration into the power grid can have a significant impact on grid operation.

[0003] Energy storage technology effectively addresses the shortcomings of new energy sources and is therefore widely used in power systems to balance supply and demand, improve renewable energy transfer, and enhance grid reliability and stability. The energy storage converter is the core device of energy storage technology; it is a power electronic device capable of power conversion and control. It can convert DC power stored in energy storage devices (such as lithium battery packs and supercapacitors) into AC power for output to the grid or supply to loads, and can also convert AC power from the grid into DC power for storage. Its core function lies in enabling bidirectional energy flow—it can both discharge to and charge the grid, thereby effectively balancing the supply and demand relationship of the power system. How to control the energy storage converter to better perform energy conversion while meeting usage requirements and extending the device's lifespan is a problem that urgently needs to be solved by those skilled in the art.

[0004] Chinese patent application CN119834321A discloses a parallel control method and system for energy storage converters. It uses a master energy storage converter and N-1 slave energy storage converters (N being a positive integer greater than or equal to 2) connected in parallel between the grid and the load. The system obtains the output current at the load end of the energy storage converters, uses the master energy storage converter to determine the difference between the output current and a preset current threshold, generates a state switching signal, and switches the operating state of the slave energy storage converters. This allows for automatic adjustment of the number of energy storage converters in grid-connected / off-grid mode according to changes in load, improving the conversion efficiency and adaptive capability of the energy storage converters. While meeting user load requirements, it maximizes system benefits. However, the master energy storage converter sends the grid-connected / off-grid operating mode switching signal to the slave energy storage converters, but the signal sending has delays and lags. Furthermore, it does not explain how to achieve simultaneous control of all energy storage converters, the switching control of the standby / operating states of the energy storage converters, or the power control method. Summary of the Invention

[0005] This application provides a multi-level power control method and system for an AC / DC integrated energy storage unit to solve the problems of how to achieve simultaneous control of all energy storage converters, switching control of the standby / operation state of the energy storage converters, and power control methods.

[0006] To address the aforementioned technical problems, this application provides a multi-level power control method for an AC / DC integrated energy storage unit, used in a multi-level power control system for an AC / DC integrated energy storage unit. The multi-level power control system for the AC / DC integrated energy storage unit includes a unit controller and n energy storage converters, each of which is communicatively connected to the unit controller, where n is a non-zero positive integer.

[0007] The multi-level power control method for the AC / DC integrated energy storage unit includes:

[0008] The unit controller sets the optimal operating power value W1 and the suboptimal operating power value W2 for a single energy storage converter;

[0009] When the unit controller receives the power command W, it compares the power command W with the total optimal operating power value n1W1 and the total better operating power value n1W2 of the n1 energy storage converters in normal and fault-free state, where n1 is a non-zero positive integer less than or equal to n, and at least n1 of the n energy storage converters are in normal and fault-free state.

[0010] Based on the comparison results, the number of energy storage converters that need to enter the operating state and the power allocated to each energy storage converter entering the operating state are calculated. The unit controller sends a state switching signal and power value to each of the energy storage converters. After receiving and executing the instruction, each energy storage converter sends its standby / operating state and real-time power value to the unit controller. After receiving the information, the unit controller compares it with the state switching signal and power value sent by the unit controller to ensure that the instruction is executed correctly.

[0011] Furthermore, when W≤n1W1, the unit controller calculates the number n2 of energy storage converters that need to be switched to the operating state based on the principle that the operating power value of a single energy storage converter is less than or equal to W1. n2 is a positive integer less than or equal to n1. The controller issues n2 operating state switching commands to the energy storage converters and, according to the principle of prioritizing the allocation of the optimal operating power value W1, allocates W1 power to the energy storage converters that have switched to the operating state in sequence, so that they enter the optimal operating power state. The last energy storage converter is allocated the remaining power.

[0012] Furthermore, when n1W1<W≤n1W2, the unit controller issues n1 operating state switching commands to the energy storage converter and distributes them to the energy storage converter according to the optimal operating power value W1 and the better operating power value W2, so that the energy storage converter enters the optimal operating power state or the better operating power state, and the last energy storage converter is allocated the remaining power.

[0013] Furthermore, when W > n1W1, the unit controller issues n1 operating state switching commands to the energy storage converter, and allocates power to each energy storage converter as needed according to the power balance distribution principle, so that it enters the balanced power state.

[0014] Furthermore, based on the port position of the energy storage converter connected to the unit controller, the unit controller assigns a fixed number 1 to n to the energy storage converter.

[0015] Furthermore, when W≤n1W1, according to the principle of prioritizing the allocation of the optimal operating power value W1, the energy storage converters that have switched to the operating state are allocated W1 power in sequence according to their number size, so that they enter the optimal operating power state.

[0016] Furthermore, when n1W1<W≤n1W2, the energy storage converter is allocated according to the combination of the optimal operating power value W1 and the relatively optimal operating power value W2, and the allocation is adaptive according to the size of the energy storage converter number, so that the energy storage converter enters the optimal operating power state or the relatively optimal operating power state.

[0017] This application also provides a multi-level power control system for an AC / DC integrated energy storage unit, including: a unit controller and n energy storage converters, wherein each of the energy storage converters is communicatively connected to the unit controller, and n is a non-zero positive integer.

[0018] The multi-level power control system of the AC / DC integrated energy storage unit also includes:

[0019] The setting module allows the unit controller to set the optimal operating power value W1 and the suboptimal operating power value W2 for a single energy storage converter.

[0020] The comparison module compares the power command W with the total optimal operating power value n1W1 and the total relatively optimal operating power value n1W2 of the energy storage converter in a normal and fault-free state, respectively, where n1 is a non-zero positive integer less than or equal to n, and at least n1 of the n energy storage converters are in a normal and fault-free state.

[0021] The allocation module calculates the number of energy storage converters that need to enter the operating state based on the comparison results, as well as the power allocated to each energy storage converter entering the operating state. The unit controller sends a state switching signal and power value to each of the energy storage converters. After receiving and executing the instruction, each energy storage converter sends its standby / operating state and real-time power value to the unit controller. After receiving the information, the unit controller compares it with the state switching signal and power value sent by the unit controller to ensure that the instruction is executed correctly.

[0022] Furthermore, when the configured energy storage system is small in capacity, the multi-level power control system of the AC / DC integrated energy storage unit includes a unit controller, a coordination controller, and n energy storage converters. The coordination controller is connected to the unit controller and controls the unit controller. Each of the energy storage converters is communicatively connected to the unit controller, and n is a non-zero positive integer.

[0023] Furthermore, when the configured energy storage system is small in capacity, the multi-level power control system of the AC / DC integrated energy storage unit includes a coordination controller and n energy storage converters. Each of the energy storage converters is communicatively connected to the coordination controller, where n is a non-zero positive integer.

[0024] Furthermore, when the configured energy storage system has a large capacity, the multi-level power control system of the AC / DC integrated energy storage unit includes multiple unit controllers, a coordination controller, and n energy storage converters. The multiple unit controllers and the coordination controller are connected by optical fiber to form a ring network communication. The coordination controller controls the unit controllers, and each of the energy storage converters is communicatively connected to the unit controller. n is a non-zero positive integer.

[0025] The multi-level power control method for AC / DC integrated energy storage units provided by this invention can simultaneously control all energy storage converters and minimize energy storage device losses. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the multi-level power control system of the AC / DC integrated energy storage unit according to an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] In the description of this application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0030] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0031] Furthermore, the technical features involved in the different embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0032] This application provides a multi-stage power control method for an integrated AC / DC energy storage unit, used in a multi-stage power control system for an integrated AC / DC energy storage unit. Figure 1 This is a schematic diagram of the multi-stage power control system of the AC / DC integrated energy storage unit according to an embodiment of the present invention. (Refer to...) Figure 1 The multi-level power control system of the AC / DC integrated energy storage unit includes a unit controller and n energy storage converters. Each energy storage converter is communicatively connected to the unit controller, and n is a non-zero positive integer.

[0033] The multi-level power control method for the AC / DC integrated energy storage unit includes:

[0034] The unit controller sets the optimal operating power value W1 and the suboptimal operating power value W2 for a single energy storage converter;

[0035] When the unit controller receives the power command W, it compares the power command W with the total optimal operating power value n1W1 and the total better operating power value n1W2 of the n1 energy storage converters in normal and fault-free state, where n1 is a non-zero positive integer less than or equal to n, and at least n1 of the n energy storage converters are in normal and fault-free state.

[0036] Based on the comparison results, the number of energy storage converters that need to enter the operating state and the power allocated to each energy storage converter entering the operating state are calculated. The unit controller sends a state switching signal and power value to each of the energy storage converters. After receiving and executing the instruction, each energy storage converter sends its standby / operating state and real-time power value to the unit controller. After receiving the information, the unit controller compares it with the state switching signal and power value sent by the unit controller to ensure that the instruction is executed correctly.

[0037] When W≤n1W1, the unit controller calculates the number n2 of energy storage converters that need to be switched to the operating state based on the principle that the operating power value of a single energy storage converter is less than or equal to W1. n2 is a positive integer less than or equal to n1. The controller issues n2 operating state switching commands to the energy storage converters and, according to the principle of prioritizing the allocation of the optimal operating power value W1, allocates W1 power to the energy storage converters that have switched to the operating state in sequence, so that they enter the optimal operating power state. The last energy storage converter is allocated the remaining power.

[0038] When n1W1<W≤n1W2, the unit controller sends n1 operating state switching commands to the energy storage converter and distributes them to the energy storage converter according to the optimal operating power value W1 and the better operating power value W2, so that the energy storage converter enters the optimal operating power state or the better operating power state, and the last energy storage converter is allocated the remaining power.

[0039] When W > n1W1, the unit controller sends n1 operating state switching commands to the energy storage converter, and allocates power to each energy storage converter as needed according to the power balance distribution principle, so that it enters the balanced power state.

[0040] In this embodiment of the invention, based on the port position of the energy storage converter connected to the unit controller, the unit controller assigns a fixed number 1 to n to the energy storage converter. When W ≤ n1W1, according to the principle of prioritizing the allocation of the optimal operating power value W1, the energy storage converter switched to the operating state is allocated W1 power sequentially according to its number, so that it enters the optimal operating power state. When n1W1 < W ≤ n1W2, the energy storage converter is allocated according to a combination of the optimal operating power value W1 and the relatively optimal operating power value W2, and the allocation is adaptive according to the energy storage converter number, so that the energy storage converter enters the optimal operating power state or the relatively optimal operating power state.

[0041] This application also provides a multi-level power control system for an AC / DC integrated energy storage unit, including: a unit controller and n energy storage converters, each of the energy storage converters being communicatively connected to the unit controller, where n is a non-zero positive integer; each energy storage converter being directly connected to the unit controller via a physical communication line, and being connected in parallel with each other without affecting each other;

[0042] The multi-level power control system of the AC / DC integrated energy storage unit also includes:

[0043] The setting module allows the unit controller to set the optimal operating power value W1 and the suboptimal operating power value W2 for a single energy storage converter.

[0044] The comparison module compares the power command W with the total optimal operating power value n1W1 and the total relatively optimal operating power value n1W2 of the energy storage converter in a normal and fault-free state, respectively, where n1 is a non-zero positive integer less than or equal to n, and at least n1 of the n energy storage converters are in a normal and fault-free state.

[0045] The allocation module calculates the number of energy storage converters that need to enter the operating state based on the comparison results, as well as the power allocated to each energy storage converter entering the operating state. The unit controller sends a state switching signal and power value to each of the energy storage converters. After receiving and executing the instruction, each energy storage converter sends its standby / operating state and real-time power value to the unit controller. After receiving the information, the unit controller compares it with the state switching signal and power value sent by the unit controller to ensure that the instruction is executed correctly.

[0046] When the configured energy storage system is small-capacity, the multi-stage power control system of the AC / DC integrated energy storage unit includes a unit controller, a coordination controller, and n energy storage converters. The coordination controller is connected to the unit controller and controls the unit controller. Each energy storage converter is communicatively connected to the unit controller. n is a non-zero positive integer. The coordination controller performs multi-stage power control on behalf of the unit controller. Furthermore, when the configured energy storage system is small-capacity, the multi-stage power control system of the AC / DC integrated energy storage unit includes a coordination controller and n energy storage converters. Each energy storage converter is communicatively connected to the coordination controller. n is a non-zero positive integer.

[0047] When the configured energy storage system has a large capacity, the multi-level power control system of the AC / DC integrated energy storage unit includes multiple unit controllers, a coordination controller, and n energy storage converters. The multiple unit controllers and the coordination controller are connected by optical fiber to form a ring network communication. The coordination controller controls the unit controllers. Each of the energy storage converters is communicatively connected to the unit controller. n is a non-zero positive integer. The coordination controller controls multiple unit controllers simultaneously to complete multi-level power control.

[0048] The unit controller power commands include EMS power commands, coordination controller power commands, unit controller's own power commands, and other source power commands.

[0049] The multi-level power control method for AC / DC integrated energy storage units provided by this invention can simultaneously control all energy storage converters and minimize energy storage device losses.

[0050] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A multi-stage power control method for an AC / DC integrated energy storage unit, characterized in that, A multi-level power control system for an AC / DC integrated energy storage unit, the multi-level power control system for the AC / DC integrated energy storage unit includes a unit controller and n energy storage converters, each of the energy storage converters is communicatively connected to the unit controller, and n is a non-zero positive integer; The multi-level power control method for the AC / DC integrated energy storage unit includes: The unit controller sets the optimal operating power value W1 and the suboptimal operating power value W2 for a single energy storage converter; When the unit controller receives the power command W, it compares the power command W with the total optimal operating power value n1W1 and the total better operating power value n1W2 of the n1 energy storage converters in normal and fault-free state, where n1 is a non-zero positive integer less than or equal to n, and at least n1 of the n energy storage converters are in normal and fault-free state. Based on the comparison results, the number of energy storage converters that need to enter the operating state and the power allocated to each energy storage converter entering the operating state are calculated. The unit controller sends a state switching signal and power value to each energy storage converter. After receiving and executing the instruction, each energy storage converter sends its standby / operating state and real-time power value to the unit controller. The unit controller receives the data and compares it with the state switching signal and power value sent by the unit controller to ensure that the instruction is executed correctly. When W≤n1W1, the unit controller calculates the required number of energy storage converters to enter the operating state based on the principle that the operating power value of a single energy storage converter is less than or equal to W1. The number of energy storage converters switched to the operating state is n2, where n2 is a positive integer less than or equal to n1. n2 operating state switching commands are issued to the energy storage converters, and W1 power is allocated to the energy storage converters switched to the operating state in sequence according to the principle of prioritizing the allocation of the optimal operating power value W1. The last energy storage converter is allocated the remaining power. When n1W1 < W ≤ n1W2, the unit controller issues n1 operating state switching commands to the energy storage converters, and allocates them to the energy storage converters according to the combination of the optimal operating power value W1 and the relatively optimal operating power value W2. The last energy storage converter is allocated the remaining power.

2. The multi-stage power control method for the AC / DC integrated energy storage unit according to claim 1, characterized in that, When W > n1W2, the unit controller sends n1 operating state switching commands to the energy storage converter, and allocates power to each energy storage converter as needed according to the power balance distribution principle, so that it enters the balanced power state.

3. The multi-stage power control method for the AC / DC integrated energy storage unit according to claim 1, characterized in that, Based on the port position of the energy storage converter connected to the unit controller, the unit controller assigns a fixed number 1 to n to the energy storage converter.

4. The multi-stage power control method for the AC / DC integrated energy storage unit according to claim 3, characterized in that, When W≤n1W1, according to the principle of prioritizing the allocation of the optimal operating power value W1, the energy storage converters that have switched to the operating state are allocated W1 power in sequence according to their number size, so that they can enter the optimal operating power state.

5. The multi-stage power control method for the AC / DC integrated energy storage unit according to claim 3, characterized in that, When n1W1<W≤n1W2, the energy storage converter is allocated according to the combination of the optimal operating power value W1 and the relatively optimal operating power value W2, and the allocation is adaptive according to the size of the energy storage converter number, so that the energy storage converter enters the optimal operating power state or the relatively optimal operating power state.

6. A multi-stage power control system for an AC / DC integrated energy storage unit, characterized in that, include: A unit controller and n energy storage converters, each of the energy storage converters being communicatively connected to the unit controller, where n is a non-zero positive integer; The multi-level power control system of the AC / DC integrated energy storage unit also includes: The setting module allows the unit controller to set the optimal operating power value W1 and the suboptimal operating power value W2 for a single energy storage converter. The comparison module, upon receiving a power command W, compares the power command W with the total optimal operating power value n1W1 and the total relatively optimal operating power value n1W2 of the energy storage converters in a normal, fault-free state, where n1 is a non-zero positive integer less than or equal to n, and at least n1 of the n energy storage converters are in a normal, fault-free state. When W ≤ n1W1, the unit controller calculates the number n2 of energy storage converters that need to be switched to operating status based on the principle that the operating power value of a single energy storage converter is less than or equal to W1. For positive integers less than or equal to n1, n2 operating state switching commands are issued to the energy storage converters. Following the principle of prioritizing the allocation of the optimal operating power value W1, W1 power is sequentially allocated to the energy storage converters that have switched to the operating state, with the last energy storage converter receiving the remaining power. When n1W1 < W ≤ n1W2, the unit controller issues n1 operating state switching commands to the energy storage converters and allocates them according to a combination of the optimal operating power value W1 and a relatively optimal operating power value W2, with the last energy storage converter receiving the remaining power. The allocation module calculates the number of energy storage converters that need to enter the operating state based on the comparison results, as well as the power allocated to each energy storage converter entering the operating state. The unit controller sends a state switching signal and power value to each of the energy storage converters. After receiving and executing the instruction, each energy storage converter sends its standby / operating state and real-time power value to the unit controller. After receiving the information, the unit controller compares it with the state switching signal and power value sent by the unit controller to ensure that the instruction is executed correctly.

7. A multi-stage power control system for an AC / DC integrated energy storage unit according to claim 6, characterized in that, When the configured energy storage system is small in capacity, the multi-level power control system of the AC / DC integrated energy storage unit includes a unit controller, a coordination controller and n energy storage converters. The coordination controller is connected to the unit controller and controls the unit controller. Each of the energy storage converters is communicatively connected to the unit controller, and n is a non-zero positive integer.

8. A multi-stage power control system for an AC / DC integrated energy storage unit according to claim 6, characterized in that, When the configured energy storage system is small in capacity, the multi-level power control system of the AC / DC integrated energy storage unit includes a coordinating controller and n energy storage converters. Each of the energy storage converters is communicatively connected to the coordinating controller, and n is a non-zero positive integer.

9. A multi-stage power control system for an AC / DC integrated energy storage unit according to claim 6, characterized in that, When the configured energy storage system has a large capacity, the multi-level power control system of the AC / DC integrated energy storage unit includes multiple unit controllers, a coordination controller, and n energy storage converters. The multiple unit controllers and the coordination controller are connected by optical fiber to form a ring network communication. The coordination controller controls the unit controllers, and each of the energy storage converters is communicatively connected to the unit controller. n is a non-zero positive integer.

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