Control method of energy storage system, converter, energy storage system, and device

Abstract

This application discloses a control method, converter, energy storage system, and device for an energy storage system. The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a bus, and the energy storage unit can supply power to or absorb energy from the load unit through the bus. The control method of the energy storage system includes: determining a target voltage zone from multiple voltage zones based on a bus voltage signal, wherein the multiple voltage zones are divided based on a bus limiting voltage; and controlling the energy storage unit to supply power to or absorb energy from the load unit based on the target voltage zone, the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit. The method of this application can accurately partition the voltage control domain by dividing it into bus limiting voltage zones, accurately identify operating conditions, and improve the control effect of power supply or energy absorption through coordinated control of various units, thereby achieving stable operation under multiple operating conditions.

Description

Technical Field

[0001] This invention relates to the field of DC microgrid control, and more particularly to a control method, converter, energy storage system, and device for an energy storage system. Background Technology

[0002] A DC microgrid is a small-scale power system that effectively integrates distributed energy resources, energy storage systems, and loads. It is characterized by high efficiency and stability, and is therefore widely used in various fields. When supplying power to a system based on a DC microgrid, it is necessary to meet the overall requirements of the system under various operating conditions.

[0003] Existing technologies mainly rely on DC microgrids, which typically only consider the working state of the energy storage batteries within the microgrid for power supply or other functional control, without taking into account the overall operating state of the system. As a result, the power supply or other functional control is ineffective and cannot meet the stable operation requirements of the system under multiple operating conditions. Summary of the Invention

[0004] In view of the above problems, this application provides a control method, converter, energy storage system and device for an energy storage system, which can accurately partition the voltage control domain by dividing the bus limit voltage, accurately identify the operating conditions, and improve the control effect of power supply or energy consumption through the coordinated control of various units, so as to achieve stable operation under multiple operating conditions.

[0005] In a first aspect, this application provides a control method for an energy storage system. The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a bus, and the energy storage unit can supply power to or absorb energy from the load unit through the bus. The method includes: determining a target voltage zone from multiple voltage zones based on a bus voltage signal, wherein the multiple voltage zones are divided based on a bus limiting voltage; and controlling the energy storage unit to supply power to or absorb energy from the load unit based on the target voltage zone, the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit.

[0006] In the technical solution of this application embodiment, multiple voltage zones are divided based on the bus limit voltage, and a target voltage zone is determined from the multiple voltage zones based on the bus voltage signal. Then, according to the target voltage zone, based on the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit, the energy storage unit is controlled to supply power or absorb energy to the load unit. This can accurately partition the voltage control domain by dividing the bus limit voltage, accurately identify the operating conditions, and improve the control effect of power supply or absorption through the coordinated control of various units, thereby achieving stable operation under multiple operating conditions.

[0007] In some embodiments, based on the target voltage zone, and based on the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit, controlling the energy storage unit to supply power or absorb energy from the load unit includes: determining a target input control signal for the load unit based on the target voltage zone, and based on the voltage signal of the energy storage unit and the bus voltage signal; determining a target control result for the load unit based on the target voltage zone and the output power of the power generation unit; and controlling the energy storage unit to supply power or absorb energy from the load unit based on the target input control signal and the target control result.

[0008] In the technical solution of this application embodiment, the target input control signal of the load unit is determined based on the voltage signal of the energy storage unit and the bus voltage signal according to the target voltage zone. The target control result of the load unit is determined based on the output power of the power generation unit. Then, based on the target input control signal and the target control result, the energy storage unit is controlled to supply power or absorb energy to the load unit. This enables adaptive control for different operating conditions, achieves precise power distribution, improves the control effect of power supply or absorption, and ensures balanced operation under multiple operating conditions.

[0009] In some embodiments, the bus voltage limit includes a lower voltage limit and a higher voltage limit, and the plurality of voltage zones include at least two of a first voltage zone, a second voltage zone, and a third voltage zone. The first voltage zone is determined by the lower voltage limit and a first voltage value, the second voltage zone is determined by the first voltage value and a second voltage value, and the third voltage zone is determined by the second voltage value and the higher voltage limit, wherein the first voltage value is greater than the lower voltage limit, the second voltage value is greater than the first voltage value, and the higher voltage limit is greater than the second voltage value.

[0010] In the technical solution of this application embodiment, a first voltage zone is determined by the lower limit of the bus voltage and a first voltage value, a second voltage zone is determined by the first voltage value and a second voltage value, and a third voltage zone is determined by the upper limit of the bus voltage and the second voltage value. In this way, by accurately dividing the bus voltage value, the voltage control domain is accurately divided, the operating conditions are accurately identified, and stable control under complex operating conditions is achieved.

[0011] In some embodiments, determining a target input control signal for a load unit based on the voltage signal of the energy storage unit and the bus voltage signal according to a target voltage zone includes: determining a first current reference value based on the voltage signal of the energy storage unit; determining a second current reference value based on the bus voltage signal; and determining the target input control signal for the load unit from the first current reference value, the second current reference value, and the current limit value of the energy storage unit according to the target voltage zone.

[0012] In the technical solution of this application embodiment, based on the target voltage zone, a first current reference value is determined based on the voltage signal of the energy storage unit, and a second current reference value is determined based on the bus voltage signal. The target input control signal of the load unit is determined from the first current reference value, the second current reference value and the current limit value of the energy storage unit. In this way, the operating conditions can be judged according to the system operating status, and coordinated and stable adaptive control can be performed under different operating conditions to improve the control effect of power supply or energy absorption of the load and ensure stable operation under complex operating conditions.

[0013] In some embodiments, the voltage signal of the energy storage unit includes the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit; determining the first current reference value based on the voltage signal of the energy storage unit includes: performing closed-loop control based on the signal difference between the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit to obtain the first current reference value.

[0014] In the technical solution of this application embodiment, the closed-loop control of the energy storage battery voltage loop is performed by calculating the signal difference between the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit, and a first current reference value is determined. Thus, the energy storage battery voltage can be accurately adjusted through feedback control, adapting to various operating conditions and improving the stability and reliability of system operation.

[0015] In some embodiments, the bus voltage signal includes a bus voltage acquisition signal and a bus target voltage signal; determining a second current reference value based on the bus voltage signal includes: performing closed-loop control based on the signal difference between the bus voltage acquisition signal and the bus target voltage signal to obtain the second current reference value.

[0016] In the technical solution of this application embodiment, the bus voltage loop is closed-loop controlled by calculating the signal difference between the bus voltage acquisition signal and the bus target voltage signal, and a second current reference value is determined. In this way, the bus voltage is accurately controlled through feedback control, and the system operation stability is improved and the operating cost is reduced through the adaptive control strategy.

[0017] In some embodiments, the current limit value of the energy storage unit includes a lower current limit value and a higher current limit value; determining the target input control signal of the load unit from the first current reference value, the second current reference value, and the current limit value of the energy storage unit according to the target voltage zone includes: determining the upper current limit value as the target input control signal of the load unit when the target voltage zone is the first voltage zone and both the first current reference value and the second current reference value are greater than the upper current limit value; determining the second current reference value as the target input control signal of the load unit when the target voltage zone is the second voltage zone, the second current reference value is greater than the lower current limit value, and the second current reference value is less than both the first current reference value and the upper current limit value; and determining the lower current limit value as the target input control signal of the load unit when the target voltage zone is the third voltage zone and both the first current reference value and the second current reference value are less than the lower current limit value.

[0018] In the technical solution of this application embodiment, when in the first voltage zone, if both the first current reference value and the second current reference value are greater than the upper limit of the current of the energy storage unit, the upper limit of the current is used as the target input control signal of the load unit; when in the second voltage zone, if the second current reference value is greater than the lower limit of the current and less than the first current reference value and the upper limit of the current, the second current reference value is used as the target input control signal of the load unit; when in the third voltage zone, if both the first current reference value and the second current reference value are less than the lower limit of the current, the lower limit of the current is used as the target input control signal of the load unit. Through adaptive control of the three zones, it is ensured that the charging and discharging current of the energy storage unit does not exceed the safe operating range under multiple operating conditions, while meeting the system's requirements for bus voltage stability. By acquiring the target voltage signal of the energy storage unit and the target voltage signal of the bus less frequently, the response frequency of system control is reduced, enabling flexible and smooth switching of control modes. Power balancing and stable system operation are achieved under slow communication conditions, improving system operating efficiency.

[0019] In some embodiments, determining the target control result of the load unit based on the output power of the generator unit according to the target voltage zone includes: determining the required power of the load unit according to the target voltage zone; and determining the target control result of the load unit based on the required power of the load unit and the output power of the generator unit.

[0020] In the technical solution of this application embodiment, different voltage zones have different load demands, and the corresponding power allocation control strategies are also different. Based on the target voltage zone, the required power of the load unit is determined. Then, based on the required power of the load unit and the output power of the generator unit, the target control result of the load unit is determined, thereby performing adaptive control under multiple operating conditions. This ensures that the target control result of the load unit under different operating conditions can meet the load demand and balance the output power of the generator unit, achieving precise power allocation and stable system operation, and improving the control effect of power supply or energy absorption.

[0021] In some embodiments, determining the required power of a load unit based on a target voltage partition includes: determining the required power of the load unit as a first required power when the target voltage partition is a first voltage partition; determining the required power of the load unit as a second required power when the target voltage partition is a second voltage partition, wherein the second required power is less than or equal to the first required power; and determining the required power of the load unit as a third required power when the target voltage partition is a third voltage partition, wherein the third required power is less than or equal to the second required power.

[0022] In the technical solution of this application embodiment, the corresponding power demand of the load unit is determined according to different voltage zones. When in the first voltage zone, the power demand of the load unit is determined as the first power demand; when in the second voltage zone, the power demand of the load unit is determined as the second power demand; and when in the third voltage zone, the power demand of the load unit is determined as the third power demand. Through zone control, complex operating conditions are effectively addressed, the power demand of the load under different voltage zones is met, power allocation is optimized, and the stability and economy of system operation are ensured.

[0023] In some embodiments, determining the target control result of the load unit based on the load unit's required power and the generator unit's output power includes: when the target voltage zone is a first voltage zone, determining the maximum output power of the energy storage unit as the target control result based on the first required power, the generator unit's output power, and the load unit's limited power, wherein the load unit's limited power is associated with the maximum operating voltage of the first voltage zone; when the target voltage zone is a second voltage zone, determining the target control result based on the second required power and the generator unit's maximum output power, using the bus target voltage signal; and when the target voltage zone is a third voltage zone, determining the maximum absorbed power of the load unit as the target control result based on the third required power and the generator unit's output power.

[0024] In the technical solution of this application embodiment, when in the first voltage zone, based on the first demand power, the output power of the power generation unit, and the limited power of the load unit, the maximum output power of the energy storage unit is determined as the target control result. By limiting the load power, the output power of the energy storage unit is optimized to ensure the power balance of the system's normal operation. When in the second voltage zone, based on the second demand power and the maximum output power of the power generation unit, the target control result is determined as the target bus voltage signal. The bus voltage is stabilized by adjusting the output power of the energy storage unit. When in the third voltage zone, based on the third demand power and the output power of the power generation unit, the target control result is determined as the maximum absorbed power of the load unit. The bus voltage is stabilized by controlling the maximum absorbed power of the load unit. Through the distributed control of the three zones, complex and ever-changing operating conditions can be dealt with. The control method is simple and can effectively ensure the stable operation of the system and improve the system's operating efficiency.

[0025] On the other hand, this application provides a converter for an energy storage system. The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a bus, and the energy storage unit can supply power to the load unit or absorb energy through the bus. The converter is connected to the energy storage unit and the bus, and the converter can perform the method of any of the above embodiments.

[0026] On the other hand, this application provides an energy storage device, which includes an energy storage unit and a converter according to the above embodiments.

[0027] On the other hand, this application provides an energy storage system, which includes a power generation unit, an energy storage unit, a load unit, and a converter according to the above embodiments.

[0028] On the other hand, this application provides a control device for an energy storage system. The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a bus, and the energy storage unit can supply power to or absorb energy from the load unit through the bus. The device includes: a determination module, used to determine a target voltage zone from multiple voltage zones based on a bus voltage signal, wherein the multiple voltage zones are divided based on a bus limiting voltage; and a control module, used to control the energy storage unit to supply power to or absorb energy from the load unit based on the target voltage zone, the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit.

[0029] On the other hand, this application provides an electronic device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the method of any of the above embodiments.

[0030] On the other hand, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method of any of the above embodiments.

[0031] On the other hand, this application provides a computer program product, including a computer program, which, when executed by a processor, implements a method for any of the above-described embodiments.

[0032] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0034] Figure 1 A flowchart of the control method of the energy storage system according to an embodiment of this application is shown;

[0035] Figure 2 A schematic diagram of a ship DC power supply system according to an embodiment of this application is shown;

[0036] Figure 3 A control logic block diagram of an embodiment of this application is shown;

[0037] Figure 4 A schematic diagram of bus control domain division according to an embodiment of this application is shown;

[0038] Figure 5 A schematic diagram of the power tiered limit domain control mode according to an embodiment of this application is shown;

[0039] Figure 6 A schematic diagram of the autonomous domain control mode of energy storage power according to an embodiment of this application is shown;

[0040] Figure 7 A schematic diagram of the power generation energy absorption domain mode according to an embodiment of this application is shown;

[0041] Figure 8 A schematic diagram of an energy storage system according to an embodiment of this application is shown;

[0042] Figure 9 A block diagram of the control device of an energy storage system according to an embodiment of this application is shown;

[0043] Figure 10 A schematic diagram of an electronic device according to an embodiment of this application is shown. Detailed Implementation

[0044] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0046] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0047] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0048] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0049] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0050] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 the embodiments of this application and simplifying the description, and are not intended to 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 the embodiments of this application.

[0051] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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 communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0052] A DC microgrid is a small-scale power system that effectively integrates distributed energy resources, energy storage systems, and loads. It is characterized by high efficiency and stability, and is therefore widely used in various fields. When supplying power to a system based on a DC microgrid, it is necessary to meet the overall requirements of the system under various operating conditions.

[0053] Existing technologies mainly rely on DC microgrids, which typically only consider the working state of the energy storage batteries within the microgrid for power supply or other functional control, without taking into account the overall operating state of the system. This results in poor control of power supply or energy consumption, failing to meet the stable operation requirements of the system under multiple operating conditions.

[0054] A hierarchical operation control method for DC microgrid energy storage batteries based on state of charge (SOC) is proposed. The DC microgrid provides five operating modes for the energy storage batteries to control their hierarchical operation: constant power charging mode, droop charging mode, standby mode, droop discharging mode, and constant power discharging mode. In droop charging, standby, and droop discharging modes, the output power and operating voltage range of each energy storage battery are dynamically adjusted based on its own SOC. The batteries are put into or taken out of operation according to the voltage value at their respective converter output ports and their respective operating voltage ranges. This fully utilizes the capabilities of all energy storage batteries, maximizing the maintenance of the bus voltage within a reasonable range and ensuring stable operation of the microgrid system. However, controlling only the energy storage batteries is insufficient to meet the overall system requirements and cannot achieve stable operation under multiple operating conditions. Furthermore, communication delays exist between the controllers of the various bidirectional converters, making rapid communication difficult and costly to implement.

[0055] In view of this, this application proposes a control method for an energy storage system, which can accurately partition the voltage control domain by dividing the bus limit voltage, accurately identify the operating conditions, and improve the control effect of power supply or energy consumption through the coordinated control of various units, so as to achieve stable operation under multiple operating conditions.

[0056] In the technical solution of this application embodiment, multiple voltage zones are divided based on the bus limit voltage, and a target voltage zone is determined from the multiple voltage zones based on the bus voltage signal. Then, according to the target voltage zone, based on the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit, the energy storage unit is controlled to supply power or absorb energy to the load unit. This can accurately partition the voltage control domain by dividing the bus limit voltage, accurately identify the operating conditions, and improve the control effect of power supply or absorption through the coordinated control of various units, thereby achieving stable operation under multiple operating conditions.

[0057] Figure 1 A flowchart of the control method for an energy storage system according to an embodiment of this application is shown.

[0058] like Figure 1 As shown, the energy storage system control method provided in this application includes an energy storage microgrid (energy storage micronetwork) and a ship DC power supply system. The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a bus, and the energy storage unit can supply power to or absorb energy from the load unit through the bus. Method 100 includes steps S110 to S120.

[0059] Step S110: Based on the bus voltage signal, determine the target voltage zone from multiple voltage zones, wherein the multiple voltage zones are divided based on the bus limit voltage.

[0060] For example, multiple voltage zones are divided based on the bus limit voltage for precise domain classification. The bus limit voltage may include, for example, a fixed upper voltage limit and a fixed lower voltage limit. The multiple voltage zones may be control domains for different control modes. Based on the pre-divided voltage zones and the bus voltage signal under operating conditions, a target voltage zone is determined from the multiple voltage zones for corresponding power supply control or energy absorption control.

[0061] Step S120: Based on the target voltage zone, and using the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit, control the energy storage unit to supply power to the load unit or absorb energy.

[0062] For example, the control domain (voltage zone) where the bus voltage (bus voltage signal) is located is monitored in real time. Based on the current target voltage zone, and considering the voltage signals of the energy storage units, the bus voltage signal, and the output power of the generator units under operating conditions, the system controls the energy storage units to supply power to or absorb energy from the load units. This ensures that the entire system can achieve stable operation under different operating conditions through the coordinated control of each unit. The energy storage unit can be, for example, an energy storage battery; the generator unit can be, for example, a generator; and the load unit can be, for example, a motor. Here, energy absorption indicates that the energy storage unit can self-charge via the bus.

[0063] In the technical solution of this application embodiment, multiple voltage zones are divided based on the bus limit voltage, and a target voltage zone is determined from the multiple voltage zones based on the bus voltage signal. Then, according to the target voltage zone, based on the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit, the energy storage unit is controlled to supply power or absorb energy to the load unit. This can accurately partition the voltage control domain by dividing the bus limit voltage, accurately identify the operating conditions, and improve the control effect of power supply or absorption through the coordinated control of various units, thereby achieving stable operation under multiple operating conditions.

[0064] In one example, the control method for the energy storage system can be applied to a ship's DC power supply system including a converter. This method can be applied to the converter, which can be a DC-DC converter with a controller. The converter is primarily capable of performing dual-loop voltage and current control based on the voltage signals of the energy storage batteries and the bus voltage signal under the ship's operating conditions, ensuring stable operation of the system under multiple operating conditions. Besides this, the system can also have other forms, which are discussed below. Figure 2 Detailed introduction.

[0065] Figure 2 A schematic diagram of a ship DC power supply system according to an embodiment of this application is shown.

[0066] like Figure 2As shown, the ship's DC power supply system 200 includes at least a power generation unit 21 (generator), an energy storage unit 22 (energy storage battery), a propulsion motor 23 on the load unit side, a DC bus 24, a DC-DC converter 25 (DC converter, the method is applied to the converter) on the energy storage unit 22 side, an AC-DC converter 26 on the power generation unit side, and a DC-AC converter 27 on the propulsion motor 23 side.

[0067] For example, there can be multiple energy storage units 22 (energy storage batteries), each energy storage unit 22 is connected to a DC-DC converter 25, and supplies power to the propulsion motor 23 on the load unit side through DC bus 24 (bus) under the control of DC-DC converter 25; the power generation unit 21 is connected to AC-DC converter 26, and supplies power to the propulsion motor 23 through DC bus 24 under the control of AC-DC converter 26; the propulsion motor 23 is connected to DC-AC converter 27 (as a grid-connected control converter), and can absorb power and operate at a given speed or torque under the action of the output power of energy storage unit 22 and power generation unit 21, as well as under the propulsion and control of DC-AC converter 27.

[0068] This involves precisely dividing the bus voltage and pre-classifying the control domain, i.e., dividing it into multiple voltage zones (see below). Figure 4 The system independently monitors the control domain of the bus voltage in real time through each energy storage unit converter (DC converter), determines the control target of the converters connected to the power generation unit 21, energy storage unit 22 and propulsion motor 23 under actual operating conditions, and the controllers between the converters do not interfere with each other, perform distributed control, and work together to ensure the stable operation of the system under multiple operating conditions.

[0069] Next, we will introduce an example of how the controller in the DC-DC converter 25 performs multi-level control (using voltage and current dual-loop control) based on the method of this application to achieve stable operation of the system under multiple operating conditions.

[0070] Figure 3 A control logic block diagram of an embodiment of this application is shown.

[0071] For example, such as Figure 3 As shown, the control logic may include the following four parts: first sampling domain logic C1, first closed-loop calculation logic C2, first comparison and value acquisition logic C3, and second closed-loop calculation logic C4. Figure 3 In the middle, ν bus_ref ν is the reference value for the bus voltage. out_ref ν is the target voltage of the energy storage unit. bus The bus voltage, ν outThe battery voltage value is obtained from external sampling. A PI (proportional-integral) controller is a feedback controller widely used in DC microgrids. lim The current limit value for power limiting of energy storage units, I l This is the measured value of the actual output current of the busbar. The control logic of each part is explained in detail below.

[0072] First, combined Figure 4 This describes an example of dividing multiple voltage zones based on bus limit voltage.

[0073] Figure 4 A schematic diagram of the bus control domain division according to an embodiment of this application is shown.

[0074] For example, such as Figure 4 As shown, the vertical axis represents the bus voltage value. The first sampling domain logic C1 divides multiple voltage zones based on the bus limit voltage. The bus limit voltage includes a lower voltage limit and a higher voltage limit. The multiple voltage zones include at least two of the first voltage zone, the second voltage zone, and the third voltage zone. The first voltage zone is determined by the lower voltage limit and the first voltage value. The second voltage zone is determined by the first voltage value and the second voltage value. The third voltage zone is determined by the second voltage value and the upper voltage limit. The first voltage value is greater than the lower voltage limit, the second voltage value is greater than the first voltage value, and the upper voltage limit is greater than the second voltage value.

[0075] Specifically, refer to Figure 3 and Figure 4 According to the lower limit value M of the bus voltage signal bus min and upper voltage limit M bus max, the signal range M bus min to M bus The voltage levels between M and M can be divided into three domains from low to high: the power grading constraint domain S1 (first voltage zone), the energy storage voltage autonomous domain S2 (second voltage zone), and the power generation energy absorption domain S3 (third voltage zone). The first and second voltage values ​​are the bus operating voltages, respectively. The bus voltage is collected by sampling the bus voltage M. bus Signal, and according to M bus The control domain of the system is predefined and then sent to the converters corresponding to each energy storage unit. The converters then adjust the control domains based on the bus voltage M. bus The signal determines which control region it falls into, thereby accurately partitioning the voltage control domain.

[0076] In the technical solution of this application embodiment, a first voltage zone is determined by the lower limit of the bus voltage and a first voltage value, a second voltage zone is determined by the first voltage value and a second voltage value, and a third voltage zone is determined by the upper limit of the bus voltage and the second voltage value. In this way, by accurately dividing the bus voltage value, the voltage control domain is accurately divided, the operating conditions are accurately identified, and stable control under complex operating conditions is achieved.

[0077] For example, the target input control signal of the load unit is then determined based on the voltage signal of the energy storage unit and the bus voltage signal, according to the target voltage zone. For instance, a first current reference value is first determined based on the voltage signal of the energy storage unit, and a second current reference value is determined based on the bus voltage signal; then the target input control signal of the load unit is determined from the first current reference value, the second current reference value, and the current limit value of the energy storage unit.

[0078] In the technical solution of this application embodiment, based on the target voltage zone, a first current reference value is determined based on the voltage signal of the energy storage unit, and a second current reference value is determined based on the bus voltage signal. The target input control signal of the load unit is determined from the first current reference value, the second current reference value and the current limit value of the energy storage unit. In this way, the operating conditions can be judged according to the system operating status, and coordinated and stable adaptive control can be performed under different operating conditions to improve the control effect of power supply or energy absorption of the load and ensure stable operation under complex operating conditions.

[0079] The following combination Figure 3 Describe in detail how to determine the first current reference value and the second current reference value.

[0080] For example, continue to refer to Figure 3 The voltage signal of the energy storage unit includes the voltage acquisition signal M of the energy storage unit. bat (corresponding to the battery voltage value ν obtained from external sampling) out and the target voltage signal U of the energy storage unit bat_ref (Target voltage ν of the corresponding energy storage unit) out_ref Based on the voltage signal of the energy storage unit, the first current reference value is determined through the first closed-loop calculation logic C2. For example, the first current reference value can be obtained by performing closed-loop control based on the signal difference between the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit.

[0081] Specifically, the battery voltage detection signal M obtained from external sampling bat (Voltage acquisition signal of energy storage unit) and energy storage target voltage U bat_ref The difference is calculated, and the result is used for the closed-loop calculation of the voltage loop of each energy storage unit converter. The output result is used as the output I of the internal voltage loop of each energy storage unit converter. ref1(First current reference value) to achieve closed-loop control of the energy storage unit voltage loop.

[0082] In the technical solution of this application embodiment, the closed-loop control of the energy storage battery voltage loop is performed by calculating the signal difference between the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit, and a first current reference value is determined. Thus, the energy storage battery voltage can be accurately adjusted through feedback control, adapting to various operating conditions and improving the stability and reliability of system operation.

[0083] For example, continue to refer to Figure 3 The bus voltage signal includes the bus voltage acquisition signal M. bus (corresponding bus voltage ν) bus ) and bus target voltage signal U bus_ref (Reference value of bus voltage ν) bus_ref Based on the bus voltage signal, the second current reference value is determined through the first closed-loop calculation logic C2. For example, the second current reference value can be obtained by performing closed-loop control based on the signal difference between the bus voltage acquisition signal and the bus target voltage signal.

[0084] Specifically, the DC-DC converter (in the energy storage battery) performs closed-loop calculations of the bus voltage loop, converting the bus voltage signal M... bus (Bus voltage acquisition signal) and the reference value U of the bus voltage bus_ref The difference between the (bus target voltage signal) and the output result is used as the output I of the bus voltage loop. ref2 (Second current reference value) to achieve closed-loop control of the bus voltage loop.

[0085] In the technical solution of this application embodiment, the bus voltage loop is closed-loop controlled by calculating the signal difference between the bus voltage acquisition signal and the bus target voltage signal, and a second current reference value is determined. In this way, the bus voltage is accurately controlled through feedback control, and the system operation stability is improved and the operating cost is reduced through the adaptive control strategy.

[0086] Based on the first current reference value and the second current reference value, the target input control signal of the load unit under the current operating condition can be determined according to the voltage zone, so that the energy storage unit supplies power to the load unit under the control of the DC converter, thereby ensuring the stable operation of the system under the current operating condition. The following is a detailed explanation.

[0087] For example, based on the target voltage zone, the energy storage unit is controlled to supply power to the load unit based on the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit. For example, the target input control signal of the load unit is first determined based on the target voltage zone, the voltage signal of the energy storage unit, and the bus voltage signal.

[0088] Specifically, please refer to Figure 3 Based on the target voltage partition, the first comparison and value retrieval logic C3 is used to determine the first current reference value, the second current reference value, and the current limit value of the energy storage unit (corresponding to the current limit value I for power limiting of the energy storage unit). lim The target input control signal of the load unit is determined in the process.

[0089] First, based on the first sampling domain logic C1, determine the control domain (target voltage zone) in which the system resides, and design the system's power limits. The current limit value of the energy storage unit includes the upper current limit value I under the power limit value. lim+ and current lower limit value I lim- Set the upper limit of current I lim+ Current lower limit value I lim- And the result of the first closed-loop calculation logic C2 (output I of the voltage loop inside the energy storage unit). ref1 Output I of the bus voltage loop ref2 The smaller value is passed to the first comparison and value retrieval logic C3 for confirmation. Based on the voltage loop output (energy storage unit voltage loop and bus voltage loop), the appropriate control quantity is selected from the voltage loop output value and current limit value as the reference value for the current loop, i.e., the target input control signal I of the load unit. ref Target input control signal I ref It satisfies the following formula (1):

[0090] I ref =max(min(I ref1 ,I ref2 ,I lim +),I im- (1)

[0091] Among them, I ref1 I is the first reference current value. ref2 I is the second reference current value. lim+ I represents the upper limit of the current of the energy storage unit. lim- This is the lower limit of the current for the energy storage unit.

[0092] In the technical solution of this application embodiment, based on the target voltage zone, a first current reference value is determined based on the voltage signal of the energy storage unit, and a second current reference value is determined based on the bus voltage signal. The target input control signal of the load unit is determined from the first current reference value, the second current reference value and the current limit value of the energy storage unit. In this way, the operating conditions can be judged according to the system operating status, and coordinated and stable adaptive control can be performed under different operating conditions to improve the control effect of power supply or energy absorption of the load and ensure stable operation under complex operating conditions.

[0093] For example, the output target input control signal I is obtained. ref Then, based on the target input control signal I ref The energy storage unit can be controlled to supply power to the load unit, specifically based on the target input control signal I. ref The final control signal is obtained, and the energy storage unit is controlled to supply power to the load unit based on the final control signal.

[0094] Continue to refer to Figure 3 The second closed-loop calculation logic C4 takes the smaller output target from the first comparison and value taking logic C3 and inputs it into the control signal I. ref As a grid-connected control converter ( Figure 2 The current loop input of the converter (connected to the motor) is calculated through current closed-loop control, i.e., the reference value I of the current loop is obtained. ref The measured current I of the actual output of the busbar l After differential calculation, PI regulation is performed to obtain the final control signal of the DC-DC converter of the energy storage unit. The final control signal can be, for example, the duty cycle signal.

[0095] Power supply closed-loop control of the load unit requires a target input control signal I. ref And the target control result. When controlling the output power supply signal of the DC-DC converter on the load unit side, the target control result is used as the control objective, and the target input control signal I is used. ref Closed-loop control is performed using the input signal I. The above describes how to obtain the target input control signal I. ref Next, we will describe how to obtain the target control results.

[0096] Specifically, based on the target voltage zone and the output power of the power generation unit, the target control result of the load unit is determined.

[0097] Specifically, based on the target voltage zone and the output power of the generator unit, the target control result of the load unit is determined. For example, firstly, the required power of the load unit is determined based on the target voltage zone; then, based on the required power of the load unit and the output power of the generator unit, the target control result of the load unit is determined.

[0098] For example, the power demand of a load unit differs depending on the voltage zone. The power demand of a load unit can be determined, for example, by the power demand of the bus load. The output power of the generator unit can be, for example, the power output by the generator to the propulsion motor (load unit) through the DC bus under the control of the corresponding AC-DC converter under the current operating conditions. The target control result of the load unit can be, for example, the specific control objective of the DC converter to ensure stable operation of the system based on the reference value of the current loop (the target input control signal of the load unit).

[0099] For example, finally, based on the target voltage zone, the energy storage unit is controlled to supply power to the load unit according to the target input control signal and the target control result, so that the system can operate stably under multiple operating conditions.

[0100] In the technical solution of this application embodiment, different voltage zones have different load demands, and the corresponding power allocation control strategies are also different. Based on the target voltage zone, the required power of the load unit is determined. Then, based on the required power of the load unit and the output power of the generator unit, the target control result of the load unit is determined, thereby performing adaptive control under multiple operating conditions. This ensures that the target control result of the load unit under different operating conditions can meet the load demand and balance the output power of the generator unit, achieving precise power allocation and stable system operation, and improving the control effect of power supply or energy absorption.

[0101] In the technical solution of this application embodiment, the target input control signal of the load unit is determined based on the voltage signal of the energy storage unit and the bus voltage signal according to the target voltage zone. The target control result of the load unit is determined based on the output power of the power generation unit. Then, based on the target input control signal and the target control result, the energy storage unit is controlled to supply power to the load unit. This enables adaptive control for different operating conditions, achieves precise power distribution, improves the control effect of power supply or energy absorption, and ensures balanced operation under multiple operating conditions.

[0102] In another example, when the voltage partitions are in the control domains of the power limiting domain S1, the energy storage voltage autonomous domain S2, and the power generation energy absorption domain S3, respectively, adaptive hierarchical control can be performed through different control modes to achieve stable operation of the system under multiple operating conditions and improve the control effect of power supply or energy absorption. The control logic of each voltage partition is explained separately below.

[0103] Figure 5 A schematic diagram of the power grading limit domain control mode according to an embodiment of this application is shown.

[0104] For example, such as Figure 5 As shown, Figure 5 Reference for the meaning of coordinates and definitions of each unit device Figure 2 and Figure 4 The current limit value of the energy storage unit includes a lower current limit value and a higher current limit value. Based on the target voltage zone, the target input control signal of the load unit is first determined from the first current reference value, the second current reference value, and the current limit value of the energy storage unit. For example, if the target voltage zone is the first voltage zone and both the first current reference value and the second current reference value are greater than the higher current limit value, the higher current limit value is determined to be the target input control signal of the load unit.

[0105] Specifically, refer to Figure 5 When the bus voltage meets the power grading constraint domain S1 (first voltage zone), the DC-DC converter controller of the energy storage unit first samples the bus voltage acquisition signal M. bus The energy storage unit is determined to be in the power classification restriction domain S1 based on the bus voltage acquisition signal.

[0106] The first closed-loop calculation logic C2 will use the externally sampled battery voltage detection signal M... bat (Voltage acquisition signal of energy storage unit) and energy storage target voltage U bat_ref By performing the difference operation, we obtain the output I of the internal voltage loop of the energy storage battery. ref1 (First current reference value); and the bus voltage signal M bus (Bus voltage acquisition signal) and the reference value U of the bus voltage bus_ref The difference between the (bus target voltage signal) and the output I of the energy storage battery bus voltage loop is obtained through closed-loop control. ref2 (Second current reference value).

[0107] Then, based on its power limitation class, the energy storage battery calculates the current limitation value I under its current power limitation value. lim Since it is in state S1, the voltage loop calculation result and the current limit value are processed through the first comparison logic C3. The comparison calculation result of the energy storage battery controller usually satisfies I. ref2 I ref1 >I lim+ Therefore, I lim+ As the current loop input (target input control signal) of the energy storage battery, it ensures the stable operation of the system under the current operating conditions.

[0108] In the technical solution of this application embodiment, when in the first voltage zone, if both the first current reference value and the second current reference value are greater than the upper limit value of the current of the energy storage unit, the upper limit value of the current is used as the target input control signal of the load unit to ensure that the charging and discharging current of the energy storage unit does not exceed the safe operating range under the operating conditions of the first voltage zone, while meeting the system's requirements for the stability of the bus voltage, so as to achieve balanced power distribution and stable system operation, and improve system operating efficiency.

[0109] Then, based on the target voltage zone, the required power of the load unit is determined. For example, if the target voltage zone is the first voltage zone, the required power of the load unit is determined to be the first required power.

[0110] For example, based on the power demand of the load unit and the output power of the power generation unit, the target control result of the load unit is determined. For instance, if the target voltage zone is a first voltage zone, the target control result is determined to be the maximum output power of the energy storage unit based on the first power demand, the output power of the power generation unit, and the power limitation of the load unit, wherein the power limitation of the load unit is associated with the maximum operating voltage of the first voltage zone.

[0111] Specifically, please refer to Figure 5 When the bus voltage meets the power grading restriction domain S1, the bus voltage value is at a low level. The detection judges that the bus load demand is high (the first demand power can be determined based on the bus load demand). The system identifies that it is currently in the power grading restriction domain S1. At this time, even if the power generation unit and the energy storage unit output at maximum power, they cannot meet the bus power demand.

[0112] Therefore, the system uses the bus voltage signal M bus Power limiting is applied at voltage level S1, limiting the load power to P. lim (The power limit of the load unit) is calculated based on the bus voltage value, and satisfies the inverse correlation and continuous change law shown in formula (2) with the bus voltage difference:

[0113]

[0114] Among them, P rated M is the rated power of the load. busS1 max is the maximum bus operating voltage (first voltage value) of the power grading limit domain S1. Figure 5 (the upper limit of the S1 region is indicated by the dashed line), M bus For bus voltage signal, M bus min is the lower limit of the bus voltage. Figure 5 (The lower limit dashed line part of region S1), where k is the power change rate adjustment coefficient.

[0115] Based on the load unit's power demand under the current operating conditions (first demand power), the current output power of the power generation unit, and the power limit on the load, the maximum output power of the energy storage unit (target control result of the first voltage zone) is used as the control target of the DC converter of the first voltage zone to ensure the stable operation of the system under the current operating conditions.

[0116] In the technical solution of this application embodiment, the required power of the load unit is determined according to different voltage zones. When in the first voltage zone, the required power of the load unit is determined as the first required power. Based on the first required power, the output power of the power generation unit, and the limited power of the load unit, the maximum output power of the energy storage unit is determined as the target control result. By limiting the load power, the output power of the energy storage unit is optimized, ensuring the power balance of the system's normal operation, effectively guaranteeing the stable operation of the system, and improving the system's operating efficiency.

[0117] Figure 6 A schematic diagram of the autonomous control mode of energy storage power according to an embodiment of this application is shown.

[0118] For example, such as Figure 6 As shown, Figure 6 Reference for the meaning of coordinates and definitions of each unit device Figure 2 and Figure 4 When the target voltage zone is the second voltage zone, the second current reference value is greater than the lower current limit, and the second current reference value is less than the first current reference value and the upper current limit, the second current reference value is determined to be the target input control signal of the load unit.

[0119] Specifically, refer to Figure 6 When the bus voltage meets the energy storage voltage autonomous region S2 (second voltage partition), the DC-DC converter controller of the energy storage unit first samples the bus voltage acquisition signal M. bus The energy storage unit is located in the energy storage voltage autonomous domain S2 based on the bus voltage acquisition signal.

[0120] The first closed-loop calculation logic C2 will use the externally sampled battery voltage detection signal M... bat (Voltage acquisition signal of energy storage unit) and energy storage target voltage U bat_ref By performing the difference operation, we obtain the output I of the internal voltage loop of the energy storage battery. ref1 (First current reference value); and the bus voltage signal M bus (Bus voltage acquisition signal) and the reference value U of the bus voltage bus_ref The difference between the (bus target voltage signal) and the output I of the energy storage battery bus voltage loop is obtained through closed-loop control. ref2 (Second current reference value).

[0121] Then, based on its power limitation class, the energy storage battery calculates the current limitation value I under its current power limitation value. lim Since we are in state S2, the voltage loop calculation results and current limit values ​​mentioned above are processed through the first comparison logic C3. If the comparison calculation results of the energy storage battery controller satisfy I... lim+ I ref1 >Iref2 >I lim- Then the output I of the battery bus voltage loop will be... ref2 As the current loop input of the load unit (target input control signal), it ensures the stable operation of the system under the current operating conditions.

[0122] In the technical solution of this application embodiment, when in the second voltage zone, if the second current reference value is greater than the lower current limit, and the second current reference value is less than the first current reference value and the upper current limit, the second current reference value is used as the target input control signal of the load unit to ensure that the charging and discharging current of the energy storage unit does not exceed the safe operating range under the operating conditions of the second voltage zone, while meeting the system's requirements for bus voltage stability, so as to achieve power balance distribution and stable system operation, and improve system operating efficiency.

[0123] Then, if the target voltage zone is the second voltage zone, the required power of the load unit is determined as the second required power, wherein the second required power is less than or equal to the first required power.

[0124] For example, when the target voltage zone is the second voltage zone, the target control result is determined based on the second demand power and the maximum output power of the power generation unit, with the target bus voltage signal as the target control result.

[0125] Specifically, please refer to Figure 6 When the bus voltage meets the autonomous region S2 of the energy storage voltage, the bus load demand is high (the second demand power can be determined based on the bus load demand). The bus power can be allocated to enable the generator to output maximum power. At the same time, the bus power is adjusted through the energy storage unit.

[0126] At this time, the converter controller of the energy storage unit uses the reference value U of the bus voltage. bus_ref (Bus target voltage signal) is used for bus voltage control, that is, the reference value U of the bus voltage. bus_ref (The target control result of the second voltage zone) serves as the control target for the DC converter. The converter of the power generation unit is based on the maximum power input P. gmax The control unit outputs power to the bus at maximum power, and the propulsion system converter (DC-AC converter) outputs propulsion power as needed to supply the propulsion motor (load unit) to work at a given speed or torque to ensure the stable operation of the system under the current operating conditions.

[0127] In the technical solution of this application embodiment, when in the second voltage zone, the required power of the load unit is determined as the second required power. Based on the second required power and the maximum output power of the power generation unit, the target control result is determined to be the target voltage signal of the bus. By adjusting the output power of the energy storage unit, the bus voltage is kept stable, which can effectively ensure the stable operation of the system and improve the system operating efficiency.

[0128] Figure 7 A schematic diagram of the power generation energy absorption domain mode according to an embodiment of this application is shown.

[0129] For example, such as Figure 7 As shown, Figure 7 Reference for the meaning of coordinates and definitions of each unit device Figure 2 and Figure 4 When the target voltage zone is the third voltage zone and both the first current reference value and the second current reference value are less than the lower current limit value, the lower current limit value is determined to be the target input control signal of the load unit.

[0130] Specifically, refer to Figure 7 When the bus voltage meets the power generation energy absorption domain S3 (third voltage zone), the DC converter controller of the energy storage unit first samples the bus voltage acquisition signal M. bus The energy storage unit is located in the power generation energy absorption domain S3 based on the bus voltage acquisition signal.

[0131] The first closed-loop calculation logic C2 will use the externally sampled battery voltage detection signal M... bat (Voltage acquisition signal of energy storage unit) and energy storage target voltage U bat_ref By performing the difference operation, we obtain the output I of the internal voltage loop of the energy storage battery. ref1 (First current reference value); and the bus voltage signal M bus (Bus voltage acquisition signal) and the reference value U of the bus voltage bus_ref The difference between the (bus target voltage signal) and the output I of the energy storage battery bus voltage loop is obtained through closed-loop control. ref2 (Second current reference value).

[0132] Then, based on its power limitation class, the energy storage battery calculates the current limitation value I under its current power limitation value. lim Since it is in state S3, the voltage loop calculation result and the current limit value mentioned above are passed through the first comparison and value retrieval logic C3. If the comparison calculation result of the energy storage battery controller satisfies I... lim- >I ref2 I ref1 Then, the maximum absorption current (lower current limit I) is used. lim- (The current loop input target control signal of the load unit) is used to ensure the stable operation of the system under the current operating conditions.

[0133] In the technical solution of this application embodiment, when in the first voltage zone, if both the first current reference value and the second current reference value are greater than the upper limit of the current of the energy storage unit, the upper limit of the current is used as the target input control signal of the load unit; when in the second voltage zone, if the second current reference value is greater than the lower limit of the current and less than the first current reference value and the upper limit of the current, the second current reference value is used as the target input control signal of the load unit; when in the third voltage zone, if both the first current reference value and the second current reference value are less than the lower limit of the current, the lower limit of the current is used as the target input control signal of the load unit. Through adaptive control of the three zones, it is ensured that the charging and discharging current of the energy storage unit does not exceed the safe operating range under multiple operating conditions, while meeting the system's requirements for bus voltage stability. By acquiring the target voltage signal of the energy storage unit and the target voltage signal of the bus less frequently, the response frequency of system control is reduced, enabling flexible and smooth switching of control modes. Power balancing and stable system operation are achieved under slow communication conditions, improving system operating efficiency.

[0134] Then, if the target voltage zone is the third voltage zone, the required power of the load unit is determined to be the third required power, wherein the third required power is less than or equal to the second required power.

[0135] Specifically, please refer to Figure 7 When the bus voltage meets the power generation energy absorption domain S3, the bus voltage is at a high level, and the bus load demand is low (the third demand power can be determined based on the bus load demand). At this time, the converter connected to the power generation unit controls the bus voltage (the power generation unit can adjust the output voltage according to the demand, thereby changing the bus voltage).

[0136] In the technical solution of this application embodiment, the corresponding power demand of the load unit is determined according to different voltage zones. When in the first voltage zone, the power demand of the load unit is determined as the first power demand; when in the second voltage zone, the power demand of the load unit is determined as the second power demand; and when in the third voltage zone, the power demand of the load unit is determined as the third power demand. Through zone control, complex operating conditions are effectively addressed, the power demand of the load under different voltage zones is met, power allocation is optimized, and the stability and economy of system operation are ensured.

[0137] For example, when the target voltage zone is the third voltage zone, the target control result is determined based on the third demand power and the output power of the power generation unit, with the maximum absorbed power of the load unit as the target control result.

[0138] Continue to refer to Figure 7The energy storage unit converter controls the energy storage unit to absorb power at the maximum power according to the maximum power absorbed by the load. That is, the maximum power absorbed by the load unit (the target control result of the third voltage zone) is used as the control target of the DC-AC converter. The propulsion system converter (DC-AC converter) outputs the maximum propulsion power to supply the propulsion motor (load unit) to work at the maximum speed and torque to ensure the stable operation of the system under the current working conditions.

[0139] In the technical solution of this application embodiment, when in the first voltage zone, based on the first demand power, the output power of the power generation unit, and the limited power of the load unit, the maximum output power of the energy storage unit is determined as the target control result. By limiting the load power, the output power of the energy storage unit is optimized to ensure the power balance of the system's normal operation. When in the second voltage zone, based on the second demand power and the maximum output power of the power generation unit, the target control result is determined as the target bus voltage signal. The bus voltage is stabilized by adjusting the output power of the energy storage unit. When in the third voltage zone, based on the third demand power and the output power of the power generation unit, the target control result is determined as the maximum absorbed power of the load unit. The bus voltage is stabilized by controlling the maximum absorbed power of the load unit. Through the distributed control of the three zones, complex and ever-changing operating conditions can be dealt with. The control method is simple and can effectively ensure the stable operation of the system and improve the system's operating efficiency.

[0140] This application provides a converter for an energy storage system. The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a bus, and the energy storage unit can supply power to the load unit or absorb energy through the bus. The converter is connected to the energy storage unit and the bus, and the converter can execute the method in any of the above embodiments.

[0141] This application provides an energy storage device, which includes an energy storage unit and a converter as described in the above embodiments.

[0142] Figure 8 A schematic diagram of an energy storage system according to an embodiment of this application is shown.

[0143] like Figure 8 As shown, this application provides an energy storage system. Please refer to [link / reference]. Figure 8 The energy storage system 800 includes a power generation unit 801, an energy storage unit 802, a load unit 803, and a converter 804 as described in the above embodiments.

[0144] Figure 9 A block diagram of the control device for an energy storage system according to an embodiment of this application is shown.

[0145] This application provides a control device 900 for an energy storage system. Please refer to [link / reference]. Figure 9 The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a bus, and the energy storage unit can supply power to or absorb energy from the load unit through a bus. The device 900 includes:

[0146] The determination module 910 is used to determine the target voltage zone from multiple voltage zones based on the bus voltage signal, wherein the multiple voltage zones are divided based on the bus limit voltage.

[0147] The control module 920 is used to control the energy storage unit to supply power or absorb energy from the load unit based on the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit, according to the target voltage zone.

[0148] For example, the control module 920 is further configured to: determine the target input control signal of the load unit based on the voltage signal of the energy storage unit and the bus voltage signal according to the target voltage zone; determine the target control result of the load unit based on the output power of the power generation unit according to the target voltage zone; and control the energy storage unit to supply power or absorb energy to the load unit based on the target input control signal and the target control result.

[0149] For example, the bus voltage limit includes a lower voltage limit and a higher voltage limit, and the multiple voltage zones include at least two of a first voltage zone, a second voltage zone, and a third voltage zone. The first voltage zone is determined by the lower voltage limit and a first voltage value, the second voltage zone is determined by the first voltage value and a second voltage value, and the third voltage zone is determined by the second voltage value and the higher voltage limit. The first voltage value is greater than the lower voltage limit, the second voltage value is greater than the first voltage value, and the higher voltage limit is greater than the second voltage value.

[0150] For example, based on the target voltage zone, the target input control signal of the load unit is determined based on the voltage signal of the energy storage unit and the bus voltage signal, including: determining a first current reference value based on the voltage signal of the energy storage unit; determining a second current reference value based on the bus voltage signal; and determining the target input control signal of the load unit from the first current reference value, the second current reference value and the current limit value of the energy storage unit according to the target voltage zone.

[0151] For example, the voltage signal of the energy storage unit includes the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit; determining the first current reference value based on the voltage signal of the energy storage unit includes: performing closed-loop control based on the signal difference between the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit to obtain the first current reference value.

[0152] For example, the bus voltage signal includes a bus voltage acquisition signal and a bus target voltage signal; determining a second current reference value based on the bus voltage signal includes: performing closed-loop control based on the signal difference between the bus voltage acquisition signal and the bus target voltage signal to obtain the second current reference value.

[0153] For example, the current limit value of the energy storage unit includes a lower current limit value and a higher current limit value; determining the target input control signal of the load unit from the first current reference value, the second current reference value, and the current limit value of the energy storage unit according to the target voltage zone includes: determining the upper current limit value as the target input control signal of the load unit when the target voltage zone is the first voltage zone and both the first current reference value and the second current reference value are greater than the upper current limit value; determining the second current reference value as the target input control signal of the load unit when the target voltage zone is the second voltage zone, the second current reference value is greater than the lower current limit value, and the second current reference value is less than both the first current reference value and the upper current limit value; and determining the lower current limit value as the target input control signal of the load unit when the target voltage zone is the third voltage zone and both the first current reference value and the second current reference value are less than the lower current limit value.

[0154] For example, determining the target control result of the load unit based on the output power of the generator unit according to the target voltage zone includes: determining the required power of the load unit according to the target voltage zone; and determining the target control result of the load unit based on the required power of the load unit and the output power of the generator unit.

[0155] For example, determining the required power of a load unit based on a target voltage zone includes: determining the required power of the load unit as a first required power when the target voltage zone is a first voltage zone; determining the required power of the load unit as a second required power when the target voltage zone is a second voltage zone, wherein the second required power is less than or equal to the first required power; and determining the required power of the load unit as a third required power when the target voltage zone is a third voltage zone, wherein the third required power is less than or equal to the second required power.

[0156] For example, determining the target control result of the load unit based on the load unit's required power and the generator unit's output power includes: when the target voltage zone is a first voltage zone, determining the maximum output power of the energy storage unit as the target control result based on the first required power, the generator unit's output power, and the load unit's limited power, wherein the load unit's limited power is associated with the maximum operating voltage of the first voltage zone; when the target voltage zone is a second voltage zone, determining the target control result based on the second required power and the generator unit's maximum output power, using the bus target voltage signal; and when the target voltage zone is a third voltage zone, determining the maximum absorbed power of the load unit as the target control result based on the third required power and the generator unit's output power.

[0157] It is understood that for a detailed description of the control device 900 of the energy storage system, please refer to the description of the control method of the energy storage system above.

[0158] Figure 10 A schematic diagram of an electronic device according to an embodiment of this application is shown.

[0159] This application provides an electronic device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the method in any of the above embodiments.

[0160] like Figure 10 As shown, for ease of understanding, an embodiment of this application illustrates a specific electronic device 1000.

[0161] Electronic device 1000 is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic device 1000 may also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the present disclosure described and / or claimed herein.

[0162] like Figure 10As shown, device 1000 includes a computing unit 1001, which can perform various appropriate actions and processes according to a computer program stored in read-only memory (ROM) 1002 or a computer program loaded from storage unit 1008 into random access memory (RAM) 1003. RAM 1003 may also store various programs and data required for the operation of electronic device 1000. The computing unit 1001, ROM 1002, and RAM 1003 are interconnected via bus 1004. Input / output (I / O) interface 1005 is also connected to bus 1004.

[0163] Multiple components in electronic device 1000 are connected to I / O interface 1005. These components include: input unit 1006, such as a keyboard or mouse; output unit 1007, such as various types of displays or speakers; storage unit 1008, such as a hard disk or optical disk; and communication unit 1009, such as a network interface card (NIC), modem, or wireless transceiver. Communication unit 1009 allows electronic device 1000 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0164] The computing unit 1001 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 1001 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The computing unit 1001 performs the various methods described above. For example, in some embodiments, any one or more of the methods described above can be implemented as a computer software program tangibly contained in a machine-readable medium, such as storage unit 1008. In some embodiments, part or all of the computer program can be loaded and / or installed on the electronic device 1000 via ROM 1002 and / or communication unit 1009. When the computer program is loaded into RAM 1003 and executed by the computing unit 1001, one or more steps of any one or more of the methods described above can be performed. Alternatively, in other embodiments, the computing unit 1001 can be configured to perform any one or more of the methods described above by any other suitable means (e.g., by means of firmware).

[0165] This application provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the method in any of the above embodiments.

[0166] This application provides a computer program product, including a computer program, which, when executed by a processor, implements the method of any of the above embodiments.

[0167] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequential list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this application, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). In addition, computer-readable media can even be paper or other suitable media on which programs can be printed, because programs can be obtained electronically, for example, by optically scanning paper or other media, followed by editing, interpreting or otherwise processing as necessary, and then stored in computer memory.

[0168] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0169] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not 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 or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A control method for an energy storage system, characterized in that, The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a busbar, and the energy storage unit can supply power to or absorb energy from the load unit through a busbar. The method includes: Based on the bus voltage signal, a target voltage zone is determined from multiple voltage zones, wherein the multiple voltage zones are divided based on the bus limit voltage; Based on the target voltage zone, the energy storage unit is controlled to supply power or absorb energy from the load unit, according to the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit.

2. The method according to claim 1, characterized in that, The step of controlling the energy storage unit to supply power or absorb energy from the load unit based on the target voltage zone, the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit includes: Based on the target voltage zone, and using the voltage signal of the energy storage unit and the bus voltage signal, the target input control signal of the load unit is determined. Based on the target voltage zone and the output power of the power generation unit, the target control result of the load unit is determined. Based on the target input control signal and the target control result, the energy storage unit is controlled to supply power to the load unit or absorb energy.

3. The method according to claim 1 or 2, characterized in that, The bus voltage limit includes a lower voltage limit and an upper voltage limit. The plurality of voltage zones include at least two of a first voltage zone, a second voltage zone, and a third voltage zone. The first voltage zone is determined by the lower voltage limit and a first voltage value. The second voltage zone is determined by the first voltage value and a second voltage value. The third voltage zone is determined by the second voltage value and the upper voltage limit. The first voltage value is greater than the lower voltage limit, the second voltage value is greater than the first voltage value, and the upper voltage limit is greater than the second voltage value.

4. The method according to claim 2, characterized in that, The step of determining the target input control signal of the load unit based on the target voltage zone, the voltage signal of the energy storage unit, and the bus voltage signal includes: Based on the voltage signal of the energy storage unit, a first current reference value is determined; Based on the bus voltage signal, a second current reference value is determined; Based on the target voltage zone, the target input control signal of the load unit is determined from the first current reference value, the second current reference value, and the current limit value of the energy storage unit.

5. The method according to claim 4, characterized in that, The voltage signal of the energy storage unit includes the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit; determining the first current reference value based on the voltage signal of the energy storage unit includes: Closed-loop control is performed based on the signal difference between the voltage acquisition signal of the energy storage unit and the target voltage signal of the energy storage unit to obtain the first current reference value.

6. The method according to claim 4 or 5, characterized in that, The bus voltage signal includes a bus voltage acquisition signal and a bus target voltage signal; determining the second current reference value based on the bus voltage signal includes: Closed-loop control is performed based on the signal difference between the bus voltage acquisition signal and the bus target voltage signal to obtain the second current reference value.

7. The method according to any one of claims 4-6, characterized in that, The current limit value of the energy storage unit includes a lower current limit value and a higher current limit value; based on the target voltage zone, the target input control signal of the load unit is determined from the first current reference value, the second current reference value, and the current limit value of the energy storage unit, including: When the target voltage zone is the first voltage zone and both the first current reference value and the second current reference value are greater than the upper limit value of the current, the upper limit value of the current is determined to be the target input control signal of the load unit; When the target voltage zone is the second voltage zone, the second current reference value is greater than the lower current limit, and the second current reference value is less than the first current reference value and the upper current limit, the second current reference value is determined to be the target input control signal of the load unit. When the target voltage zone is the third voltage zone and both the first current reference value and the second current reference value are less than the lower current limit value, the lower current limit value is determined to be the target input control signal of the load unit.

8. The method according to any one of claims 2, 4-7, characterized in that, The step of determining the target control result of the load unit based on the output power of the power generation unit according to the target voltage zone includes: The required power of the load unit is determined based on the target voltage zone. The target control result of the load unit is determined based on the power demand of the load unit and the output power of the power generation unit.

9. The method according to claim 8, characterized in that, Determining the required power of the load unit based on the target voltage zone includes: When the target voltage zone is the first voltage zone, the required power of the load unit is determined to be the first required power; When the target voltage zone is the second voltage zone, the required power of the load unit is determined to be the second required power, wherein the second required power is less than or equal to the first required power; When the target voltage zone is the third voltage zone, the required power of the load unit is determined to be the third required power, wherein the third required power is less than or equal to the second required power.

10. The method according to claim 9, characterized in that, The determination of the target control result for the load unit based on the load unit's power demand and the power generation unit's output includes: When the target voltage zone is the first voltage zone, based on the first demand power, the output power of the power generation unit and the limiting power of the load unit, the maximum output power of the energy storage unit is determined as the target control result, wherein the limiting power of the load unit is associated with the maximum operating voltage of the first voltage zone; When the target voltage zone is the second voltage zone, the target control result is determined based on the second demand power and the maximum output power of the power generation unit, with the bus target voltage signal as the target control result. When the target voltage zone is the third voltage zone, the target control result is determined based on the third demand power and the output power of the power generation unit, with the maximum absorbed power of the load unit as the target control result.

11. A converter for an energy storage system, characterized in that, The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a bus. The energy storage unit can supply power to the load unit or absorb energy through the bus. The converter is connected to the energy storage unit and the bus. The converter can perform the method according to any one of claims 1-10.

12. An energy storage device, characterized in that, The energy storage device includes an energy storage unit and a converter according to claim 11.

13. An energy storage system, characterized in that, The energy storage system includes a power generation unit, an energy storage unit, a load unit, and a converter according to claim 11.

14. A control device for an energy storage system, characterized in that, The energy storage system includes a power generation unit, an energy storage unit, and a load unit. The power generation unit can supply power to the load unit through a busbar, and the energy storage unit can supply power to or absorb energy from the load unit through a busbar. The device includes: The determination module is used to determine a target voltage zone from multiple voltage zones based on the bus voltage signal, wherein the multiple voltage zones are divided based on the bus limit voltage; The control module is used to control the energy storage unit to supply power or absorb energy to the load unit based on the target voltage zone, the voltage signal of the energy storage unit, the bus voltage signal, and the output power of the power generation unit.

15. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1-10.

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

17. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method according to any one of claims 1-10.

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