Flexible interconnection system of ac-dc multi-port, starting method and storage medium

Abstract

The application discloses an AC-DC multi-port flexible interconnection system, a starting method and a storage medium. The method comprises the following steps: acquiring the target port quantity in the system; determining the operation mode supported by the system according to the target port quantity, and obtaining a plurality of operation modes; acquiring the target use demand of a target object; the target object is a user of the system; selecting a target operation mode corresponding to the target use demand from the plurality of operation modes; starting the system according to the target operation mode, so that the system supplies power for the target load. By adopting the embodiment of the application, the safe starting of the AC-DC multi-port flexible interconnection system is realized.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to an AC / DC multi-port flexible interconnection system, a startup method, and a storage medium. Background Art

[0002] With the widespread application of renewable energy and the development of power systems, the traditional single-port power supply mode can no longer meet the needs of modern power systems.

[0003] Multi-port flexible interconnection systems can achieve flexible interconnection between multiple power sources and loads, improving power supply reliability and flexibility. However, how to achieve safe startup of multi-port flexible interconnection systems remains an urgent problem. Summary of the Invention

[0004] The embodiments of the present application provide an AC / DC multi-port flexible interconnection system, a startup method, and a storage medium, which achieve safe startup of the AC / DC multi-port flexible interconnection system.

[0005] In a first aspect, an embodiment of the present application provides an AC / DC multi-port flexible interconnection system, the system comprising: a target controller, a first AC power supply, a second AC power supply, a third AC power supply, a first voltage source converter, a second voltage source converter, a third voltage source converter, a DC transformer, and a target load, wherein:

[0006] The first AC power source is connected to a first end of the first voltage source converter, and the second end of the first voltage source converter is connected to a first end of the second voltage source converter, a first end of the third voltage source converter, and a first end of the DC transformer, respectively; the second end of the second voltage source converter is connected to the second AC power source; the second end of the third voltage source converter is connected to the third AC power source; and the second end of the DC transformer is connected to the target load;

[0007] The first AC power source, the second AC power source, and the third AC power source are used to provide AC power to the system; the first voltage source converter, the second voltage source converter, and the third voltage source converter are used to convert the AC power in the system into DC power to obtain target DC power; the DC transformer is used to perform voltage conversion on the target DC power to provide a suitable DC voltage for the target load;

[0008] The target controller is used to monitor the working state of the system and regulate and control the system based on the working state to achieve a flexible connection between the AC power supply in the system and the target load.

[0009] In a second aspect, an embodiment of the present application provides a method for starting an AC / DC multi-port flexible interconnection system, which is applied to the AC / DC multi-port flexible interconnection system as described in the first aspect, and the method includes:

[0010] Obtaining the number of target ports in the system;

[0011] Determining the operating modes supported by the system according to the number of target ports to obtain multiple operating modes;

[0012] Obtaining target usage requirements of a target object; the target object is a user of the system;

[0013] Selecting a target operating mode corresponding to the target usage requirement from the multiple operating modes; the target operating mode includes one of the following: a single-terminal operating mode, a dual-terminal operating mode, a three-terminal operating mode, and a four-terminal operating mode;

[0014] The system is started according to the target operation mode, so that the system supplies power to the target load.

[0015] In a third aspect, the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program for electronic data exchange, wherein the computer program enables a computer to execute some or all of the steps described in the second aspect of the present application.

[0016] The implementation of this application has the following beneficial effects:

[0017] It can be seen that the startup method of the AC / DC multi-port flexible interconnection system described in the present application is applied to the AC / DC multi-port flexible interconnection system, including: obtaining the target port number in the system; determining the operating mode supported by the system based on the target port number to obtain multiple operating modes; obtaining the target usage requirements of the target object; the target object is the user of the system; selecting the target operating mode corresponding to the target usage requirements from multiple operating modes; starting the system according to the target operating mode so that the system can power the load. By understanding the user needs to select the target operating mode, it is possible to avoid starting an operating mode that is not suitable for the user needs, thereby reducing potential startup risks and further achieving safe startup of the AC / DC multi-port flexible interconnection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the background technology, the drawings required for use in the embodiments of the present application or the background technology will be described below.

[0019] Figure 1 This is a structural diagram of an AC / DC multi-port flexible interconnection system provided in an embodiment of the present application;

[0020] Figure 2 This is a flow chart of a method for starting an AC / DC multi-port flexible interconnection system provided in an embodiment of the present application;

[0021] Figure 3 This is a block diagram of the functional units of a starting device for an AC / DC multi-port flexible interconnection system provided in an embodiment of the present application;

[0022] Figure 4 This is a structural diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] The terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish between different objects, not to describe a particular order. Furthermore, the terms "including," "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0025] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] The electronic device mentioned in the embodiments of the present application may include an AC / DC multi-port flexible interconnection system.

[0027] The following is an explanation of some professional terms involved in this application:

[0028] A flexible interconnection system (FIS) is an advanced power transmission and distribution architecture designed to enable flexible and efficient connections between different power sources and loads. FIS typically features multiple ports that can connect different types of power sources (e.g., AC, DC, and renewable energy generation equipment) and loads (e.g., industrial and residential power equipment, and electric vehicle charging stations). These ports can be AC, DC, or a combination of AC and DC, and are connected via advanced power electronics.

[0029] A voltage source converter (VSC) is a power conversion device based on fully controlled power electronic devices (e.g., insulated gate bipolar transistors). It converts input AC power to DC power, or vice versa, by controlling the high-frequency switching of these power electronic devices, enabling bidirectional flow and flexible control of electrical energy.

[0030] A direct current transformer (DCT) is a DC voltage conversion device based on power electronics technology. It converts input DC voltage into DC output voltages of varying voltage levels by controlling the high-frequency switching of power electronic components, enabling efficient transmission and distribution of DC power.

[0031] DC bus: In flexible interconnected systems, the DC bus plays a key role in connectivity and energy transmission. Different power sources and loads are connected to the DC bus through power electronic converters (e.g., VSCs, DCTs), enabling energy sharing and interaction. The DC bus offers low losses, high reliability, and flexible control, improving system efficiency and stability.

[0032] Uncontrolled charging: refers to a relatively simple and basic charging method. Specifically, during the charging process, no complex control circuits or control strategies are used to precisely control parameters such as charging current and voltage. Instead, the power supply is directly connected to the charged device, and the power supply provides power to the charged device with its own output characteristics.

[0033] See also Figure 1 , Figure 1 : This is a structural diagram of an AC / DC multi-port flexible interconnection system provided in an embodiment of the present application; the AC / DC multi-port flexible interconnection system (hereinafter referred to as the system) may include: a target controller, a first AC power source AC1, a second AC power source AC2, a third AC power source AC3, a first voltage source converter VSC1, a second voltage source converter VSC2, a third voltage source converter VSC3, a DC transformer DCT, and a target load Load, wherein:

[0034] The first AC power source AC1 is connected to a first end of the first voltage source converter VSC1, and the second end of the first voltage source converter VSC1 is respectively connected to a first end of the second voltage source converter VSC2, a first end of the third voltage source converter VSC3, and a first end of the DC transformer DCT; the second end of the second voltage source converter VSC2 is connected to the second AC power source AC2; the second end of the third voltage source converter VSC3 is connected to the third AC power source AC3; and the second end of the DC transformer DCT is connected to a target load Load;

[0035] In a specific embodiment, the target load Load includes at least one of the following: a DC load, a DC power supply, etc., which are not limited here; for example, Figure 1 As shown, the target load Load may include equipment such as photovoltaic power generation equipment and charging piles. Among them, the photovoltaic power generation equipment has both power consumption and power generation functions, so the photovoltaic power generation equipment is both a DC power source and a DC load. The charging pile only has the power consumption function, so the charging station is only a DC load. Of course, the target load Load may also include other power-consuming equipment, which is not limited here.

[0036] It should be explained that a DC power supply refers to a device or system that can provide DC power; a DC load refers to a device or system that consumes DC power. During operation, the DC load obtains electrical energy from the DC power supply and converts it into other forms of energy; the second end of the first AC power supply AC1, the second end of the second AC power supply AC2, and the second end of the third AC power supply AC3 can all be grounded.

[0037] The first AC power source AC1, the second AC power source AC2, and the third AC power source AC3 are used to provide AC power to the system; the first voltage source converter VSC1, the second voltage source converter VSC2, and the third voltage source converter VSC3 are used to convert the AC power in the system into DC power to obtain the target DC power; the DC transformer DCT is used to convert the voltage of the target DC power to provide a suitable DC voltage for the target load Load;

[0038] The target controller is used to monitor the working status of the system and adjust and control the system based on the working status to achieve a flexible connection between the AC power supply in the system and the target load Load.

[0039] In the embodiment of the present application, the target controller may include at least one of the following: a programmable logic controller, a microprocessor, an industrial control computer, etc., which is not limited here.

[0040] In a specific embodiment, the target controller is connected to the system for communication. Figure 1Not drawn in the figure; the target controller can collect key parameter data in real time through various sensors installed in the system. For example, a voltage or current sensor or a power sensor can be set at the output position of the AC power supply. The voltage sensor monitors the output voltage of the AC power supply, the current sensor monitors the current in the line, and the power sensor monitors the active power and reactive power of the system. Based on the collected data, the target controller analyzes the working status of the system. For example, by comparing the difference between the actual voltage and the rated voltage, it determines whether the system voltage is stable and predicts possible faults. If the system working status is found to be abnormal, for example, the voltage fluctuation is too large, the target controller can maintain the voltage stability in the system by adjusting the output voltage of the VSC device or DCT device.

[0041] Optionally, the first voltage source converter VSC1, the second voltage source converter VSC2, the third voltage source converter VSC3, and the DC transformer DCT are all connected via a DC bus; the DC bus may also be connected to an energy storage device (for example, a capacitor, a battery, etc.); the DC transformer DCT is connected to the target load Load via a low-voltage DC bus; the first voltage source converter VSC1, the second voltage source converter VSC2, and the third voltage source converter VSC3 are used to convert AC power in the system into DC power to obtain target DC power, which may include the following steps:

[0042] The AC power input from the first AC power source AC1 is processed by the first voltage source converter VSC1 to obtain a first DC power; the AC power input from the second AC power source AC2 is processed by the second voltage source converter VSC2 to obtain a second DC power; the AC power input from the third AC power source AC3 is processed by the third voltage source converter VSC3 to obtain a third DC power; since the VSC device is a common device, the principle of converting AC power into DC power through the VSC device will not be repeated here.

[0043] Next, the target superimposed voltages corresponding to the first DC power, the second DC power, and the third DC power can be determined. Specifically, a voltage sensor can be provided on the DC bus. The voltage sensor detects real-time sampling of the DC bus to obtain multiple voltages. The average of these multiple voltages is calculated, which is the target superimposed voltage. Then, the difference voltage between the target superimposed voltage and the preset required voltage can be determined. The specific calculation formula is as follows:

[0044] Target difference voltage = target superposition voltage - preset required voltage;

[0045] According to the above formula, the target differential voltage can be obtained; then, the target electric energy corresponding to the target differential voltage can be determined. Specifically, a mapping relationship between a preset differential voltage and electric energy can be pre-stored, and the target electric energy corresponding to the target differential voltage can be determined based on the mapping relationship; finally, the target electric energy of the first DC power, the second DC power, and the third DC power can be transmitted to the energy storage device through the DC bus. Specifically, a preset start signal can be sent to the energy storage device through the target controller to start the energy storage device to receive the electric energy on the DC bus until the electric energy received by the energy storage device is equal to the target electric energy, and then the energy storage device is turned off, so that the voltage of the DC bus is maintained near the preset required voltage to obtain the target DC power.

[0046] It should be explained that the preset demand voltage can be preset or defaulted in advance, and it refers to a desired DC bus voltage set according to user or load requirements; the target electric energy refers to the specific electric energy value that needs to be extracted from the first DC power, the second DC power, and the third DC power or injected into the energy storage device in order to maintain the voltage of the DC bus near the preset demand voltage, and its unit can be watt-hour (Wh) or kilowatt-hour (kWh).

[0047] See also Figure 2 , Figure 2 This is a flow chart of a method for starting an AC / DC multi-port flexible interconnection system provided in an embodiment of the present application; applied to the AC / DC multi-port flexible interconnection system, the method includes:

[0048] S1. Obtain the number of target ports in the system.

[0049] In the embodiments of the present application, ports refer to different types of electrical connection points in the system, through which connection and energy interaction between various power supplies, loads, and energy storage devices can be achieved.

[0050] In a specific embodiment, the circuit structure data of the system may be obtained, and the number of electrical connection points in the system, that is, the number of target ports, may be determined based on the circuit structure data. For example, Figure 1 The AC / DC multi-port flexible interconnection system shown includes four electrical connection points and 4 ports, that is, the number of target ports is four, namely the first voltage source converter, the second voltage source converter, the third voltage source converter, and the DC transformer.

[0051] S2. Determine the operating modes supported by the system according to the number of target ports to obtain multiple operating modes.

[0052] In an embodiment of the present application, after obtaining the target number of ports, the ports in the system can be classified to clarify the functions and characteristics of different types of ports. For example, the ports can be divided into AC input ports, AC output ports, DC input ports, DC output ports, energy storage ports, etc. Then, different combinations of the ports with the target number of ports are analyzed to determine possible operating modes and obtain multiple operating modes. For example, assuming that the system has only one port, then the system can only support single-ended operation mode. For another example, assuming that the system has three ports, then the system can support single-ended operation mode, dual-ended operation mode, and three-terminal operation mode.

[0053] S3. Obtain target usage requirements of a target object; the target object is a user of the system.

[0054] In the embodiment of the present application, the target usage requirement may include at least one of the following: voltage requirement, power requirement, power quality requirement, etc., which are not limited here.

[0055] In a specific embodiment, an electricity demand questionnaire can be designed for the target object. The content of the questionnaire may include the type of electrical equipment, electricity power demand, electricity consumption time distribution, requirements for power quality, whether there are special electricity demand, etc. Through the questionnaire survey, a large amount of basic usage demand information of the target object can be collected, thereby obtaining the target usage demand. Alternatively, the historical electricity consumption data of the target object can be obtained, and the historical electricity consumption data can be analyzed to obtain the target usage demand.

[0056] S4. Select a target operating mode corresponding to the target usage requirement from the multiple operating modes; the target operating mode includes one of the following: a single-terminal operating mode, a dual-terminal operating mode, a three-terminal operating mode, and a four-terminal operating mode.

[0057] In an embodiment of the present application, the required number of ports for the target object can be determined based on the target usage requirements, and then the target operating mode can be determined based on the required number of ports. For example, a mapping relationship between a preset number of ports and an operating mode can be pre-stored, and the target operating mode corresponding to the required number of ports can be determined based on the mapping relationship.

[0058] S5. Start the system according to the target operation mode, so that the system supplies power to the target load.

[0059] Optionally, step S5, starting the system according to the target operation mode, may include the following steps:

[0060] A1. Select ports from the system according to the target usage requirements to obtain m ports, where m is a positive integer less than or equal to the target number of ports; each port includes one of the following: the first voltage source converter, the second voltage source converter, the third voltage source converter, or the DC transformer;

[0061] A2. Obtain a control method corresponding to each of the m ports to obtain m control methods;

[0062] A3. Determine a first startup timing according to the m control methods;

[0063] A4. Control the m ports in sequence according to the first startup sequence to operate using corresponding control methods among the m control methods to start the system.

[0064] In the embodiment of the present application, the control method may include at least one of the following: a constant voltage control method, a constant current control method, a constant reactive power control method, a constant low-voltage side voltage control method, etc., which are not limited here.

[0065] In a specific embodiment, the port type required by the target object can be determined based on the target usage requirements to obtain at least one port type. Then, ports can be selected from the system based on the at least one port type to obtain m ports. For example, if the target usage requirement is to power a data center, and the data center requires high-quality DC power, then the port type required by the target object can be a DC input port. By selecting ports with the port type of a DC input port from the system, m ports can be obtained.

[0066] Next, the control method corresponding to each of the m ports can be obtained to obtain m control methods; then, the first startup timing can be determined according to the m control methods; finally, the m ports can be controlled in sequence according to the first startup timing, and the corresponding ports can be controlled with a control method among the m control methods, thereby starting the system.

[0067] In this way, by selecting ports and corresponding control methods based on target usage requirements, it is possible to ensure that the system configuration is highly consistent with actual needs. Different target usage scenarios have different requirements for power supply type, load characteristics, power quality, etc. In this way, appropriate ports and control methods can be selected in a targeted manner, so that the system can better adapt to various complex and diverse application scenarios and improve the versatility and compatibility of the system.

[0068] Optionally, step A2, obtaining the control method corresponding to each of the m ports to obtain m control methods, may include the following steps:

[0069] B1. Obtain a target device type of a first port; the first port is any port among the m ports;

[0070] B2. Determine a control method set corresponding to the first port according to the target device type;

[0071] B3. Determine a first functional requirement of the system for the first port;

[0072] B4. Selecting a control method corresponding to the first port from the control method set according to the first functional requirement.

[0073] In an embodiment of the present application, a target device type of the first port may be first obtained. Specifically, a system design document may be obtained, and port information of the first port may be queried from the design document to obtain the target device type. Next, a control method set corresponding to the first port may be determined based on the target device type. Specifically, a mapping relationship between preset device types and control method sets may be pre-stored. A target control method set corresponding to the target device type may be determined based on the mapping relationship. The target control method set is the control method set corresponding to the first port. Next, a first functional requirement of the system for the first port may be determined. Specifically, a position of the first port in the system and a relationship between the first port and other ports and devices may be obtained. The first functional requirement may be determined based on the position and relationship. For example, assuming that one side of the first port is connected to a DC power supply and the other side is connected to a data center, and the data center requires stable DC power, then the first functional requirement of the first port is to provide stable DC power to the data center. Finally, a control method corresponding to the first port may be selected from the control method set based on the first functional requirement. For example, assuming that the first functional requirement is to provide a stable voltage, a constant voltage control method may be selected from the control method set as the control method corresponding to the first port. Alternatively, a system staff may assign a suitable control method to the first port.

[0074] In this way, by obtaining the target device type of the first port, determining the corresponding control method set, clarifying the system's functional requirements for the port, and selecting the appropriate control method, the control accuracy can be improved, the stability and reliability of the system can be enhanced, and the adaptability and flexibility of the system can be improved. At the same time, it facilitates the management and maintenance of the system, and provides strong guarantees for the efficient and safe operation of the AC / DC multi-port flexible interconnection system.

[0075] Optionally, step A3, determining the first startup sequence according to the m control methods, may include the following steps:

[0076] C1. Determine the port priority corresponding to each of the m ports to obtain m port priorities;

[0077] C2. Determine a reference startup sequence according to the m port priorities; the greater the port priority, the earlier the startup sequence;

[0078] C3. Determine the control characteristics corresponding to each of the m control methods to obtain m control characteristics;

[0079] C4. Determine the dependency relationships between the m control methods based on the m control characteristics to obtain n dependency relationships, where n is a natural number;

[0080] C5. Adjust the reference startup timing according to the n dependencies to obtain the first startup timing.

[0081] In the embodiment of the present application, the control characteristics may include at least one of the following: constant voltage, constant current, constant power, etc., which are not limited here.

[0082] In a specific embodiment, the port priority corresponding to each of the m ports can be determined first to obtain m port priorities. Specifically, the ports can be divided into different priorities based on the importance of the load or equipment connected to each of the m ports, thereby obtaining m port priorities. For example, for a system that supplies power to industrial production and office areas, the power supply port connected to large-scale production equipment can be classified as high priority, while the port connected to office computers and lighting equipment can be classified as low priority. Then, a reference startup sequence can be determined based on the m port priorities. The greater the port priority, the earlier the startup sequence.

[0083] Furthermore, the control characteristics corresponding to each of the m control methods can be determined to obtain m control characteristics. For example, a mapping relationship between a preset control method and electric energy can be pre-stored, and the m control characteristics corresponding to the m control methods can be determined based on the mapping relationship. Then, the dependency relationship between the m control methods can be determined based on the m control characteristics to obtain n dependency relationships. Starting from the first control method among the m control methods, it can be analyzed in turn whether there is a dependency relationship between it and the other control methods. The basis for judgment is whether the control characteristics or normal operation of a control method directly depends on the result or condition produced by another control method. For example, assuming that in the system, the control characteristic of the reactive and active control method is that the power remains unchanged, it is necessary to use the voltage and current of each port to determine whether the control characteristics of the reactive and active control method are directly dependent on the result or condition produced by another control method. Power calculation and distribution are performed based on the flow value, that is, the constant reactive power control method depends on the constant voltage (constant voltage control method) and / or constant current (constant current control method); finally, the reference startup timing can be adjusted according to n dependencies to obtain a first startup timing. Specifically, the dependent control method can be placed before the control method that depends on it to ensure that the dependent control method is started before the control method that depends on it to obtain the first startup timing. For example, assuming that the reference startup timing is control method A→control method B→control method C, but control method C depends on control method B, so control method B needs to be started first before control method C can be used, then the first startup timing after adjustment is control method A→control method C→control method B.

[0084] By determining the port priority of each port, the importance of each port in the system can be clearly identified. This helps to prioritize the needs of high-priority ports and achieve reasonable resource allocation when resources are limited.

[0085] Optionally, in step S5, when the target operation mode includes the four-terminal operation mode, starting the system according to the target operation mode may include the following steps:

[0086] D1. Determine four ports in the system; the four ports include: the first voltage source converter, the second voltage source converter, the third voltage source converter, and the DC transformer;

[0087] D2. Determine that the control method of the first voltage source converter is a constant voltage control method, the control methods of the second voltage source converter and the third voltage source converter are both constant active and reactive power control methods, and the control method of the DC transformer is a constant low-side voltage control method;

[0088] D3. Obtain a second startup sequence corresponding to the four ports; the second startup sequence is: first start the first voltage source converter, then start the second voltage source converter and the third voltage source converter, and finally start the DC transformer;

[0089] D4. Control the four ports in sequence to operate using corresponding control methods according to the second startup sequence to start the system.

[0090] In an embodiment of the present application, all ports included in the system can be determined to obtain four ports, which include: a first voltage source converter, a second voltage source converter, a third voltage source converter, and a DC transformer; then, a second startup timing corresponding to the four ports can be obtained; according to the second startup timing, the four ports are controlled in sequence to operate with a corresponding control method to start the system.

[0091] Optionally, in some embodiments, when the system operates in a single-ended operation mode, the system startup process may be as follows: a certain port may be directly selected from the system, and the port may be controlled to perform uncontrolled charging until the uncontrolled charging is completed, that is, the system startup is completed. For example, VSC1 may be selected as the port, and uncontrolled charging may be performed on VSC1 through the first AC power supply. After the uncontrolled charging is completed, VSC1 may be unlocked and constant DC voltage control may be performed. At this time, the system only relies on VSC1 to operate, and its output stable DC voltage can be used as an independent DC power supply to power the load in the system, or as a DC voltage reference when subsequently connected to other devices, providing a basis for system expansion and interconnection.

[0092] Optionally, in some embodiments, when the system operates in a dual-end operation mode, the system startup process may be:

[0093] Assume that the double-ended operation mode is that VSC1 and VSC2 are put into operation;

[0094] Control mode: VSC1 is constant voltage control, VSC2 is constant active and reactive power control;

[0095] Startup sequence: VSC1→VSC2;

[0096] Startup process: VSC1 is charged uncontrolled through the first AC power source. After completion, VSC1 is unlocked for constant DC voltage control, and then VSC2 is unlocked to interconnect the AC power sources at both ends.

[0097] Assume that the dual-end operation mode is that VSC1 and DCT are put into operation;

[0098] Control mode: VSC1 is constant voltage control, DCT is constant low-side voltage control;

[0099] Startup sequence: VSC1→DCT;

[0100] Startup process: First, VSC1 is charged uncontrolled through the first AC power supply. After completion, VSC1 is unlocked to perform constant DC voltage control, and then DCT is unlocked to establish the low-voltage side bus voltage.

[0101] Optionally, in some embodiments, when the system operates in a three-terminal mode, the system startup process is as follows:

[0102] Assume that the three-terminal operation mode is that VSC1, VSC2 and DCT are put into operation;

[0103] Control mode: VSC1 is constant voltage control, VSC2 is constant active and reactive power control, and DCT is constant low-voltage side voltage control;

[0104] Startup sequence: VSC1→VSC2→DCT;

[0105] Startup process: First, VSC1 is charged uncontrolled through the first AC power supply. After the uncontrolled charging is completed, VSC1 is unlocked and constant DC voltage control is performed. Then, VSC2 is unlocked to achieve AC power supply interconnection. Finally, DCT is unlocked to establish the low-voltage side DC bus voltage to complete the startup.

[0106] Assume that the three-terminal operation mode is that VSC1, VSC2 and VSC3 are put into operation;

[0107] Control mode: VSC1 is constant voltage control, VSC2 is constant active and reactive power control, and VSC3 is constant low-voltage side voltage control;

[0108] Startup sequence: VSC1→VSC2+VSC3;

[0109] Startup process: First, VSC1 is charged uncontrolled through the first AC power supply. After completion, VSC1 is unlocked to perform constant DC voltage control, and then VSC2 and VSC3 are unlocked to achieve AC power interconnection and complete startup.

[0110] Optionally, step D4, sequentially controlling the four ports to operate in a corresponding control method according to the second startup sequence to start the system, may include the following steps:

[0111] E1. Perform uncontrolled charging on the first voltage source converter using the first AC power supply until uncontrolled charging is completed, unlock the first voltage source converter, and perform the constant voltage control method.

[0112] E2. Unlocking the second voltage source converter and the third voltage source converter, and performing the fixed active and reactive power control method;

[0113] E3, unlocking the DC transformer and performing the low-voltage-side voltage control method to generate a low-voltage-side DC bus voltage at the low-voltage side of the DC transformer, and the system is started up.

[0114] In the embodiments of the present application, the first voltage source converter can be uncontrolled charged by the first AC power supply until the uncontrolled charging is completed, and the current conversion function (for example, AC to DC or DC to AC) of the first voltage source converter is unlocked. Specifically, the unlocking is performed by the target controller issuing a first preset pulse signal to the first voltage source converter to control the switching device in the first voltage source converter to be turned on. After the unlocking, the first voltage source converter can be controlled by using the constant voltage control method.

[0115] Then, the second voltage source converter and the third voltage source converter can be unlocked. Similarly, the target controller can issue a second preset pulse signal to the second voltage source converter and a third preset pulse signal to the third voltage source converter to unlock the current conversion function of the second voltage source converter and the third voltage source converter. After the unlocking, the second voltage source converter and the third voltage source converter can be controlled by using the constant active and reactive power control method. Finally, the target controller can issue a fourth preset pulse signal to the DC transformer to unlock the voltage conversion function of the DC transformer, and the DC transformer can be controlled by using the low-voltage-side voltage control method. Thus, a low-voltage-side DC bus voltage is generated at the low-voltage side (the side connected to the target load) of the DC transformer, and the system is started up.

[0116] In this way, the first voltage source converter is uncontrolled charged by the first AC power supply. This method does not require a complex control circuit and an accurate charging control strategy, and the charging process is relatively simple and direct. The first voltage source converter can be quickly charged to the working state, and the starting speed of the system is accelerated.

[0117] Optionally, step E1, the uncontrolled charging of the first voltage source converter by the first AC power supply until the uncontrolled charging is completed, can include the following steps:

[0118] F1, obtaining a first converter model corresponding to the first voltage source converter;

[0119] F2, determining a first unlocking voltage and a first voltage threshold corresponding to the first converter model;

[0120] F3, determining a difference between the first unlocking voltage and the first voltage threshold to obtain a first voltage difference;

[0121] F4, determining a first ratio according to the first voltage difference and the first voltage threshold;

[0122] F5, obtaining a target usage duration of the first voltage source converter;

[0123] F6, determining a target attenuation factor corresponding to the target usage duration;

[0124] F7, adjusting the first voltage threshold according to the target attenuation factor to obtain a second voltage threshold;

[0125] F8, determining a difference between the first unlocking voltage and the second power threshold to obtain a second voltage difference;

[0126] F9, determining a second ratio according to the second voltage difference and the second voltage threshold;

[0127] F10, determining a difference between the first ratio and the second ratio to obtain a target difference;

[0128] F11, determining a target adjustment coefficient corresponding to the target difference;

[0129] F12, adjusting the first unlocking voltage according to the target adjustment coefficient to obtain a second unlocking voltage;

[0130] F13, uncontrolled charging the first voltage source converter by the first alternating current power supply so that the voltage of the first voltage source converter reaches the second unlocking voltage, and the uncontrolled charging is completed.

[0131] In the embodiments of the application, the first voltage threshold represents the upper limit of the voltage of the first voltage source converter when the first voltage source converter is normally working.

[0132] In specific embodiments, the first converter model corresponding to the first voltage source converter can be obtained first, specifically, the target controller can query the device information of the first voltage source converter from the design document of the system, so as to obtain the first converter model; then, the first unlocking voltage and the first voltage threshold corresponding to the first converter model can be determined, for example, a preset mapping relationship between the converter model and the unlocking voltage and the voltage threshold can be stored in advance, and the first unlocking voltage and the first voltage threshold corresponding to the first converter model are determined based on the mapping relationship; then, the difference between the first unlocking voltage and the first voltage threshold can be calculated, and the specific calculation formula is as follows:

[0133] First voltage difference = first unlocking voltage - first voltage threshold;

[0134] According to the above formula, the first voltage difference can be obtained; further, the first ratio can be determined according to the first voltage difference and the first voltage threshold, and the specific calculation formula is as follows:

[0135] First ratio=first voltage difference / first voltage threshold;

[0136] According to the above formula, the first ratio can be obtained; then, the target usage time of the first voltage source converter can be obtained. Specifically, the factory time of the first voltage source converter and the current time can be obtained, and the target usage time can be obtained by subtracting the factory time from the current time; then, the target attenuation factor corresponding to the target usage time can be determined. Specifically, a mapping relationship between preset usage time and attenuation factor can be pre-stored, and the target attenuation factor corresponding to the target usage time can be determined based on the mapping relationship, wherein the value range of the target attenuation factor can be -0.3 to 0; then, the first voltage threshold can be adjusted according to the target attenuation factor. The specific calculation formula is as follows:

[0137] Second voltage threshold = first voltage threshold * (1 + target attenuation factor);

[0138] The second voltage threshold can be obtained according to the above formula. Then, the second power threshold can be subtracted from the first unlock voltage to obtain the second voltage difference. Then, the second voltage difference and the second voltage threshold can be used for calculation. The specific calculation formula is as follows:

[0139] Second ratio=second voltage difference / second voltage threshold;

[0140] The second ratio can be obtained according to the above formula; then, the target difference can be obtained by subtracting the second ratio from the first ratio; then, the target adjustment coefficient corresponding to the target difference can be determined. For example, a mapping relationship between a preset difference and an adjustment coefficient can be pre-stored, and the target adjustment coefficient corresponding to the target difference can be determined based on the mapping relationship, wherein the target adjustment coefficient can range from -0.2 to 0.2; further, the first unlocking voltage can be adjusted according to the target adjustment coefficient. The specific calculation formula is as follows:

[0141] Second unlocking voltage = first unlocking voltage * (1 + target adjustment coefficient);

[0142] The second unlocking voltage can be obtained according to the above formula; finally, the first voltage source converter can be charged uncontrolled by the first AC power supply, and when the voltage of the first voltage source converter reaches the second unlocking voltage, it is determined that the uncontrolled charging is completed.

[0143] The implementation of this application has the following beneficial effects:

[0144] It can be seen that the startup method of the AC / DC multi-port flexible interconnection system described in the present application is applied to the AC / DC multi-port flexible interconnection system, including: obtaining the target port number in the system; determining the operating mode supported by the system based on the target port number to obtain multiple operating modes; obtaining the target usage requirements of the target object; the target object is the user of the system; selecting the target operating mode corresponding to the target usage requirements from multiple operating modes; starting the system according to the target operating mode so that the system can power the load. By understanding the user needs to select the target operating mode, it is possible to avoid starting an operating mode that is not suitable for the user needs, thereby reducing potential startup risks and further achieving safe startup of the AC / DC multi-port flexible interconnection system.

[0145] See also Figure 3 , Figure 3 This is a block diagram of the functional units of a starting device 300 for an AC / DC multi-port flexible interconnection system provided in an embodiment of the present application; the starting device 300 for an AC / DC multi-port flexible interconnection system is applied to the AC / DC multi-port flexible interconnection system described in any of the above embodiments. The starting device 300 for an AC / DC multi-port flexible interconnection system includes: an acquisition unit 301, a control unit 302, and a starting unit 303, wherein:

[0146] The acquiring unit 301 is configured to acquire the number of target ports in the system;

[0147] The control unit 302 is configured to determine the operating modes supported by the system according to the number of target ports, and obtain multiple operating modes;

[0148] The acquisition unit 301 is further configured to acquire target usage requirements of a target object; the target object is a user of the system;

[0149] The control unit 302 further selects a target operating mode corresponding to the target usage requirement from the multiple operating modes; the target operating mode includes one of the following: a single-terminal operating mode, a dual-terminal operating mode, a three-terminal operating mode, and a four-terminal operating mode;

[0150] The starting unit 303 is configured to start the system according to the target operation mode, so that the system supplies power to the target load.

[0151] Optionally, in starting the system according to the target operation mode, the starting unit 303 is specifically configured to:

[0152] Selecting ports from the system according to the target usage requirements to obtain m ports; m is a positive integer less than or equal to the target number of ports; each port includes one of the following: the first voltage source converter, the second voltage source converter, the third voltage source converter, and the DC transformer;

[0153] Obtaining a control method corresponding to each of the m ports to obtain m control methods;

[0154] Determining a first startup timing according to the m control methods;

[0155] The m ports are controlled in sequence according to the first startup sequence to operate using corresponding control methods among the m control methods, so as to start the system.

[0156] Optionally, in acquiring the control method corresponding to each of the m ports to obtain the m control methods, the acquiring unit 301 is specifically configured to:

[0157] Obtaining a target device type of a first port; the first port is any port among the m ports;

[0158] Determining a control method set corresponding to the first port according to the target device type;

[0159] determining a first functional requirement of the system for the first port;

[0160] A control method corresponding to the first port is selected from the control method set according to the first functional requirement.

[0161] Optionally, in determining the first startup sequence according to the m control methods, the startup unit 303 is specifically configured to:

[0162] Determine the port priority corresponding to each port in the m ports to obtain m port priorities;

[0163] Determine a reference startup sequence according to the m port priorities; the greater the port priority, the earlier the startup sequence;

[0164] Determining a control characteristic corresponding to each of the m control methods to obtain m control characteristics;

[0165] Determine the dependency relationships between the m control methods according to the m control characteristics to obtain n dependency relationships, where n is a natural number;

[0166] The reference startup timing is adjusted according to the n dependencies to obtain the first startup timing.

[0167] Optionally, when the target operation mode includes the four-terminal operation mode, the system is started according to the target operation mode, and the starting unit 303 is specifically configured to:

[0168] Determine four ports in the system; the four ports include: the first voltage source converter, the second voltage source converter, the third voltage source converter, and the DC transformer;

[0169] Determining that the control method of the first voltage source converter is a constant voltage control method, the control methods of the second voltage source converter and the third voltage source converter are both constant active and reactive power control methods, and the control method of the DC transformer is a constant low-side voltage control method;

[0170] Obtaining a second startup sequence corresponding to the four ports; the second startup sequence is: first starting the first voltage source converter, then starting the second voltage source converter and the third voltage source converter, and finally starting the DC transformer;

[0171] The four ports are controlled in sequence to operate in a corresponding control method according to the second startup sequence to start the system.

[0172] Optionally, in the aspect of sequentially controlling the four ports to operate in a corresponding control method according to the second startup timing to start the system, the startup unit 303 is specifically configured to:

[0173] performing uncontrolled charging on the first voltage source converter by using the first AC power supply until the uncontrolled charging is completed, unlocking the first voltage source converter, and performing the constant voltage control method;

[0174] Unlocking the second voltage source converter and the third voltage source converter, and performing the fixed active and reactive power control method;

[0175] The DC transformer is unlocked, and the fixed low-voltage side voltage control method is performed to generate a low-voltage side DC bus voltage on the low-voltage side of the DC transformer, and the system startup is completed.

[0176] Optionally, in the aspect of performing uncontrolled charging on the first voltage source converter by using the first AC power supply until the uncontrolled charging is completed, the starting unit 303 is specifically configured to:

[0177] Obtaining a first converter model corresponding to the first voltage source converter;

[0178] Determining a first unlocking voltage and a first voltage threshold corresponding to the first converter model;

[0179] determining a difference between the first unlocking voltage and the first voltage threshold to obtain a first voltage difference;

[0180] determining a first ratio according to the first voltage difference and the first voltage threshold;

[0181] Obtaining a target usage time of the first voltage source converter;

[0182] Determining a target attenuation factor corresponding to the target usage duration;

[0183] Adjusting the first voltage threshold according to the target attenuation factor to obtain a second voltage threshold;

[0184] determining a difference between the first unlocking voltage and the second power threshold to obtain a second voltage difference;

[0185] determining a second ratio according to the second voltage difference and the second voltage threshold;

[0186] determining a difference between the first ratio and the second ratio to obtain a target difference;

[0187] Determining a target adjustment coefficient corresponding to the target difference;

[0188] adjusting the first unlocking voltage according to the target adjustment coefficient to obtain a second unlocking voltage;

[0189] The first voltage source converter is uncontrolled charged by the first AC power supply so that the voltage of the first voltage source converter reaches the second unlocking voltage, and the uncontrolled charging is completed.

[0190] In a specific implementation, the starting device 300 of the AC / DC multi-port flexible interconnection system described in the embodiment of the present invention can also execute other implementations described in the starting method of the AC / DC multi-port flexible interconnection system provided by the above embodiment of the present invention, which will not be repeated here.

[0191] See also Figure 4 , Figure 4 This is a structural diagram of an electronic device provided in an embodiment of the present application, which includes a processor, a memory, a communication interface, and one or more programs. The processor, memory, and communication interface are interconnected via a bus. The one or more programs are stored in the memory and are configured to be executed by the processor. The one or more programs include instructions for executing other implementations described in the startup method of the AC / DC multi-port flexible interconnection system provided in the above embodiment of the present invention, which will not be repeated here.

[0192] An embodiment of the present application also provides a computer storage medium, wherein the computer storage medium stores a computer program for electronic data exchange, and the computer program enables a computer to execute part or all of the steps of any method described in the above method embodiments, and the above computer includes an electronic device.

[0193] The present application also provides a computer program product comprising a non-transitory computer-readable storage medium storing a computer program, wherein the computer program is operable to cause a computer to execute some or all of the steps of any of the methods described in the above method embodiments. The computer program product may be a software installation package, and the computer may include a charging device.

[0194] It should be noted that for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that this application is not limited by the order of the actions described, because according to this application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by this application.

[0195] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0196] In the several embodiments provided in this application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the above-mentioned units is only a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical or other forms.

[0197] The units described above as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0198] In addition, each of the functional units in the various embodiments of the present application can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0199] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable memory. Based on such understanding, the technical solutions of the present application, essentially or in the part that contributes to the prior art, or all or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a memory and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods according to the various embodiments of the present application. The aforementioned memory includes various media that can store program codes, such as a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, etc.

[0200] The embodiments of the present application are described in detail above, and the specific examples are applied to the principles and implementation modes of the present application. The above description of the embodiments is only used to help understand the method of the present application and its core idea; at the same time, for those skilled in the art, according to the idea of the present application, the specific implementation mode and application range will be changed, and the above description of the embodiments should not be understood as a limitation of the present application.

Claims

1. A method for starting an AC / DC multi-port flexible interconnection system, characterized in that: A flexible interconnection system for AC / DC multi-ports, the system comprising: a target controller, a first AC power source, a second AC power source, a third AC power source, a first voltage source converter, a second voltage source converter, a third voltage source converter, a DC transformer, and a target load, wherein: The first AC power source is connected to a first end of the first voltage source converter, and the second end of the first voltage source converter is connected to a first end of the second voltage source converter, a first end of the third voltage source converter, and a first end of the DC transformer, respectively; the second end of the second voltage source converter is connected to the second AC power source; the second end of the third voltage source converter is connected to the third AC power source; and the second end of the DC transformer is connected to the target load; The first AC power source, the second AC power source, and the third AC power source are used to provide AC power to the system; the first voltage source converter, the second voltage source converter, and the third voltage source converter are used to convert the AC power in the system into DC power to obtain target DC power; the DC transformer is used to perform voltage conversion on the target DC power to provide a suitable DC voltage for the target load; The target controller is used to monitor the working state of the system and adjust and control the system based on the working state to achieve a flexible connection between the AC power supply in the system and the target load; The method comprises: Obtaining the number of target ports in the system; Determining the operating modes supported by the system according to the number of target ports to obtain multiple operating modes; Obtaining target usage requirements of a target object; the target object is a user of the system; Selecting a target operating mode corresponding to the target usage requirement from the multiple operating modes; the target operating mode includes one of the following: a single-terminal operating mode, a dual-terminal operating mode, a three-terminal operating mode, and a four-terminal operating mode; Starting the system according to the target operating mode so that the system supplies power to the target load; Wherein, starting the system according to the target operation mode includes: Selecting ports from the system according to the target usage requirements to obtain m ports; m is a positive integer less than or equal to the target number of ports; each port includes one of the following: the first voltage source converter, the second voltage source converter, the third voltage source converter, and the DC transformer; Obtaining a control method corresponding to each of the m ports to obtain m control methods; Determining a first startup timing according to the m control methods; controlling the m ports in sequence to operate using corresponding control methods among the m control methods according to the first startup sequence, so as to start the system; The step of obtaining the control method corresponding to each of the m ports to obtain the m control methods includes: Obtaining a target device type of a first port; the first port is any port among the m ports; Determining a control method set corresponding to the first port according to the target device type; determining a first functional requirement of the system for the first port; A control method corresponding to the first port is selected from the control method set according to the first functional requirement.

2. The method according to claim 1, wherein The first voltage source converter, the second voltage source converter, the third voltage source converter, and the DC transformer are all connected via a DC bus; the DC bus is also connected to an energy storage device; the DC transformer and the target load are connected via a low-voltage DC bus; the first voltage source converter, the second voltage source converter, and the third voltage source converter are used to convert AC power in the system into DC power to obtain target DC power, including: processing the alternating current inputted from the first alternating current power source by the first voltage source converter to obtain a first direct current; processing the alternating current input from the second alternating current power supply through the second voltage source converter to obtain a second direct current; processing the alternating current inputted from the third alternating current power source by the third voltage source converter to obtain a third direct current; determining target superposition voltages corresponding to the first direct current, the second direct current, and the third direct current; Determining a difference voltage between the target superposition voltage and a preset required voltage to obtain a target difference voltage; Determining a target electric energy corresponding to the target difference voltage; The target electric energy of the first direct current, the second direct current, and the third direct current is transmitted to the energy storage device through the direct current bus to obtain the target direct current.

3. The method according to claim 1, wherein The determining a first startup timing according to the m control methods includes: Determine the port priority corresponding to each port in the m ports to obtain m port priorities; Determine a reference startup sequence according to the m port priorities; the greater the port priority, the earlier the startup sequence; Determining a control characteristic corresponding to each of the m control methods to obtain m control characteristics; Determine the dependency relationships between the m control methods according to the m control characteristics to obtain n dependency relationships, where n is a natural number; The reference startup timing is adjusted according to the n dependencies to obtain the first startup timing.

4. The method according to claim 1 or 3, wherein: When the target operation mode includes the four-terminal operation mode, starting the system according to the target operation mode includes: Determine four ports in the system; the four ports include: the first voltage source converter, the second voltage source converter, the third voltage source converter, and the DC transformer; Determining that the control method of the first voltage source converter is a constant voltage control method, the control methods of the second voltage source converter and the third voltage source converter are both constant active and reactive power control methods, and the control method of the DC transformer is a constant low-side voltage control method; Obtaining a second startup sequence corresponding to the four ports; the second startup sequence is: first starting the first voltage source converter, then starting the second voltage source converter and the third voltage source converter, and finally starting the DC transformer; The four ports are controlled in sequence to operate in a corresponding control method according to the second startup sequence to start the system.

5. The method according to claim 4, wherein The controlling the four ports in sequence to operate in a corresponding control method according to the second startup timing to start the system includes: performing uncontrolled charging on the first voltage source converter by using the first AC power supply until the uncontrolled charging is completed, unlocking the first voltage source converter, and performing the constant voltage control method; Unlocking the second voltage source converter and the third voltage source converter, and performing the fixed active and reactive power control method; The DC transformer is unlocked, and the fixed low-voltage side voltage control method is performed to generate a low-voltage side DC bus voltage on the low-voltage side of the DC transformer, and the system startup is completed.

6. The method according to claim 5, wherein The step of performing uncontrolled charging on the first voltage source converter by using the first AC power supply until the uncontrolled charging is completed includes: Obtaining a first converter model corresponding to the first voltage source converter; Determining a first unlocking voltage and a first voltage threshold corresponding to the first converter model; determining a difference between the first unlocking voltage and the first voltage threshold to obtain a first voltage difference; determining a first ratio according to the first voltage difference and the first voltage threshold; Obtaining a target usage time of the first voltage source converter; Determining a target attenuation factor corresponding to the target usage duration; Adjusting the first voltage threshold according to the target attenuation factor to obtain a second voltage threshold; determining a difference between the first unlocking voltage and the second voltage threshold to obtain a second voltage difference; determining a second ratio according to the second voltage difference and the second voltage threshold; determining a difference between the first ratio and the second ratio to obtain a target difference; Determining a target adjustment coefficient corresponding to the target difference; adjusting the first unlocking voltage according to the target adjustment coefficient to obtain a second unlocking voltage; The first voltage source converter is uncontrolled charged by the first AC power supply so that the voltage of the first voltage source converter reaches the second unlocking voltage, and the uncontrolled charging is completed.

7. A computer-readable storage medium, characterized in that A computer program for electronic data exchange is stored, wherein the computer program enables a computer to execute the method according to any one of claims 1 to 6.

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