A power conversion system

Abstract

The power conversion system comprises at least two power conversion groups, each power conversion group comprising at least two power conversion units connected in parallel on an alternating current side; in each power conversion group, the power conversion units are communicatively connected, one of the power conversion units serving as a master and the others serving as slaves; the master performs logical judgment according to first operation information of the slaves, and issues corresponding first instructions to the slaves; and each power conversion group is communicatively connected through at least one power conversion unit; that is, the power conversion system realizes compatibility of the two communications through the double-layer communication architecture of the group communication and the system communication, and can improve the control coordination between the power conversion units.

Description

Technical Field

[0001] This disclosure relates to the field of power electronics technology, and in particular to a power conversion system. Background Technology

[0002] To meet the ever-increasing power demand and improve system redundancy and reliability, power conversion systems often adopt a modular design concept, which means that multiple power conversion units are connected in parallel or series in a power conversion system, and flexible energy scheduling is achieved through cluster control.

[0003] In this power conversion system, the communication strategy between power conversion units typically adopts a master-slave communication scheme, that is, only one communication master is set up, and the rest of the units are communication slaves. Under this scheme, control information is only exchanged between the communication master and the communication slaves, and the communication slaves cannot directly exchange control information, resulting in poor control coordination between the power conversion units. Summary of the Invention

[0004] In view of the above problems, this disclosure provides a power conversion system to improve the control coordination between power conversion units. The specific solution is as follows:

[0005] This disclosure provides a power conversion system, comprising: at least two power conversion groups, wherein each power conversion group includes: at least two power conversion units connected in parallel on their AC sides; wherein...

[0006] In the power conversion group, each power conversion unit is communicatively connected, wherein one power conversion unit acts as the master unit within the group, and the other power conversion units act as slave units within the group.

[0007] The host in the group is configured to: make logical judgments based on the first operating information of the slave in the group, determine and issue corresponding first instructions to the slave in the group;

[0008] Each power conversion group is connected to the system through at least one of its power conversion units, wherein one power conversion unit acts as the system master and the other power conversion units act as the system slaves.

[0009] In one possible implementation, the host machine within the group is also configured to synchronize control status with the slave machines within the group.

[0010] In one possible implementation, the slave unit within the power conversion group is configured to actively report the first operating information.

[0011] In one possible implementation, the system host is configured to: query the second operating information of each of the system slaves, and, if a preset local control strategy needs to be executed, issue a second instruction to each of the system slaves.

[0012] In one possible implementation, each of the power conversion groups establishes a communication connection through its respective intra-group host.

[0013] In one possible implementation, the intra-group communication between the host and slave devices within the power conversion group, and the system communication between the system host and each of the system slave devices, share a first communication bus.

[0014] In one possible implementation, each of the power conversion units is assigned a corresponding mailbox for implementing the intra-group communication and the system communication.

[0015] In one possible implementation, each of the power conversion units is assigned a corresponding identifier to implement the intra-group communication and the system communication.

[0016] In one possible implementation, the intra-group communication between the host and slave within the power conversion group, and the system communication between the system host and each of the system slaves, are implemented using their respective corresponding communication lines.

[0017] In one possible implementation, the power conversion system further includes: a system controller;

[0018] The system controller and each of the power conversion units are connected via a second communication bus;

[0019] The system controller is configured to: query the third operating information of each of the power conversion units; receive a global scheduling instruction; and generate and issue at least one of a power setting instruction and a start / stop control instruction to each of the power conversion units.

[0020] In one possible implementation, the power conversion unit includes: a DC switch, a power conversion module, an AC filter, and an AC switch;

[0021] The first side of the DC switch is used to connect a DC power supply.

[0022] The second side of the DC switch is connected to the DC side of the power conversion module;

[0023] The AC side of the power conversion module is connected to the first side of the AC switch via the AC filter;

[0024] The second side of the AC switch is connected to the power grid via a grid connection interface.

[0025] In one possible implementation, the power conversion group includes:

[0026] Each of the power conversion units is connected in parallel to the grid interface;

[0027] Alternatively, each of the power conversion units may share the same AC switch and the grid connection interface;

[0028] Alternatively, each of the power conversion units may share the same AC filter, the same AC switch, and the same grid connection interface.

[0029] The power conversion system provided in this disclosure includes at least two power conversion groups, each including at least two power conversion units connected in parallel on the AC side. Within each power conversion group, the power conversion units are communicatively connected, with one power conversion unit acting as the master unit and the other power conversion units acting as slave units. The master unit performs logical judgments based on the first operating information of the slave units, determines and issues corresponding first instructions to the slave units. Furthermore, each power conversion group achieves communication connectivity through at least one of its own power conversion units. That is, this disclosure achieves compatibility between the two communication methods through a two-layer communication architecture of intra-group communication and system communication, thereby improving the control coordination between the power conversion units. Attached Figure Description

[0030] The features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and elements and actual parts are not necessarily drawn to scale.

[0031] Figure 1 A schematic diagram of a power conversion system provided in an embodiment of this disclosure;

[0032] Figure 2 This is a schematic diagram of the first circuit structure of the power conversion group in the power conversion system provided in the embodiments of this disclosure;

[0033] Figure 3 This is a schematic diagram of a second circuit structure of the power conversion group in the power conversion system provided in this embodiment of the disclosure;

[0034] Figure 4 This is a schematic diagram of a third circuit structure of the power conversion group in the power conversion system provided in the embodiments of this disclosure;

[0035] Figure 5 A schematic diagram of a first communication architecture in a power conversion system provided in an embodiment of this disclosure;

[0036] Figure 6A schematic diagram of a second communication architecture in a power conversion system provided in this disclosure embodiment;

[0037] Figure 7 A schematic diagram of a third communication architecture in a power conversion system provided in an embodiment of this disclosure. Detailed Implementation

[0038] The embodiments of this disclosure are described below with reference to the accompanying drawings. The terminology used in the Description of Embodiments section of this disclosure is for illustrative purposes only and is not intended to limit the scope of this disclosure.

[0039] The embodiments of this disclosure are described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure. Those skilled in the art will understand that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of this disclosure are also applicable to similar technical problems.

[0040] The terms “first,” “second,” etc., used in this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the description of embodiments of this disclosure. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of units is not necessarily limited to those units, but may include other units not expressly listed or inherent to those processes, methods, products, or apparatuses.

[0041] This disclosure provides a power conversion system to improve the control coordination between power conversion units. The specific solution is as follows:

[0042] The power conversion system includes at least two power conversion groups 01; such as Figure 1 As shown, the power conversion group 01 includes at least two power conversion units 10 connected in parallel on their AC sides. The specific method by which each power conversion unit 10 achieves parallel AC side connection can be described below. The AC side of each power conversion group 01 can be connected to the power grid through a grid connection point.

[0043] In power conversion group 01, all power conversion units 10 are communicatively connected. One power conversion unit 10 acts as the group's master, while the others act as slaves. Through this communication connection, power conversion group 01 can achieve intra-group communication. The group's master is configured to: perform logical judgment based on the first operating information of the slaves within the group, determine and issue a corresponding first instruction to the slaves. The first operating information may refer to key operating information such as voltage, current, and fault status; the first instruction may refer to a coordinated control instruction obtained after logical judgment of the first operating information, which allows the slaves within the group to directly control the corresponding hardware execution.

[0044] Furthermore, each power conversion group 01 is connected to the system via at least one power conversion unit 10. One power conversion unit 10 acts as the system master, while the others act as system slaves. Through this communication connection, each power conversion group 01 can achieve system communication. The power conversion units used for system communication within each power conversion group 01 are not limited; they can be the master, slave, or both, depending on the specific application environment.

[0045] Figure 2 Taking a power conversion group 01 containing two power conversion units 10 as an example, in each power conversion group 01, one power conversion unit 10 is designated as the group master, and the other power conversion unit 10 is designated as the group slave. While maintaining a single communication master (i.e., the system master mentioned above) throughout the entire system, an intra-group communication layer is introduced, forming a two-layer communication architecture of system communication superimposed on intra-group communication. In the intra-group communication layer, an independent communication channel is established between the two power conversion units 10 within the same power conversion group 01. The group master acts as the master control unit of the group, and the group slave acts as the controlled unit of the group. The intra-group communication layer is responsible for uploading status information and issuing control commands between the group master and the group slave. Specifically, after receiving the first operating information from the slave, the built-in control algorithm performs logical judgments; for example, it determines whether there is uneven output, phase deviation, or potential fault risk between the two power conversion units 10. If adjustment is confirmed, the group master directly generates the corresponding first command and issues it to the group slave, thereby enabling close coordinated control between the two power conversion units 10 within the group.

[0046] The power conversion system provided in this embodiment optimizes system cost and hardware layout by implementing a grouping strategy for the power conversion units 10 within the system. Furthermore, the dual-layer communication architecture, consisting of intra-group communication and system communication, achieves compatibility between the two types of communication, improving control coordination among the power conversion units 10.

[0047] In related technologies, the master-slave communication scheme only sets up one communication master in a multi-machine parallel power conversion system, with the remaining power conversion units acting as communication slaves. Control information is only exchanged between the master and slaves, and the slaves have no mutual control capabilities. This embodiment, however, provides a direct communication channel between the power conversion units 10 within the group through the aforementioned two-layer communication architecture. This allows the master unit to obtain the real-time operating status of the slave units and issue coordinated control commands to them, thereby achieving coordinated control among the power conversion units 10 within the group.

[0048] In practical applications, such as Figure 2 As shown, the power conversion unit 10 in this power conversion system includes: a DC switch 101, a power conversion module 102, an AC filter 103, and an AC switch 104; wherein:

[0049] The first side of the DC switch 101 is used to connect a DC power supply; the DC power supply can refer to one photovoltaic string or at least two photovoltaic strings connected in parallel, or it can refer to one battery cluster or at least two battery clusters connected in parallel; the photovoltaic string includes one photovoltaic module or at least two photovoltaic strings connected in series, and the battery cluster includes one battery pack or at least two battery packs connected in series; the setting of the DC power supply depends on its specific application environment and is not limited here.

[0050] The second side of the DC switch 101 is connected to the DC side of the power conversion module 102, and the AC side of the power conversion module 102 is connected to the first side of the AC switch 104 through the AC filter 103. The power conversion module 102 can adopt any topology of DC / AC conversion circuit in related technologies. Specifically, the DC / AC conversion circuit can be constructed using switching transistors such as IGBT (Insulated Gate Bipolar Transistor) and is controlled by a corresponding controller. The controller can be integrated into the power conversion module 102 or independent of the power conversion module 102, depending on the specific application environment, and is not limited here.

[0051] The second side of the AC switch 104 is connected to the power grid via the grid connection interface 105.

[0052] Figure 2 In the structure shown, each power conversion unit 10 in power conversion group 01 is connected in parallel to the grid connection interface 105, meaning that each power conversion unit 10 can be configured to share only the same grid connection interface 105. In practical applications, each power conversion unit 10 can also be configured to share the same AC switch 104 and the same grid connection interface 105. Figure 3The example shown uses power conversion group 01, which includes two power conversion units 10. Alternatively, each power conversion unit 10 can be configured to share the same AC filter 103, the same AC switch 104, and the same grid connection interface 105. Figure 4 The example shown uses power conversion group 01, which includes two power conversion units 10. The same logic applies to cases where power conversion group 01 includes more power conversion units 10; these will not be shown individually.

[0053] In other words, in practical applications, the power conversion units 10 within the same power conversion group 01 can adopt a shared hardware design on the AC side. For example, they can share a grid connection interface 105, or share an AC switch 104 and a grid connection interface 105, or share an AC filter 103, an AC switch 104, and a grid connection interface 105. This topology significantly reduces the number of components on the AC side, effectively reducing the hardware cost and size of the system. Furthermore, each power conversion group 01 can have its own corresponding grid connection interface 105, or they can share the same grid connection interface 105 to achieve grid connection, depending on the specific application environment, all of which are within the scope of this disclosure.

[0054] In the field of photovoltaic power generation, the DC power supply connected to the power conversion system is a photovoltaic string. Related technologies employ a direct-parallel control scheme, where multiple power conversion units are directly connected in parallel on the DC side, using a single MPPT (Maximum Power Point Tracking) control strategy. This is suitable for scenarios where the DC side shares a common bus. Under the direct-parallel control scheme, the control of the corresponding power conversion units is completely unified, leading to mutual interference between the two MPPT controls, preventing them from independently tracking the maximum power point. Especially in scenarios where the photovoltaic string is obstructed or experiences inconsistent aging, the maximum power points of the two MPPT controls may differ. The direct-parallel control scheme causes the two MPPT controls to operate in a suboptimal state, severely impacting inverter efficiency and system power generation. However, the power conversion system provided in this embodiment, when connected to a photovoltaic string as the DC power supply, allows each power conversion unit to perform independent MPPT, i.e., independently track the maximum power point of its respective photovoltaic string, maximizing energy harvesting efficiency and improving energy utilization efficiency.

[0055] Based on the above embodiments, in the power conversion group of the power conversion system, the slave unit within the group is configured to actively report the first operating information.

[0056] In other words, unlike the traditional passive polling mechanism, the slave devices in this embodiment adopt an active reporting mechanism, proactively uploading key operational information such as voltage, current, and fault status to the host device within the group. This active reporting mechanism can reduce communication latency and ensure that the host device can monitor the status of the slave devices in real time.

[0057] Based on the above embodiments, in the power conversion group of the power conversion system, the host in the group is further configured to synchronize the control state to the slave in the group.

[0058] In other words, the master unit within the group not only issues the first command but also synchronizes its control status with the slave units within the group, forcing the slave units to maintain consistent operating status with the master unit. The control status synchronized by the master unit to the slave units can include: transmission timing, power allocation, protection actions, and operating status. This master-slave follow-up strategy ensures a high degree of consistency in the operating status of the power conversion units within the group.

[0059] Inconsistent states among the power conversion units within a group can lead to problems such as abnormal voltage control and uneven power distribution under dynamic operating conditions, affecting the system's operational stability and reliability. This embodiment, through the aforementioned fine-grained state synchronization mechanism, effectively prevents problems such as increased circulating current, uneven device stress, and even power conversion module failure caused by inconsistent states among the power conversion units within the group, such as asynchronous switching timing. This significantly improves the reliability of parallel operation of the power conversion units within the group.

[0060] Furthermore, for the aforementioned power conversion system, if an independent control strategy is adopted—that is, each power conversion unit independently makes control decisions and controls PWM (Pulse Width Modulation) waveform generation based on its own collected electrical parameters—it can easily lead to the risk of bus voltage surge and module damage. Figure 2 Taking the structure shown as an example, since there is AC coupling between the two power conversion units 10, that is, there is a strong coupling relationship in electrical characteristics, if the scheme of independent control of each power conversion unit 10 is adopted, the waveform timing, duty cycle, phase and other parameters of the two power conversion units 10 may be different. This inconsistency in operating state will cause inrush current to be generated between the power conversion units 10 in the group, causing the bus voltage to rise. In severe cases, it will cause overvoltage damage to the power devices and damage to the module.

[0061] In this embodiment, the slave devices within the group collect their own initial operating information in real time and upload it to the master device within the group. The master device processes and analyzes the initial operating information of all power conversion units within the group in a unified manner, generates an initial instruction, and sends it to the slave devices within the group, while also synchronizing its own control status with the slave devices. That is, the master device within the group can coordinate and control the PWM waveform timing and duty cycle of all power conversion units within the group based on the unified decision results. In other words, the master device within the group makes unified decisions on key parameters such as waveform timing, duty cycle, and phase, ensuring that the power conversion units within the same group maintain synchronization in their operating status, avoiding inconsistencies in operating status caused by independent control strategies. In addition, synchronous waveform control can also eliminate circulating current between power conversion units within the group, effectively preventing bus voltage surge, avoiding overvoltage damage to power devices, and significantly reducing the risk of module damage.

[0062] This embodiment monitors the status of slave devices within the group in real time through the host system, promptly detecting and coordinating the handling of anomalies, thus avoiding system failures caused by single-machine protection. This strategy of unified control and status synchronization within the group can significantly improve the operational stability and reliability of the system.

[0063] In practical applications, the system master in this power conversion system is configured to: query the second operating information of each system slave, and issue a second instruction to each system slave when a preset local control strategy needs to be executed.

[0064] The second operational information refers to detailed operational information, which may include the first operational information mentioned above. It is not limited here and depends on the specific application environment.

[0065] In this embodiment, the system host acts as the main control unit of the entire system, communicating with each communication slave device to realize the issuance of system-level control commands and the aggregation of status information.

[0066] Furthermore, in this power conversion system, each power conversion group can communicate with each other through its own internal host. That is, the internal hosts of each group can be configured to communicate with the system, forming a three-level control system of system host - internal host - internal slave, which is conducive to achieving coordinated control of the entire system.

[0067] Based on the above embodiments, this embodiment provides some optional examples of the specific connection methods for the two-layer communication architecture in the power conversion system:

[0068] For example, different communication lines can be used for each layer of communication, such as... Figure 5 As shown, the intra-group communication between the host and slave units within the power conversion group 01, and the system communication between the system host and each system slave unit, are achieved using their respective communication lines. Figure 5The diagram only shows the controller 100 of each power conversion unit 10; the connection relationships of other structures can be found in the above embodiments. Furthermore, as shown above, the controller 100 can be integrated into the power conversion module of the corresponding power conversion unit 10 or can be independent of the corresponding power conversion module; no limitation is made here. Figure 5 The dashed lines in the diagram represent communication lines for intra-group communication, while the solid lines represent communication lines for system communication. In practical applications, communication lines for system communication can use communication buses, such as CAN (Controller Area Network) buses, but are not limited to these. Please refer to relevant technical documents for details.

[0069] In addition, intra-group communication and system communication can also adopt a physical layer multiplexing scheme, such as... Figure 6 As shown, the intra-group communication between the host and slave units within power conversion group 01, and the system communication between the system host and each system slave unit, share the first communication bus (e.g., Figure 6 The first CAN bus shown is CAN-1.

[0070] To achieve logical communication isolation and precise addressing on a shared communication bus, the communication protocol of the first communication bus can be reconfigured, for example:

[0071] (1) The mailboxes can be reassigned, that is, each power conversion unit 10 is assigned a corresponding mailbox to realize intra-group communication and system communication.

[0072] When the first communication bus is the CAN bus, the mailboxes for CAN communication of the controller are reassigned and redefined to distinguish the interactive data of intra-group communication and system communication.

[0073] (2) The communication within the group and the communication within the system can be identified by a specific ID (Identifier), that is, each power conversion unit 10 is assigned a corresponding ID to realize the communication within the group and the communication within the system.

[0074] When the primary communication bus is a CAN bus, the system can accurately identify whether the corresponding message comes from the group's master, group's slave, or the system master by parsing the ID field in the CAN message. This mechanism enables each power conversion unit in the group to achieve independent intra-group communication on the shared physical bus, ensuring real-time communication while avoiding signal conflicts.

[0075] In practical applications, the communication protocol of the first communication bus can be reconfigured using only one of the above methods, or both methods can be used simultaneously, depending on the specific application environment, and all of these methods are within the protection scope of this disclosure.

[0076] This embodiment achieves compatibility between individual master-slave communication within the group and system master-slave communication by reconstructing the architecture of the first communication bus. Specifically, the intra-group communication layer provides a direct communication channel between the power conversion units 10 within the group, enabling the master unit to obtain the first operating information of the slave units in real time and issue first commands to achieve coordinated control. The two-layer communication architecture is rationally designed, and the communication timing is scientifically designed, ensuring the real-time performance and reliability of the control.

[0077] Moreover, this embodiment can reconstruct the communication architecture based on the communication bus that enables system communication, without increasing the cost of additional hardware design. It only requires software upgrades, that is, reconfiguring the communication protocol as described above, to achieve the integration of intra-group communication and system communication.

[0078] Furthermore, the modular design of the communication and control schemes provided in this embodiment facilitates independent development and testing. The two-layer communication architecture offers excellent scalability and can adapt to systems with varying numbers of parallel devices. The collaborative control strategy algorithm is clear and easy to implement and debug in engineering. Experimental verification demonstrates the good engineering applicability of this embodiment.

[0079] Based on the above embodiments, the power conversion system may further include, for example, Figure 7 (in) Figure 6 (Based on the situation shown in the example) As shown: System controller 20; The system controller 20 can specifically adopt an ARM (Advanced RISC Machines) controller, and each controller in each power conversion unit 10 can adopt a DSP (Digital Signal Processor), but in actual applications it is not limited to this.

[0080] The system controller 20 and each power conversion unit 10 are connected to each other via a second communication bus; the second communication bus can also be a CAN bus, and is not limited to this in practical applications.

[0081] The system controller 20 is configured to: query the third operating information of each power conversion unit 10; receive a global scheduling instruction; and generate and issue at least one of a power setting instruction and a start / stop control instruction to each power conversion unit 10. This third operating information refers to operating status information, which may be the same as the second operating information described above, but is not limited to it.

[0082] like Figure 7 As shown in the figure, this embodiment adopts a hierarchical multi-machine communication architecture. This architecture is based on the system controller 20 as the host computer, and a dual-bus communication network is constructed. Among them, the second communication bus (i.e., Figure 7 The CAN-2 shown in the diagram serves as the upper-level control bus, and the first communication bus (i.e.) Figure 7 The CAN-1 shown in the figure serves as the underlying interaction bus.

[0083] Specifically, the system controller 20 communicates via the second communication bus (i.e., Figure 7 The system controller 20 (CAN-2) establishes a communication connection with all power conversion units 10 within the system. In this link, the system controller 20 acts as the master node, using a polling mechanism to periodically query the operating status information of each power conversion unit 10. Simultaneously, the system controller 20 is responsible for receiving global scheduling commands from the site control center and communicating via the second communication bus (i.e., CAN-2). Figure 7 The CAN-2 shown in the figure sends power setting, start-stop control and other commands to each power conversion unit 10 in the system to realize centralized management at the system level.

[0084] Additionally, all power conversion units 10 within the system can be configured to communicate via the first communication bus (i.e., Figure 7 The CAN-1 units shown are interconnected to form a local communication network. In this network, one power conversion unit 10 is designated as the system master, and the remaining power conversion units 10 act as system slaves. The system master is responsible for communicating via the first communication bus (i.e., Figure 7 The CAN-1 shown queries detailed operating information of all power conversion units 10 in the system and determines whether a specific local control strategy needs to be executed based on preset logic. Once it is determined that a local control strategy needs to be executed, the system host will directly communicate via the first communication bus (i.e., Figure 7 The CAN-1 shown in the figure sends corresponding control commands to each power conversion unit 10, thereby achieving fast local response without relying on the host computer.

[0085] This embodiment, based on hardware sharing for grouping, utilizes a two-layer bus architecture, intra-group master-slave collaborative control, and software configuration to achieve a low-cost, highly reliable, and efficient multi-machine control system.

[0086] Similar or identical parts between the various embodiments in this disclosure can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment solution according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0087] Those skilled in the art will also recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this disclosure.

[0088] The above description of the disclosed embodiments shows that the features described in the various embodiments of this disclosure can be substituted for or combined with each other, enabling those skilled in the art to implement or use this disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power conversion system, characterized in that, include: At least two power conversion groups, each power conversion group comprising: at least two power conversion units connected in parallel on their AC sides; wherein... In the power conversion group, each power conversion unit is communicatively connected, wherein one power conversion unit acts as the master unit within the group, and the other power conversion units act as slave units within the group. The host in the group is configured to: make logical judgments based on the first operating information of the slave in the group, determine and issue corresponding first instructions to the slave in the group; Each power conversion group is connected to the system through at least one of its power conversion units, wherein one power conversion unit acts as the system master and the other power conversion units act as system slaves.

2. The power conversion system according to claim 1, characterized in that, The host machine within the group is also configured to synchronize the control status to the slave machines within the group.

3. The power conversion system according to claim 1, characterized in that, In the power conversion group, the slave unit within the group is configured to actively report the first operating information.

4. The power conversion system according to claim 1, characterized in that, The system host is configured to: query the second operating information of each of the system slaves, and, when a preset local control strategy needs to be executed, issue a second instruction to each of the system slaves.

5. The power conversion system according to claim 1, characterized in that, Each of the power conversion groups communicates with each other through its respective host computer within the group.

6. The power conversion system according to any one of claims 1 to 5, characterized in that, The intra-group communication between the host and slave devices within the power conversion group, and the system communication between the system host and each of the system slave devices, share a first communication bus.

7. The power conversion system according to claim 6, characterized in that, Each of the power conversion units is assigned a corresponding mailbox for implementing intra-group communication and system communication.

8. The power conversion system according to claim 6, characterized in that, Each of the power conversion units is assigned a corresponding identifier to implement the intra-group communication and the system communication.

9. The power conversion system according to any one of claims 1 to 5, characterized in that, The intra-group communication between the host and slave units within the power conversion group, and the system communication between the system host and each of the system slave units, are implemented using their respective corresponding communication lines.

10. The power conversion system according to any one of claims 1 to 5, characterized in that, The power conversion system further includes: a system controller; The system controller and each of the power conversion units are connected via a second communication bus; The system controller is configured to: query the third operating information of each of the power conversion units; receive a global scheduling instruction; and generate and issue at least one of a power setting instruction and a start / stop control instruction to each of the power conversion units.

11. The power conversion system according to any one of claims 1 to 5, characterized in that, The power conversion unit includes: a DC switch, a power conversion module, an AC filter, and an AC switch; The first side of the DC switch is used to connect a DC power supply. The second side of the DC switch is connected to the DC side of the power conversion module; The AC side of the power conversion module is connected to the first side of the AC switch via the AC filter; The second side of the AC switch is connected to the power grid via a grid connection interface.

12. The power conversion system according to claim 11, characterized in that, In the power conversion group: Each of the power conversion units is connected in parallel to the grid interface; Alternatively, each of the power conversion units may share the same AC switch and the grid connection interface; Alternatively, each of the power conversion units may share the same AC filter, the same AC switch, and the same grid connection interface.

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