Parallel connection system and control method thereof

Abstract

The application provides a parallel system and a control method thereof. The parallel system comprises at least two parallel subsystems, wherein each of the parallel subsystems comprises at least one electric energy conversion device, each of the electric energy conversion devices comprises two communication interfaces; two of the communication interfaces in any of the parallel subsystems are defined as BSC interfaces, and the other communication interfaces are defined as parallel communication interfaces; the parallel communication interfaces of the electric energy conversion devices in the same parallel subsystem are sequentially connected by a communication cable; and the BSC interfaces of the at least two parallel subsystems are sequentially connected by a communication cable. When there are more than one electric energy conversion device in the parallel subsystem, the two BSC interfaces are located on different electric energy conversion devices respectively.

Description

Technical Field

[0001] This application relates to power system communication technology, and more particularly to a parallel system and its control method. Background Technology

[0002] Currently, multiple Uninterruptible Power Supply (UPS) units can be configured into parallel systems or dual-bus systems. To accommodate both systems, each UPS includes two parallel communication interfaces and a Bus Synchronization Controller (BSC) interface. In existing technology, a single UPS typically has two parallel communication ports and two BSC interfaces. When a parallel system is required in the scenario, the parallel communication ports are used; when a dual-bus system is required, the BSC interfaces are used. While this design satisfies the wiring requirements of both systems, it necessitates multiple connection ports on the UPS. This not only increases space requirements and costs but also complicates wiring in the parallel system, increases the likelihood of wiring errors, and raises integration and maintenance costs. Summary of the Invention

[0003] This application provides a parallel system and its control method, which can reduce wiring complexity and maintenance costs.

[0004] The technical solution of this application embodiment is implemented as follows: In a first aspect, embodiments of this application provide a parallel system, comprising: at least two parallel subsystems, each parallel subsystem including at least one power conversion device, each power conversion device including two communication interfaces; two of the communication interfaces within any parallel subsystem are defined as BSC interfaces, and the other communication interfaces are defined as parallel communication interfaces; the power conversion devices within the same parallel subsystem are sequentially connected to each other via communication cables, and the BSC interfaces between at least two parallel subsystems are sequentially connected via communication cables; wherein, when there is more than one power conversion device in the parallel subsystem, the two BSC interfaces are located on different power conversion devices.

[0005] In the above scheme, both the parallel communication interface and the BSC interface follow the Controller Area Network (CAN) communication protocol for data transmission.

[0006] In the above scheme, at least one parallel subsystem includes a first parallel subsystem and a second parallel subsystem. The first parallel subsystem includes a first power conversion device and a second power conversion device. The second parallel subsystem includes a third power conversion device and a fourth power conversion device. The first communication interfaces of the first, second, third, and fourth power conversion devices are all configured as parallel communication interfaces. The second communication interfaces of the first, second, third, and fourth power conversion devices are all configured as BSC interfaces. The first communication interface of the first power conversion device is connected to the first communication interface of the second power conversion device via a first communication cable. The first communication interface of the third power conversion device is connected to the first communication interface of the fourth power conversion device via a second communication cable. The second communication interface of the first power conversion device is connected to the second communication interface of the fourth power conversion device via a third communication cable. The second communication interface of the second power conversion device is connected to the second communication interface of the third power conversion device via a fourth communication cable.

[0007] In the above scheme, the power conversion equipment is an uninterruptible power supply.

[0008] Secondly, embodiments of this application provide a control method for a parallel subsystem, wherein the parallel subsystem is any one of the parallel subsystems described in any of the aforementioned parallel systems, and at least two communication cables in the parallel system are disconnected; the method includes: determining a disconnection event of the current parallel subsystem based on the disconnection status of the parallel system; wherein the current parallel subsystem in the parallel system is defined as the local subsystem, and all other parallel subsystems besides the local subsystem are defined as other subsystems; when a communication cable connected to a parallel communication interface in the local subsystem is disconnected, it is marked as a first flag; when a communication cable connected to a BSC interface in the local subsystem is disconnected, or when a communication cable connected to a parallel communication interface or BSC interface in any other subsystem is disconnected, it is marked as a second flag; the disconnection events in which at least two communication cables in the local subsystem are disconnected are respectively a first event including the first flag and the second flag, a second event including only the first flag, and a third event including only the second flag; controlling the operating state of the current parallel subsystem according to the disconnection event, wherein when the disconnection event is the third event, the local subsystem operates in a first state; when the disconnection event is the first event or the second event, the local subsystem operates in a second state.

[0009] In the above scheme, the power conversion equipment is an uninterruptible power supply. The first state is the inverter operation state, and the second state is the operation state of being connected to the mains power via a bypass.

[0010] In the above scheme, the method further includes: when the potential of the parallel communication interface contained in the local subsystem is detected to be at a preset potential, determining that the communication cable connected to the parallel communication interface in the local subsystem is disconnected; and / or, when the potential of the BSC interface contained in the local subsystem or another subsystem is detected to be at a preset potential, determining that the communication cable connected to the BSC interface in the local subsystem or another subsystem is disconnected.

[0011] In the above scheme, the method also includes: disconnecting the communication cable connected to the parallel communication interface or BSC interface of the other subsystem obtained through the controller area network CAN communication protocol.

[0012] Thirdly, embodiments of this application provide a control method for a power conversion device, wherein the power conversion device is any one in a parallel system, the parallel system is any of the aforementioned parallel systems, and at least two communication cables in the parallel system are disconnected; the method includes: determining a disconnection event of the power conversion device based on the disconnection status of the current parallel system to which the power conversion device is located; wherein, the current parallel subsystem to which the power conversion device is located is defined as the local subsystem, and other parallel subsystems besides the local subsystem are defined as other subsystems; when a communication cable connected to a parallel communication interface in the local subsystem is disconnected, it is marked as a first flag; when the local subsystem... When a communication cable connected to a BSC interface is disconnected, or when a communication cable connected to a parallel communication interface or BSC interface in another subsystem is disconnected, this is recorded as the second flag. Disconnection events where at least two communication cables in the local subsystem are disconnected are categorized as a first event containing both the first and second flags, a second event containing only the first flag, and a third event containing only the second flag. The operating state of the current power conversion equipment is controlled based on the disconnection event. Specifically, when the disconnection event is the third event, the current power conversion equipment operates in the first state; when the disconnection event is either the first or second event, the current power conversion equipment operates in the second state.

[0013] In the above scheme, the power conversion equipment is an uninterruptible power supply. The first state is the inverter operation state, and the second state is the operation state of being connected to the mains power via a bypass.

[0014] The embodiments of this application have the following beneficial effects: In a parallel system, each power conversion device only needs to be configured with two interfaces, eliminating the need for additional redundant interfaces. Power conversion devices within the same parallel subsystem are sequentially connected via parallel communication interfaces, and different parallel subsystems are sequentially connected via BSC interfaces, thereby constructing a complete communication loop. This method reduces the number of interfaces and the number of communication cables required for connecting these interfaces, improving the integration of the parallel system and reducing wiring complexity and maintenance costs. Furthermore, it enables redundant design, improving the reliability of the parallel system. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the parallel system provided in the embodiments of this application; Figure 2 This is an exemplary structural diagram of the parallel system provided in the embodiments of this application. Figure 1 ; Figure 3 This is an exemplary structural diagram of the parallel system provided in the embodiments of this application. Figure 2 ; Figure 4 This is an exemplary structural diagram of the parallel system provided in the embodiments of this application. Figure 3 ; Figure 5 yes Figure 2 A schematic diagram of the disconnection detection circuit for the provided parallel system; Figure 6 This is a schematic flowchart of the control method for the power conversion equipment provided in the embodiments of this application; Figure 7 This is an exemplary structural diagram of the parallel system provided in the embodiments of this application. Figure 4 .

[0016] It should be noted that the terms "first" and "second" mentioned above are only used to distinguish between different options and do not represent the degree of superiority or inferiority of the options or their priority in the implementation process. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the application will be further described in detail below with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] As mentioned above, each power conversion device needs to be configured with two parallel communication interfaces and two BSC interfaces, resulting in interface redundancy and complex wiring.

[0019] To address the aforementioned problems, this application provides a parallel operation system and its control method. The parallel operation system may include at least two parallel operation subsystems, each subsystem including at least one power conversion device, and each power conversion device including two communication interfaces. Two of the communication interfaces within any parallel operation subsystem are defined as BSC interfaces, and the other communication interfaces are defined as parallel communication interfaces. Power conversion devices within the same parallel operation subsystem are sequentially connected to each other via communication cables, and the BSC interfaces between at least two parallel operation subsystems are sequentially connected via communication cables. When there is more than one power conversion device in a parallel operation subsystem, the two BSC interfaces are located on different power conversion devices. Therefore, by providing two communication interfaces for each power conversion device in the parallel operation system, and sequentially connecting the corresponding parallel communication interfaces within the same parallel operation subsystem, and sequentially connecting different parallel operation subsystems via BSC interfaces, redundant communication loops are formed, reducing the number of interfaces, lowering wiring complexity, and improving the operational reliability of the parallel operation system.

[0020] Specifically, the following is in conjunction with the appendix Figures 1 to 7 The various embodiments described herein are used to illustrate the technical solutions of the present invention in detail.

[0021] See Figure 1 This illustrates a schematic diagram of the parallel system provided in an embodiment of this application. Figure 1 As shown, the parallel system 10 may include at least two parallel subsystems 100, wherein each parallel subsystem 100 may include at least one power conversion device 101, and each power conversion device 101 may include two communication interfaces, as shown below. Figure 1 The interface shown can be referred to as the first communication interface 1011 and the second communication interface 1012, respectively.

[0022] It should be noted that the two power supply devices can form a parallel system or a dual-bus system. A parallel system 10 refers to a system in which the outputs of two or more power conversion devices 101 of the same model and capacity are connected in parallel via a parallel cabinet or directly to jointly provide energy to the load. Its core purpose is to provide a higher level of reliability, availability, and expansion flexibility, far exceeding the capacity of a single power conversion device 101. A dual-bus system refers to two power conversion devices 101 (or parallel subsystems 100) connected through their respective BSC interfaces to form two independent power supply buses, eliminating all single points of failure from input to load and improving availability. Power conversion device 101 can refer to a device used for power regulation, energy storage, and release, typically integrating components such as inverters, battery banks, and control modules. In some embodiments, power conversion device 101 can be a UPS.

[0023] In this embodiment of the application, among the communication interfaces of each power conversion device 101 within any parallel subsystem 100 of the aforementioned parallel system 10, only two communication interfaces can be defined as BSC interfaces, while the other communication interfaces are defined as parallel communication interfaces. Furthermore, when there is more than one power conversion device 101 in the parallel subsystem 100, the two BSC interfaces in the parallel subsystem 100 must be located on different power conversion devices 101. Under this rule, the parallel communication interfaces of each power conversion device 101 in the same parallel subsystem 100 are sequentially connected via communication cables. At least two parallel subsystems 100 are sequentially connected via communication cables to form redundant communication loops. That is, among the first communication interface 1011 and second communication interface 1012 included in each power conversion device 101 in the same parallel subsystem 100, only two communication interfaces are defined as BSC interfaces, while the other communication interfaces are defined as parallel communication interfaces. Furthermore, when the same parallel subsystem 100 includes more than one power conversion device 101, the two communication interfaces defined as BSC interfaces are located on different power conversion devices 101.

[0024] It is understandable that within the same parallel subsystem 100, connecting the parallel communication interfaces of two power conversion devices 101 via a communication cable enables parallel operation between these two devices. This allows them to work collaboratively, balance the load, and maintain consistency in parameters such as voltage and frequency through a communication protocol (e.g., CAN protocol). In different parallel subsystems 100, connecting different BSC interfaces via a communication cable allows for bus synchronization between the two subsystems through a communication protocol. This coordinates the output bus phase relationship between the two subsystems, preventing power imbalance or system instability caused by phase inconsistencies, and enabling stable operation of the two subsystems 100 in a dual-bus structure. It is understood that both the parallel communication interface and the BSC interface use communication protocols for data transmission, but the output data differs.

[0025] Based on the aforementioned interface definitions and circuit connection rules, an example of a parallel system 10 is as follows: Figure 2As shown, at least two parallel subsystems 100 may include a first parallel subsystem 201 and a second parallel subsystem 202. The first parallel subsystem 201 may include a first power conversion device 2011 and a second power conversion device 2012, and the second parallel subsystem 202 may include a third power conversion device 2021 and a fourth power conversion device 2022. The first communication interface 1011 of the first power conversion device 2011, the second power conversion device 2012, the third power conversion device 2013, and the fourth power conversion device 2014 is configured as a parallel communication interface; the second communication interface 1012 of the first power conversion device 2011, the second power conversion device 2012, the third power conversion device 2013, and the fourth power conversion device 2014 is configured as a BSC interface. Based on this, the first communication interface 1011 of the first power conversion device 2011 is connected to the first communication interface 1011 of the second power conversion device 2012 via the first communication cable 203; the first communication interface 1011 of the third power conversion device 2021 is connected to the first communication interface 1011 of the fourth power conversion device 2022 via the second communication cable 204; the second communication interface 1012 of the first power conversion device 2011 is connected to the second communication interface 1012 of the fourth power conversion device 2022 via the third communication cable 205; and the second communication interface 1012 of the second power conversion device 2012 is connected to the second communication interface 1012 of the third power conversion device 2021 via the fourth communication cable 206.

[0026] It should be noted that, Figure 2 The parallel system shown is the one described above. Figure 1This is a specific example of a parallel system. The parallel system 10 includes two parallel subsystems: a first parallel subsystem 201 and a second parallel subsystem 202. The first parallel subsystem 201 includes a first power conversion device 2011 and a second power conversion device 2012, and the second parallel subsystem 202 includes a third power conversion device 2021 and a fourth power conversion device 2022. The two communication interfaces of these four power conversion devices are defined as follows: the first communication interface 1011 is defined as a parallel communication interface, and the second communication interface is defined as a BSC interface. Based on this communication interface definition, the connection relationship of the four power conversion devices 101 is as follows: the first communication interface 1011 of the first power conversion device 2011 is connected to the first communication interface 1011 of the second power conversion device 2012 through the first communication cable 203; the first communication interface 1011 of the third power conversion device 2021 is connected to the first communication interface 1011 of the fourth power conversion device 2022 through the second communication cable 204; the second communication interface 1012 of the first power conversion device 2011 is connected to the second communication interface 1012 of the fourth power conversion device 2022 through the third communication cable 205; and the second communication interface 1012 of the second power conversion device 2012 is connected to the second communication interface 1012 of the third power conversion device 2021 through the fourth communication cable 206. In this way, the parallel communication interfaces of the first power conversion device 2011 and the second power conversion device 2012 in the first parallel subsystem 201 are connected in sequence, the parallel communication interfaces of the third power conversion device 2013 and the fourth power conversion device 2014 in the second parallel subsystem 202 are connected in sequence, and the BSC interfaces included in the first parallel subsystem 201 and the second parallel subsystem 202 are connected in sequence. Moreover, the number of power conversion devices 101 included in the first parallel subsystem 201 and the second parallel subsystem 202 is greater than 1. Therefore, the BSC interfaces in these two parallel subsystems 100 are defined on two different power conversion devices 101.

[0027] In some embodiments, the first communication cable 203, the second communication cable 204, the third communication cable 205, and the fourth communication cable 206 can all be CAN communication cables.

[0028] Another example of a parallel system 10, such as Figure 3As shown, the parallel system 10 includes two parallel subsystems, namely a first parallel subsystem 201 and a second parallel subsystem 202. The first parallel subsystem 201 includes a first power conversion device 2011, and the second parallel subsystem 202 includes a third power conversion device 2021. The first communication interface 1011 of the first power conversion device 2011 is connected to the first communication interface 1011 of the third power conversion device 2021, and the second communication interface 1012 of the first power conversion device 2011 is connected to the first communication interface 1012 of the third power conversion device 2021. The difference from the previous embodiment is that in this embodiment, each parallel subsystem includes only one power conversion device. Therefore, the two communication interfaces of each power conversion device are defined as BCS interfaces. That is, the first communication interface 1011 and the second communication interface 1012 of the first power conversion device 2011 and the first communication interface 1011 and the second communication interface 1012 of the third power conversion device 2021 are both BCS interfaces, thus forming a dual-bus system with only a single machine.

[0029] Another example of a parallel system 10, such as Figure 4 As shown, at least two parallel subsystems 100 may include: a third parallel subsystem 301, a fourth parallel subsystem 302, and a fifth parallel subsystem 303. Each parallel subsystem includes three power conversion devices. Specifically, the third parallel subsystem 301 may include power conversion devices 3011 to 3013; the fourth parallel subsystem 302 may include a seventh power conversion device 3021, an eighth power conversion device 3022, and a ninth power conversion device 3023; and the fifth parallel subsystem 303 may include power conversion devices 3031 to 3033. According to the aforementioned communication interface definitions and connection rules, in one possible implementation, the second communication interface of the first power conversion device and the second communication interface of the last power conversion device in each parallel subsystem are both defined as BSC interfaces, and the other communication interfaces within the parallel subsystem are defined as parallel communication interfaces. Taking the fourth parallel subsystem 302 as an example, the first communication interface 1011 of the seventh power conversion device 3021 is defined as a parallel communication interface, and the second communication interface 1012 is defined as a BSC interface. The first communication interface 1011 and the second communication interface 1012 of the eighth power conversion device 3022 are both defined as parallel communication interfaces. The first communication interface 1011 of the ninth power conversion device 3023 is defined as a parallel communication interface, and the second communication interface 1012 is defined as a BSC interface. That is, the parallel communication interfaces in the power conversion devices of each parallel subsystem are connected sequentially, and the BSC interfaces contained in the third parallel subsystem 301, the fourth parallel subsystem 302, and the fifth parallel subsystem 303 are connected sequentially.

[0030] In the above embodiments, the parallel subsystem includes three power conversion devices as an example. In other embodiments, there can be any number of power conversion devices. Similarly, it can be extended to any number of parallel subsystems.

[0031] It should be understood that, Figures 2 to 4 The parallel system shown is merely an example to illustrate the parallel system of this application. In this application, the first communication interface 1011 and the second communication interface 1012 in each power conversion device 101 are not different before configuration. In other words, the first communication interface 1011 and the second communication interface can be the same type of interface before configuration. Configuration is only performed as needed when the power conversion device 101 is applied to the parallel subsystem 100 and the parallel system 10. For specific examples, please refer to the foregoing. Figures 2 to 4In other words, the first communication interface 1011 of each power conversion device can be configured as a parallel communication interface or a BSC interface, and the second communication interface 1012 can be configured as a parallel communication interface or a BSC interface. Specific configurations can be selected according to actual conditions. Some configurations are shown in Table 1 below. Here, A indicates that the interface of the power conversion device is configured as a parallel communication interface, and B indicates that the interface of the power conversion device is configured as a BSC interface. In this case, the two-machine parallel system can refer to the parallel system 10 including a parallel subsystem 100, which contains two power conversion devices, and the first and second communication interfaces of each power conversion device are configured as parallel communication interfaces. For example, as shown in Table 1, the first and second communication interfaces of UPS1 and UPS2 are both configured as parallel communication interfaces, that is, the interface bits of UPS1 and UPS2 are both defined as A and A. In this two-machine parallel system, UPS1 and UPS2 can, for example, be connected through their respective first communication interfaces 1011 and their respective second communication interfaces to form a redundant parallel subsystem 100. A two-unit BSC system can refer to a parallel system 10 comprising two parallel subsystems 100, each containing one power conversion device. For example, UPS1 is one parallel subsystem, and UPS2 is another. Both subsystems have their first and second communication interfaces configured as BSC interfaces, and they form a redundant dual-bus parallel system through the connection of their respective first and second communication interfaces. A three-unit parallel system can refer to a parallel system 10 comprising one parallel subsystem 100 containing three power conversion devices, such as UPS1, UPS2, and UPS3. The specific interface definitions and connection methods can be designed according to the previous descriptions. A two-unit parallel BSC system can refer to a parallel system 10 comprising two parallel subsystems 100, where one subsystem 100 contains two power conversion devices 101, and the other subsystem 100 contains one power conversion device. The specific interface definitions can be found in Table 1, and the connection methods can be designed according to the previous descriptions, which will not be repeated here. The four-machine parallel system includes a parallel subsystem 100, which contains four power conversion devices 101. Two interfaces of each power conversion device are configured as parallel communication interfaces, and the connection method can refer to the aforementioned design. The connection method of the two-parallel + dual-bus system can be as follows: Figure 2 As shown.

[0032] Table 1

[0033] In summary, the interface bit definition rules for each power conversion device in the parallel system of this application stipulate that only two B interfaces are connected between BSC systems, while A interfaces are connected within the parallel system. Furthermore, the host computer can configure the interfaces in the power conversion devices to achieve different types of parallel systems.

[0034] In some embodiments, see reference as follows Figure 2 The parallel system 10 includes four power conversion devices 101, any one of which can detect whether the first communication cable 203 or the second communication cable 204 connected to it is disconnected. Specifically, taking the detection of the first power conversion device 2011 as an example, such as... Figure 5 As shown, it illustrates Figure 2 The parallel system shown includes a detection circuit for the first communication cable 203 connecting the first power conversion device 2011 and the second power conversion device 2012 to the first communication interface 1011. R1 and D1 are a resistor and diode in the first power conversion device 2011, respectively, and R2 and D2 are a resistor and diode in the second power conversion device 2012, respectively. When the first communication cable 203 is disconnected, the potential of the first communication interface 1011 of both the first power conversion device 2011 and the second power conversion device 2012 is high. That is, the first power conversion device 2011 may include a controller 1. This controller 1, upon detecting that the potential of the first communication interface 1011 of the first power conversion device 2011 is a preset potential (e.g., high potential), determines that the first communication cable 203 connecting the first power conversion device 2011 and the second power conversion device 2012 to the first communication interface 1011 is disconnected. Furthermore, the first power conversion device 2011 broadcasts to the fourth power conversion device 2022 via its second communication interface 1012 and third communication cable 205 that the first communication cable 203 connecting the first power conversion device 2011 and the second power conversion device 2012 to the first communication interface 1011 is disconnected. The fourth power conversion device 2022 broadcasts to the third power conversion device 2021 via its first communication interface 1011 and second power conversion device 204 that the first communication cable 203 connecting the first power conversion device 2011 and the second power conversion device 2012 to the first communication interface 1011 is disconnected. The controller 2 in the second power conversion device 2012 can also detect that the first communication cable 203 connecting the first power conversion device 2011 and the second power conversion device 2012 to the first communication interface 1011 is disconnected. In general, when the connection line of any interface of any power conversion device 101 in the parallel system 10 is disconnected, the local unit (power conversion device 101 itself) can detect which interface connection line is disconnected, and can quickly inform other power conversion devices 101 in the entire parallel system 10 of the disconnection status through the connection lines of other interfaces.

[0035] Furthermore, from a redundancy perspective, taking the first power conversion device 101 as an example, the first communication cable 203 connected to the first communication interface 1011 of the first power conversion device 101 and the third communication cable 205, second communication cable 204, and fourth communication cable 206 connected to the second communication interface 1012 of the first power conversion device 101 are redundant. In other words, if the first communication cable 203 is disconnected, the second power conversion device 2012 and the first power conversion device 2011 can still communicate through the third communication cable 205, second communication cable 204, and fourth communication cable 206 to maintain normal parallel operation. Therefore, according to the aforementioned interface definition and circuit connection rules... Figures 2 to 4 The parallel system 10 shown can not only reduce the number of interfaces and the complexity of wiring, but also improve the reliability of the parallel system operation.

[0036] Based on the aforementioned parallel system, such as Figure 6 As shown, this application embodiment also provides a control method for a parallel subsystem. The parallel subsystem 100 can be any of the parallel systems 10 described above, and at least two communication cables in the parallel system are disconnected. The method includes steps 501 and 502.

[0037] Step 501: Determine the disconnection event of the current parallel subsystem based on the disconnection status of the parallel system; wherein, the current parallel subsystem in the parallel system is defined as the local subsystem, and all other parallel subsystems are defined as other subsystems; when the communication cable connected to the parallel communication interface in the local subsystem is disconnected, it is marked as the first flag; when the communication cable connected to the BSC interface in the local subsystem is disconnected, or when the communication cable connected to the parallel communication interface or BSC interface in any other subsystem is disconnected, it is marked as the second flag; the disconnection event in which at least two communication cables in the local subsystem are disconnected is respectively the first event containing the first flag and the second flag, the second event containing only the first flag, and the third event containing only the second flag.

[0038] Step 502: Control the current operating state of the parallel subsystem according to the disconnection event. When the disconnection event is the third event, the local subsystem operates in the first state; when the disconnection event is the first event or the second event, the local subsystem operates in the second state.

[0039] It should be noted that the above control method is for controlling the operating state of any parallel subsystem in the parallel system 10. In practice, at least one power conversion device 101 in the parallel subsystem 100 operates in parallel. If two power conversion devices 101 cannot communicate with each other, all power conversion devices in that parallel subsystem need to simultaneously transition from the first state to the second state. However, the inability to communicate between two parallel subsystems 100 does not affect the operating state of the power conversion devices 101 included in the parallel subsystem 100. In other words, even when two parallel subsystems 100 cannot communicate, the operating state of the power conversion devices 101 included in the two related parallel subsystems 100 can still remain in the first state.

[0040] Therefore, for each parallel subsystem 100, the first step is to set a corresponding disconnection event for the local subsystem based on the disconnection status of the parallel system. Then, the operating status of each power conversion device in the local subsystem is controlled according to the disconnection event. Specifically, the principle for setting the corresponding disconnection event for the local subsystem based on the disconnection status of the parallel system is as follows: when a communication cable connected to a parallel communication interface in the local subsystem is disconnected, this is recorded as the first flag, for example, ... Figure 2 In the parallel system shown, a first flag is set when the first communication cable 203 of the first power conversion device 2011 is disconnected. A second flag is set when a communication cable connected to a BSC interface in the local subsystem is disconnected, or when a communication cable connected to a parallel communication interface or BSC interface in any other subsystem is disconnected. For example... Figure 2 In the parallel system shown, a second flag is recorded when at least one of the third communication cable 205, the second communication cable 204, and the fourth communication cable 206 in the local subsystem is disconnected. Subsequently, determining a disconnection event in which at least two communication cables in the local subsystem are disconnected includes: a first event containing both the first and second flags, a second event containing only the first flag, and a third event containing only the second flag. Then, the operating state of the current parallel subsystem is controlled according to the disconnection event. Specifically, when the disconnection event is the third event, the local subsystem operates in the first state; when the disconnection event is either the first or the second event, the local subsystem operates in the second state. In some embodiments, the power conversion device 101 can be an uninterruptible power supply (UPS), the first state can be an inverter operation state, and the second state can be an operation state with bypass access to mains power.

[0041] In some embodiments, the method may further include: determining that a communication cable connected to a parallel communication interface in the local subsystem is disconnected when the potential of the parallel communication interface in the local subsystem is detected to be at a preset potential; and / or determining that a communication cable connected to a BSC interface in the local subsystem or another subsystem is disconnected when the potential of the BSC interface in the local subsystem or another subsystem is detected to be at a preset potential. The preset potential may be as follows: Figure 4 The high potential shown. For specific testing, please refer to the aforementioned [measurement / testing]. Figure 4 The description will not be repeated here.

[0042] In some embodiments, the method may further include: obtaining information about the disconnection of the communication cable connected to the parallel communication interface or BSC interface of another subsystem via the Controller Area Network (CAN) communication protocol. That is, even if the connection line of the power conversion device 101 in the local subsystem is not disconnected, it can receive information from other power conversion devices 101 regarding the disconnection of their corresponding connection lines.

[0043] For example, regarding the control methods described above, such as... Figure 7 The parallel system shown assumes that the power conversion device 101 is a UPS. The parallel system may include a first parallel subsystem 201 and a second parallel subsystem 202. The first parallel subsystem 201 includes a first power conversion device 2011 and a second power conversion device 2012. The second parallel subsystem 202 includes a third power conversion device 2021 and a fourth power conversion device 2022. In this case, the first power conversion device 2011 is UPS1, the second power conversion device 2012 is UPS2, the third power conversion device 2021 is UPS3, the fourth power conversion device 2022 is UPS4, and the first communication cable 203 is line 1, the second communication cable 204 is line 3, the third communication cable 205 is line 4, and the fourth communication cable 206 is line 2. Taking the first parallel subsystem 201 as an example, when line 1 connected to the first power conversion device 2011 is disconnected, it is denoted as 'a' (an example of a first indicator); the remaining disconnections, such as at least one of the third communication cable 205, the second communication cable 204, and the fourth communication cable 206, are all denoted as 'b' (an example of a second indicator). Therefore, the disconnection events included in the first parallel subsystem 201 can include: a first event containing both 'a' and 'b', a second event containing only 'a', and a third event containing only 'b'. In this case, only when the disconnection event is the third event does each power conversion device in the first parallel subsystem 201 operate in the first state; while when the disconnection event is either the first or the second event, each power conversion device in the first parallel subsystem operates in the second state. This will be explained specifically using operating conditions 1 to 4 below as examples.

[0044] Condition 1: Line 4 disconnects. UPS1 and UPS4 can detect the disconnection of line 4 themselves. UPS2 / 3 can receive disconnection notifications from UPS1 and UPS4. At this time, there is no disconnection of the communication cable connecting the parallel communication interface for either the first parallel subsystem 201 or the second parallel subsystem 202. Both parallel subsystems are recorded as b, and consequently, all power conversion equipment records b. Condition 2: Line 2 disconnects. UPS2 and UPS3 can detect the disconnection of line 2 themselves. UPS1 / 4 can receive disconnection notifications from UPS2 and UPS4. At this time, UPS2 / 3 can detect the disconnection of line 4 themselves. Both parallel subsystems are recorded as b again, and consequently, all power conversion equipment records b again. The specific details of the disconnection events for each parallel subsystem are shown in Table 2 below.

[0045] Table 2

[0046] At this time, the disconnection events of the first parallel subsystem 201 and the second parallel subsystem 202 both include the third event. Therefore, UPS1 to UPS4 can all maintain inverter operation without switching to bypass operation.

[0047] Condition 2: Line 4 disconnected. UPS1 and UPS4 can detect the disconnection of line 4. UPS2 / 3 can receive disconnection notifications from UPS1 and UPS4. At this time, there is no disconnection of the communication cable connecting the parallel communication interface for either the first parallel subsystem 201 or the second parallel subsystem 202. Both parallel subsystems are recorded as b. Consequently, all power conversion equipment is recorded as b. Line 1 disconnected. UPS1 and UPS2 can detect the disconnection of line 1. UPS3 and UPS4 can receive disconnection notifications from UPS1 and UPS2. At this time, there is a disconnection of the communication cable connecting the parallel communication interface in the first parallel subsystem 201, recorded as a. In the second parallel subsystem 202, there is a disconnection of the communication cable connecting the parallel communication interface of another subsystem, again recorded as b. The specific details of the disconnection events for each parallel subsystem are shown in Table 3 below.

[0048] Table 3

[0049] At this time, the disconnection event of the first parallel subsystem 201 includes the first event; therefore, UPS1 and UPS2 included in the first parallel subsystem 201 need to be switched to bypass operation mode. The disconnection event of the second parallel subsystem 202 includes the third event; therefore, UPS3 and UPS4 included in it continue to maintain inverter operation mode.

[0050] Condition 3: Line 1 disconnection occurs. Both UPS1 and UPS2 can detect the disconnection, and UPS3 and UPS4 can receive disconnection notifications from UPS1 and UPS2. At this time, the communication cable connected to the parallel communication interface in the first parallel subsystem 201 is disconnected, denoted as 'a'. In the second parallel subsystem 202, the communication cable connected to the parallel communication interface of another subsystem is disconnected, denoted as 'b'. Line 3 disconnection occurs. UPS1 receives disconnection notifications from UPS3 and UPS4, and UPS2 also receives disconnection notifications from UPS3 and UPS4. UPS3 and UPS4 can detect the disconnection of Line 3 themselves. At this time, there is no disconnection of the communication cable connected to the parallel communication interface in the first parallel subsystem 201, denoted as 'b'. In the second parallel subsystem 202, there are disconnections of the communication cables connected to the parallel communication interface, denoted as 'a'. The specific details of the disconnection events for each parallel subsystem are shown in Table 4 below.

[0051] Table 4

[0052] At this time, the disconnection events of the first parallel subsystem 201 and the second parallel subsystem 202 both include the first event. Therefore, UPS1 / 2 / 3 / 4 all need to switch to bypass operation mode.

[0053] Condition 4: Line 1 disconnection occurs. UPS1 and UPS2 can detect the disconnection, and UPS3 and UPS4 can receive disconnection notifications from UPS1 and UPS2. At this time, the communication cable connecting the parallel communication interface in the first parallel subsystem 201 is disconnected, denoted as 'a'. Similarly, the communication cable connecting the parallel communication interface of another subsystem in the second parallel subsystem 202 is disconnected, denoted as 'b'. Line 2 disconnection occurs. UPS2 and UPS3 can detect the disconnection of Line 2, and UPS1 / 4 can receive disconnection notifications from UPS2 and UPS3. UPS4 can also detect the disconnection of Line 4, and UPS2 / 3 can receive disconnection notifications from UPS1 and UPS4. At this time, neither the first parallel subsystem 201 nor the second parallel subsystem 202 has a disconnected communication cable connecting the parallel communication interface, and both parallel subsystems are again denoted as 'b'. Consequently, all power conversion equipment is also denoted as 'b'. The specific details of the disconnection events for each parallel subsystem are shown in Table 5 below.

[0054] Table 5

[0055] At this time, the disconnection event of the first parallel subsystem 201 includes the first event, at which point UPS1 and UPS2 included in it need to switch to bypass operation. The disconnection event of the second parallel subsystem 202 includes the third event, at which point UPS3 and UPS4 included in it continue to maintain inverter operation.

[0056] For the control method described above, see, for example, see... Figure 3 The parallel system shown below is illustrated with several examples.

[0057] Example 1: Suppose that communication cables 304 (communication cables between parallel communication interfaces in the third parallel subsystem), 306, and 309 are disconnected. The specific details of the disconnection events in each parallel subsystem are shown in Table 6 below.

[0058] Table 6

[0059] At this point, the disconnection event of the third parallel subsystem 301 is the first event, which includes both a and b. Therefore, the power conversion devices 3011 to 3013 included in it all need to switch to bypass operation. The disconnection event of the fourth parallel subsystem 302 is also the first event, which includes both a and b. Therefore, the power conversion devices 3021 to 3023 included in it need to switch to bypass operation. The disconnection event of the fifth parallel subsystem 303 is the third event, which only includes b. Therefore, the power conversion devices 3031 to 3033 included in it can continue to maintain inverter operation.

[0060] Example 2: Suppose that communication cables 306 and 307 are disconnected. The specific details of the disconnection events of each parallel subsystem are shown in Table 7 below.

[0061] Table 7

[0062] At this time, the disconnection event of the third parallel subsystem 301 is a third event containing only b; therefore, the power conversion devices 3011 to 3013 included in it can continue to maintain inverter operation. The disconnection event of the fourth parallel subsystem 302 is also a second event containing only a; therefore, the power conversion devices 3021 to 3023 included in it need to switch to bypass operation. The disconnection event of the fifth parallel subsystem 303 is a third event containing only b; therefore, the power conversion devices 3031 to 3033 included in it can continue to maintain inverter operation.

[0063] Example 3: Suppose that communication cables 305, 306, and 307 are disconnected. The specific details of the disconnection events of each parallel subsystem are shown in Table 8 below.

[0064] Table 8

[0065] At this time, the disconnection event of the third parallel subsystem 301 is a third event containing only b; therefore, the power conversion devices 3011 to 3013 included in it can continue to maintain inverter operation. The disconnection event of the fourth parallel subsystem 302 is also a first event containing both a and b; therefore, the power conversion devices 3021 to 3023 included in it need to switch to bypass operation. The disconnection event of the fifth parallel subsystem 303 is a third event containing only b; therefore, the power conversion devices 3031 to 3033 can continue to maintain inverter operation.

[0066] Based on the same inventive concept, this application also provides a control method for a power conversion device, wherein the power conversion device is any one in a parallel system, the parallel system is any of the parallel systems described above, and at least two communication cables in the parallel system are disconnected; the method includes: determining a disconnection event of the power conversion device based on the disconnection status of the current parallel system to which the power conversion device is located; wherein, the current parallel subsystem to which the power conversion device is located is defined as the local subsystem, and other parallel subsystems besides the local subsystem are defined as other subsystems; when a communication cable connected to a parallel communication interface in the local subsystem is disconnected, it is marked as a first flag; when the local subsystem... When a communication cable connected to the BSC interface of the machine subsystem is disconnected, or when a communication cable connected to the parallel communication interface or BSC interface of another machine subsystem is disconnected, it is recorded as the second flag. The disconnection events in which at least two communication cables of the machine subsystem are disconnected are respectively the first event containing the first flag and the second flag, the second event containing only the first flag, and the third event containing only the second flag. The operating state of the current power conversion equipment is controlled according to the disconnection event. When the disconnection event is the third event, the current power conversion equipment operates in the first state. When the disconnection event is the first event or the second event, the current power conversion equipment operates in the second state.

[0067] The difference from the previous embodiment is that the previous embodiment was more applicable to parallel subsystems with a central controller, where the central controller determined whether the parallel subsystem was operating in the first or second state and then sent the result to all power conversion devices within the subsystem. This embodiment, however, is more applicable to parallel subsystems without a central controller, where each power conversion device determines whether it is operating in the first or second state.

[0068] In some embodiments, the power conversion device is an uninterruptible power supply, with a first state being an inverter operation state and a second state being an operation state where the mains power is connected via a bypass.

[0069] It should be noted that the control method here is described from the perspective of each power conversion device. It is essentially the same as the control method described from the perspective of the parallel subsystem. You can refer to the examples described earlier for understanding, and it will not be repeated here.

[0070] In this embodiment of the application, through the above-described interface layout, circuit connection method and operation status control method, interface redundancy and wiring complexity can be reduced. At the same time, an intelligent communication and fault response mechanism is introduced, which enables flexible operation and efficient control under various working conditions, and significantly improves the stability, reliability and maintainability of the parallel system.

[0071] The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, and improvements made within the spirit and scope of this application are included within the scope of protection of this application.

Claims

1. A parallel system, characterized in that, include: At least two parallel subsystems are provided, each including at least one power conversion device, and each power conversion device including two communication interfaces. Two of the communication interfaces within any parallel subsystem are defined as BSC interfaces, and the other communication interfaces are defined as parallel communication interfaces. The power conversion devices within the same parallel subsystem are connected sequentially to each other via communication cables. The BSC interfaces between at least two parallel subsystems are connected sequentially via communication cables. When there is more than one power conversion device in a parallel subsystem, the two BSC interfaces are located on different power conversion devices.

2. The parallel system according to claim 1, characterized in that, Both the parallel communication interface and the BSC interface follow the Controller Area Network (CAN) communication protocol for data transmission.

3. The parallel system according to claim 2, characterized in that, The at least one parallel subsystem includes a first parallel subsystem and a second parallel subsystem. The first parallel subsystem includes a first power conversion device and a second power conversion device. The second parallel subsystem includes a third power conversion device and a fourth power conversion device. The first communication interfaces of the first power conversion device, the second power conversion device, the third power conversion device, and the fourth power conversion device are all configured as parallel communication interfaces. The second communication interfaces of the first power conversion device, the second power conversion device, the third power conversion device, and the fourth power conversion device are all configured as BSC interfaces. The first communication interface of the first power conversion device is connected to the first communication interface of the second power conversion device via a first communication cable; The first communication interface of the third power conversion device is connected to the first communication interface of the fourth power conversion device via a second communication cable. The second communication interface of the first power conversion device is connected to the second communication interface of the fourth power conversion device via a third communication cable; The second communication interface of the second power conversion device is connected to the second communication interface of the third power conversion device via a fourth communication cable.

4. The parallel system according to claim 2 or 3, characterized in that, The power conversion equipment is an uninterruptible power supply.

5. A control method for a parallel subsystem, characterized in that, The parallel subsystem is any one of the parallel subsystems described in any one of claims 1 to 4, and the parallel system has at least two communication cables disconnected; the method includes: The disconnection event of the current parallel subsystem is determined based on the disconnection status of the parallel system. The current parallel subsystem is defined as the local subsystem, and all other parallel subsystems are defined as other subsystems. A first flag is recorded when a communication cable connected to the parallel communication interface in the local subsystem is disconnected. A second flag is recorded when a communication cable connected to the BSC interface in the local subsystem is disconnected, or when a communication cable connected to either the parallel communication interface or the BSC interface in any other subsystem is disconnected. Disconnection events where at least two communication cables in the local subsystem are disconnected are respectively classified as a first event containing both the first and second flags, a second event containing only the first flag, and a third event containing only the second flag. The operating state of the parallel subsystem is controlled according to the disconnection event, wherein when the disconnection event is the third event, the local subsystem operates in the first state; when the disconnection event is the first event or the second event, the local subsystem operates in the second state.

6. The method according to claim 5, characterized in that, The power conversion device is an uninterruptible power supply. The first state is the inverter operation state, and the second state is the operation state in which the mains power is connected via a bypass.

7. The method according to claim 5, characterized in that, The method further includes: When the potential of the parallel communication interface contained in the local subsystem is detected to be at a preset potential, it is determined that the communication cable connected to the parallel communication interface in the local subsystem is disconnected. And / or, When the potential of the BSC interface contained in the local subsystem or the other subsystem is detected to be at the preset potential, it is determined that the communication cable connected to the BSC interface in the local subsystem or the other subsystem is disconnected.

8. The method according to claim 5, characterized in that, The method further includes: obtaining information about the disconnection of the communication cable connected to the parallel communication interface or the BSC interface of the other subsystem via the Controller Area Network (CAN) communication protocol.

9. A control method for a power conversion device, characterized in that, The power conversion device is any one of the parallel systems, the parallel system being the parallel system as described in any one of claims 1 to 4, and the parallel system having at least two communication cables disconnected; the method includes: The disconnection event of the power conversion equipment is determined based on the disconnection status of the parallel system to which the power conversion equipment is located. The parallel subsystem to which the power conversion equipment is located is defined as the local subsystem, and all other parallel subsystems are defined as other subsystems. A first flag is recorded when a communication cable connected to the parallel communication interface in the local subsystem is disconnected. A second flag is recorded when a communication cable connected to the BSC interface in the local subsystem is disconnected, or when a communication cable connected to either the parallel communication interface or the BSC interface in another subsystem is disconnected. Disconnection events where at least two communication cables in the local subsystem are disconnected are respectively classified as a first event containing both the first and second flags, a second event containing only the first flag, and a third event containing only the second flag. The operating state of the power conversion device is controlled according to the disconnection event, wherein when the disconnection event is the third event, the power conversion device is currently operating in the first state, and when the disconnection event is the first event or the second event, the power conversion device is currently operating in the second state.

10. The method according to claim 9, characterized in that, The power conversion device is an uninterruptible power supply. The first state is the inverter operation state, and the second state is the operation state in which the mains power is connected via a bypass.

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