A control device and control method for microgrid parallel operation

Abstract

The present application discloses a control device for parallel operation of a microgrid and a control method thereof, wherein the control device comprises an input module, a port hybrid network, an output module and a control module. The microgrid is connected to the mains power grid through the input module, the port hybrid network and the output module, and then the control module controls the smooth switching of the port hybrid network during the grid connection process and the grid disconnection process, which can meet the fast grid connection requirements between the microgrid and the mains power grid; in addition, since a rich number of relay control circuits are set in the port hybrid network, it is convenient for the control module to establish a power path according to the configured parallel operation mode, and achieve the control purpose of various parallel operation situations, so that the AC power received by the input module can be transmitted to the mains power grid through the output module in the corresponding parallel operation mode.

Description

Technical Field

[0001] The present application relates to the technical field of microgrid parallel control, and in particular to a microgrid parallel control device and a control method thereof. Background Art

[0002] To support the development of clean energy, the power industry has vigorously developed various renewable energy sources on the power generation side, which has led to the rapid development of distributed power sources such as wind power generation and photovoltaic power generation and microgrids. Microgrids are a powerful supplement to large power grids and an important part of the smart grid field. Microgrids can make full use of the complementarity of multiple distributed energy sources and improve the utilization efficiency of multiple energy sources.

[0003] With the massive access of distributed power sources, the traditional distribution network has been transformed into an active distribution network. Distributed power sources constitute microgrids. When microgrids are reintegrated into the large power grid, synchronization judgment is required to prevent damage to power equipment caused by asynchronous closing. This requires a solution for fast grid connection of microgrids, which enables faster and more accurate synchronization control of microgrids, ensures the minimum impact on the mains power grid, and guarantees the reliability of power supply within the microgrid.

[0004] For example, a method for rapid grid-connection of a microgrid based on three-phase independent regulation is disclosed in the patent document (CN104065104B), which emphasizes the use of three-phase voltage parameters on the distribution network side and the microgrid side to determine and control the synchronization of the circuit breaker to achieve grid connection. It can be understood that this scheme is a solution for three-phase grid connection, but may not be applicable to other grid-connection situations, and it is impossible to further understand the solutions for more grid-connection situations.

[0005] There are various application requirements in microgrid grid-connected technology under various grid-connected scenarios. The existing solutions cannot meet the requirements of multi-mode fast and friendly grid-connection between microgrids and external large power grids, and there are certain shortcomings. Summary of the invention

[0006] The technical problem solved by the present application is: how to quickly and accurately connect to the grid in various grid connection situations. To solve the technical problem, the present application provides a control device and a control method for microgrid parallel connection.

[0007] In a first aspect, an embodiment of the present application discloses a control device for parallel operation of a microgrid, comprising: an input module, the input module having a plurality of first port groups, each of the first port groups being used to electrically connect to an inverter component; the inverter component being configured to invert direct current generated by the microgrid into alternating current; an output module, the output module having a second port group, the second port group being used to electrically connect to a mains power grid; a port hybrid network being provided between the plurality of first port groups and the second port groups, the port hybrid network having connecting lines with different ports and relays connected in series to each connecting line; a control module, the control module being signal-connected to the port hybrid network, and being used to enable each relay in the port hybrid network according to a preset parallel operation mode, so that a power path conforming to the parallel operation mode is formed between the plurality of first port groups and the second port groups, and the power path can transmit the alternating current received by the input module into the mains power grid through the output module.

[0008] Furthermore, each of the first port groups includes a phase line port and a neutral line port, and the second port group includes three phase line ports and one neutral line port; the port hybrid network is configured as follows: the phase line ports in each of the first port groups are connected to the three phase line ports in the second port group through multiple connecting lines, the neutral line port in at least one of the first port groups is connected to the neutral line port in the second port group through a connecting line, connecting lines are provided between the neutral line ports in multiple of the first port groups, connecting lines are provided between the phase line ports in multiple of the first port groups, and connecting lines are provided between the neutral line port in at least one of the first port groups and the phase line ports in other of the first port groups.

[0009] Further, the parallel operation mode includes any one of three-phase parallel operation, single-phase parallel operation, and split-phase parallel operation; in the three-phase parallel operation mode, the control module controls the formation of one-to-one corresponding passages between the phase line ports in each of the first port groups and the three phase line ports in the second port group, and controls the formation of interconnected power passages between the neutral line ports in each of the first port groups and the neutral line ports in the second port group; in the single-phase parallel operation mode, the control module controls the formation of interconnected power passages between the phase line ports in each of the first port groups and one of the phase line ports in the second port group, and controls the formation of interconnected power passages between the neutral line ports in each of the first port groups and the neutral line ports in the second port group; in the split-phase parallel operation mode, the control module controls the formation of interconnected power passages between at least one of the phase line ports in the first port group and one of the phase line ports in the second port group, as well as between the neutral line ports in other of the first port groups, and controls the formation of interconnected power passages between at least one of the neutral line ports in the first port group and one of the neutral line ports in the second port group, as well as between the phase line ports in other of the first port groups.

[0010] Each of the plurality of first port groups is provided with a first acquisition component, which is used to acquire power information of the alternating current generated by the correspondingly connected inverter component and send it to the control module; the second port group is provided with a second acquisition component, which is used to acquire grid information of the correspondingly connected mains power grid and send it to the control module; the control module is used to determine whether it is suitable for parallel connection based on the power information of the alternating current generated by the inverter component and the grid information of the mains power grid, and enable each relay in the port hybrid network according to a preset parallel connection mode when it is suitable for parallel connection; wherein, the control module determines that the conditions for being suitable for parallel connection include that the mains power grid has a certain grid type, and that the power information of the alternating current generated by the inverter component can adapt to the grid type.

[0011] Furthermore, the control module is signal-connected with the inverter components that are electrically connected to the multiple first port groups respectively, and the control module is used to set operating parameters of the inverter components so that the power information of the alternating current generated by the inverter components can match the grid information of the municipal power grid.

[0012] Furthermore, the control module includes a central component and a drive component; the central component is used to generate an enable signal for each relay in the port hybrid network according to a preset parallel mode; the drive component is connected to the signal of each relay in the port hybrid network, and is used to drive the corresponding relay to operate based on the enable signal generated by the central component; the central component is also used to obtain the status information of each relay in the port hybrid network through the drive component.

[0013] In a second aspect, a control method is disclosed in one embodiment of the present application, which acts on a control device for parallel connection of a microgrid disclosed in the first aspect, and the control method includes: obtaining the grid type of the mains grid and the power information of the alternating current generated by the inverter component connected to the microgrid to be paralleled; determining the corresponding parallel connection mode when it is determined that the power information is compatible with the grid type; and enabling each relay in the port hybrid network included in the control device according to the parallel connection mode, so that a power path that conforms to the parallel connection mode is formed between the multiple first port groups and the second port groups.

[0014] Furthermore, after obtaining the grid type of the mains power grid and the power information of the inverter component connected to the microgrid to be connected to generate AC power, it also includes: storing the grid type so as to directly read the grid type after the control device is powered off and restarted; and judging whether the inverter component is in a standby state based on the power information, and if not, controlling the inverter component to enter a standby state.

[0015] Furthermore, before obtaining the grid type of the municipal power grid, it also includes: controlling the control device to enter the bypass mode; after enabling each relay in the port hybrid network included in the control device according to the parallel mode, it also includes: obtaining the status information of each relay in the port hybrid network, and controlling the control device to exit the bypass mode after confirming that each relay has completed the corresponding action based on the status information, and controlling the inverter component to exit the standby state.

[0016] Furthermore, the determining of the corresponding parallel mode when judging whether the power information is compatible with the grid type includes: obtaining the number and AC parameters of the inverter components to which the plurality of first port groups are electrically connected according to the power information; judging whether the number and AC parameters of the inverter components satisfy the grid type, the grid type including any one of three-phase, single-phase, and split-phase; and determining the corresponding parallel mode from three-phase parallel, single-phase parallel, and split-phase parallel under the condition that the grid type is satisfied.

[0017] The beneficial effects of this application are:

[0018] According to the above-mentioned embodiment, a control device and a control method for parallel operation of a microgrid are provided. The control device includes an input module, a port hybrid network, an output module and a control module. The input module has a plurality of first port groups and each first port group is used to electrically connect to an inverter component. The output module has a second port group and the second port group is used to electrically connect to a mains power grid. A port hybrid network is provided between the plurality of first port groups and the second port groups, and the port hybrid network has connecting lines with different ports and relays connected in series to each connecting line. The control module is used to enable each relay in the port hybrid network according to a preset parallel operation mode, so that a power path that conforms to the parallel operation mode is formed between the plurality of first port groups and the second port groups. It can be understood that the microgrid is connected to the mains power grid through the input module, the port hybrid network, and the output module, and then the control module is used to smoothly switch the port hybrid network between the grid-connected process and the grid-off process, which can meet the rapid grid-connected demand between the microgrid and the mains power grid; in addition, since a variety of relay control circuits are set up in the port hybrid network, it is convenient for the control module to establish a power path according to the configured parallel mode, and achieve the control purpose of various parallel situations, so that the AC power received by the input module can be transmitted to the mains power grid through the output module in the corresponding parallel mode.

[0019] The control method provided in the present application mainly acts on the control device of the microgrid parallel operation, and can adaptively determine the parallel operation mode according to the grid type and the power information of the AC power, thereby establishing a power path between the input module and the output module that meets the requirements of the parallel operation mode, and can meet the application requirements of various parallel operation scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a structural diagram of a control device for parallel connection of a microgrid in one embodiment of the present application;

[0021] Figure 2 This is a principle block diagram of a control device for parallel connection of microgrids in one embodiment of the present application;

[0022] Figure 3 This is an equivalent schematic diagram of a three-phase parallel machine in one embodiment of the present application;

[0023] Figure 4 This is an equivalent schematic diagram of a single-phase parallel machine in an embodiment of the present application;

[0024] Figure 5 This is an equivalent schematic diagram of a split-phase parallel machine in one embodiment of the present application;

[0025] Figure 6 A circuit diagram of a relay driving circuit in one embodiment of the present application;

[0026] Figure 7 This is a flow chart of a control method in one embodiment of the present application;

[0027] Figure 8 It is a detailed flow chart of a control method in one embodiment of the present application. DETAILED DESCRIPTION

[0028] In the description of the present invention, it should be understood that the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0029] The technical solution of the present application is further described in detail below through some embodiments and in conjunction with the accompanying drawings.

[0030] Please refer to Figure 1 The present application discloses a control device for parallel connection of a microgrid, which mainly includes an input module 101, an output module 103, a port hybrid network 102 and a control module 104, which are described below respectively.

[0031] The input module 101 has a plurality of first port groups, each of which is used to electrically connect to an inverter component; the inverter component here is configured to invert the direct current generated by the microgrid into alternating current. Figure 1 The case of three first port groups is provided, for example, the first port group L1-L2 is electrically connected to the inverter component 1, the first port group L3-L4 is electrically connected to the inverter component 2, and the first port group L5-L6 is electrically connected to the inverter component 3, and the inverter component 1, the inverter component 2, and the inverter component 3 can be electrically connected to energy storage batteries, photovoltaic panels, backup generators and other equipment. Of course, the number of first port groups can also be expanded or reduced as needed.

[0032] The output module 103 has a second port group, which is used to electrically connect to the mains power grid. Figure 1 A second port group is provided, for example, including ports R, N, S, and T, which can be connected to the mains power grid in the form of three-phase four-wires.

[0033] A port hybrid network 102 is provided between the plurality of first port groups in the input module 101 and the second port group in the output module 103. The port hybrid network 102 has connection lines with different ports and a relay connected in series to each connection line. Figure 1 In the embodiment, the port hybrid network 102 provides a variety of connection forms between different ports, which can realize direct connection between two ports or interconnection between three or more ports. For example, connecting lines can be established between ports L1, L2, L3, L4, L5, L6 and ports R, N, S, T, and corresponding relays can be set on each connecting line, so that the on and off of the connecting line can be controlled.

[0034] The control module 104 is connected to the port hybrid network 102 by signal. The control module 104 is used to enable each relay in the port hybrid network 102 according to a preset parallel mode, so that a power path that conforms to the parallel mode is formed between the multiple first port groups and the second port groups. The formed power path can transmit the AC power received by the input module 101 into the mains power grid through the output module 103.

[0035] See also Figure 2 In this embodiment, the power connection between the inverter assembly and the mains grid is essentially achieved through the control device, so that the microgrid connected to the inverter assembly is connected to the mains grid, and the parameter requirements and mode requirements of the grid connection must be met. Of course, a memory and the control device can also be set to connect signals, and the memory can be used to store some default parameters and process parameters generated by the control device, such as parameters for storing grid types.

[0036] In a specific embodiment, each first port group includes a phase line port and a neutral line port, and the second port group includes three phase line ports and a neutral line port, then the port hybrid network 102 is configured as follows: the phase line ports in each first port group are connected to the three phase line ports in the second port group through a plurality of connecting lines, the neutral line port in at least one first port group is connected to the neutral line port in the second port group through a connecting line, a connecting line is provided between the neutral line ports in a plurality of first port groups, a connecting line is provided between the phase line ports in a plurality of first port groups, and a connecting line is provided between the neutral line port in at least one first port group and the phase line ports in other first port groups. It can be understood that this cross-connection method between different phase line ports and neutral line ports can realize a variety of port interconnection requirements, and is conducive to flexible configuration of power paths to meet different parallel modes.

[0037] for example Figure 1 , the first port group L1-L2 includes a phase port L1 and a neutral port L2, the first port group L3-L4 includes a phase port L3 and a neutral port L4, the first port group L5-L6 includes a phase port L5 and a neutral port L6, and the second port group includes three phase ports R, S, T and a neutral port N. Then, the phase ports L1, L3, and L5 in the multiple first port groups can be connected to the three phase ports R, S, and T in the second port group through multiple connecting lines, the neutral port L2 in the first port group is connected to the neutral port N in the second port group through a connecting line, a connecting line is provided between the neutral ports L2, L4, and L6 in the multiple first port groups, a connecting line is provided between the phase ports L1, L3, and L5 in the multiple first port groups, and a connecting line is provided between the neutral port L2 in the first port group and the phase ports L3 and L5 in other first port groups.

[0038] It should be noted that R, S, and T in the mains power represent the three phase lines of the three-phase power supply, which correspond to the A, B, and C phases in the three-phase power supply. In the three-phase power system, these three phase lines carry different AC voltages and jointly provide power to the load. N in the mains power represents the neutral line in the three-phase power supply, which is used to connect the metal casing of the equipment or grounding to ensure electrical safety. R, N, S, and T in the mains power grid can be correctly connected according to the working conditions to ensure the stable operation of the power system and the safe use of the users. In particular, when connecting to the mains power grid, the correct phase sequence and grounding requirements should be followed to ensure the safety and efficiency of the power system.

[0039] In a specific embodiment, the parallel mode adopted by the control module 104 includes any one of three-phase parallel mode, single-phase parallel mode, and split-phase parallel mode.

[0040] In the three-phase parallel mode, the control module 104 controls the phase line ports in each first port group and the three phase line ports in the second port group to form a one-to-one corresponding path, and controls the neutral line ports in each first port group and the neutral line ports in the second port group to form an interconnected power path. Figure 1 When the three phases are paralleled, the phase line ports L1, L3, and L5 in the first port group respectively form a one-to-one corresponding path with the three phase line ports R, S, and T in the second port group, and an interconnected power path is formed between the neutral line ports L2, L4, and L6 in each first port group and the neutral line port N in the second port group.

[0041] In the single-phase parallel mode, the control module 104 controls the phase line ports in each first port group and one phase line port in the second port group to form an interconnected power path, and controls the neutral line ports in each first port group and the neutral line ports in the second port group to form an interconnected power path. Figure 1 When single-phase parallel operation is used, an interconnected power path is formed between the phase line ports L1, L3, L5 in each first port group and a phase line port R in the second port group, and an interconnected power path is formed between the neutral line ports L2, L4, L6 in each first port group and the neutral line port N in the second port group.

[0042] In the split-phase parallel mode, the control module 104 controls the formation of an interconnected power path between the phase line port in at least one first port group and one phase line port in the second port group, and between the phase line ports in other first port groups, and controls the formation of an interconnected power path between the neutral line port in at least one first port group and one neutral line port in the second port group, and between the phase line ports in other first port groups. Figure 1When the phases are split and connected in parallel, an interconnected power path is formed between the phase line port L1 in the first port group and one phase line port R in the second port group, and between the phase line port L4 in other first port groups; and an interconnected power path is formed between the neutral line port L2 in the first port group and one neutral line port N in the second port group, and between the phase line port L5 in other first port groups; of course, a power path can also be formed between the phase line port L3 in the first port group and the neutral line port L6 in other first port groups.

[0043] See also Figure 1 For the port hybrid network 102, a relay RY1 is set on the connection line between the port L1 and the port L3, a relay RY2 is set on the connection line between the port L3 and the port L5, a relay RY3 is set on the connection line between the port L2 and the port L4, a relay RY4 is set on the connection line between the port L4 and the port L6, a relay RY5 is set on the connection line between the port L1 and the port L4, a relay RY6 is set on the connection line between the port L3 and the port L6, a relay RY6 is set on the connection line between the port L3 and the port L6, a relay RY7 is set on the connection line between the port L2 and the port L5, a relay RY8 is set on the connection line between the port L1 and the port R, a relay RY9 is set on the connection line between the port L2 and the port N, a relay RY10 is set on the connection line between the port L3 and the port S, and a relay RY11 is set on the connection line between the port L5 and the port T.

[0044] For the three-phase parallel mode, the control module 104 can send an open enable signal (hereinafter referred to as "K signal") to relays RY3 and RY4, so that relays RY3 and RY4 are closed to form a path; it is also necessary to send a disconnect enable signal (hereinafter referred to as "D signal") to other relays to disconnect other relays, so that the three-phase parallel operation inside the port hybrid network 102 is completed. After a delay, the control module 104 sends a K signal to relays RY8, RY9, RY10, and RY11 to close these four relays to connect the mains power grid, thereby forming a Figure 3 It can be understood that at this time, the AC power generated by the inverter components 1, 2, and 3 can be transmitted to the mains power grid in a three-phase parallel manner.

[0045] For the single-phase parallel mode, the control module 104 can send a K signal to relays RY1, RY2, RY3, and RY4 to close the relays RY1, RY2, RY3, and RY4, and send a D signal to other relays to disconnect the other relays; the single-phase parallel operation inside the port hybrid network 102 has been completed. After a delay, the control module 104 sends a K signal to RY8 and RY9 to close the relays RY8 and RY9 to connect to the mains power grid, thereby forming Figure 4 It can be understood that at this time, the AC power generated by the inverter components 1, 2, and 3 can be transmitted to the mains power grid in a single-phase parallel manner.

[0046] For the split-phase parallel mode, the control module 104 can send a K signal to relays RY5, RY6, and RY7 to close the relays RY5, RY6, and RY7, and send a D signal to other relays to disconnect the other relays. The internal split-phase parallel of the port hybrid network 102 has been completed. After a delay, the control module 104 sends a K signal to RY8 and RY9 to close the relays RY8 and RY9 to connect to the mains power grid, thereby forming Figure 5 It can be understood that at this time, the AC power generated by the inverter components 1, 2, and 3 can be transmitted to the mains power grid by means of split-phase parallel operation.

[0047] It should be noted that Figure 1 Three inverter components and corresponding three first port groups are used to illustrate the implementation principle of multi-mode grid-connected microgrid. This is only a common situation. Users can freely choose the number of inverter components and the number of first port groups according to their needs. For example, when two inverter components and the corresponding two first port groups are enabled, the single-phase parallel mode can be executed, and when more than three inverter components and the corresponding three or more first port groups are enabled, any of the three-phase parallel, single-phase parallel, and split-phase parallel modes can be executed. Of course, as the number of ports in the port hybrid network 102 increases, more types of parallel modes can be realized, which will not be explained one by one here.

[0048] In a specific embodiment, each of the plurality of first port groups is provided with a first acquisition component ( Figure 1 The first acquisition component is used to collect the power information of the AC power generated by the corresponding connected inverter component and send it to the control module 104. In addition, the second port group is provided with a second acquisition component ( Figure 1(not shown in the figure), the second acquisition component is used to collect the grid information of the corresponding connected mains power grid and send it to the control module 104. Then, the control module 104 is used to determine whether it is suitable for parallel operation according to the power information of the alternating current generated by the inverter component and the grid information of the mains power grid, and when it is suitable for parallel operation, enable each relay in the port hybrid network according to the preset parallel operation mode; wherein, the control module determines that the conditions suitable for parallel operation include that the mains power grid has a certain grid type, and the power information of the alternating current generated by the inverter component can adapt to the grid type.

[0049] It should be noted that the first acquisition component and the second acquisition component can be common signal acquisition components such as ammeters, voltmeters, power meters, frequency meters, phase meters, etc., and preferably can collect power information of voltage, frequency, and phase. The control module 104 can determine whether the grid type of the mains power grid belongs to three-phase, single-phase, or split-phase based on the grid information of the mains power grid (such as voltage, frequency, and phase), and determine whether the power information (voltage, frequency, and phase) of the alternating current generated by the inverter component meets the parameter requirements of three-phase, single-phase, or split-phase.

[0050] In a specific embodiment, the control module 104 can also be connected to the inverter components 1, 2, and 3 that are electrically connected to the plurality of first port groups respectively to perform signal connection. Then, the control module 104 is used to set the operating parameters of the inverter components 1, 2, and 3 so that the power information of the alternating current generated by the inverter components 1, 2, and 3 can match the grid information of the mains power grid. For example, the mains power grid has a voltage of 380V, a frequency of 50KZ, and a phase , then the inverter components 1, 2, and 3 can be controlled to generate 380V, 50KZ, of alternating current.

[0051] In one specific embodiment, the control module 104 includes a central component and a drive component ( Figure 1 The central component is equivalent to a logic processing circuit such as a CPU, an MCU, a single-chip microcomputer, or an FPGA, and is used to generate an enable signal for each relay in the port hybrid network 102 according to a preset parallel mode; the drive component is connected to each relay signal in the port hybrid network, and is used to drive the corresponding relay to operate based on the enable signal generated by the central component; of course, the central component is also used to obtain the status information of each relay in the port hybrid network through the drive component, such as obtaining the status information of whether the relay is on or off.

[0052] The drive assembly includes the drive circuit for a single relay and can be found in Figure 6, the magnetic latching type relay is kept closed or disconnected by the action of the internal permanent magnet, and is completed by a certain trigger pulse, so four transistors S1, S2, S3, and S4 can be set at both ends of the relay RY to realize the on-off drive of the relay RY. The PIN1 and PIN2 of the circuit are used to connect the connection line in the port hybrid network 102 in series, and the gates of the transistors S1, S2, S3, and S4 are used to connect the control pins of the central component. The transistors S1, S4, S2, and S3 are complementary to each other to realize the reversal of the current to realize the on-off of the magnetic latching relay. Assuming that only the transistors S1 and S4 are turned on to close the relay RY, it is considered that the central component has generated a K signal. Assuming that only the transistors S2 and S3 are turned on to disconnect the relay RY, it is considered that the central component has generated a D signal.

[0053] Please refer to Figure 7 The present application discloses a control method, which acts on the control device for parallel connection of a microgrid disclosed in the above embodiment. The control method mentioned includes steps 201 to 203, which are described below respectively.

[0054] Step 201, obtain the grid type of the mains grid and the power information of the AC power generated by the inverter assembly connected to the microgrid to be connected in parallel. For example, the grid information of the mains grid connected to the second port group is obtained from the second acquisition component, and the grid type of the mains grid is obtained based on the grid information analysis; the power information of the AC power generated by the inverter assembly connected to the first port group is obtained from the first acquisition component.

[0055] Step 202: When it is determined that the power information and the grid type are compatible, a corresponding parallel mode is determined.

[0056] Step 203 : enabling each relay in the port hybrid network included in the control device according to the parallel mode, so that a power path that complies with the parallel mode is formed between the plurality of first port groups and the second port groups.

[0057] It can be understood that the above steps 201, 202, and 203 can be performed by Figure 1 The control module 104 in is executed.

[0058] In a specific embodiment, after obtaining the grid type of the mains grid and the power information of the AC power generated by the inverter assembly connected to the microgrid to be paralleled, that is, after step 201, it also includes:

[0059] (1) Storing the grid type so that the grid type can be directly read after the control device is powered off and restarted. For example, the grid type or even the grid information of the mains grid can be stored in Figure 2 memory shown for easy retrieval.

[0060] (2) Determine whether the inverter component is in standby state based on the power information. If not, control the inverter component to enter the standby state. The power information can be used to determine whether the inverter component has power output. If it has output, the inverter component is considered to be in a normal state. If it has no output, the inverter component is considered to be in a standby state.

[0061] In a specific embodiment, before obtaining the grid type of the mains grid, that is, before step 201, it also includes: controlling the entire control device to enter the bypass mode (that is, BYPASS mode, allowing the device to switch to the backup circuit under specific conditions to maintain the normal operation of the device). After enabling each relay in the port hybrid network included in the control device according to the parallel mode, that is, after step 203, it also includes: obtaining the status information of each relay in the port hybrid network 102, and controlling the entire control device to exit the bypass mode after confirming that each relay has completed the corresponding action based on the status information, and controlling the inverter component to exit the standby state, that is, enter the normal state.

[0062] In a specific embodiment, determining the corresponding parallel mode when judging whether the power information and the grid type are compatible includes:

[0063] (1) Obtaining the number of inverter components electrically connected to the plurality of first port groups and AC parameters according to the power information. It can be understood that the power information includes information such as whether the inverter component has power output and the voltage, frequency, phase, etc. of the output AC power, which can be used to analyze and obtain the number of inverter components connected to the input module and the AC parameters.

[0064] (2) Determine whether the number of inverter components and AC power parameters meet the grid type, which includes any one of three-phase, single-phase, and split-phase. For example, when two inverter components are enabled, the single-phase parallel mode can be executed, and when more than three inverter components are enabled, any one of three-phase parallel, single-phase parallel, and split-phase parallel modes can be executed; of course, as the number of ports in the port hybrid network 102 increases, more types of parallel modes can be realized. For example, the AC power parameters (voltage, frequency, phase) are considered to meet the grid type only when they meet the mains standard.

[0065] (3) Under the condition of satisfying the grid type, determine the corresponding parallel mode from three-phase parallel, single-phase parallel, and split-phase parallel.

[0066] In a specific embodiment, see Figure 8 , a specific flow chart of microgrid parallel control is given. The process can be Figure 1The control module 104 in the program is specifically executed. After the program starts running, the control module 104 guides the control device to enter the bypass mode, and can also send a D signal to all relays in the port hybrid network 102, so that all relays are disconnected. The control module 104 obtains the grid information (such as voltage, frequency, and phase) of the mains power grid through the second acquisition component, obtains the grid type (such as three-phase, single-phase, and split-phase) of the mains power grid based on the grid information, and stores the grid type through the memory (such as the grid type is stored in Flash) to prevent the need for resetting after power failure. The control module 104 obtains the power information (such as voltage, frequency, and phase) of each inverter component through the first acquisition component, and determines whether the inverter component is in a standby state based on the power information. If not, the inverter component is controlled to enter the standby state. If so, the parallel mode (such as three-phase parallel, single-phase parallel, and split-phase parallel mode) is obtained based on the grid type. If so, the corresponding enable signal is sent to each relay based on the parallel mode, such as controlling a part of the relays to be turned on and controlling another part of the relays to be disconnected. Then, the status information of each relay is obtained, and based on the status information, it is determined whether each relay has completed the corresponding action. If not, each relay continues to be enabled. If so, the control device is guided to exit the bypass mode, and the inverter component is controlled to exit the standby state. In this way, the power path between the microgrid and the mains power grid is realized, allowing the AC power generated by the microgrid after inversion to be transmitted to the mains power grid, realizing the parallel connection of the microgrid.

[0067] The above contents are further detailed descriptions of the present application in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the inventive concept of the present application.

Claims

1. A control device for parallel connection of microgrids, characterized in that: include: An input module, wherein the input module has a plurality of first port groups, each of which is used for electrically connecting to an inverter component; The inverter component is configured to invert the direct current generated by the microgrid into alternating current; An output module, the output module having a second port group, the second port group being used for electrically connecting to a mains power grid; A port hybrid network is provided between the plurality of the first port groups and the second port groups, the port hybrid network having connection lines with different ports and a relay connected in series to each connection line; a control module, the control module being connected to the port hybrid network signal and configured to enable each relay in the port hybrid network according to a preset parallel mode, so that a power path conforming to the parallel mode is formed between the plurality of first port groups and the second port groups, and the power path is capable of transmitting the alternating current received by the input module into the mains power grid through the output module; Wherein, each of the first port groups includes a phase line port and a neutral line port, and the second port group includes three phase line ports and one neutral line port; the port hybrid network is configured as follows: the phase line ports in each of the first port groups are connected to the three phase line ports in the second port group through a plurality of connecting lines, the neutral line port in at least one of the first port groups is connected to the neutral line port in the second port group through a connecting line, a connecting line is provided between the neutral line ports in the plurality of the first port groups, a connecting line is provided between the phase line ports in the plurality of the first port groups, and a connecting line is provided between the neutral line port in at least one of the first port groups and the phase line ports in other first port groups; The parallel mode includes any one of three-phase parallel, single-phase parallel and split-phase parallel; In the three-phase parallel mode, the control module controls the phase line ports in each of the first port groups to form a one-to-one corresponding path with the three phase line ports in the second port group, and controls the neutral line ports in each of the first port groups to form an interconnected power path with the neutral line ports in the second port group; In the single-phase parallel mode, the control module controls the phase line ports in each of the first port groups and one of the phase line ports in the second port group to form an interconnected power path, and controls the neutral line ports in each of the first port groups and the neutral line ports in the second port group to form an interconnected power path; In the split-phase parallel mode, the control module controls the formation of an interconnected power path between a phase line port in the first port group and a phase line port in the second port group, and a neutral line port in another first port group, and also controls the formation of an interconnected power path between a neutral line port in the first port group and a neutral line port in the second port group, and a phase line port in another first port group, and further, an interconnected power path is formed between another phase line port in the first port group and a neutral line port in another port group.

2. The control device according to claim 1, characterized in that Each of the plurality of first port groups is provided with a first acquisition component, and the first acquisition component is used to collect power information of the alternating current generated by the correspondingly connected inverter component and send it to the control module; The second port group is provided with a second acquisition component, and the second acquisition component is used to collect grid information of the correspondingly connected mains grid and send it to the control module; The control module is used to determine whether it is suitable for parallel connection according to the power information of the alternating current generated by the inverter assembly and the grid information of the mains power grid, and when it is suitable for parallel connection, enable each relay in the port hybrid network according to a preset parallel connection mode; The control module determines that the conditions suitable for parallel connection include that the mains power grid has a certain grid type, and the power information of the alternating current generated by the inverter component can adapt to the grid type.

3. The control device according to claim 2, characterized in that The control module is signal-connected to the inverter components that are electrically connected to the plurality of first port groups, and is used to set operating parameters for the inverter components so that the power information of the alternating current generated by the inverter components can match the grid information of the municipal power grid.

4. The control device according to claim 1, characterized in that: The control module includes a central component and a drive component; The central component is used to generate an enable signal for each relay in the port hybrid network according to a preset parallel mode; The driving component is connected to each relay signal in the port hybrid network, and is used to drive the corresponding relay to operate based on the enable signal generated by the central component; The central component is also used to obtain status information of each relay in the port hybrid network through the driving component.

5. A control method, characterized in that: A control device for parallel operation of a microgrid according to any one of claims 1 to 4, wherein the control method comprises: Obtain the grid type of the mains grid and the power information of the AC power generated by the inverter components connected to the microgrid to be connected; Determining a corresponding parallel mode when it is determined that the power information is compatible with the grid type; Each relay in the port hybrid network included in the control device is enabled according to the parallel mode, so that a power path that conforms to the parallel mode is formed between the plurality of first port groups and the second port group.

6. The control method according to claim 5, characterized in that: After obtaining the grid type of the mains grid and the power information of the AC power generated by the inverter components connected to the microgrid to be connected, it also includes: storing the power grid type so as to directly read the power grid type after the control device is powered off and restarted; and, According to the power information of the alternating current generated by the inverter assembly connected to the microgrid to be connected in parallel, it is determined whether the inverter assembly is in a standby state. If not, the inverter assembly is controlled to enter the standby state.

7. The control method according to claim 6, characterized in that: Before obtaining the grid type of the mains grid, the method further includes: controlling the control device to enter a bypass mode; After enabling each relay in the port hybrid network included in the control device according to the parallel mode, it also includes: obtaining status information of each relay in the port hybrid network, and controlling the control device to exit the bypass mode after confirming that each relay has completed the corresponding action based on the status information, and controlling the inverter component to exit the standby state.

8. The control method according to claim 5, characterized in that: The determining of the corresponding parallel mode when judging whether the power information is compatible with the grid type includes: Obtaining, according to the power information, the number and AC power parameters of the inverter components electrically connected to the plurality of first port groups respectively; Determining whether the number of the inverter components and the AC power parameters meet the grid type, the grid type including any one of three-phase, single-phase and split-phase; Under the condition that the power grid type is met, a corresponding parallel mode is determined from three-phase parallel operation, single-phase parallel operation and split-phase parallel operation.

Images