Control method and device of flexible interconnection device, storage medium and electronic equipment

Abstract

The invention discloses a control method and device of a flexible interconnection device, a storage medium and electronic equipment, and relates to the technical field of power distribution networks. The method comprises the steps that when it is detected that an alternating current power grid breaks down, a flexible interconnection device used for controlling the alternating current power grid is switched to operate in a current limiting mode, and the flexible interconnection device is controlled to operate in the current limiting mode for a first preset duration; controlling the first alternating current port of the flexible interconnection device to enter a temporary locking state according to the voltage value of the first alternating current port of the flexible interconnection device within the first preset duration; and controlling the operation of the flexible interconnection device according to the residual voltage of the first alternating current port of the flexible interconnection device within the second preset duration. Through application of the method and the device, the problem that the reliability of the flexible interconnection device is relatively low due to the fact that normal work of the flexible interconnection device for controlling the alternating current power grid is difficult to guarantee when the alternating current power grid breaks down in the related technology is solved.

Description

Technical Field

[0001] The present application relates to the technical field of power distribution networks, and in particular to a control method and device for a flexible interconnection device, a storage medium, and an electronic device. Background Art

[0002] With the integration of a high proportion of renewable energy in the power system, and the large-scale access of new loads such as electric vehicles, data centers, and DC buildings, traditional AC distribution systems are facing problems in power quality, power supply reliability, and energy control flexibility. Active distribution network technology based on AC / DC hybrid distribution has received widespread attention. Multi-port flexible interconnection devices have the function of connecting feeders of different voltage levels and different voltage forms and realizing flexible power control, and are a hot topic in the research of AC / DC hybrid distribution systems.

[0003] However, a new type of AC / DC multi-port flexible interconnection device in the related art adopts a mixed frequency modulation strategy to achieve flexible control of multiple AC and DC feeder systems in a flexible distribution network, meeting the compact and economic requirements of the distribution network, but does not consider fault handling. That is, in the related art, when a fault occurs in the AC power grid, it is difficult to ensure that the flexible interconnection device used to control the AC power grid works normally, resulting in low reliability of the flexible interconnection device.

[0004] With regard to the problem in the related art that when an AC power grid fails, it is difficult to ensure that a flexible interconnection device for controlling the AC power grid operates normally, resulting in low reliability of the flexible interconnection device, no effective solution has been proposed so far. Summary of the invention

[0005] The main purpose of the present application is to provide a control method and device for a flexible interconnection device, a storage medium and an electronic device, so as to solve the problem in the related art that when an AC power grid fails, it is difficult to ensure the normal operation of the flexible interconnection device used to control the AC power grid, resulting in low reliability of the flexible interconnection device.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a control method of a flexible interconnection device is provided. The method comprises: when a fault of an AC power grid is detected, the flexible interconnection device used to control the AC power grid is switched to a current limiting mode, and the flexible interconnection device is controlled to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than a preset current value; according to the voltage value of the first AC port of the flexible interconnection device within the first preset time, the first AC port of the flexible interconnection device is controlled to enter a temporary blocking state, and the first AC port of the flexible interconnection device is controlled to be in a temporary blocking state within a second preset time, wherein the first AC port is the AC port corresponding to the AC power grid; the residual voltage of the first AC port of the flexible interconnection device is detected within the second preset time, and the operation of the flexible interconnection device is controlled according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time.

[0007] Further, according to the voltage value of the first AC port of the flexible interconnection device within the first preset time length, controlling the first AC port of the flexible interconnection device to enter a temporarily locked state includes: determining whether the voltage value of the first AC port of the flexible interconnection device is equal to a preset voltage value within the first preset time length; if the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within the first preset time length, switching the flexible interconnection device to a power mode operation, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; if the voltage value of the first AC port of the flexible interconnection device is not equal to the preset voltage value within the first preset time length, controlling the first AC port of the flexible interconnection device to enter a temporarily locked state.

[0008] Further, according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time, controlling the operation of the flexible interconnection device includes: determining whether there is a residual voltage at the first AC port of the flexible interconnection device within the second preset time; if there is a residual voltage at the first AC port of the flexible interconnection device within the second preset time, controlling the first AC port of the flexible interconnection device to enter a permanent locked state, and controlling the second AC port of the flexible interconnection device to be in an operating state, wherein the second AC port is an AC port other than the first AC port in the flexible interconnection device; if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time, switching the flexible interconnection device to a power transfer mode for operation, wherein the power transfer mode is used to control the second AC port of the flexible interconnection device to supply power to the first AC port of the flexible interconnection device.

[0009] Further, if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time period, switching the flexible interconnection device to the power transfer mode includes: if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time period, determining whether there is an undervoltage module in the flexible interconnection device; if there is an undervoltage module in the flexible interconnection device, charging the undervoltage module in the flexible interconnection device, and switching the flexible interconnection device to the power transfer mode based on the charged undervoltage module; if there is no undervoltage module in the flexible interconnection device, unlocking the first AC port of the flexible interconnection device, and switching the flexible interconnection device to the power transfer mode.

[0010] Furthermore, based on the undervoltage module after charging, switching the flexible interconnection device to the power transfer mode includes: judging whether the voltage value of the undervoltage module after charging is less than a first preset threshold value; if the voltage value of the undervoltage module after charging is less than the first preset threshold value, continuing to charge the undervoltage module in the flexible interconnection device; if the voltage value of the undervoltage module after charging is not less than the first preset threshold value, unlocking the first AC port of the flexible interconnection device, and switching the flexible interconnection device to the power transfer mode.

[0011] Furthermore, before the flexible interconnection device for controlling the AC power grid is switched to the current limiting mode when a fault in the AC power grid is detected, the method further includes: judging whether the AC power grid has a fault according to the voltage value of the first AC port of the flexible interconnection device; if the AC power grid has not failed, controlling the flexible interconnection device to operate in a power mode, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; if the AC power grid has a fault, executing the step of switching the flexible interconnection device for controlling the AC power grid to the current limiting mode.

[0012] Further, judging whether the AC power grid fails based on the voltage value of the first AC port of the flexible interconnection device includes: obtaining the voltage value of the last sampling of the voltage of the first AC port of the flexible interconnection device to obtain a target voltage value of the first AC port; obtaining the voltage value of the first AC port of the flexible interconnection device at the current moment to obtain a current voltage value of the first AC port; calculating the difference between the current voltage value of the first AC port and the target voltage value of the first AC port, and judging whether the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than a second preset threshold; if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than the second preset threshold, determining that the AC power grid fails; if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is not greater than the second preset threshold, determining that the AC power grid does not fail.

[0013] In order to achieve the above-mentioned object, according to another aspect of the present application, a control device for a flexible interconnection device is provided. The device comprises: a first processing unit, which is used to switch the flexible interconnection device for controlling the AC power grid to operate in a current limiting mode when a fault in the AC power grid is detected, and control the flexible interconnection device to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than a preset current value; a first control unit, which is used to control the first AC port of the flexible interconnection device to enter a temporary blocking state according to the voltage value of the first AC port of the flexible interconnection device within the first preset time, and control the first AC port of the flexible interconnection device to be in a temporary blocking state within a second preset time, wherein the first AC port is the AC port corresponding to the AC power grid; a second control unit, which is used to detect the residual voltage of the first AC port of the flexible interconnection device within the second preset time, and control the operation of the flexible interconnection device according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time.

[0014] Further, the first control unit includes: a first judgment subunit, used to judge whether the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within the first preset time length; a first switching subunit, used to switch the flexible interconnection device to a power mode if the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within the first preset time length, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; and a first control subunit, used to control the first AC port of the flexible interconnection device to enter a temporarily locked state if the voltage value of the first AC port of the flexible interconnection device is not equal to the preset voltage value within the first preset time length.

[0015] Further, the second control unit includes: a second judgment subunit, used to judge whether there is a residual voltage at the first AC port of the flexible interconnection device within the second preset time length; a second control subunit, used to control the first AC port of the flexible interconnection device to enter a permanent locked state if there is a residual voltage at the first AC port of the flexible interconnection device within the second preset time length, and control the second AC port of the flexible interconnection device to be in an operating state, wherein the second AC port is an AC port other than the first AC port in the flexible interconnection device; a second switching subunit, used to switch the flexible interconnection device to a transfer power supply mode if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time length, wherein the transfer power supply mode is used to control the second AC port of the flexible interconnection device to supply power to the first AC port of the flexible interconnection device.

[0016] Further, the second switching subunit includes: a first judgment module, used to judge whether there is an undervoltage module in the flexible interconnection device if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time period; a first processing module, used to charge the undervoltage module in the flexible interconnection device if there is an undervoltage module in the flexible interconnection device, and switch the flexible interconnection device to a transfer power supply mode based on the charged undervoltage module; and a second processing module, used to unlock the first AC port of the flexible interconnection device if there is no undervoltage module in the flexible interconnection device, and switch the flexible interconnection device to a transfer power supply mode.

[0017] Furthermore, the first processing module includes: a first judgment submodule, used to judge whether the voltage value of the undervoltage module after charging is less than a first preset threshold; a first charging submodule, used to continue charging the undervoltage module in the flexible interconnection device if the voltage value of the undervoltage module after charging is less than the first preset threshold; a first processing submodule, used to unlock the first AC port of the flexible interconnection device and switch the flexible interconnection device to the power transfer mode if the voltage value of the undervoltage module after charging is not less than the first preset threshold.

[0018] Furthermore, the device also includes: a first judgment unit, used to judge whether the AC power grid has a fault according to the voltage value of the first AC port of the flexible interconnection device before switching the flexible interconnection device used to control the AC power grid to the current limiting mode when a fault in the AC power grid is detected; a third control unit, used to control the flexible interconnection device to operate in a power mode when the AC power grid has not failed, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; and a second processing unit, used to execute the step of switching the flexible interconnection device used to control the AC power grid to the current limiting mode when a fault in the AC power grid occurs.

[0019] Further, the first judgment unit includes: a first acquisition subunit, used to acquire the voltage value of the last sampling of the voltage of the first AC port of the flexible interconnection device to obtain the target voltage value of the first AC port; a second acquisition subunit, used to acquire the voltage value of the first AC port of the flexible interconnection device at the current moment to obtain the current voltage value of the first AC port; a first processing subunit, used to calculate the difference between the current voltage value of the first AC port and the target voltage value of the first AC port, and determine whether the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than a second preset threshold; a first determination subunit, used to determine that the AC power grid has a fault if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than the second preset threshold; and a second determination subunit, used to determine that the AC power grid has not a fault if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is not greater than the second preset threshold.

[0020] In order to achieve the above objective, according to another aspect of the present application, a computer-readable storage medium is provided, wherein the storage medium stores a program, wherein the program executes any one of the above-mentioned control methods for the flexible interconnection device.

[0021] In order to achieve the above-mentioned purpose, according to another aspect of the present application, an electronic device is provided, which includes one or more processors and a memory, and the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement any one of the above-mentioned control methods of the flexible interconnection device.

[0022] Through the present application, the following steps are adopted: when a fault in the AC power grid is detected, the flexible interconnection device for controlling the AC power grid is switched to a current limiting mode, and the flexible interconnection device is controlled to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than the preset current value; according to the voltage value of the first AC port of the flexible interconnection device within the first preset time, the first AC port of the flexible interconnection device is controlled to enter a temporary blocking state, and the first AC port of the flexible interconnection device is controlled to be in a temporary blocking state within a second preset time, wherein the first AC port is the AC port corresponding to the AC power grid; the residual voltage of the first AC port of the flexible interconnection device is detected within the second preset time, and the operation of the flexible interconnection device is controlled according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time, so as to solve the problem in the related art that when a fault occurs in the AC power grid, it is difficult to ensure the normal operation of the flexible interconnection device for controlling the AC power grid, resulting in low reliability of the flexible interconnection device. In the present application, when the flexible interconnection device is connected to the grid and detects an AC power grid fault, the flexible interconnection device first switches to a current limiting mode to ensure that the current of the flexible interconnection device does not exceed its own current carrying capacity during the fault period; if the AC voltage is detected to be restored within the delay time t1 (i.e., within the first preset time length), the flexible interconnection device returns to the power mode operation, otherwise it enters a temporarily closed state (i.e., a temporarily locked state); if the AC residual voltage (i.e., the residual voltage of the first AC port) is not detected within the delay time t2 (i.e., within the second preset time length), the flexible interconnection device switches to a power transfer mode operation, and other non-faulty ports supply power to the faulty port, otherwise it enters a permanent lockout. The solution of the present application can meet the needs of the flexible interconnection device for high-reliability power supply and power transfer, ensure that the flexible interconnection device works normally under normal or faulty conditions of the primary system, and can provide power transfer support to the faulty port to achieve continuous power supply to the load, thereby achieving the effect of improving the reliability of the flexible interconnection device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1is a flow chart of a control method of a flexible interconnection device provided in an embodiment of the present application;

[0025] Figure 2 It is a topological schematic diagram of a frequency mixing flexible interconnection device in a frequency mixing flexible interconnection device fault ride-through control method provided in an embodiment of the present application;

[0026] Figure 3 It is a flow chart of a fault ride-through control method of a frequency mixing flexible interconnection device provided according to an embodiment of the present application;

[0027] Figure 4 A control frame of a power mode of a mixed frequency flexible interconnection device fault ride-through control method provided in an embodiment of the present application Figure 1 ;

[0028] Figure 5 A control frame of a power mode of a mixed frequency flexible interconnection device fault ride-through control method provided in an embodiment of the present application Figure 2 ;

[0029] Figure 6 A control frame of a current limiting mode of a fault ride-through control method of a frequency-mixing flexible interconnection device provided in an embodiment of the present application Figure 1 ;

[0030] Figure 7 A control frame of a current limiting mode of a fault ride-through control method of a frequency-mixing flexible interconnection device provided in an embodiment of the present application Figure 2 ;

[0031] Figure 8 A control frame of a power supply transfer mode of a mixed frequency flexible interconnection device fault ride-through control method provided in an embodiment of the present application Figure 1 ;

[0032] Fig. 9 A control frame of a power supply transfer mode of a mixed frequency flexible interconnection device fault ride-through control method provided in an embodiment of the present application Figure 2 ;

[0033] Fig.10 is a schematic diagram of a control device of a flexible interconnection device provided according to an embodiment of the present application;

[0034] Fig.11 is a schematic diagram of an electronic device provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0037] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0038] It should be noted that the relevant information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for display, data for analysis, etc.) involved in this disclosure are all information and data authorized by the user or fully authorized by all parties. For example, an interface is set between this system and the relevant user or organization. Before obtaining relevant information, it is necessary to send an acquisition request to the aforementioned user or organization through the interface, and obtain relevant information after receiving the consent information fed back by the aforementioned user or organization.

[0039] The present invention is described below in conjunction with preferred implementation steps. Figure 1 is a flow chart of a control method of a flexible interconnection device provided in an embodiment of the present application. Figure 1 As shown, the method comprises the following steps:

[0040] Step S101, when a fault in the AC power grid is detected, the flexible interconnection device used to control the AC power grid is switched to a current limiting mode, and the flexible interconnection device is controlled to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than a preset current value.

[0041] For example, in normal operation, the voltage of the AC power grid common connection point (PCC) is monitored in real time to determine whether a fault occurs in the AC power grid; if no fault occurs, the frequency mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) operates in a power mode; when it is determined that a fault occurs in the AC power grid, the frequency mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) switches to a current limiting mode and maintains a delay time t1 (corresponding to the above-mentioned first preset duration).

[0042] Step S102, according to the voltage value of the first AC port of the flexible interconnection device within the first preset time length, controlling the first AC port of the flexible interconnection device to enter a temporarily locked state, and controlling the first AC port of the flexible interconnection device to be in a temporarily locked state within a second preset time length, wherein the first AC port is an AC port corresponding to the AC power grid.

[0043] For example, within the delay time t1 (corresponding to the above-mentioned first preset time length), it is detected whether the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) at the AC power supply end has returned to a normal value. If the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) has returned within the delay time t1 (corresponding to the above-mentioned first preset time length), the frequency mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) switches to power mode operation; if after the delay t1 (corresponding to the above-mentioned first preset time length), the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) has not returned to a normal value, the flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to enter a temporary closed state and maintain the temporary closed state delay time t2 (corresponding to the above-mentioned second preset time length). Moreover, the above-mentioned temporary locked state means that the flexible interconnection device is controlled to be in a locked state within the second preset time length, and the flexible interconnection device can be unlocked after the second preset time length, or the flexible interconnection device is controlled to continue to be in a locked state.

[0044] Step S103 , detecting a residual voltage of the first AC port of the flexible interconnection device within a second preset time period, and controlling the flexible interconnection device to operate according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time period.

[0045] For example, within the delay time t2 (corresponding to the above-mentioned second preset time length), it is detected whether the PCC (corresponding to the voltage value of the above-mentioned first AC port) has residual voltage (corresponding to the above-mentioned residual voltage). If the residual voltage (corresponding to the above-mentioned residual voltage) appears within the delay time t2 (corresponding to the above-mentioned second preset time length), the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to be permanently locked; if after the delay t2 (corresponding to the above-mentioned second preset time length), the PCC does not detect the residual voltage (corresponding to the above-mentioned residual voltage), the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) can be switched to the power transfer mode, and the power transfer mode operation means that the other non-faulty ports of the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) supply power to the faulty port.

[0046] Through the above steps S101 to S103, when the flexible interconnection device is connected to the grid and detects an AC power grid fault, the flexible interconnection device first switches to the current limiting mode to ensure that the current of the flexible interconnection device does not exceed its own current carrying capacity during the fault period; if the AC voltage is detected to be restored within the delay time t1 (i.e., within the first preset time length), the flexible interconnection device returns to the power mode operation, otherwise it enters a temporarily closed state (i.e., a temporarily locked state); if the AC residual voltage (i.e., the residual voltage of the first AC port) is not detected within the delay time t2 (i.e., within the second preset time length), the flexible interconnection device switches to the power transfer mode operation, and other non-faulty ports supply power to the faulty port, otherwise it enters a permanent lock. The solution of the present application can meet the needs of the flexible interconnection device for high-reliability power supply and power transfer, ensure that the flexible interconnection device works normally under normal or faulty conditions of the primary system, and can transfer power to the faulty port to achieve continuous power supply to the load, thereby achieving the effect of improving the reliability of the flexible interconnection device.

[0047] Optionally, in the control method of the flexible interconnection device provided in the embodiment of the present application, when a fault in the AC power grid is detected, before the flexible interconnection device for controlling the AC power grid is switched to the current limiting mode for operation, the method further includes: judging whether the AC power grid has failed based on the voltage value of the first AC port of the flexible interconnection device; when the AC power grid has not failed, controlling the flexible interconnection device to operate in a power mode, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; when a fault in the AC power grid occurs, executing the step of switching the flexible interconnection device for controlling the AC power grid to the current limiting mode for operation.

[0048] For example, it is possible to determine whether an AC power grid fault occurs based on the AC power grid common connection point (PCC) voltage (corresponding to the voltage value of the first AC port mentioned above) monitored in real time; if the AC power grid does not fail, the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) operates in a power mode, that is, the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to operate normally; if the AC power grid fails, the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) switches to a current limiting mode.

[0049] Through the above solution, it is possible to quickly and accurately determine whether a fault occurs in the AC power grid based on the detected voltage at the common connection point of the AC power grid.

[0050] Optionally, in the control method of the flexible interconnection device provided in the embodiment of the present application, judging whether the AC power grid fails according to the voltage value of the first AC port of the flexible interconnection device includes: obtaining the voltage value of the last sampling of the voltage of the first AC port of the flexible interconnection device to obtain a target voltage value of the first AC port; obtaining the voltage value of the first AC port of the flexible interconnection device at the current moment to obtain a current voltage value of the first AC port; calculating the difference between the current voltage value of the first AC port and the target voltage value of the first AC port, and judging whether the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than a second preset threshold; if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than the second preset threshold, determining that the AC power grid fails; if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is not greater than the second preset threshold, determining that the AC power grid does not fail.

[0051] For example, it can be determined whether the PCC voltage (corresponding to the voltage value of the first AC port mentioned above) drops instantaneously; if the PCC voltage (corresponding to the voltage value of the first AC port mentioned above) drops instantaneously, it can be determined that the AC power grid fails; if the PCC voltage (corresponding to the voltage value of the first AC port mentioned above) does not drop instantaneously, it can be determined that the AC power grid does not fail.

[0052] For example, when judging whether the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) drops instantaneously, the judgment can be made based on the difference between the voltage value of the last sampled PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) (corresponding to the target voltage value of the above-mentioned first AC port) and the PCC voltage at the current moment (corresponding to the current voltage value of the above-mentioned first AC port). For example, when the difference between the voltage value of the last sampled PCC voltage (corresponding to the voltage value of the first AC port) (corresponding to the target voltage value of the first AC port) and the PCC voltage at the current moment (corresponding to the current voltage value of the first AC port) is greater than 22 volts (corresponding to the second preset threshold), it can be determined that the PCC voltage (corresponding to the voltage value of the first AC port) drops instantaneously, that is, it is judged that a fault has occurred in the AC power grid; when the difference between the voltage value of the last sampled PCC voltage (corresponding to the target voltage value of the first AC port) and the PCC voltage at the current moment (corresponding to the current voltage value of the first AC port) is not greater than 22 volts (corresponding to the second preset threshold), it can be determined that the PCC voltage (corresponding to the voltage value of the first AC port) does not drop instantaneously, that is, it is judged that no fault has occurred in the AC power grid.

[0053] Through the above scheme, it is possible to quickly and accurately determine whether a fault occurs in the AC power grid according to the voltage values ​​obtained by sampling the voltage at the common connection point of the AC power grid twice.

[0054] Optionally, in the control method of the flexible interconnection device provided in the embodiment of the present application, according to the voltage value of the first AC port of the flexible interconnection device within the first preset time length, controlling the first AC port of the flexible interconnection device to enter a temporarily locked state includes: judging whether the voltage value of the first AC port of the flexible interconnection device is equal to a preset voltage value within the first preset time length; if the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within the first preset time length, switching the flexible interconnection device to a power mode for operation, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; if the voltage value of the first AC port of the flexible interconnection device is not equal to the preset voltage value within the first preset time length, controlling the first AC port of the flexible interconnection device to enter a temporarily locked state.

[0055] For example, within the delay time t1 (corresponding to the above-mentioned first preset time length), it is detected whether the PCC voltage at the AC power supply end (corresponding to the voltage value of the above-mentioned first AC port) returns to a normal value (corresponding to the above-mentioned preset voltage value), that is, within the delay time t1 (corresponding to the above-mentioned first preset time length), it is detected whether the PCC voltage at the AC power supply end (corresponding to the voltage value of the above-mentioned first AC port) is equal to 220 volts (corresponding to the above-mentioned preset voltage value); if the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) is restored within the delay time t1 (corresponding to the above-mentioned first preset time length), that is, within the delay time t1 (corresponding to the above-mentioned first preset time length), the PCC voltage at the AC power supply end (corresponding to the above-mentioned first AC port) is detected. If the voltage value of the AC power supply end (corresponding to the voltage value of the first AC port) is equal to 220 volts (corresponding to the above-mentioned preset voltage value), the frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to switch to the power mode operation; if after the delay t1 (corresponding to the above-mentioned first preset duration), the PCC voltage (corresponding to the voltage value of the first AC port) has not returned to the normal value (corresponding to the above-mentioned preset voltage value), that is, the AC power supply end PCC voltage (corresponding to the voltage value of the first AC port) is not equal to 220 volts (corresponding to the above-mentioned preset voltage value) within the delay time t1 (corresponding to the above-mentioned first preset duration), the frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to enter a temporary closed state (corresponding to the above-mentioned temporary locked state). Moreover, the above-mentioned temporary locked state means that the flexible interconnection device is controlled to be in a locked state within the second preset duration, and the flexible interconnection device can be unlocked after the second preset duration, or the flexible interconnection device is controlled to continue to be in a locked state.

[0056] Through the above scheme, according to the detected PCC voltage at the AC power supply end, the frequency mixing flexible interconnection device can be quickly and accurately controlled to enter a temporary locking state.

[0057] Optionally, in the control method of the flexible interconnect device provided in the embodiment of the present application, according to the residual voltage of the first AC port of the flexible interconnect device within the second preset time length, controlling the operation of the flexible interconnect device includes: judging whether there is a residual voltage at the first AC port of the flexible interconnect device within the second preset time length; if there is a residual voltage at the first AC port of the flexible interconnect device within the second preset time length, controlling the first AC port of the flexible interconnect device to enter a permanent locked state, and controlling the second AC port of the flexible interconnect device to be in an operating state, wherein the second AC port is an AC port other than the first AC port in the flexible interconnect device; if there is no residual voltage at the first AC port of the flexible interconnect device within the second preset time length, switching the flexible interconnect device to a power transfer mode for operation, wherein the power transfer mode is used to control the second AC port of the flexible interconnect device to supply power to the first AC port of the flexible interconnect device.

[0058] For example, within the delay time t2 (corresponding to the above-mentioned second preset time length), it is detected whether the PCC (corresponding to the voltage value of the above-mentioned first AC port) has residual voltage (corresponding to the above-mentioned residual voltage); if the residual voltage (corresponding to the above-mentioned residual voltage) appears within the delay time t2 (corresponding to the above-mentioned second preset time length), the fault port (i.e., the port corresponding to the faulty AC power grid, corresponding to the above-mentioned first AC port) of the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to be permanently locked, and the ports (corresponding to the above-mentioned second AC port) other than the fault port (i.e., the port corresponding to the faulty AC power grid) in the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) are controlled to operate normally; if after the delay t2 (corresponding to the above-mentioned second preset time length), the PCC (corresponding to the voltage value of the above-mentioned first AC port) does not detect the residual voltage (corresponding to the above-mentioned residual voltage), the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) can be switched to the power transfer mode, and the power transfer mode operation is that the other non-faulty ports of the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) supply power to the faulty port.

[0059] Through the above scheme, according to whether there is residual voltage in the PCC voltage at the AC power supply end, the frequency mixing flexible interconnection device can be quickly and accurately controlled to switch to the power supply transfer mode.

[0060] Optionally, in the control method of the flexible interconnection device provided in the embodiment of the present application, if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time length, switching the flexible interconnection device to the power transfer mode includes: if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time length, determining whether there is an undervoltage module in the flexible interconnection device; if there is an undervoltage module in the flexible interconnection device, charging the undervoltage module in the flexible interconnection device, and switching the flexible interconnection device to the power transfer mode based on the charged undervoltage module; if there is no undervoltage module in the flexible interconnection device, unlocking the first AC port of the flexible interconnection device, and switching the flexible interconnection device to the power transfer mode.

[0061] For example, if after a delay of t2 (corresponding to the second preset time length mentioned above), the PCC (corresponding to the voltage value of the first AC port mentioned above) does not detect the residual voltage (corresponding to the residual voltage mentioned above), it can be determined whether there is undervoltage based on the DC voltage of each power module. If there is an undervoltage module, the controllable charging process is entered, and according to the charged power module, the mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is switched to the power transfer mode; if there is no undervoltage module, the mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) can be directly switched to the power transfer mode.

[0062] In summary, by charging the undervoltage power module, the frequency-mixing flexible interconnect device can be quickly and accurately controlled to switch to the power supply mode.

[0063] Optionally, in the control method of the flexible interconnect device provided in the embodiment of the present application, based on the undervoltage module after charging, switching the flexible interconnect device to the power transfer mode includes: judging whether the voltage value of the undervoltage module after charging is less than a first preset threshold value; if the voltage value of the undervoltage module after charging is less than the first preset threshold value, continuing to charge the undervoltage module in the flexible interconnect device; if the voltage value of the undervoltage module after charging is not less than the first preset threshold value, unlocking the first AC port of the flexible interconnect device, and switching the flexible interconnect device to the power transfer mode.

[0064] For example, when charging an undervoltage power module, it can be determined first whether the undervoltage power module has completed charging, that is, whether the voltage value of the undervoltage module after charging is less than 200 volts (corresponding to the above-mentioned first preset threshold); if the undervoltage power module has not completed charging, that is, the voltage value of the undervoltage module after charging is less than 200 volts (corresponding to the above-mentioned first preset threshold), the undervoltage module can continue to be charged until the charging of the undervoltage module is completed, the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to be unlocked, and the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to switch to the power transfer mode; if the undervoltage power module has completed charging, that is, the voltage value of the undervoltage module after charging is not less than 200 volts (corresponding to the above-mentioned first preset threshold), the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) can be unlocked, and the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is controlled to switch to the power transfer mode.

[0065] Through the above scheme, according to the charging status of the undervoltage module, the frequency mixing flexible interconnection device can be quickly and accurately controlled to switch to the power supply mode.

[0066] For example, this embodiment provides a fault ride-through control method for a frequency-mixing flexible interconnection device. The frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) includes N AC ports (N≥2), including 1 main port and N-1 secondary ports; any secondary port and the main port are bridged by a cascaded H bridge, and a three-phase resonance module is connected in series on the port; the main port is connected to the AC side of the cascaded power electronic transformer, and the DC side of the cascaded power electronic transformer is connected to a DC port. When the frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is grid-connected and detects an AC grid fault, the device first switches to a current limiting mode to ensure that the current of the flexible interconnection device does not exceed its own current carrying capacity during the fault; if the AC voltage is detected to be restored within the delay time t1 (corresponding to the above-mentioned first preset time length), the device returns to the power mode operation, otherwise it enters a temporarily closed state; if the AC residual voltage is not detected within the delay time t2 (corresponding to the above-mentioned second preset time length), the device switches to a power transfer mode operation, and other non-faulty ports supply power to the faulty port, otherwise it enters a permanent lockout. The method provided in this embodiment can meet the needs of the mixed-frequency flexible interconnection device for high-reliability power supply and power flow transfer, ensure that the flexible interconnection device works normally under normal or fault conditions of the primary system, and transfer support to the faulty port to achieve continuous power supply to the load.

[0067] For example, in order to meet the needs of high-reliability power supply and power flow transfer, the flexible interconnection device needs to have the ability to effectively respond to AC system failures. The flexible interconnection device body control system should ensure that the flexible interconnection device works normally under normal or faulty conditions of the primary system, and in any case, the flexible interconnection device should not be damaged due to improper operation of the body control system.

[0068] Moreover, the purpose of this embodiment is to provide a fault-crossing control method for a hybrid flexible interconnection device. In view of the response requirements of the hybrid flexible interconnection device for flexible distribution networks to AC faults, a control method is proposed when each AC fault occurs, thereby ensuring the fault-crossing capability and reliability of the hybrid flexible interconnection device when an AC power grid fault occurs.

[0069] For example, in this embodiment, a fault ride-through control method for a frequency mixing flexible interconnection device includes:

[0070] A frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device): comprising N AC ports (N≥2), wherein AC port 1 is a main port and the remaining N-1 ports are sub-ports; any sub-port and the main port are bridged by a cascaded H-bridge (CHB), and a three-phase resonance module is connected in series on the port, the three-phase resonance module is a capacitor and inductor element with resonance function, and the resonance frequency is significantly greater than the power frequency; the main port is connected to the AC side of a cascaded power electronic transformer (PET), and the DC side of the cascaded PET is connected to the DC port.

[0071] Step 1: Real-time monitoring of the voltage of the AC grid common connection point (PCC) (corresponding to the voltage value of the first AC port mentioned above) to determine whether the AC grid has a fault; if no fault occurs, the frequency mixing flexible interconnection device operates in power mode;

[0072] Step 2: When it is determined that the AC power grid fails, the frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) switches to the current-limiting mode and maintains the delay time t1 (corresponding to the above-mentioned first preset time length). During the delay time (corresponding to the above-mentioned first preset time length), it detects whether the PCC voltage at the AC power supply end (corresponding to the voltage value of the above-mentioned first AC port) has returned to normal. If the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) is restored within the delay time t1 (corresponding to the above-mentioned first preset time length), the frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) switches to the power mode; if after the delay time t1 (corresponding to the above-mentioned first preset time length), the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) is restored, the frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) switches to the power mode. After t1 (corresponding to the first preset time length), the PCC voltage (corresponding to the voltage value of the first AC port) has not returned to the normal value, the flexible interconnection device is controlled to enter the temporary closed state and maintain the temporary closed state for a delay time t2 (corresponding to the second preset time length), and during the delay time (corresponding to the second preset time length), the PCC (corresponding to the voltage value of the first AC port) is detected to see if there is residual voltage (corresponding to the residual voltage). If there is residual voltage (corresponding to the residual voltage) within the delay time t2 (corresponding to the second preset time length), the frequency mixing flexible interconnection device (corresponding to the flexible interconnection device) is permanently locked;

[0073] Step 3: If after a delay of t2 (corresponding to the second preset time length mentioned above), the PCC (corresponding to the voltage value of the first AC port mentioned above) does not detect the residual voltage (corresponding to the residual voltage mentioned above), it is determined whether there is undervoltage based on the DC voltage of each power module. If there is an undervoltage module, the controllable charging process is entered until the controlled charging is completed, and the mixed frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is unlocked and switched to the power supply mode.

[0074] For example, this embodiment further includes the following preferred embodiments.

[0075] In step 1, when the mixing frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) operates in power mode, preferably, the AC side control strategy of the cascaded PET includes industrial frequency control and intermediate frequency control: the industrial frequency control is a cascaded double closed-loop control, in which the industrial frequency outer loop controls the bus voltage and the power flow of the main port, and the industrial frequency inner loop controls the three-phase fundamental current; the intermediate frequency modulation signal is an intermediate frequency square wave generated by an open loop, and the intermediate frequency modulation signal is superimposed on the industrial frequency modulation signal to control the cascaded PET.

[0076] Preferably, the DC side of the cascaded PET is single phase shift controlled.

[0077] Preferably, the control strategy of CHB includes power frequency control and medium frequency control: the power frequency control is a cascaded double closed-loop control, in which the power frequency outer loop controls the flow of the corresponding secondary port, and the power frequency inner loop controls the three-phase fundamental current; the medium frequency control is a cascaded double closed-loop control, in which the medium frequency outer loop controls the CHB DC capacitor voltage, and the medium frequency inner loop controls the phase of the medium frequency circulating current to be in phase or inverse phase with the medium frequency voltage to charge or discharge the capacitor. The medium frequency modulation signal is superimposed on the power frequency modulation signal to control the CHB.

[0078] In step 2, when a fault in the AC power grid is detected, preferably, the control mode of the CHB corresponding to the cascaded PET and the AC port where no fault occurs is maintained the same as the power mode; the intermediate frequency control of the CHB corresponding to the faulty port is maintained the same as the power mode, the active power instruction Pref and the reactive power instruction Qref of the power frequency control outer loop are set to zero, and the power frequency modulation wave instruction is generated and superimposed with the intermediate frequency modulation signal to control the CHB.

[0079] In step 3, when the frequency mixing flexible device (corresponding to the above-mentioned flexible interconnection device) operates in the power transfer mode, preferably, the control mode of the CHB corresponding to the cascaded PET and the AC port where no fault occurs is maintained the same as the power mode; the intermediate frequency control of the CHB corresponding to the faulty port is maintained the same as the power mode, the industrial frequency modulation wave is set to a constant voltage value, the industrial frequency modulation signal is superimposed on the intermediate frequency modulation signal, and the CHB is controlled.

[0080] To sum up, this embodiment realizes AC fault ride-through of a flexible interconnection device in a multi-port interconnection scenario through a fault ride-through control method for a frequency-mixing flexible interconnection device. Compared with the existing solution, the frequency-mixing flexible interconnection device can save switching devices and passive components, has better economy and higher power density, and has strong scalability, and is easy to expand to different numbers of ports. The fault ride-through control strategy has simple and effective judgment conditions, rapid mode conversion response, and reliable removal, which can improve the reliability of the frequency-mixing flexible interconnection device and has good application prospects.

[0081] For example, Figure 2 is a topological diagram of a frequency mixing flexible interconnection device in a frequency mixing flexible interconnection device fault ride-through control method provided in an embodiment of the present application, such as Figure 2As shown, this embodiment relates to a frequency-mixing flexible interconnection device, which (corresponding to the above-mentioned flexible interconnection device) comprises a cascaded PET and N-1 CHBs, connected to N AC ports and 1 DC port. Among them, AC port 1 is the main port, and the remaining N-1 ports are sub-ports; there is a CHB jumper between any sub-port and the main port, and the port is connected in series with a three-phase resonance module, which is an LC element with a resonance function, and the resonance frequency is significantly greater than the power frequency, and is used to provide a flow path for the intermediate frequency circulation; the main port is connected to the AC side of the cascaded PET, and the DC side of the cascaded PET is connected to the DC port.

[0082] Moreover, both the cascaded PET and CHB use mixed frequency modulation, and the modulation signal includes an industrial frequency component and an intermediate frequency component, wherein the frequency of the intermediate frequency modulation component is the same as the resonant frequency of the resonant module.

[0083] For example, Figure 3 is a flow chart of a method for controlling a fault ride-through of a frequency mixing flexible interconnection device according to an embodiment of the present application. Figure 3 As shown, the control process includes the following steps:

[0084] Step 1: In the normal operation state, the PCC voltage (corresponding to the voltage value of the first AC port) is monitored in real time to determine whether the AC power grid fails; if no failure occurs, the frequency mixing flexible interconnection device (corresponding to the flexible interconnection device) operates in the power mode;

[0085] For example, Figure 4 A control frame of a power mode of a mixed frequency flexible interconnection device fault ride-through control method provided in an embodiment of the present application Figure 1 , Figure 5 A control frame of a power mode of a mixed frequency flexible interconnection device fault ride-through control method provided in an embodiment of the present application Figure 2 , so Figure 4 and Figure 5 As shown, the power mode control block diagram includes two parts: cascade PET control and CHB control. The cascade PET power mode control includes but is not limited to: the PET reactive power command Q 1ref The DC voltage command value is sent to the flexible interconnection device by the upper controller. The DC voltage U is adjusted by PI control. dc1 and reactive power Q1. The outputs of the DC voltage outer loop and the reactive power outer loop are the PET d-axis current command I dref1 and q-axis current command I qref1 , and then through the d-axis current I d1 and q-axis current I q1 The inner loop control obtains the industrial frequency modulation wave; U MFrefThe intermediate frequency modulation wave is given by the open loop, which is superimposed on the power frequency modulation wave, and then the PET interphase balanced compensation voltage u is superimposed through interphase balanced control. bal1ABC The CHB power mode control includes but is not limited to: CHB active power instruction P 2ref and reactive power command Q 2ref It is sent to the flexible interconnection device by the upper controller, and the active power P2 and reactive power Q2 are adjusted through PI control. The outputs of the active power outer loop and the reactive power outer loop are the d-axis current command I of CHB respectively. dref2 and q-axis current command I qref2 , and then through the d-axis current I d2 and q-axis current I q2 The inner loop control obtains the industrial frequency modulation wave; the intermediate frequency current command I is obtained through the CHB DC capacitor voltage outer loop PI control. MFref , and then control the intermediate frequency current I through the intermediate frequency current proportional controller cir , superimposed feedforward quantity -U MFref Output CHB intermediate frequency modulation wave; superimpose the intermediate frequency modulation wave with the power frequency modulation wave, and then superimpose the CHB interphase balanced compensation voltage u through interphase balanced control bal2ABC Get the modulation signal of CHB. In addition, Figure 4 E in d1 is the d-axis grid voltage at AC port 1, E q1 is the q-axis grid voltage at AC port 1, and Figure 4 and Figure 5 wL f is the feedforward voltage term, Figure 5 E in d2 is the d-axis grid voltage at AC port 2, E' d2 is the d-axis voltage difference between AC port 2 and AC port 1, E' q2 is the q-axis voltage difference between AC port 2 and AC port 1, Figure 4 u dc1Aave ,u dc1Bave ,u dc1Cave They are the average voltages of the A, B, and C phase modules of the PET bridge arm, Figure 5 u dc2Aave ,u dc2Bave ,u dc2Cave They are the average voltages of the A, B, and C phase modules of the CHB bridge arm respectively.

[0086] Step 2: When it is determined that the AC power grid fails, the frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) switches to the current-limiting mode and maintains the delay time t1 (corresponding to the above-mentioned first preset time length). During the delay time (corresponding to the above-mentioned first preset time length), it is detected whether the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) returns to the normal value. If the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) is restored within the delay time t1 (corresponding to the above-mentioned first preset time length), the frequency-mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) switches to the power mode; if after the delay t1 (corresponding to the above-mentioned first preset time length), if the PCC voltage (corresponding to the voltage value of the above-mentioned first AC port) still does not return to the normal value, the flexible interconnection device is controlled to enter the temporary closed state and maintain the temporary closed state for a delay time t2 (corresponding to the above-mentioned second preset time length), and whether the PCC (corresponding to the voltage value of the above-mentioned first AC port) has residual voltage (corresponding to the above-mentioned residual voltage) is detected within the delay time (corresponding to the above-mentioned second preset time length). If the residual voltage (corresponding to the above-mentioned residual voltage) appears within the delay time t2 (corresponding to the above-mentioned second preset time length), the frequency mixing flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is permanently locked;

[0087] For example, Figure 6 A control frame of a current limiting mode of a fault ride-through control method of a frequency-mixing flexible interconnection device provided in an embodiment of the present application Figure 1 , Figure 7 A control frame of a current limiting mode of a fault ride-through control method of a frequency-mixing flexible interconnection device provided in an embodiment of the present application Figure 2 , so Figure 6 and Figure 7 As shown in the figure, the current limiting mode control block diagram includes two parts: cascade PET control and CHB control. The cascade PET current limiting mode control includes but is not limited to: the PET reactive power command Q 1ref The DC voltage command value is sent to the flexible interconnection device by the upper controller. The DC voltage U is adjusted by PI control. dc1 and reactive power Q1. The outputs of the DC voltage outer loop and the reactive power outer loop are the PET d-axis current command I dref1 and q-axis current command I qref1 , and then through the d-axis current I d1 and q-axis current I q1 The inner loop control obtains the power frequency modulation wave; the given intermediate frequency modulation wave U MFref It is superimposed on the power frequency modulation wave, and then the PET interphase balanced compensation voltage u is superimposed through interphase balanced control bal1ABCThe CHB current limiting mode control includes but is not limited to: the active power command and reactive power command of the CHB are 0, and the outputs of the active power outer loop and the reactive power outer loop are the CHB d-axis current command I dref2 and q-axis current command I qref2 , and then through the d-axis current I d2 and q-axis current I q2 The inner loop control obtains the industrial frequency modulation wave; the intermediate frequency current command I is obtained through the CHB DC capacitor voltage outer loop PI control. MFref , and then control the intermediate frequency current I through the intermediate frequency current proportional controller cir , superimposed feedforward quantity -U MFref Output CHB intermediate frequency modulation wave; superimpose the intermediate frequency modulation wave with the power frequency modulation wave, and then superimpose the CHB interphase balanced compensation voltage u through interphase balanced control bal2ABC Get the modulation signal of CHB.

[0088] Step 3: After a delay of t2 (corresponding to the second preset time length mentioned above), the PCC (corresponding to the voltage value of the first AC port mentioned above) does not detect the residual voltage (corresponding to the residual voltage mentioned above), and determines whether there is undervoltage based on the DC voltage of each power module. If there is an undervoltage module, the controllable charging process is entered until the controlled charging is completed, and the mixed frequency flexible interconnection device (corresponding to the above-mentioned flexible interconnection device) is unlocked and switched to the power supply mode.

[0089] For example, Figure 8 A control frame of a power supply transfer mode of a mixed frequency flexible interconnection device fault ride-through control method provided in an embodiment of the present application Figure 1 , Fig. 9 A control frame of a power supply transfer mode of a mixed frequency flexible interconnection device fault ride-through control method provided in an embodiment of the present application Figure 2 , so Figure 8 and Fig. 9 As shown, the control block diagram of the power transfer mode includes two parts: cascade PET control and CHB control. The cascade PET power transfer mode control includes but is not limited to: the reactive power instruction Q 1ref The DC voltage command value is sent to the flexible interconnection device by the upper controller. The DC voltage U is adjusted by PI control. dc1 and reactive power Q1. The outputs of the DC voltage outer loop and the reactive power outer loop are the PET d-axis current command I dref1 and q-axis current command I qref1 , and then through the d-axis current I d1 and q-axis current I q1 The inner loop control obtains the power frequency modulation wave; the given intermediate frequency modulation wave U MFrefIt is superimposed on the power frequency modulation wave, and then the PET interphase balanced compensation voltage u is superimposed through interphase balanced control bal1ABC The CHB power supply mode control includes but is not limited to: obtaining the intermediate frequency current command I through the CHB DC capacitor voltage outer loop PI control MFref , and then control the intermediate frequency current I through the intermediate frequency current proportional controller cir , superimposed feedforward quantity -U MFref Output CHB intermediate frequency modulation wave; compare the intermediate frequency modulation wave with the fixed value u0 and the interphase balance compensation voltage u output by the interphase balance controller bal2ABC Superposition can obtain the modulation signal of CHB.

[0090] In summary, the control method of the flexible interconnection device provided in the embodiment of the present application switches the flexible interconnection device for controlling the AC power grid to operate in a current limiting mode when a fault in the AC power grid is detected, and controls the flexible interconnection device to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than the preset current value; according to the voltage value of the first AC port of the flexible interconnection device within the first preset time, the first AC port of the flexible interconnection device is controlled to enter a temporary blocking state, and the first AC port of the flexible interconnection device is controlled to be in a temporary blocking state within a second preset time, wherein the first AC port is the AC port corresponding to the AC power grid; the residual voltage of the first AC port of the flexible interconnection device is detected within the second preset time, and the operation of the flexible interconnection device is controlled according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time, thereby solving the problem in the related art that when a fault occurs in the AC power grid, it is difficult to ensure that the flexible interconnection device for controlling the AC power grid operates normally, resulting in low reliability of the flexible interconnection device. In the present application, when the flexible interconnection device is connected to the grid and detects an AC power grid fault, the flexible interconnection device first switches to a current limiting mode to ensure that the current of the flexible interconnection device does not exceed its own current carrying capacity during the fault period; if the AC voltage is detected to be restored within the delay time t1 (i.e., within the first preset time length), the flexible interconnection device returns to the power mode operation, otherwise it enters a temporarily closed state (i.e., a temporarily locked state); if the AC residual voltage (i.e., the residual voltage of the first AC port) is not detected within the delay time t2 (i.e., within the second preset time length), the flexible interconnection device switches to a power transfer mode operation, and other non-faulty ports supply power to the faulty port, otherwise it enters a permanent lockout. The solution of the present application can meet the needs of the flexible interconnection device for high-reliability power supply and power transfer, ensure that the flexible interconnection device works normally under normal or faulty conditions of the primary system, and can provide power transfer support to the faulty port to achieve continuous power supply to the load, thereby achieving the effect of improving the reliability of the flexible interconnection device.

[0091] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0092] The embodiment of the present application also provides a control device for a flexible interconnection device. It should be noted that the control device for a flexible interconnection device in the embodiment of the present application can be used to execute the control method for a flexible interconnection device provided in the embodiment of the present application. The control device for a flexible interconnection device provided in the embodiment of the present application is introduced below.

[0093] Fig.10 Schematic diagram of a control device for a flexible interconnection device according to an embodiment of the present application. Fig.10 As shown, the device includes: a first processing unit 1001, a first control unit 1002 and a second control unit 1003.

[0094] Specifically, the first processing unit 1001 is used to switch the flexible interconnection device used to control the AC power grid to operate in a current limiting mode when a fault in the AC power grid is detected, and control the flexible interconnection device to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than a preset current value;

[0095] The first control unit 1002 is used to control the first AC port of the flexible interconnection device to enter a temporary blocking state according to the voltage value of the first AC port of the flexible interconnection device within a first preset time period, and control the first AC port of the flexible interconnection device to be in a temporary blocking state within a second preset time period, wherein the first AC port is an AC port corresponding to the AC power grid;

[0096] The second control unit 1003 is used to detect the residual voltage of the first AC port of the flexible interconnection device within a second preset time period, and control the operation of the flexible interconnection device according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time period.

[0097] In summary, the control device of the flexible interconnection device provided in the embodiment of the present application switches the flexible interconnection device for controlling the AC power grid to the current limiting mode when a fault in the AC power grid is detected by the first processing unit 1001, and controls the flexible interconnection device to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than the preset current value; the first control unit 1002 controls the first AC port of the flexible interconnection device to enter a temporary blocking state according to the voltage value of the first AC port of the flexible interconnection device within the first preset time, and controls the first AC port of the flexible interconnection device to be in a temporary blocking state within a second preset time, wherein the first AC port is the AC port corresponding to the AC power grid; the second control unit 1003 detects the residual voltage of the first AC port of the flexible interconnection device within the second preset time, and controls the operation of the flexible interconnection device according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time, thereby solving the problem in the related art that it is difficult to ensure the normal operation of the flexible interconnection device for controlling the AC power grid when a fault occurs in the AC power grid, resulting in low reliability of the flexible interconnection device. In the present application, when the flexible interconnection device is connected to the grid and detects an AC power grid fault, the flexible interconnection device first switches to a current limiting mode to ensure that the current of the flexible interconnection device does not exceed its own current carrying capacity during the fault period; if the AC voltage is detected to be restored within the delay time t1 (i.e., within the first preset time length), the flexible interconnection device returns to the power mode operation, otherwise it enters a temporarily closed state (i.e., a temporarily locked state); if the AC residual voltage (i.e., the residual voltage of the first AC port) is not detected within the delay time t2 (i.e., within the second preset time length), the flexible interconnection device switches to a power transfer mode operation, and other non-faulty ports supply power to the faulty port, otherwise it enters a permanent lockout. The solution of the present application can meet the needs of the flexible interconnection device for high-reliability power supply and power transfer, ensure that the flexible interconnection device works normally under normal or faulty conditions of the primary system, and can provide power transfer support to the faulty port to achieve continuous power supply to the load, thereby achieving the effect of improving the reliability of the flexible interconnection device.

[0098] Optionally, in the control device of the flexible interconnection device provided in the embodiment of the present application, the first control unit includes: a first judgment subunit, used to judge whether the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within a first preset time length; a first switching subunit, used to switch the flexible interconnection device to a power mode if the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within the first preset time length, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; and a first control subunit, used to control the first AC port of the flexible interconnection device to enter a temporarily locked state if the voltage value of the first AC port of the flexible interconnection device is not equal to the preset voltage value within the first preset time length.

[0099] Optionally, in the control device of the flexible interconnect device provided in the embodiment of the present application, the second control unit includes: a second judgment subunit, used to judge whether there is a residual voltage at the first AC port of the flexible interconnect device within a second preset time length; a second control subunit, used to control the first AC port of the flexible interconnect device to enter a permanent locked state if there is a residual voltage at the first AC port of the flexible interconnect device within the second preset time length, and control the second AC port of the flexible interconnect device to be in an operating state, wherein the second AC port is an AC port other than the first AC port in the flexible interconnect device; a second switching subunit, used to switch the flexible interconnect device to a power transfer mode if there is no residual voltage at the first AC port of the flexible interconnect device within the second preset time length, wherein the power transfer mode is used to control the second AC port of the flexible interconnect device to supply power to the first AC port of the flexible interconnect device.

[0100] Optionally, in the control device of the flexible interconnection device provided in the embodiment of the present application, the second switching subunit includes: a first judgment module, which is used to judge whether there is an undervoltage module in the flexible interconnection device if there is no residual voltage at the first AC port of the flexible interconnection device within a second preset time period; a first processing module, which is used to charge the undervoltage module in the flexible interconnection device if there is an undervoltage module in the flexible interconnection device, and switch the flexible interconnection device to a power transfer mode based on the charged undervoltage module; and a second processing module, which is used to unlock the first AC port of the flexible interconnection device if there is no undervoltage module in the flexible interconnection device, and switch the flexible interconnection device to a power transfer mode.

[0101] Optionally, in the control device of the flexible interconnection device provided in the embodiment of the present application, the first processing module includes: a first judgment submodule, used to judge whether the voltage value of the undervoltage module after charging is less than a first preset threshold value; a first charging submodule, used to continue charging the undervoltage module in the flexible interconnection device if the voltage value of the undervoltage module after charging is less than the first preset threshold value; a first processing submodule, used to unlock the first AC port of the flexible interconnection device if the voltage value of the undervoltage module after charging is not less than the first preset threshold value, and switch the flexible interconnection device to the power transfer mode.

[0102] Optionally, in the control device of the flexible interconnection device provided in the embodiment of the present application, the device also includes: a first judgment unit, used to judge whether the AC power grid has a fault according to the voltage value of the first AC port of the flexible interconnection device before switching the flexible interconnection device for controlling the AC power grid to the current limiting mode when a fault in the AC power grid is detected; a third control unit, used to control the flexible interconnection device to operate in a power mode when no fault in the AC power grid occurs, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; and a second processing unit, used to execute the step of switching the flexible interconnection device for controlling the AC power grid to the current limiting mode when a fault in the AC power grid occurs.

[0103] Optionally, in the control device of the flexible interconnection device provided in the embodiment of the present application, the first judgment unit includes: a first acquisition subunit, used to acquire the voltage value of the last sampling of the voltage of the first AC port of the flexible interconnection device, and obtain the target voltage value of the first AC port; a second acquisition subunit, used to acquire the voltage value of the first AC port of the flexible interconnection device at the current moment, and obtain the current voltage value of the first AC port; a first processing subunit, used to calculate the difference between the current voltage value of the first AC port and the target voltage value of the first AC port, and determine whether the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than a second preset threshold; a first determination subunit, used to determine that a fault occurs in the AC power grid if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than the second preset threshold; and a second determination subunit, used to determine that no fault occurs in the AC power grid if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is not greater than the second preset threshold.

[0104] The control device of the flexible interconnection device includes a processor and a memory. The first processing unit 1001, the first control unit 1002 and the second control unit 1003 are all stored in the memory as program units, and the processor executes the program units stored in the memory to realize corresponding functions.

[0105] The processor includes a kernel, which calls the corresponding program unit from the memory. One or more kernels can be set, and the reliability of the flexible interconnection device can be improved by adjusting the kernel parameters.

[0106] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0107] An embodiment of the present invention provides a computer-readable storage medium on which a program is stored. When the program is executed by a processor, the control method of the flexible interconnection device is implemented.

[0108] An embodiment of the present invention provides a processor, which is used to run a program, wherein the control method of the flexible interconnection device is executed when the program is run.

[0109] like Fig.11 As shown, an embodiment of the present invention provides an electronic device, the device includes a processor, a memory, and a program stored in the memory and executable on the processor, and the processor implements the following steps when executing the program: when a fault in an AC power grid is detected, a flexible interconnection device for controlling the AC power grid is switched to a current limiting mode, and the flexible interconnection device is controlled to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than a preset current value; according to the voltage value of the first AC port of the flexible interconnection device within the first preset time, the first AC port of the flexible interconnection device is controlled to enter a temporary blocking state, and the first AC port of the flexible interconnection device is controlled to be in a temporary blocking state within a second preset time, wherein the first AC port is an AC port corresponding to the AC power grid; the residual voltage of the first AC port of the flexible interconnection device is detected within the second preset time, and the operation of the flexible interconnection device is controlled according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time.

[0110] When the processor executes the program, the following steps are also implemented: according to the voltage value of the first AC port of the flexible interconnection device within the first preset time length, controlling the first AC port of the flexible interconnection device to enter a temporarily locked state includes: judging whether the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within the first preset time length; if the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within the first preset time length, switching the flexible interconnection device to a power mode for operation, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; if the voltage value of the first AC port of the flexible interconnection device is not equal to the preset voltage value within the first preset time length, controlling the first AC port of the flexible interconnection device to enter a temporarily locked state.

[0111] When the processor executes the program, the following steps are also implemented: according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time length, controlling the operation of the flexible interconnection device includes: judging whether there is a residual voltage at the first AC port of the flexible interconnection device within the second preset time length; if there is a residual voltage at the first AC port of the flexible interconnection device within the second preset time length, controlling the first AC port of the flexible interconnection device to enter a permanent locked state, and controlling the second AC port of the flexible interconnection device to be in an operating state, wherein the second AC port is an AC port other than the first AC port in the flexible interconnection device; if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time length, switching the flexible interconnection device to a power transfer mode for operation, wherein the power transfer mode is used to control the second AC port of the flexible interconnection device to supply power to the first AC port of the flexible interconnection device.

[0112] When the processor executes the program, the following steps are also implemented: if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time length, the flexible interconnection device is switched to the power transfer mode for operation, including: if there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time length, it is determined whether there is an undervoltage module in the flexible interconnection device; if there is an undervoltage module in the flexible interconnection device, the undervoltage module in the flexible interconnection device is charged, and based on the charged undervoltage module, the flexible interconnection device is switched to the power transfer mode for operation; if there is no undervoltage module in the flexible interconnection device, the first AC port of the flexible interconnection device is unlocked, and the flexible interconnection device is switched to the power transfer mode for operation.

[0113] When the processor executes the program, the following steps are also implemented: based on the undervoltage module after charging, the flexible interconnection device is switched to the power transfer mode, including: judging whether the voltage value of the undervoltage module after charging is less than a first preset threshold value; if the voltage value of the undervoltage module after charging is less than the first preset threshold value, the undervoltage module in the flexible interconnection device continues to be charged; if the voltage value of the undervoltage module after charging is not less than the first preset threshold value, the first AC port of the flexible interconnection device is unlocked, and the flexible interconnection device is switched to the power transfer mode.

[0114] When the processor executes the program, the following steps are also implemented: when a fault in the AC power grid is detected, before the flexible interconnection device for controlling the AC power grid is switched to the current limiting mode for operation, the following steps are also included: judging whether the AC power grid has failed based on the voltage value of the first AC port of the flexible interconnection device; when the AC power grid has not failed, controlling the flexible interconnection device to operate in a power mode, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; when a fault in the AC power grid occurs, executing the step of switching the flexible interconnection device for controlling the AC power grid to the current limiting mode for operation.

[0115] When the processor executes the program, the following steps are also implemented: judging whether an AC power grid fails according to the voltage value of the first AC port of the flexible interconnection device includes: obtaining the voltage value of the last sampling of the voltage of the first AC port of the flexible interconnection device to obtain a target voltage value of the first AC port; obtaining the voltage value of the first AC port of the flexible interconnection device at the current moment to obtain a current voltage value of the first AC port; calculating the difference between the current voltage value of the first AC port and the target voltage value of the first AC port, and judging whether the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than a second preset threshold; if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than the second preset threshold, determining that an AC power grid fails; if the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is not greater than the second preset threshold, determining that no AC power grid fails.

[0116] The devices in this article can be servers, PCs, PADs, mobile phones, etc.

[0117] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program that is initialized with the following method steps: when a fault in an AC power grid is detected, a flexible interconnection device used to control the AC power grid is switched to a current limiting mode, and the flexible interconnection device is controlled to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than a preset current value; based on the voltage value of the first AC port of the flexible interconnection device within the first preset time, the first AC port of the flexible interconnection device is controlled to enter a temporarily locked state, and the first AC port of the flexible interconnection device is controlled to be in a temporarily locked state within a second preset time, wherein the first AC port is the AC port corresponding to the AC power grid; the residual voltage of the first AC port of the flexible interconnection device is detected within the second preset time, and the operation of the flexible interconnection device is controlled based on the residual voltage of the first AC port of the flexible interconnection device within the second preset time.

[0118] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0119] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0120] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0121] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0122] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0123] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0124] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0125] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0126] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0127] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A control method for a flexible interconnection device, characterized in that: include: When a fault in the AC power grid is detected, the flexible interconnection device used to control the AC power grid is switched to a current limiting mode, and the flexible interconnection device is controlled to operate in the current limiting mode for a first preset time, wherein the current limiting mode is used to limit the current value of the flexible interconnection device to not be greater than a preset current value; According to the voltage value of the first AC port of the flexible interconnection device within the first preset time period, the first AC port of the flexible interconnection device is controlled to enter a temporary blocking state, and the first AC port of the flexible interconnection device is controlled to be in a temporary blocking state within a second preset time period, wherein the first AC port is an AC port corresponding to the AC power grid; The residual voltage of the first AC port of the flexible interconnection device is detected within the second preset time period, and the operation of the flexible interconnection device is controlled according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time period.

2. The method according to claim 1, characterized in that According to the voltage value of the first AC port of the flexible interconnection device within the first preset time period, controlling the first AC port of the flexible interconnection device to enter a temporary locking state includes: Determining whether a voltage value of the first AC port of the flexible interconnection device is equal to a preset voltage value within the first preset time period; If the voltage value of the first AC port of the flexible interconnection device is equal to the preset voltage value within the first preset time period, the flexible interconnection device is switched to a power mode operation, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; If the voltage value of the first AC port of the flexible interconnect device is not equal to the preset voltage value within the first preset time period, the first AC port of the flexible interconnect device is controlled to enter a temporary locking state.

3. The method according to claim 1, characterized in that: Controlling the operation of the flexible interconnection device according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time period includes: Determining whether there is a residual voltage at the first AC port of the flexible interconnection device within the second preset time period; If there is a residual voltage at the first AC port of the flexible interconnection device within the second preset time period, the first AC port of the flexible interconnection device is controlled to enter a permanent locked state, and the second AC port of the flexible interconnection device is controlled to be in an operating state, wherein the second AC port is an AC port other than the first AC port in the flexible interconnection device; If there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time period, the flexible interconnection device is switched to a power transfer mode, wherein the power transfer mode is used to control the second AC port of the flexible interconnection device to supply power to the first AC port of the flexible interconnection device.

4. The method according to claim 3, characterized in that If there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time, switching the flexible interconnection device to the power transfer mode includes: If there is no residual voltage at the first AC port of the flexible interconnection device within the second preset time period, determining whether there is an undervoltage module in the flexible interconnection device; If there is an undervoltage module in the flexible interconnection device, the undervoltage module in the flexible interconnection device is charged, and based on the charged undervoltage module, the flexible interconnection device is switched to a power transfer mode; If the undervoltage module does not exist in the flexible interconnection device, the first AC port of the flexible interconnection device is unlocked, and the flexible interconnection device is switched to a power transfer mode.

5. The method according to claim 4, characterized in that Based on the charged undervoltage module, switching the flexible interconnection device to a power transfer mode includes: Determining whether the voltage value of the undervoltage module after charging is less than a first preset threshold; If the voltage value of the undervoltage module after charging is less than the first preset threshold, the undervoltage module in the flexible interconnection device continues to be charged; If the voltage value of the undervoltage module after charging is not less than the first preset threshold, the first AC port of the flexible interconnection device is unlocked, and the flexible interconnection device is switched to a power transfer mode.

6. The method according to claim 1, characterized in that When a fault in the AC power grid is detected, before the flexible interconnection device for controlling the AC power grid is switched to a current limiting mode, the method further includes: Determining whether a fault occurs in the AC power grid according to a voltage value of the first AC port of the flexible interconnection device; In the case that the AC power grid does not fail, controlling the flexible interconnection device to operate in a power mode, wherein the power mode is used to control the operation of the flexible interconnection device by adjusting the power of the AC port of the flexible interconnection device; In the event of a fault in the AC power grid, a step is performed of switching a flexible interconnection device for controlling the AC power grid to operate in a current limiting mode.

7. The method according to claim 6, characterized in that Judging whether the AC power grid fails according to the voltage value of the first AC port of the flexible interconnection device includes: Acquire a voltage value of a last sampled voltage of a first AC port of the flexible interconnection device to obtain a target voltage value of the first AC port; Acquire the voltage value of the first AC port of the flexible interconnection device at a current moment to obtain the current voltage value of the first AC port; Calculating a difference between a current voltage value of the first AC port and a target voltage value of the first AC port, and determining whether the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than a second preset threshold; If the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is greater than the second preset threshold, it is determined that the AC power grid fails; If the difference between the current voltage value of the first AC port and the target voltage value of the first AC port is not greater than the second preset threshold, it is determined that no fault occurs in the AC power grid.

8. A control device for a flexible interconnection device, characterized in that: include: a first processing unit, configured to switch a flexible interconnection device for controlling the AC power grid to operate in a current limiting mode when a fault in the AC power grid is detected, and control the flexible interconnection device to operate in the current limiting mode for a first preset time period, wherein the current limiting mode is configured to limit a current value of the flexible interconnection device to not be greater than a preset current value; a first control unit, configured to control the first AC port of the flexible interconnection device to enter a temporary blocking state according to a voltage value of the first AC port of the flexible interconnection device within the first preset time period, and control the first AC port of the flexible interconnection device to be in a temporary blocking state within a second preset time period, wherein the first AC port is an AC port corresponding to the AC power grid; The second control unit is used to detect the residual voltage of the first AC port of the flexible interconnection device within the second preset time period, and control the operation of the flexible interconnection device according to the residual voltage of the first AC port of the flexible interconnection device within the second preset time period.

9. A computer-readable storage medium, characterized in that: The storage medium stores a program, wherein the program executes the control method of the flexible interconnection device according to any one of claims 1 to 7.

10. An electronic device, characterized in that: It includes one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the control method of the flexible interconnection device according to any one of claims 1 to 7.

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