Flexible direct current converter valve

Abstract

The invention provides a flexible direct current converter valve. The flexible direct current converter valve comprises a valve control system and N cascaded submodules, wherein the valve control system communicates with the N submodules; each sub-module comprises a bypass switch and a sub-module control unit; the bypass switch comprises a trigger unit and a switch position detection unit, each sub-module further comprises an optical position detection unit, and each optical position detection unit comprises an input optical fiber and an output optical fiber which are respectively connected with the sub-module control units of the adjacent sub-modules; the structure base is used for installing an input optical fiber and an output optical fiber; the position baffle plate is connected with the bypass switch, and when the bypass switch is in a closing state or an opening state, the positions of the position baffle plate are different: when the bypass switch is in the closing state, the position baffle plate is in a first position, and the output optical fiber receives a signal transmitted by the input optical fiber; and when the bypass switch is in an opening state, the position baffle is in a second position, and the output optical fiber does not receive the signal transmitted by the input optical fiber.

Description

Technical Field

[0001] The present application relates to the technical field of flexible direct current transmission, and in particular to a flexible direct current converter valve. Background Art

[0002] The converter valve is a key device for realizing AC-DC power conversion. The flexible DC converter valve is a power type converter valve, which mostly adopts a modular multi-level topology. The modular multi-level converter valve is composed of several sub-modules with exactly the same structure connected in series. The converter valve sub-module is composed of fully controlled power devices (such as IGBT), DC capacitors, bypass switches, sub-module control units, drive boards, power modules and other components. The voltage output by the sub-module is controlled by controlling the opening and closing of the power devices in the converter valve sub-module.

[0003] The bypass switch is a key component of the flexible direct current converter valve, which is used to bypass the faulty submodule in operation. After the faulty submodule is bypassed, the non-faulty submodule can continue to operate. The bypass switch of the submodule can ensure the overall stable operation of the converter valve equipment. The bypass switch status is the key status information of the submodule. After the bypass switch is closed, its status information is fed back to the upper control and protection system through the submodule control unit. After a submodule fails, if the control unit sends a bypass command and does not receive the submodule bypass status information, the system will not be able to determine whether the faulty submodule has been bypassed correctly. If the submodule fails to bypass normally, it may cause overvoltage breakdown of the submodule, thereby affecting the safe operation of the equipment. Therefore, in engineering, the bypass switch status information is usually associated with the fault judgment of switch refusal, and switch refusal may cause the converter valve to trip and stop operating.

[0004] The status of the bypass switch cannot be monitored or cannot reflect the actual status of the bypass, which will affect the operation. There have been many cases in flexible direct current projects where the bypass switch caused the system to shut down or trip.

[0005] The above information disclosed in the Background section is only for enhancement of understanding of the background of the present application and therefore it may contain information that does not constitute the prior art that is already known to a person of ordinary skill in the art. Summary of the invention

[0006] In order to solve at least one of the above problems, the present application proposes a flexible direct current valve.

[0007] According to the first aspect of the present application, at least one embodiment of the present application provides a flexible direct current converter valve, the flexible direct current converter valve comprising a valve control system and N cascaded submodules, N being an integer greater than or equal to 2, the valve control system being respectively connected to the N submodules via a first optical fiber for communication; each of the N submodules comprising a bypass switch and a submodule control unit; the bypass switch comprising a trigger unit and at least one switch position detection unit, wherein: each of the N submodules further comprising an optical position detection unit, the optical position detection unit comprising: at least one input optical fiber and at least one output optical fibers, respectively connected to submodule control units of adjacent submodules; a structural base, used to install the input optical fiber and the output optical fiber; a position baffle, connected to the bypass switch, and when the bypass switch is in a closed state or an open state, the position of the position baffle is different, wherein: when the bypass switch is in the closed state, the position baffle is in a first position, and the output optical fiber receives the signal transmitted by the input optical fiber; when the bypass switch is in the open state, the position baffle is in a second position, and the output optical fiber does not receive the signal transmitted by the input optical fiber.

[0008] For example, in some embodiments of the present application, the trigger unit is connected to the sub-module control unit via a second optical fiber to receive a control signal of the valve control system forwarded by the sub-module control unit; and is connected to the sub-module control unit of the adjacent sub-module via a third optical fiber to receive a control signal of the valve control system forwarded by the sub-module control unit of the adjacent sub-module.

[0009] For example, in some embodiments of the present application, the position baffle includes a structural member with a pore, wherein: when the position baffle is in the first position, the pore is aligned with the input optical fiber, and the output optical fiber receives the signal transmitted by the input optical fiber; when the position baffle is in the second position, the pore is not aligned with the input optical fiber, and the output optical fiber cannot receive the signal transmitted by the input optical fiber.

[0010] For example, in some embodiments of the present application, the switch position detection unit includes a position relay, wherein: the position relay is linked with the transmission mechanism of the bypass switch, wherein: when the bypass switch is in a closed state, the position relay outputs a first node signal; when the bypass switch is in an open state, the position relay outputs a second node signal; the position relay is connected to the sub-module control unit, and the sub-module control unit determines the state of the bypass switch according to the node signal output by the position relay.

[0011] For example, in some embodiments of the present application, the switch position detection unit includes at least two groups of position relays, wherein: when the bypass switch is in a closed state, each group of the two groups of position relays outputs a first node signal; when the bypass switch is in an open state, each group of the two groups of position relays outputs a second node signal.

[0012] For example, in some embodiments of the present application, when one group of position relays in the two groups of position relays outputs a first node signal and the other group of position relays outputs a second node signal, the submodule control unit determines that the bypass switch is in a closed state.

[0013] For example, in some embodiments of the present application, the sub-module control unit is used to determine the state of the bypass switch according to the node signal output by the switch position detection unit, and upload the state of the bypass switch to the valve control system; the sub-module control unit is also used to receive the control signal of the valve control system to control the trigger unit of the bypass switch so that the bypass switch is closed or opened.

[0014] For example, in some embodiments of the present application, the submodule control unit of the adjacent submodule is connected to the valve control system via the first optical fiber; the submodule control unit of the adjacent submodule determines the bypass switch state of the submodule based on the signal transmitted by the output optical fiber, and uploads the bypass switch state of the submodule to the valve control system via the first optical fiber.

[0015] For example, in some embodiments of the present application, the submodule control unit of the adjacent submodule is also used to receive the control signal of the valve control system, and control the trigger unit of the bypass switch of the submodule through the third optical fiber to close or open the bypass switch.

[0016] For example, in some embodiments of the present application, the flexible DC converter valve includes at least three sub-modules; each of the optical position detection units includes at least two input optical fibers and at least two output optical fibers, wherein: the at least two input optical fibers are respectively connected to the sub-module control units of two adjacent sub-modules; the at least two output optical fibers are respectively connected to the sub-module control units of two adjacent sub-modules.

[0017] For example, in some embodiments of the present application, the optical position detection unit includes a first input optical fiber, a second input optical fiber, a first output optical fiber and a second output optical fiber, wherein: the first input optical fiber, the second input optical fiber, the first output optical fiber and the second output optical fiber are installed on the structural base.

[0018] For example, in some embodiments of the present application, each of the N submodules further includes a semiconductor switch unit, wherein: the semiconductor switch unit is connected to the bypass switch; and the semiconductor switch unit is a half-bridge structure or a full-bridge structure.

[0019] The flexible direct current converter valve provided by the present application can realize redundant detection of the bypass state of the flexible direct current converter valve, improve the reliability of the bypass detection of the converter valve, and provide guarantee for the startup and stable operation of the converter valve. The flexible direct current converter valve provided by the present application also has at least one of the following advantages:

[0020] (1) The flexible DC converter valve is equipped with both a local switch position detection unit of the submodule and an optical position detection unit based on optical detection, and has redundant bypass status detection capability.

[0021] (2) The position detection of the flexible DC converter valve submodule does not completely rely on the detection of the submodule control unit configured in the submodule. In the event of an abnormality in the submodule control unit, the submodule bypass state is obtained through the optical position detection unit configured in the submodule and the control unit of the adjacent submodule.

[0022] (3) The optical position detection unit based on optical detection is connected to the submodule control unit of the adjacent submodule in the converter valve through an optical fiber. Its position detection does not depend on the power supply of the submodule itself, so that the flexible DC converter valve can detect the position status of its bypass switch through the adjacent submodule when the submodule power supply fails, the startup is abnormal, or the communication fails.

[0023] (4) When the optical position detection unit communicates abnormally with the adjacent submodule, the flexible direct current valve can also communicate with the adjacent submodule control unit through the submodule control unit to report the bypass status of the submodule to the valve control system.

[0024] (5) The trigger unit of the bypass switch of the flexible DC converter valve submodule includes two input controls, one of which is the optical fiber input from the submodule control unit of the adjacent submodule, so that the flexible DC converter valve can also trigger the bypass switch of the submodule in the event of a submodule failure.

[0025] It should be understood that the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] By describing in detail exemplary embodiments thereof with reference to the accompanying drawings, the above and other objects, features and advantages of the present application will become more apparent. The accompanying drawings described below are only some embodiments of the present application, and are not intended to limit the present application.

[0027] Figure 1 A schematic diagram of a flexible direct current converter valve for redundantly detecting a bypass state according to an exemplary embodiment is shown;

[0028] Figure 2 A submodule schematic diagram of an exemplary embodiment is shown;

[0029] Figure 3 A schematic diagram of an optical position detection unit showing an exemplary embodiment;

[0030] Figure 4 A schematic diagram of a semiconductor switch unit showing an exemplary embodiment;

[0031] Figure 5 Another embodiment of an exemplary semiconductor switch unit is shown;

[0032] Figure 6 A further embodiment of an exemplary optical position detection unit is shown;

[0033] Figure 7 Schematic diagram of a dual-circuit optical position detection unit used in a flexible direct current valve. DETAILED DESCRIPTION

[0034] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this application will be comprehensive and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted.

[0035] The described features, structures or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of these specific details, or other modes, components, materials, devices, etc. may be adopted. In these cases, known structures, methods, devices, implementations, materials or operations will not be shown or described in detail.

[0036] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the contents and operations or steps, nor do they have to be executed in the order described. For example, some operations or steps can be decomposed, and some operations or steps can be combined or partially combined, so the actual execution order may change according to actual conditions.

[0037] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices.

[0038] Those skilled in the art will appreciate that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present application, and therefore cannot be used to limit the scope of protection of the present application.

[0039] Figure 1 A schematic diagram of a flexible DC converter valve for redundantly detecting a bypass state according to an exemplary embodiment is shown.

[0040] like Figure 1 As shown, the flexible direct current converter valve includes a valve control system 101 and N cascaded submodules 1021...102N, where N is an integer greater than or equal to 2. The valve control system 101 is connected to the N submodules through a first optical fiber for communication. Each of the N submodules includes a semiconductor switch unit 102N1, a DC energy storage element, a bypass switch, a submodule control unit and an IGBT driver board.

[0041] like Figure 2 As shown, taking the submodule 102N as an example, the submodule 102N includes a semiconductor switch unit 102N1, a DC energy storage element 102N2, a bypass switch 102N3, a submodule control unit 102N4, an IGBT driving board 102N5 and an optical position detection unit 102N6.

[0042] According to an exemplary embodiment, the optical position detection unit 102N6 includes at least one input optical fiber SWR2 and at least one output optical fiber SWT2. The input optical fiber SWR2 and the output optical fiber SWT2 are respectively connected to the sub-module control units of the adjacent sub-modules.

[0043] For example, when the flexible direct current converter valve includes two submodules, one input optical fiber and one output optical fiber of the optical position detection unit of submodule n are connected to the submodule control unit of the adjacent submodule n+1. One input optical fiber and one output optical fiber of the optical position detection unit of submodule n+1 are connected to the submodule control unit of the adjacent submodule n.

[0044] like Figure 3 As shown, the optical position detection unit 102N6 includes a structural base 102N62 and a position stopper 102N61.

[0045] The structural base 102N62 is used to install the input optical fiber SWR2 and the output optical fiber SWT2.

[0046] According to some embodiments, the input optical fiber SWR2 and the output optical fiber SWT2 are coaxially arranged. The position baffle 102N61 is linked with the transmission mechanism of the bypass switch. When the bypass switch is in the open state or the closed state, the position baffle will produce a displacement change.

[0047] The position baffle 102N61 is connected to the bypass switch. When the bypass switch is in the closed state or the open state, the position of the position baffle is different: when the bypass switch is in the closed state, the position baffle is in the first position, and the output optical fiber receives the signal transmitted by the input optical fiber; when the bypass switch is in the open state, the position baffle is in the second position, and the output optical fiber does not receive the signal transmitted by the input optical fiber. The submodule control unit of the adjacent submodule determines whether the bypass switch is in the open state or the closed state according to whether the output optical fiber SWT2 receives the input optical fiber SWR2 signal.

[0048] According to some embodiments, Figure 3 As shown, the position baffle 102N61 is a structural member with a hole. When the position baffle is in the first position, the hole of the position baffle is aligned with the input optical fiber, that is, when the hole of the position baffle is aligned with the input optical fiber of the optical position detection unit, the output optical fiber can receive the signal transmitted by the input optical fiber. When the position baffle is in the second position, the hole of the position baffle is not aligned with the input optical fiber, that is, when the main contact of the bypass switch is actuated, the hole of the position baffle is displaced relative to the input optical fiber, and the output optical fiber cannot receive the signal transmitted by the input optical fiber.

[0049] This application takes the position baffle with pores as an example. The use of pore design can simplify the structural design of the position baffle of the optical position detection unit, and facilitate the coordination of the optical fiber and the position baffle. In addition, the optical position detection unit based on optical detection in submodule n is connected to the submodule control unit of the adjacent submodule n+1 through the input optical fiber and the output optical fiber. This optical fiber detection method does not rely on the power supply and energy extraction of submodule n. This detection method can detect the position state of the bypass switch of submodule n through the adjacent submodule n+1 when the power supply of the converter valve submodule n fails, the startup is abnormal, or the control unit of submodule n fails.

[0050] According to some embodiments, the optical position detection unit may be disposed inside the bypass switch.

[0051] According to an exemplary embodiment, the submodule control unit is connected to the valve control system via a first optical fiber TR1. The bypass switch 102N3 includes a trigger unit and at least one switch position detection unit. Figure 2As shown, the trigger unit is connected to two optical fibers: the second optical fiber SR1 and the third optical fiber SR2. The trigger unit is connected to the submodule control unit through the second optical fiber SR1 to receive the control signal of the valve control system forwarded by the submodule control unit. The trigger unit is connected to the submodule control unit of the adjacent submodule through the third optical fiber SR2 to receive the control signal of the valve control system forwarded by the submodule control unit of the adjacent submodule.

[0052] According to an example embodiment, the switch position detection unit includes a position relay. The position relay is linked to the transmission mechanism of the bypass switch. When the bypass switch is in an open state or a closed state, the node signal output by the position relay changes: when the bypass switch is in a closed state, the position relay outputs a first node signal; when the bypass switch is in an open state, the position relay outputs a second node signal. The submodule control unit is connected to the position relay. The submodule control unit determines the state of the bypass switch according to the node signal output by the position relay.

[0053] For example, Figure 2 As shown, the switch position detection unit includes two sets of position relays: a first relay S1 and a second relay S2. When the bypass switch is in the closed state, the two sets of position relays output a first node signal, indicating that the bypass switch is in the closed state. When the bypass switch is in the open state, the two sets of position relays output a second node signal, indicating that the bypass switch is in the open state.

[0054] According to some embodiments, when one group of position relays in the two groups of position relays outputs a first node signal and the other group of position relays outputs a second node signal, the submodule control unit determines that the bypass switch is in a closed state.

[0055] The submodule control unit is used to determine the state of the bypass switch according to the node signal output by the switch position detection unit, and upload the state of the bypass switch to the valve control system. The submodule control unit is also used to receive the control signal of the valve control system and forward it to the trigger unit to control the trigger unit of the bypass switch to trigger the bypass switch to close or open.

[0056] The trigger unit of the bypass switch of the flexible DC converter valve submodule includes two input controls, one of which is the optical fiber input from the submodule control unit of the adjacent submodule. This allows the flexible DC converter valve to trigger the bypass switch of the submodule through the submodule control unit of the adjacent submodule in the event of a submodule failure.

[0057] According to an example embodiment, Figure 1As shown, the submodule control unit of the adjacent submodule is connected to the valve control system through the first optical fiber. The submodule control unit of the adjacent submodule determines the bypass switch state of the submodule according to the signal transmitted by the output optical fiber, and uploads the bypass switch state of the submodule to the valve control system through the first optical fiber.

[0058] According to some embodiments, the submodule control unit of the adjacent submodule n+1 of submodule n can be connected to the trigger unit of the bypass switch of submodule n through a third optical fiber, and the submodule control unit of submodule n+1 can send a control signal to the trigger unit to trigger the closing or opening of the bypass switch of submodule n. The submodule control unit of submodule n can be connected to the trigger unit of the bypass switch of submodule n+1 through a third optical fiber, and the control unit of submodule n can send a control signal to the trigger unit to trigger the closing or opening of the bypass switch of submodule n+1.

[0059] For example, when the flexible direct current valve includes two submodules, when submodule n fails, the submodule control unit of the adjacent submodule n+1 determines the bypass switch state of submodule n according to the signal transmitted by the output optical fiber, and uploads it to the valve control system. After receiving the control signal of the valve control system, the submodule control unit of submodule n triggers the trigger unit of submodule n through the second optical fiber to control the bypass switch of submodule n to close or open.

[0060] For another example, when the flexible direct current converter valve includes two submodules, when submodule n fails, the submodule control unit of the adjacent submodule n+1 determines the bypass switch state of submodule n according to the signal transmitted by the output optical fiber, and uploads it to the valve control system. After the submodule control unit of the adjacent submodule n+1 receives the control signal of the valve control system through the first optical fiber, it triggers the trigger unit of submodule n through the third optical fiber to control the bypass switch of submodule n to close or open.

[0061] In the present application, the submodule position detection of the flexible direct current converter valve does not completely rely on the submodule control unit configured by the submodule for detection. In the case of an abnormality in the submodule control unit, the bypass state of the submodule can also be obtained through the optical position detection unit configured by the submodule and the submodule control unit of the adjacent submodule. In addition, the bypass switch state of submodule n can also be reported to the valve control system through submodule n+1 to achieve redundant detection and control of the bypass switch of submodule n, which does not rely solely on submodule n, so that the flexible direct current converter valve has higher operational reliability.

[0062] According to some embodiments, the semiconductor switch unit 102N1 is connected to the bypass switch. The semiconductor switch unit 102N1 is a half-bridge structure or a full-bridge structure.

[0063] Figure 4The semiconductor switch unit is a schematic diagram of a half-bridge structure, wherein the semiconductor switch unit includes a first turn-off semiconductor T1, a first freewheeling diode D1 anti-parallel to the first turn-off semiconductor T1, a second turn-off semiconductor T2, and a second freewheeling diode D2 anti-parallel to the second turn-off semiconductor T2. The first turn-off semiconductor T1 and the second turn-off semiconductor T2 are connected in series in the same direction.

[0064] Figure 5 The semiconductor switch unit is a schematic diagram of a full-bridge structure, and the semiconductor switch unit includes a first turn-off semiconductor T1, a second turn-off semiconductor T2, a third turn-off semiconductor T3, and a fourth turn-off semiconductor T4. Among them, the first turn-off semiconductor T1 and the second turn-off semiconductor T2 are connected in series in the same direction, and the third turn-off semiconductor T3 and the fourth turn-off semiconductor T4 are connected in series in the same direction, and the above two series branches are connected in parallel. The first turn-off semiconductor T1, the second turn-off semiconductor T2, the third turn-off semiconductor T3, and the fourth turn-off semiconductor T4 are respectively connected with the first freewheeling diode D1, the second freewheeling diode D2, the third freewheeling diode D3, and the fourth freewheeling diode D4 in anti-parallel connection. The connection point between the first turn-off semiconductor T1 and the third turn-off semiconductor T3 is the positive terminal X1 of the semiconductor switch unit, and the connection point between the second turn-off semiconductor T2 and the fourth turn-off semiconductor T4 is the negative terminal X1 of the semiconductor switch unit. The output terminal M1 is connected to the connection point between the first turn-off semiconductor T1 and the second turn-off semiconductor T2. The output terminal M2 is connected to the connection point between the third turn-off semiconductor T3 and the fourth turn-off semiconductor T4.

[0065] The present application takes a flexible direct current converter valve including more than three cascaded submodules as an example: one input optical fiber and one output optical fiber of the optical position detection unit of submodule n are connected to the submodule control unit of the adjacent submodule n+1. One input optical fiber and one output optical fiber of the optical position detection unit of submodule n+1 are connected to the submodule control unit of the adjacent submodule n-1. One input optical fiber and one output optical fiber of the optical position detection unit of submodule n-1 are connected to the submodule control unit of the adjacent submodule n.

[0066] The trigger unit of the bypass switch of submodule n includes two input controls: one is the second optical fiber input from the submodule control unit of submodule n, and the other is the third optical fiber input from the control unit of the adjacent submodule n+1. The submodule control unit of submodule n can send a control signal to trigger the bypass switch of submodule n to close or open. The control unit of submodule n+1 can also send a control signal to trigger the bypass switch of submodule n to close or open.

[0067] Similarly, the control unit of submodule n is connected to the trigger unit of the bypass switch of submodule n-1 through a third optical fiber, and the control unit of submodule n can send a control signal to trigger the bypass switch of submodule n-1 to close or open.

[0068] The present application provides a flexible DC converter valve for redundantly detecting bypass status. The flexible DC converter valve is configured with both a local switch position detection unit of a submodule and an optical position detection unit based on optical detection. The flexible DC converter valve can realize redundant detection of the bypass status of the flexible DC converter valve, improve the reliability of the converter valve bypass detection, and provide guarantee for the startup and stable operation of the flexible DC converter valve.

[0069] According to some embodiments, Figure 2 As shown, the submodule control unit of submodule n also includes a pair of communication optical fibers TR2, which are used to connect to the submodule control unit of the adjacent submodule n+1. The bypass switch state of submodule n can be transmitted to submodule n+1 via the communication optical fiber, and the bypass switch state of submodule n+1 can be transmitted to submodule n via the communication optical fiber.

[0070] The flexible direct current switching valve can also communicate with the adjacent submodule control unit through the submodule control unit when the optical position detection unit communicates abnormally with the adjacent submodule. The submodule control unit sends information on the bypass switch status to the submodule control unit of the adjacent submodule, and the submodule control unit of the adjacent submodule reports the status of the bypass switch of the submodule to the valve control system.

[0071] Figure 6 A further embodiment of an exemplary optical position detection unit is shown.

[0072] like Figure 6 As shown, the optical position detection unit includes at least two input optical fibers and at least two output optical fibers, and is a dual-loop optical position detection unit. The at least two input optical fibers are respectively connected to the submodule control units of two adjacent submodules n+1 and n-1. The at least two output optical fibers are respectively connected to the submodule control units of two adjacent submodules n+1 and n-1.

[0073] For example, the optical position detection unit includes a first input optical fiber, a second input optical fiber, a first output optical fiber, and a second output optical fiber. The first input optical fiber and the first output optical fiber of the optical position detection unit of submodule n are connected to the submodule control unit of the adjacent submodule n+1; the second input optical fiber and the second output optical fiber of the optical position detection unit of submodule n are connected to the submodule control unit of the adjacent submodule n-1.

[0074] The first input optical fiber, the second input optical fiber, the first output optical fiber, and the second output optical fiber are installed on the structural base, using a position baffle. The first input optical fiber is coaxially arranged with the first output optical fiber, and the second input optical fiber is coaxially arranged with the second output optical fiber. When the bypass switch is in the open state or the closed state, the position baffle will produce displacement changes.

[0075] The position baffle is connected to the bypass switch. When the bypass switch is in the closed state or the open state, the position of the position baffle is different: when the bypass switch is in the closed state, the position baffle is in the first position, the first output optical fiber receives the signal transmitted by the first input optical fiber, and the second output optical fiber receives the signal transmitted by the second input optical fiber; when the bypass switch is in the open state, the position baffle is in the second position, the first output optical fiber does not receive the signal transmitted by the first input optical fiber, and the second output optical fiber does not receive the signal transmitted by the second input optical fiber. The submodule control unit of the adjacent submodule determines whether the bypass switch is in the open state or the closed state according to whether the first output optical fiber and the second output optical fiber receive the signals of the first input optical fiber and the second input optical fiber.

[0076] According to some embodiments, Figure 6 As shown, the position baffle is a structural member with a hole. When the position baffle is in the first position, the hole of the position baffle is aligned with the first input optical fiber and the second input optical fiber, that is, when the hole of the position baffle is aligned with the first input optical fiber and the second input optical fiber of the optical position detection unit, the first output optical fiber and the second output optical fiber can receive the signal transmitted by the first input optical fiber and the second input optical fiber. When the position baffle is in the second position, the hole of the position baffle is not aligned with the first input optical fiber and the second input optical fiber, that is, when the main contact of the bypass switch is actuated, the hole of the position baffle is displaced relative to the first input optical fiber and the second input optical fiber, and the first output optical fiber and the second output optical fiber cannot receive the signal transmitted by the input optical fiber.

[0077] Figure 7 Schematic diagram of a dual-circuit optical position detection unit used in a flexible direct current valve. Figure 7 The structure of the flexible direct current valve is shown in Figure 1 The structures of the flexible direct current valves shown are basically the same, the only difference is that: Figure 7 The optical position detection unit in the flexible direct current converter valve shown includes two input optical fibers and two output optical fibers. For example, the first input optical fiber and the first output optical fiber of the optical position detection unit of submodule n are connected to the submodule control unit of submodule n-1. The second input optical fiber and the second output optical fiber of the optical position detection unit of submodule n are connected to the submodule control unit of submodule n+1.

[0078] The present application adds a detection optical fiber to the position baffle, so that the submodules connected on both sides of the submodule can detect the position of the bypass switch of the submodule, increasing the redundant detection capability of the bypass switch position status, thereby further improving the reliability of the operation of the flexible direct current converter valve.

[0079] It should be clearly understood that the present application describes how to form and use specific examples, but the present application is not limited to any details of these examples. On the contrary, based on the teaching of the content disclosed in the present application, these principles can be applied to many other embodiments.

[0080] In addition, it should be noted that the above figures are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, and are not intended to be limiting. It is easy to understand that the processes shown in the above figures do not indicate or limit the time sequence of these processes. In addition, it is also easy to understand that these processes can be performed synchronously or asynchronously, for example, in multiple modules.

[0081] The exemplary embodiments of the present application are specifically shown and described above. It should be understood that the present application is not limited to the detailed structures, configurations or implementations described herein; on the contrary, the present application is intended to cover various modifications and equivalent configurations included in the spirit and scope of the appended claims.

Claims

1. A flexible direct current valve, characterized in that: The flexible direct current converter valve comprises a valve control system and N cascaded submodules, where N is an integer greater than or equal to 2, and the valve control system is respectively connected to the N submodules through a first optical fiber for communication; each of the N submodules comprises a bypass switch and a submodule control unit; the bypass switch comprises a trigger unit and at least one switch position detection unit, wherein: Each of the N submodules further includes an optical position detection unit, and the optical position detection unit includes: At least one input optical fiber and at least one output optical fiber are respectively connected to the submodule control units of adjacent submodules; A structural base, used for mounting the input optical fiber and the output optical fiber; A position baffle is connected to the bypass switch, and when the bypass switch is in a closed state or an open state, the position of the position baffle is different, wherein: When the bypass switch is in a closed state, the position baffle is in a first position, and the output optical fiber receives a signal transmitted by the input optical fiber; When the bypass switch is in the open state, the position baffle is in the second position, and the output optical fiber does not receive the signal transmitted by the input optical fiber.

2. The flexible direct current valve according to claim 1, characterized in that: The trigger unit is connected to the submodule control unit via a second optical fiber to receive a control signal of the valve control system forwarded by the submodule control unit; and is connected to the submodule control unit of the adjacent submodule via a third optical fiber to receive a control signal of the valve control system forwarded by the submodule control unit of the adjacent submodule.

3. The flexible direct current valve according to claim 1, characterized in that: The position baffle comprises a structural member with a hole, wherein: When the position baffle is in the first position, the aperture is aligned with the input optical fiber, and the output optical fiber receives the signal transmitted by the input optical fiber; When the position stopper is in the second position, the aperture is not aligned with the input optical fiber, and the output optical fiber cannot receive the signal transmitted by the input optical fiber.

4. The flexible direct current valve according to claim 1, characterized in that: The switch position detection unit comprises a position relay, wherein: The position relay is linked to the transmission mechanism of the bypass switch, wherein: When the bypass switch is in a closed state, the position relay outputs a first node signal; When the bypass switch is in an open state, the position relay outputs a second node signal; The position relay is connected to the submodule control unit, and the submodule control unit determines the state of the bypass switch according to the node signal output by the position relay.

5. The flexible direct current valve according to claim 4, characterized in that: The switch position detection unit includes at least two groups of position relays, wherein: When the bypass switch is in a closed state, a first node signal of each group of position relays in the two groups of position relays; When the bypass switch is in an open state, each group of position relays in the two groups of position relays outputs a second node signal.

6. The flexible direct current valve according to claim 5, characterized in that: In the case where one group of position relays in the two groups of position relays outputs a first node signal and the other group of position relays outputs a second node signal, the submodule control unit determines that the bypass switch is in a closed state.

7. The flexible direct current valve according to claim 2, characterized in that: The submodule control unit is used to determine the state of the bypass switch according to the node signal output by the switch position detection unit, and upload the state of the bypass switch to the valve control system; The submodule control unit is further used to receive a control signal from the valve control system to control a trigger unit of the bypass switch so that the bypass switch is closed or opened.

8. The flexible direct current valve according to claim 7, characterized in that: The submodule control unit of the adjacent submodule is connected to the valve control system via the first optical fiber; The submodule control unit of the adjacent submodule determines the bypass switch state of the submodule according to the signal transmitted by the output optical fiber, and uploads the bypass switch state of the submodule to the valve control system through the first optical fiber.

9. The flexible direct current valve according to claim 8, characterized in that: The submodule control unit of the adjacent submodule is further used to receive a control signal from the valve control system, and control a trigger unit of a bypass switch of the submodule through the third optical fiber to close or open the bypass switch.

10. The flexible direct current valve according to claim 1, characterized in that: The flexible direct current converter valve comprises at least three submodules; Each of the optical position detection units comprises at least two input optical fibers and at least two output optical fibers, wherein: The at least two input optical fibers are respectively connected to the submodule control units of two adjacent submodules; The at least two output optical fibers are respectively connected to the submodule control units of two adjacent submodules.

11. The flexible direct current valve according to claim 10, characterized in that: The optical position detection unit comprises a first input optical fiber, a second input optical fiber, a first output optical fiber and a second output optical fiber, wherein: The first input optical fiber, the second input optical fiber, the first output optical fiber, and the second output optical fiber are installed on the structural base.

12. The flexible direct current valve according to claim 1, characterized in that: Each of the N submodules further includes a semiconductor switch unit, wherein: The semiconductor switch unit is connected to the bypass switch; The semiconductor switch unit is a half-bridge structure or a full-bridge structure.

Images