Modular batch energy harvesting commutation circuit and control method

Abstract

The modularized batch energy acquisition commutation circuit includes a batch energy acquisition unit and N submodules, where AC terminals of the N submodules are connected in series (N is an integer greater than or equal to 2), and the submodules include a power unit (1) including a power semiconductor device and having an AC terminal drawn out to serve as the AC terminal of the submodule, and a capacitance unit (2) connected in parallel with the power unit (1), and the batch energy acquisition unit includes a first energy acquisition power source (6) whose negative terminal is connected to the negative terminal of the capacitance unit (2) of the first submodule of the N submodules or connected via a current limiting unit, and a connection network (30) whose input terminal is connected directly to the positive terminal of the first energy acquisition power source (6) or connected via a current limiting unit, and whose N output terminals are connected to the positive terminals of the capacitance units (2), respectively, or connected via current limiting units.

Description

[Technical field]

[0001] The present application relates to the technical field of high power electronic commutation, and in particular to a modular batch energy harvesting commutation circuit and control method. [Background technology]

[0002] With the application and development of power electronic technology in power systems, power electronic equipment has developed toward high-voltage, large-capacity modularization, and has been widely applied in fields such as flexible direct current transmission systems and chain static var generators. Here, the flexible direct current transmission system is generally composed of several sub-modules connected in series or parallel.

[0003] After the submodules are transported to the site and assembled into the valve tower, functional tests of the submodules and the entire diversion circuit need to be carried out again to ensure the equipment is in good working order due to possible malfunctions that may have occurred during transportation and installation.

[0004] Take a high-voltage, large-capacity flexible DC power transmission system as an example. One bridge arm contains hundreds of sub-modules. The conventional test scheme requires applying test power to each sub-module individually and performing function tests one by one. The main problems are as follows: (1) The number of sub-modules is large, the test workload is large, the test time is long, the test is difficult, and the operation after the sub-modules are configured into the valve tower is difficult. (2) During the test, the optical fiber needs to be plugged in and out. The process of plugging in and out the optical fiber carries the risk of damaging the optical fiber interface and the optical fiber itself. Frequent plugging and unplugging will also affect the service life and have an adverse effect on the reliability of the equipment. (3) When the submodule control unit program needs to be replaced during testing or inspection and maintenance, the amount of work required to use a single power-on method is large, and manual operation is prone to problems.

[0005] Meanwhile, the existing test schemes can only perform separate system tests such as sub-module function tests or insulation tests, and lack a high-voltage, high-power operational test scheme for the entire commutation circuit, resulting in incomplete test items and low test efficiency.

[0006] On the other hand, in the early stage of installation and adjustment, there may be many faulty submodules in the batch submodule. When adopting automatic testing, each of the submodules connected in series must establish communication with the valve control device, and the submodule control unit, drive, and power device must be normal and output the zero voltage level state. Once a faulty submodule occurs in the middle, the test must be interrupted, requiring a long time of discharge and inspection, which will affect the test efficiency. After the test is completed, the submodule bypass switch must be manually opened, which may cause the opening switch to be insufficient.

[0007] Take the offshore wind power flexible DC system as an example. The grid connection of offshore wind power is an important application of flexible DC transmission, and the flexible DC offshore commutation station needs to be built on an offshore platform. Considering the limitations of offshore construction conditions, the installation and testing of large equipment cannot be completed offshore, and the equipment needs to be installed and adjusted at the wharf before the entire offshore platform is sent to the designated sea area. If the offshore flexible DC commutation station arrives at the designated sea area and finds any quality defects or other problems with the large equipment, the entire platform needs to be transported to the testing wharf for processing, which is very expensive and time-consuming.

[0008] Therefore, for the above-mentioned usage scenarios, it is extremely important to conduct equipment testing at the wharf. However, wharves can usually only provide a small amount of low-voltage power, and existing testing techniques require testing the commutation circuit using high voltage. Summary of the Invention [Problem to be solved by the invention]

[0009] To solve the above problems, the present application provides a modular batch energy harvesting commutation circuit and control method. [Means for solving the problem]

[0010] The information disclosed in the above background art is only used to enhance understanding of the background of the present application, and therefore may contain information that does not constitute prior art known to those skilled in the art.

[0011] According to one aspect of the present application, there is provided a modularized batch energy harvesting commutation circuit, comprising a batch energy harvesting unit and N submodules, AC terminals of the N submodules are connected in series, and N is an integer equal to or greater than 2. The submodules include a power unit including a power semiconductor device and having an AC terminal drawn out to serve as the AC terminal of the submodule, and a capacitance unit connected in parallel with the power unit, and the batch energy harvesting unit includes a first energy harvesting power source having a negative terminal connected to a negative terminal of a capacitance unit of a first submodule of the N submodules or connected via a current limiting unit, and a connection network having an input terminal directly connected to a positive terminal of the first energy harvesting power source or connected via a current limiting unit, and N output terminals connected to the positive terminals of the capacitance units or connected via current limiting units, respectively.

[0012] According to some embodiments, the sub-module power units in the commutation circuit are all half-bridge circuits, or all full-bridge circuits, or a mixed arrangement of full-bridge circuits and half-bridge circuits, the half-bridge circuit includes an upper tube and a lower tube, the upper tube is connected in series with the lower tube and then connected in parallel with the capacitance unit, the collector and emitter of the upper tube or the lower tube are pulled out to become the AC terminal of the sub-module, the full-bridge circuit includes two upper tubes and two lower tubes, the upper tube is connected in series with the lower tube to form a bridge arm and then connected in parallel with the capacitance unit, the midpoint of the bridge arm is pulled out to become the AC output terminal of the sub-module, and the upper tube and the lower tube are fully controlled power semiconductor devices or parallel connections of the devices.

[0013] According to some embodiments, the connection network includes a parallel connection network or a series connection network, the parallel connection network includes N diode units, the anodes of the N diode units are connected as input terminals of the connection network, and the cathodes of the N diode units are sequentially led out to become N output terminals of the connection network, and the series connection network includes: A method 1 including N diode units, the N diode units being connected in series in the same direction, the anode of the first diode unit being the input terminal of the connection network, and the cathode of the Nth diode unit being successively pulled out to be the output terminal of the connection network; and (2) a method 2 including N-1 diode units, the N-1 diode units being connected in series in the same direction, the anode of a first diode unit being an input end of the connection network, and the anode of the first diode and the cathode of the N-1th diode unit being successively pulled out to be an output end of the connection network; The diode unit includes a diode or a diode and a resistor and / or an inductance connected in series.

[0014] According to some embodiments, the power supply further includes a bypass switch for connecting the AC terminals of the sub-modules in parallel, and a discharge branch circuit connected in parallel with the commutation circuit and including a resonant circuit consisting of a discharge switch and a discharge resistor and / or an inductance and / or an inductance capacitance connected in series.

[0015] According to some embodiments, the first sub-module is the sub-module with the lowest potential in the commutation circuit. According to another aspect of the present application, there is provided a control method based on the commutation circuit described in any one of the above claims, the control method including a combination of one or more steps of: a batch submodule pre-functional test in which the first energy harvesting power source is started, the discharge switch is closed, and the capacitance unit of the submodule is charged by the connection network and the discharge resistor; a batch submodule sequential pressurization test in which the first energy harvesting power source is started, and a submodule control unit controls the submodule to sequentially output a zero voltage level state, so as to sequentially charge the capacitance unit of the submodule, and a submodule functional test is carried out; a batch submodule rapid discharge test in which, after the batch submodule pre-functional test or the batch submodule sequential pressurization test is completed, the first energy harvesting power source is opened, the discharge switch is closed, and the submodule control unit sequentially turns on power semiconductor devices at corresponding positions in the power unit, so as to sequentially discharge the capacitance unit of the submodule; and a batch submodule discharge bypass test in which, after the batch submodule rapid discharge test is completed, the capacitance unit of the submodule is discharged to a predetermined value, and the bypass switch of the submodule is automatically closed.

[0016] According to some embodiments, the batch sub-module sequential pressure test includes starting up the first energy harvesting power source and charging the capacitance unit of the connected sub-module; after charging reaches a threshold, supplying power to the sub-module control unit; controlling a power semiconductor device at a corresponding position in the power unit by the sub-module control unit to conduct to a zero voltage level state of the power unit and establishing a conduction circuit for the capacitance unit of the adjacent sub-module; the capacitance unit of the first energy harvesting power source / previous stage sub-module charges the capacitance unit of the adjacent sub-module and charges the sub-module control unit of the adjacent sub-module; and charging of the capacitance units of all sub-modules is completed sequentially and N sub-module control units are charged.

[0017] According to some embodiments, in a half-bridge circuit, the zero voltage level state is defined as the lower tube of the power semiconductor device being conductive, and in a full-bridge circuit, the zero voltage level state is defined as the two upper tubes of the power semiconductor device being conductive simultaneously or the two lower tubes of the power semiconductor device being conductive simultaneously.

[0018] According to another aspect of the present application, there is provided a high-voltage operation circuit, comprising: a modularized batch energy capture commutation circuit as described in any one of the above; and a second commutation circuit, wherein the second commutation circuit comprises M sub-modules, and AC terminals of the M sub-modules are connected in series, M being an integer equal to or greater than 2; or comprising the batch energy capture commutation circuit as described in any one of the above; and AC terminals of a first sub-module and a last sub-module of the second commutation circuit are pulled out to serve as AC terminals of the second commutation circuit, and one AC terminal of the batch energy capture commutation circuit and the second commutation circuit are connected via a connecting reactor, and the other AC terminal is short-circuited.

[0019] According to another aspect of the present application, there is provided a control method for the high-voltage operation circuit described above, comprising: a cascade charging control in which the first energy acquisition power source and a connection network are used to charge the capacity units of all sub-modules, and a sub-module control unit operates by taking electricity from the capacity units; and a cascade operation control in which, after the cascade charging control is completed, the batch energy acquisition commutation circuit and the second commutation circuit control voltage and current, and the first energy acquisition power source replenishes lost energy to the batch energy acquisition commutation circuit and the second commutation circuit.

[0020] According to another aspect of the present application, there is provided a flexible DC commutation station low voltage pressurization system, the flexible DC commutation station including a flexible DC commutation valve and a valve controller, the flexible DC commutation valve includes three parallel phase bridge arms, the phase bridge arms are a series connection of an upper bridge arm and a lower bridge arm, the positive end of the upper bridge arm is connected to a DC positive electrode, the negative end of the upper bridge arm is connected to a positive end of the lower bridge arm, and the negative end of the lower bridge arm is connected to a DC negative electrode, according to a grounding manner of the flexible DC commutation valve, the corresponding upper bridge arm or lower bridge arm or phase bridge arm is arranged as a batch energy acquisition commutation circuit as described in any one of the above, and the other bridge arms are arranged as a commutation circuit of a sub-module connected in series, and the valve controller communicates with a sub-module control unit for controlling the operation of the sub-module.

[0021] According to some embodiments, the correspondence between the arrangement manner and the grounding manner includes: the DC negative pole of the flexible DC rectifier valve is grounded, and at least one lower bridge arm or phase bridge arm is arranged as a batch energy harvesting diversion circuit; the DC positive pole of the flexible DC rectifier valve is grounded, the first energy harvesting power source is isolated from the capacitance unit through an isolation module, and the upper bridge arm or the lower bridge arm or the phase bridge arm is arranged as a batch energy harvesting diversion circuit; when the absolute values ​​of the ground voltages of the DC positive pole and the DC negative pole of the flexible DC rectifier valve are equal to or close to each other, the upper bridge arm or the phase bridge arm is arranged as a batch energy harvesting diversion circuit; the flexible DC rectifier valve is not grounded or is grounded through a grounding switch, and the grounding switch is disconnected, and the upper bridge arm or the lower bridge arm or the phase bridge arm is arranged as a batch energy harvesting diversion circuit.

[0022] According to another aspect of the present application, there is provided a control method for a low voltage pressurization system of a flexible DC commutation station as described in any one of the above, comprising: the first energy harvesting power source charges the DC capacity of the sub-module arranged as a batch energy harvesting commutation circuit, the batch energy harvesting commutation circuit is defined as a charging bridge arm; after the charging of the charging bridge arm is completed, the charging bridge arm starts up and outputs a controllable voltage to charge another bridge arm of the flexible DC commutation valve; after the charging of the other bridge arm is completed, the upper bridge arm and the lower bridge arm of any phase are controlled as a voltage source to apply a DC voltage equally to the DC positive electrode and the DC negative electrode, and the process is defined as a pressurization process.

[0023] According to some embodiments, the power supply further includes a first high-voltage switch connected in series with the first energy harvesting power source, and after charging of the three-phase bridge arm is completed, the first high-voltage switch is disconnected, the three-phase bridge arm is unlocked, the DC positive pole and the DC negative pole present a DC voltage, and the midpoint of the three-phase bridge arm presents a three-phase AC voltage.

[0024] According to some embodiments, the method further includes performing a withstand voltage test and / or sampling calibration on the DC, AC device or AC-DC line during the energization, and ensuring the safety of the device using rapid overcurrent protection of the bridge arm and / or short circuit protection of the power semiconductor device if a dielectric breakdown fault occurs during the energization.

[0025] According to another aspect of the present application, there is provided a method for field testing of a diverter valve, the diverter valve including six bridge arms and a valve control unit, the bridge arms including the diverter circuit described in any one of the above claims, the diverter circuit including N sub-modules, the sub-modules being connected to the valve control unit by optical fibers, the field testing method including: connecting the N output terminals of the connection network to the positive poles of the capacitance units of the N sub-modules; starting up the first energy harvesting power source; identifying whether the physical location of the valve control unit is consistent with the sub-module with which communication is established; acquiring a batch energy, and the sub-modules performing a functional test, or the valve control unit updating a program. Effect of the Invention

[0026] According to exemplary embodiments, the present application has one or more of the following beneficial effects.

[0027] (1) This application provides a modularized commutation circuit capable of batch energy harvesting, and the sub-module capacity is divided into two capacity combinations, which can be flexibly adapted according to the design of the internal power supply unit, one is the capacity that is quickly charged to power the sub-module control unit, or the charging method equivalent to the actual driving situation, while adopting less external power supply and lower voltage to ensure the safety of equipment and personnel. After the sub-module control unit is powered on, a communication peer test can be performed, and the step-by-step test method can reduce the test risk and improve the test reliability.

[0028] (2) This application provides a power push-pull solution for two commutation chains, which uses a low-voltage power supply to supply energy to charge one commutation chain, and uses the output voltage of one commutation chain to charge another commutation chain. By simply adding a connecting reactor, power push-pull between the two commutation chains can be realized, and the connecting reactor can also be the bridge reactor used in the process. This solution is low-cost and highly reliable, and solves the problem that existing commutation chains are difficult to conduct high-voltage and high-power operating tests.

[0029] (3) The low-pressure pressurization testing system and control method of the present application can perform batch inspection of sub-modules, thereby improving testing efficiency. In addition, the system automatically opens the sub-module bypass switch, eliminating the risk of insufficient manual opening.

[0030] It is to be understood that the foregoing general description and the following detailed description are merely exemplary and are not restrictive of the present application. [Brief description of the drawings]

[0031] The above and other objects, features, and advantages of the present application will become more apparent by describing in detail exemplary embodiments thereof with reference to the drawings. The drawings described below are merely some embodiments of the present application and are not intended to limit the present application. [Figure 1]FIG. 1 is a diagram illustrating a modularized commutation circuit capable of harvesting batch energy according to an embodiment of the present application. [Diagram 2] FIG. 2 is a configuration diagram of a capacitance unit according to an embodiment of the present application. [Figure 3a] FIG. 2 is a diagram showing the configuration of a power unit including a half-bridge circuit according to an embodiment of the present application. [Figure 3b] FIG. 1 is a diagram showing the configuration of a power unit including a full-bridge circuit according to an embodiment of the present application. [Figure 3c] FIG. 2 is a diagram showing the configuration of a power unit according to the embodiment of the present application. [Figure 4] FIG. 2 is a configuration diagram of a high impedance type interface unit according to an embodiment of the present application. [Diagram 5] FIG. 2 is a block diagram of an interface unit according to an embodiment of the present application. [Figure 6] FIG. 2 is a configuration diagram of a transformer unit according to an embodiment of the present application. [Figure 7] FIG. 2 is a configuration diagram of another transformer unit according to an embodiment of the present application. [Figure 8] FIG. 2 is a diagram illustrating a connection network configuration in a parallel connection method according to an embodiment of the present application. [Figure 9a] FIG. 2 is a diagram showing a connection network configuration in a series connection system according to an embodiment of the present application. [Figure 9b] 11 is a diagram showing a connection network configuration according to still another embodiment of the present invention; [Figure 10] 1 is a connection network configuration diagram of a series connection method for multiple first energy harvesting power sources according to an embodiment of the present application; [Figure 11] FIG. 1 is a diagram illustrating a composite circuit system configuration of a modularized commutation circuit capable of harvesting batch energy according to an embodiment of the present application. [Figure 12] 2 is a flowchart of a charging control method for a modular commutation circuit capable of batch energy harvesting according to an embodiment of the present application. [Figure 13] 1 is a circuit diagram of a diverter valve low-pressure pressurization test system according to an embodiment of the present application. FIG. [Figure 14]FIG. 11 is a circuit diagram of another diverter valve low-pressure pressurization test system according to an embodiment of the present application. [Figure 15] 1 is a flowchart of a method for controlling a batch sub-module functional pre-test according to an exemplary embodiment. [Figure 16] FIG. 1 is a schematic diagram of a sub-module charging circuit according to an exemplary embodiment. [Figure 17] 1 is a flowchart of a method for controlling a batch sub-module sequential pressurization test in accordance with an illustrative embodiment. [Figure 18] 1 is a flowchart of a method for controlling a batch sub-module rapid discharge test according to an exemplary embodiment. [Figure 19] 1 is a flowchart of a method for controlling a batch sub-module discharge bypass test in accordance with an exemplary embodiment. [Figure 20] FIG. 2 is a schematic diagram of a diverter valve high pressure operation circuit according to an embodiment of the present application. [Figure 21] FIG. 2 is a schematic diagram of another diverter valve high pressure operation circuit according to an embodiment of the present application. [Figure 22a] FIG. 2 is a schematic diagram of a diode unit according to an embodiment of the present application. [Figure 22b] FIG. 2 is a schematic diagram of another diode unit according to an embodiment of the present application. [Figure 23] FIG. 2 is a schematic diagram of a field test system for a diverter valve high pressure operation circuit according to an embodiment of the present application. [Figure 24] FIG. 2 is a schematic diagram of a field test system for another diverter valve high pressure operation circuit according to an embodiment of the present application. [Diagram 25] FIG. 2 is a schematic diagram of a field test system wiring for a diverter valve high pressure operation circuit according to an embodiment of the present application. [Figure 26] FIG. 1 is a schematic diagram of a single bridge arm wiring of a field test system for a diverter valve high pressure operation circuit according to an embodiment of the present application. [Figure 27] 4 is a flowchart of a control method for a diverter valve high pressure operation circuit according to an embodiment of the present application. [Figure 28] 4 is a flow chart of sequence control start-up logic according to an embodiment of the present application. [Figure 29] FIG. 2 is a schematic diagram of a DC charging logic flow according to an embodiment of the present application. [Diagram 30] 4 is a flowchart of a cascade operation control according to an embodiment of the present application. [Diagram 31] 4 is a flowchart of post-operation bypass inspection according to an embodiment of the present application. [Diagram 32] 4 is a flowchart of cascade operation control bypass inspection according to an embodiment of the present application. [Diagram 33] FIG. 1 is a schematic diagram of a flexible DC commutation station low voltage pressurization system according to an embodiment of the present application. [Diagram 34] FIG. 2 is a schematic diagram of another flexible DC commutation station low voltage pressurization system according to an embodiment of the present application. [Diagram 35] FIG. 2 is a schematic diagram of another flexible DC commutation station low voltage pressurization system according to an embodiment of the present application. [Diagram 36] FIG. 2 is a schematic diagram of another flexible DC commutation station low voltage pressurization system according to an embodiment of the present application. [Figure 37a] FIG. 1 is a schematic diagram of a low voltage power supply according to an embodiment of the present application. [Figure 37b] FIG. 2 is a schematic diagram of another low-voltage power supply according to an embodiment of the present application. [Figure 37c] FIG. 2 is a schematic diagram of another low-voltage power supply according to an embodiment of the present application. [Figure 38] 4 is a flowchart of a first energy acquisition power source charging control method according to an exemplary embodiment. [Figure 39] 4 is a flowchart of a bridge arm active pressure equalization control method according to an embodiment of the present application. [Diagram 40] 4 is a flowchart of a split-phase DC pressurization control method according to an embodiment of the present application. [Diagram 41] 2 is a flow chart of a method for controlling low voltage boosting in a flexible DC commutation station according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Next, exemplary embodiments will be described in more detail with reference to the drawings. However, the exemplary embodiments can be implemented in various forms, and should not be understood to be limited to the embodiments described herein. On the contrary, by providing these embodiments, the present application is comprehensive and complete, and fully conveys the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the drawings indicate the same or similar parts, and therefore repeated description will be omitted.

[0033] The flowcharts illustrated in the drawings are merely exemplary illustrations and do not necessarily include all contents and operations / steps, nor do they necessarily have to be performed in the order described. For example, some operations / steps may be separated, while other operations / steps may be combined or partially combined, so that the order of actual execution may vary according to actual circumstances.

[0034] The terms "first", "second", etc. in the specification and claims of this application and in the drawings described above are intended to distinguish different objects and not to describe a particular order. Furthermore, the terms "comprise" and "have", and any variations thereof, are intended to be inclusive without exclusion. For example, a process, method, system, product, or facility 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 that are inherent to those processes, methods, products, or facilities.

[0035] Those skilled in the art should understand that the drawings are only schematic diagrams of exemplary embodiments, and the modules or flows in the drawings are not necessarily required to implement the present application, and therefore should not be used to limit the protection scope of the present application.

[0036] The following describes an embodiment of the apparatus of the present application, which can be used to carry out the embodiment of the method of the present application. For details not disclosed in the embodiment of the apparatus of the present application, reference can be made to the embodiment of the method of the present application.

[0037] FIG. 1 is a diagram showing a configuration of a modular commutation circuit capable of harvesting batch energy according to an embodiment of the present application.

[0038] A modularized commutation circuit capable of batch energy harvesting includes N submodules, in which AC terminals of the N submodules are connected in series, and unconnected AC terminals of a first submodule and a last submodule are pulled out to serve as AC terminals of the commutation circuit, where N is an integer greater than or equal to 2.

[0039] The sub-module includes a power unit 1, a capacitance unit 2, a transformer unit 3, a sub-module control unit 4, a batch energy acquisition unit, and a bypass switch.

[0040] The power unit 1 includes a power semiconductor device, and the AC terminal of the power unit 1 is pulled out to become the AC terminal of the submodule. As shown in FIG. 2, the capacitance unit 2 is connected in parallel with the power unit 1, and the capacitance unit 2 includes a first DC capacitance C1. The transformer unit 3 is connected to the capacitance unit 2 to obtain energy from the capacitance unit 2, realize DC voltage conversion, and supply power to the submodule control unit 4. The submodule control unit 4 is connected to the transformer unit 3 to control the operation of the power unit 1. The batch energy acquisition unit includes a first energy acquisition power source 6 and a connection network 30. The negative pole of the first energy acquisition power source 6 is connected to the negative pole of the first submodule capacitance unit. The input terminal of the connection network 30 is connected directly or via a current limiting unit to the positive pole of the first energy acquisition power source 6, and the connection network 30 includes N output terminals, and the N output terminals are connected directly or via a current limiting unit to the positive poles of all the capacitance units, and the current limiting unit includes a resistor or / and an inductance. The bypass switch is connected in parallel to the AC terminal of the submodule.

[0041] The power unit 1 includes a half-bridge circuit or a full-bridge circuit, and includes a half-bridge circuit or a full-bridge circuit with two or three power levels.

[0042] According to some embodiments, as shown in FIG. 3a, the half-bridge circuit includes an upper tube and a lower tube, and the lower tube is connected in parallel with the AC output terminals of the sub-module.

[0043] According to some embodiments, as shown in FIG. 3b, a full bridge circuit includes two upper tubes and two lower tubes, in which the upper tubes and the lower tubes are connected in series to form a bridge arm, which is then connected in parallel with the capacitance unit, and the midpoint of the bridge arm is pulled out to serve as the sub-module AC output terminal.

[0044] According to some embodiments, the sub-module power units in the commutation circuit are all the same circuit, all half-bridge circuits, all full-bridge circuits, or a mixed arrangement of full-bridge circuits and half-bridge circuits, and FIG. 3c is a full-bridge type sub-module circuit.

[0045] Optionally, a bypass switch is also connected in parallel with the AC terminals of the submodule, the bypass switch being electrically closed and held closed by a mechanical or magnetic force.

[0046] The zero voltage level state of the power unit is defined as follows: in a half-bridge circuit, the zero voltage level state is defined as the lower tube being conductive; in a full-bridge circuit, the zero voltage level state is defined as the two upper tubes being conductive at the same time or the two lower tubes being conductive at the same time.

[0047] Optionally, the capacitance unit 2 further includes a second DC capacitance C2 and an interface unit 5, where the interface unit 5 is connected between the first DC capacitance C1 and the second DC capacitance C2, and the second DC capacitance C2 is connected between the interface unit 5 and the transformer unit 3. The configuration method of the interface unit 5 includes a high impedance method or a blocking method.

[0048] In the high impedance method, as shown in FIG. 4, the interface unit 5 includes a resistor and / or a reactance and has an equivalent impedance value greater than 10 kΩ.

[0049] In the blocking mode, as shown in FIG. 5, the interface unit 5 includes a blocking diode unit, the anode of the blocking diode unit points to the positive electrode of the first DC capacitance C1, the cathode of the blocking diode unit points to the positive electrode of the second DC capacitance C2, and the blocking diode unit includes a blocking diode or includes a blocking diode and a voltage divider resistor network.

[0050] The transformer unit 3 includes at least one DC converter whose input terminal is connected to the capacitance unit 2, as shown in Fig. 6. If the number of DC converters is greater than one, the output terminals of the DC converters are directly connected in parallel or connected in parallel via a series diode, as shown in Fig. 7.

[0051] The connection network 30 includes a parallel connection network or a series connection network.

[0052] According to some embodiments, the parallel connection network includes N diode units, the anodes of the N diode units are connected as input terminals of the connection network, and the cathodes of the N diode units are sequentially led out to become N output terminals of the connection network, as shown in Fig. 8. The diode units include diodes or diodes and resistors or / and inductances connected in series.

[0053] According to some embodiments, as shown in FIG. 9a, the series connection network includes N-1 diode units, the N-1 diode units are connected in series in the same direction, the anode of the first diode unit is the input terminal of the connection network, and the anode of the N-1th diode unit and the cathode of the N-1th diode unit are successively pulled out to be the output terminal of the connection network.

[0054] According to some embodiments, as shown in Fig. 9b, the series-connected network includes N diode units, the N diode units are connected in series in the same direction, the anode of the first diode unit is the input terminal of the connection network, and the cathode of the Nth diode unit is successively led out to be the output terminal of the connection network. The diode unit includes a diode or a diode and a resistor or / and an inductance connected in series.

[0055] Optionally, when the connection network 30 is a series connection network, the commutation circuit further includes M first energy harvesting power sources 6. The M first energy harvesting power sources 6 are respectively connected in parallel to the capacitance units 2 of each sub-module, where M is an integer, 1≦M≦N-1, and when M≧2, a reverse blocking diode is connected in series to the output terminal of the first energy harvesting power source 6, and the cathode of the reverse blocking diode points to the positive electrode of the capacitance unit 2. As shown in FIG. 10 , in this embodiment, M=2.

[0056] In the present invention, the modularized commutation circuit capable of batch energy harvesting divides the sub-module capacity into two capacity combinations, which can be flexibly adapted according to the design of the internal power supply unit, one is the capacity fast charging, which supplies power to the sub-module control unit, or the charging method equivalent to the actual driving situation, but adopts less external power supply and lower voltage to ensure the safety of equipment and personnel. After the sub-module control unit is powered on, a communication peer test can be performed, and the step-by-step test method can reduce the test risk and improve the test reliability. At the same time, the power supply from the external secondary low-voltage power supply and the sub-module capacity is redundant, which more reliably guarantees the control power supply of the sub-module.

[0057] FIG. 11 is a diagram showing the configuration of a composite circuit system of modular commutation circuits capable of harvesting batch energy according to an embodiment of the present application.

[0058] The composite circuit system includes a modularized commutation circuit capable of batch energy harvesting, a valve-based control unit 50, and a second energy harvesting power source 60. The valve-based control unit 50 communicates with the N sub-module control units 4. The second energy harvesting power source 60 is connected to the AC terminals of the commutation circuit.

[0059] Optionally, the composite circuit system further includes a discharge branch, which is connected in parallel with the second energy harvesting power source 60, and includes a discharge switch 61 and a discharge resistor 62 connected in series, as shown in FIG.

[0060] FIG. 12 is a flowchart of a charging control method for a modular commutation circuit capable of batch energy harvesting according to an embodiment of the present application, which includes the following control flow:

[0061] In S10, the first energy harvesting power source 6 is started up and charges the capacity unit 2 of the connected submodule.

[0062] In S20, after the charge reaches a threshold, the DC converter in the transformer unit 3 is started up to supply power to the submodule control unit 4.

[0063] In S30, the submodule control unit 4 controls the power semiconductor device at the corresponding position in the power unit 1 to be conductive as the power unit zero voltage level state, and establishes a conductive circuit to the capacitance unit of the adjacent submodule.

[0064] In S40, the first energy harvesting power source 6 or / and the capacitance unit of the preceding sub-module charges the capacitance unit of the adjacent sub-module and charges the adjacent sub-module control unit.

[0065] In S50, the charging of the capacitance units of all the sub-modules is completed in sequence, and the N sub-module control units 4 are charged.

[0066] When the jth submodule has a fault or the j+1th submodule control unit detects that it cannot be charged normally, where j is an integer and 1≦j≦N-1, the control flow further includes the following:

[0067] Close the bypass switch of the jth submodule. If the j+1th submodule control unit still cannot be charged normally, terminate charging and check the jth submodule or / and the j+1th submodule. If the j+1th submodule control unit is charged normally, continue charging, mark the jth submodule as faulty, and proceed with further processing.

[0068] FIG. 13 is a block diagram of a modular commutation circuit capable of harvesting batch energy according to still another embodiment of the present invention.

[0069] As shown in FIG. 13, the modularized diversion circuit capable of batch energy harvesting includes a diversion valve, a low-pressure pressurizing unit, and a load unit.

[0070] According to an exemplary embodiment, the diverter valve includes a series connection of AC terminals of N submodules 1, where N is an integer equal to or greater than 1.

[0071] According to an exemplary embodiment, the submodule 1 has a half-bridge circuit or a full-bridge circuit connected in parallel with a capacitance unit and a power device connected in parallel with a bypass switch 2 .

[0072] According to some embodiments, the sub-module 1 further includes a sub-module control unit.

[0073] According to some embodiments, the modularized commutation circuit capable of batch energy harvesting further includes a valve control system in communication with the sub-module control unit.

[0074] According to an exemplary embodiment, the low pressure pressurizing unit comprises a first energy harvesting power source 3 and a connection network 4. The low pressure pressurizing unit is connected to the capacitive units of the sub-module.

[0075] According to an exemplary embodiment, the load unit includes a discharge switch 5 and a discharge resistor 6, the load unit being connected in parallel with the diverter valve.

[0076] The first energy harvesting power source is started up, closes a discharge switch, and simultaneously charges the capacitance units of all the sub-modules through a connecting network and a discharge resistor.

[0077] According to some embodiments, the negative pole of the first energy harvesting power source is connected to the negative pole of the first sub-module capacitance unit, the input terminal of the connection network is directly connected to the positive pole of the first energy harvesting power source, and the connection network includes N output terminals, each of which is connected to the positive pole of every capacitance unit.

[0078] According to some embodiments, the connection network includes two connection schemes: a parallel scheme and a serial scheme.

[0079] According to an exemplary embodiment, Fig. 13 shows a parallel connection network, which includes N diodes, the anodes of the N diode units are connected together to form input terminals of the connection network, and the cathodes of the N diode units are successively led out to form N output terminals of the connection network.

[0080] According to some embodiments, the modular commutation circuit capable of batch energy harvesting may implement one or more of the following control methods. 1. Batch sub-module function pre-test: the first energy acquisition power supply is started, the discharge switch is closed, and all the sub-module capacitance units are charged by the connection network and the discharge resistor. 2. Batch sub-module sequential pressure test: the first energy acquisition power supply is started, the valve control unit controls the sub-module to sequentially output the zero voltage level state, the sub-module capacitance unit is charged one by one, and the sub-module function test is carried out. 3. Batch sub-module rapid discharge test: the first energy acquisition power source is cut off, the discharge switch is closed, and the valve control unit sequentially turns on the power semiconductor devices at the corresponding positions in the power unit to discharge the sub-module capacitance units one by one. 4. Batch sub-module discharge bypass test: When the sub-module capacity unit discharges to a set value, it will automatically close this sub-module bypass switch.

[0081] According to some embodiments, the above control methods can be combined with one or more of the following: 1. First, carry out a batch sub-module function preliminary test and / or a batch sub-module sequential pressure test, and after the test is completed, the sub-module capacitance unit is naturally discharged. 2. Firstly, carry out a batch sub-module function preliminary test and / or a batch sub-module sequential pressure test, and then carry out a batch sub-module rapid discharge test, and the sub-module capacity unit is rapidly discharged after the test is completed. 3. Firstly, carry out the batch sub-module function preliminary test and / or the batch sub-module sequential pressure test, and then carry out the batch sub-module rapid discharge test and the batch sub-module discharge bypass test. After the test is completed, the sub-module capacitance unit is rapidly discharged and the bypass switch is closed. 4. First perform a batch submodule function pre-test and / or a batch submodule sequential pressure test, then perform a batch submodule rapid discharge test and a batch submodule discharge bypass test, after the test is completed, the submodule capacitance unit rapidly discharges and closes the bypass switch, then manually opens the bypass switch, further perform a batch submodule function pre-test and / or a batch submodule sequential pressure test, after the test is completed, the submodule capacitance unit naturally discharges, or perform a batch submodule function pre-test and / or a batch submodule sequential pressure test, then perform a batch submodule rapid discharge test, after the test is completed, the submodule capacitance unit rapidly discharges, and check whether the bypass switch opening is in the predetermined position.

[0082] The connection network of Fig. 14 is a serial connection. As shown in Fig. 14, the connection network includes N-1 diode units, the N-1 diode units are connected in series in the same direction, the anode of the first diode unit is the input terminal of the connection network, and the anode of the N-1th diode unit and the cathode of the N-1th diode unit are successively pulled out to be the output terminal of the connection network.

[0083] FIG. 15 illustrates a flow chart of a method for controlling a batch sub-module functional pre-test according to an exemplary embodiment.

[0084] In S410, the first energy harvesting power source is started up and closes the load switch.

[0085] According to an exemplary embodiment, the first energy harvesting power source is activated and closes the load switch of the load unit, forming a closed circuit.

[0086] In S420, the first energy harvesting power source charges the sub-module capacitance unit through the connection network and the load resistance of the load unit.

[0087] In S430, after the sub-module capacitive unit voltage reaches the wake-up threshold, the sub-module control unit wakes up.

[0088] In S440, it is checked whether the valve control unit and the submodule control unit are communicating normally.

[0089] According to an exemplary embodiment, the valve control unit and the sub-module control unit are checked for normal communication, and if a communication failure occurs, the faulty sub-module is located.

[0090] In the S450, sub-module functional tests will be carried out.

[0091] In S460, it is determined whether there is a faulty sub-module.

[0092] According to an exemplary embodiment, if a faulty sub-module is detected, proceed to S470, otherwise proceed to S480.

[0093] In S470, the faulty sub-module bypass switch is closed, or the faulty sub-module bypass switch is closed and then the faulty sub-module is checked.

[0094] According to an exemplary embodiment, after detecting a sub-module failure, close the failed sub-module bypass switch, or close the failed sub-module bypass switch and then check the failed sub-module, and then proceed to S410.

[0095] At S480, the process ends.

[0096] FIG. 16 is a schematic diagram of a sub-module charging circuit according to an exemplary embodiment.

[0097] As shown in FIG. 16, the first energy harvesting power source charges the sub-module capacitance unit through the connection network and the load resistance of the load unit.

[0098] According to some embodiments, the capacitance units of N sub-modules can be charged simultaneously.

[0099] FIG. 17 illustrates a flowchart of a method for controlling batch sub-module sequential pressure testing in accordance with an illustrative embodiment.

[0100] At S610, the first energy harvesting power source starts up and charges the first sub-module capacitance unit.

[0101] According to an exemplary embodiment, the first energy harvesting power source charges the capacitance unit of the sub-module that is directly connected to its negative terminal.

[0102] In S620, the first sub-module control unit starts up, causing the power unit to output a zero voltage level and charge the adjacent sub-module capacitance unit.

[0103] According to some embodiments, in a half-bridge circuit, the zero voltage level state is defined as the lower tube conducting, and in a full-bridge circuit, the zero voltage level state is defined as the two upper tubes conducting simultaneously or the two lower tubes conducting simultaneously.

[0104] According to an exemplary embodiment, after charging of the first sub-module capacitance unit is completed, the first sub-module control unit is started up and turns on the power unit of the first sub-module, and the first energy harvesting power source charges the capacitance unit of the adjacent sub-module.

[0105] In S630, the adjacent sub-module control unit is activated to output a zero voltage level state.

[0106] According to an exemplary embodiment, after the charging of the adjacent sub-module capacitance unit is completed, the power unit of the adjacent sub-module outputs a zero voltage level to charge the next adjacent sub-module capacitance unit, thus charging sequentially, charging all the sub-module capacitance units, and activating all the sub-module control units.

[0107] In S640, sub-module functional testing is carried out.

[0108] According to some embodiments, the sub-module functional test includes a capacitive voltage sampling test.

[0109] According to some embodiments, when the network is connected in parallel, the i-th sub-module capacitance unit voltage sampling value V SMI =V S -V D -V G *(i-1) or sampling value Vsmi = Vsm (i-1) -V G and According to some embodiments, when the network is connected in series, the i-th sub-module capacitance unit voltage sampling value V SMI =V S -V D *(i-1)-V G *(i-1) or V SMI =V SM(i-1) -V G -V D and Here, V SM is the i-th submodule capacitance unit voltage sampling value, V SM(i-1) is the (i-1)th submodule capacitance unit voltage sampling value, V S is the first energy harvesting power supply voltage, V D is the diode tube voltage drop, and V G is the tube voltage drop of the power semiconductor device.

[0110] According to some embodiments, the capacitive voltage sampling calibration compares the calculated sampling value based on the above theory with the actual sampling value, and determines the test as failing if the deviation is higher than a threshold value.

[0111] According to some embodiments, the sub-module functional test includes a cross-communication calibration, and the cross-communication includes two types. 1) The sub-module control unit and the adjacent sub-module control unit perform two cross communications, and simultaneously communicate with two different channels of the valve control unit. 2) Multiple sub-module control units communicate in series, and the first and last two sub-module control units communicate with two different channels of the valve control unit.

[0112] In cross-communication, different sub-module capacitance voltage sampling values ​​are respectively read from the same channel of the valve control unit, and if the data matches the corresponding relationship of the capacitance voltage sampling calibration, it means that the inspection is passed.

[0113] FIG. 18 illustrates a flow chart of a method for controlling a batch sub-module rapid discharge test according to an exemplary embodiment.

[0114] In S710, execution of the batch sub-module preliminary functional test or the batch sub-module sequential pressurization test is completed.

[0115] In S720, the first energy harvesting power source is shut off and the load switch is closed.

[0116] In S730, the power semiconductor devices at the corresponding positions in the submodule power units are sequentially turned on, starting from the first or last.

[0117] According to some embodiments, the power semiconductor device at the corresponding position refers to an upper tube of a half-bridge circuit or a pair tube of a full-bridge circuit.

[0118] According to an exemplary embodiment, the submodule directly connected to the first energy harvesting power source is the first submodule, and the power semiconductor device at the corresponding position in the power unit of the first or last submodule can be turned on.

[0119] In S740, a theoretical voltage value is calculated from the capacitance value of the sub-module capacitance unit, and the discharge voltage of the sub-module capacitance unit is determined.

[0120] According to an exemplary embodiment, if the voltage deviation is higher than a threshold, it is logged and an alarm is generated.

[0121] FIG. 19 illustrates a flow chart of a method for controlling a batch sub-module discharge bypass test in accordance with an exemplary embodiment.

[0122] In S810, a batch sub-module rapid discharge test was performed.

[0123] In S820, when the sub-module capacitance unit is discharged to a low voltage threshold, the valve control unit or the sub-module control unit commands the sub-module bypass switch to close.

[0124] FIG. 20 is a schematic diagram of a high-pressure operation circuit of a diverter valve according to an embodiment of the present application, which includes two diverter circuits, a connecting reactor 2, and one or two connecting networks 1.

[0125] The two commutation circuits each include N submodules 3 and M submodules 3, where N and M are integers greater than or equal to 1, and one AC terminal of the two commutation circuits is connected via a connecting reactor 2, and the other AC terminal of the two commutation circuits is short-circuited.

[0126] The submodule 3 includes a DC capacitance C1 and a power unit connected in parallel, and the power unit includes a half-bridge circuit or / and a full-bridge circuit made of power semiconductor devices. The AC terminals of the submodules 3 are connected in series, and the AC terminals of the first submodule and the last submodule are drawn out as AC terminals of a commutation circuit, one AC terminal of the two commutation circuits is connected via a connecting reactor 2, and the other AC terminal is short-circuited. The first submodule is a submodule connected to the anode side of the connection network, and the last submodule is a submodule connected to the cathode side of the connection network. The submodules further include a submodule control unit that controls the operation of the power unit.

[0127] The connection network 1 comprises at least N−1 or at least M−1 diode units 4 .

[0128] The diode units 4 are connected in series in the same direction, the cathode end of the connection network 1 is connected to the positive pole of the DC capacitance C1 of the last submodule, and the anode ends of all the diode units 4 correspond one-to-one to the positive pole of the DC capacitance C1 of the submodule 3 of the corresponding commutation circuit or are connected via a first current limiter. The diode unit includes a diode, with the diode anode facing the anode end of the diode unit and the cathode facing the cathode end.

[0129] Optionally, the diverter valve high voltage driving circuit further includes at least one first energy harvesting power source 5, which is connected in parallel with the DC capacity of the first sub-module of the corresponding diverter circuit. The first energy harvesting power source 5 includes a power supply unit or a power supply unit and a diode connected in series, and the power supply unit includes a DC power supply or an AC power supply and a rectifier.

[0130] The output voltage of the first energy harvesting power source 5 is fixed or adjustable, and in this embodiment, the output voltage of the first energy harvesting power source 5 is smaller than the withstand voltage value of the sub-module power unit semiconductor device. For example, when the withstand voltage value of the power semiconductor device is 3300V, the first energy harvesting power source 5 can adopt an output voltage of 1500V.

[0131] As shown in FIG. 20, when one commutation circuit arranges a connection network, the number of the first energy harvesting power source is 1, and the power source is connected in parallel with the DC capacity of the first sub-module of the commutation circuit that arranges the connection network.

[0132] As shown in FIG. 21, when two commutation circuits are arranged in a connection network, the number of first energy harvesting power sources is two, and the power sources are respectively connected in parallel with the DC capacitances of the first sub-modules of the two commutation circuits.

[0133] The invention according to this embodiment can solve the power supply problem of many sub-modules by using the first energy harvesting power source with low voltage output, and can realize charging of the entire commutation circuit through the low voltage output, thereby reducing the test conditions and requirements, and can be applied even when the site does not have a high voltage high power power source.

[0134] Optionally, the diode unit 4 further includes a second current limiter for mainly limiting current impulse during the charging process, as shown in FIG. 22a, the second current limiter is connected in series with the diode, and the second current limiter includes a resistor and / or an inductor.

[0135] Optionally, as shown in FIG. 22b, the diode unit further includes an isolation switch connected in series with the diode, and the on / off of the isolation switch is controlled by the control unit of the sub-module.

[0136] FIG. 23 is a schematic diagram of a field test system for a high pressure operation circuit of a diverter valve according to an embodiment of the present application, the field test system for a high pressure operation circuit of a diverter valve includes at least one high pressure operation circuit of a diverter valve.

[0137] Here, the two diversion circuits of the diversion valve high pressure operation circuit are installed in a valve tower type and defined as the engineering valve tower 10.

[0138] As shown in Figure 23, a cross member is built between the supporting insulators of the engineering valve tower, and the connecting reactor 2 is attached to the cross member 11. The cross member can be built at the N1, N2, N3 insulating supporting positions, and the connecting reactor 2 can also be placed on the ground independently.

[0139] As shown in FIG. 24, an insulation distance d1 is maintained between the connection reactor 2 and the ground potential, and insulation distances d2 and d3 are maintained between the connection reactor 2 and the two engineering valve towers, respectively.

[0140] The connecting reactor 2 includes a bridge arm reactor or a combination of bridge arm reactors, and the connecting reactor 2 accesses between the engineering valve towers 10.

[0141] In actual engineering applications, the wiring scheme includes three-phase six bridge arms, as shown in FIG. 25. In this embodiment, each bridge arm includes two engineering valve towers 10. One end of the series connection of the two engineering valve towers connects AC, and the other end is pulled out and connected to the bridge arm reactor 2 through the wall through-hole sleeve 12, and then connected to the positive pole of the commutation valve.

[0142] According to some embodiments, the existing wiring scheme can also be modified, and the bridge arm reactor is used as the connecting reactor 2, and the modified wiring is shown in FIG. 26 by taking one bridge arm as an example. The operation circuit configured after the modification is the operation circuit shown in FIG.

[0143] FIG. 27 is a flowchart of a control method for the diverter valve high-pressure operation circuit according to an embodiment of the present application, which includes two control modes: cascade charging control and cascade operation control.

[0144] In the cascade charging control, the first energy acquisition power source and the cascade energy supply chain are used to charge the DC capacities of all the sub-modules, and the control units of the sub-modules take electricity from the DC capacities before operating.

[0145] In the cascade charging control, when the number of the first energy harvesting power sources is one, the commutation circuit connected to the first energy harvesting power source is the first commutation circuit, and the other commutation circuit is the second commutation circuit. The first commutation circuit first executes the sequence control startup logic, and after the startup is completed, executes the DC charging logic, controls the output voltage, and charges the sub-module of the second commutation circuit. When the number of the first energy harvesting power sources is two, the two commutation circuits respectively execute the sequence control startup logic.

[0146] According to some embodiments, the sequence control startup logic includes: starting up the first energy harvesting power supply, charging the DC capacitance of the first sub-module, and powering on and running the first sub-module control unit, controlling the power semiconductor device at the corresponding position in the power unit to be conductive by the control unit of the sub-module, outputting a zero voltage level state, establishing a conductive circuit for the DC capacitance of the adjacent sub-module, charging the DC capacitance of the adjacent sub-module, and powering on the sub-module control unit, as shown in FIG. 28 , and the DC capacitance charging of all sub-modules is completed sequentially, and the sub-module control unit is charged.

[0147] According to some embodiments, the DC charging logic includes: adjusting the output voltage of the commutation circuit connected to the first energy harvesting power source, gradually increasing the voltage from zero, charging the DC capacitance of the second commutation circuit sub-module until powering on the second commutation circuit sub-module control unit, as shown in FIG. 29 ; and controlling the number of sub-modules in the second commutation circuit that are put into the charging circuit so that the DC capacitance voltage of the second commutation circuit sub-module reaches a predetermined value.

[0148] In the cascade operation control, after the cascade charging control is completed, the two diversion circuits control the voltage and current, and reproduce the sub-module voltage and current stress of the diversion circuit, and the first energy acquisition power source continuously replenishes the energy lost due to the two diversion circuits in this process.

[0149] According to some embodiments, the cascade operation control includes, as shown in FIG. 30 , unlocking and starting up one of the commutation circuit submodule power units to output a target AC voltage value, and when the AC voltage is stable, unlocking and starting up another commutation circuit submodule power unit to control the current flowing through the connected reactor to the target value, and when the system is stable, detecting the current, controlling the voltage and current of the commutation circuit, and comparing it with a predetermined value to determine whether the test requirements are met.

[0150] Here, when the control method is applied to a field test system, the setting of the AC voltage target value is adjusted according to the insulation level of the connected reactor and d1, d2, and d3.

[0151] Optionally, the control method further includes bypass switch inspection control performing cascade operation control bypass inspection and bypass inspection after operation is terminated to test whether the bypass switch operates normally.

[0152] According to some embodiments, the bypass inspection after the end of operation includes ending the cascade operation control, stopping the output of the first energy harvesting power source, sequentially bypassing the sub-modules of the two commutation circuits, and checking whether the bypass switch is operating correctly, as shown in FIG. 31 .

[0153] According to some embodiments, the cascade operation control bypass inspection includes: entering the cascade operation control, as shown in FIG. 32 ; controlling the continuous bypass operation of the bypass switches of the sub-modules in the two commutation circuits after stabilization; and reducing the AC voltage target value during the cascade operation control if it is detected that the operation state after the operation is normal; otherwise, performing bypass inspection after the operation is terminated.

[0154] The control method of this embodiment includes start-up charging, cascade operation control and bypass inspection. The control method covers important items of diversion valve testing. Before the filing of this application, only the relevant tests of the sub-modules could be completed during the on-site testing of the diversion valve. The method provided by this application realizes the diversion circuit testing and provides reliability guarantee for the engineering application of the diversion valve.

[0155] FIG. 33 is a schematic diagram of a flexible DC commutation station low voltage boosting system according to an embodiment of the present application.

[0156] This embodiment provides a flexible DC commutation station low-voltage pressurization system, and the flexible DC commutation station includes a flexible DC commutation valve and a valve controller. As shown in Figure 33, the flexible DC commutation valve includes three parallel-connected phase bridge arms A, B, and C. The phase bridge arms A, B, and C are connected in series with upper bridge arms and lower bridge arms, and the positive end of the upper bridge arm is electrically connected to the DC positive pole, the negative end of the upper bridge arm is electrically connected to the positive end of the lower bridge arm, and the negative end of the lower bridge arm is electrically connected to the DC negative pole.

[0157] According to some embodiments, the low voltage of the low pressure pressurization system is 300V-1500V.

[0158] As shown in FIG. 33, taking the A phase as an example, the upper bridge arm and the lower bridge arm have similar structures, so the specific structure of the lower bridge arm is not shown. The upper bridge arm includes N submodules 1 and a bridge reactor 2, where N is an integer equal to or greater than 2. The submodule 1 includes two power semiconductor devices and one capacitance, and the first power semiconductor device and the second power semiconductor device are connected in series in the same direction and then connected in parallel with the capacitance. The DC positive pole is electrically connected to the bridge arm reactor 2, the other end of the bridge arm reactor 2 is electrically connected to the series midpoint of the two power semiconductor devices of the submodule 1, and the other end of the second power semiconductor device is connected to the series midpoint of the two power semiconductor devices of the next submodule, and the submodules are connected in series in sequence, and one end of the second power semiconductor device of the Nth submodule is connected to the series midpoint of the two power semiconductor devices of the submodule of the lower bridge arm, and one end of the second power semiconductor device of the Nth submodule of the lower bridge arm is electrically connected to the bridge arm reactor and then electrically connected to the DC negative pole.

[0159] According to an exemplary embodiment, the circuit configurations for phases A, B, and C are similar.

[0160] According to some embodiments, the sub-module 1 may be a half-bridge circuit, a full-bridge circuit, a three-power level circuit, or a combination thereof, and the sub-module 1 further includes a sub-module controller capable of controlling the operation of the sub-module.

[0161] According to an exemplary embodiment, a valve controller communicates with the sub-module controller and controls operation of the flexible DC commutation station low voltage boosting system.

[0162] 33, the low-pressure pressurizing system 3 includes a first energy harvesting power source 4 and a connection network 5. The positive terminal of the first energy harvesting power source 4 is electrically connected to the positive terminal of the connection network 5.

[0163] According to some embodiments, the connection network 5 comprises at least N-1 or 2N-1 diode units.

[0164] As shown in FIG. 33, in this embodiment, the connection network 5 is connected to the A phase of the upper bridge arm and includes N-1 diode units.

[0165] According to some embodiments, the connection network 5, when connected to a phase bridge arm, includes 2N-1 diode units.

[0166] According to some embodiments, the diode unit includes a diode or a diode is connected in series with the current limiting unit 6 .

[0167] As shown in FIG. 33, in this embodiment, when the diode unit and the submodule are connected, the connection is made via a current limiting unit.

[0168] According to an exemplary embodiment, the diode units are connected in series in the same direction, and the diode anode end is defined as the anode end of the diode unit, and the diode cathode end is defined as the cathode end.

[0169] According to some embodiments, the anode ends of all the diode units and the cathode end of the last diode unit constitute draw-out points equal to the number of submodules, and are connected in one-to-one correspondence to the anodes of the submodule DC capacitances or connected in one-to-one correspondence via the current limiting units 6.

[0170] As shown in FIG. 33, in this embodiment, the anode terminals of all the diode units and the cathode terminal of the last diode unit form draw-out points equal to the number of submodules, and are connected in one-to-one correspondence to the positive electrodes of the submodule DC capacitances via the current limiting unit 6.

[0171] According to some embodiments, the current limiting unit 6 consists of a resistor and / or an inductor.

[0172] According to an exemplary embodiment, when the absolute values ​​of the DC positive and negative poles of the flexible DC rectifier valve are equal or close to each other in terms of ground voltage, the first energy harvesting power supply 4 is connected in parallel with the negative sub-module DC capacitance of any upper bridge arm, and the connecting network is sequentially connected to the positive poles of the DC capacitances of other sub-modules of this bridge arm.

[0173] As shown in FIG. 34, when the DC negative pole of the flexible DC commutation valve is grounded, the first energy harvesting power supply 4 is connected in parallel with the sub-module DC capacitance at the negative end of any lower bridge arm or phase bridge arm, and the connection network is sequentially connected to the DC capacitance positive pole of other sub-modules of this bridge arm.

[0174] 35, when the DC positive pole of the flexible DC commutation valve is grounded, the first energy harvesting power supply 4 is connected in parallel with the sub-module DC capacitance of the negative end of any upper bridge arm, lower bridge arm, or phase bridge arm through the isolation module 7, and the connection network is sequentially connected to the DC capacitance positive pole of other sub-modules of this bridge arm. According to some embodiments, the isolation module 7 is an isolation transformer.

[0175] As shown in FIG. 36, when the flexible DC commutation valve is not grounded, or is grounded through the grounding switch and the grounding switch 8 is cut off, the first energy harvesting power supply 4 is connected in parallel with the negative sub-module DC capacitance of any upper bridge arm, lower bridge arm, or phase bridge arm, and the connection network is sequentially connected to the positive pole of the DC capacitance of other sub-modules of this bridge arm.

[0176] As shown in FIG. 37a, the first energy harvesting power source is a DC power source with its negative terminal grounded.

[0177] As shown in FIG. 37b, the first energy harvesting power source includes a diode 9 and a DC power source, and the anode of the diode 9 is connected to the positive pole of the DC power source.

[0178] As shown in FIG. 37c, the first energy harvesting power source outputs through the series first high voltage switch 10, and the insulation voltage level of the first high voltage switch 10 is equal to or higher than the AC side voltage of the flexible DC commutation valve.

[0179] FIG. 38 illustrates a flowchart of a method for controlling charging of a first energy harvesting power source according to an exemplary embodiment.

[0180] In S601, the first energy harvesting power source is started, charging the sub-module DC capacitance connected to the first energy harvesting power source through the charging bridge arm, and powering on the sub-module controller for operation.

[0181] According to an exemplary embodiment, taking the charging of the A-phase bridge arm by the first energy harvesting power source as an example, the first energy harvesting power source is started up, charges the DC capacitance of the Nth submodule of the A-phase bridge arm, powers on the Nth submodule controller of the upper bridge arm of the A-phase, and controls the second power semiconductor of the Nth submodule to be conductive.

[0182] In S603, the sub-module is controlled to output a zero voltage level, and a charging circuit is established for the DC capacitance of the adjacent sub-module, and the DC capacitance voltage of the adjacent sub-module reaches the start-up value Vc1.

[0183] According to an exemplary embodiment, the submodule controller of the upper bridge arm of phase A controls the submodule to output a zero voltage level, establishes a charging circuit for the DC capacitance of the adjacent submodule, i.e., makes the second power semiconductor device of the Nth submodule of the upper bridge arm of phase A conduct, and makes the DC capacitance voltage of the N-1th submodule of the upper bridge arm of phase A reach the start-up value Vc1, so as to control the N-1th submodule controller to power on and make the second power semiconductor device of the N-1th submodule conduct.

[0184] In S605, the charging of the DC capacitance of all the sub-modules is completed in sequence, and all the sub-module controllers of this charging bridge arm are charged.

[0185] According to an exemplary embodiment, the upper bridge arm of phase A completes the charging of the DC capacitance of all the sub-modules in sequence, the DC capacitance voltage of the sub-module of the upper bridge arm of phase A reaches the start-up value Vc1, and the sub-module controllers of this charging bridge arm are all charged.

[0186] FIG. 39 is a flowchart of a bridge arm active voltage sharing control method according to an embodiment of the present application.

[0187] In S701, if the charging bridge arm is an upper bridge arm or a lower bridge arm, another bridge arm in the same phase is described as a charging in-phase bridge arm, for example, if the charging bridge arm is a phase bridge arm, the charging in-phase bridge arm is equivalent to a short circuit.

[0188] According to an exemplary embodiment, taking the charging of the upper bridge arm of phase A by the first energy harvesting power source as an example, the lower bridge arm of phase A is described as a charging in-phase bridge arm.

[0189] In S702, the charging bridge arm sub-module is circulated and charged by the bypass voltage sharing, so that the sub-module DC capacitance voltage reaches the rated value Vc2, and the valve controller controls the charging bridge arm to output the first control voltage source.

[0190] According to an exemplary embodiment, after the DC capacitance voltage of the A-phase upper bridge arm reaches Vc1, the second power semiconductor device of the sub-module of the A-phase upper bridge arm is controlled to be alternately conducted, so that the sub-module DC capacitance voltage reaches a rated value Vc2, and the DC capacitance of the A-phase upper bridge arm outputs a voltage to the first controlled voltage source.

[0191] In S703, a first controlled voltage source is connected in series with the charging common-phase bridge arm to charge the DC capacitances of the bridge arm sub-modules of the other two phases.

[0192] According to an exemplary embodiment, after the upper bridge arm and the lower bridge arm of phase A are connected in series, the DC capacitances of the sub-modules of the upper and lower bridge arms of phases B and C are charged so that the DC capacitance voltages of the sub-modules of the upper and lower bridge arms of phases B and C reach the start-up value Vc1.

[0193] In S704, the other two-phase bridge arm sub-modules perform circulating bypass voltage sharing charging individually or simultaneously so that the sub-module DC capacitance voltage reaches the rated value Vc2.

[0194] According to an exemplary embodiment, after the DC capacitance voltages of the upper and lower bridge arms of phases B and C reach Vc1, the second power semiconductor devices of the sub-modules of the upper and lower bridge arms of phases B and C are controlled to be alternately conductive, so that the sub-module DC capacitance voltages reach the rated value Vc2.

[0195] In S705, it is determined whether the charge bridge arm is a phase bridge arm.

[0196] If the charging bridge arm is a phase bridge arm, the step ends, and if the charging bridge arm is not a phase bridge arm, proceed to the next step.

[0197] In S706, the upper and lower bridge arms of any phase different from the charging bridge arm output the second controlled voltage source and the third controlled voltage source, respectively.

[0198] According to an exemplary embodiment, the valve controller controls the upper and lower bridge arms of any phase different from the charging bridge arm to output the second controlled voltage source and the third controlled voltage source, that is, the upper and lower bridge arms of phase B and phase C output the second controlled voltage source and the third controlled voltage source, respectively.

[0199] In S707, the charging common-phase bridge arm is charged.

[0200] According to an exemplary embodiment, the first controlled voltage source, the second controlled voltage source, and the third controlled voltage source form a loop with the charging common-phase bridge arm to charge the charging common-phase bridge arm, that is, the upper and lower bridge arms of phases B and C charge the lower bridge arm of phase A, so that the DC capacitance voltages of the sub-modules of the upper bridge arm of phase A and the lower bridge arm of phase A reach Vc1.

[0201] In S708, the charging common-phase bridge arm sub-module is charged with cyclic bypass voltage sharing until the DC capacitance voltage of the sub-module reaches the rated value Vc2.

[0202] According to an exemplary embodiment, after the DC capacitance voltage of the lower bridge arm of phase A reaches Vc1, the second power semiconductor device of the sub-module of the lower bridge arm of phase A is controlled to be alternately conducted, so that the DC capacitance voltage of the sub-module reaches a rated value Vc2.

[0203] In S709, the process ends.

[0204] According to an exemplary embodiment, the bridge arm active voltage sharing control is completed and the process ends.

[0205] FIG. 40 is a flowchart of a split-phase DC pressurization control method according to an embodiment of the present application.

[0206] In S801, the bridge arm active voltage sharing control step is completed.

[0207] The bridge arm active voltage sharing control steps are shown in FIG.

[0208] In S803, the voltage source for controlling the output of any one of the phase or multi-phase bridge arms is adjusted to output a DC voltage 2Udc to the entire phase bridge arm.

[0209] According to an exemplary embodiment, the first controlled voltage source, the second controlled voltage source and the third controlled voltage source all output DC voltages, so that the entire phase bridge arm can output the DC voltage 2Udc.

[0210] According to an exemplary embodiment, the magnitude of the DC voltage Udc can be adjusted, including two methods: a method of adjusting the number of sub-modules of the output voltage Vc2 in the upper or / and lower bridge arm, or a method of adjusting the DC capacity rated voltage value Vc2 of each sub-module in the upper or / and lower bridge arm.

[0211] where Udc=Vc2*P, where P is the number of submodules of output voltage Vc2 in the upper or lower bridge arm. P finally stabilizes to N / 2.

[0212] According to an exemplary embodiment, the controlled voltage source can adjust the rising speed of outputting the DC voltage, and control the discharge current to be less than a predetermined value. In this state, the controlled voltage source charges other bridge arms on the DC bus, and the DC power source in its own submodule is in a discharging state, so if the above speed of outputting the DC voltage is adjusted too quickly, the discharge current will be too large, so it is necessary to select a reasonable rising speed, and control the discharge current to be less than a predetermined value.

[0213] According to an exemplary embodiment, the actual operating situation is simulated, and the second controlled voltage source and the third controlled voltage source are composite voltages Uac1 and Uac2 respectively, and the composite voltage is superimposed by the AC voltage Uac and the DC voltage Udc, where Uac1=Udc+Uac, Uac2=Udc-Uac, and Uac1+Uac2=2Udc.

[0214] According to an exemplary embodiment, the split-phase DC boost control method powers on different phases or switches on different sub-modules, and observes the output voltages and waveforms to determine whether the sub-modules are operating normally.

[0215] FIG. 41 is a flow chart of a method for controlling low voltage boosting in a flexible DC commutation station according to an embodiment of the present application.

[0216] In S910, the bridge arm active voltage sharing step is completed.

[0217] According to an exemplary embodiment, as shown in FIG. 7, once the bridge arm active voltage sharing step is completed, if the first energy harvesting power source has a first high voltage switch 10, the first high voltage switch 10 is turned off.

[0218] In S930, the flexible DC commutation valve is unlocked, the DC positive and negative poles present DC voltage, and the midpoint of the three-phase bridge arm presents three-phase AC voltage.

[0219] In S950, after the sub-module capacitor voltage drops to the threshold, the flexible DC commutation valve is closed to stop the test.

[0220] According to an exemplary embodiment, when the sub-module is in operation and consumes power, causing the capacitive voltage of the sub-module to drop below a certain threshold, the flexible DC commutation valve is closed, stopping the test.

[0221] According to an exemplary embodiment, the present application further has one or more of the beneficial effects of accessibility.

[0222] 1. During pressurization, pressure tests and sampling calibrations should be performed on DC and AC auxiliary equipment. 2. When insulation breakdown occurs during the pressurization process, the rapid overcurrent protection of the bridge arm and / or the short circuit protection of the power semiconductor device are used to ensure the safety of the equipment. The rapid overcurrent protection of the bridge arm detects the bridge arm current by the valve controller, and closes the flexible DC commutation valve and stops the test when the current exceeds the operation threshold. The short circuit protection of the power semiconductor device immediately closes the bypass submodule after the submodule controller detects the occurrence of a short circuit fault in the power device and reports the fault to the valve controller. At the same time, if the number of submodules with faults exceeds a certain number, the flexible DC commutation valve is closed and the test is stopped.

[0223] Although the present application describes how to make and use particular examples, it should be expressly understood that the application is not limited to the details of these examples. On the contrary, these principles can be applied to many other embodiments based on the teachings of the present disclosure.

[0224] It should be noted that the above figures are not intended to be limiting, but merely schematic illustrations of the processes involved in the method according to the exemplary embodiments of the present application. It is to be understood that the processes illustrated in the above figures are not intended to indicate or limit the time sequence of these processes. It is also to be understood that these processes may be performed, for example, synchronously or asynchronously in multiple modules.

[0225] Although exemplary embodiments of the present application have been specifically shown and described, it is to be understood that the present application is not limited to the detailed structure, arrangement, or implementation methods set forth herein. On the contrary, the present application is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A modularized batch energy harvesting commutation circuit, comprising: a batch energy harvesting unit; and N sub-modules, AC terminals of the N sub-modules are connected in series, N being an integer equal to or greater than 2; The sub-module comprises: a power unit including a power semiconductor device and having AC terminals extending therefrom as AC terminals of the submodule; a capacity unit connected in parallel with the power unit, The batch energy capture unit comprises: A first energy harvesting power source, the negative pole of which is connected to the negative pole of the capacitance unit of the first sub-module of the N sub-modules or connected via a current limiting unit; a connection network having an input terminal directly connected to a positive pole of the first energy harvesting power source or connected via a current limiting unit, and N output terminals respectively connected to the positive pole of the capacitance unit or connected via a current limiting unit; The commutation circuit further comprises: a bypass switch connected in parallel with the AC terminal of the submodule; A modularized batch energy harvesting commutation circuit comprising: a discharge branch circuit connected in parallel with the commutation circuit and including a resonant circuit consisting of a discharge switch connected in series with the commutation circuit and a discharge resistor and / or an inductance and / or an inductance capacitance.

2. The sub-module power units in the commutation circuit are all half-bridge circuits, or all full-bridge circuits, or a mixed arrangement of full-bridge circuits and half-bridge circuits; the half-bridge circuit includes an upper tube and a lower tube, the upper tube is connected in series with the lower tube, and then connected in parallel with the capacitance unit, the collector and the emitter of the upper tube or the lower tube are pulled out to serve as AC terminals of the submodule; The full bridge circuit includes two upper tubes and two lower tubes, and the upper tubes and the lower tubes are connected in series to form a bridge arm, which is then connected in parallel to the capacitance unit, and the midpoint of the bridge arm is pulled out to serve as the AC output terminal of the submodule; 2. The commutation circuit of claim 1, wherein the upper and lower tubes are fully controlled power semiconductor devices or parallel connections of such devices.

3. The connection network includes a parallel connection network or a series connection network; The parallel connection network includes N diode units, the anodes of the N diode units are connected as input terminals of the connection network, and the cathodes of the N diode units are sequentially drawn out to become N output terminals of the connection network; The series connection network includes: A method 1 including N diode units, the N diode units being connected in series in the same direction, the anode of the first diode unit being the input terminal of the connection network, and the cathode of the Nth diode unit being successively pulled out to be the output terminal of the connection network; and a second method including the steps of: (a) including N-1 diode units, the N-1 diode units being connected in series in the same direction; (b) an anode of a first diode unit being an input terminal of the connection network; and (c) an anode of the first diode and a cathode of the N-1th diode unit being successively pulled out to be an output terminal of the connection network; 2. The commutation circuit according to claim 1, wherein the diode unit includes a diode or a diode and a resistor and / or an inductor connected in series.

4. 2. The commutation circuit of claim 1, wherein the first submodule is the submodule with the lowest potential in the commutation circuit.

5. A control method based on the current circuit according to any one of claims 1 to 4, comprising: a batch sub-module pre-functional test in which the first energy harvesting power source is started, the discharge switch is closed, and the capacitance unit of the sub-module is charged by the connection network and the discharge resistor; a batch sub-module sequential pressure test, in which the first energy harvesting power source is started, and a sub-module control unit controls the sub-module to sequentially output a zero voltage level state, sequentially charge the capacitance units of the sub-module, and perform a sub-module function test; a batch sub-module rapid discharge test, in which after the batch sub-module preliminary function test or the batch sub-module sequential pressure test is completed, the first energy acquisition power source is opened, the discharge switch is closed, and the sub-module control unit sequentially turns on the power semiconductor devices at the corresponding positions in the power unit, so that the capacitance units of the sub-modules are sequentially discharged; The method for controlling a commutation circuit, comprising a combination of one or more steps with a batch sub-module discharge bypass test in which, after the batch sub-module rapid discharge test is completed, the capacitance unit of the sub-module is discharged to a fixed value and the bypass switch of the sub-module is automatically closed.

6. The batch sub-module sequential pressure test includes: starting up the first energy harvesting power source and charging the capacitance unit of the connected sub-module; powering the sub-module control unit after a charge threshold is reached; Controlling the power semiconductor device at the corresponding position in the power unit by the sub-module control unit to conduct to a zero voltage level state of the power unit, thereby establishing a conduction circuit for the capacitance unit of the adjacent sub-module; the capacitance unit of the first energy harvesting power source / front end sub-module charges the capacitance unit of the adjacent sub-module and charges the sub-module control unit of the adjacent sub-module; 6. The control method according to claim 5, further comprising: completing the charging of the capacitance units of all the sub-modules in sequence, and charging the N sub-module control units.

7. In a half-bridge circuit, the zero voltage level state is defined as a state in which the lower tube of the power semiconductor device is conductive; 6. The control method according to claim 5, wherein in a full bridge circuit, the zero voltage level state is defined as two upper tubes of the power semiconductor device being conductive at the same time or two lower tubes of the power semiconductor device being conductive at the same time.

8. A high voltage operation circuit, A modular batch energy harvesting commutation circuit according to any one of claims 1 to 3 and a second commutation circuit, The second commutation circuit includes M sub-modules, and AC terminals of the M sub-modules are connected in series, where M is an integer equal to or greater than 2; or includes the batch energy harvesting commutation circuit according to any one of claims 1 to 3; AC terminals of a first sub-module and a last sub-module of the second commutation circuit are pulled out to serve as AC terminals of the second commutation circuit; A high-voltage operation circuit, characterized in that one AC terminal of the batch energy acquisition commutation circuit and one AC terminal of the second commutation circuit are connected via a connecting reactor, and the other AC terminal is short-circuited.

9. A control method based on the high voltage operation circuit according to claim 8, comprising: A cascade charging control in which the first energy acquisition power source and the connection network are used to charge the capacity units of all the sub-modules, and the sub-module control unit operates by taking electricity from the capacity units; and after the cascade charging control is completed, the batch energy capture commutation circuit and the second commutation circuit control a voltage and a current, and the first energy capture power source supplements the batch energy capture commutation circuit and the second commutation circuit with lost energy (cascade operation control).

10. A flexible DC commutation station low voltage pressurization system, the flexible DC commutation station including a flexible DC commutation valve and a valve controller; The flexible DC commutation valve includes three parallel phase bridge arms, each of which is a series connection of an upper bridge arm and a lower bridge arm, and the positive end of the upper bridge arm is connected to a DC positive electrode, the negative end of the upper bridge arm is connected to a positive end of the lower bridge arm, and the negative end of the lower bridge arm is connected to a DC negative electrode; According to the grounding manner of the flexible DC rectifier valve, the corresponding upper bridge arm or lower bridge arm or phase bridge arm is arranged as a batch energy capture rectifier circuit according to any one of claims 1 to 4, and the other bridge arms are arranged as a sub-module series rectifier circuit; The valve controller communicates with a sub-module control unit that controls the operation of the sub-modules.

11. The correspondence between the arrangement method and the grounding method is as follows: The DC negative pole of the flexible DC commutation valve is grounded, and at least one lower bridge arm or a phase bridge arm is arranged as a batch energy harvesting commutation circuit; The DC positive pole of the flexible DC rectifier valve is grounded, the first energy harvesting power source is isolated from the capacitance unit through an isolation module, and an upper bridge arm or a lower bridge arm or a phase bridge arm is arranged as a batch energy harvesting rectifier circuit; When the absolute values ​​of the DC positive pole and the DC negative pole of the flexible DC commutation valve to ground are equal or close to each other, the upper bridge arm or the phase bridge arm is arranged as a batch energy harvesting commutation circuit; The flexible DC commutation station low-voltage pressurization system according to claim 10, characterized in that: the flexible DC commutation valve is not grounded, or is grounded through a grounding switch and the grounding switch is cut off, and the upper bridge arm or the lower bridge arm or the phase bridge arm is arranged as a batch energy recovery commutation circuit.

12. A method for controlling a low-voltage pressurizing system of a flexible DC commutation station according to any one of claims 10 to 11, comprising the steps of: The first energy harvesting power source charges a DC capacitance of the sub-module arranged as a batch energy harvesting commutation circuit, the batch energy harvesting commutation circuit being defined as a charging bridge arm; After the charging of the charging bridge arm is completed, the charging bridge arm starts to operate and outputs a controllable voltage to charge another bridge arm of the flexible DC commutation valve; after the charging of the other bridge arm is completed, the upper bridge arm and the lower bridge arm of any phase are controlled as a voltage source, and a DC voltage is applied equally to the DC positive electrode and the DC negative electrode, which is defined as a pressurizing process.

13. Further, a first high-voltage switch is connected in series with the first energy harvesting power source, and after the charging of the three-phase bridge arm is completed, the first high-voltage switch is cut off and the three-phase bridge arm is unlocked, and the DC positive pole and the DC negative pole present a DC voltage, and the midpoint of the three-phase bridge arm presents a three-phase AC voltage; and / or performing a voltage test and / or sampling calibration on the DC, AC equipment or AC / DC lines during the pressurization process; 13. The control method of claim 12, further comprising: using fast overcurrent protection of the bridge arm and / or short circuit protection of the power semiconductor device to ensure the safety of the equipment when a dielectric breakdown fault occurs during the pressurization process.

14. A field test method for a diverter valve, the diverter valve including six bridge arms and a valve control unit, the bridge arms including the diverter circuit according to any one of claims 1 to 4, the diverter circuit including N sub-modules, the sub-modules being connected to the valve control unit by optical fibers, the field test method comprising: The N output terminals of the connection network are connected to the positive electrodes of the capacitance units of the N submodules; starting up the first energy harvesting power source; The valve control unit identifies whether its physical location matches that of the sub-module with which communication has been established; and acquiring batch energy, and the sub-module performing a function test or the valve control unit updating a program.

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