Phase unit, active phase commutated converter and control method and device and system thereof

Abstract

The application provides a phase unit, an active commutation converter and a control method and device thereof and a system, and relates to the technical field of high-voltage direct current transmission.The phase unit comprises a main branch, an auxiliary branch, a main bridge arm circuit and a lower bridge arm circuit.The main bridge arm circuit and the lower bridge arm circuit are connected in series, one end of the main bridge arm circuit is connected with a main branch anode bus, and one end of the lower bridge arm circuit is connected with a main branch cathode bus.The auxiliary branch comprises an upper bridge transfer circuit, a lower bridge transfer circuit and a main turn-off circuit, one end of the upper bridge transfer circuit is connected with the main bridge arm circuit, the other end of the upper bridge transfer circuit is connected with one end of the lower bridge transfer circuit and one end of the main turn-off circuit, the other end of the lower bridge transfer circuit is connected with the lower bridge arm circuit, and the other end of the main turn-off circuit is connected with a common point of the main bridge arm circuit and the lower bridge arm circuit connected in series.The application can inhibit the occurrence of commutation failure of a high-voltage direct current transmission system and improve the reliability of the high-voltage direct current transmission system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-voltage direct current transmission, in particular to a phase unit, an active commutation converter and a control method and device thereof and a system. BACKGROUND

[0002] With the development of economy and the continuous improvement of technology, the high-voltage and ultra-high-voltage direct current transmission systems connected to the power grid are gradually increasing, but it also increases the hidden danger of safe operation of the power grid. For example, in the case of simultaneous commutation failure of multiple direct currents in a multi-infeed direct current system, there is a threat to the safe operation of the corresponding regional alternating current grid, and with the increasing proportion of new energy power generation in recent years, higher requirements are put forward for the stable operation of the direct current transmission system and the ability to suppress commutation failure.

[0003] The existing direct current transmission technology mainly uses a twelve-pulse circuit structure grid commutation converter and a modular multi-level circuit structure voltage source converter for high-voltage and ultra-high-voltage direct current transmission. In the twelve-pulse circuit structure grid commutation converter, two three-phase six-bridge arm bridge circuits are connected in series or parallel in each twelve-pulse circuit, and a single large-capacity thyristor is used in each bridge arm. In the modular multi-level circuit structure voltage source converter, the modular multi-level circuit is a three-phase six-bridge arm bridge circuit, and a half-bridge sub-module structure or / and a full-bridge sub-module structure is used in series in each bridge arm. In addition, replacing or adding auxiliary turn-off circuits to the existing grid commutation converter to form a controllable turn-off grid commutation converter to solve the commutation failure problem has also become an important direction of direct current transmission technology research.

[0004] However, the existing twelve-pulse circuit structure grid commutation converter has the problem of commutation failure; the existing modular multi-level circuit structure voltage source converter has the problems of small device capacity, high cost and large loss; the existing controllable turn-off grid commutation converter that uses full-controlled devices to replace to suppress commutation failure has small device capacity and reliability needs to be verified; the existing controllable turn-off grid commutation converter that adds auxiliary circuits to suppress commutation failure has a complex structure and reduced reliability; both of the above two controllable turn-off grid commutation converters rely on arresters to absorb energy when forced to turn off, and each bridge arm needs to be equipped with an equal amount of arresters. In the case of single-phase grounding and other faults with a high probability, only the arresters of the faulty phase will act, resulting in low utilization of the arresters. Since the arresters can only absorb energy for a short time, the arresters cannot act in steady-state operation, so the grid commutation voltage still needs to be relied on for commutation, which makes it impossible to control the minimum turn-off angle too small, and still consumes a lot of reactive power. SUMMARY

[0005] In order to inhibit the occurrence of commutation failure of a high-voltage direct current transmission system, reduce the cost of a controllable turn-off grid commutated converter, improve the reliability of the high-voltage direct current transmission system, and reduce the turn-off angle reference value and consumed reactive power in the commutation process of the grid commutated converter, the application provides a phase unit, an active commutation converter and a control method and device thereof and a system.

[0006] The application provides a phase unit, which adopts the following technical scheme:

[0007] The application provides a phase unit, which adopts the following technical scheme:

[0008] The main branch circuit comprises an upper bridge arm circuit and a lower bridge arm circuit, wherein the upper bridge arm circuit and the lower bridge arm circuit are connected in series, one end of the upper bridge arm circuit is connected with a main branch circuit anode bus, and one end of the lower bridge arm circuit is connected with a main branch circuit cathode bus.

[0009] The auxiliary branch circuit comprises an upper bridge transfer circuit, a lower bridge transfer circuit and a main turn-off circuit, wherein one end of the upper bridge transfer circuit is connected with the upper bridge arm circuit, the other end of the upper bridge transfer circuit is connected with one end of the lower bridge transfer circuit and one end of the main turn-off circuit, the other end of the lower bridge transfer circuit is connected with the lower bridge arm circuit, and the other end of the main turn-off circuit is connected with a common point of the upper bridge arm circuit and the lower bridge arm circuit connected in series.

[0010] According to some embodiments, the upper bridge arm circuit and the lower bridge arm circuit respectively comprise a first half-controlled valve and / or a first fully-controlled valve; or the upper bridge arm circuit and the lower bridge arm circuit respectively comprise a first half-controlled valve and / or a first fully-controlled valve and a second half-controlled valve; the upper bridge transfer circuit and the lower bridge transfer circuit respectively comprise a third half-controlled valve and / or a second fully-controlled valve; and the main turn-off circuit comprises a third fully-controlled valve.

[0011] According to some embodiments, in the case that the upper bridge arm circuit and the lower bridge arm circuit respectively comprise a second half-controlled valve, one end of the first half-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with the main branch circuit anode bus, the other end of the first half-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with one end of the second half-controlled valve and one end of the third half-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit, the other end of the second half-controlled valve of the upper bridge arm circuit is connected with one end of the third fully-controlled valve of the main turn-off circuit, and the other end of the third fully-controlled valve of the main turn-off circuit is connected with the other end of the third half-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit.

[0012] One end of the first semi-controlled valve and / or the first fully-controlled valve of the lower bridge arm circuit is connected with the main branch cathode bus, the other end of the first semi-controlled valve and / or the first fully-controlled valve of the lower bridge arm circuit is connected with one end of the second semi-controlled valve and one end of the third semi-controlled valve and / or the second fully-controlled valve of the lower bridge transfer circuit, the other end of the second semi-controlled valve of the lower bridge arm circuit is connected with one end of the third fully-controlled valve of the main turn-off circuit, the other end of the third fully-controlled valve of the main turn-off circuit is connected with the other end of the third semi-controlled valve and / or the second fully-controlled valve of the lower bridge transfer circuit.

[0013] According to some embodiments, in the case that the upper bridge arm circuit and the lower bridge arm circuit do not respectively include the second semi-controlled valve,

[0014] One end of the first semi-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with the main branch anode bus, the other end of the first semi-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with one end of the third semi-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit and one end of the third fully-controlled valve of the main turn-off circuit, the other end of the third semi-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit is connected with the other end of the third fully-controlled valve of the main turn-off circuit.

[0015] One end of the first semi-controlled valve and / or the first fully-controlled valve of the lower bridge arm circuit is connected with the main branch cathode bus, the other end of the first semi-controlled valve and / or the first fully-controlled valve of the lower bridge arm circuit is connected with one end of the third semi-controlled valve and / or the second fully-controlled valve of the lower bridge transfer circuit and one end of the third fully-controlled valve of the main turn-off circuit, the other end of the third semi-controlled valve and / or the second fully-controlled valve of the lower bridge transfer circuit is connected with the other end of the third fully-controlled valve of the main turn-off circuit.

[0016] According to some embodiments, the first semi-controlled valve and / or the first fully-controlled valve, and / or the second semi-controlled valve, and / or the third semi-controlled valve and / or the second fully-controlled valve, and / or the third fully-controlled valve are connected in parallel with a lightning arrester.

[0017] According to some embodiments, the first semi-controlled valve, the second semi-controlled valve, the third semi-controlled valve comprise at least one of a unidirectional semi-controlled switch, a bidirectional semi-controlled switch; the first fully-controlled valve, the second fully-controlled valve comprise at least one of a unidirectional fully-controlled switch, a bidirectional fully-controlled switch, a sub-module series switch; the third fully-controlled valve comprises at least one of a bidirectional fully-controlled switch, a sub-module series switch.

[0018] According to some embodiments, the unidirectional semi-controlled switch is composed of a series of controllable turn-on but uncontrollable turn-off semiconductor devices, which include but are not limited to thyristors;

[0019] The bidirectional half-controlled switch is composed of controllable turn-on but uncontrollable turn-off semiconductor devices connected in anti-parallel and then connected in series, and the controllable turn-on but uncontrollable turn-off semiconductor devices include but are not limited to thyristors.

[0020] The unidirectional fully-controlled switch is composed of semiconductor devices with unidirectional turn-off capability connected in series, and the semiconductor devices with unidirectional turn-off capability include but are not limited to insulated gate bipolar transistors and integrated gate-commutated thyristors.

[0021] The bidirectional fully-controlled switch is composed of semiconductor devices with bidirectional turn-off capability connected in series, and the semiconductor devices with bidirectional turn-off capability include but are not limited to anti-parallel reverse blocking integrated gate-commutated thyristors and series-connected insulated gate bipolar transistor modules.

[0022] The submodule series switch is composed of submodules connected in series, and the submodules include but are not limited to half-bridge submodules, full-bridge submodules, quasi-full-bridge submodules and clamped double submodules, and the switching devices of the half-bridge submodules, full-bridge submodules, quasi-full-bridge submodules or clamped double submodules include but are not limited to insulated gate bipolar transistors and integrated gate-commutated thyristors.

[0023] According to some embodiments, the main turn-off circuit further includes a fourth half-controlled valve connected in parallel with the third fully-controlled valve, and the fourth half-controlled valve includes at least one of the unidirectional half-controlled switch and the bidirectional half-controlled switch.

[0024] The application provides an active commutation converter, which adopts the following technical scheme:

[0025] The active commutation converter includes at least one phase unit; or,

[0026] The active commutation converter includes at least one phase unit and an auxiliary turn-off circuit; or,

[0027] The active commutation converter includes at least one main branch, at least one auxiliary branch, a main turn-off circuit of the at least one main branch and a main turn-off circuit of the at least one auxiliary branch; one end of the main turn-off circuit of the at least one auxiliary branch is connected to a phase output end, the other end of the main turn-off circuit of the at least one auxiliary branch is connected to a common point at which upper arm circuits and lower arm circuits of the at least one main branch are connected in series, and the upper arm circuits and the lower arm circuits of the at least one main branch each include a first fully-controlled valve; or,

[0028] The active commutation converter includes at least one main branch, at least one auxiliary branch, a main turn-off circuit of the at least one main branch, a main turn-off circuit of the at least one auxiliary branch and an auxiliary turn-off circuit; one end of the main turn-off circuit of the at least one auxiliary branch is connected to a phase output end, and the other end of the main turn-off circuit of the at least one auxiliary branch is connected to a common point at which upper arm circuits and lower arm circuits of the at least one main branch are connected in series.

[0029] The auxiliary turn-off circuit is connected in parallel with the upper bridge arm circuit or the lower bridge arm circuit of at least one of the main branches and the circuit constructed by the main turn-off circuit of at least one of the auxiliary branches; or the auxiliary turn-off circuit is connected in parallel with the at least one phase unit.

[0030] According to some embodiments, the main branch anode bus is a positive input end, one end of the main turn-off circuit of the auxiliary branch is a phase output end, and the main branch cathode bus is a negative input end.

[0031] According to some embodiments, one end of the auxiliary turn-off circuit is connected with the main branch anode bus of the main current commutated converter, and the other end of the auxiliary turn-off circuit is connected with the main branch cathode bus of the main current commutated converter.

[0032] According to some embodiments, the auxiliary turn-off circuit and the main branch anode bus and the main branch cathode bus of the main current commutated converter are connected through a disconnector or / and a knife switch.

[0033] According to some embodiments, in the case that the circuit constructed by the auxiliary turn-off circuit is connected in parallel with the upper bridge arm circuit or the lower bridge arm circuit of at least one of the main branches and the circuit constructed by the main turn-off circuit of at least one of the auxiliary branches, the auxiliary turn-off circuit comprises a fourth fully controlled valve; or the auxiliary turn-off circuit comprises a fourth fully controlled valve and a fifth semi-controlled valve; the fourth fully controlled valve and the fifth semi-controlled valve are connected in series; or,

[0034] In the case that the auxiliary turn-off circuit is connected in parallel with the at least one phase unit, the auxiliary turn-off circuit comprises a fifth fully controlled valve; or the auxiliary turn-off circuit comprises a fifth fully controlled valve and a sixth semi-controlled valve; the fifth fully controlled valve and the sixth semi-controlled valve are connected in series.

[0035] According to some embodiments, in the case that the circuit constructed by the auxiliary turn-off circuit is connected in parallel with the upper bridge arm circuit or the lower bridge arm circuit of at least one of the main branches and the circuit constructed by the main turn-off circuit of at least one of the auxiliary branches, the auxiliary turn-off circuit further comprises a seventh semi-controlled valve or a first non-controlled valve; the seventh semi-controlled valve or the first non-controlled valve, the fourth fully controlled valve and the fifth semi-controlled valve are connected in series, and the circuit connected in series is connected in parallel with the upper bridge arm circuit or the lower bridge arm circuit, or the circuit connected in series is connected in parallel with the upper bridge arm circuit or the lower bridge arm circuit and the circuit connected in series with the main turn-off circuit of at least one of the auxiliary branches.

[0036] According to some embodiments, in the case that the auxiliary turn-off circuit is connected in parallel with the at least one phase unit, the first semi-controlled valve and the second semi-controlled valve comprise bidirectional semi-controlled switches.

[0037] According to some embodiments, in the case that the circuit constructed by the auxiliary turn-off circuit is connected in parallel with the upper bridge arm circuit or the lower bridge arm circuit of at least one of the main branches and the circuit constructed by the main turn-off circuit of at least one of the auxiliary branches, the upper bridge arm circuit and / or the lower bridge arm circuit share the fourth fully-controlled valve and / or the fifth semi-controlled valve of the auxiliary turn-off circuit.

[0038] In the case that the auxiliary turn-off circuit is connected in parallel with the at least one phase unit, the upper bridge arm circuit and the lower bridge arm circuit share the fifth fully-controlled valve and / or the sixth semi-controlled valve of the auxiliary turn-off circuit.

[0039] According to some embodiments, the fifth semi-controlled valve and the sixth semi-controlled valve comprise unidirectional semi-controlled switches, the fourth fully-controlled valve and the fifth fully-controlled valve comprise at least one of unidirectional fully-controlled switches, bidirectional fully-controlled switches and submodule series switches, and the first non-controlled valve comprises non-controlled switches; the non-controlled switches are composed of series-connected non-controlled turn-on and turn-off semiconductor devices, and the non-controlled turn-on and turn-off semiconductor devices include but are not limited to diodes.

[0040] According to some embodiments, the fifth semi-controlled valve, and / or the fourth fully-controlled valve, and / or the fifth fully-controlled valve, and / or the sixth semi-controlled valve are connected in parallel with lightning arresters.

[0041] The application provides an active phase commutation converter control method, which adopts the following technical scheme:

[0042] An active phase commutation converter control method, characterized by being used for controlling the active phase commutation converter, and comprising the following steps of:

[0043] In the case that the operation parameter information of the active phase commutation converter is acquired, inverse variable state control information is generated based on the parameter information, and the main branch of the bridge arm circuit is controlled to operate in an inverse variable state based on the inverse variable state control information.

[0044] In the case that the active commutation converter comprises at least one phase unit and / or auxiliary blocking circuit, and the obtained commutation angle reference value of the active commutation converter is less than the minimum blocking angle constant value or commutation failure information, a first circuit conduction instruction and first negative voltage control information are generated, and the transfer circuit in the auxiliary branch corresponding to the commutation bridge arm is controlled to be conducted based on the first circuit conduction instruction, and the main blocking circuit of the auxiliary branch corresponding to the commutation bridge arm is controlled to present negative voltage based on the first negative voltage control information; in the case that the second half-controlled valve of the commutation bridge arm of the main branch recovers blocking, a first circuit blocking instruction is generated, and the main blocking circuit of the auxiliary branch is controlled to be blocked; or, in the case that the active commutation converter comprises the main branch and the main blocking circuit of the auxiliary branch, and the obtained commutation angle reference value is less than the minimum blocking angle constant value or commutation failure information, a first circuit blocking instruction is generated, and the main blocking circuit of the auxiliary branch is controlled to be blocked.

[0045] According to some embodiments, in the case that the active commutation converter is in normal operation, the commutation angle reference value is set to be less than the minimum blocking angle constant value; in the case that the obtained commutation angle reference value is less than the minimum blocking angle constant value, and the second half-controlled valve of the commutation bridge arm of the main branch recovers blocking, a first circuit blocking instruction is generated, and the third fully-controlled valve corresponding to the commutation bridge arm is controlled to be blocked.

[0046] According to some embodiments, before the main blocking circuit of the auxiliary branch is controlled to be blocked, second negative voltage control information is generated, and the main blocking circuit of the auxiliary branch corresponding to the commutation bridge arm is controlled to present negative voltage based on the second negative voltage control information.

[0047] According to some embodiments, in the case that the capacitor voltage of the sub-module of the third fully-controlled valve of the main blocking circuit is less than the rated value and exceeds a first threshold value, and the second half-controlled valve of the commutation bridge arm of the main branch recovers blocking, a first circuit blocking instruction is generated in advance; or / and the number of sub-modules of the third fully-controlled valve of the main blocking circuit is increased; or / and a first circuit conduction instruction and first negative voltage control information are generated in advance; the first threshold value ranges from 0.01 to 0.6 times the rated capacitor voltage.

[0048] According to some embodiments, in the case that the capacitor voltage of the sub-module of the third fully-controlled valve of the main blocking circuit is greater than or equal to the rated value and exceeds a second threshold value, and the first half-controlled valve of the commutation bridge arm of the main branch recovers blocking, a first circuit blocking instruction is generated later; or / and the number of sub-modules of the third fully-controlled valve of the main blocking circuit is reduced; or / and a first circuit conduction instruction and first negative voltage control information are generated later; the second threshold value ranges from 0.01 to 0.6 times the rated capacitor voltage.

[0049] According to some embodiments, the control of the main turn-off circuit presenting negative voltage is achieved by controlling the switch device in the third fully controlled valve sub-module to be turned on so that the sub-module presents capacitive negative voltage in the current flow direction.

[0050] According to some embodiments, the recovery turn-off of the second semi-controlled valve of the phase-changing bridge arm of the main branch is determined according to the reverse recovery time of the second semi-controlled valve, which is greater than or equal to the reverse recovery time of the thyristor contained in the second semi-controlled valve.

[0051] According to some embodiments, in the case of overvoltage or failure of the third fully controlled valve, the second semi-controlled valve or the fourth semi-controlled valve of the same phase unit of the third fully controlled valve is controlled to be turned on.

[0052] According to some embodiments, the method further comprises:

[0053] In the case that the upper bridge arm circuit and the lower bridge arm circuit each comprise a first fully controlled valve, the phase-changing failure information is obtained, and the main turn-off circuit cannot provide sufficient phase-changing voltage, a second circuit turn-off instruction is generated, and the first fully controlled valve is controlled to be turned off based on the second circuit turn-off instruction.

[0054] According to some embodiments, in the case that the upper bridge transfer circuit and the lower bridge transfer circuit each comprise a second fully controlled valve, the method further comprises:

[0055] In the case that the phase-changing failure information is obtained and the main turn-off circuit cannot provide sufficient phase-changing voltage, a third circuit turn-off instruction is generated, and the second fully controlled valve is controlled to be turned off based on the third circuit turn-off instruction.

[0056] According to some embodiments, in the case that the main phase-changing current converter further comprises an auxiliary turn-off circuit, the method further comprises:

[0057] In the case that the phase-changing failure information is obtained and the main turn-off circuit cannot provide sufficient phase-changing voltage, a second circuit turn-on instruction is generated, and the corresponding auxiliary turn-off circuit of the phase-changing bridge arm is controlled to be turned on based on the second circuit turn-on instruction; in the case that the first semi-controlled valve and / or the second semi-controlled valve of the phase-changing bridge arm of the main branch is recovered to be turned off, a fourth circuit turn-off instruction is generated, and the auxiliary turn-off circuit is controlled to be turned off.

[0058] According to some embodiments, the main phase-changing current converter adopts a network construction control method to control voltage and frequency.

[0059] According to some embodiments, in the case that the main phase-changing current converter further comprises an auxiliary turn-off circuit, the auxiliary turn-off circuit and the main anode bus and the main cathode bus of the main branch of the main forced phase-changing current converter are connected through a disconnector or / and a knife switch, and in the case of failure of the auxiliary turn-off circuit, the disconnector and / or the knife switch is disconnected.

[0060] The application provides an active commutation converter control device, which adopts the technical scheme as follows:

[0061] An active commutation converter control device for controlling the active commutation converter, comprising:

[0062] A first control module for generating inverter state control information based on the parameter information and controlling the main branch to operate in an inverter state based on the inverter state control information when the operating parameter information of the active commutation converter is obtained.

[0063] A second control module for generating a first circuit conduction instruction and a first negative voltage control information and controlling the transfer circuit in the auxiliary branch corresponding to the commutation bridge arm to conduct based on the first circuit conduction instruction and controlling the main turn-off circuit of the auxiliary branch corresponding to the commutation bridge arm to present a negative voltage based on the first negative voltage control information when the active commutation converter comprises at least one phase unit and the reference value of the turn-off angle is less than the minimum turn-off angle or the commutation failure information is obtained; generating a first circuit turn-off instruction and controlling the main turn-off circuit of the auxiliary branch to turn off when the second half-controlled valve of the commutation bridge arm of the main branch recovers the turn-off; or generating a first circuit turn-off instruction and controlling the main turn-off circuit of the auxiliary branch to turn off when the active commutation converter comprises the main turn-off circuit of the main branch and the auxiliary branch and the reference value of the turn-off angle is less than the minimum turn-off angle or the commutation failure information is obtained.

[0064] The application provides a high-voltage direct-current power transmission system comprising the active commutation converter.

[0065] According to some embodiments, the high-voltage direct-current power transmission system is a two-terminal direct-current power transmission system or a multi-terminal direct-current power transmission system, which respectively comprises a single-pole direct-current power transmission system, a bipolar direct-current power transmission system or a back-to-back direct-current system.

[0066] According to some embodiments, the converter part of the two-terminal direct-current power transmission system or the multi-terminal direct-current power transmission system that needs to operate in an inverter mode adopts the active commutation converter.

[0067] In summary, the application has the following beneficial technical effects:

[0068] When the reference value of the turn-off angle is small or the commutation failure of the AC system fault is likely to occur, the main turn-off circuit presents negative voltage, the corresponding transfer circuit is turned on to form parallel current with the second half-controlled valve of the main branch commutation bridge arm, the current is transferred to the auxiliary branch, the main turn-off circuit of the auxiliary branch is turned off, and the commutation bridge arm is turned off; if the main turn-off circuit cannot provide sufficient turn-off voltage, the first fully-controlled valve of the main branch is turned off, or the auxiliary turn-off circuit is turned on first, then the first half-controlled valve of the main branch is turned off and the auxiliary turn-off circuit is turned off after the current is transferred and the turn-off is restored, the commutation bridge arm is turned off, the commutation failure of the active commutation converter is effectively suppressed, the active commutation converter is realized controllable turn-off, and the reliability of the high-voltage direct current transmission system is improved; meanwhile, the continuous turn-off capability of the main turn-off circuit can reduce the reference value of the turn-off angle and reduce the consumed reactive power; compared with the prior art, the circuit structure of the application is simple, the reactive power compensation equipment can be reduced, the cost of the high-voltage direct current transmission system with controllable turn-off capability is reduced, and the reliability of the system is improved. BRIEF DESCRIPTION OF DRAWINGS

[0069] Figure 1 is one of the phase unit schematic diagrams of the embodiment of the application;

[0070] Figure 2 is the second phase unit schematic diagram of the embodiment of the application;

[0071] Figure 3A , Figure 3B , Figure 3C , Figure 3D , Figure 3E , Figure 3F , Figure 3G , Figure 3H , Figure 3I , Figure 3J , Figure 3K , Figure 3L and Figure 3M is the valve structure schematic diagram of the embodiment of the application;

[0072] Figure 4 is one of the active commutation converter schematic diagrams of the embodiment of the application;

[0073] Figure 5 is the second active commutation converter schematic diagram of the embodiment of the application;

[0074] Figure 6 is the third active commutation converter schematic diagram of the embodiment of the application;

[0075] Figure 7 is the fourth active commutation converter schematic diagram of the embodiment of the application;

[0076] Figure 8 is the fifth active commutation converter schematic diagram of the embodiment of the application;

[0077] Figure 9 Figure 7 is a schematic diagram of an active commutation converter according to an embodiment of the application;

[0078] Figure 10 Figure 8 is a schematic diagram of an active commutation converter according to an embodiment of the application;

[0079] Figure 11 Figure 9 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0080] Figure 12 Figure 10 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0081] Figure 13 Figure 11 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0082] Figure 14 Figure 12 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0083] Figure 15 Figure 13 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0084] Figure 16 Figure 14 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0085] Figure 17 Figure 15 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0086] Figure 18 Figure 16 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0087] Figure 19 Figure 17 is a circuit diagram of an active commutation converter including valve structures according to an embodiment of the application;

[0088] Figure 20 Figure 18 is a block diagram of a control method for an active commutation converter according to an embodiment of the application;

[0089] Figure 21 Figure 19 is a flow diagram of a control method for an active commutation converter according to an embodiment of the application;

[0090] Figure 22 Figure 20 is a block diagram of a control device for an active commutation converter according to an embodiment of the application;

[0091] Figure 23 Figure 21 is a schematic diagram of a high voltage direct current power transmission system including an active commutation converter according to an embodiment of the application.

[0092] Explanation of reference signs: 1, upper bridge arm circuit; 2, lower bridge arm circuit; 3, upper bridge transfer circuit; 4, lower bridge transfer circuit; 5, main turn-off circuit; 6, first auxiliary turn-off circuit; 7, second auxiliary turn-off circuit; 8, first grid commutated converter; 9, second grid commutated converter; 10, first converter transformer; 11, second converter transformer; 12, first alternating current system; 13, direct current line; 14, first active commutated converter; 15, second active commutated converter; 16, third converter transformer; 17, fourth converter transformer; 18, second alternating current system; 201, first control module; 202, second control module. DETAILED DESCRIPTION

[0093] The following will be combined with the accompanying Figures 1-23 The present application is further described in detail.

[0094] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical scheme in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0095] The embodiments of the present application provide a phase unit, comprising: a main branch and an auxiliary branch, wherein the main branch comprises an upper bridge arm circuit and a lower bridge arm circuit; wherein the upper bridge arm circuit and the lower bridge arm circuit are connected in series, one end of the upper bridge arm circuit is connected with a main branch anode bus, and one end of the lower bridge arm circuit is connected with a main branch cathode bus.

[0096] The auxiliary branch comprises an upper bridge transfer circuit, a lower bridge transfer circuit and a main turn-off circuit; wherein one end of the upper bridge transfer circuit is connected with the upper bridge arm circuit, the other end of the upper bridge transfer circuit is connected with one end of the lower bridge transfer circuit and one end of the main turn-off circuit, the other end of the lower bridge transfer circuit is connected with the lower bridge arm circuit, and the other end of the main turn-off circuit is connected with a common point of the upper bridge arm circuit and the lower bridge arm circuit connected in series.

[0097] The upper bridge arm circuit and the lower bridge arm circuit respectively comprise a first half-controlled valve and / or a first fully-controlled valve; or the upper bridge arm circuit and the lower bridge arm circuit respectively comprise a first half-controlled valve and / or a first fully-controlled valve, a second half-controlled valve; the upper bridge transfer circuit and the lower bridge transfer circuit respectively comprise a third half-controlled valve and / or a second fully-controlled valve; and the main turn-off circuit comprises a third fully-controlled valve.

[0098] In the case that the upper bridge arm circuit and the lower bridge arm circuit respectively comprise the second half-controlled valve, one end of the first half-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with the main branch anode bus, the other end of the first half-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with one end of the second half-controlled valve and one end of the third half-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit, the other end of the second half-controlled valve of the upper bridge arm circuit is connected with one end of the third fully-controlled valve of the main turn-off circuit, the other end of the third fully-controlled valve of the main turn-off circuit is connected with the other end of the third half-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit.

[0099] One end of the first half-controlled valve and / or the first fully-controlled valve of the lower bridge arm circuit is connected with the main branch cathode bus, the other end of the first half-controlled valve and / or the first fully-controlled valve of the lower bridge arm circuit is connected with one end of the second half-controlled valve and one end of the third half-controlled valve and / or the second fully-controlled valve of the lower bridge transfer circuit, the other end of the second half-controlled valve of the lower bridge arm circuit is connected with one end of the third fully-controlled valve of the main turn-off circuit, the other end of the third fully-controlled valve of the main turn-off circuit is connected with the other end of the third half-controlled valve and / or the second fully-controlled valve of the lower bridge transfer circuit.

[0100] Referring to Figure 1 , the main branch comprises: the upper bridge arm circuit 1 and the lower bridge arm circuit 2 connected in series, one end of the upper bridge arm circuit 1 is connected with the main branch anode bus P1, one end of the lower bridge arm circuit 2 is connected with the main branch cathode bus N1.

[0101] The auxiliary branch comprises: the upper bridge transfer circuit 3, the lower bridge transfer circuit 4 and the main turn-off circuit 5, one end of the upper bridge transfer circuit 3 is connected with the upper bridge arm circuit 1, the other end of the upper bridge transfer circuit 3 is connected with one end of the lower bridge transfer circuit 4 and one end of the main turn-off circuit 5, the other end of the lower bridge transfer circuit 4 is connected with the lower bridge arm circuit 2, the other end of the main turn-off circuit 5 is connected with the common point of the upper bridge arm circuit 1 and the lower bridge arm circuit 2 connected in series.

[0102] In some embodiments, referring to Figure 1 , the upper bridge arm circuit 1 comprises the first half-controlled valve and / or the first fully-controlled valve V41, the second half-controlled valve V42; the lower bridge arm circuit 2 comprises the first half-controlled valve and / or the first fully-controlled valve V11, the second half-controlled valve V12; the upper bridge transfer circuit 3 comprises the third half-controlled valve and / or the second fully-controlled valve V43; the lower bridge transfer circuit 4 comprises the third half-controlled valve and / or the second fully-controlled valve V13; the main turn-off circuit comprises the third fully-controlled valve V410.

[0103] One end of the first half-controlled valve and / or the first fully-controlled valve V41 of the upper bridge arm circuit 1 is connected with the main branch anode bus P1, and the other end of the first half-controlled valve and / or the first fully-controlled valve V41 of the upper bridge arm circuit 1 is connected with one end of the second half-controlled valve V42 and one end of the third half-controlled valve and / or the second fully-controlled valve V43 of the upper bridge transfer circuit 3; the other end of the second half-controlled valve V42 of the upper bridge arm circuit 1 is connected with one end of the third fully-controlled valve V410 of the main turn-off circuit 5 and one end of the second half-controlled valve V12 of the lower bridge arm circuit 2, and serves as a phase output end; the other end of the third half-controlled valve and / or the second fully-controlled valve V43 of the upper bridge transfer circuit 3 is connected with the other end of the third fully-controlled valve V410 of the main turn-off circuit 5.

[0104] One end of the first half-controlled valve and / or the first fully-controlled valve V11 of the lower bridge arm circuit 2 is connected with the main branch cathode bus N1, and the other end of the first half-controlled valve and / or the first fully-controlled valve V11 of the lower bridge arm circuit 2 is connected with one end of the second half-controlled valve V12 and one end of the third half-controlled valve and / or the second fully-controlled valve V13 of the lower bridge transfer circuit 4; the other end of the second half-controlled valve V12 of the lower bridge arm circuit 2 is connected with one end of the second half-controlled valve V42 of the upper bridge arm circuit 1 and one end of the third fully-controlled valve V410 of the main turn-off circuit 5, and serves as a phase output end; the other end of the third half-controlled valve and / or the second fully-controlled valve V13 of the lower bridge transfer circuit 4 is connected with one end of the third half-controlled valve and / or the second fully-controlled valve V43 of the upper bridge transfer circuit 3 and the other end of the third fully-controlled valve V410 of the main turn-off circuit 5.

[0105] In some embodiments, in the case that the upper bridge arm circuit and the lower bridge arm circuit do not respectively include the second half-controlled valve, one end of the first half-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with the main branch anode bus, the other end of the first half-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with one end of the third half-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit and one end of the third fully-controlled valve of the main turn-off circuit, and the other end of the third half-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit is connected with the other end of the third fully-controlled valve of the main turn-off circuit.

[0106] In some embodiments, in the case that the upper bridge arm circuit and the lower bridge arm circuit do not respectively include the second half-controlled valve, one end of the first half-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with the main branch anode bus, the other end of the first half-controlled valve and / or the first fully-controlled valve of the upper bridge arm circuit is connected with one end of the third half-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit and one end of the third fully-controlled valve of the main turn-off circuit, and the other end of the third half-controlled valve and / or the second fully-controlled valve of the upper bridge transfer circuit is connected with the other end of the third fully-controlled valve of the main turn-off circuit.

[0107] In some embodiments, with reference to Figure 2The upper bridge arm circuit 1 includes a first semi-controlled valve and / or a first fully-controlled valve V41; the lower bridge arm circuit 2 includes a first semi-controlled valve and / or a first fully-controlled valve V11; the upper bridge transfer circuit 3 includes a third semi-controlled valve and / or a second fully-controlled valve V43; the lower bridge transfer circuit 4 includes a third semi-controlled valve and / or a second fully-controlled valve V13; and the main turn-off circuit includes a third fully-controlled valve V410.

[0108] One end of the first semi-controlled valve and / or the first fully-controlled valve V41 of the upper bridge arm circuit 1 is connected with the main branch anode bus P1, and the other end of the first semi-controlled valve and / or the first fully-controlled valve V41 of the upper bridge arm circuit 1 is connected with one end of the third fully-controlled valve V410 of the main turn-off circuit 5, one end of the third semi-controlled valve and / or the second fully-controlled valve V43 of the upper bridge transfer circuit 3, and one end of the first semi-controlled valve and / or the first fully-controlled valve V11 of the lower bridge arm circuit 2; the other end of the third fully-controlled valve V410 of the main turn-off circuit 5 is connected with the other end of the third semi-controlled valve and / or the second fully-controlled valve V43 of the upper bridge transfer circuit 3 and one end of the third semi-controlled valve and / or the second fully-controlled valve V13 of the lower bridge transfer circuit 4, and serves as a phase output end.

[0109] One end of the first semi-controlled valve and / or the first fully-controlled valve V11 of the lower bridge arm circuit 2 is connected with the main branch cathode bus N1, and the other end of the first semi-controlled valve and / or the first fully-controlled valve V11 of the lower bridge arm circuit 2 is connected with one end of the first semi-controlled valve and / or the first fully-controlled valve V41 of the upper bridge arm circuit 1, one end of the third semi-controlled valve and / or the second fully-controlled valve V13 of the lower bridge transfer circuit 4, and one end of the third fully-controlled valve V410 of the main turn-off circuit 5; the other end of the third semi-controlled valve and / or the second fully-controlled valve V13 of the lower bridge transfer circuit 4 is connected with one end of the third semi-controlled valve and / or the second fully-controlled valve V43 of the upper bridge transfer circuit 3 and the other end of the third fully-controlled valve V410 of the main turn-off circuit 5, and serves as a phase output end.

[0110] The third semi-controlled valve and / or the second fully-controlled valve V43 of the upper bridge transfer circuit 3 and the third semi-controlled valve and / or the second fully-controlled valve V13 of the lower bridge transfer circuit 4 are in parallel connection, and can be integrated into one valve, and a bidirectional semi-controlled switch or a bidirectional fully-controlled switch is used.

[0111] Figure 2 The circuit shown is compared with Figure 1 Compared with the circuit shown, the first semi-controlled valve and / or the first fully-controlled valve V41 of the upper bridge arm circuit 1 and the first semi-controlled valve and / or the first fully-controlled valve V11 of the lower bridge arm circuit 2 need to bear the voltage of the entire bridge arm, and the efficiency of the converter will be reduced.

[0112] In some embodiments, the main turn-off circuit further includes a fourth semi-controlled valve, and the fourth semi-controlled valve and the third fully-controlled valve are connected in parallel.

[0113] In some embodiments, the first half-controlled valve, the second half-controlled valve, the third half-controlled valve, and the fourth half-controlled valve respectively comprise at least one of a unidirectional half-controlled switch and a bidirectional half-controlled switch, the first fully-controlled valve and the second fully-controlled valve respectively comprise at least one of a unidirectional fully-controlled switch, a bidirectional fully-controlled switch, and a sub-module series switch, and the third fully-controlled valve comprises at least one of a bidirectional fully-controlled switch and a sub-module series switch.

[0114] In some embodiments, the unidirectional half-controlled switch is composed of controllable turn-on but uncontrollable turn-off semiconductor devices in series, the controllable turn-on but uncontrollable turn-off semiconductor devices include but are not limited to thyristors; the bidirectional half-controlled switch is composed of controllable turn-on but uncontrollable turn-off semiconductor devices in anti-parallel connection and then in series, the controllable turn-on but uncontrollable turn-off semiconductor devices include but are not limited to thyristors; the unidirectional fully-controlled switch is composed of switch devices with unidirectional turn-off capability in series, the switch devices with unidirectional turn-off capability include but are not limited to insulated gate bipolar transistors and integrated gate-commutated thyristors; the bidirectional fully-controlled switch is composed of switch devices with bidirectional turn-off capability in series, the switch devices with bidirectional turn-off capability include but are not limited to anti-parallel integrated gate-commutated thyristors and reverse series insulated gate bipolar transistor modules; and the sub-module series switch is composed of sub-modules in series, the sub-modules include but are not limited to half-bridge sub-modules, full-bridge sub-modules, full-bridge-like sub-modules, or clamped double sub-modules, and the switch devices of the half-bridge sub-modules, the full-bridge sub-modules, the full-bridge-like sub-modules, or the clamped double sub-modules include but are not limited to insulated gate bipolar transistors and integrated gate-commutated thyristors.

[0115] In some embodiments, the fully-controlled switch comprises at least one fully-controlled device in series, the fully-controlled device comprises at least one of an integrated gate commutated thyristor (IGCT), a reverse blocking IGCT, an insulated gate bipolar transistor (IGBT), a gate turn-off thyristor (GTO), and a metal oxide semiconductor field effect transistor (MOSFET); the half-controlled switch comprises at least one half-controlled device in series, the half-controlled device comprises a thyristor; and the non-controlled switch comprises at least one non-controlled device in series, the non-controlled device comprises a diode.

[0116] In some embodiments, referring to Figure 3A the non-controlled switch comprises a diode D1 in series, which cannot be controlled to turn on and turn off, has unidirectional current flow capability and unidirectional blocking voltage capability; and referring to Figure 3B, the unidirectional half-controlled switch comprises a thyristor T1 connected in series, which only controls turn-on and cannot control turn-off, has unidirectional current flow capability and bidirectional blocking voltage capability, and optionally, the unidirectional half-controlled switch is composed of a thyristor and a diode connected in series; refer to Figure 3C , the bidirectional half-controlled switch is composed of a thyristor T1 connected in anti-parallel series, which only controls turn-on and cannot control turn-off, has bidirectional current flow capability and bidirectional blocking voltage capability; refer to Figure 3D , the anti-parallel uncontrolled switch and the unidirectional half-controlled switch are composed of a thyristor T1 and a diode D1 connected in anti-parallel series, which only controls turn-on in one direction and cannot control turn-off, has bidirectional current flow capability and unidirectional blocking voltage capability; refer to Figure 3E , the unidirectional full-controlled switch comprises an IGBT module connected in series, the IGBT module comprises an IGBT (T2) and a diode D2 connected in anti-parallel therewith, which only controls turn-on and turn-off in one direction, has bidirectional current flow capability and unidirectional blocking voltage capability; refer to Figure 3F , the unidirectional full-controlled switch comprises an inverse blocking type IGCT (T3) connected in series, which only controls turn-on and turn-off in one direction, has unidirectional current flow capability and bidirectional blocking voltage capability; refer to Figure 3G , the unidirectional full-controlled switch comprises an IGBT module and a diode D1 connected in series, which only controls turn-on and turn-off in one direction, has unidirectional current flow capability and bidirectional blocking voltage capability; refer to Figure 3H , the unidirectional full-controlled switch comprises an inverse blocking type IGCT (T3) and a thyristor T1 connected in series after being connected in anti-parallel, which controls turn-on in both directions and controls turn-off in one direction, has bidirectional current flow capability and bidirectional blocking voltage capability; refer to Figure 3I , the bidirectional full-controlled switch comprises a forward IGBT module and a reverse IGBT module connected in series, which can control turn-on and turn-off in both directions, has bidirectional current flow capability and bidirectional blocking voltage capability; refer to Figure 3J , the bidirectional full-controlled switch comprises a series circuit of an inverse blocking type IGCT (T3) connected in anti-parallel, which can control turn-on and turn-off in both directions, has bidirectional current flow capability and bidirectional blocking voltage capability; refer to Figure 3K , the sub-module series switch comprises a half-bridge sub-module connected in series, the half-bridge sub-module comprises two IGBT modules M1, M2 and a capacitor C1, a connection point of the two IGBT modules M1, M2 serves as a positive electrode of the half-bridge sub-module, and the other end of the IGBT module M2 serves as a negative electrode of the half-bridge sub-module, the half-bridge sub-modules are connected in series, which only controls turn-on and turn-off in one direction, has bidirectional current flow capability and unidirectional blocking voltage capability; refer to Figure 3LThe sub-module series switch comprises series-connected full-bridge sub-modules, the full-bridge sub-module comprises four IGBT modules M3, M4, M5 and M6 and a capacitor C1, the IGBT modules M3 and M4 are connected in series and the IGBT modules M5 and M6 are connected in series and then connected in parallel, and the capacitor C1 is also connected in parallel, the connection point of the series connection of the IGBT modules M3 and M4 is the positive pole of the full-bridge sub-module, the connection point of the series connection of the IGBT modules M5 and M6 is the negative pole of the sub-module, and the full-bridge sub-modules are connected in series, can be controlled to turn on and turn off in both directions, and have bidirectional current-carrying capacity and bidirectional blocking voltage capacity. Figure 3M The sub-module series switch comprises series-connected full-bridge sub-modules, the full-bridge sub-module comprises four IGBT modules M3, M4, M5 and M6 and a capacitor C1, the IGBT modules M3 and M4 are connected in series and the IGBT modules M5 and M6 are connected in series and then connected in parallel, and the capacitor C1 is also connected in parallel, the connection point of the series connection of the IGBT modules M3 and M4 is the positive pole of the full-bridge sub-module, the connection point of the series connection of the IGBT modules M5 and M6 is the negative pole of the sub-module, and the full-bridge sub-modules are connected in series, can be controlled to turn on and turn off in both directions, and have bidirectional current-carrying capacity and bidirectional blocking voltage capacity.

[0117] In some embodiments, the thyristor is configured with a corresponding trigger circuit and a buffer circuit; the IGBT is configured with a corresponding drive circuit and a buffer circuit; the IGCT or reverse blocking IGCT is configured with a corresponding drive circuit and a buffer circuit; the buffer circuit is at least composed of a capacitor or a series circuit of a resistor and a capacitor. The sub-module is configured with a protection circuit, and the protection circuit comprises but is not limited to a parallel-connected forward thyristor or / and a reverse thyristor or / and a bypass switch.

[0118] In some embodiments, the first half-controlled valve and / or the first fully-controlled valve, and / or the second half-controlled valve, and / or the third half-controlled valve and / or the second fully-controlled valve, and / or the third fully-controlled valve are connected in parallel with a lightning arrester; wherein the lightning arrester is connected in parallel according to devices, modules or valves.

[0119] In some embodiments, the first half-controlled valve and / or the first fully-controlled valve, and / or the second half-controlled valve, and / or the third half-controlled valve and / or the second fully-controlled valve, and / or the third fully-controlled valve further comprise a reactor.

[0120] The embodiment of the present application provides an active phase commutated converter, comprising at least one phase unit.

[0121] In some embodiments, in the case that the active phase commutated converter comprises at least one phase unit, the positive input end is the main branch anode bus of the at least one phase unit, the common end of the upper bridge arm circuit of the at least one phase unit and the lower bridge arm circuit of the at least one phase unit is the phase output end, and the negative input end is the main branch cathode bus of the at least one phase unit.

[0122] Referring to Figure 4 , the active phase commutated converter can be a three-phase six-bridge-arm bridge circuit, including three phase units, and the three phase units main branches include A-phase, B-phase and C-phase three upper bridge arm circuits 1 and A-phase, B-phase and C-phase three lower bridge arm circuits 2. The A-phase upper bridge arm circuit 1 includes a first half-controlled valve and / or a first fully-controlled valve V41 and a second half-controlled valve V42, which are connected in series, one end of the first half-controlled valve and / or the first fully-controlled valve V41 is connected with the main branch anode bus P1, and one end of the second half-controlled valve V42 is connected with one end of the second half-controlled valve V12 of the A-phase lower bridge arm circuit 2; the B-phase upper bridge arm circuit 1 includes a first half-controlled valve and / or a first fully-controlled valve V61 and a second half-controlled valve V62, which are connected in series, one end of the first half-controlled valve and / or the first fully-controlled valve V61 is connected with the main branch anode bus P1, and one end of the second half-controlled valve V62 is connected with one end of the second half-controlled valve V32 of the B-phase lower bridge arm circuit 2; the C-phase upper bridge arm circuit 1 includes a first half-controlled valve and / or a first fully-controlled valve V21 and a second half-controlled valve V22, which are connected in series, one end of the first half-controlled valve and / or the first fully-controlled valve V21 is connected with the main branch anode bus P1, and one end of the second half-controlled valve V22 is connected with one end of the second half-controlled valve V52 of the C-phase lower bridge arm circuit 2.

[0123] The A-phase lower bridge arm circuit 2 includes a first half-controlled valve and / or a first fully-controlled valve V11 and a second half-controlled valve V12, which are connected in series, one end of the first half-controlled valve and / or the first fully-controlled valve V11 is connected with the main branch cathode bus N1; the B-phase lower bridge arm circuit 2 includes a first half-controlled valve and / or a first fully-controlled valve V31 and a second half-controlled valve V32, which are connected in series, one end of the first half-controlled valve and / or the first fully-controlled valve V31 is connected with the main branch cathode bus N1; the C-phase lower bridge arm circuit 2 includes a first half-controlled valve and / or a first fully-controlled valve V51 and a second half-controlled valve V52, which are connected in series, one end of the first half-controlled valve and / or the first fully-controlled valve V51 is connected with the main branch cathode bus N1.

[0124] The three-phase unit auxiliary branch includes three upper bridge transfer circuits 3 of A phase, B phase and C phase, three lower bridge transfer circuits 4 of A phase, B phase and C phase and three main turn-off circuits 5 of A phase, B phase and C phase. The upper bridge transfer circuit 3 of A phase includes a third semi-controlled valve or a second fully-controlled valve V43, one end of the third semi-controlled valve or the second fully-controlled valve V43 is connected with the common end of the first semi-controlled valve and / or the first fully-controlled valve V41 and the second semi-controlled valve V42, the other end of the third semi-controlled valve or the second fully-controlled valve V43 is connected with one end of the third fully-controlled valve V410 of the main turn-off circuit 5 of A phase; the upper bridge transfer circuit 3 of B phase includes a third semi-controlled valve or a second fully-controlled valve V63, one end of the third semi-controlled valve or the second fully-controlled valve V63 is connected with the common end of the first semi-controlled valve and / or the first fully-controlled valve V61 and the second semi-controlled valve V62, the other end of the third semi-controlled valve or the second fully-controlled valve V63 is connected with one end of the third fully-controlled valve V630 of the main turn-off circuit 5 of B phase; the upper bridge transfer circuit 3 of C phase includes a third semi-controlled valve or a second fully-controlled valve V23, one end of the third semi-controlled valve or the second fully-controlled valve V23 is connected with the common end of the first semi-controlled valve and / or the first fully-controlled valve V21 and the second semi-controlled valve V22, the other end of the third semi-controlled valve or the second fully-controlled valve V23 is connected with one end of the third fully-controlled valve V250 of the main turn-off circuit 5 of C phase; the lower bridge transfer circuit 4 of A phase includes a third semi-controlled valve or a second fully-controlled valve V13, one end of the third semi-controlled valve or the second fully-controlled valve V13 is connected with the common end of the first semi-controlled valve and / or the first fully-controlled valve V11 and the second semi-controlled valve V12, the other end of the third semi-controlled valve or the second fully-controlled valve V13 is connected with one end of the third fully-controlled valve V410 of the main turn-off circuit 5 of A phase; the lower bridge transfer circuit 4 of B phase includes a third semi-controlled valve or a second fully-controlled valve V33, one end of the third semi-controlled valve or the second fully-controlled valve V33 is connected with the common end of the first semi-controlled valve and / or the first fully-controlled valve V31 and the second semi-controlled valve V32, the other end of the third semi-controlled valve or the second fully-controlled valve V33 is connected with one end of the third fully-controlled valve V630 of the main turn-off circuit 5 of B phase; the lower bridge transfer circuit 4 of C phase includes a third semi-controlled valve or a second fully-controlled valve V53, one end of the third semi-controlled valve or the second fully-controlled valve V53 is connected with the common end of the first semi-controlled valve and / or the first fully-controlled valve V51 and the second semi-controlled valve V52, the other end of the third semi-controlled valve or the second fully-controlled valve V53 is connected with one end of the third fully-controlled valve V250 of the main turn-off circuit 5 of C phase. The other end of the third fully-controlled valve V410 of the main turn-off circuit 5 of A phase is connected with the common end of the second semi-controlled valve V42 of the upper bridge arm circuit 1 of A phase and the second semi-controlled valve V12 of the lower bridge arm circuit 2 of A phase and serves as an A phase output end; the other end of the third fully-controlled valve V630 of the main turn-off circuit 5 of B phase is connected with the common end of the second semi-controlled valve V62 of the upper bridge arm circuit 1 of B phase and the second semi-controlled valve V32 of the lower bridge arm circuit 2 of B phase and serves as a B phase output end; the other end of the third fully-controlled valve V250 of the main turn-off circuit 5 of C phase is connected with the common end of the second semi-controlled valve V22 of the upper bridge arm circuit 1 of C phase and the second semi-controlled valve V52 of the lower bridge arm circuit 2 of C phase and serves as a C phase output end.

[0125] In some embodiments, the upper arm circuit and lower arm circuit of the main branch of the phase unit may also adopt a first fully controlled valve, a first partially controlled valve and a second partially controlled valve, respectively; the first fully controlled valve, the first partially controlled valve and the second partially controlled valve are connected in series.

[0126] This invention provides an active commutation converter, comprising: at least one phase unit and an auxiliary shutdown circuit.

[0127] In some embodiments, the active commutation converter includes a first auxiliary shutdown circuit, the circuit of which is connected in parallel with the circuit of the upper or lower arm circuit of at least one main branch and the circuit of the main shutdown circuit of at least one auxiliary branch.

[0128] In some embodiments, one end of the first auxiliary shutdown circuit is connected to the anode bus of the main branch of the active commutation converter, and the other end of the first auxiliary shutdown circuit is connected to the cathode bus of the main branch of the active commutation converter; the first auxiliary shutdown circuit includes a fourth full control valve and a fifth semi control valve, which are connected in series.

[0129] In some embodiments, the upper arm circuit in at least one phase unit may share the fourth full control valve and the fifth half control valve of the upper arm of the first auxiliary shutdown circuit, and the lower arm circuit in at least one phase unit may share the fourth full control valve and the fifth half control valve of the lower arm of the first auxiliary shutdown circuit.

[0130] In some embodiments, the first auxiliary shutdown circuit further includes a seventh semi-controlled valve or a first uncontrolled valve, wherein the seventh semi-controlled valve or the first uncontrolled valve and the fourth fully controlled valve are connected in series.

[0131] Reference Figure 5 The first auxiliary shutdown circuit 6 includes: an auxiliary shutdown circuit for the upper bridge arm circuit 1 and an auxiliary shutdown circuit for the lower bridge arm circuit 2. The auxiliary shutdown circuit for the upper bridge arm circuit 1 includes a fourth fully controlled valve V71, a fifth partially controlled valve V81, a seventh partially controlled valve or a first uncontrolled valve V44 for phase A, a seventh partially controlled valve or a first uncontrolled valve V64 for phase B, and a seventh partially controlled valve or a first uncontrolled valve V24 for phase C. The auxiliary shutdown circuit for the lower bridge arm circuit 2 includes a fourth fully controlled valve V72, a fifth partially controlled valve V82, a seventh partially controlled valve or a first uncontrolled valve V14 for phase A, a seventh partially controlled valve or a first uncontrolled valve V34 for phase B, and a seventh partially controlled valve or a first uncontrolled valve V54 for phase C. The upper bridge arms of phases A, B, and C share the fourth fully controlled valve V71 and the fifth partially controlled valve V81, and the lower bridge arms of phases A, B, and C share the fourth fully controlled valve V72 and the fifth partially controlled valve V82.

[0132] In some embodiments, the active commutation converter may further include a second auxiliary shutdown circuit; the second auxiliary shutdown circuit is connected in parallel with the at least one phase unit.

[0133] In some embodiments, one end of the second auxiliary turn-off circuit is connected with the main branch anode bus P1, and the other end of the second auxiliary turn-off circuit is connected with the main branch cathode bus N1; the second auxiliary turn-off circuit 7 comprises a fifth fully controlled valve and a sixth semi-controlled valve, and the fifth fully controlled valve and the sixth semi-controlled valve are connected in series.

[0134] In some embodiments, the upper bridge arm circuit and the lower bridge arm circuit in the at least one phase unit can share the fifth fully controlled valve and the sixth semi-controlled valve of the second auxiliary turn-off circuit.

[0135] With reference to Figure 6 , one end of the second auxiliary turn-off circuit 7 is connected with the main branch anode bus P1, and the other end of the second auxiliary turn-off circuit 7 is connected with the main branch cathode bus N1; the second auxiliary turn-off circuit 7 comprises a fifth fully controlled valve V73 and a sixth semi-controlled valve V83, and the fifth fully controlled valve V73 and the sixth semi-controlled valve V83 are connected in series.

[0136] In some embodiments, the fifth semi-controlled valve and the sixth semi-controlled valve comprise unidirectional semi-controlled switches, the fourth fully controlled valve and the fifth fully controlled valve comprise at least one of unidirectional fully controlled switches, bidirectional fully controlled switches and submodule series switches, and the first non-controlled valve comprises a non-controlled switch; the non-controlled switch is composed of non-controlled turn-on and turn-off semiconductor devices in series, and the non-controlled turn-on and turn-off semiconductor devices include but are not limited to diodes.

[0137] The embodiment of the present application provides an active phase commutation converter, comprising: a main turn-off circuit of at least one main branch and at least one auxiliary branch, wherein one end of the main turn-off circuit of the at least one auxiliary branch is used as a phase output end, the other end of the main turn-off circuit of the at least one auxiliary branch is connected with a common point of series connection of upper bridge arm circuits and lower bridge arm circuits of the at least one main branch, and the upper bridge arm circuits and the lower bridge arm circuits of the at least one main branch respectively comprise first fully controlled valves.

[0138] With reference to Figure 7The active commutation converter can be a three-phase six-arm bridge circuit, including three main branches and three main shutdown circuits. The three main branches include three upper bridge arm circuits 1 (phase A, phase B, and phase C) and three lower bridge arm circuits 2 (phase A, phase B, and phase C). Phase A upper arm circuit 1 includes a first full control valve V41, one end of which is connected to the main branch anode bus P1, and the other end of which is connected to one end of the first full control valve V11 of Phase A lower arm circuit 2; Phase B upper arm circuit 1 includes a first full control valve V61, one end of which is connected to the main branch anode bus P1, and the other end of which is connected to one end of the first full control valve V31 of Phase B lower arm circuit 2; Phase C upper arm circuit 1 includes a first full control valve V21, one end of which is connected to the main branch anode bus P1, and the other end of which is connected to one end of the first full control valve V51 of Phase C lower arm circuit 2. Phase A lower bridge arm circuit 2 includes a first full control valve V11, the other end of which is connected to the main branch cathode bus N1; Phase B lower bridge arm circuit 2 includes a first full control valve V31, the other end of which is connected to the main branch cathode bus N1; Phase C lower bridge arm circuit 2 includes a first full control valve V51, the other end of which is connected to the main branch cathode bus N1.

[0139] The three main shutdown circuits include phase A, phase B, and phase C. Phase A main shutdown circuit 5 includes a third full control valve V410. One end of the third full control valve V410 is connected to the common terminal of the first full control valve V41 of the upper bridge arm circuit 1 and the first full control valve V11 of the lower bridge arm circuit 2 of phase A. The other end of the third full control valve V410 is the output terminal of phase A. Phase B main shutdown circuit 5 includes a third full control valve V630. One end of the third full control valve V630 is connected to the common terminal of the first full control valve V61 of the upper bridge arm circuit 1 and the first full control valve V31 of the lower bridge arm circuit 2 of phase A. The other end of the third full control valve V630 is the output terminal of phase B. Phase C main shutdown circuit 5 includes a third full control valve V250. One end of the third full control valve V250 is connected to the common terminal of the first full control valve V21 of the upper bridge arm circuit 1 and the first full control valve V51 of the lower bridge arm circuit 2 of phase A. The other end of the third full control valve V250 is the output terminal of phase C.

[0140] In some embodiments, the upper arm circuit and lower arm circuit of at least one main branch further include a second semi-controlled valve.

[0141] Reference Figure 8 ,by Figure 7As a basis, the active phase commutated converter can be a three-phase six-bridge-arm bridge circuit, including three main branches and a main turn-off circuit, the three main branches including three upper bridge-arm circuits 1 of A-phase, B-phase and C-phase and three lower bridge-arm circuits 2 of A-phase, B-phase and C-phase. The A-phase upper bridge-arm circuit 1 includes a first fully controlled valve V41 and a second semi-controlled valve V42, the first fully controlled valve V41 and the second semi-controlled valve V42 being connected in series, one end of the first fully controlled valve V41 being connected with a main branch anode bus P1, and one end of the second semi-controlled valve V42 being connected with one end of a second semi-controlled valve V12 of the A-phase lower bridge-arm circuit 2; the B-phase upper bridge-arm circuit 1 includes a first fully controlled valve V61 and a second semi-controlled valve V62, the first fully controlled valve V61 and the second semi-controlled valve V62 being connected in series, one end of the first fully controlled valve V61 being connected with the main branch anode bus P1, and one end of the second semi-controlled valve V62 being connected with one end of a second semi-controlled valve V32 of the B-phase lower bridge-arm circuit 2; and the C-phase upper bridge-arm circuit 1 includes a first fully controlled valve V21 and a second semi-controlled valve V22, the first fully controlled valve V21 and the second semi-controlled valve V22 being connected in series, one end of the first fully controlled valve V21 being connected with the main branch anode bus P1, and one end of the second semi-controlled valve V22 being connected with one end of a second semi-controlled valve V52 of the C-phase lower bridge-arm circuit 2.

[0142] The A-phase lower bridge-arm circuit 2 includes a first fully controlled valve V11 and a second semi-controlled valve V12, the first fully controlled valve V11 and the second semi-controlled valve V12 being connected in series, one end of the first fully controlled valve V11 being connected with a main branch cathode bus N1; the B-phase lower bridge-arm circuit 2 includes a first fully controlled valve V31 and a second semi-controlled valve V32, the first fully controlled valve V31 and the second semi-controlled valve V32 being connected in series, one end of the first fully controlled valve V31 being connected with the main branch cathode bus N1; and the C-phase lower bridge-arm circuit 2 includes a first fully controlled valve V51 and a second semi-controlled valve V52, the first fully controlled valve V51 and the second semi-controlled valve V52 being connected in series, one end of the first fully controlled valve V51 being connected with the main branch cathode bus N1.

[0143] The A-phase main turn-off circuit 5 includes a third fully controlled valve V410, one end of the third fully controlled valve V410 being connected with a common end of the second semi-controlled valve V42 of the A-phase upper bridge-arm circuit 1 and the second semi-controlled valve V12 of the A-phase lower bridge-arm circuit 2, and the other end of the third fully controlled valve V410 being an A-phase output end; the B-phase main turn-off circuit 5 includes a third fully controlled valve V630, one end of the third fully controlled valve V630 being connected with a common end of the second semi-controlled valve V62 of the A-phase upper bridge-arm circuit 1 and the second semi-controlled valve V32 of the A-phase lower bridge-arm circuit 2, and the other end of the third fully controlled valve V630 being a B-phase output end; and the C-phase main turn-off circuit 5 includes a third fully controlled valve V250, one end of the third fully controlled valve V250 being connected with a common end of the second semi-controlled valve V22 of the C-phase upper bridge-arm circuit 1 and the second semi-controlled valve V52 of the A-phase lower bridge-arm circuit 2, and the other end of the third fully controlled valve V250 being a C-phase output end.

[0144] This invention provides an active commutation converter, comprising: at least one main branch, at least one auxiliary branch, a main shutdown circuit, and an auxiliary shutdown circuit; wherein, one end of the main shutdown circuit of the at least one auxiliary branch serves as a phase output terminal, and the other end of the main shutdown circuit of the at least one auxiliary branch is connected to a common point where the upper arm circuit and the lower arm circuit of the at least one main branch are connected in series.

[0145] In some embodiments, the active commutation converter includes a first auxiliary shutdown circuit, the circuit of which is connected in parallel with the circuit of the upper or lower arm circuit of at least one main branch and the circuit of the main shutdown circuit of at least one auxiliary branch.

[0146] In some embodiments, one end of the first auxiliary shutdown circuit is connected to the anode bus of the main branch, and the other end of the first auxiliary shutdown circuit is connected to the cathode bus of the main branch; the first auxiliary shutdown circuit includes a fourth full control valve and a fifth semi control valve; the fourth full control valve and the fifth semi control valve are connected in series.

[0147] In some embodiments, the upper arm circuit in at least one main branch may share the fourth full control valve and the fifth half control valve of the upper arm of the first auxiliary shutdown circuit, and the lower arm circuit in at least one main branch may share the fourth full control valve and the fifth half control valve of the lower arm of the first auxiliary shutdown circuit.

[0148] In some embodiments, the first auxiliary shutdown circuit further includes a seventh semi-controlled valve or a first uncontrolled valve, wherein the seventh semi-controlled valve or the first uncontrolled valve and the fourth fully controlled valve are connected in series.

[0149] Reference Figure 9 ,by Figure 7 Based on this, the first auxiliary shutdown circuit 6 includes: an auxiliary shutdown circuit for the upper bridge arm circuit 1 and an auxiliary shutdown circuit for the lower bridge arm circuit 2. The auxiliary shutdown circuit for the upper bridge arm circuit 1 includes a fourth fully controlled valve V71, a fifth partially controlled valve V81, a seventh partially controlled valve or a first uncontrolled valve V44 for phase A, a seventh partially controlled valve or a first uncontrolled valve V64 for phase B, and a seventh partially controlled valve or a first uncontrolled valve V24 for phase C. The auxiliary shutdown circuit for the lower bridge arm circuit 2 includes a fourth fully controlled valve V72, a fifth partially controlled valve V82, a seventh partially controlled valve or a first uncontrolled valve V14 for phase A, a seventh partially controlled valve or a first uncontrolled valve V34 for phase B, and a seventh partially controlled valve or a first uncontrolled valve V54 for phase C. The upper bridge arms of phases A, B, and C share the fourth fully controlled valve V71 and the fifth partially controlled valve V81, and the lower bridge arms of phases A, B, and C share the fourth fully controlled valve V72 and the fifth partially controlled valve V82.

[0150] In some embodiments, the active commutation converter may further include a second auxiliary shutdown circuit; the second auxiliary shutdown circuit is connected in parallel with the at least one main branch.

[0151] In some embodiments, one end of the second auxiliary shutdown circuit is connected to the anode bus of the main branch, and the other end of the second auxiliary shutdown circuit is connected to the cathode bus of the main branch; the second auxiliary shutdown circuit includes a fifth full control valve and a sixth semi control valve, which are connected in series. In some embodiments, the upper bridge arm circuit and the lower bridge arm circuit in at least one phase unit may share the fifth full control valve and the sixth semi control valve of the second auxiliary shutdown circuit.

[0152] Reference Figure 10 ,by Figure 8 Based on this, one end of the second auxiliary shut-off circuit 7 is connected to the anode bus P1 of the main branch, and the other end of the second auxiliary shut-off circuit 7 is connected to the cathode bus N1 of the main branch. The second auxiliary shut-off circuit 7 includes a fifth full control valve V73 and a sixth semi control valve V83, which are connected in series.

[0153] In some embodiments, the auxiliary shutdown circuit is connected to the main branch anode bus and the main branch cathode bus of the active commutation converter via a disconnecting switch and / or a knife switch.

[0154] In some embodiments, the fifth semi-controlled valve and / or the sixth semi-controlled valve are connected in parallel with surge arresters, the fourth fully controlled valve and / or the fifth fully controlled valve are connected in parallel with surge arresters, and the first uncontrolled valve is connected in parallel with a surge arrester. The surge arresters are connected in parallel as devices, modules, or valves.

[0155] Optionally, the fifth and / or sixth semi-controlled valves may also include a reactor.

[0156] In some embodiments, refer to Figure 11 , Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 as well as Figure 19 The diagram shows the valve structures corresponding to each of the first semi-controlled valve and / or the first fully controlled valve, each of the second semi-controlled valve, each of the third semi-controlled valve or the second fully controlled valve, each of the third fully controlled valve, each of the fifth semi-controlled valve, each of the fourth fully controlled valve, each of the sixth semi-controlled valve, each of the fifth fully controlled valve, and each of the seventh semi-controlled valve or the first uncontrolled valve.

[0157] Reference Figure 11 The upper bridge arm circuit 1 and lower bridge arm circuit 2 of the main branch of the phase unit adopt the first half-controlled valve and the second half-controlled valve, respectively; the upper bridge transfer circuit 3 and lower bridge transfer circuit 4 of the auxiliary branch adopt the third half-controlled valve, respectively; and the main shutdown circuit 5 adopts the third fully controlled valve. The first half-controlled valve, the second half-controlled valve, and the third half-controlled valve respectively adopt... Figure 3B The unidirectional semi-controlled switch shown is composed of thyristors connected in series; the third fully controlled valve uses...Figure 3L The sub-module series switch shown is composed of full-bridge sub-modules in series. During normal commutation, the third forced commutated valve is used to provide additional commutation voltage, force commutation current, and reduce the reactive loss of the active commutation converter. During fault, if the third forced commutated valve cannot provide enough commutation voltage, the second forced commutated valve is used to provide additional higher commutation voltage.

[0158] Referring to Figure 12 , the upper bridge arm circuit 1 and the lower bridge arm circuit 2 of the main branch of the phase unit respectively use the first and second forced commutated valves, the upper bridge transfer circuit 3 and the lower bridge transfer circuit 4 of the auxiliary branch respectively use the second forced commutated valve, and the main forced commutation circuit 5 uses the third forced commutated valve. The first and second forced commutated valves respectively use Figure 3B The unidirectional half-controlled switch shown is composed of thyristors connected in series; the second forced commutated valve uses Figure 3F The unidirectional forced commutation switch shown is composed of reverse blocking IGCTs connected in series; the third forced commutated valve uses Figure 3L The sub-module series switch shown is composed of full-bridge sub-modules in series. During normal commutation, the third forced commutated valve is used to provide additional commutation voltage, force commutation current, and reduce the reactive loss of the active commutation converter. During fault, if the third forced commutated valve cannot provide enough commutation voltage, the second forced commutated valve is used to provide additional higher commutation voltage.

[0159] Referring to Figure 13 , the upper bridge arm circuit 1 and the lower bridge arm circuit 2 of the main branch of the phase unit respectively use the first and second forced commutated valves, the upper bridge transfer circuit 3 and the lower bridge transfer circuit 4 of the auxiliary branch respectively use the third forced commutated valve, and the main forced commutation circuit 5 uses the third forced commutated valve. The first and second forced commutated valves respectively use Figure 3B The unidirectional half-controlled switch shown is composed of thyristors connected in series; the second forced commutated valve uses Figure 3F The unidirectional forced commutation switch shown is composed of reverse blocking IGCTs connected in series; the third forced commutated valve uses Figure 3L The sub-module series switch shown is composed of full-bridge sub-modules in series. During normal commutation, the third forced commutated valve is used to provide additional commutation voltage, force commutation current, and reduce the reactive loss of the active commutation converter. During fault, if the third forced commutated valve cannot provide enough commutation voltage, the second forced commutated valve is used to provide additional higher commutation voltage.

[0160] Referring to Figure 14 , the upper bridge arm circuit 1 and the lower bridge arm circuit 2 of the main branch of the phase unit respectively use the first and second forced commutated valves, the upper bridge transfer circuit 3 and the lower bridge transfer circuit 4 of the auxiliary branch respectively use the third forced commutated valve, and the main forced commutation circuit 5 uses the third forced commutated valve. The first, second, and third forced commutated valves respectively use Figure 3B The unidirectional half-controlled switch shown is composed of thyristors connected in series; the third forced commutated valve uses Figure 3LThe shown sub-module series switch is composed of full-bridge sub-modules in series. The converter further comprises a first auxiliary turn-off circuit 6, which employs a fourth fully controlled valve, a fifth semi-controlled valve and a first uncontrolled valve. The fourth fully controlled valve employs Figure 3E The shown unidirectional fully controlled switch is composed of IGBT modules connected in series; the fifth semi-controlled valve employs Figure 3B The shown unidirectional semi-controlled switch is composed of thyristors connected in series; the first uncontrolled valve employs Figure 3A The shown uncontrolled switch is composed of diodes connected in series. During normal commutation, the third fully controlled valve is used to provide additional commutation voltage to force turn-off current and reduce the reactive loss of the active commutation converter; during fault, if the third fully controlled valve cannot provide sufficient commutation voltage, the fourth fully controlled valve is used to provide additional higher commutation voltage.

[0161] With reference to Figure 15 , the upper bridge arm circuit 1 and the lower bridge arm circuit 2 of the main branch of the phase unit respectively employ a first semi-controlled valve and a second semi-controlled valve, the upper bridge transfer circuit 3 and the lower bridge transfer circuit 4 of the auxiliary branch respectively employ a third semi-controlled valve, and the main turn-off circuit 5 employs a third fully controlled valve. The first semi-controlled valve and the second semi-controlled valve respectively employ Figure 3C The shown bidirectional semi-controlled switch is composed of anti-parallel thyristors connected in series; the third semi-controlled valve employs Figure 3B The shown unidirectional semi-controlled switch is composed of thyristors connected in series; the third fully controlled valve employs Figure 3L The shown sub-module series switch is composed of full-bridge sub-modules in series. The converter further comprises a second auxiliary turn-off circuit 7, which employs a fifth fully controlled valve and a sixth semi-controlled valve. The fifth fully controlled valve employs Figure 3E The shown unidirectional fully controlled switch is composed of IGBT modules connected in series; the sixth semi-controlled valve employs Figure 3B The shown unidirectional semi-controlled switch is composed of thyristors connected in series. During normal commutation, the third fully controlled valve is used to provide additional commutation voltage to force turn-off current and reduce the reactive loss of the active commutation converter; during fault, if the third fully controlled valve cannot provide sufficient commutation voltage, the fifth fully controlled valve is used to provide additional higher commutation voltage.

[0162] With reference to Figure 16 , the upper bridge arm circuit 1 and the lower bridge arm circuit 2 of the main branch respectively employ a first fully controlled valve, and the main turn-off circuit 5 of the auxiliary branch employs a third fully controlled valve. The first fully controlled valve employs Figure 3F The shown unidirectional fully controlled switch is composed of inverse blocking type IGCTs connected in series; the third fully controlled valve employs Figure 3LThe sub-module series switch shown is composed of full-bridge sub-modules connected in series. During normal commutation, the third full control valve is turned off to provide additional commutation voltage, forcing the turn-off current and reducing the reactive power loss of the active commutation converter. During a fault, if the third full control valve cannot provide sufficient commutation voltage, the first full control valve is turned off to provide an additional, higher commutation voltage.

[0163] Reference Figure 17 The upper arm circuit 1 and lower arm circuit 2 of the main branch use a first fully controlled valve and a second partially controlled valve, respectively, while the main shut-off circuit 5 of the auxiliary branch uses a third fully controlled valve. The first fully controlled valve uses... Figure 3F The unidirectional fully controlled switch shown is composed of reverse-resistance IGCTs connected in series; the second semi-controlled valve adopts... Figure 3B The unidirectional semi-controlled switch shown is composed of thyristors connected in series; the third fully controlled valve uses... Figure 3L The sub-module series switch shown is composed of full-bridge sub-modules connected in series. During normal commutation, the third full control valve is turned off to provide additional commutation voltage, forcing the turn-off current and reducing the reactive power loss of the active commutation converter. During a fault, if the third full control valve cannot provide sufficient commutation voltage, the first full control valve is turned off to provide an additional, higher commutation voltage.

[0164] Reference Figure 18 The upper arm circuit 1 and lower arm circuit 2 of the main branch each use a first semi-controlled valve, while the main shut-off circuit 5 of the auxiliary branch uses a third fully controlled valve. The first semi-controlled valve uses... Figure 3B The unidirectional semi-controlled switch shown is composed of thyristors connected in series; the third fully controlled valve uses... Figure 3L The sub-module series switch shown is composed of full-bridge sub-modules connected in series. The converter also includes a first auxiliary shutdown circuit 6, and the second auxiliary shutdown circuit 6 employs a fourth fully controlled valve, a fifth partially controlled valve, and a first uncontrolled valve. The fourth fully controlled valve employs... Figure 3E The unidirectional fully controlled switch shown is composed of IGBT modules connected in series; the fifth semi-controlled valve adopts... Figure 3B The unidirectional semi-controlled switch shown is composed of thyristors connected in series; the first uncontrolled valve adopts... Figure 3A The uncontrolled switch shown is composed of diodes connected in series. During normal commutation, the third full control valve is turned off to provide additional commutation voltage, forcing the turn-off current and reducing the reactive power loss of the active commutation converter. During faults, if the third full control valve cannot provide sufficient commutation voltage, the fourth full control valve is turned off to provide an additional, higher commutation voltage.

[0165] Reference Figure 19 The upper arm circuit 1 and lower arm circuit 2 of the main branch use a first fully controlled valve and a second partially controlled valve, respectively, while the main shut-off circuit 5 of the auxiliary branch uses a third fully controlled valve. The first fully controlled valve uses... Figure 3EThe unidirectional fully controlled switch shown is composed of IGBT modules connected in series; the second semi-controlled valve adopts Figure 3C The bidirectional semi-controlled switch shown is composed of thyristors connected in anti-parallel and in series; the third fully controlled valve adopts Figure 3L The sub-module series switch shown is composed of full-bridge sub-modules connected in series. The converter further comprises a second auxiliary turn-off circuit 7, which adopts a fifth fully controlled valve and a sixth semi-controlled valve. The fifth fully controlled valve adopts Figure 3E The unidirectional fully controlled switch shown is composed of IGBT modules connected in series; the sixth semi-controlled valve adopts Figure 3B The unidirectional semi-controlled switch shown is composed of thyristors connected in series. During normal commutation, the third fully controlled valve turn-off is used to provide additional commutation voltage, force turn-off current, and reduce the reactive loss of the active commutation converter; during a fault, if the third fully controlled valve turn-off cannot provide sufficient commutation voltage, the fifth fully controlled valve turn-off is used to provide additional higher commutation voltage. It should be noted that the positions of the first fully controlled valve and the second semi-controlled valve in the embodiment can be interchanged.

[0166] In some embodiments, Figure 11 , Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 , Figure 17 , Figure 18 and Figure 19 Each first semi-controlled valve and / or first fully controlled valve, each second semi-controlled valve, each third semi-controlled valve or second fully controlled valve, each third fully controlled valve, each fifth semi-controlled valve, each fourth fully controlled valve, each sixth semi-controlled valve, each fifth fully controlled valve, and each seventh semi-controlled valve or first non-controlled valve are connected in parallel with a lightning arrester.

[0167] The present application provides an active commutation converter control method, which is executed by an electronic device. The electronic device can be a control device, a server, or a terminal device. The control device is an independent physical controller. The server can be an independent physical server, a server cluster or a distributed system composed of multiple physical servers, or a cloud server providing cloud computing services. The terminal device can be a smartphone, a tablet computer, a notebook computer, a desktop computer, etc., but is not limited thereto. The control device, the server, and the terminal device can be directly or indirectly connected through wired or wireless communication, and the embodiments of the present application do not make specific limitations.

[0168] Referring to Figure 20 , an active commutation converter control method comprises steps S101 and S102, wherein,

[0169] S101, in the case that the operating parameter information of the active commutation converter is acquired, generating the inverter state control information based on the parameter information, and controlling the main branch to operate in the inverter state based on the inverter state control information.

[0170] In some embodiments, the electronic device monitors the operating state of the active commutation converter in real time, and acquires the operating parameter information of the active commutation converter operating state, such as AC voltage, DC current, etc. In the case that the electronic device acquires the operating state of the active commutation converter, the electronic device generates the inverter state control information, such as trigger pulse, and the active commutation converter operates in the inverter state according to the six-pulse inverter working mode based on the inverter state control information; for example, in a certain time period within the AC voltage cycle, the electronic device controls the first half-controlled valve and / or the first fully-controlled valve V41 and the second half-controlled valve V42 of the A-phase upper bridge arm circuit, and the first half-controlled valve and / or the first fully-controlled valve V31 and the second half-controlled valve V32 of the B-phase lower bridge arm circuit to operate in the inverter state.

[0171] S102, in the case that the active commutation converter includes at least one phase unit and / or auxiliary turn-off circuit, and the acquired turn-off angle reference value is less than the minimum turn-off angle constant value or the commutation failure information, generating the first circuit conduction instruction and the first negative voltage control information, and controlling the transfer circuit in the auxiliary branch corresponding to the commutation bridge arm to conduct based on the first circuit conduction instruction, and controlling the main turn-off circuit of the auxiliary branch corresponding to the commutation bridge arm to present negative voltage based on the first negative voltage control information; in the case that the second half-controlled valve of the commutation bridge arm of the main branch recovers turn-off, generating the first circuit turn-off instruction to control the main turn-off circuit of the auxiliary branch to turn off; or,

[0172] In the case that the active commutation converter includes the main branch and the main turn-off circuit of the auxiliary branch, and the acquired turn-off angle reference value is less than the minimum turn-off angle constant value or the commutation failure information, generating the first circuit turn-off instruction to control the main turn-off circuit of the auxiliary branch to turn off.

[0173] In some embodiments, the commutation failure information includes the fault information causing the natural commutation failure of the commutation bridge arm of the main branch. The above-mentioned commutation failure information includes the AC system fault or DC system fault connected to the active commutation converter, the AC system fault can be judged according to the increase of the AC voltage zero sequence component, the AC voltage mutation, the AC voltage amplitude drop, the increase of the AC voltage harmonic, the increase of the DC current, the DC system fault can be judged according to the DC voltage drop and the increase of the DC current, but not limited thereto.

[0174] In some embodiments, the natural commutation failure is a commutation failure that occurs when commutation is only relied on the commutation voltage provided by the AC system. Whether the natural commutation failure occurs can be determined according to the turn-off time of the first and second half-controlled valves of the commutation bridge arm, the AC current at the grid side or the valve side, and the AC voltage. If the first and second half-controlled valves of the commutation bridge arm have not been turned off at the time when they start to bear positive voltage under normal AC voltage, it is determined that the natural commutation failure occurs, but this is not limiting.

[0175] The commutation bridge arm is an upper bridge arm circuit or a lower bridge arm circuit. The electronic device obtains a turn-off angle reference value and compares the turn-off angle reference value with a preset minimum turn-off angle setting value. In the case where the turn-off angle reference value is less than the minimum turn-off angle setting value, during commutation, the electronic device generates a first circuit conduction instruction and first negative voltage control information. Subsequently, the electronic device controls the third half-controlled valve and / or the second fully-controlled valve of the transfer circuit in the auxiliary branch corresponding to the commutation bridge arm to be turned on based on the circuit conduction instruction, and controls the third fully-controlled valve of the main turn-off circuit of the auxiliary branch corresponding to the commutation bridge arm to present negative voltage based on the first negative voltage control information, so as to transfer the current of the second half-controlled valve of the commutation bridge arm to the transfer circuit and the main turn-off circuit of the auxiliary branch. Taking the A-phase upper bridge arm circuit as an example, when the A-phase upper bridge arm circuit commutates to the B-phase upper bridge arm circuit, if the turn-off angle reference value is less than the minimum turn-off angle setting value, such as 3 degrees, or the natural commutation failure of the first half-controlled valve and / or the first fully-controlled valve V41 and the second half-controlled valve V42 of the A-phase upper bridge arm circuit in the main branch will occur, the electronic device controls the third half-controlled valve and / or the second fully-controlled valve V43 of the A-phase upper bridge transfer circuit in the auxiliary branch to be turned on based on the first circuit conduction instruction, and controls the third fully-controlled valve V410 of the main turn-off circuit to present negative voltage based on the first negative voltage control information, such as controlling Figure 3L The conduction of the IGBT modules M4 and M5 in the middle makes the full-bridge sub-module present negative voltage of the capacitor C1, so as to transfer the current of the second half-controlled valve V42 of the A-phase upper bridge arm circuit to the A-phase upper bridge transfer circuit and the main turn-off circuit in the auxiliary branch. Taking the A-phase lower bridge arm circuit as an example, when the A-phase lower bridge arm circuit commutates to the B-phase lower bridge arm circuit, if the turn-off angle reference value is less than the minimum turn-off angle setting value, such as 3 degrees, or the natural commutation failure of the first half-controlled valve and / or the first fully-controlled valve V11 and the second half-controlled valve V12 of the A-phase lower bridge arm circuit in the main branch will occur, the electronic device controls the third half-controlled valve and / or the second fully-controlled valve V13 of the A-phase lower bridge transfer circuit in the auxiliary branch to be turned on based on the first circuit conduction instruction, and controls the third fully-controlled valve V410 of the main turn-off circuit to present negative voltage based on the first negative voltage control information, such as controlling Figure 3L The conduction of the IGBT modules M3 and M6 in the middle makes the full-bridge sub-module present negative voltage of the capacitor C1, so as to transfer the current of the second half-controlled valve V12 of the A-phase lower bridge arm circuit to the A-phase lower bridge transfer circuit and the main turn-off circuit in the auxiliary branch.

[0176] The electronic device generates a first circuit turn-off instruction in the case that the second half-controlled valve of the phase-changing bridge arm of the main branch recovers turn-off, and controls the main turn-off circuit of the auxiliary branch to turn off. Taking the A-phase upper bridge arm circuit as an example, in the case that the second half-controlled valve V42 of the A-phase upper bridge arm circuit recovers turn-off, the electronic device controls the third fully-controlled valve V410 of the main turn-off circuit to turn off based on the first circuit turn-off instruction, the third fully-controlled valve V410 presents a capacitor positive voltage, thereby providing an additional phase-changing voltage, so that the current is commutated from the A-phase upper bridge arm circuit to the B-phase upper bridge arm circuit; taking the A-phase lower bridge arm circuit as an example, in the case that the second half-controlled valve V12 of the A-phase lower bridge arm circuit recovers turn-off, the electronic device controls the third fully-controlled valve V410 of the main turn-off circuit to turn off based on the first circuit turn-off instruction, the third fully-controlled valve V410 presents a capacitor positive voltage, thereby providing an additional phase-changing voltage, so that the current is commutated from the A-phase lower bridge arm circuit to the B-phase lower bridge arm circuit.

[0177] In some embodiments, before controlling the main turn-off circuit of the auxiliary branch to turn off, second negative voltage control information is generated, and the main turn-off circuit of the auxiliary branch corresponding to the bridge arm to be commutated is controlled to present a negative voltage based on the second negative voltage control information.

[0178] In some embodiments, in the case that the main active phase-changing converter is in normal operation, the turn-off angle reference value is set to be less than the minimum turn-off angle setting value; in the case that the turn-off angle reference value is less than the minimum turn-off angle setting value and the first half-controlled valve of the phase-changing bridge arm of the main branch recovers turn-off, a first circuit turn-off instruction is generated to control the third fully-controlled valve corresponding to the phase-changing bridge arm to turn off.

[0179] In some embodiments, in the case that the capacitor voltage of the full-bridge sub-module, the quasi-full-bridge sub-module or the clamped double sub-module of the third fully-controlled valve of the main turn-off circuit is lower than the rated value and exceeds a first threshold value, and the second half-controlled valve of the phase-changing bridge arm of the main branch recovers turn-off, the first circuit turn-off instruction is generated in advance; or / and the number of the full-bridge sub-modules, the quasi-full-bridge sub-modules or the clamped double sub-modules of the third fully-controlled valve of the main turn-off circuit is increased; or / and the first circuit turn-on instruction and the first negative voltage control information are generated in advance; the first threshold value is in the range of 0.01-0.6 times the rated capacitor voltage.

[0180] In some embodiments, in the case that the capacitor voltage of the sub-module of the third fully-controlled valve of the main turn-off circuit is greater than or equal to the rated value and exceeds a second threshold value, and the second half-controlled valve of the phase-changing bridge arm of the main branch recovers turn-off, the first circuit turn-off instruction is generated in advance; or / and the number of the sub-modules of the third fully-controlled valve of the main turn-off circuit is reduced; or / and the first circuit turn-on instruction and the first negative voltage control information are generated in advance; the second threshold value is in the range of 0.01-0.6 times the rated capacitor voltage.

[0181] In some embodiments, the control of the main turn-off circuit presenting negative voltage is achieved by controlling the switch device in the third fully controlled valve sub-module to be turned on so that the sub-module presents capacitive negative voltage in the current flow direction.

[0182] In some embodiments, the recovery turn-off of the second semi-controlled valve of the phase-changing bridge arm of the main branch is determined according to the reverse recovery time of the second semi-controlled valve, and the reverse recovery time is greater than or equal to the reverse recovery time of the thyristor contained in the second semi-controlled valve.

[0183] In some embodiments, in the case of overvoltage or failure of the third fully controlled valve, the second semi-controlled valve or the fourth semi-controlled valve of the same phase unit of the third fully controlled valve is controlled to be turned on.

[0184] In some embodiments, in the case that the upper bridge arm circuit and the lower bridge arm circuit respectively include the first fully controlled valve, the control method further comprises: generating a second circuit turn-off instruction in the case that the phase-changing fault information is obtained and the main turn-off circuit cannot provide sufficient phase-changing voltage, and controlling the first fully controlled valve to be turned off based on the second circuit turn-off instruction.

[0185] In some embodiments, in the case that the upper bridge transfer circuit and the lower bridge transfer circuit respectively include the second fully controlled valve, the control method further comprises: generating a third circuit turn-off instruction in the case that the phase-changing fault information is obtained and the main turn-off circuit cannot provide sufficient phase-changing voltage, and controlling the second fully controlled valve to be turned off based on the third circuit turn-off instruction.

[0186] In some embodiments, in the case that the active phase-changing current transformer further comprises an auxiliary turn-off circuit, the control method further comprises: generating a second circuit turn-on instruction in the case that the phase-changing fault information is obtained and the main turn-off circuit cannot provide sufficient phase-changing voltage, and controlling the auxiliary turn-off circuit corresponding to the phase-changing bridge arm to be turned on based on the second circuit turn-on instruction, generating a second circuit turn-off instruction in the case that the first semi-controlled valve and / or the second semi-controlled valve of the phase-changing bridge arm of the main branch is recovered to be turned off, and controlling the auxiliary turn-off circuit to be turned off.

[0187] In some embodiments, the active phase-changing current transformer adopts a network construction control method, does not need to rely on a phase-locked loop, and can achieve voltage and frequency control through power current flow, including droop control, and / or virtual synchronous generator control, and / or virtual oscillator control.

[0188] In some embodiments, in the case that the active phase-changing current transformer further comprises an auxiliary turn-off circuit, the auxiliary turn-off circuit and the main branch anode bus and the main branch cathode bus of the active phase-changing current transformer are connected through a disconnector or / and a knife switch, and in the case of failure of the auxiliary turn-off circuit, the disconnector and / or the knife switch is disconnected.

[0189] In some embodiments, the third controllable valve only needs to provide a small off voltage to meet the commutation requirement in normal operation. The first controllable valve, the second controllable valve, the fourth controllable valve and the fifth controllable valve only act in the fault moment, need to provide a short overcurrent capacity and a large off voltage to cut off the fault current and provide a commutation voltage. When the first controllable valve, the second controllable valve, the fourth controllable valve and the fifth controllable valve are off, the current will be transferred to the parallel arrester, and the arrester provides the off voltage and absorbs the energy. Compared with the prior art, the present application has the advantages of continuously providing a certain commutation voltage, reducing the loss of reactive power, and if the first controllable valve, the second controllable valve, the fourth controllable valve and the fifth controllable valve are also configured in the circuit, the present application can provide sufficient commutation voltage in the fault moment, thereby inhibiting the occurrence of commutation failure.

[0190] In some embodiments, with reference to Figure 11 In the case where the off angle reference value is less than the minimum off angle setting value, taking the upper bridge arm circuit of the A phase of the main branch as an example, when the A phase upper bridge arm circuit commutates to the B phase upper bridge arm circuit, at this time, since the off angle reference value is set to be small, the first half-controlled valve V41 and the second half-controlled valve V42 of the A phase upper bridge arm circuit of the main branch will naturally fail to commutate, during the commutation period, the third half-controlled valve V43 of the A phase upper bridge arm transfer circuit of the auxiliary branch is controlled to be conductive, and the third controllable valve V410 of the A phase main off circuit is controlled to present a negative voltage; after the current is transferred from the second half-controlled valve V42 to the auxiliary branch, after the second half-controlled valve V42 of the A phase upper bridge arm circuit of the main branch is restored to be off, the first half-controlled valve V61 of the B phase upper bridge arm circuit and the third half-controlled valve V63 of the upper bridge arm transfer circuit are controlled to be conductive, the third controllable valve V630 of the B phase main off circuit is controlled to present a negative voltage relative to the upper bridge arm circuit, the third controllable valve V410 of the A phase main off circuit is controlled to be off and present a positive voltage, so that the current of the A phase upper bridge arm circuit is transferred to the B phase upper bridge arm circuit. Then, the second half-controlled valve V62 of the B phase upper bridge arm circuit is controlled to be conductive, and the third controllable valve V630 of the B phase main off circuit is controlled to be off.

[0191] In some embodiments, with reference to Figure 12 Taking the upper bridge arm circuit of the A phase of the main branch as an example, when the A phase upper bridge arm circuit commutates to the B phase upper bridge arm circuit, at this time, the fault may cause the first half-controlled valve V41 of the A phase upper bridge arm circuit of the main branch to fail to commutate, when the third controllable valve V410 of the A phase main off circuit is controlled to be off, the second controllable valve V43 is controlled to be off, so that the current of the A phase upper bridge arm circuit is transferred to the B phase upper bridge arm circuit.

[0192] In some embodiments, with reference to Figure 13For example, taking the A-phase upper bridge arm circuit of the main branch as an example, when the A-phase upper bridge arm circuit commutates to the B-phase upper bridge arm circuit, at this time, a fault may cause the first half-controlled valve V41 of the A-phase upper bridge arm circuit of the main branch to fail to commutate, and when the third fully-controlled valve V410 of the A-phase main turn-off circuit is controlled to be turned off, the fourth fully-controlled valve V71 and the fifth half-controlled valve V81 are controlled to be turned on, the current is transferred from the first half-controlled valve V41 to the auxiliary turn-off circuit, and the fourth fully-controlled valve V71 is controlled to be turned off, so that the current of the A-phase upper bridge arm circuit is transferred to the B-phase upper bridge arm circuit.

[0193] In some embodiments, with reference to Figure 14 For example, taking the A-phase upper bridge arm circuit of the main branch as an example, when the A-phase upper bridge arm circuit commutates to the B-phase upper bridge arm circuit, at this time, a fault may cause the first half-controlled valve V41 of the A-phase upper bridge arm circuit of the main branch to fail to commutate, and when the third fully-controlled valve V410 of the A-phase main turn-off circuit is controlled to be turned off, the fourth fully-controlled valve V71 and the fifth half-controlled valve V81 are controlled to be turned on, the current is transferred from the first half-controlled valve V41 to the auxiliary turn-off circuit, and the fourth fully-controlled valve V71 is controlled to be turned off, so that the current of the A-phase upper bridge arm circuit is transferred to the B-phase upper bridge arm circuit.

[0194] In some embodiments, with reference to Figure 15 For example, taking the A-phase upper bridge arm circuit of the main branch as an example, when the A-phase upper bridge arm circuit commutates to the B-phase upper bridge arm circuit, at this time, a fault may cause the first half-controlled valve V41 of the A-phase upper bridge arm circuit of the main branch to fail to commutate, and when the third fully-controlled valve V410 of the A-phase main turn-off circuit is controlled to be turned off, the fourth fully-controlled valve V71 and the fifth half-controlled valve V81 are controlled to be turned on, the current is transferred from the first half-controlled valve V41 to the auxiliary turn-off circuit, and the fourth fully-controlled valve V71 is controlled to be turned off, so that the current of the A-phase upper bridge arm circuit is transferred to the B-phase upper bridge arm circuit.

[0195] In some embodiments, with reference to Figure 16 For example, taking the A-phase upper bridge arm circuit of the main branch as an example, when the A-phase upper bridge arm circuit commutates to the B-phase upper bridge arm circuit, at this time, a fault may cause the first half-controlled valve V41 of the A-phase upper bridge arm circuit of the main branch to fail to commutate, and when the third fully-controlled valve V410 of the A-phase main turn-off circuit is controlled to be turned off, the fourth fully-controlled valve V71 and the fifth half-controlled valve V81 are controlled to be turned on, the current is transferred from the first half-controlled valve V41 to the auxiliary turn-off circuit, and the fourth fully-controlled valve V71 is controlled to be turned off, so that the current of the A-phase upper bridge arm circuit is transferred to the B-phase upper bridge arm circuit.

[0196] In some embodiments, with reference to Figure 17In the case that the turn-off angle reference value is less than the minimum turn-off angle setting value, taking the upper bridge arm circuit of phase A of the main branch as an example, when the upper bridge arm circuit of phase A commutates to the upper bridge arm circuit of phase B, at this time, the second half-controlled valve V42 of the upper bridge arm circuit of phase A of the main branch will fail to naturally commutate due to the small turn-off angle reference value. During commutation, the first fully-controlled valve V61 and the second half-controlled valve V62 of the upper bridge arm circuit of phase B are controlled to be turned on, the third fully-controlled valve V630 of the main turn-off circuit of phase B is controlled to present negative voltage to the upper bridge arm circuit, the third fully-controlled valve V410 of the main turn-off circuit of phase A is controlled to be turned off and present positive voltage, so that the current of the upper bridge arm circuit of phase A is transferred to the upper bridge arm circuit of phase B. If the failure occurs, the first fully-controlled valve V41 is controlled to be turned off when the third fully-controlled valve V410 of the main turn-off circuit of phase A is controlled to be turned off, so that the current of the upper bridge arm circuit of phase A is transferred to the upper bridge arm circuit of phase B.

[0197] In some embodiments, with reference to Figure 18 Taking the upper bridge arm circuit of phase A of the main branch as an example, when the upper bridge arm circuit of phase A commutates to the upper bridge arm circuit of phase B, at this time, the first half-controlled valve V41 of the upper bridge arm circuit of phase A of the main branch will fail to commutate due to the failure. When the third fully-controlled valve V410 of the main turn-off circuit of phase A is controlled to be turned off, the fourth fully-controlled valve V71 and the fifth half-controlled valve V81 are controlled to be turned on, the current is transferred from the first half-controlled valve V41 to the auxiliary turn-off circuit, and the fourth fully-controlled valve V71 is controlled to be turned off, so that the current of the upper bridge arm circuit of phase A is transferred to the upper bridge arm circuit of phase B.

[0198] In some embodiments, with reference to Figure 19 Taking the upper bridge arm circuit of phase A of the main branch as an example, when the upper bridge arm circuit of phase A commutates to the upper bridge arm circuit of phase B, at this time, the second half-controlled valve V42 of the upper bridge arm circuit of phase A of the main branch will fail to commutate due to the failure. When the third fully-controlled valve V410 of the main turn-off circuit of phase A is controlled to be turned off, the fifth fully-controlled valve V73 and the sixth half-controlled valve V83 are controlled to be turned on, the first half-controlled valve V11 of the lower bridge arm circuit of the main branch and the second half-controlled valve V12 of the lower bridge transfer circuit of the auxiliary branch are controlled to be turned on, and the first fully-controlled valve V41 of the upper bridge arm circuit is controlled to be turned off. The current is transferred from the second half-controlled valve V42 to the auxiliary turn-off circuit, and when the second half-controlled valve is turned off, the fifth fully-controlled valve V73 is controlled to be turned off, so that the current of the upper bridge arm circuit of phase A is transferred to the upper bridge arm circuit of phase B.

[0199] In some embodiments, with reference to Figure 21, control the main branch inverter operation, in the case of the turn-off angle reference value being less than the minimum turn-off angle setting value, control the main branch inverter operation, control the main turn-off circuit to be turned on and present a negative voltage to transfer current during commutation, after the second half-controlled valve of the commutation bridge arm recovers to be turned off, control the main turn-off circuit to be turned off to provide auxiliary commutation voltage, thereby reducing reactive power loss; in the case of judging that the main turn-off circuit cannot provide sufficient commutation voltage to cause the commutation bridge arm to fail to commutate, in the case of the active commutation converter including an auxiliary turn-off circuit, control the auxiliary turn-off circuit of the commutation bridge arm to be turned on to transfer current, after the first half-controlled valve and / or the second half-controlled valve of the commutation bridge arm recovers to be turned off, control the auxiliary turn-off circuit to be turned off, and complete the commutation process between the bridge arms.

[0200] With reference to Figure 22 , the active commutation converter control device 20 can specifically include: a first control module 201 and a second control module 202, wherein,

[0201] The first control module 201 is configured to, in the case of obtaining the operating parameter information of the active commutation converter, generate inverter state control information based on the parameter information, and control the main branch of the bridge arm circuit to operate in an inverter state based on the inverter state control information.

[0202] The second control module 202 is configured to, in the case of the active commutation converter including at least one phase unit and / or an auxiliary turn-off circuit, and in the case of obtaining a turn-off angle reference value being less than a minimum turn-off angle setting value or commutation failure information, generate a first circuit turn-on instruction and first negative voltage control information, control the transfer circuit in the auxiliary branch corresponding to the commutation bridge arm to be turned on based on the first circuit turn-on instruction, and control the main turn-off circuit of the auxiliary branch corresponding to the commutation bridge arm to present a negative voltage based on the first negative voltage control information; in the case of the second half-controlled valve of the commutation bridge arm of the main branch recovering to be turned off, generate a first circuit turn-off instruction, and control the main turn-off circuit of the auxiliary branch to be turned off.

[0203] In the case of the active commutation converter including the main branch and the main turn-off circuit of the auxiliary branch, and in the case of obtaining a turn-off angle reference value being less than a minimum turn-off angle setting value or commutation failure information, generate a first circuit turn-off instruction, and control the main turn-off circuit of the auxiliary branch to be turned off.

[0204] In some embodiments, the first control module 201 can include a logic circuit, or can be implemented by a central processor, a microprocessor, a digital signal processor, a field programmable gate array, or the like included in a device;

[0205] The second control module 202 can include a logic circuit, or can be implemented by a central processor, a microprocessor, a digital signal processor, a field programmable gate array, or the like included in a device.

[0206] This invention provides a high-voltage direct current transmission system, including an active phase-commutation converter.

[0207] In some embodiments, the high-voltage direct current transmission system is a two-terminal direct current transmission system or a multi-terminal direct current transmission system. The two-terminal direct current transmission system or the multi-terminal direct current transmission system respectively includes a unipolar direct current transmission system, a bipolar direct current transmission system or a back-to-back direct current system.

[0208] The active commutation converters mentioned above are used in some or all of the converters in two-terminal or multi-terminal DC transmission systems that require inverter operation.

[0209] Reference Figure 23 The diagram illustrates the structure of a single pole in a bipolar DC transmission system. A single pole includes a first AC system 12, a first grid-commutated converter 8, a second grid-commutated converter 9, a first converter transformer 10, a second converter transformer 11, a DC line 13, a second AC system 18, a first active phase-commutated converter 14, a second active phase-commutated converter 15, a third converter transformer 16, and a fourth converter transformer 17. During forward power transmission, the AC power from the first AC system 12, after passing through the first converter transformer 10 and the second converter transformer 11, is rectified into DC power by the first grid-commutated converter 8 and the second grid-commutated converter 9. This DC power is then transmitted through the DC line 13 to the first active phase-commutated converter 14 and the second active phase-commutated converter 15, where it is inverted back into AC power. After passing through the third converter transformer 16 and the fourth converter transformer 17, it is transmitted to the second AC system 18, thus realizing the transmission of DC power. The first active commutator 14 and the second active commutator 15 have the ability to suppress commutation failure, ensuring the reliability of DC power transmission.

[0210] The above are only some embodiments of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A phase unit, characterized in that, include: The main branch includes an upper bridge arm circuit and a lower bridge arm circuit; wherein the upper bridge arm circuit and the lower bridge arm circuit are connected in series, one end of the upper bridge arm circuit is connected to the anode bus of the main branch, and one end of the lower bridge arm circuit is connected to the cathode bus of the main branch. The auxiliary branch includes an upper bridge transfer circuit, a lower bridge transfer circuit, and a main shutdown circuit; wherein, one end of the upper bridge transfer circuit is connected to the upper bridge arm circuit, the other end of the upper bridge transfer circuit is connected to one end of the lower bridge transfer circuit and one end of the main shutdown circuit, the other end of the lower bridge transfer circuit is connected to the lower bridge arm circuit, and the other end of the main shutdown circuit is connected to the common point where the upper bridge arm circuit and the lower bridge arm circuit are connected in series; Wherein, the upper bridge arm circuit and the lower bridge arm circuit respectively include a first semi-controlled valve and / or a first fully controlled valve and a second semi-controlled valve; the upper bridge transfer circuit and the lower bridge transfer circuit respectively include a third semi-controlled valve and / or a second fully controlled valve; the main shutdown circuit includes a third fully controlled valve; One end of the first semi-controlled valve and / or the first fully controlled valve of the upper bridge arm circuit is connected to the main branch anode bus. The other end of the first semi-controlled valve and / or the first fully controlled valve of the upper bridge arm circuit is connected to one end of the second semi-controlled valve and one end of the third semi-controlled valve and / or the second fully controlled valve of the upper bridge transfer circuit. The other end of the second semi-controlled valve of the upper bridge arm circuit is connected to one end of the third fully controlled valve of the main shutdown circuit. The other end of the third fully controlled valve of the main shutdown circuit is connected to the other end of the third semi-controlled valve and / or the second fully controlled valve of the upper bridge transfer circuit. One end of the first semi-controlled valve and / or the first fully controlled valve of the lower bridge arm circuit is connected to the cathode bus of the main branch. The other end of the first semi-controlled valve and / or the first fully controlled valve of the lower bridge arm circuit is connected to one end of the second semi-controlled valve and one end of the third semi-controlled valve and / or the second fully controlled valve of the lower bridge transfer circuit. The other end of the second semi-controlled valve of the lower bridge arm circuit is connected to one end of the third fully controlled valve of the main shutdown circuit. The other end of the third fully controlled valve of the main shutdown circuit is connected to the other end of the third semi-controlled valve and / or the second fully controlled valve of the lower bridge transfer circuit.

2. The phase unit according to claim 1, characterized in that, The first semi-controlled valve and / or the first fully controlled valve, and / or the second semi-controlled valve, and / or the third semi-controlled valve and / or the second fully controlled valve, and / or the third fully controlled valve are connected in parallel with surge arresters.

3. The phase unit according to claim 1, characterized in that, The first semi-controlled valve, the second semi-controlled valve, and the third semi-controlled valve include at least one of a one-way semi-controlled switch and a two-way semi-controlled switch; the first fully controlled valve and the second fully controlled valve include at least one of a one-way fully controlled switch, a two-way fully controlled switch, and a sub-module series switch; the third fully controlled valve includes at least one of a two-way fully controlled switch and a sub-module series switch.

4. The phase unit according to claim 3, characterized in that, The unidirectional semi-controlled switch is composed of semiconductor devices that can be controlled to turn on but not controlled to turn off, and the semiconductor devices that can be controlled to turn on but not controlled to turn off include, but are not limited to, thyristors. The bidirectional semi-controlled switch is composed of semiconductor devices that can be controlled to turn on but not controlled to turn off connected in antiparallel and then in series. The semiconductor devices that can be controlled to turn on but not controlled to turn off include, but are not limited to, thyristors. The unidirectional fully controlled switch is composed of semiconductor devices with unidirectional turn-off capability connected in series. The semiconductor devices with unidirectional turn-off capability include, but are not limited to, insulated gate bipolar transistors and integrated gate commutated thyristors. The bidirectional fully controlled switch is composed of semiconductor devices with bidirectional turn-off capability connected in series. The semiconductor devices with bidirectional turn-off capability include, but are not limited to, anti-parallel reverse-resistance integrated gate commutated thyristors and anti-connected insulated gate bipolar transistor modules. The sub-module series switch is composed of sub-modules connected in series. The sub-modules include, but are not limited to, half-bridge sub-modules, full-bridge sub-modules, near-full-bridge sub-modules, and clamped double sub-modules. The switching devices of the half-bridge sub-modules, full-bridge sub-modules, near-full-bridge sub-modules, or clamped double sub-modules include, but are not limited to, insulated-gate bipolar transistors and integrated gate commutated thyristors.

5. The phase unit according to any one of claims 1-4, characterized in that, The main shutdown circuit also includes a fourth semi-controlled valve, which is connected in parallel with the third fully controlled valve; the fourth semi-controlled valve includes at least one of a one-way semi-controlled switch and a two-way semi-controlled switch.

6. An active commutator converter, characterized in that, include: At least one phase unit as described in any one of claims 1-5; or, At least one phase unit and auxiliary shutdown circuit as described in any one of claims 1-5; or, At least one main branch and at least one auxiliary branch of the phase unit according to any one of claims 1-5 have main shutdown circuits; wherein one end of the main shutdown circuit of at least one auxiliary branch serves as a phase output terminal, and the other end of the main shutdown circuit of at least one auxiliary branch is connected to a common point where the upper arm circuit and the lower arm circuit of at least one main branch are connected in series, and the upper arm circuit and the lower arm circuit of at least one main branch each include a first full control valve; or, At least one main branch in the phase unit according to any one of claims 1-5, at least one auxiliary branch in the phase unit according to any one of claims 1-5, a main shutdown circuit and an auxiliary shutdown circuit; wherein, one end of the main shutdown circuit of at least one auxiliary branch serves as a phase output terminal, and the other end of the main shutdown circuit of at least one auxiliary branch is connected to a common point where the upper bridge arm circuit and the lower bridge arm circuit of at least one main branch are connected in series. The circuit constructed by the auxiliary shutdown circuit is connected in parallel with the circuit constructed by at least one upper or lower bridge arm circuit of the main branch and at least one main shutdown circuit of the auxiliary branch; or, the auxiliary shutdown circuit is connected in parallel with at least one phase unit.

7. The active commutator converter according to claim 6, characterized in that, The main branch anode bus is the positive input terminal, one end of the main shutdown circuit of the auxiliary branch is the phase output terminal, and the main branch cathode bus is the negative input terminal.

8. The active commutated converter according to claim 6, characterized in that, One end of the auxiliary shutdown circuit is connected to the main branch anode bus of the active commutation converter, and the other end of the auxiliary shutdown circuit is connected to the main branch cathode bus of the active commutation converter.

9. The active commutated converter according to claim 6, characterized in that, The auxiliary shutdown circuit is connected to the main branch anode bus and the main branch cathode bus of the active commutation converter via a disconnecting switch and / or a knife switch.

10. The active commutator according to any one of claims 6-9, characterized in that, When the circuit constructed by the auxiliary shutdown circuit is connected in parallel with at least one upper or lower bridge arm circuit of the main branch and at least one main shutdown circuit of the auxiliary branch, the auxiliary shutdown circuit includes a fourth full control valve. Alternatively, the auxiliary shutdown circuit includes a fourth fully controlled valve and a fifth partially controlled valve; the fourth fully controlled valve and the fifth partially controlled valve are connected in series; or... When the auxiliary shutdown circuit is connected in parallel with the at least one phase unit, the auxiliary shutdown circuit includes a fifth full control valve; Alternatively, the auxiliary shutdown circuit includes a fifth full control valve and a sixth semi control valve; the fifth full control valve and the sixth semi control valve are connected in series.

11. The active commutator converter according to claim 10, characterized in that, When the circuit constructed by the auxiliary shutdown circuit is connected in parallel with the circuit constructed by at least one upper or lower bridge arm circuit of the main branch and at least one main shutdown circuit of the auxiliary branch, the auxiliary shutdown circuit further includes a seventh semi-controlled valve or a first uncontrolled valve; the seventh semi-controlled valve or the first uncontrolled valve, the fourth fully controlled valve and the fifth semi-controlled valve are connected in series, and the circuit after series connection is connected in parallel with the upper or lower bridge arm circuit; or, the circuit after series connection is connected in parallel with the circuit in series connected with the upper or lower bridge arm circuit and at least one main shutdown circuit of the auxiliary branch.

12. The active commutator converter according to claim 10, characterized in that, When the auxiliary shutdown circuit is connected in parallel with the at least one phase unit, the first semi-controlled valve and the second semi-controlled valve include bidirectional semi-controlled switches.

13. The active commutator converter according to claim 10, characterized in that, When the circuit constructed by the auxiliary shutdown circuit is connected in parallel with at least one upper or lower bridge arm circuit of the main branch and at least one main shutdown circuit of the auxiliary branch, the upper bridge arm circuit and / or the lower bridge arm circuit share the fourth full control valve and / or the fifth half control valve of the auxiliary shutdown circuit. When the auxiliary shutdown circuit is connected in parallel with the at least one phase unit, the upper bridge arm circuit and the lower bridge arm circuit share the fifth full control valve and / or the sixth semi control valve of the auxiliary shutdown circuit.

14. The active commutator converter according to claim 10, characterized in that, The fifth and sixth semi-controlled valves include one-way semi-controlled switches, and the fourth and fifth fully controlled valves include at least one of one-way fully controlled switches, two-way fully controlled switches, and sub-module series switches. The first uncontrolled valve in the auxiliary shutdown circuit includes an uncontrolled switch. The uncontrolled switch is composed of semiconductor devices that cannot be controlled to turn on or off in series, and the semiconductor devices that cannot be controlled to turn on or off include, but are not limited to, diodes.

15. The active commutator converter according to claim 10, characterized in that, The fifth semi-control valve, and / or the fourth full control valve, and / or the fifth full control valve, and / or the sixth semi-control valve are connected in parallel with surge arresters.

16. A control method for an active commutated converter, characterized in that, Controlling the active commutator according to any one of claims 6-15, comprising: Upon obtaining the operating parameter information of the active commutation converter, inverter state control information is generated based on the operating parameter information, and the main branch is controlled to operate in inverter state based on the inverter state control information. When the active commutation converter includes at least one phase unit and / or an auxiliary shutdown circuit, and the active commutation converter shutdown angle reference value is less than the minimum shutdown angle setting or commutation fault information is obtained, a first circuit turn-on command and a first negative pressure control information are generated. Based on the first circuit turn-on command, the transfer circuit in the auxiliary branch corresponding to the commutation bridge arm of the main branch is turned on, and based on the first negative pressure control information, the main shutdown circuit of the auxiliary branch corresponding to the commutation bridge arm is controlled to present a negative pressure. When the second half-control valve of the commutation bridge arm of the main branch is restored to shutdown, a first circuit shutdown command is generated to control the main shutdown circuit of the auxiliary branch to shut down. Alternatively, when the active commutation converter includes the main branch and the main shutdown circuit of the auxiliary branch, and the active commutation converter shutdown angle reference value is less than the minimum shutdown angle setting or commutation fault information is obtained, a first circuit shutdown command is generated to control the main shutdown circuit of the auxiliary branch to shut down.

17. The method according to claim 16, characterized in that, When the active commutator is operating normally, the cut-off angle reference value is set to be less than the minimum cut-off angle set value. When the cut-off angle reference value is found to be less than the minimum cut-off angle set value and the second half-control valve of the commutation bridge arm of the main branch is restored to shut off, a first circuit shutdown command is generated to control the third full control valve corresponding to the commutation bridge arm to shut off.

18. The method according to claim 16, characterized in that, Before the main shutdown circuit of the auxiliary branch is turned off, a second negative pressure control information is generated, and the main shutdown circuit of the auxiliary branch corresponding to the bridge arm to be switched on is controlled to present a negative pressure based on the second negative pressure control information.

19. The method according to claim 16, characterized in that, When the capacitor voltage of the submodule of the third fully controlled valve in the main shutdown circuit is lower than the rated value and exceeds the first threshold, and the second half-controlled valve of the commutation bridge arm of the main branch resumes shutdown, a first circuit shutdown command is generated in advance; or / and the number of submodules of the third fully controlled valve in the main shutdown circuit is increased; or / and a first circuit conduction command and a first negative pressure control information are generated in advance; the first threshold value ranges from 0.01 to 0.6 times the rated capacitor voltage.

20. The method according to claim 16, characterized in that, If the capacitor voltage of the submodule of the third fully controlled valve in the main shutdown circuit is greater than or equal to the rated value and exceeds the second threshold, and the second half-controlled valve of the commutation bridge arm of the main branch resumes shutdown, the generation of the first circuit shutdown command is delayed; or / and the number of submodules of the third fully controlled valve in the main shutdown circuit is reduced; or / and the generation of the first circuit conduction command and the first negative pressure control information is delayed; the second threshold value ranges from 0.01 to 0.6 times the rated capacitor voltage.

21. The method according to claim 16, characterized in that, The negative voltage in the main shutdown circuit is achieved by controlling the switching device in the submodule of the third full control valve to conduct, causing the submodule to exhibit a capacitor negative voltage in the direction of current flow.

22. The method according to claim 16, characterized in that, The shutdown of the second half-controlled valve of the commutation bridge arm of the main branch is determined based on the reverse recovery time of the second half-controlled valve, wherein the reverse recovery time is greater than or equal to the reverse recovery time of the thyristor contained in the second half-controlled valve.

23. The method according to claim 16, characterized in that, In the event of overpressure or failure of the third full control valve in the main shutdown circuit, the second half control valve of the same phase unit as the third full control valve or the fourth half control valve of the main shutdown circuit is turned on.

24. The method according to claim 16, characterized in that, The method further includes: The upper arm circuit and the lower arm circuit each include a first full control valve. When commutation fault information is obtained and the main shutdown circuit cannot provide sufficient commutation voltage, a second circuit shutdown command is generated, and the first full control valve is controlled to shut down based on the second circuit shutdown command.

25. The method according to claim 16, characterized in that, When the upper bridge transfer circuit and the lower bridge transfer circuit each include a second fully controlled valve, the method further includes: If a commutation fault is detected and the main shutdown circuit cannot provide sufficient commutation voltage, a third circuit shutdown command is generated, and the second full control valve is shut off based on the third circuit shutdown command.

26. The method according to claim 16, characterized in that, When the active commutator further includes an auxiliary shutdown circuit, the method further includes: When a commutation fault is detected and the main shutdown circuit cannot provide sufficient commutation voltage, a second circuit turn-on command is generated. Based on the second circuit turn-on command, the auxiliary shutdown circuit corresponding to the commutation bridge arm is turned on. When the first half-control valve and / or the second half-control valve of the commutation bridge arm of the main branch is turned off, a fourth circuit turn-off command is generated to control the auxiliary shutdown circuit to turn off.

27. The method according to claim 16, characterized in that, The active commutation converter uses a grid control method to control voltage and frequency.

28. The method according to any one of claims 16-27, characterized in that, In the case where the active commutation converter also includes an auxiliary shutdown circuit, the auxiliary shutdown circuit is connected to the main branch anode bus and the main branch cathode bus of the active commutation converter through a disconnecting switch and / or a knife switch, and in the event of a failure of the auxiliary shutdown circuit, the disconnecting switch and / or the knife switch is disconnected.

29. A control device for an active commutator converter, characterized in that, Controlling the active commutator according to any one of claims 6-15, comprising: The first control module is used to generate inverter state control information based on the operating parameter information of the active commutation converter, and control the main branch to operate in inverter state based on the inverter state control information. The second control module is configured to generate a first circuit turn-on command and first negative pressure control information when the active commutation converter includes at least one phase unit and / or an auxiliary shutdown circuit, and the active commutation converter shutdown angle reference value is less than the minimum shutdown angle setting or commutation fault information is obtained; and based on the first circuit turn-on command, control the transfer circuit in the auxiliary branch corresponding to the commutation bridge arm of the main branch to turn on, and based on the first negative pressure control information, control the main shutdown circuit of the auxiliary branch corresponding to the commutation bridge arm to present negative pressure; generate a first circuit shutdown command when the second half-control valve of the commutation bridge arm of the main branch resumes shutdown, and control the main shutdown circuit of the auxiliary branch to shut down; or, when the active commutation converter includes the main branch and the main shutdown circuit of the auxiliary branch, and the active commutation converter shutdown angle reference value is less than the minimum shutdown angle setting or commutation fault information is obtained, generate a first circuit shutdown command and control the main shutdown circuit of the auxiliary branch to shut down.

30. A high-voltage direct current transmission system, comprising the active phase-commutated converter as described in any one of claims 6-15.

31. The system according to claim 30, characterized in that, The high-voltage direct current transmission system is a two-terminal direct current transmission system or a multi-terminal direct current transmission system. The two-terminal direct current transmission system or the multi-terminal direct current transmission system includes a unipolar direct current transmission system, a bipolar direct current transmission system, or a back-to-back direct current transmission system.

32. The system according to claim 31, characterized in that, The active commutation converter is used in some or all of the converters in the two-terminal or multi-terminal DC transmission system that require inverter operation.

Images