Full-bridge circuit turn-off grid commutation converter and control method, device and system thereof

Abstract

The invention provides a full-bridge circuit turn-off power grid commutation converter and a control method, device and system thereof, and relates to the technical field of high-voltage direct-current power transmission. The full-bridge circuit turn-off grid commutation converter comprises at least one phase of upper bridge arm circuit, at least one phase of lower bridge arm circuit, at least one phase of upper bridge transfer circuit, an upper bridge turn-off circuit, an upper bridge full-bridge circuit, at least one phase of lower bridge transfer circuit, a lower bridge turn-off circuit and a lower bridge full-bridge circuit. The upper bridge turn-off circuit is connected in series with the upper bridge full-bridge circuit, and one end of the serially connected circuit is connected with an anode bus of the upper bridge transfer circuit; the lower bridge turn-off circuit and the lower bridge full-bridge circuit are connected in series, and one end of the circuit after series connection is connected with a cathode bus of the lower bridge transfer circuit. The method has the effects of inhibiting commutation failure, improving high-voltage direct-current transmission reliability, reducing a turn-off angle reference value and reducing reactive power consumed by the converter.

Description

Technical Field

[0001] The present invention relates to the technical field of high voltage direct current transmission, and in particular to a full-bridge circuit shut-down grid commutation converter and a control method, device and system thereof. Background Art

[0002] With the increasing number of high-voltage and ultra-high-voltage direct current transmission systems connected, multi-input direct current transmission systems have been formed in many regional power grids. When multiple direct current lines fail to commutate at the same time, it may pose a threat to the safe operation of the alternating current power grid in the region. In addition, as the proportion of renewable energy power generation increases, the AC voltage support capacity decreases, which puts higher requirements on the stable operation of the direct current transmission system and the ability to suppress commutation failures.

[0003] The existing DC transmission technology mainly adopts a grid-commutated converter with a twelve-pulse circuit structure and a voltage source converter with a modular multi-level circuit structure for high-voltage and ultra-high-voltage DC transmission. In the grid-commutated converter with a twelve-pulse circuit structure, each twelve-pulse circuit is composed of two three-phase six-bridge arm bridge circuits connected in series or in parallel, and each bridge arm adopts a single large-capacity thyristor in series; in the voltage source converter with a modular multi-level circuit structure, the modular multi-level circuit is a three-phase six-bridge arm bridge circuit, and each bridge arm adopts a half-bridge sub-module structure and / or a full-bridge sub-module structure in series. In addition, it has become an important research direction of DC transmission technology to solve the commutation failure problem by replacing the existing grid-commutated converter with fully controlled devices and adding auxiliary circuits to form a controllably shut-down grid-commutated converter.

[0004] However, the existing grid-commutated converter with a twelve-pulse circuit structure has the problem of commutation failure; the existing voltage source converter with a modular multi-level circuit structure has the problems of small device capacity, high cost and large loss. The existing controllable shutdown grid-commutated converter that uses full-control device replacement to suppress commutation failure has a small device capacity and its reliability needs to be verified; the existing controllable shutdown grid-commutated converter that suppresses commutation failure by adding auxiliary circuits has a complex structure and reduced reliability; the above two controllable shutdown grid-commutated converters rely on lightning arresters to absorb energy when forced to shut down, and each bridge arm needs to be equipped with an equal amount of lightning arresters. In the case of a high probability fault such as single-phase grounding, only the lightning arrester of the fault phase will be activated, resulting in a low utilization rate of the lightning arrester. Since the lightning arrester can only absorb energy for a short time, the lightning arrester cannot be activated during steady-state operation, so it still needs to rely on the AC system voltage for commutation, resulting in the minimum shutdown angle cannot be controlled too small, and still requires more reactive power consumption. Summary of the invention

[0005] In order to suppress the occurrence of commutation failure, reduce the cost of controllably shut down grid commutation converters, improve the reliability of high-voltage direct current transmission, reduce the shutdown angle reference value, and reduce the reactive power consumption, the present invention provides a full-bridge circuit shutdown grid commutation converter and a control method, device, and system thereof.

[0006] The present invention provides a full-bridge circuit shutting down a grid commutation converter, which adopts the following technical solution:

[0007] A full-bridge circuit shuts down a grid-commutated converter, comprising:

[0008] A main circuit, comprising at least one-phase upper bridge arm circuit and at least one-phase lower bridge arm circuit, wherein one end of the at least one-phase upper bridge arm circuit is connected to the anode bus of the main circuit, the other end of the at least one-phase upper bridge arm circuit is connected to one end of the at least one-phase lower bridge arm circuit, and the other end of the at least one-phase lower bridge arm circuit is connected to the cathode bus of the main circuit;

[0009] an auxiliary circuit, comprising at least one phase upper bridge transfer circuit, an upper bridge shutdown circuit, an upper bridge full-bridge circuit, at least one phase lower bridge transfer circuit, a lower bridge shutdown circuit, and a lower bridge full-bridge circuit;

[0010] One end of the at least one-phase upper bridge transfer circuit is connected to the upper bridge transfer circuit anode bus, the other end of the at least one-phase upper bridge transfer circuit is connected to the at least one-phase upper bridge arm circuit, the upper bridge shutdown circuit is connected in series with the upper bridge full-bridge circuit, and one end of the series-connected circuit is connected to the upper bridge transfer circuit anode bus, and the other end is connected to the main circuit anode bus;

[0011] One end of the at least one-phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end of the at least one-phase lower bridge transfer circuit is connected to the at least one-phase lower bridge arm circuit. The lower bridge shutdown circuit is connected in series with the lower bridge full-bridge circuit, and one end of the series-connected circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end is connected to the cathode bus of the main circuit.

[0012] According to some embodiments, the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include: a first half-controlled valve and / or a second half-controlled valve;

[0013] In the case where both the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve and a second half-controlled valve, the first half-controlled valve and the second half-controlled valve are connected in series; one end of the first half-controlled valve of the at least one-phase upper bridge arm circuit is connected to the anode bus of the main circuit, and one end of the second half-controlled valve of the at least one-phase upper bridge arm circuit is connected to one end of the second half-controlled valve of the at least one-phase lower bridge arm circuit; one end of the first half-controlled valve of the at least one-phase lower bridge arm circuit is connected to the cathode bus of the main circuit; or,

[0014] In the case where the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve, one end of the first half-controlled valve of the at least one-phase upper bridge arm circuit is connected to the anode bus of the main circuit, and the other end of the first half-controlled valve of the at least one-phase upper bridge arm circuit is connected to one end of the first half-controlled valve of the at least one-phase lower bridge arm circuit; the other end of the first half-controlled valve of the at least one-phase lower bridge arm circuit is connected to the cathode bus of the main circuit.

[0015] According to some embodiments, the at least one phase upper bridge transfer circuit and the at least one phase lower bridge transfer circuit each include: a third half-controlled valve or a first uncontrolled valve;

[0016] In the case where the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve and a second half-controlled valve, one end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase upper bridge transfer circuit is connected to the anode bus of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase upper bridge transfer circuit is connected to the connection point between the first half-controlled valve and the second half-controlled valve of the at least one-phase upper bridge arm circuit; one end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase lower bridge transfer circuit is connected to the connection point between the first half-controlled valve and the second half-controlled valve of the at least one-phase lower bridge arm circuit; or,

[0017] In the case where the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve, one end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase upper bridge transfer circuit is connected to the anode bus of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase upper bridge transfer circuit is connected to one end of the first half-controlled valve of the at least one-phase upper bridge arm circuit; one end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase lower bridge transfer circuit is connected to one end of the first half-controlled valve of the at least one-phase lower bridge arm circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit.

[0018] According to some embodiments, the first half-controlled valve, the second half-controlled valve and the third half-controlled valve each include a half-controlled switch; the first uncontrolled valve includes an uncontrolled switch;

[0019] The half-controlled switch is composed of semiconductor devices that can be controlled to be turned on but not controlled to be turned off connected in series, and the semiconductor devices that can be controlled to be turned on but not controlled to be turned off include but are not limited to thyristors; the uncontrolled switch is composed of semiconductor devices that can be turned on and off uncontrollably connected in series, and the semiconductor devices that can be turned on and off uncontrollably include but are not limited to diodes.

[0020] According to some embodiments, the first half-controlled valve, and / or the second half-controlled valve, and / or the third half-controlled valve or the first uncontrolled valve are all connected in parallel with a lightning arrester.

[0021] According to some embodiments, when the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve and a second half-controlled valve, a withstand voltage ratio of the first half-controlled valve and the second half-controlled valve ranges from 0.2 to 5.

[0022] According to some embodiments, the first half-controlled valve, and / or the second half-controlled valve, and / or the third half-controlled valve or the first uncontrolled valve further includes a reactor.

[0023] According to some embodiments, the circuit in which the upper bridge shutdown circuit of the auxiliary circuit is connected in series with the upper bridge full-bridge circuit and the anode bus of the main circuit are connected via an isolating switch or a knife switch; the circuit in which the lower bridge shutdown circuit of the auxiliary circuit is connected in series with the lower bridge full-bridge circuit and the cathode bus of the main circuit are connected via an isolating switch or a knife switch.

[0024] According to some embodiments, the upper bridge shutoff circuit and the lower bridge shutoff circuit each include a first fully controlled valve;

[0025] One end of the first full-control valve of the upper bridge shut-off circuit is connected to one end of the upper bridge full-bridge circuit, and the other end of the first full-control valve of the upper bridge shut-off circuit is connected to the anode bus of the upper bridge transfer circuit; or, one end of the first full-control valve of the upper bridge shut-off circuit is connected to one end of the upper bridge full-bridge circuit, and the other end of the first full-control valve of the upper bridge shut-off circuit is connected to the anode bus of the main circuit;

[0026] One end of the first full-control valve of the lower bridge shutdown circuit is connected to one end of the lower bridge full-bridge circuit, and the other end of the first full-control valve of the lower bridge shutdown circuit is connected to the cathode bus of the lower bridge transfer circuit; or, one end of the first full-control valve of the lower bridge shutdown circuit is connected to one end of the lower bridge full-bridge circuit, and the other end of the first full-control valve of the lower bridge shutdown circuit is connected to the cathode bus of the main circuit.

[0027] According to some embodiments, the upper bridge shutoff circuit and the lower bridge shutoff circuit each further include a fourth half-controlled valve connected in series with the first full-controlled valve.

[0028] According to some embodiments, a lightning arrester is connected in parallel to the first full-control valve.

[0029] According to some embodiments, the first full-control valve includes at least one of a one-way full-control switch, a two-way full-control switch, and a sub-module series switch.

[0030] According to some embodiments, 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, integrated gate-commutated thyristors, and reverse-blocking integrated gate-commutated thyristors;

[0031] The bidirectional fully-controlled switch is composed of semiconductor devices with bidirectional shutoff capability connected in series, and the semiconductor devices with bidirectional shutoff capability include but are not limited to anti-parallel reverse-resistance integrated gate-commutated thyristors and anti-series insulated gate bipolar transistors;

[0032] 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 twin submodules. The semiconductor devices of the half-bridge submodules, full-bridge submodules, quasi-full-bridge submodules, and clamped twin submodules include but are not limited to insulated gate bipolar transistors and integrated gate-commutated thyristors.

[0033] According to some embodiments, the upper bridge full-bridge circuit and the lower bridge full-bridge circuit both include: a second fully-controlled valve; one end of the second fully-controlled valve of the upper bridge full-bridge circuit is connected to the anode bus of the main circuit, and the other end of the second fully-controlled valve of the upper bridge full-bridge circuit is connected to the upper bridge shut-off circuit; or, one end of the second fully-controlled valve of the upper bridge full-bridge circuit is connected to the anode bus of the upper bridge transfer circuit, and the other end of the second fully-controlled valve of the upper bridge full-bridge circuit is connected to the upper bridge shut-off circuit;

[0034] One end of the second full-controlled valve of the lower bridge full-bridge circuit is connected to the cathode bus of the main circuit, and the other end of the second full-controlled valve of the lower bridge full-bridge circuit is connected to the lower bridge shutdown circuit; or, one end of the second full-controlled valve of the lower bridge full-bridge circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end of the second full-controlled valve of the lower bridge full-bridge circuit is connected to the lower bridge shutdown circuit.

[0035] According to some embodiments, the second fully-controlled valve includes at least one of a full-bridge sub-module connected in series, a quasi-full-bridge sub-module, a midpoint clamped sub-module, a dual half-bridge series sub-module, a dual full-bridge series sub-module, a clamped twin sub-module, a cross-connected twin sub-module, a self-resistance sub-module or a diode clamped sub-module.

[0036] According to some embodiments, the upper full-bridge circuit and the lower full-bridge circuit further include a resistor or an inductor; and the resistor or the inductor is connected in series with the submodule.

[0037] According to some embodiments, a lightning arrester is connected in parallel to the second full-control valve.

[0038] During normal operation, if the full-bridge circuit is used to provide continuous commutation voltage, the higher the turn-off voltage of the full-bridge circuit, the smaller the turn-off angle of the full-bridge circuit that can be set to turn off the grid commutation converter, and the less reactive power consumption. In the event of a commutation fault, the shutdown circuit provides an instantaneous commutation voltage. Therefore, the turn-off voltage of the full-bridge circuit is lower than that of the shutdown circuit, and the ratio of the two turn-off voltages ranges from 0.01 to 0.5.

[0039] The present invention provides a control method for shutting down a grid phase-commutation converter by a full-bridge circuit, which adopts the following technical solution:

[0040] A full-bridge circuit shuts down a grid-commutating converter control method, which is used to control the full-bridge circuit shuts down a grid-commutating converter, comprising:

[0041] In the case of obtaining the operation parameter information of the full-bridge circuit shutting down the grid-commutated converter, generating the inverter state control information based on the parameter information, and controlling the main circuit to operate in the inverter state based on the inverter state control information;

[0042] When the turn-off angle reference value is less than the minimum turn-off angle setting value or the commutation fault information is obtained, a circuit conduction instruction and negative voltage control information are generated during the commutation period, and the transfer circuit and the turn-off circuit in the auxiliary circuit corresponding to the commutation bridge arm are controlled to be turned on based on the circuit conduction instruction, and the full bridge circuit of the auxiliary circuit corresponding to the commutation bridge arm is controlled to present a negative voltage based on the negative voltage control information;

[0043] When the first half-controlled valve of the commutation bridge arm of the main circuit is restored to be closed, a circuit closing instruction is generated to control the full-bridge circuit and / or the shut-off circuit corresponding to the commutation bridge arm to be shut down.

[0044] According to some embodiments, when the full-bridge circuit is shut down and the grid-commutating converter is operating normally, the shutdown angle reference value is set to be less than the minimum shutdown angle setting; when the shutdown angle reference value is obtained to be less than the minimum shutdown angle setting and the first half-controlled valve of the commutating bridge arm of the main circuit is restored to shutdown, the circuit shutdown instruction is generated, and based on the circuit shutdown instruction, only the full-bridge circuit corresponding to the commutating bridge arm is controlled to be shut down.

[0045] According to some embodiments, when the capacitor voltage of the sub-module of the full-bridge circuit of the auxiliary circuit is lower than the rated value and exceeds the first threshold value, and the first half-controlled valve of the commutation bridge arm of the main circuit resumes shutdown, the circuit shutdown instruction is generated in advance; and / or the number of sub-modules of the full-bridge circuit is increased; and / or the circuit conduction instruction for controlling the conduction of the corresponding transfer circuit and the shutdown circuit and the negative pressure control information for controlling the sub-module of the full-bridge circuit to present negative pressure are generated in advance; the value range of the first threshold value is 0.01 to 0.6 times the rated capacitor voltage.

[0046] Optionally, when the sub-module capacitor voltage is greater than or equal to the rated value and exceeds the second threshold, and when the first half-controlled valve of the phase-changing bridge arm of the main circuit resumes shutdown, the generation of the circuit shutdown instruction is delayed; and / or the number of sub-modules of the full-bridge circuit is reduced; and / or the generation of the circuit conduction instruction for controlling the conduction of the corresponding transfer circuit and the shutdown circuit and the negative pressure control information for controlling the sub-module of the full-bridge circuit to present negative pressure is delayed; the second threshold value range is 0.01 to 0.6 times the rated capacitor voltage.

[0047] According to some embodiments, controlling the full-bridge circuit to present a negative pressure is achieved by controlling a switch device in a submodule of the third fully-controlled valve to be turned on so that the submodule presents a capacitive negative pressure in a current flow direction.

[0048] According to some embodiments, the recovery and shutdown of the first half-controlled valve of the commutation bridge arm of the main circuit is determined based on the reverse recovery time of the first half-controlled valve, and the reverse recovery time is greater than or equal to the reverse recovery time of the thyristor included in the first half-controlled valve.

[0049] According to some embodiments, the circuit after the upper bridge shutdown circuit of the auxiliary circuit is connected in series with the upper bridge full-bridge circuit and the anode bus of the main circuit are connected via an isolating switch or a knife switch, the circuit after the lower bridge shutdown circuit of the auxiliary circuit is connected in series with the lower bridge full-bridge circuit and the cathode bus of the main circuit are connected via an isolating switch and / or a knife switch, and a switch separation instruction is generated when the fault information of the auxiliary circuit is obtained, and the isolating switch or knife switch is controlled to separate based on the switch separation instruction.

[0050] The present invention provides a full-bridge circuit shut-down grid commutation converter control device, which adopts the following technical solution:

[0051] A full-bridge circuit shut-off grid-commutation converter control device is used to control the full-bridge circuit shut-off grid-commutation converter, comprising: a first control module, a second control module and a third control module, wherein:

[0052] A first control module is used to generate inverter state control information based on the parameter information when the operation parameter information of the full-bridge circuit shutting down the grid-commutated converter is obtained, and control the main circuit to operate in the inverter state based on the inverter state control information;

[0053] a second control module, for generating a circuit conduction instruction and negative voltage control information during the commutation period when the turn-off angle reference value is less than the minimum turn-off angle setting value or the commutation fault information is obtained, and controlling the transfer circuit and the turn-off circuit in the auxiliary circuit corresponding to the commutation bridge arm to be turned on based on the circuit conduction instruction, and controlling the full bridge circuit of the auxiliary circuit corresponding to the commutation bridge arm to present a negative voltage based on the negative voltage control information;

[0054] The third control module is used to generate a circuit shutdown instruction to control the full-bridge circuit and / or shutdown circuit corresponding to the phase-changing bridge arm to shut down when the first half-controlled valve included in the phase-changing bridge arm of the main circuit resumes shutdown.

[0055] The present invention provides a high-voltage direct current power transmission system, comprising the full-bridge circuit shut-off grid commutation converter.

[0056] According to 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, and the two-terminal direct current transmission system includes a monopolar direct current transmission system, a bipolar direct current transmission system or a back-to-back direct current system.

[0057] According to some embodiments, the two-terminal DC power transmission system or the multi-terminal DC power transmission system partially or completely uses the full-bridge circuit to shut down the grid-commutated converter for the converter that needs to be inverted.

[0058] In summary, the present invention includes the following beneficial technical effects:

[0059] When a commutation failure may occur due to a fault in the AC system, the full-bridge circuit of the control auxiliary circuit presents a negative voltage, the corresponding transfer circuit and the shut-off circuit are turned on to form a flow in parallel with the commutation bridge arm of the main circuit, and the current is transferred to the auxiliary circuit. After the first half-controlled valve of the commutation bridge arm of the main circuit is restored and shut down, the full-bridge circuit and / or the shut-off circuit of the control auxiliary circuit are shut down to realize the shut-off of the commutation bridge arm, effectively suppress the occurrence of commutation failure, and realize the controllable shut-off of the full-bridge circuit to shut down the grid commutation converter; at the same time, the continuous shut-off capability of the full-bridge circuit can be used to reduce the shut-off angle reference value and reduce the reactive power consumption. Compared with the prior art, the circuit structure of the present invention is simple, the reactive compensation equipment can be reduced, the cost of the high-voltage direct current transmission system with controllable shut-off capability is reduced, and the reliability of the system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is one of the schematic diagrams of a full-bridge circuit shutting down a grid-commutated converter according to an embodiment of the present invention;

[0061] Figure 2 This is the second schematic diagram of the full-bridge circuit shutting down the grid commutation converter according to the embodiment of the present invention;

[0062] Figure 3 This is the third schematic diagram of the full-bridge circuit shutting down the grid commutation converter according to the embodiment of the present invention;

[0063] Figure 4 It is one of the circuit diagrams of a full-bridge circuit shutting down a grid-commutated converter including a lightning arrester according to an embodiment of the present invention;

[0064] Figure 5The second circuit diagram of the full-bridge circuit including the arrester shutting down the grid commutation converter according to the embodiment of the present invention;

[0065] Figure 6 The third circuit diagram of the full-bridge circuit including the arrester shutting down the grid commutation converter according to the embodiment of the present invention;

[0066] Fig. 7A , Figure 7B , Figure 7C , Fig.7D , Fig. 7E , Figure 7F , Figure 7G , Figure 7H , Fig.7I as well as Figure 7J Schematic diagram of the valve structure of an embodiment of the present invention;

[0067] Fig. 8A is a schematic diagram of a full-bridge submodule according to an embodiment of the present invention;

[0068] Figure 8B This is a schematic diagram of a full-bridge submodule according to an embodiment of the present invention;

[0069] Fig. 9 It is a block diagram of a control method for shutting down a grid commutation converter using a full-bridge circuit according to an embodiment of the present invention;

[0070] Fig.10 It is a schematic flow chart of a control method for shutting down a grid commutation converter using a full-bridge circuit according to an embodiment of the present invention;

[0071] Fig.11 It is a block diagram of a control device for shutting down a grid commutation converter using a full-bridge circuit according to an embodiment of the present invention;

[0072] Fig.12 It is a schematic structural diagram of a single pole of a bipolar direct current transmission system according to an embodiment of the present invention.

[0073] Explanation of the accompanying drawings: 1. upper bridge arm circuit; 2. lower bridge arm circuit; 3. upper bridge transfer circuit; 4. upper bridge shut-off circuit; 5. lower bridge transfer circuit; 6. lower bridge shut-off circuit; 7. upper bridge full-bridge circuit; 8. lower bridge full-bridge circuit; 9. first grid phase-changing converter; 10. second grid phase-changing converter; 11. first converter transformer; 12. second converter transformer; 13. first AC system; 14. DC line; 15. first full-bridge circuit shuts off grid phase-changing converter; 16. second full-bridge circuit shuts off grid phase-changing converter; 17. third converter transformer; 18. fourth converter transformer; 19. second AC system; 201. first control module; 202. second control module; 203. third control module. DETAILED DESCRIPTION

[0074] The following is combined with Figure 1-12 The present invention is described in further detail.

[0075] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will gather the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] An embodiment of the present invention provides a full-bridge circuit shut-off grid-commutating converter, comprising: a main circuit, comprising at least one-phase upper bridge arm circuit and at least one-phase lower bridge arm circuit, one end of the at least one-phase upper bridge arm circuit is connected to the anode bus of the main circuit, the other end of the at least one-phase upper bridge arm circuit is connected to one end of the at least one-phase lower bridge arm circuit, and the other end of the at least one-phase lower bridge arm circuit is connected to the cathode bus of the main circuit.

[0077] At least one phase upper bridge arm circuit and at least one phase lower bridge arm circuit each include a first half-controlled valve and a second half-controlled valve; the first half-controlled valve and the second half-controlled valve are connected in series; one end of the first half-controlled valve of at least one phase upper bridge arm circuit is connected to the anode bus of the main circuit, and one end of the second half-controlled valve of at least one phase upper bridge arm circuit is connected to one end of the second half-controlled valve of at least one phase lower bridge arm circuit; one end of the first half-controlled valve of at least one phase lower bridge arm circuit is connected to the cathode bus of the main circuit; or, at least one phase upper bridge arm circuit and at least one phase lower bridge arm circuit include a first half-controlled valve, one end of the first half-controlled valve of at least one phase upper bridge arm circuit is connected to the anode bus of the main circuit, and the other end of the first half-controlled valve of at least one phase upper bridge arm circuit is connected to one end of the first half-controlled valve of at least one phase lower bridge arm circuit; the other end of the first half-controlled valve of at least one phase lower bridge arm circuit is connected to the cathode bus of the main circuit.

[0078] Reference Figure 1 The main circuit can be a three-phase six-bridge arm circuit, including: three upper bridge arm circuits 1 and three lower bridge arm circuits 2, and there is a one-to-one correspondence between the three upper bridge arm circuits 1 and the three lower bridge arm circuits 2, and each upper bridge arm circuit 1 and lower bridge arm circuit 2 in the corresponding relationship corresponds to one phase of electricity, one end of each upper bridge arm circuit 1 is connected to the anode bus of the main circuit, the other end of each upper bridge arm circuit 1 is connected to one end of the corresponding lower bridge arm circuit 2, and the other end of the corresponding lower bridge arm circuit 2 is connected to the cathode bus of the main circuit.

[0079] Each upper bridge arm circuit 1 and lower bridge arm circuit 2 includes a first half-controlled valve and a second half-controlled valve; wherein the first half-controlled valve and the second half-controlled valve are connected in series; one end of the first half-controlled valve of each upper bridge arm circuit 1 is connected to the anode bus of the main circuit, and one end of the second half-controlled valve of each upper bridge arm circuit 1 is connected to one end of the second half-controlled valve of its corresponding lower bridge arm circuit 2; one end of the first half-controlled valve of each lower bridge arm circuit 2 is connected to the cathode bus of the main circuit.

[0080] In some embodiments, reference Figure 1 The A-phase upper bridge arm circuit 1 includes a first half-controlled valve V42 and a second half-controlled valve V43, which are connected in series, one end of the first half-controlled valve V42 is connected to the main circuit anode bus P1, and one end of the second half-controlled valve V43 is connected to the A-phase lower bridge arm circuit; the B-phase upper bridge arm circuit 1 includes a first half-controlled valve V62 and a second half-controlled valve V63, which are connected in series, one end of the first half-controlled valve V62 is connected to the main circuit anode bus P1, and one end of the second half-controlled valve V63 is connected to the B-phase lower bridge arm circuit 2; the C-phase upper bridge arm circuit 1 includes a first half-controlled valve V22 and a second half-controlled valve V23, which are connected in series, one end of the first half-controlled valve V22 is connected to the main circuit anode bus P1, and one end of the second half-controlled valve V23 is connected to the C-phase lower bridge arm circuit 2.

[0081] The A-phase lower bridge arm circuit 2 includes a first half-controlled valve V12 and a second half-controlled valve V13, which are connected in series, one end of the first half-controlled valve V12 is connected to the cathode bus N1 of the main circuit, and one end of the second half-controlled valve V13 is connected to one end of the second half-controlled valve V43 of the A-phase upper bridge arm circuit 1; the B-phase lower bridge arm circuit 2 includes a first half-controlled valve V32 and a second half-controlled valve V33, which are connected in series, and the first half-controlled valve V32 and the second half-controlled valve V33 are connected in series. One end of the half-controlled valve V32 is connected to the cathode bus N1 of the main circuit, and one end of the second half-controlled valve V33 is connected to one end of the second half-controlled valve V63 of the B-phase upper bridge arm circuit 1; the C-phase lower bridge arm circuit 2 includes a first half-controlled valve V52 and a second half-controlled valve V53, the first half-controlled valve V52 and the second half-controlled valve V53 are connected in series, one end of the first half-controlled valve V52 is connected to the cathode bus N1 of the main circuit, and one end of the second half-controlled valve V53 is connected to the second half-controlled valve V23 of the C-phase upper bridge arm circuit 1.

[0082] The auxiliary circuit includes at least one phase upper bridge transfer circuit, an upper bridge shutdown circuit, an upper bridge full-bridge circuit, at least one phase lower bridge transfer circuit, a lower bridge shutdown circuit and a lower bridge full-bridge circuit; one end of the at least one phase upper bridge transfer circuit is connected to the anode bus of the upper bridge transfer circuit, the other end of the at least one phase upper bridge transfer circuit is connected to the at least one phase upper bridge arm circuit, the upper bridge shutdown circuit is connected in series with the upper bridge full-bridge circuit, and one end of the circuit after the series connection is connected to the anode bus of the upper bridge transfer circuit, and the other end is connected to the anode bus of the main circuit; one end of the at least one phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit, the other end of the at least one phase lower bridge transfer circuit is connected to the at least one phase lower bridge arm circuit, the lower bridge shutdown circuit is connected in series with the lower bridge full-bridge circuit, and one end of the circuit after the series connection is connected to the cathode bus of the lower bridge transfer circuit, and the other end is connected to the cathode bus of the main circuit.

[0083] Reference Figure 1 The auxiliary circuit may include: three upper bridge transfer circuits 3, an upper bridge shutdown circuit 4, an upper bridge full-bridge circuit 7, three lower bridge transfer circuits 5, a lower bridge shutdown circuit 6 and a lower bridge full-bridge circuit 8; wherein the three upper bridge transfer circuits 3 correspond one-to-one to the three upper bridge arm circuits 1, the three lower bridge transfer circuits 5 correspond one-to-one to the three lower bridge arm circuits 2, the upper bridge shutdown circuit 4 corresponds to the three upper bridge arm circuits 1, the lower bridge shutdown circuit 6 corresponds to the three lower bridge arm circuits 2, the upper bridge full-bridge circuit 7 corresponds to the three upper bridge arm circuits 1, and the lower bridge full-bridge circuit 8 corresponds to the three lower bridge arm circuits 2.

[0084] One end of each upper bridge transfer circuit 3 is connected to the upper bridge transfer circuit anode bus, and the other end of each upper bridge transfer circuit 3 is connected to its corresponding upper bridge arm circuit 1. One end of the upper bridge shutdown circuit 4 is connected to one end of the upper bridge full bridge circuit 7, and the other end of the upper bridge shutdown circuit 4 is connected to the upper bridge transfer circuit anode bus.

[0085] One end of each lower bridge transfer circuit 5 is connected to the cathode bus of the lower bridge transfer circuit, and the other end of each lower bridge transfer circuit 5 is connected to its corresponding lower bridge arm circuit 2. One end of the lower bridge shutdown circuit 6 is connected to one end of the lower bridge full bridge circuit 8, and the other end of the lower bridge shutdown circuit 6 is connected to the cathode bus of the lower bridge transfer circuit.

[0086] In some embodiments, the circuit in which the upper bridge shutdown circuit 4 of the auxiliary circuit is connected in series with the upper bridge full-bridge circuit 7 and the anode bus of the main circuit are connected through an isolating switch or a knife switch; the circuit in which the lower bridge shutdown circuit 6 of the auxiliary circuit is connected in series with the lower bridge full-bridge circuit 8 and the cathode bus of the main circuit are connected through an isolating switch or a knife switch.

[0087] In some embodiments, at least one phase upper bridge transfer circuit and at least one phase lower bridge transfer circuit both include: a third half-controlled valve or a first uncontrolled valve; when at least one phase upper bridge arm circuit and at least one phase lower bridge arm circuit include a first half-controlled valve and a second half-controlled valve, one end of the third half-controlled valve or the first uncontrolled valve of at least one phase upper bridge transfer circuit is connected to the anode bus of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of at least one phase upper bridge transfer circuit is connected to the connection point between the first half-controlled valve and the second half-controlled valve of the at least one phase upper bridge arm circuit; one end of the third half-controlled valve or the first uncontrolled valve of at least one phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of at least one phase lower bridge transfer circuit is connected to the connection point between the first half-controlled valve and the second half-controlled valve of the at least one phase lower bridge arm circuit.

[0088] Reference Figure 1 , each upper bridge transfer circuit 3 and each lower bridge transfer circuit 5 include: a third half-controlled valve or a first uncontrolled valve; one end of the third half-controlled valve or the first uncontrolled valve of each upper bridge transfer circuit 3 is connected to the anode bus of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of each upper bridge transfer circuit 3 is connected to the connection point between the first half-controlled valve and the second half-controlled valve of the corresponding upper bridge arm circuit 1; one end of the third half-controlled valve or the first uncontrolled valve of each lower bridge transfer circuit 5 is connected to the cathode bus of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of each lower bridge transfer circuit 5 is connected to the connection point between the first half-controlled valve and the second half-controlled valve of the corresponding lower bridge arm circuit 2, wherein the first half-controlled valve, the second half-controlled valve and the third half-controlled valve all include a half-controlled switch, and the first uncontrolled valve includes an uncontrolled switch; the withstand voltage ratio of the first half-controlled valve and the second half-controlled valve ranges from 0.2 to 5.

[0089] In some embodiments, reference Figure 1 , the A-phase upper bridge transfer circuit 3 includes a third half-controlled valve or a first uncontrolled valve V44, one end of the third half-controlled valve or the first uncontrolled valve V44 is connected to the upper bridge transfer circuit anode bus P2, and the other end of the third half-controlled valve or the first uncontrolled valve V44 is connected to the connection point of the first half-controlled valve V42 and the second half-controlled valve V43 of the A-phase upper bridge arm circuit 1; the B-phase upper bridge transfer circuit 3 includes a third half-controlled valve or the first uncontrolled valve V64, one end of the third half-controlled valve or the first uncontrolled valve V64 is connected to the upper bridge transfer circuit anode bus P 2, the other end of the third half-controlled valve or the first uncontrolled valve V64 is connected to the connection point of the first half-controlled valve V62 and the second half-controlled valve V63 of the B-phase upper bridge arm circuit 1; the C-phase upper bridge transfer circuit 3 includes a third half-controlled valve or the first uncontrolled valve V24, one end of the third half-controlled valve or the first uncontrolled valve V24 is connected to the anode bus P2 of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V24 is connected to the connection point of the first half-controlled valve V22 and the second half-controlled valve V23 of the C-phase upper bridge arm circuit 1.

[0090] The A-phase lower bridge transfer circuit 5 includes a third half-controlled valve or a first uncontrolled valve V14, one end of the third half-controlled valve or the first uncontrolled valve V14 is connected to the cathode bus N2 of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V14 is connected to the connection point of the first half-controlled valve V12 and the second half-controlled valve V13 of the A-phase lower bridge arm circuit 2; the B-phase lower bridge transfer circuit 5 includes a third half-controlled valve or the first uncontrolled valve V34, one end of the third half-controlled valve or the first uncontrolled valve V34 is connected to the cathode bus N2 of the lower bridge transfer circuit 2, the other end of the third half-controlled valve or the first uncontrolled valve V34 is connected to the connection point of the first half-controlled valve V32 and the second half-controlled valve V33 of the B-phase lower bridge arm circuit 2; the C-phase lower bridge transfer circuit 5 includes a third half-controlled valve or the first uncontrolled valve V54, one end of the third half-controlled valve or the first uncontrolled valve V54 is connected to the cathode bus N2 of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V54 is connected to the connection point of the first half-controlled valve V52 and the second half-controlled valve V53 of the C-phase lower bridge arm circuit 5.

[0091] Both the upper bridge shutdown circuit 4 and the lower bridge shutdown circuit 6 include a first full-controlled valve; one end of the first full-controlled valve of the upper bridge shutdown circuit 4 is connected to the upper bridge full-bridge circuit 7, and the other end of the first full-controlled valve of the upper bridge shutdown circuit 4 is connected to the anode bus of the upper bridge transfer circuit; one end of the first full-controlled valve of the lower bridge shutdown circuit 6 is connected to the lower bridge full-bridge circuit 8, and the other end of the first full-controlled valve of the lower bridge shutdown circuit 6 is connected to the cathode bus of the lower bridge transfer circuit; wherein the first full-controlled valve includes at least one of a unidirectional full-controlled switch, a bidirectional full-controlled switch, and a sub-module series switch.

[0092] In some embodiments, reference Figure 1 The upper bridge shutdown circuit 4 includes a first full-controlled valve V71, one end of which is connected to the upper bridge full-bridge circuit 7, and the other end of which is connected to the anode bus P2 of the upper bridge transfer circuit; the lower bridge shutdown circuit 6 includes a first full-controlled valve V72, one end of which is connected to the lower bridge full-bridge circuit 8, and the other end of which is connected to the cathode bus N2 of the lower bridge transfer circuit.

[0093] Both the upper bridge full-bridge circuit 7 and the lower bridge full-bridge circuit 8 include a second fully-controlled valve; one end of the second fully-controlled valve of the upper bridge full-bridge circuit 7 is connected to the anode bus of the main circuit, and the other end of the second fully-controlled valve of the upper bridge full-bridge circuit 7 is connected to one end of the first fully-controlled valve of the upper bridge shutdown circuit 4; one end of the second fully-controlled valve of the lower bridge full-bridge circuit 8 is connected to the cathode bus of the main circuit, and the other end of the second fully-controlled valve of the lower bridge full-bridge circuit 8 is connected to one end of the first fully-controlled valve of the lower bridge shutdown circuit 6.

[0094] In some embodiments, reference Figure 1, one end of the second full-controlled valve V81 of the upper bridge full-bridge circuit 7 is connected to the anode bus P1 of the main circuit, and the other end of the second full-controlled valve V81 of the upper bridge full-bridge circuit 7 is connected to one end of the first full-controlled valve V71 of the upper bridge shutdown circuit 4; one end of the second full-controlled valve V82 of the lower bridge full-bridge circuit 8 is connected to the cathode bus N1 of the main circuit, and the other end of the second full-controlled valve V82 of the lower bridge full-bridge circuit 8 is connected to one end of the first full-controlled valve V72 of the lower bridge shutdown circuit 6.

[0095] In some embodiments, the positions of the upper bridge shutdown circuit and the upper bridge full-bridge circuit can be interchanged; the positions of the lower bridge shutdown circuit and the lower bridge full-bridge circuit can be interchanged.

[0096] In some embodiments, the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit only include a first half-controlled valve but do not include a second half-controlled valve, one end of the first half-controlled valve of the at least one-phase upper bridge arm circuit is connected to the anode bus of the main circuit, and the other end of the first half-controlled valve of the at least one-phase upper bridge arm circuit is connected to one end of the first half-controlled valve of the at least one-phase lower bridge arm circuit; the other end of the first half-controlled valve of the at least one-phase lower bridge arm circuit is connected to the cathode bus of the main circuit.

[0097] Reference Figure 2 In the case where each upper bridge arm circuit 1 and each lower bridge arm circuit 2 include a first half-controlled valve but do not include a second half-controlled valve, one end of the first half-controlled valve of each upper bridge arm circuit 1 is connected to the anode bus of the main circuit, and the other end of the first half-controlled valve of each upper bridge arm circuit 1 is connected to one end of the first half-controlled valve of its corresponding lower bridge arm circuit 2; the other end of the first half-controlled valve of each lower bridge arm circuit 2 is connected to the cathode bus of the main circuit.

[0098] In some embodiments, when at least one phase upper bridge arm circuit and at least one phase lower bridge arm circuit include a first half-controlled valve but do not include a second half-controlled valve, one end of the third half-controlled valve or the first uncontrolled valve of the at least one phase upper bridge transfer circuit is connected to the anode bus of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one phase upper bridge transfer circuit is connected to one end of the first half-controlled valve of the at least one phase upper bridge arm circuit; one end of the third half-controlled valve or the first uncontrolled valve of the at least one phase lower bridge transfer circuit is connected to one end of the first half-controlled valve of the at least one phase lower bridge arm circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit.

[0099] Reference Figure 2, one end of the third half-controlled valve or the first uncontrolled valve V44 of the upper bridge transfer circuit of phase A is connected to the anode bus P2 of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V44 of the upper bridge transfer circuit of phase A is connected to one end of the first half-controlled valve V41 of the upper bridge arm circuit 1 of phase A; one end of the third half-controlled valve or the first uncontrolled valve V14 of the lower bridge transfer circuit of phase A is connected to the cathode bus N2 of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V14 of the lower bridge transfer circuit of phase A is connected to one end of the first half-controlled valve V11 of the lower bridge arm circuit 2 of phase A;

[0100] One end of the third half-controlled valve or the first uncontrolled valve V64 of the upper bridge transfer circuit of phase B is connected to the anode bus P2 of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V64 of the upper bridge transfer circuit of phase B is connected to one end of the first half-controlled valve V61 of the upper bridge arm circuit 1 of phase B; one end of the third half-controlled valve or the first uncontrolled valve V34 of the lower bridge transfer circuit of phase B is connected to the cathode bus N2 of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V34 of the lower bridge transfer circuit of phase B is connected to one end of the first half-controlled valve V31 of the lower bridge arm circuit 2 of phase B;

[0101] One end of the third half-controlled valve or the first uncontrolled valve V24 of the C-phase upper bridge transfer circuit is connected to the anode bus P2 of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V24 of the C-phase upper bridge transfer circuit is connected to one end of the first half-controlled valve V21 of the C-phase upper bridge arm circuit 1; one end of the third half-controlled valve or the first uncontrolled valve V54 of the C-phase lower bridge transfer circuit is connected to the cathode bus N2 of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve V54 of the C-phase lower bridge transfer circuit is connected to one end of the first half-controlled valve V51 of the C-phase lower bridge arm circuit 2.

[0102] In some embodiments, the first half-controlled valve, and / or the second half-controlled valve, and / or the third half-controlled valve or the first uncontrolled valve further comprises a reactor. Optionally, the first fully-controlled valve further comprises a reactor.

[0103] In some embodiments, the upper bridge shutdown circuit and the lower bridge shutdown circuit also include a fourth half-controlled valve, which is connected in series with the first full-controlled valve; the cathode of the fourth half-controlled valve is connected to the positive pole of the first full-controlled valve or the anode of the fourth half-controlled valve is connected to the negative pole of the first full-controlled valve.

[0104] Reference Figure 3 The upper bridge shutdown circuit 4 also includes a fourth half-controlled valve V73, which is connected in series with the first full-controlled valve V71, and the anode of the fourth half-controlled valve V73 is connected to the cathode of the first full-controlled valve V71; the lower bridge shutdown circuit 6 also includes a fourth half-controlled valve V74, which is connected in series with the first full-controlled valve V72, and the cathode of the fourth half-controlled valve V74 is connected to the positive electrode of the first full-controlled valve V72.

[0105] Reference Figure 4Each first fully controlled valve's one-way fully controlled switch uses at least one IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor) in series, the half-controlled switches of each first half-controlled valve and each second half-controlled valve are composed of at least one thyristor in series, the uncontrolled switch of each first uncontrolled valve is composed of at least one diode in series, and each second fully-controlled valve is composed of full-bridge sub-modules in series; for example, the unidirectional fully-controlled switches of the first fully-controlled valve V71 of the A-phase upper bridge shutdown circuit and the first fully-controlled valve V72 of the A-phase lower bridge shutdown circuit are composed of multiple IGBT modules in series; the half-controlled switches of the first half-controlled valve V42 and the second half-controlled valve V43 of the A-phase upper bridge arm circuit and the first half-controlled valve V12 and the second half-controlled valve V13 of the A-phase lower bridge arm circuit are composed of multiple thyristors in series; the uncontrolled switches of the first uncontrolled valve V44 of the A-phase upper bridge transfer circuit and the first uncontrolled valve V14 of the A-phase lower bridge transfer circuit are composed of multiple diodes in series, and the second fully-controlled valve V81 of the A-phase upper bridge full-bridge circuit and the second fully-controlled valve V82 of the A-phase lower bridge full-bridge circuit are composed of full-bridge sub-modules in series.

[0106] In addition, phases B and C share the first fully-controlled valve with phase A; the one-way half-controlled switches of the first half-controlled valve and the second half-controlled valve corresponding to phases B and C are the same as the one-way half-controlled switches of the first half-controlled valve and the second half-controlled valve corresponding to A; the uncontrolled switches of the first uncontrolled valves corresponding to phases B and C are the same as the uncontrolled switches of the first uncontrolled valves corresponding to A; phases B and C share the second fully-controlled valve with phase A.

[0107] In some embodiments, reference Figure 4 Each first fully-controlled valve, each first half-controlled valve, each second half-controlled valve, each first uncontrolled valve and each second fully-controlled valve is connected in parallel with a lightning arrester to protect each first fully-controlled valve, each first half-controlled valve, each second half-controlled valve, each first uncontrolled valve and each second fully-controlled valve from normal use. For example, the first half-controlled valve V42 of the upper bridge arm circuit of phase A is connected in parallel with the second lightning arrester F42, and the second half-controlled valve V43 is connected in parallel with the third lightning arrester F43; the first half-controlled valve V12 of the lower bridge arm circuit of phase A is connected in parallel with the second lightning arrester F12, and the second half-controlled valve V13 is connected in parallel with the third lightning arrester F13; the first half-controlled valve V62 of the upper bridge arm circuit of phase B is connected in parallel with the second lightning arrester F62, and the second half-controlled valve V63 is connected in parallel with the third lightning arrester F63; the first half-controlled valve V32 of the lower bridge arm circuit of phase B is connected in parallel with the second lightning arrester F32, and the second half-controlled valve V33 is connected in parallel with the third lightning arrester F33; the first half-controlled valve V22 of the upper bridge arm circuit of phase C is connected in parallel with the second lightning arrester F22, and the second half-controlled valve V23 is connected in parallel with the third lightning arrester F23; the first half-controlled valve V52 of the lower bridge arm circuit of phase C is connected in parallel with the second lightning arrester F52, and the second half-controlled valve V53 is connected in parallel with the third lightning arrester F53.

[0108] The first uncontrolled valve V44 of the A phase upper bridge transfer circuit is connected in parallel with the fourth lightning arrester F44, and the first uncontrolled valve V14 of the A phase lower bridge transfer circuit is connected in parallel with the fourth lightning arrester F14; the first uncontrolled valve V64 of the B phase upper bridge transfer circuit is connected in parallel with the fourth lightning arrester F64, and the first uncontrolled valve V34 of the B phase lower bridge transfer circuit is connected in parallel with the fourth lightning arrester F34; the first uncontrolled valve V24 of the C phase upper bridge transfer circuit is connected in parallel with the fourth lightning arrester F24, and the first uncontrolled valve V54 of the C phase lower bridge transfer circuit is connected in parallel with the fourth lightning arrester F54; the first fully-controlled valve V71 of the upper bridge shut-off circuit is connected in parallel with the fifth lightning arrester F71, and the first fully-controlled valve V72 of the lower bridge shut-off circuit is connected in parallel with the fifth lightning arrester F72.

[0109] The second fully-controlled valve V81 of the upper full-bridge circuit is connected in parallel with the sixth lightning arrester F81, and the second fully-controlled valve V82 of the lower full-bridge circuit is connected in parallel with the sixth lightning arrester F82.

[0110] refer to Figure 5 Each upper bridge arm circuit and each lower bridge arm circuit includes a first half-controlled valve but does not include a second half-controlled valve, and the half-controlled switch of each first half-controlled valve is composed of at least one thyristor connected in series.

[0111] In some embodiments, reference Figure 5 Each first half-controlled valve is connected in parallel with a lightning arrester to protect the normal use of each first half-controlled valve, for example, the first half-controlled valve V41 of the upper bridge arm circuit of phase A is connected in parallel with the first lightning arrester F41, and the first half-controlled valve V11 of the lower bridge arm circuit of phase A is connected in parallel with the first lightning arrester F11; the first half-controlled valve V61 of the upper bridge arm circuit 1 of phase B is connected in parallel with the first lightning arrester F61, and the first half-controlled valve V31 of the lower bridge arm circuit of phase B is connected in parallel with the first lightning arrester F31; the first half-controlled valve V21 of the upper bridge arm circuit of phase C is connected in parallel with the first lightning arrester F21, and the first half-controlled valve V51 of the lower bridge arm circuit of phase C is connected in parallel with the first lightning arrester F51.

[0112] refer to Figure 6 The upper bridge shutdown circuit also includes a fourth half-controlled valve V73, which is connected in series with the first full-controlled valve V71, and the anode of the fourth half-controlled valve V73 is connected to the cathode of the first full-controlled valve V71; the lower bridge shutdown circuit also includes a fourth half-controlled valve V74, which is connected in series with the first full-controlled valve V72, and the cathode of the fourth half-controlled valve V74 is connected to the anode of the first full-controlled valve V72; the half-controlled switch of each fourth half-controlled valve is composed of at least one thyristor connected in series.

[0113] In some embodiments, reference Figure 6 Each fourth half-controlled valve is connected in parallel with a lightning arrester to protect the normal use of each fourth half-controlled valve. For example, the fourth half-controlled valve V73 is connected in parallel with the seventh lightning arrester F73, and the fourth half-controlled valve V74 is connected in parallel with the seventh lightning arrester F74.

[0114] In some embodiments, the fully-controlled switch includes at least one fully-controlled device connected in series, and the fully-controlled device includes at least one of IGCT (Integrated Gate Commutated Thyristors), IGBT, reverse-blocking IGCT, GTO (Gate Turn-Off Thyristor), and MOSFET (Metal Oxide Semiconductor Field Effect Transistor); the half-controlled switch includes at least one half-controlled device connected in series, and the half-controlled device includes a thyristor; the uncontrolled switch includes at least one uncontrolled device connected in series, and the uncontrolled device includes a diode.

[0115] Reference Fig. 7A The uncontrolled switch includes at least one diode D1 connected in series, which cannot be controlled to be turned on and off, and has a unidirectional current-carrying capacity and a unidirectional blocking voltage capacity; Figure 7B The half-controlled switch includes a thyristor T1 connected in series, which can only control the on-state but not the off-state, and has a unidirectional current-carrying capacity and a bidirectional blocking voltage capacity. Optionally, the half-controlled switch is composed of a thyristor and a diode connected in series or in parallel; refer to Figure 7C The unidirectional fully controlled switch includes an IGBT module connected in series, the IGBT module includes an IGBT (T2) and a diode D2 connected in anti-parallel thereto, which is only unidirectionally controlled to be turned on and off, and has bidirectional current flow and unidirectional blocking voltage capabilities; refer to Fig.7D The unidirectional fully controlled switch includes a series-connected IGCT (T3), which is only unidirectionally controlled to be turned on and off, and has a unidirectional current-carrying and unidirectional blocking voltage capability. If it is a series-connected reverse-resistance IGCT, it has a unidirectional current-carrying and bidirectional blocking voltage capability; refer to Fig. 7E The unidirectional fully controlled switch includes an IGBT module and a diode D1 connected in series, which can only be turned on and off in one direction, and has the capability of unidirectional current flow and bidirectional voltage blocking; Figure 7F The unidirectional fully controlled switch includes a reverse-resistance IGCT (T3) and a thyristor T1 connected in anti-parallel and then in series. It has a bidirectional control opening and a unidirectional control closing, and has a bidirectional current passing and bidirectional blocking voltage capability; refer to Figure 7G The bidirectional fully controlled switch includes a forward IGBT module and a reverse IGBT module connected in series, which can be bidirectionally controlled to be turned on and off, and has a bidirectional current-carrying capacity and a bidirectional blocking voltage capacity; refer to Figure 7H The bidirectional fully controlled switch includes a series circuit of reverse-resistance type IGCT (T3) connected in anti-parallel, which can be bidirectionally controlled to be turned on and off, and has bidirectional current-carrying capacity and bidirectional blocking voltage capacity; refer to Fig.7IThe sub-module series switch includes a half-bridge sub-module connected in series, the half-bridge sub-module includes two IGBT modules M1, M2 and a capacitor C1, the connection point of the two IGBT modules M1, M2 is used as the positive electrode of the sub-module, wherein the other end of the IGBT module M2 is used as the negative electrode of the sub-module, and the half-bridge sub-modules are connected in series, which only controls opening and closing in one direction, and has a bidirectional current-carrying capacity and a unidirectional blocking voltage capacity; refer to Figure 7J The sub-module series switch includes a full-bridge sub-module connected in series. The full-bridge sub-module includes four IGBT modules M3, M4, M5, M6 and a capacitor C1. The IGBT modules M3 and M4 are connected in series and then connected in parallel with M5 and M6, and are also connected in parallel with the capacitor C1. The connection point of the IGBT modules M3 and M4 connected in series serves as the positive electrode of the sub-module, and the connection point of the IGBT modules M5 and M6 connected in series serves as the negative electrode of the sub-module. The full-bridge sub-modules are connected in series, can be bidirectionally controlled to be turned on and off, and have bidirectional current-carrying capacity and bidirectional blocking voltage capacity.

[0116] 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 the reverse resistance type IGCT is configured with a corresponding drive circuit and a buffer circuit; the buffer circuit is composed of at least a capacitor, or a resistor and a capacitor series circuit.

[0117] In some embodiments, the second fully controlled valve includes at least one of a full-bridge submodule connected in series, a quasi-full-bridge submodule, a midpoint clamped submodule, a double half-bridge series submodule, a double full-bridge series submodule, a clamped twin submodule, a cross-connected twin submodule, a self-resistance submodule, or a diode clamped submodule. Fig. 8A The full-bridge submodule includes four IGBT modules M7, M8, M9, M10 and a capacitor C2, and the IGBT module includes an IGBT and a diode; the IGBT modules M7 and M8 are connected in series and then connected in parallel with M9 and M10, and are also connected in parallel with the capacitor C2, the connection point of the IGBT modules M7 and M8 connected in series serves as the positive electrode of the submodule, and the connection point of the IGBT modules M9 and M10 connected in series serves as the negative electrode of the submodule; when current flows in the IGBT modules M8 and M9, the full-bridge submodule presents a negative pressure.

[0118] In some embodiments, reference Figure 8BThe quasi-full-bridge submodule includes two IGBT modules M11 and M12, two diodes D3 and D4 and a capacitor C2, and the IGBT module includes an IGBT and a diode; the diode D3 and the IGBT module M11 are connected in series, and the diode D4 and the IGBT module M12 are connected in series and then connected in parallel, and are also connected in parallel with the capacitor C2, the connection point where the diode D3 and the IGBT module M11 are connected in series serves as the positive electrode of the quasi-full-bridge submodule, and the connection point where the diode D4 and the IGBT module M12 are connected in series serves as the negative electrode of the quasi-full-bridge submodule; when current flows in the IGBT modules M11 and M12, the quasi-full-bridge submodule presents a negative pressure.

[0119] In some embodiments, Fig. 8A and Figure 8B The IGBT modules in the can be replaced by IGCT modules.

[0120] The present invention provides a full-bridge circuit shut-off grid commutation converter control method, which is executed by an electronic device, wherein 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, or a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud computing services. The terminal device can be a smart phone, a tablet computer, a laptop 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 via wired or wireless communication, and the embodiments of the present invention do not impose specific restrictions.

[0121] Reference Fig. 9 A full-bridge circuit shut-down grid commutation converter control method includes: step S101, step S102 and step S103, wherein:

[0122] S101. When operating parameter information of a full-bridge circuit shutting down a grid-commutating converter is obtained, inverter state control information is generated based on the parameter information, and a main circuit is controlled to operate in an inverter state based on the inverter state control information.

[0123] In some embodiments, the electronic device monitors the operating state of the full-bridge circuit shutting down the grid-switching converter in real time, and obtains the operating parameter information of the operating state of the full-bridge circuit shutting down the grid-switching converter, such as AC voltage, DC current, etc. When the electronic device obtains the operating state of the full-bridge circuit shutting down the grid-switching converter, the electronic device generates inverter state control information, such as a trigger pulse, and the full-bridge circuit shutting down the grid-switching converter operates in the inverter state based on the inverter state control information; for example, the electronic device controls the A-phase upper bridge arm circuit 1, the first half-controlled valve V42 and the second half-controlled valve V43 of the A-phase lower bridge arm circuit 2, the first half-controlled valve V12 and the second half-controlled valve V13 of the A-phase lower bridge arm circuit 2, the first half-controlled valve V62 and the second half-controlled valve V63 of the B-phase upper bridge arm circuit 1, the first half-controlled valve V32 and the second half-controlled valve V33 of the B-phase lower bridge arm circuit 2, the first half-controlled valve V22 and the second half-controlled valve V23 of the C-phase upper bridge arm circuit 1, and the first half-controlled valve V52 and the second half-controlled valve V53 of the C-phase lower bridge arm circuit 2 operate in the inverter state according to the six-pulse inverter working mode.

[0124] S102. When it is obtained that the turn-off angle reference value is less than the minimum turn-off angle setting or the phase-changing fault information is obtained, a circuit conduction instruction and negative voltage control information are generated during the phase-changing period, and the transfer circuit and the turn-off circuit in the auxiliary circuit corresponding to the phase-changing bridge arm are controlled to be turned on based on the circuit conduction instruction, and the full-bridge circuit of the auxiliary circuit corresponding to the phase-changing bridge arm is controlled to present negative pressure based on the negative voltage control information.

[0125] In some embodiments, 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 constant. When the turn-off angle reference value is obtained to be less than the minimum turn-off angle constant, the electronic device generates a circuit conduction instruction and negative pressure control information during the commutation period. Subsequently, the electronic device controls the third half-controlled valve or the first uncontrolled valve of the transfer circuit and the first fully-controlled valve of the shutdown circuit in the auxiliary circuit corresponding to the commutation bridge arm to be turned on based on the circuit conduction instruction, and at the same time controls the second fully-controlled valve of the full-bridge circuit of the auxiliary circuit corresponding to the commutation bridge arm to present a negative pressure based on the negative pressure control information, so that the current of the commutation bridge arm is transferred to the transfer circuit and the shutdown circuit and the full-bridge circuit of the auxiliary circuit. For example, when the A-phase upper bridge arm circuit 1 commutates to the B-phase upper bridge arm circuit 1, at this time, if the turn-off angle reference value is less than the minimum turn-off angle constant (such as 3°), the electronic device controls the A-phase of the auxiliary circuit based on the circuit conduction instruction. The third half-controlled valve or the first uncontrolled valve V44 of the upper bridge transfer circuit 1 and the first fully-controlled valve V71 of the upper bridge shut-off circuit 4 are turned on, and the second fully-controlled valve V81 of the upper bridge full-bridge circuit 7 is controlled to present a negative pressure based on the negative pressure control information, so that the current of the A-phase upper bridge arm circuit 1 is transferred to the A-phase upper bridge transfer circuit 3, the upper bridge shut-off circuit 4 and the upper bridge full-bridge circuit 7 of the auxiliary circuit; when the A-phase lower bridge arm circuit 2 switches to the B-phase lower bridge arm circuit 2, at this time, when the shutdown angle reference value is obtained to be less than In the case of the minimum shut-off angle setting (such as 3°), the electronic device controls the third half-controlled valve or the first uncontrolled valve V14 of the A-phase lower bridge transfer circuit 5 of the auxiliary circuit and the first fully-controlled valve V72 of the lower bridge shut-off circuit 6 based on the circuit conduction instruction, and controls the second fully-controlled valve V82 of the lower bridge full-bridge circuit 8 to present a negative pressure based on the negative pressure control information, so that the current of the A-phase lower bridge arm circuit 2 is transferred to the A-phase lower bridge transfer circuit 5, the lower bridge shut-off circuit 6 and the lower bridge full-bridge circuit 8 of the auxiliary circuit. In the case of obtaining the commutation fault information, the control method is the same as above. The above-mentioned minimum shut-off angle setting ranges from -30° to 10°.

[0126] In some embodiments, the commutation fault information includes fault information that causes the natural commutation failure of the commutation bridge arm of the main circuit or the auxiliary commutation failure of the full-bridge circuit. The above-mentioned commutation fault information includes the AC system fault or DC system fault that shuts down the connection of the grid commutation converter of the full-bridge circuit. The AC system fault can be judged based on the increase of the zero-sequence component of the AC voltage, the sudden change of the AC voltage, the drop of the AC voltage amplitude, the increase of the AC voltage harmonics, and the increase of the DC current. The DC system fault can be judged based on the drop of the DC voltage and the increase of the DC current, but it is not limited to this. The above-mentioned commutation fault information also includes the determination based on the closing time of the first half-controlled valve of the commutation bridge arm, the AC current and the AC voltage on the grid side or the valve side. If the first half-controlled valve of the commutation bridge arm has not been closed when it starts to bear the positive pressure under the normal AC voltage, it is judged that the commutation fault information occurs, but it is not limited to this.

[0127] S103, when the first half-controlled valve of the commutation bridge arm of the main circuit is restored to be closed, generating a circuit closing instruction to control the full-bridge circuit and / or the shut-off circuit corresponding to the commutation bridge arm to be closed.

[0128] In some embodiments, when the electronic device detects that the first half-controlled valve of the commutation bridge arm of the main circuit is restored to be closed, a circuit shutdown instruction is generated, and the full-bridge circuit shuts down the grid commutation converter in response to the circuit shutdown instruction, and controls the full-bridge circuit and / or the shutdown circuit corresponding to the commutation bridge arm to be shut down, so that the current is transferred from the phase electricity where the commutation bridge arm is located to the phase electricity to be commutated, effectively suppressing the occurrence of commutation failure, reducing the shutdown angle reference value, and thus reducing the reactive power consumption; for example, when the electronic device detects that the first half-controlled valve V42 of the A-phase upper bridge arm circuit 1 of the main circuit is restored to be closed, a circuit shutdown instruction is generated, and the full-bridge circuit shuts down the grid commutation converter in response to the circuit shutdown instruction, and controls the upper bridge full-bridge circuit 7 and / or the upper bridge shutdown circuit 4 corresponding to the A-phase upper bridge arm circuit 1 to be shut down, so that the current is transferred from the A-phase electricity where the A-phase upper bridge arm circuit 1 is located to the B-phase electricity; wherein, the upper bridge full-bridge circuit 7 is controlled to present a negative pressure, for Fig. 8A The full-bridge submodule controls Fig. 8A The IGBT modules M8 and M9 of the full-bridge submodule are turned on to achieve Figure 8B The full-bridge submodule controls Figure 8B The IGBT modules M11 and M12 of the quasi-full-bridge sub-module are turned on; when the A-phase upper bridge transfer circuit is the first uncontrolled valve V44, it can be turned on without applying a trigger pulse.

[0129] In some embodiments, reference Fig.10 When the main circuit is in inverter operation, determine whether the commutation bridge arm has failed in natural commutation according to the shutdown angle reference value or the commutation fault information. When there is no natural commutation failure of the commutation bridge arm, continue to control the main circuit to be in inverter operation; when there is a possible commutation failure of the commutation bridge arm, control the negative voltage of the full-bridge circuit and control the corresponding transfer circuit and shutdown circuit of the auxiliary circuit to be turned on. Subsequently, when the commutation bridge arm resumes shutdown, control the full-bridge circuit and / or shutdown circuit of the auxiliary circuit to be turned off.

[0130] In some embodiments, when the full-bridge circuit shuts down the grid-commutating converter for inverter operation, the shutdown angle reference value is set to be less than the minimum shutdown angle setting; when the shutdown angle reference value is obtained to be less than the minimum shutdown angle setting and the first half-controlled valve of the commutating bridge arm of the main circuit resumes shutdown, a circuit shutdown instruction is generated, and based on the circuit shutdown instruction, only the full-bridge circuit corresponding to the commutating bridge arm is controlled to be shut down.

[0131] In some embodiments, when the full-bridge circuit shuts down the grid-commutating converter for inverter operation, the capacitor voltage of the sub-module of the full-bridge circuit of the auxiliary circuit is lower than the rated value and exceeds the first threshold, and the first half-controlled valve of the commutation bridge arm of the main circuit resumes shutdown, the circuit shutdown instruction is generated in advance; and / or the number of sub-modules of the full-bridge circuit is increased; and / or the circuit conduction instruction for controlling the conduction of the corresponding transfer circuit and the shutdown circuit and the negative pressure control information for controlling the sub-module of the full-bridge circuit to present a negative pressure are generated in advance; the value range of the above-mentioned first threshold is 0.01 to 0.6 times the rated capacitor voltage.

[0132] In some embodiments, when the sub-module capacitor voltage is greater than or equal to the rated value and exceeds the second threshold, and when the first half-controlled valve of the commutation bridge arm of the main circuit resumes shutdown, the generation of the circuit shutdown instruction is delayed; and / or the number of sub-modules of the full-bridge circuit is reduced; and / or the generation of the circuit conduction instruction for controlling the conduction of the corresponding transfer circuit and the shutdown circuit and the negative pressure control information for controlling the sub-module of the full-bridge circuit to present a negative pressure is delayed; the above-mentioned second threshold value ranges from 0.01 to 0.6 times the rated capacitor voltage.

[0133] In some embodiments, the recovery and shutdown of the first half-controlled valve included in the phase-changing bridge arm of the main circuit is determined by judging the reverse recovery time of the first half-controlled valve, and the reverse recovery time is greater than or equal to the reverse recovery time of the thyristor included in the first half-controlled valve, wherein the reverse recovery time of the thyristor is typically 200 to 800 us, and the reverse recovery time of the second half-controlled valve is typically 200 us to 1.5 ms.

[0134] In some embodiments, the circuit after the upper bridge shutdown circuit of the auxiliary circuit is connected in series with the upper bridge full-bridge circuit and the anode bus of the main circuit are connected through an isolating switch and / or a knife switch, and the circuit after the lower bridge shutdown circuit of the auxiliary circuit is connected in series with the lower bridge full-bridge circuit and the cathode bus of the main circuit are connected through an isolating switch and / or a knife switch, and a switch separation instruction is generated when the auxiliary circuit fault information is obtained, and the isolating switch and / or the knife switch are controlled to separate based on the switch separation instruction.

[0135] In some embodiments, the auxiliary circuit fault information includes auxiliary circuit device or sub-module failure affecting operation, but is not limited thereto.

[0136] In some embodiments, when the full-bridge circuit shuts down the grid-commutated converter rectification operation, the full-bridge circuit can also be used to provide auxiliary commutation voltage to reduce the trigger angle reference value, thereby reducing reactive power consumption and improving the power factor.

[0137] Reference Fig.11The full-bridge circuit shut-down grid commutation converter control device 20 may specifically include: a first control module 201, a second control module 202 and a third control module 203, wherein:

[0138] The first control module 201 is used to generate inverter state control information based on the parameter information when the operation parameter information of the full-bridge circuit shutting down the grid-commutated converter is obtained, and control the main circuit to operate in the inverter state based on the inverter state control information;

[0139] The second control module 202 is used to generate a circuit conduction instruction and negative voltage control information during the commutation period when the turn-off angle reference value is less than the minimum turn-off angle setting value or the commutation fault information is obtained, and control the transfer circuit and the turn-off circuit in the auxiliary circuit corresponding to the commutation bridge arm to be turned on based on the circuit conduction instruction, and control the full-bridge circuit of the auxiliary circuit corresponding to the commutation arm to present a negative voltage based on the negative voltage control information;

[0140] The third control module 203 is used to generate a circuit shutdown instruction to control the full-bridge circuit and / or shutdown circuit corresponding to the commutation bridge arm to shut down when the first half-controlled valve of the commutation bridge arm of the main circuit resumes shutdown.

[0141] In some embodiments, the first control module 201 may include a logic circuit, or may be implemented by a central processing unit, a microprocessor, a digital signal processor, or a field programmable gate array included in the device;

[0142] The second control module 202 may include a logic circuit, or may be implemented by a central processing unit, a microprocessor, a digital signal processor, or a field programmable gate array included in the device;

[0143] The third control module 203 may include a logic circuit, or may be implemented by a central processing unit, a microprocessor, a digital signal processor, or a field programmable gate array included in the device.

[0144] An embodiment of the present invention provides a high voltage direct current transmission system, comprising a full bridge circuit shut-off grid commutation converter.

[0145] 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, and the two-terminal direct current transmission system or the multi-terminal direct current transmission system respectively includes a monopolar direct current transmission system, a bipolar direct current transmission system or a back-to-back direct current system.

[0146] The two-terminal DC power transmission system or the multi-terminal DC power transmission system requires that some or all of the converters in the inverter operation adopt the full-bridge circuit to shut down the grid commutation converter.

[0147] Reference Fig.12 , Fig.12The structure of a single pole of a bipolar direct current transmission system is shown, and a single pole includes a first alternating current system 13, a first grid-commutated converter 9, a second grid-commutated converter 10, a first converter transformer 11, a second converter transformer 12, a direct current line 14, a second alternating current system 19, a first full-bridge circuit-off grid-commutated converter 15, a second full-bridge circuit-off grid-commutated converter 16, a third converter transformer 17, and a fourth converter transformer 18. When the power is positively transmitted, the alternating current of the first alternating current system 13 passes through the first converter transformer 11 and the second converter transformer 12, and is rectified into direct current by the first grid-commutated converter 9 and the second grid-commutated converter 10, and is transmitted to the first full-bridge circuit-off grid-commutated converter 15 and the second full-bridge circuit-off grid-commutated converter 16 through the direct current line 14, and is inverted into alternating current, and is transmitted to the second alternating current system 19 after passing through the third converter transformer 17 and the fourth converter transformer 18, thereby realizing the transmission of direct current power. The first full-bridge circuit shuts down the grid-commutated converter 15 and the second full-bridge circuit shuts down the grid-commutated converter 16, which have the capability of suppressing commutation failure and ensure the reliability of direct current power transmission.

[0148] The above are only some embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A full-bridge circuit shuts down a grid-commutated converter, characterized in that: include: A main circuit, comprising at least one-phase upper bridge arm circuit and at least one-phase lower bridge arm circuit, wherein one end of the at least one-phase upper bridge arm circuit is connected to the anode bus of the main circuit, the other end of the at least one-phase upper bridge arm circuit is connected to one end of the at least one-phase lower bridge arm circuit, and the other end of the at least one-phase lower bridge arm circuit is connected to the cathode bus of the main circuit; an auxiliary circuit, comprising at least one phase upper bridge transfer circuit, an upper bridge shutdown circuit, an upper bridge full-bridge circuit, at least one phase lower bridge transfer circuit, a lower bridge shutdown circuit, and a lower bridge full-bridge circuit; One end of the at least one-phase upper bridge transfer circuit is connected to the upper bridge transfer circuit anode bus, the other end of the at least one-phase upper bridge transfer circuit is connected to the at least one-phase upper bridge arm circuit, the upper bridge shutdown circuit is connected in series with the upper bridge full-bridge circuit, and one end of the series-connected circuit is connected to the upper bridge transfer circuit anode bus, and the other end is connected to the main circuit anode bus; One end of the at least one-phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end of the at least one-phase lower bridge transfer circuit is connected to the at least one-phase lower bridge arm circuit. The lower bridge shutdown circuit is connected in series with the lower bridge full-bridge circuit, and one end of the series-connected circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end is connected to the cathode bus of the main circuit.

2. The full-bridge circuit shut-down grid-commutated converter according to claim 1, characterized in that: The at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include: a first half-controlled valve and / or a second half-controlled valve; In the case where both the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve and a second half-controlled valve, the first half-controlled valve and the second half-controlled valve are connected in series; one end of the first half-controlled valve of the at least one-phase upper bridge arm circuit is connected to the anode bus of the main circuit, and one end of the second half-controlled valve of the at least one-phase upper bridge arm circuit is connected to one end of the second half-controlled valve of the at least one-phase lower bridge arm circuit; one end of the first half-controlled valve of the at least one-phase lower bridge arm circuit is connected to the cathode bus of the main circuit; or, In the case where the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve, one end of the first half-controlled valve of the at least one-phase upper bridge arm circuit is connected to the anode bus of the main circuit, and the other end of the first half-controlled valve of the at least one-phase upper bridge arm circuit is connected to one end of the first half-controlled valve of the at least one-phase lower bridge arm circuit; the other end of the first half-controlled valve of the at least one-phase lower bridge arm circuit is connected to the cathode bus of the main circuit.

3. The full-bridge circuit shut-down grid-commutated converter according to claim 1, characterized in that: The at least one-phase upper bridge transfer circuit and the at least one-phase lower bridge transfer circuit both include: a third half-controlled valve or a first uncontrolled valve; In the case where the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve and a second half-controlled valve, one end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase upper bridge transfer circuit is connected to the anode bus of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase upper bridge transfer circuit is connected to the connection point between the first half-controlled valve and the second half-controlled valve of the at least one-phase upper bridge arm circuit; one end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase lower bridge transfer circuit is connected to the connection point between the first half-controlled valve and the second half-controlled valve of the at least one-phase lower bridge arm circuit; or, In the case where the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve, one end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase upper bridge transfer circuit is connected to the anode bus of the upper bridge transfer circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase upper bridge transfer circuit is connected to one end of the first half-controlled valve of the at least one-phase upper bridge arm circuit; one end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase lower bridge transfer circuit is connected to one end of the first half-controlled valve of the at least one-phase lower bridge arm circuit, and the other end of the third half-controlled valve or the first uncontrolled valve of the at least one-phase lower bridge transfer circuit is connected to the cathode bus of the lower bridge transfer circuit.

4. The full-bridge circuit shut-down grid-commutated converter according to claim 3, characterized in that: The first half-controlled valve, the second half-controlled valve and the third half-controlled valve all include a half-controlled switch; the first uncontrolled valve includes an uncontrolled switch; The half-controlled switch is composed of semiconductor devices that can be controlled to be turned on but not controlled to be turned off in series, and the semiconductor devices that can be controlled to be turned on but not controlled to be turned off include but are not limited to thyristors; The uncontrolled switch is composed of semiconductor devices that are uncontrolled to be turned on and off in series, and the semiconductor devices that are uncontrolled to be turned on and off include but are not limited to diodes.

5. The full-bridge circuit shut-down grid-commutated converter according to claim 3, characterized in that: The first half-controlled valve, and / or the second half-controlled valve, and / or the third half-controlled valve or the first uncontrolled valve is connected in parallel with a lightning arrester.

6. The full-bridge circuit shut-down grid-commutated converter according to claim 2, characterized in that: In the case where the at least one-phase upper bridge arm circuit and the at least one-phase lower bridge arm circuit include a first half-controlled valve and a second half-controlled valve, a withstand voltage ratio of the first half-controlled valve and the second half-controlled valve ranges from 0.2 to 5.

7. The full-bridge circuit shut-down grid-commutated converter according to claim 3, characterized in that: The first half-controlled valve, and / or the second half-controlled valve, and / or the third half-controlled valve or the first uncontrolled valve further includes a reactor.

8. The full-bridge circuit shut-down grid-commutated converter according to claim 1, characterized in that: The circuit formed by connecting the upper bridge shutdown circuit of the auxiliary circuit in series with the upper bridge full-bridge circuit and the anode bus of the main circuit are connected through an isolating switch or a knife switch; the circuit formed by connecting the lower bridge shutdown circuit of the auxiliary circuit in series with the lower bridge full-bridge circuit and the cathode bus of the main circuit are connected through an isolating switch or a knife switch.

9. The full-bridge circuit shut-down grid-commutated converter according to claim 1, characterized in that: The upper bridge shutoff circuit and the lower bridge shutoff circuit both include a first fully controlled valve; One end of the first full-control valve of the upper bridge shut-off circuit is connected to one end of the upper bridge full-bridge circuit, and the other end of the first full-control valve of the upper bridge shut-off circuit is connected to the anode bus of the upper bridge transfer circuit; or, one end of the first full-control valve of the upper bridge shut-off circuit is connected to one end of the upper bridge full-bridge circuit, and the other end of the first full-control valve of the upper bridge shut-off circuit is connected to the anode bus of the main circuit; One end of the first full-control valve of the lower bridge shutdown circuit is connected to one end of the lower bridge full-bridge circuit, and the other end of the first full-control valve of the lower bridge shutdown circuit is connected to the cathode bus of the lower bridge transfer circuit; or, one end of the first full-control valve of the lower bridge shutdown circuit is connected to one end of the lower bridge full-bridge circuit, and the other end of the first full-control valve of the lower bridge shutdown circuit is connected to the cathode bus of the main circuit.

10. The full-bridge circuit shut-down grid-commutated converter according to claim 9, characterized in that: The upper bridge shutoff circuit and the lower bridge shutoff circuit both further include a fourth half-controlled valve connected in series with the first full-controlled valve.

11. The full-bridge circuit shut-down grid-commutated converter according to claim 9, characterized in that: The first full-control valve is connected in parallel with a lightning arrester.

12. The full-bridge circuit shut-down grid-commutated converter according to claim 9, characterized in that: The first full-control valve includes at least one of a one-way full-control switch, a two-way full-control switch, and a sub-module series switch.

13. The full-bridge circuit shut-down grid-commutated converter according to claim 12, characterized in that: The unidirectional fully controlled switch is composed of semiconductor devices with unidirectional shutoff capability connected in series, and the semiconductor devices with unidirectional shutoff capability include but are not limited to insulated gate bipolar transistors, integrated gate-commutated thyristors, and reverse-blocking integrated gate-commutated thyristors; The bidirectional fully-controlled switch is composed of semiconductor devices with bidirectional shutoff capability connected in series, and the semiconductor devices with bidirectional shutoff capability include but are not limited to anti-parallel reverse-resistance integrated gate-commutated thyristors and anti-series insulated gate bipolar transistors; 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 twin submodules. The semiconductor devices of the half-bridge submodules, full-bridge submodules, quasi-full-bridge submodules, and clamped twin submodules include but are not limited to insulated gate bipolar transistors and integrated gate-commutated thyristors.

14. The full-bridge circuit shut-down grid-commutated converter according to any one of claims 1 to 13, characterized in that: The upper bridge full bridge circuit and the lower bridge full bridge circuit both include: a second fully controlled valve; One end of the second fully-controlled valve of the upper bridge full-bridge circuit is connected to the anode bus of the main circuit, and the other end of the second fully-controlled valve of the upper bridge full-bridge circuit is connected to the upper bridge shut-off circuit; or, one end of the second fully-controlled valve of the upper bridge full-bridge circuit is connected to the anode bus of the upper bridge transfer circuit, and the other end of the second fully-controlled valve of the upper bridge full-bridge circuit is connected to the upper bridge shut-off circuit; One end of the second full-controlled valve of the lower bridge full-bridge circuit is connected to the cathode bus of the main circuit, and the other end of the second full-controlled valve of the lower bridge full-bridge circuit is connected to the lower bridge shutdown circuit; or, one end of the second full-controlled valve of the lower bridge full-bridge circuit is connected to the cathode bus of the lower bridge transfer circuit, and the other end of the second full-controlled valve of the lower bridge full-bridge circuit is connected to the lower bridge shutdown circuit.

15. The full-bridge circuit shut-down grid-commutated converter according to claim 14, characterized in that: The second fully-controlled valve includes at least one of a full-bridge submodule connected in series, a quasi-full-bridge submodule, a midpoint clamped submodule, a dual half-bridge series submodule, a dual full-bridge series submodule, a clamped twin submodule, a cross-connected twin submodule, a self-resistance submodule or a diode clamped submodule.

16. The full-bridge circuit shut-down grid-commutated converter according to claim 14, characterized in that: The upper full-bridge circuit and the lower full-bridge circuit further include a resistor or an inductor; the resistor or the inductor is connected in series with the submodule.

17. The full-bridge circuit shut-down grid-commutated converter according to claim 14, characterized in that: The second full-control valve is connected in parallel with a lightning arrester.

18. A full-bridge circuit shut-down grid commutation converter control method, characterized in that: Used to control the full-bridge circuit according to any one of claims 1 to 17 to shut down the grid-commutated converter, comprising: In the case of obtaining the operation parameter information of the full-bridge circuit shutting down the grid-commutated converter, generating the inverter state control information based on the parameter information, and controlling the main circuit to operate in the inverter state based on the inverter state control information; When the turn-off angle reference value is less than the minimum turn-off angle setting value or the commutation fault information is obtained, a circuit conduction instruction and negative voltage control information are generated during the commutation period, and the transfer circuit and the turn-off circuit in the auxiliary circuit corresponding to the commutation bridge arm are controlled to be turned on based on the circuit conduction instruction, and the full bridge circuit of the auxiliary circuit corresponding to the commutation bridge arm is controlled to present a negative voltage based on the negative voltage control information; When the first half-controlled valve of the commutation bridge arm of the main circuit is restored to be closed, a circuit closing instruction is generated to control the full-bridge circuit and / or the shut-off circuit corresponding to the commutation bridge arm to be shut down.

19. The method according to claim 18, characterized in that When the full-bridge circuit is shut down and the grid-commutating converter is operating normally, the shutdown angle reference value is set to be less than the minimum shutdown angle setting; when the shutdown angle reference value is obtained to be less than the minimum shutdown angle setting and the first half-controlled valve of the commutating bridge arm of the main circuit is restored to shutdown, the circuit shutdown instruction is generated, and based on the circuit shutdown instruction, only the full-bridge circuit corresponding to the commutating bridge arm is controlled to be shut down.

20. The method according to claim 18, characterized in that When the full-bridge circuit is shut down and the grid-commutating converter operates normally, the capacitor voltage of the sub-module of the full-bridge circuit of the auxiliary circuit is lower than the rated value and exceeds the first threshold, and the first half-controlled valve of the commutation bridge arm of the main circuit is restored to shutdown, the circuit shutdown instruction is generated in advance; and / or the number of sub-modules of the full-bridge circuit is increased; and / or the circuit conduction instruction for controlling the conduction of the corresponding transfer circuit and the shutdown circuit and the negative pressure control information for controlling the sub-module of the full-bridge circuit to present negative pressure are generated in advance; the value range of the first threshold is 0.01 to 0.6 times the rated capacitor voltage.

21. The method according to claim 18, characterized in that When the submodule capacitor voltage is greater than or equal to the rated value and exceeds the second threshold, and when the first half-controlled valve of the phase-changing bridge arm of the main circuit resumes shutdown, the generation of the circuit shutdown instruction is delayed; and / or the number of submodules of the full-bridge circuit is reduced; and / or the generation of the circuit conduction instruction for controlling the conduction of the corresponding transfer circuit and the shutdown circuit and the negative pressure control information for controlling the submodule of the full-bridge circuit to present negative pressure is delayed; the second threshold value range is 0.01 to 0.6 times the rated capacitor voltage.

22. The method according to claim 18, characterized in that Controlling the full-bridge circuit to present a negative pressure is achieved by controlling the switch device in the submodule of the third full-control valve to be turned on so that the submodule presents a capacitive negative pressure in the direction of current flow.

23. The method according to claim 18, characterized in that The recovery and shutdown of the first half-controlled valve of the commutation bridge arm of the main circuit is determined according to the reverse recovery time of the first half-controlled valve, and the reverse recovery time is greater than or equal to the reverse recovery time of the thyristor included in the first half-controlled valve.

24. The method according to any one of claims 18 to 23, characterized in that: The circuit after the upper bridge shutdown circuit of the auxiliary circuit is connected in series with the upper bridge full-bridge circuit and the anode bus of the main circuit are connected through an isolating switch or a knife switch, the circuit after the lower bridge shutdown circuit of the auxiliary circuit is connected in series with the lower bridge full-bridge circuit and the cathode bus of the main circuit are connected through an isolating switch and / or a knife switch, and a switch separation instruction is generated when the fault information of the auxiliary circuit is obtained, and the isolating switch or knife switch is controlled to separate based on the switch separation instruction.

25. A full-bridge circuit shut-down grid commutation converter control device, characterized in that: Used to control the full-bridge circuit according to any one of claims 1 to 17 to shut down the grid-commutated converter, comprising: A first control module is used to generate inverter state control information based on the parameter information when the operation parameter information of the full-bridge circuit shutting down the grid-commutated converter is obtained, and control the main circuit to operate in the inverter state based on the inverter state control information; a second control module, for generating a circuit conduction instruction and negative voltage control information during the commutation period when the turn-off angle reference value is less than the minimum turn-off angle setting value or the commutation fault information is obtained, and controlling the transfer circuit and the turn-off circuit in the auxiliary circuit corresponding to the commutation bridge arm to be turned on based on the circuit conduction instruction, and controlling the full bridge circuit of the auxiliary circuit corresponding to the commutation bridge arm to present a negative voltage based on the negative voltage control information; The third control module is used to generate a circuit shutdown instruction when the first half-controlled valve of the phase-changing bridge arm of the main circuit resumes shutdown, and control the full-bridge circuit and / or shutdown circuit corresponding to the phase-changing bridge arm to shut down.

26. A high voltage direct current transmission system, comprising the full bridge circuit shut down grid commutation converter according to any one of claims 1 to 17.

27. The system according to claim 26, 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, and 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.

28. The system according to claim 27, characterized in that The two-terminal DC power transmission system or the multi-terminal DC power transmission system requires some or all of the converters for inversion operation to shut down the grid commutation converter using the full-bridge circuit.

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