WO2023217218A1 - 双换流器并联电路及其控制方法和装置、直流输电系统 - Google Patents

双换流器并联电路及其控制方法和装置、直流输电系统 Download PDF

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Publication number
WO2023217218A1
WO2023217218A1 PCT/CN2023/093459 CN2023093459W WO2023217218A1 WO 2023217218 A1 WO2023217218 A1 WO 2023217218A1 CN 2023093459 W CN2023093459 W CN 2023093459W WO 2023217218 A1 WO2023217218 A1 WO 2023217218A1
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WIPO (PCT)
Prior art keywords
valve
converter
bridge arm
controlled
control
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
PCT/CN2023/093459
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English (en)
French (fr)
Inventor
卢东斌
卢宇
李海英
张庆武
周晨
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NR Electric Co Ltd
NR Engineering Co Ltd
Changzhou NR Electric Power Electronics Co Ltd
Original Assignee
NR Electric Co Ltd
NR Engineering Co Ltd
Changzhou NR Electric Power Electronics Co Ltd
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Publication of WO2023217218A1 publication Critical patent/WO2023217218A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
    • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
    • H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/145—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M7/155—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
    • H02M7/162—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only in a bridge configuration
    • H02M7/1623—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only in a bridge configuration with control circuit
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for AC mains or AC distribution networks
    • H02J3/36—Arrangements for transfer of electric power between AC networks via high-voltage DC [HVDC] links; Arrangements for transfer of electric power between generators and networks via HVDC links
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/06—Circuits specially adapted for rendering non-conductive gas discharge tubes or equivalent semiconductor devices, e.g. thyratrons, thyristors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H02M1/325—Means for protecting converters other than automatic disconnection with means for allowing continuous operation despite a fault, i.e. fault tolerant converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
    • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
    • H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/145—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M7/155—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
    • H02M7/162—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
    • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
    • H02M7/12—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/21—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/217—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M7/219—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/505—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
    • H02M7/515—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
    • H02M7/521—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H02M7/53875—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current with analogue control of three-phase output
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Definitions

  • This application relates to the technical field of high-voltage direct current transmission, specifically to double-converter parallel circuits and their control methods and devices, and direct current transmission systems.
  • the existing technology uses a grid commutation converter with a twelve-pulse circuit structure.
  • Each twelve-pulse circuit has two three-phase six-arm circuits connected in series, and each bridge arm uses a single large Capacity thyristors are connected in series. Since the thyristors cannot be controlled to turn off, the existing converter structure has the problem of commutation failure. At the same time, the cost of large-capacity thyristors is higher than that of small-capacity thyristors in parallel.
  • the voltage source converter for flexible DC transmission and hybrid DC transmission adopts a modular multi-level converter with a half-bridge structure or a full-bridge structure.
  • IGBT Insulated Gate Bipolar Transistor, Insulated Gate Bipolar Transistor
  • Type transistor Insulated Gate Bipolar Transistor
  • the embodiment of the present application provides a dual-converter parallel circuit, including a first converter, a second converter, and a connecting circuit.
  • the first converter is a three-phase six-arm circuit, including three first converters.
  • An upper bridge arm and three first lower bridge arms, each of the first upper bridge arm and the first lower bridge arm include a first half control valve and a first full control valve connected in series, the first The half-controlled valve includes a half-controlled switch, and the first full-controlled valve includes at least one of a one-way full-controlled switch, a two-way full-controlled switch, and an MMC single valve;
  • the second converter is a three-phase six-arm circuit, It includes three second upper bridge arms and three second lower bridge arms, each of the second upper bridge arms and the second lower bridge arms includes a second valve;
  • the connection circuit includes a third valve and a second lower bridge arm.
  • valves, the second valve, the third valve, and the fourth valve include at least one of an uncontrolled switch, a half-controlled switch, a one-way fully controlled switch, a two-way fully controlled switch, and an MMC single valve, wherein the third valve The valve connects the positive pole of the DC bus of the first converter or the first segmentation point of the first half-controlled valve of the first upper arm and the positive pole of the DC bus of the second converter, and the fourth valve connects The negative pole of the DC bus of the first converter or the second section of the first half-controlled valve of the first lower bridge arm point and the negative pole of the DC bus of the second converter; or the third valve is connected to the positive pole of the DC bus of the first converter or the first segmentation point of the first half-controlled valve of the first upper bridge arm and the negative pole of the DC bus of the second converter, and the fourth valve is connected to the negative pole of the DC bus of the first converter or the second segmentation point of the first half-controlled valve of the first lower arm and all The positive pole of the DC bus of the second
  • the first segmentation point divides the first half control valve of the first upper bridge arm into two segments according to the pressure resistance level
  • the second segmentation point divides the first half control valve of the first upper bridge arm into two segments according to the pressure resistance level.
  • the first half control valve of the lower bridge arm is divided into two sections, and the pressure ratio of the two sections ranges from 0.2 to 5.
  • the first segmentation point of the first half-controlled valve of each first upper bridge arm is connected to one of the third valves respectively.
  • lightning arresters are connected in parallel at both ends of the first half-controlled valve, the first full-controlled valve, the second valve, the third valve, and the fourth valve.
  • a second half-control valve is connected in parallel at both ends of the first full-control valve, and the second half-control valve includes a half-control switch.
  • connection circuit further includes a fifth valve, or a parallel circuit of the first capacitor and the first resistor, or a circuit of the parallel circuit and the fifth valve in series, connected to the second commutation
  • the first capacitor includes at least one capacitive element connected in series.
  • the connection circuit further includes a sixth valve and a seventh valve
  • the sixth valve connects the positive DC bus of the first converter and the positive DC bus of the second converter, so
  • the seventh valve connects the negative pole of the DC bus of the first converter and the negative pole of the DC bus of the second converter
  • the fifth valve, the sixth valve, and the seventh valve include an uncontrolled switch and a semi-controlled switch. , at least one of a one-way full control switch, a two-way full control switch, an MMC single valve, a series-connected full control switch and a quick isolation switch, both ends of the fifth valve, the sixth valve, the seventh valve, and the first capacitor Connect the arrester or/and the second half control valve in parallel respectively.
  • connection circuit further includes a lightning arrester, or a parallel circuit of a second capacitor and a second resistor, the lightning arrester is connected in series with the third valve or/and the fourth valve; the second capacitor and A parallel circuit of the second resistor is connected in series with the third valve or/and the fourth valve.
  • the AC output ends of the first converter and the second converter are connected in parallel by phase or connected in parallel by phase through an isolation switch or/and a knife switch, and are connected to the same converter transformer , the DC bus input ends of the first converter and the second converter are connected in parallel according to the positive and negative poles through an isolation switch or/and a knife switch.
  • An embodiment of the present application also provides a high-voltage direct current transmission system, including a double-converter parallel circuit as described above.
  • Embodiments of the present application also provide a control method for the dual-converter parallel circuit, including: controlling the first converter to operate in an inverter state; if the second valve includes a half-control switch, a one-way full-control switch, At least one of a control switch, a two-way full control switch, and an MMC single valve controls the second converter to operate in an inverter state or a blocking state; if the third valve and the fourth valve include a half control switch, a one-way At least one of a full control switch, a two-way full control switch, and an MMC single valve controls the third valve and the fourth valve to operate in a locked state; when a fault occurs, it may cause commutation of the first inverter.
  • the bridge arm commutation fails, including: if the second valve, the third valve, and the fourth valve include at least one of a half-control switch, a one-way full control switch, a two-way full control switch, and an MMC single valve, the control and all The corresponding bridge arm of the second converter corresponding to the commutation bridge arm and the third valve or the fourth valve are conductive; when the double converter parallel circuit also includes a fifth valve and the fifth valve
  • the valve includes at least one of a semi-control switch, a one-way full control switch, a two-way full control switch, and an MMC single valve, which controls the conduction of the fifth valve; and controls the first full control valve of the commutation bridge arm to turn off,
  • the current of the commutation bridge arm is transferred to the corresponding bridge arm of the second converter and the third valve or the fourth valve; after the first half-controlled valve of the commutation bridge arm is turned off, , if the second valve, the third valve, and the fourth valve include at least
  • the fifth valve is controlled to be turned off, so that the current flows from the commutation bridge arm.
  • the corresponding bridge arm of the second converter is a bridge arm connected to the DC bus of the same polarity and the same phase as the commutation bridge arm of the first converter.
  • the control method further includes: when the first full control valve controlling the commutation bridge arm is turned off, Lock the second converter and control the sixth valve or the seventh valve to turn off; after the working condition that may cause the commutation failure of the commutation bridge arm of the first converter disappears, control The sixth valve or/and the seventh valve are conductive.
  • the control method further includes: controlling the second converter to operate in a rectification state or a no-load pressurization state, as the The drive circuit of the fifth valve supplies power; when both ends of the fifth valve are connected in parallel with the second half-control valve, and the fifth valve has over-pressure, over-current or failure, the second half-control valve is controlled to be turned on; when the control The fifth valve is turned off.
  • the fifth valve is over-pressure, over-current or malfunctions, the first half-control valve and the first full-control valve that control the commutation bridge arm are turned on.
  • the control method further includes: controlling the sixth valve and the seventh valve to conduct, so that the The first converter and the second converter share a DC bus, so that the second converter runs in an inverter state; when the first full control valve, the second valve, the third valve, the fourth When the second half-controlled valve is connected in parallel at both ends of the valve, the sixth valve or the seventh valve, the first full-controlled valve, the second valve, the third valve, the fourth valve, the sixth valve or the seventh valve are over-pressured or over-pressured.
  • the second half-controlled valve When the flow or failure occurs, the second half-controlled valve is controlled to be turned on; when the corresponding bridge arm, third valve, fourth valve, sixth valve or seventh valve of the second converter is controlled to be turned off, the When the corresponding bridge arm of the second converter, the third valve or the fourth valve, the sixth valve or the seventh valve has over-pressure, over-flow or failure, the first half-controlled valve and the first half-controlled valve of the commutation bridge arm are controlled. Full control valve conduction.
  • Embodiments of the present application also provide a control device for a dual-converter parallel circuit as described above, including a detection unit and a control unit.
  • the detection unit is used to detect operating parameters and faults of the dual-converter parallel circuit;
  • the control unit controls the first converter to operate in the inverter state based on the operating parameters of the dual-converter parallel circuit; if the second valve includes a half-control switch, a one-way full control switch, and a two-way full control switch, At least one of a control switch and an MMC single valve controls the second inverter to operate in an inverter state or a blocking state; if the third valve and the fourth valve include a half control switch, a one-way full control switch, a two-way At least one of a full control switch and an MMC single valve controls the third valve and the fourth valve to operate in a locked state.
  • the second valve, the third valve, and the fourth valve include at least one of a half-control switch, a one-way full control switch, a two-way full control switch, and an MMC single valve.
  • the control unit also controls the commutation bridge arm corresponding to the The corresponding bridge arm of the second converter and the third valve or the fourth valve are connected, when the double converter parallel circuit also includes a fifth valve and the fifth valve includes a half-control switch, At least one of a one-way full control switch, a two-way full control switch, and an MMC single valve controls the conduction of the fifth valve; controls the first full control valve of the commutation bridge arm to turn off, so that the commutation bridge The current of the arm is transferred to the corresponding bridge arm of the second converter and the third valve or the fourth valve.
  • the first half-controlled valve of the commutation bridge arm is turned off, if the second The valve, the third valve, and the fourth valve include at least one of a one-way full control switch, a two-way full control switch, and an MMC single valve, and control the corresponding bridge arm of the second converter, the third valve, or the The fourth valve is turned off, if the second valve, the third valve, and the fourth valve only include at least one of an uncontrolled switch and a semi-controlled switch, and when the double converter parallel circuit also includes a fifth valve and all The fifth valve includes at least one of a one-way full control switch, a two-way full control switch, and an MMC single valve.
  • the fifth valve is controlled to be turned off, thereby realizing the current transfer from the phase where the commutation bridge arm is located to another phase.
  • the corresponding bridge arm of the second converter is a bridge arm connected to the same polarity DC bus and the same phase as the commutation bridge arm of the first converter.
  • the bridge arm circuit and the connecting circuit of the second converter form a parallel circuit with the bridge arm circuit of the first converter, and the first full control valve switch of the first converter is used for commutation.
  • the first converter based on the half-controlled device is realized. Controllable commutation effectively suppresses commutation failure.
  • the double converter composed of the first converter and the second converter can operate in parallel, which increases the capacity of the double converter and increases the redundancy of the system. .
  • Figure 1 is one of the schematic diagrams of a double-converter parallel circuit provided by an embodiment of the present application.
  • Figure 2 is the second schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 3 is the third schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 4 is the fourth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • FIG. 5 is a fifth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 6 is the sixth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • FIGS 7a-7k are schematic diagrams of valve structures provided by embodiments of the present application.
  • FIG. 8 is the seventh schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 9 is the eighth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 10 is a ninth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 11 is a schematic diagram of a dual-converter parallel circuit provided by the embodiment of the present application.
  • Figure 12 is an eleventh schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 13 is the twelfth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 14 is the thirteenth schematic diagram of a dual-converter parallel circuit provided by the embodiment of the present application.
  • Figure 15 is a fourteenth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 16 is a schematic flowchart of a control method for a dual-converter parallel circuit according to an embodiment of the present application.
  • Figure 17a is a single-phase ground fault test result of a double-converter parallel circuit according to an embodiment of the present application
  • Figure 17b is a three-phase ground fault test result of a double-converter parallel circuit according to an embodiment of the present application.
  • Figure 18a is the single-phase ground fault test result of another double-converter parallel circuit according to the embodiment of the present application
  • Figure 18b is the three-phase ground fault test result of another double-converter parallel circuit according to the embodiment of the present application. .
  • Figure 19 is a schematic diagram of a control device for a dual-converter parallel circuit provided by an embodiment of the present application.
  • Figure 1 is one of the schematic diagrams of a double-converter parallel circuit provided by an embodiment of the present application.
  • the double-converter parallel circuit includes a first converter 1, a second converter 2 and a connecting circuit.
  • the first converter 1 includes three-phase six bridge arms, which are three first upper bridge arms and three first lower bridge arms. Each first upper bridge arm and first lower bridge arm include a third bridge arm connected in series. Half control valve and first full control valve.
  • the first upper bridge arm of phase A includes a first half control valve V41 and a first full control valve V42 connected in series
  • the first upper bridge arm of phase B includes a first half control valve V61 and a first full control valve V62 connected in series
  • the C-phase first upper bridge arm includes a first half-control valve V21 and a first full-control valve V22 connected in series.
  • the A-phase first lower bridge arm includes a series-connected first half-control valve V11 and a first full-control valve V12
  • the B-phase first lower bridge arm includes a series-connected first half-control valve V31 and a first full-control valve V32
  • the C-phase first lower bridge arm includes a first half-control valve V51 and a first full-control valve V52 connected in series.
  • the second converter 2 includes three-phase six bridge arms, including three second upper bridge arms and three second lower bridge arms.
  • Each second upper bridge arm and second lower bridge arm includes a second valve.
  • the second upper bridge arm of phase A includes the second valve V43
  • the second upper bridge arm of phase B includes the second valve V63
  • the second upper bridge arm of phase C includes the second valve V23
  • the second lower bridge arm of phase A includes the second valve V13
  • the B-phase second lower bridge arm includes the second valve V33
  • the C-phase second lower bridge arm includes the second valve V53.
  • the connection circuit includes a third valve V71 and a fourth valve V72.
  • the third valve V71 connects the DC bus positive pole P1 of the first converter 1 and the DC bus positive pole P2 of the second converter 2
  • the fourth valve V72 connects the DC bus negative pole N1 of the first converter 1 and the second converter
  • the negative pole N2 of the DC bus of device 2 is as shown in Figure 1.
  • the third valve V71 is connected to the DC bus positive pole P1 of the first converter 1 and the DC bus negative pole N2 of the second converter 2
  • the fourth valve V72 is connected to the DC bus negative pole N1 of the first converter 1 and the positive pole P2 of the DC bus of the second converter 2, as shown in Figure 2.
  • Figure 3 is the third schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application. As shown in Figure 3, double swap The converter parallel circuit includes a first converter 1, a second converter 2 and a connecting circuit.
  • the first converter 1 includes three-phase six bridge arms, which are three first upper bridge arms and three first lower bridge arms. Each first upper bridge arm and first lower bridge arm include a third bridge arm connected in series. Half control valve and first full control valve.
  • the first upper bridge arm of phase A includes a first half control valve V41 and a first full control valve V42 connected in series
  • the first upper bridge arm of phase B includes a first half control valve V61 and a first full control valve V62 connected in series
  • the C-phase first upper bridge arm includes a first half-control valve V21 and a first full-control valve V22 connected in series.
  • the A-phase first lower bridge arm includes a series-connected first half-control valve V11 and a first full-control valve V12
  • the B-phase first lower bridge arm includes a series-connected first half-control valve V31 and a first full-control valve V32
  • the C-phase first lower bridge arm includes a first half-control valve V51 and a first full-control valve V52 connected in series.
  • the second converter 2 includes three-phase six bridge arms, including three second upper bridge arms and three second lower bridge arms.
  • Each second upper bridge arm and second lower bridge arm includes a second valve.
  • the second upper bridge arm of phase A includes the second valve V43
  • the second upper bridge arm of phase B includes the second valve V63
  • the second upper bridge arm of phase C includes the second valve V23
  • the second lower bridge arm of phase A includes the second valve V13
  • the B-phase second lower bridge arm includes the second valve V33
  • the C-phase second lower bridge arm includes the second valve V53.
  • the connection circuit includes third valves V71, V81, V91 and fourth valves V72, V82, V92.
  • the third valve V71 connects the first staging point of the first half-control valve V41 and the DC bus positive pole P2 of the second converter 2 .
  • the third valve V81 connects the first staging point of the first half-control valve V61 and the DC bus positive pole P2 of the second converter 2 .
  • the third valve V91 connects the first staging point of the first half-control valve V21 and the DC bus positive pole P2 of the second converter 2 .
  • the fourth valve V72 connects the second staging point of the first half-controlled valve V11 and the DC bus negative pole N2 of the second converter 2 .
  • the fourth valve V82 connects the second staging point of the first half-control valve V31 and the DC bus negative pole N2 of the second converter 2 .
  • the fourth valve V92 connects the second staging point of the first half-control valve V51 and the DC bus negative pole N2 of the second converter 2 .
  • the third valve V71 connects the first segmentation point of the first half-control valve V41 and the DC bus negative pole N2 of the second converter 2, and the third valve V81 connects the first segmentation point of the first half-control valve V61.
  • the segment point is connected to the negative pole N2 of the DC bus of the second converter 2.
  • the third valve V91 is connected to the first segment point of the first half-controlled valve V21 and the negative pole N2 of the DC bus of the second converter 2.
  • the fourth valve V72 is connected.
  • the second segmentation point of the first half-control valve V11 and the DC bus positive P2 of the second converter 2 are connected.
  • the fourth valve V82 connects the second segmentation point of the first half-control valve V31 and the second segmentation point of the second converter 2.
  • the DC bus positive pole P2 and the fourth valve V92 connect the second segmentation point of the first half-controlled valve V51 and the DC bus positive pole P2 of the second converter 2, as shown in Figure 4.
  • the second valve, the third valve, and the fourth valve include at least uncontrolled switches, semi-controlled switches, one-way fully controlled switches, two-way fully controlled switches, and MMC (Modular Multilevel Converter, modular multilevel converter) single valves.
  • MMC Modular Multilevel Converter, modular multilevel converter
  • FIG. 5 is a fifth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application. As shown in Figure 5, the double-converter parallel circuit includes a first converter 1, a second converter 2 and a connecting circuit.
  • the first converter 1 includes three-phase six bridge arms, which are three first upper bridge arms and three first lower bridge arms. Each first upper bridge arm and first lower bridge arm include a third bridge arm connected in series. Half control valve and first full control valve.
  • the first upper bridge arm of phase A includes a first half control valve V41 and a first full control valve V42 connected in series
  • the first upper bridge arm of phase B includes a first half control valve V61 and a first full control valve V62 connected in series
  • the C-phase first upper bridge arm includes a first half-control valve V21 and a first full-control valve V22 connected in series.
  • the A-phase first lower bridge arm includes a series-connected first half-control valve V11 and a first full-control valve V12
  • the B-phase first lower bridge arm includes a series-connected first half-control valve V31 and a first full-control valve V32
  • the C-phase first lower bridge arm includes a first half-control valve V51 and a first full-control valve V52 connected in series.
  • the second converter 2 includes three-phase six bridge arms, including three second upper bridge arms and three second lower bridge arms.
  • Each second upper bridge arm and second lower bridge arm includes a second valve.
  • the second upper bridge arm of phase A includes the second valve V43
  • the second upper bridge arm of phase B includes the second valve V63
  • the second upper bridge arm of phase C includes the second valve V23
  • the second lower bridge arm of phase A includes the second valve V13
  • the B-phase second lower bridge arm includes the second valve V33
  • the C-phase second lower bridge arm includes the second valve V53.
  • the connection circuit includes a third valve V71, a fourth valve V72, and a fifth valve V73.
  • the third valve V71 connects the DC bus positive pole P1 of the first converter 1 and the DC bus negative pole N2 of the second converter 2
  • the fourth valve V72 connects the DC bus negative pole N1 of the first converter 1 and the second converter
  • the DC bus positive pole P2 of the converter 2 and the fifth valve V73 is connected to the DC bus positive pole P2 and the DC bus negative pole N2 of the second converter 2, as shown in Figure 5.
  • connection circuit further includes a sixth valve V74 and a seventh valve V75.
  • the sixth valve V74 connects the DC bus positive P1 of the first converter 1 and the DC bus positive P2 of the second converter 2
  • the seventh valve V75 connects the DC bus negative N1 of the first converter 1 and the second converter
  • the negative pole N2 of the DC bus of device 2 is shown in Figure 6.
  • the fifth valve V73 may also be replaced by a parallel circuit of a first capacitor and a first resistor, or a parallel circuit of a first capacitor and a first resistor and a series circuit of the fifth valve V73.
  • the first capacitor includes at least one capacitive element connected in series, but is not limited to this.
  • resistors and inductors are also connected in series.
  • the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, and the seventh valve include at least one of an uncontrolled switch, a half-controlled switch, a one-way fully controlled switch, a two-way fully controlled switch, and an MMC single valve. , but not limited to this.
  • the fully controlled switch includes at least one fully controlled device connected in series, and the fully controlled device includes IGCT (Integrated Gate Commutated Thyristors), IGBT, GTO (Gate Turn-Off Thyristor) , at least one of a gate-turn-off thyristor) and a MOSFET (Metal Oxide Semiconductor Field Effect Transistor, a metal-oxide semiconductor field effect transistor);
  • the half-controlled switch includes at least one half-controlled device connected in series, and the half-controlled switch
  • the controlled device includes a thyristor;
  • the uncontrolled switch includes at least one uncontrolled device connected in series, and the uncontrolled device includes a diode.
  • an uncontrolled switch includes a diode 3 connected in series, as shown in Figure 7a, which cannot be controlled to turn on and off, and has unidirectional current flow capability and unidirectional blocking voltage capability.
  • a semi-controlled switch includes thyristors 4 connected in series, as shown in Figure 7b, which can only control on, but cannot control off, and has unidirectional current flow capability and bidirectional blocking voltage capability.
  • the half-controlled switch is composed of a thyristor 4 and a diode 3 connected in series or in parallel.
  • a one-way fully controlled switch includes an IGBT module connected in series.
  • the IGBT module includes an IGBT 5 and a diode 3 connected in anti-parallel with it. As shown in Figure 7c, it only controls turning on and off in one direction, and has bidirectional switching. current and unidirectional blocking voltage capabilities.
  • a one-way fully controlled switch includes series-connected IGCTs 6, as shown in Figure 7d, which only controls on and off in one direction, and has one-way current flow and two-way blocking voltage capabilities.
  • a one-way fully controlled switch includes an IGBT module and a diode 3 connected in series, as shown in Figure 7e, which only controls on and off in one direction, and has one-way current flow and two-way blocking voltage capabilities.
  • a one-way fully controlled switch includes an IGCT6 and a thyristor 4 connected in anti-parallel and then connected in series, as shown in Figure 7f. It has bidirectional control on and unidirectional control off, and has bidirectional current flow and bidirectional blocking voltage capabilities.
  • a bidirectional fully controlled switch includes a forward IGBT module and a reverse IGBT module connected in series, as shown in Figure 7g, which can bidirectionally control on and off, and has bidirectional current flow capability and bidirectional blocking voltage capability. .
  • a bidirectional fully controlled switch includes a series circuit in which a forward IGCT6 and a reverse IGCT6 are connected in parallel, as shown in Figure 7h, which can bidirectionally control on and off, and has bidirectional current flow capability and bidirectional blocking voltage capability. .
  • an MMC single valve includes submodules connected in series.
  • the submodule includes two IGBT modules and a capacitor 7. As shown in Figure 7i, the connection point of the two IGBT modules serves as the positive electrode of the submodule, and one IGBT The other end of the module serves as the negative pole of the sub-module.
  • the sub-modules are connected in series and can only control on and off in one direction. They have bidirectional current flow capabilities and unidirectional blocking voltage capabilities.
  • an MMC single valve includes sub-modules connected in series.
  • the sub-modules include four IGBT modules and a capacitor 7. As shown in Figure 7j, the IGBT modules are connected in series and then in parallel, and are also connected in parallel with the capacitor 7. , the connection points of two IGBT modules connected in series serve as the positive and negative poles of the sub-modules respectively.
  • the sub-modules are connected in series and can be turned on and off in two directions. They have bidirectional current flow capabilities and bidirectional blocking voltage capabilities.
  • the fifth valve, the sixth valve, and the seventh valve include a full control switch and a quick isolation switch connected in series. As shown in Figure 7k, the full control switch and the quick isolation switch 8 are connected in series. The quick isolating switch 8 provides a sufficient pressure resistance level, reducing the on-state loss of the fifth valve, the sixth valve, and the seventh valve and the pressure resistance level of the full control switch. It should be pointed out that the IGBTs in Figures 7c, 7e, 7g, 7i, 7j and 7k can be IGCT, GTO, or MOSFET.
  • the thyristor 4 is configured with a corresponding trigger circuit; the IGBT5 is configured with a corresponding drive circuit and a buffer circuit; and the IGCT6 is configured with a corresponding drive circuit and a buffer circuit.
  • the buffer circuit consists of at least a capacitor, or a series circuit of a resistor and a capacitor.
  • lightning arresters may be connected in parallel at both ends of the first half-controlled valve, the first full-controlled valve, the second valve, the third valve, the fourth valve, the fifth valve, the sixth valve, the seventh valve, and the first capacitor. or/and second half control valve. If the first half-controlled valve is divided into sections, arresters can be connected in parallel at both ends of the two sections. If the fifth valve includes a half-control switch and a full-control switch, and the two are connected in series, then the half-control switch and the full-control switch are connected in parallel to arresters respectively.
  • both ends of the first full control valve may be connected in parallel with the second half control valve.
  • the third valve V71 is also connected in series with a lightning arrester and then connected to the DC bus positive electrode P1 of the first converter 1, the DC bus positive electrode P2 of the second converter 2, or the DC bus negative electrode N2 of the second converter 2.
  • the fourth valve V72 is also connected in series with a lightning arrester and then connected to the negative DC bus N1 of the first converter 1, the negative DC bus N2 of the second converter 2, or the positive DC bus P2 of the second converter 2.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 of the first converter 1 are connected in parallel with the first arresters F11, F21, F31, F41, F51 and F61 respectively.
  • the first full control valves V12, V22, V32, V42, V52 and V62 of the device 1 are respectively connected in parallel with the second arresters F12, F22, F32, F42, F52 and F62.
  • the second valves V13, V23, V33, V43, V53 and V63 of the second converter 2 are respectively connected in parallel with the third arresters F13, F23, F33, F43, F53 and F63.
  • the third valve V71 is connected in parallel with the fourth arrester F71
  • the fourth valve V72 is connected in parallel with the fifth arrester F72
  • the third valve V71 is connected in series with the sixth arrester F76
  • the fourth valve V72 is connected in series with the seventh arrester F77.
  • the voltage withstand levels of the second arresters F12, F22, F32, F42, F52 and F62 are higher than those of the sixth arrester F76 and the seventh arrester F77. It should be pointed out that the sixth arrester F76 and the seventh arrester F77 do not have to be connected in series. If the first half-controlled valve is divided into two sections, the first arrester should also be divided into two sections, and be connected in parallel with the two sections of the first half-controlled valve respectively.
  • the third valve V71 is also connected in series with the parallel circuit of the second capacitor and the second resistor and then connected with the DC bus positive electrode P1 of the first converter 1, the DC bus positive electrode P2 of the second converter 2 or the third valve V71.
  • the negative pole N2 of the DC bus of the second converter 2 is connected.
  • the fourth valve V72 is also connected in series with the parallel circuit of the second capacitor and the second resistor and then connected to the negative pole N1 of the DC bus of the first converter 1 and the second converter 2
  • the negative pole N2 of the DC bus or the positive pole P2 of the DC bus of the second converter 2 is connected.
  • the AC output terminals of the first converter 1 and the second converter 2 may be connected in parallel by phase, that is, A1 and A2 are connected, B1 and B2 are connected, C1 and C2 are connected, and they are respectively connected to the three phases of the same converter transformer.
  • Figure 9 is the eighth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • the double-converter parallel circuit includes a first converter 1, a second converter 2 and a connecting circuit.
  • the AC output terminals of the first inverter 1 and the second inverter 2 are connected in parallel according to phases, that is, A1 and A2 are connected, B1 and B2 are connected, and C1 and C2 are connected. , and connected to the three phases of the same converter transformer, as shown in Figure 9.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 respectively include half-controlled switches composed of thyristors 4 connected in series
  • the first full-controlled valves V12, V22, V32, V42, V52 and V62 respectively It includes a one-way full control switch, which is composed of IGBT modules connected in series.
  • the second valves V13, V23, V33, V43, V53 and V63 respectively include half-controlled switches and are composed of 4 thyristors connected in series.
  • the third valve V71 includes a one-way full control switch. It is composed of IGBT modules connected in series.
  • the fourth valve V72 includes a one-way full control switch and is composed of IGBT modules connected in series.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 of the first converter 1 are respectively connected in parallel with the first arresters F11, F21, F31, F41, F51 and F61.
  • the first converter The first full control valves V12, V22, V32, V42, V52 and V62 of 1 are respectively connected in parallel with the second arresters F12, F22, F32, F42, F52 and F62.
  • the second valves V13, V23, V33, V43, V53 and V63 of the second converter 2 are respectively connected in parallel with the third arresters F13, F23, F33, F43, F53 and F63.
  • the third valve V71 is connected in parallel with the fourth arrester F71
  • the fourth valve V72 is connected in parallel with the fifth arrester F72, as shown in Figure 9.
  • Figure 10 is a ninth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • the double-converter parallel circuit includes a first converter 1, a second converter 2 and a connecting circuit.
  • the AC output terminals of the first inverter 1 and the second inverter 2 are connected in parallel according to phases, that is, A1 and A2 are connected, B1 and B2 are connected, and C1 and C2 are connected. , and connected to the three phases of the same converter transformer, as shown in Figure 10.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 respectively include half-controlled switches composed of thyristors 4 connected in series
  • the first full-controlled valves V12, V22, V32, V42, V52 and V62 respectively It includes a one-way fully controlled switch, which is composed of IGBT modules connected in series.
  • the second valves V13, V23, V33, V43, V53 and V63 respectively include uncontrolled switches and are composed of diodes 3 connected in series.
  • the third valve V71 includes a half-controlled switch V711 and a single
  • the full control switch V712 and the half control switch V711 are composed of 4 thyristors connected in series.
  • the one-way full control switch V712 is composed of an IGBT module connected in series.
  • the fourth valve V72 includes the half-controlled switch V721 and the one-way full control switch V722 connected in series.
  • the switch V721 is composed of 4 thyristors connected in series
  • the one-way full control switch V722 is composed of IGBT modules connected in series. It should be pointed out that the half-controlled switch of the third valve V71 or the fourth valve V72 is used to provide positive pressure resistance and can be replaced by a one-way full-controlled switch. Therefore, the third valve V71 or the fourth valve V72 can also be entirely made of Composed of one-way full control switch.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 of the first converter 1 are respectively connected in parallel with the first arresters F11, F21, F31, F41, F51 and F61.
  • the first full control valves V12, V22, V32, V42, V52 and V62 of 1 are respectively connected in parallel with the second arresters F12, F22, F32, F42, F52 and F62.
  • the second valves V13, V23, V33, V43, V53 and V63 of the second converter 2 are respectively connected in parallel with the third arresters F13, F23, F33, F43, F53 and F63.
  • the half-controlled switch V711 of the third valve V71 is connected in parallel with the arrester F711
  • the one-way full control switch V712 is connected in parallel with the fourth arrester F71
  • the half-controlled switch V721 of the fourth valve V72 is connected in parallel with the arrester F721
  • the one-way full control switch V722 is connected in parallel with the fifth arrester F72. As shown in Figure 10.
  • Figure 11 is a schematic diagram of a dual-converter parallel circuit provided by the embodiment of the present application.
  • the third valve V71 is connected to the DC bus of the first converter 1
  • the positive electrode P1 and the DC bus negative electrode N2 of the second converter 2 are connected.
  • the fourth valve V72 connects the DC bus negative electrode N1 of the first converter 1 and the DC bus positive electrode P2 of the second converter 2 .
  • the fifth valve V73 connects the DC bus positive pole P2 and the DC bus negative pole N2 of the second converter 2 .
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 respectively include half-controlled switches, which are composed of 4 thyristors connected in series.
  • the first full-controlled valves V12, V22, V32, V42, V52 and V62 respectively include one-way full-controlled switches.
  • the switch is composed of IGBT modules connected in series.
  • the second valves V13, V23, V33, V43, V53 and V63 respectively include half-controlled switches and are composed of 4 thyristors connected in series.
  • the third valve V71 includes uncontrolled switches and are composed of 3 diodes connected in series.
  • the four-valve V72 includes an uncontrolled switch and is composed of three diodes connected in series.
  • the fifth valve V73 includes a one-way fully controlled switch and is composed of IGBT modules connected in series.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 of the first converter 1 are respectively connected in parallel with the first arresters F11, F21, F31, F41, F51 and F61.
  • the first full control valves V12, V22, V32, V42, V52 and V62 of the converter 1 are respectively connected in parallel with the second arresters F12, F22, F32, F42, F52 and F62.
  • the second valves V13, V23, V33, V43, V53 and V63 of the second converter 2 are respectively connected in parallel with the third arresters F13, F23, F33, F43, F53 and F63.
  • the third valve V71 is connected in parallel with the fourth arrester F71
  • the fourth valve V72 is connected in parallel with the fifth arrester F72
  • the fifth valve V73 is connected in parallel with the eighth arrester F73.
  • the AC output terminals of the first converter 1 and the second converter 2 are connected in parallel according to phases, that is, A1 and A2 are connected, B1 and B2 are connected, C1 and C2 are connected, and they are connected to the three phases of the same converter transformer.
  • Figure 12 is an eleventh schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • the third valve V71 is connected to the DC bus positive pole P1 of the first converter 1 and the DC bus negative pole N2 of the second converter 2
  • the fourth valve V72 is connected to the DC bus cathode N2 of the second converter 2.
  • the fifth valve V73 connects the DC bus positive pole P2 and the DC bus negative pole N2 of the second converter 2 .
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 respectively include half-controlled switches, which are composed of 4 thyristors connected in series.
  • the first full-controlled valves V12, V22, V32, V42, V52 and V62 respectively include one-way full-controlled switches.
  • the switch is composed of IGBT modules connected in series.
  • the second valves V13, V23, V33, V43, V53 and V63 respectively include uncontrolled switches and are composed of 3 diodes connected in series.
  • the third valve V71 includes uncontrolled switches and are composed of 3 diodes connected in series.
  • the four-valve V72 includes an uncontrolled switch and is composed of 3 diodes connected in series.
  • the fifth valve V73 includes a half-controlled switch V731 and a one-way full-controlled switch V732.
  • the half-controlled switch V731 is composed of 4 thyristors connected in series
  • the one-way full-controlled switch V732 is composed of an IGBT module. Composed in series. It should be pointed out that the fifth valve V73 can also be entirely composed of one-way full control switches.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 of the first converter 1 are respectively connected in parallel with the first arresters F11, F21, F31, F41, F51 and F61.
  • the first full control valves V12, V22, V32, V42, V52 and V62 of the converter 1 are respectively connected in parallel with the second arresters F12, F22, F32, F42, F52 and F62.
  • the second valves V13, V23, V33, V43, V53 and V63 of the second converter 2 are respectively connected in parallel with the third arresters F13, F23, F33, F43, F53 and F63.
  • the third valve V71 is connected in parallel with the fourth arrester F71
  • the fourth valve V72 is connected in parallel with the fifth arrester F72
  • the half-controlled switch V731 of the fifth valve V73 is connected in parallel with the arrester F731
  • the one-way full control switch V732 of the fifth valve V73 is connected in parallel with the eighth arrester F73.
  • the AC output terminals of the first converter 1 and the second converter 2 are connected in parallel according to phases, that is, A1 and A2 are connected, B1 and B2 are connected, C1 and C2 are connected, and they are connected to the three phases of the same converter transformer.
  • Figure 13 is the twelfth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • the third valve V71 is connected to the DC bus positive pole P1 of the first inverter 1 and the DC bus negative pole N2 of the second inverter 2
  • the fourth valve V72 is connected to the DC bus cathode N2 of the second converter 2.
  • the fifth valve V73 connects the DC bus positive pole P2 and the DC bus negative pole N2 of the second converter 2 .
  • the two ends of the first full control valves V12, V22, V32, V42, V52 and V62 are respectively connected in parallel with the second half control valves V14, V24, V34, V44, V54 and V64.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 respectively include half-controlled switches, which are composed of 4 thyristors connected in series.
  • the first full-controlled valves V12, V22, V32, V42, V52 and V62 respectively include one-way full-controlled switches.
  • the switch is composed of IGBT modules connected in series.
  • the second valves V13, V23, V33, V43, V53 and V63 respectively include half-controlled switches and are composed of 4 thyristors connected in series.
  • the third valve V71 includes half-controlled switches and are composed of 4 thyristors connected in series.
  • the four-valve V72 includes a half-controlled switch, which is composed of 4 thyristors connected in series.
  • the fifth valve V73 includes a one-way full-controlled switch, which is composed of an IGBT module connected in series.
  • the second half-controlled valves V14, V24, V34, V44, V54 and V64 respectively include half-controlled switches.
  • the control switch is composed of 4 thyristors connected in series.
  • the second valve may also include an uncontrolled switch composed of diodes 3 connected in series.
  • Figure 14 is the thirteenth schematic diagram of a dual-converter parallel circuit provided by the embodiment of the present application.
  • the third valve V71 is connected to the DC bus positive pole P1 of the first inverter 1 and the DC bus negative pole N2 of the second inverter 2
  • the fourth valve V72 is connected to the DC bus cathode N2 of the second converter 2.
  • the fifth valve V73 connects the DC bus positive pole P2 and the DC bus negative pole N2 of the second converter 2 .
  • the sixth valve V74 connects the DC bus positive P1 of the first converter 1 and the DC bus positive P2 of the second converter 2
  • the seventh valve V75 connects the DC bus negative N1 of the first converter 1 and the second converter The negative pole N2 of the DC bus of device 2.
  • the fifth valve V73 is connected in parallel with the eighth arrester F73
  • the sixth valve V74 is connected in parallel with the ninth arrester F74
  • the seventh valve V75 is connected in parallel with the tenth arrester F75.
  • the AC output terminals of the first converter 1 and the second converter 2 are connected in parallel by phase through isolation switches or/and knife switches S13, S14, S15, S23, S24 and S25, and are connected to the terminals of the same converter transformer. Three phases.
  • the DC bus input end of the first converter 1 passes through the isolating switch or/and the knife switches S10 and S20 and the DC bus input end of the second converter 2 passes through the isolating switch or/and the knife gates S12 and S21 and is connected in parallel according to the positive and negative poles. connect.
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 respectively include half-controlled switches, which are composed of 4 thyristors connected in series.
  • the first full-controlled valves V12, V22, V32, V42, V52 and V62 respectively include one-way full-controlled switches.
  • the switch is composed of IGBT modules connected in series.
  • the second valves V13, V23, V33, V43, V53 and V63 respectively include half-controlled switches and are composed of 4 thyristors connected in series.
  • the third valve V71 includes half-controlled switches and are composed of 4 thyristors connected in series.
  • the four-valve V72 includes a half-control switch and is composed of 4 thyristors connected in series.
  • the fifth valve V73 includes a one-way full control switch and is composed of IGBT modules connected in series.
  • the sixth valve V74 includes a one-way full control switch and is composed of IGBT modules connected in series.
  • Valve V75 includes a one-way fully controlled switch composed of IGBT modules connected in series.
  • Figure 15 is a fourteenth schematic diagram of a dual-converter parallel circuit provided by an embodiment of the present application.
  • the third valve V71 is connected to the DC bus positive pole P1 of the first converter 1 and the DC bus negative pole N2 of the second converter 2
  • the fourth valve V72 is connected to the DC bus cathode N2 of the second converter 2.
  • the fifth valve is replaced by a parallel circuit of the first capacitor C11 and the first resistor R11.
  • the parallel circuit of the first capacitor C11 and the first resistor R11 is connected in series to the DC bus positive electrode P2 and the DC bus negative electrode N2 of the second converter 2 .
  • the first capacitor C11 is connected in parallel with the eleventh arrester F78.
  • the AC output terminals of the first converter 1 and the second converter 2 are connected in parallel according to phases, that is, A1 and A2 are connected, B1 and B2 are connected, C1 and C2 are connected, and they are respectively connected to the three phases of the same converter transformer. .
  • the first half-controlled valves V11, V21, V31, V41, V51 and V61 respectively include half-controlled switches, which are composed of 4 thyristors connected in series.
  • the first full-controlled valves V12, V22, V32, V42, V52 and V62 respectively include one-way full-controlled switches.
  • the switch is composed of IGBT modules connected in series.
  • the second valves V13, V23, V33, V43, V53 and V63 respectively include half-controlled switches and are composed of 4 thyristors connected in series.
  • the third valve V71 includes a one-way full-controlled switch composed of IGCT6 and thyristor 4. It is composed of parallel connection and then series connection.
  • the fourth valve V72 includes a one-way full control switch, which is composed of IGCT6 and thyristor 4 connected in parallel and then series connection.
  • the first capacitor C11 is composed of capacitance elements connected in series.
  • Embodiments of the present application also provide a high-voltage direct current transmission system.
  • the high-voltage direct current transmission system includes a double-converter parallel circuit as described above.
  • Figure 16 is a schematic flowchart of a control method for a dual-converter parallel circuit provided by an embodiment of the present application, including the following processes.
  • the first converter is controlled to operate in the inverter state.
  • the first full control valve of the first converter is turned off after the first half control valve is turned off.
  • the first full control valve V42 of the first converter 1 is in Half of the control valve V41 is turned off and then turned off again.
  • first full control valve is also connected in parallel with the second half control valve, when the first full control valve has overpressure, overflow or failure, the second half control valve is controlled to conduct.
  • first full control valve V42 has over-pressure, over-current or failure
  • the second half-control valve V44 is controlled to conduct.
  • the second inverter is controlled to run in an inverter state or a blocking state.
  • the second valve includes a half-controlled switch.
  • the second converter operates in the inverter state; otherwise, the second converter operates in the blocking state.
  • the second converter operates in an uncontrolled state.
  • the third valve and the fourth valve include at least one of a half control switch, a one-way full control switch, a two-way full control switch, and an MMC single valve, the third valve and the fourth valve are controlled to operate in a locked state. .
  • the parallel circuit of the double converter also includes a fifth valve
  • the fifth valve is a one-way full control switch, a two-way full control switch or an MMC single valve
  • the third valve and the fourth valve are selected.
  • the third valve and the fourth valve are uncontrolled switches, the third valve and the fourth valve operate in an uncontrolled state.
  • the third valve V71 and the fourth valve V72 at least include full control switches to control the third valve and the fourth valve to operate in a locked state.
  • the third valve V71 and the fourth valve V72 use uncontrolled switches, and the third valve V71 and the fourth valve V72 operate in an uncontrolled state.
  • the third valve V71 and the fourth valve V72 use half-controlled switches to control the third valve and the fourth valve to operate in a locked state.
  • the first converter and the second converter can operate independently or in parallel.
  • control method also includes the following S131.
  • the no-load pressurized state of the second converter 2 is that the second converter 2 is in a direct state.
  • the voltage is adjusted by controlling the firing angle and supplies power to the drive circuit of the fifth valve V73 to achieve high-potential energy harvesting.
  • the fifth valve V73 is also connected in parallel with the second half-control valve, when the fifth valve V73 has over-pressure, over-current or failure, the second half-control valve is controlled to conduct.
  • the first half-control valve and the first full-control valve that control the commutation bridge arm are turned on.
  • control method also includes the following S132.
  • DC power is input from DC buses P1 and N1, and the sixth valve V74 and the seventh valve V75 are controlled to conduct, so that the first converter 1 and the second converter 2 share the DC bus P1, unlocking the The second converter 2 enables the second converter 2 to operate in an inverter state.
  • control method when a fault occurs that may cause commutation failure of the commutation bridge arm of the first converter, the control method also includes the following process.
  • the second valve, the third valve, and the fourth valve include at least one of a half-control switch, a one-way full control switch, a two-way full control switch, and an MMC single valve
  • the corresponding bridge arm of the second inverter is controlled.
  • the third valve or the fourth valve is turned on, and the corresponding bridge arm of the second converter is the bridge arm connected to the same polarity DC bus and the same phase as the commutation bridge arm of the first converter; when the double converter
  • the parallel circuit also includes a fifth valve, and the fifth valve includes at least one of a half-control switch, a one-way full control switch, a two-way full control switch, and an MMC single valve to control the conduction of the fifth valve.
  • controlling the conduction of the corresponding bridge arm of the second converter and the third valve or the fourth valve is to apply a trigger pulse to the corresponding bridge arm of the second converter and the third valve or the fourth valve.
  • the corresponding bridge arm of the second converter and the third valve or the fourth valve In order for the corresponding bridge arm of the second converter and the third valve or the fourth valve to conduct current, the corresponding bridge arm of the second converter and the third valve or the fourth valve must bear the forward voltage to conduct the current.
  • the above-mentioned commutation bridge arm is the bridge arm that commutates to the other bridge arm during normal operation.
  • the corresponding upper arm of the second converter and the third valve are controlled to conduct.
  • the corresponding lower arm of the second converter and the fourth valve are controlled to conduct.
  • the first lower bridge arm of phase A when the first lower bridge arm of phase A commutates to the first lower bridge arm of phase B, at this time, if a fault occurs, it may cause the first lower bridge arm of phase A of the first converter to When the bridge arm commutation fails, the second lower bridge arm of phase A and the fourth valve V72 of the second converter are controlled to conduct.
  • the above-mentioned faults include AC system faults or DC system faults connected by double converters in parallel circuits.
  • AC system faults can be caused by an increase in the zero-sequence component of the AC voltage, a sudden change in the AC voltage, a drop in the AC voltage amplitude, an increase in the harmonics of the AC voltage, or a DC system fault.
  • the fault of the DC system can be judged based on the drop of DC voltage and the increase of DC current, but it is not limited to this.
  • the commutation failure of the commutation bridge arm of the first converter that may be caused by the above is determined based on the turn-off time of the first half-controlled valve of the commutation bridge arm, the valve-side AC current and the AC voltage.
  • the double converter parallel circuit also includes a fifth valve, as shown in Figure 11, Figure 12, Figure 13 and Figure 14, S140
  • the following process S141 is also included.
  • the first full control valve that controls the commutation bridge arm is turned off, so that the current of the commutation bridge arm is transferred to the corresponding bridge arm of the second converter and the third valve or the fourth valve.
  • the corresponding bridge arm of the second converter and the third valve or the fourth valve can withstand the forward voltage that makes the valve conductive.
  • the corresponding bridge arm of the converter and the third valve or the fourth valve conduct current.
  • the first full control valve of the first converter When a fault occurs, the first full control valve of the first converter is turned off before the first half control valve is turned off. As shown in Figures 9, 10, 11, 12, 13, 14 and 15, taking the A-phase first upper bridge arm as an example, the A-phase first upper bridge arm of the first converter 1 is controlled.
  • the first full control valve V42 of Taking arm as an example, the first full control valve V12 that controls the first lower arm of phase A of the first converter 1 is turned off, so that the current of the first lower arm of phase A is transferred to the phase A of the second converter 2
  • the second lower bridge arm V13 and the fourth valve V72 The second lower bridge arm V13 and the fourth valve V72.
  • the second valve, the third valve, and the fourth valve include at least one of a one-way full control switch, a two-way full control switch, and an MMC single valve, Control the corresponding bridge arm of the second converter corresponding to the commutation bridge arm, the third valve or the fourth valve to be turned off. If the second valve, the third valve and the fourth valve only include at least uncontrolled switches and semi-controlled switches.
  • the double converter parallel circuit also includes a fifth valve and the fifth valve includes at least one of a one-way full control switch, a two-way full control switch, and an MMC single valve
  • the fifth valve is controlled to close The current is transferred from the phase where the commutation bridge arm is located to another phase.
  • the second converter and the connecting circuit are controlled to be turned on, and the current is transferred to the second converter and the connecting circuit connected in series with the fully controlled device.
  • the controllable commutation of the first converter based on the half-control device is realized, which effectively suppresses the occurrence of commutation failure and ensures the reliable operation of the double converter.
  • the first half-controlled valve of the commutation bridge arm is turned off when the forward current of the first half-controlled valve is less than the sustaining current and the forward blocking capability is restored.
  • restoring the forward blocking capability refers to restoring the forward blocking capability after the forward current is less than the holding current and the shutdown time is delayed.
  • the shutdown time is less than 700us, but it is not limited to this.
  • S160 also includes the following process S161.
  • the first upper arm of phase A when the fifth valve V73 is controlled to be turned off, if the fifth valve V73 has overvoltage, overcurrent or failure, the first upper arm of phase A of the first converter 1 is controlled.
  • the first semi-control valve V41 and the first full control valve V42 are connected; taking the first lower bridge arm of phase A as an example, when the fifth valve V73 is controlled to be turned off, if the fifth valve V73 has over-pressure, over-current or failure,
  • the first half-control valve V11 and the first full-control valve V12 that control the first upper arm of the A-phase of the first converter 1 are conductive.
  • S160 also includes the following processes S162 and S163.
  • FIG. 17a shows the single-phase ground fault test results of the double converter parallel circuit shown in Figure 10.
  • UAC_IN_L1, UAC_IN_L2 and UAC_IN_L3 are three-phase AC voltage
  • IVY_L1_SCA, IVY_L2_SCA and IVY_L3_SCA are three-phase valve side AC current
  • UDL_IN is DC voltage
  • IDNC is DC current
  • MAIN_BRANCH_CP1, MAIN_BRANCH_CP2, MAIN_BRANCH_CP3, MAIN_BRANCH_CP4, MAIN_BRANCH_CP5 and MAIN_BRANCH_CP6 are the first full control valves V12, MAIN_BRANCH_CP6 respectively.
  • the pulses of V22, V32, V42, V52 and V62, AUX_BRANCH_CP1 is the pulse of the fourth valve V72 (V721 and V722), and AUX_BRANCH_CP4 is the pulse of the third valve V71 (V711 and V712).
  • the AC voltage UAC_IN_L1 becomes 0.
  • the third valve V71 is controlled to conduct, and accordingly, the first half-controlled valve V71 is controlled to conduct.
  • the full control valve V42, V62 or V22 is turned off, and the current is transferred to the third valve V71 and the second valve V43, V63 or V23.
  • the third valve V71 is controlled to be turned off. ; May occur when detecting the first half control valve V11, V31 or V51
  • the fourth valve V72 is controlled to be turned on.
  • the first full control valve V12, V32 or V52 is controlled to be turned off.
  • the current is transferred to the fourth valve V72 and the second valve V13, V33 or V53.
  • the fourth valve V72 is controlled to be turned off.
  • valve-side AC currents IVY_L1_SCA, IVY_L2_SCA and IVY_L3_SCA can still be commutated successfully, the DC voltage UDL_IN maintains about 50%, and the DC current IDNC can also maintain the pre-fault level fluctuation.
  • Test results show that this topology can achieve self-commutation during a single-phase AC fault, maintain a certain power transmission, and will not cause commutation failure.
  • Figure 17b shows the three-phase ground fault test results of the double converter parallel circuit shown in Figure 10. After a ground fault occurs in the three phases of the AC system, the AC voltages UAC_IN_L1, UAC_IN_L2 and UAC_IN_L3 are all 0.
  • valve side AC currents IVY_L1_SCA, IVY_L2_SCA and IVY_L3_SCA can still be commutated successfully, achieving automatic switching that does not depend on the AC voltage during the fault. commutation and capable of providing controlled short-circuit current.
  • FIG. 18a shows the single-phase ground fault test results of the double converter parallel circuit shown in Figure 12.
  • UAC_IN_L1, UAC_IN_L2 and UAC_IN_L3 are three-phase AC voltage
  • IVY_L1_SCA, IVY_L2_SCA and IVY_L3_SCA are three-phase valve side AC current
  • UDL_IN is DC voltage
  • IDNC is DC current
  • MAIN_BRANCH_CP1, MAIN_BRANCH_CP2, MAIN_BRANCH_CP3, MAIN_BRANCH_CP4, MAIN_BRANCH_CP5 and MAIN_BRANCH_CP6 are the first full control valves V12, MAIN_BRANCH_CP6 respectively.
  • the pulses of V22, V32, V42, V52 and V62, AUX_BRANCH_CP1 is the pulse of the fifth valve V73 (V731 and V732).
  • the AC voltage UAC_IN_L1 becomes 0.
  • the fifth valve V73 is controlled to conduct, and accordingly, the first half-controlled valve V73 is controlled to conduct.
  • the full control valve V42, V62 or V22 is turned off, and the current is transferred to the third valve V71, the fifth valve V73 and the second valve V43, V63 or V23.
  • the third valve is controlled.
  • the fifth valve V73 is turned off; when it is detected that the first half control valve V11, V31 or V51 may fail to commutation, the fifth valve V73 is controlled to be turned on, and accordingly, the first full control valve V12, V32 or V52 is controlled to be turned off. , the current is transferred to the fourth valve V72, the fifth valve V73 and the second valve V13, V33 or V53.
  • the fifth valve V73 is controlled to be turned off.
  • valve-side AC currents IVY_L1_SCA, IVY_L2_SCA and IVY_L3_SCA can still be commutated successfully, the DC voltage UDL_IN maintains about 50%, and the DC current IDNC can also maintain the pre-fault level fluctuation.
  • Test results show that this topology can achieve self-commutation during a single-phase AC fault, maintain a certain power transmission, and will not cause commutation failure.
  • Figure 18b shows the three-phase ground fault test results of the double converter parallel circuit shown in Figure 12. After a ground fault occurs in the three phases of the AC system, the AC voltages UAC_IN_L1, UAC_IN_L2 and UAC_IN_L3 are all 0.
  • valve side AC currents IVY_L1_SCA, IVY_L2_SCA and IVY_L3_SCA can still be commutated successfully, achieving automatic switching that does not depend on the AC voltage during the fault. commutation and capable of providing controlled short-circuit current.
  • the embodiment of the present application also provides a control device 300 for a double-converter parallel circuit as described above.
  • the control device includes a detection unit 310 and a control unit 320 .
  • the detection unit 310 is used to detect operating parameters and faults of the double converter parallel circuit.
  • the control unit 320 controls the first converter to operate in the inverter state based on the operating parameters of the double converter parallel circuit. If the second valve includes a half control switch, a one-way full control switch, a two-way full control switch, and an MMC single valve. At least one of them controls the second converter to operate in an inverter state or a blocking state, if the third valve and the fourth valve include at least one of a half-control switch, a one-way full-control switch, a two-way full-control switch, and an MMC single valve. , controlling the third valve and the fourth valve to operate in a locked state.
  • the commutation arm of the first converter may fail to commutation.
  • the second valve, the third valve and the fourth valve include half-controlled switches , one-way full control switch, two-way full control switch, and at least one MMC single valve.
  • the control unit also controls the second corresponding commutation bridge arm.
  • the corresponding bridge arm of the converter and the third valve or the fourth valve are connected.
  • the parallel circuit of the double converter also includes a fifth valve and the fifth valve includes a half-control switch, a one-way full control switch, and a two-way full control switch.
  • At least one of a switch and an MMC single valve controls the conduction of the fifth valve; controls the first full control valve of the commutation bridge arm to turn off, so that the current of the commutation bridge arm is transferred to the corresponding bridge of the second converter.
  • the second valve, third valve, and fourth valve include one-way full control switch, two-way full control switch, MMC single
  • At least one of the valves controls the switching off of the corresponding bridge arm, the third valve or the fourth valve of the second converter corresponding to the commutation bridge arm, if the second valve, the third valve and the fourth valve only include uncontrolled switches , at least one of half-control switches, when the double converter parallel circuit also includes a fifth valve and the fifth valve includes at least one of a one-way full control switch, a two-way full control switch, and an MMC single valve, control
  • the fifth valve is turned off, realizing the current transfer from the phase where the commutation bridge arm is located to another phase.
  • the corresponding bridge arm of the second converter is connected to the same polarity DC bus as the commutation bridge arm of the first converter. and bridge arms of the same phase.

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Abstract

本申请提供双换流器并联电路及其控制方法和装置、直流输电系统。所述双换流器并联电路包括第一换流器、第二换流器和连接电路，第一换流器包括三个第一上桥臂和三个第一下桥臂，每个第一上桥臂和第一下桥臂均包括串联连接的第一半控阀和第一全控阀；第二换流器包括三个第二上桥臂和三个第二下桥臂，每个第二上桥臂和第二下桥臂均包括第二阀；连接电路包括第三阀和第四阀。

Description

双换流器并联电路及其控制方法和装置、直流输电系统 技术领域
本申请涉及高压直流输电技术领域，具体涉及双换流器并联电路及其控制方法和装置、直流输电系统。
背景技术
高压、特高压直流输电容量大，现有技术采用十二脉动电路结构的电网换相换流器，每个十二脉动电路有两个三相六桥臂电路串联，每个桥臂采用单个大容量晶闸管串联，由于晶闸管不能控制关断，现有的换流器结构存在换相失败问题。同时，大容量晶闸管相比小容量晶闸管并联方案成本高。柔性直流输电和混合直流输电的电压源换流器采用半桥结构或全桥结构的模块化多电平换流器，虽然无换相失败问题，但是IGBT(Insulated Gate Bipolar Transistor，绝缘栅双极型晶体管)器件容量小，成本高、损耗大，且电压源换流器存在振荡风险。现有的高压直流输电、柔性直流输电、混合直流输电技术都存在着一些缺陷。
随着接入的高压、特高压直流输电系统逐渐增多，已在多个区域电网形成了多馈入直流输电系统，当发生多条直流同时换相失败时，可能对该区域交流电网安全运行构成威胁。随着新能源发电占比增高，交流电压支撑能力下降，对直流输电系统的稳定运行和抑制换相失败能力提出更高要求。在现有电网换相换流器基础上增加辅助电路来解决换相失败问题成为近几年直流输电技术研究的重要方向，但是，现有采用辅助电路的换流器拓扑结构复杂、成本高、可靠性低，很难满足工程要求。
发明内容
本申请实施例提供一种双换流器并联电路，包括第一换流器、第二换流器、连接电路，所述第一换流器为三相六桥臂电路，包括三个第一上桥臂和三个第一下桥臂，每个所述第一上桥臂和所述第一下桥臂均包括串联连接的第一半控阀和第一全控阀，所述第一半控阀包括半控开关，所述第一全控阀包括单向全控开关、双向全控开关、MMC单阀的至少一种；所述第二换流器为三相六桥臂电路，包括三个第二上桥臂和三个第二下桥臂，每个所述第二上桥臂和所述第二下桥臂均包括第二阀；所述连接电路包括第三阀和第四阀，所述第二阀、第三阀、第四阀包括不控开关、半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，其中，所述第三阀连接所述第一换流器的直流母线正极或第一上桥臂的第一半控阀的第一分段点和所述第二换流器的直流母线正极，所述第四阀连接所述第一换流器的直流母线负极或第一下桥臂的第一半控阀的第二分段 点和所述第二换流器的直流母线负极；或者所述第三阀连接所述第一换流器的直流母线正极或第一上桥臂的第一半控阀的第一分段点和所述第二换流器的直流母线负极，所述第四阀连接所述第一换流器的直流母线负极或第一下桥臂的第一半控阀的第二分段点和所述第二换流器的直流母线正极。
根据一些实施例，所述第一分段点按照耐压水平将所述第一上桥臂的第一半控阀分为两段，所述第二分段点按照耐压水平将所述第一下桥臂的第一半控阀分为两段，两段的耐压比取值范围为0.2～5之间。
根据一些实施例，当所述第三阀连接所述第一分段点时，每个第一上桥臂的所述第一半控阀的第一分段点分别与一个所述第三阀连接；当所述第四阀连接所述第二分段点时，每个第一下桥臂的所述第一半控阀的第二分段点分别与一个所述第四阀连接。
根据一些实施例，所述第一半控阀、第一全控阀、第二阀、第三阀、第四阀两端分别并联避雷器。
根据一些实施例，所述第一全控阀两端并联第二半控阀，所述第二半控阀包括半控开关。
根据一些实施例，所述连接电路还包括第五阀，或第一电容器和第一电阻器的并联电路，或所述并联电路和所述第五阀串联的电路，连接所述第二换流器的直流母线正极和直流母线负极，所述第一电容器包括串联连接的至少一个电容元件。
根据一些实施例，所述连接电路还包括第六阀和第七阀，所述第六阀连接所述第一换流器的直流母线正极和所述第二换流器的直流母线正极，所述第七阀连接所述第一换流器的直流母线负极和所述第二换流器的直流母线负极；所述第五阀、第六阀、第七阀包括不控开关、半控开关、单向全控开关、双向全控开关、MMC单阀、串联连接的全控开关和快速隔离开关的至少一种，所述第五阀、第六阀、第七阀、第一电容器两端分别并联避雷器或/和第二半控阀。
根据一些实施例，所述连接电路还包括避雷器，或者第二电容器和第二电阻器的并联电路，所述避雷器与所述第三阀或/和所述第四阀串联连接；第二电容器和第二电阻器的并联电路，与所述第三阀或/和所述第四阀串联连接。
根据一些实施例，所述第一换流器和所述第二换流器的交流输出端按相并联连接或通过隔离开关或/和刀闸按相并联连接，并连接到同一台换流变压器，所述第一换流器和所述第二换流器的直流母线输入端通过隔离开关或/和刀闸按正负极并联连接。
本申请实施例还提供一种高压直流输电系统，包括如上所述的双换流器并联电路。
本申请实施例还提供一种所述双换流器并联电路的控制方法，包括：控制所述第一换流器运行在逆变状态；如果所述第二阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第二换流器运行在逆变状态或闭锁状态；如果所述第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第三阀、第四阀运行在闭锁状态；当发生故障可能引起所述第一换流器的换相 桥臂换相失败时，包括：如果所述第二阀、第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制与所述换相桥臂对应的第二换流器的相应桥臂及所述第三阀或所述第四阀导通；当所述双换流器并联电路还包括第五阀且所述第五阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀导通；控制所述换相桥臂的第一全控阀关断，使所述换相桥臂的电流转移到所述第二换流器的相应桥臂及所述第三阀或所述第四阀；所述换相桥臂的第一半控阀关断后，如果所述第二阀、第三阀、第四阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第二换流器的相应桥臂、所述第三阀或所述第四阀关断，如果所述第二阀、第三阀、第四阀只包括不控开关、半控开关的至少一种，当所述双换流器并联电路还包括第五阀且所述第五阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀关断，实现了电流从所述换相桥臂所在相转移到另一相，所述第二换流器的相应桥臂为与所述第一换流器换相桥臂连接相同极性直流母线和相同相的桥臂。
根据一些实施例，当所述双换流器并联电路还包括第六阀、第七阀时，所述控制方法还包括：在控制所述换相桥臂的第一全控阀关断时，闭锁所述第二换流器，控制所述第六阀或所述第七阀关断；所述可能引起所述第一换流器的换相桥臂换相失败的工况消失后，控制所述第六阀或/和所述第七阀导通。
根据一些实施例，当所述双换流器并联电路还包括第五阀时，所述控制方法还包括：控制所述第二换流器运行在整流状态或空载加压状态，为所述第五阀的驱动电路供电；当所述第五阀两端并联第二半控阀，所述第五阀过压、过流或故障时，控制所述第二半控阀导通；当控制所述第五阀关断，所述第五阀过压、过流或故障时，控制所述换相桥臂的第一半控阀和第一全控阀导通。
根据一些实施例，当所述双换流器并联电路还包括第六阀和第七阀时，所述控制方法还包括：控制所述第六阀和所述第七阀导通，使得所述第一换流器和所述第二换流器共用直流母线，使得所述第二换流器运行在逆变状态；当所述第一全控阀、第二阀、第三阀、第四阀、第六阀或第七阀两端并联第二半控阀时，所述第一全控阀、第二阀、第三阀、第四阀、第六阀或第七阀过压、过流或故障时，控制所述第二半控阀导通；当控制所述第二换流器的相应桥臂、第三阀或第四阀、第六阀或第七阀关断，所述第二换流器的相应桥臂、第三阀或第四阀、第六阀或第七阀过压、过流或故障时，控制所述换相桥臂的第一半控阀和第一全控阀导通。
本申请实施例还提供一种如上所述的双换流器并联电路的控制装置，包括检测单元和控制单元，所述检测单元用于检测所述双换流器并联电路的运行参数和故障；所述控制单元基于所述双换流器并联电路的运行参数，控制所述第一换流器运行在逆变状态；如果所述第二阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第二换流器运行在逆变状态或闭锁状态；如果所述第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第三阀、第四阀运行在闭锁状态，当发生故障可能引起所述第一换流器的换相桥臂换相失败时，如果所 述第二阀、第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，所述控制单元还控制与所述换相桥臂对应的第二换流器的相应桥臂及所述第三阀或所述第四阀导通，当所述双换流器并联电路还包括第五阀且所述第五阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀导通；控制所述换相桥臂的第一全控阀关断，使所述换相桥臂的电流转移到所述第二换流器的相应桥臂及所述第三阀或所述第四阀，所述换相桥臂的第一半控阀关断后，如果所述第二阀、第三阀、第四阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第二换流器的相应桥臂、所述第三阀或所述第四阀关断，如果所述第二阀、第三阀、第四阀只包括不控开关、半控开关的至少一种，当所述双换流器并联电路还包括第五阀且所述第五阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀关断，实现了电流从所述换相桥臂所在相转移到另一相，所述第二换流器的相应桥臂为与所述第一换流器换相桥臂连接相同极性直流母线和相同相的桥臂。
本申请实施例提供的技术方案，第二换流器的桥臂电路及连接电路与第一换流器的桥臂电路形成并联电路，利用第一换流器换相的第一全控阀关断来实现电流转移到第二换流器的相应桥臂及连接电路，通过关断第二换流器的相应桥臂或连接电路的全控开关实现了基于半控器件的第一换流器可控换相，有效抑制换相失败发生，同时第一换流器和第二换流器组成的双换流器能够并联运行，提高了双换流器的容量和增加了系统的冗余度。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1是本申请实施例提供的一种双换流器并联电路示意图之一。
图2是本申请实施例提供的一种双换流器并联电路示意图之二。
图3是本申请实施例提供的一种双换流器并联电路示意图之三。
图4是本申请实施例提供的一种双换流器并联电路示意图之四。
图5是本申请实施例提供的一种双换流器并联电路示意图之五。
图6是本申请实施例提供的一种双换流器并联电路示意图之六。
图7a-7k是本申请实施例提供的阀结构示意图。
图8是本申请实施例提供的一种双换流器并联电路示意图之七。
图9是本申请实施例提供的一种双换流器并联电路示意图之八。
图10是本申请实施例提供的一种双换流器并联电路示意图之九。
图11是本申请实施例提供的一种双换流器并联电路示意图之十。
图12是本申请实施例提供的一种双换流器并联电路示意图之十一。
图13是本申请实施例提供的一种双换流器并联电路示意图之十二。
图14是本申请实施例提供的一种双换流器并联电路示意图之十三。
图15是本申请实施例提供的一种双换流器并联电路示意图之十四。
图16是本申请实施例的一种双换流器并联电路的控制方法流程示意图。
图17a是本申请实施例的一种双换流器并联电路的单相接地故障试验结果；图17b是本申请实施例的一种双换流器并联电路的三相接地故障试验结果。
图18a是本申请实施例的另一种双换流器并联电路的单相接地故障试验结果；图18b是本申请实施例的另一种双换流器并联电路的三相接地故障试验结果。
图19是本申请实施例提供的一种双换流器并联电路的控制装置示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
应当理解，本申请的权利要求、说明书及附图中的术语“第一”、“第二”、“第三”、“第四”、“第五”、“第六”、“第七”等用于区别不同对象，而不用于描述特定顺序。本申请的说明书和权利要求书中使用的术语“包括”和“包含”指示所描述特征、整体、步骤、操作、元素和/或组件的存在，但并不排除一个或多个其它特征、整体、步骤、操作、元素、组件和/或其集合的存在或添加。
图1是本申请实施例提供的一种双换流器并联电路示意图之一。如图1所示，双换流器并联电路包括第一换流器1、第二换流器2和连接电路。
第一换流器1包括三相六个桥臂，为三个第一上桥臂和三个第一下桥臂，每个第一上桥臂和第一下桥臂均包括串联连接的第一半控阀和第一全控阀。A相第一上桥臂包括串联连接的第一半控阀V41和第一全控阀V42，B相第一上桥臂包括串联连接的第一半控阀V61和第一全控阀V62，C相第一上桥臂包括串联连接的第一半控阀V21和第一全控阀V22。A相第一下桥臂包括串联连接的第一半控阀V11和第一全控阀V12，B相第一下桥臂包括串联连接的第一半控阀V31和第一全控阀V32，C相第一下桥臂包括串联连接的第一半控阀V51和第一全控阀V52。
第二换流器2包括三相六个桥臂，为三个第二上桥臂和三个第二下桥臂，每个第二上桥臂和第二下桥臂均包括第二阀。A相第二上桥臂包括第二阀V43，B相第二上桥臂包括第二阀V63，C相第二上桥臂包括第二阀V23，A相第二下桥臂包括第二阀V13，B相第二下桥臂包括第二阀V33，C相第二下桥臂包括第二阀V53。
连接电路包括第三阀V71和第四阀V72。第三阀V71连接第一换流器1的直流母线正极P1和第二换流器2的直流母线正极P2，第四阀V72连接第一换流器1的直流母线负极N1和第二换流器2的直流母线负极N2，如图1所示。
根据一些实施例，第三阀V71连接第一换流器1的直流母线正极P1和第二换流器2的直流母线负极N2，第四阀V72连接第一换流器1的直流母线负极N1和第二换流器2的直流母线正极P2，如图2所示。
图3是本申请实施例提供的一种双换流器并联电路示意图之三。如图3所示，双换 流器并联电路包括第一换流器1、第二换流器2和连接电路。
第一换流器1包括三相六个桥臂，为三个第一上桥臂和三个第一下桥臂，每个第一上桥臂和第一下桥臂均包括串联连接的第一半控阀和第一全控阀。A相第一上桥臂包括串联连接的第一半控阀V41和第一全控阀V42，B相第一上桥臂包括串联连接的第一半控阀V61和第一全控阀V62，C相第一上桥臂包括串联连接的第一半控阀V21和第一全控阀V22。A相第一下桥臂包括串联连接的第一半控阀V11和第一全控阀V12，B相第一下桥臂包括串联连接的第一半控阀V31和第一全控阀V32，C相第一下桥臂包括串联连接的第一半控阀V51和第一全控阀V52。
第二换流器2包括三相六个桥臂，为三个第二上桥臂和三个第二下桥臂，每个第二上桥臂和第二下桥臂均包括第二阀。A相第二上桥臂包括第二阀V43，B相第二上桥臂包括第二阀V63，C相第二上桥臂包括第二阀V23，A相第二下桥臂包括第二阀V13，B相第二下桥臂包括第二阀V33，C相第二下桥臂包括第二阀V53。
连接电路包括第三阀V71、V81、V91和第四阀V72、V82、V92。第三阀V71连接第一半控阀V41的第一分段点和第二换流器2的直流母线正极P2。第三阀V81连接第一半控阀V61的第一分段点和第二换流器2的直流母线正极P2。第三阀V91连接第一半控阀V21的第一分段点和第二换流器2的直流母线正极P2。第四阀V72连接第一半控阀V11的第二分段点和第二换流器2的直流母线负极N2。第四阀V82连接第一半控阀V31的第二分段点和第二换流器2的直流母线负极N2。第四阀V92连接第一半控阀V51的第二分段点和第二换流器2的直流母线负极N2。
根据一些实施例，第三阀V71连接第一半控阀V41的第一分段点和第二换流器2的直流母线负极N2，第三阀V81连接第一半控阀V61的第一分段点和第二换流器2的直流母线负极N2，第三阀V91连接第一半控阀V21的第一分段点和第二换流器2的直流母线负极N2，第四阀V72连接第一半控阀V11的第二分段点和第二换流器2的直流母线正极P2，第四阀V82连接第一半控阀V31的第二分段点和第二换流器2的直流母线正极P2，第四阀V92连接第一半控阀V51的第二分段点和第二换流器2的直流母线正极P2，如图4所示。
第二阀、第三阀、第四阀包括不控开关、半控开关、单向全控开关、双向全控开关、MMC(Modular Multilevel Converter，模块化多电平换流器)单阀的至少一种，但并不以此为限。
图5是本申请实施例提供的一种双换流器并联电路示意图之五。如图5所示，双换流器并联电路包括第一换流器1、第二换流器2和连接电路。
第一换流器1包括三相六个桥臂，为三个第一上桥臂和三个第一下桥臂，每个第一上桥臂和第一下桥臂均包括串联连接的第一半控阀和第一全控阀。A相第一上桥臂包括串联连接的第一半控阀V41和第一全控阀V42，B相第一上桥臂包括串联连接的第一半控阀V61和第一全控阀V62，C相第一上桥臂包括串联连接的第一半控阀V21和第一全控阀V22。A相第一下桥臂包括串联连接的第一半控阀V11和第一全控阀V12，B相第一下桥臂包括串联连接的第一半控阀V31和第一全控阀V32，C相第一下桥臂包括串联连接的第一半控阀V51和第一全控阀V52。
第二换流器2包括三相六个桥臂，为三个第二上桥臂和三个第二下桥臂，每个第二上桥臂和第二下桥臂均包括第二阀。A相第二上桥臂包括第二阀V43，B相第二上桥臂包括第二阀V63，C相第二上桥臂包括第二阀V23，A相第二下桥臂包括第二阀V13，B相第二下桥臂包括第二阀V33，C相第二下桥臂包括第二阀V53。
连接电路包括第三阀V71、第四阀V72、第五阀V73。第三阀V71连接第一换流器1的直流母线正极P1和第二换流器2的直流母线负极N2，第四阀V72连接第一换流器1的直流母线负极N1和第二换流器2的直流母线正极P2，第五阀V73连接第二换流器2的直流母线正极P2和直流母线负极N2，如图5所示。
根据一些实施例，连接电路还包括第六阀V74、第七阀V75。第六阀V74连接第一换流器1的直流母线正极P1和第二换流器2的直流母线正极P2，第七阀V75连接第一换流器1的直流母线负极N1和第二换流器2的直流母线负极N2，如图6所示。
根据一些实施例，第五阀V73还可以用第一电容器和第一电阻器的并联电路代替，或者用第一电容器和第一电阻器的并联电路再和第五阀V73的串联电路代替。其中，第一电容器包括串联连接的至少一个电容元件，但并不以此为限。可选地，为了控制第一电容器的充放电时间，还串联电阻、电感元件。
第二阀、第三阀、第四阀、第五阀、第六阀、第七阀包括不控开关、半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，但并不以此为限。
根据一些实施例，所述全控开关包括串联连接的至少一个全控器件，所述全控器件包括IGCT(Integrated Gate Commutated Thyristors,集成门极换流晶闸管)、IGBT、GTO(Gate Turn-Off Thyristor，门极可关断晶闸管)、MOSFET(Metal Oxide Semiconductor Field Effect Transistor，金属-氧化物半导体场效应晶体管)的至少一种；所述半控开关包括串联连接的至少一个半控器件，所述半控器件包括晶闸管；所述不控开关包括串联连接的至少一个不控器件，所述不控器件包括二极管。
根据一些实施例，一种不控开关包括串联连接的二极管3，如图7a所示，不能控制开通和关断，具有单向通流能力和单向阻断电压能力。
根据一些实施例，一种半控开关包括串联连接的晶闸管4，如图7b所示，只控制开通，不能控制关断，具有单向通流能力和双向阻断电压能力。可选地，半控开关由晶闸管4和二极管3串联或并联组成。
根据一些实施例，一种单向全控开关包括串联连接的IGBT模块，IGBT模块包括IGBT5和与之反并联的二极管3，如图7c所示，只单向控制开通和关断，具有双向通流和单向阻断电压能力。
根据一些实施例，一种单向全控开关包括串联连接的IGCT6，如图7d所示，只单向控制开通和关断，具有单向通流和双向阻断电压能力。
根据一些实施例，一种单向全控开关包括串联连接的IGBT模块和二极管3，如图7e所示，只单向控制开通和关断，具有单向通流和双向阻断电压能力。
根据一些实施例，一种单向全控开关包括IGCT6和晶闸管4反并联后串联电路，如图7f所示，双向控制开通和单向控制关断，具有双向通流和双向阻断电压能力。
根据一些实施例，一种双向全控开关包括串联连接的正向IGBT模块和反向IGBT模块，如图7g所示，能双向控制开通和关断，具有双向通流能力和双向阻断电压能力。
根据一些实施例，一种双向全控开关包括正向IGCT6和反向IGCT6并联后的串联电路，如图7h所示，能双向控制开通和关断，具有双向通流能力和双向阻断电压能力。
根据一些实施例，一种MMC单阀包括串联连接的子模块，子模块包括两个IGBT模块和电容7，如图7i所示，两个IGBT模块的连接点作为子模块的正极，其中一个IGBT模块的另一端作为子模块的负极，子模块串联连接，只单向控制开通和关断，具有双向通流能力和单向阻断电压能力。
根据一些实施例，一种MMC单阀包括串联连接的子模块，子模块包括四个IGBT模块和电容7，如图7j所示，IGBT模块两两串联连接后并联连接，与电容7也并联连接，IGBT模块两两串联连接的连接点分别作为子模块的正极、负极，子模块串联连接，能双向控制开通和关断，具有双向通流能力和双向阻断电压能力。
根据一些实施例，第五阀、第六阀、第七阀包括串联连接的全控开关和快速隔离开关，如图7k所示，全控开关和快速隔离开关8串联结构。快速隔离开关8提供足够的耐压水平，减少第五阀、第六阀、第七阀的通态损耗和全控开关的耐压水平。需要指出的是，图7c、图7e、图7g、图7i、图7j和图7k中的IGBT可选用IGCT、GTO、MOSFET。
根据一些实施例，晶闸管4配置相应的触发电路；IGBT5配置相应的驱动电路和缓冲电路；IGCT6配置相应的驱动电路和缓冲电路。缓冲电路至少由电容，或电阻和电容串联电路组成。
根据一些实施例，第一半控阀、第一全控阀、第二阀、第三阀、第四阀、第五阀、第六阀、第七阀、第一电容器两端可以分别并联避雷器或/和第二半控阀。如果第一半控阀分段，在两段的两端可以分别并联避雷器。如果第五阀包括半控开关、全控开关，且二者是串联关系，则半控开关、全控开关分别并联避雷器。
根据一些实施例，第一全控阀两端可以并联第二半控阀。
根据一些实施例，第三阀V71还串联避雷器后再与第一换流器1的直流母线正极P1、第二换流器2的直流母线正极P2或第二换流器2的直流母线负极N2连接，第四阀V72还串联避雷器后再与第一换流器1的直流母线负极N1、第二换流器2的直流母线负极N2或第二换流器2的直流母线正极P2连接。如图8所示，第一换流器1的第一半控阀V11、V21、V31、V41、V51和V61分别并联第一避雷器F11、F21、F31、F41、F51和F61，第一换流器1的第一全控阀V12、V22、V32、V42、V52和V62分别并联第二避雷器F12、F22、F32、F42、F52和F62。第二换流器2的第二阀V13、V23、V33、V43、V53和V63分别并联第三避雷器F13、F23、F33、F43、F53和F63。第三阀V71并联第四避雷器F71，第四阀V72并联第五避雷器F72，第三阀V71串联第六避雷器F76，第四阀V72串联第七避雷器F77。第二避雷器F12、F22、F32、F42、F52和F62的耐压水平高于第六避雷器F76和第七避雷器F77。需要指出的是，第六避雷器F76和第七避雷器F77并不是必须串联。如果第一半控阀分为两段，则第一避雷器也要分为两段，并且分别和第一半控阀两段并联。
根据一些实施例，第三阀V71还串联第二电容器和第二电阻器的并联电路后再与第一换流器1的直流母线正极P1、第二换流器2的直流母线正极P2或第二换流器2的直流母线负极N2连接，第四阀V72还串联第二电容器和第二电阻器的并联电路后再与第一换流器1的直流母线负极N1、第二换流器2的直流母线负极N2或第二换流器2的直流母线正极P2连接。
根据一些实施例，第一换流器1和第二换流器2的交流输出端可按相并联连接，即 A1和A2连接，B1和B2连接，C1和C2连接，并分别连接到同一台换流变压器的三相。
图9是本申请实施例提供的一种双换流器并联电路示意图之八。如图9所示，双换流器并联电路包括第一换流器1、第二换流器2和连接电路。
在图1实施例基础上，根据一些实施例，第一换流器1和第二换流器2的交流输出端按相并联连接，即A1和A2连接，B1和B2连接，C1和C2连接，并连接到同一台换流变压器的三相，如图9所示。
根据一些实施例，第一半控阀V11、V21、V31、V41、V51和V61分别包括半控开关，由晶闸管4串联组成，第一全控阀V12、V22、V32、V42、V52和V62分别包括单向全控开关，由IGBT模块串联组成，第二阀V13、V23、V33、V43、V53和V63分别包括半控开关，由晶闸管4串联组成，第三阀V71包括单向全控开关，由IGBT模块串联组成，第四阀V72包括单向全控开关，由IGBT模块串联组成。
根据一些实施例，第一换流器1的第一半控阀V11、V21、V31、V41、V51和V61分别并联第一避雷器F11、F21、F31、F41、F51和F61，第一换流器1的第一全控阀V12、V22、V32、V42、V52和V62分别并联第二避雷器F12、F22、F32、F42、F52和F62。第二换流器2的第二阀V13、V23、V33、V43、V53和V63分别并联第三避雷器F13、F23、F33、F43、F53和F63。第三阀V71并联第四避雷器F71，第四阀V72并联第五避雷器F72，如图9所示。
图10是本申请实施例提供的一种双换流器并联电路示意图之九。如图10所示，双换流器并联电路包括第一换流器1、第二换流器2和连接电路。
在图1实施例基础上，根据一些实施例，第一换流器1和第二换流器2的交流输出端按相并联连接，即A1和A2连接，B1和B2连接，C1和C2连接，并连接到同一台换流变压器的三相，如图10所示。
根据一些实施例，第一半控阀V11、V21、V31、V41、V51和V61分别包括半控开关，由晶闸管4串联组成，第一全控阀V12、V22、V32、V42、V52和V62分别包括单向全控开关，由IGBT模块串联组成，第二阀V13、V23、V33、V43、V53和V63分别包括不控开关，由二极管3串联组成，第三阀V71包括半控开关V711和单向全控开关V712，半控开关V711由晶闸管4串联组成，单向全控开关V712由IGBT模块串联组成，第四阀V72包括串联连接的半控开关V721和单向全控开关V722，半控开关V721由晶闸管4串联组成，单向全控开关V722由IGBT模块串联组成。需要指出的是，第三阀V71或第四阀V72的半控开关作用为提供正向耐压，可用单向全控开关进行替代，因此，第三阀V71或第四阀V72也可全部由单向全控开关组成。
根据一些实施例，第一换流器1的第一半控阀V11、V21、V31、V41、V51和V61分别并联第一避雷器F11、F21、F31、F41、F51和F61，第一换流器1的第一全控阀V12、V22、V32、V42、V52和V62分别并联第二避雷器F12、F22、F32、F42、F52和F62。第二换流器2的第二阀V13、V23、V33、V43、V53和V63分别并联第三避雷器F13、F23、F33、F43、F53和F63。第三阀V71的半控开关V711并联避雷器F711，单向全控开关V712并联第四避雷器F71，第四阀V72的半控开关V721并联避雷器F721，单向全控开关V722并联第五避雷器F72，如图10所示。
图11是本申请实施例提供的一种双换流器并联电路示意图之十。
如图11所示，与图5实施例相同的是，第三阀V71连接第一换流器1的直流母线 正极P1和第二换流器2的直流母线负极N2，第四阀V72连接第一换流器1的直流母线负极N1和第二换流器2的直流母线正极P2。第五阀V73连接第二换流器2的直流母线正极P2和直流母线负极N2。
第一半控阀V11、V21、V31、V41、V51和V61分别包括半控开关，由晶闸管4串联组成，第一全控阀V12、V22、V32、V42、V52和V62分别包括单向全控开关，由IGBT模块串联组成，第二阀V13、V23、V33、V43、V53和V63分别包括半控开关，由晶闸管4串联组成，第三阀V71包括不控开关，由二极管3串联组成，第四阀V72包括不控开关，由二极管3串联组成，第五阀V73包括单向全控开关，由IGBT模块串联组成。
在图5实施例基础上，第一换流器1的第一半控阀V11、V21、V31、V41、V51和V61分别并联第一避雷器F11、F21、F31、F41、F51和F61，第一换流器1的第一全控阀V12、V22、V32、V42、V52和V62分别并联第二避雷器F12、F22、F32、F42、F52和F62。第二换流器2的第二阀V13、V23、V33、V43、V53和V63分别并联第三避雷器F13、F23、F33、F43、F53和F63。第三阀V71并联第四避雷器F71，第四阀V72并联第五避雷器F72，第五阀V73并联第八避雷器F73。
第一换流器1和第二换流器2的交流输出端按相并联连接，即A1和A2连接，B1和B2连接，C1和C2连接，并连接到同一台换流变压器的三相。
图12是本申请实施例提供的一种双换流器并联电路示意图之十一。
如图12所示，与图5实施例相同的是，第三阀V71连接第一换流器1的直流母线正极P1和第二换流器2的直流母线负极N2，第四阀V72连接第一换流器1的直流母线负极N1和第二换流器2的直流母线正极P2。第五阀V73连接第二换流器2的直流母线正极P2和直流母线负极N2。
第一半控阀V11、V21、V31、V41、V51和V61分别包括半控开关，由晶闸管4串联组成，第一全控阀V12、V22、V32、V42、V52和V62分别包括单向全控开关，由IGBT模块串联组成，第二阀V13、V23、V33、V43、V53和V63分别包括不控开关，由二极管3串联组成，第三阀V71包括不控开关，由二极管3串联组成，第四阀V72包括不控开关，由二极管3串联组成，第五阀V73包括半控开关V731和单向全控开关V732，半控开关V731由晶闸管4串联组成，单向全控开关V732由IGBT模块串联组成。需要指出的是，第五阀V73也可全部由单向全控开关组成。
在图5实施例基础上，第一换流器1的第一半控阀V11、V21、V31、V41、V51和V61分别并联第一避雷器F11、F21、F31、F41、F51和F61，第一换流器1的第一全控阀V12、V22、V32、V42、V52和V62分别并联第二避雷器F12、F22、F32、F42、F52和F62。第二换流器2的第二阀V13、V23、V33、V43、V53和V63分别并联第三避雷器F13、F23、F33、F43、F53和F63。第三阀V71并联第四避雷器F71，第四阀V72并联第五避雷器F72，第五阀V73的半控开关V731并联避雷器F731，第五阀V73的单向全控开关V732并联第八避雷器F73。
第一换流器1和第二换流器2的交流输出端按相并联连接，即A1和A2连接，B1和B2连接，C1和C2连接，并连接到同一台换流变压器的三相。
图13是本申请实施例提供的一种双换流器并联电路示意图之十二。
如图13所示，与图11实施例相同的是，第三阀V71连接第一换流器1的直流母线正极P1和第二换流器2的直流母线负极N2，第四阀V72连接第一换流器1的直流母线负极N1和第二换流器2的直流母线正极P2。第五阀V73连接第二换流器2的直流母线正极P2和直流母线负极N2。
在图11实施例基础上，第一全控阀V12、V22、V32、V42、V52和V62两端分别并联第二半控阀V14、V24、V34、V44、V54和V64。第一半控阀V11、V21、V31、V41、V51和V61分别包括半控开关，由晶闸管4串联组成，第一全控阀V12、V22、V32、V42、V52和V62分别包括单向全控开关，由IGBT模块串联组成，第二阀V13、V23、V33、V43、V53和V63分别包括半控开关，由晶闸管4串联组成，第三阀V71包括半控开关，由晶闸管4串联组成，第四阀V72包括半控开关，由晶闸管4串联组成，第五阀V73包括单向全控开关，由IGBT模块串联组成，第二半控阀V14、V24、V34、V44、V54和V64分别包括半控开关，由晶闸管4串联组成。
根据一些实施例，第二阀还可以包括不控开关，由二极管3串联组成。
图14是本申请实施例提供的一种双换流器并联电路示意图之十三。
如图14所示，与图6实施例相同的是，第三阀V71连接第一换流器1的直流母线正极P1和第二换流器2的直流母线负极N2，第四阀V72连接第一换流器1的直流母线负极N1和第二换流器2的直流母线正极P2。第五阀V73连接第二换流器2的直流母线正极P2和直流母线负极N2。第六阀V74连接第一换流器1的直流母线正极P1和第二换流器2的直流母线正极P2，第七阀V75连接第一换流器1的直流母线负极N1和第二换流器2的直流母线负极N2。
在图6实施例基础上，第五阀V73并联第八避雷器F73，第六阀V74并联第九避雷器F74，第七阀V75并联第十避雷器F75。第一换流器1和第二换流器2的交流输出端通过隔离开关或/和刀闸S13、S14、S15、S23、S24和S25按相并联连接,并连接到同一台换流变压器的三相。第一换流器1的直流母线输入端通过隔离开关或/和刀闸S10和S20和第二换流器2的直流母线输入端通过隔离开关或/和刀闸S12和S21按正负极并联连接。第一半控阀V11、V21、V31、V41、V51和V61分别包括半控开关，由晶闸管4串联组成，第一全控阀V12、V22、V32、V42、V52和V62分别包括单向全控开关，由IGBT模块串联组成，第二阀V13、V23、V33、V43、V53和V63分别包括半控开关，由晶闸管4串联组成，第三阀V71包括半控开关，由晶闸管4串联组成，第四阀V72包括半控开关，由晶闸管4串联组成，第五阀V73包括单向全控开关，由IGBT模块串联组成，第六阀V74包括单向全控开关，由IGBT模块串联组成，第七阀V75包括单向全控开关，由IGBT模块串联组成。
当第一换流器1需要检修时，控制隔离开关或/和刀闸S13、S14、S15、S10和S20分开，隔离第一换流器1；当第二换流器2需要检修时，控制隔离开关或/和刀闸S23、S24、S25、S12和S21分开，隔离第二换流器2。
图15是本申请实施例提供的一种双换流器并联电路示意图之十四。
如图15所示，与图5实施例相同的是，第三阀V71连接第一换流器1的直流母线正极P1和第二换流器2的直流母线负极N2，第四阀V72连接第一换流器1的直流母线负极N1和第二换流器2的直流母线正极P2。
如图15所示，在图5实施例基础上，第五阀被第一电容器C11和第一电阻器R11的并联电路代替。
第一电容器C11和第一电阻器R11的并联电路串联连接第二换流器2的直流母线正极P2和直流母线负极N2。第一电容器C11并联第十一避雷器F78。第一换流器1和第二换流器2的交流输出端按相并联连接，即A1和A2连接，B1和B2连接，C1和C2连接，并分别连接到同一台换流变压器的三相。第一半控阀V11、V21、V31、V41、V51和V61分别包括半控开关，由晶闸管4串联组成，第一全控阀V12、V22、V32、V42、V52和V62分别包括单向全控开关，由IGBT模块串联组成，第二阀V13、V23、V33、V43、V53和V63分别包括半控开关，由晶闸管4串联组成，第三阀V71包括单向全控开关，由IGCT6和晶闸管4并联后再串联组成，第四阀V72包括单向全控开关，由IGCT6和晶闸管4并联后再串联组成，第一电容器C11由电容元件串联组成。
本申请实施例还提供一种高压直流输电系统，高压直流输电系统包括如上所述的双换流器并联电路。
图16是本申请实施例提供的一种双换流器并联电路的控制方法流程示意图，包括以下流程。
在S110中，控制第一换流器运行在逆变状态。
在逆变状态中，第一换流器的第一全控阀在第一半控阀关断后再关断。如图9、图10、图11、图12、图13、图14和图15所示，以A相第一上桥臂为例，第一换流器1的第一全控阀V42在第一半控阀V41关断后再关断。
如果第一全控阀还并联第二半控阀，当第一全控阀过压、过流或故障时，控制第二半控阀导通。如图13所示，以A相第一上桥臂为例，当第一全控阀V42过压、过流或故障时，控制第二半控阀V44导通。
在S120中，如果第二阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制第二换流器运行在逆变状态或闭锁状态。
如图9、图11、图13、图14和图15所示，第二阀包括半控开关，当第二换流器的直流侧有电源，交流输出端通过换流变压器连接交流系统时，第二换流器运行在逆变状态；否则，第二换流器运行在闭锁状态。如图10和图12所示，第二换流器运行在不控状态。
在S130中，如果所述第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制第三阀、第四阀运行在闭锁状态。
需要指出的是，只有双换流器并联电路还包括第五阀时，且第五阀为单向全控开关、双向全控开关或MMC单阀时，第三阀、第四阀才选用不控开关或半控开关，当第三阀、第四阀为不控开关时，第三阀、第四阀运行在不控状态。
如图9、图10和图15所示，第三阀V71、第四阀V72至少包括全控开关，控制第三阀、第四阀运行在闭锁状态。如图11和图12所示，第三阀V71、第四阀V72选用不控开关，第三阀V71、第四阀V72运行在不控状态。如图13和图14所示，第三阀V71、第四阀V72选用半控开关，控制第三阀、第四阀运行在闭锁状态。
在本实施例中，第一换流器、第二换流器可独立运行，也可并联运行。
当双换流器并联电路还包括第五阀时，如图11、图13和图14所示，控制方法还包括以下S131。
S131，控制第二换流器运行在整流状态或空载加压状态，为第五阀的驱动电路供电。
如图11、图13和图14所示，第二换流器2的空载加压状态为第二换流器2在直 流侧开路情况下通过控制触发角来实现电压调节并为第五阀V73的驱动电路供电，实现高电位取能。
如果第五阀V73还并联第二半控阀，当第五阀V73过压、过流或故障时，控制第二半控阀导通。
当控制第五阀关断，第五阀过压、过流或故障时，控制换相桥臂的第一半控阀和第一全控阀导通。
当双换流器并联电路还包括第六阀和第七阀时，如图14所示，控制方法还包括以下S132。
S132，控制第六阀和第七阀导通，使得第一换流器和第二换流器共用直流母线，解锁第二换流器，使得第二换流器运行在逆变状态。
如图14所示，直流电源从直流母线P1和N1输入，控制第六阀V74和第七阀V75导通，使得第一换流器1和第二换流器2共用直流母线P1，解锁第二换流器2，使得第二换流器2运行在逆变状态。
如图16所示，当发生故障可能引起第一换流器的换相桥臂换相失败时，控制方法还包括以下流程。
在S140中，如果第二阀、第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制第二换流器的相应桥臂及第三阀或第四阀导通，第二换流器的相应桥臂为与第一换流器的换相桥臂连接相同极性直流母线和相同相的桥臂；当双换流器并联电路还包括第五阀且第五阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制第五阀导通。
需要指出的是，控制第二换流器的相应桥臂及第三阀或第四阀导通，为在第二换流器的相应桥臂及第三阀或第四阀施加触发脉冲，第二换流器的相应桥臂及第三阀或第四阀导通有电流还需要第二换流器的相应桥臂及第三阀或第四阀承受使其导通的正向电压。上述换相桥臂为正常运行时向另一桥臂换相的桥臂。
当发生故障可能引起第一换流器的第一上桥臂换相失败时，控制第二换流器的相应上桥臂及第三阀导通。当发生故障可能引起第一换流器的第一下桥臂换相失败时，控制第二换流器的相应下桥臂及第四阀导通。
如图9、图10和图15所示，以A相第一上桥臂为例，当A相第一上桥臂向B相第一上桥臂换相时，此时，如果发生故障可能引起第一换流器的A相第一上桥臂换相失败时，控制第二换流器的A相第二上桥臂及第三阀V71导通。以A相第一下桥臂为例，当A相第一下桥臂向B相第一下桥臂换相时，此时，如果发生故障可能引起第一换流器的A相第一下桥臂换相失败时，控制第二换流器的A相第二下桥臂及第四阀V72导通。
上述故障包括双换流器并联电路连接的交流系统故障或直流系统故障，交流系统故障可根据交流电压零序分量增大、交流电压突变、交流电压幅值跌落、交流电压谐波增大、直流电流增大进行判断，直流系统故障可根据直流电压跌落、直流电流增大进行判断，但不以此为限。上述可能引起第一换流器的换相桥臂换相失败根据换相桥臂的第一半控阀的关断时刻、阀侧交流电流和交流电压确定，如果换相桥臂的第一半控阀在正常交流电压下的关断时刻还没有关断，则判断为可能引起第一换流器的换相桥臂换相失败，但不以此为限。
当双换流器并联电路还包括第五阀时，如图11、图12、图13和图14所示，S140 还包括以下流程S141。
S141，在控制第二换流器的相应桥臂及第三阀或第四阀导通的同时，控制第五阀导通。
如图11、图12、图13和图14所示，以A相第一上桥臂为例，当A相第一上桥臂向B相第一上桥臂换相时，此时，如果发生故障可能引起第一换流器的A相第一上桥臂换相失败时，控制第二换流器的A相第二上桥臂及第三阀V71、第五阀V73导通；以A相第一下桥臂为例，当A相第一下桥臂向B相第一下桥臂换相时，此时，如果发生故障可能引起第一换流器的A相第一下桥臂换相失败时，控制第二换流器的A相第二下桥臂及第四阀V72、第五阀V73导通。
在S150中，控制换相桥臂的第一全控阀关断，使换相桥臂的电流转移到第二换流器的相应桥臂及第三阀或第四阀。
需要指出的是，控制换相桥臂的第一全控阀关断后，第二换流器的相应桥臂及第三阀或第四阀才承受使阀导通的正向电压，第二换流器的相应桥臂及第三阀或第四阀导通有电流。
在发生故障时，第一换流器的第一全控阀在第一半控阀关断前先关断。如图9、图10、图11、图12、图13、图14和图15所示，以A相第一上桥臂为例，控制第一换流器1的A相第一上桥臂的第一全控阀V42关断，使A相第一上桥臂的电流转移到第二换流器2的A相第二上桥臂V43及第三阀V71；以A相第一下桥臂为例，控制第一换流器1的A相第一下桥臂的第一全控阀V12关断，使A相第一下桥臂的电流转移到第二换流器2的A相第二下桥臂V13及第四阀V72。
在S160中，换相桥臂的第一半控阀关断后，如果第二阀、第三阀、第四阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制换相桥臂对应的第二换流器的相应桥臂、第三阀或第四阀关断，如果第二阀、第三阀、第四阀只包括不控开关、半控开关的至少一种，当所述双换流器并联电路还包括第五阀且所述第五阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀关断，实现了电流从换相桥臂所在相转移到另一相。
如图9、图10和图15所示，以A相第一上桥臂为例，第一半控阀V41关断后，控制第三阀V71关断，强迫电流从A相换为B相，相应地，第三避雷器F71动作吸收第三阀V71的关断能量；以A相第一下桥臂为例，第一半控阀V11关断后，控制第四阀V72关断，强迫电流从A相换为B相，相应地，第四避雷器F72动作吸收第四阀V72的关断能量。图15中，第一电容器C11在此过程中吸收的电量通过第一电阻器R11释放。
如图9、图10和图15所示，以A相第一上桥臂为例，控制第三阀V71关断时，如果第三阀V71过压、过流或故障时，控制第一换流器的第一上桥臂的第一半控阀V41和第一全控阀V42导通；以A相第一下桥臂为例，控制第四阀V72关断时，如果第四阀V72过压、过流或故障时，控制第一换流器的第一上桥臂的第一半控阀V11和第一全控阀V12导通。
在本实施例中，第一换流器因故障可能发生换相失败时，控制第二换流器及连接电路导通，将电流转移到串联全控器件的第二换流器及连接电路中，通过控制全控器件关断实现基于半控器件的第一换流器可控换相，有效抑制换相失败发生，保证了双换流器可靠运行。
上述换相桥臂的第一半控阀关断为上述第一半控阀正向电流小于维持电流并恢复正向阻断能力。具体而言，恢复正向阻断能力是指在正向电流小于维持电流且延时关断时间后恢复正向阻断能力，关断时间小于700us，但并不以此为限。
当双换流器并联电路还包括第五阀时，如图11、图12、图13和图14所示，S160还包括以下流程S161。
S161，换相桥臂的第一半控阀关断后，控制第五阀关断来控制第二换流器的相应桥臂及第三阀或第四阀关断。
如图11、图12、图13和图14所示，以A相第一上桥臂为例，第一半控阀V41关断后，控制第五阀V73关断，强迫电流从A相换为B相，相应地，第八避雷器F73动作吸收第五阀V73的关断能量；以A相第一下桥臂为例，第一半控阀V11关断后，控制第五阀V73关断，强迫电流从A相换为B相，相应地，第八避雷器F73动作吸收第五阀V73的关断能量。以A相第一上桥臂为例，控制第五阀V73关断时，如果第五阀V73过压、过流或故障时，控制第一换流器1的A相第一上桥臂的第一半控阀V41和第一全控阀V42导通；以A相第一下桥臂为例，控制第五阀V73关断时，如果第五阀V73过压、过流或故障时，控制第一换流器1的A相第一上桥臂的第一半控阀V11和第一全控阀V12导通。
当双换流器并联电路还包括第六阀和第七阀时，如图14所示，S160还包括以下流程S162和S163。
S162，在控制换相桥臂的第一全控阀关断时，闭锁第二换流器，控制第六阀或第七阀关断。
如图14所示，以A相第一上桥臂为例，控制A相第一上桥臂的第一全控阀V42关断时，控制第六阀V74关断；以A相第一下桥臂为例，控制A相第一下桥臂的第一全控阀V12关断时，控制第七阀V75关断。
S163，当可能引起所述第一换流器的换相桥臂换相失败的工况消失后，控制第六阀或/和第七阀导通。
如图14所示，当可能引起所述第一换流器的换相桥臂换相失败的工况消失后，控制第六阀V74和第七阀V75导通，解锁第二换流器2，第二换流器2运行在逆变状态，第一换流器1和第二换流器2并联运行。
图17a示出了图10所示双换流器并联电路的单相接地故障试验结果。UAC_IN_L1、UAC_IN_L2和UAC_IN_L3为三相交流电压；IVY_L1_SCA、IVY_L2_SCA和IVY_L3_SCA为三相阀侧交流电流；UDL_IN为直流电压；IDNC为直流电流；CPRY为第一半控阀V11、V21、V31、V41、V51和V61的触发标识，如CPRY＝12，换算成二进制为0x1001，则为第一半控阀V41和V11导通；MAIN_BRANCH_CP1、MAIN_BRANCH_CP2、MAIN_BRANCH_CP3、MAIN_BRANCH_CP4、MAIN_BRANCH_CP5和MAIN_BRANCH_CP6分别为第一全控阀V12、V22、V32、V42、V52和V62的脉冲，AUX_BRANCH_CP1为第四阀V72(V721和V722)的脉冲，AUX_BRANCH_CP4为第三阀V71(V711和V712)的脉冲。交流系统A相发生接地故障后，交流电压UAC_IN_L1变为0，当检测到第一半控阀V41、V61或V21可能发生换相失败时，控制第三阀V71导通，相应地，控制第一全控阀V42、V62或V22关断，电流转移到第三阀V71和第二阀V43、V63或V23，当第一半控阀V41、V61或V21关断后，控制第三阀V71关断；当检测到第一半控阀V11、V31或V51可能发生 换相失败时，控制第四阀V72导通，相应地，控制第一全控阀V12、V32或V52关断，电流转移到第四阀V72和第二阀V13、V33或V53，当第一半控阀V11、V31或V51关断后，控制第四阀V72关断。在整个故障期间，阀侧交流电流IVY_L1_SCA、IVY_L2_SCA和IVY_L3_SCA仍能够换流成功，直流电压UDL_IN维持50％左右，直流电流IDNC也可以维持故障前水平波动。试验结果表明，该拓扑结构在单相交流故障时可实现自换相，维持一定功率输送，不会发生换相失败。图17b示出了图10所示双换流器并联电路的三相接地故障试验结果。交流系统三相发生接地故障后，交流电压UAC_IN_L1、UAC_IN_L2和UAC_IN_L3都为0，在整个故障期间，阀侧交流电流IVY_L1_SCA、IVY_L2_SCA和IVY_L3_SCA仍能够换流成功，实现了故障期间不依赖交流电压的自换相，并能够提供受控的短路电流。
图18a示出了图12所示双换流器并联电路的单相接地故障试验结果。UAC_IN_L1、UAC_IN_L2和UAC_IN_L3为三相交流电压；IVY_L1_SCA、IVY_L2_SCA和IVY_L3_SCA为三相阀侧交流电流；UDL_IN为直流电压；IDNC为直流电流；CPRY为第一半控阀V11、V21、V31、V41、V51和V61的触发标识，如CPRY＝12，换算成二进制为0x1001，则为第一半控阀V41和V11导通；MAIN_BRANCH_CP1、MAIN_BRANCH_CP2、MAIN_BRANCH_CP3、MAIN_BRANCH_CP4、MAIN_BRANCH_CP5和MAIN_BRANCH_CP6分别为第一全控阀V12、V22、V32、V42、V52和V62的脉冲，AUX_BRANCH_CP1为第五阀V73(V731和V732)的脉冲。交流系统A相发生接地故障后，交流电压UAC_IN_L1变为0，当检测到第一半控阀V41、V61或V21可能发生换相失败时，控制第五阀V73导通，相应地，控制第一全控阀V42、V62或V22关断，电流转移到第三阀V71、第五阀V73和第二阀V43、V63或V23，当第一半控阀V41、V61或V21关断后，控制第五阀V73关断；当检测到第一半控阀V11、V31或V51可能发生换相失败时，控制第五阀V73导通，相应地，控制第一全控阀V12、V32或V52关断，电流转移到第四阀V72、第五阀V73和第二阀V13、V33或V53，当第一半控阀V11、V31或V51关断后，控制第五阀V73关断。在整个故障期间，阀侧交流电流IVY_L1_SCA、IVY_L2_SCA和IVY_L3_SCA仍能够换流成功，直流电压UDL_IN维持50％左右，直流电流IDNC也可以维持故障前水平波动。试验结果表明，该拓扑结构在单相交流故障时可实现自换相，维持一定功率输送，不会发生换相失败。图18b示出了图12所示双换流器并联电路的三相接地故障试验结果。交流系统三相发生接地故障后，交流电压UAC_IN_L1、UAC_IN_L2和UAC_IN_L3都为0，在整个故障期间，阀侧交流电流IVY_L1_SCA、IVY_L2_SCA和IVY_L3_SCA仍能够换流成功，实现了故障期间不依赖交流电压的自换相，并能够提供受控的短路电流。
本申请实施例还提供一种如上所述的双换流器并联电路的控制装置300，如图19所示，控制装置包括检测单元310和控制单元320。
检测单元310用于检测双换流器并联电路的运行参数和故障。控制单元320基于双换流器并联电路的运行参数，控制第一换流器运行在逆变状态，如果第二阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制第二换流器运行在逆变状态或闭锁状态，如果第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制第三阀、第四阀运行在闭锁状态，当发生故障可能引起第一换流器的换相桥臂换相失败时，如果第二阀、第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制单元还控制换相桥臂对应的第二 换流器的相应桥臂及第三阀或第四阀导通，当双换流器并联电路还包括第五阀且所述第五阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀导通；控制换相桥臂的第一全控阀关断，使换相桥臂的电流转移到第二换流器的相应桥臂及第三阀或第四阀，换相桥臂的第一半控阀关断后，如果第二阀、第三阀、第四阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制换相桥臂对应的第二换流器的相应桥臂、第三阀或第四阀关断，如果第二阀、第三阀、第四阀只包括不控开关、半控开关的至少一种，当所述双换流器并联电路还包括第五阀且所述第五阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀关断，实现了电流从换相桥臂所在相转移到另一相，第二换流器的相应桥臂为与第一换流器换相桥臂连接相同极性直流母线和相同相的桥臂。
以上实施例仅为说明本申请的技术思想，不能以此限定本申请的保护范围，凡是按照本申请提出的技术思想，在技术方案基础上所做的任何改动，均落入本申请保护范围之内。

Claims (15)

  1. 一种双换流器并联电路，包括：
    第一换流器，为三相六桥臂电路，包括三个第一上桥臂和三个第一下桥臂，每个所述第一上桥臂和所述第一下桥臂均包括串联连接的第一半控阀和第一全控阀，所述第一半控阀包括半控开关，所述第一全控阀包括单向全控开关、双向全控开关、MMC单阀的至少一种；
    第二换流器，为三相六桥臂电路，包括三个第二上桥臂和三个第二下桥臂，每个所述第二上桥臂和所述第二下桥臂均包括第二阀；
    连接电路，包括第三阀和第四阀，所述第二阀、第三阀、第四阀包括不控开关、半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，其中，
    所述第三阀连接所述第一换流器的直流母线正极或第一上桥臂的第一半控阀的第一分段点和所述第二换流器的直流母线正极，所述第四阀连接所述第一换流器的直流母线负极或第一下桥臂的第一半控阀的第二分段点和所述第二换流器的直流母线负极；或者
    所述第三阀连接所述第一换流器的直流母线正极或第一上桥臂的第一半控阀的第一分段点和所述第二换流器的直流母线负极，所述第四阀连接所述第一换流器的直流母线负极或第一下桥臂的第一半控阀的第二分段点和所述第二换流器的直流母线正极。
  2. 如权利要求1所述的双换流器并联电路，其中，所述第一分段点按照耐压水平将所述第一上桥臂的第一半控阀分为两段，所述第二分段点按照耐压水平将所述第一下桥臂的第一半控阀分为两段，两段的耐压比取值范围为0.2～5之间。
  3. 如权利要求1所述的双换流器并联电路，其中，当所述第三阀连接所述第一分段点时，每个第一上桥臂的所述第一半控阀的第一分段点分别与一个所述第三阀连接；当所述第四阀连接所述第二分段点时，每个第一下桥臂的所述第一半控阀的第二分段点分别与一个所述第四阀连接。
  4. 如权利要求1所述的双换流器并联电路，其中，所述第一半控阀、第一全控阀、第二阀、第三阀、第四阀两端分别并联避雷器。
  5. 如权利要求1所述的双换流器并联电路，其中，所述第一全控阀两端并联第二半控阀，所述第二半控阀包括半控开关。
  6. 如权利要求1所述的双换流器并联电路，其中，所述连接电路还包括：
    第五阀，或第一电容器和第一电阻器的并联电路，或所述并联电路和所述第五阀串联的电路，连接所述第二换流器的直流母线正极和直流母线负极，所述第一电容器包括串联连接的至少一个电容元件。
  7. 如权利要求6所述的双换流器并联电路，其中，所述连接电路还包括：
    第六阀，连接所述第一换流器的直流母线正极和所述第二换流器的直流母线正极，
    第七阀，连接所述第一换流器的直流母线负极和所述第二换流器的直流母线负极；
    所述第五阀、第六阀、第七阀包括不控开关、半控开关、单向全控开关、双向全控开关、MMC单阀、串联连接的全控开关和快速隔离开关的至少一种，所述第五阀、第六阀、第七阀、第一电容器两端分别并联避雷器或/和第二半控阀。
  8. 如权利要求1所述的双换流器并联电路，其中，所述连接电路还包括：
    避雷器，与所述第三阀或/和所述第四阀串联连接；或者
    第二电容器和第二电阻器的并联电路，与所述第三阀或/和所述第四阀串联连接。
  9. 如权利要求1所述的双换流器并联电路，其中，所述第一换流器和所述第二换流器的交流输出端按相并联连接或通过隔离开关或/和刀闸按相并联连接，并连接到同一台换流变压器，所述第一换流器和所述第二换流器的直流母线输入端通过隔离开关或/和刀闸按正负极并联连接。
  10. 一种高压直流输电系统，包括所述权利要求1至9之任一项所述的双换流器并联电路。
  11. 一种如权利要求1至9之任一项所述的双换流器并联电路的控制方法，包括：
    控制所述第一换流器运行在逆变状态；
    如果所述第二阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第二换流器运行在逆变状态或闭锁状态；
    如果所述第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第三阀、第四阀运行在闭锁状态；
    当发生故障可能引起所述第一换流器的换相桥臂换相失败时，包括：
    如果所述第二阀、第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制与所述换相桥臂对应的第二换流器的相应桥臂及所述第三阀或所述第四阀导通；当所述双换流器并联电路还包括第五阀且所述第五阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀导通；
    控制所述换相桥臂的第一全控阀关断，使所述换相桥臂的电流转移到所述第二换流器的相应桥臂及所述第三阀或所述第四阀；
    所述换相桥臂的第一半控阀关断后，如果所述第二阀、第三阀、第四阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第二换流器的相应桥臂、所述第三阀或所述第四阀关断，如果所述第二阀、第三阀、第四阀只包括不控开关、半控开关的至少一种，当所述双换流器并联电路还包括第五阀且所述第五阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀关断，实现了电流从所述换相桥臂所在相转移到另一相，所述第二换流器的相应桥臂为与所述第一换流器的换相桥臂连接相同极性直流母线和相同相的桥臂。
  12. 如权利要求11所述的控制方法，其中，当所述双换流器并联电路还包括第六 阀、第七阀时，所述控制方法还包括：
    在控制所述换相桥臂的第一全控阀关断时，闭锁所述第二换流器，控制所述第六阀或所述第七阀关断；
    所述可能引起所述第一换流器的换相桥臂换相失败的工况消失后，控制所述第六阀或/和所述第七阀导通。
  13. 如权利要求11所述的控制方法，当所述双换流器并联电路还包括第五阀时，所述控制方法还包括：
    控制所述第二换流器运行在整流状态或空载加压状态，为所述第五阀的驱动电路供电；
    当所述第五阀两端并联第二半控阀，所述第五阀过压、过流或故障时，控制所述第二半控阀导通；
    当控制所述第五阀关断，所述第五阀过压、过流或故障时，控制所述换相桥臂的第一半控阀和第一全控阀导通。
  14. 如权利要求11所述的控制方法，其中，当所述双换流器并联电路还包括第六阀和第七阀时，所述控制方法还包括：
    控制所述第六阀和所述第七阀导通，使得所述第一换流器和所述第二换流器共用直流母线，使得所述第二换流器运行在逆变状态；
    当所述第一全控阀、第二阀、第三阀、第四阀、第六阀或第七阀两端并联第二半控阀时，所述第一全控阀、第二阀、第三阀、第四阀、第六阀或第七阀过压、过流或故障时，控制所述第二半控阀导通；
    当控制所述第二换流器的相应桥臂、第三阀或第四阀、第六阀或第七阀关断，所述第二换流器的相应桥臂、第三阀或第四阀、第六阀或第七阀过压、过流或故障时，控制所述换相桥臂的第一半控阀和第一全控阀导通。
  15. 一种如权利要求1至9之任一项所述的双换流器并联电路的控制装置，包括：
    检测单元，用于检测所述双换流器并联电路的运行参数和故障；
    控制单元，基于所述双换流器并联电路的运行参数，控制所述第一换流器运行在逆变状态；如果所述第二阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第二换流器运行在逆变状态或闭锁状态；如果所述第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第三阀、第四阀运行在闭锁状态，当发生故障可能引起所述第一换流器的换相桥臂换相失败时，如果所述第二阀、第三阀、第四阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，所述控制单元还控制与所述换相桥臂对应的第二换流器的相应桥臂及所述第三阀或所述第四阀导通，当所述双换流器并联电路还包括第五阀且所述第五阀包括半控开关、单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀导通；控制所述换相桥臂的第一全控阀关断，使所述换相桥臂的电流转移到所述第二换流器的相应桥臂及所述第三阀或所述第四阀，所述换相桥臂的第一半控阀关断 后，如果所述第二阀、第三阀、第四阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第二换流器的相应桥臂、所述第三阀或所述第四阀关断，如果所述第二阀、第三阀、第四阀只包括不控开关、半控开关的至少一种，当所述双换流器并联电路还包括第五阀且所述第五阀包括单向全控开关、双向全控开关、MMC单阀的至少一种，控制所述第五阀关断，实现了电流从所述换相桥臂所在相转移到另一相，所述第二换流器的相应桥臂为与所述第一换流器换相桥臂连接相同极性直流母线和相同相的桥臂。
PCT/CN2023/093459 2022-05-12 2023-05-11 双换流器并联电路及其控制方法和装置、直流输电系统 Ceased WO2023217218A1 (zh)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118249666A (zh) * 2024-03-13 2024-06-25 南京南瑞继保电气有限公司 可控关断电网换相换流器及其控制方法和装置、系统
CN119813329A (zh) * 2024-12-12 2025-04-11 南京南瑞继保电气有限公司 换流阀厅
CN120016860A (zh) * 2024-03-13 2025-05-16 南京南瑞继保电气有限公司 全桥电路关断电网换相换流器及其控制方法和装置、系统
CN121036566A (zh) * 2025-10-31 2025-11-28 北京怀柔实验室 多相级联型模块化换向式换流器、控制方法和输电系统

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118249665A (zh) * 2024-03-13 2024-06-25 南京南瑞继保电气有限公司 电容辅助关断电网换相换流器及其控制方法和装置、系统
CN120016861B (zh) * 2024-03-13 2026-03-20 南京南瑞继保电气有限公司 相单元、主动换相换流器及其控制方法和装置、系统
CN120016859B (zh) * 2024-03-13 2025-12-09 南京南瑞继保电气有限公司 集中式可控关断电网换相换流器、控制方法和装置、系统

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140254228A1 (en) * 2013-03-08 2014-09-11 Delta Electronics, Inc Three-level converter
CN106100404A (zh) * 2016-06-07 2016-11-09 南方电网科学研究院有限责任公司 一种模块化多电平换流器及其使用方法
CN110556802A (zh) * 2019-09-25 2019-12-10 南京南瑞继保电气有限公司 一种多换流器直流输电系统换流器故障保护方法
CN112311272A (zh) * 2019-08-02 2021-02-02 全球能源互联网研究院有限公司 一种直流侧辅助换相的混合式换流器拓扑结构及其控制方法
CN112803799A (zh) * 2021-02-01 2021-05-14 全球能源互联网研究院有限公司 直流侧共母线辅助换相的混合式换流器拓扑结构及其方法
CN112803798A (zh) * 2021-02-01 2021-05-14 全球能源互联网研究院有限公司 主动换相单元、强迫换相的混合式换流器拓扑结构及方法

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107968588B (zh) * 2017-12-17 2019-08-30 华中科技大学 一种级联换流阀、直流输电系统及其控制方法
CN108712090B (zh) * 2018-07-03 2024-04-19 清华大学 一种高压直流输电混合换流器
CN112311274B (zh) * 2019-08-02 2024-05-28 国网智能电网研究院有限公司 一种基于可控关断的混合式换流器拓扑结构及其控制方法
WO2021093746A1 (zh) * 2019-11-11 2021-05-20 南京南瑞继保电气有限公司 混合直流换流器在线退出电路、退出方法及退出装置
CN111600497B (zh) * 2020-04-03 2022-04-29 清华大学 抑制高压直流换相失败的串联双向二极管桥换流器

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140254228A1 (en) * 2013-03-08 2014-09-11 Delta Electronics, Inc Three-level converter
CN106100404A (zh) * 2016-06-07 2016-11-09 南方电网科学研究院有限责任公司 一种模块化多电平换流器及其使用方法
CN112311272A (zh) * 2019-08-02 2021-02-02 全球能源互联网研究院有限公司 一种直流侧辅助换相的混合式换流器拓扑结构及其控制方法
CN110556802A (zh) * 2019-09-25 2019-12-10 南京南瑞继保电气有限公司 一种多换流器直流输电系统换流器故障保护方法
CN112803799A (zh) * 2021-02-01 2021-05-14 全球能源互联网研究院有限公司 直流侧共母线辅助换相的混合式换流器拓扑结构及其方法
CN112803798A (zh) * 2021-02-01 2021-05-14 全球能源互联网研究院有限公司 主动换相单元、强迫换相的混合式换流器拓扑结构及方法

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN118249666A (zh) * 2024-03-13 2024-06-25 南京南瑞继保电气有限公司 可控关断电网换相换流器及其控制方法和装置、系统
CN120016860A (zh) * 2024-03-13 2025-05-16 南京南瑞继保电气有限公司 全桥电路关断电网换相换流器及其控制方法和装置、系统
CN119813329A (zh) * 2024-12-12 2025-04-11 南京南瑞继保电气有限公司 换流阀厅
CN121036566A (zh) * 2025-10-31 2025-11-28 北京怀柔实验室 多相级联型模块化换向式换流器、控制方法和输电系统

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