CN116054585A - Novel high-voltage direct-current transformer and control method - Google Patents

Novel high-voltage direct-current transformer and control method Download PDF

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Publication number
CN116054585A
CN116054585A CN202310021948.4A CN202310021948A CN116054585A CN 116054585 A CN116054585 A CN 116054585A CN 202310021948 A CN202310021948 A CN 202310021948A CN 116054585 A CN116054585 A CN 116054585A
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China
Prior art keywords
voltage
bridge arm
full
power switch
series
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Chinese (zh)
Inventor
曾嵘
张雪垠
赵彪
崔彬
屈鲁
余占清
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Tsinghua University
Sichuan Energy Internet Research Institute EIRI Tsinghua University
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Tsinghua University
Sichuan Energy Internet Research Institute EIRI Tsinghua University
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Priority to CN202310021948.4A priority Critical patent/CN116054585A/en
Publication of CN116054585A publication Critical patent/CN116054585A/en
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    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33569—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having several active switching elements
    • 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
    • H02M1/0067—Converter structures employing plural converter units, other than for parallel operation of the units on a single load
    • H02M1/007—Plural converter units in cascade
    • 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
    • H02M1/096—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 the power supply of the control circuit being connected in parallel to the main switching element
    • 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
    • H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
    • 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]

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention provides a novel high-voltage direct-current transformer, which comprises an isolation transformer and a converter valve, wherein the isolation transformer comprises at least two alternating-current ports, and each alternating-current port is correspondingly connected with one or more converter valves. The invention greatly reduces the consumption of power switch devices and capacitors.

Description

Novel high-voltage direct-current transformer and control method
Technical Field
The invention belongs to the technical field of high-voltage direct-current transmission systems, and particularly relates to a novel high-voltage direct-current transformer and a control method.
Background
With the vigorous development of renewable energy sources, new power systems are receiving attention from academia and industry. The direct current system is a novel power system which is in sharp contrast with the alternating current system. Compared with an alternating current system, the direct current system has the advantages of stability, high efficiency, strong controllability, low harmonic level and the like, and is an ideal mode for collecting and conveying renewable energy sources.
Unlike alternating current, direct current cannot realize voltage variation through electromagnetic induction principle, and thus, a direct current transformer based on power electronics technology is a core device of a direct current system. Dc systems often require multiple voltage conversion, wherein a dc transformer that converts high voltage dc into medium voltage or low voltage dc, often referred to as a high voltage dc transformer. The existing high-voltage direct-current transformer has fewer topology types, generally has the problems of large consumption of power switching devices (full-control devices and diodes) and capacitors, and has no soft switching characteristic of the power switching devices. The problems of high cost, large volume, low efficiency and poor reliability of the existing scheme seriously restrict the development of a direct current system.
Therefore, a novel high-voltage direct-current transformer and a control method are needed to solve the above technical problems.
Disclosure of Invention
Aiming at the technical problems, the invention provides a novel high-voltage direct-current transformer, which comprises an isolation transformer and a converter valve, wherein,
the isolation transformer comprises at least two alternating current ports, and each alternating current port is correspondingly connected with one or more converter valves.
Further, at least one of the at least two alternating current ports is a novel converter valve.
Further, the novel converter valve comprises a smoothing reactor, one or a plurality of switch capacitor valve groups connected in parallel and one or a plurality of novel series valve groups connected in parallel, wherein,
the switch capacitor valve bank is connected with the novel series valve bank in parallel, and the smoothing reactance is connected with the switch capacitor valve bank and the novel series valve bank in series in parallel.
Further, the novel serial valve bank comprises two upper bridge arms and two lower bridge arms, wherein one end of one upper bridge arm is connected with one end of one lower bridge arm through a connecting midpoint, and one end of the other upper bridge arm is connected with one end of the other lower bridge arm through the other connecting midpoint; the other end of one of the upper bridge arms is connected with the other end of the other upper bridge arm, the other end of one of the lower bridge arms is connected with the other end of the other lower bridge arm, wherein,
The upper bridge arm and the lower bridge arm comprise one or a plurality of first power switch modules connected in series.
Further, the first power switch module comprises a full control device T1, a diode D1, a voltage equalizing capacitor C1 and energy dissipation elements, wherein,
the anode of the diode D1 is connected with the anode of the full-control device T1, one end of the voltage-sharing capacitor C1 is connected with the cathode of the diode D1, the other end of the voltage-sharing capacitor C1 is connected with the cathode of the full-control device T1, one end of the energy-consuming element is connected with one end of the voltage-sharing capacitor C1, and the other end of the energy-consuming element is connected with the other end of the voltage-sharing capacitor C1.
Further, when the upper bridge arm and the lower bridge arm each include a first power switch module:
in the upper bridge arm, an anode of a full-control device T1 in the first power switch module is used as the other end of the upper bridge arm, and a cathode of the full-control device T1 in the first power switch module is used as one end of the upper bridge arm;
in the lower bridge arm, an anode of a full-control device T1 in the first power switch module is used as one end of the lower bridge arm, and a cathode of the full-control device T1 in the first power switch module is used as the other end of the lower bridge arm.
Further, when the upper bridge arm and the lower bridge arm each include a plurality of first power switch modules connected in series:
In the upper bridge arm, a plurality of full control devices T1 are connected in series, the anode of a first full control device T1 in a first power switch module is used as the other end of the upper bridge arm, and the cathode of the full control device T1 in the last first power switch module is used as one end of the upper bridge arm;
in the lower bridge arm, a plurality of full-control devices T1 are connected in series, the anode of a first full-control device T1 in a first power switch module is used as one end of the lower bridge arm, and the cathode of the full-control device T1 in a last power switch module is used as the other end of the lower bridge arm.
Further, one end of the switch capacitor valve bank is connected with the other end of the upper bridge arm, and the other end of the switch capacitor valve bank is connected with the other end of the lower bridge arm.
Further, the switched capacitor valve bank comprises one or more second power switch modules connected in series, wherein,
when the switched capacitor valve bank comprises a second power switch module:
one end of the second power switch module is used as one end of the switch capacitor valve bank, and the other end of the second power switch module is used as the other end of the switch capacitor valve bank;
when the switched capacitor valve bank comprises a plurality of second power switch modules connected in series:
One end of the first second power switch module is used as one end of the switch capacitor valve group, and the other end of the last second power switch module is used as the other end of the switch capacitor valve group;
the second power switch module is any one of a half-bridge circuit, a full-bridge circuit and a hybrid module.
Further, the switched capacitor valve block includes a hybrid module including a first number of half-bridge circuits in series and a second number of full-bridge circuits in series, wherein,
the first number of half-bridge circuits in series is in series with the second number of full-bridge circuits in series.
Further, the energy consumption element is any one or combination of an energy taking power supply, a first energy consumption resistor and a switchable energy consumption resistor,
the energy-taking power supply is used for obtaining energy from the voltage-sharing capacitor and supplying power to the control circuit of the first power switch module.
On the other hand, the invention also provides a control method of the novel high-voltage direct-current transformer, wherein the control method of the direct-current transformer comprises the following steps:
the output voltage of the switch capacitor valve bank is controlled to be t before the on-off state of the novel series valve bank is switched cq The time is reduced to 0, and the novel series valve group soft switch is realized.
The invention provides a novel high-voltage direct-current transformer and a control method thereof, which greatly reduce the consumption of power switching devices and capacitors, and the direct-current transformer topology provided by the invention can realize zero-voltage conduction (ZVS, zeroVoltageSwitch) and quasi-zero-current turn-off (ZCS, zeroCurrentSwitch) of the power switching devices, so that the cost is low, the efficiency is high, and the volume is small. The fewer components also make the topology reliability of the DC transformer higher than that of the traditional topology.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the following will be described
The drawings that are needed in the description of the embodiments and prior art are briefly introduced, and it is apparent 5 that the drawings in the following description are some embodiments of the present invention, for one of ordinary skill in the art
Other figures can be obtained from these figures without the inventive effort.
Fig. 1 shows a topology diagram of a novel high voltage dc transformer according to an embodiment of the present invention.
Fig. 2 shows a topology of the energy consuming element 0 when the energy consuming element is an energy taking power supply according to an embodiment of the present invention.
Fig. 3 shows a topology of the dissipative element when the dissipative element is the first dissipative resistor according to an embodiment of the invention.
Fig. 4 shows a topology of the energy dissipating element when the energy dissipating element is a switchable energy dissipating resistor according to an embodiment of the present invention.
Fig. 5 shows a topology of a combination of one according to an embodiment of the invention.
Fig. 6 shows a topology of a combination two according to an embodiment of the invention.
Fig. 7 shows a topology of a combination form three according to an embodiment of the present invention.
Fig. 8 shows a topology of a switched capacitor valve bank when the second power switch module is a half-bridge circuit according to an embodiment of the invention.
Figure 9 illustrates when the second power switch module is a full bridge circuit according to an embodiment of the invention,
topology of switched capacitor valve bank.
Fig. 10 shows a topology of a hybrid module according to an embodiment of the invention.
Fig. 11 shows a topology of a modular multilevel converter MMC according to an embodiment of the invention.
Fig. 12 shows a topology of a first device tandem H-bridge structure according to an embodiment of the invention.
Fig. 13 shows a topology of a second device tandem H-bridge structure according to an embodiment of the invention.
Fig. 14 shows a flowchart of a control method of a novel high voltage dc transformer according to an embodiment of the present invention.
Fig. 15 shows a topology of a novel high voltage dc transformer in a case according to an embodiment of the present invention.
Fig. 16 shows graphs of high side AC port voltage, low side AC port voltage, high side new series valve stack modulation wave voltage, high side switched capacitor valve stack voltage, low side new series valve stack modulation wave voltage, and low side switched capacitor valve stack voltage over time t according to an embodiment of the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
As shown in fig. 1, the present invention provides a novel high voltage dc transformer comprising an isolation transformer and a converter valve, wherein,
the isolation transformer comprises at least two alternating current ports, and each alternating current port is correspondingly connected with one or more converter valves.
A novel high voltage dc transformer topology of the present invention is described in detail below.
In one embodiment of the invention, each AC port (AC port, e.g., AC port 1, AC port 2..ac port N) in the isolation transformer has an ac+ end and an AC-end, wherein the isolation transformer may or may not employ a ferromagnetic transformer, i.e., the ac+ end of each AC port is connected to the corresponding converter valve via an external connection reactance L1, with or without a connection reactance L1.
In one embodiment of the invention, each converter valve includes a direct current port formed by a DC+ end and a DC-end, and an alternating current port formed by an AC+ end and an AC-end. The ac ports of the converter valves are connected to the isolation transformer, and the DC ports may independently form an external DC port, or may be connected in parallel (i.e., dc+ ends are connected together, DC-ends are connected together), or in series (dc+ ends of one converter valve are connected to DC-ends of another converter valve, and so on).
In one embodiment of the invention, at least one of the at least two ac ports is a new converter valve, the others are other converter valves (e.g., converter valve 2. Converter valve N in fig. 1), the new converter valve is structurally different from the other converter valves, wherein,
the other converter valves are modular multilevel converters MMC, first device serial H-bridge structures and second device serial H-bridge structures.
The structure of the novel converter valve in this embodiment will be described below.
In this embodiment, the novel converter valve (i.e., the novel converter valve in fig. 1) comprises a smoothing reactor L2, one or more switch capacitor valve banks that can be connected in parallel, and one or more novel series valve banks that can be connected in parallel, wherein,
the switch capacitor valve bank is connected with the novel series valve bank in parallel, and the smoothing reactance L2 is connected with the switch capacitor valve bank and the novel series valve bank in series integrally after being connected in parallel.
In this embodiment, the novel serial valve group includes two upper bridge arms and two lower bridge arms, one end of one upper bridge arm is connected with one end of one lower bridge arm through a connection midpoint, and one end of the other upper bridge arm is connected with one end of the other lower bridge arm through another connection midpoint; the other end of one of the upper bridge arms is connected with the other end of the other upper bridge arm, the other end of one of the lower bridge arms is connected with the other end of the other lower bridge arm, wherein,
The upper bridge arm and the lower bridge arm comprise one or a plurality of first power switch modules connected in series.
In this embodiment, the first power switch module includes a full-control device T1, a diode D1, a voltage-sharing capacitor C1, and an energy-consuming element, where an anode of the diode D1 is connected to an anode of the full-control device T1, one end of the voltage-sharing capacitor C1 is connected to a cathode of the diode D1, the other end of the voltage-sharing capacitor C1 is connected to a cathode of the full-control device T1, one end of the energy-consuming element is connected to one end of the voltage-sharing capacitor C1, the other end of the energy-consuming element is connected to the other end of the voltage-sharing capacitor C1, and the full-control device T1 is connected in anti-parallel to the diode. The first power switch module further comprises a bypass element K1, one end of the bypass element K1 is connected to the anode of the full-control device T1, and the other end of the bypass element K1 is connected to the cathode of the full-control device T1.
The bypass element K1 has two functions, namely, the bypass fault first power switch module ensures the normal operation of other first power switch modules in the corresponding bridge arm; secondly, the bypass corresponds to the black module (namely, some first power switch modules cannot be electrified because of some reasons, such as the damage of the energy taking power supply), the black module does not work normally because the energy taking power supply does not work normally, the traditional controllable bypass switch does not have electric control to bypass the module, and the automatic bypass of the module is realized by adopting the overvoltage breakdown characteristic of a thyristor or a diode.
The bypass element K1 is any one or a combination of a plurality of mechanical switches, semiconductor switches and thyristors (for example, a parallel combination thereof), or K1 may not be provided. In particular, when T1 is an IGCT, K1 does not need to employ a thyristor, since IGCT has overvoltage breakdown and long-term current-passing characteristics of the thyristor, bypass of the black module can be achieved.
In this embodiment, the energy dissipation element is any one or a combination of an energy dissipation power supply, a first energy dissipation resistor and a switchable energy dissipation resistor, where the energy dissipation power supply is configured to obtain energy from the voltage-sharing capacitor C1 and supply power to the control circuit of the first power switch module.
As shown in fig. 2, when the energy dissipation element is an energy taking power source, the positive electrode+ of the energy taking power source is connected to the positive electrode of the voltage equalizing capacitor C1, and the negative electrode-is connected to the negative electrode of the voltage equalizing capacitor C1.
As shown in fig. 3, when the energy dissipation element is a first energy dissipation resistor, one end of the first energy dissipation resistor is connected to the positive electrode of the voltage-sharing capacitor C1, and the other end is connected to the negative electrode of the voltage-sharing capacitor C1.
As shown in fig. 4, when the energy dissipation element is a switchable energy dissipation resistor, the switchable energy dissipation resistor includes a second energy dissipation resistor and a switch (for example, the switch may be a switch with a smaller direct current to be cut off, such as a relay, a contactor, a circuit breaker, a semiconductor switch, etc.), one end of the switch is connected to one end of the second energy dissipation resistor, the other end of the switch is connected to the positive electrode of the voltage-sharing capacitor C1, the other end of the second energy dissipation resistor is connected to the negative electrode of the voltage-sharing capacitor C1, and switching control of the second energy dissipation resistor can be achieved through the set switch.
When the energy dissipation element is a combination of the energy dissipation power supply, the first energy dissipation resistor and the switchable energy dissipation resistor, the structure of the combination includes, but is not limited to, the following combination forms:
combination form one: as shown in fig. 5, the energy-saving power supply comprises a switchable energy-consuming resistor and an energy-taking power supply, wherein one end of a switch in the switchable energy-consuming resistor is connected with one end of a second energy-consuming resistor, and the other end of the switch is connected with the positive electrode +; the other end of the second energy consumption resistor is connected with the negative electrode of the energy taking power supply; the positive electrode of the energy-taking power supply is connected with the positive electrode of the voltage-sharing capacitor C1, and the negative electrode of the energy-taking power supply is connected with the negative electrode of the voltage-sharing capacitor C1, and in addition, in the combined form, the following changes can be also carried out on the switch:
one end of a switch in the switchable energy dissipation resistor is connected with the other end of the second energy dissipation resistor, and the other end of the switch in the switchable energy dissipation resistor is connected with the negative electrode of the energy taking power supply; one end of the second energy consumption resistor is connected with the positive electrode of the energy taking power supply.
And a second combination form: as shown in fig. 6, the energy-saving capacitor comprises a first energy-consuming resistor and an energy-taking power supply, wherein one end of the first energy-consuming resistor is connected with the positive electrode of the energy-taking power supply, the other end of the first energy-consuming resistor is connected with the negative electrode of the energy-taking power supply, the positive electrode of the energy-taking power supply is connected with the positive electrode of the voltage-sharing capacitor C1, and the negative electrode of the first energy-consuming resistor is connected with the negative electrode of the voltage-sharing capacitor C1.
And a third combination form: as shown in fig. 7, the energy-saving capacitor comprises a first energy-saving resistor, an energy-taking power supply and a switchable energy-saving resistor, wherein one end of the first energy-saving resistor is connected with the positive electrode of the energy-taking power supply, the other end of the first energy-saving resistor is connected with the negative electrode of the energy-taking power supply, the positive electrode of the energy-taking power supply is connected with the positive electrode of the voltage-sharing capacitor C1, and the negative electrode of the first energy-saving resistor is connected with the negative electrode of the voltage-sharing capacitor C1; one end of the switch is connected with one end of the second energy dissipation resistor, the other end of the switch is connected with one end of the first energy dissipation resistor, and the other end of the second energy dissipation resistor is connected with the other end of the first energy dissipation resistor.
One end of the switch is connected with the other end of the second energy dissipation resistor, the other end of the switch is connected with the other end of the first energy dissipation resistor, and one end of the second energy dissipation resistor is connected with one end of the first energy dissipation resistor.
In this embodiment, when the upper bridge arm and the lower bridge arm each include a first power switch module:
in the upper bridge arm, an anode of a full-control device T1 in the first power switch module is used as the other end of the upper bridge arm, and a cathode of the full-control device T1 in the first power switch module is used as one end of the upper bridge arm;
In the lower bridge arm, an anode of a full-control device T1 in the first power switch module is used as one end of the lower bridge arm, and a cathode of the full-control device T1 in the first power switch module is used as the other end of the lower bridge arm.
In this embodiment, when the upper bridge arm and the lower bridge arm each include a plurality of first power switch modules connected in series:
in the upper bridge arm, a plurality of full-control devices T1 are connected in series, the anode of a first full-control device T1 in a first power switch module is used as the other end of the upper bridge arm, the cathode of the full-control device T1 in a last power switch module is used as one end of the upper bridge arm, and the anode of the previous full-control device T1 in the rest full-control devices T1 is connected with the cathode of the previous full-control device T1;
in the lower bridge arm, a plurality of full-control devices T1 are connected in series, the anode of a first full-control device T1 in a first power switch module is used as one end of the lower bridge arm, the cathode of the full-control device T1 in a last power switch module is used as the other end of the lower bridge arm, and among the rest full-control devices T1, the anode of the latter full-control device T1 is connected with the cathode of the last full-control device T1.
In this embodiment, one end of the switch capacitor bank is connected to the other end of the upper bridge arm, and the other end of the switch capacitor bank is connected to the other end of the lower bridge arm;
The switched capacitor valve bank comprises one or more second power switch modules connected in series.
In this embodiment, when the switched capacitor valve bank includes a second power switch module:
one end of the second power switch module is used as one end of the switch capacitor valve bank, and the other end of the second power switch module is used as the other end of the switch capacitor valve bank;
in this embodiment, when the switched capacitor valve bank includes a plurality of second power switch modules connected in series:
one end of the first second power switch module is used as one end (positive electrode plus end) of the switch capacitor valve group, the other end of the last second power switch module is used as the other end (negative electrode-end) of the switch capacitor valve group, and one end of the next second power switch module is connected with the other end of the last second power switch module in the rest second power switch modules.
In this embodiment, the second power switch module is any one of a half-bridge circuit, a full-bridge circuit and a hybrid module, where the hybrid module is a module formed by connecting the half-bridge circuit and the full-bridge circuit in series. Next, the structures of the half-bridge circuit, the full-bridge circuit, and the hybrid module will be described in detail.
In the present embodiment, the fully controlled device T1 may be an Insulated Gate bipolar transistor (Insulated GateBipolarTransistor, IGBT), an Integrated Gate commutated thyristor (Integrated Gate-CommutatedThyristor, IGCT), a Field effect transistor (Field-Effect Transistor, FET), etc
As shown in fig. 8, when the second power switch module is a half-bridge circuit, the half-bridge circuit includes a capacitor C2 and two full-control devices T2, wherein a cathode of one full-control device T2 is connected to an anode of the other full-control device T2, one end of the capacitor C2 is connected to an anode of one full-control device T2, and the other end of the capacitor C2 is connected to a cathode of the other full-control device T2, wherein the anode of the other full-control device T2 serves as one end corresponding to the second power module, and the cathode of the other full-control device T2 serves as the other end corresponding to the second power module. Wherein, each full-control device T2 is connected with a diode in anti-parallel.
The half-bridge circuit further comprises a bypass element K2, one end of the bypass element K2 is connected to the anode of the full-control device T2, and the other end of the bypass element K2 is connected to the cathode of the full-control device T2.
The bypass element K2 has two functions, namely, the bypass fault second power switch module ensures the normal operation of other second power switch modules in the corresponding bridge arm; secondly, the bypass corresponds to the black module (namely, some second power switch modules cannot be electrified because of some reasons, such as the damage of the energy taking power supply), the black module does not work normally because the energy taking power supply does not work normally, the traditional controllable bypass switch does not have electric control to bypass the module, and the automatic bypass of the module is realized by adopting the overvoltage breakdown characteristic of a thyristor or a diode.
The bypass element K2 is any one or a combination of a plurality of mechanical switches, semiconductor switches and thyristors (for example, a parallel combination thereof), or K2 may not be configured. In particular, when T2 is an IGCT, the K2 need not employ thyristors, since IGCT has overvoltage breakdown and long-term current-through characteristics of thyristors, bypass of the black module can be achieved.
In this embodiment, the full control device T2 may be IGBT, IGCT, FET or the like.
As shown in fig. 9, when the second power switch module is a full-bridge circuit, the full-bridge circuit includes a first bridge arm, a second bridge arm and a capacitor C3, where the first bridge arm and the second bridge arm each include two full-control devices T3; the cathode of one full-control device T3 of the first bridge arm is connected with the anode of the other full-control device T3 of the first bridge arm through a connecting point;
the cathode of one full-control device T3 of the second bridge arm is connected with the anode of the other full-control device T3 of the first bridge arm through a connecting point; the anode of one of the full-control devices T3 of the first bridge arm is connected with the anode of one of the full-control devices T3 of the second bridge arm; the cathode of the other full-control device T3 of the first bridge arm is connected with the cathode of the other full-control device T3 of the second bridge arm;
One end of the capacitor C3 is connected with the anode of one full-control device T3 of the second bridge arm, and the other end of the capacitor C3 is connected with the cathode of the other full-control device T3 of the second bridge arm; the connection point of the first bridge arm is used as one end corresponding to the second power module, and the connection point of the second bridge arm is used as the other end corresponding to the second power module. Each full-control device T3 is connected with a diode in anti-parallel.
The half-bridge circuit further comprises a bypass element K3, one end of the bypass element K3 is connected to the anode of the full-control device T3, and the other end of the bypass element K3 is connected to the cathode of the full-control device T3.
The bypass element K3 has two functions, namely, the bypass fault second power switch module ensures the normal operation of other second power switch modules in the corresponding bridge arm; secondly, the bypass corresponds to the black module (namely, some second power switch modules cannot be electrified because of some reasons, such as the damage of the energy taking power supply), the black module does not work normally because the energy taking power supply does not work normally, the traditional controllable bypass switch does not have electric control to bypass the module, and the automatic bypass of the module is realized by adopting the overvoltage breakdown characteristic of a thyristor or a diode.
The bypass element K3 is any one or a combination of a plurality of mechanical switches, semiconductor switches and thyristors (for example, a parallel combination thereof), or K3 may not be configured. In particular, when T3 is an IGCT, K3 does not need to employ a thyristor, since IGCT has overvoltage breakdown and long-term current-passing characteristics of the thyristor, bypass of the black module can be achieved.
In one embodiment of the present invention, as shown in fig. 10, the switched capacitor bank includes a hybrid module including a first number of half-bridge circuits in series and a second number of full-bridge circuits in series, wherein the first number of half-bridge circuits in series is in series with the second number of full-bridge circuits in series.
When the first number and the second number are both 1, the cathode of the other full-control device T2 in the half-bridge circuit is connected with the connection point of the first bridge arm in the full-bridge circuit, the anode of the other full-control device T2 in the half-bridge circuit is used as one end of the switch capacitor valve bank, and the connection point of the second bridge arm in the full-bridge circuit is used as the other end of the switch capacitor valve bank.
When the first number and the second number are both larger than 1, in the first number of half-bridge circuits in series and the second number of half-bridge circuits in series, the cathode of the other full-control device T2 in the last half-bridge circuit is connected with the connection point of the first bridge arm in the first full-bridge circuit, the anode of the other full-control device T2 in the first half-bridge circuit is used as one end of the switch capacitor bank, and the connection point of the second bridge arm in the last full-bridge circuit is used as the other end of the switch capacitor bank. In the rest half-bridge circuits, the anode of the other full-control device T2 in the latter half-bridge circuit is connected with the cathode of the other full-control device T2 in the former half-bridge circuit. In the rest of the full-bridge circuits, the connection point of the first bridge arm in the latter full-bridge circuit is connected with the connection point of the second bridge arm in the former full-bridge circuit.
In this embodiment, the switch capacitor bank utilizes a module (e.g., a second power module or a hybrid module) to make the dc supporting capacitors (e.g., capacitor C2 in fig. 8 and capacitor C3 in fig. 9) distributed inside the module, and when the dc bus is shorted, the module can block to avoid the capacitor discharge to increase the short-circuit current; the module can be switched actively, so that voltage equalizing of the voltage equalizing capacitor is facilitated; the module switching can realize ZVS and quasi-ZCS of the novel series valve group.
In one embodiment of the invention, the whole isolation transformer is required to be provided with a novel converter valve connected with one AC port, and converter valve circuits connected with other AC ports can be novel converter valves, modular multilevel converters MMC, a first device serial H-bridge structure, a second device serial H-bridge structure and the like. The modular multilevel converter MMC, the first device serial H-bridge structure and the second device serial H-bridge structure are described in detail below.
In one embodiment of the present invention, as shown in fig. 11, the modular multilevel converter MMC includes two parallel converter legs, where each converter leg includes an upper leg and a lower leg, and one end of the upper leg of each converter leg is connected with one end of the lower leg. The other ends of the upper bridge arms of the two converter bridge arms are connected, and the other ends of the lower bridge arms of the two converter bridge arms are connected.
The upper bridge arm and the lower bridge arm of each converter bridge arm comprise half-bridge cascading modules and inductors L3, one end of each inductor L3 of each upper bridge arm is connected with one end of a corresponding half-bridge cascading module, and one end of each inductor L3 of each lower bridge arm is connected with one end of the corresponding half-bridge cascading module; the other end of the inductor L3 of the upper bridge arm of each converter bridge arm is connected with the other end of the inductor L3 of the corresponding lower bridge arm through a connecting midpoint; the half-bridge cascade module comprises n cascaded half-bridge circuits (i.e. a plurality of half-bridge circuits are serially connected in sequence). In the two bridge arms, two connecting midpoints are respectively connected with an AC+ end and an AC-end of the isolation transformer.
For the upper bridge arm, one cascade connection point of the first half bridge circuit is used as the other end of a half bridge cascade module, the other end of the half bridge cascade module is connected with one end of an inductor L4, and the other end of the inductor L4 is a DC+ end corresponding to a converter valve; the other cascade connection point of the nth half-bridge circuit is connected with one end of the corresponding inductor L3 as one end of the half-bridge cascade module. In the rest of the half-bridge circuits, one cascade connection point of each half-bridge circuit (the cathode of one full-control device in the half-bridge circuit is connected to the cascade connection point) is connected with the other cascade connection point of the last bridge circuit (the cathode of the other full-control device in the half-bridge circuit is connected to the cascade connection point).
For the lower bridge arm, one cascade connection point of the first half-bridge circuit is used as one end of the half-bridge cascade module to be connected with one end of a corresponding inductor L3. The other end of the half-bridge cascade module is connected with one end of another inductor L4, the other end of the inductor L4 is a DC-end corresponding to a converter valve, namely, the other cascade connection point of the nth half-bridge circuit is used as the other end of the half-bridge cascade module to be connected with one end of another inductor L4. In the rest of the half-bridge circuits, one cascade connection point of each half-bridge circuit is connected with the other cascade connection point of the last bridge circuit.
In one embodiment of the present invention, as shown in fig. 12, the first device serial H-bridge structure includes two parallel bridge arms, where each bridge arm is divided into an upper bridge arm and a lower bridge arm, one end of the upper bridge arm is connected to one end of the lower bridge arm through a connection midpoint, the two connection midpoints are respectively connected to an ac+ end and an AC-end of a corresponding isolation transformer, the other ends of the two upper bridge arms are connected to one end of an inductor L5 (the other end of the inductor L5 is a dc+ end of a corresponding converter valve) after being connected to each other, and the other ends of the two lower bridge arms are connected to one end of another inductor L5 (the other end of the inductor is a DC-end of a corresponding converter valve) after being connected to each other. The upper bridge arm and the lower bridge arm comprise all-controlled devices T4 connected in series, and the mode of connecting a plurality of all-controlled devices T4 in series is as follows:
For the upper bridge arm, the anode of the first full-control device T4 is used as the other end of the upper bridge arm, the cathode of the last full-control device T4 is used as one end of the upper bridge arm, and among the rest full-control devices T4, the anode of the latter full-control device T4 is connected with the cathode of the former full-control device T4;
for the lower bridge arm, the anode of the first full-control device T4 is used as one end of the lower bridge arm, the cathode of the last full-control device T4 is used as the other end of the lower bridge arm, and among the rest full-control devices T4, the anode of the latter full-control device T4 is connected with the cathode of the former full-control device T4.
In addition, in the embodiment, a capacitor C5 is disposed between one ends of the two inductors L5, and a diode is connected in anti-parallel to each fully-controlled device T4.
In one embodiment of the present invention, as shown in fig. 13, the difference between the second device serial H-bridge structure and the first device serial H-bridge structure is that the switch capacitor bank set described above is disposed between one ends of two inductors L5 of the second device serial H-bridge structure, and the second power module in the switch capacitor bank set is a half-bridge circuit.
In the present invention, as shown in fig. 14, there is further provided a control method of a novel high-voltage dc transformer, the method being implemented based on the dc transformer, wherein the method includes:
Selecting a transmission power control strategy among alternating current ports of the direct current transformer;
generating reference wave voltages uacx of the 1 st to N th alternating current ports of the direct current transformer according to a transmission power control strategy;
according to the reference wave voltage uacx (x=1, 2, …, N), obtaining the output voltage of the corresponding switch capacitor valve group and the reference wave voltage |uacx| in the converter valve x;
and controlling the output of the modulated wave waveforms of the novel series valve and the switched capacitor valve bank according to the reference wave voltage uacx and the reference wave voltage uacx.
The above-described method is described in detail below
Step 1: selecting a transmission power control strategy (rectangular wave phase shift control, trapezoidal wave phase shift control, step wave phase shift control, triangular wave phase shift control, sine wave amplitude phase control and the like) among all AC ports of the direct current transformer;
step 2: generating reference wave voltages uacx (x=1, 2, …, N) for the 1 st to N th AC ports of the dc transformer according to the selected transmission power control strategy;
step 3: according to the reference wave voltage uacx, obtaining the output voltage (+, -voltage between poles) of a switch capacitor valve bank corresponding to the converter valve x, namely the reference wave voltage |uacx| (namely, absolute value of uacx), and the switch capacitor valve bank generates the same output voltage according to the |uacx|;
Step 4: the novel serial valve group switches output states at the zero crossing point of uacx, and is specific: when uacx is from positive to negative, in FIG. 1, the upper left and lower right bridge arms of the novel series valve bank are turned off, and the upper left and lower right bridge arms are turned on; when uacx goes from negative to positive, in FIG. 1, the left lower and right upper bridge arms of the novel series valve bank are turned off, and the left upper and right lower bridge arms are turned on. Each bridge arm of the novel series valve group is formed by connecting a plurality of series modules in series, and in the process of switching on and switching off, all the full-control devices T1 of all the series modules in one bridge arm can act simultaneously or can exist successively.
Step 5: disregarding the waveform of the valve group of the I uacx, controlling the output voltage of the switch capacitor valve group to ensure that the output voltage is t before the on-off state of the novel series valve group is switched cq The time is reduced to 0, and ZVS and quasi-ZCS (ZVS and quasi-ZCS are one form of soft switch) of the novel series valve bank are realized. Where t cq An artificially set amount of lead time to offset the effects of control system communication delays, dead time of the power semiconductor switching devices, etc.
Step 6: the output voltage of the switch capacitor valve group is controlled to be t after the on-off state of the novel series valve is switched zh Time rises to |uacx| to recover the output voltage of the switched capacitor valve bank as modulation after ZVS and quasi-ZCS of the novel series valve bank are realized Wave voltage |uacx|. Where t zh An artificially set amount of lag time to offset the effects of control system communication delay, power semiconductor switching device dead time, etc.
The method from step 1 to step 6 has the functions of controlling what voltage is output by the switch capacitor valve bank, controlling when the novel series valve bank switches the output state, and realizing the novel series valve bank soft switch.
On the other hand, the invention also provides a control method of the novel high-voltage direct-current transformer, wherein the direct-current transformer adopts the direct-current transformer, and the control method comprises the following steps:
determining a receiving end and a transmitting end of a direct current transformer;
and determining a control strategy according to the types of the receiving end and the sending end.
Specific:
the hybrid high-voltage direct-current transformer is based on phase shift control, namely, phase difference exists between square wave voltages output by a high-voltage side and a low-voltage side, and the power magnitude and direction are controlled by adjusting the phase difference. Single phase shift control, double phase shift control, triple phase shift control, etc. may be employed. Exemplary, for example, single phase shift control is: each converter valve outputs square wave or trapezoidal wave voltage with a step wave level between the AC ports, and a phase difference (phase shift angle) exists between the voltages of the AC ports, and the power magnitude and direction are controlled by adjusting the phase difference. Through the control, the size and the direction of the power can be controlled, and the transmitted power among the DC ports is indirectly controlled, so that the following control targets are realized:
One side of the high-voltage side and the low-voltage side of the direct-current transformer is a transmitting end, and the other side is a receiving end. When the receiving end is a load (electric equipment, a resistance load or a constant power load, etc.), and the sending end is a voltage source, the control strategy is to determine the direct current voltage control of the receiving end, namely: the deviation value obtained by the difference between the receiving end direct current voltage reference value and the feedback value is output by the PI regulator to obtain a phase shift angle; when the receiving end and the transmitting end are both voltage sources, the control strategy is to determine the power control of the receiving end/transmitting end, namely: the power reference value of the receiving end/transmitting end is differenced with the feedback value to obtain a deviation value, and the deviation value is output by a PI regulator to obtain a phase shift angle; when the receiving end is a voltage source and the transmitting end is a power source, the control strategy is to control the direct current voltage of the transmitting end, namely: the deviation value obtained by the difference between the reference value and the feedback value of the direct current voltage at the transmitting end is outputted by the PI regulator to obtain the phase shift angle.
The invention is illustrated in the following by way of example only.
As shown in fig. 15, a novel high-voltage dc transformer includes a high-voltage side dc port and a low-voltage side dc port, a high-voltage side AC port of an isolation transformer is connected to a high-voltage side novel converter valve, and 2 low-voltage side AC ports are respectively connected to 2 low-voltage side novel converter valves. The direct current ports of the low-pressure side 2 novel converter valves are connected in parallel, so that a low-pressure direct current port is formed. The parallel connection can improve the current capacity and realize the tolerance of the converter valve to low-voltage high current.
The novel series valve ZVS and quasi-ZCS have extremely low switching loss, and adopt IGCT to realize high current and low loss. In contrast, the on-state current of the switch capacitor valve bank is small, the on-state loss is extremely low, and the IGBT is adopted to realize low switching loss. The IGBTdi/dt is smaller, and the reverse recovery speed of the novel series valve diode D1 is limited, so that the first power module does not need to be provided with a clamping circuit and an anode reactance which are necessary for the traditional IGCT module, the cost, the volume and the loss are reduced, and the reliability is improved.
As shown in fig. 15, since only the lower pipe of the series module (first power module) adopts the fully controlled device, the usage amount of the fully controlled device is greatly reduced compared with that of the MMC. The upper tube of the series module is a low-current diode, and the cost is far lower than that of the diode of the MMC sub-module. The voltage-equalizing capacitor of the series module has very small charge and discharge power, so the capacitance is very small and the volume is small. Ideally, the charging power of the equalizing capacitor mainly comes from the stray inductance follow current of the bridge arm, the part of power is very small, and the energy-taking power source (the energy-consuming element in the case is the energy-taking power source) can be consumed, so that the self-energy-taking problem of the novel serial valve group is solved. In addition, the voltage-sharing capacitor can only be charged through the diode, but not discharged through the series diode, so that the capacity value of the voltage-sharing capacitor does not influence the ZVS characteristic of the series valve, and the capacity value of the voltage-sharing capacitor in the case can be larger than that of the traditional series valve (but still is far smaller than that of the MMC sub-module, namely the half-bridge circuit), and the effect of series voltage sharing is further ensured.
Soft switching method: as shown in fig. 16 (fig. 16 shows, from top to bottom, a graph of the high-side AC port voltage, the low-side AC port voltage, the high-side novel series valve block modulation wave voltage, the high-side switched capacitor valve block voltage, the low-side novel series valve block modulation wave voltage, and the low-side switched capacitor valve block voltage over time t in order), phase shift control is employed. The voltage polarity of the modulating wave of the novel series valve is turned over, and the modulating wave voltage of the switched capacitor valve bank is reduced to 0, so that ZVS and quasi-ZCS of the novel series valve bank can be realized.
As can be seen from fig. 16, the modulation wave voltage of the switched capacitor valve group is stepwise changed, so that dv/dt can be reduced. In the interval of the reduction of the output voltage of the switch capacitor valve bank, the smoothing reactance is used for freewheeling, so that the stability of the output current at the DC side of the DC transformer is ensured.
The present invention is not limited to the above-mentioned embodiments, but is not limited to the above-mentioned embodiments, and any simple modification, equivalent changes and modification made to the above-mentioned embodiments according to the technical matters of the present invention can be made by those skilled in the art without departing from the scope of the present invention.

Claims (14)

1. A novel high-voltage direct-current transformer comprises an isolation transformer and a converter valve, wherein,
the isolation transformer comprises at least two alternating current ports, and each alternating current port is correspondingly connected with one or more converter valves.
2. The novel high voltage dc transformer of claim 1 wherein at least one of at least two of said ac ports is a novel converter valve.
3. The novel high voltage dc transformer of claim 1 wherein said novel converter valve comprises a smoothing reactor, one or more switched capacitor valve banks in parallel and one or more novel series valve banks in parallel, wherein,
the switch capacitor valve bank is connected with the novel series valve bank in parallel, and the smoothing reactance is connected with the switch capacitor valve bank and the novel series valve bank in series in parallel.
4. The novel high-voltage direct-current transformer according to claim 3, wherein the novel series valve bank comprises two upper bridge arms and two lower bridge arms, one end of one upper bridge arm is connected with one end of one lower bridge arm through a connecting midpoint, and one end of the other upper bridge arm is connected with one end of the other lower bridge arm through another connecting midpoint; the other end of one of the upper bridge arms is connected with the other end of the other upper bridge arm, the other end of one of the lower bridge arms is connected with the other end of the other lower bridge arm, wherein,
The upper bridge arm and the lower bridge arm comprise one or a plurality of first power switch modules connected in series.
5. The novel high-voltage direct-current transformer according to claim 4, wherein the first power switch module comprises a full control device T1, a diode D1, a voltage-equalizing capacitor C1 and energy dissipation elements, wherein,
the anode of the diode D1 is connected with the anode of the full-control device T1, one end of the voltage-sharing capacitor C1 is connected with the cathode of the diode D1, the other end of the voltage-sharing capacitor C1 is connected with the cathode of the full-control device T1, one end of the energy-consuming element is connected with one end of the voltage-sharing capacitor C1, and the other end of the energy-consuming element is connected with the other end of the voltage-sharing capacitor C1.
6. The novel high voltage dc transformer of claim 5 wherein, when said upper leg and lower leg each include a first power switch module:
in the upper bridge arm, an anode of a full-control device T1 in the first power switch module is used as the other end of the upper bridge arm, and a cathode of the full-control device T1 in the first power switch module is used as one end of the upper bridge arm;
in the lower bridge arm, an anode of a full-control device T1 in the first power switch module is used as one end of the lower bridge arm, and a cathode of the full-control device T1 in the first power switch module is used as the other end of the lower bridge arm.
7. The novel high voltage dc transformer of claim 5 wherein, when the upper leg and lower leg each comprise a plurality of first power switch modules in series:
in the upper bridge arm, a plurality of full control devices T1 are connected in series, the anode of a first full control device T1 in a first power switch module is used as the other end of the upper bridge arm, and the cathode of the full control device T1 in the last first power switch module is used as one end of the upper bridge arm;
in the lower bridge arm, a plurality of full-control devices T1 are connected in series, the anode of a first full-control device T1 in a first power switch module is used as one end of the lower bridge arm, and the cathode of the full-control device T1 in a last power switch module is used as the other end of the lower bridge arm.
8. The novel high-voltage direct current transformer according to any one of claims 4-7, wherein one end of the switch capacitor bank is connected with the other end of the upper bridge arm, and the other end of the switch capacitor bank is connected with the other end of the lower bridge arm.
9. The novel high voltage DC transformer of claim 8, wherein said switch capacitor bank comprises one or more second power switch modules connected in series, wherein,
When the switched capacitor valve bank comprises a second power switch module:
one end of the second power switch module is used as one end of the switch capacitor valve bank, and the other end of the second power switch module is used as the other end of the switch capacitor valve bank;
when the switched capacitor valve bank comprises a plurality of second power switch modules connected in series:
one end of the first second power switch module is used as one end of the switch capacitor valve group, and the other end of the last second power switch module is used as the other end of the switch capacitor valve group;
the second power switch module is any one of a half-bridge circuit, a full-bridge circuit and a hybrid module.
10. The novel high voltage DC transformer of claim 8 wherein said switched capacitor valve block comprises a hybrid module comprising a first number of half-bridge circuits in series and a second number of full-bridge circuits in series, wherein,
the first number of half-bridge circuits in series is in series with the second number of full-bridge circuits in series.
11. The novel high-voltage direct-current transformer according to any one of claims 5-7, wherein the energy consumption element is any one or combination of an energy-taking power supply, a first energy consumption resistor and a switchable energy consumption resistor,
The energy-taking power supply is used for obtaining energy from the voltage-sharing capacitor and supplying power to the control circuit of the first power switch module.
12. A control method of a novel high-voltage direct current transformer employing the direct current transformer according to any one of claims 1 to 11, the control method comprising:
the output voltage of the switch capacitor valve bank is controlled to be t before the on-off state of the novel series valve bank is switched cq The time is reduced to 0, and the novel series valve group soft switch is realized.
13. A control method of a novel high-voltage direct current transformer employing the direct current transformer according to any one of claims 1 to 11, the control method comprising:
determining a receiving end and a transmitting end of a direct current transformer;
and determining a control strategy according to the types of the receiving end and the sending end.
14. The control method of a novel high voltage dc transformer according to claim 13, wherein determining the control strategy according to the types of the receiving end and the transmitting end comprises:
when the receiving end is a power source and the transmitting end is a voltage source, the control strategy is to determine direct current voltage control of the receiving end;
when the receiving end and the transmitting end are both voltage sources, the control strategy is to determine the power control of the receiving end/transmitting end;
when the receiving end is a voltage source and the transmitting end is a power source, the control strategy is to control the direct current voltage of the transmitting end.
CN202310021948.4A 2023-01-06 2023-01-06 Novel high-voltage direct-current transformer and control method Pending CN116054585A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116760303A (en) * 2023-08-24 2023-09-15 国网浙江省电力有限公司电力科学研究院 High-voltage direct-current transformer and fault redundancy control method thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116760303A (en) * 2023-08-24 2023-09-15 国网浙江省电力有限公司电力科学研究院 High-voltage direct-current transformer and fault redundancy control method thereof
CN116760303B (en) * 2023-08-24 2023-12-26 国网浙江省电力有限公司电力科学研究院 High-voltage direct-current transformer and fault redundancy control method thereof

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