Starting method and starting device of alternating current converter

Abstract

The invention provides a starting method and a starting device of an alternating current converter, which are used for charging a sub-module capacitor in the alternating current converter by controlling locking and starting of different station-level control systems, and finally realizing starting of the alternating current converter. In the process of starting the alternating current converter by adopting different station level control systems, the impact on the alternating current converter is small, so that the alternating current converter can be stably and reliably started. In other words, the starting method provided by the invention is high in reliability. According to the invention, the first station-level control subsystems in the first station-level control system, the second station-level control system and the third station-level control system are started at the same time, so that the breakdown risk of a power electronic device in the matching unit due to large pressure bearing can be avoided; and meanwhile, the risk of burnout of the capacitor caused by continuous charging of the neutron module capacitor in the matching unit due to bearing of large direct-current voltage is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of power transmission, and particularly to a starting method and a starting device for an AC converter. Background Art

[0002] The AC converter is the core device of flexible AC power transmission and can be mainly used in scenarios such as flexible low-frequency AC power transmission and flexible interconnection of AC power grids. The flexible low-frequency AC power transmission technology can greatly improve the transmission capacity of transmission lines and reduce the electrical distance of the lines by selecting a transmission frequency lower than the power frequency, and has unique advantages in scenarios such as medium- and long-distance new energy collection and transmission. The flexible interconnection technology of AC power grids uses power electronic devices to achieve power flow regulation, fault isolation, and short-circuit current control between regional power grids, and is an effective means to solve problems such as wide fault propagation range, excessive short-circuit current, and inability to mutually supply power in rigid partitioned interconnection in large-scale power grids. The proposed AC converter has a simple topology. Compared with traditional M3C converters and back-to-back MMCs, the number of sub-modules and devices used is less, which can improve the technical economy of the flexible AC power transmission system.

[0003] The charging of the sub-module capacitor in the AC converter is the first step in the startup of the AC converter and is also the guarantee for the stable operation of the AC converter. The startup methods provided by related technologies directly start the AC converter through a circuit breaker. When the AC converter is started, the impact on the AC converter is relatively large, resulting in the inability of the AC converter to start stably and reliably. That is to say, the startup methods provided by related technologies have low reliability. Summary of the Invention

[0004] In order to solve the problem of low reliability in the prior art, the present application provides a starting method and a starting device for an AC converter.

[0005] In a first aspect, the present application provides a starting method for an AC converter, which may include:

[0006] Controlling the AC converter to be blocked.

[0007] Controlling the blocking and starting of the first station-level control system, the second station-level control system, and the third station-level control system to charge the sub-module capacitor in the AC converter.

[0008] Wherein, the AC converter includes a first conversion unit, a matching unit, and a second conversion unit connected in sequence. The first station-level control system is used to control the matching unit, the second station-level control system is used to control the first conversion unit, and the third station-level control system is used to control the second conversion unit.

[0009] Optionally, the first AC terminal of the AC converter is connected to the first AC system through a series-connected starting branch and a first circuit breaker, and the second AC terminal of the AC converter is connected to the second AC system through a second circuit breaker. Among them, the starting branch includes a parallel-connected starting resistor and a third circuit breaker.

[0010] In some possible implementation manners, controlling the blocking and starting of the first substation-level control system, the second substation-level control system, and the third substation-level control system to charge the sub-module capacitors in the AC converter includes:

[0011] Close the first circuit breaker, and open the second circuit breaker and the third circuit breaker. The first AC system charges the sub-module capacitors through the first circuit breaker and the starting resistor.

[0012] Maintain the first circuit breaker closed and the second circuit breaker open, and close the third circuit breaker. The first AC system charges the sub-module capacitors through the first circuit breaker and the third circuit breaker.

[0013] Simultaneously start the first substation-level control subsystem in the first substation-level control system, the second substation-level control system, and the third substation-level control system to charge the sub-module capacitors. Among them, the first substation-level control subsystem is used to control the actual voltage of the second AC system.

[0014] Control the blocking of the first substation-level control subsystem and the third substation-level control subsystem in the third substation-level control system, and start the second substation-level control subsystem in the third substation-level control system to charge the sub-module capacitors.

[0015] In an example, simultaneously starting the first substation-level control subsystem in the first substation-level control system, the second substation-level control system, and the third substation-level control system to charge the sub-module capacitors includes:

[0016] Control the matching unit to output a voltage difference through the first substation-level control system. Among them, the voltage difference is used to indicate the difference between the output voltage / input voltage of the first conversion subunit in the first conversion unit and the input voltage / output voltage of the second conversion subunit in the second conversion unit.

[0017] Through the second substation-level control system, control the active power exchanged between the AC converter and the first AC system according to the voltage of the sub-module capacitors, and control the reactive power exchanged between the AC converter and the first AC system according to the preset reactive power target value of the first AC system or the voltage target value on the side of the AC converter close to the first AC system.

[0018] Through the first substation-level control subsystem, control the frequency of the second AC system according to the preset target frequency of the second AC system, and control the actual voltage of the second AC system according to the preset target voltage of the second AC system and the first feedforward voltage. Wherein, the voltage value of the first feedforward voltage is equal to the voltage value of the target voltage.

[0019] In another example, control the first substation-level control subsystem and the third substation-level control subsystem in the third substation-level control system to lock out, and start the second substation-level control subsystem in the third substation-level control system to charge the sub-module capacitors, including:

[0020] Control the first substation-level control subsystem and the third substation-level control subsystem to lock out.

[0021] Through the second substation-level control subsystem, control the frequency of the second AC system according to the preset target frequency of the second AC system, and control the actual voltage of the second AC system according to the preset target voltage of the second AC system and the second feedforward voltage. Wherein, the voltage value of the second feedforward voltage is equal to the voltage value of the actual voltage.

[0022] Furthermore, controlling the lockout and startup of the first substation-level control system, the second substation-level control system, and the third substation-level control system to charge the sub-module capacitors in the AC converter further includes:

[0023] Control the first circuit breaker, the second circuit breaker, and the third circuit breaker to connect the AC converter to the second AC system.

[0024] Optionally, the second AC system is a power generation system or a load.

[0025] In some other possible implementation manners, the second AC system is a power grid, and the startup method further includes:

[0026] Control the first substation-level control subsystem and the second substation-level control subsystem in the third substation-level control system to lock out, and control the active power and reactive power exchanged between the second AC system and the AC converter through the third substation-level control subsystem in the third substation-level control system.

[0027] Exemplarily, controlling the first substation-level control subsystem and the second substation-level control subsystem in the third substation-level control system to lock out, and controlling the active power and reactive power exchanged between the second AC system and the AC converter through the third substation-level control subsystem in the third substation-level control system includes:

[0028] Control the first substation-level control subsystem and the second substation-level control subsystem to lock out, and start the third substation-level control subsystem.

[0029] Through the third substation-level control subsystem, the active power exchanged between the second AC system and the AC converter is controlled according to the preset active power target value of the second AC system, and the reactive power exchanged between the second AC system and the AC converter is controlled according to the preset reactive power target value of the second AC system.

[0030] In a second aspect, the present application provides a starting device for an AC converter, which may include:

[0031] A first control module for controlling the locking of the AC converter.

[0032] A second control module for controlling the locking and starting of the first substation-level control system, the second substation-level control system, and the third substation-level control system to charge the sub-module capacitors in the AC converter.

[0033] Among them, the AC converter includes a first conversion unit, a matching unit, and a second conversion unit connected in sequence. The first substation-level control system is used to control the matching unit, the second substation-level control system is used to control the first conversion unit, and the third substation-level control system is used to control the second conversion unit.

[0034] Optionally, the first AC terminal of the AC converter is connected to the first AC system through a series-connected starting branch and a first circuit breaker, and the second AC terminal of the AC converter is connected to the second AC system through a second circuit breaker. Among them, the starting branch includes a parallel-connected starting resistor and a third circuit breaker.

[0035] In some possible implementation manners, the second control module is specifically used for:

[0036] Closing the first circuit breaker and opening the second circuit breaker and the third circuit breaker, and the first AC system charges the sub-module capacitors through the first circuit breaker and the starting resistor.

[0037] Maintaining the first circuit breaker closed and the second circuit breaker open, closing the third circuit breaker, and the first AC system charges the sub-module capacitors through the first circuit breaker and the third circuit breaker.

[0038] Simultaneously starting the first substation-level control subsystem in the first substation-level control system, the second substation-level control system, and the third substation-level control system to charge the sub-module capacitors. Among them, the first substation-level control subsystem is used to control the actual voltage of the second AC system.

[0039] Controlling the locking of the first substation-level control subsystem and the third substation-level control subsystem in the third substation-level control system, and starting the second substation-level control subsystem in the third substation-level control system to charge the sub-module capacitors.

[0040] In an example, the second control module is used for:

[0041] The output voltage difference of the matching unit is controlled by the first substation-level control system. The voltage difference is used to indicate the difference between the output voltage / input voltage of the first conversion subunit in the first conversion unit and the input voltage / output voltage of the second conversion subunit in the second conversion unit.

[0042] Through the second substation-level control system, the active power exchanged between the AC converter and the first AC system is controlled according to the voltage of the sub-module capacitor, and the reactive power exchanged between the AC converter and the first AC system is controlled according to the preset reactive power target value of the first AC system or the voltage target value on the side of the AC converter close to the first AC system.

[0043] Through the first substation-level control subsystem, the frequency of the second AC system is controlled according to the preset target frequency of the second AC system, and the actual voltage of the second AC system is controlled according to the preset target voltage of the second AC system and the first feed-forward voltage. The voltage value of the first feed-forward voltage is equal to the voltage value of the target voltage.

[0044] In another example, the second control module is used for:

[0045] Controlling the first substation-level control subsystem and the third substation-level control subsystem to lock out.

[0046] Through the second substation-level control subsystem, the frequency of the second AC system is controlled according to the preset target frequency of the second AC system, and the actual voltage of the second AC system is controlled according to the preset target voltage of the second AC system and the second feed-forward voltage. The voltage value of the second feed-forward voltage is equal to the voltage value of the actual voltage.

[0047] Furthermore, the second control module is also used for:

[0048] Controlling the first circuit breaker, the second circuit breaker, and the third circuit breaker to connect the AC converter to the second AC system.

[0049] Optionally, the second AC system can be a power generation system or a load, etc.

[0050] In another possible implementation, the second AC system is a power grid, and the starting device further includes a third control module.

[0051] The third control module is used for: controlling the first substation-level control subsystem and the second substation-level control subsystem in the third substation-level control system to lock out, and controlling the active power and reactive power exchanged between the second AC system and the AC converter through the third substation-level control subsystem of the third substation-level control system.

[0052] Furthermore, the third control module is specifically used for:

[0053] Control the locking of the first substation-level control subsystem and the second substation-level control subsystem, and start the third substation-level control subsystem.

[0054] Through the third substation-level control subsystem, control the active power exchanged between the second AC system and the AC converter according to the preset active power target value of the second AC system, and control the reactive power exchanged between the second AC system and the AC converter according to the preset reactive power target value of the second AC system.

[0055] On the other hand, the present application also provides a computer device, including: one or more processors.

[0056] The processor is used to execute one or more programs.

[0057] When the one or more programs are executed by the one or more processors, the startup method as described above is implemented.

[0058] On the other hand, the present application also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed, the startup method as described above is implemented.

[0059] Compared with the prior art, the beneficial effects of the present application are:

[0060] In the startup method of the AC converter provided by the present application, by controlling the locking and startup of different substation-level control systems, the capacitors of the sub-modules in the AC converter are charged, and finally the startup of the AC converter is realized. During the process of starting the AC converter by adopting different substation-level control systems in the present application, the impact on the AC converter is small, so that the AC converter can be started stably and reliably. That is to say, the startup method provided by the present application has high reliability.

[0061] The present application simultaneously starts the first substation-level control subsystem in the first substation-level control system, the second substation-level control system, and the third substation-level control system, which can avoid the breakdown risk of the power electronic devices in the matching unit due to high pressure, and at the same time avoid the risk of capacitor burning caused by continuous charging of the sub-module capacitors in the matching unit due to large DC voltage.

[0062] The present application controls the frequency of the second AC system according to the preset target frequency of the second AC system through the first substation-level control subsystem, and controls the actual voltage of the second AC system according to the preset target voltage of the second AC system and the first feed-forward voltage, which can avoid the instability of the first substation-level control subsystem caused by the failure to establish the voltage of the second AC system before the startup of the first substation-level control subsystem, and further avoid the charging failure of the AC converter.

[0063] This application uses the second station-level control subsystem to control the frequency of the second AC system according to the preset target frequency of the second AC system, and control the actual voltage of the second AC system according to the preset target voltage of the second AC system and the second feed-forward voltage. When a short-circuit fault occurs in the second AC system, the voltage fault condition of the second AC system can be quickly reflected to the second station-level control subsystem, and the short-circuit current of the second AC system can be limited through the second feed-forward voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions in this application or the prior art, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0065] Figure 1 It is a schematic structural diagram of an AC converter in an embodiment of this application;

[0066] Figure 2 It is a schematic structural diagram of the connection between the AC converter and the AC system in an embodiment of this application;

[0067] Figure 3 It is a schematic flowchart of a method for starting an AC converter in an embodiment of this application;

[0068] Figure 4 It is a schematic structural diagram of a starting device for an AC converter in an embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0069] The following will describe the technical solutions in this application in conjunction with the drawings.

[0070] The terms "first", "second", etc. in the description of the embodiments, claims, and drawings of this application are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0071] It should be understood that in this application, "at least one (item)" means one or more, and "a plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that there can be three relationships. For example, "A and / or B" can mean: only A exists, only B exists, and both A and B exist at the same time. Among them, A and B can be singular or plural. The character " / " generally represents an "or" relationship between the front and back associated objects. "At least one (one) of the following" or similar expressions refer to any combination of these items, including any combination of single items (ones) or plural items (ones). For example, at least one (one) of a, b, or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a, b, and c", where a, b, and c can be single or multiple.

[0072] Embodiment 1:

[0073] The embodiment of the present application provides a starting method for an AC converter. Among them, an AC converter is a converter that can convert alternating current into alternating current. As Figure 1 shown, the AC converter 100 includes a first conversion unit 1, a matching unit 7, and a second conversion unit 2 connected in series in sequence.

[0074] The first conversion unit 1 is used to: generate a first half-wave voltage, and invert the polarity of the first half-wave voltage to generate a first alternating current voltage U with positive and negative alternation a .

[0075] The second conversion unit 2 is used to: generate a second half-wave voltage, and invert the polarity of the second half-wave voltage to generate a second alternating current voltage U with positive and negative alternation u .

[0076] The matching unit 7 is used to: generate a first matching voltage. Among them, the first matching voltage is the difference between the sum of the first half-wave voltage and the second half-wave voltage.

[0077] Optionally, the polarities of the first half-wave voltage and the second half-wave voltage are the same, and can be positive voltages with specific amplitudes and frequencies, and the positive voltage is composed of the positive half-cycle of a sine wave with the specific amplitude and frequency.

[0078] Optionally, the first alternating current voltage U a is used as the input voltage of the AC / AC converter 100 and the second alternating current voltage U u is used as the output voltage of the AC / AC converter 100. Or, the first alternating current voltage U a is used as the output voltage of the AC / AC converter 100 and the second alternating current voltage U u is used as the input voltage of the AC / AC converter 100. It can be seen that the AC / AC converter 100 can be a single-phase converter.

[0079] In a possible implementation, referring to Figure 1 , the first conversion unit 1 includes a first conversion subunit 11 and a first inversion unit 12 connected in parallel.

[0080] The first conversion subunit 11 is configured to: generate a first half-wave voltage according to one or more cascaded sub-modules.

[0081] The first inversion unit 12 is configured to: invert the polarity of the first half-wave voltage according to one or more series-connected semiconductor switches at a first preset frequency and a first preset phase angle to generate a first alternating current voltage U a .

[0082] In another possible implementation, referring to Figure 1 , the second conversion unit 2 includes a second conversion subunit 21 and a second inversion unit 22 connected in parallel.

[0083] The second conversion subunit 21 is configured to: generate a second half-wave voltage according to one or more cascaded sub-modules.

[0084] The second inversion unit 22 is configured to: invert the polarity of the second half-wave voltage according to one or more series-connected semiconductor switches at a second preset frequency and a second preset phase angle to generate a second alternating current voltage U u .

[0085] The above-mentioned sub-module can be a half-bridge sub-module or a full-bridge sub-module, which is not limited in the embodiments of the present application. Both the half-bridge sub-module and the full-bridge sub-module include a sub-module capacitor and a semiconductor device, which will not be described in detail in the present application.

[0086] As Figure 2 shown, the first alternating current terminal of the alternating current converter 100 is connected to the first alternating current system S1 through a series-connected starting branch and a first circuit breaker QF1, and the second alternating current terminal of the alternating current converter 100 is connected to the second alternating current system S2 through a second circuit breaker QF2. Among them, the starting branch includes a starting resistor R and a third circuit breaker QF3 connected in parallel.

[0087] As Figure 3 shown, the starting method 200 of the alternating current converter includes the following steps:

[0088] Step S1: Control the blocking of the alternating current converter 100.

[0089] Step S2: Control the blocking and starting of the first substation-level control system, the second substation-level control system, and the third substation-level control system to charge the sub-module capacitor in the alternating current converter 100.

[0090] The first station-level control system is used to control the matching unit 7, the second station-level control system is used to control the first conversion unit 1, and the third station-level control system is used to control the second conversion unit 2.

[0091] In a possible implementation, the locking and starting of the first station-level control system, the second station-level control system, and the third station-level control system in step S2 above are used to charge the sub-module capacitors in the AC converter 100, including:

[0092] Step S21: Close the first circuit breaker QF1, and open the second circuit breaker QF2 and the third circuit breaker QF3. The first AC system S1 charges the sub-module capacitors through the first circuit breaker QF1 and the starting resistor.

[0093] Step S22: Keep the first circuit breaker QF1 closed and the second circuit breaker QF2 open, and close the third circuit breaker QF3. The first AC system S1 charges the sub-module capacitors through the first circuit breaker QF1 and the third circuit breaker QF3.

[0094] Step S23: Simultaneously start the first station-level control subsystem in the first station-level control system, the second station-level control system, and the third station-level control system to charge the sub-module capacitors. Among them, the first station-level control subsystem is used to control the actual voltage of the second AC system S2.

[0095] Step S24: Control the locking of the first station-level control subsystem and the third station-level control subsystem in the third station-level control system, and start the second station-level control subsystem in the third station-level control system to charge the sub-module capacitors.

[0096] In an example, simultaneously starting the first station-level control subsystem in the first station-level control system, the second station-level control system, and the third station-level control system in step S23 to charge the sub-module capacitors includes:

[0097] Step S231: Control the output voltage difference of the matching unit through the first station-level control system. Among them, the voltage difference is used to indicate the difference between the output voltage / input voltage of the first conversion subunit in the first conversion unit and the input voltage / output voltage of the second conversion subunit in the second conversion unit.

[0098] Step S232: Through the second station-level control system, control the active power exchanged between the AC converter 100 and the first AC system S1 according to the voltage of the sub-module capacitors, and control the reactive power exchanged between the AC converter 100 and the first AC system S1 according to the preset reactive power target value of the first AC system S1 or the voltage target value on the side of the AC converter 100 close to the first AC system S1.

[0099] Step S233: Through the first station-level control subsystem, control the frequency of the second AC system S2 according to the preset target frequency of the second AC system S2, and control the actual voltage of the second AC system S2 according to the preset target voltage of the second AC system S2 and the first feed-forward voltage. Wherein, the voltage value of the first feed-forward voltage is equal to the voltage value of the target voltage.

[0100] In another example, in step S24, control the first station-level control subsystem and the third station-level control subsystem in the third station-level control system to be blocked, and start the second station-level control subsystem in the third station-level control system to charge the sub-module capacitor, including:

[0101] Step S241: Control the first station-level control subsystem and the third station-level control subsystem to be blocked.

[0102] Step S242: Through the second station-level control subsystem, control the frequency of the second AC system S2 according to the preset target frequency of the second AC system S2, and control the actual voltage of the second AC system S2 according to the preset target voltage of the second AC system S2 and the second feed-forward voltage. Wherein, the voltage value of the second feed-forward voltage is equal to the voltage value of the actual voltage.

[0103] Further, step S2 controls the blocking and starting of the first station-level control system, the second station-level control system, and the third station-level control system to charge the sub-module capacitor in the AC converter 100, and further includes:

[0104] Step S25: Control the first circuit breaker QF1, the second circuit breaker QF2, and the third circuit breaker QF3 to connect the AC converter 100 to the second AC system S2.

[0105] Optionally, the second AC system S2 is a power generation system or a load.

[0106] In some other possible implementation manners, the second AC system S2 is a power grid, and the starting method 200 further includes:

[0107] Control the first station-level control subsystem and the second station-level control subsystem in the third station-level control system to be blocked, and control the active power and reactive power exchanged between the second AC system S2 and the AC converter 100 through the third station-level control subsystem in the third station-level control system; specifically including:

[0108] Control the first station-level control subsystem and the second station-level control subsystem to be blocked, and start the third station-level control subsystem.

[0109] Through the third substation-level control subsystem, the active power exchanged between the second AC system S2 and the AC converter 100 is controlled according to the preset active power target value of the second AC system S2, and the reactive power exchanged between the second AC system S2 and the AC converter 100 is controlled according to the preset reactive power target value of the second AC system S2.

[0110] Embodiment 2:

[0111] Based on the same inventive concept, an embodiment of the present application further provides a starting device for the AC converter 100. Among them, the AC converter 100 can refer to the above introduction and Figure 1 , which will not be elaborated herein in this embodiment of the present application.

[0112] As Figure 4 shown, the starting device 300 includes:

[0113] The first control module 301 is used to control the locking of the AC converter 100.

[0114] The second control module 302 is used to control the locking and starting of the first substation-level control system, the second substation-level control system, and the third substation-level control system, and charge the sub-module capacitors in the AC converter 100.

[0115] In some possible implementation manners, the second control module 302 is specifically used for:

[0116] Closing the first circuit breaker QF1, and opening the second circuit breaker QF2 and the third circuit breaker QF3. The first AC system S1 charges the sub-module capacitors through the first circuit breaker QF1 and the starting resistor.

[0117] Maintaining the first circuit breaker QF1 closed and the second circuit breaker QF2 open, closing the third circuit breaker QF3, and the first AC system S1 charges the sub-module capacitors through the first circuit breaker QF1 and the third circuit breaker QF3.

[0118] Simultaneously starting the first substation-level control subsystem in the first substation-level control system, the second substation-level control system, and the third substation-level control system to charge the sub-module capacitors. Among them, the first substation-level control subsystem is used to control the actual voltage of the second AC system S2.

[0119] Controlling the locking of the first substation-level control subsystem and the third substation-level control subsystem in the third substation-level control system, and starting the second substation-level control subsystem in the third substation-level control system to charge the sub-module capacitors.

[0120] In an example, the second control module 302 is used for:

[0121] Control the output voltage difference of the matching unit through the first substation-level control system. The voltage difference is used to indicate the difference between the output voltage / input voltage of the first conversion subunit in the first conversion unit and the input voltage / output voltage of the second conversion subunit in the second conversion unit.

[0122] Through the second substation-level control system, control the active power exchanged between the AC converter 100 and the first AC system S1 according to the voltage of the sub-module capacitor, and control the reactive power exchanged between the AC converter 100 and the first AC system S1 according to the preset reactive power target value of the first AC system S1 or the voltage target value on the side of the AC converter 100 close to the first AC system S1.

[0123] Through the first substation-level control subsystem, control the frequency of the second AC system S2 according to the preset target frequency of the second AC system S2, and control the actual voltage of the second AC system S2 according to the preset target voltage of the second AC system S2 and the first feed-forward voltage. The voltage value of the first feed-forward voltage is equal to the voltage value of the target voltage.

[0124] In another example, the second control module 302 is used for:

[0125] Control the first substation-level control subsystem and the third substation-level control subsystem to lock out.

[0126] Through the second substation-level control subsystem, control the frequency of the second AC system S2 according to the preset target frequency of the second AC system S2, and control the actual voltage of the second AC system S2 according to the preset target voltage of the second AC system S2 and the second feed-forward voltage. The voltage value of the second feed-forward voltage is equal to the voltage value of the actual voltage.

[0127] Furthermore, the second control module 302 is also used for:

[0128] Control the first circuit breaker QF1, the second circuit breaker QF2 and the third circuit breaker QF3 to connect the AC converter 100 to the second AC system S2.

[0129] Optionally, the second AC system S2 can be a power generation system or a load, etc.

[0130] In another possible implementation, the second AC system S2 is a power grid, and the starting device further includes a third control module 303.

[0131] The third control module 303 is used for: controlling the first substation-level control subsystem and the second substation-level control subsystem in the third substation-level control system to lock out, and controlling the active power and reactive power exchanged between the second AC system S2 and the AC converter 100 through the third substation-level control subsystem of the third substation-level control system.

[0132] Further, the third control module 303 is specifically configured to:

[0133] Lock the first substation-level control subsystem and the second substation-level control subsystem, and start the third substation-level control subsystem.

[0134] Through the third substation-level control subsystem, control the active power exchanged between the second AC system S2 and the AC converter 100 according to the preset active power target value of the second AC system S2, and control the reactive power exchanged between the second AC system S2 and the AC converter 100 according to the preset reactive power target value of the second AC system S2.

[0135] Embodiment 3:

[0136] Based on the same inventive concept, an embodiment of the present application further provides a computer device, which includes a processor and a memory. The memory is used to store a computer program, and the computer program includes program instructions. The processor is used to execute the program instructions stored in the computer storage medium. The processor may be a Central Processing Unit (CPU), or may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, and is suitable for implementing one or more instructions. Specifically, it is suitable for loading and executing one or more instructions in the computer storage medium to implement the corresponding method flow or corresponding function, so as to implement the steps of the startup method provided in the above embodiment.

[0137] Embodiment 4:

[0138] Based on the same inventive concept, an embodiment of the present application also provides a computer-readable storage medium, specifically a computer-readable storage medium (Memory). A computer-readable storage medium is a memory device in a computer device and is used to store programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the computer device and, of course, the extended storage medium supported by the computer device. The computer-readable storage medium provides a storage space, and the operating system of the terminal is stored in this storage space. Moreover, one or more instructions suitable for being loaded and executed by the processor are stored in this storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory or a non-volatile memory, such as at least one disk memory. One or more instructions stored in the computer-readable storage medium can be loaded and executed by the processor to implement the steps of the startup method provided in the above embodiment.

[0139] Those skilled in the art should understand that the embodiments of the application can be provided as a method, a system, or a computer program product. Therefore, the application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program codes.

[0140] The application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the specified functions in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0141] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the specified functions in Figure 1 one flow or multiple flows and / or blocks Figure 1The functions specified in one or more boxes.

[0142] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide for implementing the steps of the functions specified in one Figure 1 one process or more processes and / or boxes Figure 1 or more boxes.

[0143] The above are only examples of the application and are not intended to limit the application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the application are included within the scope of the claims of the invention pending approval.

Claims

1. A method for starting an AC converter, characterized in that: include: Controlling the AC converter to lock; wherein the AC converter comprises a first conversion unit, a matching unit and a second conversion unit connected in sequence; Control the locking and starting of the first station-level control system, the second station-level control system and the third station-level control system to charge the submodule capacitors in the AC converter; wherein the first station-level control system is used to control the matching unit, the second station-level control system is used to control the first conversion unit, and the third station-level control system is used to control the second conversion unit.

2. The startup method according to claim 1, characterized in that: The first AC end of the AC converter is connected to the first AC system through a series starting branch and a first circuit breaker, and the second AC end of the AC converter is connected to the second AC system through a second circuit breaker; wherein the starting branch includes a parallel starting resistor and a third circuit breaker.

3. The startup method according to claim 2, characterized in that: The method of controlling the locking and starting of the first station-level control system, the second station-level control system, and the third station-level control system to charge the submodule capacitor in the AC converter includes: The first circuit breaker is closed, and the second circuit breaker and the third circuit breaker are opened, and the first AC system charges the submodule capacitor through the first circuit breaker and the starting resistor; Maintaining the first circuit breaker closed and the second circuit breaker open, closing the third circuit breaker, and allowing the first AC system to charge the submodule capacitor through the first circuit breaker and the third circuit breaker; Simultaneously start the first station-level control system, the second station-level control system and the first station-level control subsystem in the third station-level control system to charge the submodule capacitor; wherein the first station-level control subsystem is used to control the actual voltage of the second AC system; The first station-level control subsystem and the third station-level control subsystem in the third station-level control system are controlled to be locked, and the second station-level control subsystem in the third station-level control system is started to charge the submodule capacitor.

4. The startup method according to claim 3, characterized in that: The simultaneously starting the first station-level control system, the second station-level control system, and the first station-level control subsystem in the third station-level control system to charge the submodule capacitor includes: Controlling the output voltage difference of the matching unit by the first station-level control system; wherein the voltage difference is used to indicate the difference between the output voltage / input voltage of the first conversion subunit in the first conversion unit and the input voltage / output voltage of the second conversion subunit in the second conversion unit; By means of the second station-level control system, the active power exchanged between the AC converter and the first AC system is controlled according to the voltage of the submodule capacitor, and the reactive power exchanged between the AC converter and the first AC system is controlled according to a preset reactive power target value of the first AC system or a voltage target value of the AC converter close to the first AC system; Through the first station-level control subsystem, the frequency of the second AC system is controlled according to a preset target frequency of the second AC system, and the actual voltage of the second AC system is controlled according to a preset target voltage of the second AC system and a first feed-forward voltage; wherein a voltage value of the first feed-forward voltage is equal to a voltage value of the target voltage.

5. The startup method according to claim 3, characterized in that: The controlling the first station-level control subsystem and the third station-level control subsystem in the third station-level control system to lock, and starting the second station-level control subsystem in the third station-level control system to charge the submodule capacitor includes: Controlling the first station-level control subsystem and the third station-level control subsystem to be locked; Through the second station-level control subsystem, the frequency of the second AC system is controlled according to the preset target frequency of the second AC system, and the actual voltage of the second AC system is controlled according to the preset target voltage of the second AC system and the second feed-forward voltage; wherein the voltage value of the second feed-forward voltage is equal to the voltage value of the actual voltage.

6. The startup method according to claim 2, characterized in that: The controlling the locking and starting of the first station-level control system, the second station-level control system and the third station-level control system to charge the submodule capacitor in the AC converter also includes: The first circuit breaker, the second circuit breaker and the third circuit breaker are controlled to connect the AC converter to the second AC system.

7. The startup method according to claim 2, characterized in that: The second AC system is a power grid, and the startup method further includes: The first station-level control subsystem and the second station-level control subsystem in the third station-level control system are controlled to be locked, and the active power and reactive power exchanged between the second AC system and the AC converter are controlled through the third station-level control subsystem of the third station-level control system.

8. The startup method according to claim 7, characterized in that: The method of controlling the first station-level control subsystem and the second station-level control subsystem in the third station-level control system to be locked, and controlling the active power and reactive power exchanged between the second AC system and the AC converter through the third station-level control subsystem of the third station-level control system, comprises: Controlling the first station-level control subsystem to be locked and the second station-level control subsystem to be locked, and starting the third station-level control subsystem; Through the third station-level control subsystem, the active power exchanged between the second AC system and the AC converter is controlled according to the preset active power target value of the second AC system, and the reactive power exchanged between the second AC system and the AC converter is controlled according to the preset reactive power target value of the second AC system.

9. The starting method according to any one of claims 3 to 6, characterized in that: The second AC system is a power generation system or a load.

10. A starting device for an AC converter, characterized in that: include: A first control module, used for controlling the AC converter to lock; wherein the AC converter comprises a first conversion unit, a matching unit and a second conversion unit connected in sequence; The second control module is used to control the locking and starting of the first station-level control system, the second station-level control system and the third station-level control system to charge the sub-module capacitors in the AC converter; wherein the first station-level control system is used to control the matching unit, the second station-level control system is used to control the first conversion unit, and the third station-level control system is used to control the second conversion unit.

11. The starting device according to claim 10, characterized in that: The first AC end of the AC converter is connected to the first AC system through a series starting branch and a first circuit breaker, and the second AC end of the AC converter is connected to the second AC system through a second circuit breaker; wherein the starting branch includes a parallel starting resistor and a third circuit breaker.

12. The starting device according to claim 11, characterized in that: The second control module is specifically used for: The first circuit breaker is closed, and the second circuit breaker and the third circuit breaker are opened, and the first AC system charges the submodule capacitor through the first circuit breaker and the starting resistor; Maintaining the first circuit breaker closed and the second circuit breaker open, closing the third circuit breaker, and allowing the first AC system to charge the submodule capacitor through the first circuit breaker and the third circuit breaker; Simultaneously start the first station-level control system, the second station-level control system and the first station-level control subsystem in the third station-level control system to charge the submodule capacitor; wherein the first station-level control subsystem is used to control the actual voltage of the second AC system; The first station-level control subsystem and the third station-level control subsystem in the third station-level control system are controlled to be locked, and the second station-level control subsystem in the third station-level control system is started to charge the submodule capacitor.

13. The starting device according to claim 12, characterized in that: The second control module is used for: Controlling the output voltage difference of the matching unit by the first station-level control system; wherein the voltage difference is used to indicate the difference between the output voltage / input voltage of the first conversion subunit in the first conversion unit and the input voltage / output voltage of the second conversion subunit in the second conversion unit; By means of the second station-level control system, the active power exchanged between the AC converter and the first AC system is controlled according to the voltage of the submodule capacitor, and the reactive power exchanged between the AC converter and the first AC system is controlled according to a preset reactive power target value of the first AC system or a voltage target value of the AC converter close to the first AC system; Through the first station-level control subsystem, the frequency of the second AC system is controlled according to a preset target frequency of the second AC system, and the actual voltage of the second AC system is controlled according to a preset target voltage of the second AC system and a first feed-forward voltage; wherein a voltage value of the first feed-forward voltage is equal to a voltage value of the target voltage.

14. The starting device according to claim 12, characterized in that: The second control module is used for: Controlling the first station-level control subsystem and the third station-level control subsystem to be locked; Through the second station-level control subsystem, the frequency of the second AC system is controlled according to the preset target frequency of the second AC system, and the actual voltage of the second AC system is controlled according to the preset target voltage of the second AC system and the second feed-forward voltage; wherein the voltage value of the second feed-forward voltage is equal to the voltage value of the actual voltage.

15. The starting device according to claim 11, characterized in that: The second control module is also used for: The first circuit breaker, the second circuit breaker and the third circuit breaker are controlled to connect the AC converter to the second AC system.

16. The starting device according to claim 11, characterized in that: The second AC system is a power grid, and the starting device further includes a third control module; The third control module is used to control the locking of the first station-level control subsystem and the second station-level control subsystem in the third station-level control system, and to control the active power and reactive power exchanged between the second AC system and the AC converter through the third station-level control subsystem of the third station-level control system.

17. The starting device according to claim 16, characterized in that: The third control module is specifically used for: Controlling the first station-level control subsystem to be locked and the second station-level control subsystem to be locked, and starting the third station-level control subsystem; Through the third station-level control subsystem, the active power exchanged between the second AC system and the AC converter is controlled according to the preset active power target value of the second AC system, and the reactive power exchanged between the second AC system and the AC converter is controlled according to the preset reactive power target value of the second AC system.

18. The starting device according to any one of claims 12 to 15, characterized in that: The second AC system is a power generation system or a load.

19. A computer device, characterized in that: include: one or more processors; The processor is used to store one or more programs; When the one or more programs are executed by the one or more processors, the startup method according to any one of claims 1 to 9 is implemented.

20. A computer-readable storage medium, characterized in that: A computer program is stored thereon, and when the computer program is executed, the startup method according to any one of claims 1 to 9 is implemented.

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