WO2019184213A1 - 模块化变流器及其控制方法、风力发电机组 - Google Patents

模块化变流器及其控制方法、风力发电机组 Download PDF

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Publication number
WO2019184213A1
WO2019184213A1 PCT/CN2018/101740 CN2018101740W WO2019184213A1 WO 2019184213 A1 WO2019184213 A1 WO 2019184213A1 CN 2018101740 W CN2018101740 W CN 2018101740W WO 2019184213 A1 WO2019184213 A1 WO 2019184213A1
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Prior art keywords
converter
bus
module
modules
switch
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PCT/CN2018/101740
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English (en)
French (fr)
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符松格
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北京天诚同创电气有限公司
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Publication of WO2019184213A1 publication Critical patent/WO2019184213A1/zh

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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
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
    • H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
    • H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
    • H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M5/4585—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only having a rectifier with controlled 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
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/40—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc
    • H02M5/42—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters
    • H02M5/44—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac
    • H02M5/453—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/458—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases with intermediate conversion into dc by static converters using discharge tubes or semiconductor devices to convert the intermediate dc into ac using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • 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
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/70—Wind energy
    • Y02E10/76—Power conversion electric or electronic aspects

Definitions

  • the present disclosure generally relates to the field of converter technology, and more particularly to a modular converter and its control method, a wind turbine.
  • Modular converters use standard modular cabinet units. Each cabinet unit can independently assume the function of the converter, and can expand the capacity of the converter by paralleling each other to meet the different generators. Net output power.
  • modular converters usually use independent DC busbars, that is, the DC busbars of each cabinet unit are independent of each other and do not affect each other, which is equivalent to direct parallel connection of each cabinet unit, which reduces the control of the entire converter. Responsiveness and may trigger control oscillations.
  • An exemplary embodiment of the present disclosure is to provide a modular converter and a control method thereof and a wind power generator capable of realizing online switching of a separate DC bus operating state of a modular converter and a parallel DC bus operating state, thereby Achieve online control of the modular converter's control gain and grid-connected power quality.
  • a modular converter including: a plurality of converter modules and a plurality of on-off switch modules; the plurality of converter modules are connected in parallel Connecting, and corresponding to the plurality of on/off switch modules, the DC bus of each converter module is connected to each other via a corresponding on/off switch module; each on/off switch module is turned on in response to the received control signal Or turning off; wherein, when the two on-off switch modules are simultaneously turned on, the convergence path formed between the DC bus bars of the two converter modules corresponding to the two on-off switch modules that are turned on is turned on; When the on/off switch module is turned off, the DC bus of the converter module corresponding to one of the on/off switch modules that is turned off is disconnected from the bus path of the DC bus of the other converter modules.
  • a method of controlling a modular converter that includes a plurality of converter modules and a plurality of on-off switch modules;
  • the flow unit modules are connected in parallel and are in one-to-one correspondence with the plurality of on-off switch modules, and the DC bus bars of each of the current transformer modules are connected to each other via a corresponding on-off switch module;
  • the method includes: During operation of the flow device, a control signal is sent to the plurality of on-off switch modules to turn the plurality of on-off switch modules on or off; wherein, when the two on-off switch modules are simultaneously turned on, The bus path formed between the DC bus bars of the two converter modules corresponding to the two on-off switch modules that are turned on is turned on; when one on/off switch module is turned off, corresponding to an on/off switch module that is turned off The DC bus of the converter module is disconnected from the bus path of the DC bus of the other converter modules.
  • a method of controlling a modular converter as described above comprising: if voltages between DC busbars of two converter modules are unbalanced, The two on-off switch modules corresponding to the two converter modules in which the voltage imbalance is present are simultaneously turned on for dynamically adjusting the voltage of the DC bus of the two converter modules in which the voltage imbalance exists.
  • a computer readable storage medium storing a computer program that, when executed by a processor, implements a method of controlling a modular converter as described above.
  • a controller including: a processor; a memory storing a computer program, and when the computer program is executed by the processor, implementing the control as described above Modular converter method.
  • a wind power generator set is provided, the wind power generator set including a modular current transformer as described above.
  • the modular converter and the control method thereof and the wind power generator according to the exemplary embodiments of the present disclosure can realize online switching of the independent DC bus operating state of the modular converter and the parallel DC bus operating state, thereby implementing the online adjustment module Control converter gain and grid-connected power quality.
  • the modular converter when the modular converter is in the parallel DC bus operation state, it can also avoid the circulation between the converter module in the running state and the converter module in the online hot standby state; realize the DC of the converter module Dynamic regulation of the voltage of the busbar; prevention of overload caused by excessive charging speed of a pre-charging circuit during pre-charging; ensuring power electronics of other converter modules when a converter module has a short-circuit fault Safety.
  • FIG. 1 shows a schematic structural view of a modular converter according to an exemplary embodiment of the present disclosure
  • FIG. 2 shows a schematic structural view of a modular converter according to another exemplary embodiment of the present disclosure
  • FIG. 3 illustrates a schematic structural view of a modular converter according to another exemplary embodiment of the present disclosure
  • FIG. 4 shows a schematic diagram of a way of sinking between DC bus bars of any two converter modules, according to an exemplary embodiment of the present disclosure
  • FIG. 5 illustrates a flow chart of a method of controlling a modular converter, in accordance with an exemplary embodiment of the present disclosure.
  • FIG. 1 shows a schematic structural view of a modular converter according to an exemplary embodiment of the present disclosure.
  • a modular converter includes: N converter modules (eg, 10-1, 10-2, ..., 10-n) and N on and off Switching modules (eg, 20-1, 20-2, ..., 20-n), where N is an integer greater than one.
  • the modular converters have a modular structure, and each converter module can independently assume the function of the converter, that is, each converter module can independently realize the function of the converter.
  • the circuit configuration of the converter module shown in FIG. 1 is merely an example, and the circuit configuration of the converter module is not limited thereto.
  • the N converter modules are connected in parallel with each other, and the N converter modules are in one-to-one correspondence with the N on/off switch modules, and the DC bus bars of each converter module are connected to each other via a corresponding on/off switch module.
  • the DC bus of one of the converter modules is in turn via an on/off switch module corresponding to the one converter module and an on/off switch module corresponding to the other converter module. Connect to the DC bus of the other converter module.
  • Each on/off switch module is turned on or off in response to the received control signal, wherein when the two on/off switch modules are simultaneously turned on, the two converters corresponding to the two on/off switch modules that are turned on The bus path formed between the DC busbars of the module is turned on; when one on/off switch module is turned off, the DC bus of the converter module corresponding to one of the on/off switch modules that are turned off and the DC bus of the other converter modules The confluence path formed between them is broken.
  • each converter module can be separately formed as a cabinet unit.
  • the N converter modules are connected in parallel with each other, that is, the inputs of the N converter modules are connected to each other, and the outputs of the N converter modules are connected to each other.
  • the inputs of the N converter modules may each be connected to the output of the generator via a frame breaker, and the outputs of the N converter modules may each be connected to the input of the grid side transformer via another frame breaker. end.
  • the modular converter can be a three-level converter or a two-level converter. If the modular converter is a three-level converter, each converter module has a DC positive bus (DC+), a DC negative bus (DC-), and a DC neutral bus (NP), correspondingly, N
  • the direct current busbars of the converter modules are connected to each other via corresponding on-off switch modules, and the DC negative busbars of the N converter modules are connected to each other via corresponding on-off switch modules, and the DCs of the N converter modules are in DC
  • the sex buses are connected to each other via a corresponding on/off switch module.
  • each converter module has only a DC positive bus and a DC negative bus, and accordingly, the DC positive bus of the N converter modules is via a corresponding on/off switch
  • the modules are connected to each other, and the DC negative busbars of the N converter modules are connected to each other via a corresponding on/off switch module.
  • FIG. 2 shows a schematic structural view of a modular converter according to another exemplary embodiment of the present disclosure.
  • the modular converter is a three-level converter.
  • the circuit configuration of the converter module shown in FIG. 2 is merely an example, and the circuit configuration of the converter module is not limited thereto.
  • the circuit structure of the converter module can be as shown in FIG.
  • the on/off switch module includes: a first fully-controlled semiconductor device 201 and a freewheeling diode 202 connected in anti-parallel thereto, a second fully-controlled semiconductor device 203, and a freewheeling diode 204 connected in anti-parallel thereto, The third fully controlled semiconductor device 205 and the freewheeling diode 206 connected in anti-parallel thereto.
  • the collector of the first fully-controlled semiconductor device 201 is connected to the DC positive bus of the corresponding converter module, and the emitters of all the first fully-controlled semiconductor devices 201 are connected to each other;
  • the second fully-controlled semiconductor device The collector of 203 is connected to the DC neutral bus of the corresponding converter module, the emitters of all the second fully-controlled semiconductor devices 203 are connected to each other;
  • the collector of the third fully-controlled semiconductor device 205 is connected to the corresponding converter The DC negative bus of the module, the emitters of all the third fully-controlled semiconductor devices 205 are connected to each other.
  • the emitters of all of the first fully-controlled semiconductor devices 201 are connected to each other, the emitters of all the second fully-controlled semiconductor devices 203 are connected to each other, and all of the third fully-controlled semiconductor devices can be realized by various appropriate means.
  • the emitters of 205 are connected to each other.
  • the modular converter according to another exemplary embodiment of the present disclosure may further include: a first DC bus bar 30, a second DC bus bar 40, and a third DC bus bar 50, Specifically, the emitters of all the first fully-controlled semiconductor devices 201 are connected to the first DC bus bar 30 such that the emitters of all the first fully-controlled semiconductor devices 201 are connected to each other via the first DC bus bar 30.
  • the emitters of all the second fully-controlled semiconductor devices 203 are connected to the second DC bus bar 40 such that the emitters of all the second fully-controlled semiconductor devices 203 are connected to each other via the second DC bus bar 40; all third The emitters of the fully-controlled semiconductor device 205 are each connected to the third DC bus bar 50 such that the emitters of all the third fully-controlled semiconductor devices 205 are connected to each other via the third DC bus bar 50.
  • the on/off switch module receives the control signal, and substantially the first fully-controlled semiconductor device 201, the second fully-controlled semiconductor device 203, and the third fully-controlled semiconductor device 205 of the on/off switch module receive the control signal.
  • control signals received by the first fully-controlled semiconductor device 201, the second fully-controlled semiconductor device 203, and the third fully-controlled semiconductor device 205 of one on-off switch module at the same time may be the same.
  • the first fully-controlled semiconductor device 201, the second fully-controlled semiconductor device 203, and the third fully-controlled semiconductor device 205 may be the same type of fully-controlled semiconductor device.
  • the first fully-controlled semiconductor device 201, the second fully-controlled semiconductor device 203, and the third fully-controlled semiconductor device 205 may all be Insulated Gate Bipolar Transistors (IGBTs), or both Power field effect transistors (Power MOSFETs), or both integrated gate commutated thyristors (IGCTs).
  • IGBTs Insulated Gate Bipolar Transistors
  • Power MOSFETs Power field effect transistors
  • IGCTs integrated gate commutated thyristors
  • the on-off switch module may include: a fourth fully-controlled semiconductor device (not shown) and a freewheeling diode connected in anti-parallel thereto (not shown), a fifth fully controlled semiconductor device (not shown) and a freewheeling diode (not shown) connected in anti-parallel thereto.
  • the collector of the fourth fully-controlled semiconductor device is connected to the DC positive bus of the corresponding converter module, and the emitters of all the fourth fully-controlled semiconductor devices are connected to each other; the set of the fifth fully-controlled semiconductor device The electrodes are connected to the DC negative bus of the corresponding converter module, and the emitters of all of the fifth fully controlled semiconductor devices are connected to each other.
  • the fourth fully-controlled semiconductor device and the fifth fully-controlled semiconductor device may both be insulated gate bipolar transistors, or both are power field effect transistors, or both are integrated gate commutated thyristors.
  • the modular converter is a three-level converter
  • the on-off switch module includes: a first fully-controlled semiconductor device 201 and a freewheeling diode 202 and a second fully-controlled semiconductor device 203 connected in anti-parallel thereto And a freewheeling diode 204, a third fully controlled semiconductor device 205, and a freewheeling diode 206 connected in anti-parallel thereto.
  • the two on-off switch modules corresponding to the two converter modules with voltage imbalance are simultaneously turned on for The voltage of the DC bus of the two converter modules with voltage imbalance is dynamically adjusted.
  • the voltage imbalance between the DC busbars of the two converter modules may be, for example, the voltage between the DC positive bus and the DC neutral bus of the first converter module is higher than the second The voltage between the DC positive bus and the DC neutral bus of the converter module; or the voltage between the DC neutral bus and the DC negative bus of the first converter module is higher than the DC of the second converter module The voltage between the bus bar and the DC negative bus; or the voltage between the DC positive bus and the DC negative bus of the first converter module is higher than the DC positive bus and the DC negative bus of the second converter module Voltage.
  • the converter module 10-1 corresponds to the on/off switch module 20-1
  • the converter module 10-2 is The on/off switch module 20-2 corresponds.
  • the on/off switch module 20-1 and the on/off switch module 20-2 are both turned on (for example, respectively to the gate set of the first fully-controlled semiconductor device 201, the gate set of the second fully-controlled semiconductor device 203, or the third
  • the gate set of the fully-controlled semiconductor device 205 transmits a high-level signal
  • dynamic adjustment of the voltage of the DC bus of the converter module 10-1 and the converter module 10-2 can be realized.
  • the first converter module represents the converter module 10-1
  • the second converter module represents the converter module 10-2.
  • the first on/off switch module represents the on/off switch module 20-1
  • the second on/off switch module represents the on/off switch module 20-2.
  • the first change The first fully-controlled semiconductor device of the first on-off switch module corresponding to the current module is turned on, and the second fully-controlled semiconductor device of the second on-off switch module corresponding to the second converter module is turned on, Thereby forming a confluence loop from the DC positive bus of the first converter module to the DC positive bus of the second converter module, and forming a DC neutral bus from the second converter module to the first converter module The convergence loop of the DC neutral bus.
  • the first of the on/off switch module 20-1 is controlled.
  • the fully-controlled semiconductor device 201 is turned on, and at the same time, the second fully-controlled semiconductor device 203 of the on-off switch module 20-2 is controlled to be turned on, thereby forming a DC+ from the converter module 10-1 in sequence via the on-off switch module.
  • the first fully-controlled semiconductor device 201 of 20-1 and the freewheeling diode 202 of the switching module 20-2 are connected to the DC+ of the converter module 10-2, and sequentially pass through the NP of the converter module 10-2.
  • the second fully controlled semiconductor device 203 of the switch module 20-2 and the freewheeling diode 204 of the switch module 20-1 are connected to the sink circuit of the NP of the converter module 10-1.
  • the first fully controlled semiconductor of the on/off switch module 20-2 is controlled.
  • the device 201 is turned on, and at the same time, the second fully-controlled semiconductor device 203 that controls the on/off switch module 20-1 is turned on, thereby forming the first from the DC+ of the converter module 10-2 via the on/off switch module 20-2.
  • the second fully controlled semiconductor device 203 of 1 and the freewheeling diode 204 of the switching module 20-2 are connected to the sinking circuit of the NP of the converter module 10-2.
  • the voltage between the DC neutral bus and the DC negative bus of the first converter module is higher than the voltage between the DC neutral bus and the DC negative bus of the second converter module
  • the second fully-controlled semiconductor device of the first on/off switch module corresponding to the current module is turned on
  • the third fully-controlled semiconductor device of the second on-off switch module corresponding to the second converter module is turned on
  • the on/off switch module 20-1 is controlled.
  • the second fully-controlled semiconductor device 203 is turned on, and at the same time, the third fully-controlled semiconductor device 205 that controls the on-off switch module 20-2 is turned on, thereby forming an NP from the converter module 10-1 through the on-off switch in sequence.
  • the second fully-controlled semiconductor device 203 of the module 20-1 and the freewheeling diode 204 of the switching module 20-2 are connected to the NP of the converter module 10-2 and sequentially from the DC- of the converter module 10-2.
  • the semiconductor device 203 is turned on, and at the same time, the third fully-controlled semiconductor device 205 that controls the on/off switch module 20-1 is turned on, thereby forming the NP from the converter module 10-2 sequentially via the on/off switch module 20-2.
  • the second fully controlled semiconductor device 203 and the freewheeling diode 204 of the switching module 20-1 are connected to the NP of the converter module 10-1, and the DC- from the converter module 10-1 is sequentially passed through the on/off switch.
  • the second fully-controlled semiconductor device 205 of the module 20-1 and the freewheeling diode 206 of the switching module 20-2 are connected to the DC- confluence loop of the converter module 10-2.
  • the first converter The first fully-controlled semiconductor device of the first on-off switch module corresponding to the module is turned on, and the third fully-controlled semiconductor device of the second on-off switch module corresponding to the second converter module is turned on, thereby forming a sinking loop from the DC positive bus of the first converter module to the DC positive bus of the second converter module, and constituting a DC negative from the DC negative bus of the second converter module to the first converter module Bus circuit of the bus.
  • the voltage difference between the DC positive bus and the DC negative bus of the converter module 10-1 ie, the voltage difference between DC+ and DC-
  • the voltage difference between the bus bar and the DC negative bus bar controls the first fully-controlled semiconductor device 201 of the on-off switch module 20-1 to be turned on, and at the same time, controls the third fully-controlled semiconductor device of the on-off switch module 20-2.
  • 205 is turned on, thereby forming a DC+ from the current transformer module 10-1 to the current through the first full control type semiconductor device 201 of the on/off switch module 20-1 and the freewheeling diode 202 of the on/off switch module 20-2.
  • the on/off switch module is controlled.
  • the first fully-controlled semiconductor device 201 of 20-2 is turned on, and at the same time, the third fully-controlled semiconductor device 205 that controls the on-off switch module 20-1 is turned on, thereby forming DC+ from the converter module 10-2 in order.
  • a wind power generator set includes the modular current transformer described in the above exemplary embodiments.
  • the inputs of the modular converter i.e., the inputs of each converter module
  • FIG. 5 illustrates a flow chart of a method of controlling a modular converter, in accordance with an exemplary embodiment of the present disclosure.
  • a control signal is sent to the plurality of on-off switch modules to turn the plurality of on-off switch modules on or off.
  • the control signal may be a normally open control signal, or a normally closed control signal, or a PWM (Pulse Width Modulation) pulse control signal.
  • the on/off switch module includes: a first fully-controlled semiconductor device 201 and a freewheeling diode 202 connected in anti-parallel thereto, a second fully-controlled semiconductor device 203, and a freewheeling diode 204 and a third thereof connected in anti-parallel thereto
  • the control signal is sent to the on-off switch module, that is, the first fully-controlled semiconductor device 201 and the second fully-controlled semiconductor device 203 to the on/off switch module.
  • the third fully-controlled semiconductor device 205 transmits a control signal.
  • the control signals transmitted to the first fully-controlled semiconductor device 201, the second fully-controlled semiconductor device 203, and the third fully-controlled semiconductor device 205 of one on-off switch module at the same time may be identical.
  • a control signal may be sent to the plurality of on-off switch modules in accordance with an operational state of the modular converter, grid-connected power quality, geographic location, and the like.
  • a first control signal may be sent to the plurality of on/off switch modules to turn off the plurality of on/off switch modules,
  • the confluence path formed between the DC busbars of any two converter modules is disconnected, and the modular converter is in an independent DC bus operating state.
  • the grid-connected power quality of the modular converter does not satisfy a preset condition, for example, when the current harmonic of the modular converter output exceeds a preset threshold, it may be determined that the The DC busbars of several converter modules operate independently.
  • the output current harmonic THDi of the converter is generally measured and designed under full load conditions (generally ⁇ 3%, standard requirement ⁇ 5%).
  • the output current of the converter is small, for example, below 30%, especially At 10% of the power point, the current harmonic THDi output from the converter will increase significantly, exceeding 10%, causing very large pollution to the power grid.
  • the grid-connected power quality of the modular converter does not meet the preset condition, the grid-connected power quality needs to be improved, and the DC bus of the plurality of converter modules is independently operated, and the plurality of converters are
  • the carrier phase shifting technique between the modules can increase the equivalent switching frequency of the modular converter, so that the output voltage waveform of the converter can be closer to the sine wave, when the sine wave of the converter output
  • the harmonics can be basically eliminated, thereby improving the output power quality of the modular converter, and avoiding the influence of poor output power quality on the power grid.
  • the first control signal is sent to the on/off switch module, that is, on and off.
  • the gate set of the first fully-controlled semiconductor device 201 of the switch module, the gate set of the second fully-controlled semiconductor device 203, and the gate set of the third fully-controlled semiconductor device 205 transmit a low-level signal to control the DC bus path disconnection. , to achieve the operation mode of the independent DC bus.
  • a second control signal may be sent to the plurality of on/off switch modules to cause the plurality of on/off switch modules to be both
  • the conduction path is turned on, so that the bus path formed between the DC bus bars of any two converter modules is turned on, and the modular converter is in a parallel DC bus operating state.
  • the modular converter when the modular converter is at the end of the grid, it may be determined that the DC buses of the plurality of converter modules need to be operated in parallel.
  • the modular converter When the modular converter is at the end of the grid, it is required to improve the control response capability of the modular converter, and the DC bus of the plurality of converter modules are operated in parallel, and to the plurality of converters Given the synchronized PWM signal, the parallel operation between the plurality of converter modules can be realized, thereby improving the control response capability of the modular converter and avoiding control oscillation.
  • This PWM signal can be used to control the inverter and/or rectifier.
  • the second control signal is sent to the on/off switch module, that is, on and off.
  • the gate set of the first fully-controlled semiconductor device 201 of the switch module, the gate set of the second fully-controlled semiconductor device 203, and the gate set of the third fully-controlled semiconductor device 205 transmit a high-level signal to control the conduction of the DC bus path. To realize the operation mode of the parallel DC bus.
  • the modular converter when the modular converter is in the parallel DC bus operating state, if any of the converter modules enter the online hot standby state from the operating state, send to the on/off switch module corresponding to the converter module
  • the first control signal disconnects the bus path formed between the DC bus of the converter module and the DC bus of the other converter modules.
  • the online hot standby state is a state in which it is in a standby run and is immediately ready to enter an operating state in response to a running command.
  • the on/off switch module corresponding to the converter module in the online hot standby state is turned off to make the DC bus of the converter module in the online hot standby state and other converters
  • the confluence path formed between the DC busbars of the module is disconnected, so that a loop between the converter module in the online hot standby state and the converter module in the active state can be avoided.
  • the running command can be sent to the converter module, and at the same time, the on/off switch module corresponding to the converter module is turned on.
  • the ability of the modular converter to be in-line hot-swappable also facilitates rapid removal of the failed converter module from the electrical circuit without affecting the normal operation of other converter modules.
  • the gate set and the second fully controlled semiconductor of the first fully controlled semiconductor device 201 of the on/off switch module corresponding to the converter module are The gate set of the device 203 and the gate set of the third fully-controlled semiconductor device 205 transmit a high-level signal to send a low-level signal thereto.
  • the first control signal is sent to the plurality of on/off switch modules to enable any two The confluence path formed between the DC busbars of the converter module is disconnected.
  • the modular converter When the modular converter is in parallel DC bus operation state, one of the converter modules has a short-circuit failure fault, which often causes the entire modular converter to generate short-circuit current at the same time, and the short-circuit current can easily damage the system.
  • Power electronics The prior art usually performs short-circuit protection by adding a DC fuse, but the fuse time of the DC fuse is often in the order of milliseconds (ms), and the DC fuse still has a serious arcing phenomenon. In addition, the fuse is selected. Type and heat dissipation problems are also difficult to solve.
  • the first fully-controlled semiconductor device 201, the second fully-controlled semiconductor device 203, and the third fully-controlled semiconductor device 205 are both IGBTs, and the modular converter is in a parallel DC bus operating state, the converter is in a variable current
  • the current of the converter module flows from its input end (ie, the generator end) and the output end (ie, the power grid end) to the short-circuit point, which makes the corresponding to the converter module
  • the IGBT enters the desaturation region from the saturation amplification region (ie, beyond the saturation amplification region), and the Vce voltage (the voltage between the collector and the emitter) of the IGBT is rapidly increased.
  • the IGBT can quickly detect the short circuit of IGBT and trigger the short circuit protection of IGBT. At present, it can realize the fast IGBT short circuit detection and shutdown operation below 10 microseconds (us), that is, the short circuit current can be cut within 10us. At the same time, after entering the desaturation region, the IGBT will limit the short-circuit current through the IGBT to 4-5 times the rated current of the IGBT. According to an exemplary embodiment of the present disclosure, on one hand, the short-circuit current of the modular converter is limited, and on the other hand, the short-circuit path between the converter modules can be quickly cut off within 10 us, and the non-short-circuit state is ensured. The safety of the power electronics of the module.
  • a PWM pulse control signal having a duty ratio of a specific value may be transmitted to the plurality of on/off switch modules, wherein the specific value is based on The voltage of the DC bus of the plurality of converter modules is determined.
  • the pre-charging process is a process of charging the DC bus in advance to establish a DC voltage.
  • the specific value may be determined based on U max , U min and Z, wherein U max indicates a maximum value among the voltages of the DC bus bars of the plurality of converter modules, U min indicating the plurality of The minimum value among the voltages of the DC bus of the converter module, Z indicates the impedance of the bus circuit formed between the DC bus of the converter module corresponding to U max and the DC bus of the converter module corresponding to U min .
  • the pre-charging speed is fast and slow. If the parallel DC bus is used directly, the pre-charging of the converter module with pre-charging speed will be pre-charged. The circuit is overloaded and will burn the pre-charge circuit in severe cases.
  • the embodiment of the present disclosure realizes that the control effect of multiple converter modules is equivalent to one converter by the parallel bus combined synchronous PWM pulse control technology, ensuring that the open loop gain of the converter control is not affected, and the converter is improved. Control ability.
  • a computer readable storage medium storing a computer program that, when executed by a processor, implements the method of controlling a modular converter as described in the above exemplary embodiments, according to an exemplary embodiment of the present disclosure.
  • a controller includes a processor (not shown) and a memory (not shown), wherein the memory stores a computer program, and when the computer program is executed by the processor, the above example is implemented A method of controlling a modular converter as described in the embodiments.
  • a method of controlling a modular converter according to an exemplary embodiment of the present disclosure may be implemented as computer code in a computer readable recording medium.
  • the computer code can be implemented by those skilled in the art in accordance with the description of the above method.
  • the above method of the present disclosure is implemented when the computer code is executed in a computer.

Abstract

本公开提供一种模块化变流器及其控制方法、风力发电机组。所述模块化变流器包括：多个变流器模块和多个通断开关模块；所述多个变流器模块并联连接，并且与所述多个通断开关模块一一对应，每个变流器模块的直流母线经由对应的通断开关模块相互连接；每个通断开关模块响应于接收到的控制信号导通或关断。

Description

模块化变流器及其控制方法、风力发电机组 技术领域
本公开总体说来涉及变流器技术领域，更具体地讲，涉及一种模块化变流器及其控制方法、一种风力发电机组。
背景技术
模块化变流器采用标准模块化柜体单元，每个柜体单元可独立承担变流器的作用，并可通过相互并联的形式来扩展变流器的容量，以满足不同的发电机的并网输出功率。目前，模块化变流器通常采用独立直流母线的工作方式，即，各个柜体单元的直流母线相互独立，互不影响，相当于各个柜体单元直接并联，这会降低整个变流器的控制响应能力，并可能引发控制振荡。
发明内容
本公开的示例性实施例在于提供一种模块化变流器及其控制方法和风力发电机组，其能够实现模块化变流器的独立直流母线运行状态和并联直流母线运行状态的在线切换，从而实现在线调节模块化变流器的控制增益和并网电能质量。
根据本公开的示例性实施例，提供一种模块化变流器，所述模块化变流器包括：多个变流器模块和多个通断开关模块；所述多个变流器模块并联连接，并且与所述多个通断开关模块一一对应，每个变流器模块的直流母线经由对应的通断开关模块相互连接；每个通断开关模块响应于接收到的控制信号导通或关断；其中，当两个通断开关模块同时导通时，与导通的两个通断开关模块对应的两个变流器模块的直流母线之间形成的汇流路径导通；当一个通断开关模块关断时，与关断的一个通断开关模块对应的变流器模块的直流母线与其他变流器模块的直流母线之间的汇流路径断开。
根据本公开的另一示例性实施例，提供一种控制模块化变流器的方法，所述模块化变流器包括多个变流器模块和多个通断开关模块；所述多个变流器模块并联连接，并且与所述多个通断开关模块一一对应，每个变流器模块 的直流母线经由对应的通断开关模块相互连接；所述方法包括：在所述模块化变流器的运行过程中，向所述多个通断开关模块发送控制信号，以使所述多个通断开关模块导通或关断；其中，当两个通断开关模块同时导通时，与导通的两个通断开关模块对应的两个变流器模块的直流母线之间形成的汇流路径导通；当一个通断开关模块关断时，与关断的一个通断开关模块对应的变流器模块的直流母线与其他变流器模块的直流母线之间的汇流路径断开。
根据本公开的另一示例性实施例，提供一种控制如上所述的模块化变流器的方法，所述方法包括：如果两个变流器模块的直流母线之间的电压不平衡，则控制与存在电压不平衡的两个变流器模块对应的两个通断开关模块同时导通，用于动态调节存在电压不平衡的两个变流器模块的直流母线的电压。
根据本公开的另一示例性实施例，提供一种存储有计算机程序的计算机可读存储介质，当所述计算机程序被处理器执行时实现如上所述的控制模块化变流器的方法。
根据本公开的另一示例性实施例，提供一种控制器，所述控制器包括：处理器；存储器，存储有计算机程序，当所述计算机程序被处理器执行时，实现如上所述的控制模块化变流器的方法。
根据本公开的另一示例性实施例，提供一种风力发电机组，所述风力发电机组包括如上所述的模块化变流器。
根据本公开示例性实施例的模块化变流器及其控制方法和风力发电机组，能够实现模块化变流器的独立直流母线运行状态和并联直流母线运行状态的在线切换，从而实现在线调节模块化变流器的控制增益和并网电能质量。此外，当模块化变流器处于并联直流母线运行状态时，还能够避免处于运行状态的变流器模块与处于在线热备状态的变流器模块之间形成环流；实现变流器模块的直流母线的电压的动态调节；防止在预充电过程中，某个预充电回路充电速度过快造成的过载现象；保证当某一变流器模块发生短路故障时其他变流器模块的电力电子器件的安全。
将在接下来的描述中部分阐述本公开总体构思另外的方面和/或优点，还有一部分通过描述将是清楚的，或者可以经过本公开总体构思的实施而得知。
附图说明
通过下面结合示例性地示出实施例的附图进行的描述，本公开示例性实 施例的上述和其他目的和特点将会变得更加清楚，其中：
图1示出根据本公开的示例性实施例的模块化变流器的结构示意图；
图2示出根据本公开的另一示例性实施例的模块化变流器的结构示意图；
图3示出根据本公开的另一示例性实施例的模块化变流器的结构示意图；
图4示出根据本公开的示例性实施例的任意两个变流器模块的直流母线之间的汇流方式的示意图；
图5示出根据本公开的示例性实施例的控制模块化变流器的方法的流程图。
具体实施方式
现将详细参照本公开的实施例，所述实施例的示例在附图中示出，其中，相同的标号始终指的是相同的部件。以下将通过参照附图来说明所述实施例，以便解释本公开。
图1示出根据本公开的示例性实施例的模块化变流器的结构示意图。
如图1所示，根据本公开的示例性实施例的模块化变流器包括：N个变流器模块(例如，10-1、10-2、…、10-n)和N个通断开关模块(例如，20-1、20-2、…、20-n)，其中，N为大于1的整数。这里，模块化变流器采用模块化结构，每个变流器模块能够独立承担变流器的作用，也即，每个变流器模块能够独立实现变流器的功能。应该理解，图1所示的变流器模块的电路结构仅作为示例，变流器模块的电路结构不限于此。
具体说来，N个变流器模块相互并联，N个变流器模块与N个通断开关模块一一对应，每个变流器模块的直流母线经由对应的通断开关模块相互连接。
换言之，针对任意两个变流器模块，其中一个变流器模块的直流母线依次经由与所述一个变流器模块对应的通断开关模块和与另一个变流器模块对应的通断开关模块连接到所述另一个变流器模块的直流母线。
每个通断开关模块响应于接收到的控制信号导通或关断，其中，当两个通断开关模块同时导通时，与导通的两个通断开关模块对应的两个变流器模块的直流母线之间形成的汇流路径导通；当一个通断开关模块关断时，与关断的一个通断开关模块对应的变流器模块的直流母线与其他变流器模块的直流母线之间形成的汇流路径断开。
作为示例，每一个变流器模块可被单独地形成为一个柜体单元。
应该理解，N个变流器模块相互并联，即，N个变流器模块的输入端相互连接，并且N个变流器模块的输出端相互连接。作为示例，N个变流器模块的输入端可均经由框架断路器连接到发电机的输出端，N个变流器模块的输出端可均经由另一框架断路器连接到电网侧变压器的输入端。
作为示例，模块化变流器可为三电平变流器或两电平变流器。如果模块化变流器为三电平变流器，则每个变流器模块具有直流正母线(DC+)、直流负母线(DC-)、以及直流中性母线(NP)，相应地，N个变流器模块的直流正母线经由对应的通断开关模块相互连接，N个变流器模块的直流负母线经由对应的通断开关模块相互连接，并且，N个变流器模块的直流中性母线经由对应的通断开关模块相互连接。如果模块化变流器为两电平变流器，则每个变流器模块仅具有直流正母线和直流负母线，相应地，N个变流器模块的直流正母线经由对应的通断开关模块相互连接，并且，N个变流器模块的直流负母线经由对应的通断开关模块相互连接。
图2示出根据本公开的另一示例性实施例的模块化变流器的结构示意图。这里，模块化变流器为三电平变流器。应该理解，图2所示的变流器模块的电路结构仅作为示例，变流器模块的电路结构不限于此。例如，作为另一示例，变流器模块的电路结构可如图3所示。
如图2所示，通断开关模块包括：第一全控型半导体器件201及与其反向并联的续流二极管202、第二全控型半导体器件203及与其反向并联的续流二极管204、第三全控型半导体器件205及与其反向并联的续流二极管206。
具体说来，第一全控型半导体器件201的集电极连接到对应的变流器模块的直流正母线，所有第一全控型半导体器件201的发射极相互连接；第二全控型半导体器件203的集电极连接到对应的变流器模块的直流中性母线，所有第二全控型半导体器件203的发射极相互连接；第三全控型半导体器件205的集电极连接到对应的变流器模块的直流负母线，所有第三全控型半导体器件205的发射极相互连接。
应该理解，可通过各种适当的方式来实现所有第一全控型半导体器件201的发射极相互连接、所有第二全控型半导体器件203的发射极相互连接、所有第三全控型半导体器件205的发射极相互连接。
例如，如图2所示，根据本公开的另一示例性实施例的模块化变流器还 可包括：第一直流汇流母线30、第二直流汇流母线40和第三直流汇流母线50，具体地，所有第一全控型半导体器件201的发射极均连接到第一直流汇流母线30，以使所有第一全控型半导体器件201的发射极经由第一直流汇流母线30相互连接；所有第二全控型半导体器件203的发射极均连接到第二直流汇流母线40，以使所有第二全控型半导体器件203的发射极经由第二直流汇流母线40相互连接；所有第三全控型半导体器件205的发射极均连接到第三直流汇流母线50，以使所有第三全控型半导体器件205的发射极经由第三直流汇流母线50相互连接。
相应地，通断开关模块接收控制信号，实质是通断开关模块的第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205接收控制信号。
作为示例，一个通断开关模块的第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205在同一时间接收到的控制信号可相同。
作为示例，第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205可为同一类型的全控型半导体器件。
作为示例，第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205可均为绝缘栅双极型晶体管(IGBT，Insulated Gate Bipolar Transistor)，或者均为电力场效应晶体管(Power MOSFET)，或者均为集成门极换流晶闸管(IGCT，Integrated Gate Commutated Thyristors)。
此外，作为示例，当所述模块化变流器为两电平变流器时，通断开关模块可包括：第四全控型半导体器件(未示出)及与其反向并联的续流二极管(未示出)、第五全控型半导体器件(未示出)及与其反向并联的续流二极管(未示出)。具体说来，第四全控型半导体器件的集电极连接到对应的变流器模块的直流正母线，所有第四全控型半导体器件的发射极相互连接；第五全控型半导体器件的集电极连接到对应的变流器模块的直流负母线，所有第五全控型半导体器件的发射极相互连接。进一步地，作为示例，第四全控型半导体器件和第五全控型半导体器件可均为绝缘栅双极型晶体管，或者均为电力场效应晶体管，或者均为集成门极换流晶闸管。
图4示出根据本公开的示例性实施例的任意两个变流器模块的直流母线之间的汇流方式的示意图。本示例中，模块化变流器为三电平变流器，通断 开关模块包括：第一全控型半导体器件201及与其反向并联的续流二极管202、第二全控型半导体器件203及与其反向并联的续流二极管204、第三全控型半导体器件205及与其反向并联的续流二极管206。
在一个示例中，如果两个变流器模块的直流母线之间的电压不平衡，则控制与存在电压不平衡的两个变流器模块对应的两个通断开关模块同时导通，用于动态调节存在电压不平衡的两个变流器模块的直流母线的电压。
在一个示例中，两个变流器模块的直流母线之间的电压不平衡的情况，例如可以是：第一变流器模块的直流正母线与直流中性母线之间的电压高于第二变流器模块的直流正母线与直流中性母线之间的电压；或者，第一变流器模块的直流中性母线与直流负母线之间的电压高于第二变流器模块的直流中性母线与直流负母线之间的电压；或者，第一变流器模块的直流正母线与直流负母线之间的电压高于第二变流器模块的直流正母线与直流负母线之间的电压。
如图4所示，以变流器模块10-1和变流器模块10-2为例，变流器模块10-1与通断开关模块20-1对应，变流器模块10-2与通断开关模块20-2对应。当通断开关模块20-1和通断开关模块20-2均导通(例如，分别向第一全控型半导体器件201的门集、第二全控型半导体器件203的门集或者第三全控型半导体器件205的门集发送高电平信号)时，能够实现变流器模块10-1和变流器模块10-2的直流母线的电压的动态调节。
在下文中，为了便于说明，第一变流器模块表示变流器模块10-1，第二变流器模块表示变流器模块10-2。第一通断开关模块表示通断开关模块20-1，第二通断开关模块表示通断开关模块20-2。
作为示例，如果第一变流器模块的直流正母线与直流中性母线之间的电压高于第二变流器模块的直流正母线与直流中性母线之间的电压，则与第一变流器模块对应的第一通断开关模块的第一全控型半导体器件导通，且，与第二变流器模块对应的第二通断开关模块的第二全控型半导体器件导通，从而构成从第一变流器模块的直流正母线到第二变流器模块的直流正母线的汇流回路，并且，构成从第二变流器模块的直流中性母线到第一变流器模块的直流中性母线的汇流回路。
具体说来，如果变流器模块10-1的DC+与NP之间的电压高于变流器模块10-2的DC+与NP之间的电压，则控制通断开关模块20-1的第一全控型半 导体器件201导通，同时，控制通断开关模块20-2的第二全控型半导体器件203的导通，从而形成从变流器模块10-1的DC+依次经由通断开关模块20-1的第一全控型半导体器件201和通断开关模块20-2的续流二极管202到变流器模块10-2的DC+、且从变流器模块10-2的NP依次经由通断开关模块20-2的第二全控型半导体器件203和通断开关模块20-1的续流二极管204到变流器模块10-1的NP的汇流回路。
如果变流器模块10-1的DC+与NP之间的电压低于变流器模块10-2的DC+与NP之间的电压，则控制通断开关模块20-2的第一全控型半导体器件201导通，同时，控制通断开关模块20-1的第二全控型半导体器件203导通，从而形成从变流器模块10-2的DC+依次经由通断开关模块20-2的第一全控型半导体器件201和通断开关模块20-1的续流二极管202到变流器模块10-1的DC+、且从变流器模块10-1的NP依次经由通断开关模块20-1的第二全控型半导体器件203和通断开关模块20-2的续流二极管204到变流器模块10-2的NP的汇流回路。
作为示例，如果第一变流器模块的直流中性母线与直流负母线之间的电压高于第二变流器模块的直流中性母线与直流负母线之间的电压，则与第一变流器模块对应的第一通断开关模块的第二全控型半导体器件导通，且，与第二变流器模块对应的第二通断开关模块的第三全控型半导体器件导通，从而构成从第一变流器模块的直流中性母线到第二变流器模块的直流中性母线的汇流回路，并且，构成从第二变流器模块的直流负母线到第一变流器模块的直流负母线的汇流回路。
具体说来，如果变流器模块10-1的NP与DC-之间的电压高于变流器模块10-2的NP与DC-之间的电压，则控制通断开关模块20-1的第二全控型半导体器件203导通，同时，控制通断开关模块20-2的第三全控型半导体器件205导通，从而形成从变流器模块10-1的NP依次经由通断开关模块20-1的第二全控型半导体器件203和通断开关模块20-2的续流二极管204到变流器模块10-2的NP、且从变流器模块10-2的DC-依次经由通断开关模块20-2的第三全控型半导体器件205和通断开关模块20-1的续流二极管206到变流器模块10-1的DC-的汇流回路。
如果变流器模块10-1的NP与DC-之间的电压低于变流器模块10-2的NP与DC-之间的电压，则控制通断开关模块20-2的第二全控型半导体器件 203导通，同时，控制通断开关模块20-1的第三全控型半导体器件205导通，从而形成从变流器模块10-2的NP依次经由通断开关模块20-2的第二全控型半导体器件203和通断开关模块20-1的续流二极管204到变流器模块10-1的NP、且从变流器模块10-1的DC-依次经由通断开关模块20-1的第二全控型半导体器件205和通断开关模块20-2的续流二极管206到变流器模块10-2的DC-的汇流回路。
作为示例，如果第一变流器模块的直流正母线与直流负母线之间的电压高于第二变流器模块的直流正母线与直流负母线之间的电压，则与第一变流器模块对应的第一通断开关模块的第一全控型半导体器件导通，且，与第二变流器模块对应的第二通断开关模块的第三全控型半导体器件导通，从而构成从第一变流器模块的直流正母线到第二变流器模块的直流正母线的汇流回路，并且，构成从第二变流器模块的直流负母线到第一变流器模块的直流负母线的汇流回路。
具体说来，如果变流器模块10-1的直流正母线和直流负母线之间的电压差(即，DC+与DC-之间的电压差)高于变流器模块10-2的直流正母线和直流负母线之间的电压差，则控制通断开关模块20-1的第一全控型半导体器件201导通，同时，控制通断开关模块20-2的第三全控型半导体器件205导通，从而形成从变流器模块10-1的DC+依次经由通断开关模块20-1的第一全控型半导体器件201和通断开关模块20-2的续流二极管202到变流器模块10-2的DC+、且从变流器模块10-2的DC-依次经由通断开关模块20-2的第三全控型半导体器件205和通断开关模块20-1的续流二极管206到变流器模块10-1的DC-的汇流回路。
如果变流器模块10-1的直流正母线和直流负母线之间的电压差低于变流器模块10-2的直流正母线和直流负母线之间的电压差，则控制通断开关模块20-2的第一全控型半导体器件201导通，同时，控制通断开关模块20-1的第三全控型半导体器件205导通，从而形成从变流器模块10-2的DC+依次经由通断开关模块20-2的第一全控型半导体器件201和通断开关模块20-1的续流二极管202到变流器模块10-1的DC+、且从变流器模块10-1的DC-依次经由通断开关模块20-1的第三全控型半导体器件205和通断开关模块20-2的续流二极管206到变流器模块10-2的DC-的汇流回路。
根据本公开的示例性实施例的风力发电机组包括：上述示例性实施例所 述的模块化变流器。作为示例，所述模块化变流器的输入端(也即，每个变流器模块的输入端)可经由框架断路器连接到发电机的输出端。
图5示出根据本公开的示例性实施例的控制模块化变流器的方法的流程图。
参照图5，在步骤S10，在所述模块化变流器的运行过程中，向所述多个通断开关模块发送控制信号，以使所述多个通断开关模块导通或关断。作为示例，所述控制信号可以是常开控制信号、或者常闭控制信号、或者PWM(脉冲宽度调制)脉冲控制信号。
作为示例，当通断开关模块包括：第一全控型半导体器件201及与其反向并联的续流二极管202、第二全控型半导体器件203及与其反向并联的续流二极管204、第三全控型半导体器件205及与其反向并联的续流二极管206时，向通断开关模块发送控制信号即向通断开关模块的第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205发送控制信号。作为示例，同一时间向一个通断开关模块的第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205发送的控制信号可完全相同。
作为示例，可根据所述模块化变流器的运行状态、并网电能质量、地理位置等来向所述多个通断开关模块发送控制信号。
作为示例，当确定需要使所述多个变流器模块的直流母线独立运行时，可向所述多个通断开关模块发送第一控制信号以使所述多个通断开关模块关断，从而任意两个变流器模块的直流母线之间形成的汇流路径断开，所述模块化变流器处于独立直流母线运行状态。
作为示例，当所述模块化变流器的并网电能质量不满足预设条件时，例如，当所述模块化变流器输出的电流谐波超出预设阈值时，可确定需要使所述多个变流器模块的直流母线独立运行。
变流器的输出电流谐波THDi一般是在满载条件下测量及设计的(一般<3％，标准要求<5％)，当变流器输出的电流较小，例如在30％以下时，尤其是在10％的功率点，变流器输出的电流谐波THDi会显著增大，会超过10％，对电网造成非常大的污染。
当所述模块化变流器的并网电能质量不满足预设条件时，需要提升并网电能质量，使所述多个变流器模块的直流母线独立运行，并通过所述多个变 流器模块之间的载波移相技术，即可提升所述模块化变流器的等效开关频率，可以使变流器的输出电压波形更加逼近于正弦波，当变流器输出的正弦波和电网的正弦波基本一致时，可基本消除谐波，进而提升所述模块化变流器的输出电能质量，避免输出电能质量差对电网造成影响。
作为示例，当第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205均为IGBT时，向通断开关模块发送第一控制信号，即向通断开关模块的第一全控型半导体器件201的门集、第二全控型半导体器件203的门集以及第三全控型半导体器件205的门集发送低电平信号，控制直流汇流路径断开，实现独立直流母线的运行方式。
作为另一示例，当确定需要使所述多个变流器模块的直流母线并联运行时，可向所述多个通断开关模块发送第二控制信号以使所述多个通断开关模块均导通，从而任意两个变流器模块的直流母线之间形成的汇流路径导通，所述模块化变流器处于并联直流母线运行状态。
作为示例，当所述模块化变流器处于电网末端时，可确定需要使所述多个变流器模块的直流母线并联运行。当所述模块化变流器处于电网末端时，需要提高所述模块化变流器的控制响应能力，使所述多个变流器模块的直流母线并联运行，并向所述多个变流器模块给定同步的PWM信号，即可实现所述多个变流器模块之间的并联运行，进而提升所述模块化变流器的控制响应能力，避免控制振荡。该PWM信号可以用于控制逆变器和/或整流器。
作为示例，当第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205均为IGBT时，向通断开关模块发送第二控制信号，即向通断开关模块的第一全控型半导体器件201的门集、第二全控型半导体器件203的门集以及第三全控型半导体器件205的门集发送高电平信号，控制直流汇流路径导通，实现并联直流母线的运行方式。
作为示例，当所述模块化变流器处于并联直流母线运行状态时，如果任一变流器模块由运行状态进入在线热备状态，则向与该变流器模块对应的通断开关模块发送第一控制信号，以使该变流器模块的直流母线与其他变流器模块的直流母线之间形成的汇流路径断开。这里，在线热备状态即处于待机状态(ready run)且随时能够响应于运行指令立即进入运行状态的状态。
当所述模块化变流器的输出功率较低时，为了提高所述模块化变流器的使用寿命，可使其中部分变流器模块切出运行状态处于在线热备状态，然而， 处于在线热备状态的变流器模块与处于工作状态的变流器模块之间会产生环流。根据本公开的示例性实施例，令与处于在线热备状态的变流器模块对应的通断开关模块关断，以使处于在线热备状态的变流器模块的直流母线与其他变流器模块的直流母线之间形成的汇流路径断开，从而能够避免处于在线热备状态的变流器模块与处于工作状态的变流器模块之间产生环流。当需要处于在线热备状态的变流器模块恢复运行状态时，可向该变流器模块发送运行指令，并同时令与该变流器模块对应的通断开关模块导通。此外，所述模块化变流器在线热备的能力也便于快速地从电气回路上切除发生故障的变流器模块，而不影响其它变流器模块的正常工作。
作为示例，当第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205均为IGBT，且所述模块化变流器处于并联直流母线运行状态时，如果任一变流器模块由运行状态进入在线热备状态，则由向与该变流器模块对应的通断开关模块的第一全控型半导体器件201的门集、第二全控型半导体器件203的门集以及第三全控型半导体器件205的门集发送高电平信号变为向其发送低电平信号。
作为示例，当所述模块化变流器处于并联直流母线运行状态时，如果检测到任一通断开关模块短路，则向所述多个通断开关模块发送第一控制信号，以使任意两个变流器模块的直流母线之间形成的汇流路径断开。
当所述模块化变流器处于并联直流母线运行状态时，其中一个变流器模块发生短路失效故障，往往会造成整个模块化变流器同时产生短路电流，而短路电流会轻易地破坏系统中的电力电子器件。现有技术通常通过加装直流熔断器的方法来进行短路保护，但是直流熔断器的熔断时间往往在毫秒级(ms)，且直流熔断器还存在较严重的拉弧现象，此外，熔断器选型和散热问题也难以解决。
当第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205均为IGBT，且所述模块化变流器处于并联直流母线运行状态时，在变流器模块产生短路电流的瞬间，该变流器模块的电流会从其输入端(即，发电机端)和输出端(即，电网端)流向短路点，这使得与该变流器模块对应的IGBT由饱和放大区进入到退饱和区(即，超出饱和放大区)，该IGBT的Vce电压(集电极与发射极之间的电压)迅速提升，因此，通过对IGBT的Vce电压的监测，即可快速地检测到IGBT的短路现象，并触发 IGBT的短路保护，目前能够实现10微秒(us)以下的快速IGBT短路检测及关断动作，即10us以内可以实现短路电流的切断动作。同时IGBT在进入退饱和区后，会限制通过IGBT的短路电流在4-5倍的IGBT额定电流。根据本公开的示例性实施例，一方面限制了模块化变流器的短路电流，另外一方面能够在10us以内快速地切除变流器模块之间的短路路径，保证了非短路状态的变流器模块的电力电子器件的安全。
作为示例，在对所述多个变流器模块进行预充电的过程中，可向所述多个通断开关模块发送占空比为特定值的PWM脉冲控制信号，其中，所述特定值基于所述多个变流器模块的直流母线的电压被确定。这里，预充电的过程即提前对直流母线进行充电，建立直流电压的过程。
优选地，所述特定值可基于U max、U min和Z被确定，其中，U max指示所述多个变流器模块的直流母线的电压之中的最大值，U min指示所述多个变流器模块的直流母线的电压之中的最小值，Z指示U max所对应的变流器模块的直流母线与U min所对应的变流器模块的直流母线之间形成的汇流回路的阻抗。
在预充电的过程中，由于各变流器模块参数的不一致，导致预充电速度有快有慢，如果直接采用并联直流母线的方式，会造成预充电速度过快的变流器模块的预充电回路过负荷，严重时会烧毁预充电回路。作为示例，当第一全控型半导体器件201、第二全控型半导体器件203以及第三全控型半导体器件205均为IGBT时，通过IGBT的电流为I＝α*(U max-U min)/Z，其中，α为PWM脉冲控制信号的占空比，因此，当预充电过程中不同变流器模块的直流母线之间的电压差值过大时，可减小占空比α，以减小直流汇流回路的电流，从而防止预充电过程中单个预充电回路充电速度过快造成的过载现象。
本公开的实施例通过并联母线合并同步PWM脉冲控制技术，实现多个变流器模块的控制效果等同于一个变流器，保证变流器的控制的开环增益不受影响，提高变流器的控制能力。
根据本公开的示例性实施例的存储有计算机程序的计算机可读存储介质，当所述计算机程序被处理器执行时实现上述示例性实施例所述的控制模块化变流器的方法。
根据本公开的示例性实施例的控制器包括：处理器(未示出)和存储器(未示出)，其中，存储器存储有计算机程序，当所述计算机程序被处理器执 行时，实现上述示例性实施例所述的控制模块化变流器的方法。
此外，根据本公开示例性实施例的控制模块化变流器的方法可以被实现为计算机可读记录介质中的计算机代码。本领域技术人员可以根据对上述方法的描述来实现所述计算机代码。当所述计算机代码在计算机中被执行时实现本公开的上述方法。
虽然已表示和描述了本公开的一些示例性实施例，但本领域技术人员应该理解，在不脱离由权利要求及其等同物限定其范围的本公开的原理和精神的情况下，可以对这些实施例进行修改。

Claims (21)

  1. 一种模块化变流器，其特征在于，包括：多个变流器模块和多个通断开关模块；
    所述多个变流器模块并联连接，并且与所述多个通断开关模块一一对应，每个变流器模块的直流母线经由对应的通断开关模块相互连接；
    每个通断开关模块响应于接收到的控制信号导通或关断；其中，
    当两个通断开关模块同时导通时，与导通的两个通断开关模块对应的两个变流器模块的直流母线之间形成的汇流路径导通；
    当一个通断开关模块关断时，与关断的一个通断开关模块对应的变流器模块的直流母线与其他变流器模块的直流母线之间的汇流路径断开。
  2. 根据权利要求1所述的模块化变流器，其特征在于，所述变流器模块具有直流正母线和直流负母线；
    所述变流器模块的直流正母线通过对应的通断开关模块相互连接，所述变流器模块的直流负母线通过对应的通断开关模块相互连接。
  3. 根据权利要求2所述的模块化变流器，其特征在于，所述变流器模块还具有直流中性母线，所述变流器模块的直流中性母线通过对应的通断开关模块相互连接。
  4. 根据权利要求3所述的模块化变流器，其特征在于，当两个通断开关模块同时导通时，与导通的两个通断开关模块对应的两个变流器模块的直流母线之间形成的汇流路径导通，用于动态调节与导通的两个通断开关模块对应的两个变流器模块的直流母线之间的电压。
  5. 根据权利要求4所述的模块化变流器，其特征在于，所述模块化变流器为三电平变流器；
    所述通断开关模块包括：第一全控型半导体器件及与其反向并联的续流二极管、第二全控型半导体器件及与其反向并联的续流二极管、第三全控型半导体器件及与其反向并联的续流二极管；其中，
    第一全控型半导体器件的集电极连接到对应的变流器模块的直流正母线，第一全控型半导体器件的发射极连接至第一直流汇流母线；
    第二全控型半导体器件的集电极连接到对应的变流器模块的直流中性母线，第二全控型半导体器件的发射极连接至第二直流汇流母线；
    第三全控型半导体器件的集电极连接到对应的变流器模块的直流负母线，第三全控型半导体器件的发射极连接至第三直流汇流母线。
  6. 根据权利要求2所述的模块化变流器，其特征在于，所述模块化变流器为两电平变流器；
    所述通断开关模块包括：第四全控型半导体器件及与其反向并联的续流二极管、第五全控型半导体器件及与其反向并联的续流二极管；其中，
    第四全控型半导体器件的集电极连接到对应的变流器模块的直流正母线，第四全控型半导体器件的发射极相互连接；
    第五全控型半导体器件的集电极连接到对应的变流器模块的直流负母线，第五全控型半导体器件的发射极相互连接。
  7. 根据权利要求5所述的模块化变流器，其特征在于，
    如果第一变流器模块的直流正母线与直流中性母线之间的电压高于第二变流器模块的直流正母线与直流中性母线之间的电压，则
    与第一变流器模块对应的第一通断开关模块的第一全控型半导体器件导通，且，与第二变流器模块对应的第二通断开关模块的第二全控型半导体器件导通，
    从而构成从第一变流器模块的直流正母线到第二变流器模块的直流正母线的汇流回路，并且，构成从第二变流器模块的直流中性母线到第一变流器模块的直流中性母线的汇流回路。
  8. 根据权利要求5所述的模块化变流器，其特征在于，
    如果第一变流器模块的直流中性母线与直流负母线之间的电压高于第二变流器模块的直流中性母线与直流负母线之间的电压，则
    与第一变流器模块对应的第一通断开关模块的第二全控型半导体器件导通，且，与第二变流器模块对应的第二通断开关模块的第三全控型半导体器件导通，
    从而构成从第一变流器模块的直流中性母线到第二变流器模块的直流中性母线的汇流回路，并且，构成从第二变流器模块的直流负母线到第一变流器模块的直流负母线的汇流回路。
  9. 根据权利要求5所述的模块化变流器，其特征在于，
    如果第一变流器模块的直流正母线与直流负母线之间的电压高于第二变流器模块的直流正母线与直流负母线之间的电压，则
    与第一变流器模块对应的第一通断开关模块的第一全控型半导体器件导通，且，与第二变流器模块对应的第二通断开关模块的第三全控型半导体器件导通，
    从而构成从第一变流器模块的直流正母线到第二变流器模块的直流正母线的汇流回路，并且，构成从第二变流器模块的直流负母线到第一变流器模块的直流负母线的汇流回路。
  10. 一种控制模块化变流器的方法，其特征在于，所述模块化变流器包括多个变流器模块和多个通断开关模块；
    所述多个变流器模块并联连接，并且与所述多个通断开关模块一一对应，每个变流器模块的直流母线经由对应的通断开关模块相互连接；
    所述方法包括：
    在所述模块化变流器的运行过程中，向所述多个通断开关模块发送控制信号，以使所述多个通断开关模块导通或关断；其中，
    当两个通断开关模块同时导通时，与导通的两个通断开关模块对应的两个变流器模块的直流母线之间形成的汇流路径导通；
    当一个通断开关模块关断时，与关断的一个通断开关模块对应的变流器模块的直流母线与其他变流器模块的直流母线之间的汇流路径断开。
  11. 根据权利要求10所述的方法，其特征在于，向所述多个通断开关模块发送控制信号的步骤包括：
    当确定需要使所述多个变流器模块的直流母线独立运行时，向所述多个通断开关模块发送第一控制信号以使所述多个通断开关模块关断，从而所述模块化变流器处于独立直流母线运行状态；
    当确定需要使所述多个变流器模块的直流母线并联运行时，向所述多个通断开关模块发送第二控制信号以使所述多个通断开关模块均导通，从而所述模块化变流器处于并联直流母线运行状态。
  12. 根据权利要求11所述的方法，其特征在于，
    当所述模块化变流器输出的电流谐波不满足预设条件时，确定需要使所述多个变流器模块的直流母线独立运行；
    和/或，当所述模块化变流器处于电网末端时，确定需要使所述多个变流器模块的直流母线并联运行。
  13. 根据权利要求11所述的方法，其特征在于，向所述多个通断开关模 块发送控制信号的步骤包括：
    当所述模块化变流器处于并联直流母线运行状态时，如果任一变流器模块由运行状态进入在线热备状态，则向与所述任一变流器模块对应的通断开关模块发送第一控制信号；
    和/或，当所述模块化变流器处于并联直流母线运行状态时，如果检测到任一通断开关模块短路，则向所述多个通断开关模块发送第一控制信号。
  14. 根据权利要求10所述的方法，其特征在于，向所述多个通断开关模块发送控制信号的步骤包括：
    在对所述多个变流器模块进行预充电的过程中，向所述多个通断开关模块发送占空比为特定值的PWM脉冲控制信号，
    其中，所述特定值基于所述多个变流器模块的直流母线的电压被确定。
  15. 一种控制如权利要求5所述的模块化变流器的方法，其特征在于，所述方法包括：
    如果两个变流器模块的直流母线之间的电压不平衡，则控制与存在电压不平衡的两个变流器模块对应的两个通断开关模块同时导通，用于动态调节存在电压不平衡的两个变流器模块的直流母线的电压。
  16. 根据权利要求15所述的方法，其特征在于，所述方法包括：
    如果第一变流器模块的直流正母线与直流中性母线之间的电压高于第二变流器模块的直流正母线与直流中性母线之间的电压，则
    控制与第一变流器模块对应的第一通断开关模块的第一全控型半导体器件导通，且，控制与第二变流器模块对应的第二通断开关模块的第二全控型半导体器件导通。
  17. 根据权利要求15所述的方法，其特征在于，所述方法包括：
    如果第一变流器模块的直流中性母线与直流负母线之间的电压高于第二变流器模块的直流中性母线与直流负母线之间的电压，则
    控制与第一变流器模块对应的第一通断开关模块的第二全控型半导体器件导通，且，控制与第二变流器模块对应的第二通断开关模块的第三全控型半导体器件导通。
  18. 根据权利要求15所述的方法，其特征在于，所述方法还包括：
    如果第一变流器模块的直流正母线与直流负母线之间的电压高于第二变流器模块的直流正母线与直流负母线之间的电压，则
    控制与第一变流器模块对应的第一通断开关模块的第一全控型半导体器件导通，且，控制与第二变流器模块对应的第二通断开关模块的第三全控型半导体器件导通。
  19. 一种存储有计算机程序的计算机可读存储介质，其特征在于，当所述计算机程序被处理器执行时实现如权利要求10至18中的任意一项所述的控制模块化变流器的方法。
  20. 一种控制器，其特征在于，所述控制器包括：
    处理器；
    存储器，存储有计算机程序，当所述计算机程序被处理器执行时，实现如权利要求10至18中的任意一项所述的控制模块化变流器的方法。
  21. 一种风力发电机组，其特征在于，所述风力发电机组包括如权利要求1至9中的任意一项所述的模块化变流器。
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