WO2021212987A1 - 一种模块式直流耗能装置故障冗余控制方法 - Google Patents

一种模块式直流耗能装置故障冗余控制方法 Download PDF

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Publication number
WO2021212987A1
WO2021212987A1 PCT/CN2021/077004 CN2021077004W WO2021212987A1 WO 2021212987 A1 WO2021212987 A1 WO 2021212987A1 CN 2021077004 W CN2021077004 W CN 2021077004W WO 2021212987 A1 WO2021212987 A1 WO 2021212987A1
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Prior art keywords
sub
module
modules
control system
modular
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PCT/CN2021/077004
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English (en)
French (fr)
Inventor
谢晔源
王宇
李海英
曹冬明
姚宏洋
李汉杰
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南京南瑞继保电气有限公司
南京南瑞继保工程技术有限公司
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Priority to DE112021000163.9T priority Critical patent/DE112021000163T5/de
Publication of WO2021212987A1 publication Critical patent/WO2021212987A1/zh

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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/045—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage adapted to a particular application and not provided for elsewhere
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
    • H02H3/02—Details
    • H02H3/05—Details with means for increasing reliability, e.g. redundancy arrangements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/26—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured
    • H02H7/268—Sectionalised protection of cable or line systems, e.g. for disconnecting a section on which a short-circuit, earth fault, or arc discharge has occured for dc systems

Definitions

  • This application relates to the field of power electronics technology, and in particular to a failure redundancy control method of a modular DC energy consumption device.
  • DC energy consuming devices usually adopt a modular approach. Once a module fails, in order to ensure the reliability of the energy consuming device, the prior art approach bypasses the failed module. When the number of module bypasses exceeds a certain value, the energy-consuming device will stop operating for its own safety and lose its energy-consuming capacity. At this time, the inverter will face a sudden increase in DC voltage, which will cause the inverter to be locked out of operation and cause an impact on the power grid. Excessive DC voltage can also cause damage to the sub-modules of the converter, causing serious consequences. It is difficult to balance the reliability of the inverter and the reliability of the DC energy consuming device. Therefore, it is necessary to coordinate and trade-off between the reliability of the converter and the reliability of the DC energy consuming device, so as to improve the reliability of the entire system as the ultimate goal.
  • This application aims to provide a failure redundancy control method for a modular DC energy consumption device.
  • An embodiment of the present application provides a failure redundancy control method for a modular DC energy consuming device.
  • the modular DC energy consuming device is composed of multiple sub-modules connected in series, and the control method includes: cumulative failure sub-modules Number; determine the redundancy mode level according to the number of failed sub-modules, and enter the corresponding redundancy mode; at least one of the redundancy modes includes when the number of failed sub-modules reaches the upper threshold of the current redundancy mode, jump out of the current redundancy mode, and Automatically enter a higher level of redundancy mode.
  • the modular DC energy consumption device may be composed of M sub-modules in series, where M is an integer greater than or equal to 2; the modular DC energy consumption device further includes an energy dissipation resistor, and the energy dissipation resistor is connected to the M
  • the sub-modules are connected in series or/and distributed in each sub-module; the sub-module includes a capacitor, a power semiconductor device and a bypass switch, and the turning on and off of the power semiconductor device controls the input and Exit; the sub-module is short-circuited after the bypass switch is closed;
  • the modular DC energy consumption device further includes a main control system and a sub-module control system, the sub-module includes the sub-module control system, the The main control system communicates with the sub-module control system downwards, and communicates with the external control system on the upper side; also includes a main control system and a sub-module control system, the main control system controls the standby state with the sub-module downwards ,
  • multiple redundancy mode settings and switching control are used to balance the reliability of the system and the reliability of the energy consuming device.
  • the present invention sets the redundancy mode of the DC energy consuming device hierarchically, and switches the redundancy mode according to the number of sub-modules that have failed. As the number of levels of the redundancy mode increases, the performance of the corresponding device continues to deteriorate, based on this To perform different processing methods, and feedback the status of the device to the controller of the converter in real time.
  • the hierarchical processing method is that the redundancy of the sub-modules of the energy-consuming device is fully utilized, and the reliability of the device is taken into account with the system. Reliability.
  • the invention categorizes the faults of the sub-modules of the DC energy consuming device, utilizes the sub-module control system to control the DC voltage automatically under the communication failure, and makes full use of the energy consuming capacity of the device.
  • Fig. 1 shows a schematic flow chart of a control method of a modular DC energy consuming device according to an embodiment of the present application.
  • Fig. 2 shows a schematic diagram of an application scenario of the method shown in Fig. 1.
  • FIG. 3 shows a schematic diagram of the topological structure of the modular DC energy consumption device involved in the method shown in FIG. 1.
  • 4A-4D show schematic diagrams of the sub-modules of the modular DC energy consumption device shown in FIG. 3.
  • FIG. 5 shows a schematic flowchart of a control method of a modular DC energy consuming device according to another embodiment of the present application.
  • FIG. 6 shows a schematic flow diagram of the unfolding steps of S120 in the method shown in FIG. 5.
  • FIG. 7 shows a schematic flow diagram of the primary redundancy mode in the method shown in FIG. 5.
  • FIG. 8 shows a schematic flowchart of the secondary redundancy mode in the method shown in FIG. 5.
  • FIG. 9 shows a schematic flowchart of the three-level redundancy mode in the method shown in FIG. 5.
  • FIG. 10 shows a schematic flowchart of the four-level redundancy mode in the method shown in FIG. 5.
  • This application aims to provide a failure redundancy control method for a modular DC energy consumption device.
  • An embodiment of the present application provides a failure redundancy control method for a modular DC energy consuming device.
  • the modular DC energy consuming device is composed of multiple sub-modules connected in series, and the control method includes: cumulative failure sub-modules Number; determine the redundancy mode level according to the number of failed sub-modules, and enter the corresponding redundancy mode; at least one of the redundancy modes includes when the number of failed sub-modules reaches the upper threshold of the current redundancy mode, jump out of the current redundancy mode, and Automatically enter a higher level of redundancy mode.
  • the modular DC energy consumption device may be composed of M sub-modules in series, where M is an integer greater than or equal to 2; the modular DC energy consumption device further includes an energy dissipation resistor, and the energy dissipation resistor is connected to the M
  • the sub-modules are connected in series or/and distributed in each sub-module; the sub-module includes a capacitor, a power semiconductor device and a bypass switch, and the turning on and off of the power semiconductor device controls the input and Exit; the sub-module is short-circuited after the bypass switch is closed;
  • the modular DC energy consumption device further includes a main control system and a sub-module control system, the sub-module includes the sub-module control system, the The main control system communicates with the sub-module control system downwards, and communicates with the external control system on the upper side; also includes a main control system and a sub-module control system, the main control system controls the standby state with the sub-module downwards ,
  • multiple redundancy mode settings and switching control are used to balance the reliability of the system and the reliability of the energy consuming device.
  • the present invention sets the redundancy mode of the DC energy consuming device hierarchically, and switches the redundancy mode according to the number of sub-modules that have failed. As the number of levels of the redundancy mode increases, the performance of the corresponding device continues to deteriorate, based on this To perform different processing methods, and feedback the status of the device to the controller of the converter in real time.
  • the hierarchical processing method is that the redundancy of the sub-modules of the energy-consuming device is fully utilized, and the reliability of the device is taken into account with the system. Reliability.
  • Fig. 1 shows a schematic flow chart of a control method of a modular DC energy consuming device according to an embodiment of the present application.
  • Fig. 2 shows a schematic diagram of an application scenario of the method shown in Fig. 1.
  • FIG. 3 shows a schematic diagram of the topological structure of the modular DC energy consumption device involved in the method shown in FIG. 1.
  • 4A-4D show schematic diagrams of the sub-modules of the modular DC energy consumption device shown in FIG. 3.
  • the method shown in FIG. 1 can be applied to the modular DC energy consumption device 20 shown in FIG. 2.
  • the device is composed of M sub-modules 4 in series, and M is an integer greater than or equal to 2; the device also includes a resistor 5, which is connected in series with M sub-modules or/and is distributed in each sub-module middle.
  • the resistors play a role in dissipating energy. They can be centrally arranged and connected in series with M sub-modules. The energy-dissipating resistors can also be distributed in each sub-module. The above two methods can also be used at the same time. Distributed in each sub-module.
  • the sub-module includes a capacitor, a power semiconductor device, and a bypass switch, and the turn-on and turn-off of the power semiconductor device controls the input and withdrawal of the resistance in the circuit. After the bypass switch is closed, short-circuit the sub-module.
  • Sub-module structure 1 As shown in Figure 4A, the sub-module includes a first power semiconductor device and a voltage clamping unit, the collector of the first power semiconductor device is used as the positive terminal of the sub-module, and the emitter is used as the sub-module
  • the voltage clamping unit is composed of a capacitor, a second power and a balance resistor connected in series, and the voltage clamping unit is connected in parallel with the first power semiconductor device; it also includes a third power semiconductor device, a third power semiconductor device It is connected in parallel at both ends of the second power and the equalizing resistor in series; it also includes a bypass switch, and the bypass switch is connected in parallel at both ends of the first power semiconductor device.
  • the first power semiconductor device is a fully controlled power semiconductor device, which may be an IGBT/IGCT
  • the second power semiconductor device may be an IGBT/IGCT/thyristor
  • the third power semiconductor device is a diode.
  • the energy dissipation resistors are preferably arranged in a centralized manner outside the sub-module and connected in series with the sub-module.
  • the main function of the equalizing resistor in the sub-module is to act as the discharge resistance of the capacitor and adjust the capacitor voltage of the sub-module.
  • Sub-module structure 2 As shown in Figure 4B, the sub-module includes a capacitor, a power semiconductor device, a resistor, a first bypass switch and a second bypass switch.
  • the negative pole of the sub-module is used as the negative pole of the sub-module.
  • the power semiconductor device is connected in series with the resistor and then connected in parallel with the capacitor.
  • the first bypass switch is connected in parallel with the capacitor, and the second bypass switch is connected in parallel with the power semiconductor device.
  • Energy belongs to the way that energy dissipation resistors are distributed in each sub-module. In this way, when the bypass command is executed, the second bypass switch is first closed, the capacitor is discharged through the energy dissipation resistor, and then the first bypass switch is closed.
  • the power semiconductor device is a fully controlled power semiconductor device, which may be an IGBT/IGCT.
  • Sub-module structure 3 As shown in Figure 4C, the sub-module includes a capacitor, a first power semiconductor device, a second power semiconductor device, a third power semiconductor device, a resistor and a bypass switch; where the second power semiconductor device The cathode of the device is used as the positive pole of the submodule, and the anode is used as the negative pole of the submodule. After the first power semiconductor device is connected in series with the resistor, it is connected in parallel with the capacitor. The negative pole of the capacitor is connected with the anode of the second power semiconductor device. The power semiconductor device is connected with the cathode of the second power semiconductor device; the bypass switch is connected in parallel with the second power semiconductor device.
  • the first power semiconductor device is a fully-controlled power semiconductor device, which may be an IGBT/IGCT, and the second and third power semiconductor devices are diodes.
  • the main role of the resistor is to dissipate energy, which belongs to the manner in which the dissipating resistors are distributed in each sub-module.
  • Sub-module structure 4 As shown in Figure 4D, similar to the structure described in sub-module structure 3, the second power semiconductor device is a fully controlled power semiconductor device, preferably IGBT/IGCT.
  • the energy resistors are preferably arranged in a centralized manner outside the sub-modules and connected in series with the sub-modules.
  • the main function of the resistors in the sub-modules is to act as a discharge resistor of the capacitor, and adjust the capacitor voltage of the sub-module by turning on and off the first power semiconductor device.
  • the power semiconductor devices distributed in each sub-module control the input and withdrawal of the energy dissipation resistors in the circuit to achieve the goal of controlling the energy consumption speed.
  • the structure 1 and structure 4 respectively include two sets of fully-controlled power semiconductor devices.
  • the turn-on and turn-off of one set of power semiconductor devices control the turn-on and turn-off of the centralized resistance, and the turn-on and turn-off control of the other set of power semiconductor devices.
  • the capacitor voltage of the sub-module; Structure 2 and Structure 3 only include a set of fully-controlled power semiconductor devices, which achieve the purpose of energy consumption by controlling the switching of the energy dissipation resistors in the sub-module, and at the same time stabilize the capacitor voltage of the sub-module.
  • the device also includes a main control system 1 and a sub-module control system.
  • the main control system communicates with the sub-module control system 2 on the lower side, and communicates with the external control system 3 on the upper side; in this embodiment, the external control system
  • the system is the inverter control system.
  • the device is connected in parallel between the DC lines and has a standby state and an energy consumption state; in the standby state, the energy dissipation resistor is not turned on; in the energy consumption state, the device controls the switching of the power semiconductor device in the sub-module Disconnect the DC voltage of the control circuit.
  • the device control method is divided into the following four redundancy modes according to the sub-module failure conditions:
  • the sub-module control system controls the on and off of the power semiconductor device according to the value of the sub-module capacitor voltage; the sub-module closes the bypass switch after a non-communication failure.
  • Three-level redundancy mode In the state of energy consumption, the control target of the line DC voltage is changed, and the line DC voltage stability performance of the device is actively reduced.
  • the device control method includes at least two of the four redundancy modes; when the number of faulty sub-modules in each redundancy mode reaches a preset value, it exits this mode and automatically enters the next redundancy mode .
  • the embodiment in Fig. 1 includes all four redundancy modes.
  • the device stops running and disconnects the connection with the DC line.
  • the four redundancy modes are switched in the order of the number of stages from small to large.
  • it includes four redundancy modes, according to the first, second, third, and fourth switching modes; or includes three redundancy modes, according to the first, second, and fourth switching modes.
  • the device when the redundancy mode reaches the third level, the device sends an alarm signal to the external control system; when the redundancy mode reaches the fourth level, the device sends a serious alarm signal to the external control system.
  • the device before the device enters the failure redundancy control, it first selects the entered redundancy mode according to the number of failed sub-modules in the initial state. Preferably, it starts from the first level redundancy mode, including other situations, such as when After the device is initialized, multiple faulty sub-modules appear at the same time, and the possibility of skipping the previous redundancy mode may appear.
  • control method of the first-level redundancy mode is as follows:
  • Step 1 Set the number of sub-modules allowed to fail in this mode to X.
  • Step 2 When the line voltage is normal, the device is in a standby state; when a line DC overvoltage occurs, the device enters an energy consumption state; the main control system monitors the status of the sub-modules.
  • the line voltage is normal may be that the DC line voltage is less than or equal to the first voltage threshold, and the line DC overvoltage may be that the DC voltage is greater than the first voltage threshold, the same below.
  • Step 3 If a sub-module failure occurs during step 2, the main control system or the sub-module control system will issue a bypass command.
  • Step 4 The main control system accumulates and records the number of fail-by-pass sub-modules.
  • Step 5 Repeat steps 2 to 4, when the number of fail-by-pass sub-modules is greater than or equal to X, exit this mode and enter the next redundancy mode.
  • the two-level redundancy mode control method is as follows.
  • Step 1 Set the number of sub-modules that allow non-communication failure bypass to be Y1 in this mode, and the number of sub-modules that have communication failures to Y2.
  • Step 2 When the line voltage is normal, the device is in a standby state; when a line DC overvoltage occurs, the device enters an energy consumption state; the main control system monitors the status of the sub-modules.
  • Step 3 In the process of step 2, if a sub-module non-communication failure occurs, the main control system or the sub-module control system will issue a bypass command.
  • Step 4 If a communication failure occurs in the sub-module during step 2, the sub-module control system can control the power semiconductor device to be turned on and off in an offline mode to control the capacitor voltage of the sub-module to stabilize within a certain range.
  • Step 5 The main control system accumulatively records the number of bypassed sub-modules and the number of sub-modules with communication failures.
  • Step 6 Repeat steps 2 to 5, when the number of fail-by-pass sub-modules is greater than or equal to Y1 or the number of communication failure sub-modules is greater than or equal to Y2, exit this mode and enter the next redundancy mode.
  • the three-level redundancy mode control method is as follows:
  • Step 1 Set the number of sub-modules that allow non-communication failure bypass in this mode to Z1, and the number of sub-modules that have communication failures to Z2.
  • Step 2 The main control system monitors the status of the sub-modules; if the energy-consuming device is in the energy-consuming state, adjust the control target of the line DC voltage, and actively reduce the line DC voltage stability of the device; if it is in the standby state, maintain the original state.
  • Step 3 In the process of step 2, if a sub-module non-communication failure occurs, the main control system or the sub-module control system will issue a bypass command.
  • Step 4 If a communication failure occurs in the sub-module during step 2, the sub-module control system can control the power semiconductor device to be turned on and off in an offline mode to control the capacitor voltage of the sub-module to stabilize within a certain range.
  • Step 5 The main control system accumulatively records the number of bypassed sub-modules and the number of sub-modules with communication failures.
  • Step 6 Repeat steps 2 to 5, when the number of fail-by-pass submodules is greater than or equal to Z1 or the number of communication failure submodules is greater than or equal to Z2, exit this mode and enter the next redundancy mode.
  • the control method of the four-level redundancy mode is as follows:
  • Step 1 Set the number of sub-modules that are allowed to fail in this mode to W.
  • Step 2 The main control system monitors the status of the sub-modules; if the energy consuming device is in the energy consuming state, all the energy consuming resistors are turned on; if it is in the standby state, the original state is maintained.
  • Step 3 If a sub-module failure occurs during step 2, the main control system or the sub-module control system will issue a bypass command;
  • Step 4 The main control system accumulates and records the number of bypassed sub-modules.
  • Step 5 Repeat steps 2 to 4, when the number of fail-by-pass sub-modules is greater than or equal to W, exit this mode.
  • the main control system when an uplink communication failure of the sub-module control system to the main control system occurs, the main control system will increase the number of bypass sub-modules and the number of communication failure sub-modules at the same time. In this case, since the main control system cannot obtain the status of the sub-module control system, it will deal with the most serious fault, that is, consider both bypass and communication faults.
  • an autonomous voltage equalization strategy when in the standby state, an autonomous voltage equalization strategy is executed.
  • the sub-module control system controls the capacitor voltage of the sub-module by controlling the turn-on and turn-off of the power semiconductor device. In a certain range.
  • the bypass switch is a high-speed mechanical switch or a power semiconductor device, or a combination of the two; the high-speed mechanical switch accepts a command from the sub-module control system to switch on; the power semiconductor device breaks down when subjected to overvoltage A short circuit causes the sub-module to be bypassed.
  • the communication mode between the main control system and the sub-module control system is a one-to-one communication mode, or a one-to-many master-slave communication mode, or a hand-in-hand ring network communication mode.
  • the external control system is a control system of a converter capable of controlling the DC voltage or transmission power of the DC line where the device is located.
  • the power semiconductor device of the non-faulty sub-module accepts the instruction of the main control system and executes the turn-on or turn-off command;
  • the power semiconductor device of the communication failure sub-module accepts the instruction of the sub-module control system , Execute the turn-on or turn-off command.
  • the manner of closing the bypass switch includes:
  • Main control closed The main control control system gives a bypass command to trigger the switch mechanism to close.
  • Sub-module close When the communication fails, the sub-module control system will give a bypass command to trigger the switch mechanism to close.
  • Passive closing The switch mechanism is automatically triggered to close through the hardware loop.
  • Breakdown closure Short-circuit breakdown when the power semiconductor device is subjected to overvoltage; corresponding to the bypass mode in Figure 4D.
  • the specific method for changing the control target of the line DC voltage in step 2 of the three-level redundancy mode includes:
  • step 6 of the secondary redundancy mode when the sum of the number of bypassed sub-modules and the number of communication-failed sub-modules is greater than or equal to the preset total limit YN, it will also exit this mode and enter the next mode. ⁇ Y1+Y2.
  • step 6 of the three-level redundancy mode when the sum of the number of bypassed sub-modules and the number of communication-failed sub-modules is greater than or equal to the preset total limit ZN, it will also exit this mode and enter the next mode. ⁇ Z1+Z2.
  • FIG. 5 shows a schematic flowchart of a control method of a modular DC energy consuming device according to another embodiment of the present application.
  • the method 2000 can be used to control a modular DC energy consuming device.
  • the topology, application scenarios, and sub-modules of the energy consuming device may be as shown in Figures 2 to 4, and will not be repeated here.
  • the method 2000 may include: S210 and S220.
  • the failure may include a communication failure and a non-communication failure.
  • the number of faulty submodules Nb may include at least one of the number of communication faulty submodules Nbc, the number of non-communication faulty submodules Nbb, and the number of fail-by-pass submodules Nbs.
  • the number of faulty submodules Nb may also include at least two of the above three items. Sum. Among them, the number of faulty short-circuit sub-modules Nbs is the number of faulty sub-modules that have been bypassed.
  • the redundancy mode level Lm can be determined according to the aforementioned number of failed sub-modules Nb, and the corresponding redundancy mode can be entered.
  • the method 2000 at least two redundancy mode levels and at least two corresponding levels of redundancy mode may be included.
  • each level of redundancy module can correspond to different entry thresholds and exit thresholds.
  • the exit threshold may include an upper threshold
  • the entry threshold may include a lower threshold.
  • the lower threshold of each level of redundancy mode may be the same as the upper threshold of the lower level of redundancy mode.
  • the redundancy mode level Lm may be determined according to the number of failed sub-modules and the foregoing threshold, and the redundancy mode corresponding to the redundancy mode level Lm may be entered.
  • FIG. 6 shows a schematic flow diagram of the unfolding steps of S120 in the method shown in FIG. 5.
  • the method 2000 may include 4 levels of redundancy mode, and may include four corresponding redundancy modes, namely: the first level redundancy mode ML1 and the second level redundancy mode ML2. , Three-level redundancy mode ML3 and four-level redundancy mode ML4.
  • the redundancy mode levels included in the method 2000 may also be other numbers.
  • the upper threshold corresponding to the above 4-level redundancy mode may be the first threshold X, the second threshold Y, the third threshold Z, and the fourth threshold W, respectively.
  • S220 may include: S221, S222, S223, and S224, and S230, S240, S250, S260, and S270.
  • S221 it may include determining whether the number of failed sub-modules Nb is less than the first threshold X. If the judgment result is yes, go to S230; if the judgment result is no, go to S222.
  • the number of faulty sub-modules may include the number of communication faulty sub-modules Nbc and the number of fail-open sub-modules Nbs.
  • the judging part in S222 can be replaced with: judging whether the number of communication faulty sub-modules Nbc ⁇ threshold Y2 and the number of fail-by-pass sub-modules Nbs ⁇ threshold Y1.
  • the number of faulty sub-modules may include the number of communication faulty sub-modules Nbc and the number of fail-open sub-modules Nbs.
  • the judgment part of S223 can be replaced by: judging whether the number of communication faulty sub-modules Nbc ⁇ threshold Z2 and the number of fail-by-pass sub-modules Nbs ⁇ threshold Z1.
  • S224 it may include determining whether the number of failed sub-modules Nb is less than the fourth threshold W. If the judgment result is yes, go to S260; if the judgment result is otherwise, go to S270 and stop running.
  • S230-S260 may respectively enter the first-level redundancy mode ML1-enter the four-redundancy mode ML4, and execute the operation process corresponding to the redundancy mode. In any one of S230-S260, it may include determining whether the exit condition of the current redundancy mode is satisfied. If the exit conditions of the current redundancy mode are met, the current redundancy mode can be exited. After exiting the current redundancy mode, you can directly enter the next level of redundancy mode; you can also enter S210 again, re-determine the redundancy mode level Lm by the number of failed sub-modules, and enter the redundancy mode corresponding to the redundancy mode level Lm .
  • the current redundancy mode can be compared with the upper threshold of the current redundancy mode based on the number of failed sub-modules, and the comparison result is used as the exit condition of the current redundancy mode.
  • S270 can be entered.
  • the operations specifically included in the one-level redundancy mode ML1-four-redundancy mode ML4 may be as shown in the example embodiments shown in FIGS. 7-10. In the following, a detailed example will be given to the one-level redundancy mode ML1-four-redundancy mode ML4.
  • the energy-consuming device can be stopped and the DC line can be disconnected.
  • Step S120 in the method shown in FIG. 1 may not be limited to the process shown in FIG. 6.
  • the modular DC energy consumption device to which the method 2000 is applied may include a plurality of sub-modules connected in series.
  • Each of the sub-modules can be used to control whether the energy dissipation resistor is invested or not, and the level of investment.
  • Each energy dissipation resistor can be set independently of the submodule and controlled by the corresponding submodule; the energy dissipation resistor can also be set inside the submodule and controlled by the submodule where it is located.
  • the energy consuming device may enter an energy consuming state.
  • the energy-consuming state multiple sub-modules inside the energy-consuming device can cooperate.
  • Each sub-module can individually control the input level of the corresponding energy dissipation resistor.
  • the excess power in the DC line can be consumed in a controllable manner, and the DC line voltage can be adjusted within the preset range in this way.
  • the sub-modules configured in the energy consuming device may have a certain degree of redundancy. That is, under normal circumstances, the energy consuming device can maintain the DC line voltage within the aforementioned preset range through the normal operation of some of the included multiple sub-modules.
  • the sub-module may include a bypass switch and a power semiconductor device.
  • the power semiconductor can be turned on/off to control whether the power dissipating resistor is turned on or not, and the power semiconductor's turn-on time and off time can be matched to control the power dissipating resistor's input level.
  • the bypass switch is closed, the sub-module is bypassed and no longer affects the DC line.
  • the sub-module may further include a sub-module control system for controlling at least one of the bypass switch and the power semiconductor device.
  • the energy consuming device may include a main control system, which is in communication connection with the sub-module control system.
  • the main control system can indirectly obtain the status of the sub-module through communication with the sub-module control system, and can indirectly control at least one of the bypass switch and the power semiconductor device of the sub-module through the sub-module control system.
  • the sub-module may also include a hardware loop.
  • the hardware loop can control at least one of the power semiconductor switch and the bypass switch through hardware logic.
  • the sub-module may also include an overvoltage breakdown power semiconductor device.
  • the overvoltage breakdown power semiconductor device can use the voltage at both ends of the overvoltage breakdown power semiconductor device as a basis for judging whether the submodule is faulty. Overvoltage breakdown of the power semiconductor device can also occur when the voltage at both ends exceeds the second preset voltage threshold, and bypass the sub-module where it is located.
  • FIG. 7 shows a schematic flow diagram of the primary redundancy mode in the method shown in FIG. 5.
  • the first level mode ML1 can be entered when the number of faulty sub-modules in the energy consuming device is small.
  • the "fewer number of faulty submodules” may mean that the number of faulty submodules in the energy consuming device is much smaller than the redundant configuration of the energy consuming device, and the energy consuming device can use normal submodules to adjust the DC line voltage in an energy consumption manner. Within the preset range.
  • the primary redundancy mode may include: S231, S232, S233, S234, S236, S237, S238, and S239.
  • the sub-module status of at least one sub-module in the device can be monitored.
  • the sub-module status can include a normal status and a fault status.
  • the failure status can include non-communication failure and communication failure.
  • Communication failures can include uplink communication failures and downlink communication failures.
  • the main control system cannot obtain the status of the sub-module. At this time, it can be judged according to the worst case. That is, it can be determined that the sub-module has both a non-communication failure and a communication failure.
  • the main control system can monitor the status of the sub-modules through communication.
  • the sub-module control system in the sub-module can also monitor the status of the sub-module spontaneously.
  • the hardware logic can also be used by the hardware loop to monitor the communication status of the sub-modules.
  • the overvoltage breakdown power semiconductor device can also monitor the sub-module status by monitoring the voltage across the overvoltage breakdown power semiconductor device.
  • At least one sub-module that has failed can be determined in the energy consuming device, and the failed at least one sub-module can be bypassed.
  • This fault can be all sub-module faults including non-communication faults and communication faults.
  • the main control system can send a bypass command to the sub-module control system of the sub-module, and the sub-module control system controls the bypass switch to close after receiving the bypass command, so as to achieve the purpose of bypassing the sub-module.
  • the sub-module control system can spontaneously control the bypass switch to close, so as to achieve the purpose of bypassing the sub-module.
  • the switching mechanism can be automatically triggered by the hardware loop to cause the bypass switch to close, thereby achieving the purpose of bypassing the sub-module.
  • the power semiconductor device can also be broken down by overvoltage to achieve the purpose of bypassing the sub-module.
  • the number of faulty sub-modules can be accumulated.
  • the number of faulty sub-modules may include at least one of the number of non-communication faulty sub-modules, the number of communication faulty sub-modules, and the number of fail-open sub-modules.
  • the number of faulty sub-modules may also include the sum of at least two of the above three. .
  • the working state of the energy consuming device can be determined according to the DC line voltage.
  • the working state of the energy consumption device may include a standby state and an energy consumption state.
  • the energy consuming device may enter a standby state; when the DC line voltage is greater than the first voltage threshold, the energy consuming device may enter an energy consuming state.
  • S234 may also include: if the energy consuming device is in the standby state, then it can go to S237; if the energy consuming device is in the energy consuming state, then it can go to S236.
  • normal energy consumption processing can be performed.
  • energy consumption resistors can be input by controlling the on/off of power semiconductor devices. And by controlling the on/off of the power semiconductor device, the input level of the energy dissipation resistor can be controlled. Therefore, the excess power in the DC line can be consumed in a controllable manner, and the voltage of the DC line can be adjusted.
  • the input level of the energy dissipation resistor can be adjusted by controlling the on-time and off-time of the power semiconductor device in each cycle. And use this to adjust the power consumption capacity of the energy dissipation resistor and the voltage regulation capacity of the sub-module.
  • an autonomous voltage equalization strategy can be implemented, and the voltage across each sub-module can be adjusted by separately controlling the on/off of the power semiconductor device of each sub-module. Make the DC link voltage relatively balanced by each sub-module to bear. The voltage expectation at both ends of each sub-module can be allocated by the main control system. And the sub-module control system of each sub-module can adjust the voltage at both ends of the sub-module to the expected voltage by controlling the on/off of the power semiconductor device.
  • the power semiconductor device can be controlled to be turned on/off so that the input level of the energy dissipation resistor is negligibly small.
  • S234-S237 can be set before S231-S233 or after S231-S233. S234-S237 can also be executed in parallel or interspersed with S231-S233.
  • the exit condition of the first-level redundancy mode may be: the number of failed sub-modules Nb ⁇ the first threshold X.
  • bypass processing can be used for any faulty sub-module. Therefore, it can be ensured that in the energy-consuming state, the energy-consuming device can use normal sub-modules to adjust the DC line voltage in an energy-consuming manner.
  • the DC line can be kept in the best condition, and the converter connected with the energy-consuming device can be in the best and reliable condition.
  • the foregoing is an example embodiment of the first-level redundancy mode, and the first-level redundancy mode may not be limited thereto.
  • FIG. 8 shows a schematic flowchart of the secondary redundancy mode in the method shown in FIG. 5.
  • the secondary redundancy mode ML2 can be entered when the number of faulty sub-modules in the energy consuming device is large.
  • the “large number of faulty sub-modules” may mean that it is difficult for the energy consuming device to use only normal sub-modules to adjust the DC line voltage within a preset range in an energy-consuming manner.
  • the secondary redundancy mode may include: S241, S242, S243, S244, S246, S247, S248, and S249.
  • S241, S243-S246, and S249 may be similar to S231, S233-S237, and S239 in FIG. 7, respectively, and will not be repeated here.
  • the state of the sub-module includes at least one sub-module that has a non-communication failure. And the at least one sub-module can be bypassed.
  • the bypass mode in S242 can be similar to the bypass mode in S232, and will not be repeated here.
  • an autonomous voltage equalization strategy can be executed, and the autonomous voltage equalization strategy can be as described in S237.
  • the sub-module control system can adjust the voltage at both ends of the sub-module in an offline manner according to the preset voltage control target.
  • the exit condition of the secondary redundancy mode ML2 may also be: the number of fail-by-pass sub-modules Nbs ⁇ the threshold Y1 or the number of communication faulty sub-modules Nbc ⁇ the threshold Y2.
  • the exit condition of the secondary redundancy mode ML2 can also be: the number of fail-by-pass sub-modules Nbs + the number of communication faulty sub-modules Nbc ⁇ the threshold YN.
  • YN may be less than or equal to the sum of Y1 and Y2.
  • non-fatal faults (communication faults) can be used to participate in the normal operation of the energy consuming device.
  • the energy-consuming device can be maintained to maintain relatively normal operation.
  • FIG. 8 is only an exemplary embodiment of the secondary redundancy mode ML2, and the secondary redundancy mode ML2 may not be limited thereto.
  • FIG. 9 shows a schematic flowchart of the three-level redundancy mode in the method shown in FIG. 5.
  • the three-level redundancy mode ML3 can be entered when the number of faulty sub-modules in the energy consuming device is large.
  • the "large number of faulty modules” may mean that the number of faulty sub-modules exceeds the redundant configuration of the energy consuming device, and it is difficult for the energy consuming device to adjust the voltage of the DC line within the aforementioned preset range by means of energy consumption.
  • S250 may include: S251, S252, S253, S254, S256, S257, S258, and S259.
  • S251-S254, S257, and S259 may be similar to those shown in FIG. 8: S241-S244, S247, and S249 respectively, and will not be described in detail.
  • the process of down-regulating energy consumption can be performed. You can actively lower the DC link voltage regulation target in this step or when entering the three-level redundancy mode ML3. And in this step, according to the reduced DC line voltage adjustment target, the DC line voltage can be adjusted by means of energy consumption. Make the DC link voltage in a relatively acceptable state.
  • reducing the DC link voltage adjustment target may include: reducing the adjustment range of the DC link voltage, and reducing the DC link voltage stability adjustment target. Furthermore, if the modular DC energy consumption device adopts a hysteresis control method to control the DC line voltage, that is, the DC line voltage is controlled between the high voltage limit and the low voltage limit, then the high voltage limit and the low voltage limit can be increased. The difference in voltage limits. If the modular DC energy consuming device adopts a closed-loop adjustment of the DC line voltage, the DC line voltage control target value is increased.
  • the exit condition of the three-level redundancy mode ML3 may also be that the number of fail-by-pass sub-modules Nbs ⁇ the threshold Z1 or the number of communication failure sub-modules Nbc ⁇ the threshold Z2.
  • the exit condition of the three-level redundancy mode ML3 can also be the number of fail-by-pass sub-modules Nbs+the number of communication-failed sub-modules Nbc ⁇ the threshold ZN.
  • ZN may be less than or equal to the sum of Z1 and Z2.
  • the three-level redundancy mode ML3 may also include: sending an alarm signal.
  • the energy consuming device when the number of faulty sub-modules of the energy consuming device is too large, which exceeds the redundant setting of the energy consuming device, it is difficult for the energy consuming device to maintain the DC line voltage within the preset range.
  • the target can be adjusted actively by lowering the DC link voltage. And when the energy-consuming device is in the energy-consuming state, adjust the DC line voltage in a relatively acceptable temporary state, maintain the DC line in a relatively normal state, and gain time for system maintenance.
  • the process shown in FIG. 9 is only an exemplary embodiment of the three-level redundancy mode ML3, and the three-level redundancy mode ML3 may not be limited to this.
  • FIG. 10 shows a schematic flowchart of the four-level redundancy mode in the method shown in FIG. 5.
  • the four-level redundancy mode ML4 can be entered.
  • the number of faulty modules is very large, and it may be that the number of faulty sub-modules seriously exceeds the redundancy range of the energy consuming device.
  • S260 may include: S261, S262, S263, S264, S266, S267, S268, and S269.
  • S261-S264, S267, and S269 may be similar to those shown in FIG. 8: S241-S244, S247, and S249, and will not be repeated.
  • full energy consumption can be performed.
  • the full energy consumption may include all energy consumption resistors put into the energy consumption device. Increase the input level of energy dissipation resistors as much as possible, and no longer have any adjustment expectations for the DC line voltage.
  • the exit condition of the four-level redundancy mode ML4 is met. If the judgment result is yes, otherwise, you can go to S261; if the judgment result is yes, you can go to S269 to exit the current redundancy mode.
  • the exit condition of the four-level redundancy mode ML4 may be: the number of failed sub-modules Nb ⁇ the fourth threshold W.
  • the number of faulty sub-modules in the energy consuming device may seriously exceed the redundant configuration of the energy consuming device.
  • the energy-consuming device can put all energy-consuming resistors in the energy-consuming state, and put in the maximum energy-consuming capacity. Within the capacity of the energy-consuming device, maintain the DC link voltage in a relatively good state and gain time for system maintenance.
  • FIG. 10 is only an exemplary embodiment of the four-level redundancy mode ML4, and the four-level redundancy mode ML4 may not be limited thereto.
  • multiple redundancy mode settings and switching control are used to balance the reliability of the system and the reliability of the energy consuming device.
  • the present invention sets the redundancy mode of the DC energy consuming device hierarchically, and switches the redundancy mode according to the number of sub-modules that have failed. As the number of levels of the redundancy mode increases, the performance of the corresponding device continues to deteriorate, based on this To perform different processing methods, and feedback the status of the device to the controller of the inverter in real time.
  • the hierarchical processing method is that the redundancy of the sub-modules of the energy consuming device is fully utilized, and the reliability of the energy consuming device is taken into account. And the reliability of the system.
  • the present invention categorizes the faults of the sub-modules of the DC energy consuming device, and uses the sub-module control system to control the DC voltage automatically under the communication failure, and makes full use of the energy consumption capacity of the device.

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Abstract

一种模块式直流耗能装置故障冗余控制方法，所述模块式直流耗能装置由串联连接的多个子模块串联构成，所述控制方法包括：累计故障子模块数量；根据故障子模块数量确定冗余模式等级，并进入相应冗余模式；至少一个所述冗余模式包括当故障子模块数量达到当前冗余模式的上限阈值时，跳出当前冗余模式，并自动进入更高等级冗余模式。

Description

一种模块式直流耗能装置故障冗余控制方法 技术领域
本申请涉及电力电子技术领域，具体涉及模块式直流耗能装置故障冗余控制方法。
背景技术
国内外对于新能源并网低电压穿越能力都有明确的规范要求。对于采用高压柔性直流输电技术并网的新能源系统，诸如发电端为与风电类似的惯性电源，当受电端发生故障导致交流电网电压跌落时，由于送端换流器为功率控制，有功功率无法送出或者只能部分送出至交流电网。富余有功功率可能会造成直流输电线路的电压升高。该电压升高危害柔性直流换流阀等设备的安全。通常需要在直流线路设置直流耗能装置，消耗过剩的能量，限制直流线路电压。
现有技术中，直流耗能装置通常采用模块化的方式。一旦模块发生故障，为了保证耗能装置的可靠性，现有技术的做法的将故障的模块旁路。当模块旁路数超过一定值时，耗能装置为了自身的安全，就会停止运行，失去耗能能力。此时对于换流器来说就会面临突然升高的直流电压，造成换流器紧急闭锁停运，从而对电网造成冲击。过高的直流电压也会导致换流器的子模块损坏，造成严重后果。换流器的可靠性和直流耗能装置的可靠性难以兼顾。因此，需要在换流器可靠性和直流耗能装置的可靠性之间进行协调和取舍，以提升整个系统的可靠性为最终目标。
发明内容
本申请旨在提供一种模块式直流耗能装置故障冗余控制方法。
本申请的一个实施例提供了一种模块式直流耗能装置故障冗 余控制方法，所述模块式直流耗能装置由串联连接的多个子模块串联构成，所述控制方法包括：累计故障子模块数量；根据故障子模块数量确定冗余模式等级，并进入相应冗余模式；至少一个所述冗余模式包括当故障子模块数量达到当前冗余模式的上限阈值时，跳出当前冗余模式，并自动进入更高等级冗余模式。
进一步地，所述模块式直流耗能装置可以由M个子模块串联构成，M为大于等于2的整数；所述模块式直流耗能装置还包括耗能电阻，所述耗能电阻与所述M个子模块串联连接或/且分布在各个子模块中；所述子模块包括电容、功率半导体器件以及旁路开关，所述功率半导体器件的开通关断控制所述耗能电阻在电路中的投入和退出；所述旁路开关闭合后将所述子模块短接；所述模块式直流耗能装置还包括主控制系统以及子模块控制系统，所述子模块包含所述子模块控制系统，所述主控制系统对下与所述子模块控制系统通讯，对上与外部控制系统通讯；还包括主控制系统以及子模块控制系统，所述主控制系统对下与所述子模块控制所述待机状态，所述耗能电阻不投入；所述耗能状态，所述模块式直流耗能装置通过控制所述子模块中的所述功率半导体器件的开通关断控制直流线路电压；其特征在于，所述冗余模式包括：1)一级冗余模式：所述子模块发生子模块故障后，闭合所述旁路开关，其中所述子模块故障包括子模块通讯故障和子模块非通讯故障；2)二级冗余模式：所述子模块发生所述子模块通讯故障后，所述子模块控制系统根据子模块电容电压值控制所述功率半导体器件的开通关断；所述子模块发生所述子模块非通讯故障后闭合所述旁路开关；3)三级冗余模式：耗能状态下，改变所述直流线路电压的控制目标，主动降低所述模块式直流耗能装置的直流线路电压稳定性能；4)四级冗余模式：耗能状态下，所述模块式直流耗能装置不再控制所述直流线路电压，投入所述耗能电阻；所述控制方法包括所述四种冗余模式之中的至少两种。
利用上述控制方法通过多种冗余模式的设置以及切换控制，兼顾系统的可靠性和耗能装置的可靠性。
本发明通过分级设置直流耗能装置的冗余模式，根据发生故障的子模块个数进行冗余模式的切换，随着冗余模式的级数增加，对应装置性能的不断恶化，以此为依据来执行不同的处理方式，并将装置的状态实时反馈给换流器的控制器，分级的处理方式是耗能装置子模块的冗余度得到了充分的利用，兼顾了装置的可靠性与系统的可靠性。
本发明对直流耗能装置的子模块故障进行了分类处理，在通讯故障下利用子模块控制系统自行控制直流电压，充分利用了装置的耗能能力。
附图说明
图1示出了本申请的一个实施例模块式直流耗能装置的控制方法的流程示意图。
图2示出了图1所示方法的应用场景示意图。
图3示出了图1所示方法所涉及的模块式直流耗能装置的拓扑结构示意图。
图4A-4D示出了图3所示模块式直流耗能装置的子模块的原理示意图。
图5示出了本申请的另一实施例模块式直流耗能装置的控制方法的流程示意图。
图6示出了图5所示方法中的S120的展开步骤流程示意图。
图7示出了图5所示方法中的一级冗余模式的流程示意图。
图8示出了图5所示方法中的二级冗余模式的流程示意图。
图9示出了图5所示方法中的三级冗余模式的流程示意图。
图10示出了图5所示方法中的四级冗余模式的流程示意图。
具体实施方式
以下是通过特定的具体实施例来说明本实用新型所公开有关“一种模块式直流耗能装置故障冗余控制方法”的实施方式，本领域技术人员可由本说明书所公开的内容了解本实用新型的优点与效果。本实用新型可通过其他不同的具体实施例加以施行或应 用，本说明书中的各项细节也可基于不同观点与应用，在不背离本实用新型的精神下进行各种修饰与变更。另外，本实用新型的附图仅为简单示意说明，并非依实际尺寸的描绘，事先声明。以下的实施方式将进一步详细说明本实用新型的相关技术内容，但所公开的内容并非用以限制本实用新型的保护范围。
本申请旨在提供一种模块式直流耗能装置故障冗余控制方法。
本申请的一个实施例提供了一种模块式直流耗能装置故障冗余控制方法，所述模块式直流耗能装置由串联连接的多个子模块串联构成，所述控制方法包括：累计故障子模块数量；根据故障子模块数量确定冗余模式等级，并进入相应冗余模式；至少一个所述冗余模式包括当故障子模块数量达到当前冗余模式的上限阈值时，跳出当前冗余模式，并自动进入更高等级冗余模式。
进一步地，所述模块式直流耗能装置可以由M个子模块串联构成，M为大于等于2的整数；所述模块式直流耗能装置还包括耗能电阻，所述耗能电阻与所述M个子模块串联连接或/且分布在各个子模块中；所述子模块包括电容、功率半导体器件以及旁路开关，所述功率半导体器件的开通关断控制所述耗能电阻在电路中的投入和退出；所述旁路开关闭合后将所述子模块短接；所述模块式直流耗能装置还包括主控制系统以及子模块控制系统，所述子模块包含所述子模块控制系统，所述主控制系统对下与所述子模块控制系统通讯，对上与外部控制系统通讯；还包括主控制系统以及子模块控制系统，所述主控制系统对下与所述子模块控制所述待机状态，所述耗能电阻不投入；所述耗能状态，所述模块式直流耗能装置通过控制所述子模块中的所述功率半导体器件的开通关断控制直流线路电压；其特征在于，所述冗余模式包括：1)一级冗余模式：所述子模块发生子模块故障后，闭合所述旁路开关，其中所述子模块故障包括子模块通讯故障和子模块非通讯故障；2)二级冗余模式：所述子模块发生所述子模块通讯故障后，所述子模块控制系统根据子模块电容电压值控制所述功率半导体 器件的开通关断；所述子模块发生所述子模块非通讯故障后闭合所述旁路开关；3)三级冗余模式：耗能状态下，改变所述直流线路电压的控制目标，主动降低所述模块式直流耗能装置的直流线路电压稳定性能；4)四级冗余模式：耗能状态下，所述模块式直流耗能装置不再控制所述直流线路电压，投入所述耗能电阻；所述控制方法包括所述四种冗余模式之中的至少两种。
利用上述控制方法通过多种冗余模式的设置以及切换控制，兼顾系统的可靠性和耗能装置的可靠性。
本发明通过分级设置直流耗能装置的冗余模式，根据发生故障的子模块个数进行冗余模式的切换，随着冗余模式的级数增加，对应装置性能的不断恶化，以此为依据来执行不同的处理方式，并将装置的状态实时反馈给换流器的控制器，分级的处理方式是耗能装置子模块的冗余度得到了充分的利用，兼顾了装置的可靠性与系统的可靠性。
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
应当理解，本申请的权利要求、说明书及附图中的术语“第一”、“第二”、“第三”和“第四”等是用于区别不同对象，而不是用于描述特定顺序。本申请的说明书和权利要求书中使用的术语“包括”和“包含”指示所描述特征、整体、步骤、操作、元素和/或组件的存在，但并不排除一个或多个其它特征、整体、步骤、操作、元素、组件和/或其集合的存在或添加。
还应当理解，在此本申请说明书中所使用的术语仅仅是出于描述特定实施例的目的，而并不意在限定本申请。如在本申请说明书和权利要求书中所使用的那样，除非上下文清楚地指明其它情况，否则单数形式的“一”、“一个”及“该”意在包括复数形式。还应当进一步理解，在本申请说明书和权利要求书中使用的 术语“和/或”是指相关联列出的项中的一个或多个的任何组合以及所有可能组合，并且包括这些组合。
图1示出了本申请的一个实施例模块式直流耗能装置的控制方法的流程示意图。图2示出了图1所示方法的应用场景示意图。图3示出了图1所示方法所涉及的模块式直流耗能装置的拓扑结构示意图。图4A-4D示出了图3所示模块式直流耗能装置的子模块的原理示意图。
图1所示方法可以应用于图2所示的模块式直流耗能装置20中。如图2所示，所述装置由M个子模块4串联构成，M为大于等于2的整数；所述装置还包括电阻5，所述电阻与M个子模块串联连接或/且分布在各个子模块中。
所述电阻起到耗能作用，可以集中布置，与M个子模块串联连接，也可以把耗能电阻分布在各个子模块中，也可以同时采用上述两种方式，即一部分电阻集中布置，其他电阻分布在各个子模块中。
所述子模块包括电容、功率半导体器件以及旁路开关，功率半导体器件的开通关断控制电阻在电路中的投入和退出。旁路开关闭合后将子模块短接。
以下列举了4种典型的子模块的实施例，如图4A-4D所示：
(1)子模块结构1：如图4A所示，所述子模块包括第一功率半导体器件和电压钳位单元，第一功率半导体器件的集电极作为子模块的正端，发射极作为子模块的负端；所述电压钳位单元由电容、第二功率和均衡电阻串联连接构成，所述电压钳位单元和第一功率半导体器件并联；还包括第三功率半导体器件，第三功率半导体器件并联连接在串联的第二功率和均衡电阻两端；还包括旁路开关，旁路开关并联在第一功率半导体器件两端。
优选地，第一功率半导体器件为全控型功率半导体器件，可以是IGBT/IGCT，第二功率半导体器件可以是IGBT/IGCT/晶闸管，第三功率半导体器件是二极管。
采用这种子模块时，耗能电阻优选采用集中式布置在子模块 外部，与子模块串联，子模块中的均衡电阻的主要作用是作为电容的放电电阻，调节子模块电容电压。
(2)子模块结构2：如图4B所示，所述子模块包括电容、功率半导体器件、电阻、第一旁路开关与第二旁路开关，其中电容的正极作为子模块的正极，电容的负极作为子模块的负极，功率半导体器件与电阻串联后与电容并联，第一旁路开关与电容并联，第二旁路开关与功率半导体器件并联；在本实施例中，电阻主要作用为耗能，属于耗能电阻分布在各个子模块中的方式。采用这种方式时，在执行旁路命令时，先闭合第二旁路开关，电容通过耗能电阻放电，再闭合第一旁路开关。优选地，功率半导体器件为全控型功率半导体器件，可以是IGBT/IGCT。
(3)子模块结构3：如图4C所示，所述子模块包括电容、第一功率半导体器件、第二功率半导体器件、第三功率半导体器件、电阻与旁路开关；其中第二功率半导体器件的阴极作为子模块的正极，阳极作为子模块的负极；第一功率半导体器件与电阻串联后，再与电容并联，电容的负极与第二功率半导体器件的阳极连接，电容的正极经第三功率半导体器件与第二功率半导体器件的阴极连接；旁路开关与第二功率半导体器件并联。
优选地，第一功率半导体器件为全控型功率半导体器件，可以是IGBT/IGCT，第二、三功率半导体器件是二极管。
在本实施例中，电阻主要作用为耗能，属于耗能电阻分布在各个子模块中的方式。
(4)子模块结构4：如图4D所示，与子模块结构3所述的结构相似，其中第二功率半导体器件为全控型功率半导体器件，优选IGBT/IGCT，在该方式中，耗能电阻优选采用集中式布置在子模块外部，与子模块串联，子模块中的电阻的主要作用是作为电容的放电电阻，通过第一功率半导体器件的开通、关断调节子模块电容电压。
由此可见。在本实施例中，无论电阻采用何种布置方式，都是由分布在各个子模块中的功率半导体器件控制耗能电阻在电路 中的投入和退出，以达到控制耗能速度的目标。
其中结构1和结构4分别包括两组全控型功率半导体器件，其中一组功率半导体器件的导通、关断控制集中式电阻的投退，另一组功率半导体器件的导通、关断控制子模块的电容电压；而结构2和结构3仅包括一组全控型功率半导体器件，通过控制子模块中的耗能电阻的投退达到耗能的目的，同时稳定子模块电容电压。
以上四种子模块的实施方式为典型的应用方式，其他应用上述耗能原理的子模块均适用本发明的控制方法。
如图2所示，所述装置还包括主控制系统1以及子模块控制系统，主控制系统对下与子模块控制系统2通讯，对上与外部控制系统3通讯；本实施例中，外部控制系统为换流器的控制系统。
所述装置并联连接在直流线路之间，存在待机状态和耗能状态；所述待机状态，耗能电阻不投入；所述耗能状态，所述装置通过控制子模块中功率半导体器件的开通关断控制线路直流电压。
如图1所示，所述装置控制方法在于根据子模块故障情况，分为以下四种冗余模式：
1)一级冗余模式：子模块发生故障后，闭合旁路开关。
2)二级冗余模式：子模块发生通讯故障后，子模块控制系统根据子模块电容电压值控制功率半导体器件的开通关断；子模块发生非通讯故障后闭合旁路开关。
3)三级冗余模式：耗能状态下，改变线路直流电压的控制目标，主动降低装置的线路直流电压稳定性能。
4)四级冗余模式：耗能状态下，装置不再控制直流线路电压，一直投入电阻。
所述装置控制方法包括所述四种冗余模式之中的至少两种；当每种冗余模式下故障子模块数量达到预先的设定值后，跳出本模式，自动进入下一个冗余模式。
图1中的实施例为包括了全部四种冗余模式的情况。
其中，当所有冗余模式均跳出时，装置停止运行，并分断与直流线路的连接。
其中，优选地，所述四种冗余模式按照级数由小到大的次序进行切换。
例如，包括四种冗余模式，按照一级、二级、三级、四级的切换方式；或者包括三种冗余模式，按照一级、二级、四级的切换方式。
其中，优选地，当冗余模式到达三级时，装置向外部控制系统发出报警信号；当冗余模式到达四级时，装置向外部控制系统发出严重报警信号。
如图1所示，当装置进入故障冗余控制之前，首先根据初始状态下故障子模块的数量选择进入的冗余模式，优选地，从一级冗余模式开始，也包括其他情况，如当装置启动初始化后，同时出现了多个故障子模块，可能出现跳过前面冗余模式的可能性。
其中，所述一级冗余模式控制方法如下：
步骤1：设定该模式下允许故障的子模块数量为X。
步骤2：当线路电压正常时，装置处于待机状态；当发生线路直流过压时，装置进入耗能状态；主控制系统监测子模块状态。其中，线路电压正常可以是直流线路电压小于等于第一电压阈值，线路直流过压可以是直流电压大于第一电压阈值，下同。
步骤3：步骤2过程中如发生子模块故障，则由主控制系统或子模块控制系统下发旁路命令。
步骤4：主控制系统累积记录故障旁路的子模块数量。
步骤5：重复步骤2～4，当故障旁路子模块数量大于等于X时，跳出本模式，进入下一个冗余模式。
所述二级冗余模式控制方法如下。
步骤1：设定该模式下允许发生非通讯故障旁路的子模块数量为Y1，通讯故障的子模块数量为Y2。
步骤2：线路电压正常时，装置处于待机状态；当发生线路直流过压时，装置进入耗能状态；主控制系统监测子模块状态。
步骤3：步骤2过程中如发生子模块非通讯故障，则由主控制系统或子模块控制系统下发旁路命令。
步骤4：步骤2过程中如发生子模块通讯故障，则子模块控制系统离线方式下通过控制功率半导体器件的开通关断，控制子模块电容电压稳定在一定范围。
步骤5：主控制系统累积记录旁路的子模块数量和通讯故障的子模块数量。
步骤6：重复步骤2～5，当故障旁路子模块数量大于等于Y1或通讯故障的子模块数量大于等于Y2时，跳出本模式，进入下一个冗余模式。
所述三级冗余模式控制方法如下：
步骤1：设定该模式下允许发生非通讯故障旁路的子模块数量为Z1，通讯故障的子模块数量为Z2。
步骤2：主控制系统监测子模块状态；如耗能装置处于耗能状态，调节线路直流电压的控制目标，主动降低装置的线路直流电压稳定性能；如处于待机状态，则维持原状态。
步骤3：步骤2过程中如发生子模块非通讯故障，则由主控制系统或子模块控制系统下发旁路命令。
步骤4：步骤2过程中如发生子模块通讯故障，则子模块控制系统离线方式下通过控制功率半导体器件的开通关断，控制子模块电容电压稳定在一定范围。
步骤5：主控制系统累积记录旁路的子模块数量和通讯故障的子模块数量。
步骤6：重复步骤2～5，当故障旁路子模块数量大于等于Z1或通讯故障的子模块数量大于等于Z2时，跳出本模式，进入下一个冗余模式。
所述四级冗余模式控制方法如下：
步骤1：设定该模式下允许发生故障的子模块数量为W。
步骤2：主控制系统监测子模块状态；如耗能装置处于耗能状态，将耗能电阻全部投入；如处于待机状态，则维持原状态。
步骤3：步骤2过程中如发生子模块故障，则由主控制系统或子模块控制系统下发旁路命令；
步骤4：主控制系统累积记录旁路的子模块数量。
步骤5：重复步骤2～4，当故障旁路子模块数量大于等于W，则跳出本模式。
在上述的四级冗余模式控制方法中，当发生子模块控制系统对主控制系统的上行通讯故障时，主控制系统将同时增加旁路子模块数量和通讯故障子模块数量。在这种情况下，由于主控系统无法获得子模块控制系统的状态，将以最为严重的故障情况处理，即同时考虑旁路和通讯故障两种情况。
在上述的四级冗余模式控制方法中，处于待机状态时，执行自主均压策略，所述自主均压策略下，子模块控制系统通过控制功率半导体器件的开通、关断控制子模块电容电压在一定范围。
其中，所述旁路开关为高速机械开关或功率半导体器件，或二者的组合；所述高速机械开关接受子模块控制系统的命令动作合闸；所述功率半导体器件在承受过电压时击穿短路，使子模块被旁路。
其中，主控制系统对下与子模块控制系统通讯方式为一对一的通讯方式，或一对多的主从通讯方式，或手拉手的环网通讯方式。
其中，所述外部控制系统为能够控制装置所在直流线路的直流电压或传输功率的换流器的控制系统。
在上述的四级冗余模式控制方法中，，无故障子模块的功率半导体器件接受主控制系统的指令，执行开通或关断命令；通讯故障子模块的功率半导体器件接受子模块控制系统的指令，执行开通或关断命令。
在上述的四级冗余模式控制方法中，所述闭合旁路开关的方式包括：
主控闭合：由主控制控制系统给出旁路命令，触发开关机构闭合。
子模块闭合：通讯故障时，由子模控制系统给出旁路命令，触发开关机构闭合。
被动闭合：通过硬件回路自动触发开关机构闭合。
击穿闭合：通过功率半导体器件在承受过电压时击穿短路；对应图4D的旁路方式。
其中，在三级冗余模式步骤2中改变线路直流电压的控制目标具体方法包括：
增加滞环控制环宽：如装置采用滞环控制方式控制直流线路电压，即将线路直流电压控制在高电压限值与低电压限值之间，则增加高电压限值与低电压限值的差。
增加闭环控制目标值：如装置采用直流线路电压闭环调节的方式，则提高直流线路电压控制目标值。
其中，二级冗余模式步骤6中当旁路的子模块数量和通讯故障的子模块数量总和大于等于预先设定总数限值YN时，也会跳出本模式，进入下一模式，所述YN≤Y1+Y2。
其中，三级冗余模式步骤6中当旁路的子模块数量和通讯故障的子模块数量总和大于等于预先设定总数限值ZN时，也会跳出本模式，进入下一模式，所述ZN≤Z1+Z2。
图5示出了本申请的另一实施例模块式直流耗能装置的控制方法的流程示意图。
如图5所示，方法2000可以用于控制模块式直流耗能装置。该耗能装置的拓扑结构、应用场景、及子模块可以如图2-图4所示，在此不做赘述。方法2000可以包括：S210和S220。
在S210中，可以包括确定耗能装置中的故障子模块数量Nb。可选地，该故障可以包括通讯故障和非通讯故障。该故障子模块数量Nb可以包括通讯故障子模块数量Nbc、非通讯故障子模块数量Nbb和故障旁路子模块数量Nbs中的至少一项，故障子模块数量Nb还可以包括以上三项中至少两项之和。其中，故障短路子模块数量Nbs是已经进行旁路处理的故障子模块的数量。
在S220中，可以根据前述故障子模块数量Nb确定冗余模式 等级Lm，并进入相应的冗余模式。在方法2000中，可以包括至少两个冗余模式等级，以及至少两个相应等级冗余模式。其中，每个等级冗余模块可以对应不同的进入阈值和退出阈值。可选地，退出阈值可以包括上限阈值，进入阈值可以包括下限阈值。可选地，每一等级冗余模式的下限阈值可以与低一等级冗余模式的上限阈值相同。可选地，在S220可以根据故障子模块数量和上述阈值确定冗余模式等级Lm，并进入冗余模式等级Lm对应的冗余模式。
图6示出了图5所示方法中的S120的展开步骤流程示意图。
如图6所示的示例实施例所示，方法2000可以包括4个冗余模式等级，以及可以包括相应的四个冗余模式，分别为：一级冗余模式ML1、二级冗余模式ML2、三级冗余模式ML3和四级冗余模式ML4。可选地，方法2000包括的冗余模式等级也可以是其他数量。可选地，以上4等级冗余模式对应的上限阈值可以分别是第一阈值X、第二阈值Y、第三阈值Z和第四阈值W。
如图6所示，S220可以包括：S221、S222、S223和S224以及S230、S240、S250、S260和S270。
在S221中，可以包括判断故障子模块数量Nb是否小于第一阈值X。如果判断结果为是，则进入S230；如果判断结果为否，则进入S222。
在S222中，可以包括判断故障子模块数量Nb是否小于第二阈值Y。如果判断结果为是，则进入S240；如果判断结果为否，则进入S223。可选地，故障子模块数量可以包括通讯故障子模块数量Nbc和故障旁路子模块数量Nbs。可选地，S222中的判断部分可以换成：判断是否通讯故障子模块数量Nbc<阈值Y2且故障旁路子模块数量Nbs<阈值Y1。
在S223中，可以包括判断故障子模块数量Nb是否小于第三阈值Z。如果判断结果为是，则进入S250；如果判断结果为否，则进入S224。可选地，故障子模块数量可以包括通讯故障子模块数量Nbc和故障旁路子模块数量Nbs。可选地，S223的判断部分 可以换成：判断是否通讯故障子模块数量Nbc<阈值Z2且故障旁路子模块数量Nbs<阈值Z1。
在S224中，可以包括判断故障子模块数量Nb是否小于第四阈值W。如果判断结果为是，则进入S260；如果判断结果为否则进入S270，停止运行。
S230-S260可以分别为进入一级冗余模式ML1-进入四冗余模式ML4，并执行所在冗余模式对应的操作流程。在S230-S260中的任意一项中，均可以包括判断是否满足当前冗余模式的退出条件。如果满足当前冗余模式的退出条件，则可以退出当前冗余模式。在退出当前冗余模式之后，可以直接进入下一级冗余模式；也可以再次进入S210，重新通过故障子模块数量确定冗余模式等级Lm，以及进入与冗余模式等级Lm对应的冗余模式。
可选地，当前冗余模式可以根据故障子模块数量与当前冗余模式的上限阈值做比较，并把比较结果作为当前冗余模式的退出条件。在满足最高等级冗余模式的退出条件时，可以进入S270。可选地，一级冗余模式ML1-四冗余模式ML4所具体包含的操作可以如图7-10所示的示例实施例所示。在后文将对一级冗余模式ML1-四冗余模式ML4做详细的举例说明。
在S270中，耗能装置可以停止运行，并可以断开直流线路连接。
如图1所示方法中步骤S120也可以不限于图6所示的流程。
如图3所示，可选地，方法2000所应用的模块式直流耗能装置可以包括串联连接的多个子模块。其中每个子模块可以用于控制耗能电阻的投入与否，及投入水平。其中耗能电阻可以为多个。每个耗能电阻可以独立于子模块设置，并受对应子模块控制；耗能电阻也可以设置于子模块内部，由所在子模块控制。
在直流线路电压超过第一电压阈值时，耗能装置可以进入耗能状态。在耗能状态下，耗能装置内部的多个子模块可以协同配合。每个子模块可以各自控制对应的耗能电阻的投入水平。从而可以可控地消耗直流线路中的多余电能，并可以通过此方式调节 直流线路电压处于预设范围内。可选地，耗能装置中配置的子模块可以存在一定冗余。即，在一般情况下，在耗能装置可以通过所包含多个子模块中的部分子模块的正常工作，即可维持直流线路电压处于前述预设范围内。
可选地，子模块可以包括旁路开关和功率半导体器件。可以通过功率半导体的导通/断开来控制耗能电阻的投入与否，以及可以通过功率半导体的导通时长和断开时长的配合来控制耗能电阻的投入水平。当旁路开关闭合时，该子模块被旁路，不再对直流线路产生影响作用。
子模块还可以包括子模块控制系统，用于控制旁路开关和功率半导体器件中的至少一个。可选地，耗能装置可以包括主控制系统，与子模块控制系统通讯连接。主控制系统可以通过与子模块控制系统之间的通讯间接获取子模块状态，以及可以通过子模块控制系统间接控制子模块的旁路开关和功率半导体器件中的至少一个。
可选地，子模块也可以包括硬件回路。硬件回路可以通过硬件逻辑控制功率半导体开关和旁路开关中的至少一个。
可选地，子模块也可以包括过压击穿功率半导体器件。该过压击穿功率半导体器件可以把过压击穿功率半导体器件两端电压作为子模块是否故障的判断依据。过压击穿功率半导体器件也可以在两端电压超过第二预设电压阈值时，发生过压击穿，并旁路所在子模块。
图7示出了图5所示方法中的一级冗余模式的流程示意图。
可以在耗能装置中的故障子模块数量较少时进入一级模式ML1。所述“故障子模块数量较少”可以是：耗能装置中发生故障的子模块数量远小于耗能装置的冗余配置，耗能装置可以利用正常子模块通过耗能方式调节直流线路电压处于预设范围内。
如图7所示，一级冗余模式可以包括：S231、S232、S233、S234、S236、S237、S238和S239。
在S231中，可以监测装置内至少一个子模块的子模块状态。 其中，子模块状态可以包括正常状态和故障状态。故障状态可以包括非通讯故障和通讯故障。通讯故障可以包括上行通讯故障和下行通讯故障。可选地，当发生上行通讯故障时，主控制系统无法获取子模块状态。此时可以按照最恶劣情况判断。即，可以认定该子模块既发生非通讯故障，也发生通讯故障。
可选地，在S231中可以由主控制系统通过通讯监测子模块状态。也可以由子模块内的子模块控制系统自发地监测子模块状态。也可以由硬件回路利用硬件逻辑，监控子模块通讯状态。还可以由过压击穿功率半导体器件通过监测过压击穿功率半导体器件两端电压，监测子模块状态。
在S232中，可以根据S231中的监测结果，在耗能装置中确定发生故障的至少一个子模块，并旁路该发生故障的至少一个子模块。该故障可以是包括非通讯故障和通讯故障在内的所有子模块故障。
可选地，可以由主控制系统向子模块的子模块控制系统发送旁路指令，子模块控制系统在接收到旁路命令后，控制旁路开关闭合，从而可以实现旁路子模块的目的。可选地，也可以在通讯故障时，由子模块控制系统自发地控制旁路开关闭合，从而实现旁路子模块的目的。可选地，还可以由硬件回路自动触发开关机构导致旁路开关闭合，从而实现旁路该子模块的目的。还可以由过压击穿功率半导体器件因过压击穿，而实现旁路该子模块的目的。
在S233中，可以累计故障子模块数量。可选地，故障子模块数量可以包括非通讯故障子模块数量、通讯故障子模块数量和故障旁路子模块数量中的至少一项，故障子模块数量也可以包括上述三者中至少两项之和。
在S234中，可以根据直流线路电压确定耗能装置的工作状态。可选地，耗能装置的工作状态可以包括待机状态和耗能状态。可选地，在直流线路电压小于等于第一电压阈值时，耗能装置可以进入待机状态；在直流线路电压大于第一电压阈值时，耗能装置 可以进入耗能状态。在S234中还可以包括：如果耗能装置处于待机状态，则可以进入S237；如果耗能装置处于耗能状态，则可以进入S236。
在S236中，可以进行普通耗能处理。在普通耗能处理中，可以通过控制功率半导体器件的导通/关断，投入耗能电阻。并可以通过控制功率半导体器件的导通/关断，控制耗能电阻的投入水平。从而可以可控地消耗直流线路中的多余电能，调节直流线路电压。可以通过控制每个周期内功率半导体器件的导通时长和关断时长，调整耗能电阻的投入水平。并以此来调节耗能电阻的电能消耗能力和子模块的电压调节能力。
在S237中，可以执行自主均压策略，可以通过分别控制每个子模块的功率半导体器件的导通/关断来调节各个子模块两端的电压。使得直流线路电压相对均衡地由各个子模块分别承受。可以由主控制系统分配各个子模块两端电压预期。并可以由各个子模块的子模块控制系统通过控制功率半导体器件的导通/关断来调节子模块两端电压为该电压预期。在S237中，可以通过控制功率半导体器件的导通/关断使得耗能电阻投入水平小到可以忽略不计。
其中S234-S237可以设置于S231-S233之前，也可以设置于S231-S233之后。S234-S237还可以与S231-S233并行执行或者穿插执行。
在S238中，可以判断是否满足一级冗余模式的退出条件。如果判断结果为否，则进入S231；如果判断结果为是，则可以进入S239，退出当前冗余模式。可选地，一级冗余模式的退出条件可以是：故障子模块数量Nb≥第一阈值X。
在图7所示一级冗余模式ML1下，由于对于任何故障子模块均可采用旁路处理。因而可以确保在耗能状态下，耗能装置可以利用正常的子模块通过耗能方式调节直流线路电压。使得直流线路可以保持最佳状态，并可以确保与耗能装置连接的换流器处于最佳的可靠状态。可选地，以上为一级冗余模式的示例实施例，一级冗余模式也可以不以此为限。
图8示出了图5所示方法中的二级冗余模式的流程示意图。
可选地，可以在耗能装置中的故障子模块数量较多时进入二级冗余模式ML2。可选地，所述“故障子模块数量较多”可以是：耗能装置仅仅利用正常子模块难以通过耗能方式调节直流线路电压处于预设范围内。
如图8所示，二级冗余模式可以包括：S241、S242、S243、S244、S246、S247、S248和S249。其中，S241、S243-S246和S249可以分别与图7中的S231、S233-S237和S239相似，在此不做赘述。
在S242中，可以根据S241中的监测结果，在耗能装置中，确定子模块状态包括非通讯故障的至少一个子模块。并可以旁路该至少一个子模块。S242中的旁路方式与S232中的旁路方式可以相类似，在此不做赘述。
在S247中，对于正常的子模块，可以执行自主均压策略，该自主均压策略可以如S237所述。对于仅发生通讯故障的子模块，可以由子模块控制系统根据预设的电压控制目标，以离线方式，自行调节该子模块两端的电压。
在S248中，二级冗余模式ML2的退出条件也可以是：故障旁路子模块数量Nbs≥阈值Y1或者通讯故障子模块数量Nbc≥阈值Y2。二级冗余模式ML2的退出条件还可以是：故障旁路子模块数量Nbs+通讯故障子模块数量Nbc≥阈值YN。可选地，YN可以小于等于Y1与Y2之和。
在图8所示二级冗余模式ML2中，可以利用非致命故障(通讯故障)参与耗能装置的正常工作。可以在故障子模块数量相对较多时，可以维持耗能装置维持相对正常的运转。可选地，图8仅为二级冗余模式ML2一种示例实施例，二级冗余模式ML2也可以不以此为限。
图9示出了图5所示方法中的三级冗余模式的流程示意图。
可选地，可以在耗能装置中的故障子模块数量很多时进入三级冗余模式ML3。所述“故障模块数量很多”可以是：故障子模 块数量超过耗能装置的冗余配置，耗能装置难以通过耗能方式调节直流线路的电压处于前述预设范围内。
如图9所示，S250可以包括：S251、S252、S253、S254、S256、S257、S258和S259。其中，S251-S254、S257、S259可以分别与图8所示的：S241-S244、S247、S249类似，不做赘述。
在S256中，可以执行降级调节耗能处理。可以在本步骤或者进入三级冗余模式ML3之时，主动降低直流线路电压调节目标。并可以在本步骤中，根据该降低的直流线路电压调节目标，通过耗能方式调节直流线路电压。使得直流线路电压处于相对可以接受的状态。
进一步地，降低直流线路电压调节目标可以包括：缩小直流线路电压的调节幅度，和降低直流线路电压稳定度调节目标。更进一步地，如所述模块式直流耗能装置采用滞环控制方式控制直流线路电压，即将直流线路电压控制在高电压限值与低电压限值之间，则可以增加高电压限值与低电压限值的差。如所述模块式直流耗能装置采用直流线路电压闭环调节的方式，则提高直流线路电压控制目标值。
在S258中，三级冗余模式ML3的退出条件也可以是故障旁路子模块数量Nbs≥阈值Z1或者通讯故障子模块数量Nbc≥阈值Z2。三级冗余模式ML3的退出条件还可以是故障旁路子模块数量Nbs+通讯故障子模块数量Nbc≥阈值ZN。可选地，ZN可以小于等于Z1与Z2之和。
可选地，在三级冗余模式ML3中，还可以包括：发送告警信号。
在图9所示的三级冗余模式ML3中，在耗能装置的故障子模块数量很多，超过耗能装置冗余设置，耗能装置难以维持直流线路电压在预设范围内的情况下，可以主动通过降低直流线路电压调节目标。并在耗能装置处于耗能状态时，调节直流线路电压处于一个相对可以接受的临时状态，维持直流线路处于相对正常的状态，为系统维护赢得时间。图9所述的流程仅为三级冗余模式 ML3的一种示例实施例，三级冗余模式ML3也可以不以此为限。
图10示出了图5所示方法中的四级冗余模式的流程示意图。
可选地，可以在耗能装置中的故障子模块数量非常多时，进入四级冗余模式ML4。所述故障模块数量非常多，可以是故障子模块数量严重超过耗能装置的冗余范围。
如图10所示，S260可以包括：S261、S262、S263、S264、S266、S267、S268和S269。其中，S261-S264、S267、S269可以分别与图8所示的：S241-S244、S247、S249类似，不做赘述。
在S266中，可以执行全力耗能。可选地，该全力耗能可以包括投入耗能装置的全部耗能电阻。尽可能多地提高耗能电阻的投入水平，而不再对直流线路电压有任何的调节预期。
在S268中，可以判断是否满足四级冗余模式ML4的退出条件。如果判断结果为，否则可以进入S261；如果判断结果为是，则可以进入S269，退出当前冗余模式。可选地，四级冗余模式ML4的退出条件可以是：故障子模块数量Nb≥第四阈值W。
在图10所示的四级冗余模式中，可以在耗能装置中的故障子模块数量严重超过耗能装置的冗余配置时。耗能装置可以在耗能状态下投入全部耗能电阻，投入最大的耗能能力。在耗能装置能力范围内，维持直流线路电压处于相对较佳状态，并为系统维护赢得时间。图10仅为四级冗余模式ML4的一种示例实施例，四级冗余模式ML4也可以不以此为限。
利用上述控制方法通过多种冗余模式的设置以及切换控制，兼顾系统的可靠性和耗能装置的可靠性。
本发明通过分级设置直流耗能装置的冗余模式，根据发生故障的子模块个数进行冗余模式的切换，随着冗余模式的级数增加，对应装置性能的不断恶化，以此为依据来执行不同的处理方式，并将装置的状态实时反馈给换流器的控制器，分级的处理方式是耗能装置子模块的冗余度得到了充分的利用，兼顾了耗能装置的可靠性与系统的可靠性。
本发明对直流耗能装置的子模块故障进行了分类处理，在通 讯故障下利用子模块控制系统自行控制直流电压，充分利用了装置的耗能能力。
在上述实施例中，对各个实施例的描述都各有侧重，某个实施例中没有详述的部分，可以参见其他实施例的相关描述。上述实施例的各技术特征可以进行任意的组合，为使描述简洁，未对上述实施例中的各个技术特征所有可能的组合都进行描述，然而，只要这些技术特征的组合不存在矛盾，都应当认为是本说明书记载的范围。
以上对本申请实施例进行了详细介绍，本文中应用了具体个例对本申请的原理及实施方式进行了阐述，以上实施例的说明仅用于帮助理解本申请的方法及其核心思想。同时，本领域技术人员依据本申请的思想，基于本申请的具体实施方式及应用范围上做出的改变或变形之处，都属于本申请保护的范围。综上所述，本说明书内容不应理解为对本申请的限制。

Claims (19)

  1. 一种模块式直流耗能装置故障冗余控制方法，所述模块式直流耗能装置由串联连接的多个子模块构成，所述控制方法包括：
    累计故障子模块数量；
    根据故障子模块数量确定冗余模式等级，并进入相应冗余模式；
    至少一个所述冗余模式包括当故障子模块数量达到当前冗余模式的上限阈值时，跳出当前冗余模式，并自动进入更高等级冗余模式。
  2. 根据权利要求1所述的控制方法，所述模块式直流耗能装置由M个子模块串联构成，M为大于等于2的整数；所述模块式直流耗能装置还包括耗能电阻，所述耗能电阻与所述M个子模块串联连接或/且分布在各个子模块中；
    所述子模块包括电容、功率半导体器件以及旁路开关，所述功率半导体器件的开通关断控制所述耗能电阻在电路中的投入和退出；所述旁路开关闭合后将所述子模块短接；
    所述模块式直流耗能装置还包括主控制系统以及子模块控制系统，所述子模块包含所述子模块控制系统，所述主控制系统对下与所述子模块控制系统通讯，对上与外部控制系统通讯；
    还包括主控制系统以及子模块控制系统，所述主控制系统对下与所述子模块控制所述待机状态，所述耗能电阻不投入；所述耗能状态，所述模块式直流耗能装置通过控制所述子模块中的所述功率半导体器件的开通关断控制直流线路电压；
    其特征在于，所述冗余模式包括：
    1)一级冗余模式：所述子模块发生子模块故障后，闭合所述旁路开关，其中所述子模块故障包括子模块通讯故障和子模块非通讯故障；
    2)二级冗余模式：所述子模块发生所述子模块通讯故障后，所述子模块控制系统根据子模块电容电压值控制所述功率半导体器件的开通关断；所述子模块发生所述子模块非通讯故障后闭合所述旁路开关；
    3)三级冗余模式：耗能状态下，改变所述直流线路电压的控制目标，主动降低所述模块式直流耗能装置的直流线路电压稳定性能；
    4)四级冗余模式：耗能状态下，所述模块式直流耗能装置不再控制所述直流线路电压，投入所述耗能电阻；
    所述控制方法包括所述四种冗余模式之中的至少两种。
  3. 根据权利要求2所述的模块式直流耗能装置故障冗余控制方法，其特征在于，当所有冗余模式均跳出时，所述模块式直流耗能装置停止运行，并分断与直流线路的连接。
  4. 根据权利要求2所述的模块式直流耗能装置故障冗余控制方法，其特征在于，所述四种冗余模式按照级数由小到大的次序进行切换。
  5. 根据权利要求2所述的模块式直流耗能装置故障冗余控制方法，其特征在于，当所述冗余模式等级到达三级时，装置向外部控制系统发出报警信号；当所述冗余模式等级到达四级时，装置向外部控制系统发出严重报警信号。
  6. 根据权利要求2所述的模块式直流耗能装置故障冗余控制方法，其特征在于，所述一级冗余模式控制方法如下：
    步骤1：设定该模式下允许故障的子模块数量为X；
    步骤2：监测子模块状态；
    步骤3：步骤2过程中如发生子模块故障，则由主控制系统或子模块控制系统下发旁路命令；
    步骤4：主控制系统累积记录故障旁路的子模块数量；
    步骤5：重复步骤2～4，当故障旁路子模块数量大于等于X时，跳出本模式，进入下一个冗余模式。
  7. 根据权利要求2所述的模块式直流耗能装置故障冗余控制方法，其特征在于，所述二级冗余模式控制方法如下：
    步骤1：设定该模式下允许发生非通讯故障旁路的子模块数量为Y1，通讯故障的子模块数量为Y2；
    步骤2：监测子模块状态；
    步骤3：步骤2过程中如发生子模块非通讯故障，则由主控制系统或子模块控制系统下发旁路命令；
    步骤4：步骤2过程中如发生子模块通讯故障，则子模块控制系统离线方式下通过控制功率半导体器件的开通关断，控制子模块电容电压 稳定在预设范围内；
    步骤5：主控制系统累积记录旁路的子模块数量和通讯故障的子模块数量；
    步骤6：重复步骤2～5，当故障旁路子模块数量大于等于Y1或通讯故障的子模块数量大于等于Y2时，跳出本模式，进入下一个冗余模式。
  8. 根据权利要求2所述的模块式直流耗能装置故障冗余控制方法，其特征在于，所述三级冗余模式控制方法如下：
    步骤1：设定该模式下允许发生非通讯故障旁路的子模块数量为Z1，通讯故障的子模块数量为Z2；
    步骤2：监测子模块状态；如所述模块式直流耗能装置处于耗能状态，调节直流线路电压的控制目标，主动降低所述模块式直流耗能装置的直流线路电压稳定性能；
    步骤3：步骤2过程中如发生子模块非通讯故障，则由主控制系统或子模块控制系统下发旁路命令；
    步骤4：步骤2过程中如发生子模块通讯故障，则子模块控制系统离线方式下通过控制功率半导体器件的开通关断，控制子模块电容电压稳定在预设范围内；
    步骤5：主控制系统累积记录旁路的子模块数量和通讯故障的子模块数量；
    步骤6：重复步骤2～5，当故障旁路子模块数量大于等于Z1或通讯故障的子模块数量大于等于Z2时，跳出本模式，进入下一个冗余模式。
  9. 根据权利要求1所述的模块式直流耗能装置故障冗余控制方法，其特征在于，所述四级冗余模式控制方法如下：
    步骤1：设定该模式下允许发生故障的子模块数量为W；
    步骤2：监测子模块状态；如所述模块式直流耗能装置处于耗能状态，将耗能电阻全部投入；
    步骤3：步骤2过程中如发生子模块故障，则由主控制系统或子模块控制系统下发旁路命令；
    步骤4：主控制系统累积记录旁路的子模块数量；
    步骤5：重复步骤2～4，当故障旁路子模块数量大于等于W，则跳 出本模式。
  10. 根据权利要求6～9中至少一项所述的模块式直流耗能装置故障冗余控制方法，其特征在于，当发生子模块控制系统对主控制系统的上行通讯故障时，主控制系统将同时增加旁路子模块数量和通讯故障子模块数量，子模块通讯故障包括所述上行通讯故障。
  11. 根据权利要求6～9中至少一项所述的模块式直流耗能装置故障冗余控制方法，其特征在于，处于待机状态时，执行自主均压策略，所述自主均压策略下，子模块控制系统通过控制功率半导体器件的开通、关断控制子模块电容电压在预设范围内。
  12. 根据权利要求2所述的模块式直流耗能装置的控制方法，其特征在于，所述旁路开关为高速机械开关或过压击穿功率半导体器件，或二者的组合；所述高速机械开关接受子模块控制系统的命令动作合闸；所述过压击穿功率半导体器件在承受过电压时击穿短路，使子模块被旁路。
  13. 根据权利要求2所述的模块式直流耗能装置的控制方法，其特征在于，主控制系统对下与子模块控制系统通讯方式为一对一的通讯方式，或一对多的主从通讯方式，或手拉手的环网通讯方式。
  14. 根据权利要2所述的模块式直流耗能装置的控制方法，其特征在于，所述外部控制系统为能够控制装置所在直流线路的直流电压或传输功率的换流器的控制系统。
  15. 根据权利要求6-9中至少一项所述的模块式直流耗能装置的控制方法，其特征在于，无故障子模块的功率半导体器件接受主控制系统的指令，执行开通或关断命令；通讯故障子模块的功率半导体器件接受子模块控制系统的指令，执行开通或关断命令。
  16. 根据权利要求6-9中至少一项所述的模块式直流耗能装置的控制方法，其特征在于，所述闭合旁路开关的方式包括：
    主控闭合：由主控制控制系统给出旁路命令，触发开关机构闭合；
    子模块闭合：通讯故障时，由子模控制系统给出旁路命令，触发开关机构闭合；
    被动闭合：通过硬件回路自动触发开关机构闭合；
    击穿闭合：通过过压击穿功率半导体器件在承受过电压时击穿短路。
  17. 根据权利要求8所述的模块式直流耗能装置的控制方法，步骤2中改变直流线路电压的控制目标具体方法包括：
    增加滞环控制环宽：如所述模块式直流耗能装置采用滞环控制方式控制直流线路电压，即将直流线路电压控制在高电压限值与低电压限值之间，则增加高电压限值与低电压限值的差；
    增加闭环控制目标值：如所述模块式直流耗能装置采用直流线路电压闭环调节的方式，则提高直流线路电压控制目标值。
  18. 根据权利要求7所述的模块式直流耗能装置的控制方法，步骤6中当旁路的子模块数量和通讯故障的子模块数量总和大于等于预先设定总数限值YN时，也会跳出本模式，进入下一模式，其中所述YN≤Y1+Y2。
  19. 根据权利要求7所述的模块式直流耗能装置的控制方法，步骤6中当旁路的子模块数量和通讯故障的子模块数量总和大于等于预先设定总数限值ZN时，也会跳出本模式，进入下一模式，其中所述ZN≤Z1+Z2。
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