CN114865899A - Fault protection method and system for MMC sub-module - Google Patents

Fault protection method and system for MMC sub-module Download PDF

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Publication number
CN114865899A
CN114865899A CN202210443529.5A CN202210443529A CN114865899A CN 114865899 A CN114865899 A CN 114865899A CN 202210443529 A CN202210443529 A CN 202210443529A CN 114865899 A CN114865899 A CN 114865899A
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igct device
sub
control unit
turn
fault
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赵彪
余占清
曾嵘
白睿航
崔彬
屈鲁
汤雪腾
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Tsinghua University
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Tsinghua University
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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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

Abstract

The invention discloses a fault protection method and a fault protection system for an MMC sub-module, wherein the fault protection method comprises the following steps: the control unit sends a turn-off instruction or a turn-on instruction to the IGCT device of the sub-module; the IGCT device executes turn-off according to a turn-off instruction of the control unit, judges the turn-off state of the IGCT device, and sends a turn-off failure signal to the control unit after the turn-off failure; after the control unit receives the shutdown failure signal, locking the sub-module; after the sub-modules are locked, the IGCT device which fails to be turned off determines the fault of the IGCT device and sends the fault determination result to the control unit; and the control unit receives the fault determination result and bypasses the sub-module or unlocks the sub-module according to the fault determination result. When the invention detects that the IGCT device is in failure, the sub-module is locked in time, so that other IGCT devices are prevented from being switched on, and the fault spreading is effectively prevented; the method can judge whether the fault is the false alarm caused by the interference or not in a self-detection mode, reduce the probability of the sub-module false alarm fault and prolong the maintenance period of the converter valve.

Description

Fault protection method and system for MMC sub-module
Technical Field
The invention belongs to the technical field of power electronics, and particularly relates to a fault protection method and system for an MMC sub-module.
Background
The direct current transmission technology has attracted extensive attention due to the advantages of good electric energy quality, large transmission capacity, high system stability, convenience for distributed energy access and the like. The converter is a core component of the direct current transmission technology, and the performance of the converter directly influences whether the direct current transmission technology can be popularized and applied on a large scale. The Modular Multilevel Converter (MMC) has a good application prospect in the dc power transmission technology due to its outstanding advantages of high electric energy quality, good reliability, high output waveform quality, low power loss, etc. At present, an Insulated Gate Bipolar Transistor (IGBT) is adopted as a main power switch device of the MMC, and the IGBT has the characteristics of easiness in driving, large peak current capacity, self-turn-off, high switching frequency and the like. Compared with an IGBT, an Integrated Gate-Commutated Thyristor (IGCT) has the advantages of lower on-state voltage drop, higher reliability, lower manufacturing cost, compact structure, higher blocking voltage and higher through-current capability, and is expected to remarkably improve the performance of a voltage control type device in the application of a high-voltage high-capacity flexible direct-current power transmission MMC converter valve.
However, the IGCT devices are different from IGBTs and do not have a desaturation effect, and the fault current turn-off capability of the IGCT devices is far smaller than that of the IGBTs, so that when the IGCT devices are applied to the MMC sub-module, after one IGCT device is turned off and fails, once the other IGCT device opposite to the IGCT device is turned on, 100 kA-level fault surge current which cannot be turned off is generated, the sub-module is damaged, and greater loss is caused.
Disclosure of Invention
Aiming at the problems, the invention provides a fault protection method and a fault protection system for an MMC sub-module, which can prevent the sub-module from generating surge current to damage the sub-module after any IGCT device is turned off and fails.
A fault protection method of an MMC sub-module comprises the following steps: the control unit sends a turn-off instruction or a turn-on instruction to the IGCT device of the sub-module; the IGCT device executes turn-off according to a turn-off instruction of the control unit, judges the turn-off state of the IGCT device, and sends a turn-off failure signal to the control unit after the turn-off failure; after the control unit receives the shutdown failure signal, locking the sub-module; after the sub-modules are locked, the IGCT device which fails to be turned off determines the fault of the IGCT device and sends the fault determination result to the control unit; and the control unit receives the fault determination result and bypasses the sub-module or unlocks the sub-module according to the fault determination result.
Further, the IGCT device determining the turn-off state thereof includes the following steps:
and the IGCT device monitors the self anode current after the switching-off, and if the self anode current does not decrease, the switching-off failure is determined.
Further, the failure determination of the IGCT device which fails to turn off the IGCT device comprises the following steps:
after the IGCT device which fails to be turned off fails for a first set time, determining the reason of the failure to be turned off as detection interference or the failure of the IGCT device according to the gate electrode voltage and the cathode voltage of the IGCT device;
and if the failure reason of the IGCT device with failure shutdown is detected to be interference, the IGCT device with failure shutdown drives the IGCT device to perform self-checking, and the normal or failure of the IGCT device is determined.
Further, if it is determined that the failure cause of the IGCT device with failure shutdown is detection interference, the IGCT device with failure shutdown drives the IGCT device to perform self-checking, and determining that the IGCT device is normal or has a failure specifically is:
and driving the IGCT device which fails to be turned off to perform one-time turning-on triggering, turning off after the IGCT device is turned on for a second set time, if the turning-on and turning-off processes are normal, determining that the IGCT device which fails to be turned off is normal, and if an abnormal signal occurs in the turning-on or turning-off processes, determining that the IGCT device which fails to be turned off is in a fault.
Furthermore, the second set time is greater than or equal to the nominal shortest turn-on time of the IGCT device.
Further, the step of receiving the fault determination result by the control unit and bypassing or unlocking the sub-module according to the fault determination result is specifically as follows:
if the control unit receives the IGCT device fault determination signal with failed turn-off, the control unit controls a bypass switch of the sub-module to be closed, and the sub-module is bypassed; and if the control unit receives the fault release signal, the control unit controls the sub-module to recover the normal running state.
Further, the method for protecting the fault of the MMC sub-module further comprises the following steps:
and the valve-level control system sends a switching instruction to the control unit, and the control unit receives the switching instruction and generates a turn-off instruction or a turn-on instruction according to the switching instruction.
Further, the fault protection method of the MMC sub-module further comprises the following steps:
the control unit sends the fault determination result of the submodule to the valve-level control system.
Further, the sub-modules are half-bridge modules, full-bridge modules or clamped bridge modules.
The embodiment of the invention also provides a fault protection system of the MMC sub-module, which comprises a control unit and the sub-module, wherein the sub-module comprises a plurality of IGCT devices; the control unit is used for sending a turn-off instruction or a turn-on instruction to the IGCT device of the sub-module; the IGCT device is used for executing turn-off according to a turn-off instruction of the control unit, judging the turn-off state of the IGCT device, and sending a turn-off failure signal to the control unit after the turn-off failure; the control unit is also used for locking the sub-modules after receiving the shutdown failure signal; the IGCT device which fails to be turned off is used for carrying out fault determination on the IGCT device after the submodule is locked, and sending a fault determination result to the control unit; and the control unit is also used for receiving the fault determination result and bypassing the sub-module or unlocking the sub-module according to the fault determination result.
Further, the IGCT device with failed turn-off is specifically configured to:
after the IGCT device which fails to be turned off fails for a first set time, determining the reason of the failure to be turned off as detection interference or the failure of the IGCT device according to the gate electrode voltage and the cathode voltage of the IGCT device;
and if the failure reason of the IGCT device with failure shutdown is detected to be interference, the IGCT device with failure shutdown drives the IGCT device to perform self-checking, and the normal or failure of the IGCT device is determined.
Further, if it is determined that the failure cause of the IGCT device with failure shutdown is detection interference, the IGCT device with failure shutdown drives the IGCT device to perform self-checking, and determining that the IGCT device is normal or has a failure specifically is:
and driving the IGCT device which fails to be turned off to perform one-time turning-on triggering, turning off after the IGCT device is turned on for a second set time, if the turning-on and turning-off processes are normal, determining that the IGCT device which fails to be turned off is normal, and if an abnormal signal occurs in the turning-on or turning-off processes, determining that the IGCT device which fails to be turned off is in a fault.
Further, the fault protection system of the MMC sub-module further includes: and the valve-level control system is used for sending a switching instruction to the control unit and receiving a fault determination result of the sub-module sent by the control unit.
Further, the sub-modules are half-bridge modules, full-bridge modules or clamped bridge modules.
The invention has the beneficial effects that:
1. when the invention detects that the IGCT device is in failure, the sub-module is locked in time, and the other IGCT device is prevented from being switched on, thereby effectively preventing the fault from spreading.
2. The method can judge whether the fault is the false alarm caused by the interference or not in a self-detection mode, reduce the probability of the sub-module false alarm fault and prolong the maintenance period of the converter valve.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 shows a fault protection system signaling link diagram of an MMC sub-module according to an embodiment of the present invention;
fig. 2 is a schematic flowchart illustrating a method for fault protection of an MMC sub-module according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a fault protection method and a fault protection system for an MMC sub-module, aiming at the MMC application, after an IGCT device is cut off and fails, the module can be locked in time, the IGCT device opposite to the module is prevented from being turned on, and the fault spreading is effectively prevented. And whether the fault is false alarm caused by interference can be judged in a self-detection mode, the probability of false alarm fault is reduced, and the maintenance period of the converter valve is prolonged.
To facilitate an understanding of the embodiments of the present application, the following briefly describes an IGCT device:
an Integrated Gate Commutated Thyristor (IGCT) is a novel switching device for a large-capacity power electronic device, and mainly comprises a GCT chip packaged inside a tube shell and a drive integrated outside the tube shell. The IGCT driver mainly undertakes the function of receiving the communication signal of the upper control system and converting the communication signal into a voltage current signal for turning on and off the GCT chip.
The fault protection method and the fault protection system for the MMC sub-module are suitable for a half-bridge module, a full-bridge module, a clamping bridge module and the like which take an IGCT (integrated gate commutated thyristor) as a full-control device.
Referring to fig. 1, fig. 1 shows a signaling link diagram of a fault protection system of an MMC sub-module according to an embodiment of the present invention.
The utility model provides a fault protection system of MMC submodule piece, includes submodule piece and control unit, and the submodule piece includes a plurality of IGCT devices and bypass switch, and the gate drive of a plurality of IGCT devices passes through optic fibre and control unit communication connection, and the control unit still is connected with bypass switch.
And the control unit is used for sending a turn-off instruction or a turn-on instruction to the IGCT device.
And the IGCT device is used for executing turn-off according to the turn-off instruction of the control unit, judging the turn-off state of the IGCT device, and sending a turn-off failure signal to the control unit after the turn-off failure.
And the control unit is also used for locking the submodule after receiving the shutdown failure signal.
And the IGCT device which fails to be turned off is used for carrying out fault determination on the IGCT device after the submodule is locked, and sending a fault determination result to the control unit.
And the control unit is also used for receiving the fault determination result and controlling the bypass switch to close or release the locking of the sub-module according to the fault determination result.
Illustratively, the control unit is an in-situ control panel, with which one or more IGCT devices can be controlled.
Illustratively, the sub-modules include an electrolytic capacitor, an inductor L s Resistance R s Capacitor C s A first diode D 1 A second diode D 2 And a third diode D s First IGCT device T 1 A second IGCT device T 2 And a bypass switch.
Wherein, the positive electrode of the electrolytic capacitor and the inductor L s First terminal, resistor R s First end connected to inductor L s Second terminal and third diode D s Anode, first IGCT device T 1 Anode, first diode D 1 Cathode connection, third diode D s Cathode and resistor R s Second terminal, capacitor C s The first end of the first connecting rod is connected,capacitor C s A second end connected with the cathode of the electrolytic capacitor and a second IGCT device T 2 Cathode, second diode D 2 The anode is connected with the first end of the bypass switch, and the first IGCT device T 1 Cathode and first diode D 1 Anode, second IGCT device T 2 Anode, second diode D 2 The cathode is connected with the second end of the bypass switch.
The local control board is connected with the first IGCT device T through optical fibers 1 Gate drive, second IGCT device T 2 Is connected to the gate drive.
The local control board is used for controlling the on-off of the bypass switch and receiving the first IGCT device T 1 And a second IGCT device T 2 And a gate cathode voltage signal, while it can latch the first IGCT device T 1 And a second IGCT device T 2 。
It should be noted that the sub-module according to the embodiment of the present invention is an exemplary illustration in which the IGCT device is a fully controlled device.
Further, when the sub-module is applied to a converter valve, the fault protection system of the MMC sub-module further includes a valve-level control system, and the valve-level control system is connected with the control unit through an optical fiber.
And the valve-level control system is used for sending a switching instruction to the control unit.
The control unit is also used for receiving the switching instruction and controlling the IGCT device to be switched off or on according to the control instruction; and the sub-module is also used for sending the fault determination result of the sub-module to the valve-level control system.
Referring to fig. 2, fig. 2 is a schematic flowchart illustrating a method for protecting a fault of an MMC sub-module according to an embodiment of the present invention.
The embodiment of the invention also provides a fault protection method of the MMC sub-module, which comprises the following steps:
and S1, the control unit sends a turn-off instruction or a turn-on instruction to the IGCT device.
And S2, the IGCT device executes turn-off according to the turn-off instruction of the control unit, the IGCT device judges the turn-off state of the IGCT device, and after the turn-off fails, the IGCT device sends a turn-off failure signal to the control unit.
Specifically, the IGCT device for judging the turn-off state of the IGCT device comprises the following steps:
the IGCT device monitors the anode current of the IGCT device after the IGCT device is turned off, and if the anode current of the IGCT device does not drop, the IGCT device determines that the IGCT device is turned off.
For example, the monitoring of the anode current of the switched-off IGCT device may be performed by providing a current coil at the anode of the IGCT device, or by driving and detecting the voltage drop of the turn-off circuit at the gate of the IGCT device, which is implemented in the prior art and is not described herein again.
It should be noted that after the IGCT device is turned off, the anode of the IGCT device should have no current, and if the current existing at the anode of the IGCT device can still be detected after the turn-off time, the IGCT device is in a short-circuit state, and at this time, the turn-off failure of the IGCT device can be determined, and the IGCT device can report a turn-off failure signal to the control unit through the optical fiber.
And S3, locking the sub-modules after the control unit receives the shutdown failure signal.
Specifically, the locking sub-module is a control unit which does not send an opening instruction to any IGCT device in the sub-modules any more.
The control unit receives the IGCT device turn-off failure signal and does not trigger the IGCT device opposite to the IGCT device to turn on, so that the phenomenon that a capacitor is short-circuited by one IGCT device which fails to turn off and a newly-turned-on IGCT device to cause fault surge current is avoided.
And S4, after the sub-modules are locked, the IGCT device which fails to be turned off determines the fault of the IGCT device, and sends the fault determination result to the control unit.
Specifically, the step of determining the fault of the IGCT device which fails to turn off includes the following steps:
and S41, determining the reason of the failure of the IGCT device due to detection interference or the failure of the IGCT device according to the gate and cathode voltages of the IGCT device after the IGCT device fails to turn off for a first set time.
The first setting time can be adaptively set, and the first setting time is reserved for providing the time for the voltage reduction of the gate cathode, so that the condition that the test value is not accurate enough due to short-time test is avoided.
For example, the first set time is 10ms, after the IGCT device fails to turn off for the first set time, the gate and cathode voltages of the IGCT device are detected, if the absolute value of the voltage is higher than the fault threshold, the IGCT device determines that the IGCT device fails to turn off as the detection interference, and if the absolute value of the voltage is lower than the fault threshold, the IGCT device determines that the IGCT device fails to turn off.
It should be noted that, because the current detection is prone to be interfered, the reason for the failure of the IGCT device needs to be further determined to avoid the false alarm of the fault. If the reason of the failure of the turn-off is that the turn-off function of the IGCT device fails, the chip of the IGCT device is internally short-circuited, and the turn-off capacitor bank driven by the IGCT device discharges through the short-circuited chip, so that the absolute values of the gate and cathode voltages are continuously reduced, and the absolute values are lower than the fault threshold value after a period of time. The signal is more stable and suitable for fault determination. If the failure threshold is lower, it can be determined that the chip is damaged.
And S42, if the failure reason of the IGCT device with failure shutdown is determined to be detection interference, the IGCT device with failure shutdown drives the IGCT device to perform self-checking, and the fact that the IGCT device is normal or fails is determined.
In an example, the IGCT device with failed turn-off drives itself to perform one turn-on trigger, and turns off after the turn-on lasts for a second set time, if the turn-on and turn-off processes are normal, the IGCT device with failed turn-off is determined to be normal, and if an abnormal signal occurs in the turn-on or turn-off process, the IGCT device with failed turn-off is determined to be in a fault.
Specifically, the second set time is greater than or equal to the nominal shortest on-time of the IGCT device, and is illustratively 100 us.
It should be noted that when the absolute value of the gate cathode voltage is higher than the above-mentioned fault threshold, there is a possibility that an error or disturbance occurs in detecting the off state of the IGCT device, and there is a possibility that the IGCT device is in a high resistance state after being damaged. At this time, further determination is needed to eliminate the situation that the IGCT device is damaged but is in a high-resistance state after being damaged, and the discharge of the driving turn-off capacitor bank is slow.
On the basis of determining that the failure reason of turn-off is caused by detection interference, the IGCT device which fails to turn off turns on and turns off the IGCT device for one more time, wherein the time length is more than or equal to the nominal shortest turn-on time of the IGCT device, so that the influence on the operation of the converter valve is reduced. And if the on and off are normal, determining that the off failure signal of the IGCT device belongs to false alarm. In the process, as the sub-module is in a locking state and the other IGCT devices in the sub-module are in an off state, large fault current of short circuit of the capacitor can not be caused.
And S5, the control unit receives the fault determination result and bypasses the sub-module or unlocks the sub-module according to the fault determination result.
Specifically, the IGCT device that failed to turn off sends an IGCT device failure determination signal or a failure release signal to the control unit through the optical fiber.
And if the control unit receives the fault determination signal of the IGCT device which fails to be turned off, the control unit controls the bypass switch to be closed to bypass the sub-module. And if the control unit receives the fault release signal, the control unit controls the sub-module to recover the normal running state.
Further, before step S1, the method for protecting the MMC sub-module from faults further includes the following steps:
and S0, the valve-level control system sends a switching instruction to the control unit, and the control unit receives the switching instruction and generates a turn-off instruction or a turn-on instruction according to the switching instruction.
Further, the method for protecting the fault of the MMC sub-module further includes the following steps after step S5:
and S6, the control unit sends the fault determination result of the submodule to the valve-level control system.
It should be noted that the dead zone of the sub-module in the embodiment of the present application is not less than the turn-off delay of the IGCT device, the failure determination delay of the IGCT device, and the failure determination delay of the control unit, so as to ensure that the module can be locked in time after the turn-off failure, and the dead zone of the sub-module refers to the delay from the turn-off of one IGCT device to the turn-on of another IGCT device in the normal working state.
For the understanding of the embodiments of the present application, the failure of the sub-module first IGCT device T1 will be taken as an example to describe the fault protection method disclosed in the present application in more detail.
The valve-level control system sends a switching instruction to the control unit, the control unit receives the switching instruction, and controls the first IGCT device T in the submodule according to the control instruction 1 Off, first IGCT device T 1 Does not decrease the anode current of the first IGCT device T 1 The shutdown failure signal is sent to the control unit through the optical fiber, and the control unit receives the first IGCT device T 1 After the failure signal is turned off, the submodule is locked immediately, namely the second IGCT device T is not triggered after the dead zone 2 And (4) opening.
Consider the first IGCT device T 1 Internal delay, first IGCT device T 1 And after the first set time of the turn-off failure, detecting the gate voltage and the cathode voltage of the self, if the voltage is abnormal, determining the self fault, sending the fault determination result to the control unit, and controlling the bypass switch to be closed by the control unit to bypass the sub-module and sending the fault determination result to the valve-level control system.
The first IGCT device T1 detects the gate and cathode voltages after failing to turn off for a first set time, and if the voltages are normal, the first IGCT device T 1 Self-triggering for a short time, detecting the fault in the whole triggering process, and determining the first IGCT device T if the triggering process is normal 1 And if no fault exists, determining that the fault is mistakenly reported, and releasing the locking state of the sub-module by the control unit. If the first IGCT device T 1 And if the switching-on triggering process is determined to be abnormal, determining the self fault, sending the fault determining result to the control unit, and controlling the bypass switch to be closed by the control unit to bypass the sub-module and sending the fault determining result to the valve level control system by the control unit.
The fault protection method for the MMC sub-module provided by the embodiment of the invention is realized based on the control of an IGCT device, and is suitable for the sub-module taking the IGCT device as a full-control device, such as a half-bridge module, a full-bridge module or a clamping bridge module taking the IGCT device as the full-control device.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (14)

1. A fault protection method of an MMC sub-module is characterized by comprising the following steps:
the control unit sends a turn-off instruction or a turn-on instruction to the IGCT device of the sub-module;
the IGCT device executes turn-off according to a turn-off instruction of the control unit, judges the turn-off state of the IGCT device, and sends a turn-off failure signal to the control unit after the turn-off failure;
after the control unit receives the shutdown failure signal, locking the sub-module;
after the sub-modules are locked, the IGCT device which fails to be turned off determines the fault of the IGCT device and sends the fault determination result to the control unit;
and the control unit receives the fault determination result and bypasses the sub-module or unlocks the sub-module according to the fault determination result.
2. The fault protection method according to claim 1, wherein the determining of the self-shutdown state by the IGCT device comprises the steps of:
the IGCT device monitors the anode current of the IGCT device after the IGCT device is turned off, and if the anode current of the IGCT device does not drop, the IGCT device determines that the IGCT device is turned off.
3. The fault protection method according to claim 1, wherein the determining that the IGCT device failed to turn off has failed to perform the fault determination on itself comprises the steps of:
after the IGCT device which fails to be turned off fails for a first set time, determining the reason of the failure to be turned off as detection interference or the failure of the IGCT device according to the gate electrode voltage and the cathode voltage of the IGCT device;
and if the failure reason of the IGCT device with failure shutdown is determined to be detection interference, the IGCT device with failure shutdown drives the IGCT device to perform self-detection, and the fact that the IGCT device is normal or fails is determined.
4. The fault protection method according to claim 3, wherein if it is determined that the failure cause of the IGCT device with failed shutdown is detection interference, the IGCT device with failed shutdown drives itself to perform self-test, and the determining that itself is normal or has a fault specifically comprises:
and driving the IGCT device which fails to be turned off to perform one-time turning-on triggering, turning off after the IGCT device is turned on for a second set time, if the turning-on and turning-off processes are normal, determining that the IGCT device which fails to be turned off is normal, and if an abnormal signal occurs in the turning-on or turning-off processes, determining that the IGCT device which fails to be turned off is in a fault.
5. The fault protection method of claim 4, wherein the second set time is equal to or greater than a nominal minimum on-time of the IGCT device.
6. The fault protection method according to claim 1, wherein the control unit receives the fault determination result and bypasses the sub-module or unlocks the sub-module according to the fault determination result, specifically:
if the control unit receives the IGCT device fault determination signal with failed turn-off, the control unit controls a bypass switch of the sub-module to be closed, and the sub-module is bypassed; and if the control unit receives the fault release signal, the control unit controls the sub-module to recover the normal running state.
7. The fault protection method according to any one of claims 1 to 6, wherein the fault protection method of the MMC sub-module further comprises the steps of:
and the valve-level control system sends a switching instruction to the control unit, and the control unit receives the switching instruction and generates a turn-off instruction or a turn-on instruction according to the switching instruction.
8. The fault protection method according to claim 7, wherein the fault protection method of the MMC sub-module further comprises the steps of:
the control unit sends the fault determination result of the submodule to the valve-level control system.
9. The fault protection method according to any one of claims 1 to 6, wherein the sub-modules are half-bridge modules, full-bridge modules or clamped-bridge modules.
10. The fault protection system of the MMC sub-module is characterized by comprising a control unit and the sub-module, wherein the sub-module comprises a plurality of IGCT devices;
the control unit is used for sending a turn-off instruction or a turn-on instruction to the IGCT device of the sub-module;
the IGCT device is used for executing turn-off according to a turn-off instruction of the control unit, judging the turn-off state of the IGCT device, and sending a turn-off failure signal to the control unit after the turn-off failure;
the control unit is also used for locking the sub-modules after receiving the shutdown failure signal;
the IGCT device which fails to be turned off is used for carrying out fault determination on the IGCT device after the submodule is locked, and sending a fault determination result to the control unit;
and the control unit is also used for receiving the fault determination result and bypassing the sub-module or unlocking the sub-module according to the fault determination result.
11. The fault protection system of claim 10, wherein the failed-shutdown IGCT device is specifically configured to:
after the IGCT device which fails to be turned off fails for a first set time, determining the reason of the failure to be turned off as detection interference or the failure of the IGCT device according to the gate electrode voltage and the cathode voltage of the IGCT device;
and if the failure reason of the IGCT device with failure shutdown is detected to be interference, the IGCT device with failure shutdown drives the IGCT device to perform self-checking, and the normal or failure of the IGCT device is determined.
12. The fault protection system according to claim 11, wherein if it is determined that the failure cause of the IGCT device that fails to turn off is detection interference, the IGCT device that fails to turn off drives itself to perform self-checking, and determining that itself is normal or faulty specifically is:
and driving the IGCT device which fails to be turned off to perform one-time turning-on triggering, turning off after the IGCT device is turned on for a second set time, if the turning-on and turning-off processes are normal, determining that the IGCT device which fails to be turned off is normal, and if an abnormal signal occurs in the turning-on or turning-off processes, determining that the IGCT device which fails to be turned off is in a fault.
13. The fault protection system according to any one of claims 10-12, wherein the fault protection system further comprises: and the valve-level control system is used for sending a switching instruction to the control unit and receiving a fault determination result of the sub-module sent by the control unit.
14. The fault protection system of any one of claims 10-12, wherein the sub-modules are half-bridge modules, full-bridge modules or clamped-bridge modules.
CN202210443529.5A 2022-04-26 2022-04-26 Fault protection method and system for MMC sub-module Pending CN114865899A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115149939A (en) * 2022-09-01 2022-10-04 清华大学 Discrete high-voltage electronic device and method

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115149939A (en) * 2022-09-01 2022-10-04 清华大学 Discrete high-voltage electronic device and method

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