CN112039361A - MMC sub-module and MMC latch-free low-voltage fault ride-through method applying same - Google Patents

MMC sub-module and MMC latch-free low-voltage fault ride-through method applying same Download PDF

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CN112039361A
CN112039361A CN202010924267.5A CN202010924267A CN112039361A CN 112039361 A CN112039361 A CN 112039361A CN 202010924267 A CN202010924267 A CN 202010924267A CN 112039361 A CN112039361 A CN 112039361A
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CN112039361B (en
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王毅
陶建业
王琛
谭开东
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North China Electric Power 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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/487—Neutral point clamped inverters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/001—Methods to deal with contingencies, e.g. abnormalities, faults or failures
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]

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Abstract

The invention provides a Diode Clamping Hybrid Submodule (DCHSM) of an MMC and a control method for the MMC latch-free low-voltage fault ride-through by applying the same, wherein the DCHSM comprises a half-bridge-full-bridge hybrid submodule (HB-FBSM) and a clamping diode; the cathode of the clamping diode is connected with the anode of the capacitor of the half-bridge submodule of the HB-FBSM, and the anode of the clamping diode is connected with the anode of the capacitor of the full-bridge submodule of the HB-FBSM. The DCHSM has fault current clearing capacity and negative level output capacity, and when the voltage on the direct current side of the MMC slightly drops, the MMC operates in a low-voltage state to maintain power transmission; when a bipolar short-circuit fault occurs, the voltage on the direct current side drops seriously, and the MMC locks all the sub-modules to realize the quick clearing of fault current.

Description

MMC sub-module and MMC latch-free low-voltage fault ride-through method applying same
Technical Field
The invention belongs to the technical field of power electronics, and discloses an MMC sub-module and an MMC latch-free low-voltage fault ride-through method applying the same.
Background
With the rapid development of distributed energy and direct current transmission technologies, various current conversion methods are proposed in succession. Modular Multilevel Converters (MMC) have gained much attention because of their advantages such as good expansibility, low harmonic content, high transmission efficiency, flexible control, etc.
In order to cope with transient faults frequently occurring in an overhead direct current transmission line, the following three solutions are mainly selected at present: the use of ac circuit breakers, the use of dc circuit breakers and the use of new sub-modules with fault current clearing capability. The ac circuit breaker cannot cope with a transient fault well because the system recovery operation time is long, and the dc circuit breaker cannot be used for cutting off a large fault current because its technology is immature. Therefore, scholars at home and abroad carry out a great deal of research on novel sub-modules with fault current clearing capability and put forward a plurality of new sub-module topology schemes.
The existing sub-modules with fault current clearing capability can be roughly divided into two types, namely a device reverse blocking type and a capacitance reverse voltage blocking type. The capacitance back pressure blocking type can be divided into a single-capacitance sub-module and a double-capacitance sub-module. The single-capacitor sub-module is added with devices on the basis of a half bridge, so that the single-capacitor sub-module has a fault current clearing capability, such as a full bridge sub-module (FBSM), a diode clamp sub-module (DCSM), a quasi-full bridge sub-module (SFBSM), a single clamp sub-module (CSSM), and a diode clamp sub-module (DCBSSM) with a bidirectional switch. The number of IGBTs required by the unit level output of the single-capacitor submodule is certainly larger than 2, and the number of DCSMs with the minimum number also needs 2.5. The dual-capacitor sub-module is obtained by adding devices on the basis of two half bridges or a half bridge and a full bridge, such as a diode clamped dual sub-module (DCDSM), a clamped dual sub-module (CDSM), an enhanced Hybrid sub-module (EHSM), a Hybrid sub-module (Hybrid SM), a diode clamped multi-level sub-module (DCMSM), an asymmetric dual sub-module (ADCC), a five-level cross-connected sub-module (FLCSM), a serial connected dual sub-module (SDSM), and the like. Most of the devices do not have fault current symmetrical clearing capability after being locked, namely the blocking voltage is +2Uc when the current is forward after being locked, and the blocking voltage is-Uc when the current is reverse. Table 1 compares the device count and fault current clearing capability of several typical MMC sub-module topologies.
Table 1 existing MMC sub-module topology
Figure BDA0002667778400000021
From the aspects of the number of used devices and the fault current clearing capability, the single-capacitor sub-modules with better performance in the existing topology are single-clamping sub-modules (CSSM) and full-bridge-like sub-modules (SFBSM), and the double-capacitor sub-modules with better performance are series double sub-modules (SDSM). The three parts all have fault current symmetrical clearing capacity, and the number of the IGBTs required by the unit capacitor is respectively 3, 3 and 2.5. Since IGBTs of equal withstand voltage capability are much more expensive than diodes, the number of IGBTs required for a unit capacitance of a submodule is of major concern from the aspect of investment cost.
Above-mentioned novel submodule piece does not possess negative level output ability mostly, and direct current side fault current can only be cut off through the mode of shutting down the submodule piece after the short circuit fault takes place for the direct current side, and power transmission is interrupted this moment, is unfavorable for the transient stability of system.
Disclosure of Invention
In order to ensure that the MMC converter station can realize low-voltage operation after voltage drop occurs on a direct current side or can be used as a STATCOM to provide reactive power and voltage support for an alternating current side, the invention provides a self-voltage-sharing current-limiting type MMC submodule with negative level output capacity, namely a Diode Clamped Hybrid Submodule (DCHSM), and provides an MMC no-locking type low-voltage fault ride-through method applying the submodule.
In one aspect, the invention provides a diode-clamped hybrid submodule (DCHSM) for an MMC, wherein the DCHSM comprises a half-bridge-full-bridge hybrid submodule (HB-FBSM) and a clamping diode; the cathode of the clamping diode is connected with the anode of the capacitor of the half-bridge submodule of the HB-FBSM, and the anode of the clamping diode is connected with the anode of the capacitor of the full-bridge submodule of the HB-FBSM.
Further, after the DCHSM is locked, the clamping diode introduces a fault current into the capacitor of the half-bridge sub-module of the HB-FBSM, the fault current charges the capacitor of the half-bridge sub-module of the HB-FBSM and the capacitor of the full-bridge sub-module of the HB-FBSM in parallel, and the voltage of the internal capacitor of the DCHSM is kept balanced during locking.
On the other hand, the invention provides an MMC latch-free low-voltage fault ride-through method of a diode-clamped hybrid submodule (DCHSM) of an MMC, which is applied, and is characterized in that when the direct-current side voltage of the MMC slightly drops, for a certain phase:
when the DCHSM bridge arm current ism>When 0, 2N measured capacitance voltage numbers are sequenced from low to high to form a sequence X1Sequencing voltage signals of capacitors of a full-bridge submodule of HB-FBSM from N DCHSM submodules from high to low to form a sequence X2If the number of capacitors N is put into the bridge arm in the normal statep>NdPositive input sequence X1Middle front Np-NdA capacitor; if N is presentp<NdTime, negative input sequence X2Middle front Nd-NpA capacitor;
when bridge arm current ism<When 0, 2N measured capacitance voltage signals are sequenced from high to low to form a sequence X3Sequencing voltage signals of capacitors of HB-FBSM full-bridge submodule in N DCHSM submodules from low to high to form a sequence X4If the number of capacitors N is put into the bridge arm in the normal statep>NdPositive input sequence X3Middle front Np-NdA capacitor; if N is presentp<NdTime, negative input sequence X4Middle front Nx-NpA capacitor.
Has the advantages that: the invention provides a diode clamping mixed submodule with fault current clearing capability and negative level output capability(DCHSM). On one hand, the voltage modulation ratio of the MMC can be improved under the steady-state operation, and an alternating current side can be accessed to an alternating current power grid with higher voltage grade under the condition that the voltage of the direct current side is not changed; on the other hand, the fault current during latching is applied to the capacitor C1And C2And the parallel charging is carried out, so that the energy balance of the capacitors in the bridge arms can be realized, and the quick restart of the system is facilitated. A no-lock low-voltage fault ride-through method is provided for the negative level output capability of the DCHSM. When the voltage of the direct current side slightly drops, the MMC converter operates in a low-voltage state to maintain power transmission. When a bipolar short-circuit fault occurs, the voltage on the direct current side drops seriously, the MMC converter locks all the sub-modules, and the fault current is cleared quickly.
Drawings
FIG. 1(a) is a HB-FBSM submodule diagram;
FIG. 1(b) is a diagram of the DCHSM submodule of the present invention;
FIG. 2 shows the current path of the DCHSM submodule of the present invention in 6 operation modes, wherein FIGS. 2(a) and 2(b) are i in mode 1sm>0 and ism<Current path at 0; FIGS. 2(c) and 2(d) are views of i in mode 2sm>0 and ism<Current path at 0; FIGS. 2(e) and 2(f) are respectively i in mode 3sm>0 and ism<Current path at 0; FIGS. 2(g) and 2(h) are views of i in mode 4sm>0 and ism<Current path at 0; FIGS. 2(i) and 2(j) are views of i in mode 5sm>0 and ism<Current path at 0; FIGS. 2(k) and 2(l) are respectively i in mode 6sm>0 and ism<Current path at 0;
FIG. 3 is a low voltage fault ride through operational schematic;
FIG. 4 is a flow chart of a no-locking low-voltage fault ride-through method of an MMC converter station based on DCHSM of the present invention;
fig. 5 shows simulation results of the MMC converter station based on the DCHSM of the present invention after a double short circuit fault occurs on the dc side, wherein fig. 5(a) is an ac side voltage waveform; FIG. 5(b) shows a DC-side current waveform; FIG. 5(c) is a waveform of the capacitor voltage of the upper bridge arm of phase a;
fig. 6 shows simulation waveforms of the MMC converter station based on the DCHSM of the present invention after slight voltage drop on the dc side, where fig. 6(a) is a dc side current waveform of the MMC converter, fig. 6(b) is a dc side voltage waveform of the MMC converter, and fig. 6(c) is an ac side voltage waveform of the MMC converter.
Detailed Description
The embodiments are described in detail below with reference to the accompanying drawings.
A conventional half-bridge-full-bridge hybrid sub-module (HB-FBSM) is formed by connecting a half-bridge sub-module and a full-bridge sub-module in series. FIG. 1(a) shows the structure of an HB-FBSM. Wherein, the half-bridge sub-module consists of two diodes, two IGBTs and a capacitor (C)1) And (4) forming. The first IGBT (T)1) And a first diode (D)1) Reverse parallel connection to form a first switch and a second IGBT (T)2) And a second diode (D)2) And the reverse parallel connection forms a second switch. The first switch being in series with the second switch, i.e. D1And D2The cathodes of the two electrodes are connected; capacitor C1Positive electrode of (2) and (D)1Is connected to the cathode, C1And D2Are connected with each other. From D1Anode of (2) leading out a first output port O of the half-bridge submodule1Simultaneously formed by D2Second output port O of the anode lead-out half-bridge submodule2。
The full-bridge submodule consists of four diodes, four IGBTs and one capacitor (C)2) And (4) forming. The four IGBTs are respectively connected with the four diodes in reverse parallel to form a third switch, a fourth switch, a fifth switch and a sixth switch, which are the same as the half-bridge sub-module. The third switch and the fourth switch are in series relation, i.e. the third diode D3Anode of and a fourth diode D4The cathodes of the two electrodes are connected; the fifth switch being in series with the sixth switch, i.e. a fifth diode D5Anode of and a sixth diode D6The cathodes of the two electrodes are connected; capacitor C2Positive electrode of (2) and (D)3And D5Is connected to the cathode, C2And D4And D6Anode phase ofAnd (4) connecting. From D3Anode of the second sub-module is led out of a first output port O of the full-bridge sub-module1', simultaneously by D5Anode of the second output port of the full-bridge submodule2'. Second output port O of the half-bridge submodule is connected2And a first output port O of the full half-bridge submodule1', the topology of HB-FBSM is obtained.
The invention provides a Diode Clamped Hybrid Submodule (DCHSM) for an MMC (modular multilevel converter), which is formed by adding a clamping diode on the basis of HB-FBSM (high-performance back-ground fault current). Fig. 1(b) shows a specific embodiment of the DCHSM structure of the present invention. Clamping diode D7Is connected to the capacitor C1Anode of (2), diode D7Anode of is connected to the capacitor C2The positive electrode of (1). After the diode clamping hybrid submodule is locked, the clamping diode D7Introducing fault current into capacitor C1Medium, fault current to capacitance C1And C2Parallel charging is performed, and the voltage of the capacitor inside the submodule is kept balanced during locking.
Table 2 gives the switching state table of the DCHSM of the present invention. According to different trigger signals, the DCHSM has 6 switch states.
TABLE 2 DCHSM on-off state table
Figure BDA0002667778400000061
Working mode 1: when T is1、T3And T5Conduction, T2、T4And T6When turned off, the current path is as shown in FIGS. 2(a) and 2(b), ismTo the capacitor C1Charging or discharging a capacitor C2Is bypassed, the output voltage of the sub-module is UC1. When the bridge arm current is positive, ism>At 0, the current path is D1→C1→D3→T5(ii) a When bridge arm current is negative, ism<At 0, the current path is D5→T3→C1→T1。
The working mode 2 is as follows: when T is2、T3And T6Conduction, T1、T4And T5When turned off, the current path is as shown in FIGS. 2(c) and 2(d), ismTo the capacitor C2Charging or discharging a capacitor C1Is bypassed, the output voltage of the sub-module is UC2. When the bridge arm current is positive, ism>At 0, the current path is T2→D3→C2→D6(ii) a When bridge arm current is negative, ism<At 0, the current path is T6→C2→T3→D2。
Working mode 3: when T is1、T3And T6Conduction, T2、T4And T5When turned off, the current path is as shown in FIGS. 2(e) and 2(f), ismTo the capacitor C1And C2The output voltage of the sub-module is UC1+UC2. When the bridge arm current is positive, ism>At 0, the current path is D1→C1→D3→C2→D6(ii) a When bridge arm current is negative, ism<At 0, the current path is T6→C2→T3→C1→T1。
The working mode 4 is as follows: when T is2、T3And T5Conduction, T1、T4And T6When turned off, the current path is as shown in FIGS. 2(g) and 2(h), and the capacitor C1And C2Bypassed and the sub-module output voltage is 0. When the bridge arm current is positive, ism>At 0, the current path is T2→D3→T5(ii) a When bridge arm current is negative, ism<At 0, the current path is D5→T3→D2。
The working mode 5 is as follows: when T is2、T4And T5Conduction, T1、T3And T6When turned off, the current path is as shown in FIGS. 2(i) and 2(j), ismTo the capacitor C2Charging or discharging a capacitor C1Is bypassed, and the output voltage of the sub-module is-UC2. When the bridge arm current is positive, ism>At 0, the current path is T2→T4→C2→T5(ii) a When bridge arm current is negative, ism<At 0, the current path is D5→C2→D4→D2. In this mode, the MMC converter with the sub-module of the present invention has no latch-up low voltage fault ride through capability.
The working mode 6 is as follows: when all the switch tubes are turned off, the current path is as shown in FIGS. 2(k) and 2(l), ismTo the capacitor C1And C2Are charged in series. When the bridge arm current is positive, ism>At 0, the current path is D1→C1→D3→C2→D6Submodule output voltage of UC1+UC2(ii) a When bridge arm current is negative, ism<At 0, there are two paths for the current: the passage 1 is D5→D7→C1→D2Path 2 is D5→C2→D4→D2The output voltage of the submodule is- (U)C1//UC2). Fault current can be simultaneously applied to C1And C2The parallel charging is performed, so that the capacitor voltage is still balanced in the locked state.
When voltage drop occurs to the direct current side voltage, the direct current side current of the MMC converter station is rapidly increased due to capacitor discharge, and the voltage of the capacitor of the submodule is rapidly reduced, so that the aim of maintaining low-voltage operation after the voltage drop occurs to the direct current side is achieved by the MMC converter.
The key point of realizing fault ride-through after voltage drop occurs on the direct current side is to ensure the stability of the voltage on the alternating current side of the MMC converter. Voltage U of middle point of phase unit of MMC converter relative to equivalent grounding point O at direct current sidevjComprises the following steps:
Figure BDA0002667778400000081
DC side voltage UdcIs composed of
Udc＝Upj+Unj (2)
UpjAnd UnjRespectively j-phase upper and lower bridge arm voltages.
As shown in FIG. 3, when the DC side voltage drops by Δ UdcIn time, the upper and lower bridge arms in each phase unit respectively bear delta UdcThe voltage drop of/2 is shown by equation (1), and the ac side voltage remains unchanged. During the low-voltage fault ride-through period, the j-phase upper and lower bridge arm voltage and the alternating-current side voltage are respectively as follows:
Figure BDA0002667778400000082
Upj' and Unj' is j-phase upper and lower bridge arm voltage, U during low voltage fault ride throughvj' is the voltage of the middle point of the j-phase unit relative to the equivalent grounding point O on the direct current side during the low-voltage fault ride-through period.
As shown in fig. 2(i) and 2(j), that is, the DCHSM operation mode 5 of the present invention has a negative level output capability. The number N of the levels of the upper bridge arm and the lower bridge arm which need to be reduced according to the difference of the DC voltage drop degreesdAnd are also different.
Figure BDA0002667778400000083
In the formula, Δ UdcIs the voltage drop of the DC side, UCNIs the sub-module capacitance voltage rating.
Under the normal operation state, the input capacitance number N of the j-phase upper bridge arm and the j-phase lower bridge armpjAnd NnjModulating wave voltage U by j-phase upper and lower bridge armspjSum of UnjAnd (4) determining.
Figure BDA0002667778400000091
When the voltage on the DC side drops by delta UdcThen, the level numbers of the upper and lower bridge arms are reduced by Nd. At this time, the DC side voltage of the MMC converter is reduced by delta UdcWhile maintaining the AC side voltageAnd is not changed.
The invention provides a latch-free low-voltage fault ride-through control method of an MMC converter applying the DCHSM, which is disclosed by the invention, by combining two methods of reducing the negative level output characteristic of the DCHSM and reducing the number of input sub-modules. Taking the upper bridge arm of the phase a as an example, under the normal operation state, the number of capacitors put into the bridge arm is NpaThe flow of the no-lock fault ride-through control method is shown in fig. 4.
When bridge arm current ism>When 0, 2N measured capacitance voltage signals are sequenced from low to high to form a sequence X1The capacitors C in the N sub-modules2The voltage signals of (1) are ordered from high to low to form a sequence X2. If N is presentpa>NdPositive input sequence X1Middle front Npa-NdA capacitor; if N is presentpa<NdTime, negative input sequence X2Middle front Nd-NpaA capacitor.
When bridge arm current ism<When 0, 2N measured capacitance voltage signals are sequenced from high to low to form a sequence X3The capacitors C in the N sub-modules2The voltage signals of (A) are ordered from low to high to form a sequence X4. If N is presentpa>NdPositive input sequence X3Middle front Npa-NdA capacitor; if N is presentpa<NdTime, negative input sequence X4Middle front Nd-NpaA capacitor.
In order to better illustrate the performance of the DCHSM, a 21-level single-ended MMC-HVDC system is built by Matlab/simulink, and the normal working state and the locking state of the DCHSM are simulated. A double short fault occurs at 0.8s, and all sub-modules latch up at 0.802 s.
As can be seen from fig. 5(a), a 21-level step wave is generated on the ac side in normal operation. A bipolar short-circuit fault occurs at 0.8s, the dc side current rises rapidly, all sub-modules latch up at 0.802s, and the dc side current drops to 0 in about 6ms, as shown in fig. 5 (b). Simulation results prove that the DCHSM can realize reliable commutation in normal work and has fault current clearing capability after locking.
After DCHSM is locked, the capacitor C1And C2In parallel state, fault current is applied to capacitor C1And C2The charging effect of (a) is approximately the same. As shown in fig. 5(c), the self-voltage-sharing effect of the capacitors on the bridge arms is good after the fault current is cleared, which is beneficial to the quick restart of the system.
The voltage drop of the direct current side is 20% when the voltage is set to be 3.8s, the system detects the voltage drop when the voltage is 3.802s, and the normal operation state is converted into a non-locking low-voltage fault ride-through state. The voltage on the direct current side is recovered at 6s, and the system is converted into a normal operation state from a non-latching low-voltage fault ride-through state at 6.002 s. The simulation results are shown in fig. 6:
as shown in fig. 6(a) and 6(b), the dc current rapidly increases after a slight drop in the dc bus voltage. After the system is switched to a low-voltage fault ride-through state to operate, the output voltage of the direct-current side of the MMC converter is reduced to about 16kV along with the voltage of the direct-current bus, and the direct current is rapidly reduced and reaches a new stable value. And after the voltage of the direct current bus is recovered, the direct current side current is recovered to a normal operation state. As shown in fig. 6(c), during low voltage operation, the ac side voltage remains stable and the system can still maintain power transfer.
The present invention is not limited to the above embodiments, and any changes or substitutions that can be easily made by those skilled in the art within the technical scope of the present invention are also within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (3)

1. A diode-clamped hybrid sub-module (DCHSM) of an MMC, the DCHSM comprising a half-bridge-full-bridge hybrid sub-module (HB-FBSM) and a clamp diode; the cathode of the clamping diode is connected with the anode of the capacitor of the half-bridge submodule of the HB-FBSM, and the anode of the clamping diode is connected with the anode of the capacitor of the full-bridge submodule of the HB-FBSM.
2. The diode-clamped hybrid submodule (DCHSM) of an MMC according to claim 1, wherein: after the DCHSM is locked, the clamping diode introduces fault current into the capacitor of the half-bridge sub-module of the HB-FBSM, the fault current charges the capacitor of the half-bridge sub-module of the HB-FBSM and the capacitor of the full-bridge sub-module of the HB-FBSM in parallel, and the voltage of the internal capacitor of the DCHSM is kept balanced during locking.
3. A latch-up free low voltage fault ride-through method for MMC applying a diode-clamped hybrid sub-module (DCHSM) of an MMC according to any of claims 1-2, characterized in that, when a slight drop in the MMC dc-side voltage occurs, for a certain phase:
when the DCHSM bridge arm current ism>When 0, 2N measured capacitance voltage signals are sequenced from low to high to form a sequence X1Sequencing voltage signals of capacitors of a full-bridge submodule of HB-FBSM from N DCHSM submodules from high to low to form a sequence X2If the number of capacitors N is put into the bridge arm in the normal statep>Nd，NdPositive input sequence X1Middle front Np-NdA capacitor; if N is presentp<NdTime, negative input sequence X2Middle front Nd-NpA capacitor, NdThe number of the levels required to be reduced for the upper bridge arm and the lower bridge arm;
when bridge arm current ism<When 0, 2N measured capacitance voltage signals are sequenced from high to low to form a sequence X3Sequencing voltage signals of capacitors of HB-FBSM full-bridge submodule in N DCHSM submodules from low to high to form a sequence X4If the number of capacitors N is put into the bridge arm in the normal statep>NdPositive input sequence X3Middle front Np-NdA capacitor; if N is presentp<NdTime, negative input sequence X4Middle front Nd-NpA capacitor.
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CN112688547A (en) * 2020-12-22 2021-04-20 许继集团有限公司 Fault-tolerant control method and device for asymmetric operation fault of MMC-HCDC bridge arm
CN112865506A (en) * 2021-03-17 2021-05-28 西安交通大学 MMC dual-sub-module with bidirectional fault current removal capability
CN113472229A (en) * 2021-07-15 2021-10-01 昆明理工大学 Hybrid bridge arm topological structure with direct-current fault clearing and voltage-sharing capabilities
CN116722760A (en) * 2023-08-10 2023-09-08 华北电力大学（保定） Bridge arm topological structure for blocking-free fault ride through and control method thereof
CN116760272A (en) * 2023-08-11 2023-09-15 西安西电电力系统有限公司 Method and device for inhibiting voltage of submodule of modularized multi-level converter
CN117134583A (en) * 2023-08-31 2023-11-28 山东理工大学 Unidirectional power hybrid MMC control method

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5579197A (en) * 1995-01-24 1996-11-26 Best Power Technology, Incorporated Backup power system and method
CN104362616A (en) * 2014-10-20 2015-02-18 许继电气股份有限公司 Direct-current short-circuit fault ride-through method of modular multilevel converter of full-bridge submodule
CN106787087A (en) * 2017-01-09 2017-05-31 许继集团有限公司 Hybrid MMC sequences pressure charging method, startup method and device
CN106849718A (en) * 2017-02-17 2017-06-13 许继集团有限公司 One seed module is topological and a kind of MMC transverters
CN107196325A (en) * 2017-04-10 2017-09-22 华北电力大学 It is a kind of by mixed-voltage source type current conversion station constitute without dc-couple type direct current network topology
CN107231085A (en) * 2017-04-07 2017-10-03 中国矿业大学 One kind is based on the bipolar equipotential MMC HVDC direct-current short circuit fault ride-through methods of dc bus
US9893633B1 (en) * 2016-03-23 2018-02-13 The Florida State University Research Foundation, Inc. Modular multilevel DC-DC converter and associated method of use
CN109728594A (en) * 2018-12-19 2019-05-07 华北电力大学 A kind of DC Line Fault traversing control method of hybrid converter station
CN110535359A (en) * 2019-08-29 2019-12-03 华北电力大学（保定） A kind of diode clamp mixing MMC circuit with from equal pressure energy power

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5579197A (en) * 1995-01-24 1996-11-26 Best Power Technology, Incorporated Backup power system and method
CN104362616A (en) * 2014-10-20 2015-02-18 许继电气股份有限公司 Direct-current short-circuit fault ride-through method of modular multilevel converter of full-bridge submodule
US9893633B1 (en) * 2016-03-23 2018-02-13 The Florida State University Research Foundation, Inc. Modular multilevel DC-DC converter and associated method of use
CN106787087A (en) * 2017-01-09 2017-05-31 许继集团有限公司 Hybrid MMC sequences pressure charging method, startup method and device
CN106849718A (en) * 2017-02-17 2017-06-13 许继集团有限公司 One seed module is topological and a kind of MMC transverters
CN107231085A (en) * 2017-04-07 2017-10-03 中国矿业大学 One kind is based on the bipolar equipotential MMC HVDC direct-current short circuit fault ride-through methods of dc bus
CN107196325A (en) * 2017-04-10 2017-09-22 华北电力大学 It is a kind of by mixed-voltage source type current conversion station constitute without dc-couple type direct current network topology
CN109728594A (en) * 2018-12-19 2019-05-07 华北电力大学 A kind of DC Line Fault traversing control method of hybrid converter station
CN110535359A (en) * 2019-08-29 2019-12-03 华北电力大学（保定） A kind of diode clamp mixing MMC circuit with from equal pressure energy power

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
向往: "适用于架空线路传输的MMC拓扑结构及关键技术研究", 《中国博士学位论文全文数据库 工程科技Ⅱ辑》, no. 10, pages 4 - 3 *
胡灿: "直流配电网中MMC的控制技术研究", 《中国优秀硕士学位论文全文数据库 工程科技Ⅱ辑》, no. 01, pages 2 - 4 *

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112688547A (en) * 2020-12-22 2021-04-20 许继集团有限公司 Fault-tolerant control method and device for asymmetric operation fault of MMC-HCDC bridge arm
CN112688547B (en) * 2020-12-22 2022-05-20 许继集团有限公司 Fault-tolerant control method and device for asymmetric operation fault of MMC-HVDC bridge arm
CN112865506A (en) * 2021-03-17 2021-05-28 西安交通大学 MMC dual-sub-module with bidirectional fault current removal capability
CN113472229A (en) * 2021-07-15 2021-10-01 昆明理工大学 Hybrid bridge arm topological structure with direct-current fault clearing and voltage-sharing capabilities
CN113472229B (en) * 2021-07-15 2024-04-26 昆明理工大学 Hybrid bridge arm topological structure with direct current fault clearing and voltage equalizing capabilities
CN116722760A (en) * 2023-08-10 2023-09-08 华北电力大学（保定） Bridge arm topological structure for blocking-free fault ride through and control method thereof
CN116722760B (en) * 2023-08-10 2023-10-24 华北电力大学（保定） Bridge arm topological structure for blocking-free fault ride through and control method thereof
CN116760272A (en) * 2023-08-11 2023-09-15 西安西电电力系统有限公司 Method and device for inhibiting voltage of submodule of modularized multi-level converter
CN116760272B (en) * 2023-08-11 2023-12-01 西安西电电力系统有限公司 Method and device for inhibiting voltage of submodule of modularized multi-level converter
CN117134583A (en) * 2023-08-31 2023-11-28 山东理工大学 Unidirectional power hybrid MMC control method
CN117134583B (en) * 2023-08-31 2024-03-26 山东理工大学 Unidirectional power hybrid MMC control method

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