CN107196539B - A kind of MMC zero DC voltage fault traversing control method under bridge arm parameter unbalance state - Google Patents

A kind of MMC zero DC voltage fault traversing control method under bridge arm parameter unbalance state Download PDF

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Publication number
CN107196539B
CN107196539B CN201710488320.XA CN201710488320A CN107196539B CN 107196539 B CN107196539 B CN 107196539B CN 201710488320 A CN201710488320 A CN 201710488320A CN 107196539 B CN107196539 B CN 107196539B
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bridge arm
phase
anode
voltage
submodule
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CN107196539A (en
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王跃
段国朝
尹太元
尹诗媛
周晖
王璋
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Xian Jiaotong University
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Xian Jiaotong 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
    • 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
    • H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
    • 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
    • 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
    • H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
    • 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
    • H02M1/322—Means for rapidly discharging a capacitor of the converter for protecting electrical components or for preventing electrical shock
    • 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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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention discloses the zero DC voltage fault traversing control method of MMC under a kind of bridge arm parameter unbalance state, MMC Neutron module all uses full-bridge submodule, and adds subsidiary loop between the bridge arm of same DC bus side and construct new topology；During zero DC voltage fault traversing, auxiliary circuit work keeps the balancing energy of three upper bridge arms and the balancing energy of three lower bridge arms between bridge arm；Keep all module voltages whole balanced by the adjusting of upper and lower bridge arm voltage deviation again, guarantee to remove fault current during zero DC voltage fault traversing of MMC, continue to provide reactive power support to AC system, maintain submodule balancing energy, especially in MMC bridge arm parameter unbalance, the topology and its control method are still able to achieve voltage deviation caused by 6 bridge arm shared bridge arm parameter unbalances, maintain energy whole balanced, short circuit current is restricted to very low level, realizes zero DC voltage fault traversing.

Description

A kind of zero DC voltage fault traversing of MMC control under bridge arm parameter unbalance state Method
Technical field
The invention belongs to flexible DC transmission technology fields, and in particular to the MMC under a kind of bridge arm parameter unbalance state Zero DC voltage fault traversing control method.
Background technique
Flexible DC transmission technology (voltage sourced converter based high voltage direct Current, VSC-HVDC) it is building one of energy internet and the key technology of DC distribution net, the modular multilevel change of current Device (modular multilevel converter, MMC) is by no static state voltage equipoise, high efficiency, the advantages such as low EMI at For the prevailing topology of flexible direct current transmission converter station, in VSC-HVDC technology development process, direct-current short circuit fault traversing is One of major issue faced at present.Although traditional MMC topology has the advantage of low-cost high-efficiency using half-bridge submodule, But does not have DC Line Fault ride-through capability, need AC circuit breaker protection after DC Line Fault occurs.In order to make MMC have failure Ride-through capability, researcher successively propose full-bridge submodule clamp Shuangzi module, series connection Shuangzi module, enhance from resistance type submodule Block etc. is able to achieve the submodule topology of fault current blocking, and the MMC constituted using such submodule will when DC Line Fault occurs Submodule locking, submodule capacitor provide counter electromotive force and block alternating current path, realize MMC DC Line Fault self-cleaning.
It since full-bridge submodule can be worked normally in the case where exporting generating positive and negative voltage, is widely used, is constituted with full-bridge submodule MMC (hereinafter referred to as bridge-type MMC) have more advantages continue as exchanging if not being latched converter valve during DC Line Fault System provides reactive power support, realizes zero DC voltage fault traversing；Negative voltage goes to dissociate after Failure elimination, acceleration disturbance point insulating Restore etc..Although bridge-type MMC has many advantages as above during zero DC voltage fault traversing, due to DC side electricity Pressure is zero, and upper and lower bridge arm submodule electric voltage equalization is difficult.Capacitor electricity during the zero DC voltage fault traversing proposed at present Pressing balance control method includes that circulation injection method and upper and lower bridge arm independent control method can guarantee son when bridge arm parameter is symmetrical Module capacitance electric voltage equalization removes direct fault current；But when bridge arm parameter unbalance, during fault traversing up and down Bridge arm module balancing energy is difficult, and DC side output voltage is caused to be not zero, i.e., can generate biggish short circuit current in short dot, It is full symmetric to can not achieve bridge arm parameter in Practical Project.
Summary of the invention
When for bridge-type MMC bridge arm parameter unbalance, upper and lower bridge arm submodule during zero DC voltage fault traversing The problem of block presses difficulty, and DC side output voltage is not zero, the invention proposes under a kind of bridge arm parameter unbalance state Zero DC voltage fault traversing control method of MMC guarantees that MMC removes fault current during zero DC voltage fault traversing, Continue to provide reactive power support to AC system, maintains submodule balancing energy.
The present invention adopts the following technical scheme:
A kind of zero DC voltage fault traversing control method of MMC under bridge arm parameter unbalance state, the MMC is by full-bridge It assists pushing back road composition between the MMC model and bridge arm of module composition, which includes the following steps:
1) under bridge arm parameter unbalance state zero DC voltage fault traversing of MMC control using dq coordinate system voltage and Current double closed-loop control strategy obtains the practical three-phase output electric current and network voltage of inverter through over-sampling, is sat Mark transformation obtains the dq component i of output electric currentdAnd iq, the dq component of network voltage is usdAnd usq, and lock electric using phaselocked loop Net voltage-phase ω t；
2) outer loop voltag control, the voltage for acquiring all modules are averaged Uave_all, and with submodule capacitor voltage volume Determine UcValue is made comparisons, and is compared difference and is obtained watt current control instruction after proportional integration link
3) open sea wharf, idle reference instruction QrefDivided by the d axis component u of network voltagesdObtain reactive current reference Instruction
4) inner ring current feed-forward decoupling control, the watt current reference instruction that outer ring obtainsWith reactive current reference instructionU is generated after current feed-forward decoupling control linkd,uq, and acquire ud,uqThe amplitude U of resultant voltagemAnd phase angle
5) bridge arm voltage bias adjustment controls, and it is electric to its capacitor to choose three bridge arms of every phase not in same DC bus side Pressure is adjusted, bridge arm average voltage Uave_armRespectively with submodule capacitor voltage rated value UcIt makes comparisons, difference is through proportional integration After device, the phase angle adjustment amount of three-phase lower bridge arm reference instruction is generatedJ=a, b, c；
6) the phase angle adjustment amount that step 5) obtainsThe rapid voltage-phase ω t 1) obtained is added respectively, what step 4) obtained Phase angleAdd the phase difference of three-phase respectively againThe phase angle of inverter three-phase lower bridge arm modulation waveform is obtained afterwards
7) the three-phase lower bridge arm modulating wave phase angle that step 6) obtainsIt takes sine value and believes multiplied by the modulation that step 4) obtains Number amplitude UmThe modulated signal u of circulator three-phase lower bridge arm is obtained afterwardsad_ref,ubd_ref,ucd_ref, changed after negating respectively Flow the modulated signal u of bridge arm on device three-phaseau_ref,ubu_ref,ucu_ref, modulated signal using nearest level approach modulation and The trigger signal of inverter submodule is obtained after pressure sequence algorithm, and then for triggering corresponding submodule.
A further improvement of the present invention lies in that six bridge arm structure of three-phase that MMC topology is made of bridge-type submodule.
A further improvement of the present invention lies in that assist pushing back between bridge arm road be arranged on three-phase bridge arm first it is complete Between bridge submodule between three-phase lower bridge arm n-th full-bridge submodule, the auxiliary between two neighboring module pushes back routing Three diodes, an auxiliary capacitor and an IGBT composition；Bridge arm first sub- module capacitance C in A phaseAu_1Anode through two Pole pipe connects auxiliary capacitor C1Anode, capacitor C1Cathode be connected in direct current positive bus through diode, in addition, auxiliary capacitor C1 Anode through assist IGBT T1It is connected to the 1st module capacitance C of bridge arm in B phaseBu_1Anode, capacitor CBu_1Cathode through two poles Pipe is connected to bridge arm auxiliary capacitor C in A phase1Cathode, constitute alternate circuit, and so on, bridge arm auxiliary capacitor C in B phase2's Anode is through assisting IGBT T2It is connected to the 1st module capacitance C of bridge arm in C phaseCu_1Anode, CCu_1Cathode be connected in B phase Bridge arm auxiliary capacitor C2Cathode, likewise, bridge arm auxiliary capacitor C in C phase3It is connected to first sub- module capacitance of bridge arm in A phase CAu_1On, first module composition triangle circuit of bridge arm on three-phase；It is similar with upper bridge arm, the alternate auxiliary of lower bridge arm is returned Road, A phase lower bridge arm n-th module capacitance CAd_nAnode through booster diode be connected to lower bridge arm auxiliary capacitor C4Anode, auxiliary Capacitor C4Cathode be directly connected in direct current negative busbar, C4Anode through assist IGBT T4Be connected to B phase lower bridge arm last A sub- module capacitance CBd_nAnode, auxiliary capacitor C4With the last one submodule capacitor of B phase CBd_nCathode pass through the negative mother of direct current Line is connected, likewise, the last one submodule capacitor of B phase lower bridge arm CBd_nAnode through diode connect auxiliary capacitor C5Just Pole, auxiliary capacitor C5Cathode meet direct current negative busbar, auxiliary capacitor C5Anode through assist IGBT T5It is last to be connected to C phase lower bridge arm One sub- module capacitance CCd_nAnode, CCd_nCathode through direct current negative busbar constitute circuit, the last one submodule of C phase lower bridge arm Block capacitor CCd_nAnode through diode connect auxiliary capacitor C6Anode, auxiliary capacitor C6Cathode connect direct current negative busbar, auxiliary electricity Hold C6Anode through assist IGBT T6It is connected to the last one submodule capacitor of A phase lower bridge arm CAd_nAnode, CAd_nCathode warp Direct current negative busbar constitutes circuit；In this way, the last one submodule of three-phase lower bridge arm constitutes triangle by alternate auxiliary circuit Circuit, the mutual equilibrium between mutual balanced and lower bridge arm in realization between bridge arm.
A further improvement of the present invention lies in that the upper bridge arm number of A, B, C three-phase is respectively 1,3,5, lower bridge arm number is 4,6,2, three bridge arms not in same DC bus side are chosen in bridge arm voltage bias adjustment link, and its capacitance voltage is carried out It adjusts, totally 1,2,3,2,3,4,3,4,5,4,5,6,5,6,1,6, any one combination is chosen in 1,2 six kind of combination, will corresponding bridge Arm energy adjusting is to specified.
A further improvement of the present invention lies in that low pressure molding when submodule capacitor switching follows bridge arm module charging inside bridge arm Block preferentially charges, when submodule discharges, the principle switching of high-pressure modular preferential discharge.
Compared with prior art, the present invention has the advantage that:
Zero DC voltage fault traversing control method of MMC under a kind of bridge arm parameter unbalance state provided by the invention In, it is not latched converter valve during bridge-type MMC DC Line Fault, is remained running under STATCOM mode, for the friendship of converter station connection Streaming system provides reactive power support, when dc-side short-circuit fault occurs using the negative pressure output characteristics of full-bridge modules, by DC side Voltage control is zero, and short circuit current is reduced to zero, realizes zero DC voltage fault traversing.
Further, assisting pushing back road between converter bridge arm reaches the energy between the bridge arm of same DC bus side three Equilibrium pushes back road by alternate auxiliary between first submodule of bridge arm on three-phase and constitutes triangular structure, after stable operation Energy energy automatic equalization similarly assists pushing back road composition triangular structure between three-phase lower bridge arm also by alternate, therefore under Energy energy also can automatic equalization between bridge arm.
Further, the method being uniformly controlled using upper and lower bridge arm only passes through deviation tune to the energy of single bridge arm in every phase Section, which is adjusted, arrives rated value, guarantees the big reverse phase such as upper and lower bridge arm modulation waveform moment, guarantee upper and lower bridge arm output voltage and always It is zero.
Further, bridge arm internal module capacitance voltage reaches consistent by the pressure strategy that sorts；It is auxiliary between bridge arm bridge arm on three-phase It helps and pushes back road and make to reach between bridge arm balanced, the voltage that the auxiliary between lower bridge arm pushes back between road maintenance lower bridge arm is equal Weighing apparatus using not establishing connection by the way of the bridge arm bias adjustment of same DC bus side three between upper and lower bridge arm, therefore works as bridge When arm parameter unbalance, the energy deviation of generation has all module shareds, and all module voltages reach whole equilibrium, Short circuit current can be restricted to very low level during zero DC voltage fault traversing.
Further, hardware-assist circuit only works in failure difference crossing process, will not introduce excessive operating cost, and Hardware-assist circuit merely adds 6 IGBT, 6 capacitors and 18 diodes, and high-voltage large-capacity flexible DC transmission is changed In stream station for hundreds and thousands of a modules, the cost of investment that auxiliary circuit introduces is also very limited.
Detailed description of the invention
Fig. 1 is the schematic diagram of bridge-type submodule；
Fig. 2 is the MMC topology schematic diagram for having zero DC voltage fault ride-through capacity；
Fig. 3 assists pushing back road operation schematic diagram between the bridge arm of same DC bus side three；
System equivalent model during Fig. 4 is zero DC voltage fault traversing；
Fig. 5 is system entirety control block diagram；
When Fig. 6 is bridge arm parameter unbalance under the bipolar short trouble of DC side, the submodule that conventional method controls is electric Corrugating；
When Fig. 7 is bridge arm parameter unbalance under the bipolar short trouble of DC side, the submodule that inventive method controls is electric Corrugating；
When Fig. 8 is bridge arm parameter unbalance under the bipolar short trouble of DC side, the short dot that conventional method controls is electric Current voltage waveform；
When Fig. 9 is bridge arm parameter unbalance under the bipolar short trouble of DC side, the short dot that inventive method controls is electric Current voltage waveform.
Specific embodiment
Topology and working principle of the invention are described in further detail below with reference to specific embodiment, it is described to be Explanation of the invention rather than limit.
With reference to Fig. 1, for the zero DC voltage fault traversing controlling party of MMC under a kind of bridge arm parameter unbalance state of the present invention Full-bridge submodule used in the topology of method control.
Zero DC voltage fault traversing control method of MMC with reference to Fig. 2, under a kind of bridge arm parameter unbalance state of the present invention The topology of control is by tri- phase composition of A, B, C, and every phase is made of upper and lower two bridge arms, a total of N number of full-bridge submodule on each bridge arm Block, full-bridge submodule block number is followed successively by 1~N from top to bottom on each bridge arm.
It is arranged on three-phase between first full-bridge submodule of bridge arm and three with reference to assisting pushing back road between Fig. 2 bridge arm Between n-th of full-bridge submodule of phase lower bridge arm, the auxiliary between two neighboring module pushes back three diodes of routing, and one auxiliary Help capacitor and an IGBT composition；Bridge arm first sub- module capacitance C in A phaseAu1Anode through diode connect auxiliary capacitor C1 Anode, capacitor C1Cathode be connected in direct current positive bus through diode, in addition, auxiliary capacitor C1Anode through assist IGBT T1 It is connected to the 1st module capacitance C of bridge arm in B phaseBu1Anode, capacitor CBu1Cathode through diode to be connected to bridge arm in A phase auxiliary Help capacitor C1Cathode, constitute alternate circuit, and so on, bridge arm auxiliary capacitor C in B phase2Anode through assist IGBT T2Even It is connected to the 1st module capacitance C of bridge arm in C phaseCu1Anode, CCu1Cathode be connected to bridge arm auxiliary capacitor C in B phase2Cathode, Likewise, bridge arm auxiliary capacitor C in C phase3It is connected to bridge arm first sub- module capacitance C in A phaseAu1On, bridge arm first on three-phase A module composition triangle circuit；It is similar with upper bridge arm, for the alternate subsidiary loop of lower bridge arm, A phase lower bridge arm n-th module Capacitor CAdnAnode through booster diode be connected to lower bridge arm auxiliary capacitor C4Anode, auxiliary capacitor C4Cathode be directly connected to In direct current negative busbar, C4Anode through assist IGBT T4It is connected to the last one submodule capacitor of B phase lower bridge arm CBdnAnode, Auxiliary capacitor C4With the last one submodule capacitor of B phase CBdnCathode be connected by direct current negative busbar, likewise, bridge under B phase The last one submodule capacitor of arm CBdnAnode through diode connect auxiliary capacitor C5Anode, auxiliary capacitor C5Cathode connect direct current Negative busbar, auxiliary capacitor C5Anode through assist IGBT T5It is connected to the last one submodule capacitor of C phase lower bridge arm CCdnAnode, CCdnCathode through direct current negative busbar constitute circuit, the last one submodule capacitor of C phase lower bridge arm CCdnAnode connect through diode Meet auxiliary capacitor C6Anode, auxiliary capacitor C6Cathode meet direct current negative busbar, auxiliary capacitor C6Anode through assist IGBT T6It connects To the last one submodule capacitor of A phase lower bridge arm CAdnAnode, CAdnCathode through direct current negative busbar constitute circuit；In this way, three The last one submodule of phase lower bridge arm also passes through alternate auxiliary circuit and constitutes triangle circuit, mutual between bridge arm in realization Mutual equilibrium between balanced and lower bridge arm.
With reference to Fig. 3 with A, for the subsidiary loop in B phase between first submodule of bridge arm, C1,C2Respectively A, B phase Auxiliary capacitor, T1For alternate subsidiary loop switch, D1Clamp diode in road is pushed back for alternate auxiliary, when bridge arm the in A phase The IGBT T of one submodule0When conducting, at this time if first module capacitance C of bridge arm in A phaseAu1Voltage be higher than auxiliary electricity Hold C1Voltage when, module capacitance CAu1Auxiliary capacitor C can be given1Charging, because diode clamp acts on, when stable operation, meets Uc1 ≥UcAu1；When first module is in excision state, auxiliary IGBT T is allowed1Conducting, at this time if auxiliary capacitor C1On voltage it is high In first module capacitance C of bridge arm in B phaseBu1Voltage, auxiliary capacitor will be to module capacitance CBu1Electric discharge.
With reference to structure class after a kind of MMC DC side generation short trouble for having zero DC voltage fault ride-through capacity of Fig. 4 It is similar to two star-like STATCOM of chain type to be in parallel, as full-bridge submodule constitutes star-like 1 He of STATCOM in bridge arm on three-phase in figure The star-like STATCOM 2 that full-bridge submodule is constituted in three-phase lower bridge arm is connected in parallel on exchange system by respective bridge arm reactor simultaneously On system, but compared with general two star-like STATCOM parallel-connection structures, equivalent two after MMC direct current generation short trouble The neutral point of STATCOM is connected by MMC dc-side short-circuit point.
With reference to the zero DC voltage fault traversing control method of MMC under a kind of bridge arm parameter unbalance state of Fig. 5 include with Lower step:
1) under bridge arm parameter unbalance state zero DC voltage fault traversing of MMC control using dq coordinate system voltage and Current double closed-loop control strategy obtains the practical three-phase output electric current and network voltage of inverter through over-sampling, is sat Mark transformation obtains the dq component i of output electric currentdAnd iq, the dq component of network voltage is usdAnd usq, and lock electric using phaselocked loop Net voltage-phase ω t；
2) outer loop voltag control, the voltage for acquiring all modules are averaged Uave_all, and with submodule capacitor voltage volume Determine UcValue is made comparisons, and is compared difference and is obtained watt current control instruction after proportional integration link
3) open sea wharf, idle reference instruction QrefDivided by the d axis component u of network voltagesdObtain reactive current reference Instruction
4) inner ring current feed-forward decoupling control, the watt current reference instruction that outer ring obtainsWith reactive current reference instructionU is generated after current feed-forward decoupling control linkd,uq, and acquire ud,uqThe amplitude U of resultant voltagemAnd phase angle
5) bridge arm voltage bias adjustment controls, and it is electric to its capacitor to choose three bridge arms of every phase not in same DC bus side Pressure is adjusted, bridge arm average voltage Uave_armRespectively with submodule capacitor voltage rated value UcIt makes comparisons, difference is through proportional integration After device, the phase angle adjustment amount of three-phase lower bridge arm reference instruction is generatedJ=a, b, c；
6) the phase angle adjustment amount that step 5) obtainsThe rapid voltage-phase ω t 1) obtained is added respectively, what step 4) obtained Phase angleAdd the phase difference of three-phase respectively againThe phase angle of inverter three-phase lower bridge arm modulation waveform is obtained afterwards
7) the three-phase lower bridge arm modulating wave phase angle that step 6) obtainsIt takes sine value and believes multiplied by the modulation that step 4) obtains Number amplitude UmThe modulated signal u of circulator three-phase lower bridge arm is obtained afterwardsad_ref,ubd_ref,ucd_ref, changed after negating respectively Flow the modulated signal u of bridge arm on device three-phaseau_ref,ubu_ref,ucu_ref, modulated signal using nearest level approach modulation and The trigger signal of inverter submodule is obtained after pressure sequence algorithm, and then for triggering corresponding submodule.
Embodiment
Description according to the present invention, in examples of simulation using the capacitance voltage of three-phase symmetrical from balanced topology as shown in Figure 1, It, which is exchanged, flanks 380V AC network voltage rating, and DC side voltage rating is 700V；Using 11 level blocks, i.e., above and below every phase Bridge arm respectively has 10 sub- full-bridge modules to constitute, and submodule capacitor is 3300 μ F, and submodule capacitor voltage rating is 70V；Bridge arm electricity Anti- device is 20mH；When bridge arm parameter is full symmetric, traditional control method and the mentioned method of the present invention can realize balancing energy.If It sets the loss of A phase lower bridge arm and increases 10W, i.e. A phase upper and lower bridge arm parameter unbalance, matlab/Simulink simulation result is as follows, is It unites after stable operation, with reference to Fig. 6, when using traditional control method, the loss of A phase lower bridge arm increases 10W, and bias adjustment is acted on to it More active maintenance balancing energies are injected, bridge arm is infused since A phase active power is injected in A phase at this time, and module voltage rises, partially From rated value 70V, reach 74V, fluctuate more than 5%, B, C phase are consistent due to being lost, and upper and lower bridge arm module capacitance voltage is consistent；It adopts After the control method in the present invention, with reference to Fig. 7, energy caused by A phase lower bridge arm parameter unbalance is unbalanced by all bridge arms Shared, although deviation all occurs in every phase upper and lower bridge arm, deviation voltage is no more than 2%, i.e., 2.8%, all modules Reach whole equilibrium；With reference to Fig. 8, since A phase fluctuating plate is more excessive than deviation under traditional control method, dc-side short-circuit point electric current compared with Greatly, amplitude reaches 2.5A, and after control control method of the invention, current in the short amplitude drops to 0.4A, is original 1/6, therefore for the bridge-type MMC converter station of high-power during zero DC voltage fault traversing, the present invention proposes Control method can significantly reduce dc-side short-circuit electric current.

Claims (5)

1. the zero DC voltage fault traversing control method of MMC under a kind of bridge arm parameter unbalance state, which is characterized in that should Auxiliary between bridge arm and bridge arm that MMC inverter is made of full-bridge submodule and inductance connection pushes back road and constitutes, the control Method includes the following steps:
1) zero DC voltage fault traversing of the MMC inverter control under bridge arm parameter unbalance state uses the voltage of dq coordinate system With current double closed-loop control strategy, obtain the practical three-phase output electric current and network voltage of MMC inverter through over-sampling, by its into Row coordinate transform obtains the dq component i of output electric currentdAnd iq, the dq component of network voltage is usdAnd usq, and locked using phaselocked loop Obtain electric network voltage phase ω t；
2) outer loop voltag control, the voltage for acquiring all submodules are averaged Uave_all, and with submodule capacitor voltage rated value UcIt makes comparisons, compares difference and obtain watt current control instruction after proportional integration link
3) open sea wharf, idle reference instruction QrefDivided by the d axis component u of network voltagesdObtain reactive current reference instruction
4) inner ring current feed-forward decoupling control, the watt current reference instruction that outer ring obtainsWith reactive current reference instructionThrough U is generated after current feed-forward decoupling control linkd,uq, and acquire ud,uqThe amplitude U of resultant voltagemAnd phase angle
5) bridge arm voltage bias adjustment control, choose every phase not same DC bus side three bridge arms to its capacitance voltage into Row adjustment, in three selected bridge arms the respective submodule average voltage of each bridge arm respectively with submodule capacitor voltage volume Definite value UcIt makes comparisons, gained difference is first multiplied by reactive current reference instructionBy the later value of sign function sign (x), then After being adjusted by proportional integrator, the phase angle adjustment amount of three-phase lower bridge arm reference instruction is generated
6) the phase angle adjustment amount that step 5) obtainsThe electric network voltage phase ω t obtained respectively plus step 1), step 4) The phase angle arrivedAdd the phase difference of three-phase respectively againAfter obtain MMC inverter three-phase lower bridge arm modulation waveform Phase angle
7) the three-phase lower bridge arm modulating wave phase angle that step 6) obtainsThe modulated signal width for taking sine value and being obtained multiplied by step 4) Value UmThe modulated signal u of MMC inverter three-phase lower bridge arm is obtained afterwardsad_ref,ubd_ref,ucd_ref, MMC is obtained after negating respectively The modulated signal u of bridge arm on inverter three-phaseau_ref,ubu_ref,ucu_ref, modulated signal using nearest level approach modulation and The trigger signal of MMC inverter submodule is obtained after equal pressure sequence algorithm, and then for triggering corresponding submodule.
2. the zero DC voltage fault traversing of MMC under a kind of bridge arm parameter unbalance state according to claim 1 controls Method, which is characterized in that MMC topology includes six bridge arm structure of three-phase being made of bridge-type submodule.
3. the zero DC voltage fault traversing controlling party of MMC under a kind of bridge arm parameter unbalance state according to claim 1 Method, which is characterized in that assist pushing back road between bridge arm and be arranged on three-phase between first full-bridge submodule of bridge arm and three Between phase lower bridge arm n-th full-bridge submodule, the auxiliary between two neighboring module, which pushes back, routes three booster diodes, and one A auxiliary capacitor and an IGBT composition；Bridge arm first sub- module capacitance C in A phaseAu_1Anode connected through booster diode Auxiliary capacitor C1Anode, auxiliary capacitor C1Cathode be connected in direct current positive bus through booster diode, in addition, auxiliary capacitor C1 Anode through assist IGBT T1It is connected to the 1st sub- module capacitance C of bridge arm in B phaseBu_1Anode, capacitor CBu_1Cathode through auxiliary Diode is helped to be connected to bridge arm auxiliary capacitor C in A phase1Cathode, constitute alternate circuit, and so on, bridge arm first in B phase Submodule capacitor CBu_1Anode through booster diode connect auxiliary capacitor C2Anode, bridge arm auxiliary capacitor C in B phase2Anode warp Assist IGBT T2It is connected to the 1st sub- module capacitance C of bridge arm in C phaseCu_1Anode, CCu_1Cathode connected through booster diode Bridge arm auxiliary capacitor C on to B phase2Cathode, auxiliary capacitor C2Cathode be connected in direct current positive bus through booster diode, together Sample, bridge arm first sub- module capacitance C in C phaseCu_1Anode through booster diode connect auxiliary capacitor C3Anode, in C phase Bridge arm auxiliary capacitor C3Anode by auxiliary IGBT T3It is connected to bridge arm first sub- module capacitance C in A phaseAu_1Anode On, auxiliary capacitor C3Cathode pass through booster diode connect direct current positive bus, capacitor CAu_1Cathode connected through booster diode Bridge arm auxiliary capacitor C on to C phase3Cathode, first module composition triangle circuit of bridge arm on three-phase；It is similar with upper bridge arm, For the alternate subsidiary loop of lower bridge arm, A phase lower bridge arm n-th module capacitance CAd_nAnode through booster diode be connected to lower bridge Arm auxiliary capacitor C4Anode, auxiliary capacitor C4Cathode be connected in direct current negative busbar by booster diode, auxiliary capacitor C4 Anode through assist IGBT T4It is connected to the last one submodule capacitor of B phase lower bridge arm CBd_nAnode, auxiliary capacitor C4It is negative Pole and the last one submodule capacitor of B phase CBd_nCathode be connected by booster diode, likewise, B phase lower bridge arm is last One sub- module capacitance CBd_nAnode through booster diode connect auxiliary capacitor C5Anode, auxiliary capacitor C5Cathode by auxiliary Diode is helped to connect direct current negative busbar, auxiliary capacitor C5Anode through assist IGBT T5It is connected to the last one submodule of C phase lower bridge arm Block capacitor CCd_nAnode, CCd_nCathode through booster diode connect auxiliary capacitor C5Cathode constitute circuit, C phase lower bridge arm The last one submodule capacitor CCd_nAnode through booster diode connect auxiliary capacitor C6Anode, auxiliary capacitor C6Cathode warp Booster diode meets direct current negative busbar, auxiliary capacitor C6Anode through assist IGBT T6It is connected to the last one submodule of A phase lower bridge arm Block capacitor CAd_nAnode, CAd_nCathode through booster diode connect auxiliary capacitor C6Cathode constitute circuit；In this way, three-phase The last one submodule of lower bridge arm constitutes triangle circuit by alternate auxiliary circuit, the mutual equilibrium in realization between bridge arm Mutual equilibrium between lower bridge arm.
4. the zero DC voltage fault traversing controlling party of MMC under a kind of bridge arm parameter unbalance state according to claim 3 Method, which is characterized in that the upper bridge arm number of A, B, C three-phase is respectively 1,3,5, and lower bridge arm number is 4,6,2, bridge arm voltage deviation It chooses three bridge arms not in same DC bus side in governing loop to be adjusted its capacitance voltage, totally 1,2,3,2,3,4, 3,4,5,4,5,6,5,6,1,6, any one combination is chosen in 1,2 six kind of combination, will corresponding bridge arm energy adjusting to specified.
5. the zero DC voltage fault traversing controlling party of MMC under a kind of bridge arm parameter unbalance state according to claim 1 Method, which is characterized in that low-voltage module preferentially charges when submodule capacitor switching follows bridge arm module charging inside bridge arm, submodule When electric discharge, the principle switching of high-pressure modular preferential discharge.
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Families Citing this family (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109510228B (en) * 2018-10-24 2021-12-24 西安许继电力电子技术有限公司 Zero direct current voltage control method and device for MMC
CN111181187B (en) * 2018-11-12 2023-06-16 西安许继电力电子技术有限公司 MMC valve bank and switching submodule voltage equalizing control method thereof
CN109830977A (en) * 2019-04-08 2019-05-31 武汉大学 The control method of direct current transportation circuit, DC transmission system and direct current transportation circuit
CN113348615B (en) * 2019-06-25 2023-03-31 华为技术有限公司 DC-DC power converter
CN110391666B (en) * 2019-06-26 2024-05-07 中电普瑞电力工程有限公司 Mixed MMC control method, device and controller
CN110531720B (en) * 2019-09-05 2020-12-18 西南交通大学 Method for determining optimal synchronization time in MMC distributed control system
CN110688778B (en) * 2019-10-16 2021-08-31 福州大学 AC side DC bias current prediction method under asymmetric MMC bridge arm impedance
CN110943471A (en) * 2019-11-07 2020-03-31 长沙理工大学 MMC fault control strategy based on system energy optimal distribution
CN111682576B (en) * 2020-06-22 2022-02-15 哈尔滨工业大学(深圳)(哈尔滨工业大学深圳科技创新研究院) Three-phase series CA-MMC (CA-Modular multilevel converter) with direct-current fault ride-through capability in flexible direct-current power transmission system and system
CN111682575B (en) * 2020-06-22 2021-11-30 哈尔滨工业大学(深圳)(哈尔滨工业大学深圳科技创新研究院) Three-phase series CA-MMC (capacitor-multilevel converter) with voltage-stabilizing capacitor bridge arm in flexible direct current transmission system and system
CN112787528B (en) * 2020-12-30 2022-12-20 国网河北省电力有限公司沧州供电分公司 9A-MMC control method and terminal equipment
CN113595424B (en) * 2021-08-10 2022-11-01 东南大学 Bridge arm multiplexing MMC topological structure
CN113525149A (en) * 2021-08-12 2021-10-22 长春捷翼汽车零部件有限公司 Electric energy supply control method and device, electronic equipment and storage medium
CN113824338B (en) * 2021-11-09 2024-03-12 哈尔滨工业大学（深圳） Method and device for calculating asymmetric MMC bridge arm current of submodule during low-voltage ride through
CN114683850B (en) * 2021-11-19 2024-01-30 北京新能源汽车股份有限公司 Safety state control method, device and equipment

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102931863B (en) * 2012-11-12 2015-04-15 华北电力大学 Method for setting up modularized multi-level converter composite structure model
CN103532419B (en) * 2013-09-09 2016-01-20 西安交通大学 A kind of module capacitance voltage pressure equalizing control method of modularization multi-level converter
JP6334201B2 (en) * 2014-02-28 2018-05-30 株式会社日立製作所 Power converter and control method of power converter
CN104037733B (en) * 2014-06-03 2017-03-08 中国科学院电工研究所 A kind of DC Line Fault isolated form flexible direct current transmission converter station subelement topology
CN104167912B (en) * 2014-08-14 2016-08-31 华中科技大学 A kind of MMC possessing zero DC voltage fault ride-through capacity and method for designing thereof
CN204068699U (en) * 2014-09-11 2014-12-31 华南理工大学 A kind of MMC submodule with direct-current short circuit fault self-cleaning ability
CN204497991U (en) * 2015-02-04 2015-07-22 国家电网公司 A kind of autocoupling type modular multilevel high voltage direct current-direct current transformer
CN105471307A (en) * 2016-01-25 2016-04-06 华北电力大学 Auxiliary capacitor distributed type half-bridge/single-clamping series-parallel MMC automatic voltage-equalizing topology based on inequality constraint
CN105576691B (en) * 2016-03-01 2018-07-03 西安许继电力电子技术有限公司 Modularization multi-level converter DC Line Fault ride-through capability evaluation method and system
CN106099873A (en) * 2016-06-30 2016-11-09 全球能源互联网研究院 A kind of subregion interconnect device monopolar grounding fault guard method without connection transformator
CN106099968A (en) * 2016-08-05 2016-11-09 西安许继电力电子技术有限公司 Marine wind electric field DC transmission system DC short trouble traversing method and system
CN106452147B (en) * 2016-11-21 2019-02-05 西安交通大学 A kind of topology of oneself equilibrium of the MMC module capacitance voltage of three-phase symmetrical

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