CN106356880A - MMC converting system and fault-tolerant control method thereof - Google Patents
MMC converting system and fault-tolerant control method thereof Download PDFInfo
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- CN106356880A CN106356880A CN201610797502.0A CN201610797502A CN106356880A CN 106356880 A CN106356880 A CN 106356880A CN 201610797502 A CN201610797502 A CN 201610797502A CN 106356880 A CN106356880 A CN 106356880A
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- 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
- 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
- H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
- H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
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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
- H02M7/53—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 using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/537—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 using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
- H02M7/5387—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 using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
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- 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
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/30—Reactive power compensation
-
- 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)
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Abstract
The invention relates to an MMC converting system and a fault-tolerant control method thereof. The converting system comprises m*n MMC converting units which form an m*n-order matrix, wherein each MMC converting unit is one matrix unit in the matrix, the matrix units in the same column are connected sequentially, and the matrix units in the same line are connected sequentially; at least one full-bridge sub-module is arranged on each bridge arm in each MMC converting unit. The MMC converting system is divided into three layers for fault-tolerant control, the first-layer control is matrix unit fault-tolerant control, the second-layer control is matrix line fault-tolerant control, and the third-layer control is matrix column fault-tolerant control; by means of the fault-tolerant control on three levels including the matrix units, the matrix lines and the matrix columns, cross-redundant fault-tolerant control of the flexible converting system is realized, the industrial blank is filled up, the reliability of the high-voltage high-capacity flexible converting system is improved greatly, and industrial promotion is facilitated.
Description
Technical field
The present invention relates to a kind of mmc commutation system and its fault tolerant control method.
Background technology
At present, Traditional DC transmission system is (also known as line commutation inverter HVDC transmission system, line
Commutated converter based high voltage direct current, lcc-hvdc) due to its technology one-tenth
Ripe, transmission line capability is high, active power quickly be used widely by the advantage such as controlled.But, lcc-hvdc system has inversion
Stand commutation failure, weak AC system cannot be powered, need to consume the defects such as a large amount of reactive powers, in certain journey in running
Its development is restricted on degree.
With the development of electric power science and technology, the voltage source converter HVDC based on all-controlling power electronics device
Transmission of electricity (voltage source converter based high voltage direct current, vsc-hvdc) is because of it
Independent active, idle control ability, no commutation failure risk, can for passive island with power many advantages, such as obtain academia with
The favor of industrial quarters, Chinese scholar is named as Technology of HVDC based Voltage Source Converter.
Have that switching frequency is relatively low, switching loss is little based on the flexible direct current power transmission system of mmc, without alternating current filter group
The advantages of strong with autgmentability, become the main trend of flexible direct current power transmission system.But, conventional it is made up of submodule mmc
Mmc topological structure disclosed in the Chinese patent application file of flexible converter system, such as Application No. 201410400214.8,
Because the capacitance grade of single inverter is low, thus constraining its utilization in long-distance and large-capacity power transmission occasion.
Content of the invention
It is an object of the invention to provide a kind of mmc commutation system and its fault tolerant control method, in order to solve traditional flexibility
The relatively low problem of commutation system capacitance grade.
For achieving the above object, the solution of the present invention includes a kind of mmc commutation system, including m × n mmc convertor unit,
Constitute m × n rank matrix, each mmc convertor unit is the one of matrix unit in this matrix, belongs to same row
Matrix unit is sequentially connected, and the matrix unit belonging to same a line is sequentially connected；
At least one full-bridge submodule is provided with every brachium pontis in each mmc convertor unit.
Every brachium pontis in each mmc convertor unit is by full-bridge submodule and half-bridge submodule structure according to set proportion
Become.
A kind of mmc commutation system fault tolerant control method being exclusively used in above-mentioned mmc commutation system, including three layers of faults-tolerant control,
Ground floor is controlled to matrix unit faults-tolerant control, and the second layer is row matrix faults-tolerant control, and third layer is rectangular array faults-tolerant control,
Described ground floor faults-tolerant control is: the condition according to the sub-module fault rate satisfaction in matrix unit is come to matrix list
Unit is correspondingly controlled；Described sub-module fault rate be the number of fault submodule on some brachium pontis with this brachium pontis in volume
Determine the ratio of maximal submodule number putting into when DC voltage runs；
Described second layer faults-tolerant control is: when the fault brachium pontis of some matrix unit in some row matrix perfects son
When the voltage control instructions of module are more than the rated value of the first setting multiple, the described second layer are carried out to this row matrix and controls, profit
With the ability that full-bridge submodule exports negative pressure, the DC voltage of this row matrix is reduced to the second setting multiple of described rated value；
It is not have faulty submodule in the brachium pontis breaking down that described fault brachium pontis perfects submodule；
Described third layer faults-tolerant control is: the fault type according to some matrix unit in some rectangular array is to this
Commutation system is correspondingly controlled.
Realize the described condition according to the sub-module fault rate satisfaction in matrix unit correspondingly matrix unit to be carried out
The means correspondingly controlling are:
When matrix unit occurs sub-module fault, bypass fault submodule first with by-pass switch, then detect
Brachium pontis sub-module fault rate, when fault rate is less than setting value, controls and puts into redundancy submodule to replace fault submodule, it is right to make
Answer the voltage of brachium pontis output constant；Each normal submodule when fault rate is higher than described setting value, on lifting fault brachium pontis
The voltage of block output, so that this matrix unit symmetrical operation.
In described second layer faults-tolerant control, when the ability exporting negative pressure using full-bridge submodule can not be by homography row
DC voltage be reduced to described rated value second setting multiple when, control bypass all of matrix list in this row matrix
Unit.
In described second layer faults-tolerant control, the brachium pontis electricity of all of matrix unit in detection some row matrix described
Stream, and draw the bridge arm current of maximum, when maximum bridge arm current is in the current stress tolerance range of controlling switch, the change of current
System maintains former Power operation, and all of row matrix to distribute the output work of commutation system according to the ratio of respective DC voltage
Rate；When maximum bridge arm current is not in the current stress tolerance range of controlling switch, reduce the output of commutation system,
And all of row matrix is run with the peak power output allowing.
After described control bypasses all of matrix unit in this row matrix, detection perfects all of in row matrix
The bridge arm current of matrix unit, and draw the bridge arm current of maximum, when maximum bridge arm current is in the current stress of controlling switch
When in tolerance range, commutation system perfects the output work that row matrix to distribute commutation system according to the ratio of respective DC voltage
Rate；When maximum bridge arm current is not in the current stress tolerance range of controlling switch, reduce the output of commutation system,
The peak power output perfecting row matrix to allow is run；Wherein, perfecting row matrix is except being bypassed in commutation system
All of row matrix outside row matrix.
Realize the described fault type according to some matrix unit in some rectangular array this commutation system is carried out
The means correspondingly controlling are:
First, it is determined that the fault type of this matrix unit；
Then, when for open fault, this matrix unit of locking；When for short trouble, first colleague is perfected row square
Array element output voltage control is zero, and tripping colleague perfects the corresponding AC circuit breaker of column matrix unit, then controls colleague
Rectangular array matrix unit all bypasses；
Described colleague perfects column matrix unit and refers to: with the matrix unit breaking down be in same a line, be not belonging to same
Row and the matrix unit not broken down；
Described colleague rectangular array matrix unit refer to: with the matrix unit breaking down be in same a line, be not belonging to same
The matrix unit of row.
After being controlled accordingly for open fault, detect that all of colleague perfects the brachium pontis in column matrix unit
Electric current, finds the current value of maximum, when maximum current value is in controlling switch current stress tolerance range, all of colleague
Perfecting column matrix unit increases power to maintain power-balance to run, when maximum current value is resistance to beyond controlling switch current stress
During by scope, then reduce matrix commutation system output, carry out according to the maximum current that colleague perfects the permission of column matrix unit
Power transmission；
After being controlled accordingly for short trouble, detection perfects the bridge in all of matrix unit in row matrix
Arm electric current, finds the current value of maximum, when maximum current value is in controlling switch current stress tolerance range, perfects matrix
Row increases power to maintain power-balance to run；When maximum current value exceeds current stress tolerance range, then reduce matrix
Commutation system output, the peak power according to perfecting row matrix permission is transmitted；The described row matrix that perfects is change of current system
The row matrix of ffault matrix unit is not contained in system.
The size of the priority of ground floor faults-tolerant control, second layer faults-tolerant control and third layer faults-tolerant control is: ground floor
The priority of faults-tolerant control is more than the priority of second layer faults-tolerant control, and the priority of second layer faults-tolerant control is more than third layer and holds
The wrong priority controlling.
The mmc commutation system that the present invention provides is considered as a matrix on the whole, and each matrix unit is changed for a mmc
Stream device, so this commutation system, using mmc as basic convertor unit, by way of series boosting and flow increasing in parallel, constitutes square
Configuration high-voltage large-capacity flexible converter system, can realize the requirement of high-voltage large-capacity using the matrix form combination of inverter, and
And flexibly pass through control by what the full-bridge submodule in each mmc inverter realized alternating current-direct current fault；Meanwhile, matrix form group
Conjunction can improve the redundancy fault-tolerant ability of whole commutation system.
Because the research for combined type flexible DC converter is still in initial stage at present, especially for matrix form
Flexible converter system coordination control ＆ protection strategy etc., also in space state, does not more have matrix form flexible converter System Fault Tolerance control
The relevant report of system strategy, so, the commutation system that the present invention provides is significant, and can be obviously improved Large Copacity and change
The research and development progress of streaming system.
And, the matrix form mmc commutation system being provided based on the present invention, the present invention also provides a kind of dividing of this commutation system
Hierarchical redundancy fault tolerant control method, by the faults-tolerant control of matrix unit, row matrix and three levels of rectangular array it is achieved that flexibility
The crossing redundancy faults-tolerant control of commutation system, has filled up industry blank, greatly improving high-voltage large-capacity flexible converter system can
By property, industry is conducive to promote.
Brief description
Fig. 1 is the mmc commutation system overall structure diagram that the present invention provides；
Fig. 2 is the topological structure schematic diagram of half-bridge submodule；
Fig. 3 is the topological structure schematic diagram of full-bridge submodule；
Fig. 4 is overall faults-tolerant control strategic process schematic diagram；
Fig. 5 is the faults-tolerant control strategic process schematic diagram of matrix unit level；
Fig. 6 is the faults-tolerant control strategic process schematic diagram of row matrix level；
Fig. 7 is the faults-tolerant control strategic process schematic diagram of rectangular array level.
Specific embodiment
The present invention will be further described in detail below in conjunction with the accompanying drawings.
Fig. 1 gives the matrix form flexible converter system topology based on submodule mixed type mmc inverter unit, should
Topology comprises m × n submodule mixed type mmc inverter unit, and this m × n mmc inverter unit constitutes a matrix, should
Matrix unit in matrix is mmc inverter.Wherein m represents the matrix line number of matrix form commutation system, i.e. the series connection of mmc unit
Quantity, m determines the DC voltage level of matrix form commutation system；N represents the matrix columns of matrix form commutation system, i.e. mmc
The quantity in parallel of unit string, n determines the DC current grade of matrix form commutation system；M and n has together decided on the matrix form change of current
Power system capacity.
For the ease of faults-tolerant control, in each brachium pontis in each mmc inverter unit, it is provided with least one full-bridge
Submodule, further, in the present embodiment, each brachium pontis in each mmc inverter unit is by full-bridge submodule and half
Bridge submodule is constituted according to set proportion.Half-bridge submodule and full-bridge submodule with all-controlling power electronics device such as igbt are
Basis is constituted, and as shown in Figure 2 and Figure 3, wherein, t represents full-control type power electronic switching device, d representation switch device to its topological structure
Part anti-paralleled diode, behalf by-pass switch, c represents submodule DC capacitor.
Based on above-mentioned matrix form mmc commutation system, the present invention also provides a kind of faults-tolerant control side of this mmc commutation system
Method, based on matrix structure, carries out faults-tolerant control from matrix unit, row matrix and three levels of rectangular array respectively.
As shown in figure 4, giving the preferential cooperation logic between three hierarchical redundancy fault-tolerance approaches, wherein first layer
The control of submatrix unit is basis it should preferentially ensure to implement, the control of second level row matrix is first
It should suboptimum ensures to implement, the control of the 3rd level rectangular array is that fault deteriorates further for the tight fit of individual level
Fault-tolerant means, can implement last.First level, the inverter unit fault tolerant control method in matrix, thus to greatest extent
Ensure commutation system basic equipment availability, for subsequently higher level fault-tolerant offer basic guarantee；Second level, row matrix holds
Wrong control method, thus ensure the DC voltage enabling capabilities of commutation system to greatest extent；Third level, rectangular array faults-tolerant control
Method, thus ensure the DC current enabling capabilities of commutation system to greatest extent.
Hereinafter the faults-tolerant control of these three levels is illustrated respectively.
As shown in figure 5, being the flow chart of matrix unit faults-tolerant control for the first level.For any one matrix unit,
When this matrix unit occurs sub-module fault, bypass fault submodule first with by-pass switch s, then detect brachium pontis submodule
Block fault rate.Sub-module fault rate is that the number of fault submodule on some brachium pontis is transported in rated direct voltage with this brachium pontis
The ratio of the maximal submodule number putting into during row.In the present embodiment, give a computing formula of sub-module fault rate, see
Formula (1).
In formula: nsumThe maximal submodule quantity that when running for rated direct voltage, brachium pontis need to put into, nfFor fault in brachium pontis
The quantity of submodule.
When the fault submodule number on some brachium pontis is less, that is, the sub-module fault rate of this brachium pontis sets less than one
During fixed threshold value (the present embodiment is taking 5% as a example), for ensureing the fast response characteristic of commutation system after fault, according to submodule electricity
The constant principle of pressure instruction carries out the Pressure and Control that fault brachium pontis perfects submodule, that is, control and put into identical with fault submodule
The redundancy submodule of number, to replace fault submodule, makes the voltage that this brachium pontis exports constant；When the fault submodule on this brachium pontis
When number is more, when that is, the sub-module fault rate of this brachium pontis is higher than the threshold value of this setting (the present embodiment is taking 5% as a example), for preventing
The unbalanced DC voltage and current fluctuation leading to of brachium pontis energy is excessive, switchs to the submodule voltage increase based on the brachium pontis energy balance
Faults-tolerant control, that is, each being lifted on this fault brachium pontis perfects the voltage of submodule output, so that this matrix unit is symmetrically transported
OK.Wherein, fault brachium pontis perfects submodule and refers to: has in the brachium pontis of sub-module fault, remaining does not break down still just
The submodule often running.
In the present embodiment, the voltage increase perfecting submodule in fault brachium pontis instructs as shown in formula (2), thus maximum journey
Degree ensures the quick and stable redundancy fault-tolerant ability of matrix unit.
In formula: udcFor matrix unit DC operating voltage.
Such as: matrix unit will export the voltage of 100kv, and the voltage of each submodule is 2kv, then need in brachium pontis to put into
50 sub- block coupled in series, to reach the output voltage of 100kv.
When now there being sub-module fault, output voltage can be made constant by the input of redundant module.Such as one bridge
Arm has 60 submodules, then has 10 module redundancies during output 100kv voltage, when there being a sub-module fault, puts into one
The redundant module of 2kv, the voltage of output 100kv is unaffected, advantage of this is that transient response is fast；This is exactly so-called
The constant fault-tolerant strategy of submodule voltage.
But because mmc is three-phase 6 bridge arm structure, when the fault submodule in single brachium pontis is more (generally more than 5%
After), other perfect, and the normal submodule number run in phase brachium pontis is more, and the capacitance energy storage under same voltage is just high, inevitable
Lead to asymmetric storage energy operation between mmc unit brachium pontis, the consequence of asymmetric operation is exactly two double-frequency fluctuation leading to DC voltage,
Impact straight-flow system stability and control accuracy.Therefore in order to take into account that response is fast and fault submodule more after lead to mmc not right
Claim to run aggravation, propose to be lifted the voltage of fault brachium pontis submodule, although so fault brachium pontis is compared with perfecting brachium pontis,
Submodule number is few, but due to energy storage increase after single submodule voltage increase, mmc unit can recover symmetrical operation,
Avoid two double-frequency fluctuation of DC voltage.It is implemented as: to calculate lifting fault brachium pontis submodule electricity using formula (2)
Press desired value, then the submodule of this brachium pontis puts into number and removed in the result of calculation of formula (2) by 100kv, that is, put into individual
Number will reduce, and fault brachium pontis submodule can be charged to the numerical value obtaining using formula (2) in this process, therefore can sacrifice one
Fixed response characteristic.
As shown in fig. 6, being row matrix faults-tolerant control flow chart for the second level.For some row matrix, when this matrix
When some matrix unit in row breaks down, the voltage control instructions value perfecting submodule of fault brachium pontis sets more than first
Determine multiple (the present embodiment is taking 105% as a example) rated value when, this row matrix is implemented with the control of this second level.Wherein, therefore
The voltage control instructions value perfecting submodule of barrier brachium pontis can be all of voltage perfecting submodule in this fault brachium pontis
Meansigma methodss or this fault brachium pontis in all of voltage perfecting submodule in maximum, or adopt other
Mode obtains, and the present embodiment is taking meansigma methodss as a example, and provides a computing formula, such as shown in formula (3).
In above formula:Meansigma methodss for all of output voltage perfecting submodule in fault brachium pontis；∑usm_
Arm is bridge arm voltage；ntotalSum for the submodule on a brachium pontis；Lpf is low-pass first order filter, filter cutoff frequency
By 0.707 times of connection AC network fundamental frequency；nfNumber for the fault submodule on this brachium pontis.
When submodule average voltage is more than the first setting multiple (105%) of rated value, then it is in this row matrix
All of matrix unit utilizes full-bridge submodule to export the ability of negative pressure, and this row matrix DC voltage is reduced to rated value by unification
The second setting multiple (the present embodiment is taking 95% as a example), so circulate, to reduce the overvoltage bypass risk running submodule.
Meanwhile, detect the bridge arm current in all of matrix unit in this row matrix, obtain multiple current values, find it
Middle maximum bridge arm current, when maximum bridge arm current is in the current stress tolerance range of controlling switch (igbt), this changes
Streaming system is run according to original transducing power and is controlled, and all of row matrix to divide according to the ratio of respective DC voltage
Join the output of commutation system；When maximum bridge arm current is not in the current stress tolerance range of controlling switch (igbt)
When, reduce the output of commutation system, and all of row matrix is run with the peak power output allowing.Wherein, control is opened
The current stress tolerance range closing is by controlling switch, and that is, igbt determines, it is the index parameter of igbt, as long as igbt is fixed,
Its current stress tolerance range is also just fixed.
Wherein, the formula that row matrix to distribute the output of commutation system according to the ratio of respective DC voltage is following
Formula (4).
In addition, when full-bridge submodule negative pressure fan-out capability runs out, stopping DC decompression circulation；And, when beyond complete
During bridge submodule negative pressure fan-out capability, that is, when the ability exporting negative pressure using full-bridge submodule can not be by the unidirectional current of this row matrix
Second setting multiple (the present embodiment is taking 95% as a example) of the as little as above-mentioned rated value of pressure drop, controls to bypass in this row matrix and owns
Matrix unit.
Meanwhile, after control bypasses all of matrix unit in this row matrix, detection is all of to be perfected in row matrix
All of matrix unit in bridge arm current, obtain multiple current values, find maximum of which bridge arm current, when maximum bridge
When arm electric current is in the current stress tolerance range of controlling switch (igbt), commutation system is run according to original transducing power
And control, and all of perfect the output that row matrix to distribute commutation system according to the ratio of respective DC voltage；When
When big bridge arm current is not in the current stress tolerance range of controlling switch (igbt), reduce the output of commutation system,
And all of perfect row matrix to allow peak power output run.Wherein, the current stress tolerance range of controlling switch is
By controlling switch, i.e. igbt decision, it is the index parameter of igbt, as long as igbt is fixed, its current stress tolerance range is also
Fixed.
Wherein, perfect the formula that row matrix to distribute the output of commutation system according to the ratio of respective DC voltage
It is allocated according to above-mentioned formula (4).Perfect row matrix to refer to: not by the still row matrix in continuous service of integral bypass.
As shown in fig. 7, being rectangular array faults-tolerant control flow chart for third level.The thinking of the control of this rectangular array is:
Fault type according to some matrix unit in some rectangular array is correspondingly controlled to this commutation system, here
Fault type is divided into open circuit and two kinds of short circuit.
First, detect the malfunction of this rectangular array, i.e. the fault type of the ffault matrix unit in this rectangular array, when for
During open fault, this fault mmc convertor unit of locking；When for short trouble, first colleague is perfected the output of column matrix unit
Voltage is controlled to zero, and tripping colleague perfects the corresponding AC circuit breaker of column matrix unit, then controls colleague's matrix column matrix
Unit all bypasses.Wherein, colleague perfects column matrix unit and refers to: is in same a line, does not belong to the matrix unit breaking down
In same row and the matrix unit that do not break down；Colleague's rectangular array matrix unit refers to: at the matrix unit breaking down
In same a line, the matrix unit that is not belonging to same row.So, colleague's rectangular array matrix unit includes colleague and perfects column matrix list
Unit.
After being controlled accordingly for open fault, detect that whole colleagues perfect the brachium pontis in column matrix unit
Electric current, finds the current value of maximum, when this maximum current value is in controlling switch current stress tolerance range, all of same
Row perfects column matrix unit and increases power to maintain power-balance to run, and tolerates model when this maximum current value exceeds current stress
When enclosing, then reduce matrix commutation system output, carry out power according to the maximum current that colleague perfects the permission of column matrix unit
Transmission.
After being controlled accordingly for short trouble, detection perfects the bridge in all of matrix unit in row matrix
Arm electric current, finds the current value of maximum, when this maximum current value is in controlling switch current stress tolerance range, perfects square
Battle array row increases power to maintain power-balance to run；When this maximum current value exceeds current stress tolerance range, then reduce
Matrix commutation system output, the peak power according to perfecting row matrix permission is transmitted.
Hereinafter above-mentioned commutation system is illustrated with ± 1000kv/12000mw matrix form mmc the commutation system of 2 × 2
Control method.
The mmc unit of above-mentioned matrix form mmc system is 1000kv/3000mw voltage source converter, main electrical parameters
For: using the igbt device of 4500v/3000a specification, submodule block specifications be 2500v/3000a it is considered to 10% redundancy submodule
Configuration, then the submodule quantity of the single brachium pontis of mmc unit is 1000/2.5 × 1.1=440；Consider mmc unit zero unidirectional current
Pressure control ability, half-bridge submodule is 1:1 with the accounting of full-bridge submodule；The valve side zero load ac line voltage of mmc unit is effective
Value is designed as 520kv.
Carry out that the first level is fault-tolerant to be illustrated first, when on a of mmc11 there is 10 sub-module fault in brachium pontis, this
When sub-module fault rate be 10/400=2.5%, should maintain that mmc11 submodule voltage is constant to be continued to run with, put into 10 redundancies
Submodule is replacing fault submodule；When certain brachium pontis sub-module fault of mmc11 adds up as 20, that is, fault rate reaches 5%, increases
Perfect greatly the output voltage values of submodule, mmc11 fault brachium pontis will perfect submodule voltage instruction and be controlled to sqrt (400/
(400-20)) × 2500=2564.9v, whole mmc commutation system continuous service.
When mmc11 perfects, because sub-module fault increases causing trouble brachium pontis, the volume that submodule control instruction is more than 1.05 times
During definite value, it is row matrix faults-tolerant control flow process by starting the second level, now can calculate the single brachium pontis fault submodule of mmc11
Number is at least 400-400/1.05^2=38 (rounding up), and it is sqrt that fault brachium pontis now perfects submodule voltage instruction
(400/ (400-38)) × 2500=1.0512 × 2500=2627.9v；Full-bridge submodule hence with mmc11 and mmc12
Output negative voltage ability, control the first row DC voltage vdc1 is 1000 × 0.95=950kv, and now mmc12 is without son
Module failure, then its submodule voltage instruction value should be 950e3/400=2375v, and in mmc11, have 38 fault submodule bridges
The submodule voltage instruction value that perfects of arm should be sqrt (400/ (400-38)) × 2375=2496.5v；Volume according to 3000mw
Determine transducing power to calculate, now the bridge arm current stress of the first row matrix is 3000e6/950e3/3+3000e6/520e3/
1.732/2=2718.1a, not less than the igbt device current stress permissible value of 3000a, system with 3000mw × 4 can be still
12000mw oepration at full load；
When leading to the first row matrix by integral bypass due to mmc11 sub-module fault, system can only utilize the second row
Carry out power transmission, be now only capable of conveying 6000mw power, that is, system will drop volume and run.
Finally carrying out third level is that rectangular array faults-tolerant control illustrates, still, when mmc11 is open circuit taking mmc11 as a example
During fault, locking mmc11 convertor unit first；Limited by current stress, system will lose the power of half, and system maximum can
To operate under ± 1000kv/6000mw power rating；When mmc11 is for short trouble, mmc12 output DC voltage is controlled immediately
It is made as zero, the corresponding AC circuit breaker of tripping mmc12, then issue mmc12 bypass commands；Limited by current stress, system
The power of half will be lost, system maximum may operate under -1000kv/6000mw power rating.
It is presented above specific embodiment, but the present invention is not limited to described embodiment.The base of the present invention
This thinking is above-mentioned basic scheme, for those of ordinary skill in the art, according to the teachings of the present invention, designs various changes
The model of shape, formula, parameter do not need to spend creative work.Right without departing from the principles and spirit of the present invention
Change, modification, replacement and modification that embodiment is carried out still fall within protection scope of the present invention.
Claims (10)
1. a kind of mmc commutation system, it is characterised in that including m × n mmc convertor unit, constitutes m × n rank matrix, often
One mmc convertor unit is the one of matrix unit in this matrix, and the matrix unit belonging to same row is sequentially connected, and belongs to
Matrix unit with a line is sequentially connected；
At least one full-bridge submodule is provided with every brachium pontis in each mmc convertor unit.
2. mmc commutation system according to claim 1 is it is characterised in that every brachium pontis in each mmc convertor unit is equal
It is made up of according to set proportion full-bridge submodule and half-bridge submodule.
3. a kind of mmc commutation system fault tolerant control method being exclusively used in mmc commutation system described in claim 1 it is characterised in that
Including three layers of faults-tolerant control, ground floor is controlled to matrix unit faults-tolerant control, and the second layer is row matrix faults-tolerant control, and third layer is
Rectangular array faults-tolerant control,
Described ground floor faults-tolerant control is: according to the condition that the sub-module fault rate in matrix unit meets, matrix unit is entered
Row correspondingly controls；Described sub-module fault rate be the number of fault submodule on some brachium pontis with this brachium pontis specified straight
The ratio of the maximal submodule number that stream voltage puts into when running；
Described second layer faults-tolerant control is: when the fault brachium pontis of some matrix unit in some row matrix perfects submodule
Voltage control instructions be more than the first setting multiple rated value when, the described second layer is carried out to this row matrix and controls, using complete
The DC voltage of this row matrix is reduced to the second setting multiple of described rated value by the ability of bridge submodule output negative pressure；Described
It is not have faulty submodule in the brachium pontis breaking down that fault brachium pontis perfects submodule；
Described third layer faults-tolerant control is: the fault type according to some matrix unit in some rectangular array is to this change of current
System is correspondingly controlled.
4. mmc commutation system fault tolerant control method according to claim 3 it is characterised in that realize described according to matrix
The means that the condition that sub-module fault rate in unit meets correspondingly matrix unit correspondingly to be controlled are:
When matrix unit occurs sub-module fault, bypass fault submodule first with by-pass switch, then detect brachium pontis
Sub-module fault rate, when fault rate is less than setting value, controls and puts into redundancy submodule to replace fault submodule, make corresponding bridge
The voltage of arm output is constant；When fault rate is higher than described setting value, each the normal submodule on lifting fault brachium pontis is defeated
The voltage going out, so that this matrix unit symmetrical operation.
5. mmc commutation system fault tolerant control method according to claim 3 is it is characterised in that fault-tolerant in the described second layer
In control, when using full-bridge submodule export negative pressure ability the DC voltage of homography row can not be reduced to described specified
During the second setting multiple of value, control and bypass all of matrix unit in this row matrix.
6. mmc commutation system fault tolerant control method according to claim 3 is it is characterised in that fault-tolerant in the described second layer
In control, the bridge arm current of all of matrix unit in detection some row matrix described, and draw the bridge arm current of maximum,
When maximum bridge arm current is in the current stress tolerance range of controlling switch, commutation system maintains former Power operation, and institute
Some row matrixs to distribute the output of commutation system according to the ratio of respective DC voltage；When maximum bridge arm current does not exist
When in the current stress tolerance range of controlling switch, reduce the output of commutation system, and all of row matrix is to allow
Peak power output is run.
7. mmc commutation system fault tolerant control method according to claim 5 is it is characterised in that bypass in described control
After all of matrix unit in this row matrix, detection perfects the bridge arm current of all of matrix unit in row matrix, and
Go out the bridge arm current of maximum, when maximum bridge arm current is in the current stress tolerance range of controlling switch, commutation system is good for
Complete matrix row to distribute the output of commutation system according to the ratio of respective DC voltage；When maximum bridge arm current is not in control
When in the current stress tolerance range of system switch, reduce the output of commutation system, the maximum perfecting row matrix to allow is defeated
Go out Power operation；Wherein, perfecting row matrix is all of row matrix in addition to the row matrix being bypassed in commutation system.
8. mmc commutation system fault tolerant control method according to claim 3 it is characterised in that realize described according to a certain
The means that the fault type of some matrix unit in individual rectangular array is correspondingly controlled to this commutation system are:
First, it is determined that the fault type of this matrix unit；
Then, when for open fault, this matrix unit of locking；When for short trouble, first colleague is perfected column matrix list
First output voltage control is zero, and tripping colleague perfects the corresponding AC circuit breaker of column matrix unit, then controls same row matrix
Column matrix unit all bypasses；
Described colleague perfects column matrix unit and refers to: with the matrix unit breaking down be in same a line, be not belonging to same row and
The matrix unit not broken down；
Described colleague's rectangular array matrix unit refers to: is in same a line, is not belonging to same row with the matrix unit breaking down
Matrix unit.
9. mmc commutation system fault tolerant control method according to claim 8 it is characterised in that
After being controlled accordingly for open fault, detect that all of colleague perfects the electricity of the brachium pontis in column matrix unit
Stream, finds the current value of maximum, and when maximum current value is in controlling switch current stress tolerance range, all of colleague is good for
Full column matrix unit increases power to maintain power-balance to run, and tolerates when maximum current value exceeds controlling switch current stress
During scope, then reduce matrix commutation system output, carry out work(according to the maximum current that colleague perfects the permission of column matrix unit
Rate is transmitted；
After being controlled accordingly for short trouble, detection perfects the brachium pontis electricity in all of matrix unit in row matrix
Stream, finds the current value of maximum, when maximum current value is in controlling switch current stress tolerance range, perfects row matrix and increases
Plus power is to maintain power-balance to run；When maximum current value exceeds current stress tolerance range, then reduce the matrix change of current
System output power, the peak power according to perfecting row matrix permission is transmitted；The described row matrix that perfects is in commutation system
Row matrix without ffault matrix unit.
10. mmc commutation system fault tolerant control method according to claim 3 it is characterised in that ground floor faults-tolerant control,
The size of the priority of second layer faults-tolerant control and third layer faults-tolerant control is: the priority of ground floor faults-tolerant control is more than second
The priority of layer faults-tolerant control, the priority of second layer faults-tolerant control is more than the priority of third layer faults-tolerant control.
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