CN205754045U - The centralized half-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology - Google Patents

Abstract

This utility model provides the centralized half-bridge MMC of auxiliary capacitor based on equality constraint from all pressing topology.Half-bridge MMC is from all pressing topology, by half-bridge MMC model with from all pressure subsidiary loop joint mappings.Half-bridge MMC model and 6 in all pressure subsidiary loop is by subsidiary loopNIndividual mechanical switch generation electrical link, mechanical switch closes, and both constitute the centralized half-bridge MMC of auxiliary capacitor based on equality constraint and certainly all press topology, mechanical switch to open, and topoligical equivalence is half-bridge MMC topology.In the case of not emphasizing two kinds of topological variations, 6 in all pressure subsidiary loopsNIndividual mechanical switch can omit, and substitutes with wire, directly constitutes the centralized half-bridge MMC of auxiliary capacitor based on equality constraint from all pressing topology.This half-bridge MMC is from all pressing topology, do not rely on special Pressure and Control, it is possible on the basis of completing the conversion of orthogonal stream energy, spontaneously realize the equilibrium of submodule capacitor voltage, submodule can be reduced simultaneously accordingly and trigger frequency and capacitor's capacity, it is achieved the fundamental frequency modulation of half-bridge MMC.

Description

The centralized half-bridge of auxiliary capacitor based on equality constraint MMC From all pressing topology

Technical field

This utility model relates to flexible transmission field, is specifically related to a kind of centralized half-bridge MMC of auxiliary capacitor based on equality constraint from all pressing topology.

Background technology

Modularization multi-level converter MMC is the developing direction of following HVDC Transmission Technology, MMC uses submodule (Sub-module, SM) mode cascaded constructs converter valve, avoid the direct series connection of big metering device, reduce requirement conforming to device, simultaneously facilitate dilatation and redundant configuration.Along with the rising of level number, output waveform, close to sinusoidal, can effectively avoid the defect of low level VSC-HVDC.

Half-bridge MMC is combined by half-bridge submodule, and half-bridge submodule is made up of 2 IGBT module, 1 sub-module capacitance, 1 IGCT and 1 mechanical switch, and low cost, running wastage is little.

Different from two level, three level VSC, the DC voltage of half-bridge MMC is not supported by a bulky capacitor, but is supported by a series of separate suspension submodule capacitances in series.In order to ensure that the waveform quality that AC voltage exports bears identical stress with each power semiconductor in guarantee module, also for preferably supporting DC voltage, reduce alternate circulation, it is necessary to assure submodule capacitor voltage is in the state of dynamic stability at the periodic current disorder of internal organs of brachium pontis power.

Sequence based on capacitance voltage sequence all presses algorithm to be to solve the main flow thinking of half-bridge submodule capacitor voltage equalization problem in half-bridge MMC at present, the good all pressures effect of this scheme can be verified in emulation and practice, but is also constantly expose its some inherent shortcomings.First, the realization of ranking function has to rely on the Millisecond sampling of capacitance voltage, needs substantial amounts of sensor and optical-fibre channel to be coordinated；Secondly, when half-bridge submodule number increases, the operand of capacitance voltage sequence increases rapidly, and the hardware designs for controller brings huge challenge；Additionally, submodule is cut-off frequency and has the highest requirement by sequence all realizations of pressure algorithm, cut-off frequency and be closely related with all pressure effects, in practice process, probably due to all press the restriction of effect, it has to improve the triggering frequency of submodule, and then bring the increase that inverter is lost.

Document " A DC-Link Voltage Self-Balance Method for a Diode-Clamped Modular Multilevel Converter With Minimum Number of Voltage Sensors ", it is proposed that a kind of rely on clamp diode and transformator to realize MMC submodule capacitor voltage equilibrium thinking.But the program the most to a certain degree destroys the modular nature of submodule, submodule capacitive energy interchange channel is also confined in mutually, could not make full use of the existing structure of MMC, introducing of three transformators also brings along bigger improvement cost while making control strategy complicate.

Utility model content

For the problems referred to above, the purpose of this utility model is to propose a kind of economy, modular, is independent of all pressing algorithm, can reduce submodule simultaneously accordingly and trigger the half-bridge MMC of frequency and capacitor's capacity from all pressing topology.

The concrete constituted mode of this utility model is as follows.

The centralized half-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, and including the half-bridge MMC model being made up of A, B, C three-phase, A, B, C three-phase is respectively by 2NIndividual half-bridge submodule, 2 brachium pontis reactors are in series；Including by 6NIndividual mechanical switch, 6N+ 5 clamp diodes, 2 auxiliary capacitors, 2 auxiliary IGBT module compositions from the most all pressing subsidiary loop.

The above-mentioned centralized half-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, 1st submodule of brachium pontis in A phase, its submodule electric capacity negative pole is connected with the 2nd of brachium pontis module I GBT module midpoint in A phase downwards, and its submodule IGBT module midpoint is upwards connected with dc bus positive pole；In A phase the of brachium pontisiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacity negative pole is downwards with in A phase the of brachium pontisi+ 1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is upwards with in A phase the of brachium pontisi-1 sub-module capacitance negative pole is connected；In A phase the of brachium pontisNIndividual submodule, its submodule electric capacity negative pole is connected down through the 1st sub-module I GBT module midpoint of the lower brachium pontis of two brachium pontis reactors and A phase, and its submodule IGBT module midpoint is upwards with in A phase the of brachium pontisN-1 sub-module capacitance negative pole is connected；The of the lower brachium pontis of A phaseiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacity negative pole downwards with the of A phase time brachium pontisi+ 1 sub-module I GBT module midpoint is connected, the of its IGBT module midpoint upwards brachium pontis lower with A phasei-1 sub-module capacitance negative pole is connected；The of the lower brachium pontis of A phaseNIndividual submodule, its submodule electric capacity negative pole is connected with dc bus negative pole downwards, the of its submodule IGBT module midpoint upwards brachium pontis lower with A phaseN-1 sub-module capacitance negative pole is connected；1st submodule of brachium pontis in B phase, its submodule capacitance cathode is upwards connected with dc bus positive pole, and its submodule IGBT module midpoint is connected with the 2nd sub-module capacitance positive pole of brachium pontis in B phase downwards；In B phase the of brachium pontisiIndividual submodule, whereiniValue be 2～N-1, its submodule capacitance cathode is upwards with in B phase the of brachium pontisi-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is downwards with in B phase the of brachium pontisi+ 1 sub-module capacitance positive pole is connected；In B phase the of brachium pontisNIndividual submodule, its submodule capacitance cathode is upwards with in B phase the of brachium pontisN-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is connected down through the 1st sub-module capacitance positive pole of the lower brachium pontis of two brachium pontis reactors and B phase；The of the lower brachium pontis of B phaseiIndividual submodule, whereiniValue be 2～N-1, the of its submodule capacitance cathode upwards brachium pontis lower with B phasei-1 sub-module I GBT module midpoint is connected, its submodule IGBT module midpoint downwards with the of B phase time brachium pontisi+ 1 sub-module capacitance positive pole is connected；The of the lower brachium pontis of B phaseNIndividual submodule, its submodule capacitance cathode upwards brachium pontis lower with B phase theN-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is connected with dc bus negative pole downwards；The connected mode of C phase upper and lower bridge arm submodule is consistent with A phase or B.

The above-mentioned centralized half-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, and in all pressure subsidiary loops, first auxiliary capacitor positive pole connection auxiliary IGBT module negative pole connects clamp diode and be incorporated to dc bus positive pole；Second auxiliary capacitor negative pole connects auxiliary IGBT module positive pole connection clamp diode and is incorporated to dc bus negative pole.Clamp diode, by the 1st sub-module capacitance and first auxiliary capacitor positive pole in brachium pontis in mechanical switch connection A phase；The is connected in A phase in brachium pontis by mechanical switchiIndividual sub-module capacitance and thei+ 1 sub-module capacitance positive pole, whereiniValue be 1～N-1；The is connected in A phase in brachium pontis by mechanical switchNIndividual sub-module capacitance brachium pontis 1st sub-module capacitance positive pole lower with A phase；The is connected in the lower brachium pontis of A phase by mechanical switchiThe lower brachium pontis of individual sub-module capacitance and A phase thei+ 1 sub-module capacitance positive pole, wherein the value of i be 1～N-1；The is connected in the lower brachium pontis of A phase by mechanical switchNIndividual sub-module capacitance and second auxiliary capacitor positive pole.Clamp diode, by the 1st sub-module capacitance and first auxiliary capacitor negative pole in brachium pontis in mechanical switch connection B phase；The is connected in B phase in brachium pontis by mechanical switchiIndividual sub-module capacitance and thei+ 1 sub-module capacitance negative pole, whereiniValue be 1～N-1；The is connected in B phase in brachium pontis by mechanical switchNIndividual sub-module capacitance brachium pontis 1st sub-module capacitance negative pole lower with B phase；The is connected in the lower brachium pontis of B phase by mechanical switchiThe lower brachium pontis of individual sub-module capacitance and B phase thei+ 1 sub-module capacitance negative pole, whereiniValue be 1～N-1；The is connected in the lower brachium pontis of B phase by mechanical switchNIndividual sub-module capacitance and second auxiliary capacitor negative pole.The annexation of C phase clamp diode is corresponding with the annexation of its submodule.

Accompanying drawing explanation

Fig. 1 is the structural representation of half-bridge submodule；

Fig. 2 is that the centralized half-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology.

Detailed description of the invention

For of the present utility model performance and operation principle are expanded on further, it is specifically described with operation principle to the constituted mode of utility model below in conjunction with accompanying drawing.But half-bridge MMC based on this principle is not limited to Fig. 2 from all pressure topologys.

With reference to Fig. 2, the centralized half-bridge MMC of auxiliary capacitor based on equality constraint from all pressing topology, including the half-bridge MMC model being made up of A, B, C three-phase, each brachium pontis of A, B, C three-phase respectively byNIndividual half-bridge submodule and 1 brachium pontis reactor are in series；Including by 6NIndividual mechanical switch, 6N+ 5 clamp diodes, 2 auxiliary capacitors, 2 auxiliary IGBT module compositions from the most all pressing subsidiary loop.

In half-bridge MMC model, the 1st submodule of brachium pontis, its submodule electric capacity in A phaseC _{­au­_1}Negative pole is connected with the 2nd of brachium pontis module I GBT module midpoint in A phase downwards, and its submodule IGBT module midpoint is upwards connected with dc bus positive pole；In A phase the of brachium pontisiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacityC­ _{au­_i} Negative pole is downwards with in A phase the of brachium pontisi+ 1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is upwards with in A phase the of brachium pontisi-1 sub-module capacitanceC­_{au­_i-1}Negative pole is connected；In A phase the of brachium pontisNIndividual submodule, its submodule electric capacityC _{­au­_N} Negative pole is down through two brachium pontis reactorsL ₀1st sub-module I GBT module midpoint of brachium pontis lower with A phase is connected, and its submodule IGBT module midpoint is upwards with in A phase the of brachium pontisN-1 sub-module capacitanceC _{­ au­_N-1}Negative pole is connected；The of the lower brachium pontis of A phaseiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacityC­_{al­_i} Negative pole downwards with the of A phase time brachium pontisi+ 1 sub-module I GBT module midpoint is connected, the of its IGBT module midpoint upwards brachium pontis lower with A phasei-1 sub-module capacitanceC _{­al­_i-1}Negative pole is connected；The of the lower brachium pontis of A phaseNIndividual submodule, its submodule electric capacityC _{­al_N} Negative pole is connected with dc bus negative pole downwards, the of its submodule IGBT module midpoint upwards brachium pontis lower with A phaseN-1 sub-module capacitanceC _{­al­_N-1}Negative pole is connected；1st submodule of brachium pontis, its submodule electric capacity in B phaseC­ _{bu­_1}Positive pole is upwards connected with dc bus positive pole, its submodule IGBT module midpoint downwards with the 2nd sub-module capacitance of brachium pontis in B phaseC­_{bu­_2}Positive pole is connected；In B phase the of brachium pontisiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacityC­_{bu­_i} Positive pole is upwards with in B phase the of brachium pontisi-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is downwards with in B phase the of brachium pontisi+ 1 sub-module capacitanceC­ _{bu­_i+1}Positive pole is connected；In B phase the of brachium pontisNIndividual submodule, its submodule electric capacityC _{­ bu­_N} Positive pole is upwards with in B phase the of brachium pontisN-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is down through two brachium pontis reactorsL ₀1st sub-module capacitance of brachium pontis lower with B phaseC _{­bl­_1}Positive pole is connected；The of the lower brachium pontis of B phaseiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacityC­ _{bl_i} The of positive pole upwards brachium pontis lower with B phasei-1 sub-module I GBT module midpoint is connected, its submodule IGBT module midpoint downwards with the of B phase time brachium pontisi+ 1 sub-module capacitanceC­ _{bl­_i+1}Positive pole is connected；The of the lower brachium pontis of B phaseNIndividual submodule, its submodule electric capacityC­_{bl_N} Positive pole upwards brachium pontis lower with B phase theN-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is connected with dc bus negative pole downwards.The connected mode of C phase upper and lower bridge arm submodule is consistent with A.

From all pressing in subsidiary loop, auxiliary capacitorC ₁Positive pole connects auxiliary IGBT moduleT ₁, negative pole connects clamp diode and is incorporated to dc bus positive pole；Auxiliary capacitorC ₂Negative pole connects auxiliary IGBT moduleT ₂, positive pole connects clamp diode and is incorporated to dc bus negative pole.Clamp diode, passes through mechanical switchK _{au_13}1st sub-module capacitance in brachium pontis in connection A phaseC­ _{au­_1}With auxiliary capacitorC ₁Positive pole；Pass through mechanical switchK _{au_i3}、K _{au_ ( i +1 ) 3}Connect in A phase in brachium pontis theiIndividual sub-module capacitanceC­_{au­_i} Withi+ 1 sub-module capacitanceC­_{au­_i+1}Positive pole, whereiniValue be 1～N-1；Pass through mechanical switchK _{au_N3}、K _{al_13}Connect in A phase in brachium pontis theNIndividual sub-module capacitanceC _{­au­_N} Brachium pontis 1st sub-module capacitance lower with A phaseC­_{al­_1}Positive pole；Pass through mechanical switchK _{al_i3}、K _{al_ ( i +1 ) 3}Connect in the lower brachium pontis of A phase theiIndividual sub-module capacitanceC _{­al­_i} Brachium pontis lower with A phase thei+ 1 sub-module capacitanceC _{­al­_i+1}Positive pole, whereiniValue be 1～N-1；Pass through mechanical switchK _{al_N3}Connect in the lower brachium pontis of A phase theNIndividual sub-module capacitanceC­_{al_N} With auxiliary capacitorC ₂Positive pole.Clamp diode, passes through mechanical switchK _{bu_13}1st sub-module capacitance in brachium pontis in connection B phaseC _{­bu­_1}With auxiliary capacitorC ₁Negative pole；Pass through mechanical switchK _{bu_i3}、K _{bu_ ( i +1 ) 3}Connect in B phase in brachium pontis theiIndividual sub-module capacitanceC­_{bu­_i} Withi+ 1 sub-module capacitanceC _{­bu­_i+1}Negative pole, whereiniValue be 1～N-1；Pass through mechanical switchK _{bu_N3}、K _{bl_13}Connect in B phase in brachium pontis theNIndividual sub-module capacitanceC _{­bu­_N} Brachium pontis 1st sub-module capacitance lower with B phaseC _{­bl­_1}Negative pole；Pass through mechanical switchK _{bl_i3}、K _{bl_ ( i +1 ) 3}Connect in the lower brachium pontis of B phase theiIndividual sub-module capacitanceC _{­ bl­_i} Brachium pontis lower with B phase thei+ 1 sub-module capacitanceC _{­bl­_i+1}Negative pole, whereiniValue be 1～N-1；Pass through mechanical switchK _{bl_N3}Connect in the lower brachium pontis of B phase theNIndividual sub-module capacitanceC­_{bl­_N} With auxiliary capacitorC ₂Negative pole.The annexation of C phase clamp diode is consistent with A.

From all pressing in subsidiary loop 6NIndividual mechanical switchK _{au_i3}、K _{al_i3}、K _{bu_i3}、K _{bl_i3}、K _{cu_i3}、K _{cl_i3}Normally closed, whereiniValue be 1～N.First sub-module capacitance of brachium pontis in A phaseC­_{au­_1}During bypass, now assist IGBT moduleT ₁Disconnect, submodule electric capacityC _{­au­_1}With auxiliary capacitorC ₁In parallel by clamp diode；Brachium pontis in A phaseiIndividual sub-module capacitanceC _{­ au­_i} During bypass, whereiniValue be 2～N, submodule electric capacityC­_{au­_i} With submodule electric capacityC­_{au­_i-1}In parallel by clamp diode；Lower first the sub-module capacitance of brachium pontis of A phaseC­ _{al_1}During bypass, submodule electric capacityC­ _{al­_1}By clamp diode, two brachium pontis reactorsL ₀With submodule electric capacityC­_{au­_N} In parallel；The lower brachium pontis of A phase theiIndividual sub-module capacitanceC­_{al_i} During bypass, whereiniValue be 2～N, submodule electric capacityC _{­al­_i} With submodule electric capacityC­ _{al_i-1}In parallel by clamp diode；Auxiliary IGBT moduleT ₂During Guan Bi, auxiliary capacitorC ₂By clamp diode and submodule electric capacityC _{­al_N} In parallel.

From all pressing in subsidiary loop 6NIndividual mechanical switchK _{au_i3}、K _{al_i3}、K _{bu_i3}、K _{bl_i3}、K _{cu_i3}、K _{cl_i3}Normally closed, whereiniValue be 1～N.Auxiliary IGBT moduleT ₁During Guan Bi, auxiliary capacitorC ₁With submodule electric capacityC­_{bu­_1}In parallel by clamp diode；Brachium pontis in B phaseiIndividual sub-module capacitanceC­_{bu­_i} During bypass, whereiniValue be 1～N-1, submodule electric capacityC­_{bu­_i} With submodule electric capacityC­_{bu­_i+1}In parallel by clamp diode；Brachium pontis in B phaseNIndividual sub-module capacitanceC­_{bu_N} During bypass, submodule electric capacityC­ _{bu­_N} By clamp diode, two brachium pontis reactorsL ₀With submodule electric capacityC­ _{bl­_1}In parallel；The lower brachium pontis of B phase theiIndividual sub-module capacitanceC­_{bl_i} During bypass, whereiniValue be 1～N-1, submodule electric capacityC­_{bl­_i} With submodule electric capacityC­ _{bl_i+1}In parallel by clamp diode；The lower brachium pontis of B phaseNIndividual sub-module capacitanceC­_{bl_N} During bypass, submodule electric capacityC _{­bl­_N} With auxiliary capacitorC­ ₂In parallel by clamp diode.

Above-mentioned auxiliary IGBT moduleT ₁" logic and " that trigger first submodule triggering signal of signal and brachium pontis in A, C phase consistent；Auxiliary IGBT moduleT ₂The lower brachium pontis of triggering signal and B phase theNThe triggering signal of individual submodule is consistent.During orthogonal stream energy is changed, each submodule alternately puts into, bypass, assists IGBT moduleT ₁、T ₂Being alternately closed, turn off, between A, B phase upper and lower bridge arm, capacitance voltage is under the effect of clamp diode, column constraint under meeting:

It follows that half-bridge MMC is in the dynamic process completing the conversion of orthogonal stream energy, meet following constraints:

Constraints that C, B the are alternate constraints alternate with A, B is consistent.

Being illustrated from above-mentioned, this half-bridge MMC topology possesses submodule capacitor voltage from the ability of equalization.

Finally should be noted that: described embodiment is only some embodiments of the present application rather than whole embodiments.Based on the embodiment in the application, the every other embodiment that those of ordinary skill in the art are obtained under not making creative work premise, broadly fall into the scope of the application protection.

Claims (6)

1. the centralized half-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, it is characterised in that: including the half-bridge MMC model being made up of A, B, C three-phase, A, B, C three-phase is respectively by 2NIndividual half-bridge submodule, 2 brachium pontis reactors are in series；Including by 6NIndividual mechanical switch, 6N+ 5 clamp diodes, 2 auxiliary capacitorsC ₁、C ₂, 2 auxiliary IGBT moduleT ₁、T ₂Constitute the most all presses subsidiary loop.

2. according to the centralized half-bridge MMC of auxiliary capacitor based on equality constraint described in right 1 from all pressing topology, it is characterised in that: the 1st submodule of brachium pontis, its submodule electric capacity in A phaseC _{­au­_1}Negative pole is connected with the 2nd of brachium pontis module I GBT module midpoint in A phase downwards, and its submodule IGBT module midpoint is upwards connected with dc bus positive pole；In A phase the of brachium pontisiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacityC­ _{au­_i} Negative pole is downwards with in A phase the of brachium pontisi+ 1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is upwards with in A phase the of brachium pontisi-1 sub-module capacitanceC­_{au­_i-1}Negative pole is connected；In A phase the of brachium pontisNIndividual submodule, its submodule electric capacityC _{­au­_N}Negative pole is down through two brachium pontis reactorsL ₀1st sub-module I GBT module midpoint of brachium pontis lower with A phase is connected, and its submodule IGBT module midpoint is upwards with in A phase the of brachium pontisN-1 sub-module capacitanceC _{­ au­_N-1}Negative pole is connected；The of the lower brachium pontis of A phaseiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacityC­_{al­_i} Negative pole downwards with the of A phase time brachium pontisi+ 1 sub-module I GBT module midpoint is connected, the of its IGBT module midpoint upwards brachium pontis lower with A phasei-1 sub-module capacitanceC _{­al­_i-1}Negative pole is connected；The of the lower brachium pontis of A phaseNIndividual submodule, its submodule electric capacityC _{­al_N} Negative pole is connected with dc bus negative pole downwards, the of its submodule IGBT module midpoint upwards brachium pontis lower with A phaseN-1 sub-module capacitanceC _{­al­_N-1}Negative pole is connected；1st submodule of brachium pontis, its submodule electric capacity in B phaseC­ _{bu­_1}Positive pole is upwards connected with dc bus positive pole, its submodule IGBT module midpoint downwards with the 2nd sub-module capacitance of brachium pontis in B phaseC­_{bu­_2}Positive pole is connected；In B phase the of brachium pontisiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacityC­_{bu­_i} Positive pole is upwards with in B phase the of brachium pontisi-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is downwards with in B phase the of brachium pontisi+ 1 sub-module capacitanceC­ _{bu­_i+1}Positive pole is connected；In B phase the of brachium pontisNIndividual submodule, its submodule electric capacityC _{­ bu­_N} Positive pole is upwards with in B phase the of brachium pontisN-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is down through two brachium pontis reactorsL ₀1st sub-module capacitance of brachium pontis lower with B phaseC _{­bl­_1}Positive pole is connected；The of the lower brachium pontis of B phaseiIndividual submodule, whereiniValue be 2～N-1, its submodule electric capacityC­ _{bl_i} The of positive pole upwards brachium pontis lower with B phasei-1 sub-module I GBT module midpoint is connected, its submodule IGBT module midpoint downwards with the of B phase time brachium pontisi+ 1 sub-module capacitanceC­ _{bl­_i+1}Positive pole is connected；The of the lower brachium pontis of B phaseNIndividual submodule, its submodule electric capacityC­_{bl_N} Positive pole upwards brachium pontis lower with B phase theN-1 sub-module I GBT module midpoint is connected, and its submodule IGBT module midpoint is connected with dc bus negative pole downwards；The connected mode of C phase upper and lower bridge arm submodule can be consistent with A, it is also possible to consistent with B；At A, B, C phase upper and lower bridge armiMechanical switch it is parallel with respectively between the output lead up and down of individual submoduleK _{au_i1}、K _{al_i1}、K _{bu_i1}、K _{bl_i1}、K _{cu_i1}、K _{cl_i1}, and IGCTK _{au_i2}、K _{al_i2}、K _{bu_i2}、K _{bl_i2}、K _{cu_i2}、K _{cl_i2}, whereiniValue be 1～N；A, B, C three-phase status that above-mentioned annexation is constituted is consistent, and other topologys after three-phase symmetrized in turn are in interest field.

3. according to the centralized half-bridge MMC of auxiliary capacitor based on equality constraint described in right 1 from all pressing topology, it is characterised in that: in all pressure subsidiary loops, auxiliary capacitorC ₁Positive pole connects auxiliary IGBT moduleT ₁, negative pole connects clamp diode and is incorporated to dc bus positive pole；Auxiliary capacitorC ₂Negative pole connects auxiliary IGBT moduleT ₂, positive pole connects clamp diode and is incorporated to dc bus negative pole；Clamp diode, passes through mechanical switchK _{au_13}1st sub-module capacitance in brachium pontis in connection A phaseC­ _{au­_1}With auxiliary capacitorC ₁Positive pole；Pass through mechanical switchK _{au_i3}、K _{au_ (i+1 ) 3}Connect in A phase in brachium pontis theiIndividual sub-module capacitanceC­_{au­_i} Withi+ 1 sub-module capacitanceC­_{au­_i+1}Positive pole, whereiniValue be 1～N-1；Pass through mechanical switchK _{au_N3}、K _{al_13}Connect in A phase in brachium pontis theNIndividual sub-module capacitanceC _{­au­_N} Brachium pontis 1st sub-module capacitance lower with A phaseC­_{al­_1}Positive pole；Pass through mechanical switchK _{al_i3}、K _{al_ (i+1 ) 3}Connect in the lower brachium pontis of A phase theiIndividual sub-module capacitanceC _{­al­_i} Brachium pontis lower with A phase thei+ 1 sub-module capacitanceC _{­al­_i+1}Positive pole, whereiniValue be 1～N-1；Pass through mechanical switchK _{al_N3}Connect in the lower brachium pontis of A phase theNIndividual sub-module capacitanceC­_{al_N} With auxiliary capacitorC ₂Positive pole；Clamp diode, passes through mechanical switchK _{bu_13}1st sub-module capacitance in brachium pontis in connection B phaseC _{­bu­_1}With auxiliary capacitorC ₁Negative pole；Pass through mechanical switchK _{bu_i3}、K _{bu_ (i+1 ) 3}Connect in B phase in brachium pontis theiIndividual sub-module capacitanceC­_{bu­_i} Withi+ 1 sub-module capacitanceC _{­bu­_i+1}Negative pole, whereiniValue be 1～N-1；Pass through mechanical switchK _{bu_N3}、K _{bl_13}Connect in B phase in brachium pontis theNIndividual sub-module capacitanceC _{­bu­_N} Brachium pontis 1st sub-module capacitance lower with B phaseC _{­bl­_1}Negative pole；Pass through mechanical switchK _{bl_i3}、K _{bl_ (i+1 ) 3}Connect in the lower brachium pontis of B phase theiIndividual sub-module capacitanceC _{­ bl­_i} Brachium pontis lower with B phase thei+ 1 sub-module capacitanceC _{­bl­_i+1}Negative pole, whereiniValue be 1～N-1；Pass through mechanical switchK _{bl_N3}Connect in the lower brachium pontis of B phase theNIndividual sub-module capacitanceC­_{bl­_N} With auxiliary capacitorC ₂Negative pole；The annexation of C phase clamp diode is corresponding with the annexation of its submodule；In above-mentioned A, B, C three-phase 6NIndividual mechanical switchK _{au_i3}、K _{al_i3}、K _{bu_i3}、K _{bl_i3}、K _{cu_i3}、K _{cl_i3}, whereiniValue be 1～N, 6N+ 5 clamp diodes, 2 auxiliary capacitorsC ₁、C ₂, and 2 auxiliary IGBT moduleT ₁、T ₂, collectively form from all pressing subsidiary loop.

4. according to the centralized half-bridge MMC of auxiliary capacitor based on equality constraint described in right 1 from the most all pressing topology, it is characterised in that: in the most all pressure subsidiary loops 6NIndividual mechanical switchK _{au_i3}、K _{al_i3}、K _{bu_i3}、K _{bl_i3}、K _{cu_i3}、K _{cl_i3}Normally closed, whereiniValue be 1～N, first sub-module capacitance of brachium pontis in A phaseC­_{au­_1}During bypass, now assist IGBT moduleT ₁Disconnect, submodule electric capacityC­ _{au­_1}With auxiliary capacitorC ₁In parallel by clamp diode；Brachium pontis in A phaseiIndividual sub-module capacitanceC­_{au­_i} During bypass, whereiniValue be 2～N, submodule electric capacityC­_{au­_i} With submodule electric capacityC­_{au­_i-1}In parallel by clamp diode；Lower first the sub-module capacitance of brachium pontis of A phaseC _{­al_1}During bypass, submodule electric capacityC­_{al­_1}By clamp diode, two brachium pontis reactorsL ₀With submodule electric capacityC­ _{au­_N} In parallel；The lower brachium pontis of A phase theiIndividual sub-module capacitanceC _{­al_i} During bypass, whereiniValue be 2～N, submodule electric capacityC­_{al­_i} With submodule electric capacityC­_{al_i-1}In parallel by clamp diode；Auxiliary IGBT moduleT ₂During Guan Bi, auxiliary capacitorC ₂By clamp diode and submodule electric capacityC _{­al_N} In parallel；Auxiliary IGBT moduleT ₁During Guan Bi, auxiliary capacitorC ₁With submodule electric capacityC­_{bu­_1}In parallel by clamp diode；Brachium pontis in B phaseiIndividual sub-module capacitanceC­_{bu­_i} During bypass, whereiniValue be 1～N-1, submodule electric capacityC­_{bu­_i} With submodule electric capacityC­_{bu­_i+1}In parallel by clamp diode；Brachium pontis in B phaseNIndividual sub-module capacitanceC­_{bu_N} During bypass, submodule electric capacityC­ _{bu­_N} By clamp diode, two brachium pontis reactorsL ₀With submodule electric capacityC­ _{bl­_1}In parallel；The lower brachium pontis of B phase theiIndividual sub-module capacitanceC­_{bl_i} During bypass, whereiniValue be 1～N-1, submodule electric capacityC­_{bl­_i} With submodule electric capacityC­ _{bl_i+1}In parallel by clamp diode；The lower brachium pontis of B phaseNIndividual sub-module capacitanceC­_{bl_N} During bypass, submodule electric capacityC _{­bl­_N} With auxiliary capacitorC­ ₂In parallel by clamp diode；Wherein assist IGBT moduleT ₁" logic and " that trigger first submodule triggering signal of signal and brachium pontis in A, C phase consistent；Auxiliary IGBT moduleT ₂The lower brachium pontis of triggering signal and B phase theNThe triggering signal of individual submodule is consistent；During orthogonal stream energy is changed, each submodule alternately puts into, bypass, assists IGBT moduleT ₁、T ₂Being alternately closed, turn off, A phase upper and lower bridge arm submodule capacitor voltage, under the effect of clamp diode, meets lower column constraint,U _{C 1}≥U _{C ­au_1}≥U _{C ­au_2}…≥U _{C ­au_N} ≥U _{C ­al_1}≥U _{C ­al_2}…≥U _{C ­al_N} ≥U _{C 2}；B phase upper and lower bridge arm submodule capacitor voltage, under the effect of clamp diode, meets lower column constraint,U _{C 1}≤U _{C ­bu_1}≤U _{C ­bu_2}…≤U _{C ­bu_N} ≤U _{C ­bl_1}≤U _{C ­bl_2}…≤U _{C ­bl_N} ≤U _{C 2}；The centralized half-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, in dynamic process, and auxiliary capacitorC ₁Both can be as the highest electric capacity of A phase voltage, again can be as the minimum electric capacity of B phase voltage；Auxiliary capacitorC ₂Both can be as the minimum electric capacity of A phase voltage, again can be as the highest electric capacity of B phase voltage；Against two equality constraints, max(U _{C a­})=min(U _{C b}), min(U _{C a})=max(U _{C b}), in A, B phase upper and lower bridge arm 4NIndividual sub-module capacitance,C _{au_i} 、C_{al_i} 、C _{bu_i} 、C _{bl_i} , whereiniValue be 1～N, and auxiliary capacitorC ₁、C ₂, voltage be in self-balancing state, A, B are alternate possesses submodule capacitor voltage from the ability of equalization for topology；If the form of the composition of C phase is consistent with A in topology, then the constraints of C, B capacitive coupling voltage is consistent with capacitance voltage constraints between A, B；If the form of the composition of C phase is consistent with B in topology, then the constraints of A, C capacitive coupling voltage is consistent with capacitance voltage constraints between A, B, and topology possesses submodule capacitor voltage from the ability of equalization；In utilizing clamp diode to realize mutually between adjacent submodule on the basis of capacitive energy single-phase flow, rely on equality constraint max(between auxiliary capacitor voltageU _{C a­})=min(U _{C b}), min(U _{C a})=max(U _{C b}), or max(U _{C a­})=min(U _{C c}), min(U _{C a})=max(U _{C c}), or max(U _{C c})=min(U _{C b}), min(U _{C c})=max(U _{C b}), it is achieved the alternate flowing of capacitive energy constitutes the peripheral passage of capacitive energy, and then keeps alternate submodule capacitor voltage stable, is the protection content of this right.

5. according to the centralized half-bridge MMC of auxiliary capacitor based on equality constraint described in right 1 from all pressing topology, it is characterised in that: auxiliary capacitorC ₁、C ₂Both as the passage of A, B capacitive coupling energy exchange, again as the passage of B, C capacitive coupling energy exchange；The function of auxiliary capacitor focus utilization in topology the most all presses the device consumption in subsidiary loop to reduce；Auxiliary capacitorC ₁Function concentrate, auxiliary capacitorC ₂Function do not concentrate；Auxiliary capacitorC ₁Function do not concentrate, auxiliary capacitorC ₂Function concentrate topology in interest field.

6. according to the centralized half-bridge MMC of auxiliary capacitor based on equality constraint described in right 1 from all pressing topology, it is characterized in that: the centralized half-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, not only serve as multi-level voltage source current converter and directly apply to flexible direct-current transmission field, also can be by constituting STATCOM (STATCOM), Research on Unified Power Quality Conditioner (UPQC), the device such as THE UPFC (UPFC) is applied to flexible AC transmission field；Other application scenarios of this utility model topology of indirect utilization and thought are in interest field.