CN205725504U - The centralized full-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology - Google Patents

Abstract

This utility model provides the centralized full-bridge MMC of auxiliary capacitor based on equality constraint from all pressing topology.Full-bridge MMC is from all pressing topology, by full-bridge MMC model with from all pressure subsidiary loop joint mappings.Full-bridge MMC model and 6 in all pressure subsidiary loop is by subsidiary loopNIndividual IGBT module generation electrical link, IGBT module triggers, and both constitute the centralized full-bridge MMC of auxiliary capacitor based on equality constraint from all pressing topology；IGBT module locking, topoligical equivalence is full-bridge MMC topology.This full-bridge MMC is from all pressing topology, DC side fault can be clamped, do not rely on special Pressure and Control simultaneously, can be on the basis of completing the conversion of alternating current-direct current 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 full-bridge MMC.

Description

The centralized full-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology

Technical field

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

Background technology

Modularization multi-level converter MMC is the developing direction of following HVDC Transmission Technology, and MMC uses submodule (Sub- Module, SM) mode that cascades constructs converter valve, it is to avoid the directly series connection of big metering device, reduce device conforming Requirement, simultaneously facilitates dilatation and redundant configuration.Along with the rising of level number, output waveform, close to sinusoidal, can effectively avoid low electricity The defect of flat VSC-HVDC.

Full-bridge MMC is combined by full-bridge submodule, full-bridge submodule by four IGBT module, a sub-module capacitance and 1 mechanical switch is constituted, and flexible operation has DC Line Fault clamping ability.

Different from two level, three level VSC, the DC voltage of full-bridge MMC is not supported by a bulky capacitor, but by A series of separate suspension submodule capacitances in series support.In order to ensure waveform quality and the guarantee that AC voltage exports In module, each power semiconductor bears identical stress, also for preferably supporting DC voltage, reduces alternate circulation, must Must ensure that 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 equilibrium of full-bridge MMC Neutron module capacitance voltage at present to ask The main flow thinking of topic.But, the realization of ranking function has to rely on the Millisecond sampling of capacitance voltage, needs substantial amounts of sensor And optical-fibre channel is coordinated；Secondly, when group number of modules increases, the operand of capacitance voltage sequence increases rapidly, for The hardware designs of controller brings huge challenge；Additionally, submodule is cut-off frequency and has the highest by sequence all realizations of pressure algorithm Requirement, cut-off frequency with all pressure effect be closely related, 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 one Plant the thinking relying on clamp diode and transformator to realize the equilibrium of MMC submodule capacitor voltage.But the program in design Determining degree and destroy the modular nature of submodule, submodule capacitive energy interchange channel is also confined in mutually, could not be fully sharp With the existing structure of MMC, introducing of three transformators also brings along bigger being transformed into while making control strategy complicate This.

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 calculation Method, can reduce submodule simultaneously accordingly and trigger frequency and capacitor's capacity and have the full-bridge MMC of DC Line Fault clamping ability from all Pressure topology.

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

The centralized full-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, complete including be made up of A, B, C three-phase Bridge MMC model, each brachium pontis of A, B, C three-phase respectively byNIndividual full-bridge submodule and 1 brachium pontis reactor are in series；Including by 6NIndividual IGBT module, 6N+ 5 clamp diodes, 2 auxiliary capacitors, assisting back from all pressures of 2 auxiliary IGBT module compositions Road.

The above-mentioned centralized full-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, in full-bridge MMC model, in A phase 1st submodule of brachium pontis, one IGBT module midpoint is upwards connected with dc bus positive pole, in another IGBT module Point is connected with one IGBT module midpoint of the 2nd submodule of brachium pontis in A phase downwards；In A phase the of brachium pontisiIndividual submodule, WhereiniValue be 2～N-1, one IGBT module midpoint is upwards with in A phase the of brachium pontisiOne IGBT of-1 submodule Module midpoint is connected, and another IGBT module midpoint is downwards with in A phase the of brachium pontisiOne IGBT module midpoint of+1 submodule It is connected；In A phase the of brachium pontisNIndividual submodule, one IGBT module midpoint is down through the lower brachium pontis of two brachium pontis reactors and A phase One IGBT module midpoint of the 1st submodule be connected, another IGBT module midpoint is upwards with in A phase the of brachium pontisN-1 One IGBT module midpoint of individual submodule is connected；The of the lower brachium pontis of A phaseiIndividual submodule, whereiniValue be 2～N-1, its The of one IGBT module midpoint upwards brachium pontis lower with A phaseiOne IGBT module midpoint of-1 submodule is connected, another IGBT Module midpoint downwards with the of A phase time brachium pontisiOne IGBT module midpoint of+1 submodule is connected；The of the lower brachium pontis of A phaseNHeight Module, one IGBT module midpoint is connected with dc bus negative pole downwards, another IGBT module midpoint upwards with under A phase The of brachium pontisNTwo IGBT module midpoints of-1 submodule are connected.B phase and the connected mode of C phase upper and lower bridge arm submodule and A Consistent.

The above-mentioned centralized full-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, in all pressure subsidiary loops, the One auxiliary capacitor positive pole connects auxiliary IGBT module, and negative pole connects clamp diode and is incorporated to dc bus positive pole；Second auxiliary Helping electric capacity negative pole to connect auxiliary IGBT module, positive pole connects clamp diode and is incorporated to dc bus negative pole.Clamp diode, passes through IGBT module connects the 1st sub-module capacitance and first auxiliary capacitor positive pole in the upper brachium pontis of A phase；A is connected by IGBT module Go up in brachium pontis mutuallyiIndividual sub-module capacitance and thei+ 1 sub-module capacitance positive pole, whereiniValue be 1～N-1；Pass through IGBT Module connects in A phase in brachium pontis theNIndividual sub-module capacitance brachium pontis 1st sub-module capacitance positive pole lower with A phase；Pass through IGBT module Connect in the lower brachium pontis of A phase theiThe lower brachium pontis of individual sub-module capacitance and A phase thei+ 1 sub-module capacitance positive pole, whereiniValue be 1 ~N-1；The is connected in the lower brachium pontis of A phase by IGBT moduleNIndividual sub-module capacitance and second auxiliary capacitor positive pole.Clamper two pole Pipe, by the 1st sub-module capacitance and first auxiliary capacitor negative pole in brachium pontis in IGBT module connection B phase；By IGBT mould Block connects in B phase in brachium pontis theiIndividual 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 IGBT moduleNIndividual sub-module capacitance brachium pontis 1st sub-module capacitance negative pole lower with B phase；Pass through IGBT module connects in the lower brachium pontis of B phase theiThe lower brachium pontis of individual sub-module capacitance and B phase thei+ 1 sub-module capacitance negative pole, whereini Value be 1～N-1；The is connected in the lower brachium pontis of B phase by IGBT moduleNIndividual sub-module capacitance is born with second auxiliary capacitor Pole.In C phase, the annexation of clamp diode is similar to A phase or B phase.

Accompanying drawing explanation

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

Fig. 2 is that the centralized full-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, below in conjunction with accompanying drawing to the composition to utility model Mode is specifically described with operation principle.But full-bridge MMC based on this principle is not limited to Fig. 2 from all pressure topologys.

With reference to Fig. 2, the centralized full-bridge MMC of auxiliary capacitor based on equality constraint from all pressing topology, including by A, B, C three-phase Constitute full-bridge MMC model, each brachium pontis of A, B, C three-phase respectively byNIndividual full-bridge submodule and the series connection of 1 brachium pontis reactor and Become, including by 6NIndividual IGBT module, 6N+ 5 clamp diodes, 2 auxiliary capacitors, 2 assist the most equal of IGBT module composition Pressure subsidiary loop.

In full-bridge MMC model, the 1st submodule of brachium pontis in A phase, one IGBT module midpoint upwards with dc bus Positive pole is connected, and another IGBT module midpoint is connected with one IGBT module midpoint of the 2nd submodule of brachium pontis in A phase downwards Connect；In A phase the of brachium pontisiIndividual submodule, whereiniValue be 2 ~N-1, one IGBT module midpoint upwards with bridge in A phase The of armiOne IGBT module midpoint of-1 submodule is connected, and another IGBT module midpoint is downwards with in A phase the of brachium pontisiOne IGBT module midpoint of+1 submodule is connected；In A phase the of brachium pontisNIndividual submodule, one IGBT module midpoint to Upper with in A phase the of brachium pontisNOne IGBT module midpoint of-1 submodule is connected, and another IGBT module midpoint is down through two Individual brachium pontis reactorL ₀One IGBT module midpoint of the 1st full-bridge submodule of brachium pontis lower with A phase is connected；The lower brachium pontis of A phase TheiIndividual submodule, whereiniValue be 2 ~N-1, the of one IGBT module midpoint upwards brachium pontis lower with A phasei-1 submodule One IGBT module midpoint of block is connected, another IGBT module midpoint downwards with the of A phase time brachium pontisi+ 1 submodule one IGBT module midpoint is connected；The of the lower brachium pontis of A phaseNIndividual submodule, one IGBT module midpoint is born with dc bus downwards Pole is connected, the of another IGBT module midpoint upwards brachium pontis lower with A phaseNOne IGBT module midpoint of-1 submodule is connected Connect.The connected mode of B phase and 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 also Enter 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 IGBT moduleT _{au_1}1st sub-module capacitance in brachium pontis in connection A phaseC _{­au­_1}With auxiliary capacitorC ₁Positive pole；Pass through IGBT moduleT _{au_i} 、T _{au_i+1}Connect in A phase in brachium pontis theiIndividual sub-module capacitanceC _{­au­_i} Withi+ 1 submodule Block electric capacityC­_{au­_i+1}Positive pole, whereiniValue be 1～N-1；Pass through IGBT moduleT _{au_N} 、T _{al_1}Connect in A phase in brachium pontis theN Individual sub-module capacitanceC­_{au­_N} Brachium pontis 1st sub-module capacitance lower with A phaseC­_{al­_1}Positive pole；By IGBT module T_{al_i} 、T _{al_i+1}Even Connect under A phase in brachium pontisiIndividual 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 IGBT moduleT _{al_N} Connect in the lower brachium pontis of A phase theNIndividual sub-module capacitanceC _{­al_N} With auxiliary capacitorC ₂Positive pole.Clamp diode, passes through IGBT moduleT _{bu_1}1st sub-module capacitance in brachium pontis in connection B phaseC­_{bu­_1}With auxiliary electricity HoldC ₁Negative pole；Pass through IGBT moduleT _{bu_i} 、T _{bu_i+1}Connect in B phase in brachium pontis theiIndividual sub-module capacitanceC­_{bu­_i} Withi+ 1 son Module capacitanceC _{­bu­_i+1}Negative pole, whereiniValue be 1～N-1；Pass through IGBT moduleT _{bu_N} 、T _{bl_1}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 IGBT moduleT _{bl_i} 、T _{bl_i+1} 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, its IniValue be 1～N-1；Pass through IGBT moduleT _{bl_N} Connect in the lower brachium pontis of B phase theNIndividual sub-module capacitanceC­ _{bl­_N} With auxiliary electricity HoldC ₂Negative pole.In C phase, the annexation of clamp diode is consistent with A.

Under normal circumstances, from the most all pressure subsidiary loop in 6NIndividual IGBT moduleT _{au_i} 、T _{al_i} 、T _{bu_i}、T _{bl_i} 、T _{cu_i} 、T _{cl_i} Often Close, whereiniValue be 1～N, first sub-module capacitance of brachium pontis in A phaseC _{au_1}During bypass, now assist IGBT moduleT ₁Disconnected Open, submodule electric capacityC _{au_1}With auxiliary capacitorC ₁In parallel by clamp diode；Brachium pontis in A phaseiIndividual sub-module capacitanceC _{au_i} Other Lu Shi, whereiniValue be 2～N, submodule electric capacityC _{au_i} With submodule electric capacityC _{au_i-1}In parallel by clamp diode；A phase First sub-module capacitance of lower brachium pontisC _{al_1}During bypass, submodule electric capacityC _{al_1}By clamp diode, two brachium pontis reactorsL ₀ With 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 Block electric capacityC _{al­_i} With submodule electric capacityC _{al_i-1}In parallel by clamp diode；Auxiliary IGBT moduleT ₂During Guan Bi, auxiliary capacitorC ₂ By clamp diode and submodule electric capacityC _{al_N} In parallel.

Under normal circumstances, from the most all pressure subsidiary loop in 6NIndividual IGBT moduleT _{au_i} 、T _{al_i} 、T _{bu_i}、T _{bl_i} 、T _{cu_i} 、T _{cl_i} Often Close, whereiniValue be 1～N, assist IGBT moduleT ₁During Guan Bi, auxiliary capacitorC ₁With submodule electric capacityC _{bu_1}By clamper two Pole pipe is in parallel；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 submodule Block electric capacityC _{bl_i} During bypass, whereiniValue be 1～N-1, submodule electric capacityC _{bl_i} With submodule electric capacityC _{bl_i+1}By clamper two Pole pipe is in parallel；The lower brachium pontis of B phase theNIndividual sub-module capacitanceC _{bl_N} During bypass, submodule electric capacityC _{bl_N} With auxiliary capacitorC ₂Pass through clamper Diodes in parallel.Above-mentioned auxiliary IGBT moduleT ₁Trigger " patrolling of first submodule triggering signal of signal and brachium pontis in A, C phase Volume with " 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 ₂Alternately Guan Bi, shutoff, 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 full-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 full-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 realities Execute example.Based on the embodiment in the application, those of ordinary skill in the art are obtained under not making creative work premise Every other embodiment, broadly fall into the application protection scope.

Claims (4)

1. the centralized full-bridge MMC of auxiliary capacitor based on equality constraint is from all pressing topology, it is characterised in that: include by A, B, C tri- The full-bridge MMC model constituted mutually, each brachium pontis of A, B, C three-phase respectively byNIndividual full-bridge submodule and the series connection of 1 brachium pontis reactor and Become；Including by 6NIndividual IGBT module, 6N+ 5 clamp diodes, 2 auxiliary capacitorsC ₁、C ₂, 2 auxiliary IGBT moduleT ₁、T ₂Structure Become the most all presses subsidiary loop.

2. according to the centralized full-bridge MMC of auxiliary capacitor based on equality constraint described in right 1 from all pressing topology, its feature to exist In: in full-bridge MMC model, the 1st submodule of brachium pontis in A phase, one IGBT module midpoint upwards with dc bus positive pole Being connected, another IGBT module midpoint is connected with one IGBT module midpoint of the 2nd submodule of brachium pontis in A phase downwards；A Go up the of brachium pontis mutuallyiIndividual submodule, whereiniValue be 2 ~N-1, one IGBT module midpoint upwards with brachium pontis in A phase TheiOne IGBT module midpoint of-1 submodule is connected, and another IGBT module midpoint is downwards with in A phase the of brachium pontisi+1 One IGBT module midpoint of individual submodule is connected；In A phase the of brachium pontisNIndividual submodule, one IGBT module midpoint is upwards With in A phase the of brachium pontisNOne IGBT module midpoint of-1 submodule is connected, and another IGBT module midpoint is down through two Brachium pontis reactorL ₀One IGBT module midpoint of the 1st full-bridge submodule of brachium pontis lower with A phase is connected；The of the lower brachium pontis of A phasei Individual submodule, whereiniValue be 2 ~N-1, the of one IGBT module midpoint upwards brachium pontis lower with A phasei-1 submodule One IGBT module midpoint is connected, another IGBT module midpoint downwards with the of A phase time brachium pontisi+ 1 submodule one IGBT module midpoint is connected；The of the lower brachium pontis of A phaseNIndividual submodule, one IGBT module midpoint is born with dc bus downwards Pole is connected, the of another IGBT module midpoint upwards brachium pontis lower with A phaseNOne IGBT module midpoint of-1 submodule is connected Connect；The connected mode of B phase and C phase upper and lower bridge arm submodule is consistent with A；At A, B, C phase upper and lower bridge armiIndividual submodule Mechanical switch it is parallel with respectively up and down between output leadK _{au_i} ,K _{al_i} ,K _{bu_i} ,K _{bl_i} ,K _{cu_i} ,K _{cl_i} , whereiniValue be 1 ~N； A, B, C three-phase status that above-mentioned annexation is constituted is consistent.

3. according to the centralized full-bridge MMC of auxiliary capacitor based on equality constraint described in right 1 from all pressing topology, its feature to exist In: in all pressure subsidiary loops, auxiliary capacitorC ₁Positive pole connects auxiliary IGBT moduleT ₁, negative pole connects clamp diode and is incorporated to directly Stream bus positive pole；Auxiliary capacitorC ₂Negative pole connects auxiliary IGBT moduleT ₂, positive pole connection clamp diode is incorporated to dc bus and bears Pole；Clamp diode, passes through IGBT moduleT _{au_1}1st sub-module capacitance in brachium pontis in connection A phaseC _{au_1}With auxiliary capacitorC ₁Just Pole；Pass through IGBT moduleT _{au_i} 、T _{Au_(i+ 1)}Connect in A phase in brachium pontis theiIndividual sub-module capacitanceC _{au_i} Withi+ 1 submodule electricity HoldC _{au_i+1}Positive pole, whereiniValue be 1～N-1；Pass through IGBT moduleT _{au_N} 、T _{al_1}Connect in A phase in brachium pontis theNIndividual submodule Block electric capacityC _{au_N} Brachium pontis 1st sub-module capacitance lower with A phaseC _{al_1}Positive pole；Pass through IGBT moduleT _{al_i} 、T _{Al_(i+ 1)}Connect under A phase In brachium pontisiIndividual sub-module capacitanceC _{al_i} Withi+ 1 sub-module capacitanceC _{al_i+1}Positive pole, whereiniValue be 1～N-1； Pass through IGBT moduleT _{al_N} Connect in the lower brachium pontis of A phase theNIndividual sub-module capacitanceC _{al_N} With auxiliary capacitorC ₂Positive pole；Clamp diode, Pass through IGBT moduleT _{bu_1}1st sub-module capacitance in brachium pontis in connection B phaseC _{bu_1}With auxiliary capacitorC ₁Negative pole；By IGBT mould BlockT _{bu_i} 、T _{Bu_(i+ 1)}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 IGBT moduleT _{bu_N} 、T _{bl_1}Connect in B phase in brachium pontis theNIndividual sub-module capacitanceC _{bu_N} With B Descend the 1st sub-module capacitance in brachium pontis mutuallyC _{bl_1}Negative pole；Pass through IGBT moduleT _{bl_i} 、T _{Bl_(i+ 1)}Connect in the lower brachium pontis of B phase theiIndividual Submodule electric capacityC _{bl_i} Withi+ 1 sub-module capacitanceC _{bl_i+1}Negative pole, whereiniValue be 1～N-1；Pass through IGBT moduleT _{bl_N} Connect in the lower brachium pontis of B phase theNIndividual sub-module capacitanceC _{bl_N} With auxiliary capacitorC ₂Negative pole；In C phase, the connection of clamp diode is closed It is consistent with A phase or B；In above-mentioned A, B, C three-phase 6NIndividual IGBT moduleT _{au_i} 、T _{al_i} 、T _{bu_i} 、T _{bl_i} 、T _{cu_i} 、T _{cl_i} , whereini Value be 1～N, 6N+ 5 clamp diodes, 2 auxiliary capacitorsC ₁、C ₂And 2 auxiliary IGBT moduleT ₁、T ₂, collectively form From all pressing subsidiary loop.

4. according to the centralized full-bridge MMC of auxiliary capacitor based on equality constraint described in right 1 from all pressing topology, its feature to exist In: during normal condition, from the most all pressure subsidiary loop in 6NIndividual IGBT moduleT _{au_i} 、T _{al_i} 、T _{bu_i} 、T _{bl_i} 、T _{cu_i} 、T _{cl_i} Normally closed, therefore During barrier situation, 6NIndividual IGBT moduleT _{au_i} 、T _{al_i} 、T _{bu_i} 、T _{bl_i} 、T _{cu_i} 、T _{cl_i} Disconnect, whereiniValue be 1～N；Positive reason Under condition, 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 submodule of brachium pontis of A phase Block electric capacityC _{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 Block electric capacityC _{al_i-1}In parallel by clamp diode；Auxiliary IGBT moduleT ₂During Guan Bi, auxiliary capacitorC ₂By clamp diode with Submodule electric capacityC _{al_N} In parallel；Auxiliary IGBT moduleT ₁During Guan Bi, auxiliary capacitorC ₁With submodule electric capacityC _{bu_1}By clamper two pole Pipe is in parallel；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 electricity HoldC _{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 submodule Electric capacityC _{bl_i} During bypass, whereiniValue be 1～N-1, submodule electric capacityC _{bl_i} With submodule electric capacityC _{bl_i+1}By clamper two pole Pipe is in parallel；The lower brachium pontis of B phase theNIndividual sub-module capacitanceC _{bl_N} During bypass, submodule electric capacityC _{bl_N} With auxiliary capacitorC ₂By clamper two Pole pipe is in parallel；Wherein assist IGBT moduleT ₁" the logic triggering first submodule triggering signal of signal and brachium pontis in A, C phase With " consistent；Auxiliary IGBT moduleT ₂The lower brachium pontis of triggering signal and B phase theNThe triggering signal of individual submodule is consistent；At orthogonal stream During energy conversion, each submodule alternately puts into, bypass, assists IGBT moduleT ₁、T ₂It is alternately closed, turns off, in A phase Lower brachium pontis submodule capacitor voltage, under the effect of clamp diode, meets lower column constraint,U _C1≥U _{Cau_1}≥U _{Cau_2}…≥U _{Cau_N} ≥U _{Cal_1}≥U _{Cal_2}…≥U _{Cal_N} ≥U _C2；B phase upper and lower bridge arm submodule capacitor voltage, under the effect of clamp diode, meets Lower column constraint,U _C1≤U _{Cbu_1}≤U _{Cbu_2}…≤U _{Cbu_N} ≤U _{Cbl_1}≤U _{Cbl_2}…≤U _{Cbl_N} ≤U _C2；Auxiliary based on equality constraint Electric capacity centralized full-bridge MMC is from all pressing topology, in dynamic process, and auxiliary capacitorC ₁Both can 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 B The electric capacity that phase voltage is the highest；Against two equality constraints, max(U _Ca)=min(U _Cb), min(U _Ca)=max(U _Cb), in A, B phase In lower brachium pontis 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 is in self-balancing state, and A, B are alternate possesses submodule capacitor voltage from the ability of equalization for topology；If the composition of C phase in topology Form is consistent with A, then the constraints of C, B capacitive coupling voltage is consistent with capacitance voltage constraints between A, B；If it is topological The form of the composition of middle C phase is consistent with B, then capacitance voltage constraints between constraints and A, B of A, C capacitive coupling voltage Unanimously, topology possesses submodule capacitor voltage from the ability of equalization.