CN109742961A - A kind of heat balance control method of modularization multi-level converter - Google Patents

A kind of heat balance control method of modularization multi-level converter Download PDF

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Publication number
CN109742961A
CN109742961A CN201811458959.4A CN201811458959A CN109742961A CN 109742961 A CN109742961 A CN 109742961A CN 201811458959 A CN201811458959 A CN 201811458959A CN 109742961 A CN109742961 A CN 109742961A
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submodule
temperature
need
value
balance
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邢作霞
王鸿毅
赵盈洁
赵海川
王湘明
张超
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Shenyang University of Technology
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Shenyang University of Technology
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Abstract

A kind of heat balance control method of modularization multi-level converter, the proposition of this method novelty: modular multilevel balances the thermal unbalance problem between submodule using active thermal balance control there are thermal unbalance phenomenon between submodule;(1) active thermal balance proposed using this method is controlled to balance the junction temperature between submodule, and the unbalanced phenomenon of temperature can be improved between submodule;(2) disequilibrium of the Temperature Distribution and junction temperature of corresponding power semiconductor can reduce between submodule, and temperature change number and the number to reach a high temperature can also have opposite improvement.(3) and the junction temperature that can reduce between submodule on the basis of capacitor voltage balance of thermal balance algorithm is poor, the performance without reducing system.(4) this balance method also can reduce the maximum temperature of power semiconductor, so that the service life of power semiconductor be made to increase.

Description

A kind of heat balance control method of modularization multi-level converter
Technical field
The content of present invention is related to a kind of heat balance control method of modularization multi-level converter, solves Electrical transformation The thermal unbalance problem of multilevel converter in device is a kind of heat balance method being embedded in capacitor voltage balance algorithm.
Background technique
Modularization multi-level converter is as a kind of novel multi-level voltage source current converter (voltage-sourced Converter, VSC), since it is highly suitable for direct current transportation occasion, obtain the height of international academic community and industry Concern.Modularization multi-level converter (MMC), by its own, loss is low, harmonic distortion is small, scalability is high, is easy to construct The significant advantages such as multiterminal element network have gradually replaced two level/three-level converter in high-voltage large-capacity flexible direct current field In application.MMC will be balanced the capacitance voltage submodule on bridge arm for stable operation, and not consider in submodule Balance between the loss and junction temperature of power device.In practical applications, in submodule capacitor of different sizes, and capacitance voltage Balanced action in the submodule of low capacitance on-state loss and switching loss it is higher, lead to the semiconductor devices in submodule Temperature also increase, cause the imbalance of temperature between different submodules.The submodule for bearing more to be lost can generate more Temperature, the reduction of the excessively high damage and service life that will cause device of temperature.And temperature repeatedly changes can generate thermal and mechanical stress, meeting Lead to the damage of power device connecting material in submodule, may result in component failure after long-term temperature variation.Both at home and abroad Scholar has been devoted in the heat balance control method research of modular multilevel.
Summary of the invention
Goal of the invention:
The present invention provides a kind of heat balance control method based on modularization multi-level converter, and the purpose is to solve height Peak load operation and the influence in service life of the intermodule temperature imbalance to inverter.What it can be controlled in capacitor voltage balance On the basis of thermal balance between control submodule (Sub-module, SM);Temperature change variation between each submodule is introduced, is protected The temperature difference on the basis of not changing submodule output voltage waveforms and waveform quality between balanced each submodule is demonstrate,proved, submodule is prevented Semiconductor devices in block causes aging or damage due to high temperature or frequent temperature change.It can be achieved between different submodules Thermal stress distribution extends the service life of each submodule.
Technical solution:
A kind of heat balance control method of modularization multi-level converter, it is characterised in that: the proposition of this method novelty: For modular multilevel there are thermal unbalance phenomenon between submodule, the heat balanced between submodule using active thermal balance control is uneven Weighing apparatus problem;The maximum temperature difference allowed between each submodule is being set in heat balance control method, in each group submodule The m of blockiChoose maximum and minimum value m in valuemax、mmin, difference between the two is exactly maximum difference Δ m between group, sets one Maximum difference permissible value mrefTo maintain to balance the equalized temperature between each submodule;This method design submodule allocation flow is worked as mrefWhen less than Δ m, submodule is ranked up according to arm current direction, arm electric current is timing, and submodule is pressed to the size of m value Ascending order arrangement.Work as mrefWhen greater than Δ m, submodule is arranged by the size descending of m value.The allocation flow will be between submodule Temperature in embedded capacitor balance of voltage method by being balanced.Condenser voltage Vcu and device junction temperature T may be implementedj Balance;According to the operation data of modularization multi-level converter in this method, the number for the submodule that need to be connected is calculated, then Determine that the submodule for needing to put into or cut off, the submodule even put into are according to the charge status for having put into submodule Charged state, and when need to put into submodule, then it is the smallest that capacitance voltage, submodule deblocking temperature are chosen in the submodule having not been put to Submodule investment;If the submodule put into is in charged state, and when need to cut out submodule, then in the submodule put into Choose capacitance voltage maximum, the biggish submodule of submodule deblocking temperature is cut out;If the submodule put into is in discharge condition, and needs When putting into submodule, then capacitance voltage maximum is chosen in the submodule having not been put to, the biggish submodule of submodule deblocking temperature is thrown Enter;If the submodule put into is in discharge condition, and when need to cut out submodule, then chooses capacitor in the submodule put into The smallest submodule of voltage is cut out.
Specifically: the power loss equivalence of IGBT and diode is respectively that two current sources export outward by this method Power, and the heat transfer process between PN junction and device outer case then uses thermal resistance Rthc-sTAnd Rthc-sDIt indicates, wherein subscript T is indicated The thermal resistance of IGBT, subscript D indicate the thermal resistance of anti-paralleled diode;Equally, the heat transmitting between device outer case and radiator Process can use thermal resistance Rthc-sTAnd Rthc-sDIt indicating, specific thermal resistance parameter is found from the tables of data that manufacturer provides, it After obtain:
Tj_T=PT(Rthc-sT+RthCH-T)+θ (6)
Tj_D=PD(Rthc-sD+RthCH-D)+θ (7)
Wherein Tj_TIt is expressed as the junction temperature of the part IGBT, Tj_DIndicate the junction temperature of diode section;PTFor the total losses of IGBT, PDFor the total losses of anti-paralleled diode, θ indicates radiator temperature.Specifically, it is assumed that each bridge arm has n submodule, and n is logical Often it is even number, then submodule is divided into n/2 group, every group includes 2 submodules;Meanwhile the number of each group also it is thus determined that Get off, i.e., 1 arrives n/2 group;Submodule capacitor voltage, the temperature of IGBT temperature and anti-paralleled diode are first measured, temperature is by hot-die Type estimation.Then the voltage of two submodules in grouping and temperature are subjected to normalizing calculating.
ai=Vc,i=∑ Vc/ 2 (i=1,2) (8)
mi=ai+bi+ci (11)
Wherein unrestricted choice of the i between submodule;aiFor the average voltage of every group of submodule;biFor the loss of IGBT Heat production temperature superimposition value;ciFor the loss heat production superposition value of anti-paralleled diode;In the m of each group submoduleiChoose in value it is maximum and Minimum value mmax、mmin, difference between the two is exactly maximum difference Δ m between group, need to set a maximum difference permissible value mrefTo tie up Maintain an equal level weighing apparatus, and the submodule number that need to be connected is divided by the radix that the quotient that group number obtains is that each group need to be opened, when being allocated to remainder, It need to be according to Δ m and mrefIt distributes, works as mrefIt does not need to be adjusted the ranking results of submodule when greater than Δ m, it can make It is sequentially allocated with the ranking results of most initial to 1 to n/2 group.Work as mrefWhen less than Δ m, need according to arm current direction to submodule Block is ranked up, and arm electric current is timing, submodule is arranged by the size ascending order of m value, on the contrary then descending arranges.By using institute The solution of proposition, the temperature between submodule in embedded capacitor balance of voltage method by being balanced.Thermal balance Control principle drawing is as shown in Figure 4.It is thereby achieved that condenser voltage VcuWith device junction temperature TjBalance.
Advantageous effect:
The present invention provides a kind of heat balance control method based on modularization multi-level converter, and MMC is due to having output The advantages that level number is high, switching frequency is low, waveform quality is good, therefore have good future in engineering applications and current voltage source The hot spot of type inverter research.This method is between proposing thermal equilibrium control strategy the problem of thermal unbalance MMC submodule, (1) The active thermal balance proposed using this method is controlled to balance the junction temperature between submodule, and temperature is unbalanced between submodule Phenomenon can be improved;(2) disequilibrium of the Temperature Distribution and junction temperature of corresponding power semiconductor can be between submodule It reduces, temperature change number and the number to reach a high temperature can also have opposite improvement.(3) and thermal balance algorithm can be in capacitor The junction temperature reduced between submodule on the basis of the balance of voltage is poor, the performance without reducing system.(4) this balance method also can The maximum temperature for enough reducing power semiconductor, so that the service life of power semiconductor be made to increase.
Detailed description of the invention
Fig. 1: MMC Basic Topological
Fig. 2: the thermal model of power device in half-bridge Neutron module
Fig. 3: thermal equilibrium control flow chart
Fig. 4: the schematic diagram of thermal equilibrium control
Specific embodiment:
1) model analysis of MMC
Three-phase MMC system is made of three phase bridge arms, and each phase bridge arm is made of upper half bridge arm and lower half bridge arm two parts, Each half bridge arm is respectively by N number of submodule and bridge arm inductance LaIt is sequentially connected in series, the output end of each phase bridge arm is from two bridge arms The tie point of inductance is drawn.The concatenated number of its submodule is by the logical of the rated power of converter, voltage class and switching device Stream ability and compressive resistance determine.The three-phase topological structure of typical N+1 level is as shown in Figure 1.Inverter is by 3 phase element groups At every mutually upper and lower bridge arm has N number of submodule cooperation switching, and any time keeps while the submodule sum of investment is N, can Maintain DC voltage UdcIt is constant.
2) loss assessment
The power loss of IGBT is mainly damaged by on-state loss, cut-off loss, switching loss and driving in the calculating of loss Four parts composition is consumed, because the ratio that cut-off loss and drive loss account for total losses is minimum, the temperature of generation influences to ignore.Institute Only to calculate the on-state loss and switching loss of IGBT.In the loss calculation of anti-paralleled diode, only to on-state loss and instead Calculating is overlapped to loss is restored.
In order to estimate device junction temperature used in thermal equilibrium control strategy, need to calculate power loss.For half-bridge SM, function Rate loss can be simply divided into two parts: on-state loss and switching loss (or reverse recovery loss of diode).IGBT and The forward conduction voltage of diode is mainly related with conducting electric current and junction temperature, calculates the on-state loss in a complete power frequency period It needs to integrate its voltage and current product.The on-state loss of IGBT and diode are as follows:
Wherein, Pcon,VTAnd Pcon,VDFor the on-state loss of IGBT and diode, t is time, θjJunction temperature is represented, unit is ℃;TcFor a complete power frequency period, UVTCollection penetrates the voltage between grade, i when being connected for IGBTVTFor IGBT collector current;UVD For diode forward pressure drop, iVDFor diode forward average current.
The switching loss of IGBT and the reverse recovery loss of diode are calculated, it is available according to adding up for on-off times The corresponding switching loss of IGBT asks its mean value to can be obtained the average switch loss power of each submodule the time, similarly Diode reverse recovery losses can be obtained, calculating process is as follows:
Wherein, Pon,T、Poff,TAnd Prec,DRespectively represent the turn-on consumption and turn-off power loss and anti-paralleled diode of IGBT Reverse recovery loss, unit W;t0For the initial time of computed losses;tα、tβ、tγRespectively indicate opening, turning off for IGBT Moment and the Reverse recovery moment of diode;UCE,onIndicate the blocking voltage before IGBT is opened;UCE,offAfter indicating IGBT shutdown Blocking voltage, unit V;UF,refBlocking voltage after indicating diode reverse recovery, unit V;UCE,refFor manufacturer institute The reference voltage base value calculated in switching loss between collector and emitter, unit V are provided.
3) junction temperature is fed back
In order to observe the Temperature Distribution and hot property of power device in submodule, need to survey the temperature of IGBT device Amount, and the junction temperature inside power device can not directly measure to obtain, it is therefore desirable to it is utilized by establishing thermal model to power device Spreader surface temperature estimates its junction temperature.Therefore equivalent heater circuit model as shown in Figure 2 is established.Respectively by IGBT and two poles The power loss equivalence of pipe is that two current sources carry out outside output power, and the heat transfer process between PN junction and device outer case is then With thermal resistance Rthc-sTAnd Rthc-sDIt indicates, wherein subscript T indicates that the thermal resistance of IGBT, subscript D indicate the heat of anti-paralleled diode Resistance.Equally, the heat transfer process between device outer case and radiator can use thermal resistance Rthc-sTAnd Rthc-sDIt indicates, specifically Thermal resistance parameter can be found from the tables of data that manufacturer provides.By Fig. 2 it follows that
Tj_T=PT(Rthc-sT+RthCH-T)+θ (6)
Tj_D=PD(Rthc-sD+RthCH-D)+θ (7)
Wherein Tj_TIt is expressed as the junction temperature of the part IGBT, Tj_DIndicate the junction temperature of diode section;PTFor the total losses of IGBT, PDFor the total losses of anti-paralleled diode, θ indicates radiator temperature.
Specifically, it is assumed that each bridge arm has n submodule (n is usually even number), then submodule is divided into n/2 Group, every group includes 2 submodules.Meanwhile the number of each group also it is thus determined that getting off, i.e., 1 arrives n/2 group.First measurement submodule electricity Hold the temperature of voltage, IGBT temperature and anti-paralleled diode, temperature is estimated by thermal model.Then by two submodules in grouping Voltage and temperature carry out normalizing calculating.
ai=Vc,i=∑ Vc/ 2 (i=1,2) (8)
mi=ai+bi+ci (11)
Wherein unrestricted choice of the i between submodule;aiFor the average voltage of every group of submodule;biFor the loss of IGBT Heat production temperature superimposition value;ciFor the loss heat production superposition value of anti-paralleled diode;As described in the flow chart of figure 3, in each group submodule MiChoose maximum and minimum value m in valuemax、mmin, difference between the two is exactly maximum difference Δ m between group, need to set one most Big difference permissible value mrefIt maintains to balance, the submodule number that need to be connected is divided by the base that the quotient that group number obtains is that each group need to be opened Number, need to be according to Δ m and m when being allocated to remainderrefIt distributes, works as mrefThe sequence knot to submodule is not needed when greater than Δ m Fruit is adjusted, it can is sequentially allocated using the ranking results of most initial to 1 to n/2 group.Work as mrefWhen less than Δ m, root is needed Submodule is ranked up according to arm current direction, arm electric current be timing, by submodule by m value size ascending order arrange, it is on the contrary then Descending arrangement.By using the solution proposed, the temperature between submodule passes through in embedded capacitor balance of voltage method To be balanced.Thermal equilibrium control schematic diagram is as shown in Figure 4.It is thereby achieved that condenser voltage VcuWith device junction temperature Tj Balance.
In summary:
The inverter voltage and current value that the present invention is provided by supplier, obtains semiconductor devices under real work junction temperature Loss, calculating analysis is carried out to the loss of submodule each in modularization multi-level converter;Pass through half-bridge Neutron module heat Model improves existing heat balance control method;It is proposed that thermal equilibrium control is calculated on the basis of capacitor voltage balance algorithm Method introduces weight factor, by a certain number of submodules in the temperature for considering capacitance voltage, IGBT temperature and anti-paralleled diode Influence factor under carry out ordered arrangement.The running temperature that each submodule can be effectively reduced increases the maximum operation of MMC Power.

Claims (2)

1. a kind of heat balance control method of modularization multi-level converter, it is characterised in that: this method utilizes active thermal balance Control is to balance the thermal unbalance problem between submodule;Allow between each submodule being set in heat balance control method Maximum temperature difference, in the m of each group submoduleiChoose maximum and minimum value m in valuemax、mmin, difference between the two is exactly group Between maximum difference Δ m, set a maximum difference permissible value mrefTo maintain to balance the equalized temperature between each submodule;It should Method design submodule allocation flow works as mrefWhen less than Δ m, submodule is ranked up according to arm current direction, arm electric current is Timing is arranged submodule by the size ascending order of m value;Work as mrefWhen greater than Δ m, submodule is arranged by the size descending of m value; The allocation flow is by the temperature between submodule by being balanced in embedded capacitor balance of voltage method;Realize capacitor Voltage VcuWith device junction temperature TjBalance;According to the operation data of modular multilevel in this method, the submodule that need to be connected is calculated Then the number of block determines the submodule for needing to put into or cut off according to the charge status for having put into submodule, has even thrown The submodule entered is in charged state, and when need to put into submodule, then capacitance voltage, son are chosen in the submodule having not been put to The smallest submodule investment of module temperature;If the submodule put into is in charged state, and when need to cut out submodule, then Capacitance voltage maximum is chosen in the submodule of investment, the biggish submodule of submodule deblocking temperature is cut out;If at the submodule put into In discharge condition, and when need to put into submodule, then choose that capacitance voltage is maximum, submodule deblocking temperature in the submodule having not been put to Biggish submodule investment;If the submodule put into is in discharge condition, and when need to cut out submodule, then in the son put into The smallest submodule of capacitance voltage is chosen in module to cut out.
2. a kind of heat balance control method of modularization multi-level converter according to claim 1, it is characterised in that: should The power loss equivalence of IGBT and diode is respectively the next outside output power of two current sources by method, and outside PN junction and device Heat transfer process between shell then uses thermal resistance Rthc-sTAnd Rthc-sDIt indicates, wherein subscript T indicates the thermal resistance of IGBT, subscript D Indicate the thermal resistance of anti-paralleled diode;Equally, the thermal resistance R of the heat transfer process between device outer case and radiatorthc-sTWith Rthc-sDIt indicates, specific thermal resistance parameter is found from the tables of data that manufacturer provides, obtained later:
Tj_T=PT(Rthc-sT+RthCH-T)+θ (1)
Tj_D=PD(Rthc-sD+RthCH-D)+θ (2)
Wherein Tj_TIt is expressed as the junction temperature of the part IGBT, Tj_DIndicate the junction temperature of diode section;PTFor the total losses of IGBT, PDFor The total losses of anti-paralleled diode, θ indicate radiator temperature.Specifically, it is assumed that each bridge arm has n submodule, and n is usually Submodule is then divided into n/2 group by even number, and every group includes 2 submodules;Meanwhile the number of each group is also it is thus determined that get off, I.e. 1 arrives n/2 group;Submodule capacitor voltage, the temperature of IGBT temperature and anti-paralleled diode are first measured, temperature is estimated by thermal model Meter;Then the voltage of two submodules in grouping and temperature are subjected to normalizing calculating;
mi=ai+bi+ci (6)
Wherein unrestricted choice of the i between submodule;aiFor the average voltage of every group of submodule;biFor the loss heat production of IGBT Temperature superimposition value;ciFor the loss heat production superposition value of anti-paralleled diode;In the m of each group submoduleiChoose in value minimum and maximum Value mmax、mmin, difference between the two is exactly maximum difference Δ m between group, need to set a maximum difference permissible value mrefTo remain flat Weighing apparatus, the submodule number that need to be connected when being allocated to remainder, need root divided by the radix that the quotient that group number obtains is that each group need to be opened According to Δ m and mrefIt distributes, works as mrefIt does not need to be adjusted the ranking results of submodule when greater than Δ m, that is, uses most initial Ranking results be sequentially allocated to 1 to n/2 group;Work as mrefWhen less than Δ m, need to arrange submodule according to arm current direction Sequence, arm electric current are timing, submodule are arranged by the size ascending order of m value, on the contrary then descending arranges.
CN201811458959.4A 2018-11-30 2018-11-30 A kind of heat balance control method of modularization multi-level converter Pending CN109742961A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110635683A (en) * 2019-09-06 2019-12-31 上海交通大学 Two-port sub-module, self-coupling type direct current transformer and modulation method thereof
CN111917316A (en) * 2020-06-04 2020-11-10 东南大学 Submodule temperature adjusting and balancing method based on centralized control of modular multilevel converter
CN112152495A (en) * 2019-06-28 2020-12-29 新疆金风科技股份有限公司 Control method and controller of modular multilevel converter
CN112803792A (en) * 2021-02-01 2021-05-14 中南大学 Traction converter thermal field control method and system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018006970A1 (en) * 2016-07-07 2018-01-11 Abb Schweiz Ag Semiconductor power stack of a modular multilevel converter
CN108155814A (en) * 2018-01-05 2018-06-12 湖南大学 MMC converter valves pressure equalizing control method based on temperature

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018006970A1 (en) * 2016-07-07 2018-01-11 Abb Schweiz Ag Semiconductor power stack of a modular multilevel converter
CN108155814A (en) * 2018-01-05 2018-06-12 湖南大学 MMC converter valves pressure equalizing control method based on temperature

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
FREDERIK HAHN等: "Thermal Analysis and Balancing for Modular Multilevel Converters in HVDC Applications", 《IEEE TRANSACTIONS ON POWER ELECTRONICS》 *
屠卿瑞等: "基于结温反馈方法的模块化多电平换流器型高压直流输电阀损耗评估", 《高电压技术》 *
彭茂兰: "MMC电容电压平衡优化算法研究", 《中国优秀硕士学位论文全文数据库工程科技Ⅱ辑》 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112152495A (en) * 2019-06-28 2020-12-29 新疆金风科技股份有限公司 Control method and controller of modular multilevel converter
CN110635683A (en) * 2019-09-06 2019-12-31 上海交通大学 Two-port sub-module, self-coupling type direct current transformer and modulation method thereof
CN110635683B (en) * 2019-09-06 2021-05-11 上海交通大学 Two-port sub-module, self-coupling type direct current transformer and modulation method thereof
CN111917316A (en) * 2020-06-04 2020-11-10 东南大学 Submodule temperature adjusting and balancing method based on centralized control of modular multilevel converter
CN112803792A (en) * 2021-02-01 2021-05-14 中南大学 Traction converter thermal field control method and system

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