CN115549439B - MMC switching loss optimization method and equipment under low-power operation - Google Patents

MMC switching loss optimization method and equipment under low-power operation Download PDF

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CN115549439B
CN115549439B CN202211505284.0A CN202211505284A CN115549439B CN 115549439 B CN115549439 B CN 115549439B CN 202211505284 A CN202211505284 A CN 202211505284A CN 115549439 B CN115549439 B CN 115549439B
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bridge arm
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submodule
current
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CN115549439A (en
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邓富金
王梦悦
李怀龙
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Southeast University
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0048—Circuits or arrangements for reducing losses
    • H02M1/0054—Transistor switching losses
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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Abstract

The invention discloses an MMC switching loss optimization method and equipment under low-power operation, wherein the method comprises the following steps: based on a current model of an alternating current side of the modularized multi-level converter, sampling a submodule switching signal and bridge arm current when the modularized multi-level converter operates at a low power level, and calculating the capacitance voltage variation quantity and the capacitance voltage fluctuation rate of each submodule in a fundamental frequency period; because the modularized multi-level converter operates at a low power level, bridge arm current is smaller, and capacitance voltage fluctuation of the submodule is smaller. If the capacitance voltage fluctuation of the submodule cannot influence the normal operation of the MMC system, the capacitance voltage control period can be reduced, so that the aims of reducing the average switching times and switching loss of the submodule are fulfilled. The invention reduces the loss without increasing the construction cost of the modularized multi-level converter and does not affect the output power quality of the modularized multi-level converter.

Description

MMC switching loss optimization method and equipment under low-power operation
Technical Field
The invention belongs to the technical field of control and regulation of power electronic converters, and particularly relates to a method for optimizing switching loss of a modularized multi-level converter under low-power operation.
Background
MMC (Modular Multilevel Converter, modularized multi-level converter) adopts a modularized structure, and has the advantages of high reliability, good output characteristic, flexible structure adjustment, redundancy control realization and the like, and is widely focused in the fields of flexible direct current transmission, renewable energy grid connection, motor driving and the like.
Because the switching frequency of the modularized multi-level converter submodule power device is higher, larger switching loss can be generated, the service life of the device is reduced, and the running cost of the MMC is increased. When the MMC operates at low power, bridge arm current is smaller, capacitor voltage fluctuation is smaller, but in the case of higher power operation, switching frequency of a power device is not obviously reduced. Therefore, the switching loss of the power device still has a larger optimization space under the MMC low-power operation, and the lower switching loss is beneficial to the efficient and stable operation of the modularized multi-level converter system.
Aiming at the problem of optimizing the loss of the modularized multi-level converter, the conventional method achieves the purpose of reducing the loss by changing the topological structure of the modularized multi-level converter circuit or a method for re-matching the modulation strategy, but the method can cause the problems of increasing the construction cost of the modularized multi-level converter, increasing the complexity of a control algorithm and the like, and limits the application of the method in practical engineering.
In order to solve the above-mentioned problems, a method for optimizing the switching loss of a modular multilevel converter under low-power operation needs to be designed.
Disclosure of Invention
The invention aims to solve the technical problems of the prior art and provides a modularized multi-level converter switching loss optimization method under low-power operation, which reduces the average switching times of sub-modules under the condition of ensuring that the fluctuation rate of capacitor voltage is lower than 10% by reducing the control period of capacitor voltagen ave Average switching losses with submodulesP loss The purposes of reducing the loss of the device and prolonging the service life of the device are realized.
The invention is realized by adopting the following technical scheme for solving the technical problems:
the invention provides a method for optimizing the switching loss of a modularized multi-level converter under low-power operation, which specifically comprises the following steps:
s1, based on an alternating-current side current model of a modularized multi-level converter, sampling in a bridge arm when the modular multi-level converter operates at a low power levelNSub-module switch signalS i And bridge arm currenti arm The method comprises the steps of carrying out a first treatment on the surface of the Wherein the submodule switch signalS i Expressed as:
Figure 205812DEST_PATH_IMAGE001
(1)
wherein the method comprises the steps ofi=1,2…N。
S2, calculating a fundamental frequency period
Figure 388663DEST_PATH_IMAGE002
Inner partNCapacitance-voltage variation delta of individual sub-modulesu ci (i=1,2…N) The method comprises the steps of carrying out a first treatment on the surface of the During low power operation of the modular multilevel converter, one fundamental frequency period
Figure 703361DEST_PATH_IMAGE003
Capacitance-voltage variation of each sub-module in the circuit
Figure 438099DEST_PATH_IMAGE004
：
Figure 624099DEST_PATH_IMAGE005
(2)
Wherein, Cis the capacitance of the sub-module.
S3, according to the average capacitance voltage of the submoduleU sm Calculating the fluctuation rate of the capacitance voltage of the submodule
Figure 266433DEST_PATH_IMAGE006
，
Figure 605010DEST_PATH_IMAGE007
(3)
Then, the maximum value of the capacitor voltage fluctuation rate of the bridge arm submodule is obtained by comparing the capacitor voltage fluctuation rates of all the submodules
Figure 41808DEST_PATH_IMAGE008
：
Figure 482148DEST_PATH_IMAGE009
(4)
Wherein,
Figure 662593DEST_PATH_IMAGE010
representing the capacitor voltage ripple rate of each sub-module.
S4, if the capacitance voltage fluctuation rate of each sub-module is maximum
Figure 386836DEST_PATH_IMAGE011
Less than 10%, i.e. the capacitor voltage fluctuation is within a reasonable range, the capacitor voltage control period is reducedT control Thereby achieving the reduction of submodule averageNumber of switching timesn ave Average switching losses with submodulesP loss Is a target of (a).
Wherein the average switching times of the bridge arm neutron modulesn ave With the period of the fundamental frequencyT f Is increased and decreased, the average switching times of the sub-modules in the bridge armn ave With the period of the fundamental frequencyT f Is increased by decreasing.
Average switching loss of sub-modulesP loss According to the formula
Figure 260114DEST_PATH_IMAGE012
The method can be used for obtaining the product,P swT1 、P swT2 、P swD1 、P swD2 the calculation method of (a) specifically comprises the following steps:
Figure 312383DEST_PATH_IMAGE014
(5)
in the formula (5) of the present invention,i T1 for flowing through the first power switchTThe magnitude of the current of 1 is that,i T2 for flowing through the second power switchTThe magnitude of the current of 2 is that of,i D1 for flowing through the first diodeDThe magnitude of the current of 1 is that,i D2 for flowing through the second diodeDThe magnitude of the current of 2 is that of,E on () As a function of the on-state energy of the power switch,E off () For the power switch to turn off the energy function,E rec () As a function of the reverse recovery energy of the diode,U sm is the average capacitance voltage of the sub-module.
If the bridge arm currenti arm >0 and 0S i =1 at this timei T1 =0，i T _jn2 =0，i D1 =i arm ，i D2 =0; if the bridge arm currenti arm >0 and 0S i =0, at this timei T1 =0，i T2 =i arm ，i D1 =0，i D2 =0; if the bridge arm currenti arm <0 and 0S i =1 at this timei T1 =-i arm ，i T2 =0，i D1 =0，i D2 =0; if the bridge arm currenti arm <0 and 0S i =0, at this timei T1 =0，i T2 =0，i D1 =0，i D2 =-i arm 。
Because the bridge arm current is smaller under low power, the capacitor voltage control period in the S2 is reducedT control After that, the capacitor voltage fluctuation rate in the S3
Figure 410701DEST_PATH_IMAGE015
The average switching times of the S4 neutron module are reduced under the condition that the fluctuation rate of the capacitor voltage is ensured to be lower than 10 percentn ave Average switching losses with submodulesP loss The purposes of reducing the loss of the device and prolonging the service life of the device are realized.
In another aspect, the present invention also proposes an electronic device comprising a memory, a processor and program instructions stored in the memory for execution by the processor, the processor executing the program instructions to carry out the steps of the aforementioned method of the invention.
The technical scheme adopted by the invention has the following beneficial technical effects:
1. according to the modularized multi-level converter switching loss optimization method under low-power operation, the average switching times of the submodules and the average switching loss of the submodules are reduced by adjusting the capacitor voltage control period, the purposes of reducing the device loss and prolonging the service life of the device are achieved, and the control algorithm is simple and easy to implement.
2. The modularized multi-level converter switching loss optimization method under low-power operation does not need to change the topological structure of the modularized multi-level converter sub-module, does not increase the construction cost of the modularized multi-level converter, is easy to implement in the existing modularized multi-level converter system, and has strong practicability.
3. The modularized multi-level converter switching loss optimization method under low-power operation can ensure that capacitor voltage fluctuation is in a reasonable range and hardly influences output electric energy quality.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to those skilled in the art that other drawings can be obtained according to these drawings without inventive effort.
Fig. 1 is a schematic diagram of a three-phase modular multilevel converter topology according to an embodiment of the invention.
Fig. 2 is a schematic diagram of a half-bridge submodule topology according to an embodiment of the present invention.
FIG. 3 is a schematic overall process flow diagram of an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention provides a method for optimizing the switching loss of a modularized multi-level converter under low-power operation aiming at the problem of optimizing the loss of the modularized multi-level converter under the fault of a submodule, wherein the topological structures of a three-phase modularized multi-level converter and the submodule are shown as figure 1 and figure 2, the three-phase modularized multi-level converter consists of six bridge arms, and each bridge arm comprisesN（NPositive integer) of Sub-modules (SM) with identical topology and a bridge arm inductanceL 0 The method comprises the steps of carrying out a first treatment on the surface of the The sub-module is of a half-bridge structure and consists of two diodesD1、D2, two IGBT power switchesT1、T2 and a capacitorC 0 Composition is prepared.
As shown in fig. 3, a method for optimizing switching loss of a modular multilevel converter under low power operation includes: based on a current model of an alternating current side of the modularized multi-level converter, sampling a submodule switching signal and bridge arm current when the modularized multi-level converter operates at a low power level, and calculating the capacitance voltage variation quantity and the capacitance voltage fluctuation rate of each submodule in a fundamental frequency period; when the modularized multi-level converter operates at a low power level, bridge arm current is smaller, the capacitance voltage fluctuation rate of the submodule is smaller, and if the capacitance voltage fluctuation rate of the submodule is smaller than 10%, the capacitance voltage control period can be shortened, so that the purposes of reducing switching frequency and switching loss are achieved.
The optimization method specifically comprises the following steps:
s1, based on an alternating-current side current model of a modularized multi-level converter, sampling in a bridge arm when the modular multi-level converter operates at a low power levelNSub-module switch signalS i (i=1,2…N) And bridge arm currenti arm ；
S2, calculating a fundamental frequency periodT funda Inner partNCapacitance-voltage variation delta of individual sub-modulesu ci (i=1,2…N)；
S3, according to the average capacitance voltage of the submoduleU sm Calculating the fluctuation rate of the capacitance voltage of the submodule
Figure 723871DEST_PATH_IMAGE016
Comparing to obtain the maximum value of the fluctuation rate of the capacitor voltage of the cliff neutron module
Figure 502471DEST_PATH_IMAGE017
；
S4, if each submodule capacitor voltage waveMaximum value of dynamic ratio
Figure 307616DEST_PATH_IMAGE017
Less than 10%, i.e. the capacitor voltage fluctuation is within a reasonable range, the capacitor voltage control period is reducedT control Thereby reducing the average switching times of the submodulesnAverage switching losses with submodulesP loss Is a target of (a).
The submodule switch signals in S1S i Can be expressed as:
Figure 705230DEST_PATH_IMAGE018
(1)
the modular multilevel converter in the S2 operates at low power with a fundamental frequency periodT funda Capacitance-voltage variation of each sub-module in the circuit
Figure 13852DEST_PATH_IMAGE019
：
Figure 87987DEST_PATH_IMAGE020
(2)
In the formula (2),Cis the capacitance of the sub-module.
The fluctuation rate of the capacitance voltage of the submodule in the step S3
Figure 849270DEST_PATH_IMAGE021
：
Figure 814690DEST_PATH_IMAGE022
(3)
In the formula (3),U sm is the average capacitance voltage of the sub-module.
In the step S3, the maximum value of the voltage fluctuation rate of the capacitance of the bridge arm submodule can be obtained by comparing the voltage fluctuation rates of the submodules
Figure 712238DEST_PATH_IMAGE023
：
Figure 35904DEST_PATH_IMAGE024
(4)
The average switching times of the sub-modules in the bridge arm in the S4n ave With the period of the fundamental frequencyT f Is increased and decreased, the average switching times of the sub-modules in the bridge armn ave With the period of the fundamental frequencyT f Is increased by decreasing.
Average switching loss of S4 neutron moduleP loss According to the formula
Figure 284482DEST_PATH_IMAGE025
The obtained value is obtained,P swT1 、P swT2 、P swD1 、P swD2 the calculation method of (a) specifically comprises the following steps:
Figure 273167DEST_PATH_IMAGE026
(5)
in the formula (5) of the present invention,i T1 for flowing through the first power switchTThe magnitude of the current of 1 is that,i T2 for flowing through the second power switchTThe magnitude of the current of 2 is that of,i D1 for flowing through the first diodeDThe magnitude of the current of 1 is that,i D2 for flowing through the second diodeDThe magnitude of the current of 2 is that of,E on () As a function of the on-state energy of the power switch,E off () For the power switch to turn off the energy function,E rec () As a function of the reverse recovery energy of the diode,U sm is the average capacitance voltage of the sub-module.
If the bridge arm current in S4i arm >0 and 0S i =1 at this timei T1 =0，i T _jn2 =0，i D1 =i arm ，i D2 =0; if the bridge arm currenti arm >0 and 0S i =0, at this timei T1 =0，i T2 =i arm ，i D1 =0，i D2 =0; if the bridge arm currenti arm <0 and 0S i =1 at this timei T1 =-i arm ，i T2 =0，i D1 =0，i D2 =0; if the bridge arm currenti arm <0 and 0S i =0, at this timei T1 =0，i T2 =0，i D1 =0，i D2 =-i arm 。
Because the bridge arm current is smaller under low power, the capacitor voltage control period in the S2 is reducedT control After that, the capacitor voltage fluctuation rate in the S3
Figure 399124DEST_PATH_IMAGE027
The average switching times of the S4 neutron module are reduced under the condition that the fluctuation rate of the capacitor voltage is ensured to be lower than 10 percentn ave Average switching losses with submodulesP loss The purposes of reducing the loss of the device and prolonging the service life of the device are realized.
The present embodiment also proposes an electronic device comprising a memory, a processor and program instructions stored in the memory for execution by the processor, the processor executing the program instructions to perform the steps of the proposed method.
It should be noted that, the description of the technical solution of the apparatus in this embodiment of the present application is similar to the description of the foregoing method embodiment, and has similar beneficial effects as the method embodiment, so that a detailed description is omitted.
Program code for carrying out methods of the present application may be written in any combination of one or more programming languages. These program code may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus such that the program code, when executed by the processor or controller, causes the functions/operations specified in the flowchart and/or block diagram to be implemented. The program code may execute entirely on the machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.
In the description of the present specification, the descriptions of the terms "one embodiment," "example," "specific example," and the like, mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing has shown and described the basic principles, principal features and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims.

Claims (7)

1. A modularized multi-level converter switching loss optimization method under low power operation is provided, wherein the modularized multi-level converter consists of six bridge arms, and each bridge arm comprisesNSub-modules with same topological structure and bridge arm inductorL 0 The method comprises the steps of carrying out a first treatment on the surface of the The sub-module is a half-bridge structure and comprises a first diode D1, a second diode D2, a first power switch T1, a second power switch T2 and a capacitorC 0 The method is characterized in that the switching loss optimization method for each bridge arm comprises the following steps:
s1, modular multi-level converterAn ac side current model for sampling each sub-module in the leg for a fundamental frequency period of ac side voltage of the modular multilevel converter when operating at low power levels
Figure QLYQS_1
Switch signal->
Figure QLYQS_2
And bridge arm current->
Figure QLYQS_3
The method comprises the steps of carrying out a first treatment on the surface of the Wherein->
Figure QLYQS_4
Expressed as:
Figure QLYQS_5
wherein,
Figure QLYQS_6
；
s2, calculating a fundamental frequency period
Figure QLYQS_7
Capacitance-voltage variation of individual submodules of the bridge arm +.>
Figure QLYQS_8
；
S3, according to rated capacitance voltage of the sub-module
Figure QLYQS_9
Calculating the fluctuation rate of the capacitance voltage of the submodule +.>
Figure QLYQS_10
Comparing to obtain maximum value +.>
Figure QLYQS_11
；
S4, if the capacitance voltage fluctuation rate of each sub-module is maximum
Figure QLYQS_12
When the voltage is smaller than the set fluctuation ratio threshold value, the capacitor voltage control period is increased>
Figure QLYQS_13
；
Average switching loss of sub-modules
Figure QLYQS_14
Wherein:
Figure QLYQS_15
in the above-mentioned method, the step of,
Figure QLYQS_17
for flowing through the first power switchTCurrent magnitude of 1, +.>
Figure QLYQS_20
For flowing through the second power switchT2, current magnitude +.>
Figure QLYQS_22
For flowing through the first diodeDCurrent magnitude of 1, +.>
Figure QLYQS_18
For flowing through the second diodeD2, current magnitude +.>
Figure QLYQS_21
For the power switch to conduct the energy function, +.>
Figure QLYQS_23
For the power switch to switch off the energy function, +.>
Figure QLYQS_24
As a function of the reverse recovery energy of the diode,
Figure QLYQS_16
is the rated capacitance voltage of the submodule;
Figure QLYQS_19
The average switching times of the submodules;
if the bridge arm current
Figure QLYQS_25
And->
Figure QLYQS_26
At this time->
Figure QLYQS_27
；
If the bridge arm current
Figure QLYQS_28
And->
Figure QLYQS_29
At this time->
Figure QLYQS_30
；
If the bridge arm current
Figure QLYQS_31
And->
Figure QLYQS_32
At this time->
Figure QLYQS_33
；
If the bridge arm current
Figure QLYQS_34
And->
Figure QLYQS_35
At this time->
Figure QLYQS_36
。
2. The method for optimizing switching losses of a modular multilevel converter during low power operation according to claim 1, wherein the modular multilevel converter in step S2 is operated at low power for a fundamental frequency period
Figure QLYQS_37
The capacitance-voltage variation of each submodule in the circuit>
Figure QLYQS_38
：
Figure QLYQS_39
Wherein C is the capacitance of the sub-module.
3. The method for optimizing switching losses of a modular multilevel converter under low power operation according to claim 1, wherein the submodule capacitor voltage ripple in step S3
Figure QLYQS_40
：
Figure QLYQS_41
Wherein,
Figure QLYQS_42
is the rated capacitor voltage of the sub-module.
4. A low power operation according to claim 1The lower modularized multi-level converter switching loss optimization method is characterized in that in step S3, the maximum value of the capacitor voltage fluctuation rate of the bridge arm submodule is obtained by comparing the capacitor voltage fluctuation rates of all submodules
Figure QLYQS_43
：
Figure QLYQS_44
Wherein,
Figure QLYQS_45
the capacitor voltage fluctuation rate for each sub-module.
5. The method for optimizing switching losses of a modular multilevel converter under low power operation according to claim 1, wherein in step S4, the average switching times of the sub-modules in the bridge arm are
Figure QLYQS_46
Control period along with capacitor voltage>
Figure QLYQS_47
Is reduced by increasing the average switching times of the sub-modules in the bridge arm +.>
Figure QLYQS_48
Control period along with capacitor voltage>
Figure QLYQS_49
Is increased by decreasing.
6. A method of optimizing switching losses in a modular multilevel converter under low power operation according to claim 3, wherein the ripple threshold set in step S4 is 10%.
7. An electronic device comprising a memory, a processor and program instructions stored in the memory for execution by the processor, wherein the processor executes the program instructions to perform the steps of the method of any one of claims 1-6.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106787883B (en) * 2017-01-24 2019-11-08 特变电工新疆新能源股份有限公司 The pressure modulator approach approached based on nearest level and press modulating device
CN107181419A (en) * 2017-06-06 2017-09-19 江苏大学 A kind of Modularized multi-level converter sub-module electric capacity optimizes method for equalizing voltage
CN107086803B (en) * 2017-06-19 2019-04-09 国家电网公司 A kind of capacitor voltage balance control strategy of modularization multi-level converter
CN111030485A (en) * 2018-10-10 2020-04-17 长沙理工大学 MMC capacitor voltage-sharing method based on nonlinear current algorithm
CN110829870B (en) * 2019-10-28 2021-01-12 杭州电子科技大学 Control method of modular multilevel converter in low-frequency operation state
CN114710047B (en) * 2022-04-06 2024-03-22 东南大学 Loss balance control method for full-bridge modular multilevel converter
CN115275922A (en) * 2022-07-01 2022-11-01 国网宁夏电力有限公司 Line interphase short-circuit fault property identification method and system by using energy storage capacitor

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