CN114499133A - Method for eliminating primary current harmonic of MMC type DC-DC converter - Google Patents

Method for eliminating primary current harmonic of MMC type DC-DC converter Download PDF

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CN114499133A
CN114499133A CN202210327815.5A CN202210327815A CN114499133A CN 114499133 A CN114499133 A CN 114499133A CN 202210327815 A CN202210327815 A CN 202210327815A CN 114499133 A CN114499133 A CN 114499133A
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phase shift
shift angle
primary current
current harmonic
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敖健永
余玉晗
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Yangjiang Power Supply Bureau of Guangdong Power Grid Co Ltd
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Yangjiang Power Supply Bureau of Guangdong Power Grid Co Ltd
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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
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/02—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for dc mains or dc distribution networks
    • H02J1/14—Balancing the load in a network
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac

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Abstract

The invention provides a method for eliminating primary current harmonic of an MMC type DC-DC converter, which defines the primary current harmonic of the high-voltage side of the MMC type DC-DC converter by analyzing the basic operation mechanism of the MMC type DC-DC converter and acquires the amplitude of the primary current harmonic; and then, taking the primary current harmonic amplitude of the MMC type DC-DC converter as a target function, changing the carrier phase shift angle combination of each submodule and carrying out continuous iterative calculation, and comparing the primary current ripple sizes of the converters under different phase shift angles to select the optimal phase shift angle combination, thereby achieving the purpose of reducing the current harmonic of the high-voltage side. The problem of in the energy storage application occasion of high pressure, large capacity, DC-DC converter based on MMC is used for the direct current ripple increase of high-pressure side when energy storage system inserts direct current electric wire netting is solved.

Description

Method for eliminating primary current harmonic of MMC type DC-DC converter
Technical Field
The invention belongs to the technical field of intelligent power grid energy storage systems, and particularly relates to a method for eliminating primary current harmonic waves of an MMC type DC-DC converter.
Background
In a direct-current power distribution and utilization system, the reasonable configuration of the energy storage system can effectively smooth the output of the renewable energy system, and achieves a certain peak clipping and valley filling effect. In the application occasions of high-voltage and large-capacity energy storage, due to the limitation of voltage balance, the energy storage system is difficult to adopt a large number of monomers or assemblies to be connected in series. To solve this problem, additional equalization circuits are often required in the converter to implement voltage equalization control, however this further increases the cost of the system and the complexity of control. For the energy storage conversion scheme adopting the H-bridge cascade converter as the AC power grid, the DC-DC converter based on the MMC can be used for the energy storage system to be connected into the DC power grid so as to reduce the voltage level of each energy storage module.
The DC-DC converter based on the MMC has remarkable advantages when being used in high-voltage and high-power energy storage occasions, and has the characteristics that the voltage and current stress of a switching device is small, and the required inductance under the condition of the same output current ripple is only 1/N2(N is the number of cascaded modules) of a single half-bridge topology; however, since the state of charge (SOC) of each energy storage battery is difficult to maintain balanced all the time, the corresponding duty ratios of the submodules are not consistent, which further causes the dc ripple of the submodules on the high voltage side to increase.
Disclosure of Invention
In view of this, the present invention is directed to solve the problem that a DC-DC converter based on an MMC increases a DC ripple on a high-voltage side when an energy storage system is connected to a DC power grid in an energy storage application with high voltage and large capacity.
In order to solve the technical problems, the invention provides the following technical scheme:
the invention provides a method for eliminating primary current harmonic waves of an MMC type DC-DC converter, which comprises the following steps:
the method comprises the following steps of defining a primary current harmonic vector of the MMC type DC-DC converter by utilizing the duty ratio of each submodule, wherein the definition formula of the primary current harmonic vector is as follows:
Figure 607758DEST_PATH_IMAGE001
in the formula (I), the compound is shown in the specification,
Figure 51509DEST_PATH_IMAGE002
representing the vector of the harmonics of the primary current,
Figure 205410DEST_PATH_IMAGE003
representing the phase shift angle combination of N sub-modules,
Figure 25598DEST_PATH_IMAGE004
the number of sub-modules is indicated,
Figure 378082DEST_PATH_IMAGE005
is shown as
Figure 258313DEST_PATH_IMAGE006
The harmonic coefficients of the primary currents of the sub-modules,
Figure 633931DEST_PATH_IMAGE007
indicates to be
Figure 54548DEST_PATH_IMAGE006
The harmonic coefficient of the primary current of the sub-module is taken as
Figure 464801DEST_PATH_IMAGE006
The reference phase shift angle of the individual sub-modules,
Figure 250354DEST_PATH_IMAGE008
in which
Figure 175585DEST_PATH_IMAGE009
Is shown as
Figure 331717DEST_PATH_IMAGE006
The dc side voltage on the low side of the sub-module,
Figure 596476DEST_PATH_IMAGE010
is shown as
Figure 880827DEST_PATH_IMAGE006
The duty cycle of the sub-module;
iteratively calculating the amplitude of the primary current harmonic vector under different phase shift angle combinations until a set condition is met;
and executing the phase shift angle combination meeting the set condition as the reference phase shift angle combination of the next control period.
Further, it is to
Figure 231036DEST_PATH_IMAGE006
Duty cycle of sub-module
Figure 931139DEST_PATH_IMAGE010
The calculation formula (2) is specifically as follows:
Figure 112722DEST_PATH_IMAGE011
in the formula (I), the compound is shown in the specification,
Figure 505657DEST_PATH_IMAGE012
is shown as
Figure 343163DEST_PATH_IMAGE006
The dc side voltage on the high side of the sub-module,
Figure 909274DEST_PATH_IMAGE013
is shown as
Figure 883046DEST_PATH_IMAGE006
The transmission power of the sub-modules is,
Figure 446882DEST_PATH_IMAGE014
representing the total transmission power of the N sub-modules.
Further, iteratively calculating the amplitudes of the first current harmonic vectors under different phase shift angle combinations until the set conditions are met specifically includes:
definitional setting objective function based on primary current harmonic vector
Figure 771684DEST_PATH_IMAGE015
，
Figure 100002_DEST_PATH_IMAGE016
Wherein
Figure 813590DEST_PATH_IMAGE017
Representing the first current harmonic when the phase shift angle of the first submodule is set to the reference phase shift angleThe wave vector, for the same reason,
Figure 907448DEST_PATH_IMAGE018
representing a primary current harmonic vector when the phase shift angle of the Nth sub-module is set as a reference phase shift angle;
and (4) iteratively calculating the objective function value under different phase shift angle combinations until the objective function value is not greater than the set maximum error limit, so that the amplitude of the primary current harmonic vector meets the set condition.
Further, the maximum error limit is specifically set as:
Figure 704502DEST_PATH_IMAGE019
in the formula (I), the compound is shown in the specification,
Figure 251021DEST_PATH_IMAGE020
is the maximum error limit.
Further, iteratively calculating the amplitudes of the first current harmonic vectors under different phase shift angle combinations until the set conditions are met specifically includes:
setting a unit stepping phase shift angle and iteration cycle time;
calculating the amplitude of a primary current harmonic vector under the current phase shift angle combination by using the unit stepping phase shift angle;
and judging whether the amplitude of the primary current harmonic vector under the current phase shift angle combination meets a set condition within the iteration cycle time, if not, continuously updating the phase shift angle combination, iteratively calculating the amplitude of the corresponding primary current harmonic vector until the set condition is met, and taking the phase shift angle combination meeting the set condition as a reference phase shift angle combination so as to carry out subsequent steps.
Further, calculating the amplitude of the first current harmonic vector under the current phase shift angle combination by using the unit step phase shift angle specifically comprises:
calculating the first current harmonic error of the phase shift angle combination in two iteration directions when the unit stepping phase shift angle is increased or decreased;
and judging the magnitude of the primary current harmonic error in the two iteration directions, and selecting the iteration direction with the smaller primary current harmonic error for calculation in the next iteration calculation.
Further, the first current harmonic error in two iteration directions is specifically:
Figure 362197DEST_PATH_IMAGE021
in the formula (I), the compound is shown in the specification,
Figure 372878DEST_PATH_IMAGE022
representing the first current harmonic error of the phase shift angle combination at increasing unit step phase shift angle,
Figure 278517DEST_PATH_IMAGE023
representing the first current harmonic error of the phase shift angle combination in reducing the unit step phase shift angle,
Figure 312332DEST_PATH_IMAGE024
representing the unit step phase shift angle.
In summary, the invention provides a method for eliminating a primary current harmonic of an MMC type DC-DC converter, which defines a primary current harmonic of a high-voltage side of the MMC type DC-DC converter by analyzing a basic operation mechanism of the MMC type DC-DC converter and obtains an amplitude of the primary current harmonic; and then, taking the primary current harmonic amplitude of the MMC type DC-DC converter as a target function, changing the carrier phase shift angle combination of each submodule and carrying out continuous iterative calculation, and comparing the primary current ripple sizes of the converters under different phase shift angles to select the optimal phase shift angle combination, thereby achieving the purpose of reducing the current harmonic of the high-voltage side. The problem of in the energy storage application occasion of high pressure, large capacity, DC-DC converter based on MMC is used for the direct current ripple increase of high-pressure side when energy storage system inserts direct current electric wire netting is solved.
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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 embodiments or the description of the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive labor.
Fig. 1 is a schematic flowchart of a method for eliminating a primary current harmonic of an MMC DC-DC converter according to an embodiment of the present invention;
fig. 2 is a schematic flowchart of iterative computation in a primary current harmonic cancellation method of an MMC DC-DC converter according to an embodiment of the present invention.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the embodiments described below are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In a direct-current power distribution and utilization system, the reasonable configuration of the energy storage system can effectively smooth the output of the renewable energy system, and achieves a certain peak clipping and valley filling effect. In the application occasions of high-voltage and large-capacity energy storage, due to the limitation of voltage balance, the energy storage system is difficult to adopt a large number of monomers or assemblies to be connected in series. To solve this problem, additional equalization circuits are often required in the converter to implement voltage equalization control, however this further increases the cost of the system and the complexity of control. For the energy storage conversion scheme adopting the H-bridge cascade converter as the AC power grid, the DC-DC converter based on the MMC can be used for the energy storage system to be connected into the DC power grid so as to reduce the voltage level of each energy storage module.
The DC-DC converter based on the MMC has remarkable advantages when being used in high-voltage and high-power energy storage occasions, and has the characteristics that the voltage and current stress of a switching device is small, and the required inductance under the condition of the same output current ripple is only 1/N2(N is the number of cascaded modules) of a single half-bridge topology; however, since the state of charge (SOC) of each energy storage battery is difficult to maintain balanced all the time, the corresponding duty ratios of the submodules are not consistent, which further causes the dc ripple of the submodules on the high voltage side to increase.
Based on the method, the invention provides a method for eliminating the primary current harmonic of the MMC type DC-DC converter.
The following is a detailed description of an embodiment of a method for eliminating a first harmonic of a current of an MMC DC-DC converter according to the present invention.
Referring to fig. 1 and fig. 2, the present embodiment provides a method for eliminating a first harmonic of a current of an MMC DC-DC converter, including the following steps:
s100: and defining a primary current harmonic vector of the MMC type DC-DC converter by utilizing the duty ratio of each submodule.
Analyzing the basic operation mechanism of the MMC type DC-DC converter can know that the inconsistency of the duty ratios corresponding to the submodules directly causes the direct current ripple on the high-voltage side to be increased. In order to reduce the direct current ripple on the high-voltage side, the embodiment of the application defines the primary current harmonic vector of the converter according to the duty ratio of the sub-module, and establishes the relationship between the duty ratio of the sub-module and the direct current ripple on the high-voltage side, so that the phase shift angle combination of the sub-module when the direct current ripple on the high-voltage side is minimum can be conveniently obtained.
The acquisition of data and the initialization phase are first required before the primary current harmonic vector is defined and calculated. Specifically, data acquisition includes simultaneously acquiring the transmission power of each sub-module
Figure 758357DEST_PATH_IMAGE013
Direct current side voltage of low voltage side
Figure 826807DEST_PATH_IMAGE009
And a DC side voltage of the high voltage side
Figure 897488DEST_PATH_IMAGE012
(ii) a The initialization parameters include unit step phase shift angle
Figure 418600DEST_PATH_IMAGE024
Update cycle time
Figure 668315DEST_PATH_IMAGE025
And maximum error limit
Figure 591272DEST_PATH_IMAGE020
And setting the initialization phase shift angle of each sub-module
Figure 838714DEST_PATH_IMAGE026
。
According to the collected transmission power of each sub-module
Figure 909438DEST_PATH_IMAGE013
Direct current side voltage of low voltage side
Figure 900528DEST_PATH_IMAGE009
And a DC side voltage of the high voltage side
Figure 677991DEST_PATH_IMAGE012
To calculate the duty ratio corresponding to each sub-module
Figure 158651DEST_PATH_IMAGE010
. The calculation formula of the duty ratio is specifically expressed as:
Figure 388775DEST_PATH_IMAGE027
（1）
in the formula (I), the compound is shown in the specification,
Figure 183556DEST_PATH_IMAGE012
is shown as
Figure 877842DEST_PATH_IMAGE006
The dc side voltage on the high side of the sub-module,
Figure 467086DEST_PATH_IMAGE013
is shown as
Figure 450086DEST_PATH_IMAGE006
The transmission power of the sub-modules is,
Figure 845295DEST_PATH_IMAGE014
representing the total transmission power of the N sub-modules,
Figure 331771DEST_PATH_IMAGE004
the number of sub-modules is indicated.
Further, the first current harmonic coefficient of each sub-module may be calculated as:
Figure 357496DEST_PATH_IMAGE028
（2）
in the formula (I), the compound is shown in the specification,
Figure 624529DEST_PATH_IMAGE005
is shown as
Figure 495533DEST_PATH_IMAGE006
The harmonic coefficients of the primary currents of the sub-modules,
Figure 102095DEST_PATH_IMAGE009
is shown as
Figure 361038DEST_PATH_IMAGE006
The dc side voltage of the low side of the sub-module.
Combining equations (1) and (2), the primary current harmonic vector of the MMC-type DC-DC converter can be expressed as,
Figure 787472DEST_PATH_IMAGE029
（3）
in the formula (I), the compound is shown in the specification,
Figure 790063DEST_PATH_IMAGE002
representing the vector of the harmonics of the primary current,
Figure 251131DEST_PATH_IMAGE003
representing the phase shift angle combination of N sub-modules,
Figure 347220DEST_PATH_IMAGE007
indicates to be
Figure 588845DEST_PATH_IMAGE006
The harmonic coefficient of the primary current of the sub-module is taken as
Figure 67231DEST_PATH_IMAGE006
Reference phase shift angles of the individual submodules.
S200: and (4) iteratively calculating the amplitude of the primary current harmonic vector under different phase shift angle combinations until a set condition is met.
According to the analysis and definition, the primary current harmonic vector of the MMC DC-DC converter can be obtained, and in order to effectively reduce the primary current harmonic to reduce the size and weight of the filter element, an objective function can be set
Figure 382806DEST_PATH_IMAGE015
Specifically, it can be expressed as:
Figure 983552DEST_PATH_IMAGE030
（4）
wherein
Figure 384577DEST_PATH_IMAGE017
Indicating the first current harmonic vector when the phase shift angle of the first sub-module is set to the reference phase shift angle, and, similarly,
Figure 728971DEST_PATH_IMAGE018
indicating the first current harmonic vector when the phase shift angle of the nth sub-module is set as the reference phase shift angle.
The objective function means setting the phase shift angle of the first sub-module as the reference phase shift angle, and then selecting the appropriate phase shift angle combination
Figure 164631DEST_PATH_IMAGE031
So as to minimize the magnitude of the primary current harmonic vector of the DC-DC converter, and the above selection process is performed by iterative calculations.
In the iterative calculation process of executing the algorithm, a proper maximum error limit needs to be set
Figure 608382DEST_PATH_IMAGE020
Whether iteration is terminated is judged, the maximum error limit can be selected as the maximum value of the first harmonic of the inductive current in the iteration process and is continuously updated, and the maximum error limit can be expressed as:
Figure 762283DEST_PATH_IMAGE032
（5）
based on the objective function set by the definition formula of the primary current harmonic vector, when the objective function value under different combinations of the phase shift angles is calculated iteratively and is not greater than the set maximum error limit, the amplitude of the primary current harmonic vector at the moment can be considered to meet the set condition.
The iterative computation of the amplitude of the first current harmonic vector under different phase shift angle combinations until the set conditions are met comprises the following steps:
s201: and setting a unit step phase shifting angle and iteration cycle time.
S202: and calculating the amplitude of the primary current harmonic vector under the current phase shift angle combination by using the unit stepping phase shift angle.
When performing the iterative computation, it is necessary to determine an iterative direction to perform the iterative computation. Specifically, there are two iteration directions, i.e., can be
Figure 644788DEST_PATH_IMAGE033
Can also be
Figure 934955DEST_PATH_IMAGE034
. When selecting the iteration direction, the first current harmonic error in two iteration directions should be judged and calculated first
Figure 549607DEST_PATH_IMAGE022
(corresponding to an increase in
Figure 987542DEST_PATH_IMAGE024
) And
Figure 611421DEST_PATH_IMAGE023
(corresponding to reduction in
Figure 818412DEST_PATH_IMAGE024
) It can be expressed in particular as:
Figure 869544DEST_PATH_IMAGE035
（6）
in the formula (I), the compound is shown in the specification,
Figure 732458DEST_PATH_IMAGE022
representing the first current harmonic error of the phase shift angle combination at increasing unit step phase shift angle,
Figure 956766DEST_PATH_IMAGE023
representing the first current harmonic error of the phase shift angle combination in reducing the unit step phase shift angle,
Figure 221525DEST_PATH_IMAGE024
representing the unit step phase shift angle.
S203: and judging whether the amplitude of the primary current harmonic vector under the current phase shift angle combination meets a set condition within the iteration cycle time, if not, continuously updating the phase shift angle combination, iteratively calculating the amplitude of the corresponding primary current harmonic vector until the set condition is met, and taking the phase shift angle combination meeting the set condition as a reference phase shift angle combination so as to carry out subsequent steps.
Namely, the first current harmonic error in two iteration directions when the phase shift angle combination is increased or decreased in unit stepping phase shift angle needs to be calculated; and judging the magnitude of the primary current harmonic error in the two iteration directions, and selecting the iteration direction with the smaller primary current harmonic error for calculation in the next iteration calculation. Utensil for cleaning buttockPhysically, if the iteration error of the two is satisfied
Figure 443559DEST_PATH_IMAGE036
Then the reference phase shift angle calculated iteratively in the next step should be selected
Figure 528190DEST_PATH_IMAGE033
(ii) a Otherwise, the reference phase shift angle of the next iteration calculation should be selected as
Figure 556189DEST_PATH_IMAGE034
。
And performing iterative computation on different phase shift angle combinations according to the iterative computation method until the primary current harmonic corresponding to the selected phase shift angle combination meets the set iterative error limit.
S300: and executing the phase shift angle combination meeting the set condition as the reference phase shift angle combination of the next control period.
Within the set iteration period time Tr, if the iteration calculation result of the selected phase shift angle combination meets the set iteration error limit, the iteration can be stopped and the phase shift angle combination is used as the reference phase shift angle combination of the next control period to be executed; otherwise, go back to S200 to continue to perform new iterative calculations.
The embodiment provides a method for eliminating primary current harmonic of an MMC type DC-DC converter, which defines the primary current harmonic of the high-voltage side of the MMC type DC-DC converter by analyzing the basic operation mechanism of the MMC type DC-DC converter and acquires the amplitude of the primary current harmonic; and then, taking the primary current harmonic amplitude of the MMC type DC-DC converter as a target function, changing the carrier phase shift angle combination of each submodule and carrying out continuous iterative calculation, and comparing the primary current ripple sizes of the converters under different phase shift angles to select the optimal phase shift angle combination, thereby achieving the purpose of reducing the current harmonic of the high-voltage side. Compared with the traditional carrier phase shift calculation, the method can effectively reduce the high-voltage side current harmonic of the MMC type DC-DC converter, and reduce the size of a high-voltage side filter reactor, thereby reducing the system cost.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (7)

  1. A method for eliminating a primary current harmonic of an MMC type DC-DC converter is characterized by comprising the following steps:
    defining a primary current harmonic vector of the MMC type DC-DC converter by utilizing the duty ratio of each submodule, wherein the definition formula of the primary current harmonic vector is specifically as follows:
    Figure 777365DEST_PATH_IMAGE001
    in the formula (I), the compound is shown in the specification,
    Figure 833046DEST_PATH_IMAGE002
    representing the vector of the harmonics of the primary current,
    Figure 400425DEST_PATH_IMAGE003
    representing the phase shift angle combination of N sub-modules,
    Figure 137437DEST_PATH_IMAGE004
    the number of sub-modules is indicated,
    Figure 723139DEST_PATH_IMAGE005
    is shown as
    Figure 152983DEST_PATH_IMAGE006
    The harmonic coefficients of the primary currents of the sub-modules,
    Figure 207658DEST_PATH_IMAGE007
    indicates to be
    Figure 482781DEST_PATH_IMAGE006
    The harmonic coefficient of the primary current of the sub-module is taken as
    Figure 188569DEST_PATH_IMAGE006
    The reference phase shift angle of the individual sub-modules,
    Figure 523736DEST_PATH_IMAGE008
    wherein
    Figure 65707DEST_PATH_IMAGE009
    Is shown as
    Figure 206838DEST_PATH_IMAGE006
    The dc side voltage on the low side of the sub-module,
    Figure 704815DEST_PATH_IMAGE010
    is shown as
    Figure 289512DEST_PATH_IMAGE006
    The duty cycle of the sub-module;
    iteratively calculating the amplitude of the primary current harmonic vector under different phase shift angle combinations until a set condition is met;
    and executing the phase shift angle combination meeting the set condition as a reference phase shift angle combination of the next control period.
  2. 2. Method for the elimination of the first harmonic of the current of a DC-DC converter of MMC type according to claim 1, characterized in that said second step
    Figure 240150DEST_PATH_IMAGE006
    Duty cycle of sub-module
    Figure 184972DEST_PATH_IMAGE010
    The calculation formula (2) is specifically as follows:
    Figure 537456DEST_PATH_IMAGE011
    in the formula (I), the compound is shown in the specification,
    Figure 293054DEST_PATH_IMAGE012
    is shown as
    Figure 793305DEST_PATH_IMAGE006
    The dc side voltage on the high side of the sub-module,
    Figure 213922DEST_PATH_IMAGE013
    denotes the first
    Figure 517119DEST_PATH_IMAGE006
    The transmission power of the sub-modules is,
    Figure 630569DEST_PATH_IMAGE014
    representing the total transmission power of the N sub-modules.
  3. 3. The method for eliminating the primary current harmonic of the MMC-type DC-DC converter according to claim 1, wherein iteratively calculating the magnitudes of the primary current harmonic vectors at different phase shift angle combinations until a set condition is satisfied specifically comprises:
    setting an objective function based on a definitional representation of the primary current harmonic vector
    Figure 618116DEST_PATH_IMAGE015
    ，
    Figure DEST_PATH_IMAGE016
    Wherein
    Figure 655474DEST_PATH_IMAGE017
    To representThe phase shift angle of the first sub-module is set as the first current harmonic vector at the reference phase shift angle, and, similarly,
    Figure 716971DEST_PATH_IMAGE018
    representing a primary current harmonic vector when the phase shift angle of the Nth sub-module is set as a reference phase shift angle;
    and iteratively calculating the objective function value under different phase shift angle combinations until the objective function value is not greater than a set maximum error limit, so that the amplitude of the primary current harmonic vector meets a set condition.
  4. 4. Method for primary current harmonic cancellation in a DC-DC converter of the MMC type according to claim 3, characterized in that said maximum error limit is specifically set as:
    Figure 63638DEST_PATH_IMAGE019
    in the formula (I), the compound is shown in the specification,
    Figure 476165DEST_PATH_IMAGE020
    is the maximum error limit.
  5. 5. The method for eliminating the primary current harmonic of the MMC-type DC-DC converter according to claim 1 or 3, wherein iteratively calculating the magnitudes of the primary current harmonic vectors at different combinations of phase shift angles until the predetermined condition is satisfied specifically comprises:
    setting a unit stepping phase shift angle and iteration cycle time;
    calculating the amplitude of the primary current harmonic vector under the current phase shift angle combination by using the unit stepping phase shift angle;
    and judging whether the amplitude of the primary current harmonic vector under the current phase shift angle combination in the iteration cycle time meets a set condition, if not, continuously updating the phase shift angle combination, iteratively calculating the corresponding amplitude of the primary current harmonic vector until the set condition is met, and taking the phase shift angle combination meeting the set condition as the reference phase shift angle combination so as to carry out subsequent steps.
  6. 6. The method for eliminating the primary current harmonic of the MMC type DC-DC converter according to claim 5, wherein the calculation of the magnitude of the primary current harmonic vector under the current phase shift angle combination by using the unit step phase shift angle is specifically as follows:
    calculating the first current harmonic error of the phase shift angle combination in two iteration directions when the unit stepping phase shift angle is increased or decreased;
    and judging the magnitude of the primary current harmonic error in the two iteration directions, and selecting the iteration direction with the smaller primary current harmonic error for calculation in the next iteration calculation.
  7. 7. The method for eliminating the primary current harmonic of the MMC type DC-DC converter according to claim 6, characterized in that the primary current harmonic errors in two iteration directions are specifically:
    Figure 317213DEST_PATH_IMAGE021
    in the formula (I), the compound is shown in the specification,
    Figure 498796DEST_PATH_IMAGE022
    representing the first current harmonic error of the phase shift angle combination at increasing said unit step phase shift angle,
    Figure 750786DEST_PATH_IMAGE023
    representing the first current harmonic error of the phase shift angle combination in reducing the unit step phase shift angle,
    Figure 463658DEST_PATH_IMAGE024
    representing the unit step phase shift angle.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170099007A1 (en) * 2014-03-25 2017-04-06 Gneral Electric Technology GmbH Voltage source converter and control thereof
US20180269775A1 (en) * 2015-10-02 2018-09-20 General Electric Company Modular multilevel converter harmonic injection systems and methods
WO2019147144A1 (en) * 2018-01-25 2019-08-01 Riar Baljit Singh A multi-level modular converter
CN110995030A (en) * 2019-12-02 2020-04-10 上海交通大学 Solid-state transformer with medium-voltage direct current and true-dual ultra-low-voltage direct current ports
CN113078674A (en) * 2021-03-31 2021-07-06 武汉大学 Novel modular photovoltaic grid-connected system based on three-port power channel, namely control method
CN113852113A (en) * 2021-09-14 2021-12-28 广东电网有限责任公司阳江供电局 Modular distributed resistance energy consumption device, control method and storage medium
CN114448220A (en) * 2022-02-14 2022-05-06 广东电网有限责任公司 Method, device and equipment for eliminating primary current harmonic of modular multilevel DC converter and storage medium

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170099007A1 (en) * 2014-03-25 2017-04-06 Gneral Electric Technology GmbH Voltage source converter and control thereof
US20180269775A1 (en) * 2015-10-02 2018-09-20 General Electric Company Modular multilevel converter harmonic injection systems and methods
WO2019147144A1 (en) * 2018-01-25 2019-08-01 Riar Baljit Singh A multi-level modular converter
CN110995030A (en) * 2019-12-02 2020-04-10 上海交通大学 Solid-state transformer with medium-voltage direct current and true-dual ultra-low-voltage direct current ports
CN113078674A (en) * 2021-03-31 2021-07-06 武汉大学 Novel modular photovoltaic grid-connected system based on three-port power channel, namely control method
CN113852113A (en) * 2021-09-14 2021-12-28 广东电网有限责任公司阳江供电局 Modular distributed resistance energy consumption device, control method and storage medium
CN114448220A (en) * 2022-02-14 2022-05-06 广东电网有限责任公司 Method, device and equipment for eliminating primary current harmonic of modular multilevel DC converter and storage medium

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