CN105720599B - A kind of acquisition methods in modularization multi-level converter Power operation section - Google Patents
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- H—ELECTRICITY
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Abstract
The invention discloses a kind of acquisition methods in modularization multi-level converter Power operation section, comprise the steps：(1) basic parameter of modularization multi-level converter known to basis, the stable state analytical mathematical models of rotating coordinate system lower module multilevel converter are established；(2) the operation constraints to be considered is determined；(3) Power operation section under each constraints is calculated according to stable state analytical mathematical models；(4) the Power operation section under each constraints is taken into common factor, obtains and consider the Power operation sections for re-running constraints lower module multilevel converter more.The operation constraints that the present invention considers, by the stable state analytical mathematical models for establishing a set of rotating coordinate system lower module multilevel converter, and by take common factor obtain consider multiple constraint under the conditions of Power operation section, guidance is provided to determine and optimizing MMC basic parameters, there is stronger practical meaning in engineering.
Description
Technical Field
The invention relates to the technical field of power transmission and distribution of a power system, in particular to a method for acquiring a power operation interval of a modular multilevel converter.
Background
The flexible direct current transmission has the advantages of narrow transmission corridor, active and reactive decoupling control, no need of an alternating current system for providing commutation current, no commutation failure problem, capability of being connected with a passive or weak alternating current system and the like, so that the flexible direct current transmission engineering is widely practiced in the world and is an effective means for solving the energy environment crisis. Modular Multilevel Converters (MMC) have been proposed since 2001, and have gained extensive attention in academic and industrial fields due to their advantages such as low loss and modularization, and the same type of technologies as MMC or MMC are mostly adopted in flexible dc transmission projects which are put into operation and planned after 2010. According to the actual operation constraint conditions of the engineering, accurately calculating the power operation interval of the MMC is one of the problems to be solved urgently in the actual flexible direct-current transmission engineering. Analyzing the influence of the MMC parameters, such as the sub-module capacitance value, the bridge arm inductance value and the like, on the power running interval is also one of the problems to be solved urgently in the parameter design part of the actual flexible direct-current transmission project.
In the current engineering, a common means for calculating the power operation interval of the MMC is to draw a plurality of discrete operation points of the MMC through off-line simulation, so as to approximate the power operation interval boundary of the MMC. In order to obtain a relatively accurate result, more test conditions are required to be obtained, a large amount of manpower and material resources are consumed, once parameters are changed, a simulation model needs to be established again, and the work reproducibility is poor. Another common method is to calculate the power operation interval under the operation constraint condition through an MMC mathematical analysis model. However, most of the current accurate mathematical analysis models of the MMC are based on a three-phase stationary coordinate system, model variables are alternating current, and the expression of the model has the characteristic of strong non-linear time-varying property, so that a power operation interval cannot be conveniently solved according to operation constraint conditions. If a simplified MMC mathematical analysis model is adopted, the model generally only considers the external characteristics of the MMC, cannot reflect the internal characteristics of bridge arm current, sub-module capacitance voltage and the like of the MMC, and cannot solve a power operation interval according to constraint conditions of the bridge arm current or the sub-module capacitance voltage fluctuation and the like. Therefore, constructing an MMC accurate mathematical model which can be conveniently solved, and calculating the MMC power operation interval by combining with the actual operation constraint conditions of the engineering is an urgent problem to be solved in the engineering.
Disclosure of Invention
The invention aims to overcome the defects of the background technology, and provides a method for acquiring the power operation interval of a modular multilevel converter, which is based on an MMC steady-state mathematical analysis model under a rotating coordinate system, is accurate and easy to calculate and solve, considers the constraint conditions such as the maximum allowable value and the minimum allowable value of modulation ratio, the maximum allowable value of alternating current, the maximum allowable value of direct current, the maximum allowable value of sub-module capacitance voltage fluctuation, the maximum allowable value of bridge arm current and the like in the actual operation of a project, selects the intersection of the power operation intervals under each constraint condition by calculating the MMC power operation interval under each constraint condition, thereby determining the MMC power operation interval under the constraint condition of multiple operation, analyzing the influence of the basic parameters of the MMC on the power operation intervals, providing guidance for determining and optimizing the basic parameters of the MMC, and has stronger practical engineering significance.
The invention provides a method for calculating a power operation interval of a multilevel converter, which comprises the following steps:
(1) According to known MMC basic parameters, establishing a steady-state mathematical analysis model of the MMC under a rotating coordinate system;
(2) Determining operating constraints to be considered;
(3) Calculating power operation intervals under each constraint condition;
(4) Taking intersection of the power operation intervals under each constraint condition to obtain the power operation interval of the MMC under the multiple operation constraint condition;
(5) And (4) if the influence of the change of the basic parameters on the power operation interval is to be analyzed, updating the basic parameters, and repeating the steps (1) to (4) to obtain the power operation interval after the parameters are changed.
In the above technical solution, the expression of the MMC steady-state mathematical analysis model in the rotating coordinate system in step (1) is as follows:
the physical meaning of each parameter in the model is as follows: ω represents the ac grid voltage angular frequency; u. of s0 Representing the phase voltage amplitude of an alternating current system connected with the MMC; u. of dc0 Is the MMC rated direct current voltage; c arm ＝C sub /N，C sub Is the sub-module capacitance voltageThe value N is the number of sub-modules contained in each bridge arm, and the value is equal to the MMC level number minus 1; l is arm Is bridge arm inductance value, R arm Is the bridge arm equivalent resistance; l is T Is the equivalent inductance of the leakage reactance of the converter transformer, R T Is the loss equivalent resistance, K, of the converter transformer T Is the converter transformer transformation ratio; r s And L s Respectively an equivalent internal resistance and an equivalent internal inductance of the alternating current system; the above parameters are known basic parameters of the MMC. Other parameters are unknown parameters to be solved, and the physical meanings are as follows:andthe components of the x axis and the y axis of the frequency-doubled component of the total voltage of the capacitor of the upper bridge arm submodule are respectively;andthe components of the x axis and the y axis of the fundamental frequency component of the total capacitor voltage of the upper bridge arm submodule are respectively components;is the DC component of the total voltage of the sub-module capacitor of the upper bridge arm; i.e. i diffx20 And i diffy20 The x-axis and y-axis components of the double frequency component of the bridge arm loop current respectively; i.e. i diff00 Is the direct current component of the bridge arm circulation; m x20 And M y20 X-axis and y-axis components, respectively, which are double frequency components of the modulated signal; m x0 And M y0 The x-axis and y-axis components, respectively, of the fundamental frequency component of the modulated signal; i.e. i x0 And i y0 X-axis of fundamental frequency components of valve-side alternating currentAnd a y-axis component. Among the above unknown parameters, M x20 ，M y20 Frequency doubling component i for restraining bridge arm circular current diffx20 ，i diffy20 0, when bridge arm double frequency circulation suppression control (circulation suppression for short) is put into operation, M x20 And M y20 Is not 0, and i diffx20 And i diffy20 Is 0; when the circulation suppression is not applied, M x20 ，M y20 Are all 0, and the second harmonic component i of the bridge arm circulation diffx20 ，i diffy20 Is not 0. Therefore, the total number of variables to be solved of the mathematical analysis model under the MMC rotating coordinate system is 12, namely respectivelyi diffx20 (M x20 )，i diffy20 (M y20 )，i diff00 ，i x0 ，i y0 ，M x0 ，M y0 . MMC's upper bridge arm submodule piece electric capacity total voltageCapacitor total voltage of lower bridge arm submoduleBridge arm circulation i diff0 Upper bridge arm current i up0 Lower bridge arm current i dn0 Valve side alternating current i 0 The relation between the unknown parameters to be solved is as follows:
active power P of MMC transmission 0 And reactive power Q 0 The computational expression of (a) is:
in the above technical solution, the operation constraint conditions considered in the step (2) include the following constraints: the method comprises the following steps of modulation ratio maximum value and minimum value constraint, bridge arm current maximum value constraint, submodule capacitor voltage fluctuation maximum value constraint, alternating current maximum value constraint and direct current maximum value constraint. The mathematical expression form is as follows:
modulation ratio maximum and minimum constraints:
constraint of maximum value of bridge arm current: i up0,max |≤I arm,max ,|i dn0,max |≤I arm,max
And (3) restricting the maximum value of the voltage fluctuation of the sub-module capacitor: | Δ u c0，max |≤ΔU c,max (4)
And (3) maximum value constraint of alternating current:
and (3) limiting the maximum value of the direct current: i is dc ≤I dc,max
In the formula, M min And M max Respectively representing the minimum and maximum allowed values of the modulation ratio,a calculated value representing a modulation ratio; i.e. i up0,max And i dn0,max Respectively representing upper and lower bridge arm currents i up0 And i dn0 Maximum value of (1), I arm,max Representing the maximum allowable value of the bridge arm current; Δ u c0,max Representing the maximum value of the sub-module capacitor voltage fluctuation, Δ U c,max Representing a maximum allowable value of the sub-module capacitance voltage fluctuation;representing the amplitude of the alternating current, I ac,max Represents the maximum allowable value of the alternating current; i is dc Denotes direct current, I dc,max Indicating the maximum allowable value of the direct current. When the voltage-sharing effect of the sub-module capacitor is considered to be good, the maximum value delta u of the voltage fluctuation of the sub-module capacitor c0,max The total voltage of the bridge arm capacitor can also be used for representing:
in the above technical solution, the step (3) of calculating the power operation interval under each operation constraint condition includes the following substeps:
3.1 determining the parameter pairs at which the modulation ratio assumes the maximum permissible value<M x0,k ，M y0,k &In which<M x0,k ，M y0,k >, can be expressed as M in polar coordinate form x0,k ＝M max *cosθ k ，M y0,k ＝M max *sinθ k ，θ k E [0,2 π). Knowing 2 variables to be solved<M x0,k ，M y0,k &Solving the nonlinear equation set by iterative calculation according to the formula (1) to obtain all variables to be solved of the MMC model, and obtaining the alternating current i x0 And i y0 Then, calculating the active power P of the MMC according to the formula (3) 0 And reactive power Q 0 ；
3.2 similar to 3.1, the parameter pair at which the modulation ratio assumes the minimum allowable value can be determined<M x0,k ，M y0,k &In which M is x0,k ＝M min *cosθ k ，M y0,k ＝M min *sinθ k ，θ k E [0,2 pi ]), and the parameter pair when the AC current takes the maximum allowable value<i x0,k ，i y0,k &In which i x0,k ＝I ac,max *cosθ k ，i y0,k ＝I ac,max *sinθ k ，θ k E.g., [0,2 pi ]), solving the nonlinear equation set by iterative calculation according to formula (1), solving all variables to be solved of the MMC model, and obtaining the alternating current i x0 And i y0 Then, calculating the active power P of the MMC according to the formula (3) 0 And reactive power Q 0 ；
3.3 for the constraint condition of bridge arm current, since the values of 2 variables to be solved can not be obtained directly according to the constraint condition, the constraint condition of alternating current can be firstly utilized to determineSearch areas of fixed parameters, i.e. parameters of alternating current<i x0,k ，i y0,k > is on the planeUp scanning, wherein let i x0,k ＝I k *cosθ k ，i y0,k ＝I k *sinθ k ，I k ∈[0，I ac,max ]，θ k E.g. [0,2 π), using each pair<i x0,k ，i y0,k &Calculating all parameters to be solved of the MMC under the working condition, and calculating the maximum value i of the bridge arm current according to the expression of the upper bridge arm current and the lower bridge arm current in the formula (2) up,max And i dn,max Recording bridge arm current reaching its maximum value I arm,max Parameters corresponding to conditions under constraint conditions<i x0,k ，i y0,k &And calculating the active power P of the MMC according to the formula (3) 0 And reactive power Q 0 ；
3.4 for sub-module capacitor voltage ripple constraints, similar to 3.3, using each pair in the parameter search area in conjunction with the AC current constraint<i x0,k ，i y0,k &Calculating all parameters to be solved of the MMC under the working condition, calculating the maximum value of the sub-module capacitance voltage fluctuation according to the expression of the total capacitance voltage of the upper bridge arm sub-module and the lower bridge arm sub-module in the formula (2) and the formula (5), and recording the maximum value delta U of the sub-module capacitance voltage fluctuation c,max Parameter pair corresponding to working condition under constraint condition<i x0,k ，i y0,k >, calculating the active power P of the MMC according to the formula (3) 0 And reactive power Q 0 。
In the above technical solution, the determining the MMC power operating interval under the multiple operating constraints in step (4) includes the following substeps:
4.1, drawing an MMC power operation interval under each operation constraint condition;
4.2 according to the intersection point of the MMC power operation regions under each operation constraint condition, obtaining the intersection of the power operation regions under each operation constraint condition, namely obtaining the MMC power operation region under the multiple constraint condition.
In the above technical solution, the step (5) of changing the basic parameter of the MMC and analyzing the MMC power operation interval change includes the following substeps:
5.1 determining basic parameters of the MMC to be analyzed, such as a sub-module capacitance value, a bridge arm inductance value, a converter transformer leakage reactance, a converter transformer transformation ratio and the like;
and 5.2, changing the basic parameters, and repeating the steps (1) to (4) based on the new basic parameters of the MMC to obtain the MMC power operation interval under the new parameters.
The operation constraint conditions considered by the invention comprise a maximum allowable value and a minimum allowable value of a modulation ratio, a maximum allowable value of alternating current, a maximum allowable value of direct current, a maximum allowable value of sub-module capacitor voltage fluctuation and a maximum allowable value of bridge arm current, and basic parameters of the modular multilevel converter are known by establishing a set of steady-state mathematical analysis model of the modular multilevel converter under a rotating coordinate system, and the method comprises the following steps: the method comprises the steps that the voltage, the equivalent internal impedance, the direct current voltage, the transformation ratio, the leakage reactance and the loss of a converter transformer, the inductance value of a bridge arm reactor, the equivalent resistance value of a bridge arm, the capacitance value of a sub-module, the level number and whether the circulation suppression is input or not are judged, the power operation interval of the modular multilevel converter under each operation constraint condition can be obtained, and the power operation interval under the multiple constraint condition is considered through the intersection. By changing the basic parameters, the influence of the basic parameter change on the power operation interval of the modular multilevel converter can be analyzed, guidance is provided for determining and optimizing the basic parameters of the modular multilevel converter, and the method has strong engineering practical significance.
Drawings
Fig. 1 is a schematic flow chart of a method for calculating a power operation interval of a modular multilevel converter according to the invention;
FIG. 2 is a schematic diagram of calculating the MMC power operation region according to the operation constraint conditions in step (3) of the present invention;
FIG. 3 is a schematic diagram of the calculation result of the MMC power operation interval calculated according to the maximum allowable value of the modulation ratio in the operation constraint condition in step (3) of the present invention;
FIG. 4 is a schematic diagram of the calculation result of the MMC power operation interval calculated according to the minimum allowable value of the modulation ratio in the operation constraint condition in step (3) of the present invention;
FIG. 5 is a schematic diagram of the calculation result of calculating the MMC power operation region according to the maximum allowable value of the alternating current in the operation constraint condition in step (3) of the present invention;
FIG. 6 is a schematic diagram of a calculation result of calculating the MMC power operation interval according to the maximum allowable value of the DC current in the operation constraint condition in step (3) of the present invention;
FIG. 7 is a schematic diagram of a calculation result of calculating an MMC power operation interval according to the maximum allowable value of the bridge arm current in the operation constraint condition in step (3) of the present invention;
FIG. 8 is a schematic diagram of a calculation result of calculating an MMC power operation interval according to a maximum allowable value of the sub-module capacitor voltage fluctuation in the operation constraint condition in step (3) of the present invention;
FIG. 9 is a schematic diagram illustrating the calculation result of determining the MMC power operation region under the condition of considering the multiple operation constraints in step (4) of the present invention;
FIG. 10 is a schematic diagram of a calculation result of the MMC power operation interval under the consideration of the multiple operation constraint condition after increasing the bridge arm inductance value in step (5) of the present invention;
fig. 11 is a schematic diagram of a calculation result of the MMC power operation interval under the consideration of the multiple operation constraints after the capacitance value of the sub-module is reduced in step (5) of the present invention.
Detailed description of the invention
The invention is described in further detail below with reference to the figures and examples, which should not be construed as limiting the invention.
Referring to fig. 1, the method for calculating the power operation interval of the modular multilevel converter of the invention comprises the following steps:
step (1): establishing a mathematical analysis model (formula 1 and formula 2) of the modular multilevel converter under a rotating coordinate system, and knowing basic parameters of the modular multilevel converter, including alternating current system voltage, an equivalent internal resistance value, an equivalent internal inductance value, direct current voltage, a converter transformer transformation ratio, a leakage reactance equivalent inductance value, a loss equivalent resistance value, a bridge arm reactor inductance value, a bridge arm equivalent resistance value, a sub-module capacitance value, a level number and whether to put into circulation suppression.
Step (2): and determining operation constraint conditions (formula 3) to be considered, wherein the operation constraint conditions comprise modulation ratio maximum allowable value and minimum allowable value constraints, alternating current maximum allowable value, direct current maximum allowable value, bridge arm current maximum allowable value and submodule capacitor voltage fluctuation maximum allowable value.
And (3): based on a mathematical analysis model of the modular multilevel converter under a rotating coordinate system, calculating the power operation interval of the modular multilevel converter under each operation constraint condition, and the specific process is as follows:
3.1 determining the parameter pairs at which the modulation ratio assumes the maximum permissible value<M x0,k ，M y0,k &Solving the nonlinear equation set by iterative computation according to a formula (1), so that all variables to be solved of the MMC model can be solved, and the active power and the reactive power of the MMC are calculated according to the alternating current;
3.2 similar to 3.1, the parameter pair at which the modulation ratio takes the minimum allowable value can be determined<M x0,k ，M y0,k &And parameter pair when the AC current takes the maximum allowable value<i x0,k ，i y0,k &Solving the nonlinear equation set by iterative computation according to a formula (1), solving all variables to be solved of the MMC model, and computing the active power and the reactive power of the MMC according to alternating current;
3.3 for the constraint condition of the maximum allowable value of the bridge arm current, calculating the MMC power operation interval by combining the constraint condition of the maximum allowable value of the alternating current, firstly making alternating current parameters pair<i x0,k ，i y0,k &At the planeUp scanning, calculating each pair<i x0,k ，i y0,k >, lower bridge arm currentMaximum value, recording the parameters corresponding to the working conditions when the bridge arm current reaches its constraint condition<i x0,k ，i y0,k &Calculating the active power and the reactive power of the MMC;
3.4 for the maximum allowable value constraint of the sub-module capacitor voltage fluctuation, similar to 3.3, calculating each pair by combining the maximum value constraint conditions of the alternating current<i x0,k ，i y0,k >, the maximum value of the capacitance voltage fluctuation of the lower sub-module, and recording the parameter pair corresponding to the working condition that the capacitance voltage fluctuation of the sub-module reaches the constraint condition<i x0,k ，i y0,k &And calculating the active power and the reactive power of the MMC.
And (4): taking intersection of the power operation intervals under each constraint condition to obtain the power operation interval of the modular multilevel converter under the multiple operation constraint condition;
and (5): and (4) if the influence of the change of the basic parameters on the power operation interval is to be analyzed, updating the basic parameters, and repeating the steps (1) to (4) to obtain the power operation interval after the parameters are changed.
The specific embodiments described herein are merely illustrative of the invention and do not delimit the invention. The steps of the method for calculating the power interval of the modular multilevel converter provided by the invention are shown in fig. 2.
Step (1): and establishing a mathematical analysis model of the modular multilevel converter under the rotating coordinate system according to the formula 1 and the formula 2. The basic parameters of the modular multilevel converter are known, as shown in table one.
Table-modular multi-level converter basic parameter
Step (2): the operating constraints under consideration are entered as shown in table two.
Table two operating constraints
| Constraint conditions | Detailed description of the invention |
| Modulation ratio | [0.8，1] |
| Current on the AC side | 1.5pu |
| Direct Current (DC) | 1.1pu |
| Submodule capacitor voltage ripple | ±13％ |
| Bridge arm current | 2.4kA |
And (3): and calculating and drawing the power operation interval of the modular multilevel converter under each operation constraint condition, as shown in fig. 3-8.
And (4): determining the intersection of the power operation intervals of the modular multilevel converter under each operation constraint condition to obtain the power operation interval of the modular multilevel converter under the multiple constraint conditions, as shown by the shaded part in fig. 9. It can be seen that the power operation interval of the modular multilevel converter is mainly determined by constraint conditions of the maximum value and the minimum value of the modulation ratio and the maximum value of the direct current, and on the premise of meeting the constraint conditions of the modulation ratio and the direct current, other operation constraint conditions can be met.
And (5): increasing the inductance value of the bridge arm reactor to 100mH, and repeating the steps (1) to (4) to obtain the power operation interval of the modular multilevel converter with the increased bridge arm inductance, as shown by the shaded part in FIG. 10, it can be seen that the operation interval is reduced compared with the operation interval when the bridge arm reactor takes 60 mH. Reducing the sub-module capacitance value to 9mF, and repeating the steps (1) to (4) to obtain the power operation interval of the modular multilevel converter after the sub-module capacitance value is reduced, as shown by the shaded part in fig. 11, it can be seen that the operation interval is reduced compared with the time when the sub-module capacitance value is 11 mF.
Those not described in detail in this specification are within the skill of the art. It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (4)
1. A method for obtaining a power operation interval of a modular multilevel converter is characterized by comprising the following steps:
(1) Establishing a steady-state mathematical analysis model of the modular multilevel converter under a rotating coordinate system according to known basic parameters of the modular multilevel converter;
(2) Determining operating constraints to be considered;
(3) Calculating power operation intervals under each constraint condition according to the steady-state mathematical analysis model;
(4) Taking intersection of the power operation intervals under each constraint condition to obtain the power operation interval of the modular multilevel converter under the multiple operation constraint condition;
the steady-state mathematical analysis model comprises:
wherein, omega is the angular frequency of the alternating current network voltage; u. of s0 The phase voltage amplitude of an alternating current system connected with the MMC; u. of dc0 Rated direct current voltage for MMC; c arm ＝C sub /N，C sub The sub-module capacitance voltage value is obtained, N is the number of sub-modules contained in each bridge arm, and the number is equal to the MMC level number minus 1; l is arm Is bridge arm inductance value, R arm The equivalent resistance of the bridge arm; l is T For equivalent inductance of leakage reactance of converter transformer, R T For loss equivalent resistance, K, of converter transformer T Converting the ratio of the converter transformer; r s And L s Are respectively asEquivalent internal resistance and equivalent internal inductance of the alternating current system; andthe components of the x axis and the y axis of a frequency-doubled component of the total voltage of the capacitor of the sub-module of the upper bridge arm are respectively;andrespectively representing the x-axis component and the y-axis component of the fundamental frequency component of the total capacitor voltage of the upper bridge arm submodule;the direct current component of the total voltage of the capacitor of the sub-module of the upper bridge arm is the direct current component of the total voltage of the capacitor of the sub-module of the upper bridge arm; i.e. i diffx20 And i diffy20 The components of the x axis and the y axis of the double frequency component of the bridge arm circulation are respectively; i all right angle diff00 Is the direct current component of the bridge arm circulation; m is a group of x20 And M y20 X-axis and y-axis components, respectively, of a double frequency component of the modulated signal; m x0 And M y0 The x-axis and y-axis components of the fundamental frequency component of the modulated signal, respectively; i.e. i x0 And i y0 The x-axis and y-axis components, respectively, of the fundamental frequency component of the valve-side alternating current.
2. The acquisition method according to claim 1, characterized by further comprising, after step (4), the steps of:
(5) Updating the basic parameters, repeating the steps (1) to (4) and obtaining the power operation interval after the parameters are changed.
3. The acquisition method according to any one of claims 1-2, wherein the operating constraints include: the method comprises the following steps of modulation ratio maximum value and minimum value constraint, bridge arm current maximum value constraint, submodule capacitor voltage fluctuation maximum value constraint, alternating current maximum value constraint and direct current maximum value constraint.
4. The acquisition method according to claim 3,
modulation ratio maximum and minimum constraints:
constraint of maximum value of bridge arm current: i up0,max |≤I arm,max ,|i dn0,max |≤I arm,max
And (3) restricting the maximum value of the voltage fluctuation of the sub-module capacitor: | Δ u c0，max |≤ΔU c,max ；
AC current maximum value constraint:
and (3) limiting the maximum value of the direct current: i is dc ≤I dc,max
Wherein M is min And M max Respectively a minimum allowed value and a maximum allowed value of the modulation ratio,is a calculated value of the modulation ratio; i.e. i up0,max And i dn0,max Respectively an upper bridge arm current and a lower bridge arm current i up0 And i dn0 Maximum value of (1), I arm,max The maximum allowable value of the bridge arm current is obtained; Δ u c0,max Is the maximum value of the sub-module capacitance voltage fluctuation, delta U c,max The maximum allowable value of the voltage fluctuation of the capacitor of the submodule is;is the amplitude of the alternating current, I ac,max Is the maximum allowable value of the alternating current; I.C. A dc Is a direct current, I dc,max Is a direct currentThe maximum allowable value of the current.
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| CN109149981B (en) * | 2018-08-20 | 2019-10-25 | 华中科技大学 | A kind of Multipurpose Optimal Method based on genetic algorithm suitable for MMC |
| CN109507481B (en) * | 2018-12-18 | 2020-01-10 | 华中科技大学 | MMC harmonic stability evaluation method |
| CN110690724B (en) * | 2019-10-29 | 2021-11-12 | 国网新疆电力有限公司 | Converter station safety and stability control method considering MMC internal dynamic constraints |
| CN110784116B (en) * | 2019-10-29 | 2020-12-22 | 国网新疆电力有限公司 | Method and system for determining converter station working domain considering MMC internal dynamic constraint |
| CN110994660A (en) * | 2019-11-07 | 2020-04-10 | 长沙理工大学 | MMC power operation interval optimization method based on energy flow law |
| CN112016043B (en) * | 2020-07-06 | 2023-09-19 | 北京交通大学 | Method for calculating steady-state fault current of modularized multi-level converter |
| CN117350223A (en) * | 2023-09-13 | 2024-01-05 | 广东电网有限责任公司电力科学研究院 | Multi-objective optimization parameter design method for modularized multi-level converter based on SiC MOSFET |
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